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Biomedical subjects

T Nambara

Publications and source records attributed to T Nambara.

At least 145 records · Page 8Linked to original sources
PubMed1982

Determination of captopril in human blood by high-performance liquid chromatography with electrochemical detection.

A new method for quantitation of captopril in human blood is described. Captopril was derivatized with N-(4-dimethylaminophenyl)maleimide into the electrochemically active adduct. The derivative was separated and determined by high-performance liquid chromatography with an electrochemical detector on a reversed-phase column. The proposed method was satisfactory for determination of captopril in whole blood with respect to accuracy and precision. The detection limit of captopril thereby obtained was 10 ng/ml. The blood levels of captopril in patients orally given an official dose were measured by the present method.

Adult↗
PubMed1982

Preparation of specific antiserum to estradiol 3-glucuronide.

The preparation and antigenic properties of estradiol 3-glucuronide-bovine serum albumin (BSA) conjugate in which the hapten is coupled to the carrier protein through the aminomethyl group at C-6 by glutaraldehyde, have been described. Antibody raised against the immunogen in the rabbit possessed high affinity (Ka = 3.7 x 10(9) M-1) and excellent specificity to estradiol 3-glucuronide, exhibiting no significant cross-reactivities with estrogen glucuronides except for estriol 3-glucuronide (3.64%) and no cross-reactions with free estrogens, their sulfates and other steroids.

Animals↗
PubMed1982

Preparation and antigenic properties of estriol 16-glucuronide- and estradiol 17-glucuronide-[C-6]-bovine serum albumin conjugates.

The preparation and antigenic properties of estriol 16-glucuronide-bovine serum albumin (BSA) and estradiol 17-glucuronide-BSA conjugates in which the hapten molecule is linked to the carrier protein through an (O-carboxymethyl)oxime bridge at the C-6 position on the steroid nucleus, have been described. Antibodies raised against the two immunogens in the rabbit possessed excellent specificity to estriol 16-glucuronide and estradiol 17-glucuronide, respectively, exhibiting no significant cross-reactions with estrogen glucuronides having a substituent in ring A and no cross-reactivities with free estrogens, their sulfates and related steroids.

Antibodies↗
PubMed1982

Properties of NADH-dependent estradiol 2-hydroxylase in rat liver.

The NADH-supported cytochrome P-450-dependent 2-hydroxylation of estradiol in rat liver microsomes has been investigated. Estradiol 2-hydroxylation proceeded well with NADH instead of NADPH as a cofactor. Dimethyltetrahydropterine was incapable of serving as a hydrogen donor for this biotransformation. When both NADH and NADPH were used, the 2-hydroxylation increased additively. Molecular oxygen dissolved in the incubation medium was enough for the occurrence of the NADH-dependent 2-hydroxylation. The presence of carbon monooxide suppressed the formation of catechol estrogen where the CO/O2 ratio needed for 50% inhibition of the bioconversion was 7.7. The inhibitory effect was reversed completely by illumination with white light. p-Chloromercuribenzoate inhibited almost completely the 2-hydroxylase activity, and the enzyme activity was also inhibited by SKF-525A. These results strongly imply the possible involvement of a cytochrome P-450 system in the NADH-dependent 2-hydroxylation of estradiol with rat liver microsomes.

Animals↗
PubMed1982

In vitro O-methylation of 4-hydroxyestrone monosulfates.

In vitro O-methylation of 4-hydroxyestrone monosulfates has been examined by means of high-performance liquid chromatography with electrochemical detection. When 4-hydroxyestrone or its 3-sulfate was incubated with rat liver homogenate in the presence of S-adenosyl-L-methionine, the 4-methyl ether was formed in twelve times larger amount than the 3-methyl ether. 4-Hydroxyestrone 4-sulfate served for O-methylation to much less extent as a substrate namely, only a small amount of the 4-methyl ether was formed. Enzymic sulfation of 4-hydroxyestrone with rat liver 105000 g supernatant fortified with adenosine 3'-phosphate 5'-phosphosulfate provided solely catechol estrogen 4-sulfates. The participation of catechol O-methyltransferase and aryl sulfatase in the formation of guaiacol estrogens has been discussed.

Animals↗
PubMed1982

The effect of ursodeoxycholic acid on biliary bile acid composition in patients with cholesterol gallstone.

