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Biomedical subjects

S Sarkar

Publications and source records attributed to S Sarkar.

At least 217 records · Page 12Linked to original sources
PubMed1995

Role of routine lumbar puncture in neonatal sepsis.

OBJECTIVE: To evaluate the utility of lumbar puncture done routinely as part of complete workup in neonatal sepsis. METHODOLOGY: Two hundred and nine consecutive lumbar punctures performed in 169 neonates were prospectively evaluated for the diagnosis of meningitis over a 6 month period in a tertiary care referral neonatal unit. RESULTS: Among babies with 'suspected clinical sepsis', five (3.3%) were diagnosed to have meningitis. None of the clinically normal babies with high risk obstetric factors alone had meningitis. The lumbar puncture was traumatic in 22.9%, and in 26.3% the fluid obtained was inadequate for complete analysis. The results were inconclusive in 37% of the cases. CONCLUSION: Based on this study, routine lumbar puncture may not be required in clinically normal newborns with adverse obstetric factors. In babies with clinical sepsis, though the yield is not very high; there are no reliable clinical or laboratory markers to predict which babies will have meningitis and hence these babies would warrant a lumbar puncture.

Birth Weight↗
PubMed1995

Risk factors for development of dehydration in young children with acute watery diarrhoea: a case-control study.

In a case-control study to understand the risk factors for development of life-threatening dehydration, a total of 379 children comprising 243 cases (moderate or severe dehydration) and 136 controls (non or mild dehydration) up to 2 years of age suffering from acute watery diarrhoea were studied. By univariate analysis, the presence of vibrios in stool, withdrawal of breast feeding during diarrhoea, not giving fluids, including oral rehydration solution (ORS), during diarrhoea, frequent purging ( > 8/day), vomiting ( > 2/day) and undernutrition were identified as risk factors. However, by multivariate analysis after controlling for confounders, withdrawal of breast feeding during diarrhoea (odds ratio (OR) = 6.8, p < 0.00001) and not giving ORS during diarrhoea (OR = 2.1, p < 0.006) were identified as significant risk factors. The confounding variables which also contributed significantly to increasing the risk were age ( < or = 12 months; OR = 2.7, p = 0.001), frequent purging ( > 8/day; OR = 4.1, p < 0.00001), vomiting ( > 2/day; OR = 2.4, p = 0.001) and severe undernutrition (%median < or = 60 weight-for-age of Indian Academy of Paediatrics classification; OR = 3.1, p = 0.001). We feel that these findings will be useful for Global and National Diarrhoeal Diseases Control Programmes for formulating intervention strategies for preventing death due to diarrhoeal dehydration.

Acute Disease↗
PubMed1994

Mycotin: a lectin involved in the adherence of Mycobacteria to macrophages.

Pathogenic Mycobacteria colonize host macrophages. Attachment of these organisms to macrophages is the preliminary step prior to invasion of the macrophages by the bacteria. Western blot confirmed that walls of Mycobacterium avium and Mycobacterium tuberculosis contain molecules which are immunologically related to mycotin, a lectin found in Mycobacterium smegmatis. We have demonstrated that the adherence of Mycobacteria to macrophages is significantly inhibited by anti-mycotin antibody or the mycotin-specific sugar, mannan. These observations suggest that prevention of the interaction of mycotin-related molecules on the surfaces of Mycobacteria with mannose-specific receptors on macrophages, offers an important approach for blocking attachment of pathogenic Mycobacteria to macrophages, thereby preventing infection.

Animals↗
PubMed1994

Second cancers following oral and pharyngeal cancers: role of tobacco and alcohol.

BACKGROUND: The exceptionally high rate of second primary cancers among patients with oral and pharyngeal cancers is well recognized, yet there has been limited epidemiologic study of risk factors for second tumors. PURPOSE: To evaluate the relation of smoking and alcohol consumption to the development of second cancers among this high-risk patient group, we conducted a nested case-control study. METHODS: A total of 1090 patients enrolled in a 1984-1985 population-based, case-control study of oral cancer in four areas of the United States were followed through June 1989 for the occurrence of second primary cancers. Information on tobacco and alcohol consumption was obtained from the original interviews and was updated by follow-up interviews obtained for 80 case patients with second cancers and 189 sex-, study area-, and survival-matched cancer patients free of second cancers (control subjects). RESULTS: Tobacco smoking and alcohol drinking each contributed to risk of second cancers, with the effects of smoking more pronounced than those of alcohol. The odds ratios (ORs) for smoking (adjusted for alcohol) rose with duration and intensity of smoking and were strongest for tumors of the aerodigestive tract (oral cavity, pharynx, esophagus, larynx, and lungs), with ORs reaching 4.7 (95% confidence interval [CI] = 1.4-16) among smokers of 40 or more cigarettes per day for 20 or more years. Current smokers as of the baseline survey experienced a fourfold increased risk of a second aerodigestive tract cancer relative to nonsmokers and former smokers. No reduction in risk was associated with cessation of smoking or drinking at or after the index diagnosis, although the short median interval (27 months) between tumor diagnoses limited observation of the effects due to recent cessation. Risk was significantly reduced, however, 5 years after smoking cessation. Among drinkers, second cancer risk was greatest for beer intake, with an OR for a second aerodigestive tract cancer of 3.8 (95% CI = 1.2-12) for 15 or more beers per week. CONCLUSIONS: Oral and pharyngeal cancer patients with the highest intakes of tobacco and alcohol are the ones most prone to develop second primary cancers. IMPLICATIONS: Avoidance of tobacco smoking and alcohol drinking is the most desirable way not only to prevent primary oral cancers, but also to reduce risk of second cancers of the aerodigestive system.

