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Biomedical subjects

S Feldman

Publications and source records attributed to S Feldman.

At least 325 records · Page 18Linked to original sources
PubMed1980

Participation of the dorsal hippocampus in the glucocorticoid feedback effect on adrenocortical activity.

The feedback effect of systemically administered dexamethasone on basal plasma corticosterone levels and on adrenocortical responses to ether plus skin incision stress were studied in intact rats and in animals with bilateral dorsal or ventral hippocampectomy or fimbria section. It was found that in rats with ventral hippocampectomy or fimbria section, the degree of the feedback was similar to that in intact rats. However, in animals with dorsal hippocampectomy, the inhibitory effect of dexamethasone on basal and stress-induced adrenocortical responses was significantly reduced. These results taken together with previous observations, that section of the dorsal fornix has a similar effect, suggest that dexamethasone exerts its influence on the brain and that the dorsal hippocampal formation participates in the feedback regulation of pituitary-adrenal function. It cannot be excluded, however, that dexamethasone may exert its influence on the pituitary, and the effect observed may be summation of dexamethasone action on the pituitary plus lack of hippocampal input.

Adrenal Cortex↗
PubMed1980

Adrenocortical responses in dexamethasone-treated rats with septal, preoptic and combined hypothalamic lesions.

To elucidate the role of limbic structures in the negative feedback regulation of corticoids of adrenocortical function, the effect of dexamethasone on adrenocortical responses to ether stress was studied in intact and lesioned rats. In animals with septal and preoptic lesions the degree of the feedback of dexamethasone on adrenocortical responses was similar to that in intact rats. In animals with bilateral medial forebrain bundle lesions the feedback influence was enhanced, but this was reversed by a subsequent posterior hypothalamic deafferentation, which if produced separately diminished the feedback effect. This would indicate that though the septum and preoptic area do not play a significant role in the feedback of dexamethasone, there is a mutual interaction between closely situated facilitatory and inhibitory systems in the feedback control of adrenal function.

Adrenal Cortex↗
PubMed1980

Delayed response to a alpha-hydroxycholecalciferol therapy in a case of hypoparathyroidism during anticonvulsant therapy.

A patient with idiopathic hypoparathyroidism and a six-year history of a convulsive disorder was treated with 1 alpha-hydroxycholecalciferol and anticonvulsants. The calcemic response to 1 alpha-hydroxycholecalciferol was incomplete. However, normocalcemia was later attained during treatment with dihydrotachysterol. This delayed response suggests that the anticonvulsant therapy interfered with the peripheral effect of the vitamin D metabolite.

Adolescent↗
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

Salmonellosis in children with cancer: review of 42 cases.

Forty-two episodes of culture-proved salmonellosis were found retrospectively among 2,262 patients treated for malignant diseases at St Jude Children's Research Hospital, Memphis. These cases were reviewed in an effort to determine whether Salmonella infections in childhood cancer patients are associated with an increased frequency of septicemia and death, as has been reported for adults with cancer. Septicemia occurred in only 10% of the patients studied, consistent with the frequency established in general populations. There were no deaths attributable to Salmonella infection. Most of the patients (57%) with salmonellosis had gastroenteritis, and the clinical course of this syndrome was no more severe or prolonged than that seen in otherwise normal children. We recommend that management of Salmonella infections in children with cancer follow presently accepted guidelines for normal hosts.

Adolescent↗
PubMed1979

Toxicity of amphotericin b in children with cancer.

The pattern of amphotericin B toxicity was assessed retrospectively in a group of 20 children with cancer who had received one or more courses of the drug for treatment of systemic fungal infection. Azotemia was the most frequent complication, developing during 23 of 24 treatment courses. Other major toxic effects, in decreasing order of frequency, were anemia, hypokalemia, thrombocytopenia, and neutropenia. Infusion side effects, including drug-related fever, chills, and nausea, were also frequently seen. Seventeen of 20 patients were treated for disseminated histoplasmosis. Nineteen of 20 patients had acute leukemia. Although interaction with other agents could not be excluded, amphotericin B appeared to be the major causative agent for the toxic reactions noted. In no patient, however, was administration of amphotericin B stopped because of drug toxicity.

Adolescent↗
PubMed1979

Effect of enzyme-inducing and enzyme-inhibiting agents on drug absorption. II. Influence in proadifen on 3-O-methylglucose transport in rats.

Studies utilizing the in vitro everted rat jejunum were performed to investigate the effects of proadifen pretreatment and fasting on active and passive intestinal transfer of 3-O-methylglucose. Animals were pretreated 24 hr prior to the experiments with 100 mg of proadifen/kg ip. With mucosal concentrations of 0.1 mM 3-O-methylglucose and 14C-3-O-methylglucose, transfer to the sugar-free serosal buffer after pretreatment with proadifen was 50% greater than controls after a 24-hr fast and 120% greater than controls after a 48-hr fast. Everted intestinal segments obtained from unfasted control animals showed diminished ability to transfer the sugar derivative, with transfer rates approximately 50% less than those of segments obtained from 24-hr fasted control animals. Wet and dry tissue weights for 24- and 48 hr-fasted groups increased following proadifen pretreatment. The results suggest that proadifen enhances 3-O-methylglucose transport across the rat jejunum and also increases intestinal tissue weight.

Animals↗
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↗