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Biomedical subjects

B Descomps

Publications and source records attributed to B Descomps.

At least 19 recordsLinked to original sources
PubMed1979

[Nycterohemeral variations of growth hormone and prolactin in 6 Parkinson's sufferers treated with bromocriptine (author's transl)].

Secretions of GH and of PRL studied over a period of 24 hours in 6 untreated Parkinson's patients showed slight changes. The normal secretion of PRL in the female shows no nocturnal increase in the male. The secretion of GH linked to sleep is identified in the male and not in the female. These variations related to sex are interpreted as an increase in those normally found in the adult and facilitated by age. Bromocriptine given continuously at a dose of 10 to 20 mg/day for periods of 20 days to 6 months, results in suppression or a marked decrease in the 24-hour secretion of PRL. It has virtually no effect upon the secretion of GH. These results show that the dopaminergic regulation of PRL is preserved in Parkinson's disease.

Aged↗
PubMed1979

Alkylation of estradiol 17 beta-dehydrogenase from human placenta with 3-chloroacetylpyridine--adenine dinucleotide phosphate.

3-Chloroacetylpyridine--adenine dinucleotide phosphate is both active as a hydride acceptor and inactivates estradiol 17 beta-dehydrogenase. This coenzyme analogue behaves like an affinity label. The inactivation kinetics are discussed in relation to those observed with 3-chloroacetylpyridine--adenine dinucleotide. The pH dependence of the rate of inactivation, in combination with determination of the number of reactive cysteine residues, pointed to the alkylation of one cysteine residue/subunit. The stoichiometry was one molecule of dinucleotide per subunit and no cooperativity was detected. When 14C-labeled dinucleotide was used, the 14C label was found mainly in one peptide, accounting for 90% of the incorporated radioactivity, whereas in previous work it had been shown that 3-chloroacetylpyridine--adenine dinucleotide is an affinity reagent which labels three peptides.

17-Hydroxysteroid Dehydrogenases↗
PubMed1979

Enzymatic determination of estradiol and estrone in plasma and urine.

Plasma and urine estradiol and estrone can be determined using the transhydrogenase function of the estradiol dehydrogenase of human placenta: in the conditions described the transhydrogenase activity which is directly related to the estrogen concentration is measured by spectrophotometry. Estrone and estradiol can be determined together or separately if estrone is previously reacted with hydrazine with a limit of sensitivity of 10 picograms in the sample. On urine samples the assay is performed directly without extraction, a simplification which makes the method highly suitable for numerous routine determinations.

Estradiol↗
PubMed1979

[Postoperative analgesia by constant flow injection of lignocaine in obstetrical and gynecologic surgery].

154 surgical patients were given post-operative analgesia by peridural injection at a constant flow in the post-operative period after obstetric or gynecological surgery. These patients received 536.2 +/- 105.3 mu mol.h-1 (145.2 +/- 28.5 mg.h-1) of lignocaine for 46.97 +/- 15.56 h through a catheter omserted between L1-L2. The drug was given in concentrations which varied between: 27.7 to 18.5 m mol.l-1 (0.75 to 0.50 p. 100) depending on the age; and the volume varied between 17.5 to 30 ml.h-1 depending on the height. Satisfactory analgesia in 87 p. 100 of cases allowed all supplementary analgesia to be stopped. The only significant hemodynamic effect was a slight tachycardia (+ 15 p. 100). Two undesirable side effects were noted: a transitory but well-defined (type 2 or 3) motor paralysis, and an accumulation of plasma lignocaine (40 mu mol.l-1 (1.1 microgram.ml-1) at 48 h).

Analgesia↗
PubMed1978

Plasma acetate levels during hemodialysis.

Before dialysis, acetate levels in hemodialyzed patients (0.27--1.1 mmol/1) were more dispersed than in normal subjects (0.20--0.65 mmol/l) and the mean value of plasma acetate was slightly higher (0.52 mmol/l versus 0.31 mmol/l). Though dialysis conditions were almost identical, the acetate kinetics during hemodialysis were very different: in most subjects, plasma acetate concentrations reached a "plateau" (mean value 5.6 mmol/l) whereas in others a continuous rise was observed, suggesting that with patients having chronic renal failure there were important individual or occasional differences in the ability to metabolize acetate. The acetate loads per minute (or mass transfers) were calculated from the blood compartment with plasma values (plasma flow and concentrations), rather than from the dialysate and using the combined calculations (plasma and whole blood values). The results ranged between 2.4 and 4.1 mmol/min. A very important and rapid fall in arterial acetate concentrations occurs in the first 20 min after the end of the dialysis and proves the rapid turnover of the acetate in man.

