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Biomedical subjects

T Nambara

Publications and source records attributed to T Nambara.

At least 91 records · Page 5Linked to original sources
PubMed1987

New derivatization method using ferrocene reagents for the determination of steroid glucuronides by high-performance liquid chromatography with electrochemical detection.

New derivatization methods using ferrocene reagents have been developed for the determination of steroid glucuronides by high-performance liquid chromatography with electrochemical detection. Condensation of glucuronides with 2-ferrocenylethylamine is effected in the presence of water-soluble carbodiimide and 1-hydroxybenzotriazole. The resulting amides show the satisfactory sensitivity at +0.45 V versus Ag/AgCl reference electrode, with a detection limit of 0.5 pmole. The present method is found to be applicable to the estimation of estrogen glucuronyltransferase activities and estrogen glucuronides in pregnancy urine.

Journal Article↗
PubMed1986

Studies on steroids. CCXIX. Separation and determination of 4-hydroxyoestriol monoglucuronides and monosulphates in biological fluids by high-performance liquid chromatography with electrochemical detection.

The separation and determination of 4-hydroxyoestriol monoglucuronides and monosulphates by high-performance liquid chromatography with electrochemical detection on a reversed-phase column has been carried out. The effects of the salt, composition and pH of the mobile phase on the resolution were investigated with a Develosil ODS-5 column. Each group of isomeric monoglucuronides and monosulphates of 4-hydroxyoestriol was efficiently resolved on this column when 0.5% sodium acetate-acetonitrile and 0.5% sodium acetate-tetrahydrofuran-acetonitrile were used as mobile phases, respectively. The use of the present method revealed that 4-hydroxyoestriol orally administered to the rat was excreted as 4-, 3-, 16-glucuronides and 4-sulphate in bile.

Animals↗
PubMed1986

Structure-activity relationship of cardiac steroids having a doubly linked sugar and related compounds for the inhibition of Na+,K+-adenosine triphosphatase.

Forty-three different cardiac steroids having a doubly linked sugar and related compounds were tested for inhibition of Na+,K+-adenosine triphosphatase from guinea pig heart, and the structure-activity relationship has been discussed. The doubly linked glycosides showed higher activities than the respective genins. The inhibitory activities of these compounds were also dependent upon the presence of ring C substituents. The bufadienolide rhamnosides exhibited greater than three times the inhibitory activity of the parent genin, while the glucosyl residue exerted no significant activity.

Animals↗
PubMed1986

Serum and urinary oestrone sulphate in pregnancy and delivery measured by a direct radioimmunoassay.

Serum and urinary levels of oestrone sulphate in pregnancy and delivery were measured by a direct radioimmunoassay without hydrolysis. The serum and urinary oestrone sulphate increased as pregnancy progressed. The mean level of serum oestrone sulphate increased to the highest peak of 494 pmol/ml at the 35th gestational week and then decreased. The mean level of urinary oestrone sulphate increased to the highest peak of 1.28 mumol/l at the 34th gestational week and then decreased. At vaginal deliveries, the mean level of maternal peripheral serum oestrone sulphate increased hourly at as high a level as 979 pmol/ml. The mean serum level of oestrone sulphate was 204 pmol/ml in the umbilical artery and 145 pmol/ml in the umbilical vein. At Caesarean section, on the other hand, the maternal peripheral serum level of oestrone sulphate averaged 362 pmol/ml. The mean serum levels of oestrone sulphate were 90.7 pmol/ml and 171 pmol/ml in the umbilical artery and umbilical vein, respectively. These results suggest a maternal origin of oestrone sulphate in pregnancy, with fluctuations in the levels being of interest in relation to labour pain.

Cesarean Section↗