Details of a Researcher - Toda, Masahiro

Papers - Toda, Masahiro

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Combined presigmoid retrolabyrinthine and retrosigmoid approach for large vestibular schwannoma: a case report.

Kojima M, Tamura R, Ishikawa K, Sayanagi T, Karatsu K , Ueda R, Toda M.

Front Surg (Frontiers Media S.A.) 2026 ( 13 ) 2026.05

Research paper (scientific journal), Last author, Accepted

Access to Document (DOI)

Enhanced Precision in Personalized Intraoperative Monitoring of Facial Nerves: A Comparative Analysis of fMRI-Guided and Conventional Electrode Placement for Transcranial Motor-Evoked Potentials During Skull Base Surgery

Sayanagi T, Tamura R, Tomio R, Sogano J, Karatsu K, Ishikawa K, Kosugi K, Akiyama T, Ueda R, Toda M

Operative Neurosurg (Hagerstown, MD) 2026.03

Research paper (scientific journal), Last author, Accepted

Access to Document (DOI)

Matrix metalloproteinase-13 is an unfavorable prognostic factor in chordoma by digesting growth inhibitory collagens

Oishi Y, Kawaai K, Tamura R, Kuroda Y, Noji S, Toda M, Matsuo K

Cancer Mesecine (Wiley) 15 ( 2 ) e71662 2026.02

Research paper (scientific journal), Accepted

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Diverse NF2 alterations in cranial schwannomas: a two-case series of germline whole-gene deletion and somatic in-frame deletion

Nakamura K, Tamura R, Sogano J, Yo M, Karatsu K, Takamatsu R, Nishihara H, Toda M

Brain Tumor Pathol (Springer-Verlag Tokyo) 2026.01

Last author, Accepted

The "en bloc" shift: ipsilateral and contralateral abducens nerve palsy following microvascular decompression for trigeminal neuralgia caused by vertebrobasilar dolichoectasia

Kosugi K, Ito S, Fukumoto H, Sayanagi T, Ishikawa K, Akiyama T, Toda M

J Neurosurg Case Lessons (American Association of Neurosurgeons dba Journal of Neurosurgery Publishing Group,) 2026

Research paper (scientific journal), Last author, Accepted

Surgical treatment of apical petrositis via the anterior transpetrosal approach: a case report.

Enomoto T, Tamura R, Iwama T, Karatsu K, Nakayama Y, Takahashi S, Kinno R, Toda M.

Surgical Neurol Int (Scientific Scholar LLC) 2026

Research paper (scientific journal), Last author, Accepted

Intraoperative Language mapping in a Japanese-English-French trilingual patient with a left Temporal lobe glioma: a case report

Yamamoto K, Tamura R, Ganaha S, Karatsu K, Ishizawa T, Kojima K, Ando M, Kosugi K, Kitamura Y, Ueda R, Ishikawa A, Imanishi T, Tsuji T, Toda M

Brain Struct Funct. (Springer-Verlag) 230 ( 9 ) 184 - 184 2025.11

Research paper (scientific journal), Last author, Accepted

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Comprehensive genetic analysis of NF2 in sporadic vestibular schwannoma

Wakabayashi T, Wasano K, Nakamura K, Hosoya M , Kawano R, Takamatsu R, Ueno M, Shimanuki N. Marie, Tsuzuki N, Nishiyama T, Akiyama T, Toda M, Nishihara H, Ozawa H, Oishi N

Laryngoscope Investig Otolaryngol (Wiley) 10 ( 5 ) e70625 2025.09

Research paper (scientific journal), Accepted

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D-serine suppresses one-carbon metabolism by competing with mitochondrial L-serine transport

Suzuki M, Adachi K, Wiriyasermukul P, Fukumura M, Tamura R, Hirano Y, Aizawa Y, Miyamoto T, Taniguchi S, Toda M, Homma H, Kanekura K, Yasuoka K, Kanai T, Sugimoto M, Nagamori S, Yasui M, Sasabe J

eLife (eLife Sciences Publications, Ltd.) 2025.09

Research paper (scientific journal), Accepted

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Genetic and clinical characteristics of cranial nerve schwannoma harboring SH3PXD2A-HTRA1 fusion gene

Sogano J, Tamura R, Yo M, Nakamura K, Fukada I, Ueno T, Hino U, Tomioka A, Karatsu K, Nagao A, Ueda R, Nishihara H, Toda M

Acta Neuropathol (Berlin : Springer Verlag) 150 ( 1 ) 31 - 31 2025.09

Accepted

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Vagus nerve stimulation in KCNB1-related developmental and epileptic encephalopathy: A case of seizure reduction and review of literature

Sayanagi T, Kosugi K, Ogawa E, Takenouchi T, Yamada M, Kosaki K, Sugiyama I, Toda M

Epilepsy Behav Rep (Elsevier Inc.) 32 100826 2025.08

Research paper (scientific journal), Last author, Accepted

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Perampanel for alleviation of secondary injury in traumatic brain injury (PEACE-TBI): a protocol for a phase-II multicentre randomised clinical trial

Yamamoto R, Tamura R, Morimoto Y, Nakaya M, Terao Satoshi, Shoji T, Kanazawa T, Sasao R, Inaba M, Shimizu M, Kuranari Y, Katayama M, Ueno K, Oishi Y, Nakamura A, Kikuo Y, Murakami R, Homma K, Wakahara S, Ishikawa K, Kosugi K, Toda M, Ozaki T, Sasaki Junichi

BMJ Open (BMJ Publishing Group Ltd) 15 ( 8 ) e105190 2025.08

Research paper (scientific journal), Accepted

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Variations in venous anatomy associated with the suboccipital transhorizontal fissure approach : Imaging and cadaveric studies with clinical application

Sogano J, Tamura R, Mizutani K, Kitamura Y, Ueda R, Toda M

Acta Neurochir(Wein) (Wien, Springer.) 167 ( 204 ) 2025.07

Last author, Accepted

A Cautionary Note on the Indication for Deep Brain Stimulation in Parkinsonism Patients with SLC9A6 Gene Mutations

Okusa S,Toda M

J Mov Di (ML Communications) 18 ( 3 ) 268 - 270 2025.04

Research paper (scientific journal), Accepted

Gene therapy and genome-editing for schwannoma in NF2-related schwannomatosis: current understanding and future directions

Tamura R, Yo M, Toda M

J Neurooncol (Boston : M. Nijhoff) 2025.03

Accepted

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Angiographical Investigation of Vagal and Carotid Body Paragangliomas

Yamamoto K, Akiyama T, Mizutani K, Ozawa H, Toda M

J Neuroendovasc Ther (Nihon Nō Shinkei Kekkannai Chiryō Gakkai) 19 ( 1 ) 2025.03

Accepted

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Anterior transpetrosal approach

田村亮太、戸田正博

脳神経外科速報 (メディカ出版) 35 ( 2 ) 192 - 203 2025.02

Research paper (scientific journal), Accepted

Optimal Delivery of Pain Management in Schwannomatosis: A Literature Review

Hino U, Tamura R, Toda M

Ther Clin Risk Manag (Albany, Auckland : Dove Medical Press) 2025 ( 21 ) 61 - 68 2025.01

Research paper (scientific journal), Joint Work, Accepted

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Variable anatomical features of acromegaly in the nasal cavity and paranasal sinuses: implications for endoscopic endonasal transsphenoidal surgery

Takahara K,Tamura R, Isomura E, Kitamura Y, Ueda R, Toda M

Acta Neurochir (Wien) (Wien, Springer) 166 ( 1 ) 408 2024.10

Research paper (scientific journal), Joint Work, Accepted

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Risk factors of postoperative trigeminal neuropathy in surgical treatment of trigeminal schwannomas

Shibao S, Ueda R, Toda M, Yoshida K

Acta Neurochir (Wien) (Wien, Springer) 166 ( 1 ) 387 2024.09

Research paper (scientific journal), Joint Work, Accepted

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Development of microsurgical forceps equipped with haptic technology for in situ differentiation of brain tumors during microsurgery

Ezaki T, Kishima K, Shibao S, Matsunaga T, Pareira S E , Kitamura Y, Nakayama Y, Tsuda N, Takahara K, Iwama T, Sampetrean O, Toda M, Ohnishi K, Shimono T, Sasaki H

Sci Rep (Springer Nature) 14 ( 1 ) 21430 2024.09

Research paper (scientific journal), Joint Work, Accepted

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Upright CT-based evaluation of the effects of posture on skull-base reconstruction after endoscopic endonasal surgery

Takahara K, Mizutani K,Yamada Y, Yamada M, Yokoyama Y, Yoshida K, Kosugi K, Ueda R, Toda M, Jinzaki M

Sci Rep (Springer Nature) 14 ( 1 ) 20303 2024.09

Joint Work, Accepted

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Natural history of hearing and tumor growth in vestibular schwannoma in neurofbromatosis type 2‑related schwannomatosis

Wakabayashi T, Tamura R, Karatsu K, Hosoya M, Nishiyama T, Inoue Y, Ogawa K, Kanzaki J, Toda M, Ozawa H, Oishi N

Eur Arch Otorhinolaryngol 281 ( 6 ) 4175 - 4182 2024.08

Research paper (scientific journal), Joint Work, Accepted

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Phase I/II Study of a Vascular Endothelial Growth Factor Receptor Vaccine in Patients With NF2-Related Schwannomatosis

Tamura R, Yamanobe Y, Fujioka M, Morimoto Y, Fukumura M, Nakaya M, Oishi Y, Sato M, Ueda R. Fujiwara H, Hikichi T, Noji S, Oishi N, Ozawa H, Ogawa K, Kawakami Y, Ohira T, Yoshida K, Toda M

J Clin Oncol 42 ( 21 ) 2578 - 2587 2024.05

Research paper (scientific journal), Joint Work, Corresponding author, Accepted

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Optimizing perampanel monotherapy for surgically resected brain tumors

Hino U, Tamura R, Kosugi K, Ezaki T, Karatsu K, Yamamoto K, Azuna T, Toda M

Mol Clin Oncol 20 ( 6 ) 42 2024.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 2049-9450

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Chordoma cells possess bone-dissolving activity at the bone invasion front.

Kawaai K, Oishi Y, Kuroda Y, Tamura R, Toda M, Matsuo K

Cell Oncol(Dordr) (Dordrecht : Springer) 47 ( 5 ) 1663 - 1677 2024.04

Research paper (scientific journal), Joint Work, Corresponding author, Accepted

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Status of alternative angiogenic pathways in glioblastoma resected under and after bevacizumab treatment

Ezaki T, Tanaka T, Tamura R, Ohara K, Yamamoto Y, Takei J, Morimoto Y, Imai R, Kuranai Y, Akasaki Y, Toda M, Murayama Y, Miyake K, Sasaki H

Brain Tumor Pathol 41 ( 2 ) 61 - 72 2024.04

Research paper (scientific journal), Joint Work, Accepted

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The role of genetic analysis in distinguishing multifocal and multicentric glioblastomas: An illustrative case.

Karatsu K, Tamura R, Yo M, Nogawa H, Hino U, Kitamura Y, Ueda R, Toda M

Case Rep Oncol　2024 (Karger) 17 ( 1 ) 113 - 121 2024.01

Research paper (scientific journal), Joint Work, Accepted

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Aneurysmal subarachnoid hemorrhage occurring during sleep: Clinical characteristics and risk factors.

Inamasu J, Akiyama T, Akaji K, Inaba M, Nishimoto M, Kojima A, Terao S, Hayashi T, Mizutani K, Toda M

J Stroke Cerebrovasc Dis (Elsevier) 33 ( 4 ) 107591 2024.01

Joint Work, Accepted

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Probable sporadic creutzfeldt-jakob disease presenting as refractory status epilepticus in a post-stroke epilepsy patient: A case report.

Sogano J, Kosugi K, Okano A, Nihei Y, Watanabe N, Nakahara J, Toda M

NMC Case Rep J 10 349 - 354 2023.12

Joint Work, Accepted

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A case of symptomatic intraluminal Internal carotid artery thrombus in a patient with essential thrombocythemia surgically treated by CEA

Takahashi S, Katsumata M, Nogawa H, Takahara K, Nakahara J, Toda M

Case reports in neurological medicine 2023 Article ID 9152009 2023.11

Joint Work, Accepted

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Medical Treatments for Malignant Brain Tumor.

Kitamura Y, Toda M

Brain Nerve 75 ( 5 ) 561 - 566 2023.10

Joint Work, Accepted

Clinical Effectiveness of Mirogabalin Besylate for Trigeminal Neuropathy after Skull Base Surgery: Illustrative Cases

Karatsu K, Tamura R, Miyauchi T, Sogano J, Hino U, Iwama T, Toda M

Medicines 10 ( 8 ) 48 2023.08

Accepted

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A case of moyamoya disease diagnosed as cerebral infarction in the early postpregnancy period and surgically treated by bilateral revascularization after term delivery.

Takahashi S, Katsumata M, Mizuguchi Y, Toda M

Clin Neurol Neurosurg (Elsevier) 231 107859 2023.08

Joint Work, Accepted

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"Missing-Piece” Sign with dural arteriovenous fistula at craniocervical junction: A case report

Tezuka T, Nukariya T, Katsumata M, Miyauchi T, Tokuyasu D, Azami S, Izawa Y, Nagoshi N, Fujiwara H, Mizutani K, Akiyama T, Toda M, Nakahara J, Nishimoto Y

J Stroke Cerebrovasc Dis (Elsevier) 32 ( 7 ) 107152 2023.07

Joint Work, Accepted

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Correlation between genotype and phenotype with special attention to hearing in 14 Japanese cases of NF2-related schwannomatosis

Oishi N, Noguchi M, Fujioka M, Nara K, Wasano K, Mutai H, Kawakita R, Tamura R, Karatsu K, Morimoto Y, Toda M, Ozawa H, Matsunaga T

Sci Rep (Nature Portfolio) 13 ( 1 ) 6595 2023.04

Joint Work, Accepted

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Neuroprotective effects of genome-edited human iPS cell-derived neural stem/progenitor cells on traumatic brain injury.

Imai R, Tamura, R, Yo M, Sato M, Fukumura M, Takahara K, Kase Y, Okano H, Toda M

Stem Cells (Oxford Univ Press) 2023.04

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Novel postoperative serum biomarkers in Atypical meningiomas: A Multicenter study.

Chang Ick W, Byun Kyung H, Lee Ho J, Park Chul-Kee, Kim Ah I, Kim Chae-Yong, Chang Hee J, Kang Seok-Gu, Lee Hyung S, Kuranari Y, Tamura R, Toda M, Wee Woo C, Yoon In H

Neurosurgery (Lippincott Williams & Wilkins) 2023.03

Joint Work

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Endoscopic Occipital Transtentorial Approach for Supracerebellar Lesion.

Takahara K, Iwama T, Miwa T, Toda M,

NMC Case Rep J 2023.03

A simple combined approach using anterior transpetrosal and retrosigmoid approach: A case report.

Tamura R, Ueda R, Karatsu K, Sayanagi T, Takahara K, Hino U, Iwama T, Nogawa H, Nakaya M, Horiguchi T, Toda M

Front. Surg (FRONTIERS MEDIA SA) 10 2023.02

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Safety, feasibility, and efficacy of additional extraventricular anterior commissurotomy with　corpus callosotomy.

Kosugi K, Yoshitomi M, Takayama Y, Iijima K, Kimura Y, Kaneko Y, Toda M, Iwasaki M

Oper Neurosurg ( LIPPINCOTT WILLIAMS & WILKINS) 24 ( 2 ) e68 - e74 2023.02

Joint Work

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Prognostic Significance of Preoperative Neutrophil-to-Lymphocyte Ratio in Surgically Resected Schwannomas.

Takahara K, Tamura R, Kuranari Y, Karatsu K, Akiyama T, Toda M

Frontiers in Oncology (FRONTIERS MEDIA SA) 2023

Joint Work

Volumetric measurement of paranasal sinuses and its clinical significance in pituitary neuroendocrine tumors operated using an endoscopic endonasal approach

Nakaya M, Tamura R, Takahara K, Senuma T, Yoshida K, Kitamura Y, Ueda R, Toda M

Front Neurol (Frontiers Media SA) 2023

Joint Work

Clinical, histopathological and molecular risk factors for recurrence　of pilocytic astrocytomas: brainstem/spinal location, nestin expression and gain of 7q and 19 are associated with early tumor recurrence

Tamura R, Iwatani A, Ohara K, Nishimoto M, Pareira ES, Miwa T, Tsuzaki N, Morimoto Y, Toda M, Okano H, Nakamura M, Yoshida K, Sasaki H

Brain Tumor Pathol (SPRINGER JAPAN KK) 2023

Joint Work

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Subarachnoid hemorrhage triggers neuroinflammation of the entire cerebral cortex, leading to neuronal cell death

Yamada H, Kase Y, Okano Y, Kim D, Goto M, Takahashi S, Okano H, Toda M

Inflammation and Regeneration (BMC) 42 - 61 2022.12

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The role of optimal cut-off diagnosis in 11C-methionine PET for differentiation of intracranial brain tumor from non-neoplastic lesions before treatment

Tomohiro Yamaki, Yoshinori Higuchi, Yasuo Iwadate, Tomoo Matsutani, Seiichiro Hirono, Hikaru Sasaki, Masahiro Toda, Shinji Onodera, Nobuo Oka, Shigeki Kobayashi

Clinical Imaging (Elsevier Science Inc.) 92 124 - 130 2022.12

Joint Work

Gene therapy using genome-edited iPS cells for targeting malignant glioma

Tamura R, Miyoshi H, Imaizumi K, Yo M, Kase Y, Sato T, Sato M, Morimoto Y, Sampetrean O, Kohyama J, Shinozaki M, Miyawaki A, Yoshida K, Saya H, Okano H, Toda M

Bioengineering & Translational Medicine (Wiley) e10406 2022.09

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Surgical Planning and Simulation of Endonasal Endoscopic Surgery for Pituitary Adenoma with Cavenous Sinus Invasion

Tamura R,Oda H,Kosugi K,Toda M

Operative　Neurosurgery 23 ( 4 ) e276 - e282 2022.07

Joint Work, Corresponding author, Accepted

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Role of endovascular treatment for ruptured aneurysms involving the anterior spinal artery at the craniocervical junction

Mizutani K , Akiyama T, Tomita H, Toda M

J Neuroradiol (Amer Soc Neuroradiology) 50 ( 1 ) 44 - 49 2022.04

Joint Work, Accepted

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Imaging of the venous plexus of Rektorzik using CT-digital subtraction venography:a retrospective study

Ryota Imai,Katsuhiro Mizutani,Takenori Akiyama,Takashi Horiguchi,Yoshifumi Takatsume,Masahiro Toda

Neuroradiology (Spriger) 64 ( 10 ) 1961 - 1968 2022.04

Research paper (scientific journal), Joint Work

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Stepwise improvement in limb shaking achieved by staged angioplasty for severe carotid stenosis.

Takahara K, Akiyama T, Yoshida K, Yamada H, Oishi Y, Kuranari Y, Katsumata M, Toda M

Neuroradiol J (Sage Publications inc.) 35 ( 2 ) 260 - 263 2022.04

Joint Work

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治療前の非腫瘍性病変からの頭蓋内脳腫瘍の鑑別のための11C-メチオニンPETにおける最適なカットオフ診断の役割

山木智宏, 樋口義則, 岩立康夫, 松谷智生, 広野誠一郎 , 佐々木光, 戸田正博 , 小野寺真二 , 岡信夫 , 小林茂樹

臨床イメージング (エルゼビア・サイエンス・パブリッシング・カンパニー) 2022

Accepted

Cone-beam computed tomography fusion technique for vascular assessment of skull base meningiomas

Yoshida K, Akiyama T, Takahashi S, Miwa T, Horiguchi T, Sasaki H, Toda M

World Neurosurg (Elsevier Science Inc.) S1878-8750 ( 21 ) 61 - 69 2021.04

Research paper (scientific journal), Joint Work

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A novel histopathological classification of meningiomas based on dural invasion

Murase M, Tamura R, Kuranari Y, Sato M, Ohara K, Morimoto Y, Yoshida K, Toda M

J Clin Path 74 ( 4 ) 238 - 243 2021.04

Research paper (scientific journal), Joint Work, Accepted

Aims Histological invasion into the adjacent brain parenchyma is frequently investigated in meningioma because it is an important morphological criterion for grade II meningioma according to the 2016 WHO classification. However, few studies have focused on dural invasion of meningiomas. Herein, we propose a novel histopathological classification based on dural invasion of meningiomas. Methods Forty-nine cases with WHO grade I meningiomas who underwent Simpson grade I removal were collected. After the meningeal layer (ML) and periosteal layer (PL) of dura mater were visualised by Masson's trichrome stain, we evaluated the depth (to the ML and PL) and the patterns (1, expanding; 2, infiltrating) of dural invasion of meningiomas using serial paraffin sections. Invasion-associated markers, including Ki-67, matrix metalloproteinase (MMP)-1, MMP-9 and MMP-13, aquaporin 1 and Na-K-2Cl cotransporter, were quantitatively analysed by immunohistochemistry. Results Thirty-five cases (71.4%) showed the dural invasion. In 27 of these 35 cases (77.1%), dural invasion was localised in ML. Type 1 (expanding type) and type 2 (infiltrating type) invasions were observed in 23 and 12 cases, respectively. The recurrence rate in cases with type 2 invasion was significantly higher than that in cases with type 1 invasion. The percentage of MMP-1-positive tumour cells was also significantly higher in cases with dural invasion than those without, suggesting involvement of MMP-1 in dural invasion. Conclusions We quantitatively evaluated the depth and patterns of dural invasion in meningiomas. The patterns of dural invasion were associated with meningioma recurrence.

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Angio-anatomical study of the pterygovaginal artery based on cone-beam computed tomography

Yoshida K, Akiyama T, Raz E, Kamamoto D, Ozawa H, Toda M

Neruoradiology (Neuroradiology) 2021.02

Research paper (scientific journal), Joint Work, Accepted, ISSN 00283940

Purpose: To investigate the anatomical characteristics and clinical implications of the pterygovaginal artery (PtVA), a recurrent branch from the distal internal maxillary artery (IMA), which courses through the pterygovaginal canal that connects the pterygopalatine fossa and nasopharynx. Methods: Eighty-two patients with 90 sides of cone-beam computed tomography (CBCT) reconstructed from rotational angiography of the external or common carotid artery with a field of view covering the pterygopalatine fossa were retrospectively reviewed. The origin from the IMA, branching type, distribution, and anastomoses was evaluated. The underlying lesions were 36 hypervascular lesions with possible supply from PtVA (17 cavernous sinus arteriovenous fistulas (AVFs), 6 anterior condylar AVFs, and 13 nasopharyngeal, parasellar, or paraclival tumors) and 46 other diseases. Results: PtVA was identified in 75 sides (83%). It originated from the pterygopalatine segment of the IMA in 45 sides (60%) and from the pterygoid segment in 30 sides (40%). It arose independently (77%), sharing the common trunk with the Vidian artery (15%) or with other branches. It ran posteromedially through the pterygovaginal canal to supply the mucosa over the nasopharyngeal roof, the choanae, and the pharyngeal ostium of the eustachian tube. It anastomosed with the ascending pharyngeal artery (n=37), the accessory meningeal artery (n=7), and the mandibular artery from the petrous internal carotid artery (n=2). It served as a feeder of osseous AVFs and skull base tumors. Conclusion: PtVA was often identified by CBCT even in normal anatomy. Its detailed angio-anatomy could be evaluated in the presence of parasellar or paraclival hypervascular lesions.

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Recent progress in the research of suicide gene therapy for malignant glioma

Tamura R., Miyoshi H., Yoshida K., Okano H., Toda M.

Neurosurgical Review (Neurosurgical Review) 44 ( 1 ) 29 - 49 2021.02

ISSN 03445607

Malignant glioma, which is characterized by diffuse infiltration into the normal brain parenchyma, is the most aggressive primary brain tumor with dismal prognosis. Over the past 40 years, the median survival has only slightly improved. Therefore, new therapeutic modalities must be developed. In the 1990s, suicide gene therapy began attracting attention for the treatment of malignant glioma. Some clinical trials used a viral vector for suicide gene transduction; however, it was found that viral vectors cannot cover the large invaded area of glioma cells. Interest in this therapy was recently revived because some types of stem cells possess a tumor-tropic migratory capacity, which can be used as cellular delivery vehicles. Immortalized, clonal neural stem cell (NSC) line has been used for patients with recurrent high-grade glioma, which showed safety and efficacy. Embryonic and induced pluripotent stem cells may be considered as sources of NSC because NSC is difficult to harvest, and ethical issues have been raised. Mesenchymal stem cells are alternative candidates for cellular vehicle and are easily harvested from the bone marrow. In addition, a new type of nonlytic, amphotropic retroviral replicating vector encoding suicide gene has shown efficacy in patients with recurrent high-grade glioma in a clinical trial. This replicating viral capacity is another possible candidate as delivery vehicle to tackle gliomas. Herein, we review the concept of suicide gene therapy, as well as recent progress in preclinical and clinical studies in this field.

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Effect of Gravity on Brain Structure as Indicated on Upright Computed Tomography

Yokoyama Y, Yamada Y, Kosugi K, Yamda M, Narita K, Nakahara T, Fujiwara H, Toda M, Jinzaki M

Scientific Reports (Scientific Reports) 11 ( 1 ) 392 2021.01

Research paper (scientific journal), Joint Work, Accepted

We aimed to use upright computed tomography (CT) to depict posture-related changes in the brain tissue under normal gravity. Thirty-two asymptomatic volunteers underwent upright CT in the sitting position and conventional CT in the supine position on the same day. We compared the shift of the pineal body, cerebellar tonsil, the length of pituitary stalk, optic nerve sheath area and perimeter (ONSA and ONSP, respectively), and lateral ventricular volume between the supine and sitting positions. We also compared shape changes of the cerebrospinal fluid (CSF) spaces at different sites between both positions. In the sitting position, the pineal body shifted 0.68 ± 0.27 mm in the ventral direction and 0.76 ± 0.24 mm in the caudal direction, the length of pituitary stalk decreased by 1.23 ± 0.71 mm, the cerebellar tonsil descended by 2.10 ± 0.86 mm, the right ONSA decreased by 15.21 ± 6.54%, the left ONSA decreased by 15.30 ± 7.37%, the right ONSP decreased by 8.52 ± 3.91%, the left ONSP decreased by 8.20 ± 4.38%, and the lateral ventricular volume decreased by 5.07 ± 3.24% (all P < 0.001). We also observed changes in the shape of CSF spaces with changes in posture. We concluded that the intracranial structure of healthy subjects and volume of ventricles changed according to posture on Earth.

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Cystic Dumbbell-shaped C1 Schwannoma with intracranial extension and hydrocephalus: a case report

Matsui Y, Fukumura M, Toda M

World Neurosurg 148 24 - 28 2021.01

Research paper (scientific journal), Joint Work

Background: Schwannomas at the craniocervical junction commonly originate from the lower cranial nerves or C1 and C2 nerves. To date, very few cases of C1 schwannomas have been described in the literature, and the majority involve either the intra- or the extradural compartment, but not both. To our knowledge, this report documents the first case of a dumbbell-shaped C1 schwannoma that encompassed both intra- and extradural compartments and was accompanied by hydrocephalus. Case Description: The patient was admitted to our hospital, where magnetic resonance imaging revealed a tumor at the craniocervical junction, extending from the C1 level of the right first cervical vertebra into the cerebellopontine angle with 2 giant cysts. We removed the tumor by performing a midline posterior craniectomy and cervical laminectomy. Intraoperatively, the tumor was found to originate from the right C1 posterior root. The pathological diagnosis was of a schwannoma. The patient was subsequently discharged without any neurologic deficits. Conclusions: To our knowledge, we present the first case of a dumbbell-shaped C1 schwannoma with intracranial extensions and accompanying hydrocephalus. The tumor had spread inside and outside the dura, but was safely removed. Our findings in this case emphasize that to achieve safe resection, detailed case-specific preoperative consideration is essential.

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A case of moyamoya disease symptomatized early after nivolumab initiation – Possible association between immune checkpoint inhibitors and moyamoya disease

Takahashi S., Matsui Y., Kubo H., Toda M.

