Koji Takeuchi

Kyoto Pharmaceutical University, Kioto, Kyōto, Japan

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Publications (415)1907.72 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We examined the prophylactic effect of rebamipide on gastric bleeding induced by the perfusion of aspirin (acetylsalicylic acid [ASA]) plus clopidogrel under the stimulation of acid secretion in rats. Under urethane anesthesia, acid secretion was stimulated by the i.v. infusion of histamine (8 mg/kg/h), and the stomach was perfused with 25 mmol/L ASA at a rate of 0.4 mL/min. Gastric bleeding was evaluated as the concentration of hemoglobin in the perfusate. Clopidogrel (30 mg/kg) was given p.o. 24 h before the perfusion. Rebamipide (3-30 mg/kg) or other antiulcer drugs were given i.d. before the ASA perfusion. Slight gastric bleeding or damage was observed with the perfusion of ASA under the stimulation of acid secretion, whereas these responses were significantly increased in the presence of clopidogrel. Both omeprazole and famotidine inhibited acid secretion and prevented these responses to ASA plus clopidogrel. Rebamipide had no effect on acid secretion, but dose-dependently prevented gastric bleeding in response to ASA plus clopidogrel, with the degree of inhibition being almost equivalent to that of the antisecretory drugs, and the same effects were obtained with the gastroprotective drugs, irsogladine and teprenone. These agents also reduced the severity of gastric lesions, although the effects were less than those of the antisecretory drugs. These results suggest that the antiplatelet drug, clopidogrel, increases gastric bleeding induced by ASA under the stimulation of acid secretion, and the gastroprotective drug, rebamipide, is effective in preventing the gastric bleeding induced under such conditions, similar to antisecretory drugs. © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.
    Journal of Gastroenterology and Hepatology 12/2014; 29 Suppl S4:37-46. DOI:10.1111/jgh.12774 · 3.63 Impact Factor
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    ABSTRACT: We investigated the roles of cyclooxygenase (COX) isozymes and prostaglandins (PGs) and their receptors in mucosal defense against cold-restraint stress (CRS)-induced gastric lesions. Male C57BL/6 wild-type (WT) mice and those lacking COX-1 or COX-2 as well as those lacking EP1, EP3, or IP receptors were used after 18 h fasting. Animals were restrained in Bollman cages and kept in a cold room at 10°C for 90 min. CRS induced multiple hemorrhagic lesions in WT mouse stomachs. The severity of these lesions was significantly worsened by pretreatment with the nonselective COX inhibitors (indomethacin, loxoprofen) or selective COX-1 inhibitor (SC-560), while neither of the selective COX-2 inhibitors (rofecoxib and celecoxib) had any effect. These lesions were also aggravated in animals lacking COX-1, but not COX-2. The expression of COX-2 mRNA was not detected in the stomach after CRS, while COX-1 expression was observed under normal and stressed conditions. The gastric ulcerogenic response to CRS was similar between EP1 or EP3 knockout mice and WT mice, but was markedly worsened in animals lacking IP receptors. Pretreating WT mice with iloprost (the PGI2 analog) significantly prevented CRS-induced gastric lesions in the presence of indomethacin. PGE2 also reduced the severity of these lesions, and the effect was mimicked by the EP4 agonist, AE1-329. These results suggest that endogenous PGs derived from COX-1 play a crucial role in gastric mucosal defense during CRS, and this action is mainly mediated by PGI2 /IP receptors and partly by PGE2 /EP4 receptors. © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.
