Search PubMed⌕ Search

Biomedical subjects

J M Davidson

Publications and source records attributed to J M Davidson.

At least 235 records · Page 13Linked to original sources
PubMed1967

Antiandrogen implanted in brain stimulates male reproductive system.

Chronic intrahypothalanic implantation of cyproterone, an antiandrogen, in male rats resulted in specific stimulation of testes, seminal vesicles, and prostates. Implantation of cholesterol-filled or empty tubes in the median eminence in controls was ineffective. We conclude that decreases in the amount of testosterone reaching specific receptors in the median eminence or in nearby regions activate a mechanism that produces increased gonadotropin secretion.

Adrenal Glands↗
PubMedDate not supplied

Gastroschisis and omphalocele: prenatal diagnosis and perinatal management.

Obstetric ultrasonography has made the prenatal diagnosis of gastroschisis and omphalocele more common. We present illustrative cases and review the ultrasonographic features. Because of the increased risk of concomitant abnormalities (including trisomies) with omphalocele, full evaluation is indicated when this diagnosis is suspected. Recent perinatal approaches to delivery have favoured caesarean section, without scientific evidence that outcome is improved. Our experience, as well as a review of the literature, suggests that the outcome for vaginally delivered infants is acceptable. A prospective study of this question is needed.

Adolescent↗
PubMedDate not supplied

The inhibition of sexual behavior in male rats by propranolol is stereoselective.

We have previously reported that administration of racemic mixtures of propranolol was associated with a marked inhibition of mating behavior in male rats. To compare the effects of (+)-propranolol, (-)-propranolol, and (+/-)-propranolol in sexually experienced males, rats ejaculating in four or more mating tests were divided into three groups (N = 16 per group) such that no differences in parameters of copulatory behavior were evidence in preexperimental tests. No major effect of propranolol on parameters of behavior associated with initiation of sexual behavior was evident. In contrast, other measures of behavior were profoundly modified. The ejaculatory threshold, indicated by the number of intromissions preceding ejaculation, was increased after (+)- and (+/-)-propranolol, but not (-)-propranolol. The number of mounts without intromission preceding ejaculation was increased only after (+/-)-propranolol. A decrease in copulatory efficacy was evident after (-)- or (+/-)-propranolol, but not after (+)-propranolol. Increases in ejaculation latency, intercopulatory interval, and postejaculatory interval were observed after (-)- and (+/-)-propranolol, but not after (+)-propranolol. In summary, the present data indicate that the (-) isomer of propranolol is the active form necessary for the inhibitory effects of propranolol on male sexual function. We suggest that this inhibition is due to specific receptor-mediated mechanisms, involving beta-adrenoceptors and 5-HT1A receptor interactions.

Animals↗
PubMedDate not supplied

Wound repair.

Explore the source record for details and available documents.

Extracellular Matrix↗