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Biomedical subjects

S Biswas

Publications and source records attributed to S Biswas.

At least 199 records · Page 11Linked to original sources
PubMed1988

Involvement of GABA in environmental temperature-induced change in body temperature.

Acute exposure of adult male albino rats (110-120 g) to higher environmental temperature (40 +/- 1 degrees C) increased body temperature (BT). This increase of BT was also dependent on the duration of exposure. Treatment with muscimol (1 mg/kg, i.p.), a GABA agonist, produced hypothermia at room temperature (28 +/- 1 degree C) and resistance to increase the body temperature when exposed to higher temperature (40 +/- 1 degree C). Administration of bicuculline (1 mg/kg, i.p.), a GABA antagonist, on the other hand, enhanced BT more than that observed in control (normal) rat exposed to higher temperature (40 +/- 1 degree C), although at room temperature bicuculline treatment did not show any effect on BT. Pretreatment with ethanolamine-O-sulfate (EOS) (2 g/kg, s.c.), a GABA transaminase inhibitor, to rats exposed to higher temperature increased BT as in control (normal) rat. Inhibition of central GAD activity with mercaptopropionic acid (MPA) (70 mg/kg, i.p.) produced resistance to increase BT during its period of action when rats were exposed to higher environmental temperature (28 +/- 1 degree C). These results thus suggest that central inhibitory neuron, GABA, plays a regulatory role in thermoregulation.

3-Mercaptopropionic Acid↗
PubMed1988

Possible involvement of central cholinergic-serotonergic interaction in natural sleep.

Administration of L-5-hydroxytryptophan (L-5-HTP) (200 mg/kg, p.o.) to adult male hamsters (110-120 g) increased non-rapid-eye-movement (NREM) as well as rapid-eye-movement (REM) sleep, with an increase of total sleep time. Methysergide (10 mg/kg, i.p.) facilitated REM sleep and inhibited NREM sleep. Both REM and NREM sleep disappeared with atropine (5 mg/kg, i.p.) both in absence and in presence of L-5-HTP (200 mg/kg, p.o.). Physostigmine (0.1 mg/kg, i.p.) increased REM sleep and decreased NREM sleep without altering the total sleep time. Co-administration of physostigmine (0.1 mg/kg, i.p.) and methysergide (10 mg/kg, i.p.) increased REM but blocked completely NREM sleep. These results suggest that the serotonergic system involved in REM sleep is regulated by the interaction of cholinergic receptor activity and the involvement of the cholinergic system in NREM sleep is regulated by the interaction of serotonergic receptor activity.

5-Hydroxytryptophan↗
PubMed1987

Neuropeptide Y alters monoamine turnover in the rat brain.

The effects of intracerebroventricular administration of neuropeptide Y (NPY) on central monoamine turnover were studied in rats treated with alpha-methyl-p-tyrosine (alpha-MPT). NPY decreased noradrenaline turnover in the brainstem, hypothalamus, midbrain and hippocampus. Dopamine turnover was decreased in the brainstem and striatum of NPY-treated rats. Although alpha-MPT did not seem to affect the turnover of serotonin, the concentration of this amine after the administration of NPY was higher in the brainstem, hypothalamus and striatum. Our results suggest that NPY may play a role in the modulation of monoamine turnover in the central nervous system.

Animals↗
PubMed1987

A multistate Markov chain model for evaluating a sterilization policy.

"A multistate Markov chain model corresponding to varying fertility and mortality rates at different levels of surviving children of a couple was developed. Asymptotic probabilities of having a fixed number of children have been worked out." The implied geographical focus is on India.

Asia↗
PubMed1984

2-Mercapto-ethanol enhancement of agglutination reaction--a possible in vitro serological correlate for assessment of functional immunity in simian malaria.

Conventional indirect haemagglutination test was performed in rhesus monkey sera (collected from Plasmodium knowlesi infected animals) with and without prior treatment of sera with 2-mercapto-ethanol (2-ME). Surprisingly, many sera samples showed significant enhancement of final titre with 2-ME. The 2-ME enhancement effect was more pronounced in the sera of hyperimmune monkeys on further injection of antigen or parasites. It was also noticeable in the sera during primary drug-suppressed P. knowlesi infection and appeared to have a bearing on the immune status of the animals to rechallenge. The use of a soluble antigen prepared from P. knowlesi infected erythrocytes was found to be essential in IHA test to demonstrate the 2-ME enhancement effect. Antigen prepared from freed parasites (commonly used) failed to show a similar effect in IHA. The possible role of certain T-lymphocyte products - antigen binding, non-agglutinating, 2-ME sensitive molecules - in malarial immunology has been proposed.

Animals↗
PubMed1984

Overproduction of discoidin I by a temperature-sensitive motility mutant of Dictyostelium discoideum.

Dictyostelium discoideum MC2 is a temperature-sensitive motility mutant of AX3. Mutant cells are incapable of growth, phagocytosis, and migration under restrictive conditions (Kayman et al., J. Cell Biol. 92:705-711, 1982). We show here that at the restrictive temperature MC2 cells grown axenically or on bacteria synthesized excessive quantities of the lectin discoidin I. By two-dimensional gel electrophoresis and peptide mapping, the proteins overproduced by MC2 cells were indistinguishable from discoidin I synthesized at lower levels in AX3 cells. At least two of the three species of discoidin I were overproduced. This protein family constituted 9% of the total protein in cells that were incubated overnight at 27 degrees C in axenic medium. Although MC2 cells are defective in nutrient uptake under restrictive conditions, the overproduction of discoidin I did not appear to be part of a pleiotropic response to starvation. We propose that transcription of the coordinately regulated discoidin I genes is altered in mutant cells. This alteration may be related to the motility defects manifested by MC2.

Cell Movement↗