    Journal of Gastroenterology and Hepatology 12/2014; 29 Suppl S4:3-10. DOI:10.1111/jgh.12767 · 3.63 Impact Factor
  • Koji Takeuchi
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    ABSTRACT: Prostaglandin E2 not only prevents NSAID-generated small intestinal lesions, but also promotes their healing. The protective effects of prostaglandin E2 are mediated by the activation of EP4 receptors and functionally associated with the stimulation of mucus/fluid secretions and inhibition of intestinal hypermotility, resulting in the suppression of enterobacterial invasion and iNOS up-regulation, which consequently prevents intestinal lesions. Prostaglandin E2 also promotes the healing of intestinal damage by stimulating angiogenesis through the up-regulation of VEGF expression via the activation of EP4 receptors. These findings have contributed to a further understanding of the mechanisms responsible for ‘protective’ and ‘healing-promoting’ effects of prostaglandin E2 and the development of new strategies for the prophylactic treatment of NSAID-induced enteropathy.
    Current Opinion in Pharmacology 12/2014; 19:38–45. DOI:10.1016/j.coph.2014.07.005 · 4.23 Impact Factor
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    ABSTRACT: Hydrogen sulfide (H2S) is known to be an important gaseous mediator that affects various functions under physiological and pathological conditions. We examined the effects of NaHS, a H2S donor, on HCO3(-) secretion in rat stomachs and investigated the mechanism involved in this response. Under urethane anesthesia, rat stomachs were mounted on an ex vivo chamber and perfused with saline. Acid secretion had been inhibited by omeprazole. The secretion of HCO3(-) was measured at pH 7.0 using a pH-stat method and by the addition of 10 mM HCl. NaHS (0.5-10 mM) was perfused in the stomach for 5 min. Indomethacin or L-NAME was administered s.c. before NaHS treatment, while glibenclamide (a KATP channel blocker), ONO-8711 (an EP1 antagonist), or propargylglycine (a cystathionine γ-lyase inhibitor) was given i.p. before. The mucosal perfusion of NaHS dose-dependently increased the secretion of HCO3(-), and this effect was significantly attenuated by indomethacin, L-NAME, and sensory deafferentation, but not by glibenclamide or ONO-8711. The luminal output of nitric oxide, but not the mucosal production of prostaglandin E2, was increased by the perfusion of NaHS. Mucosal acidification stimulated HCO3(-) secretion, and this response was inhibited by sensory deafferentation, indomethacin, L-NAME, and ONO-8711, but not by propargylglycine. These results suggested that H2S increased HCO3(-) secretion in the stomach, and this effect was mediated by capsaicin-sensitive afferent neurons and dependent on nitric oxide and prostaglandins, but not ATP-sensitive K(+) channels. Further study is needed to define the role of endogenous H2S in the mechanism underlying acid-induced gastric HCO3(-) secretion. Copyright © 2014 Elsevier Inc. All rights reserved.
    Nitric Oxide 11/2014; 46. DOI:10.1016/j.niox.2014.11.001 · 3.18 Impact Factor
  • Koji Takeuchi, Jian-Ying Wang
    Current Opinion in Pharmacology 10/2014; DOI:10.1016/j.coph.2014.09.014 · 4.23 Impact Factor
  • Koji Takeuchi, Eitaro Aihara
    Capsaicin - Sensitive Neural Afferentation and the Gastrointestinal Tract: from Bench to Bedside, Edited by Gyula Mozsik, Omar M. E. Abdel- Salam, Koji Takeuchi, 07/2014: chapter 6; InTech., ISBN: 978-953-51-1631-8
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    ABSTRACT: The present study compared the effects of frequently used anti-platelet drugs, such as clopidogrel, ticlopidine, and cilostazol, on the gastric bleeding and ulcerogenic responses induced by intraluminal perfusion with 25mM aspirin acidified with 25mM HCl (acidified ASA) in rats.
