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H Raynal

Publications and source records attributed to H Raynal.

4 recordsLinked to original sources
PubMed1991

Effect of L-dopa loading on 5-HTP decarboxylation in rat brain areas.

The time course of 5-hydroxytryptophan (5-HTP), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in four rat brain areas (hypothalamus, hippocampus, striatum and olfactory bulbs) were investigated after treatment with L-dopa (125 mg/kg, ip) + benserazide (50 mg/kg, ip). 5-HTP levels increased as early as 0.5 h, showed maximum accumulation at 1.5 h and returned to control levels within 4 h, while 5-HT was markedly decreased in all four structures, with a maximum effect at 1.5 h (approximately -70%) in the four areas. The decrease in 5-HT was not accompanied by changes in 5-HIAA levels. In agreement with previous studies, these data demonstrate that L-dopa loading interferes with serotonin metabolism in the rat brain. However, in addition to the releasing action of newly-synthesized dopamine, the accumulation of 5-HTP and the parallel decrease in 5-HT indicate a reduction in 5-HT synthesis. This inhibition could be explained by a competitive effect of L-dopa for aromatic aminoacid decarboxylase activity.

5-Hydroxytryptophan↗
PubMedDate not supplied

Acne-like eruption induced by pseudoxanthoma elasticum: effectiveness of liquid nitrogen cryotherapy.

We report a case of pseudoxanthoma elasticum associated with an acneiform eruption involving the cervical area. When she was 16 years-old our patient was diagnosed with pseudoxanthoma elasticum, affecting the skin (flexural, cervical and neck areas) and the eyes (bilateral ocular angioid streaks). Ten years later, acneiform lesions (inflammatory and comedones) developed on these lesions: - the inflammatory lesions were characterized by phagocytosis of pathological elastic fibers inducing granuloma - the histological aspects of pseudoxanthoma elasticum were observed around large comedones. This association is rarely reported and we think that atypical, cervical acneiform lesions may be an indication of pseudoxanthoma elasticum. The mechanism for this association is not clearly understood. In our case, Von-Kossa staining was negative for the granulomatous lesions and positive for the comedones: calcification could protect elastopathic fibers from phagocytosis. Treatment is difficult: anti-acneic treatments are not effective except for tetracylines, the anti-inflammatory effects of which can improve granulomatous lesions. As its efficacy has been reported in elastosis perforans serpiginosa, we used liquid nitrogen cryotherapy on the inflammatory lesions with good results (separation of epidermis from dermis perhaps promoting transepithelial elimination of the abnormal dermal elastic tissue).

Acne Vulgaris↗