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Biomedical subjects

A K Chaudhuri

Publications and source records attributed to A K Chaudhuri.

At least 19 recordsLinked to original sources
PubMed2002

J/psi suppression in Pb + Pb collisions: a conventional description.

We have analyzed the latest NA50 data on J/psi suppression in Pb + Pb collisions. J/psi production is assumed to be a two-step process: (i) formation of a cc- pair, which is accurately calculable in QCD, and (ii) formation of a J/psi meson from the cc- pair, which can be conveniently parametrized. The parameters of the model were fixed from experimental data on the total J/psi cross section as a function of effective nuclear length. The model gives an excellent description of NA50 data on the ET dependence of the J/psi-to-Drell-Yan ratio. It was applied to the ET dependence of J/psi at RHIC energies, and predicts a much larger suppression of J/psi, in agreement with other model calculations.

Journal Article↗
PubMed2001

The central Scotland Escherichia coli O157:H7 outbreak: risk factors for the hemolytic uremic syndrome and death among hospitalized patients.

Little is known about risk factors for complications of Escherichia coli O157:H7 infection in adults. The 1996 outbreak in central Scotland involved the largest number of adult case patients in whom hemolytic uremic syndrome (HUS) developed and, ultimately, the largest number of deaths associated with E. coli O157:H7 infection that has yet been recorded. We investigated risk factors for HUS in a retrospective study of all hospitalized case patients in this outbreak. Of 120 case patients, 34 had HUS develop, 28 of whom were adults. Sixteen adults died. Significant risk factors for HUS were age <15 years or >65 years (odds ratio [OR], 4.4; 95% confidence interval [CI], 1.3-14.4), hypochlorhydria (OR, 6.7; 95% CI, 1.9-24.0), and coincidental antibiotics (OR, 4.7; 95% CI 1.4-16.5). Factors associated with HUS were as follows: white blood cell count >20 x 10(9) cells/L (OR, 8.25; 95% CI, 1.1-60.3), neutrophil count >15 x 10(9) cells/L (OR, 8.5; 95% CI, 1.5-50.1), and serum albumin level <35 g/L (OR, 7.2; 95% CI, 1.2-42.5) < or =3 days after symptom onset. Deaths were confined to case patients >65 years of age. Early identification of risk factors for HUS is vital and could select case patients for trials of preventative and treatment therapies.

Adolescent↗
PubMed2000

Preliminary studies on the anti-inflammatory and analgesic activity of the methanolic fraction of the root extract of Tragia involucrata Linn.

Tragia involucrata has been widely used in the traditional medicinal system for the treatment of a variety of diseases. The effect of methanolic extract of T. involucrata was studied in different experimental animal models and it was revealed that the extract possesses significant analgesic and anti-inflammatory activity.

Analgesics, Non-Narcotic↗
PubMed2000

Temperature dependent luminescence characteristics of Sm3+-doped silicate glass.

We report here on the optical characterisation of Sm3+ (5 wt%): SiO2 + Al2O3 + Li2O + Na2O + MgO glass from the measurements of optical absorption spectra (at 300 K), total luminescence spectra (10-300 K) and fluorescence lifetimes (10-300 K) of the prominent emission transitions of the Sm3+ ions. Besides its spectral properties, physical and nonlinearity characterising property parameters have also been computed to understand the optical dispersive power of this glass. By the application of Judd-Ofelt parameters (omega(lambda)) of the measured absorption spectrum, the radiative transition probability factors (A) and stimulated emission cross-section (sigma(p)E) of the observed fluorescent levels have been analysed. Both emission intensity and measured lifetimes of the prominent luminescent transition (4G(5/2) --> 6H(7/2)) concerning Sm3+-glass has been showing a descending trend with the rise in temperature with N2-laser (337.1 nm) as the source of excitation.

Glass↗
PubMed1999

Neuropsychopharmacological profile of the methanolic fraction of Bryophyllum pinnatum leaf extract.

Neuropharmacological studies were conducted in experimental animals (rats and mice) with the methanolic fraction of Bryophyllum pinnatum leaf extract. The fraction produced alteration of behaviour pattern, caused dose-dependent potentiation of pentobarbitone sleeping time and had significant analgesic activity. Significant reduction of exploratory behaviour and loss of residual curiosity were among the effects observed with the fraction. The observations suggest that the methanolic fraction of Bryophyllum pinnatum possesses a potent CNS depressant action.

Analgesia↗
PubMed1998

Studies on the possible mechanism of the gastric mucosal protection by Calotropis procera--involvement of 5-lipoxygenase pathway.

