Ohtani, Hisakazu

写真a

Affiliation

School of Medicine, Department of Clinical Pharmacy (Shinanomachi)

Position

Professor

Related Websites

External Links

Message from the Faculty Member 【 Display / hide

  • 医療薬学や臨床薬物動態学の楽しさを知っていただければと思います。

Profile Summary 【 Display / hide

  • 物理薬剤学や生物薬剤学、生化学、薬理学といった基礎薬学から、ヒトにおける臨床試験、患者や医療従事者を対象とした調査、疫学的調査、 医薬品情報、ファーマコメトリクス、IT技術にいたるさまざまな薬学領域の研究手法を活用することにより、おもに市販後の医薬品に関して、臨床的な問題点を解明し、適正かつ有効に使用するための 情報をつくるための研究を行っています。 具体的には、以下のような領域の研究を展開しています。 (1) 薬物の代謝過程やそこでの薬物相互作用の解析とテーラーメード医療への応用 (2) 消化管吸収過程における薬物相互作用の定量的予測 (3) 副作用軽減を目指した投与設計のための in vivo薬物動態・動力学的研究 (4) IT技術やファーマコメトリクスの活用による薬物治療の最適化

Other Affiliation 【 Display / hide

  • Keio University Hospital, Department of Pharmacy, Director

  • Faculty of Pharmacy, Department of Clinical Pharmacy, Concurrently appointed professor

Career 【 Display / hide

  • 1994.04
    -
    1999.01

    Research Associate, Pharmacist, The University of Tokyo Hospital

  • 1999.01
    -
    1999.10

    Ohtani Estate Co., Ltd.

  • 1999.11
    -
    2005.03

    Kyushu University, Graduate School of Pharmaceutical Sciences, Associate Professor

  • 2005.04
    -
    2009.03

    Associate Professor, Graduate School of Pharmaceutical Sciences, The University of Tokyo

  • 2008.04
    -
    2009.03

    Adjunct Associate Professor, Graduate School of Interdisciplinary Information Studies The University of Tokyo

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Academic Background 【 Display / hide

  • 1986.04
    -
    1990.03

    The University of Tokyo, Faculty of Pharmaceutical Science, 薬学科

    University, Graduated

  • 1990.04
    -
    1992.03

    The University of Tokyo, Graduate School of Pharmaceutical Sciences

    Graduate School, Completed, Master's course

Academic Degrees 【 Display / hide

  • 博士 (薬学) Ph.D. (Pharmacy), The University of Tokyo, Dissertation, 1999.05

Licenses and Qualifications 【 Display / hide

  • Pharmacist, 1990.05

  • JSPHCS-Certified Pharmacist, 2003.01

  • JSCPT-Certified Pharmacist, 2021.12

  • Certified National Tour Guide-Interpreter (English), 2016.02

  • 第一種放射線取扱主任者, (2010/10/28 試験合格), 2018.06

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Research Areas 【 Display / hide

  • Life Science / Clinical pharmacy (Clinical Pharmaceutical Science)

  • Life Science / Pharmacology (Applied Pharmacology)

Research Keywords 【 Display / hide

  • pharmacometrics

  • personalized medication

  • interindividual variation of pharmacokinetics

  • drug interactions

 

Books 【 Display / hide

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Papers 【 Display / hide

  • The effect of organic solvents on the in vitro transport activity of three OATP isoforms

    Saito R., Akiyoshi T., Tsujii K., Takahashi R., Kataoka H., Imaoka A., Ohtani H.