Clinical Neurology and Neurosurgery (Clinical Neurology and Neurosurgery) 200 2021.01

ISSN 03038467

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Orthostatic Enlargement of a Supracerebellar　Arachnoid Cyst with Cerebellar Descent Visualized by Upright Computed Tomography

Yoshida K, Toda M, Yamada Y, Yamada M, Yokoyama Y, Fujiwara H, Kosugi K, Sasaki H, Jinzaki M

World Neurosurgery (World Neurosurgery) 145 256 - 259 2021.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 18788750

Background: Posterior fossa arachnoid cysts are often asymptomatic, but can rarely cause postural headache, the mechanism of which remains unknown. Case Description: We present a 40-year-old woman with an asymptomatic supracerebellar arachnoid cyst. Upright computed tomography (CT) showed enlargement of the arachnoid cyst and caudal descent of the cerebellum compared with supine CT with narrowing of the craniocervical junction cerebrospinal fluid space. Conclusions: This finding aids in understanding the association of posterior fossa arachnoid cysts with orthostatic headache. Clinicians should be aware of possible posture-related changes in intracranial structures.

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Pterygovaginal artery as a target of embolization before endoscopic skull base surgery

Yoshida K., Akiyama T., Raz E., Kamamoto D., Ozawa H., Toda M.

Neuroradiology Journal (Neuroradiology Journal) 2021

ISSN 19714009

Background: The pterygovaginal artery (PtVA), a recurrent branch of the internal maxillary artery (IMA), can be a feeder of skull base tumors. Preoperative embolization can help endoscopic resection of hypervascular lesions, which is performed under a narrow surgical space with restricted instrumental maneuverability. Methods: We performed preoperative embolization in five cases with hypervascular skull base lesions supplied by the PtVA, four of which were resected via endoscopic endonasal approach. In two cases, selective PtVA embolization through the distal IMA was successfully conducted. Results: In all the cases, intraoperative bleeding during endoscopic resection was easily controlled. The medial and lateral origins of the PtVA from the IMA were demonstrated by cone-beam CT images reconstructed from three-dimensional rotational angiography, and anastomoses around the eustachian tube and soft palate were visualized by superselective angiography. Conclusions: The PtVA embolization can be an effective strategy before endoscopic skull base tumor resection. When embolizing through the PtVA, clinicians should be aware of its anatomical variations and dangerous anastomoses. Understanding the surrounding angioarchitecture by angiographic techniques helps ensure safe embolization.

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うつ病への脳深部刺激（DBS）療法　脳外科医と精神科医の視点から

高宮彰紘、福村麻里子、小杉健三、戸田正博、三村　將

精神医学 63 ( 12 ) 1825 - 1832 2021

Research paper (scientific journal), Joint Work, Last author, ISSN 04881281

Quiescent and activated fibroblasts in lateral ventricular meningioma with a dura-like membrane

Sato M, Tamura R, Morimoto Y, Ohishi Y, Yoshida K, Toda M

World Neurosurg (World Neurosurgery) S1878-8750(20)32591-2 ( 20 ) 32591 - 32592 2020.12

Research paper (scientific journal), Joint Work, Accepted, ISSN 18788750

Background: Lateral ventricular meningioma (LVM) is a rare entity, accounting for 0.5%–5% of all intracranial meningiomas. This type of meningioma arises from meningothelial inclusion bodies in the tela choroidea and/or mesenchymal stroma of the choroid plexus. Although not yet fully characterized, a membranous structure is frequently observed around LVMs. This study analyzed quiescent and activated fibroblast phenotypes in LVMs with focus on the relationship between tumor growth and development of the membranous structure. Methods: This retrospective study analyzed 9 LVM cases for which gross total removal was achieved. Expression of the ependymal cell marker (Forkhead Box J1 [FoxJ1]) was histopathologically evaluated. The distribution of quiescent and activated fibroblasts was also analyzed using anti-fibroblast-specific protein-1 (FSP1)/S100A4 antibody and anti-α-smooth muscle actin (αSMA) antibody, respectively. The control group was 5 cases with primary convexity meningioma for which Simpson grade I removal was achieved. Results: Small LVMs (≤30 mm) were covered by a FoxJ1-positive(+) ependymal cell monolayer; no αSMA(+) cells were detected in the tumor; and a thick membrane capsule was not observed. None of the convexity meningiomas showed FoxJ1(+) cells. Large LVMs (>30 mm) had thick membrane capsules without an ependymal cell monolayer, which resembled dura mater. The FSP1/S100A4(+) and αSM(+) cells were clearly concentrated in the peripheral area just below the thick dura mater-like membrane capsules. Conclusions: This study found an association between activated fibroblasts and dura mater–like membrane capsules in LVMs. The characteristics of membranous structure in LVMs may differ depending on tumor size.

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Endoscopic Endonasal Management of Pterygopalatine Fossa Tumors

Ozawa H, Sekimizu M, Saito S, Shintaro Nakamura S, Mikoshiba T, Toda M and Ogawa K

The Journal of Craniofacial Surgery Epub ahe 2020.11

Research paper (scientific journal), Joint Work, Accepted

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Prognostic significance of preoperative neutrophil-to-lymphocyte ratio in patients with meningiomas

Kuranari Y, Tamura R, Tsuda N, Kosugi K, Morimoto Y, Yoshida K, Toda M

Frontiers in Oncology (Frontiers in Oncology) Epub ahe 2020.11

Research paper (scientific journal), Joint Work, Accepted

Background: Meningiomas are the most common benign intracranial tumors. However, even WHO grade I meningiomas occasionally show local tumor recurrence. Prognostic factors for meningiomas have not been fully established. Neutrophil-to-lymphocyte ratio (NLR) has been reported as a prognostic factor for several solid tumors. The prognostic value of NLR in meningiomas has been analyzed in few studies. Materials and Methods: This retrospective study included 160 patients who underwent surgery for meningiomas between October 2010 and September 2017. We analyzed the associations between patients’ clinical data (sex, age, primary/recurrent, WHO grade, extent of removal, tumor location, peritumoral brain edema, and preoperative laboratory data) and clinical outcomes, including recurrence and progression-free survival (PFS). Results: Forty-four meningiomas recurred within the follow-up period of 3.8 years. WHO grade II, III, subtotal removal, history of recurrence, Ki-67 labeling index ≥3.0, and preoperative NLR value ≥2.6 were significantly associated with shorter PFS (P < 0.001, < 0.001, 0.002, < 0.001, and 0.015, respectively). Furthermore, NLR ≥ 2.6 was also significantly associated with shorter PFS in a subgroup analysis of WHO grade I meningiomas (P = 0.003). In univariate and multivariate analyses, NLR ≥2.6 remained as a significant predictive factor for shorter PFS in patients with meningioma (P = 0.014). Conclusions: NLR may be a cost-effective and novel preoperatively usable biomarker in patients with meningiomas.

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Historic Overview of Genetic Engineering Technologies for Human Gene Therapy

Tamura R, Toda M

Neurol Med Chir(Tokyo) (Neurologia Medico-Chirurgica) 60 ( 10 ) 483 - 491 2020.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 04708105

The concepts of gene therapy were initially introduced during the 1960s. Since the early 1990s, more than 1900 clinical trials have been conducted for the treatment of genetic diseases and cancers mainly using viral vectors. Although a variety of methods have also been performed for the treatment of malignant gliomas, it has been difficult to target invasive glioma cells. To overcome this problem, immortalized neural stem cell (NSC) and a nonlytic, amphotropic retroviral replicating vector (RRV) have attracted attention for gene delivery to invasive glioma. Recently, genome editing technology targeting insertions at site-specific locations has advanced; in particular, the clustered regularly interspaced palindromic repeats/CRISPR-associated-9 (CRISPR/ Cas9) has been developed. Since 2015, more than 30 clinical trials have been conducted using genome editing technologies, and the results have shown the potential to achieve positive patient outcomes. Gene therapy using CRISPR technologies for the treatment of a wide range of diseases is expected to continuously advance well into the future.

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Targeted Embolisation for Coexisting Conus Medullaris Arteriovenous Malfomation and Cauda Equina Arteriovenous Fistulas with a Varix on a Shared Drainer

Yoshida K, Niimi Y, Kamamoto D, Fukumura M, Imai R, Nagoshi N, Akiyama T

British Journal of Neurosurgery 2020.10

Research paper (scientific journal), Joint Work, Accepted

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Posture-induced changes in the vessels of the head and neck: evaluation using conventional supine CT and upright CT

Kosugi K, Yamada Y, Ymada M, Yokoyama Y, Fujiwara H, Yoshida Ke, Yoshida Ka, Toda M,　Jinzaki M

Scientific Reports (Scientific Reports) 10 ( 1 ) 2020.10

Research paper (scientific journal), Joint Work, Accepted

Since the venous system is affected by gravity, upright computed tomography (CT) in addition to conventional supine CT has great potential for evaluating postural changes in the venous system. We evaluated the morphological differences in the head and neck vessels by performing a contrast CT study in both the supine and the sitting positions. In this study, the 20 included participants (10 men and 10 women) were healthy adults aged 30 to 55 years. The cross-sectional area of the cervical vessels, craniocervical junction veins, and intracranial vessels were obtained quantitatively. Venous sinuses and venous plexuses that were difficult to measure were evaluated qualitatively. The average change in areas from a supine to an upright posture was − 77.87 ± 15.99% (P < 0.0001) in the right internal jugular vein (IJV), − 69.42 ± 23.15% (P < 0.0001) in the left IJV, − 61.52 ± 12.81% (P < 0.0001) in the right external jugular vein (EJV), and − 58.91 ± 17.37% (P < 0.0001) in the left EJV. In contrast, the change in the anterior condylar vein (ACV) from a supine to an upright posture was approximately + 144% (P < 0.005) on the right side and + 110% (P < 0.05) on the left side. In addition, according to the qualitative analysis, the posterior venous structures including the anterior condylar confluence (ACC) of the craniocervical junction became more prominent in an upright posture. Despite these changes, the intracranial vessels showed almost no change between postures. From a supine to an upright position, the IJVs and EJVs above the heart collapsed, and venous channels including the ACCs and ACVs opened, switching the main cerebral venous drainage from the IJVs to the vertebral venous system. Upright head CT angiography can be useful for investigating physiological and pathophysiological hemodynamics of the venous system accompanying postural changes.

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Pros and Cons of the Exoscope for Otologic Surgery

Kanzaki S, Takahashi S, Toda M, Yoshida K, Ogawa K.

Surgical Innovation (Surgical Innovation) 2020.09

Research paper (scientific journal), Joint Work, Accepted, ISSN 15533506

Introduction. There are a few discussions regarding usefulness of an exoscope in otologic surgery compared to a traditional microscope. Objective. The pros and cons of using a newly developed exoscope (ORBEYE™) during microotologic surgery were evaluated. Methods. The usefulness of the ORBEYE™ exoscope was retrospectively assessed in 6 otologic surgeries by 8 surgeons postoperatively. A questionnaire comprising 20 questions was designed and used for evaluation. Results. All the otologic surgeons agreed that the exoscope is useful as an educational tool; the exoscope had the highest score in the questionnaire (average: 4.75). The question “Will the ORBEYE exoscope replace the conventional tympanoplasty or stapes surgery?” had the lowest score (average: 3.13). Conclusions. The quality of the images and movies in the exoscope was considered to be high and improved; therefore, the exoscope was considered as a useful educational tool in otologic surgery. Similar to otologic endoscopic surgery, all the members such as the operator and assistants could head up and share 1 image. TM

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Endoscopic endonasal transinfraturbinate approach with nasoseptal window for removal of the pterygopalatine fossa tumor

Yamada H, Toda M, Abiko T, Ozawa H, Ogawa K, Yoshida K

J Craniofac Surg 2020.09

Research paper (scientific journal), Joint Work, Accepted

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A pilot study of the adverse events caused by the combined use of bevacizumab and vascular endothelial growth factor receptor-targeted vaccination for patients with a malignant glioma

Tamura R., Morimoto Y., Sato M., Hikichi T., Yoshida K., Toda M.

Vaccines (Vaccines) 8 ( 3 ) 1 - 10 2020.09

Anti-angiogenic therapy, targeting vascular endothelial growth factor (VEGF)-A/VEGF receptors (VEGFRs), is beneficial for tumor growth prevention in a malignant glioma. A simultaneous blockade using both bevacizumab (Bev), which targets circulating VEGF-A, and a multi-kinase inhibitor on VEGFRs was more effective for advanced solid cancers, including melanoma and renal cell carcinoma. However, previous clinical trials demonstrated a high adverse event rate. Additionally, no studies previously assessed treatment efficacy and safety using both VEGF-A and VEGFR-targeted agents for malignant gliomas. We had conducted clinical trials investigating VEGFRs peptide vaccination in patients with malignant gliomas, in which the treatment exhibited safety and yielded therapeutic effects in some patients. The combined use of Bev and VEGFRs vaccination may enhance the anti-tumor effect in malignant gliomas. In this pilot study, the adverse event profile in patients treated with Bev after the vaccination was investigated to establish this treatment strategy, in comparison to those treated with Bev collected from the published data or treated with the vaccination alone. In our previous clinical studies on patients with malignant gliomas, Bev was administered to 13 patients after VEGFRs vaccinations. One patient had a Grade 4 pulmonary embolism. Two patients had Grade 2 cerebral infarctions. There were no significant differences in the adverse event rates among patients treated with Bev, with the vaccination, or with Bev after the vaccination. Although careful observation is imperative for patients after this combination treatment strategy, VEGFRs-targeted vaccination may coexist with Bev for malignant gliomas.

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Current understanding of lymphatic vessels in the central nervous system

Tamura R., Yoshida K., Toda M.

Neurosurgical Review (Neurosurgical Review) 43 ( 4 ) 1055 - 1064 2020.08

ISSN 03445607

Lymphangiogenesis is associated with some pathological conditions such as inflammation, tissue repair, and tumor growth. Recently, a paradigm shift occurred following the discovery of meningeal lymphatic structures in the human central nervous system (CNS); these structures may be a key drainage route for cerebrospinal fluid (CSF) into the peripheral blood and may also contribute to inflammatory reaction and immune surveillance of the CNS. Lymphatic vessels located along the dural sinuses absorb CSF from the adjacent subarachnoid space and brain interstitial fluid via the glymphatic system, which is composed of aquaporin-4 water channels expressed on perivascular astrocytic end-feet membranes. Magnetic resonance imaging (MRI) clearly visualized these lymphatic vessels in the human dura mater. The conception of some neurological disorders, such as multiple sclerosis and Alzheimer’s disease, has been changed by this paradigm shift. Meningeal lymphatic vessels could be a promising therapeutic target for the prevention of neurological disorders. However, the involvement of meningeal lymphatic vessels in the pathophysiology has not been fully elucidated and is the subject of future investigations. In this article, to understand the involvement of meningeal lymphatic vessels in neurological disorders, we review the differences between lymphangiogenesis in the CNS and in other tissues during both developmental and adulthood stages, and pathological conditions that may be associated with meningeal lymphatic vessels in the CNS.

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Sinking Skin Flap Syndrome Visualized by Upright Computed Tomography

Yoshida K, Toda M, Yamada Y, Yamada M, Yokoyama Y, Fujiwara H, Kosugi K, Fukumura M, Koike K, Takahashi S, Yoshida K, Jinzaki M

Acta Neurochir (Wien) (Acta Neurochirurgica) 162 ( 8 ) 1825 - 1828 2020.08

Research paper (scientific journal), Joint Work, Accepted, ISSN 00016268

Sinking skin flap syndrome is a craniectomy complication characterized by new neurological dysfunction that typically worsens in the upright position and improves after cranioplasty. We present a 33-year-old man who experienced hemiparesis in the upright position after craniectomy. Upright computed tomography (CT) before cranioplasty showed a remarkable shift of the brain compared to supine CT. After cranioplasty, both symptoms and brain shift on CT resolved. Upright CT enables detection and objective evaluation of paradoxical herniation and midline shift that is not obvious on supine imaging modalities. Clinicians need to be aware of positional brain shift in postcraniectomy patients.

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Endoscopic endonasal removal of a pediatric paranasal ossifying fibroma using preoperative embolization

Saito S., Ozawa H., Ikari Y., Nakahara N., Ito F., Sekimizu M., Kameyama K., Akiyama T., Toda M., Ogawa K.

Otolaryngology Case Reports (Otolaryngology Case Reports) 14 2020.03

Background: Ossifying fibroma arising in the sinonasal tract is rare. Its treatment includes complete resection; however, this can be challenging to perform due to the well-vascularized nature of the fibroma. Some surgical techniques can control intraoperative hemorrhage; however, to date, no reports have assessed the use of preoperative embolization. Methods: We report a case of a child with ossifying fibroma arising from the ethmoid sinus, which was resected by endoscopic surgery using preoperative transarterial embolization. Conclusions: Embolization was effective in decreasing intraoperative hemorrhage. No complications related to the procedure or operation were encountered. Preoperative embolization should be considered for better control of the bleeding that occurs in ossifying fibromas, similar to that in other well-vascularized tumors.

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A case of moyamoya disease symptomatized early after nivolumab initiation - Possible association between immune checkpoint inhibitors and moyamoya disease

Ozawa H, Sekimizu M, Saito S, Nakamura S, Mikoshiba T, Toda M, Ogawa K

Clin Neurol Neurourg 2020.01

Research paper (scientific journal), Joint Work, Accepted

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Cerebrospinal fluid leakage due to nasoseptal flap partial necrosis: a pitfall for skull base reconstruction of endoscopic endonasal surgery

Yamada H, Toda M, Fukumura M, Ozawa H, Ogawa K, Yoshida K

Surg Neurol Int (Surgical Neurology International) 11 ( 121 ) 2020

Research paper (scientific journal), Joint Work

Background: Vascularized nasoseptal flaps allow for the reconstruction of large dural defects and have remarkably reduced the incidence of postoperative complications during endoscopic endonasal skull base surgery. Nevertheless, some complications related to nasoseptal flap have been reported. Flap necrosis is a rare, but serious issue is associated with meningitis and cerebrospinal fluid (CSF) leak. Case Description: We performed endoscopic endonasal removal of the tuberculum sella meningioma in a 39-year-old woman with a history of Turner syndrome using abdominal fat, fascia, and a vascularized nasoseptal flap for dural and skull base defect reconstruction. After surgery, she developed CSF leak, and reoperation revealed partial necrosis of the septal flap that caused leakage. At this time, with a concern that removal of the necrotic part may lead to the insufficient size of the flap, we filled the gap tightly with fat pieces. However, the CSF leak recurred, and thus, we performed debridement of the necrotic region and reformed the multilayered reconstruction, following which she no longer experienced CSF leakage. Conclusion: Our case suggested that partial rather than total flap necrosis could occur, possibly due to variances of vascular anatomy, leading to focal ischemia. Debridement of the necrotic region may be an important solution for recurrent cerebrospinal leakage secondary to partial necrosis of a nasoseptal flap.

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Difference in the hypoxic immunosuppressive microenvironment of patients with neurofibromatosis type 2 schwannomas and sporadic schwannomas.

Tamura R, Morimoto Y, Sato M, Kuranari Y, Oishi Y, Kosugi K, Yoshida K, Toda M

J Neurooncol (Journal of Neuro-Oncology) 146 ( 2 ) 265 - 273 2020

Research paper (scientific journal), Joint Work, ISSN 0167594X

Background: Neurofibromatosis type 2 (NF2) patients uniformly develop multiple schwannomas. The tumor-microenvironment (TME) is associated with hypoxia and consists of immunosuppressive cells, including regulatory T cells (Tregs) and tumor-associated macrophages (TAMs). The hypoxic TME of NF2 schwannomas remains unclear. In addition, no comparative study has investigated immunosuppressive cells in NF2 and sporadic schwannomas. Methods: In 22 NF2 and 21 sporadic schwannomas, we analyzed the immunohistochemistry for Ki-67, hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor receptor 1 (VEGFR1) and VEGFR2, platelet derived growth factor receptor-beta (PDGFR-β), programmed cell death-1 (PD-1)/ programmed cell death ligand-1 (PD-L1), Foxp3, CD163, CD3, and CD8 to assess the immunosuppressive TME. Results: Most vessels in sporadic schwannomas exhibited slight or negative VEGFR1 and 2 expressions with pericytes coverage. In contrast, large vessels in NF2 schwannomas exhibited strong VEGFR1 and 2 expressions without pericytes. The number of CD3 , CD8 , and CD163 cells was significantly higher in NF2 schwannomas than in sporadic ones. The expression of PD-L1 and nestin positive cell ratio was higher in NF2 schwannomas than that in sporadic ones. The number of CD163 cells, nestin positive cell ratio, and HIF-1α expression were significantly associated with shorter progression-free survival in NF2 schwannomas. Conclusions: This study presents the clinicopathological features of the differences in immunosuppressive cells and the expression of immune checkpoint molecules between NF2 and sporadic schwannomas. Hypoxic TME was first detected in NF2-schwannomas, which was associated with the tumor progression. + + + +

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Prediction of postoperative recurrence of chronic subdural hematoma using quantitative volumetric analysis in conjunction with computed tomography texture analysis.

Kanazawa T, Takahashi S, Minami Y, Jinzaki M, Toda M, Yoshida K

J Clin Neurosci (Journal of Clinical Neuroscience) 72 270 - 276 2020

Research paper (scientific journal), Joint Work, ISSN 09675868

Chronic subdural hematoma (CSDH) is a common disease in older individuals with a substantial rate of recurrence. The mechanism of CSDH recurrence remains unclear. This study aimed to detect imaging parameters that could indicate the risk for CSDH recurrence by using quantitative volumetric analysis and computed tomography (CT) texture analysis (CTTA). Clinical and imaging parameters were retrospectively investigated in 147 newly diagnosed CSDH lesions in 114 patients surgically treated at the Keio University Hospital during a 6-year period. For CT images, quantitative volumetric and texture analyses were performed. Hematoma volume, postoperative air volume, hematoma density, and texture parameters including kurtosis, skewness, and entropy were evaluated and compared with CSDH recurrence rate. Data were statistically evaluated, and a difference of p < 0.05 was considered significant. Reoperation for CSDH recurrence was required in 27 sides (18.4%) of 26 patients. Multivariate analysis showed that postoperative hematoma volume and postoperative hematoma density were independent risk factors for symptomatic CSDH recurrence that required reoperation. Postoperative hematoma volume, postoperative significant residual air, and postoperative hematoma density were also identified as independent risk factors for potential CSDH recurrence. Preoperative hematoma entropy was prone to be associated with both symptomatic and potential CSDH recurrence in univariate analysis, but not in multivariate analysis because of confounding factors. Quantitative volumetric analysis and CTTA could aid in distinguishing individuals at risk for CSDH recurrence.

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Efficacy of a topical gelatin-thrombin hemostatic matrix, FLOSEAL®, in intracranial tumor resection.

Kamamoto D, Kanazawa T, Ishihara E, Yanagisawa K, Tomita H, Ueda R, Jinzaki M, Yoshida K, Toda M

Surgical Neurology International (Surgical Neurology International) 72 ( 16 ) 270 - 276 2020

Research paper (scientific journal), Joint Work

Background: Hemostasis plays an important role in safe brain tumor resection and also reduces the risk for surgical complications. This study aimed to evaluate the efficacy of FLOSEAL®, a topical hemostatic agent that contains thrombin and gelatin granules, in brain tumor resections. Methods: We evaluated the hemostatic effect of FLOSEAL by scoring the intensity of bleeding from 1 (mild) to 4 (life threatening). We assessed the rate of success of hemostasis with 100 patients who underwent intracranial tumor resection. We also investigated the duration of the operation, the amount of intra- and postoperative bleeding, the number of hospital stays, and adverse events in patients who used FLOSEAL compared with those who did not use FLOSEAL. Results: FLOSEAL was applied to a total of 109 bleeding areas in 100 patients. A total of 95 bleeding areas had a score of 1 and 91 (96%) showed successful hemostasis. Thirteen bleeding areas scored 2 and 8 (62%) showed hemostasis with the first application of FLOSEAL. The second application was attempted with five bleeding areas and four showed hemostasis. About 94% (103/109 areas) of bleeding points successfully achieved hemostasis by FLOSEAL. Moreover, FLOSEAL significantly decreased the amount of intraoperative bleeding and postoperative bleeding as assessed with computed tomography on 1 day postoperatively compared with no use of FLOSEAL. There were no adverse events related to FLOSEAL use. Conclusion: Our results indicate that FLOSEAL is a reliable, convenient, and safe topical hemostatic agent for intracranial tumor resection.

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Surgical outcomes of anterior cerebellopontine angle meningiomas using the anterior transpetrosal approach compared with the lateral suboccipital approach.

Hassaan SA, Tamura R, Morimoto Y, Kosugi K, Mahmoud M, Abokerasha A, Moussa A, Toda M, Yoshida K

Acta Neurochir (Wien) (Acta Neurochirurgica) 162 ( 6 ) 1243 - 1248 2020

Research paper (scientific journal), Joint Work, ISSN 00016268

Background: Anterior transpetrosal approach (ATPA) and lateral suboccipital approach (LSO) are the major surgical approaches for cerebellopontine angle (CPA) meningiomas. Particularly, anterior CPA meningiomas are challenging lesions to be treated surgically. To date, only a few studies have directly compared the outcomes of both approaches focusing on the anterior CPA meningiomas. Methods: For the comparative analysis, anterior CPA meningiomas that were eligible for both APTA and LSO were collected in our hospital from April 2005 to March 2017. Anterior CPA meningiomas targeted for this study were defined as follows: (1) without cavernous sinus, clivus, and middle cranial fossa extension, (2) the posterior edge is 1 cm behind the posterior wall of the internal auditory canal, and (3) the inferior edge is above the jugular tuberculum. Based on these criteria, the operative outcomes of 17 patients and 13 patients who were operated via ATPA and LSO were evaluated. Results: The complication rate of the LSO group was significantly higher than that of the ATPA group (30.7% vs. 0%, p = 0.033). The removal rate did not differ between the ATPA and LSO groups (97.35% vs. 99.23%, p = 0.12). The operative time was significantly shorter in the LSO group than in the ATPA group (304.3 min vs. 405.8 min, p = 0.036). Conclusions: Although the LSO is more widely used for CPA meningiomas, ATPA is also considered for these anterior CPA meningiomas.

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Quantitative assessment and clinical relevance of VEGFRs-positive tumor cells in refractory brain tumors.

Tamura R, Sato M, Morimoto Y, Ohara K, Kosugi K, Oishi Y, Kuranari Y, Murase M, Yoshida K, Toda M

Exp Mol Pathol (Experimental and Molecular Pathology) 114 2020

Research paper (scientific journal), Joint Work, ISSN 00144800

Vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR)1 and 2 signaling is a potent activator of tumor angiogenesis. Although the expressions of VEGFR1 and VEGFR2 were initially thought to be limited to the endothelial cells, it is now known that both the receptors are expressed in tumor cells. This is the first study wherein VEGFRs-positive tumor cells are quantitatively evaluated for brain tumors with upregulated VEGF/VEGFR signaling. The percentage of VEGFRs-positive tumor cells was quantitatively evaluated in various brain tumors (10 glioblastomas, 22 neurofibromatosis type 2 [NF2]-related schwannomas, 21 sporadic schwannomas, 27 chordomas, 36 meningiomas, 29 hemangioblastomas, 11 hemangiopericytoma, and 13 ependymomas) using immunohistochemistry. VEGF-A expression was also analyzed using quantitative real-time polymerase chain reaction. Double immunofluorescence staining using anti-PDGFR-β and anti-CD34 antibody, microvessel density, and vessel diameter were analyzed to evaluate the vascular characteristics. Chordomas demonstrated an extremely higher percentage of VEGFR1 and VEGFR2-positive tumor cells than other tumors. In contrast, meningiomas and hemangiopericytomas showed few VEGFRs-positive tumor cells. The percentage of positive tumor cells in chordomas, hemangioblastomas, and NF2 schwannomas was associated with clinical courses, such as shorter progression free survival, and growth speed. Glioblastomas and NF2 schwannomas showed larger tumor vessels without pericyte coverage. The present study is the first to quantitatively analyze VEGFR1- and VEGFR2- positive tumor cells in various types of refractory brain tumors. This novel parameter significantly correlated with the progressive clinical courses.

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Gene Therapy Using Neural Stem/Progenitor Cells Derived from Human Induced Pluripotent Stem Cells: Visualization of Migration and Bystander Killing Effect.

