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Biomedical subjects

M F Jayle

Publications and source records attributed to M F Jayle.

At least 19 recordsLinked to original sources
PubMed1981

[Evidence, in vitro, of estrone and estradiol-17 beta 3-sulfoconjugate hydrolysis in the uterus of pregnant guinea pigs].

The metabolism, in vitro, of [6,7-3H]-oestrone-3-sulfate and [6,7-3H]-oestradiol-17beta-3-sulfate by the uteri of pregnant female Guinea-Pigs has been studied using 900 g supernatants. A hydrolysis of the sulfate moiety was observed: 35% of the radioactivity was recovered in the unconjugated fractions after 1 hr. of incubation. Gluruconide oestrogens were also recovered but the rate of synthesis was very low (3.6% after 1 hr.). OEstrone and oestradiol-17beta have been identified in unconjugated, glucuro and sulfo-conjugated fractions after incubation with the tritiated oestrogen sulfates.

Animals↗
PubMed1980

The preparation of three fluorescence-labeled derivatives of testosterone.

Three fluorescence-labelled derivatives of testosterone were prepared consisting of the steroid separated from the fluorochrome by a hydrocarbon "bridge". "Bridges" of different lengths (C2 to C7) were used as the length required to avoid steric hindrance effects by the fluorochrome in studies on steroid-protein binding was unknown. The three derivatives prepared were: 17 beta-hydroxy--4-androsten-3-one 3-(O-(N-(2'-mercapto)ethyl)carbamoylmethyl)oxime, 17 beta-hydroxy-4-androsten-3-one 3-(O-(N-(3'-amino)propyl)carbamoylmethyl)oxime and 17 beta-hydroxy-4-androsten-3-one 3-(O(N-(7'-amino)heptyl)carbamoylmethyl)oxime. These were then coupled with either a dansyl or a fluorescein molecule. Overall yields were sufficient and the products immunoreactive with anti-testosterone antiserum.

Chemical Phenomena↗
PubMed1980

[In vitro aromatization of androgens in the presence of testosterone binding proteins from human placenta or serum].

Two related 17 beta hydroxy steroid binding proteins of serum and placental origin respectively are shown to inhibit significantly the aromatization of testosterone and androstenedione by isolated human placenta microsomes. Quantitative correlations suggest that this inhibitory effect is due to the fixation of the testosterone substrate (or androstenedione previously converted to testosterone) on the binding proteins. A possible role for these macromolecules in the steroidogenic activity of the placenta is discussed.

Androstenedione↗
PubMed1980

Kinetic study of the interaction between rat haptoglobin and rat liver cathepsin B.

One of the roles of the acute phase reactants (APR), according to Koj, is to regulate the action of tissue proteinases released during the inflammatory reaction. To study this phenomenon in vitro, rat liver cathepsin B (EC 3.4.22.1), a lysosomal proteinase, and a typical APR, rat serum haptoglobin, were purified. By kinetic study, haptoglobin was found to inhibit cathepsin B and the inhibitory activity of a competitive type was increased with the molecular weight of the substrate. When 125I-labelled denatured bovine serum albumin (BSA) was used as a substrate, the apparent Michaelis constant (Km app.) for cathepsin B was 5 +/- 0.4 X 10(-6) M. When haptoglobin was added, the apparent inhibition constant (Ki app.) was 3.5 +/- 1.5 X 10(-8) M. Native haptoglobin was not catabolized by cathepsin B while under the same conditions denatured haptoglobin was degraded by the enzyme.

Animals↗
PubMed1980

Semi-automated fluorometry of total estrogens in plasma during late pregnancy.

We describe a mechanized method for determining total estrogens in plasma during the last trimester of pregnancy. This method involves rapid enzymic hydrolysis, automatic extraction (in a tube) with cyclohexane/ethyl acetate, purification of the extracted material by anion-exchange chromatography on a disposable "mini-column" of Dowex AG1 X 2 (acetate form), and continuous-flow fluorometric quantification. Conditions of hydrolysis and extraction were studied. The mean within-day imprecision (CV) was 7% and between-day imprecision was 8.1%. Sensitivity was 75 nmol/L of plasma. Results are obtained in 4 h. The technique is quite suitable for routine determinations: 90 assays can be done by a team of three technicians in one working day.

Estrogens↗
PubMed1979

Identification of haptoglobin in chicken serum and specificity of the chicken haptoglobin-hemoglobin complex formation.

1. The presence of haptoglobin in chicken serum has been demonstrated by three different techniques: gel filtration, cellulose acetate electrophoresis and fluorescence quenching. 2. Chicken haptoglobin shows a narrow species specificity; it binds only avian and reptilian but not mammalian hemoglobins. 3. Haptoglobin seems to have been subjected to profound changes during the course of evolution.

Animals↗
PubMed1979

Rapid fluorometry of estrogens in nonpregnancy urine, with use of chloroform extraction and purification by anion-exchange chromatography.

