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Biomedical subjects

F Dray

Publications and source records attributed to F Dray.

At least 145 records · Page 8Linked to original sources
PubMed1977

The use of iodinated tracers for a sensitive radioimmunoassay of 13,14-dihydro-15-ketoprostaglandin Falpha.

Radioimmunoassay of 13,14-dihydro-15-ketoprostaglandin Falpha is reported using various 125I-labelled derivatives. The apparent association constants of the antiserum for iodinated tracers are higher than with the homologous hapten. In spite of this, the high specific activities of iodinated tracers (2000 Ci/mmol) allow a 3-fold increase in the sensitivity of the assay when compared with the tritiated derivative. Human plasma levels of 13,14-dihydro-15-ketoprostaglandin Falpha reported (25+/-6 pg/ml) are lower than those previously found by radioimmunoassay, and no sexual difference was found.

Binding Sites↗
PubMed1977

Prostaglandins in the isolated testicular capsule of immature and young adult rats.

The presence of prostaglandins (PGs) E1, E2, F1alpha, F2alpha and the metabolite 13,14-Dihydro-15-keto PG Falpha (1+2) has been studied in the isolated testicular capsule of Wistar rats (22 to 90 days of age). Handling and homogenization of tissues were controlled and the in vitro synthesis and degradation were prevented by immediate freezing of samples and homogenization in a solution containing a PG synthetase inhibitor. The PGs were measured by specific and sensitive radioimmunoassay. The isolated rat testicular capsule was found to contain mainly PG E2 and PG F2alpha at concentrations about 100 times higher than those in decapsulated testes (ng/g of tissue).

Age Factors↗
PubMed1977

FSH: II. Evidence for its mediating role on testosterone secretion in hypopituitarism.

Testicular responses to administration of human chorionic gonadotrophin (HCG) in 23 hypopituitary patients were compared to responses obtained in adequate control groups and correlated to basal plasma follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels. Sixteen nonpubertal patients demonstrated a significantly diminished testosterone response (250 +/- 64 ng/100 ml, mean +/- SEM) along with low basal plasma FSH values (1.4 +/- 0.2 mU/ml) when compared to normal response (607 +/- 97 ng/100 ml) and normal FSH level (2.3 +/- 0.2 mU/ml), but with normal LH values. In 7 pubertal patients decreased testosterone responses to HCG (815 +/- 147 ng/100 ml) were observed with normal plasma FSH and LH values. Correlation between testosterone responses and FSH levels (r - 0.718, P less than 0.002) in the pre-pubertal hypopituitary patients was highly significant. No such correlation was observed between testosterone response and LH. The represent findings may a) give one explanation for the absence of response to HCG observed in some cases of hypopituitarism, b) give support to the hypothesis that FSH has a mediating role on LH-induced secretion of testosterone by the testis in human subjects.

Adolescent↗
PubMed1976

[Determination of the ecdysone level in the molting cycle of the crab, Carcinus moenas: comparison between healthy individuals and those parasitized by Sacculina carcini].

Radioimmunoassay is performed for a quantitative study of ecdysone in Carcinus moenas. Two periods can be determined in the moulting cycle. In haemolymph from ecdysis until beginning D0 stage, the moulting hormone content is not very high; from D0 stage until D4 stage, the hormone titer rises considerably. We can observe a similar rise in hormone content in both haemolymph and Y organ during the premolt stages. In sacculinized Crabs, the determined values of ecdysone in haemolymph and in Y organ are lower than those determined in healthy animals at the same stage.

Animals↗
PubMed1976

[Changes in the level of ecdysones in the last 2 instars of Panstrongylus megistus (Heteroptera: Reduviidae)].

The ecdysone titre in the hemolymph during the two last instars of P. megistus was studied by radio-immunology technique. Changes observed are very similar in both instars. Two peaks of inequal amplitude are present. The first, always lower than the second, occurs at 1/3 of the intermoult whereas the second, distinctly higher, is observed at 2/3 period of the intermoult.

Age Factors↗
PubMed1976

Primary prostaglandins in amniotic fluid in pregnancy and spontaneous labor.

Primary prostaglandins have been measured by radioimmunoassay in the amniotic fluid of 80 patients. In late pregnancy, PGE2 was higher than PGF2alpha with an increase around 36 weeks (378 +/- 71 pg. per milliliter) without significant modification until term. PGF2alpha increased too, but only significantly at term. During spontaneous labor, PGE2 and PGF2alpha were higher than before the onset of labor. Through serial determinations in five patients, two steps can be distinguished: the first one with stable levels but large oscillations of PGE2 and PGF2alpha and the second one starting at a variable stage of cervical dilatation with inversion of PGE2/PGF2alpha ratio (less than 1 and followed by an increase of both compounds more pronounced for PGF2alpha. It appears that PGE2 is concerned with the initiation of parturition while both PG's and mainly PGF2alpha are in relation to the contractions and the duration of labor.

Amniotic Fluid↗
PubMed1976

125I derivatives of prostaglandins. A novel approach in prostaglandin analysis by radioimmunoassay.

We report the production of radioactive iodinated (125 I) derivatives of prostaglandins E1, E2, F2alpha and their use in radioimmunological assays. Histamine or tyramine was coupled to the prostaglandins carboxyl group and the iodination was accomplished using the chloramine T method. The high specific radioactivity of these tracers and the resolution of the purification procedure allowed the detection of 0.5 pg of prostaglandins. A comparison with tritiated prostaglandin was made and showed a 10-fold gain in sensitivity. Furthermore in the case of the prostaglandin E1 system using 125I-labelled histamine or tyramine as tracer the cross reaction curves obtained were different from those obtained with [3H]prostaglandin E1; we suggest that the blocking of the carboxyl group alters the prostaglandin E1 structure, modifying its immunoreactivity.

Amniotic Fluid↗
PubMed1976

[Study of prostaglandin synthesis during anaphylactic shock in guinea pigs].

In guinea pigs actively sensitized with ovalbumin and shocked, we have measured blood histamine and histaminase, pulmonary content in cycli AMP and prostaglandins (PG) E1, E2 and F2alpha. In pulmonary efferent blood, both PGE and PGF are increased. In lung tissue, only PGF2alpha, which are bronchoconstructive mediators, are increased. Th increased level in PG seems to have two origins: first a specific increase, then an increased synthesis secondary to histamine release.

Amine Oxidase (Copper-Containing)↗
PubMed1975

Enzyme immunoassay of progesterone at the picogram level using beta-galactosidase as label.

We report here the first sensitive enzyme immunoassay of a hapten. A progesterone beta galactosidase conjugate was prepared using carbodiimide as a bifunctional reagent. Rabbit progesterone antisera were previously obtained. The separation of the bound from the free fraction of the label was performed with the help of polymerized anti rabbit gamma-globulins. The enzyme activity of the bound fraction was determined with O-nitrophenyl-beta-D-galactoside as substrate. Specificity and sensitivity (approximately 15 pg) of this enzyme immunoassay can be successfully compared with radioimmunoassay performances. It thus provides a non radioactive, inexpensive and reliable method of small molecule quantitation.

Animals↗