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Biomedical subjects

S Gupta

Publications and source records attributed to S Gupta.

At least 181 records · Page 10Linked to original sources
PubMed2002

Comparative antimutagenic and anticlastogenic effects of green tea and black tea: a review.

Tea is the most popular beverage next to water, consumed by over two-thirds of the world's population. It is processed in different ways in different parts of the world to give green, black or oolong tea. Experimental studies have demonstrated the significant antimutagenic and anticlastogenic effects of both green and black tea and its polyphenols in multiple mutational assays. In the present review, we have attempted to evaluate and update the comparative antimutagenic and anticlastogenic effects of green tea, black tea and their polyphenols in different test systems, based on available literature. Existing reports have suggested that the protective effects of black tea is as good as green tea, however, more studies on black tea and its polyphenols are needed before a final conclusion can be made.

Animals↗
PubMed2002

Risk factors for pneumonia in infants and young children and the role of solid fuel for cooking: a case-control study.

We evaluated the risk factors for childhood pneumonia with particular reference to indoor air-pollution associated with solid fuel use for cooking (e.g. coal, wood, dung), using a case-control study in a children's hospital in Calcutta. Cases were 127 children aged 2-35 months of either sex admitted with pneumonia and controls were 135 children attending their immunization clinic. Solid fuel use (odds ratio = 3.97, CI = 2.00-7.88), history of asthma in the child (OR = 5.49, CI = 2.37-12.74), poor economic status indicator (OR = 4.95, CI = 2.38 to 10.28), keeping large animals (OR = 6.03, CI = 1.13-32.27) were associated with high risk of pneumonia after adjusting for confounding (logistic regression analysis). Nearly 80% of people in India use such smoke producing fuel and the population attributable risk would be very high. This finding has important health policy implications. Furthermore, history of asthma is a useful prognostic indicator for early action for prevention of severe pneumonia.

Air Pollution, Indoor↗
PubMed2002

Sodium valproate in the management of painful neuropathy in type 2 diabetes - a randomized placebo controlled study.

OBJECTIVE: To study the effectiveness and safety aspects of sodium valproate in the management of painful neuropathy in patients of type 2 diabetes mellitus. MATERIAL AND METHODS: A randomized double-blind placebo controlled trial of sodium valproate was done in type 2 diabetic patients to assess its efficacy and safety in the management of painful neuropathy. We screened 60 patients but eight patients could not complete the study; hence, the present study was done on 52 patients. Each patient was assessed by clinical examination, pain score by short form of the McGill pain questionnaire (SF-MPQ) and electrophysiological examination, which included motor and sensory nerve conduction velocity, amplitude and H-reflex initially and at the end of 1 month of treatment. RESULTS: Significant improvement was noticed in the pain score of patients receiving sodium valproate in comparison to patients receiving placebo at the end of 1 month (P < 0.05). The changes in electrophysiological data were not significant. The drug was well tolerated by all patients except one who developed a raised aspartate transaminase (AST)/alanine transaminase (ALT) level after 15 days of treatment. CONCLUSION: Sodium valproate is a well-tolerated drug and provides significant subjective improvement in painful diabetic neuropathy. These data provide a basis for future trials of longer duration in a larger group of patients.

Adult↗
PubMed2002

Biochemical and molecular basis of thimerosal-induced apoptosis in T cells: a major role of mitochondrial pathway.

The major source of thimerosal (ethyl mercury thiosalicylate) exposure is childhood vaccines. It is believed that the children are exposed to significant accumulative dosage of thimerosal during the first 2 years of life via immunization. Because of health-related concerns for exposure to mercury, we examined the effects of thimerosal on the biochemical and molecular steps of mitochondrial pathway of apoptosis in Jurkat T cells. Thimerosal and not thiosalcylic acid (non-mercury component of thimerosal), in a concentration-dependent manner, induced apoptosis in T cells as determined by TUNEL and propidium iodide assays, suggesting a role of mercury in T cell apoptosis. Apoptosis was associated with depolarization of mitochondrial membrane, release of cytochrome c and apoptosis inducing factor (AIF) from the mitochondria, and activation of caspase-9 and caspase-3, but not of caspase-8. In addition, thimerosal in a concentration-dependent manner inhibited the expression of XIAP, cIAP-1 but did not influence cIAP-2 expression. Furthermore, thimerosal enhanced intracellular reactive oxygen species and reduced intracellular glutathione (GSH). Finally, exogenous glutathione protected T cells from thimerosal-induced apoptosis by upregulation of XIAP and cIAP1 and by inhibiting activation of both caspase-9 and caspase-3. These data suggest that thimerosal induces apoptosis in T cells via mitochondrial pathway by inducing oxidative stress and depletion of GSH.