Tamura R, Miyoshi H, Morimoto Y, Oishi Y, Sampetrean O, Iwasawa C, Mine Y, Saya H, Yoshida K, Okano H, Toda M

Hum Gene Ther (Human Gene Therapy) 31 ( 5-6 ) 352 - 366 2020

Research paper (scientific journal), Joint Work, ISSN 10430342

Glioblastoma is the most aggressive brain tumor characterized by diffuse infiltration into the normal brain parenchyma. Neural stem cells are known to possess the tumor-tropic migratory capacity and thus can be used as cellular vehicles for targeted delivery of therapeutic agents. In the present study, we evaluated the efficacy of herpes simplex virus thymidine kinase (HSV-TK) suicide gene therapy for glioblastoma using neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs). Although transduction of hiPSCs is preferable for a safe and stable supply in the clinical setting, high-level and/or constitutive HSV-TK expression was highly cytotoxic to hiPSCs. To overcome this problem, we used the tetracycline-inducible system to control the expression of HSV-TK. hiPSC-derived NS/PCs expressing HSV-TK were transplanted in an orthotopic xenograft mouse model of human glioblastoma. Glioblastoma cell growth in mice was dramatically inhibited following ganciclovir (GCV) administration. Survival of the mice was significantly prolonged with administration of GCV compared with control groups. Time-lapse imaging of organotypic brain slice cultures first demonstrated the directional migration of NS/PCs toward glioblastoma cells and the bystander killing effect upon GCV treatment. hiPSC-derived NS/PCs with HSV-TK/GCV suicide gene system may have considerable therapeutic potential for the treatment of glioblastoma. Color images are available online.

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Clinical and histopathological analyses of VEGF receptors peptide vaccine in patients with primary glioblastoma - a case series.

Tamura R, Morimoto Y, Kosugi K, Sato M, Oishi Y, Ueda R, Kikuchi R, Nagashima H, Hikichi T, Noji S, Kawakami Y, Sasaki H, Yoshida K, Toda M

BMC Cancer (BMC Cancer) 20 ( 1 ) 196 2020

Research paper (scientific journal), Joint Work

Background: The expression of vascular endothelial growth factor (VEGF)-A/ VAGF receptors (VEGFRs) signaling plays a pivotal role in the tumor angiogenesis and the development of the immunosuppressive tumor microenvironment in glioblastomas. We have previously conducted exploratory clinical studies investigating VEGFRs peptide vaccination with and without multiple glioma oncoantigens in patients with recurrent high-grade gliomas. Recently, an exploratory clinical investigation of VEGFRs peptide vaccination was conducted in patients with progressive neurofibromatosis type 2. Those studies suggested that cytotoxic T lymphocytes (CTLs) induced by the vaccination can directly kill a wide variety of cells associated with tumor growth, including tumor vessels, tumor cells, and immunosuppressive cells expressing VEGFR1 and/or 2. In the present study, synergistic activity of the combination of VEGFRs peptide vaccination with chemotherapy was evaluated. Methods: We performed the first clinical trial to assess VEGFR1 and 2 vaccination along with temozolomide (TMZ) -based chemoradiotherapy for the patients with primary glioblastomas. Furthermore, histopathological changes after the vaccination were evaluated using paired pre- and post- vaccination specimens. Results: The disappearance of radiographically enhanced lesion was observed in 2 patients after the vaccination, including one in which the methylation of the O6-methylguanine-DNA methyltransferase (MGMT) promoter was not observed. The histopathological findings of pre- and post-vaccination specimens demonstrated that tumor vessels showed negative or slight VEGFRs expressions after the vaccination and most endothelial cells were covered with PDGFR-β-positive pericytes. Notably, CTLs induced by VEGFRs peptide vaccination attacked not only tumor vessels but also tumor cells and regulatory T cells expressing VEGFRs even in recurrent tumors. Conclusions: VEGFR1 and 2 vaccination may have a preliminary synergistic effect when administered with TMZ. The limitation of the present study was the paucity of the number of the samples. Further studies involving more patients are warranted to confirm the findings of this study. Trial registration: This study was registered as UMIN000013381 (University Hospital Medical Information Network-Clinical Trial Registry: UMIN-CTR) on 5 March, 2014 and with the Japan Registry of Clinical Trials (jRCT) as jRCTs031180170 on 1 March, 2019.

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Analysis of the superficial middle cerebral vein in sphenoid ridge meningioma using contrast-enhanced dynamic computed tomography angiography.

Murase M, Mizutani K, Kawata K, Fujiwara H, Jinzaki M, Toda M, Yoshida K

Clin Neurol Neurosurg 191:105683, 2020 (Clinical Neurology and Neurosurgery) 191 ( 105683 ) 2020

Research paper (scientific journal), Joint Work, ISSN 03038467

Objective: The superficial middle cerebral vein (SMCV) is of clinical importance because of its contribution to the venous drainage of the superficial part of the cerebrum. Sphenoid ridge meningioma (SRM) grows adjacent to the SMCV and its drainage routes, and is thought to occasionally influence the hemodynamics of the SMCV, although this has seldom been suggested in the literature. We investigated the effect of SRM on the SMCV via blood flow analysis using multi-detector computed tomography. Patients and Methods: Overall, 22 patients with SRM who preoperatively underwent contrast-enhanced dynamic computed tomography at our institution were included in this study. We serially measured the Hounsfield units at each point of the SMCV and its adjacent veins on the side on which the tumor was located. We then obtained a time-density curve for each point via gamma distribution fitting. We determined the time-to-peak at each point by calculating the derivative of the time-density curve function and deduced the direction of blood passing through each vein by comparing the time-to-peak values between several points. Results: In total, 26 SMCVs were measured in 19 out of 22 cases. Of the 26 SMCVs, 16 were patent in the medial portion and contributed to normal venous drainage: 4 of them emptied into the cavernous sinus (CS), and 12 of them into the para-cavernous sinus (ParaCS). Out of the 10 that had their medial portions occluded because of the effects of the tumor, 6 SMCVs mainly drained into the vein of Labbé and/or the vein of Trolard retrogradely. However, in 2 of these, the small medial portions of the SMCVs near the occluded portion were maintained anterogradely by the collateral venous structures. In 4 SMCVs, the blood flow through the collateral veins remained anterograde; this was considered to contribute to normal venous drainage. Conclusion: The SRM is likely to cause occlusion or stenosis in the SMCV and influence its hemodynamics. In cases in which the connection between the SMCV and the CS or the ParaCS has been lost, the SMCV may still be involved in normal venous drainage via the collateral veins in some of those cases. Thus, the contribution of these veins to normal venous drainage in the brain should be analyzed preoperatively in careful detail.

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A Comparative Study Between Traditional Microscopic Surgeries and Endoscopic Endonasal Surgery for Skull Base Chordomas

Oishi Y, Tamura R, Takahashi S, Morimoto Y, Sato M, Horikoshi T, Hassaan S, Yoshida K, Toda M

World Neurosurg (World Neurosurgery) 134 e1099 - e1107 2020

Research paper (scientific journal), Joint Work, ISSN 18788750

Background: Skull base chordomas (SBCs) are rare clinically aggressive neoplasms, developing local recurrences after surgical resection. Although SBCs have traditionally been resected by craniotomy or microscopic transsphenoidal surgery (TSS), the recent development of the endoscopic endonasal approach (EEA) has revolutionized treatment strategies through minimally invasive techniques. This study aimed to evaluate clinical outcomes after traditional microsurgeries or EEAs for SBCs. Methods: The present retrospective study investigated 66 patients with primary SBCs who underwent surgery between 1977 and 2019. Resection was performed via EEA in 17 cases, craniotomy in 23, transoral approach in 8, TSS in 12, staged surgery in 4, and others in 2. The median follow-up period for progression-free survival (PFS) was 19.5 months. Results: There were no significant differences in preoperative tumor volume or resection rate among these approaches. The incidence of postoperative cranial nerve palsy was significantly lower in EEA than that in craniotomy (P < 0.05). Although total resection was observed in 4 cases of EEA expanding into the superior and inferior part of the clivus, no cases of transoral approach or TSS achieved total resection for both parts. No significant difference in PFS was found among these approaches. Multivariate analysis showed that being female and the absence of radiotherapy were significantly associated with shorter PFS (P < 0.05 and P < 0.001, respectively). The resection rate was not associated with PFS. Conclusions: EEA is a less invasive surgical approach for SBCs. The development of surgical instruments and postoperative radiotherapy will further improve patients' outcomes.

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A Novel Flow Dynamics Study of the Intracranial Veins Using Whole Brain Four-Dimensional Computed Tomography Angiography

Mizutani K., Arai N., Toda M., Akiyama T., Fujiwara H., Jinzaki M., Yoshida K.

World Neurosurgery (World Neurosurgery) 131 e176 - e185 2019.11

ISSN 18788750

Background: The flow dynamics of the intracranial venous channels are fundamentally important for understanding intracranial physiology and pathophysiology. However, the method clinically applicable to the evaluation of the flow dynamics of the intracranial venous system has not been well described in the reported data. We have developed a new method to evaluate intracranial venous flow direction and velocity using 4-dimensional (4D) computed tomography angiography (CTA). The aim of the present study was to verify the accuracy and validity of 4D-CTA in a clinical setting. Methods: We retrospectively analyzed 97 veins from 26 patients (16 cases of arteriovenous shunt disease, 9 intracranial tumor cases, and 1 cerebral aneurysm case) who had undergone both 4D-CTA and conventional digital subtraction angiography (DSA). Using 4D-CTA, we analyzed the time-density curve with gamma distribution extrapolation and obtained the direction of the flow and flow velocity of each vein. The direction of the flow in 4D-CTA was also collated with that obtained using conventional DSA to verify the experimental method. Results: The direction of the flow determined by 4D-CTA was consistent with that of conventional DSA in 94.8% of cases. The average venous flow velocity was 64.3 mm/second and 81.8 mm/second, respectively, in the antegrade and retrograde channels affected by arteriovenous shunts. Conclusions: The present flow analysis using 4D-CTA enabled us to evaluate the direction and velocity of intracranial venous flow. Other than some limitations, the presented method is reliable and its potential for application in clinical settings is promising.

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Prognostic Significance of VEGF Receptors Expression on the Tumor Cells in Skull Base Chordoma

Morimoto Y, Tamura R, Ohara K, Kosugi K, Oishi Y, Kuranari Y, Yoshida K, Toda M.

Journal of Neuro-Oncology (Journal of Neuro-Oncology) 144 ( 1 ) 65 - 77 2019.06

Research paper (scientific journal), Joint Work, ISSN 0167594X

Background: Chordoma is a rare refractory neoplasm that arises from the embryological remnants of the notochord, which is incurable using any multimodality therapy. Vascular endothelial growth factor (VEGF) is a potent activator of angiogenesis that is strongly associated with the tumor-immune microenvironment. These factors have not been elucidated for chordomas. Methods: To evaluate the characteristics of vascular and tumor cells in chordoma, we first analyzed the expression of VEGF receptor (VEGFR) 1, VEGFR2, CD34, and Brachyury in a cell line and 54 tumor tissues. Patients with primary skull base chordomas were divided into the following two groups as per the tumor growth rate: patients with slow progression (SP: < 3 mm/year) and those with rapid progression (RP: ≥ 3 mm/year). Thus, the expressions of VEGF-A, VEGFR 1, and VEGFR2 on tumor cells; tumor infiltrative immune cells, including regulatory T cells (Tregs) and tumor-associated macrophages (TAMs); and immune-checkpoint molecules (PD-1/PD-L1) were analyzed with the clinical courses, especially in a comparison between the two groups. Results: In chordomas, both VEGFR1 and VEGFR2 were strongly expressed not only on vascular endothelial cells, but also on tumor cells. The recurrent cases showed significantly higher VEGFR1 expressions on tumor cells than the primary cases. The expression of VEGF-A was significantly higher in RP than that in SP group. The numbers of CD163+ TAMs and Foxp3+ Tregs were higher in RP than that in SP group. Conclusions: Expression of VEGFR1 and VEGFR2 on tumor cells and immunosuppressive tumor-microenvironment were related to tumor growth in patients with chordomas.

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Immunological and vascular characteristics in cavernous sinus meningioma.

Kosugi K, Tamura R, Ohara K, Morimoto Y, Kuranari Y, Oishi Y, Yoshida K, Toda M

Journal of Clinical Neuroscience (Journal of Clinical Neuroscience) 67 198 - 203 2019.06

Research paper (scientific journal), Joint Work, ISSN 09675868

Objectives: It is difficult to treat cavernous sinus (CS) meningiomas because of their complex vascular and neurological structures. Recently, immunotherapy has become an attractive therapeutic modality, but the role of tumor immune microenvironment is yet to be investigated for CS meningiomas. In the current study, these molecular and histopathological characteristics were examined in CS meningiomas. Methods: The present study used twenty-eight meningioma tissues arising in two different locations (8 CS and 20 convexity meningiomas). Immunohistochemical analyses were performed with CD3, CD4, CD8, Foxp3, CD163, PDGFR-β, VEGF receptors 1 & 2 (VEGFR-1, VEGFR-2), VEGF-A and HIF-1α. Quantitative polymerase chain reaction (qPCR) was performed to assess the expression of Foxp3, VEGF-A, CD163, VEGFRs-1 & 2 and HIF-1α. Results: The numbers of different tumor-infiltrating immune cells, such as immunosuppressive cells, were significantly lower in CS meningiomas compared with convexity meningiomas. Analysis of the vascular characteristics showed the vessels in the CS meningiomas were covered with PDGFR-β-positive pericytes and were negative or had only very low amounts of VEGFR-1 and VEGFR-2. However, most vessels in convexity meningiomas showed high VEGFRs expression and were not covered with pericytes. Immunohistochemical and qPCR analyses revealed that the expression of HIF-1α, VEGF-A and VEGFRs-1 & 2 was lower in CS meningiomas. Conclusion: Fewer immunocompetent cells were observed in CS meningiomas compared with convexity meningiomas. Lower expression of VEGF-A, VEGFRs-1 and 2, and the vascular structure may contribute to this specific immune microenvironment.

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Characteristics intracranial epidermoid cyst between two hospital from developed vs developing institution and literature review

Sutiono A.B., Sidbutar R, Pareira E.S., Toda M, Yoshida K

Interdisciplinary Neurosurgery (Interdisciplinary Neurosurgery: Advanced Techniques and Case Management) 18 2019.06

Joint Work

Introduction: Intracranial epidermoid tumors are slow-growing lesions, which may recur after incomplete resection (surgery), but may do so over many years. These slow growing benign tumors encase and surround nerves and arteries rather than displacing them and the treatment of choice is radical surgery. Therefore the clinical symptoms are varies. The incidence of intracranial epidermoids is between 0.3% and 1.8% of all brain tumors. Whether the characteristics of tumor are related with culture of clinical neurologic in different developed and developing institution has not been discussed yet. Methods: Between 2015 until 2017, we collected data from two institutions, Keio University hospital Tokyo Japan and Hasan Sadikin Hospital Padjadjaran University Bandung Indonesia. We collect 16 patients from Keio University hospital (KUH) and 10 patients from Hasan Sadikin hospital (HSH). Results: In which the 11 cases is located in infratentorial and 5 cases were in supratentorial region at KUH. Meanwhile in HSH, we found that 10 patients were in infratentorial. The characteristic of cranial nerve palsy and/or neurological deficits are mainly similar in infratentorial region whether from KUH or HSH, including supratentorial epidermoid are also similar. At KUH, the location of epidermoid is located in the CPA (cerebellopontine angle) in 8 patients, 3 in suprasellar region, 1 in Meckel's cave, 1 in 4th ventricle, 1 in medulla, 1 in petroclival and 1 in occipital lobe. In HSH, the lesions are located in infratentorial in which 5 patient in CPA, 4 in petroclival region and 1 case in Meckel's cave. In infratentorial lesion the CNs (cranial nerves) palsy were found in CN IV, V, VI, VII, VIII, and none in IX, X, XI, XII. In supratentorial lesion the chief complaint was mainly headache. Conclusion: The epidermoid of the brain are mostly located in the infratentorial region rather than in supratentorial. The CNs deficit are commonly arose in infratentorial lesion meanwhile the supratentorial region symptom is headache. It is reasonable if the patient came with infratentorial multiple CNs palsy to be suspicious for epidermoid benign tumor in the intracranial. Those characteristics are found in both developed and developing hospitals.

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Bridging vein and tentorial sinus in the subtemporal corridor during the anterior transpetrosal approach

Shibao S., Toda M., Fujiwara H., Jinzaki M., Yoshida K.

Acta Neurochirurgica (Acta Neurochirurgica) 161 ( 4 ) 821 - 829 2019.04

ISSN 00016268

© 2019, Springer-Verlag GmbH Austria, part of Springer Nature. Background: The bridging vein (BV) and the tentorial sinus (TenS) are important venous structures in neurological surgery. These venous structures during the anterior transpetrosal approach (ATPA) have not been reported. The objective of this study is to examine the BV and the TenS in the subtemporal corridor during the ATPA and propose a technique to identify the BV preoperatively. Methods: This study included 126 patients treated via the ATPA. The BV and the TenS located in the operative fields were analyzed. Furthermore, in the preoperative evaluation, the cross-sectional shapes of the intradural vein and the interdural sinus were analyzed by curved planar reconstruction (CPR), and the flattening rate was calculated. Flattening rate = (a-b)/a = 1-b/a (a: long radius, b: short radius). Results: Seventeen BVs and 18 TenS were identified. The bridging site was divided into two groups: tentorial and middle fossa. The middle fossa group was divided into three subgroups: cavernous sinus, middle fossa dural sinus, and middle fossa dural adherence. Five isolated TenS were sacrificed and no venous complications were observed. The mean flattening rate was 0.13 in the intradural vein and 0.51 in the interdural sinus, respectively (P = 0.0003). Conclusions: We showed classification of the BV, and preservation of the BV and TenS during the ATPA. Furthermore, we found that the interdural sinus was significantly flatter than the intradural veins. Measuring the flattening rate by CPR may be useful to identify BVs preoperatively.

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Analysis of tumor angiogenesis and immune microenvironment in non-functional pituitary endocrine tumors.

Sato M, Tamura R, Tamura H, Mase T, Kosugi K, Morimoto Y, Yoshida K, Toda M

J.Clin.Med 8 ( 5 ) 2019.03

Research paper (scientific journal), Joint Work

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Endoscopic Endonasal Removal of Large Calcified Pituitary Adenoma: Case Report and Review of the Literature

Murase M., Toda M., Ohara K., Ishihara E., Yoshida K.

World Neurosurgery (World Neurosurgery) 123 239 - 243 2019.03

ISSN 18788750

© 2018 Elsevier Inc. Background: Large calcified intrasellar masses, called pituitary stones, have been reported as calcified pituitary adenomas in the literature. Although relatively rare, calcified pituitary adenomas appear in various formations. Thus, whether the lesion is removable—and, if so, which approach is appropriate—mainly depends on its formation and quality. Case Description: A 46-year-old woman presented with visual loss and amenorrhea. Although computed tomography showed a uniformly calcified sellar tumor, magnetic resonance imaging displayed heterogenous intensity on T2-weighted images and mild gadolinium enhancement, suggesting that the lesion was a mixture of pituitary adenoma and fine calcification. Thus, we undertook tumor resection via an endoscopic endonasal approach, which resulted in total removal. The pathological diagnosis was a pituitary adenoma with rich calcification. Conclusions: We report a rare case of a large pituitary stone that was successfully removed via an endoscopic endonasal approach. This could therefore be a feasible, effective technique for the removal of pituitary stones, although careful analysis of preoperative magnetic resonance imaging is required.

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PITX2 Expression in Non-functional Pituitary Neuroendocrine Tumor with Cavernous Sinus Invasion.

Tamura R, Ohara K, Morimoto Y, Kosugi K, Oishi Y, Sato M, Yoshida K, Toda M

Endocr Pathol. (Endocrine Pathology) 30 ( 2 ) 81 - 89 2019.03

Research paper (scientific journal), Joint Work, ISSN 10463976

Although most pituitary neuroendocrine tumors (PitNETs) show benign behavior, a significant number of PitNETs exhibit an aggressive course including cavernous sinus (CS) invasion. To date, the cause of CS invasion has not been fully elucidated. In this study, we analyzed the relationship between CS invasion in PitNETs and the expression of PITX2 and SNAIL1, which are the transcription factors associated with the morphogenesis of pituitary gland. Sixty cases with non-functional PitNETs were classified into four types: type 1a, none of CS invasion and suprasellar expansion; type 1b, suprasellar expansion without CS invasion; type 2a, CS invasion without suprasellar expansion; and type 2b, CS invasion with suprasellar expansion. We analyzed the expression of PITX2 and SNAIL1 employing quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry. Other parameters such as mitotic count, Ki-67 index, and p53 expression were also analyzed, which were previously reported as potential tumor proliferative markers in PitNETs. PITX2 expression was significantly higher in PitNETs with CS invasion than PitNETs without CS invasion (P = 0.019). Expression of SNAIL1 was significantly elevated in PitNETs with suprasellar expansion compared with PitNETs without suprasellar expansion (P = 0.02). There was no apparent relationship between CS invasion and mitotic count, Ki-67 index, and p53 expression (mitotic count, P = 0.11; Ki-67 index, P = 0.61; p53, P = 0.66). High PITX2 expression was observed in non-functional PitNETs with CS invasion, suggesting that PITX2 may be involved in CS invasion of PitNETs.

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A pilot study of vaccine therapy with multiple glioma oncoantigen/glioma angiogenesis-associated antigen peptides for patients with recurrent/progressive high-grade glioma.

Kikuchi R, Ueda R, Saito K, Shibao S, Nagashima H, Tamura R, Morimoto Y, Sasaki H, Noji S, Kawakami Y, Yoshida K, Toda M

J.Clin.Med. 8 ( 2 ) 2019.02

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Increased cytotoxicity of herpes simplex virus thymidine kinase expression in human induced pluripotent stem cells

Iwasawa C., Tamura R., Sugiura Y., Suzuki S., Kuzumaki N., Narita M., Suematsu M., Nakamura M., Yoshida K., Toda M., Okano H., Miyoshi H.

International Journal of Molecular Sciences (International Journal of Molecular Sciences) 20 ( 4 ) 2019.02

ISSN 16616596

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Human induced pluripotent stem cells (iPSCs) hold enormous promise for regenerative medicine. The major safety concern is the tumorigenicity of transplanted cells derived from iPSCs. A potential solution would be to introduce a suicide gene into iPSCs as a safety switch. The herpes simplex virus type 1 thymidine kinase (HSV-TK) gene, in combination with ganciclovir, is the most widely used enzyme/prodrug suicide system from basic research to clinical applications. In the present study, we attempted to establish human iPSCs that stably expressed HSV-TK with either lentiviral vectors or CRISPR/Cas9-mediated genome editing. However, this task was difficult to achieve, because high-level and/or constitutive expression of HSV-TK resulted in the induction of cell death or silencing of HSV-TK expression. A nucleotide metabolism analysis suggested that excessive accumulation of thymidine triphosphate, caused by HSV-TK expression, resulted in an imbalance in the dNTP pools. This unbalanced state led to DNA synthesis inhibition and cell death in a process similar to a “thymidine block”, but more severe. We also demonstrated that the Tet-inducible system was a feasible solution for overcoming the cytotoxicity of HSV-TK expression. Our results provided a warning against using the HSV-TK gene in human iPSCs, particularly in clinical applications.

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Analysis of various tracts of mastoid air cells related to CSF leak after the anterior transpetrosal approach

Tamura R., Tomio R., Mohammad F., Toda M., Yoshida K.

Journal of Neurosurgery (Journal of Neurosurgery) 130 ( 2 ) 360 - 367 2019.02

ISSN 00223085

OBJECTIVE The anterior transpetrosal approach (ATPA) was established in 1984 and has been particularly effective for petroclival tumors. Although some complications associated with this approach, such as venous hemorrhage in the temporal lobe and nervous disturbances, have been resolved over the years, the incidence rate of CSF leaks has not greatly improved. In this study, some varieties of air cell tracts that are strongly related to CSF leaks are demonstrated. In addition, other pre- and postoperative risk factors for CSF leakage after ATPA are discussed. METHODS Preoperative and postoperative target imaging of the temporal bone was performed in a total of 117 patients who underwent ATPA, and various surgery-related parameters were analyzed. RESULTS The existence of air cells at the petrous apex, as well as fluid collection in the mastoid antrum detected by a postoperative CT scan, were possible risk factors for CSF leakage. Tracts that directly connected to the antrum from the squamous part of the temporal bone and petrous apex, rather than through numerous air cells, were significantly related to CSF leak and were defined as “direct tract.” All patients with a refractory CSF leak possessed “unusual tracts” that connected to the attic, tympanic cavity, or eustachian tube, rather than through the mastoid antrum. CONCLUSIONS Preoperative assessment of petrous pneumatization types is necessary to prevent CSF leaks. Direct and unusual tracts are particularly strong risk factors for CSF leaks.

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Endonasal Chiasmapexy Using Autologous Cartilage/Bone for Empty Sella Syndrome After Cabergoline Therapy for Prolactinoma

Ishihara E., Toda M., Sasao R., Ozawa H., Saito S., Ogawa K., Yoshida K.

World Neurosurgery (World Neurosurgery) 121 145 - 148 2019.01

ISSN 18788750

Background: Visual field deterioration caused by secondary empty sella after cabergoline therapy for prolactinoma is a rare event. Chiasmapexy is performed to treat empty sella syndrome. Although various materials have been used for the elevation of the optic chasm, the most appropriate material remains to be established. Here, we describe the efficiency of chiasmapexy for empty sella syndrome following dopamine agonist treatment and the utility of septal cartilage and sphenoidal sinus bone as materials for chiasmapexy. Case Description: A 35-year-old male with a history of cabergoline therapy for prolactinoma presented with visual deterioration. His magnetic resonance imaging revealed optic chiasm herniation into the empty sella. Endoscopic endonasal transsphenoidal chiasmapexy was performed using septal cartilage and sphenoidal sinus bone as materials for elevating the chiasm. Visual function improved immediately after operation. Conclusions: Chiasmapexy is an effective surgical method for treating visual deterioration caused by empty sella after cabergoline treatment. Endoscopic endonasal chiasmapexy with septal cartilage and sphenoidal sinus bone is a considerable option because it is minimally invasive and involves decreased risk of infection.

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Visualization of spatiotemporal dynamics of human glioma stem cell invasion.

Tamura R, Miyoshi H, Sampetrean O, Shinozaki M, Morimoto Y, Iwasawa C, Fukaya R, Mine Y, Masuda H, Maruyama T, Narita M, Saya H, Yoshida K, Okano H, Toda M

Molecular Brain 2019

Research paper (scientific journal), Joint Work

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Predictive markers for MGMT promoter methylation in glioblastomas.

Kanazawa T, Minami Y, Jinzaki M, Toda M, Yoshida K, Sasaki H

Neurosurg Rev (Neurosurgical Review) 42 ( 4 ) 867 - 876 2019

Research paper (scientific journal), Joint Work, ISSN 03445607

The promoter methylation status of the O -methylguanine-DNA methyltransferase (MGMT) gene has been described as the most important predictor of chemotherapeutic response and patients’ survival in glioblastomas (GBs). Therefore, prediction of the MGMT promoter methylation status by imaging would help to preoperatively decide the overall treatment strategy as well as surgical strategy. This study aimed to detect imaging parameters to predict MGMT promoter methylation in GBs by using a commercially available software. We investigated three imaging features (ring enhancement, tumor location, and laterality) and apparent diffusion coefficient (ADC) parameters in 48 newly diagnosed GBs treated at Keio University Hospital in 2006 or later. For ADC, texture analyses were performed. Regions of interest (ROIs) were drawn manually with reference to contrast-enhanced areas, excluding necrotic and cystic regions. Mean ADC value and ADC histogram parameters, including kurtosis, skewness, and entropy, were compared with MGMT promoter methylation. Each parameter was evaluated to determine correlation with MGMT promoter methylation, and the parameters with significant associations with the methylation status were correlated with the MGMT-positive cell ratio determined by immunohistochemistry (IHC) analysis. The mean ADC value and ADC entropy were significantly associated with MGMT promoter methylation. The combination of mean ADC value and ADC entropy predicted MGMT promoter methylation, with a PPV of 81.2% and specificity of 88.9%. The mean ADC value and ADC entropy were negatively correlated with the MGMT-positive cell ratio in the IHC analysis. This study demonstrated that texture analyses of ADC histograms in GBs were predictive of MGMT promoter methylation. 6

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Visualization of spatiotemporal dynamics of human glioma stem cell invasion.

