Issei Yamamoto

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Objectives: Chronopharmacokinetics of drugs metabolized by cytochrome P 450 3A (CYP3A) has been reported recently; however, little is studied on intra-individual circadian variation in CYP3A activity in human. The aim of this study was to assess the intra-individual diurnal variation and day-to-day variation of the urinary 6β-hydroxycortisol to cortisol(More)
Quantitative ultrasound (QUS) teehnology for the assessment of bone status has progressed rapidly over the last 10 years, and eome into wide use within a relatively short time period, sinee the deviees are less expensive and simpler than X-ray densitometrie machines, portable and involve no radiation exposure. In addition, it is antieipated that QUS may(More)
For consumer electronics and appliances, rectifier circuits of the capacitor input type are generally used. The various harmonics generated within such a power system become a serious problem. Various studies to reduce these effects have been presented so far. However, most of these employ switching devices, such as MOSFETs and the like. Removing the need(More)
The presence ofCampylobacter pylori was investigated in biopsy specimens obtained during gastrofiberscopy from 103 consecutive patients prospectively. Patients included 25 with gastric ulcer, 4 with duodenal ulcer, 5 with coexisting gastroduodenal ulcer, 31 with gastroduodenal ulcer with gastritis, 27 with gastritis, 3 with gastric polyps and 8 with gastric(More)
The effect of three new fluoroquinolones on theophylline kinetics and the urinary excretion of metabolites was studied in 5 healthy subjects (3 male, 2 female). All subjects received serial, single i.v. infusions of theophylline (aminophylline, 250 mg) over 60 min after 200 mg doses of a quinolone (enoxacin, ofloxacin, norfloxacin) every 8 h for 3(More)
Objective: The cytochrome P 450 isozymes CYP2D6 and CYP2C19 exhibit genetic polymorphism in human, including a marked interethnic difference. As the functional status of the isozymes CYP2D6 and CYP2C19 have an impact on the pharmacokinetics of some antidepressants, we investigated whether the disposition of venlafaxine was affected by the CYP2D6 and CYP2C19(More)
Objectives: Omeprazole is metabolized mainly by CYP2C19 which has two major mutations (CYP2C19*2 in exon5 and CYP2C19*3 in exon4) associated with the poor metabolizer (PM) phenotype. The aim of this study was to examine the relationship between genetic polymorphism of CYP2C19 and metabolism of omeprazole administrated as a single dose or as repeated-doses,(More)
We report a 40-year-old woman, who initially developed cerebellar symptoms, with multiple hemorrhagic brain metastases from a papillary thyroid cancer. Intracranial masses gave heterogeneous high signal on T 1-weighted and T 2-weighted images, hemosiderin rims on the latter. Some of the tumors showed contrast enhancement. Metastatic thyroid cancer is a(More)
Electrophoregrams of restriction endonuclease digests of the chromosomal DNA of Helicobacter pylori (H.p.) are extremely different frqm each other I) among u n ~ i---solates, though identical in terms of biotype . There is, however, still no sufficient criterion to propose genotype based on the genomic diversity. The aim of this study is to examine(More)