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Biomedical subjects

I Chowers

Publications and source records attributed to I Chowers.

At least 73 records · Page 4Linked to original sources
PubMed1980

Effects of systemically administered indomethacin on basal and stress-induced ACTH and corticosterone secretion in the male rat.

The effects of the prostaglandin (PG) synthetase inhibitor indomethacin (IM) on basal and stress-induced activity of the hypothalamo-hypophyseal-adrenal (HHA) axis were investigated. IM was systemically administered to adult male rats in a single injection (5 mg/100 g BW s.c.). The animals were sacrificed 24 h later, either under basal conditions, or following 30 min exposure to environmental temperature of 36 degrees C. Serum ACTH and corticosterone (CS) were determined by RIA and CBG, respectively, and hypothalamic and adenohypophyseal PGE2 and total PGE concentrations were estimated by RIA. IM treatment resulted in elevated basal levels of both hormones. Heat exposure led to elevated serum ACTH and CS concentrations in both vehicle- and IM-treated groups, with the ACTH heat response in IM-treated animals being greater than that observed in controls. PGE2, and PGE1 plus PGE2 concentrations were markedly reduced in both hypothalamic and adenohypophyseal tissues, following IM treatment. This study demonstrates that simultaneous reductions in hypothalamic and adenohypophyseal PG concentrations are compatible with hyperactivity of the HHA axis.

Adrenal Glands↗
PubMed1980

Superiority of bromocriptine over pyridoxine in the treatment of patients with acromegaly or galactorrhea.

Sixteen patients, eight with acromegaly and eight with galactorrhea, were treated with pyridoxine (600 mg/day) for a three-month period. The clinical and biochemical changes induced by the drug were compared with those induced by bromocriptine (2.5 to 50 mg/day) administered for the same length of time to the same patients. Pyridoxine induced lowering of growth hormone and prolactin levels in two acromegalic patients. In only one patient with galactorrhea after irradiation of the hypophysis for active acromegaly did pyridoxine treatment stop and galactorrhea and induce renewal of menstrual bleeding without significantly changing the basal prolactin levels. In another patient with a chromophobe adenoma of the hypophysis, it reduced the excessively elevated prolactin levels. On bromocriptine therapy, all the patients reported signifcant clinical improvement paralleled by significant drops in plasma growth hormone and prolactin. It appears that at the dosages administered bromocriptine is preferable to pyridoxine in the treatment of patients with acromegaly or galactorrhea.

Acromegaly↗
PubMed1979

PRL and ACTH secretion following acute heat exposure, in intact and in hypothalamic deafferentated male rats.

Adult male rats, intact or bearing complete, anterior or posterior hypothalamic deafferentiations (CHD, AHD AND PHD, respectively) were acutely exposed to environmental temperature of 36 degrees C, and serum PRL and ACTH concentrations were determined by RIA. In intact animals, heat exposure resulted in elevated serum PRL and ACTH levels. None of the deafferentations affected basal serum PRL concentrations, whereas those of ACTH were elevated in both CHD and AHD, but not in PHD groups, as compared to intact controls. The PRL heat response was completely absent in CHD, attenuated in AHD, and delayed in PHD animals, and the ACTH heat response was absent in all three groups. These results demonstrate (1) that acute exposure to elevated environmental temperature stimulates secretion of PRL and of ACTH; (2) that this stimulation is carried out by diverse neural pathways; and, (3) that hypothalamic modulation of the secretion of PRL and ACTH is effected by independent mechanisms.

Adrenocorticotropic Hormone↗
PubMed1979

Neuroendocrine function in long-term pinealectomized male rats, following visual and audiogenic stress.

