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Biomedical subjects

A L Prasad

Publications and source records attributed to A L Prasad.

15 recordsLinked to original sources
PubMed1988

Changes in serum and striatal free amino acids after Venezuelan equine encephalomyelitis virus infection.

The infection with the Venezuelan equine encephalomyelitis virus produced a significant increase in the concentration of alanine, arginine, asparagine, glutamine, isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan, tyrosine, and valine in the striatum of rats. On the contrary, the concentrations of aspartate, GABA, glutamate, and taurine were reduced. Arginine, aspartate, glycine, methionine, phenylalanine, taurine, and tyrosine concentrations were increased in the serum of infected rats. However, the modifications in the content of free amino acids in the striatum and serum of rats that survived the infection were qualitatively and quantitatively different from those detected during the acute phase of the infection.

Amino Acids↗
PubMed1988

Huntington's disease: studies on brain free amino acids.

We studied the levels of free amino acids in putamen and Brodmann's area 10 of 12 patients who died with Huntington's disease and 13 non-neurologic controls. GABA, glutamate and alpha-amino-n-butyric acid concentrations were found to be reduced in putamen of Huntington's disease patients. In Brodmann's area 10 the levels of glutamate, histidine and lysine were decreased, but the content of aspartate, GABA, glycine, serine and taurine was increased in the same group of patients.

Adult↗
PubMed1986

Free amino acids in the striatum of mice infected with Venezuelan equine encephalomyelitis virus.

In mice inoculated with the Guajira strain of Venezuelan equine encephalomyelitis virus, a significant increase in the concentration of arginine, isoleucine, leucine, glycine, phenylalanine, serine, threonine, and valine was produced in the striatum. On the contrary, the levels of alanine, asparagine, aspartate, GABA, glutamine, and taurine were reduced. No changes were observed in the striatal content of tyrosine and glutamic acid.

Amino Acids↗
PubMed1984

A clinical profile of donovanosis in a non-endemic area.

The diagnosis of donovanosis is seldom made in a non-endemic region, because it is usually overlooked as an aetiologic diagnosis of genital ulcers. Clinical suspicion is a yardstick in its diagnosis and has been illustrated in the present study. Its frequency was found to be 3.14% of all sexually transmitted diseases. Unmarried males of vulnerable sexual age were commonly affected. They came from a low socioeconomic strata. The incubation period and duration of disease was variable. The genitalia were primarily affected. The ulcerogranulomatous variety was seen commonly, though unusual expression of the disease was also recorded. The importance of repeated tissue smears and/or histopathology in certain clinical variants is emphasized.

Adolescent↗
PubMed1977

Is dopamine a neurohormone of the adrenal medulla? Studies with morphine stimulation.

Dopamine (da) concentrations in rat adrenals, plasma and brain were variably elevated 1 h after a large parenteral dose of morphine. In adrenals, unlabelled DA increased 2-fold and labelled DA, synthesized from 3H-tyrosine, increased more than 4-fold. The increases could be prevented by inhibition of DA-synthesizing enzymes and spinal cord transection, respectively. Labelled DA in plasma increased 2.7-fold after morphine in intact rats but did not increase in those with spinal cord transection. It is concluded that: (1) morphine stimulates the adrenal by increasing nerve impulse flow, (2) increased nerve impulse flow increases DA synthesis and levels, and (3) the increased DA levels result in increased release of DA into the bloodstream.

Adrenal Medulla↗
PubMed1976

Correlation of behavioural inhibition or excitation produced by bromocriptine with changes in brain catecholamine turnover.

The dopamine agonist, bromocriptine, produced either inhibition or stimulation of motor behaviour in rats depending upon the dose and time after administration. Stimulation of motor activity occurred only with high doses after a 1-2 h delay. Both inhibition and stimulation were associated with decreased turnover of dopamine in the brain. Release of noradrenaline in brain and noradrenaline plus adrenaline in adrenal varied with motor activity. It is suggested that low doses of bromocriptine inhibit behaviour by activating an inhibitory presynaptic receptor, resulting in reduced synthesis and release of dopamine, whilst high doses cause behavioural excitation by activating the post-synaptic dopamine receptor.

Animals↗
PubMed1975

Normalization of brain serotonin by L-tryptophan in levodopa-treated rats.

To test possible biochemical mechanisms by which L-tryptophan may reverse mental side effects of levodopa therapy in parkinsonism we administered levodopa, 250 mg per kilogram intraperitoneally, alone and with L-tryptophan, 500 mg per kilogram intraperitoneally, to rats pretreated with the peripheral dopa decarboxylase inhibitor, carbidopa (25 mg per kilogram). Rats were decapitated 0.5, 1, and 2 hours following amino acid injection and brain levels of amino acids, amines, and acid metabolites were determined. As expected, levodopa alone reduced tryptophan and serotonin and increased dopa and dopamine at the 1 and 2 hour intervals. Concurrent administration of L-tryptophan did not significantly alter the increased dopa and dopamine but did restore serotonin levels to within normal range at all time points. If similar events occur in parkinsonian patients, normalization of brain serotonin and not competitive reduction of brain dopa and dopamine may be the basis for the improvement in mental status.

Animals↗