Biomedical subjects
Publications and source records attributed to F Raynaud.
The populations of interstitial cells in the testis of three 2-3 month old monkeys and of three 5-6 years old adults (Macaca fascicularis) were analyzed: percentage, mitotic index and labeling index after 3H-thymidine injection. In the young monkey and the adult well differentiated Leydig cells incorporate the precursor as fibroblast-like cells. This demonstrates their ability of renewal.
The spontaneous release of growth hormone (GH) during nocturnal sleep was studied at age 5-19 years in 44 male and 15 female patients with severe growth retardation (-2.1 to -6.5 SD) among whom 43 were prepubertal and 16 pubertal. Comparison with the results of classical stimulation tests with ornithine, arginine and/or insulin showed good agreement in cases of classical hypopituitarism (n = 14) as in patients who seemed to be endocrinologically normal (n = 27). In 18 patients (31%) there was a discrepancy between sleep release and responses of GH to stimulation test: treatment with hGH was available in only 4 of these children and enhanced sharply their growth rate. It is suggested that a large span of intermediary situations exists between normal GH secretion and complete GH deficiency, deserving a controlled therapeutic trial with hGH.
We report the initial results arising from analysis of a prospective computerized study of infantile atopic dermatitis in which, among other factors, the criteria of severity of the dermatitis was considered for the first time. Besides providing informations on the natural history of childhood AD, this study showed that onset of asthma was significantly earlier in children affected with severe AD.
In C57BL/6 mice bearing the 3LL carcinoma and in C3H mice bearing the McC3 -1 fibrosarcoma (18th passage), the increase in skin histamine levels was correlated with the increase in mast cell number. The number of cells able to incorporate tritiated thymidine was proportional to the mast cell number. These results strengthen the notion that, in tumour-bearing rodents, the increase in tissue histamine is an active phenomenon.
Explore the source record for details and available documents.
Hamster spermatozoa, collected from the caput and the cauda of the epididymis, are known to differ in their motility. They do not normally acquire fertilizing ability until they reach the proximal portion of the cauda epididymidis. The aim of the present investigation was to test the fertilizing capacity of spermatozoa from the caput epididymis after initiation. Sperm cells were incubated by adding 10 mM caffeine and 20-30 p. 100 epididymal plasma to the culture medium. Superovulated females were inseminated in utero and the eggs recovered 14 h after ovulation. In these conditions, 22 p. 100 of the ova were fertilized. The possibility that the increased motility of the caput epididymal spermatozoa might reflect an increase in fertilizing ability is discussed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The pineal gland is known to synthesize numerous indolamines. Since delta-sleep-inducing peptide (DSIP, a tryptophan nonapeptide) is found in the pineal gland, its effect on the secretion of indolamines was investigated. DSIP stimulated melatonin (MEL), 5-methoxytryptophol (5-ML) and serotonin (5-HT) synthesis and release, whereas it did not affect pineal cyclic AMP levels. The stimulatory effect of DSIP on MEL secretion was dose dependent between 5 x 10(-6) and 10(-4) M, whereas the minimal effective concentration of DSIP on 5-ML secretion was higher than 10(-5) M. The effect of DSIP (10(-4) M) was compared to the effect of isoproterenol (ISO, 10(-6) M) on MEL and 5-HT release. ISO stimulated MEL secretion and concomitantly decreased 5-HT release. With regard to kinetic characteristics, the effect of DSIP (10(-4) M) on MEL release was faster and of shorter duration than the effect of ISO (10(-6) M; 2 and 4 h, respectively). At 10(-4) M, DSIP potentiated the ISO-induced increase of MEL secretion. The DSIP-stimulated release of MEL was not significantly altered when the pineal glands were treated with 10(-5) M propranolol (a beta-adrenergic antagonist), 10(-5) M prazosin (an alpha 1-adrenergic antagonist) or 10(-5) M naloxone (an opioidergic antagonist). This study demonstrates that the DSIP-induced secretion of indolamines from rat pineal glands may not be elicited through the well-known noradrenergic or opioid systems.
Pharmacokinetic studies of exogenous melatonin (100 or 1 micrograms) administered to 5-methoxypsoralen (MOP)-treated rats, showed that MOP administration induced an increase in the half-life of melatonin from 22 to 67 min. This delayed degradation of melatonin was the consequence of 5-MOP-induced inhibition of the 6-hydroxylation of melatonin. Under in vitro experimental conditions, 5-MOP did not affect melatonin synthesis and release. These results demonstrate that the elevated plasma melatonin concentrations observed in vivo following 5-MOP administration is due to inhibition of the hydroxylation of endogenous melatonin.
Two normal boys, with no previous history, were referred at the onset of puberty for unilateral testicular hypertrophy. Radiological and biological investigations, and in one case testicular biopsy, ruled out cellular proliferation or tumor. Except for FSH level slightly above normal in one case, no endocrine abnormality was found. This is a rare, and probably non pathologic event.
A specific, sensitive and reproducible high-performance liquid chromatographic (HPLC) method is described for the simultaneous measurement of 6-hydroxymelatonin and melatonin in rat plasma. Using this technique, a dose-dependent increase in 6-hydroxymelatonin concentration was observed 10 min after administration of different doses of melatonin. Plasma 6-hydroxymelatonin represented 1% of plasma melatonin, irrespective of the melatonin dose administered. After administration of 100 micrograms melatonin, 6-hydroxymelatonin could be detected in plasma from 7.5 to 60 min. In the same experiment, plasma 6-sulfatoxymelatonin concentrations determined by radioimmunoassay could be detected from 7.5 to 120 min. This HPLC technique allows the measurement of 6-hydroxymelatonin together with melatonin. Combined with an RIA for 6-sulfatoxymelatonin, it could be useful in determining the site of action of drugs affecting melatonin metabolism.