    Life Sciences 06/2014; DOI:10.1016/j.lfs.2014.06.017 · 2.30 Impact Factor
  • Gastroenterology 05/2014; 146(5):S-508. DOI:10.1016/S0016-5085(14)61838-2 · 13.93 Impact Factor
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    ABSTRACT: We examined the effect of H2S on duodenal HCO3- secretion in rats and investigated the mechanism involved in this response. Animals were fasted overnight and anesthetized with urethane. A duodenal loop was perfused with saline, and HCO3- secretion was measured at pH 7.0 using a pH stat-method. The loop was perfused at a rate of 0.2 mL/min with NaHS (H2S donor) for 5 min or 10 mM HCl for 10 min. Indomethacin or l-NAME was given s.c. 30 min or 3 h, respectively, before NaHS or acidification, while glibenclamide (KATP channel blocker) or propargylglycine (cystathionine-g-lyase inhibitor) was given i.p. 30 min before. Mucosal perfusion with NaHS dose-dependently increased the HCO3- secretion, and this effect was significantly attenuated by indomethacin and l-NAME as well as sensory deafferentation, but not by glibenclamide. Mucosal PGE2 and NO production were both increased by NaHS perfusion. Mucosal acidification stimulated HCO3- secretion concomitant with increase in PGE2 and NO production, and these responses were mitigated by propargylglycine. The duodenal damage induced by acid (100 mM HCl for 4 h) was aggravated by pretreatment with propargylglycine. These results suggest that H2S increases HCO3- secretion in the duodenum, and this action is partly mediated by PG and NO as well as by capsaicin-sensitive afferent neurons. It is assumed that endogenous H2S is involved in the regulatory mechanism of acid-induced HCO3- secretion and mucosal protection in the duodenum.
    Nitric Oxide; 05/2014
  • Koji Takeuchi, Kikuko Amagase, Hiroshi Satoh
    Gastroenterology 05/2014; 146(5):S-506. DOI:10.1016/S0016-5085(14)61830-8 · 13.93 Impact Factor
  • Gastroenterology 05/2014; 146(5):S-699. DOI:10.1016/S0016-5085(14)62540-3 · 13.93 Impact Factor
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    ABSTRACT: Lubiprostone, a bicyclic fatty acid derived from prostaglandin E1, has been used to treat chronic constipation and irritable bowel syndrome, and its mechanism of action has been attributed to the stimulation of intestinal fluid secretion via the activation of ClC-2/CFTR chloride channels. We examined the effects of lubiprostone on indomethacin-induced enteropathy and investigated the functional mechanisms involved, including its relationship with the EP4 receptor subtype. Male SD rats were administered indomethacin (10 mg/kg) p.o. and killed 24 h later to examine the hemorrhagic lesions that developed in the small intestine. Lubiprostone (0.01-1mg/kg) was administered p.o. in a single injection 30 min before the indomethacin treatment. Indomethacin markedly damaged the small intestine, accompanied by intestinal hypermotility, a decrease in mucus and fluid secretion, and an increase in enterobacterial invasion as well as the up-regulation of iNOS and TNFα mRNAs. Lubiprostone significantly reduced the severity of these lesions, with the concomitant suppression of the functional changes. The effects of lubiprostone on the intestinal lesions and functional alterations were significantly abrogated by the co-administration of AE3-208, a selective EP4 antagonist, but not by CFTR(inh)-172, a CFTR inhibitor. These results suggested that lubiprostone may prevent indomethacin-induced enteropathy via an EP4 receptor-dependent mechanism. This effect may be functionally associated with the inhibition of intestinal hypermotility and increase in mucus/fluid secretion, resulting in the suppression of bacterial invasion and iNOS/TNFα expression, which are major pathogenic events in enteropathy. The direct activation of CFTR/ClC-2 chloride channels is unlikely to have contributed to the protective effects of lubiprostone.