Aged↗
PubMed1994

Overexpression and rapid purification of rabbit fast skeletal troponin I from Escherichia coli: effect of different promoters, host strains, and culture conditions.

Rabbit fast skeletal troponin I (TnIf) cDNA was expressed using two Escherichia coli expression vectors, pRE1 containing the bacteriophage lambda pL promoter and pAED4, a T7 RNA polymerase-based vector. Although both vectors expressed TnIf, overexpression of the target protein was achieved with pAED4. The effect of several parameters such as culture condition, compatible host strain, and inhibition of protein synthesis by rifampicin on the expression of TnIf was investigated. The overexpressed target protein synthesized during a brief induction period of only 2 h was conveniently purified from inclusion bodies by a simple and rapid procedure involving extraction with urea, ultracentrifugation, DE-52 column chromatography, and gel filtration. About 50-75 mg of highly purified TnIf was obtained per liter E. coli culture by this method, which does not involve time-consuming multistep procedures such as affinity and ion exchange chromatography as previously reported in the literature. The isolated unfused protein is stable and is indistinguishable from native protein in all biological parameters examined. The parameters optimized in this report for overexpression of TnIf may also be applicable for other eukaryotic proteins.

Adenosine Triphosphatases↗
PubMed1994

Effect of vitamin A supplementation on diarrhoea and acute respiratory tract infection in children. A double blind placebo controlled trial in a Calcutta slum community.

To determine the effect of a massive single oral dose of vitamin A (200,000 IU) supplementation on diarrhoea and acute respiratory infection (ARI), a double-blind placebo controlled trial involving 174 children under six years of age (excluding infants) was carried out in a Calcutta slum community. Ninety-one children received vitamin A supplementation (experimental group) and 83 children received a placebo (control group). All the children were followed up for six months by active fortnightly surveillance for occurrence of diarrhoea or ARI and their duration. There was no statistically significant difference in the incidence of diarrhoeal episodes or ARI. However, there was a significant difference (p < 0.05) in the average duration of diarrhoea per episode (2.1 vs. 3 days) between the experimental and control groups. Possible beneficial effects of a single oral dose of vitamin A supplementation on the incidence of diarrhoea and ARI could not be demonstrated in the present study.

Acute Disease↗
PubMed1994

Effect of low power microwave on the mouse genome: a direct DNA analysis.

The potential mutagenic effect of low power microwave at the DNA sequence level in the mouse genome was evaluated by direct DNA analysis. Animals were exposed to microwave at a power density of 1 mW/cm2 for 2 h/day at a frequency of 2.45 GHz over a period of 120, 150 and 200 days. HinfI digested DNA samples from testis and brain of control and exposed animals were hybridized with a synthetic oligo probe (OAT 36) comprising nine repeats of 5'-GACA-3'. As compared to control animals, band patterns in exposed animals were found to be distinctly altered in the range of 7-8 kb which was also substantiated by densitometric analysis. Though the mechanism of this rearrangement is not yet clear, the results obtained at the present dose are of significance. This dose, which has been set as the safe limit for general public exposure by the Non-Ionizing Radiation Committee of the International Radiation Protection Association, may imply a need for (re)evaluation of the mutagenic potential of microwaves at the prescribed safe limit for the personnel and people who are being exposed.

Animals↗
PubMed1994

Epidemic of herpes zoster following HIV epidemic in Manipur, India.

