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Biomedical subjects

T Nambara

Publications and source records attributed to T Nambara.

At least 127 records · Page 7Linked to original sources
PubMed1984

Conjugated oestrogen during the menstrual cycle measured by a direct radioimmunoassay with an antiserum prepared against oestradiol-17-glucosiduronate-[C-6]-BSA conjugate.

Early morning and 24 h urine samples and serum were collected daily throughout the menstrual cycle in women. Urinary oestradiol-17-glucosiduronate (E2-17-G) was measured with a direct radioimmunoassay whose antiserum had been prepared against E2-17-G-[C-6]-bovine serum albumin conjugate and was very specific. On the average, E2-17-G in early morning and 24 h urine samples showed a prominent peak one day before the peak of urinary LH. The time relationship between these urinary E2-17-G and serum E2 levels and peaks was also investigated.

Adult↗
PubMed1984

Estradiol-17 beta and estradiol-17-glucosiduronate before and at delivery.

The maternal peripheral serum level of estradiol-17 beta (E2), which reaches a peak a few weeks before delivery, may play a role in initiating delivery. In this study, the steroidal activity regulated by both the production and conjugation was estimated by measuring estradiol-17-glucosiduronate (E2-17-G), E2, estriol-16-glucosiduronate (E3-16-G), and estriol (E3) before and at delivery. At delivery, levels of E2 and E2-17-G were higher in the maternal peripheral vein (MP) than in the umbilical vein (UV) and umbilical artery (UA), but those of E3 and E3-16-G were higher in UV and UA than in MP. These results suggested that the production and conjugation of E2 were mainly regulated on the maternal side, but those of E3 were regulated mainly in the feto-placental unit. The ratios of E2/E2-17-G in MP were or became high a few weeks before delivery but decreased remarkably as pregnancy progressed to delivery. The activity of E2 seems to be regulated at least in part by conjugation in late pregnancy and at delivery.

Cross Reactions↗
PubMed1983

Studies on steroids. CLXXXVII. Determination of serum bile acids by high-performance liquid chromatography with fluorescence labeling.

A method for the simultaneous determination of bile acids in serum by high-performance liquid chromatography (HPLC) with fluorescence labeling is described. The bile acid fraction was obtained from a serum specimen by passing it through a BondElut cartridge. Bile acids were derivatized quantitatively into the fluorescent compounds through the hydroxyl group at C-3 by treatment with 1-anthroyl nitrile in the presence of quinuclidine in acetonitrile. These derivatives were separated into the free, glycine- and taurine-conjugate fractions by ion-exchange chromatography on a lipophilic gel, piperidinohydroxypropyl Sephadex LH-20. Subsequent resolution of each fraction into cholate, ursodeoxycholate, chenodeoxycholate, deoxycholate and lithocholate was attained by HPLC on a Cosmosil 5C18 column using 0.3% potassium phosphate buffer (pH 6.0)--methanol (1:5) and 0.1% potassium phosphate buffer (pH 6.0)--methanol (1:8) as mobile phases. The anthroyl bile acids were monitored by fluorescence detection (excitation wavelength 370 nm; emission wavelength 470 nm), the limit of detection being 20 fmol. The proposed method proved to be applicable to the quantitation of bile acids in serum with satisfactory reliability and sensitivity.

Bile Acids and Salts↗
PubMed1983

The simultaneous determination of serum cortisol and cortisone by high-performance liquid chromatography with fluorimetric detection.

A new method for the simultaneous determination of cortisol and cortisone in serum by high-performance liquid chromatography with fluorimetric detection has been developed. The two steroids were derivatized by treatment with 9-anthroyl nitrile in triethylamine-acetonitrile to give the fluorescent esters through the 21-hydroxyl group. These derivatives were efficiently separated on a straight-phase Cosmosil 5SL column with hexane-ethyl acetate (6:5) as eluent. The detection limit was 20 fmol, using the 9-anthroyl derivative of prednisolone as an internal standard. The use of Sep-Pak C18 and Clin-Elut cartridges proved to be efficient for the clean-up of cortisol and cortisone in serum samples.

Journal Article↗
PubMed1983

Antigenic properties of estriol 3-glucuronide-[C-6]-bovine serum albumin conjugates having oxime bridges.

The preparation and antigenic properties of estriol 3-glucuronide-bovine serum albumin (BSA) conjugate in which the hapten is linked to the carrier protein through an (O-3-carboxypropylcarbamoylmethyl)oxime bridge at the C-6 position on the steroid nucleus, has been described. 16,17-Di-O-acetyl-6-oxoestriol 6-(O-carboxymethyl)oxime 3-glucuronide acetate-methyl ester was condensed with gamma-amino-n-butyric acid by the mixed anhydride method. Subsequent coupling with BSA followed by removal of the protecting groups with alkali gave the desired hapten-BSA conjugate. The antisera elicited in the rabbit with the conjugate were highly specific to estriol 3-glucuronide, discriminating from other 3-substituted compounds. The specificity of antisera improved by elongation of the 6-(O-carboxymethyl)oxime bridge has been discussed.

Animals↗
PubMed1982

Studies on steroids. CLXXIX. Determination of estriol 16- and 17-glucuronide in biological fluids by high-performance liquid chromatography with electrochemical detection.

A high-performance liquid chromatographic method for the determination of estriol 16-glucuronide and 17-glucuronide in bile and urine has been developed. The electrochemical detector was found to be more superior than the UV detector with respect to selectivity and sensitivity and therefore more suitable for the determination of estrogen conjugates in biological fluids. The use of the present method revealed that both estriol 16-glucuronide and 17-glucuronide were excreted in rat bile, while only the former was present in human pregnancy urine.

Animals↗
PubMed1982

Determination of estrone sulfate in plasma by radioimmunoassay without deconjugation.

A radioimmunoassay method using highly specific antiserum without prior deconjugation has been developed for determination of estrone sulfate in human plasma. Antiserum was elicited in the rabbit by immunization with antigen in which the sulfated steroid hapten is linked to a carrier protein through the C-6 position. After treatment with Rivanol, the protein of albumin-free antiserum was covalently bound to a p-arylamine glass bead support through the cross-linkage with glutaraldehyde. A simple and reliable method for measurement of estrone sulfate which involves elimination of endogenous interferences by use of Sep-pak C18 followed by radioimmunoassay employing the antibody-glass preparation, was established and applied to peripheral plasma throughout normal pregnancy.

Animals↗