We describe a new method of extraction and purification of estrogens in low concentration in urine, involving a rapid enzymic hydrolysis of a 10-mL sample, automatic extraction (in a tube) with CHCl3/ethyl acetate, purification by chromatography on a disposable "mini-column" of AG 1-X2, and fluorometry by continuous flow according to Itrich's procedure [Acta Endocrinol. (Copenhagen) 35, 34 (1960)]. Conditions of hydrolysis, extraction, and purification were studied. Within-day precision (CV) was 7.5%, the mean between-day precision 8.5%. The sensitivity was 6 microgram of total estrogens per liter of urine. The specificity was assessed particularly by comparison with the results obtained by Schöller et al. [Acta Endocrinol. (Copenhagen) 57, suppl. 107 (1966)] and by gas-chromatography-mass-spectrometry. The normal limits as calculated by this technique were identical to values reported by others. The technique is rapid; results are obtained in 3 h. It is quite suitable for routine determinations: 100 assays can be done by a team of three technicians in one working day.

Chloroform↗
PubMed1979

[An automated spectrofluorometry method for urinary estrogens determination in pregnant and non-pregnant subjects (author's transl)].

An automated method has been developed for the measurement of estrogens in the urine of pregnant and non-pregnant subjects. Using the Kober-Ittrich fluorescence procedure, this automated method was applied to the assay of estrogens in the purified urinary extracts of non-pregnant women, men or children. For pregnant-women it had been possible to simplify the purification of urinary extracts, and the reaction was performed directly on the sodium hydroxide fraction. The precision, accuracy, and sensitivity of the method had been analysed.

Autoanalysis↗
PubMed1978

Fluorescence studies of the interactions of serum albumin and rat alpha1-fetoprotein with aflatoxin B1. Specificity and binding parameters.

The interaction of bovine serum albumin and rat alpha1-fetoprotein with aflatoxin B1 has been followed by the fluorescence quenching of the protein in presence of the ligand. The binding parameters (n, number of sites and Kd, dissociation constant) have been determined for the bovine serum albumin-alflatoxin B1 system: n = 3.5 and Kd = 3.1 +/- 0.5 . 10(-5) M and for the alpha-fetoprotein-aflatoxin system: n = 4 and Kd = 3.7 +/-0.5 . 10(-5) M. The competition of anilino-naphthalene-sulfonate and aflatoxin B1 for the same hydrophobic sites on bovine serum albumin has been demonstrated. The fluorescence quenching of various proteins (lysozymes, egg-albumin, gamma-globulin) by aflatoxin B1 have shown that there is not a strict specificity of aflatoxin towards proteins.

Aflatoxins↗
PubMed1978

Conversion, in vitro, of (7n-3H) testosterone to estrone and estradiol-17beta and their 3-sulfate conjugate by the guinea-pig placenta.

Different cellular fractions of guinea-pig placenta were incubated in the presence of (7n-3H) testosterone. Microsomal aromatization of 3H-testosterone into estrone and estradiol-17beta was demonstrated in the presence of NADPH. The predominance of estrone after incubation with 17beta-hydroxylated precursors, (7n-3H) testosterone and (6,7-3H) estradiol-17beta, indicate that there is a microsomal 17beta-hydroxysteroid dehydrogenase activity. In this report, cytosolic sulfurylation of estrogens is demonstrated. This latter activity represents a quite original characteristic of the placental metabolism of estrogens in guinea-pigs. In contrast with the human placenta where there is considerable sulfatase activity, the guinea-pig placenta can sulfurylate estrogens.

17-Hydroxysteroid Dehydrogenases↗
PubMed1978

[In vitro comparative metabolism of 6,7-3H estrone and 6,7-3H estrone-3-sulfate in maternal and fetal guinea-pig liver].

The metabolism of [6,7-3H] estrone and of [6,7(3)H] estrone-3-sulfate have been comparatively studied in the maternal and fetal guinea-pig livers. The appearance of estradiol-17 beta resulting from the activity of the 17 beta-hydroxysteroid-dehydrogenase is more important in the fetal than in the maternal hepatic tissue. This suggests the direct transformation of estrone-3-sulfate into estradio-3-sulfate in the fetus. After incubation of the [3H] estrone, there is an abundant hepatic conjugation. The glycuroconjugated components are predominant, as well in the maternal as in the fetal hepatic tissue. For the latter-one the sulfoconjugation is inexistant. The sulfatasic activity shown after the incubation of [3H] estrone-3-sulfate is very low in the fetal hepatic tissue; in contrast, this activity is higher in the maternal tissue.

Animals↗
PubMed1977

The conjugation of testosterone with horseradish peroxidase and a sensitive enzyme assay for the conjugate.

The formation of a horseradish peroxidase-testosterone conjugate for the enzyme-linked immunoassay of testosterone was investigated, using tritiated testosterone to follow the reaction. The formation of testosterone-3-(carboxymethyl) oxime-peroxidase by the mixed anhydride method was found to give a conjugate of high enzymatic activity and with three molecules of testosterone per molecule of peroxidase. The optimum conditions for the assay of peroxidase activity were studied and an assay capable of measuring 1 to 5 ng of the conjugate developed; the standard curve being virtually linear. The stability of the conjugate in solution and the effect of lyophilisation on enzymatic activity are also described. The peroxidase-testosterone conjugate was suitable for enzyme-linked immunoassay and the quantities measurable with the peroxidase assay covered the range necessary for a plasma testosterone assay. The stability of the conjugate was such that no particular precautions were necessary for its storage.

Aminosalicylic Acids↗