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Biomedical subjects

G Schaison

Publications and source records attributed to G Schaison.

358 records · Page 20Linked to original sources
PubMedDate not supplied

[Study of plasma androstenedione and testosterone levels in hypercorticism syndromes].

Plasma T and A were studied in 10 patients with hypercorticism. In the female patients, plasma A and T were elevated in 4 cases of Cushing's disease, slightly decreased in 2 cases of adrenal adenoma and greatly increased in I case of adrenal carcinoma. In 3 male patients, A plasma levels followed ACTH levels, but T was subnormal, irrespective of the cause of hypercorticism. Furthermore, in 8 normal men, the decrease of plasma T, observed after ACTH administration, was not directly related to ACTH, but rather to cortisol, as it was not observed after metyrapone induced ACTH increase. As no change in LH secretion was shown and as dexamethasone reduced the testosterone response to HCG, it seems likely that glucocorticoids act directly on testosterone biosynthesis.

Adrenal Cortex Neoplasms↗
PubMedDate not supplied

[LHRH in man. Current data].

LHRH physiology is now well known. This decapeptide is released every 60 to 120 minutes by the hypothalamic pulse generator. Dopamine, noradrenaline, prostaglandins and endogenous morphinomimetics play a role in its regulation. Testosterone exerts its feed back exclusively at the hypothalamic level. LHRH action at the pituitary level is mediated through high affinity receptors. LHRH internalization is not necessary for its action which is calcium-dependent. At the testicular level, LHRH receptors are identical to those on the pituitary. Acute administration of LHRH increases both receptors on the pituitary and the testis. The synthesis of LHRH analogs with prolonged effects has produced agonist and antagonist substances which both inhibit gonadotropins. This gonadotrope inhibition is explained, in the case of agonists by both pituitary and gonadal desensitization in animal experiments. This last action is linked to LH increase. In the rat, LHRH has also led to a parallel impairment of steroidogenesis by 17 hydroxylase and 17-20 desmolase deficiency. The physiological effect of LHRH is produced exclusively by pulsatile administration. It can now be considered for the treatment of hypogonadotrophic hypogonadism. Moreover, the gonadotrope inhibition induced by LHRH agonist with prolonged action can be of therapeutic use in idiopathic precocious puberty, prostatic cancer and inhibition of spermatogenesis (an association with androgens being necessary in this last case).

Animals↗
PubMedDate not supplied

[Idiopathic thrombocytopenic purpura (ITP) in childhood (author's transl)].

Half of thrombocytopenic purpuras occurs after a viral infection and is cured in a few weeks, but 10% of the cases are chronic. Toxic purpura is exceptional. Most of the cases are idiopathic. At the beginning it is impossible to foresee acute or chronic evolution. No treatment is necessary in ITP without serious bleeding. Prednisone does not avoid chronic state but shortened duration of acute ITP. Dosage is 1 mg/kg/day. Continuous corticotherapy is excluded in chronic ITP. Short corticotherapy is useful during bleeding periods. Splenectomy is to be considered after 6 or 12 months. Overall success raise 75%. Splenectomy is forbidden temporarily before 5 years, and definitely in immune deficiency. Immunosuppressive drugs are rarely used in childhood. Treatment with infusion of vincristine labeled platelets is in study. During the 18 months after cure, vaccinations must be avoided.

Child↗
PubMedDate not supplied

[A programme for male infertility investigation (author's transl)].

Male infertility investigation must proceed according to a strict order to state precisely the etiology. Among the essential exams, the semen analysis, the post coital test, LH, FSH and testosterone assays are the corner stones of the evaluation of the infertile male. The recent advances were made on the ultrastructure of spermatozoa and its abnormalities (ciliary dyskinesis) and the syndrome of partial resistance to androgens. But the research for a curable form of infertility is too often useless. Hypogonadotropic hypogonadism, which could be treated by human gonadotropins or LHRH, represents only 0,5% of the cases. The results of surgery are rather poor. Sometimes, the improvement of sperm quality by laboratory manipulations permits artificial insemination.

Coitus↗
PubMedDate not supplied

[Normal and pathologic imaging of the pituitary stalk].

Study of the pituitary stalk pathology about six demonstrative cases. This illustrative cases are described after review of literature, anatomy and imaging modalities. CT and MRI are very sensitive technics but not very specific.

Humans↗