    Toxicology in Vitro 107   106059 2025.08

    ISSN  08872333

     View Summary

    Purpose: In vitro studies of transporter activity often require the addition of organic solvents such as dimethyl sulfoxide (DMSO), methanol, and ethanol, to dissolve substrates and/or inhibitors. Although this may attenuate the transport activity, the influence of different types of organic solvents on transporter activity has not been elucidated. This study aimed to quantitatively assess the impact of organic solvents on the transport activity of organic anion transporting polypeptide (OATP) 1B1, 1A2, and 2B1. Methods: The concentration-dependent influence of DMSO, methanol, and ethanol on the uptake of [<sup>3</sup>H]estrone 3-sulfate mediated by OATP1A2, OATP2B1 or 2′,7′-dichlorofluorescein (DCF) mediated by OATP1B1 was assessed using HEK293 cells expressed the respective OATP protein and the concentration that reduced the uptake by 20 % (IC<inf>20</inf>) was calculated. Results and discussion: The uptake activities of OATPs were reduced by methanol and ethanol in a concentration-dependent manner, with IC<inf>20</inf> values of 2.4–3.4 % and 0.51–3.8 % respectively. In contrast, DMSO did not affect the OATP2B1-mediated uptake at the maximum concentration (10 %) of DMSO whereas it exhibited concentration-dependent inhibition for OATP1B1 and 1A2 with IC<inf>20</inf> values of approximately 3 % and 0.7 %, respectively. This study provides useful information regarding experimental conditions for evaluating OATPs activity in vitro.

  • Comparative analysis of the single-molecule transport kinetics of OATP1B1 genetic variants

    Tsujii K., Yajima K., Akiyoshi T., Sakamoto K., Suzuki Y., Oka T., Imaoka A., Yamamura H., Kurokawa J., Ohtani H.

    Journal of Pharmacological Sciences 158 ( 3 ) 166 - 171 2025.07

    ISSN  13478613

     View Summary

    Several genetic variants of OATP1B1, a hepatic uptake transporter, increase the blood concentrations of substrate drugs, e.g., ∗15 carriers exhibit higher blood substrate concentrations than ∗1b carriers. It remains unclear whether these differences are due to changes in expression or intrinsic activity (transport activity per OATP1B1 molecule). This study compared the intrinsic activity of four OATP1B1 variants, ∗1a, ∗1b, ∗5, and ∗15, using HEK293 cell lines that co-expressed large-conductance Ca<sup>2+</sup>-activated K<sup>+</sup> (BK) channels and one of the OATP1B1 variants. To estimate the kinetic parameters K<inf>m</inf> and V<inf>max</inf>, 2′, 7′-dichlorofluorescein uptake was evaluated. The number of OATP molecules per cell (Q<inf>T</inf>) was calculated from BK channel-mediated whole-cell conductance and the OATP1B1/BK channel expression ratio (ρ) (determined by LC-MS/MS). V<inf>max,int</inf> (maximum intrinsic transport velocity) was obtained by dividing V<inf>max</inf> by Q<inf>T</inf>, and intrinsic clearance (CL<inf>int</inf>) was calculated as V<inf>max,int</inf>/K<inf>m</inf>. The K<inf>m</inf> values of ∗1a, ∗1b, ∗5, and ∗15 were 12.5, 9.19, 7.53, and 10.4 μM, and their V<inf>max,int</inf> values were 3.0, 7.0, 1.5, and 1.2 × 10<sup>−21</sup> mol/OATP molecule/min, respectively. Accordingly, the CL<inf>int</inf> value for OATP1B1∗15 was 15 % lower than that for OATP1B1∗1b, suggesting that the increased blood substrate concentrations observed in OATP1B1∗15 carriers may be due to the decreased intrinsic activity of OATP1B1∗15.

  • Efficacy of De-Escalation to Cefmetazole in Patients with Bacteremic Urinary Tract Infections Caused by Extended-Spectrum <i>β</i>-Lactamase-Producing <i>Escherichia coli</i>

    Namiki Takaya, Yokoyama Yuta, Kimura Motonori, Fukuda Shogo, Seyama Shoji, Iketani Osamu, Uwamino Yoshifumi, Jibiki Aya, Kawazoe Hitoshi, Ohtani Hisakazu, Hasegawa Naoki, Matsumoto Kazuaki, Oda Rentaro, Hashi Hideki, Suzuki Sayo, Nakamura Tomonori

    Biological and Pharmaceutical Bulletin (The Pharmaceutical Society of Japan)  48 ( 5 ) 537 - 544 2025.05

