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Biomedical subjects

J Robert

Publications and source records attributed to J Robert.

At least 505 records · Page 28Linked to original sources
PubMed1976

[Diagnostic value of localized hypofixations in the radioisotope scanning of bones].

The scintigraphic appearances of all localized, evolutive bone lesions, whatever their nature, is usually a "hot spot", that is a zone of hyperfixation of the radioactive material. False negatively scintigraphs are, however, noted: the scintigraphic image appears normal, without a zone of hyperfixation, although radiographs of the skeleton are pathological. The 8 cases presented in this article demonstrate that certain bone lesions (aseptic osteonecrosis and malignant destruction of bone) may sometimes be represented as real zones of hypofixation, as veritable "cold spots". These areas of hypofixation result from either a local interruption in the vascularization, which prevents the isotope from reaching the bony structures, or from a quantitative insufficiency of the bony tissue, this being replaced by neoplastic tissue which, in the cases studied, fixed labelled Bleomycin or iodine-131. These areas of hypofixation and any absences of fixation really are the scintigraphic images of areas of osteolysis or of aseptic osteonecrosis but they are generally masked by hyperfixation around the lesion that results in reactional osteogenesis and hypervascularization.

Aged↗
PubMed1975

Catecholamine histofluorescence in the median eminence of female rabbits activated by mating.

Mating was used in the rabbit as a physiological trigger, easily definable in time, for the activation of gonadotropic hypothalamic structures. Using the histochemical fluorescence technique of Falck and Hillarp, it has been attempted to determine whether, in relation to mating, clearly distinuishable and reproducible changes in histofluorescence occur in the tuberoinfundibular dopaminergic system in combination with hypothalamic hypophysiotropic hormone release. Between 20-30 min post-coitum an increase in DA turnover was noted in the external layer of the median eminence. The characteristics of this reaction were studied by administration of reserpine and alpha-methyl-paratyrosine. Immediately after coitus, a paradoxical fluorescence reactivation was observed in the median eminence in female rabbits in which tyrosine-hydroxylase activity was inhibited for 5 hours.

Animals↗