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Biomedical subjects

R A Dhume

Publications and source records attributed to R A Dhume.

At least 19 recordsLinked to original sources
PubMed1994

Influence of lateral posture on sweating: does posture alter the sympathetic outflow to the sweat glands?

Our unpublished observation that a lateral decubitus posture influences the pattern of sweating was systematically tested by measuring galvanic skin resistance (GSR). Changes in the GSR between two electrodes placed on skin was used to quantify the degree of sweating. In the lateral posture, sweating is inhibited on the lower half and stimulated on the upper half and reversal of the lateral posture induces sweating on the opposite half of the body. This observation suggests that the autonomic nervous system is controlled at least in part, by body posture.

Adolescent↗
PubMed1991

A comparative study of the driving effects of dextroamphetamine and yogic meditation on muscle control for the performance of balance on balance board.

The work is aimed to compare the relative strength of dextroamphetamine and yogic meditation on the performance of 3 different groups of medical students to concentrate on the task to balance on a balance board. Group A subjects were mediators, group B subjects were given orally 5 and 10 mg of dextroamphetamine in a capsule, 1 hr prior to the test. Group C subjects were given same capsule but with lactose in place of the drug (placebo). This last groups served as control for the study. The balance index calculated taking into account their balance time and error score at each trial of 5 min duration showed that the performance of the group B (drug) had declined with overall percentile fall of 40.6% as compared to the performance of the controls (placebo) whereas, the performance of Group A (meditators) went on steadily and progressively increasing throughout the period of 10 trial days with overall percentile rise of 27.8%. The results were conclusive to confirm earlier reports that amphetamine is not of use for improvement of task rather, it deteriorates the task performance. Contrary to that, yogic meditation is of merit to achieve concentration for mental as well as physical task.

Adolescent↗
PubMed1990

Effects of medial septal stimulation & its blockade with atropine on hippocampal rhythmical slow activity in free-moving rabbits.

The influence of the medial septal nucleus (MSN) on hippocampal rhythmical slow activity (RSA) was investigated in hunger motivated free-moving rabbits. Single unit activity of 29 CA3 dorsal hippocampal neurones was studied under two paradigms viz., electrical stimulation (3v/1msec/5Hz) and chemical blockade of atropine-sensitive medial septal cells (dose of 5 micrograms in 5 microliters). The analysis of interspike interval sample histograms recorded with Apple II, along with single unit neuronal spikes recorded on polygraph showed bimodal pattern with two peaks; one at bin 10-20 (high frequency) and second at bin 100-300 (theta frequency). On stimulation of MSN, there was total suppression of bin 100-300 with peaks at bin 1-20 and at bin greater than 1000 (very low frequency). Blockade of cholinergic receptors at MSN showed reduction of bin 100-300 and peak at bin 700- greater than 1000; this was followed by gradual decrease of spike's amplitude and thereafter its total abolition. The results indicate that the septal region is not a pacemaker per se in the genesis of hippocampal RSA (theta rhythm), but serves more in the nature of a relay station for a number of inputs and that its influence on the hippocampal electrical activity depends on the integrity of cholinergic inputs, be it from hippocampus proper or from mid-brain reticular formation.

Animals↗
PubMed1989

Effect of dorsal hippocampal lesion compared to dorsal hippocampal blockade by atropine on reference memory in vision deprived rats.

In order to study the primacy of the hippocampus in place learning function 24 male adult albino rats were hippocampally-lesioned in dorsal hippocampus involving fornical damage (group I); sham operated for comparison with group I (group II); cannulated for instillation of atropine sulphate in the same loci as group I (group III); and cannulated for instillation of saline which served as control for group III (group IV). All the animals were enucleated and their reference memory (long-term memory) was tested, using open 4-arm radial maze. There was loss of reference memory in groups I and III. However, hippocampally-lesioned animals, showed recovery of reference memory deficit within a short period of 10 days or so. Whereas atropinized animals showed persistent reference memory deficit as long as the instillation effect continued. The mechanism involved in the recovery of reference memory in hippocampally-lesioned animals and persistent deficit of reference memory in atropinized animals has been postulated to explain the primacy of hippocampus in the place learning function under normal conditions.

Animals↗
PubMed1982

Water as entrainer of circadian running activity in rat.

The present work is designed to study the competing influence of periodic presentation of water on the running activity of the rat having free access to the cues fulfilling his instinctual drives, namely, food, water, male rat and primed female. Seven male, adult albino rats were used for the study. The 24 hour activity shift patterns of the incentive drives for food, water, male rat and primed female were recorded with the help of a maze-cum-activity cage with an automatic recording system fabricated in the laboratory, and under different schedules of periodic presentation of water. It was observed that the activity pattern shifted towards the drinking period with burst of running preceding water presentations. The findings of this study show that periodic water presentation is as significant as periodic food presentation in entraining the circadian running activity of the rat.

Animals↗