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Biomedical subjects

N Altman

Publications and source records attributed to N Altman.

32 records · Page 2Linked to original sources
PubMed1976

Neuroendocrine studies of depressive illness.

Interest in possible neuroendocrine disturbances in endogenous depression is prompted by two lines of evidence: (1) clinical features of the illness suggest hypothalamic dysfunction; (2) the brain neurotransmitters implicated in depression also regulate neuroendocrine function. Our research reveals a marked, sustained hypersecretion in cortisol in severe depressive illness, which is apparently unrelated to stress and sleep disturbance, and which is associated with a distortion of the 24-hour cortisol secretory pattern. The hypersecretion is manifested primarily in the late afternoon, evening, and early morning hours, when cortisol secretion is normally inhibited. Growth hormone responses to hypoglycemia (but not to L-dopa) are also significantly reduced in endogenous depression, even when factors of age and the menopause are controlled. Postmenopausal depressed women appear to secret significantly less LH than normal postmenopausal women. Since all of these hormonal abnormalities can be reproduced by depletion of brain noradrenalin, the findings provide support for the the hypothesis of reduced functional noradrenergic activity in certain forms of depression.

Aged↗
PubMed1975

Growth hormone responses to hypoglycemia in postmenopausal depressed women.

Human growth hormone (HGH) responses to insulin-induced hypoglycemia were measured in ten postmenopausal women suffering from primary unipolar depressive illness, and in ten age-matched normal postmenopausal women. The mean maximal HGH response in the depressed patients was 4.6 plus or minus 4.4 ng/ml, and in the normals 13.3 plus or minus 9.8 ng/ml (P less than .05). All of the normal subjects had clinically adequate HGH responses, in contrast to only four of the depressed patients (P less than .01). The blood glucose responses were virtually the same in the two groups. Since brain catecholamines play a major role in mediating HGH responses to hypoglycemia, the findings are consistent with the hypothesis of diminished functional catecholaminergic activity in the depressed patients.

Aged↗
PubMed1975

Human growth hormone response to levodopa. Relation to menopause, depression, and plasma dopa concentration.

After ingestion of 500 mg of levodopa, postmenopausal women had significantly diminished human growth hormone (HGH) responses (mean, 4.6 ng/ml), as compared with those of age-matched men (mean, 9.1 ng/ml; P smaller than .05). The differences between the groups were not related to plasma dopa concentrations. The HGH responses to levodopa of age-matched unipolar and bipolar depressed men, and of unipolar depressed postmenopausal women, did not differ significantly from their respective normal control groups. Depressive illness of these types does not appear to affect the HGH response to levodopa, once the effect of the menopause is taken into account.

Adult↗
PubMed1975

Thioridazine stimulates prolactin secretion in man.

Thioridazine, unlike most other effective antipsychotic drugs, appears to be only a weak dopamine antagonist in various regions of the brain. We decided to test, indirectly, thioridazine's effects on another brain dopaminergic system, the tuberoinfundibular tract, which regulates prolactin secretion by stimulating hypothalamic secretion of prolactin-inhibiting factor. Chlorpromazine and several other phenothiazines have been shown to stimulate prolactin secretion. Five healthy men ingested 50 mg of chlorpromazine concentrate on one occasion, and 50 mg of thioridazine concentrate on another. Both drugs noticeably stimulated prolactin secretion within two hours. It is concluded that thioridazine is a potent dopamine antagonist in the tuberoinfundibular system, and it is suggested that this system's regulation of prolactin secretion may provide a useful method for studying antipsychotic drug effects in man.

Administration, Oral↗
PubMedDate not supplied

Reduced plasma LH concentration in postmenopausal depressed women.

Mean plasma LH concentration in postmenopausal women suffering unipolar depressive illness was 33% less than that of normal postmenopausal women (P less than 0.05). Since LH secretion after menopause is probably noradrenergically regulated, the finding provides support for the hypothesis of a functional noradrenaline deficit in depression.

Aged↗
PubMedDate not supplied

Inhibition of hamster tongue carcinogenesis by selenium and retinoic acid.

The inhibitory effect of selenium, 13-cis-retinoic acid, and their combination was studied in an animal model in which squamous cell carcinoma of the tongue was induced by 0.5% 9,10 dimethyl-1,2 benzanthracene (DMBA). A controlled, blinded experiment was carried out using 60 Syrian hamsters divided into four groups of 15 each. When compared to controls, the mean day of carcinoma onset was delayed 3 weeks for animals given selenium, 6 weeks for animals given retinoic acid, and 5.5 weeks for animals given selenium plus retinoic acid. The differences between each experimental group and the control group are statistically significant. We conclude that both selenium and retinoic acid inhibit the development of DMBA-induced squamous cell carcinoma of the tongue in hamsters. The dose of retinoic acid used produces a stronger inhibitory effect, but is associated with significant toxicity. At the doses used, combined inhibitory effect is no greater than that for retinoic acid alone.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

Thymic atrophy induced by murine mammary adenocarcinoma in vivo.

The thymic compartment of mammary tumor bearing mice is severely affected with increasing tumor growth. T cell functions in peripheral organs are greatly impaired or absent in such animals. A study of the thymus in relation to tumorigenesis revealed a profound decrease in size accompanied by a disrupture of the normal thymic architecture. Although a strong splenic suppressor cell activity can be detected in this animal model, splenectomy did not prevent thymic involution. Injection of tumor associated factors into normal mice resulted in a thymic atrophy similar to that seen in tumor bearing mice. These findings indicate that the observed thymic involution may not be only due to stress-related phenomena but also a direct effect of the tumor.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

Radiologic characteristics of primitive neuroectodermal tumors in children.

Radiographic findings are reviewed in 31 children with primitive neural ectodermal tumors seen at the Hospital for Sick Children from 1962 through 1983. Seventeen children were initially evaluated with computed tomography (CT). Ten of these had both CT studies and angiography. The tumors were large, irregular, typically iso- to hyperdense, and showed dense, heterogeneous contrast enhancement. Cysts were present in 65% and calcifications in 71% of cases. The angiographic findings were nonspecific, ranging from avascular to markedly vascular. Although these tumors were usually found in the cerebral hemisphere, particularly the frontal lobes, two cases are included of tumors arising elsewhere: one in the pineal and one in the suprasellar region. Epidemiologic data are reviewed.

Adolescent↗
PubMedDate not supplied

Evaluation of the infant spine by direct sagittal computed tomography.

Direct sagittal computed tomography (CT) and metrizamide myelography, in addition to standard axial CT, have proven most useful in evaluation of complex anomalies of the infant spine. Direct sagittal CT was performed by placing the entire infant sideways and supine within the gantry after metrizamide was injected. This technique was performed in six infants with diagnoses of lipoma with dysraphism, lipomyelomeningocele, lipomyelocystocele, lumbosacral agenesis with cord regression, capillary hemangioma, and vertebral osteomyelitis. The technique showed the relation and/or extension of lesions in the dorsal ventral plane, particularly the presence or absence of subarachnoid, enteric, or genitourinary communication. Spinal and paraspinal anatomic detail was also demonstrated beautifully.

Hemangioma↗