Apoptosis↗
PubMed2002

A set of cattle microsatellite DNA markers for genome analysis of riverine buffalo (Bubalus bubalis).

One hundred and eight microsatellite primer pairs, originally identified from cattle, were evaluated for their applicability in buffalo. Eighty-one primer pairs (75%) amplified discrete products, and of these, 61 pairs (56%) gave polymorphic band patterns on a panel of 25 buffaloes. The mean number of alleles per polymorphic marker was 4.50 +/- 0.20, and the mean heterozygosity per polymorphic marker was 0.66 +/- 0.02. Successful genotyping of buffaloes using cattle specific primers suggests that the latter can be a valuable resource for genome analysis in bubaline species.

Animals↗
PubMed2002

Chlamydia pneumoniae and atherosclerosis -- what we know and what we don't.

The clinical manifestations of atherosclerosis include coronary artery disease (CAD), stroke, abdominal aortic aneurysm and peripheral vascular disease. World-wide, CAD and stroke are the leading causes of death and disability. The recognition of atherosclerosis as an inflammatory disease in its genesis, progression and ultimate clinical manifestations has created an interesting area of vascular research. Apart from those well-known traditional risk factors for atherosclerosis, novel and potentially treatable atherosclerotic risk factors such as homocysteine (an amino acid derived from the metabolism of dietary methionine that induces vascular endothelial dysfunction) and infections have emerged. In fact, the century-old 'infectious' hypothesis of atherosclerosis has implicated a number of micro-organisms that may act as contributing inflammatory stimuli. Although cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae are the three micro-organisms most extensively studied, this review will focus on C. pneumoniae. Collaborative efforts from many disciplines have resulted in the accumulation of evidence from seroepidemiological, pathological, animal model, immunological and antibiotic intervention studies, linking C. pneumoniae with atherosclerosis. Seroepidemiological observations provide circumstantial evidence, which is weak in most prospective studies. Pathological studies have demonstrated the preferential existence of C. pneumoniae in atherosclerotic plaque tissues, while animal model experiments have shown the induction of atherosclerosis by C. pneumoniae. Finally, immunological processes whereby C. pneumoniae could participate in key atherogenic and atherothrombotic events have also been identified. Although benefits of the secondary prevention of atherosclerosis have been demonstrated in some antibiotic intervention studies, a number of negative studies have also emerged. The results of the ongoing large prospective human antibiotic intervention trials may help to finally establish if there is a causal link between C. pneumoniae infection and atherosclerosis.

Animals↗
PubMed2002

Restoration of naive cell repertoire in the appropriate cytokine milieu: a model for preventing cancer relapses.

Tumour immunology has used the paradigm of infections to combat cancer. T cells have been found to have a major role in immunosurveillance against malignant cells. However, with few exceptions like donor leukocyte infusions for relapsed chronic myeloid leukaemia post-allogeneic stem cell transplant, immunological therapies have not yet found wide application in the control of most human cancers. We attribute this to two immunological problems in cancer patients. Firstly, we hypothesize that among all subsets of T cells it is the repertoire of nai;ve cells that is most important and specific for cancer immunity. Some forms of cancer treatment like chemotherapy often damage this very important cell. Secondly, the effector arm of immune response (T cells) is polarized away from the cancer-protecting type 1 phenotype (TH1 cells and type 1-cytokines) towards the type 2 phenotype. We propose that regeneration of nai;ve T cells (for e.g. by thymic transplants) in a type 1-cytokine milieu could be crucial to the prevention of relapses in patients who achieve complete remissions with conventional therapies.

Cytokines↗
PubMed2002

Generalized lymphadenopathy caused by Trichosporon asahii in a patient with Job's syndrome.

Of the six species of Trichosporon known to cause human infections, T. asahii is the main agent of invasive trichosporonosis. We describe an unusual case of generalized lymphadenopathy due to T, asahii in a 10-year-old boy with Job's syndrome (markedly elevated IgE with eosinophilia). The diagnosis was based on the presence of blastic conidia and hyphal elements breaking into arthroconidia in biopsied tissue of the cervical lymph node and isolation of the causal agent T, asahii in pure culture. The patient responded initially to amphotericin B therapy, but the infection recurred within 4 weeks and did not respond to therapy of liposomal amphotericin B and 5-fluorocytosine for 10 days. The patient left the hospital against medical advice.

