Naohito Shirai

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BACKGROUND Omeprazole is mainly metabolized in the liver by CYP2C19, a genetically determined enzyme, whereas rabeprazole is mainly reduced non-enzymatically and partially metabolized by CYP2C19. The therapeutic effects of rabeprazole are therefore assumed to be less affected by an individual's CYP2C19 status. AIM To investigate the acid inhibitory(More)
Proton pump inhibitors (PPIs), such as omeprazole, lansoprazole, rabeprazole, esomeprazole, and pantoprazole, are mainly metabolized by CYP2C19 in the liver. There are genetically determined differences in the activity of this enzyme. The genotypes of CYP2C19 are classified into the three groups, rapid extensive metabolizer (RM), intermediate metabolizer(More)
BACKGROUND AND PURPOSE A triple therapy with omeprazole, amoxicillin (INN, amoxicilline), and clarithromycin is widely used for the eradication of Helicobacter pylori. Omeprazole and clarithromycin are metabolized by CYP2C19 and CYP3A4. This study aimed to elucidate whether clarithromycin affects the metabolism of omeprazole. METHODS After administration(More)
BACKGROUND Anti-inflammatory cytokines play an important role in downregulation of inflammation and the prevention of neoplastic disorders. Genetic variations of anti-inflammatory cytokines are assumed to influence such responses. The aim of the present study was to clarify the association between the IL-10 polymorphism, one of the representative(More)
Helicobacter pylori eradication rates by triple therapy with a proton pump inhibitor, amoxicillin, and clarithromycin at standard doses depend on bacterial susceptibility to clarithromycin and patient CYP2C19 genotypes. We examined the usefulness of a personalized therapy for H. pylori infection based on these factors as determined by genetic testing.(More)
Proton pump inhibitors (PPIs), such as omeprazole, lansoprazole, rabeprazole, esomeprazole, and pantoprazole, are metabolized by cytochrome P450 isoenzyme 2C19 (CYP2C19) in the liver. There are genetic differences that affect the activity of this enzyme. The genotypes of CYP2C19 are classified into three groups: homozygous extensive metabolizer (homEM),(More)
BACKGROUND & AIMS Interleukin-1 beta (IL-1beta) polymorphisms are associated with increased risk of gastric cancer in whites. This study aimed to examine effects of these polymorphisms on gastric acid secretion, atrophic gastritis, and risk of peptic ulcer in Japan. METHODS We determined IL-1B-511/-31 and IL-1RN genotypes and measured gastric juice pH,(More)
BACKGROUND Proton pump inhibitors such as omeprazole and lansoprazole are mainly metabolized by CYP2C19 in the liver. The therapeutic effects of proton pump inhibitors are assumed to depend on CYP2C19 genotype status. OBJECTIVE We investigated whether CYP2C19 genotype status was related to eradication rates of H pylori by triple proton pump(More)
BACKGROUNDS AND AIMS The renin-angiotensin system plays an important role in homeostasis. Angiotensin II, which is generated by chymase and angiotensin I-converting enzyme (ACE), controls blood pressure as well as angiogenesis and cell proliferation. The aim of this study was to clarify the association of the chymase gene (CMA/B) and ACE polymorphisms with(More)
OBJECTIVE For the treatment of gastroesophageal reflux disease, intragastric pH should be lower than 4.0 for no more than 4 hours a day (<16.7%). We aimed to develop optimal dosage regimens for rabeprazole to control nocturnal acidity in relation to cytochrome P450 (CYP) 2C19 genotypes. METHODS Fifteen Helicobacter pylori -negative volunteers, comprising(More)