    ISSN  09186158

     View Summary

    <p>This study aimed to clarify the optimal value for the unbound cefmetazole concentration to remain above the minimum inhibitory concentration (MIC) (<i>f</i>T ≥ MIC) for efficacy of de-escalation to cefmetazole in patients with bacteremic urinary tract infection by extended-spectrum <i>β</i>-lactamase-producing <i>Escherichia coli</i>. This double-center retrospective observational study was conducted at Tokyo Bay Urayasu Ichikawa Medical Center and Keio University Hospital from January 2012 to October 2022. Efficacy was determined <i>via</i> clinical evaluation (mortality rate, recurrence rate, vital changes) and bacteriological evaluation, and the optimal <i>f</i>T ≥ MIC was calculated <i>via</i> receiver operating characteristic curve analysis. As a result, the number of patients evaluated were 40 (35 and 5 in the treatment success and treatment failure groups, respectively). Univariate analysis showed that <i>f</i>T ≥ MIC, recurrence rate, and MIC for cefmetazole against bacteria were significantly different for the two groups (<i>p</i> < 0.05). Receiver operating characteristic curve analysis showed that the optimal <i>f</i>T ≥ MIC indicating efficacy was 57% (area under the curve: 0.94, 95% confidence interval: 0.86–1.00, <i>p</i> = 0.002). All patients with <i>f</i>T ≥ MIC ≥ 57% had successful treatment, whereas the frequency of treatment failure was high among those with <i>f</i>T ≥ MIC <57%. The optimal <i>f</i>T ≥ MIC for the clinical efficacy of de-escalation to cefmetazole in patients with bacteremic urinary tract infection by extended-spectrum <i>β</i>-lactamase-producing <i>E. coli</i> was <i>f</i>T ≥ MIC ≥ 57%. This finding would be useful for optimal dosing of cefmetazole.</p>

  • Current Use of Generative Artificial Intelligence in Pharmacy Practice: A Literature Mini-review

    Kiyomiya Keisuke, Aomori Tohru, Kawazoe Hitoshi, Ohtani Hisakazu

    Iryo Yakugaku (Japanese Journal of Pharmaceutical Health Care and Sciences) (Japanese Society of Pharmaceutical Health Care and Sciences)  51 ( 4 ) 177 - 186 2025.04

    ISSN  1346342X

     View Summary

    <p>Generative artificial intelligence (AI), such as ChatGPT, is rapidly becoming popular and is expected to be utilized in pharmacy practice; however, the current utilization status and usefulness of generative AI are not well understood. Therefore, we aimed to review its current utilization status and assess its potential for use in pharmacy practice.</p><p>The literature review revealed that most studies evaluated the accuracy and completeness of responses from generative AI. ChatGPT-3.5 was reported to be less valuable owing to many errors but could be used in text summarization. ChatGPT-4 was reported to be superior to ChatGPT-3.5; however, its performance was still considered insufficient. The comparisons among the generative AIs were not sufficiently investigated. In conclusion, generative AI can potentially help clinical pharmacists in the future; however, its features and performance should be carefully monitored and evaluated using the latest version of generative AI when applied to pharmacy practice.</p>

  • Kinetics of the inhibition of CYP3A4 and CYP2C19 activity by jabara juice and identification of the responsible inhibitory components

    Koinuma K., Noto K., Morita T., Uekusa Y., Kikuchi H., Shimoji M., Seki H., Yamazaki H., Guengerich F.P., Nakamura K., Yamamoto K., Imaoka A., Akiyoshi T., Ohtani H.