    Journal of Pharmacology and Experimental Therapeutics 04/2014; 349(3). DOI:10.1124/jpet.114.213991 · 3.86 Impact Factor
  • Source
    Koji Takeuchi, Kenji Nagahama
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    ABSTRACT: Esophagitis was induced in rats within 3 h by ligating both the pylorus and transitional region between the forestomach and glandular portion under ether anesthesia. This esophageal injury was prevented by the administration of acid suppressants and antipepsin drug and aggravated by exogenous pepsin. Damage was also aggravated by pretreatment with indomethacin and the selective COX-1 but not COX-2 inhibitor, whereas PGE2 showed a biphasic effect depending on the dose; a protection at low doses, and an aggravation at high doses, with both being mediated by EP1 receptors. Various amino acids also affected this esophagitis in different ways; L-alanine and L-glutamine had a deleterious effect, while L-arginine and glycine were highly protective, both due to yet unidentified mechanisms. It is assumed that acid/pepsin plays a major pathogenic role in this model of esophagitis; PGs derived from COX-1 are involved in mucosal defense of the esophagus; and some amino acids are protective against esophagitis. These findings also suggest a novel therapeutic approach in the treatment of esophagitis, in addition to acid suppressant therapy. The model introduced may be useful to test the protective effects of drugs on esophagitis and investigate the mucosal defense mechanism in the esophagus.
    02/2014; 2014:532594. DOI:10.1155/2014/532594
  • Chapter: Organoid
    G.I. Research, 01/2014: pages 100-102; SENTAN IGAKU-SHA.
  • Source
    Hiroshi Satoh, Kikuko Amagase, Koji Takeuchi
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    ABSTRACT: Antisecretory drugs such as histamine H2-receptor antagonists and proton pump inhibitors are commonly used for the treatment of upper gastrointestinal mucosal lesions induced by NSAIDs. However, it has recently been reported that these drugs exacerbate NSAID-induced small intestinal lesions in rats. Unfortunately, there are few effective agents for the treatment of this complication. We examined the effects of mucosal protective agents (MPAs), misoprostol, irsogladine and rebamipide, and mucin of porcine stomach on diclofenac-induced intestinal lesions and the exacerbation of the lesions by ranitidine or omeprazole. The effects of the drugs on intestinal motility and mucus distribution/content were also examined. Male Wistar rats (180-220 g) were used. Each drug was administered orally under fed conditions. Diclofenac (1-10 mg/kg) produced multiple lesions in the small intestine dose-dependently. Both ranitidine (30) and omeprazole (100) significantly increased the intestinal lesions induced by low doses (3 and 6) of diclofenac. All of misoprostol (0.03-0.3), irsogladine (3-30) and rebamipide (30-300) as well as mucin (30-300) inhibited the formation of intestinal lesions caused by a high dose (10) of diclofenac alone and prevented the exacerbation of diclofenac-induced lesions by antisecretory drugs. Diclofenac (10) markedly increased the intestinal motility and decreased the mucosal mucus, and the decrease of mucus was significantly inhibited by the MPAs. These results indicate the usefulness of the MPAs for the treatment of intestinal lesions induced by NSAIDs alone or by co-administration with antisecretory drugs, and suggest that mucus plays an important role in the protection of intestinal mucosa by the MPAs.
    Journal of Pharmacology and Experimental Therapeutics 11/2013; 59(8). DOI:10.1124/jpet.113.208991 · 3.86 Impact Factor
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    ABSTRACT: High-mobility group box 1 (HMGB1) was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR) 2, TLR4, and receptor for advanced glycation end products (RAGE), leading to tissue injury. Although HMGB1's ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1's effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO) activity, and the expression of tumor necrosis factor α (TNFα) mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO) mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses.