The role of chloroform fraction of Calotropis procera root extract on different experimental ulcer models in rats was investigated. The extract demonstrated significant anti-ulcer activity against aspirin, indomethacin, ethanol, indomethacin + ethanol, or stress-induced ulcerations. Significant inhibition of gastric secretory volume and total acidity in pylorus ligated rats were observed to occur with the extract. It was also observed that the root extract significantly inhibited arachidonic acid metabolism induced by soyabean lipoxygenase. The results suggest that the anti-ulcer activity of the extract might be attributable to the inhibition of 5-lipoxygenase (5-LO).

Animals↗
PubMed1996

Bacterial meningitis--the importance of cerebro-spinal fluid examination.

The role of lumbar puncture in bacterial meningitis has been debated in recent years, especially in the presence of worsening headache, alteration of conscious level, focal neurological signs, papilloedema or a haemorrhagic rash. However valuable bacteriological and epidemiological information will be lost if lumbar puncture is avoided, despite blood cultures being taken. This loss of information will be highlighted if pre-admission antibiotics are administered (this should now be standard practice).

Adolescent↗
PubMed1994

A severe outbreak of E. coli O157 in two psychogeriatric wards.

In October 1990 there was a severe outbreak of Escherichia coli O157 in two psychogeriatric wards of a large psychiatric hospital in Lanarkshire. There were 11 cases (eight patients and three staff), of whom four died (all patients). Two cases, one staff and one patient (the likely index case) were identified serologically after the outbreak was over. E. coli O157 was not cultured from any food, water or milk samples, and the evidence suggests that the index case had eaten food brought into the hospital. The results also suggest that the incubation period of the organism may be longer than is currently recognized, particularly for person-to-person spread. A Fatal Accident Inquiry was held into the deaths, and the Sheriff's Determination is discussed together with the implications of the results for infection control procedures.

Adolescent↗
PubMed1993

Studies on the mechanism of anti-inflammatory and anti-ulcer activity of Pluchea indica--probable involvement of 5-lipooxygenase pathway.

The effect of the methanolic fraction of Pluchea indica Less. root extract was evaluated on various models of inflammation and ulcer in vivo to assess the role of P. indica on the 5-lipoxygenase pathway of prostaglandin synthesis. Studies presented here reveal significant antiinflammatory activity of the fraction on Arachidonic acid, Platelet activation factor and Compound 48/80-induced paw oedema. There was significant inhibition of spontaneous as well as compound 48/80-induced histamine release from mast cells. Ulcer studies revealed significant protective action of the fraction on indomethacin, alcohol and indomethacin-alcohol induced ulceration. There was significant decrease of gastric volume and acidity in pylorus ligated rats. Studies also showed, significant protective action of the same on gastric mucosa.

Animals↗
PubMed1993

Isolation of a toxin from jellyfish Acromitus rabanchatu and its effect on skeletal muscle.

A toxin (T-Ar) from the crude extract of jellyfish Acromitus rabanchatu was purified by (NH4)2SO4 fractionation followed by ion-exchange chromatography on DEAE-cellulose column. The mol. wt of T-Ar was found to be about 182,000. T-Ar reversibly blocked the twitch response of rat diaphragm muscle stimulated either indirectly or directly. It also reversibly blocked the twitch responses of chick biventer-cervicis muscle preparations. T-Ar failed to alter the contractures of the denervated rat diaphragm muscle preparation induced by acetylcholine, potassium chloride and caffeine. Similarly, acetylcholine and carbachol-induced contractures on chick biventer-cervicis muscle preparation were not influenced by T-Ar. The T-Ar-induced blockade of twitch responses of rat phrenic nerve-diaphragm was enhanced in high Na+ or low Ca2+ medium, and reduced in low Na+ or high Ca(2+)-containing medium. The results suggest that the toxin (T-Ar) possesses a direct paralysing effect on the muscle membrane.

Acetylcholine↗
PubMed1993

Infection control in hospitals: has its quality-enhancing and cost-effective role been appreciated?

A review of data from surveys worldwide, including the United Kingdom and the United States, or morbidity and mortality and costs incurred as direct consequences of hospital-acquired infection is presented. These data testify to the role of hitherto somewhat undervalued Infection Control in hospitals as a key factor in the quality of medical care and also establish its contribution towards cost-effectiveness in various health care systems, including the National Health Service in the UK (NHS). It is appropriate, therefore, for Infection Control to be accorded proper appreciation and adequate funding. The achievement of these aims is likely to be helped by the recent changes in the NHS management system and supported by the requirements of Medical Audit and Hospital Accreditation Schemes.

Cost-Benefit Analysis↗
PubMed1991

Transient leukaemia cutis in hairy-cell leukaemia.

Leukaemic skin infiltration is uncommon in hairy-cell leukaemia (HCL), a neoplasm characterized by the presence of uniform mononuclear cells with cytoplasmic projections in the blood, bone marrow and spleen. A case is reported in which leukaemia cutis was a transient phenomenon, appearing soon after the onset of a continuous pyrexia associated with marked systemic upset which was subsequently shown to be due to pulmonary tuberculosis.

Humans↗