Masamichi Hirayama

ORCID: 0000-0001-6281-3670
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About
Contact & Profiles
Research Areas
  • Drug Transport and Resistance Mechanisms
  • Gastrointestinal motility and disorders
  • Helicobacter pylori-related gastroenterology studies
  • Infant Health and Development
  • Metabolism and Genetic Disorders
  • Gastroesophageal reflux and treatments
  • Inflammatory mediators and NSAID effects
  • Material Properties and Applications
  • Biochemical Analysis and Sensing Techniques
  • Inflammatory Bowel Disease
  • S100 Proteins and Annexins
  • Drug-Induced Hepatotoxicity and Protection
  • Microscopic Colitis
  • Amino Acid Enzymes and Metabolism
  • Epilepsy research and treatment
  • Ion Transport and Channel Regulation
  • Trace Elements in Health
  • Eosinophilic Esophagitis
  • Diet and metabolism studies
  • Peroxisome Proliferator-Activated Receptors
  • Plant-based Medicinal Research
  • Neuropeptides and Animal Physiology
  • Estrogen and related hormone effects
  • Hemoglobinopathies and Related Disorders
  • Cancer Treatment and Pharmacology

Zeria Pharmaceutical (Japan)
2011-2020

Kanazawa University
2020

University of Florida
2018

Columbus Oncology and Hematology Associates
2018

Tokyo University of Science
2005-2006

Recently, it was reported that the organic cation/carnitine transporter 1 (OCTN1, <i>SLC22A4</i>) is associated with chronic inflammatory diseases, such as rheumatoid arthritis (RA) and Crohn9s disease. OCTN1 in humans expressed synovial tissues of individuals arthritis. Furthermore octn1 mice inflamed joints collagen-induced arthritis, a model human but not normal mice. should be involved disease present study, regulatory mechanism expression characterized using fibroblast-like synoviocyte...

10.1124/dmd.106.012112 article EN Drug Metabolism and Disposition 2006-12-01

Asacol, a medication that delivers delayed release 5-aminosalicylic acid (5-ASA), is useful therapeutic agent for inflammatory bowel disease (IBD), but the relationship between its pharmacological actions and intestinal concentrations has not been studied in detail. Therefore, our aim was to assess 5-ASA's as function of concentration at target site. We first evaluated profiles vitro by paddle method found Asacol starts 5-ASA pH ≥ 7. Orally administered pharmacokinetic parameters were dogs....

10.1021/mp200088z article EN Molecular Pharmaceutics 2011-05-10

Acotiamide, a gastroprokinetic agent used to treat functional dyspepsia, is transported at least two compartments in rat stomach. However, the role of these stomach pharmacokinetics and pharmacodynamics acotiamide remains unclear. Thus, purpose this study was elucidate relationship blood concentration with its inhibitory effect on acetylcholinesterase (AChE).Concentration profiles acetylcholine (ACh) were determined after intravenous administration rats analyzed by physiologically-based...

10.1007/s11095-015-1787-y article EN cc-by Pharmaceutical Research 2015-09-08

Abstract The pharmacokinetics (PK) and pharmacodynamics (PD) of proton pump inhibitors differ among cytochrome P450 (CYP) 2C19 genotypes. Therefore, we developed azeloprazole sodium (Z‐215), a novel inhibitor, whose metabolism is not affected by CYP2C19 activity in vitro. However, the PK PD have been evaluated Japanese subjects. We conducted an open‐label, crossover study healthy male volunteers to evaluate plasma concentration intragastric pH with respect genotype after repeated...

10.1002/jcph.1038 article EN The Journal of Clinical Pharmacology 2017-11-28

Acotiamide is a first-in-class prokinetic drug approved in Japan for the treatment of functional dyspepsia. Given that acotiamide enhances gastric motility conscious dogs and rats, we assessed vitro effects this on contraction guinea pig stomach strips acetylcholinesterase (AChE) activity homogenate following fundus removal. We also investigated serotonin 5-HT4 receptor agonist mosapride, dopamine D2 AChE inhibitor itopride, representative neostigmine. (0.3 1 μM) itopride (1 3 significantly...

10.1055/s-0035-1564084 article EN Drug Research 2015-09-29

Acotiamide is the first-in-class drug for treatment of functional dyspepsia. Although pharmacological and therapeutic actions acotiamide are thought to be derived from its inhibitory effects on acetylcholinesterase (AChE), whether concentration at site action sufficient inhibit AChE remains unclear. Since major cholinergic nerve terminals in gastric myenteric plexus, we studied distribution [(14)C]acotiamide into plexus.Distribution was evaluated using macro- micro-autoradiography rats...

10.1016/j.lfs.2015.12.020 article EN cc-by Life Sciences 2015-12-15

The human mass balance of [14 C]Z-215, a novel proton pump inhibitor, was characterised in six healthy male volunteers following single oral administration C]Z-215 (20 mg, 3.7 MBq) to determine the elimination pathway Z-215 and distribution its metabolites plasma, urine, faeces (NCT02618629). rapidly absorbed, with Cmax 434 ng/mL at 0.38 h for 732 ng eq./mL 0.5 total radioactivity. Means 59.61% 31.36% administered radioactive dose were excreted urine faeces, respectively, within 168...

10.1080/00498254.2017.1390625 article EN Xenobiotica 2017-11-02

The acetylcholinesterase inhibitor, acotiamide, improves gastric motility and is clinically used to treat functional dyspepsia. present study aimed identify the transporters involved in distribution of acotiamide stomach tissue. Acotiamide uptake by cancer-derived model cell line, Hs746 T, was Na+- pH-independent. initial velocity saturable with increasing concentrations inhibited selective serotonin reuptake inhibitors, which are potent inhibitors plasma membrane monoamine transporter...

10.1021/acs.molpharmaceut.9b00894 article EN Molecular Pharmaceutics 2020-02-27
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