Functional characterization of human xanthine oxidase allelic variants.

Objective: Xanthine oxidase (XO) catalyzes the oxidation of endogenous and exogenous purines and pyrimidines. In this study, we speculated that individual variations in XO activity are caused by genetic variations in the XO gene.

Methods: To investigate the genetic variations in XO in 96 Japanese participants, denaturing high-performance liquid chromatography was used.

Characterization of human cytochrome p450 enzymes involved in the metabolism of cilostazol.

Cilostazol (OPC-13013; 6-[4-(1-cyclohexl-1H-tetrazol-5-yl)butoxy]-3,4-dihydro-2(1H)-quinolinone) is widely used as an antiplatelet vasodilator agent. In vitro, the hydroxylation of the quinone moiety of cilostazol to OPC-13326 [6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydro-4-hydroxy-2(1H)-quinolinone], is the predominant route, and the hydroxylation of the hexane moiety to OPC-13217 is the second most predominant route. This study was carried out to identify and kinetically characterize the human cytochrome P450 (P450) isozymes responsible for the formation of the two major metabolites of cilostazol, namely, OPC-13326 and OPC-13217 [3,4-dihydro-6-[4-[1-(cis-4-hydroxycyclohexyl)-1H-tetrazol-5-yl)butoxy]-2(1H)-quinolinone)].

Three novel single nucleotide polymorphisms of the human thiopurine S-methyltransferase gene in Japanese individuals.

In this study, the entire coding sequence and the exon-intron junctions of the thiopurine S-methyltransferase (TPMT) gene from 200 Japanese individuals were screened for mutation. Three novel single nucleotide polymorphisms (SNPs) were identified-106G>A in exon 3 (Gly36Ser, *20 allele), 967A>G in 3'-untranslated region, and -87C>T in intron 8. The allele frequencies were 0.

Genetic polymorphisms and haplotype structures of the CYP4A22 gene in a Japanese population.

The CYP4A fatty acid monooxygenases oxidize endogenous arachidonic acid to 20-hydroxyeicosatetraenoic acid that acts as a regulator of blood pressure. Among the isoforms of the CYP4A subfamily, the human CYP4A22 was recently identified. In this study, we report the comprehensive investigation of polymorphisms in the CYP4A22 gene.

Competitive allele-specific short oligonucleotide hybridization (CASSOH) with enzyme-linked immunosorbent assay (ELISA) for the detection of pharmacogenetic single nucleotide polymorphisms (SNPs).

Individualization of drug therapy through genetic testing would maximize the effectiveness of medication and minimize its risks. Recent progress in genetic testing technologies has been remarkable, and they have been applied for the analysis of genetic polymorphisms that regulate drug responses. Clinical application of genetic information to individual health care requires simple and rapid identification of nucleotide changes in clinical settings.

Forensic assessment of 16 single nucleotide polymorphisms analyzed by hybridization probe assay.

Of a number of DNA marker typing techniques for personal identification in the field of forensic medicine, polymorphic short tandem repeat (STR) typing is currently the most frequently used technique. However, the multiplex STR method is time consuming. In contrast, single nucleotide polymorphism (SNP) detection methods are relatively rapid and amenable to high throughput.

A novel single nucleotide polymorphism of the human methylenetetrahydrofolate reductase gene in Japanese individuals.

The genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) have been associated with increased toxicity of methotrexate (MTX), a folic acid antagonist that is widely used to treat cancer and immunosuppressive disorders such as rheumatoid arthritis. In this study, we analyzed all the exons and exon/intron junctions of the MTHFR gene from 200 Japanese individuals. We detected a novel single nucleotide polymorphism (SNP) 148C>T (Arg46Trp) in exon 1.

Two novel single nucleotide polymorphisms (SNPs) of the CYP2D6 gene in Japanese individuals.

We analyzed all the exons and exon-intron junctions of the CYP2D6 gene from 286 Japanese individuals. We detected two novel single nucleotide polymorphisms (SNPs) 2556C>T in exon 5 (Thr261Ile) and 3835A>C in exon 8 (Lys404Gln). Both these SNPs showed a frequency of 0.

Genotyping of single nucleotide polymorphisms (SNPs) influencing drug response by competitive allele-specific short oligonucleotide hybridization (CASSOH) with immunochromatographic strip.

Using competitive allele-specific oligonucleotide hybridization with immunochromatographic strip (CASSOH), we have developed a simplified method for the detection of eight polymorphisms that are especially important in the identification of drug responders or non-responders and patients at increased risk of drug toxicity. The genotyping method is unambiguously determined by the presence or the absence of visible purple lines on the immunochromatographic strip, and results are obtained within 5 min after PCR. This method is rapid, highly sensitive, simplified, and should be suitable for point-of-care genotyping in clinical settings.

Three novel single nucleotide polymorphisms (SNPs) of the CYP2B6 gene in Japanese individuals.

We sequenced all exons and exon-intron junctions of the CYP2B6 gene from 200 Japanese individuals. We found three novel single nucleotide polymorphisms (SNPs) (1375A>G, 1427G>A and 1454A>T) causing amino acid substitutions (Met(459)Val, Gly(476)Asp and Gln(485)Leu in exon 9), respectively. The detected SNP was as follows: 1) SNP, 031226Hiratsuka01; GENE NAME, CYP2B6; ACCESSION NUMBER, AC023172; LENGTH, 25 base; 5'-CAGAACTTCTCCA/GTGGCCAGCCCCG-3'.

Human CYP4B1 gene in the japanese population analyzed by denaturing HPLC.

Human CYP4B1 is a CYP4 enzyme with activity towards xenobiotics. Five alleles of human CYP4B1 have been identified in French Caucasians, but allelic variants of enzyme have not been determined in the Japanese population. To establish a rapid and sensitive means of detecting variant CYP4B1 alleles, we analyzed those of 192 Japanese individuals using denaturing HPLC (DHPLC).