Biomedical subjects
Publications and source records attributed to F Dray.
Application of specific radioimmunoassays to various extracts of the locust showed that nervous tissues and specially the optic lobes contain enkephaline-like material. However these immunoreactive substances present an apparent higher molecular weight (700--1 000 dalton) than those of the controls, as tested by chromatography on Sephadex G 25.
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Chronic catheterization of aorta and inferior vena cava in dogs did not significantly affect circulating levels of prostaglandins (PGE2 and PGF2alpha). Pentobarbital (30 mg/kg i.v.) anaesthesia produced a significant decrease in PGF2alpha.
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By using horseradish peroxydase (HRP) as a tracer, it is shown that the gonial region of the locust testis is an "open" compartment which is almost always freely penetrated by the tracer. During the last larval instar, however, the penetration of HRP decreases and ceases at the time when high levels of ecdysteroids are detected in the haemolymph by radioimmunoassay. A cause and effect relationship between tracer uptake and hormonal level could not be demonstrated by the experiments carried out up to now. From ultrastructural observations of the testis, it is concluded that the temporary isolation of the gonial compartment is not based upon any morphological structure which could act as a barrier. Penetration of the macromolecule is considered as the expression of an active uptake by the testis and the short period of nonpenetrability as a state of inertia whose significance remains to be discovered.
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A sensitive and specific radioimmunoassay using a 125I tracer of high specific radioactivity was developed for thromboxane B2 and was applied to the determination of the in vitro biosynthesis of this compound in some systems (i.e. human washed platelets, human platelet rich plasma (PRP) and rat spleen homogenates). The assays were also evaluated by mass spectrometry; levels measured by these two analytical methods were very similar. The results obtained for washed human platelets with a thin layer radiochromatographic method were in good agreement with the two preceeding methods.
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1. The daily urine excretion has been studied of prostaglandins (PG) E2 and F2alpha, as measured by radioimmunoassay, in eight children and seven adults with Bartter's syndrome. 2. Excretion of both PGE2 and PGF2alpha was significantly higher in the patients with Bartter's syndrome than in 17 normal children. 3. Twelve normal adults excreted significantly more PGE2 and PGF2alpha than did the normal children. In contrast, adults with Bartter's syndrome did not show an increase in prostaglandin excretion.
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The authors present a reliable and sensitive estimation of progesterone using a conjugate progesterone IIalpha-hémimaleate-beta galactosidase to identify the immunological reaction, the antibodies being obtained from the rabbit by means of a progesterone 11alpha-hemisuccinate bovine serum albumin. The free and bound fractions are separated by addition of rabbit antigamma globulin antibodies bound on glass beads by glutaraldehyde. This method is applied to estimations of cortisol and oestrone.
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A serotonine-sensitive adenylate cyclase system has been observed in horse brain membrane preparations. In crude mitochondrial fraction two types of activation sites were characterized, the Ka being = 2 nM and 1 micrometer. In purified synaptosomal membranes, a single adenylate cyclase activation was observed corresponding to the highest apparent affinity (KD = 2nM). This activation site might be related to the high affinity binding site (KD = 2NM) were previously described in the same membrane preparations.