    Journal of Pharmaceutical Sciences 114 ( 2 ) 849 - 856 2025.02

    ISSN  00223549

     View Summary

    Some citrus fruits are known to cause clinically significant drug interactions by inhibiting intestinal cytochrome P450 (CYP) enzymes. This in vitro study aimed to investigate the kinetics of the inhibition of CYP3A4 and CYP2C19 by the juice of jabara, a Japanese citrus fruit that does not contain furanocoumarins such as 6′,7′-dihydroxybergamottin, and to identify the inhibitory compound(s). CYP3A4 and CYP2C19 activity levels were determined in vitro using recombinant CYP preparations and their respective substrates. The ethyl acetate extract (EAE) of jabara juice was separated to isolate and identify the compound(s) that inhibited CYP3A4. Then, the time-dependent kinetics of the inhibition of CYP3A4 and CYP2C19 by the EAE and its inhibitory compound(s) were analyzed. The EAE of jabara juice was found to inhibit CYP3A4 in a time-dependent manner. Two flavonoids, 3,3′,4′,5,6,7,8-heptamethoxyflavone (HpMF) and 3,3′,4′,5,6,7-hexamethoxyflavone (HxMF), were identified as the responsible compounds. HpMF and HxMF inhibited CYP3A4 activity in a concentration- and time-dependent manner, with inhibition constants (K<inf>I</inf>) of 10.0 and 7.90 µM and maximal inactivation rate constants (k<inf>inact,max</inf>) of 0.00856 and 0.0134 min<sup>−1</sup>, respectively. The EAE did not inhibit CYP2C19, even when preincubation was employed. These findings imply that jabara juice may cause food-drug interactions via time-dependent inhibition of intestinal CYP3A4.

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Papers, etc., Registered in KOARA 【 Display / hide

Reviews, Commentaries, etc. 【 Display / hide

  • 基質特異性拡張型β-ラクタマーゼ産生腸内細菌目細菌菌血症性尿路感染症に対するセフメタゾールの最適なfT≧MICの同定

    並木 孝哉, 横山 雄太, 木村 元範, 福田 正悟, 瀬山 翔史, 池谷 修, 上蓑 義典, 長谷川 直樹, 松元 一明, 枦 秀樹, 中村 智徳, 地引 綾, 河添 仁, 大谷 壽一, 織田 錬太郎, 鈴木 小夜

    日本化学療法学会雑誌 ((公社)日本化学療法学会)  73 ( 1 ) 74 - 74 2025.01

    ISSN  1340-7007

  • ダラツムマブ皮下注時のInfusion-Related Reactionに対する抗ヒスタミン薬の有効性・安全性に関する多施設共同観察研究

    鈴川 真由, 鈴木 訓史, 葉山 達也, 藤田 行代志, 谷川 大夢, 小澤 有輝, 末廣 直哉, 鷲巣 晋作, 雨笠 愛実, 新井 隆広, 鈴木 洋平, 井澤 美苗, 望月 眞弓, 清宮 啓介, 石川 春樹, 青森 達, 大谷 壽一

    日本臨床腫瘍薬学会雑誌 ((一社)日本臨床腫瘍薬学会)  36   214 - 214 2024.05

  • PBPMに基づく薬剤師面談は外来患者の薬物治療の適正化とアドヒアランス向上をもたらす

    神成 はるか, 西松 直美, 小谷 宙, 櫻井 洋臣, 村松 博, 青森 達, 大谷 壽一

    日本エイズ学会誌 ((一社)日本エイズ学会)  25 ( 4 ) 431 - 431 2023.11

    ISSN  1344-9478

  • 骨髄腫の薬物治療の留意点 薬物動態と薬物相互作用の視点から(Pharmacokinetic aspects of drugs used for the treatment of myeloma)

    大谷 壽一

    International Journal of Myeloma ((一社)日本骨髄腫学会)  13 ( 3 ) 95 - 95 2023.05

  • 薬物相互作用の科学的評価とpersonalized medicationへの応用

    大谷 壽一

    TDM研究 ((一社)日本TDM学会)  39 ( 2 ) 38 - 38 2022.05

    ISSN  0911-1026

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Presentations 【 Display / hide

  • Drug-beverage interaction

    Hisakazu Ohtani

    29th Dubai International Pharmaceutical & Technologies Conference & Exhibition - DUPHAT (Dubai) , 

    2023.01

    Oral presentation (invited, special)

  • Pharmacy education in Japan - Clinical rotation and preceptorship -

    OHTANI Hisakazu

    Seminar National. Asosiasi Pendidikan Tinggi Farmasi Indonesia (APTFI) II (Banjarmasin, Indonesia) , 

    2017.11

    Oral presentation (invited, special), Association of Indonesian Pharmacy Higher Education (APTFI)