    PLoS ONE 11/2013; 8(11):e80130. DOI:10.1371/journal.pone.0080130 · 3.53 Impact Factor
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    ABSTRACT: We examined changes in the expression of a pro-angiogenic factor, vascular endothelial growth factor (VEGF), and an anti-angiogenic factor, endostatin, as well as matrix metalloproteinase (MMP)-2 and MMP-9 in the rat small intestine after administration of indomethacin and investigated the roles of these factors in the healing of indomethacin- induced small intestinal ulcers. Male SD rats were given indomethacin (10 mg/kg) p.o. and euthanized at various time points (3-24 h and 2-7 days) after the administration. To impair the healing of these lesions, low-dose of indomethacin (2 mg/kg) was given p.o. once daily for 6 days starting 1 day after ulceration. Levels of VEGF, endostatin, MMP-2 and MMP-9 were determined by Western blotting. The expression of both VEGF and endostatin was upregulated after the ulceration. Repeated administration of low-dose indomethacin impaired the ulcer healing with a decrease of VEGF expression and a further increase of endostatin expression, resulting in a marked decrease in the ratio of VEGF/endostatin expression. The levels of MMP-2 and MMP-9 were both significantly increased after the ulceration, but these responses were suppressed by the repeated indomethacin treatment. The healing of these ulcers was significantly delayed by the repeated administration of MMP inhibitors such as ARP-101 and SB-3CT. The results confirm the importance of the balance between pro-angiogenic and anti-angiogenic activities in the healing of indomethacin-induced small intestinal damage and further suggest that the increased expression of MMP-2 and MMP-9 is another important factor for ulcer healing in the small intestine.
    Life sciences 07/2013; DOI:10.1016/j.lfs.2013.07.021 · 2.30 Impact Factor
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    ABSTRACT: We reviewed the prophylactic effect of monosodium glutamate (MSG), a substance known as the "umami", on NSAID-induced small intestinal damage in rats. Loxoprofen, one of NSAIDs frequently used in Asian countries, given orally at 60 mg/kg, caused hemorrhagic damage in the small intestine, mainly jejunum and ileum, concomitant with a down-regulation of Muc2 expression/mucus secretion and an up-regulation of enterobacterial invasion and neutrophil migration as well as inducible nitric oxide synthase (iNOS) expression. The severity of these lesions was reduced by pretreatment with MSG (0.1~5%) given as a mixture of powder food (10 g/rat/day) for 5 days before administration of loxoprofen. The effect of MSG was accompanied by an up-regulation of Muc2 expression/mucus secretion as well as a suppression of bacterial invasion, iNOS expression and myeloperoxidase activity. On the other hand, these lesions spontaneously healed within 7 days, but this process was hampered by loxoprofen at low doses (>10 mg/kg) given repeatedly for 5 days after ulceration. The healing-impairment effect of loxoprofen was accompanied by the down-regulation of vascular endothelium-derived growth factor (VEGF) expression and angiogenic response, and these responses were all antagonized by feeding diet containing 5% MSG for 5 days after ulceration. It is suggested that MSG exhibits a prophylactic effect against loxoprofen-induced small intestinal lesions, this effect is functionally associated with the up-regulation of Muc2 expression/mucus secretion, resulting in suppression of enterobacterial invasion and iNOS expression, the major pathogenic events in NSAID-induced enteropathy, and MSG also has the healing promoting effect on these lesions through enhancement of VEGF expression and angiogenesis.
    Current pharmaceutical design 07/2013; DOI:10.2174/13816128113199990579 · 3.29 Impact Factor
  • Hiroshi Satoh, Kikuko Amagase, Koji Takeuchi
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    ABSTRACT: BACKGROUND/AIMS: The effects of feeding conditions (fasted or fed) and dietary fiber (DF) in the diet on gastrointestinal (GI) damage induced by aspirin (ASA) were examined in cats. METHODS: Plain ASA (P-ASA, 20 mg/kg) or one enteric-coated ASA tablet (EC-ASA, containing 100 mg ASA) was administered p.o. once daily for 3 or 7 days just after morning meal, 3 h after the evening meal, or in the morning without a morning meal (fasted). Several types of diet, dry food (DRY, DF: 2.8 %), canned food (CAN, DF: 0.4 %), and diets with added cellulose or pectin were provided twice daily. RESULTS: P-ASA or EC-ASA administered just after feeding of DRY caused marked lesions in the GI tract, although EC-ASA did not produce any lesions in the stomach. GI damage was markedly decreased when ASA was administered 3 h after the evening meal. The induction of lesions by EC-ASA was markedly decreased in cats that ate CAN, but lesions were induced in cats fed CAN with added cellulose (6 %). The addition of pectin (6 %) to the DRY markedly decreased the induction of lesions by EC-ASA. CONCLUSIONS: The results indicate that the induction of GI lesions by ASA was highly dependent on the feeding conditions and DF. To minimize the induction of GI damage, it would be better to take ASA 3 h after the evening meal, or after consuming diets that contain low amounts of insoluble DF and high amounts of soluble DF.