Intact, sham-pinealectomized and pinealectomized adult male rats were maintained for 10 weeks on a light : dark (L : D) cycle of 12 : 12,with lights on at 6 a.m. Subsequently they were acutely exposed to (1) visual or (2) audiogenic stress for periods of 2 or 30 min, immediately following which they were decapitated and serum ACTH, corticosterone, FHS, LH, PRL and TSH concentrations were determined. Serum ACTH and corticosterone levels were similar in control and operated groups following both types of stresses. Serum FSH and LH concentrations were elevated in pinealectomized animals as compared to controls, following 30 min of exposure to visual stimulation; no difference in these parameters was observed between the groups following audiogenic stress. Serum PRL levels tended to be lower in pinealectomized animals following both stresses. Serum TSH concentrations following visual stimulation were similar in all groups, but audiogenic stimulation resulted in elevated TSH levels as compared to controls. These data demonstrate that the pineal gland plays an integral role in the responses of the parvicellular neuroendocrine axes to acute neurogenic stress. Possible molecular bases for this involvement are discussed.

Acoustic Stimulation↗
PubMed1979

TSH secretion following acute heat exposure, in intact and in hypothalamic deafferentated male rats.

Male rats, intact (N) or with complete, anterior, or posterior hypothalamic deafferentations (CHD, AHD, or PHD, respectively), were acutely exposed to an environmental temperature of 36 degrees C, and serum TSH concentrations were determined by RIA. In intact animals, 30 min of exposure to elevated environmental temperature resulted in decreased serum TSH levels. In both CHD and AHD animals, basal serum TSH concentrations were reduced, and heat exposure produced further decreases. In the PHD group, no significant difference in resting serum TSH concentrations was observed, as compared to intacts. Exposure of these animals to 36 degrees C was followed by a reduction in this parameter, similar to that in intact rats. Exposure of intact animals to 3 nonthermal stress modalities produced no changes in serum TSH concentrations. These experiments demonstrate (1) that the hypothalamo-hypophyseal-thyroid axis responds specifically to heat exposure; (2) that extrahypothalamic centers which innervate the medial basal hypothalamus from the rostral direction maintain basal activity of the axis; and (3) that humoral factors, possibly extrahypothalamic thyrotrophin-releasing hormone carried to the median eminence via the CSF, may also mediate both basal and heat-induced secretory activity of the thyrotrophs.

Afferent Pathways↗
PubMed1979

Disseminated echinococcosis with repeated anaphylactic shock. Treated with mebendazole.

A 46-year-old man, who was twice operated on for echinococcosis and who suffered from recurrent angioneurotic edema, was hospitalized with anaphylactic shock. Chest x-ray examination showed round lesions in the lungs; Casoni, immunofluorescence and hemagglutination tests for echinococcosis were strongly positive. With a diagnosis of disseminated echinococcosis, drug treatment with mebenzadole was given for 29 weeks (the last 22 weeks a dose of 1,200 mg daily). No side effects were observed, allergic manifestations disappeared, and the round lesions were noticeably reduced. The titer of hemagglutination fell gradually, and IgE concentration initially increased and later fell. Mebendazole is proposed as a drug of choice in the cure of disseminated hydatidosis; it may both alter the indication for operation and considerably improve the prognosis.

Anaphylaxis↗
PubMed1979

Sensitivity of human spermatozoa to various isolation procedures: differences in relation to sperm counts.

The aim of the present work was to examine the sensitivity of human spermatozoa from oligospermic and normospermic semen samples to manipulations in the course of isolation by generally used procedures. To this end we performed protein and DNA estimations in spermatozoa isolated by procedures differing in rigorousness (washings with Ringer's buffer and a medium containing ficoll) as well as microscopic examinations of washed sediments. The results showed that the washed sediments contained, in addition to spermatozoa, materials containing protein and DNA, possibly deriving from the breakage of sperm cells. These materials increased in amount with the decrease of original sperm counts. We suggest that abnormal spermatozoa, whose percentage usually increases with the severity of oligospermia, are more sensitive to damage than the normal ones.

Buffers↗
PubMed1978

Day-to-day variations in serum levels of follicle-stimulating hormone and luteinizing hormone in homosexual males.

Levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone in sera of eight homosexual males and a matched control group were determined every second day during one month. Significant day-to-day variations in serum levels of FSH and a reversed LH area/FSH area ratio among homosexuals were found. There were no significant differences between homosexuals and controls in relation to the average levels of the tested hormones nor the average area and variance of LH and testosterone. It is suggested that a single blood sample for each subject is not enough for hormonal evaluation of homosexuals. It is suggested that the present findings may point to some defect in the gonadotropin regulation in male homosexuals.