Tamura R, Miyoshi H, Sampetrean O, Shinozaki M, Morimoto Y, Iwasawa C, Fukaya R, Mine Y, Masuda H, Maruyama T, Narita M, Saya H, Yoshida K, Okano H, Toda M

Molecular Brain 12 ( 45 ) 2019

Research paper (scientific journal), Joint Work

In Reply to the Letter to the Editor Regarding “Treatment Strategy for Tuberculum Sellae Meningiomas Based on Preoperative Radiologic Assessment”

Kuga D, Toda M, Yoshida K.

World neurosurg 125 ( 1 ) 2019

Research paper (scientific journal)

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Magnetic resonance imaging texture analyses in lower-grade gliomas with a commercially available software: correlation of apparent diffusion coefficient and T2 skewness with 1p/19q codeletion

Kanazawa T, Minami Y, Takahashi H, Fujiwara H, Toda M, Jinzaki M, Yoshida K, Sasaki H

Neurosurg Rev (Neurosurgical Review) 43 ( 4 ) 1211 - 1219 2019

Research paper (scientific journal), Joint Work, ISSN 03445607

Preoperative prediction of molecular information of lower-grade gliomas (LrGGs) helps to determine the overall treatment strategy as well as the initial surgical strategy. This study aimed to detect magnetic resonance imaging (MRI) texture parameters to predict the molecular signature of LrGGs using a commercially available software and routine MR images. Forty-three patients treated at Keio University Hospital who had World Health Organization grade II or III gliomas were included. All patients having preoperative T1- and T2-weighted, fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted (DW) images were also included. Texture analyses of T2, FLAIR, and apparent diffusion coefficient (ADC) histograms were performed using a commercially available software. Texture parameters including kurtosis, skewness, and entropy were investigated to determine any correlation with the presence or absence of isocitrate dehydrogenase (IDH) mutations, 1p/19q codeletion, and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation. ADC skewness and T2 skewness were significantly associated with 1p/19q codeletion status. ADC skewness of ≥ 0.25 predicted 1p/19q codeletion with a sensitivity and specificity of 80% and 65.2%, respectively (AUC = 0.728). T2 skewness of ≥ − 0.11 predicted 1p/19q codeletion with a sensitivity and specificity of 80% and 91.3%, respectively, (AUC = 0.866). None of the texture parameters were associated with IDH mutation and MGMT promoter methylation. MRI texture analysis using a commercially available software demonstrated that T2 skewness could predict 1p/19q codeletion with high sensitivity and specificity, suggesting a clinical utility.

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Analysis of temporobasal vein with short subdural segment for anterior transpetrosal approach

Tamura R, Toda M, Morimoto Y, Sato M, Akiyama T, Yoshida K

World Neurosurg (World Neurosurgery) 132 e554 - e562 2019

Research paper (scientific journal), Joint Work, ISSN 18788750

Background: The anterior transpetrosal approach (ATPA) is applied to petroclival and brainstem lesions. Although neurosurgeons need to minimize the risk of neurologic complications, brain retraction is necessary for procedures of ATPA. Bridging veins (BVs) limit mobility of the temporal lobe. In the present study, BVs around the petrous bone were analyzed, focusing on the dural entrance and termination points. Methods: The relationship between subdural and meningeal segments of temporobasal veins (TBVs) was analyzed by preoperative computed tomography venography in 102 patients who underwent ATPA. TBVs were classified by the dural entrance and termination points. Results: TBVs mainly entered the transverse sinus and rarely entered transverse-sigmoid sinus (T-S) junction and superior petrosal sinus (SPS). TBVs entered a dural sinus either directly or indirectly through a meningeal vein. The changes in vascular diameter of the lumen, shape, and course were identified between the subdural and meningeal segments. Generally, BVs with long subdural segment do not limit mobility of the temporal lobe. TBVs draining into the T-S junction and SPS tended to be shorter than those draining into the transverse sinus. Furthermore, a few TBVs indirectly entered the dural sinuses through the meningeal vein (early dural entrance). The subdural segment of these TBVs was much shorter. Conclusions: TBVs entering the T-S junction or SPS with short subdural segment may limit the mobility of the temporal lobe. Changes in vascular diameter, shape, and course were detected by computed tomography venography, which was helpful to detect the subdural-meningeal transition.

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Identification of KLRC2 as a candidate marker for brain tumor-initiating cells

Ishihara E, Takahashi S, Fukaya R, Ohta S, Yoshida K, Toda M

Neurol Res (Neurological Research) 41 ( 11 ) 1043 - 1049 2019

Research paper (scientific journal), Joint Work, ISSN 01616412

Objective: Brain tumor-initiating cells are characterized by their features of self-renewal, multi-lineage differentiation, and tumorigenicity. We analyzed the gene expression of brain tumor-initiating cells to identify their novel cellular markers. Methods: We performed cDNA microarray, in silico expressed sequence tags (ESTs), RT-PCR, and q-PCR analyses. Results: We identified 10 genes that were more highly expressed in brain tumor-initiating cells than in neural stem cells. In addition, we identified 10 other genes that were more highly expressed in brain tumor-initiating cells than in glioma cell line cells from the cDNA microarray analysis. Using the EST database, we looked to see if the 20 genes were expressed more highly in gliomas, compared with normal adult brains. Among the 20 genes, five (KLRC2, HOXB2, KCNJ2, KLRC1, and COL20A1) were expressed more than twice in glioma samples, compared with normal adult brains, and, therefore, were referred for further evaluation. RT-PCR was conducted using cDNA samples obtained from neural stem cells, normal brain tissue, fetal brain tissue, glioma cell lines, and glioma tumor-initiating cell lines. KLRC2, a transmembrane activating receptor in natural killer cells, was expressed more highly in glioma-initiating cells than in neural stem cell lines or normal adult brain tissue. The q-PCR analysis revealed that expression of KLRC2 was significantly higher in brain tumor-initiating cells compared to normal brain controls. Conclusion: KLRC2 could be a novel cellular marker for brain tumor-initiating cells.

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Early prediction of clinical outcomes in patients with aneurysmal subarachnoid hemorrhage using computed tomography texture analysis

Kanazawa T, Takahashi S, Minami Y, Jinzaki M, Toda M, Yoshida K

J Clin Neurosci (Journal of Clinical Neuroscience) 71 144 - 149 2019

Research paper (scientific journal), Joint Work, ISSN 09675868

Radiological evaluation of subarachnoid hemorrhage (SAH) is often subject to interobserver variability. The aim of this study was to retrospectively detect computed tomography (CT) texture parameters in the early postictal state to predict cerebral vasospasm, delayed cerebral ischemia (DCI), and functional outcome in aneurysmal SAH using quantitative CT texture analysis (CTTA) via a commercially available software program and routine CT images. 40 patients with aneurysmal SAH surgically treated at the Keio University Hospital during a four-year period were analyzed. CT texture analyses were performed using a commercially available software program (Synapse Vincent). The following texture parameters of blood clots in the subarachnoid space and cerebral edema were assessed: mean CT value, entropy, skewness, and kurtosis. The mean CT value of blood clots in the subarachnoid space was significantly associated with cerebral vasospasm, DCI, and functional outcome. The mean CT value ≥ 49.64 Hounsfield units (HU) predicted cerebral vasospasm with a sensitivity and specificity of 85.7% and 61.5%, respectively (area under the curve [AUC] = 0.758). The mean CT value ≥ 49.95 HU predicted DCI with a sensitivity and specificity of 100% and 60.6%, respectively (AUC = 0.810). The mean CT value ≥ 53.00 HU predicted poor functional outcome with a sensitivity and specificity of 56.3% and 91.7%, respectively (AUC = 0.747). CTTA using a commercially available software program demonstrated that the mean CT value of clots in the subarachnoid space in the early postictal state could predict vasospasm, DCI, and clinical outcome with a high sensitivity and specificity.

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A VEGF receptor vaccine demonstrates preliminary efficacy in Neurofibromatosis type 2.

Tamura R, Fujioka M, Morimoto Y, Ohara K, Kosugi K, Oishi Y, Sato M, Ueda R, Fujiwara H, Hikichi T, Noji S, Oishi N, Ogawa K, Kawakami Y, Ohira T, Yoshida K, Toda M

Nature Commun (Nature Communications) 10 ( 1 ) 5758 2019

Research paper (scientific journal), Joint Work

The anti-VEGF antibody bevacizumab has shown efficacy for the treatment of neurofibromatosis type 2 (NF2). Theoretically, vascular endothelial growth factor receptors (VEGFRs)-specific cytotoxic T lymphocytes (CTLs) can kill both tumor vessel cells and tumor cells expressing VEGFRs. Here we show an exploratory clinical study of VEGFRs peptide vaccine in seven patients with progressive NF2-derived schwannomas. Hearing improves in 2/5 assessable patients (40%) as determined by international guidelines, with increases in word recognition scores. Tumor volume reductions of ≥20% are observed in two patients, including one in which bevacizumab had not been effective. There are no severe adverse events related to the vaccine. Both VEGFR1-specific and VEGFR2-specific CTLs are induced in six patients. Surgery is performed after vaccination in two patients, and significant reductions in the expression of VEGFRs in schwannomas are observed. Therefore, this clinical immunotherapy study demonstrates the safety and preliminary efficacy of VEGFRs peptide vaccination in patients with NF2.

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Relationship between pneumatization of lateral recess in the sphenoid sinus and removal of cavernous sinus invasion in pituitary adenomas by endoscopic endonasal surgery.

Kosugi K, Tamura R, Mase T, Tamura H, Jinzaki M, Yoshida K, Toda M

Surg Neurol Int 10 222 2019

Research paper (scientific journal), Joint Work

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Long-Term Clinical Outcome of First Recurrence Skull Base Meningiomas.

Kuranari Y, Tamura R, Tsuda N, Kosugi K, Morimoto Y, Yoshida K, Toda M

J Clin Med 9 ( 1 ) e106 2019

Research paper (scientific journal), Joint Work

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Surgical management of trigeminal schwannomas: Preservation of the trigeminal nerve

Toda M., Tamura R., Yoshida K.

Japanese Journal of Neurosurgery (Japanese Journal of Neurosurgery) 28 ( 7 ) 407 - 413 2019

ISSN 0917950X

Trigeminal schwannomas can develop anywhere along the course of the trigeminal root, ganglion, and nerve branches. The most frequent tumor site is Meckel’s cave. The tumor, is dumbbell in shape, often extends to the posterior cranial fossa. A series of surgical approaches, which primarily include skull base extradural approaches, used for the management of trigeminal schwannomas has been discussed based on tumor site. More recently, an endoscopic endonasal approach has been used for lesions in Meckel’s cave, pterygoid palatine fossa, and infratemporal fossa. This article describes anatomy‒based surgical approaches for the management of trigeminal schwannoma and surgical approaches aimed at functional preservation.

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Endoscopic endonasal approach combined with a simultaneous transcranial approach for giant pituitary tumors.

Kuga D, Toda M, Ozawa H, Ogawa K, Yoshida K

World Neurosurg 121 173 - 179 2019

Research paper (scientific journal), Joint Work, Accepted

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In Reply to the Letter to the Editor Regarding “Treatment Strategy for Tuberculum Sellae Meningiomas Based on Preoperative Radiologic Assessment”

114 Kuga D, Toda M, Yoshida K.

World neurosurg 125 ( 1 ) 2019

Research paper (scientific journal), Joint Work

Difference in Immunosuppressive Cells Between Peritumoral Area and Tumor Core in Glioblastoma

Tamura R., Ohara K., Sasaki H., Morimoto Y., Kosugi K., Yoshida K., Toda M.

World Neurosurgery (World Neurosurgery) 120 e601 - e610 2018.12

ISSN 18788750

Background: Vascular endothelial growth factor (VEGF)-A and VEGF receptor expression in the peritumoral brain zone (PBZ) differs from that in the tumor core (TC) of glioblastoma. To date, no comparative study has investigated the expression of immunosuppressive cells in the PBZ and TC of glioblastoma. Methods: In 10 patients with newly diagnosed glioblastoma, we used immunohistochemistry to analyze the expression of VEGF-A, hypoxia-inducible factor-1α, programmed cell death-1 (PD-1), Foxp3, CD163, CD4, and CD8 to assess the immunosuppressive microenvironment. Results: The number of Foxp3 and CD163 cells was significantly greater in the TC than in the PBZ and correlated with greater expression of hypoxia-inducible factor-1α and VEGF-A in the TC than in the PBZ. The number of CD8 T cells was lower in the TC than in the PBZ, and the TC had more PD-1 CD8 T cells compared with the PBZ. These results suggest that the hypoxic condition could be associated with PD-1 expression on lymphocytes, the distribution of Foxp3 regulatory T cells and CD163 tumor-associated macrophages. Conclusions: The present study reports the first clinicopathologic features of the differences in immunosuppressive cells and the expression of immune checkpoint molecules between the TC and PBZ of glioblastoma. + + + + + + +

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Pros and cons of using ORBEYE™ for microneurosurgery

Takahashi S., Toda M., Nishimoto M., Ishihara E., Miwa T., Akiyama T., Horiguchi T., Sasaki H., Yoshida K.

Clinical Neurology and Neurosurgery (Clinical Neurology and Neurosurgery) 174 57 - 62 2018.11

ISSN 03038467

© 2018 Elsevier B.V. Objective: To evaluate the pros and cons of using a newly developed microscope, ORBEYE™, during microneurosurgery. Patients and methods: ORBEYE™ use in 14 microneurosurgical procedures was retrospectively assessed by nine neurosurgeons after the procedure. A questionnaire comprising 20 questions was designed and used for evaluation. Results: Compared with the current gold standard, the binocular microscope, ease of setting up the equipment was scored the highest, whereas ease of conducting surgery in a position of an assistant was scored the lowest. Among characteristics of ORBEYE™ itself, the space-saving feature was scored the highest and was followed by the ability to perform procedures in a comfortable position. The only characteristic that was rated below average was ease of operation in a position of an assistant. Neurosurgeons with greater experience (more than five procedures using ORBEYE™) provided significantly higher scores (p = 0.0196) for characteristics of ORBEYE™ itself compared with neurosurgeon with fewer ORBEYE™ experience. Conclusions: The main benefits of the ORBEYETM are its compact size and freedom from focusing through the eye lens of a conventional binocular microscope. However, it appears to be disadvantageous for operating in a position of an assistant because the surgical field has a rotated view on the monitor from a position of an assistant. Nonetheless, because of certain advantages, we believe the ORBEYE™ could be of additional help to use of conventional binocular microscope at the moment and will facilitate microneurosurgery in the future.

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Intraosseous venous structures adjacent to the jugular tubercle associated with an anterior condylar dural arteriovenous fistula.

Mizutani T, Akiyama T, Minami Y, Toda M, Fujiwara H, Jinzaki M, Yoshida K

Neuroradiology (Neuroradiology) 60 ( 5 ) 487 - 496 2018.05

ISSN 00283940

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: Although involvement of the osseous component with an anterior condylar dural arteriovenous fistula (AC-DAVF) has been frequently described, osseous venous structures in which AC-DAVFs develop have not been fully elucidated. We investigated osseous venous structures adjacent to the hypoglossal canal in normal controls and patients with AC-DAVFs. Methods: The study included 50 individuals with unruptured aneurysms as normal controls and seven patients with AC-DAVFs. Osseous venous structures adjacent to the hypoglossal canal in normal controls were analyzed using computed tomography (CT) digital subtraction venography. In patients with AC-DAVFs, the fistulous pouches, draining veins, and surrounding venous structures were examined using cone beam CT. Results: In 46.0% of laterals in normal controls, osseous venous structures were visualized within the jugular tubercle superomedially to the hypoglossal canal. We named these structures the jugular tubercle venous complex (JTVC). The JTVC was always continuous with the anterior condylar vein and was sometimes connected to surrounding venous channels. We detected nine fistulous pouches in the seven patients with AC-DAVFs. The fistulous pouches were in the JTVC (33.3%), anterior condylar vein (33.3%), and other venous channels within the exoccipital region (33.3%). Conclusion: Although the JTVC is a venous structure frequently found in normal people, it had not been investigated until now. The venous channel between the anterior condylar vein and JTVC is a common origin site for AC-DAVFs, and it was associated with 66.6% of the AC-DAVF cases in the current study.

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A pilot study of peptide vaccines for VEGF receptor 1 and 2 in patients with recurrent/progressive high grade glioma.

Shibao S, Ueda R, Saito K, Kikuchi R, Nagashima H, Kojima A, Kagami H, Sasaki H,　Noji S, Kawakami Y, Yoshida K, Toda M

Oncotarget (Oncotarget) 9 ( 30 ) 21569 - 21579 2018.04

© Shibao et al. Object: Early-phase clinical studies of glioma vaccines have shown feasibility and encouraging preliminary clinical activity. A vaccine that targets tumor angiogenesis factors in glioma microenvironment has not been reported. Therefore, we performed a pilot study to evaluate the safety and immunogenicity of a novel vaccination targeting tumor angiogenesis with synthetic peptides for vascular endothelial growth factor (VEGF) receptor epitopes in patients with recurrent/progressive high grade gliomas. Methods: Eight patients received intranodal vaccinations weekly at a dose of 2mg/kg bodyweight 8 times. T-lymphocyte responses against VEGF receptor (VEGFR) epitopes were assessed by enzyme linked immunosorbent spot assays. Results: This treatment was well-tolerated in patients. The first four vaccines induced positive immune responses against at least one of the targeted VEGFR epitopes in the peripheral blood mononuclear cells in 87.5% of patients. The median overall survival time in all patients was 15.9 months. Two achieved progression-free status lasting at least 6 months. Two patients with recurrent GBM demonstrated stable disease. Plasma IL-8 level was negatively correlated with overall survival. Conclusion: These data demonstrate the safety and immunogenicity of VEGFR peptide vaccines targeting tumor vasculatures in high grade gliomas.

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The analysis of the cerebral venous blood volume in cavernous sinus using 320 row multi-detector CT.

Mizutania K, Toda M,　Yajima Y, Akiyama T, Fujiwara H, Yoshida K, Jinzaki M

Clin Neurol Neurosurg (Clinical Neurology and Neurosurgery) 167 11 - 16 2018.04

ISSN 03038467

© 2018 Elsevier B.V. Objectives: : Functional venous anatomy in the brain has been mostly understood from the morphological and embryological points of view and no published study has directly evaluated the blood flow volume of cerebral small veins. We developed a method to directly evaluate the relative blood volume in small venous channels using multi-detector computed tomography (CT) and applied it to evaluate the blood volume in each tributary of the cavernous sinus, which plays an important role in cerebral venous drainage. Patients and Methods: : Ten patients with small brain tumors who had normal venous anatomy were included in the present study. All of them underwent preoperative 320-row multi-detector CT. After injecting the contrast bolus, we measured the Hounsfield units (HUs) at 10 time point over 60 s in each tributary of the cavernous sinus. The gamma distribution fitting to each HU enabled us to obtain a time-density curve and determine the relative venous volume in each venous channel. Results: : In terms of blood volume, the superficial middle cerebral vein and inferior petrosal sinus were the largest inflow and outflow channels of the cavernous sinus and accounted for 36.1% and 24.7% of its inflow and outflow on average, respectively. The superior orbital vein did not contribute to the blood volume passing through the cavernous sinus in the current study. Conclusions: : The present study allowed us to determine the relative blood volume in each tributary of the cavernous sinus, which was very useful to understand the physiological actual venous drainage pattern concerning the cavernous sinus in normal anatomy.

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An Analysis of Various Tracts of Mastoid Air Cells Related to Cerebrospinal Fluid Leak after the Anterior Transpetrosal Approach.

Tamura R,　Tomio　R,　Mohammad　F,　Toda　M, Yoshida　K

Journal of Neurosurgery 16 1 - 8 2018.03

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Histopathological vascular investigation of the peritumoral brain zone of glioblastomas.

Tamura R, Ohara K, Sasaki H, Morimoto Y, Yoshida K, Toda M.

J Neurooncol (Journal of Neuro-Oncology) 136 ( 2 ) 233 - 241 2018.01

ISSN 0167594X

© 2017, Springer Science+Business Media, LLC. To date, no histopathological vascular investigation focusing on peritumoral brain zone (PBZ) has been reported for glioblastoma. We analyzed 10 newly diagnosed cases of glioblastomas. For these PBZs, histopathological investigation was performed by hematoxylin–eosin (H&E) staining and immunohistochemistry was analyzed for CD31, CD34, Factor VIII, VEGF, VEGFR-1/2, Ki67, p53 and nestin. Although it was difficult to identify PBZ by H&E, Ki67 and p53 staining, there were apparent differences in nestin staining among PBZ, tumor core (TC), and normal zone (NZ). Therefore, in this study, we divided PBZ from TC and NZ by nestin staining. Differences in histological features, microvessel density, expression of VEGF and its receptors were assessed for PBZ, TC and NZ. The microvessel density, as determined by counting CD31, CD34 and VEGF receptors, and VEGF-A expression were lower in PBZ than TC. The expression patterns for CD31, CD34 and VEGF receptors in vessels show dissociation in PBZ. In addition, the vascular characteristics of the PBZ may correlate with findings of radiographic imaging. We provide the first clinicopathological evidence that PBZ exhibits unique angiogenic characteristics. These in situ observations will help to elucidate the mechanisms of tumor recurrence.

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Surgical treatment of cavernous sinus lesion in patients with non-functioning pituitary adenomas via the endoscopic endonasal approach.

Toda M, Kosugi K, Ozawa H, Ogawa K, Yoshida K

J Neurol Surg B Skull Base (Journal of Neurological Surgery, Part B: Skull Base) in press ( 5 ) S311 - S315 2018

ISSN 2193634X

© 2018 Georg Thieme Verlag KG Stuttgart . New York. Objective The main purpose of this article is to assess the effectiveness and safety of surgery via the endoscopic endonasal approach (EEA) for cavernous sinus (CS) lesion in patients with nonfunctioning pituitary adenomas (NFPA). Design Retrospective study. Setting Keio University Hospital. Participants Thirty patients who underwent CS surgery via the EEA between 2009 and 2017 for Knosp grade 4 NFPA with pre- and postoperative magnetic resonance imaging available for volumetric analysis. Main Outcome Measures Clinical presentation, extent of resection, and surgical complications. Results Gross total and near total resection of CS tumors was achieved in 12/30 (40%) cases of Knosp grade 4 NFPA. The average resection rate of CS lesions in these 30 patients was 73.5%; 77.3% in primary cases and 70.1% in recurrent cases that did not vary significantly. Preoperative visual disturbance and oculomotor nerve palsy improved in 12/19 (63.1%) and - (60%) cases, respectively. Complications associated with CS via the EEA were postoperative cerebrospinal leakage (1/30, 3.3%), meningitis (1/30, 3.3%), and transient cranial nerve palsy (2/30, 6.7%). These complications except a case of mild transient abducens nerve palsy occurred in recurrent cases with subdural lesions. Conclusions Although the optimal management of CS lesions in NFPA is controversial, debulking via the EEA is an effective and safe option that improves neurological symptoms and enables effective adjuvant radiotherapy. Recurrent cases with subdural invasion are technically challenging, even using the EEA, and special care is required to avoid complications.

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Preoperative prediction of solitary fibrous tumor/hemangiopericytoma and angiomatous　meningioma using magnetic resonance imaging texture analysis

Kanazawa　T,　Toda M

World Neurosurgery (World Neurosurgery) in press e1208 - e1216 2018

ISSN 18788750

© 2018 Elsevier Inc. Background: Solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is radiologically difficult to distinguish from meningioma, especially angiomatous meningioma. This study aimed to detect texture parameters to distinguish SFT/HPC from angiomatous meningioma using magnetic resonance imaging texture analysis with commercially available software. Methods: We retrospectively investigated textural parameters in 43 newly diagnosed SFTs/HPCs, angiomatous meningiomas, and other World Health Organization (WHO) grade I meningiomas treated at Keio University Hospital. For T1 contrast-enhanced, T2, and apparent diffusion coefficient (ADC) images, texture analyses were performed. Regions of interest were drawn manually with reference to the greater signal on contrast-enhanced T1-weighted images. ADC values and texture parameters, including kurtosis, skewness, and entropy, were evaluated and compared between these 3 groups. Results: The mean ADC value was significantly high in angiomatous meningioma, compared with SFT/HPC and other WHO grade I meningioma. ADC entropy was highest in SFT/HPC, followed by angiomatous and other WHO grade I meningioma. T2 skewness was significantly high in SFT/HPC, compared with angiomatous and other WHO grade I meningioma. T1 contrast-enhanced skewness was significantly low in angiomatous meningioma, compared with other WHO grade I meningioma. Mean ADC value distinguished SFT/HPC from angiomatous meningioma with a positive predictive value (PPV) of 62.5% and specificity of 62.5%. ADC entropy distinguished SFT/HPC from angiomatous meningioma with a PPV of 100% and specificity of 100%. ADC skewness distinguished SFT/HPC from angiomatous meningioma with a PPV of 66.7% and specificity of 71.4%. Conclusions: This study demonstrated that magnetic resonance imaging texture analysis was useful for distinguishing SFT/HPC from meningioma, especially angiomatous meningioma.

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Treatment strategy for tuberculum sellae meningiomas based on a preoperative radiological assessment

Toda M

World Neurosurgery (World Neurosurgery) in press e1279 - e1288 2018

Research paper (scientific journal), ISSN 18788750

© 2018 Elsevier Inc. Background: Although there are several surgical approaches for the treatment of tuberculum sellae (TS) meningiomas, clear indications for non–large TS meningiomas are still lacking. Methods: Our case series included 20 patients with TS meningiomas (<3 cm). We classified the tumors into 3 groups based on their radiologic relationship with the optic chiasm: type I, tumor with intact optic chiasm; type II, tumor with superiorly deviated optic chiasm; and type III, tumor with posteriorly deviated optic chiasm. Clinical outcomes, radiologic findings, and surgical approaches for the removal of each tumor type were retrospectively reviewed. Results: Resections using a pterional approach, interhemispheric approach, and an endoscopic endonasal approach were performed in three groups of 6, 7, and 7 patients. The rate of total tumor resection was equivalent across approaches, whereas postoperative visual dysfunction was observed in 1 patient (7.69%) undergoing a transcranial approach. Our evaluation of the sphenoid sinus shape across radiographs revealed that the patterns of bony wall elongation attached to these tumors significantly differed among tumor types, indicating that tumor origin and growth direction might affect the patterns of optic chiasm deviation. In addition, selective elongation of the TS provided a favorable surgical corridor for an endoscopic endonasal approach, especially in type II tumors. These results indicate that this tumor classification influenced surgical approach selection for non–large TS meningiomas. Conclusions: The aim of surgery is maximal tumor resection without causing visual dysfunction. The classification proposed here may predict surgical risk associated with meningioma resection and further inform the selection of a surgical approach.

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Skull base venous anatomy associated with endoscopic skull base neurosurgery: a literature review

Toda M

World Neurosurgery (World Neurosurgery) in press 405 - 414 2018

ISSN 18788750

© 2018 Elsevier Inc. An understanding of the anatomy and function of the skull base venous channels is fundamentally important for safe performance of endoscopic surgery for skull base lesions. This review focuses on 4 skull base venous channels—namely, the intercavernous sinuses, basilar plexus, osseous veins, and inferior petroclival vein—because these have been less recognized by neurosurgeons than other major venous channels such as the inferior petrosal sinus. We reviewed the literature concerning these 4 venous channels and discussed their anatomy and function. The literature review was mainly based on an electronic search in PubMed using the following terms: “intercavernous sinus,” “basilar plexus,” “emissary veins,” “diploic vein,” “basilar plexus,” “intraosseous vein,” “inferior petroclival/petro-occipital vein,” and “transclival.” A total of 50 articles were included in this review. Detailed anatomic features of the 4 structures have been elucidated in the literature. All of these venous channels run along the skull base and have multiple connections with surrounding venous structures. Because of their location, they occasionally obstruct the surgical view and are sometimes implicated in intraoperative hemorrhage, air embolism during endoscopic skull base surgery, and postoperative hematoma. They usually function as a venous reservoir of cranial venous drainage; however, they are less often directly involved in normal brain perfusion. Knowledge about the functional and morphologic anatomy of the skull base venous channels is important for neurosurgeons to avoid unexpected complications during endoscopic skull base surgery.

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Endoscopic endonasal approach combined with a simultaneous transcranial approach for giant pituitary tumors.

