Hitoshi Tada

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BACKGROUND A body-weight-based dose of tacrolimus often results in marked individual diversity of blood drug concentration. Tacrolimus is a substrate for cytochrome P450 (CYP) 3A5 and p-glycoprotein encoded by CYP3A5 and MDR1 (ABCB1), respectively, having multiple single nucleotide polymorphisms. In this study, we genotyped CYP3A5 A6986G, MDR1 G2677(A/T),(More)
Here, we describe the development of a rapid, simple and sensitive high-performance liquid chromatography (HPLC) method for the simultaneous quantitative determination of rabeprazole enantiomers (1a,b) and their metabolites, rabeprazole-thioether (2) and rabeprazole sulfone (3), in human plasma. Analytes and the internal standard (omeprazole-thioether) were(More)
The purpose of this study was to elucidate the pharmacokinetics of each enantiomer of lansoprazole and 5-hydroxylansoprazole in three different CYP2C19 genotype groups of Japanese subjects. Healthy subjects (n=18), of whom 6 were homozygous extensive metabolizers (homEMs), 6 were heterozygous extensive metabolizers (hetEMs) and 6 were poor metabolizers(More)
The objective of this study was to evaluate whether genetic polymorphisms of CYP2C19, CYP3A5 and MDR1 significantly impact the interaction between tacrolimus and rabeprazole or lansoprazole. Seventy-three recipients were randomly assigned after renal transplantation to receive repeated doses of tacrolimus for 28 days with a regimen of either 20 mg of(More)
We developed a rapid, simple, and sensitive high-performance liquid chromatography method with UV detection for the quantitative determination of mycophenolic acid (MPA) in human plasma. MPA and the internal standard (naproxen) were separated using a mobile phase of 0.04 M H(3)PO(4)-acetonitrile-methanol (3:3:4 v/v/v) over a CAPCELL PAK C18 MG column. A(More)
BACKGROUND AND OBJECTIVE Lansoprazole is extensively metabolised by cytochrome P450 (CYP) 2C19 and CYP3A4. The purpose of this study was to evaluate the effects of CYP3A5 polymorphism (A6986G) on the pharmacokinetics of lansoprazole enantiomers in renal transplant recipients who are CYP2C19 extensive metabolisers (EMs). METHODS Among 40 Japanese CYP2C19(More)
To investigate the molecular structural and functional characteristics of tumor-suppressive anti-ErbB-2 monoclonal antibody (mAb) SER4, we performed mAb-gene cloning and epitope mapping by a phage display system. Structural analysis demonstrated that both the heavy chain (HC) and light chain variable regions are highly homologous with the derived germline(More)
UGT1A8 and UGT2B7 are important uridine diphosphate-glucuronosyltransferase isoforms for the glucuronidation of mycophenolic acid (MPA). The aim of this investigation was to elucidate MPA pharmacokinetics in UGT1A8 and UGT2B7 genotypes in Japanese renal transplant recipients. Seventy-two recipients received repeated doses of mycophenolate mofetil and(More)
AIMS We investigated whether tacrolimus pharmacokinetics shows circadian variation and the influence of the CYP3A5 A6986G polymorphism on the pharmacokinetics in both the early and maintenance stages after renal transplantation. METHODS Tacrolimus was administered twice daily at specified times (09.00 and 21.00 h) throughout the pre- and post-transplant(More)
Rabeprazole is metabolized mainly non-enzymatically to rabeprazole-thioether. This in vitro study was designed to clarify the stereoselective oxidation mechanism and to identify the enzyme(s) involved in the metabolic breakdown of rabeprazole-thioether to rabeprazole. Rabeprazole-thioether was incubated with human liver microsomes and several recombinant(More)