  • 医療連携で薬剤師に求められる臨床薬物動態学の基本

    OHTANI Hisakazu

    日本薬学会関東支部 薬剤師向け研修講演会 (前橋) , 

    2017.10

    Public lecture, seminar, tutorial, course, or other speech, 日本薬学会関東支部

    yakuzaishi2017.pdf

  • 受理される論文・されない論文

    OHTANI Hisakazu

    第1回 医療薬学教育セミナー (東京) , 

    2017.04

    Public lecture, seminar, tutorial, course, or other speech, 日本医療薬学会

  • フェノバルビタールと活性炭の相互作用は食事により減弱する

    IMAOKA Ayuko, OGATA Yuka, AKIYOSHI Takeshi, OHTANI Hisakazu

    日本薬学会第 137 年会 (仙台) , 

    2017.03

    Oral presentation (general)

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Research Projects of Competitive Funds, etc. 【 Display / hide

  • CYP2Cs及びOATPsを介した薬物ー飲食物間相互作用とその個人差の定量的解明

    2018.04
    -
    2021.03

    日本学術振興会, Grant-in-Aid for Scientific Research, Research grant, Principal investigator

  • Analysis of the inter-individual variations of food-drug interactions via CYP2Cs and OATPs

    2018.04
    -
    2021.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Ohtani Hisakazu, Grant-in-Aid for Scientific Research (C), Principal investigator

     View Summary

    The mechanism of food-drug interactions includes the inhibition of metabolic enzymes or drug transporters, which have genetic variations. The aim of this study is to clarify whether the genetic variations of metabolic enzymes and transporters lead to the altered inhibitory kinetics of respective inhibitors contained in a variety of fruit juices. We focused upon two metabolic enzymes (CYP2C9 and CYP2C19) and two transporters (OATP1A2 and OATP2B1). Detailed analysis revealed that the inhibitory kinetics of various inhibitors highly differ among genetic variants. Therefore, the genetic variants of metabolic enzymes and drug transporters are considered to be one of the important factors to confer inter-individual variation in the extent of food-drug interactions. We also succeeded in identifying a novel OATP inhibitor, narirutin, from grape fruit juice.

  • 薬物−飲食物間相互作用の強度に個人差をもたらす遺伝的要因の解明

    2015.04
    -
    2018.03

    日本学術振興会, Grant-in-Aid for Scientific Research, Principal investigator

  • Quantitative analysis of the factors that confer inter-individual variation of the extent of beverage-drug interactions

    2015.04
    -
    2018.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Hisakazu OHTANI, AKIYOSHI Takeshi, IMAOKA Ayuko, Grant-in-Aid for Scientific Research (C), Principal investigator

     View Summary

    The influences of genetic variation of CYP3A4 on the inhibitory kinetics of its inhibitors varied among the inhibitors and affected by the probe substrate used. The inhibitor manners (patterns) of metabolic inhibitors contained in fruit juice are different among CYP isoforms, i.e. CYP3A4, 2C9 and 2C19. The research should be focused upon the mode of inhibition that is clinically most relevant.
    Using newly developed cell lines stably expressing a transporter OATP1A2 or OATP2B1, some unidentified inhibitory ingredient(s) for these transporters are considered to be contained in some fractions of grapefruit juice.

  • Quantitative analysis of genetic factors affecting the extent of drug interactions via mechanism based inhibition of cytochrome P450

    2012.04
    -
    2015.03

    Keio University, Grant-in-Aid for Scientific Research, Hisakazu Ohtani, YAMAMOTO Koujirou, AKIYOSHI Takeshi, YAMAZAKI Hiroshi, Grant-in-Aid for Scientific Research (C), Research grant, Principal investigator

     View Summary

    There seems to be considerable inter-individual variations in the extent of drug interactions, especially via the inhibition of oxidative metabolic enzymes, P450s. This study aimed to investigate quantitatively the influence of genetic variation of P450s, such as CYP3A4 and CYP2D6, on the extent of drug interaction in the in vitro studies using genetic variants. As a result of enzymatic study with probe substrates and mechanism-based inhibitors (MBI), we concluded that the inhibitory potencies of MBI differ among genetic variants. These results suggest that the genetic variation of metabolic enzymes affect the extent of drug interactions caused by their inhibitors, as well as the pharmacokinetics of their substrate drugs.

