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Biomedical subjects

F Gauthier

Publications and source records attributed to F Gauthier.

206 records · Page 12Linked to original sources
PubMed1970

Studies on testosterone metabolism in subjects with testicular feminization syndrome.

The metabolism of radioactive testosterone simultaneously administered intravenously and either orally or percutaneously has been studied in seven patients with the syndrome of testicular feminization and compared with that of normal males and females. This investigation was carried out in order to determine the relative contribution to urinary 17-oxo and 17beta-hydroxy androstane steroids of labeled testosterone, according to its mode of administration. In normal males the yields of urinary 5alpha-androstane-3alpha,17beta-diol (androstanediol) originating from either an intravenous or a percutaneous dose of testosterone were respectively 3 and 6 times higher than those arising from an oral dose which perfuses the liver directly. These data indicate that in normal males, testosterone might be 5alpha-hydrogenated outside the liver. By contrast in patient with feminizing testes, because the contribution to androstanediol of radioactive testosterone is identical whatever its mode of administration, the extrahepatic 5alpha-reduction of this substrate seems very unlikely. The metabolic abnormalities observed in patients with testicular feminization syndrome may be reproduced in normal males by estrogen treatment. Nevertheless, the sensitivity of the patients to estrogen seems to be 10 times greater than that of normal males. This sensitivity was appreciated from the reduction of radioactive testosterone intravenously injected to urinary 17beta-hydroxy-5alpha-androstan-3-one and androstanediol and also from the level of plasma binding for testosterone. This level was significantly higher (P < 0.05) in patients with feminizing testes than in normal males. The level increased dramatically after administration of a low dose of estrogen whereas this effect was not observed in normal males under the same experimental conditions. In light of these results the defect of extrahepatic 5alpha-reduction of testosterone observed in patients with feminizing testes does not necessarily reflect an enzymatic impairment but might be related to an abnormal synthesis of plasma binding protein(s) under the effect of circulating estrogens so that an abnormally small amount of unbound testosterone may be available in target cells for 5alpha-reduction.

Adult↗
PubMedDate not supplied

[An unusual cause of near-miss sudden death in infants: intermittent volvulus of the small intestine on the mesenterium commune].

A 1 month-old girl presented with severe asphyxia during sleep. Her weight was the same as at birth. The day before the accident she had cried a great deal and had vomited her feeds. Small bowel volvulus was diagnosed. Surgical cure led to the disappearance of all symptoms with a one year follow-up. Episodes of asphyxia require detailed histories. Alkaline esophageal reflux may reveal an anatomic intestinal obstruction and lead to laryngospasm, identical to the one induced by acid reflux.

Asphyxia↗
PubMedDate not supplied

Potential involvement of kallikrein hK2 in the hydrolysis of the human seminal vesicle proteins after ejaculation.

We have recently demonstrated in liquefied human seminal plasma the presence of the novel kallikrein hK2 in association with protein C inhibitor (PCI) as a 75-kDa complex. In the present study, we showed that hK2, immediately after ejaculation, was recovered only in its free form but complex formation with PCI occurred rapidly thereafter and was completed within 10 minutes. That reaction required an enzymatically active kallikrein. In order to determine the patterns of hydrolysis of major seminal vesicle proteins, semenogelins and fibronectin were exposed to hK2 and to hK3 (prostate-specific antigen or PSA) and cleavage sequences were identified by N-terminal sequencing. Free hK2 was able to hydrolyze semenogelins and fibronectin in vitro. Most of cleavage sites were at the carboxyl-side of arginyl residues. Semenogelins were hydrolyzed to a similar extent by catalytic (and similar) concentration of either hK2 or PSA though no common cleavage sites was identified for both proteinases. Unlike semenogelins, fibronectin was hydrolyzed much more efficiently by hK2 than by PSA. These results show that hK2 is enzymatically active during a short period of time after ejaculation, that major seminal vesicle proteins can be the target of this proteolytic activity, and that hK2 and PSA have different substrate specificities.

Antibody Specificity↗