Since 1989, injecting drug use (IDU) related HIV infection has affected thousands of young adults in Manipur, a north eastern state of India bordering Myanmar following a similar kind of epidemic in adjoining countries like Thailand and Myanmar. During a clinical surveillance of a group of HIV positive IDUs for a natural history study at Manipur, herpes zoster (HZ) emerged as the most specific early HIV related illness (positive predictive value of 100%) in patients belonging to the age group of 12-45 years. Data collected from the dermatology departments of the two main hospitals of the state revealed that there had been an epidemic of HZ since 1990 (rate of 1990 being 11.3/1000 compared to 6.5/1000 in 1989, P value < 0.0001) among males of 12-45 years. The epidemic of HZ has been attributed to the preceding epidemic of IDU related HIV in the same age and gender group occurring 1 year earlier. HZ should be recognised as a marker condition similar to tuberculosis indicating the necessity of screening for HIV in regions where the dual problem of IDU and HIV exist in young adults.

AIDS-Related Opportunistic Infections↗
PubMed1994

Dietary factors and second primary cancers: a follow-up of oral and pharyngeal cancer patients.

To investigate the possible relationship between dietary factors and the development of multiple primary cancer, a nested case-control study was carried out within a cohort of 1,090 oral and pharyngeal cancer patients. This patient group, enrolled in 1984-1985 in a population-based case-control study conducted in four areas of the United States, was followed up through June 1989 for the occurrence of second primary cancer. Information on a number of risk factors, including diet, ascertained from interviews conducted at baseline (1984-1985) and at follow-up were compared between 80 patients with histologically confirmed second primary cancers (39% in the upper aerodigestive tract, 32% in the lung, 29% elsewhere) and 189 sex- and survival-matched control patients free of second cancers. Although few significant trends emerged, the results were suggestive of a protective effect provided by higher intake of vegetables. Risk of second primary cancers was 40-60% lower among those with the highest levels of intake for total vegetables and most vegetable subgroups, including dark yellow, cruciferous, and green leafy vegetables and legumes. Risks were also nonsignificantly lower among those with high consumption of vitamin C and carotenoids, with the adverse effects of alcohol being most evident among heavy drinkers with low vitamin C or carotenoid intake. There was also some evidence of an interaction between smoking and vitamin C consumption, but numbers of nonsmokers were small. Among other dietary factors considered, positive associations were found with increasing consumption of meats, liver, and retinol. The findings suggest that dietary factors contribute along with alcohol and smoking to the excess risks of second primary cancers among patients with oral and pharyngeal cancers.

Aged↗
PubMed1994

Isolation and characterization of human fast skeletal beta troponin T cDNA: comparative sequence analysis of isoforms and insight into the evolution of members of a multigene family.

A cDNA encoding human fast skeletal beta troponin T (beta TnTf) has been isolated and characterized from a fetal skeletal muscle library. The cDNA insert is 1,000 bp in length and contains the entire coding region of 777 bp and 5' and 3' untranslated (UT) segments of 12 and 211 bp, respectively. The 3' UT segment shows the predicted stem-loop structure typical of eukaryotic mRNAs. The cDNA-derived amino acid sequence is the first available sequence for human beta TnTf protein. It is encoded by a single-copy gene that is expressed in a tissue-specific manner in fetal and adult fast skeletal muscles. Although the human beta TnTf represents the major fetal isoform, the sequence information indicates that this cDNA and the coded protein are quite distinct from the fetal and neonatal TnTf isoforms reported in other mammalian fetal muscles. The hydropathy plot indicates that human beta TnTf is highly hydrophilic along its entire length. The protein has an extremely high degree of predicted alpha-helical content involving the entire molecule except the carboxy-terminal 30 residues. Comparative sequence analysis reveals that the human beta TnTf shares a high level of sequence similarity in the coding region with other vertebrate TnTf and considerably reduced similarity with slow skeletal and cardiac TnT cDNAs. The TnT isoforms have a large central region consisting of amino acid residues 46-204 which shows a high sequence conservation both at the nucleotide and amino acid levels. This conserved region is flanked by the variable carboxy-terminal and an extremely variable amino-terminal segment. The tropomyosin-binding peptide of TnT, which is represented by amino acid residues 47-151 and also includes a part of troponin I binding region, is an important domain of this central segment. It is suggested that this conserved segment is encoded by an ancestral gene. The variable regions of vertebrate striated TnT isoforms reflect the subsequent addition and modification of genomic sequences to give rise to members of the TnT multigene family.

Amino Acid Sequence↗
PubMed1994

The alternative fitness sets which preserve allele trajectories: a general treatment.

A general solution is presented of the problem of specifying all alternative, generally frequency-dependent, (absolute) fitness sets which give rise to the same allele frequency changes and population dynamics as a given fitness set. The one- and two-locus cases are analyzed in detail and the method is then extended to the n-locus case. It is shown that if biological constraints can be used to specify the mean fitness of the population and the relative fitnesses of the heterozygotes, then the allele frequency trajectories determine a unique fitness set.

Alleles↗