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Awards 【 Display / hide

  • 日本医療薬学会賞

    2023.11, 日本医療薬学会, 薬物相互作用の個人差に関する医療薬学的研究

    Type of Award: Award from Japanese society, conference, symposium, etc.

  • 日本医療薬学会奨励賞

    2007.09, 日本医療薬学会, 薬物動態・動力学の活用によるテーラーメイド処方設計支援システムの基盤技術の確立

  • 年会優秀発表賞

    "丹羽しおり, 秋好健志, 今岡鮎子, 大谷壽一.", 2014.03, 日本薬学会第134年会, In vitro データをもとにした、CYP2D6 variants における paroxetine の非線型体内動態の予測.

  • 最優秀ポスター賞

    "三井梨恵子, 秋好健志, 今岡鮎子, 大谷壽一.", 2013.08, 医薬品情報学会 (第16回日本医薬品情報学会総会・学術大会), 免疫抑制剤、βblocker、ステロイドの低用量域における全身性副作用の用量依存性評価.

  • 優秀発表賞

    "○青野いづみ, 桑原亜記, 今井奈津美, 剱田侑希, 手塚淑人, 門田佳子, 小林典子, 鈴木小夜, 大谷壽一, 佐伯晴子, 木津純子.", 2013.03, 日本薬学会第133年会, 学生主体で構築した新たな服薬指導事前実習の評価.

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Courses Taught 【 Display / hide

  • STUDY OF MAJOR FIELD: (CLINICAL PHARMACY)

    2025

  • SEMINAR:(CLINICAL PHARMACY)

    2025

  • RESEARCH FOR BACHELOR'S THESIS 1

    2025

  • PRIOR LEARNING FOR CLINICAL PRACTICE 2

    2025

  • PHARMACOLOGY FOR NURSING AND HEALTH CARE

    2025

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Courses Previously Taught 【 Display / hide

  • 薬学への招待

    Keio University

    2015.04
    -
    2016.03

    Spring Semester, Lecture

  • C16(2)剤形をつくる

    Keio University

    2015.04
    -
    2016.03

    Autumn Semester, Lecture

  • C15(3)テーラーメイド薬物治療を目指して

    Keio University

    2015.04
    -
    2016.03

    Spring Semester, Lecture, Within own faculty

  • 臨床物理薬剤・製剤学

    Keio University

    2015.04
    -
    2016.03

    Spring Semester, Lecture

  • 老年薬学と在宅医療

    Keio University

    2015.04
    -
    2016.03

    Autumn Semester, Lecture

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Educational Activities and Special Notes 【 Display / hide

  • 第3回アジア薬科大学連合 Deans Forum "Regional Harmonization of Pharmacy Education in Asia" (組織委員・座長・ポスター発表)

    2014.06

    , Lecture at Education Method and Practice

 

Social Activities 【 Display / hide

  • JGSDF (Japanese Army) Reserve

    2011.11
    -
    Present

     View Summary

    Reserve Lieutenant Colonel (Pharmacy Officer)

Media Coverage 【 Display / hide

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Memberships in Academic Societies 【 Display / hide

  • The Pharmaceutical Society of Japan, 

    1990
    -
    Present
  • 日本医療薬学会, 

    1997
    -
    Present
  • Japanese Society of Drug Informatics (JASDI)

     
  • 日本薬理学会

     

Committee Experiences 【 Display / hide

  • 2023.10
    -
    2029.09

    Associate Member, Science Council of Japan

  • 2019.02
    -
    Present

    臨時委員, 薬事・食品衛生審議会

     View Remarks

    医薬品第一部会

  • 2009.05
    -
    Present

    Expert Committee Member, Pharmaceuticals and Medical Devices Agency

  • 2010.04
    -
    Present

    学術評議員, 日本薬理学会

  • 2009.04
    -
    Present

    Examination Committee Member, MR Education & Accreditation Center of Japan

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