To elucidate the role of conjugated biliary bile acids in gallstone dissolution, the acids in bile were determined by high-performance liquid chromatography before and after the treatment with ursodeoxycholic acid for 3-26 months in patients with gallstone. The stone-dissolving effect of ursodeoxycholic acid was confirmed in 7 of 10 patients and the lithogenic index lowered significantly after the treatment. The compositions of cholate, chenodeoxycholate and ursodeoxycholate were about 33, 45 and 4%, respectively, in the control and pre-treatment groups. In the post-treatment group, a markedly low value was observed in primary bile acids both glycine-conjugates and taurine-conjugates, especially in cholate, with a significantly high value of ursodeoxycholate (p less than 0.001) of both conjugates. On the other hand, no difference was observed in the composition of deoxycholate with significantly low percentage of taurine-conjugates compared with that in the pre-treatment group. The ratio of glycine- to taurine-conjugated bile acids showed a significantly higher value in the post-treatment group than in the pre-treatment group (p less than 0.001) and the control group (p less than 0.005). The bile specimens were measured concomitantly by gas-liquid chromatography and the results were compared with those of high-performance liquid chromatography. The mean value of total bile acids, the ratio of cholate to chenodeoxycholate and the ratio of glycine- to taurine-conjugated bile acids obtained by the former analysis procedure represented about 57, 80 and 115% of those of the latter. It is concluded that the high G/T value seems to have a role in the dissolution mechanism.

Adult↗
PubMed1981

Studies on steroids. CLXX. Separation and determination of bile acid 3-sulfates in human bile by high-performance liquid chromatography.

A method for the simultaneous determination of sulfated bile acids in human bile without prior hydrolysis and solvolysis is described. The sulfate fraction was obtained from a bile specimen by passing it through a Sep-Pak C18 cartridge, followed by group separation by ion-exchange chromatography on a lipophilic gel, piperidinohydroxypropyl Sephadex LH-20. Subsequent resolution into the 3-sulfates of unconjugated, glycine- and taurine-conjugated ursodeoxycholate, cholate, chenodeoxycholate, deoxycholate and lithocholate was attained by high-performance liquid chromatography (HPLC) on an SC-02 column. Separation of these sulfates was effected when acetonitrile-0.5% ammonium carbonate (8:31, 8:26 and 8:23, v/v) was used as mobile phase. The sulfated bile acids in human bile were unequivocally identified on the basis of their behaviour in HPLC using mobile phases of various PH values. The present method proved to be applicable to the characterization and quantitation of sulfated bile acids in human bile.

Bile↗
PubMed1981

Studies on steroids. CLXV. Determination of isomeric catechol estrogens in pregnancy urine by high performance liquid chromatography with electrochemical detection.

A method for the determination of 2- and 4- hydroxylated estrone and estradiol in pregnancy urine by high-performance liquid chromatography with electrochemical detection (HPLC-ECD) is described. The urine catechol estrogens were deconjugated, purified by adsorption on alumina, and subjected to HPLC-ECD. Two pairs of isomeric catechol estrogens were distinctly separated on a microBondapak c18 column with acetonitrile-0.5% ammonium dihydrogen phosphate (pH 3.0). The amounts of these four compounds were satisfactorily determined with a quantitation limit of 1 ng using 4-hydroxy-16 oxoestradiol 17 acetate as an internal standard. The validity of the present methods for the determination of urine catechol estrogens was verified by the recovery test.

Chromatography, High Pressure Liquid↗
PubMed1981

Characterization of aminoindamines and aminoindoanilines formed by oxidative hair dyeing and their mutagenicity.

2-Amino-5-methoxy-2'(or 3')-methylindamine and 2-amino-5-methoxy-2'(or 3')-methylindoaniline were isolated from a coloring matter formed by oxidative condensation of 2,5-diaminotoluene with 2,4-diaminoanisole, and their structures were elucidated on the basis of nuclear magnetic resonance and mass spectral data. These two main components of the oxidation product formed at the early stage exhibited a positive result in the mutagenicity test on the thin-layer chromatography plate. The mutagenic activities of purified aminoindamines and aminoindoanilines against Salmonella typhimurium TA 98 were as strong as that of 2-acetamidofluorene. It was also demonstrated that 5-methoxy-2'(or 3')-methylindamine was formed in 10% yield under the conditions used for hair dyeing and the yield was dependent upon the molar ratio of 2,5-diaminotoluene to 2,4-diaminoanisole.

Aniline Compounds↗