Acetates↗
PubMed1978

Structural requirements for maximal inhibitory allosteric effect of estrogens and estrogen analogues on glutamate dehydrogenase.

The inhibition of glutamate dehydrogenase by estrogens, estrogen analogues or polyphenylethylene derivatives (about one hundred molecules, most of them having estrogenic or antiestrogenic activities) was measured. The efficiency of these compounds in inducing allosteric inhibition of the enzyme was compared and correlated to their chemical structure: an aromatic ring A, a free phenolic group in the region of carbon 3 of the steroid nucleus and a lipophilic substitution in the region of C-12, C-13 or C-17 were found to be the main structural features required for maximal efficiency on glutamate dehydrogenase. A tentative model for the relative orientation of the main inhibitor families is proposed. It accounts for most of the kinetic results and can be used as a tool for the selection of affinity labels directed towards the estrogen binding site of glutamate dehydrogenase.

Allosteric Site↗
PubMed1978

Affinity labelling of the estrogen binding site of glutamate dehydrogenase with iodoacetyldiethylstilbestrol. Selective alkylation of cysteine-89.

Iodoacetyldiethylstilbestrol was used as an affinity label to alkylate the estrogen binding site of bovine liver glutamate dehydrogenase. This reagent induced inactivation and alkylation of the enzyme. The non-alkylating analogues diethylstilbestrol and estradiol protected the enzyme towards alkylation. The apparent constant of alkylation was of the order of magnitude of I50 for the allosteric inhibition by diethylstilbestrol. These two results suggest that alkylation occurred at the estrogen binding site. The stoichiometry of alkylation was between one and two, depending on the experimental conditions. When the stoichiometry was found to be less than or equal to 1, 90% of the label was bound on cystein residues, 70% of which was carried by cysteine-89, a cysteine residue which is known to be inacessible to iodoacetamide in phosphate buffer in the same conditions of temperature and pH.

Affinity Labels↗
PubMed1977

Characterisation of an associate 17-beta-hydroxysteroid dehydrogenase activity and affinity labelling of the 3-alpha-hydroxysteroid dehydrogenase of Pseudomonas testosteroni.

The 3-alpha-hydroxysteroid dehydrogenase and the 3-beta-hydroxysteroid dehydrogenase of Pseudomonas testosteroni were purified to homogeneity by polyaerylamide gel electrophoresis using the following stages: DEAE cellulose chromatography, affinity chromatography on oestrone-aminocaproate sepharose and Sephadex gel filtration. The pure 3-alpha-hydroxysteroid dehydrogenase was completely devoid of 3-beta-hydroxysteroid dehydrogenase activity but could oxidize estradiol 17-beta at an appreciable rate. This activity accounts for about 40 per cent of the total 17-beta-estradiol dehydrogenase of the crude bacterial extract. Affinity labelling of pure 3-alpha-hydroxysteroid dehydrogenase was carried out using 5-beta-pregnane 3,20-dione-12-alpha-iodoacetate and 5-alpha-androstane 3-one-17-beta-bromoacetate. With both reagents, inactivation was obtained only in the presence of coenzyme, the substrate protected against inactivation and the enzyme was fully inhibited with covalent binding of 1 mole of reagent per mole of subunit suggesting an active site directed inhibition. Histidine and methionine were identified as the labelled aminoacid residues.

17-Hydroxysteroid Dehydrogenases↗
PubMed1977

[Plasma prolactin levels in normal children from birth to adolescence].

Plasma prolactin levels were determined by an homologous radio-immuno assay in normal children: in cord blood, at the first day of life, during childhood and along puberty. 1. In both sexes, there is a very important secretion of prolactin during the neonatal period. 2. Longitudinal studies make obvious a different pattern of plasma prolactin in boys and in girls at puberty.

Adolescent↗