TODA MASAHIRO

World Neurosurgery (World Neurosurgery) in press 173 - 179 2018

Research paper (scientific journal), ISSN 18788750

© 2018 Elsevier Inc. Background: The endoscopic endonasal approach is widely used for treating giant pituitary adenomas. However, a small subset of tumors is still challenging to treat, and the risk of complications increases when an endoscopic endonasal approach alone is used. The simultaneous combined endoscopic endonasal and transcranial approach is a surgical option for such difficult adenomas; however, very few studies have described the technical nuances and benefits of this approach. Methods: We treated 3 patients with giant pituitary adenoma and 1 patient with pituicytoma. Radiologic findings and clinical outcomes were retrospectively reviewed. Results: All patients had preoperative visual disturbances. A pterional approach was combined with an endoscopic endonasal approach to treat all the patients. Near-total and subtotal tumor removal was accomplished in 3 patients; however, only partial tumor removal was possible in 1 patient. Postoperative visual function improved in 3 patients, but there were no changes in 1 patient. There were no major complications; however, each patient developed either adrenocorticotropic hormone (ACTH) and thyroid-stimulating hormone deficiency or ACTH deficiency and persistent diabetes. Importantly, no cerebrospinal fluid leakage was observed in the patients. Conclusions: Our simultaneous combined endoscopic and transcranial approach offers safe tumor resection and a low rate of complications. In this procedure, it is important that tumor debulking be performed by the main surgeon via a single surgical route and not by 2 surgeons using the simultaneous endonasal and transcranial approach, to avoid interference in the surgical field. This approach may be considered as a surgical option for carefully selected tumors in the sellar region.

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Combined endoscopic endonasal and video-microscopic transcranial approach with preoperative embolization for a posterior pituitary tumor.

Yoshida Keisuke, Toda M, Akiyama T, Takahashi S, Nishimoto M, Ozawa H, Ikari Y, Yoshida K

World Neurosurgery (World Neurosurgery) 119 201 - 208 2018

ISSN 18788750

© 2018 Elsevier Inc. Background: Posterior pituitary tumor is rare, and its optimal surgical strategy is undetermined. Surgical removal of posterior pituitary tumors is often complicated by their hypervascularity. Prevention and preparation for excessive hemorrhage is crucial for safe resection. Case Description: A 69-year-old woman presented with bitemporal hemianopsia and was found to have a sellar tumor with suprasellar extension, resembling a pituitary adenoma. Microscopic transsphenoidal resection was attempted but was interrupted by a massive intraoperative hemorrhage. Pathologic diagnosis was a spindle cell oncocytoma, and she was referred to our institution. She underwent preoperative embolization to decrease tumor vascularity, and resection was performed using a combined endoscopic endonasal and video-microscopic transcranial approach, using a 4K three-dimensional (3D) video microscope. The final diagnosis was a posterior pituitary tumor with immunopositivity for thyroid transcription factor-1, with preferred interpretation as a pituicytoma. Conclusions: A combined endonasal and transcranial approach with preoperative embolization is a useful strategy for hypervascular posterior pituitary tumors. A 4K 3D video microscope is compact, and it provides high-resolution images, contributing larger surgical space and facilitating a multi-team surgery.

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Severe headache in a patient with meningioma showing extensive dural tail correlates with IgG4-positive plasma cells and eosinophils: A case report and review of literature

Kuranari Y., Tamura R., Mikami S., Ohara K., Toda M., Yoshida K.

Surgical Neurology International (Surgical Neurology International) 9 ( 1 ) 202 2018

Research paper (scientific journal)

© 2018 Surgical Neurology International | Published by Wolters Kluwer - Medknow. Background: Meningiomas originate from meningothelial cells of the arachnoid membrane. Few cases of meningioma with infiltration of inflammatory cells, such as lymphocytes and plasma cells, have been reported, and the mechanisms underlying meningioma-induced inflammatory reactions have not been fully elucidated. Case Description: In this study, we report an extremely rare case of meningioma with infiltration of both IgG4-positive plasma cells and eosinophils showing extensive dural tail and reactive inflammation of the surrounding arachnoid tissue. The main clinical manifestation was a severe headache, which was improved by surgical excision of the tumor. Conclusion: Only 8 cases of meningioma with IgG4-positive plasma cells have been reported, and only one case exhibited eosinophil infiltration. IgG4-related inflammatory response might mediate inflammation in surrounding tissue, resulting in thickening of the dura adjacent to a meningioma and severe headache. The mechanisms underlying inflammation by meningiomas require further investigation.

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Subtemporal approach: Intra- and extradural approach, anterior petrosal approach, and endonasal approach

Toda M., Yoshida K.

Japanese Journal of Neurosurgery (Japanese Journal of Neurosurgery) 27 ( 11 ) 818 - 827 2018

ISSN 0917950X

The subtemporal approach is applied to the middle cranial fossa and infratemporal fossa in addition to the tentorial incisura, petroclivus, and brain stem lesions. To minimize compression damage to the temporal lobe, it is essential to perform the craniotomy along the middle cranial fossa, to remove the zygomatic arch for supratentorial lesions, and to remove the petrous pyramid for infratentorial lesions. To avoid venous damage, the drainage pathways of the superficial sylvian vein and bridging veins, including Labbé’s vein, should be preoperatively evaluated. Furthermore, with the recent advances in endoscopic surgery, it has become possible to approach the middle cranial fossa and infratemporal fossa endonasally. In the endonasal approach, surgical simulation is important because of the variations in the nasal cavity and paranasal sinus structures. In this article, we outline the surgical anatomy of the middle cranial fossa required for the subtemporal approach, including the endonasal approach, and variations in the venous drainage of the superficial sylvian vein and petrosal vein. Moreover, we describe the treatment of pontine lesions by the subdural subtemporal approach, Meckel cave lesions by the epidural subtemporal approach, petroclival lesions by the anterior transpetrosal approach, and infratemporal lesions by the endonasal approach.

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Clinical and molecular prognostic factors for long-term survival of the patients with glioblastomas in a single institutional consecutive cohort.

Nakagawa Y, Sasaki H, Ohara K, Ezaki T, Toda M, Ohira T, Kawase T, Yoshida K.

World Neurosurg. 106 165 - 173 2017.10

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The impact of several craniotomies on transcranial motor evoked potential monitoring during neurosurgery.

Tomio R, Akiyama T, Toda M, Ohira T, Yoshida K

J Neurosurg. 127 ( 3 ) 543 - 552 2017.09

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Functional analysis of the DEPDC1 oncoantigen in malignant glioma and brain tumor initiating cells.

Kikuchi R, Sampetrean O, Saya H, Yoshida K, Toda M

J Neurooncol. 133 ( 2 ) 297 - 307 2017.06

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Analysis of the venous channel within the clivus using multidetector computed tomography digital subtraction venography.

Mizutani K, Toda M, Kurasawa J, Akiyama T, Fujiwara H, Jinzaki M, Yoshida K

Neuroradiology 59 ( 3 ) 213 - 219 2017.03

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Functional analysis of KIF20A, a potential immunotherapeutic target for glioma

Saito K, Ohta S, Kawakami Y, Yoshida K, Toda M

J Neurooncol 132 ( 1 ) 63 - 74 2017.03

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Delayed and isolated oculomotor nerve palsy following minor head trauma.

Nakagawa Y, Toda M, Shibao S, Yoshida K.

Surg Neurol Int. 8 ( 20 ) 2017.02

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Surgical Outcome of Endoscopic Endonasal Surgery for Non-Functional Pituitary Adenoma by a Team of Neurosurgeons and Otolaryngologists Adenoma by a Team of Neurosurgeons and Otolaryngologists.

Kikuchi R, Toda M, Tomita T, Ogawa K, Yoshida K

Turkish Neurosurg 27 ( 1 ) 1 - 7 2017.01

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Transvenous Embolization of the Basilar Plexus Before Endoscopic Transsphenoidal Transclival Surgery.

Mizutani K, Akiyama T, Toda M, Kanazawa T, Kamamoto D, Yoshida K

World Neurosurg. 97 756 - 756 2017.01

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Endonasal endoscopic approach for a giant cavernous sinus meningioma that extended to the middle cranial fossa with preoperative embolization

Tamura R, Toda M, Kohno M, Ozawa H, Tomita T, Akiyama T, Ogawa K, Yoshida K

Interdisciplinary Neurosurgery 6 20 - 22 2016.12

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Analysis of the medial opticocarotid recess in patients with pituitary macroadenoma using three-dimensional images.

Kikuchi R, Toda M, Wakahara S, Fujiwara H, Jinzaki M, Yoshida K

World Neurosurg. 93 139 - 143 2016.09

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The analysis of the petrosal vein to prevent venous complications during the anterior transpetrosal approach in the resection of petroclival meningioma

Mizutani K, Toda M, Yoshida K

World Neurosurg. 93 175 - 182 2016.09

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Vascularized middle turbinate flap for the endoscopic endonasal reconstruction of the anterior olfactory groove

Tamura R, Toda M, Kohno M, Watanabe Y, Ozawa H, Tomita T, Ogawa K, Yoshida K

Neurosurg Rev 39 ( 2 ) 297 - 302 2016.04

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MIF maintains the tumorigenic capacity of brain tumor-initiating cells by directly inhibiting p53

Fukaya R, Ohta S, Yaguchi T, Matsuzaki Y, Sugihara E, Okano H, Saya H, Kawakami Y, Kawase T, Yoshida K, Toda M

Cancer Res 76 ( 9 ) 2813 - 2823 2016.03

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Pathological Location of Cranial Nerves in Petroclival Lesions: How to Avoid Their Injury during Anterior Petrosal Approach.

Borghei-Razavi H, Tomio R, Fereshtehnejad SM, Shibao S, Schick U, Toda M, Yoshida K, Kawase T

J Neurol Surg B Skull Base 77 ( 1 ) 6 - 13 2016.02

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Various patterns of the middle cerebral vein and preservation of venous drainage during the anterior transpetrosal approach

Shibao S, Toda M, Orii M, Fujiwara H, Yoshida K

J Neurosurg 124 ( 2 ) 432 - 439 2016.02

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Editorial: Temporal lobe venous preservation Response.

Shibao S, Toda M, Yoshida K

J Neurosurg 124 ( 2 ) 429 - 430 2016.02

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Sigmoid incision rescue nasoseptal flap technique for endoscopic endonasal skull base surgery

Ozawa H, Tomita T, Watanabe Y, Sekimizu M, Ito F, Ikari Y, Saito S, Toda M, Ogawa K

Acta Otolaryngol Epub ahead of print 2016.02

Anterior Petrosal approach: The Safety of Kawase triangle as an anatomical landmark for anterior petrosectomy in petroclival meningiomas

Borghei-Razavi H, Tomio R, Fereshtehnejad SM, Shibao S, Schick U, Toda M, Kawase T, Yoshida K

Clin Neurol Neurosurg 139 ( 2015 ) 282 - 287 2015.11

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Giant cell tumors of the clivus: case report and literature review.

Shibao S, Toda M, Yoshida K

Surg Neurol Int 6 ( (Suppl 25) ) S623 - S627 2015.11

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Analysis of sphenoid sinus lateral pneumatization for endonasal endoscopic surgery.

Kikuchi R, Toda M, Tomita T, Ogawa K, Yoshida K

Surg Neurol Int 2015 ( 6:166 ) 2015.10

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Analysis of the intercavernous sinus in sellar lesions using multidetector computed tomography digital subtraction venography.

Mizutani K, Toda M, Yoshida K

World Neurosurg pii: S1878-8750(15)01095-5. 2015.09

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Upfront chemotherapy and subsequent resection for molecularly defined gliomas

Sasaki Hikaru, Hirose Yuichi, Yazaki Takahito, Kitamura Yohei, Katayama Makoto, Kimura Tokuhiro, Fujiwara Hirokazu, Toda Masahiro, Ohira Takayuki, Yoshida Kazunari

Journal of Neuro-Oncology 124 ( 1 ) 127 - 135 2015.08

ISSN 0167-594X

Functional preservation is critical in glioma surgery, and the extent of resection influences survival outcome. Neoadjuvant chemotherapy is a promising option because of its potential to facilitate tumor shrinkage and maximum tumor resection. The object of this study was to assess the utility of the neoadjuvant strategy in a prospective series of gliomas with favorable molecular status. Twenty-six consecutive cases of diffuse gliomas of WHO grade II or III with either 1p19q codeletion or MGMT methylation were treated with upfront chemotherapy following maximal safe removal. In cases of incomplete initial surgery, second-look resection was intended after tumor volume decrease by chemotherapy. Among 22 evaluable cases, chemotherapy led to a median change in the sum of the product of perpendicular diameters of −35 %, and 14 out of the 22 cases (64 %) showed objective response. Second-look resection after tumor volume decrease was performed in 12 out of 19 cases of incomplete initial surgery (GTR/STR 9, removal of residual methionine PET uptake 3). The median progression-free survival among the 22 patients with grade II tumors was 57 months, with some cases showing durable progression-free survival after second-look resection. MIB-1 indices of the second-look resected tumors were lower than those of the initial tumors, and the methylation status of the MGMT gene was unchanged. Neoadjuvant chemotherapy based on molecular guidance often produces significant volume decrease of incompletely resected gliomas. Radical second-look resection is an optional advantage of upfront chemotherapy for chemosensitive gliomas compared with initial radiotherapy.

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Steroid psychosis caused by perioperative steroid replacement for pituitary adenoma

Mizutani Katsuhiro, Toda Masahiro, Kikuchi Ryogo, Uchida Hiroyuki, Yoshida Kazunari

Keio Journal of Medicine 64 ( 1 ) 11 - 15 2015.03

ISSN 0022-9717

Steroid psychosis is a frequent complication of steroid treatment. Although perioperative steroid replacement therapy is generally administered in patients undergoing pituitary surgery, there are no previous reports concerning the development of steroid psychosis after perioperative steroid replacement therapy following pituitary surgery. We herein report a case of steroid psychosis induced by perioperative steroid replacement therapy for pituitary surgery. A 35-year-old man presented with a visual disturbance that had persisted for 1 year. A magnetic resonance imaging scan showed a large pituitary tumor, and a laboratory study revealed slight dysfunction of the hypothalamo-pituitary-adrenal axis. The patient was diagnosed with a non-functioning pituitary tumor and underwent tumor resection via the endoscopic endonasal approach. The initial dose of perioperative steroid replacement therapy was 200 mg of hydrocortisone administered immediately before the operation. The replacement dose was gradually tapered and discontinued over a 7-day period. On postoperative day 4, the patient exhibited an elated mood, grandiose delusions, anxiety, and agitation. We diagnosed these psychiatric symptoms as steroid psychosis induced by steroid replacement and we prescribed risperidone as a treatment. The symptoms gradually improved and did not recur. This case highlights the risk of steroid psychosis following treatment with perioperative steroid replacement therapy for pituitary adenoma and raises questions regarding the appropriateness of perioperative steroid replacement for pituitary adenoma.

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Grüber's ligament as a useful landmark for the abducens nerve in the transnasal approach

Tomio Ryosuke, Toda Masahiro, Sutiono Agung B udi, Horiguchi Takashi, Aiso Sadakazu, Yoshida Kazunari

Journal of neurosurgery 122 ( 3 ) 499 - 503 2015.03

OBJECT: Extended endoscopic transnasal surgeries for skull base lesions have recently been performed. Some expert surgeons have attempted to remove tumors such as chordomas, meningiomas, and pituitary adenomas in the clival region using the transnasal approach and have reported abducens nerve injury as a common complication. There have been many microsurgical anatomical studies of the abducens nerve, but none of these studies has described an anatomical landmark of the abducens nerve in the transnasal approach. In this study the authors used cadaver dissections to describe Grüber's ligament as the most reliable landmark of the abducens nerve in the transnasal transclival view.METHODS: The petroclival segment of the abducens nerve was dissected in the interdural space-which is also called Dorello's canal, the petroclival venous gulf, or the sphenopetroclival venous confluence-using the transnasal approach in 20 specimens obtained from 10 adult cadaveric heads.RESULTS: The petroclival segment of the abducens nerve clearly crossed and attached to Grüber's ligament in the interdural space, as noted in the transnasal view. The average length of the dural porus to the intersection on the abducens nerve was 5.2 ± 1.0 mm. The length of the posterior clinoid process (PCP) to the intersection on Grüber's ligament was 6.4 ± 2.6 mm. The average width of Grüber's ligament at the midsection was 1.6 ± 0.5 mm.CONCLUSIONS: Grüber's ligament is considered a useful landmark, and it is visible in most adults. Thus, surgeons can find the abducens nerve safely by visualizing inferolaterally along Grüber's ligament from the PCP.

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Petrous apex cholesterol granuloma

Shibao Shunsuke, Toda Masahiro, Tomita Toshiki, Saito Katsuya, Ogawa Kaoru, Kawase Takeshi, Yoshida Kazunari

Neurologia Medico-Chirurgica 55 ( 4 ) 351 - 355 2015

ISSN 0470-8105

Recently, petrous apex cholesterol granulomas (CGs) have been treated via the endoscopic endonasal transsphenoidal approach (EEA) using a silicone tube, to prevent drainage route occlusion. Occlusion of the drainage route has led to problems with recurrence. The aim of this report is to describe the use of a surgical technique to prevent drainage route occlusion. In surgical technique, the posterolateral wall of the sphenoid sinus was opened by EEA. After cyst debridement, a vascularized nasoseptal flap with a width of approximately 4 cm was inserted into the lumen with a silicone T-tube with a diameter of 7 mm. This technique was used in two patients: the first patient during the second operation after recurrence following occlusion of the drainage route, and the second patient during the first operation. Opening of the cyst wall was confirmed endoscopically in both patients 12–24 months after surgery, even after removal of the T-tube. In conclusion, the use of a pedicled nasoseptal flap with a silicone tube is useful to prevent CG recurrence, by paranasal cavitization of the cystic cavity.

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Analysis of the intercavernous sinuses using multidetector computed tomography digital subtraction venography (CT-DSV)

Mizutani Katsuhiro, Toda Masahiro, Yoshida Kazunari

Clinical Neurology and Neurosurgery 131 31 - 34 2015

ISSN 0303-8467

Purposes The intercavernous sinuses (ICSs) connect both sides of the cavernous sinus. Knowledge of the ICSs is useful when employing the endoscopic endonasal transsphenoidal approach. Although there were some studies concerning the anatomy of ICSs using cadavers, there is no well-recognized method of the radiological evaluation of the ICSs. Therefore, we evaluate the ICSs using computed tomography digital subtraction venography (CT-DSV) in the cases of unruptured aneurysm that had the normal sellae anatomy. Methods We retrospectively analyzed 97 cases of unruptured cerebral aneurysm that had normal parasellar and sellar anatomy except for the aneurysms. The analysis was performed using the multi-planar reconstruction images obtained by CT-DSV in these cases. Results The anterior ICS (AICS), inferior ICS (IICS) and posterior ICS (PICS) were detected in 51 cases (52.6%), 28 cases (28.9%) and 76 cases (78.4%) respectively. In the cases older than 51 years old, the AICS was detected significantly less often than in those younger than 50 years old. Conclusions The CT-DSV images directly reflected the blood flow. Most of the past research on the ICSs was obtained using cadavers, which could therefore not directly assess the normal human blood flow. The present study showed the usefulness of CT-DSV for evaluating the ICSs and to understand the normal anatomy of the ICSs.

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GH-producing Pituitary Adenoma and Concomitant Rathke’s Cleft Cyst: A case report and short review.

Tamura R, Takahashi S, Emoto K, Nagashima H, Toda M, Yoshida K

Case Rep Neurol Med 2015 948025 2015

Research paper (scientific journal), Joint Work

Transoral vs. endoscopic endonasal approach for clival/upper cervical chordoma

Shidoh Satoka, Toda Masahiro, Kawase Takeshi, Nakajima Hideo, Tomita Toshiki, Ogawa Kaoru, Yoshida Kazunari

Neurologia Medico-Chirurgica 54 ( 12 ) 991 - 998 2014.12

ISSN 0470-8105

The surgical results of 18 cases of clival/upper cervical chordoma treated in the last decade via the endoscopic endonasal approach (EEA, 9 cases) and the transoral-transpalatal approach (TO-TPA, 9 cases) were compared. Each group showed the same incidence of subdural invasion, with 5 cases each. The superior (frontal base) and lateral surgical fields were wider by EEA, but the inferior view lower than the cranio-vertebral junction (CVJ) was wider by TO-TPA. Gross total removal was achieved in 3 cases in the EEA group, but in only 1 case in the TO-TPA group. Differences in radicality might be due to the extent of the lateral and subdural overview. However for large tumors extending below the CVJ, TO-TPA was the only viable approach for surgical removal. Surgical complications were higher in the EEA (4 cases) than the TO-TPA group (1 case), and were mainly caused by aggressive management of subdural invasion in the EEA group. Post-operative oral intake was earlier and the operative time was shorter in the EEA group. The surgical results were more radical and less invasive in the EEA group than the TO-TPA group. However in tumors extending below the CVJ, the surgical field in EEA was limited, indicating the need to use the transoral route or a combination of routes. A higher complication rate following subdural management was a negative factor that requires improvement in the EEA group and two-staged EEA followed by a transcranial approach may be considered for the cases with subdural invasion.

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Analysis of the bacterial flora in the nasal cavity and the sphenoid sinus mucosa in patients operated on with an endoscopic endonasal transsphenoidal approach

Shibao Shunsuke, Toda Masahiro, Tomita Toshiki, Ogawa Kaoru, Yoshida Kazunari

Neurologia Medico-Chirurgica 54 ( 12 ) 1009 - 1013 2014.12

ISSN 0470-8105

The aim of this study was to analyze the bacterial flora in the nasal cavity and sphenoid sinus and evaluate the sensitivity of these bacteria to antibiotics that can be used to prevent postoperative meningitis. Bacteria of the preoperative nasal cavity and intraoperative sphenoid sinus mucosa were cultured and analyzed in 40 patients (20 men and 20 women; mean age, 52.2 years) who underwent endoscopic transsphenoidal surgery. The sensitivity of these bacteria to cephalosporin, a representative prophylactic antibiotic, was examined. Staphylococcus epidermidis was the most frequently detected species in both spaces; 24 (38.7%) of 62 isolates in the nasal cavity and 26 (37.1%) of 70 isolates in the sphenoid sinus. In contrast, Corynebacterium species were found mainly in the nasal cavity, and anaerobic bacteria were found only in the sphenoid sinus. Bacteria that were resistant to cephalosporin were found in the nasal cavity in 3.2% of patients and in the sphenoid sinus in 20% of patients. In conclusion, the composition of bacterial flora, including bacteria that are resistant to prophylactic antibiotics, differs between the nasal cavity and the sphenoid sinus.

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Functional analysis of a novel glioma antigen, EFTUD1

Saito Katsuya, Iizuka Yukihiko, Ohta Shigeki, Takahashi Satoshi, Nakamura Kenta, Saya Hideyuki, Yoshida Kazunari, Kawakami Yutaka, Toda Masahiro

Neuro-Oncology 16 ( 12 ) 1618 - 1629 2014.12

ISSN 1522-8517

BACKGROUND: A cDNA library made from 2 glioma cell lines, U87MG and T98G, was screened by serological identification of antigens by recombinant cDNA expression (SEREX) using serum from a glioblastoma patient. Elongation factor Tu GTP binding domain containing protein 1 (EFTUD1), which is required for ribosome biogenesis, was identified. A cancer microarray database showed overexpression of EFTUD1 in gliomas, suggesting that EFTUD1 is a candidate molecular target for gliomas.METHODS: EFTUD1 expression in glioma cell lines and glioma tissue was assessed by Western blot, quantitative PCR, and immunohistochemistry. The effect on ribosome biogenesis, cell growth, cell cycle, and induction of apoptosis and autophagy in glioma cells during the downregulation of EFTUD1 was investigated. To reveal the role of autophagy, the autophagy-blocker, chloroquine (CQ), was used in glioma cells downregulating EFTUD1. The effect of combining CQ with EFTUD1 inhibition in glioma cells was analyzed.RESULTS: EFTUD1 expression in glioma cell lines and tissue was higher than in normal brain tissue. Downregulating EFTUD1 induced G1 cell-cycle arrest and apoptosis, leading to reduced glioma cell proliferation. The mechanism underlying this antitumor effect was impaired ribosome biogenesis via EFTUD1 inhibition. Additionally, protective autophagy was induced by glioma cells as an adaptive response to EFTUD1 inhibition. The antitumor effect induced by the combined treatment was significantly higher than that of either EFTUD1 inhibition or CQ alone.CONCLUSION: These results suggest that EFTUD1 represents a novel therapeutic target and that the combination of EFTUD1 inhibition with autophagy blockade may be effective in the treatment of gliomas.

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Pilocytic astrocytoma with anaplastic features presenting good long-term clinical course after surgery alone

Saito Katsuya, Toda Masahiro, Yoshida Kazunari

Child's Nervous System 2014.08

ISSN 0256-7040

Purpose Pilocytic astrocytomas (PAs) are the most common brain tumor in children and typically have an excellent prognosis. However, some PAs show histologically anaplastic features. It is reported that PAs with anaplastic features often need the postoperative radiation and chemotherapy due to aggressiveness such as early local recurrence and dissemination. We describe an interesting case of primary anaplastic PA with good clinical course in the long-term. Methods A 10-year-old man presented with worsening headache and vomiting. Magnetic resonance imaging (MRI) showed a large cystic tumor with contrast-enhanced solid component in a right occipital lobe. Magnetic resonance spectroscopy (MRS) showed the decrease of N-acetylaspartate (NAA) and the increase of choline and lipids, which suggested the malignancy. Results The patient was operated with an occipital lobectomy. The tumor was incompletely resected due to the deep invasion to the inner wall of lateral ventricle. Pathological diagnosis was a pilocystic astrocytoma with anaplastic features. Although aggressive features were suspected from magnetic resonance spectroscopy and pathological findings, the remnant tumor showed no recurrence for 8 years without any postoperative treatments. Conclusion PAs could exhibit variable behavior, and careful managements including wait-and-scan should be considered, because adjuvant therapies may cause child's growth disorder and malignant transformation. © 2014 Springer-Verlag Berlin Heidelberg.

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Anterior petrosal approach

Tomio Ryosuke, Toda Masahiro, Yoshida Kazunari, Borghei-Razavi Hamid

Journal of Neurosurgery 120 ( 5 ) 1249 - 1250 2014

ISSN 0022-3085

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Primary dural closure and anterior cranial base reconstruction using pericranial and nasoseptal multi-layered flaps in endoscopic-assisted skull base surgery

Tomio Ryosuke, Toda Masahiro, Tomita Toshiki, Yazawa Masaki, Kono Maya, Ogawa Kaoru, Yoshida Kazunari

Acta Neurochirurgica 156 ( 10 ) 1911 - 1915 2014

ISSN 0001-6268

Introduction: Dural and anterior cranial base reconstruction is essential in the surgical resection of a craniofacial tumor that extends from the paranasal sinuses to the subdural space. Watertight reconstruction of vascularized tissue is essential to prevent postoperative liquorrhea, especially under conditions that prevent wound healing (e.g., postoperative irradiation therapy).Method: We successfully treated two cases of olfactory neuroblastoma by endoscopic-assisted craniotomy with primary dural closure and anterior cranial base reconstruction using a multi-layered flap technique. Dural defects were closed using temporal fascia or fascia lata in a conventional fashion, immediately after detaching the subdural tumor, in order to isolate and prevent contamination of subdural components and cerebrospinal fluid (CSF) from the tumor and nasal sinuses. Tumor removal and anterior cranial base reconstruction were performed without any concern of CSF contamination after dural closure by craniotomy and endoscopic endonasal approach (EEA). Vascularized pericranial flaps (PCF) and nasoseptal flaps (NSF) were used simultaneously as doubled-over layers for reconstruction.Results: The tumor was completely removed macroscopically and the anterior cranial base was reconstructed in both cases. CSF leak and postoperative meningitis were absent. Postoperative and irradiation therapy courses were successful and uneventful.Conclusions: This multi-layered anterior cranial base reconstruction consisted of three layers: a fascia for dural plasty and double-layered PCF and NSF. This surgical reconstruction technique is suitable to treat craniofacial tumors extending into the subdural space through the anterior cranial base dura mater.

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Isolated Pituitary Tuberculoma - Case Reports –

Saito K, Toda M, Shido S, Tomita T, Ogawa K, Yoshida K.

