Biomedical subjects

T Early

Publications and source records attributed to T Early.

5 recordsLinked to original sources

PubMed1999

Neuroleptic influences on a lateralized behavioral bias in unoperated rats.

RATIONALE: Abnormalities of the ascending dopaminergic system have been associated with hemineglect, and evidence suggests that neuroleptic treatments normalize the right hemispatial attentional impairment that is sometimes observed in acutely psychotic schizophrenic patients. OBJECTIVE: A research program was initiated to develop an animal model of hemineglect-drug interactions. METHODS: Female rats were tested repeatedly on removing a "nuisance stimulus" - strips of surgical tape applied loosely to the forelimbs. Subjects were assigned to groups dependent upon showing a behavioral orientation preference (BOP) during pre-drug baseline tests. Animals representing left-BOP, right-BOP and no preference continued to be tested during chronic exposure either to a dopamine antagonist (0.05 mg haloperidol/kg) or agonist (1.0 mg d-amphetamine/kg) or vehicle only. RESULTS: Three weeks of haloperidol treatments to rats only with an initial right BOP gradually eliminated the response bias, as revealed by declines in choosing the right forepaw and the latencies between attending to the two forepaws. CONCLUSION: The results recommend right BOP female rats as a simple, non-invasive behavioral animal model for evaluating and comparing neuroleptic medications.

Amphetamine↗

PubMed1999

Malignant catatonia-induced respiratory failure with response to ECT.

A 47-year-old acutely psychotic schizophrenic man was diagnosed with malignant catatonia. Because of a history of neuroleptic malignant syndrome (NMS), traditional neuroleptics were avoided, and the patient had been treated with reserpine for a period of 10 years. Symptomatically, severe agitation alternated with severe retardation. The syndrome progressed, despite early termination of any neuroleptic medications, to marked catatonic rigidity and dehydration. Worsening was associated with transfer to a medical intensive care unit, intubation, and subsequently a tracheostomy. Dantrolene and bromocriptine were unhelpful. Lorazepam produced muscular relaxation and resulting decreases in creatine phosphokinase levels but elicited no other improvement. Eleven bilateral electroconvulsive treatments, however, resolved the respiratory impairment and catatonia and improved the psychosis. This report highlights the efficacy of ECT in lethal catatonia despite respiratory impairment and tracheostomy.

Catatonia↗

PubMed1996

Male reproductive systems under chronic fluoxetine or trimipramine treatment.

Adult male Long-Evans rats (n = 9 per group) received daily exposure for 4 weeks to fluoxetine (0.75 mg FLUOX/kg body weight) or trimipramine (1.6 mg TRIMI/kg body weight). Separate tests of copulation, sexual motivation, and intermale aggressive behaviors were used to evaluate functional changes during chronic exposure to either typical or atypical antidepressant drugs with more or less serotonin specificity. Circulating hormones, primary and secondary sex structures, and concentrations of dopamine (DA) and serotonin (5-HT) from mesolimbic tissue were assessed at necropsy. Results of tests with estrous females and untreated males revealed progressive disruption to sexual performance and aggressive responsiveness over time of treatment with TRIMI and, to a lesser extent, with FLUOX. By contrast, motivation, testosterone, and all measures of reproductive physiology were indistinguishable from controls. Ratios of transmitter metabolites relative to the parent compounds indicated similar reductions of 5-HT turnover with FLUOX and TRIMI. However, influences on DA turnover were significantly less with FLUOX than with TRIMI. Conclusions are that long-term intervention with antidepressant drugs may disrupt sociosexual exchanges without compromising male rats' interest in sexual contact or integrity of their reproductive physiology. Lessened disruption of sociosexual behaviors with this regimen of chronic FLUOX treatment may be related to the greater selectivity on serotonin relative to dopamine turnover.

Adrenal Cortex Hormones↗

PubMed1992

A validation of a physical activity monitor for young and older adults.

The accuracy of the Caltrac accelerometer was studied in 28 young (26.1 +/- 1.1 yrs) and 28 older (64.8 +/- 1.0 yrs; M +/- SEM) men and women to determine its usefulness as an activity monitor for young and older adults. Oxygen uptake was measured by indirect calorimetry while subjects walked on a motorized treadmill at six different speeds while wearing an accelerometer on the hip and on the upper back. The test-retest reliability of the Caltrac was r = .95 and r = .98 for young and older subjects, respectively. In the young group, activity counts correlated highly to net caloric expenditure (absolute minus estimated resting expenditure) (hip vs. kcal/kg: r = .89; back vs. kcal/kg: r = .88) when averaged across speeds, but the relationship was only moderate (back: r = .51; hip: r = .46) when the influence of speed was removed. In the older group the correlations were considerably weaker (back: r = .73; hip: r = .25), and essentially zero when the influence of speed was removed. These data indicate that the Caltrac is a highly reliable accelerometer that is useful for assessing qualitative differences in the level of physical activity among groups, but it lacks accuracy in quantifying energy expenditure in individuals, especially in older adults.

Acceleration↗

PubMed1978

Structure-activity studies of hydroxamic acids as direct vasodilators.

A series of beta-hydroxylamine-phenylpropyl hydroxamic acids were prepared. The ability of these compounds to act as hypotensive agents was studied pharmacodynamically. Key structural features for the hypotensive action were identified and correlated to the degree of responses observed. It was ascertained that these compounds do not act through the adrenergic, cholinergic and histaminergic receptor system, but can be classified as direct acting vasodilators.

Animals↗