Child↗
PubMed2002

In vitro interactions of artemisinin with atovaquone, quinine, and mefloquine against Plasmodium falciparum.

The interactions of artemisinin with atovaquone, quinine, and mefloquine were investigated in three Plasmodium falciparum strains (strains F-32, FCR-3, and K-1) by an in vitro culture assay. The parasites were cultured for 48 h in the presence of different concentrations and proportions of two drugs at a time in a checkerboard design. The response parameters were determined, and the sums of the fractional inhibitory concentrations (sigmaFICs) of the drug combinations were calculated for different degrees of inhibition (50% effective concentration [EC50], EC90, and EC99). Within therapeutically relevant molar ratios (19 to 200), the combination of quinine and artemisinin showed mean sigmaFICs of 1.71 at the EC50, 0.36 at the EC90, and 0.13 at the EC99, indicating increasing synergism. Within the range of molar ratios of 4.3 to 50, the combination of mefloquine and artemisinin yielded mean sigmaFCIs of 0.93, 0.44, and 0.31 at the EC50, EC90, and EC99, respectively, indicating synergism. The atovaquone combination showed additive activity to synergism at atovaquone/artemisinin proportions considered relevant to the in vivo situation, i.e., between 4.3 and 200, with the mean sigmaFICs decreasing from 1.34 at the EC50 to 0.85 and 0.23 at the EC90 and EC99, respectively. Interstrain differences in the degree of drug interaction were seen with the three strains for all combinations. Synergism was most consistent with quinine.

Animals↗
PubMed2002

Bilateral groove sign with penoscrotal elephantiasis.

Lymphogranuloma venereum (LGV) is a sexually transmitted disease of the lymph channels caused by Chlamydia trachomatis. Esthiomene, a rare late manifestation of LGV, is a primary infection affecting the lymphatics of scrotum, penis, or vulva. The male genitalia are affected less commonly by esthiomene, but we report a male patient who presented with inguinal syndrome, penoscrotal elephantiasis, along with enlargement of femoral lymph nodes.

Adult↗
PubMed2002

Oxygen regulation of placental 11 beta-hydroxysteroid dehydrogenase 2: physiological and pathological implications.

Preeclampsia (PE) is a major cause of maternal and perinatal morbidity and mortality. The genesis of PE is related to deficient trophoblast invasion of maternal spiral arteries, which might result in a reduction of placental (PL) oxygen (O(2)). An absence of increased O(2) that normally occurs around the 10-12th wk of gestation results in aberrant expression of genes that might contribute to the pathophysiology of PE. We examined the expression and regulation of PL 11 beta-hydroxysteroid dehydrogenase 2 (11 beta-HSD) in normal pregnancies and in PE. Two types of 11 beta-HSD exist in the placenta, 11 beta-HSD1 and 11 beta-HSD2. 11 beta-HSD2 is thought to protect the fetus from cortisol excess. In PE, both the expression and activity of PL 11 beta-HSD2 were reduced significantly compared with those in age-matched controls. As PE is associated with a reduction of PL O(2), we next investigated whether in normal pregnancy 11 beta-HSD2 expression changes at the time of the increase in O(2). 11 beta-HSD2 was detected as early as 5 wk, with expression limited to the syncytiotrophoblast (ST). At 10-12 wk, this expression increased and was also found in the cytotrophoblast and extravillous trophoblast. These results were substantiated by Western blot. The ability of O(2) to regulate 11 beta-HSD2 was determined both in cultures of villous explant from early gestation and in term trophoblast cells after incubation under 3% or 20% O(2). Villous explants cultured under 20% O(2) showed higher enzyme activity and expression compared with 3% O(2). Term trophoblast cells also exhibited higher enzyme activity at 20% vs. 3% O(2). No change in 11 beta-HSD1 expression was observed in early pregnancy or in PE. This is the first report to suggest that 11 beta-HSD2 is O(2) dependent in first and third trimester placenta during human gestation.

11-beta-Hydroxysteroid Dehydrogenase Type 2↗
PubMed2002

Presence of distinct virtual backbone torsion angles in dipeptide conformers.

Zwitterionic dipeptides have recently been shown to exist in water mainly as nine conformational forms with specific combinations of backbone Psi, omega and Phi torsions, which allows conformer-specific molecular recognition of peptide ligands by proteins. Here, we show that pairs of virtual backbone torsions can also define these nine conformational forms, and that comparing these virtual torsions in dipeptides with those of backbone-modified pseudopeptides offers an improved procedure for evaluating peptidomimetics for therapeutic applications.

Calorimetry↗