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Biomedical subjects

N Altman

Publications and source records attributed to N Altman.

At least 19 recordsLinked to original sources
PubMed1992

Magnetic resonance applications in cerebral injury.

CT and MR imaging are complementary in the evaluation of cerebral head trauma. CT is still more useful for the initial evaluation of the acutely unstable patient who has a head injury. However, many lesions are identified by MR imaging such as cortical contusions, small subdural hematomas, and diffuse axonal injuries that may not be seen on CT examinations. In addition, MR angiography can play an important role in the diagnostic evaluation of the trauma patient. MR angiography can be clinically useful in delineating vascular abnormalities such as arterial occlusions, arteriovenous fistulae, dissecting aneurysms, and venous sinus occlusion. In pediatric trauma, MR imaging appears to be superior to CT in assessing head injuries, particularly those due to child abuse.

Adult↗
PubMed1991

Meningioangiomatosis: clinical, radiologic, and histopathologic correlation.

Meningioangiomatosis (MA) is a rare, benign, hamartomatous lesion of the leptomeninges; MA has been considered to be a forme fruste of neurofibromatosis. A review of pathology records for patients with MA who were seen between 1970 and 1989 at the authors' institutions revealed four patients (three male and one female; aged 2.5-21.0 years; mean, 10.8 years) with a history of seizures but without the stigmata or family history of neurofibromatosis. Three patients had undergone either computed tomographic (CT) or magnetic resonance (MR) imaging studies. All patients had undergone craniotomies to obtain tissue for pathologic analysis; a peripheral, leptomeningeal lesion was found in all four patients. At CT in two patients, the lesions were most consistent with calcification. At T2-weighted MR imaging in one patient, the lesion demonstrated a hyperintense periphery with associated edema of the white matter. Histopathologic examination demonstrated characteristic features of MA--cortical meningovascular fibroblastic proliferation and leptomeningeal calcification. The accurate diagnosis of MA is important since MA is a benign, surgically correctable cause of seizures.

Adolescent↗
PubMed1985

Selenium inhibition of chemical carcinogenesis in the upper aerodigestive tract of hamsters.

Evidence suggests that ingestion of selenium compounds may inhibit carcinogenesis. We studied this in hamsters in which squamous cell carcinoma of the tongue was induced with 0.5% dimethylbenzanthracene (DMBA). Forty-five hamsters, divided into three groups of 15 each, were fed a low-selenium diet and the left lateral border of the tongue was painted with DMBA three times a week. Control animals were given deionized water, while water for animals in groups 1 and 2 contained 3 and 6 ppm selenium, respectively. All sufficiently long-lived animals developed leukoplakia of the tongue and floor of the mouth that progressed to dysplasia and papillary or ulcerative carcinoma. Carcinomas were seen less frequently on the palate and in the pyriform sinuses. Carcinoma metastasized to neck lymph nodes in two hamsters. Data indicate a 2-week delay in leukoplakia incidence for the selenium groups; a higher survival rate was also noted, although this was not statistically significant. We conclude that this model is similar to tobacco-induced squamous cell carcinoma of the upper aerodigestive tract in humans and that ingestion of supplemental selenium produces a modest inhibitory effect on leukoplakia.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1985

Evolution of acute hepatitis B in homosexual men to chronic hepatitis B. Prospective study of placebo recipients in a hepatitis B vaccine trial.

To determine whether the frequency of chronic hepatitis B in homosexual men reflects the high rate of acute hepatitis B or an altered response to hepatitis B, 236 homosexual men were prospectively followed up after entry into the placebo group of a hepatitis B vaccine trial. Sixty-six participants (28.0%) developed hepatitis B ten to 18 months after entering the study. Only four (6.1%) of the 66 had persistence of hepatitis B beyond six months, similar to reports in nonhomosexual subjects. This study suggests that the high rate of acute hepatitis B is the major factor contributing to the high prevalence of chronic hepatitis B in homosexual men, rather than an altered host response. Clinical features of the acute illness could not be used to identify patients who developed chronic hepatitis B.

Acute Disease↗
PubMed1979

A spontaneous outbreak of polycholorinated biphenyl (PCB) toxicity in rhesus monkeys (Macaca mulatta): toxicopathology.

Polychlorinated biphenyls (PCBs) were shown to be the cause of a wasting syndrome and reproductive dysfunction in a group of rhesus monkeys (Macaca mulatta). The polychlorinated biphenyls were found by gas chromatographic analysis in high amounts in the superficial layers of concrete slab floors in the housing facility. The concrete sealant was suspected as the original source although it is not known whether it contained polychlorinated biphenyls before it was applied or if it was contaminated later. Histopathologic findings for the most part were confined to epithelial tissues where squamous metaplasia of several glandular tissues was observed. A striking finding was severe hypertrophy of the glandular stomach and a similar but less severe lesion in the colon. The lesions may be related in part to impaired vitamin A metabolism, but not to a dietary deficiency.

Animals↗
PubMed1978

Prolactin responses to neuroleptics in normal and schizophrenic subjects.

The prolactin response to neuroleptics can serve as an index of dopamine blockade in humans. Plasma prolactin increments to single doses of chlorpromazine, and prolactin decrements to single doses of levodopa, were similar in normal and schizophrenic subjects. Antischizophrenic drugs of all chemical classes stimulated prolactin release,while chemically related drugs and other psychotropic agents ineffective in schizophrenia did not. The prolactin response to neuroleptic therapy occurred in all patients, and tolerance did not develop. Within subjects, prolactin responses were graded according to neuroleptic dose, but the upper limit of sensitivity of the response curve was achieved at doses below the therapeutic range. Relative prolactin-stimulating potency in humans of chlorpromazine, thioridazine, trifluoperazine, butaperazine, and haloperidol correlated well with their relative clinical potencies.

Chlorpromazine↗
PubMed1978

Relation of plasma prolactin to clinical response in schizophrenic patients.

It has been suggested that, if dopamine antagonism is a necessary condition for the antischizophrenic action of neuroleptics, the prolactin response, as an index of dopamine blockade, would correlate with clinical response. Morning prolactin and clinical symptomatology were measured in 15 schizophrenic patients before neuroleptic therapy, and after three and six weeks of high-dose butaperazine or loxapine treatment. Prolactin levels were transiently elevated during the unmedicated admission period, probably reflecting a normal stress response. Prolactin increased in all patients during neuroleptic therapy. There was, however, no correlation between magnitude of prolactin changes and clinical response, probably because the prolactin response achieved a maximum at relatively low doses of neuroleptics.

Adult↗
PubMed1978

Helping the hypochondriac.

Hypochondriasis can be reliably identified and requires a particular therapeutic approach by the family physician. These difficult patients are usually women over 40 with a chronic history of medical work-ups without significant findings, pride in suffering and self-sacrifice and a conviction of being ill which is essential for their self-esteem. To dismiss or confront this conviction results in a drain on medical services, while a supportive approach benefits both physician and patient.

Depression↗
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↗