    Digestive Diseases and Sciences 06/2013; 58(10). DOI:10.1007/s10620-013-2725-7 · 2.55 Impact Factor
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    ABSTRACT: We set up two models of gastric bleeding in rats using low-dose aspirin (ASA) and the antiplatelet drug clopidogrel, a P2Y12 receptor antagonist, and examined the effect of antiulcer drugs on gastric bleeding and ulcerogenic responses under such conditions. Under urethane anesthesia, two catheters were inserted into the rat stomach, one from the esophagus and another through the pylorus via an incision in the duodenum. In the first model, the stomach was perfused with 25 mM ASA dissolved in 50 mM HCl using an infusion pump, and gastric bleeding was measured as the hemoglobin concentration in perfusate collected every 15 min. In the second model, the stomach was perfused with ASA under stimulation of acid secretion by a continuous i.v. infusion of histamine (8 mg/kg/hr). Clopidogrel (30 mg/kg) was given p.o. 24 h before the ASA perfusion, while antiulcer drugs were given i.d. or i.v. 80 min before. Perfusion of the stomach with acidified ASA or ASA under histamine-stimulated acid secretion caused minimal bleeding in the stomach with few lesions. The ulcerogenic and bleeding responses to ASA under these conditions were markedly aggravated by pretreatment with clopidogrel, which by itself provoked neither bleeding nor damage. Antiulcer drugs, such as prostaglandin E2, irsogladine, rebamipide and teprenone, reduced the severity of gastric bleeding and damage in response to ASA plus clopidogrel in the presence of both exogenous and endogenous acid. In contrast, antisecretory drugs such as a proton pump inhibitor and histamine H2 receptor antagonists markedly suppressed the gastric bleeding and lesion responses to ASA plus clopidogrel under histamine-stimulated acid secretion, but had not effect on the responses to acidified ASA plus clopidogrel. These results suggest that clopidogrel increases gastric bleeding induced by ASA and that antiulcer drugs are useful for preventing gastric bleeding caused by the dual antiplatelet therapy.
    Current pharmaceutical design 06/2013; DOI:10.2174/13816128113199990418 · 3.29 Impact Factor

Publication Stats

5k Citations
1,907.72 Total Impact Points


  • 1987–2014
    • Kyoto Pharmaceutical University
      • Laboratory of Pharmacology and Experimental Therapeutics
      Kioto, Kyōto, Japan
  • 2013
    • Doshisha Women's College of Liberal Arts
  • 2009
    • Kumamoto University
      • Graduate School of Pharmaceutical Sciences
      Kumamoto-shi, Kumamoto Prefecture, Japan
    • Osaka City University
      • Department of Gastroenterology
      Ōsaka, Ōsaka, Japan
  • 2007
    • Yamaguchi University
      Yamaguti, Yamaguchi, Japan
  • 2000
    • Kyoto University
      Kioto, Kyōto, Japan
  • 1998
    • University of Gdansk
      • Faculty of Chemistry
      Danzig, Pomeranian Voivodeship, Poland
  • 1977
    • Bunkyo University
      Edo, Tōkyō, Japan
  • 1975–1977
    • The University of Tokyo
      • Department of Pharmaceutical Sciences
      Tōkyō, Japan