NMC Case Report Journal 2013 ( 0330 ) 2014

Research paper (scientific journal), Joint Work

Sox6 Up-Regulation by Macrophage Migration Inhibitory Factor Promotes Survival and Maintenance of Mouse Neural Stem/Progenitor Cells

Ohta Shigeki, Misawa Aya, Lefebvre Véronique, Okano Hideyuki, Kawakami Yutaka, Toda Masahiro

PLoS ONE 8 ( 9 ) 2013.09

Macrophage migration inhibitory factor (MIF) has important roles in supporting the proliferation and/or survival of murine neural stem/progenitor cells (NSPCs), but downstream effectors remain unknown. We show here that MIF robustly increases the expression of Sox6 in NSPCs in vitro. During neural development, Sox6 is expressed in the ventricular zone of the ganglionic eminence (GE) of mouse brains at embryonic day 14.5 (E14.5), cultured NSPCs from E14.5 GE, and NSPCs in the subventricular zone (SVZ) around the lateral ventricle (LV) of the adult mouse forebrain. Retroviral overexpression of Sox6 in NSPCs increases the number of primary and secondary neurospheres and inhibits cell differentiation. This effect is accompanied with increased expression of Hes1 and Bcl-2 and Akt phosphorylation, thus suggesting a role for Sox6 in promoting cell survival and/or self-renewal ability. Constitutive activation of the transcription factor Stat3 results in up-regulation of Sox6 expression and chromatin immunoprecipitation analysis showed that MIF increases Stat3 binding to the Sox6 promoter in NSPCs, indicating that Stat3 stimulates Sox6 expression downstream of MIF. Finally, the ability of MIF to increase the number of primary and secondary neurospheres is inhibited by Sox6 gene silencing. Collectively, our data identify Sox6 as an important downstream effector of MIF signaling in stemness maintenance of NSPCs. © 2013 Ohta et al.

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Infratentorial low-grade oligoastrocytoma with aggressive clinical behavior in an adult

Sano Keisho, Toda Masahiro, Sasaki Hikaru, Kitamura Yohei, Mikami Shuji, Hirato Junko, Inoue Satoshi, Kawase Takeshi, Yoshida Kazunari

Brain Tumor Pathology 30 ( 2 ) 99 - 103 2013.04

ISSN 1433-7398

Oligoastrocytoma preferentially arises in the cerebral hemisphere, and a cerebellar location is unusual. We report the case of a 35-year-old woman with an aggressive cerebellar tumor histopathologically diagnosed as oligoastrocytoma World Health Organization (WHO) grade II. After partial removal of the tumor, she underwent concomitant temozolomide (TMZ) therapy with local irradiation followed by additional TMZ monotherapy. However, her symptoms gradually worsened, and chronological magnetic resonance imaging showed remarkable tumor enlargement. In accordance with the aggressive clinical course, unfavorable genetic characteristics such as the gain of the entire chromosome 7, loss of 9p, absence of 1p/19q codeletion, absence of methylation of the O6- methylguanine-deoxyribonucleic acid methyltransferase promoter, and absence of the isocitrate dehydrogenase-1 mutation were observed. The present case illustrates that these molecular characteristics represent the biological features of gliomas more closely than the histopathological diagnosis and may also suggest that infratentorial gliomas arise through a distinct tumorigenic pathway from their supratentorial counterparts. © The Japan Society of Brain Tumor Pathology 2012.

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Our experience in anterior petrosal approach. Letter to the editor.

Tomio R, Borghei-Razavi H, Toda M, Yoshida K.

J Neurosurg 2013

Research paper (scientific journal), Joint Work

Transoral-transpalatal approach and endoscopic endonasal approach for chordomas of the craniovertebral junction

Shidoh S, Toda M, Nakajima H, Tomita T, Ogawa K, Kawase T, Yoshida K

J Neurophysiol 4 ( 4 ) 162 2013

Research paper (scientific journal), Joint Work, Accepted

Macrophage migration inhibitory factor (MIF) promotes cell survival and proliferation of neural stem/progenitor cells

Ohta Shigeki, Misawa Aya, Fukaya Raita, Inoue Satoshi, Kanemura Yonehiro, Okano Hideyuki, Kawakami Yutaka, Toda Masahiro

Development (Cambridge) 139 ( 19 ) 2012.10

ISSN 0950-1991

In a previous study, we showed that murine dendritic cells (DCs) can increase the number of neural stem/progenitor cells (NSPCs) in vitro and in vivo. In the present study, we identified macrophage migration inhibitory factor (MIF) as a novel factor that can support the proliferation and/or survival of NSPCs in vitro. MIF is secreted by DCs and NSPCs, and its function in the normal brain remains largely unknown. It was previously shown that in macrophages, MIF binds to a CD74-CD44 complex. In the present study, we observed the expression of MIF receptors in mouse ganglionic-eminence-derived neurospheres using flow cytometry in vitro. We also found CD74 expression in the ganglionic eminence of E14 mouse brains, suggesting that MIF plays a physiological role in vivo. MIF increased the number of primary and secondary neurospheres. By contrast, retrovirally expressed MIF shRNA and MIF inhibitor (ISO-1) suppressed primary and secondary neurosphere formation, as well as cell proliferation. In the neurospheres, MIF knockdown by shRNA increased caspase 3/7 activity, and MIF increased the phosphorylation of Akt, Erk, AMPK and Stat3 (Ser727), as well as expression of Hes3 and Egfr, the products of which are known to support cell survival, proliferation and/or maintenance of NSPCs. MIF also acted as a chemoattractant for NSPCs. These results show that MIF can induce NSPC proliferation and maintenance by multiple signaling pathways acting synergistically, and it may be a potential therapeutic factor, capable of activating NSPC, for the treatment of degenerative brain disorders. © 2012. Published by The Company of Biologists Ltd.

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Epidural anterior petrosectomy with subdural visualization of sphenobasal vein via the anterior transpetrosal approach-technical case report

Ichimura Shinya, Yoshida Kazunari, Kagami Hiroshi, Inaba Makoto, Orii Maaya, Kitamura Yohei, Saga Isako, Toda Masahiro

Neurosurgical Review 35 ( 4 ) 609 - 613 2012.10

ISSN 0344-5607

The drainage of the superficialmiddle cerebral vein (SMCV) is classified into four subtypes. The sphenobasal vein (SBV) drains from the SMCV to the pterygoid venous plexus at the temporal skull base. Epidural procedures in the standard anterior transpetrosal approach (ATPA) may damage the route of the SBV. We report a case in which modified surgical procedures via the ATPA were used to preserve the SBV. A 45-year-old man complained of right facial pain. Magnetic resonance images revealed a right cerebellopontine tumor suggestive of an epidermoid cyst. Right carotid angiography revealed that the SMCV drained into the pterygoid venous plexus via the SBV. The convexity dura mater of the temporal lobe was cut and the anterior part of the temporal lobe was retracted subdurally. The SBV was visualized from the subdural side. The basal dura mater of the temporal lobe posterior to the SBV was cut and the posterior part of the temporal lobe was retracted epidurally. After dissecting the dura mater medial to the greater petrosal nerve and to the edge of the petrous apex, the petrous apex was exposed and drilled out without injuring the SBV. The superior petrous sinus and the tentorium were cut. The tumor compressed the root exit zone of the trigeminal nerve. The tumor was grossly totally removed. ThemodifiedATPA (epidural anterior petrosectomy with subdural visualization of the SBV) is effective in preserving the SBV. © Springer-Verlag 2012.

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Application of the endoscopic transsphenoidal approach to true type transsellar transsphenoidal meningoencephalocele in an adult

Saito Katsuya, Toda Masahiro, Sano Keisho, Tomita Toshiki, Ogawa Kaoru, Yoshida Kazunari

Acta Neurochirurgica 154 ( 8 ) 1511 - 1515 2012.08

ISSN 0001-6268

Of the transsellar transsphenoidalmeningoencephaloceles (TTSMEs), the true type presents with the hernial sac extending from the intracranium to the epipharynx through the sellar floor. The true type is the most serious and difficult to manage, especially when the hernial sac contains vital structures, such as the anterior cerebral artery, pituitary gland, optic nerve, hypothalamus, and third ventricle. Surgical outcome for true type TTSME is reported to be poor. We describe a successful case of endoscopic repair for a 36-year-old man with true type TTSME. Our success with endoscopic repair for true type TTSME in an adult is the first reported case. We believe that the endoscopic transsphenoidal approach allows less invasive surgery and provides an acceptable operative outcome in comparison with other microsurgical approaches. © Springer-Verlag 2012.

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Surgical results of an endoscopic endonasal approach for clival chordomas

Saito Katsuya, Toda Masahiro, Tomita Toshiki, Ogawa Kaoru, Yoshida Kazunari

Acta Neurochirurgica 154 ( 5 ) 879 - 886 2012.05

ISSN 0001-6268

Background The surgical approaches for clival chordomas remain controversial, although the extent of resection is one of the most important factors for long survival rates. Recently an endoscopic endonasal approach in good collaboration with otolaryngologists has attracted major attention as a surgical approach for clival chordomas. We describe our experience with the endoscopic endonasal approach and provide a review of the literature. Methods Between 2008 and 2011, six operations were performed via the endoscopic endonasal approach for clivus chordomas. The mean tumor size was 35 mm in diameter. The tumor location was mainly from the upper to middle clivus. The tumor extended into the cavernous sinus in five cases and intradurally in three cases. A binostril approach was performed in four cases, while a one nostril approach was performed in two cases. Results Gross total removal was achieved in three cases. The analysis of cases with incomplete resection suggested that residual tumors were observed epidurally and subdurally. The residual on the epidura was observed from the posterior clinoid to the posterior compartment of the cavernous sinus. On the other hand, the residual on the subdural was observed behind the upper part of the pituitary gland. There was no postoperative cerebrospinal fluid (CSF) leakage using vascularized nasoseptal flaps in any of the cases. Conclusions The endoscopic endonasal transclival approach allows an appropriate extent of resection with acceptable complication rates in comparison with other approaches. In our series, the accomplishment of gross total removal was associated with the relationship between the tumors and surrounding structures, such as the pituitary gland and the cavernous portion of the intracranial carotid artery (ICA). © Springer-Verlag 2012.

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Downregulation of KIF23 suppresses glioma proliferation

Takahashi Satoshi, Fusaki Noemi, Ohta Shigeki, Iwahori Yoshihiro, Iizuka Yukihiko, Inagawa Kohei, Kawakami Yutaka, Yoshida Kazunari, Toda Masahiro

Journal of Neuro-Oncology 106 ( 3 ) 519 - 529 2012.02

ISSN 0167-594X

To identify therapeutic molecular targets for glioma, we performed modified serological identification of antigens by recombinant complementary DNA (cDNA) expression cloning using sera from a mouse glioma model. Two clones, kinesin family member 23 (Kif23) and structural maintenance of chromosomes 4 (Smc4), were identified as antigens through immunological reaction with sera from mice harboring synergic GL261 mouse glioma and intratumoral inoculation with a mutant herpes simplex virus. The human Kif23 homolog KIF23 is a nuclear protein that localizes to the interzone of mitotic spindles, acting as a plus-end-directed motor enzyme that moves antiparallel microtubules in vitro. Expression analysis revealed a higher level of KIF23 expression in glioma tissues than in normal brain tissue. The introduction of small interfering RNA (siRNA) targeting KIF23 into two different glioma cell lines, U87MG and SF126, downregulated KIF23 expression, which significantly suppressed glioma cell proliferation in vitro. KIF23 siRNA-treated glioma cells exhibited larger cell bodies with two or more nuclei compared with control cells. In vivo analysis using mouse xenograft showed that KIF23 siRNA/DNA chimeratreated tumors were significantly smaller than tumors treated with control siRNA/DNA chimera. Taken together, our results indicate that downregulation of KIF23 decreases proliferation of glioma cells and that KIF23 may be a novel therapeutic target in malignant glioma. © 2011 Springer Science+Business Media, LLC.

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Macrophage migration inhibitory factor (MIF) promotes cell survival and proliferation of neural stem/progenitor cells.

Ohta S, Misawa A, Fukaya R, Inoue S, Kanemura Y, Okano H, Kawakami Y, Toda M

J Cell Sci 125 3210 - 3220 2012

Research paper (scientific journal), Joint Work, Accepted

Downregulation of uPARAP mediates cytoskeletal rearrangements and decreases invasion and migration properties in glioma cells

Takahashi Satoshi, Yamada-Okabe Hisafumi, Hamada Kenji, Ohta Shigeki, Kawase Takeshi, Yoshida Kazunari, Toda Masahiro

Journal of Neuro-Oncology 103 ( 2 ) 267 - 276 2011.06

ISSN 0167-594X

To identify molecular therapeutic targets for glioma, we performed gene expression profiling by using a complementary DNA (cDNA) microarray method and identified the urokinase plasminogen activator receptor-associated protein (uPARAP/Endo180) as a gene expressed highly in glioma tissue compared with the normal brain tissue. The uPARAP is an endocytic receptor for collagen. In certain cell types, uPARAP occurs in a complex with the urokinase plasminogen activator receptor (uPAR) where it fulfills other functions in addition to collagenolysis. Quantitative PCR analysis using a cDNA panel revealed higher expression levels of uPARAP in glioma tissue compared with normal brain tissue. Western blot analysis revealed that the uPARAP protein was expressed in glioma samples and two glioma cell lines, KNS42 and KNS81, but not expressed in control tissue from the normal brain. Introduction of small interfering RNA-targeted uPARAP into the two different glioma cell lines, KNS42 and KNS81, resulted in downregulation of uPARAP expression, and it significantly suppressed glioma cell migration and invasion in vitro. Control glioma cells showed small cell bodies, whereas uPARAP siRNA-treated glioma cells exhibited large and flat morphology. Most of the polymeric actin in the control glioma cells was concentrated in the lamellipodia that are observed in mobile cells. In contrast, in the uPARAP siRNA-treated glioma cells, polymeric actin became organized in stress fibers and the lamellipodia disappeared, characteristic of immobile cells. Our present study suggests that uPARAP may be involved in glioma cell invasiveness through actin cytoskeletal rearrangement. downregulation of uPARAP may be a novel anti-invasion therapeutic strategy for malignant gliomas. © 2010 Springer Science+Business Media, LLC.

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Functional analysis of HOXD9 in human gliomas and glioma cancer stem cells

Tabuse Masanao, Ohta Shigeki, Ohashi Yohei, Fukaya Raita, Misawa Aya, Yoshida Kazunari, Kawase Takeshi, Saya Hideyuki, Thirant Cécile, Chneiweiss Hérve, Matsuzaki Yumi, Okano Hideyuki, Kawakami Yutaka, Toda Masahiro

Molecular Cancer 10 2011.05

Background: HOX genes encode a family of homeodomain-containing transcription factors involved in the determination of cell fate and identity during embryonic development. They also behave as oncogenes in some malignancies.Results: In this study, we found high expression of the HOXD9 gene transcript in glioma cell lines and human glioma tissues by quantitative real-time PCR. Using immunohistochemistry, we observed HOXD9 protein expression in human brain tumor tissues, including astrocytomas and glioblastomas. To investigate the role of HOXD9 in gliomas, we silenced its expression in the glioma cell line U87 using HOXD9-specific siRNA, and observed decreased cell proliferation, cell cycle arrest, and induction of apoptosis. It was suggested that HOXD9 contributes to both cell proliferation and/or cell survival. The HOXD9 gene was highly expressed in a side population (SP) of SK-MG-1 cells that was previously identified as an enriched-cell fraction of glioma cancer stem-like cells. HOXD9 siRNA treatment of SK-MG-1 SP cells resulted in reduced cell proliferation. Finally, we cultured human glioma cancer stem cells (GCSCs) from patient specimens found with high expression of HOXD9 in GCSCs compared with normal astrocyte cells and neural stem/progenitor cells (NSPCs).Conclusions: Our results suggest that HOXD9 may be a novel marker of GCSCs and cell proliferation and/or survival factor in gliomas and glioma cancer stem-like cells, and a potential therapeutic target. © 2011 Tabuse et al; licensee BioMed Central Ltd.

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Adjuvant effects of formalin-inactivated HSV through activation of dendritic cells and inactivation of myeloid-derived suppressor cells in cancer immunotherapy

Ohkusu-Tsukada Kozo, Ohta Shigeki, Kawakami Yutaka, Toda Masahiro

International Journal of Cancer 128 ( 1 ) 119 - 131 2011.01

ISSN 0020-7136

Use of adequate adjuvant is necessary for induction of effective antitumor immune responses. To develop an effective adjuvant for cancer immunotherapy, we selected formalin-inactivated (f)-HSV as an adjuvant component, and analyzed the mechanisms underlying its adjuvant effects. First, we found that f-HSV can induce the tumor antigen-specific CTLs by enhancing antigen cross-presentation by dendritic cells (DCs), mainly through TLR2, but not TLR9. Next, f-HSV was also found to prevent the accumulation of myeloid-derived suppressor cells (MDSCs). We demonstrated that the expansion of MDSCs in the blood and spleen during tumor progression required B cells producing the inflammatory angiogenesis factors, vascular endothelial growth factor (VEGF)-A and neuropilin-1 (NRP-1), a co-receptor for VEGF receptor-2 (VEGFR-2). Interestingly, the transmembrane-type NRP-1 on B cells changed to soluble-type NRP-1 (sNRP-1) by f-HSV treatment. We further showed that the sNRP-1 and VEGF-A secreted from B cells by f-HSV treatment could abrogate the immunosuppressive ability of MDSCs. These results suggest that f-HSV can enhance antitumor immune responses as an adjuvant, not only through activation of DCs, but also inactivation of MDSCs via B cells. © 2010 UICC.

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A simple behavioral test for locomotor function after brain injury in mice

Tabuse Masanao, Yaguchi Masae, Ohta Shigeki, Kawase Takeshi, Toda Masahiro

Journal of Clinical Neuroscience 17 ( 11 ) 1412 - 1416 2010.11

ISSN 0967-5868

To establish a simple and reliable test for assessing locomotor function in mice with brain injury, we developed a new method, the rotarod slip test, in which the number of slips of the paralytic hind limb from a rotarod is counted. Brain injuries of different severity were created in adult C57BL/6 mice, by inflicting 1-point, 2-point and 4-point cryo-injuries. These mice were subjected to the rotarod slip test, the accelerating rotarod test and the elevated body swing test (EBST). Histological analyses were performed to assess the severity of the brain damage. Significant and consistent correlations between test scores and severity were observed for the rotarod slip test and the EBST. Only the rotarod slip test detected the mild hindlimb paresis in the acute and sub-acute phase after injury. Our results suggest that the rotarod slip test is the most sensitive and reliable method for assessing locomotor function after brain damage in mice. © 2010 Elsevier Ltd. All rights reserved.

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Subtemporal approach - Venous drainage and surgical anatomy

Toda Masahiro, Yoshida Kazunari, Kawase Takeshi

Japanese Journal of Neurosurgery 19 ( 10 ) 742 - 752 2010.10

ISSN 0917-950X

Because the temporal lobe extends deeply into the middle cranial fossa anteriorly, the procedure of the subtemporal approach should be modified so as to avoid damaging the brain and the cortical veins by compression with retractors. To minimize compression damage to the temporal lobe it is necessary to perform the craniotomy along the middle cranial fossa, and to remove the zygomatic arch for supratentorial lesions, and to remove the petrous pyramid for infratentorial lesions. An extradural approach is useful as a means of preventing damage to bridging veins including Labbe's vein, but because the superior petrosal sinus and the tentorium are transected in the procedure by the anterior transpetrosal approach, the drainage pathways of the superficial sylvian vein (especially the sphenobasal vein and the sphenopetrosal vein) should be checked preoperatively. In this article we outline the surgical anatomy of the middle cranial fossa required for the subtemporal approach and variations in the venous drainage of the superficial sylvian vein, and then we describe the treatment of petroclival lesions by the anterior transpetrosal approach.

Endoscopic skull base surgery

Toda Masahiro

Neurological Surgery 38 ( 6 ) 506 - 514 2010.06

ISSN 0301-2603

Identification of antigen against brain tumor stem cell and application for treatment of glioma

Toda Masahiro

Gan to kagaku ryoho. Cancer & chemotherapy 37 ( 6 ) 1016 - 1018 2010.06

ISSN 0385-0684

Isolation of cancer stem-like cells from a side population of a human glioblastoma cell line, SK-MG-1

Fukaya Raita, Ohta Shigeki, Yamaguchi Masayuki, Fujii Hirofumi, Kawakami Yutaka, Kawase Takeshi, Toda Masahiro

Cancer Letters 291 ( 2 ) 150 - 157 2010.05

ISSN 0304-3835

Accumulating evidence suggests that in several types of brain tumors, including glioma, only a phenotypic subset of tumor cells called brain cancer stem cells (BCSCs) may be capable of initiating tumor growth. Recently, the isolation of side population (SP) cells using Hoechst dye has become a useful method for obtaining cancer stem cells in various tumors. In this study, we isolated cancer stem-like cells from human glioma cell lines using the SP technique. Flow cytometry analysis revealed that SK-MG-1, a human glioblastoma cell line, contained the largest number of SP cells among the five glioma cell lines that were analyzed. The SP cells had a self-renewal ability and were capable of forming spheres in a neurosphere culture medium containing EGF and FGF2. Spheres derived from the SP cells differentiated into three different lineage cells: neurons, astrocytes and oligodendrocytes. RT-PCR analysis revealed that the SP cells expressed a neural stem cell marker, Nestin. The SP cells generated tumors in the brains of NOD/SCID mice at 8 weeks after implantation, whereas the non-SP cells did not generate any tumors in the brain. These results indicate that SP cells isolated from SK-MG-1 possess the properties of cancer stem cells, including their self-renewal ability, multi-lineage differentiation, and tumorigenicity. Therefore, the SP cells from SK-MG-1 may be useful for analyzing BCSCs because of the ease with which they can be handled and their yield. © 2009 Elsevier Ireland Ltd. All rights reserved.

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Targeted inhibition of IL-10-secreting CD25^- Treg via p38 MAPK suppression in cancer immunotherapy

Ohkusu-Tsukada Kozo, Toda Masahiro, Udono Heiichiro, Kawakami Yutaka, Takahashi Kimimasa

European Journal of Immunology 40 ( 4 ) 1011 - 1021 2010.04

ISSN 0014-2980

Cancer-induced immunotolerance mediated by inducible Treg (iTreg) is a major obstacle to cancer immunotherapy. In a basic study of immunotolerance, injection of an endogenous superantigen, i.e. the minor lymphocyte stimulatory (Mls)-1^a, into specific TCR Vβ8.1-Tg mice enabled generation of anergic CD25^- iTreg, the immunosuppressive function of which was maintained by IL-10 production via p38-MAPK activation. Interestingly, although p38-chemical inhibitor (p38-inhibitor) is capable of breaking CD25^- iTreg-induced immunotolerance, the p38-inhibitor had hardly any immunotolerance breaking effect when CD25⁺ Treg were present, suggesting that depletion of CD25⁺ Treg is necessary for p38-inhibitor to be effective. Peptide OVA_323-339 iv.-injection into its specific TCR-Tg (OT-II) mice also induced adaptive tolerance by iTreg. Peptide immunotherapy with p38-inhibitor after CD25⁺ Treg-depletion was performed in an OVA-expressing lymphoma E.G7-bearing tolerant model established by adoptive transfer of OT-II CD25^- iTreg, which resulted in suppression of tumor growth. Similarly, the antitumor immunity induced by peptide immunotherapy in colon carcinoma CT26-bearingmice, in which the number of IL-10-secreting iTreg is increased, was augmented by treatment with p38-inhibitor after CD25 ⁺ Treg-depletion and resulted in inhibition of tumor progression. These results suggest that simultaneous inhibition of two distinct Treg-functions may be important to the success of cancer immunotherapy. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

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Identification of HLA-A2- And A24-restricted T-cell epitopes derived from SOX6 expressed in glioma stem cells for immunotherapy

Ueda Ryo, Ohkusu-Tsukada Kozo, Fusaki Noemi, Soeda Akio, Kawase Takeshi, Kawakami Yutaka, Toda Masahiro

International Journal of Cancer 126 ( 4 ) 919 - 929 2010.02

ISSN 0020-7136

Malignant gliomas are the most aggressive human primary brain tumors and are currently incurable. Immunotherapies have the potential to target glioma and glioma stem cells (GSCs) that are resistant to conventional therapies. We previously identified SOX6 as a human glioma antigen and demonstrated that vaccination with SOX6 DNA induced cytotoxic T lymphocytes (CTLs) specific for glioma, thereby exerting therapeutic antitumor responses in glioma-bearing mice. In this study, we attempted to identify SOX6-derived peptides as specific targets for effective and safe T-cell-mediated immunotherapy targeting SOX6-positive glioma and GSCs. In vitro stimulation with human leukocyte antigen (HLA)-A*2402 (A24)-restricted peptides, RFENLGPQL (SOX6₅₀₄) and PYYEEQARL (SOX6₆₂₈) or the HLA-A*0201 (A2)-restricted peptide, ALFGDQDTV (SOX6₄₄₇) was capable of inducing SOX6 peptide-specific CTLs in peripheral blood mononuclear cells derived from healthy donors and glioma patients. These CTLs were able to lyse a majority of glioma cell lines and a GSC line derived from human glioblastoma in an HLA Class I-restricted and an antigen-dependent manner. Furthermore, peptide vaccines of SOX6₆₂₈, which was conserved in the murine SOX6 protein and expected to bind to major histocompatibility complex (MHC) H-2^d, induced CTLs specific for SOX6₆₂₈ in H-2^d mice. Normal autologous cells from mice, in which SOX6-specific immune responses were generated, were not destroyed. These results suggest that these SOX6 peptides are potnetially immunogenic in HLA-A24 or -A2 positive glioma patients and should be considered as a promising strategy for safe and effective T-cell-based immunotherapy of patients with gliomas. © 2009 UICC.

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Immunotherapy targeted at brain cancer stem cells

Toda Masahiro

Open Cancer Immunology Journal 3 48 - 50 2010

Progress in stem cell research has been associated with the discovery of the presence of cancer stem cells in a variety of malignant tumors, and because these cells are resistant to anticancer agents and radiotherapy, analysis of their properties has been rapidly pursued as an important target for the treatment of cancers, including malignant brain tumors. Brain cancer stem cells (BCSCs) have been isolated from brain tumor tissue and brain tumor cell lines by using neural stem cell culture methods. Analyzing the properties of BCSCs is extremely important to developing treatment methods that target BCSCs. Although no treatment method targeting BCSCs has yet been established, several methods have been proposed based on their cell-biological characteristics. This article describes therapeutic strategies that target drug-resistance molecules and stem-cell-associated molecules as well as immunotherapy targeted at BCSCs. © Masahiro Toda; Licensee Bentham Open.

Transplantation of dendritic cells promotes functional recovery from spinal cord injury in common marmoset

Yaguchi Masae, Tabuse Masanao, Ohta Shigeki, Ohkusu-Tsukada Kozo, Takeuchi Tamaki, Yamane Junichi, Katoh Hiroyuki, Nakamura Masaya, Matsuzaki Yumi, Yamada Masayuki, Itoh Toshio, Nomura Tatsuji, Toyama Yoshiaki, Okano Hideyuki, Toda Masahiro

Neuroscience Research 65 ( 4 ) 384 - 392 2009.12

ISSN 0168-0102

We previously reported that implantation of dendritic cells (DCs) into the injured site activates neural stem/progenitor cells (NSPCs) and promotes functional recovery after spinal cord injury (SCI) in mice. Working toward clinical application of DC therapy for SCI, we analyzed whether DCs promote functional recovery after SCI in a non-human primate, the common marmoset (CM). CMs are usually born as dizygotic twins. They are thus natural bone marrow and peripheral blood chimeras due to sharing of the placental circulation between dizygotic twins, leading to functional immune tolerance. In this study, to identify adequate CM donor-and-host pairs, mixed leukocyte reaction (MLR) assays were performed. Then, CM-DCs were generated from the bone marrow of the twin selected to be donor and transplanted into the injured site of the spinal cord of the other twin selected to be host, 7 days after injury. Histological analyses revealed fewer areas of demyelination around the injured site in DC-treated CMs than in controls. Immunohistochemical analysis showed that more motor neurons and corticospinal tracts were preserved after SCI in DC-treated CMs. Motor functions were evaluated using three different behavior tests and earlier functional recovery was observed in DC-treated CMs. These results suggest DC therapy to possibly be beneficial in primates with SCI and that this treatment has potential for clinical application. © 2009 Elsevier Ireland Ltd and the Japan Neuroscience Society.

