Biomedical subjects
Publications and source records attributed to A Demoulin.
We have studied the effects of ultrasound on the female rat fertility. When utilized at similar power than for human beings, the echography reduces significantly the number of foetus counted at the 15th day of the gestation. A direct action of the ultrasounds on the mechanisms of the ovulation is to be considered.
Intramuscularly administered HMG in women induces an increase of serum FSH after 2 hours. Maximal values are reached between the 6 th and the 24 th hour and remain statistically increased until the 48 th hour. An important individual variability is however observed. The modifications of serum LH are inconstant.
Meiotic chromosomes of adult mice testes cultured in vitro have been studied. All meiotic stages are present and normal until the 8th day; suitable figures for chromosome studies may be obtained with routine cytogenetic methods. During the 9th and 10th day in vitro, the number of cells in meiotic progress falls abruptly. By the 14th day, only a few pachytene stages are still observed. This breakdown of meiosis, linked with the disappearance of the germ cell line, is not due to chromosome anomalies that could have arisen in the new environment. Labeling with tritiated thymidine suggests that spermatogonia do not enter meiotic division in vitro. Chromosomes observed with this technique belong to cells already involved in meiotic processes at time of the initiation of the culture.
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Conjugated urinary catecholamines are increased during normal human pregnancy. The modification in the proportions of conjugated fractions are particularly significant for norepinephrine. They depend on the foetoplacental unit since delivery is followed by a reduction of the urinary concentrations of these conjugated fractions. Such a modification of catecholamine metabolism must be kept in mind when the level of sympathetic nervous system activity is studied during pregnancy.
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Peritoneal fluid formation and composition is under the dependence of the ovarian function. Collection of these fluids was performed by laparoscopy in normal cycling women. After absorption of the steroids, they were tested on monolayer pituitary cell cultures in order to study the influence on gonadotrophin release. LH secretion was stimulated through cell the menstrual cycle without any cycling variations. FSH secretion was also increased, excepted in the immediate post-ovulation period. Thus the Peritoneal fluid contains, as follicular fluid, substances with gonadocrinin- and inhibin-like activity. Gonadocrinin activity was not correlated with estradiol and progesterone levels in serum and peritoneal fluid.
Three preparations of inhibin extracted from ram rete testis fluid (RTF) and from human seminal plasma (HSP) reduce tritiated thymidine incorporation into testicular desoxyribonucleic acids (DNA) in vitro. Effect of low molecular inhibin from RTF is dose-dependent. Castrated ram serum does not modify testicular DNA synthesis in vitro. Besides their suppressive action on follicle stimulating hormone (FSH) secretion in vivo and in vitro, these inhibin preparation display a direct inhibiting effect on testicular DNA synthesis and, thus, on mitotic activity. Identity between inhibin and testicular chalones are discussed.
In vivo, Enkephalins, stimulate PRL, inhibit LH and are inactive on FSH. However, in monolayer pituitary cell cultures, PRL, LH and FSH secretions and synthesis are not modified by Met-Enk. (5 microgram/ml) or Leu-Enk. (5 and 10 microgram/ml). But the simultaneous presence of LHRH and Enk. induces an increase in LH secretion and synthesis without modifying FSH and PRL. In conclusion 1) Enk do not act by themself at the pituitary level but 2) they are able to modify the responses induced by hypothalamic hormones.
Urinary elimination of conjugated catecholamines (adrenaline and noradrenaline) is increased during normal pregnancy (60.5 % in the normal ; 70 % in the pregnants).
The alveolar macrophage belongs to the "Mononuclear Phagocytic System". The medullary promonocyte is its stem-cell. It has a kidneyshaped nucleus, a developed vesicular Golgi apparatus, numerous mitochondriae, lysosomes, phagosomes, and a rough or smooth ergastoplasm. It can survive several weeks in vitro, when cultivated on a porous membrane in contact with a nutrient medium and incubated in a gaseous phase (5 per cent carbon dioxide in water saturated air). Mitotic activity is questionable. Oxygen consumption is high during endocytosis. Metabolic energy is derived from direct oxidative glucose breakdown. Its anti-infectious property is based on phagocytosis as well as on cytoplasmic germicidal or lytic systems (hydrogen peroxide, catalase, free oxygen radicals, hydrogen ion, lysozyme and other lysosomial hydrolases). This function is stimulated by T lymphocyte and by endocytosis of digestible material. In vitro, the alveolar macrophage is capable of inhibiting intra-cellular development of Candida albicans, Klebsiella pneumoniae, Listeria monocytogenes, Staphlylococcus albus and Staphylococcus aureus.
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Mouse testes were cultured for 19--20 days at either 31 or 37 degrees C with a change of medium every 4 days. After treatment with charcoal and dextran T, the recovered testis media were incubated with rat anterior pituitary cells, and secretions of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were estimated by radioimmunoassay 3 days later. FSH release was significantly lowered when pituitary cells were grown with media of testes cultured 31 degrees C compared to cultures grown with fresh medium or with media of testes cultured at 37 degrees C for more than 4 days. LH secretion was normal in one experiment and reduced in the other with the media of testes cultured at 31 degrees C. Treatment of testicular media by heat or trypsin reduced the inhibiting activity. After 8 days at 37 degrees C, both germinal and Sertoli cells were damaged in the testis cultures, while at 31 degrees germinal cells alone were destroyed, Sertoli cells remained normal. These studies suggest that (1) a substance which responds to the definition of inhibition (protein--preferentially acting on FSH) is secreted in the medium of testis culture; (2) inhibin is produced by Sertoli cells; (3) inhibin is secreted only if the temperature is inferior to 37 degrees C.
tritiated thymidine is incorporated into DNA of spermatogonia type B as proved by autohistoradiography when injected in vivo three hours before the sacrifice. Maximum binding and specific activity (labelled thymidine expressed in DPM per mg DNA) are obtained in pubertal rats aged 42 days and weighting 150 g. Inhibin preparation extracted from rete testis fluid (RTF3) specifically inhibits tritiated thymidine into testicular DNA. Thus, no modification of incorporation into hepatic DNA is observed and the preparation loses its inhibitory effect when denatured by heating and trypsin digestion. Tritiated thymidine incorporation into testicular DNA is poor in normal adult rats and in pubertal hypophysectomized animals, RTF3 does not modify the thymidine incorporation in both conditions. The reasons for this lack of effect are discussed. An experimental condition of spermatogonial regeneration is obtained by testicular irradiation. Inhibin preparation inhibits the regenerative DNA synthesis.
Human seminal plasma obtained by centrifugation of human semen contains a factor capable of selectively inhibiting the secretion of FSH both in vivo (reduction of the levels of FSH in rats 24 h after castration) and in vitro (reduction of the FSH released by LH-RH in rat pituitary cell culture). This effect is not due to testosterone, oestradiol-17 beta or progesterone present in the active fractions. The factor has the characteristics of a protein in that its biological activity is destroyed by heat and trypsin digestion. It does not resemble androgen-binding protein. The biological action is not completely specific for FSH as inhibition of LH can be seen with doses usually higher than those which produce inhibition of FSH alone. There is no effect on TSH or prolactin levels in vitro. The factor clearly acts on the release and synthesis of gonadotrophins by gonadotrophs but an effect on the hypothalamus is not excluded. This factor fits the definition of inhibin.
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