Female↗
PubMed1977

cAMP in temperature- and ADH-regulating centers after thermal stress.

cAMP concentrations in temperature-regulating sites of the brain and plasma osmolality were measured after exposure of male rats to 36 degrees C and 37-42% rh. for 10, 20, or 30 min. Plasma osmolality was affected by none of the heat exposures. In both the preoptic area and the posterior medial hypothalamus, cAMP concentrations were increased compared to controls, after 10, 20 and 30 min of heat exposure. In the supraoptic-paraventricular nuclei, neither 10 nor 20 min of exposure resulted in augmented cAMP concentrations; but after 30 min of heat exposure, cAMP levels in these nuclei were significantly greater than in controls. Neurohypophysial cAMP concentrations were increased after both 10 and 30 min of exposure. Cerebral cortical cAMP concentrations were not affected by thermal stress. It is concluded that cAMP is involved in the neural mechanisms which are brought into play to regulate body temperature during acute heat exposure. The significance of this involvement and its relation to the overall temperature-regulating mechanisms of the body are discussed.

Animals↗
PubMed1977

A case of adrenogenital syndrome with aberrant 11beta-hydroxylation.

A 17 year old female patient with hypertension, amenorrhoea and hirsutism was found to have subnormal levels of plasma and urinary cortisol, significant plasma levels of Reichstein's compound S and 21-deoxycortisol, high urinary levels of THS and pregnanetriolone as well as elevated levels of plasma and urinary testosterone. Treatment with 0.5 mg/day of dexamethasone or 25 mg/day cortisone reduced her hypertension and restored her menstrual cycles, but also resulted in the development of moon face, body striae and a gain in weight. Lower doses of cortisone were without effect. The deficient cortisol production coupled with the presence of unusual intermediates such as Reichstein's compound S and 21-deoxycortisol can be explained by a shift in the substrate specificity of 11beta-hydroxylase from C-21-hydroxylated substrates (i.e. compound S) to C-21-deoxy substrates (i.e. 17-hydroxyprogesterone).

17-Ketosteroids↗
PubMed1976

Body temperature and adrenal function in heat-exposed hypothalamic disconnected rats.

The effects of hypothalamic disconnection on body temperature and hypothalamo-pituitary-adrenal activity following acute and repeated exposures to heat were studied. Intact male rats, or animals with complete posterior or anterior hypothalamic disconnection, were exposed to a temperature of 36 degrees C and a relative humidity of 35-45%. In the complete posterior and anterior hypothalamic disconnected rats the basal Tre was higher than that of the intact rats; the rise in Tre following heat exposure was lower in the operated rats than in the intact animals. All the experimental animals, except for those with anterior hypothalamic disconnection, showed a significant inhibition of corticosterone release on exposure to heat for 30 min, but no inhibition was observed in any of the disconnected rats when they were exposed to heat for 120 min. These results suggest that the main stimulus for ACTH release, during the first 30 min of heat exposure, is mediated by a neural input through the posteroir hypothalamus and this is followed by a nerural and/or humoral mechanism which enables the animals to increase their corticosterone secretion.

Adrenal Glands↗
PubMed1976

Protein content of human seminal plasma and spermatozoa in relation to sperm counts.

Protein concentrations of seminal plasma and spermatozoa were estimated in human normospermic, oligospermic and azoospermic semens. The protein content of seminal plasma ranged from 20 to 60 mg per ml semen and was found to be unrelated to sperm counts. Suspended sediments of azoospermic specimens were found to contain on the average 570+/-86 microng protein per ml semen. This value is about four times higher than in severe oligospermic specimens (0.2 X 10(6) -6.5 X 10(6) cells per ml semen). It is suggested that in azoospermic disorders seminiferous tubules secrete abnormally high amounts of proteinacous material which cannot be eliminated by washings. In addition, destruction of immature cells may contribute to increased protein conten in these specimens. Protein determinations in washed spermatozoa showed a negative relationship between the amount of protein calculated per 10(6) cells and original sperm counts. This trend demonstrates an altered protein metabolism in the spermatozoa of oligospermic specimens which might be responsible for fertility incompetence.

Adult↗