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Therapeutic strategies targeting brain tumor stem cells

Toda Masahiro

Brain and Nerve 61 ( 7 ) 799 - 803 2009.07

ISSN 1881-6096

Progress in stem cell research reveals cancer stem cells to be present in a variety of malignant tumors. Since they exhibit resistance to anticancer drugs and radiotherapy, analysis of their properties has been rapidly carried forward as an important target for the treatment of intractable malignancies, including brain tumors. In fact, brain cancer stem cells (BCSCs) have been isolated from brain tumor tissue and brain tumor cell lines by using neural stem cell culture methods and isolation methods for side population (SP) cells, which have high drug-efflux capacity. Although the analysis of the properties of BCSCs is the most important to developing methods in treating BCSCs, the absence of BCSC purification methods should be remedied by taking it up as an important research task in the immediate future. Thus far, there are no effective treatment methods for BCSCs, and several treatment methods have been proposed based on the cell biology characteristics of BCSCs. In this article, I outline potential treatment methods damaging treatment-resistant BCSCs, including immunotherapy which is currently a topic of our research.

Activation of dendritic-like cells and neural stem/progenitor cells in injured spinal cord by GM-CSF

Hayashi Kaori, Ohta Shigeki, Kawakami Yutaka, Toda Masahiro

Neuroscience Research 64 ( 1 ) 96 - 103 2009.05

ISSN 0168-0102

Previously, we demonstrated that implanted dendritic cells (DCs) in the injured spinal cord of adult mice exert a neurotrophic effect, resulting in the activation of endogenous neural stem/progenitor cells (NSPCs) and neurogenesis. Granulocyte-macrophage colony stimulating factor (GM-CSF), which is an essential cytokine for the generation of DCs from haematopoietic progenitor cells, has been shown to be beneficial for the treatment of spinal cord injury (SCI). In the present study, to evaluate the mechanisms underlying this therapeutic efficacy of GM-CSF, we investigated the effects of GM-CSF on the DC-like cells and NSPCs in the injured spinal cord. When GM-CSF was injected into the injured spinal cords of mice, the numbers of DC-like cells and activated microglia/macrophages around the lesion site increased, accompanied by an increase in BDNF expression. A significant increase in endogenous NSPCs was observed around the lesion site in the GM-CSF-treated mice compared with that in the controls. A neurosphere forming assay revealed that GM-CSF also induced the proliferation of NSPCs in vitro. Moreover, injection of GM-CSF into the lesion immediately after the SCI resulted in early recovery of the locomotor function of the injured mice. In conclusion, GM-CSF activated DC-like cells and NSPCs in the injured spinal cord, which was probably involved in its beneficial effects in cases of spinal cord injury. © 2009 Elsevier Ireland Ltd and the Japan Neuroscience Society.

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Intraoperative navigation and fluorescence imagings in malignant glioma surgery

Toda Masahiro

Keio Journal of Medicine 57 ( 3 ) 155 - 161 2008.09

ISSN 0022-9717

The current basic goals in glioma surgery are radical tumor resection without triggering the development of new neurological deficits. Although complete removal of malignant gliomas is extremely difficult because of the tumors' infiltrative characteristics, gross total resection of the tumor is known to be associated with improved outcome in the patients. To enable safe and radical resection of malignant gliomas, especially those adjacent to eloquent brain areas, rapid progress has been made in the development of operative support techniques; e.g., navigation systems to provide information about the anatomical and functional locations in the brain and a fluorescence imaging technique for differentiating brain tumors from normal brain tissue. These intraoperative imaging techniques in glioma surgery have improved the functional outcomes of glioma patients.

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Functional recovery after spinal cord injury in mice through activation of microglia and dendritic cells after IL-12 administration

Yaguchi Masae, Ohta Shigeki, Toyama Yoshiaki, Kawakami Yutaka, Toda Masahiro

Journal of Neuroscience Research 86 ( 9 ) 1972 - 1980 2008.07

ISSN 0360-4012

We have previously reported that the transplantation of dendritic cells (DCs) brings about functional recovery after spinal cord injury in mice through the activation of endogenous microglia/macrophages and neural stem/progenitor cells. In this study, the effect of interleukin-12 (IL-12), which is secreted from DCs, was evaluated for the treatment of spinal cord injury in mice. Administration of IL-12 into the injured site significantly increased the number of activated microglia/macrophages and DCs as well as the expression of brain-derived neurotrophic factor surrounding the lesion site. Immunohistochemical analyses showed that de novo neurogenesis and remyelination were induced by IL-12 treatment. Furthermore, an open field test using Basso-Beattie-Brenham scoring revealed a significant improvement of locomotor function in mice treated with IL-12. These results suggest that IL-12 administration into the injured spinal cord results in a functional recovery through the activation of microglia/macrophages and DCs. © 2008 Wiley-Liss, Inc.

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Induction of protective and therapeutic antitumor immunity by a DNA vaccine with a glioma antigen, SOX6

Ueda Ryo, Kinoshita Eiko, Ito Rena, Kawase Takeshi, Kawakami Yutaka, Toda Masahiro

International Journal of Cancer 122 ( 10 ) 2274 - 2279 2008.05

ISSN 0020-7136

We previously reported identifying SOX6 as a glioma antigen by serological screening using a testis cDNA library. Its preferential expression and frequent IgG responses in glioma patients indicate that SOX6 may be a useful target for immunotherapy. To examine whether cytotoxic T-lymphocyte (CTL) responses specific for SOX6 to destroy glioma can be generated in vivo, we treated glioma-bearing mice by vaccination with a plasmid DNA encoding murine full-length SOX6 protein. Following SOX6-DNA vaccination, CTLs specific for SOX6-expressing glioma cells were induced, while normal autologous-cells that had restrictedly expressed SOX6 during embryogenesis were not destroyed. Furthermore, DNA vaccination with SOX6 exerted protective and therapeutic antitumor responses in the glioma-bearing mice. This antitumor activity was abrogated by the depletion of CD4 positive T cells and/or CD8 positive T cells. These results suggest that the SOX6 protein has multiple CTL and helper epitopes to induce antitumor activity and the effectiveness of SOX6-DNA vaccine for the prevention and treatment of glioma. © 2008 Wiley-Liss, Inc.

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Isolation and characterization of dendritic cells from common marmosets for preclinical cell therapy studies

Ohta Shigeki, Ueda Yoko, Yaguchi Masae, Matsuzaki Yumi, Nakamura Masaya, Toyama Yoshiaki, Tanioka Yoshikuni, Tamaoki Norikazu, Nomura Tatsuji, Okano Hideyuki, Kawakami Yutaka, Toda Masahiro

Immunology 123 ( 4 ) 566 - 574 2008.04

ISSN 0019-2805

Dendritic cells (DCs) have important functions as modulators of immune responses, and their ability to activate T cells is of great value in cancer immunotherapy. The isolation of DCs from the peripheral blood of rhesus and African green monkeys has been reported, but the immune system in the common marmoset remains poorly characterized, although it offers many potential advantages for preclinical studies. In the present study, we devised methods, based on techniques developed for mouse and human DC preparation, for isolating DCs from three major tissue sources in the common marmoset: bone marrow (BM), spleen and peripheral blood. Each set of separated cells was analysed using the cell surface DC-associated markers CD11c, CD80, CD83, CD86 and human leucocyte antigen (HLA)-DR, all of which are antibodies against human antigens, and the cells were further characterized both functionally and morphologically as antigen-presenting cells. BM proved to be an excellent cell source for the isolation of DCs intended for preclinical studies on cell therapy, for which large quantities of cells are required. In the BM-derived CD11c⁺ cell population, cells exhibiting the characteristic features of DCs were enriched, with the typical DC morphology and the abilities to undergo endocytosis, to secrete interleukin (IL)-12, and to stimulate Xenogenic T cells. Moreover, BM-derived DCs produced the neurotrophic factor NT-3, which is also found in murine splenic DCs. These results suggest that BM-derived DCs from the common marmoset may be useful for biological analysis and for preclinical studies on cell therapy for central nervous system diseases and cancer. © 2007 Blackwell Publishing Ltd.

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Identification of a neuron-specific human gene, KIAA1110, that is a guanine nucleotide exchange factor for ARF1

Hattori Yujiro, Ohta Shigeki, Hamada Kenji, Yamada-Okabe Hisafumi, Kanemura Yonehiro, Matsuzaki Yumi, Okano Hideyuki, Kawakami Yutaka, Toda Masahiro

Biochemical and Biophysical Research Communications 364 ( 4 ) 737 - 742 2007.12

ISSN 0006-291X

To identify neuron-specific genes, we performed gene expression profiling, cDNA microarray and in silico ESTs (expressed sequence tags) analyses. We identified a human neuron-specific gene, KIAA1110 (homologue of rat synArfGEF (Po)), that is a member of the guanine nucleotide exchange factor (GEF) for the ADP-ribosylation factor (ARF). RT-PCR analysis showed that the KIAA1110 gene was expressed specifically in the brain among adult human tissues, whereas no apparent expression was observed in immature neural tissues/cells, such as fetal brain, glioma tissues/cells, and neural stem/precursor cells (NSPCs). The KIAA1110 protein was shown to be expressed in mature neurons but not in undifferentiated NSPCs. Immunohistochemical analysis also showed that KIAA1110 was expressed in neurons of the human adult cerebral cortex. Furthermore, the pull-down assay revealed that KIAA1110 has a GEF activity toward ARF1 that regulates transport along the secretion pathway. These results suggest that KIAA1110 is expressed specifically in mature neurons and may play an important role in the secretion pathway as a GEF for ARF1. © 2007 Elsevier Inc. All rights reserved.

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Preferential expression and frequent IgG responses of a tumor antigen, SOX5, in glioma patients

Ueda Ryo, Yoshida Kazunari, Kawase Takeshi, Kawakami Yutaka, Toda Masahiro

International Journal of Cancer 120 ( 8 ) 1704 - 1711 2007.04

ISSN 0020-7136

We previously reported to identify SOX5 as a glioma antigen by serological screening using a testis cDNA library. The present study was designed to analyze SOXS expression, its immunoreactivity, and the correlation between SOX5 IgG responses and clinical features in glioma patients to evaluate the possibility of its use as a diagnostic marker. Quantitative RT-PCR and Western blot analysis revealed that SOX5 was expressed in glioma tissues, but not in normal adult tissues, except in the testis. An immunohistochemical analysis showed that SOX5 was expressed in glioma cells, but only a few SOX5-positive cells were detected in non-neoplastic tissues from the cerebral cortex. IgG antibodies against SOX5 were detected in sera from 8 of the 27 glioma patients (27.6%), 0 of the 14 patients with other brain diseases (0%), 1 of the 54 other cancer patients (1.9%) and 1 of the 37 healthy individuals (2.7%). Patients with glioblastotna (GBM) who showed IgG responses against SOX5 exhibited significantly better survival periods than GBM patients without SOX5 antibodies. In summary, SOX5 is aberrantly expressed in glioma and can be recognized as a glioma antigen using IgGs from the sera of glioma patients. Furthermore, there is a statistically significant correlation between the presence of SOX5 IgGs and survival in GBM patients, suggesting that the glioma antigen SOX5 may be useful not only as a diagnostic marker, but also as a prognostic marker in glioma patients. © 2007 Wiley-Liss, Inc.

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Enhancement of immunologic tumor regression by intratumoral administration of dendritic cells in combination with cryoablative tumor pretreatment and Bacillus Calmette-Guerin cell wall skeleton stimulation

Udagawa Masaru, Kudo-Saito Chie, Hasegawa Go, Yano Kazuhito, Yamamoto Aiko, Yaguchi Masae, Toda Masahiro, Azuma Ichiro, Iwai Takehisa, Kawakami Yutaka

Clinical Cancer Research 12 ( 24 ) 7465 - 7475 2006.12

ISSN 1078-0432

Purpose: We developed an effective immunotherapy, which could induce antitumor immune responses against shared and unique tumor antigens expressed in autologous tumors. Experimental Design: Intratumoral administration of dendritic cells is one of the individualized immunotherapies; however, the antitumor activity is relatively weak. In this study, we attempted to enhance the antitumor efficacy of the i.t. dendritic cell administration by combining dendritic cells stimulated with Bacillus Calmette-Guerin cell wall skeleton (BCG-CWS) additionally with cryoablative pretreatment of tumors and analyzed the therapeutic mechanisms. Results: These two modifications (cryoablation of tumors and BCG-CWS stimulation of dendritic cells) significantly increases the antitumor effect on both the treated tumor and the untreated tumor, which was distant at the opposite side, in a bilateral s.c. murine CT26 colon cancer model. Further analysis of the augmented antitumor effects revealed that the cryoablative pretreatment enhances the uptake of tumor antigens by the introduced dendritic cells, resulting in the induction of tumor-specific CD8⁺ T cells responsible for the in vivo tumor regression of both treated and remote untreated tumors. This novel combination i.t. dendritic cell immunotherapy was effective against well-established large tumors. The antitumor efficacy was further enhanced by depletion of CD4⁺CD25 ⁺FoxP3⁺ regulatory T cells. Conclusions: This novel dendritic cell immunotherapy with i.t. administration of BCG-CWS-treated dendritic cells following tumor cryoablation could be used for the therapy of cancer patients with multiple metastases. © 2006 American Association for Cancer Research.

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Intracarotid injection of granulocyte-macrophage colony-stimulating factor induces neuroprotection in a rat transient middle cerebral artery occlusion model

Nakagawa Toru, Suga Sadao, Kawase Takeshi, Toda Masahiro

Brain Research 1089 ( 1 ) 179 - 185 2006.05

ISSN 0006-8993

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was found to promote collateral flow in patients with coronary artery disease and also to induce arteriogenesis in a rat hypoperfusion brain model. Activated macrophages have been shown to induce vascular proliferation and play an important role in ischemic stroke. In this study, we examined the therapeutic effect of GM-CSF on the ischemic brain by activating microglia/macrophages. Rats were subjected to 1-h intraluminal middle cerebral artery occlusion (MCAO) and received an intracarotid injection of GM-CSF (5 ng) or saline immediately after reperfusion. Infarct volume, neurological function and histological findings were assessed 48 h later. An intracarotid injection of GM-CSF reduced the infarct volume and improved neurological function at 48 h after reperfusion. Histological analysis revealed that the number of activated microglia/macrophages to be increased and the number of apoptotic cells to be decreased in the area of the penumbra. These results suggest that intracarotid injection of GM-CSF may have a therapeutic effect on brain ischemia via activation of microglia/macrophages. © 2006 Elsevier B.V. All rights reserved.

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Identification of a glioma antigen, GARC-1, using cytotoxic T lymphocytes induced by HSV cancer vaccine

Iizuka Yukihiko, Kojima Hidefumi, Kobata Tetsuji, Kawase Takeshi, Kawakami Yutaka, Toda Masahiro

International Journal of Cancer 118 ( 4 ) 942 - 949 2006.02

ISSN 0020-7136

Despite several ongoing clinical trials of immunotherapies against glioma, few glioma-specifk antigens recognized by cytotoxic T lymphocytes (CTLs) have been identified. We recently demonstrated that intratumoral inoculation with herpes simplex virus (HSV) as a cancer vaccine activates tumor-specific CTLs. To identify glioma antigens recognized by CTLs, we used the HSV cancer vaccine to vaccinate mice harboring a syngeneic mouse glioma cell line, GL261. From the splenocytes of the immunized mice, we generated an H-2D^b-restricted CTL line, GCL-1, that was specific for GL261. Then, a cDNA expression library generated from GL261 was screened with GCL-1, and a new gene encoding glioma antigen, GARC-1, was isolated. Sequence analysis revealed that the GARC-1 gene isolated from GL261 had a point mutation causing an amino acid change (Asp to Asn at position 81). T-cell epitope analysis revealed that the mutated peptide GARC-1_77-85 (AALLNKLYA) but not the wild-type peptide (AALLDKLYA), was recognized by GCL-1. These results suggest that HSV cancer vaccination may be a useful method for inducing tumor-specific CTLs and identifying tumor antigens. Furthermore, this GL261/GARC-1 murine glioma model may be useful for the development of immunotherapy for brain tumors. © 2005 Wiley-Liss, Inc.

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Identification of glioma-specific RFX4-E and -F isoforms and humoral immune response in patients

Matsushita Hirokazu, Uenaka Akiko, Ono Toshiro, Hasegawa Kosei, Sato Shuichiro, Koizumi Fumihito, Nakagawa Kazuhiko, Toda Masahiro, Shingo Tetsuro, Ichikawa Tomotsugu, Noguchi Yuji, Tamiya Takashi, Furuta Tomohisa, Kawase Takeshi, Date Isao, Nakayama Eiichi

Cancer Science 96 ( 11 ) 801 - 809 2005.11

ISSN 1347-9032

For regulatory factor X4 (RFX4), two alternatively spliced variants, RFX4-A and -B, were reported in the testis. In this study, we identified transcript variants RFX4-C, -D, -E, and -F, and demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) that RFX4-A, -B and -C mRNAs were expressed only in the testis, and RFX4-D mRNA was expressed only in normal brain tissues. In tumors, RFX4-E and -F in addition to RFX4-D mRNA were expressed in gliomas by rapid amplification of cDNA ends and RT-PCR analyses. Expression of RFX4 mRNA was not observed in other tumors, such as lung, esophageal, stomach, colon or liver cancers. Quantitative real-time RT-PCR using common primer pairs detecting all of the variant transcripts showed high expression in normal testis, low expression in the brain (1% compared to the expression in testis), and overexpression in 17 of 61 gliomas (28%). Western blot analysis using DC28 monoclonal antibody (mAb) produced against recombinant RFX4-D C-terminus protein showed expression of RFX4-A and -C proteins, but not RFX4-B protein, in the testis, and expression of RFX4-D protein in the brain. Moreover, expression of RFX4-E and -F proteins, but not RFX4-D protein, was observed in gliomas. Immunohistochemistry analysis using DC28 mAb showed positive staining in the nuclei of spermatocytes in the testis and glioma cells. Antibody against RFX4 was detected in the sera of 3 of 58 (5%) glioma patients by enzyme-linked immunosorbent assay, suggesting the immunogenicity of RFX4-E and -F proteins in glioma patients. © Japanese Cancer Association.

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Gene therapy for brain tumors using herpes simplex virus vector

Toda Masahiro

Nippon rinsho. Japanese journal of clinical medicine 63 Suppl 9 510 - 514 2005

ISSN 0047-1852

Identification of an epigenetically silenced gene, RFX1, in human glioma cells using restriction landmark genomic scanning

Ohashi Yohei, Ueda Masakazu, Kawase Takeshi, Kawakami Yutaka, Toda Masahiro

Oncogene 23 ( 47 ) 7772 - 7779 2004.10

ISSN 0950-9232

To identify the CpG islands differentially methylated in human glioma, we performed restriction landmark genomic scanning with a CpG methylation-sensitive enzyme. We found 12 spots, the intensity of which was entirely lost or decreased in both the human glioma tissues examined as compared with that in matched normal lymphocytes, indicating aberrant methylation of these CpG islands in gliomas. The expression of RFX1, one of the genes associated with the methylated CpG islands, was frequently decreased in human glioma cell lines and tissues. We also demonstrated that the isolated CpG island located in the seventh intron of the RFX1 gene had enhancer activity and was hypermethylated in all of the glioma tissues and cell lines analysed, but not in normal brains or lymphocytes. Treatment of glioma cells with a demethylating agent, 5-azacytidine, resulted in the expression of RFX1, indicating that the silencing of the RFX1 gene may be attributable to its methylation. RFX1 has been implicated in transcriptional downregulation of the proto-oncogene c-myc. By expression of the RFX1 gene, the cellular proliferative activity of glioma cells was suppressed. Taken together, these results suggest that the RFX1 gene may be epigenetically silenced in human gliomas and involved in glioma tumorigenesis.

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Identification of human tumor antigens and its implications for diagnosis and treatment of cancer

Kawakami Yutaka, Fujita Tomonobu, Matsuzaki Yuriko, Sakurai Toshiharu, Tsukamoto Makoto, Toda Masahiro, Sumimoto Hidetoshi

Cancer Science 95 ( 10 ) 784 - 791 2004.10

ISSN 1347-9032

Human tumor antigens recognized by T cells have been identified by means of various molecular biological and immunological methods, including cDNA expression cloning with patients' T cells and antibodies, cDNA subtraction using RDA and PCR differential display, systematic gene analysis such as DNA sequencing, CGH, DNA chip/microarray and SAGE, in vitro T cell induction and immunization of HLA transgenic mice. The identification of human tumor antigens has led to a better understanding of the nature of tumor antigens, anti-tumor immune responses in patients before and after immunotherapy, and tumor escape mechanisms. The information obtained from these researches has enabled us to develop and improve immunotherapy by attempting to overcome the identified problems, including intrinsically low immunogenicity of tumor antigens and several escape mechanisms, such as regulatory T cell induction. The existence of immunogenic unique antigens derived from genetic alterations in tumor cells, and the varied immunogenicity of shared tumor antigens among patients due to differing expression in tumor cells and immunoreactivity of patients, indicates that individualized immunotherapy should ideally be performed. The identified antigens will also be useful for development of diagnostic methods and molecular targeting therapy for cancer.

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Implantation of Dendritic Cells in Injured Adult Spinal Cord Results in Activation of Endogenous Neural Stem/Progenitor Cells Leading to De Novo Neurogenesis and Functional Recovery

Mikami Yuji, Okano Hideyuki, Sakaguchi Masanori, Nakamura Masaya, Shimazaki Takuya, Okano Hirotaka James, Kawakami Yutaka, Toyama Yoshiaki, Toda Masahiro

Journal of Neuroscience Research 76 ( 4 ) 453 - 465 2004.05

ISSN 0360-4012

We report a treatment for spinal cord injury involving implantation of dendritic cells (DCs), which act as antigen-presenting cells in the immune system. The novel mechanisms underlying this treatment produce functional recovery. Among the immune cells tested, DCs showed the strongest activity inducing proliferation and survival of neural stem/progenitor cells (NSPCs) in vitro. Furthermore, in DC-implanted adult mice, endogenous NSPCs in the injured spinal cord were activated for mitotic de novo neurogenesis. These DCs produced neurotrophin-3 and activated endogenous microglia in the injured spinal cord. Behavioral analysis revealed the locomotor functions of DC-implanted mice to have recovered significantly as compared to those of control mice. Our results suggest that DC-implantation exerts trophic effects, including activation of endogenous NSPCs, leading to repair of the injured adult spinal cord. © 2004 Wiley-Liss, Inc.

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Augmentation of Antitumor Immune Responses by Multiple Intratumoral Inoculations of Replication-Conditional HSV and Interleukin-12

Iizuka Yukihiko, Suzuki Ayuko, Kawakami Yutaka, Toda Masahiro

Journal of Immunotherapy 27 ( 2 ) 92 - 98 2004.03

ISSN 1524-9557

Intratumoral inoculation with a herpes simplex virus (HSV) mutant, G207, as an in situ cancer vaccine has been shown to inhibit tumor growth by inducing tumor-specific immune responses. Here, as a step toward the clinical application of this therapeutic approach, we evaluated different protocols for enhancing the antitumor effect. First, in a bilaterally established tumor model with CT26 colon carcinoma, we demonstrated that multiple intratumoral inoculations with G207 induced a greater antitumor effect on both the inoculated and distant tumors than did 1 or 2 inoculations. Second, to boost this antitumor effect, we developed 2 strategies: multiple in situ cancer vaccines with G207 in combination with systemic administration of recombinant interleukin-12 (rIL-12) (G207/systemic rIL-12) or local administration of rIL-12 (G207/local rIL-12). The antitumor effects in both the inoculated and distant tumors by the combined treatments were significantly greater than by either G207 or rIL- 12 treatment alone. G207/systemic rIL-12 and G207/local rIL-12 mediated the complete regression of both the inoculated and distant tumors in 67% and 79% of the animals, respectively. These results indicate that multiple intratumoral inoculations of G207 and systemic or local rIL- 12 administration work synergistically to facilitate tumor regression and that this combination of treatments may have potential for treating cancer metastasis.

Identification of a human glioma antigen, SOX6, recognized by patients' sera

Ueda Ryo, Iizuka Yukihiko, Yoshida Kazunari, Kawase Takeshi, Kawakami Yutaka, Toda Masahiro

Oncogene 23 ( 7 ) 1420 - 1427 2004.02

ISSN 0950-9232

To identify tumor antigens for glioma, a human testis cDNA library was screened by serological identification of antigens by recombinant expression cloning with sera from glioma patients. In this screening, the most frequently isolated antigen was SOX6, an Sry-related high-mobility group (HMG) box-containing gene. SOX6 is a transcriptional factor that is specifically expressed in the developing central nervous system and in the early stages of chondrogenesis in mouse embryos. IgG antibodies against SOX6 were detected in sera from 12 of 36 glioma patients (33.3%), 0 of 14 patients with other brain disease (0%), and one of 54 other cancer patients (1.9%). In sera from 37 healthy individuals, no IgG responses against SOX6 were detected, except in an elderly female. Furthermore, Western blot and ELISA analyses with sera from glioma patients revealed that the DNA-binding domain, the HMG box of SOX6, might be a dominant epitope of IgGs against SOX6. RT-PCR and Northern blot analysis revealed that the SOX6 gene was more highly expressed in glioma tissues than in normal adult tissues, except testis. Western blot analysis with an anti-SOX6 antibody demonstrated that the SOX6 protein was expressed in glioma tissues, but not in normal adult brain tissue. Immunohistochemical analysis with the anti-SOX6 antibody showed that all the glioma tissues analysed expressed SOX6 in tumor cells, but only a few SOX6-positive cells were detected in non-neoplastic tissues from the cerebral cortex. In summary, these results indicate that the developmentally regulated transcription factor SOX6 is aberrantly expressed in glioma and specifically recognized by IgGs from glioma patients' sera.

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Expression of a transcriptional factor, SOX6, in human gliomas

Ueda Ryo, Yoshida Kazunari, Kawakami Yutaka, Kawase Takeshi, Toda Masahiro

Brain Tumor Pathology 21 ( 1 ) 35 - 38 2004

ISSN 1433-7398

By screening a human testis cDNA library with glioma patients' sera, we isolated a transcriptional factor, SOX6. Here, we analyzed SOX6 expression in gliomas having a range of malignancy grades using immunostaining. Murine Sox6 is a transcriptional factor that is specifically expressed in the developing central nervous system and in the early stages of chondrogenesis in mouse embryos. The reverse transcription-polymerase chain reaction (RT-PCR) revealed that the SOX6 gene was more highly expressed in glioma tissues and fetal brain than in normal adult brain and other cancer cells, except melanoma cells. Immunohistochemical analysis with the anti-SOX6 antibody showed that all the glioma tissues analyzed (14 glioblastomas, 14 anaplastic astrocytomas, 3 anaplastic oligoastrocytomas, 5 diffuse astrocytomas, 1 oligodendroglioma, and 1 pilocytic astrocytoma) expressed SOX6 in tumor cells, but only a few SOX6-positive cells were detected in nonneoplastic tissues from the cerebral cortex. These results indicate that the developmentally regulated transcription factor SOX6 may be a potential diagnostic marker for gliomas.

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Immunohistochemical analysis of SOX6 expression in human brain tumors

Ueda Ryo, Yoshida Kazunari, Kawakami Yutaka, Kawase Takeshi, Toda Masahiro

Brain Tumor Pathology 21 ( 3 ) 117 - 120 2004

ISSN 1433-7398

We previously demonstrated that the developmentally regulated gene, SOX6, is strongly expressed in glioma cells and in the fetal brain, but only faintly in the normal adult brain. Recent studies have indicated that brain tumor cells may share antigens, signaling systems, and behavior with neural stem/progenitor cells. To test the validity of this proposition, we analyzed the expression of SOX6 in various human central nervous system (CNS) tumors. Immunohistochemical analysis revealed that astrocytic and oligodendroglial tumors expressed SOX6; neuronal-glial cell tumors (central neurocytoma) and embryonal tumors (medulloblastoma), which arise from multipotential stem cell precursors, also showed a high intensity of SOX6 staining. In contrast, ependymal tumors (ependymoma and subependymoma), meningioma, and schwannoma, which are all well differentiated tumors, showed either no staining or only faint staining for SOX6. These results suggest that SOX6 may be expressed in bipotential or multipotential cells capable of neuronal and glial differentiation, but not in fully differentiated cells. SOX6 may be a useful marker for the diagnosis of tumors arising from immature bipotential cells that may differentiate into neuronal and glial cells.

