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Biomedical subjects

R V Bhat

Publications and source records attributed to R V Bhat.

At least 73 records · Page 4Linked to original sources
PubMed1990

Selective changes in sensitivity to cholinergic agonists and receptor changes elicited by continuous physostigmine infusion.

A reduction in nicotinic receptors has been observed in brains of patients with Alzheimer's disease, and physostigmine, an indirect acting cholinergic agonist, has been suggested as a treatment of this disease. However, the effects of physostigmine treatment have not been thoroughly characterized. The central and peripheral effects of physostigmine were evaluated in C57BL/6 mice using a battery of behavioral and physiological tests that included respiratory rate, Y maze crossing and rearing activities, heart rate and body temperature. With the exception of the heart rate test, which was blocked by a peripheral muscarinic antagonist, all responses to physostigmine measured in the test battery seem to be mediated centrally. Sensitivity to physostigmine and to nicotine and oxotremorine were examined as were nicotinic and muscarinic receptors after continuous infusion of physostigmine. Mice (C57BL/6) continuously infused with physostigmine (0.1 mg/kg/h) for 10 days developed marked tolerance to physostigmine and exhibited a slight decrease in sensitivity to nicotine; sensitivity to oxotremorine was largely unaltered. Chronic physostigmine treatment resulted in a 62% inhibition of AChE activity and elicited a significant increase in the amount of L-[3H] nicotine binding in midbrain, hippocampus, striatum and colliculi; alpha-[125I]bungarotoxin and [3H]quinuclidinyl benzilatl binding were not changed. Although physostigmine treatment might partially reverse the reduction of brain nicotinic receptors seen with Alzheimer's disease, it is questionable whether it would be effective for a prolonged period since the up-regulated nicotinic receptors may not have normal function.

Acetylcholinesterase↗
PubMed1989

Outbreak of trichothecene mycotoxicosis associated with consumption of mould-damaged wheat production in Kashmir Valley, India.

During June to September, 1987, there were reports that a considerable segment of the population of Kashmir Valley, India, were affected by a gastrointestinal disorder. Epidemiological investigations and laboratory based studies indicated that the outbreak was associated with the consumption of bread made from mould-damaged wheat. The disease was not age or sex specific. Evidence of mould damage of wheat consisted of the presence of moulds (such as Fusarium sp, Aspergillus sp), and varying quantities of trichothecene mycotoxins (such as deoxynivalenol, nivalenol, acetyldeoxynivalenol, T-2 toxin) in samples tested. The symptoms were reproduced in dogs fed extracts of contaminated samples. The finding that trichothecene mycotoxins, especially deoxynivalenol trichothecene, cause symptoms in man emphasizes the need for a reappraisal of its safety limits in food.

Adolescent↗
PubMed1989

Production of deoxynivalenol by Fusarium isolates from samples of wheat associated with a human mycotoxicosis outbreak and from sorghum cultivars.

Fusarium isolates from specific diseased sorghum plants and rain-soaked wheat and wheat flour associated with human mycotoxicosis in India have been screened for their toxigenic potential. Of the 322 isolates screened, 11 isolates were found to produce deoxynivalenol in concentrations ranging from 0.01 to 186 micrograms g-1. The occurrence of deoxynivalenol-producing fusaria in a nontemperate region and deoxynivalenol production in low concentrations by Fusarium moniliforme are reported for the first time.

Disease Outbreaks↗
PubMed1989

A study of recorded cases of foodborne diseases at Hyderabad during 1984 and 1985.

Foodborne diseases are a health hazard and a cause of morbidity and mortality in developing countries. Surveillance of foodborne diseases is neglected in India as in most developing countries. A study of case reports for 2 years in a referral hospital is reported. Most of the outbreaks (88%) were found to involve 2-10 persons. About 52% of those affected were found to be below 14 years of age. A seasonal character was observed with more outbreaks being recorded in summer months. Twenty-three per cent of the incidents were observed to occur at home. The predominant symptom in these outbreaks was vomiting with or without diarrhoea. In about 38% of the cases, the vehicle of transmission was not mentioned while in the recorded instances it was stale food (19%); biryani (14%), usually meat preparation with rice; stale biryani (11%) or milk-based sweets (9.5%). The establishment of a National Foodborne Disease Surveillance system is suggested.

Adolescent↗
PubMed1988

Bioactivation of catechol in rat and human bone marrow cells.

o-Benzoquinone-glutathione (GSH) conjugate formation and covalent binding of [14C]catechol to protein were utilized as probes of bioactivation of catechol in both rat and human white bone marrow cell systems. Conjugate formation and binding occurred in the absence of exogenous hydrogen peroxide, but were markedly stimulated by its addition. Protein-binding and conjugate formation using rat cells in the presence of exogenous peroxide were increased by the presence of phenol whereas GSH and hydroquinone inhibited binding. Similarly, protein-binding in the absence of exogenous peroxide was inhibited by GSH and exacerbated by phenol. Prostaglandin synthase, the peroxidatic function of which may also utilize hydrogen peroxide as a substrate, appeared on the basis of experiments using arachidonic acid to play only a minor role in bioactivation of catechol in rat bone marrow cells. These results show that peroxide-dependent bioactivation of catechol occurs in rat and human bone marrow cells and that hydroquinone and GSH inhibit whereas phenol stimulates bioactivation.

Animals↗
PubMed1988

Mould deterioration of agricultural commodities during transit: problems faced by developing countries.

Huge quantities of agricultural commodities are being either imported or exported by the developing countries. The commodities have to be transported from the fields of cultivation to the centres of consumption, considerable time being taken for the movement not only because of long distances but also because of various socio-economic, environmental and biological reasons. These commodities are likely to be damaged by mould growth and subsequent aflatoxin accumulation. If the contamination occurs during transit, often no insurance cover for the risk is available. Because of different methods of sampling followed in the exporting and importing countries it is often difficult to define the exact responsibility of the development of aflatoxin as having taken place during transit. The statistics of the export of aflatoxin high-risk commodities like red pepper (chillies), cotton seed and groundnut extractions clearly, for the last decade, demonstrate the extent of loss suffered by the exporting countries because of aflatoxins. The problem of mould damage and mycotoxin contamination can be minimised by improving facilities for storage at ports and transit points as well as on ships.

Aflatoxins↗
PubMed1984

Aspergillus parasiticus growth and aflatoxin production on black and white pepper and the inhibitory action of their chemical constituents.

Aspergillus parasiticus Speare NRRL 2999 growth and aflatoxin production in black and white pepper and the penetration of the fungus in black pepper corn over various incubation periods were studied. Also, the effects of piperine and pepper oil on growth and aflatoxin production were studied. Under laboratory conditions, black and white pepper supported aflatoxin production (62.5 and 44 ppb (ng/g), respectively) over 30 days of incubation. Fungal growth measured in terms of chitin was considerably less in white pepper than in black pepper. A histological study of black pepper corn showed the fungus penetrating up to the inner mesocarp and establishing itself in the middle mesocarp. Piperine and pepper oil were found to inhibit fungal growth and toxin production in a dose-dependent manner. Thus, both black and white pepper could be considered as poor substrates for fungal growth and aflatoxin production.

Aflatoxin B1↗
PubMed1978

Endemic familial arthritis of Malnad an outbreak in Southern India.

An outbreak of a peculiar joint disease affecting the hip and knee had occurred during the last decade or so, afflicting about 140 families in parts of Malnad in Southern India. Results of epidemiological studies suggest that a recent change in the environment had perhaps precipitated the disease in a genetically susceptible population.

Adolescent↗