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Immuno-viral therapy as a new approach for the treatment of brain tumors

Toda Masahiro

Drug News and Perspectives 16 ( 4 ) 223 - 229 2003.05

ISSN 0214-0934

The central nervous system (CNS) has been considered an immunologically privileged site; however, recent evidence suggests that activated T cells cross the intact blood-brain barrier and that a series of immunological events is initiated when T cells recognize CNS antigens. Therefore, brain tumors might be selectively eliminated by T cells activated with antigens specific for the tumors. Using a conditionally replicating herpes simplex virus-1 (HSV-1) mutant, G207, we developed a novel therapeutic approach for metastatic brain tumors that combines viral therapy with immunotherapy. G207 replicates selectively within tumor cells and causes tumor cell destruction without local or systemic toxicity, because its replication in normal cells is highly attenuated. Furthermore, the inoculation of tumors outside the CNS with G207 induces systemic immune responses not only to HSV but also to tumor antigens. In our strategy, in which both the metastatic brain tumor and the primary tumor outside the CNS are inoculated with G207, the HSV-infected brain tumor can be eliminated by the combined effects of the direct oncolysis and the induced anti-HSV and antitumor T cells. Recently, the safety of directly inoculating the human brain with G207 has been shown. These results indicate that our therapeutic approach using G207 may hold promise for the treatment of metastatic brain tumors. © 2003 Prous Science. All rights reserved.

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In situ cancer vaccination with a replication-conditional HSV for the treatment of liver metastasis of colon cancer

Endo Takashi, Toda Masahiro, Watanabe Masahiko, Iizuka Yukihiko, Kubota Tetsuro, Kitajima Masaki, Kawakami Yutaka

Cancer Gene Therapy 9 ( 2 ) 142 - 148 2002

ISSN 0929-1903

In this study, we investigated the therapeutic efficacy of a replication-conditional mutant HSV, G207, for the treatment of liver metastasis of colon carcinoma. Three liver metastasis models in syngeneic BALB/c mice were developed: (i) splenic injection, (ii) splenic and subcutaneous (s.c.) injection, and (iii) orthotopic implantation of CT26 colon carcinoma. In the splenic injection model, G207 was injected into the established splenic tumor on day 7. In the splenic and s.c. injection model, G207 were injected into the established s.c. tumor on days 5 and 8. In the orthotopic implantation model, a piece of CT26 tumor tissue was transplanted onto the wall of the cecum and G207 was injected in the established cecum tumor on day 7. On day 21 or 28, animals were sacrificed and liver metastases were evaluated. In all three models in immunocompetent mice, liver metastases were significantly reduced by intratumoral inoculation with G207 compared to the control. In athymic mice, however, there was no significant therapeutic effect of intratumoral inoculation with G207 on liver metastases. Tumor-specific cytotoxic T-lymphocyte responses were induced in mice treated with G207 in the orthotopic implantation model. These results suggest that intratumoral inoculation of G207, as an in situ cancer vaccine, can be an effective approach against liver metastasis of colon cancer and the efficacy involves tumor-specific T-cell responses.

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A simple and reliable behavioral analysis of locomotor function after spinal cord injury in mice

Mikami Yuji, Toda Masahiro, Watanabe Masahiko, Nakamura Masaya, Toyama Yoshiaki, Kawakami Yutaka

Journal of Neurosurgery 97 ( 1 SUPPL. ) 142 - 147 2002

ISSN 0022-3085

To establish a simple and reliable method to assess the behavioral function after spinal cord injury (SCI) in mice, the authors used an automated animal movement analysis system, SCANET. Two different SCI lesions were created in adult female BALB/c and C57BL/6 mice by transecting both the posterior columns and the left lateral and anterior funiculi or only the left lateral and anterior funiculi at T-8. Control mice underwent laminectomy only. The SCANET system consists of a cage equipped with two crossing sensor frames arranged at different heights, by which small (MI) and large (M2) horizontal movements and the vertical movement involved in rearing (RG) can be monitored. The authors assessed locomotor function by determining the M1, M2, and RG scores; to this end, they used the SCANET system and a previously established behavior test, the 21-point open-field Basso-Beattie-Bresnahan (BBB) Locomotor Rating Scale. The results indicated that the RG scores were significantly and consistently different between the spinal cord-injured and control mice, irrespective of the mouse strain or injury model, but that MI and M2 scores were not. Moreover, there was a statistically positive correlation between the RG score and the BBB Scale score. For the assessment of locomotor function after SCI, use of the SCANET sytem in behavioral analysis is simple and the method is highly reproducible. The analysis of vertical movement is useful for assessing the recovery of limb function in mice following thoracic hemisection.

Immuno-viral therapy of brain tumors by combination of viral therapy with cancer vaccination using a replication-conditional HSV

Toda Masahiro, Iizuka Yukihiko, Kawase Takeshi, Uyemura Keiichi, Kawakami Yutaka

Cancer Gene Therapy 9 ( 4 ) 356 - 364 2002

ISSN 0929-1903

Here we developed an effective therapeutic approach using a replication-conditional mutant of herpes simplex virus (HSV), G207, for the treatment of metastatic tumors in the immunologically privileged central nervous system. An experimental model of brain metastasis was developed using BALB/c mice that harbored both intracranial (i.c.) and subcutaneous (s.c.) mouse CT26 colon adenocarcinoma tumors. Intratumoral injections of G207 into s.c. tumors elicited cytotoxic T-cell responses not only to HSV but also to a tumor antigen; however, only a limited antitumor effect was observed on metastatic brain tumors. To improve this antitumor effect, G207 was also injected into the brain tumor. After intratumoral injections of G207 into both i.c. and s.c. CT26 tumors, a significant antitumor effect was observed in the metastatic brain tumors. This therapeutic efficacy was absent in athymic mice, indicating that the antitumor effect could be mediated by T cells. Cytotoxic T-cell responses to HSV and the tumor antigen were induced by injections of G207 into i.c. and s.c. CT26 tumors. These results suggest that HSV-infected brain tumors may be efficiently eliminated by the induced anti-HSV T cells as well as by antitumor T cells. Therefore, this strategy of immuno-viral therapy, involving direct viral oncolytic activities and inducing antitumor and antiviral immune responses, may be useful for the treatment of tumors in the immunologically privileged central nervous system.

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Increase of oligodendrocyte progenitor cells after spinal cord injury

Ishii Ken, Toda Masahiro, Nakai Yoko, Asou Hiroaki, Watanabe Masahiko, Nakamura Masaya, Yato Yoshiyuki, Fujimura Yoshikazu, Kawakami Yutaka, Toyama Yoshiaki, Uyemura Keiichi

Journal of Neuroscience Research 65 ( 6 ) 500 - 507 2001.09

ISSN 0360-4012

The reaction of oligodendrocyte progenitor cells (OPCs) after spinal cord injury (SCI) is poorly understood. In this study, we examined oligodendroglial reactions after contusion SCI in adult rats by immunohistochemistry. OPCs were identified by staining with monoclonal antibodies (mAbs) A2B5 and O4. Each of the A2B5-, O4-positive OPCs and galactocerebroside-positive oligodendrocytes dramatically increased in the lesion of the dorsal posterior funiculus. Bromodeoxyuridine (BrdU) incorporation studies showed that most O4-positive cells in the lesion were labeled with BrdU, suggesting that these OPCs were proliferative. In contrast, the expression of myelin basic protein was decreased in the lesion compared with controls that received laminectomy only. From the injured cord, OPCs were isolated by immunopanning with mAb A2B5. We observed an increased number of OPCs from the injured spinal cords compared with those isolated from controls and unoperated animals. After several days in culture, the OPCs from the lesion expressed galactocerebroside. These results suggest that OPCs are induced and can differentiate following SCI in the adult rat. © 2001 Wiley-Liss, Inc.

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Combination suicide/cytokine gene therapy as adjuvants to a defective herpes simplex virus-based cancer vaccine

Toda M., Martuza R. L., Rabkin S. D.

Gene Therapy 8 ( 4 ) 332 - 339 2001

ISSN 0969-7128

We have used syngeneic, established bilateral subcutaneous tumor models to examine the antitumor activity of herpes simplex virus (HSV) vectors, including the induction of an immune response against non-inoculated distant tumors. In such a model with CT26 murine colon adenocarcinoma, unilateral intratumoral inoculation of replication-deficient HSV-1 tsK inhibited the growth of both the inoculated and noninoculated established tumors. To enhance this limited antitumor immune response, we generated a defective HSV vector, dvIL12-tk encoding both interleukin-12 (IL-12) and HSV thymidine kinase (TK), with tsK as the helper virus. In a 'suicide gene' strategy, ganciclovir (GCV) treatment after intratumoral inoculation of dvlacZ-tk/tsK, encoding E. coli lacZ instead of IL-12, resulted in enhanced antitumor activity. Antitumor activity was also enhanced by local expression of IL-12 from dvIL-12-tk/tsK. The combination of IL-12 cytokine therapy with GCV treatment was the most efficacious approach, with significantly greater inhibition of tumor growth than IL-12 or TK + GCV alone. These results illustrate the power of combining different cancer therapy approaches; 'suicide gene' therapy, cytokine therapy, and HSV vector infection. HSV vectors are particularly well suited to this because they can accommodate the insertion of large and multiple gene sequences.

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Expression of the neural RNA- binding protein Musashi1 in human gliomas

Toda Masahiro, Iizuka Yukihiko, Yu Wangjie, Imai Takao, Ikeda Eiji, Yoshida Kazunari, Kawase Takeshi, Kawakami Yutaka, Okano Hideyuki, Uyemura Keiichi

GLIA 34 ( 1 ) 1 - 7 2001

ISSN 0894-1491

Tumor cells arising from a particular tissue may exhibit the same gene expression patterns as their precursor cells. To test this proposition, we have analyzed the expression of a neural RNA-binding protein, Musashi1, in primary human central nervous system (CNS) tumors. In rodents, Musashi1 is expressed predominantly in proliferating multipotent neural precursor cells, but not in newly generated postmitotic neurons. The expression of Musashi1 is downregulated with the successive progression of neurogenesis. In normal adult human tissues, we detected low levels of Musashi1 expression in brain and testis by RT-PCR analysis. In an RNA panel of 32 cancer tissues and cell lines, elevated expression of Musashi1 was seen in all five malignant gliomas studied, in contrast to the slight expression seen in other tumor cells, including those in several melanomas and a prostate cancer. Western blot analysis showed strong Musashi1 expression in malignant gliomas compared with nonneoplastic brain tissue. Glioblastomas, the most malignant form of glioma, showed higher Musashi1 expression than less malignant gliomas by immunohistochemical analysis. Tumors with strong Musashi1 expression tended to have high proliferative activity. Thus, the expression of Musashi1 correlated with the grade of the malignancy and proliferative activity in gliomas. These results suggest that primary CNS tumors may share gene expression patterns with primitive, undifferentiated CNS cells and that Musashi1 may be a useful marker for the diagnosis of CNS tumors. © 2001 Wiley-Liss, Inc.

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Tumor growth inhibition by intratumoral inoculation of defective herpes simplex virus vectors expressing granulocyte - Macrophage colony-stimulating factor

Toda Masahiro, Martuza Robert L., Rabkin Samuel D.

Molecular Therapy 2 ( 4 ) 324 - 329 2000.10

ISSN 1525-0016

To evaluate the potential of defective herpes simplex virus (HSV) amplicon vectors as in vivo cytokine gene transfer vehicles for active immunotherapy, we generated a defective HSV vector that encodes the murine granulocyte - macrophage colony-stimulating factor (GM-CSF) gene, using a replication-defective HSV as helper virus. A variety of murine tumor cell lines were efficiently infected in vitro with the defective GM-CSF vector (dvGM), and this led to the synthesis and secretion of murine GM-CSF. In an established bilateral subcutaneous tumor model with Harding-Passey murine melanoma, unilateral intratumoral inoculation of dvGM significantly inhibited tumor growth of both the inoculated and noninoculated contralateral tumors. This tumor inhibition was dose-dependent and resulted in increased survival of the dvGM-treated mice. Inoculation of a lacZ-expressing defective vector had no effect on tumor growth. We conclude that this defective HSV vector system offers an effective method for cytokine gene delivery in vivo and that GM-CSF expression in tumors has antitumor activity.

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Comparison of Fas- versus perforin-mediated pathways of cytotoxicity in TCR- and Thy-1-activated murine T cells

Kojima Hidefumi, Toda Masahiro, Sitkovsky Michail V.

International Immunology 12 ( 3 ) 365 - 374 2000

ISSN 0953-8178

T cell-mediated cytotoxicity can be triggered by cross-linking of TCR or Thy-1 surface proteins. While the TCR-triggered signaling initiates both perforin- and Fas ligand (FasL)-Fas-mediated mechanisms of cytotoxicity, it was not clear which mechanism was utilized by Thy-1-triggered signals and which pathway of cytotoxicity was triggered at low levels of antigen expression. It is shown that glycophosphatidylinositol-linked surface glycoprotein Thy-1 preferentially activates FasL-Fas- but not perforin-mediated cytotoxicity. This is explained by the lesser intensity of Thy-1-mediated signaling in T cells. The data suggest that Thy-1-triggered Fas-mediated cytotoxicity is completely dependent on cross-talk between Thy-1 and TCR signals since mutations in TCR-CD3 complex molecules or inhibition of tyrosine kinases or calcineurin abolished or strongly inhibited Thy-1-triggered FasL-Fas-mediated cytotoxicity. Lower concentrations of antigenic peptide or levels of cross-linking with anti-TCR-CD3 mAb are required to trigger Fas-mediated than perforin-mediated cytotoxicity by different cytotoxic T lymphocyte (CTL) lines and clones, and it is shown that cross-linking of Thy-1 is much less efficient in triggering accumulation of second messengers (intracellular Ca²⁺) than cross-linking of TCR on CTL. Taken together, these data reflect the possibility of differential activation of FasL and/or perforin pathways of cytotoxicity depending on the nature of activating stimuli and surface receptor.

Suppression of an actin-binding protein, drebrin, by antisense transfection attenuates neurite outgrowth in neuroblastoma B104 cells

Toda Masahiro, Shirao Tomoaki, Uyemura Keiichi

Developmental Brain Research 114 ( 2 ) 193 - 200 1999.05

ISSN 0165-3806

Drebrins, actin-binding proteins, are dominantly expressed during embryogenesis and accumulated in neurite processes of postmigratory neurons. While the cytoskeletal proteins are the important factors for regulating neurite outgrowth, the cellular mechanism in neurons is still unclear. To address the role of drebrins in the neurite outgrowth, we have studied the effect of suppression of drebrin on a rat neuroblastoma B104 cell line, which constitutively expresses drebrin. Deprivation of serum or addition of gangliosides in the culture medium induced remarkable neurite outgrowth of B104 cells. We transfected B104 cells with an antisense construct of human drebrin E cDNA and found that the drebrin expression was significantly reduced in the stable antisense cell lines. In response to serum deprivation and gangliosides treatment, their ability to extend neurite processes was significantly attenuated. In contrast, the cell proliferation of the antisense transfectants was arrested by serum deprivation similar to control B104 cells. These data suggest that the drebrins are required for neurite outgrowth in neuronal cells.

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Herpes simplex virus as an in situ cancer vaccine for the induction of specific anti-tumor immunity

Toda Masahiro, Rabkin Samuel D., Kojima Hidefumi, Martuza Robert L.

Human Gene Therapy 10 ( 3 ) 385 - 393 1999.02

ISSN 1043-0342

The success of cancer gene therapy is likely to require the targeting of multiple antitumor mechanisms. One strategy involves the use of attenuated, replication-competent virus vectors, such as herpes simplex virus type 1 (HSV-1) mutant G207, which is able to replicate in human tumor cells with resultant cell death and tumor growth inhibition, yet is nonpathogenic in normal tissue. In this study, we demonstrate that infection of established tumors with G207 also induces a highly specific systemic anti-tumor immune response. In a syngeneic, bilateral established subcutaneous tumor model, with mouse CT26 colorectal carcinoma cells in BALB/c mice or M3 melanoma cells in DBA/2 mice, unilateral intratumoral inoculation with G207 caused a significant reduction in the growth of both the inoculated and contralateral noninoculated tumors. This elicited anti-tumor response is dependent on viral infection of the tumor, as intradermal inoculation of G207 in BALB/c mice had no effect on CT26 tumor growth. Treatment of subcutaneous CT26 tumors by intratumoral inoculation of G207 induced a tumor-specific T cell response, CD8⁺ cytotoxic T lymphocyte (CTL) activity was generated that recognized a dominant 'tumor-specific' major histocompatibility complex (MHC) class I-restricted epitope (AH1) from CT26 cells. In immune-competent animals, G207 is acting as an in situ tumor vaccine. Therefore, intratumoral G207 inoculation is able to inhibit tumor growth both by local cytotoxic viral replication in tumor cells and induction of a systemic anti-tumor immune response.

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Suppression of glial tumor growth by expression of glial fibrillary acidic protein

Toda Masahiro, Miura Masayuki, Asou Hiroaki, Sugiyama Ichiro, Kawase Takeshi, Uyemura Keiichi

Neurochemical Research 24 ( 2 ) 339 - 343 1999

ISSN 0364-3190

We examined the effect of expression of glial fibrillary acidic protein (GFAP) on the tumor growth of astrocytoma in vivo. When rat astrocytoma C6 cells were injected subcutaneously in athymic mice, the cells produced tumors that grew rapidly. The tumor growth of C6 cells transfected with GFAP cDNA was significantly reduced compared to that of control NeoC6 cells transfected only with the neomycin resistant gene. After implantation of C6 cells transfected with mutated GFAP cDNA at the phosphorylation sites, the tumor growth was suppressed similar to that of the wild GFAP transfectants. To determine whether the cell growth suppression by GFAP is specific for astroglial cells, we assessed the effect of GFAP on the cell growth of an L cell of fibroblast origin in vitro. By GFAP cDNA transfection, L cells showed morphological changes, but the cell growth was not reduced. These results suggest that GFAP is a critical regulator of the tumor growth of astrocytoma.

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Attenuated, replication-competent herpes simplex virus type 1 mutant G207

Hunter William D., Martuza Robert L., Feigenbaum Frank, Todo Tomoki, Mineta Toshihiro, Yazaki Takahito, Toda Masahiro, Newsome Joseph T., Platenberg R. Craig, Manz Herbert J., Rabkin Samuel D.

Journal of Virology 73 ( 8 ) 6319 - 6326 1999

ISSN 0022-538X

This study examined the safety of intracerebral inoculation of G207, an attenuated, replication-competent herpes simplex virus type 1 (HSV-1) recombinant, in nonhuman primates. Sixteen New World owl monkeys (Aotus nancyme [karyotype 1, formerly believed to be A. trivirgatus]), known for their exquisite susceptibility to HSV-1 infection, were evaluated. Thirteen underwent intracerebral inoculation with G207 at doses of 10⁷ or 10⁹ PFU, two were vehicle inoculated, and one served as an infected wild-type control and received 10³ PFU of HSV-1 strain F. HSV-1 strain F caused rapid mortality and symptoms consistent with HSV encephalitis, including fever, hemiparesis, meningitis, and hemorrhage in the basal ganglia. One year after G207 inoculation, seven of the animals were alive and exhibited no evidence of clinical complications. Three deaths resulted from nonneurologic causes unrelated to HSV infection, and three animals were sacrificed for histopathologic examination. Two animals were reinoculated with G207 (10⁷ PFU) at the same stereotactic coordinates 1 year after the initial G207 inoculation. These animals were alive and healthy 2 years after the second inoculation. Cerebral magnetic resonance imaging studies performed both before and after G207 inoculation failed to reveal radiographic evidence of HSV-related sequelae. Despite the lack of outwardly observable HSV pathology, measurable increases in serum anti-HSV titers were detected. Histopathological examination of multiple organ tissues found no evidence of HSV-induced histopathology or dissemination. We conclude that intracerebral inoculation of up to 10⁹ PFU of G207, well above the efficacious dose in mouse tumor studies, is safe and therefore appropriate for human clinical trials.

Treatment of human breast cancer in a brain metastatic model by G207, a replication-competent multimutated herpes simplex virus 1

Toda Masahiro, Rabkin Samuel D., Martuza Robert L.

Human Gene Therapy 9 ( 15 ) 2177 - 2185 1998.10

ISSN 1043-0342

We investigated the therapeutic efficacy of G207, a replication-competent multimutated herpes simplex virus type 1, for the treatment of human malignant mammary tumors metastatic to the brain. In vitro studies demonstrated that G207 efficiently destroyed three of four human malignant breast cancer cell lines. MDA-MB-435 was most susceptible and MDA-MB-231 was least susceptible to G207. In athymic mice harboring subcutaneous or intracerebral MDA-MB-435 cells, intraneoplastic inoculation of G207 caused growth inhibition and/or prolonged survival. In contrast, G207 had minimal effects on MDA-MB-231 subcutaneous tumor growth or survival in the intracerebral tumor model. The efficacy of G207 therapy in vivo correlated well with the susceptibility of the human cancer cells to G207 in vitro. Histological studies indicate that G207 replication is restricted to tumor cells in vivo and does not occur in the surrounding brain tissue. These results suggest that G207 shows particular promise for use as a novel antineoplastic agent for metastatic brain tumors and that in vitro testing may predict which tumors will be most responsive in vivo.

In situ cancer vaccination

Toda Masahiro, Martuza Robert L., Kojima Hidefumi, Rabkin Samuel D.

Journal of Immunology 160 ( 9 ) 4457 - 4464 1998.05

ISSN 0022-1767

Intratumoral inoculation of replication-competent, attenuated herpes simplex virus (HSV) mutants inhibits tumor growth by direct cytotoxic viral replication and induction of a tumor-specific immune response. To boost the antitumor response, we describe a defective HSV vector encoding IL-12 as an adjuvant to in situ vaccination by the replicaton-competent HSV helper virus. The defective HSV vector system consists of defective particles containing tandem repeats of the cytokine genes (p40 and p35) in combination with a HSV helper virus. Heterodimeric IL-12 was expressed and secreted after IL-12 defective vector infection of tumor cells. In a syngeneic, bilateral established tumor model with CT26 murine colon carcinoma, unilateral intratumoral inoculation with an IL-12 defective/replication-competent HSV vector combination significantly reduced tumor growth of the inoculated and noninoculated contralateral tumors. This antitumor effect was significantly greater than with a lacZ-defective/replication-competent HSV vector combination, which itself was significantly greater than the mock inoculation. Efficacy is associated with enhancement of tumor-specific CTL activity, including specificity against the CT26 immunodominant MHC class I restricted Ag AH1, and IFN-γ production. There was no significant tumor growth inhibition after lntratumoral inoculation of s.c. CT26 tumors in athymic mice. We conclude that this defective HSV vector system is an effective method for cytokine gene delivery to tumors in situ and IL-12 expression in tumors synergizes the antitumor activity mediated by the replication-competent HSV helper virus.

Effect of a neuron-specific actin-binding protein, drebrin A, on cell-substratum adhesion

Ikeda Keiro, Shirao Tomoaki, Toda Masahiro, Asada Hideo, Toya Shigeo, Uyemura Keiichi

Neuroscience Letters 194 ( 3 ) 197 - 200 1995.07

ISSN 0304-3940

Drebrin A expression was induced in non-neuronal L cells via transfection with a vector containing the cDNA of rat drebrin A. Following treatment with colcemid (5 μg/ml) and cytochalasin D (0.5 μg/ml), most L cells collapsed into round cells, while drebrin expressing cells were resistant to the treatment, keeping their cell shapes. Simultaneously, actin filaments and microtubules were disrupted in both cell lines. By quantitative analysis, in the presence of cytochalasin D, the extent of cell spreading and cell attachment in drebrin expressing cells was significantly higher than that in control cells. These results suggest that drebrin A modulates cell-substratum adhesion. © 1995.

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Development of oligodendrocyte and myelination in the central nervous system.

Asou H., Murakami K., Toda M., Uyemura K.

Keio Journal of Medicine 44 ( 2 ) 47 - 52 1995.06

ISSN 0022-9717

We demonstrated the cell lineage of oligodendrocytes from the glial precursor cells to mature oligodendrocytes forming myelin sheath around the axon. There are several different stages of oligodendrocyte development in vito. So far there are no precise data about their morphological changes during oligodendrocyte development, but by the analysis using SEM and immunostaining, the characteristic morphological changes with serial expression of cell markers were observed in each developmental steps of oligodendrocyte. We have also clearly demonstrated how oligodendrocytes wrap around the axon by using video time-lapse movies. These results will be useful for understanding the exact cellular mechanism of myelination in the CNS.

Cell growth suppression of astrocytoma C6 cells by glial fibrillary acidic protein cDNA transfection

Toda Masahiro, Miura Masayuki, Asou Hiroaki, Toya Shigeo, Uyemura Keiichi

Journal of Neurochemistry 63 ( 5 ) 1975 - 1978 1994.11

ISSN 0022-3042

The cellular functions of the intermediate filament family including glial fibrillary acidic protein (GFAP) are not well known yet beyond their roles as structural elements of cells. Expression of GFAP, which is specific in astrocytes and regulated developmentally, suggests its involvement in cell growth and differentiation of astrocytes. We transfected murine GFAP cDNA into a rat astrocytoma C6 cell line to assess the specific effect of GFAP on cells. Two stable GFAP-transfected cell lines, GFC6-5 and GFC6-6, exhibited a series of morphological and growth characteristics that distinguish them from their counterparts, i.e., NeoC6 cells transfected only with the neomycin- resistant gene, and native C6 cells. Both GFC6-5 and GFC6-6 cells showed elongated cell shapes with extended processes rich in GFAP, markedly suppressed cell growth, and decreased bromodeoxyuridine uptake. Western blot analysis revealed a remarkable increase of GFAP expression in GFC6-5 and GFC6-6 compared with that in NeoC6 and C6, in contrast to similar vimentin expression in all cell lines. The results indicate that the expression of GFAP has dramatic effects on cell morphology and cell growth suppression in C6 cells, suggesting that GFAP may function as a tumor suppressor in astrocytoma.

GFAP transfected cells produce laminin, leading to neurite outgrowth promotion

Toda M., Asou H., Miura M., Toya S., Uyemura K.

NeuroReport 5 ( 15 ) 1969 - 1972 1994

ISSN 0959-4965

Accumulating evidence indicates the importance of astrocytes in neuronal development and regeneration. While glial fibrillary acidic protein (GFAP) is believed to mediate the morphology of developing astrocytes, its precise function remains unknown. To analyse the function of GFAP in astrocytes, we established GFAP-expressing cell lines by transfection of mouse GFAP cDNA into mouse fibroblast L cells. Stable transfectants expressed GFAP uniformly in the cytoplasm with no phenotypic changes and exhibited extended processes rich in GFAP. GFAP-expressing cells significantly promoted the neurite outgrowth of rat cerebral cortex neurones in the co-culture system. Analysis of the products of GFAP-expressing cells revealed an increase in production of laminin, but not fibronectin. These results suggest that L cells expressing GFAP increase laminin production, leading to promotion of neurite outgrowth.

Molecular-Cloning of cDNA Encoding Human Drebrin E and Chromosomal Mapping of Its Gene

Toda M., Shirao T., Minoshima S., Shimizu N., Toya S., Uyemura K.

Biochemical and Biophysical Research Communications 196 ( 1 ) 468 - 472 1993.10

ISSN 0006-291X

Drebrins are novel actin-binding proteins in the brain which are developmentally regulated. Three isoforms: two embryonic types (El and E2) and an adult type (A) are generated by alternative RNA splicing from a single drebrin gene in the chicken brain. A full length cDNA clone of human drebrin E has been isolated from a cDNA library of human fetus brain. The clone is 2596 base pairs in length and contains an open reading frame of 1947 nucleotides encoding a protein of 649 amino acids. The deduced amino acid sequence, except for the internal 138-nucleotide sequence (ins2), exhibits 88% homology with rat drebrin A. Spot blot hybridization using flow-sorted human chromosomes provides evidence that the gene encoding human drebrin protein locates on human chromosome 5. © 1993 Academic Press. All rights reserved.

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