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Biomedical subjects

R Singhal

Publications and source records attributed to R Singhal.

At least 19 recordsLinked to original sources
PubMed2006

Coral spleen.

Explore the source record for details and available documents.

Aged↗
PubMed2005

Serum lactate and base deficit as predictors of mortality after ruptured abdominal aortic aneurysm repair.

OBJECTIVE: Whole body hypoperfusion and lower torso ischaemia-reperfusion contribute to post-operative organ dysfunction in patients undergoing repair of ruptured abdominal aortic aneurysm (AAA). Serum lactate and base deficit are markers of tissue ischaemia and are used to assess the adequacy of resuscitation. This study examines the prognostic value of immediate post-operative levels of serum lactate and base deficit in ruptured AAA. METHODS: Thirty patients (24 men and 6 women of median age 74, range 51-85, years) who survived to at least 12h after ruptured AAA repair were studied retrospectively. The relationship between immediate post-operative lactate, base deficit and mortality was determined. RESULTS: Fifteen patients (50%) died, all from organ failure. An elevated lactate (>2.1 mmol/l) and base deficit (<-2 mmol/l) were present in 20 (67%) and 27 (90%) patients, respectively. Lactate (p<0.001) and base deficit (p=0.003) were significantly higher in non-survivors compared with survivors. Lactate (p=0.021) and base deficit levels (p=0.028) were independently significant for predicting mortality and a significant interaction existed between lactate and base deficit levels for predicting mortality (p=0.027). The sensitivity and specificity of lactate > or =4.0 mmol/l was 13 of 15 (87%) and 12 of 15 (80%), respectively, and base deficit < or =-7 mmol/l was 12 of 15 (80%) and 12 of 15 (80%), respectively. The likelihood ratios for a positive result with the defined cut-off values for lactate and base deficit were 4.3 and 4.0, respectively. Lactate > or =4.0 mmol/l and base deficit or =-7 mmol/l were associated with a 4% probability of death. CONCLUSION: These data demonstrate that an immediate post-operative serum lactate > or =4.0 mmol/l and base deficit < or =-7 mmol/l are good predictors of outcome after ruptured AAA repair. The prognostic value of these simple and inexpensive tests require corroboration in a larger prospective study.

Acid-Base Imbalance↗
PubMed2004

Immunogenicity of low-dose and conventional-dose recombinant hepatitis B vaccines in healthy adolescents in India.

INTRODUCTION: The recombinant hepatitis B vaccine, at a conventional dose of 20 microgrammes, is highly effective in a majority of the population. Recent studies have reported that a 10-microgramme dose is as effective as the conventional dose, especially in young adolescents. This study compares the effect of two different doses of recombinant hepatitis B vaccine (Enivac HB) in healthy adolescents. METHODS: Ninety-two adolescents were randomised into two equal groups to receive either 10 microgrammes (group 1) or 20 microgrammes (group 2) of vaccine using the vaccination schedule of 0, one and six months. Blood samples were collected at 30, 60, 90, 180 and 210 days to detect anti-HBs antibodies. At each interval, geometric mean titres were calculated for seroconverted subjects. RESULTS: After the initial doses of the vaccine, greater proportion of subjects receiving the higher dose seroconverted. However, at six months, all subjects who received the low dose seroconverted, as did those who received the conventional dose. Furthermore, there were significant differences in the anti-HBs geometric mean titres for seroconverters at 180 days (218.27 versus 111.43) and 210 days (345.14 versus 133.35). The difference in the overall reactogenicity for the two dose levels was not remarkable, although the higher dose produced more local symptoms. CONCLUSION: 10-microgramme recombinant vaccine can be used in routine immunisation in healthy adolescents. If quick immunisation is needed, as in high-risk groups, the conventional dose should be administered, as it results in earlier seroconversion with higher anti-HBs geometric mean titres.

Adolescent↗
PubMed2000

Analysis of serological evidence of different hepatitis viruses in acute viral hepatitis in prisoners in relation to risk factors.

BACKGROUND & OBJECTIVES: The present study describes an outbreak of acute viral hepatitis in an institutional population (inmates of a prison) with an aim to delineate the etiological agents of this outbreak and to analyse the clinical, biochemical and serological evidence of different hepatitis viruses in relation to risk factors. METHODS: Fifty patients of acute viral hepatitis identified during the outbreak were evaluated on the basis of history, clinical examination, risk factor distribution, biochemical profile and serological markers for hepatitis A-E infection. Adequate epidemiological data were collected from prison administration including housing of prisoners, food and water supply. RESULTS: Of the 50 patients, 35 (70%) had serological evidence of HEV infection. Evidence of HBV infection was found in 17 patients (34%), HAV infection in 2 (4%) and HCV in 8 (16%) patients. While 16 patients (32%) had evidence of multiple viral infections, none of the viral markers could be detected in 8 patients (16%). One or more risk factor(s) could be identified in more than half of the subjects (26/50; 52%). There were 11 patients who gave history of more than one risk factor while 24 (48%) patients had none of the risk factors. INTERPRETATION & CONCLUSIONS: HEV was found to be the major cause of the outbreak and contamination of drinking water supply could be the possible source of infection. This outbreak was seroepidemiologically similar to other outbreaks of hepatitis occurring in the country with HEV being the most common cause. However, there was evidence of multiple viral infections, particularly HBV and HCV in the high-risk predisposed prison population.

Adolescent↗
PubMed1999

GABA(A) receptor subunit messenger RNA expression in the enteric nervous system of the rat: implications for functional diversity of enteric GABA(A) receptors.

GABAergic neurons occur in the myenteric plexus and submucosa and their innervations of the gut, where GABA stimulates motor neurons, and non-neural cells via "central type" GABA(A) receptors. These receptors occur on half of the neurons in the rat intestine. The GABA(A) receptor is a ligand-gated chloride channel constructed from different subunit families (alpha, beta, gamma, delta, epsilon). In rat these exist as subtypes, alpha1-6, beta1-3, gamma1-3 and delta, defining the clinically relevant pharmacological features of GABA(A) receptors. However, the identity, distribution, and abundance of enteric GABA(A) receptor subunits are unknown. To identify and map the regional expression of GABA(A) receptor subunit messenger RNAs in the enteric nervous system, we assayed enteric RNA from the ileum of Sprague-Dawley rats by reverse transcription-polymerase chain reaction for alpha1-6, beta 1-3, gamma1-3, and delta subunit messenger RNAs. Subunit messenger RNA localization, was probed by in situ hybridization. Reverse transcription-polymerase chain reaction analysis of RNA from myenteric and submucosal nerve layers revealed the expression alpha1, alpha3, beta2, beta3, gamma1 and gamma3 subunit messenger RNAs. Little alpha4 and alpha6 and no alpha2, beta1, gamma2 or delta subunit messenger RNA were detected. In situ hybridization revealed that transcripts for alpha1, alpha3, alpha5 and beta2 subunits occur in both myenteric and submucous ganglia. However, beta3 messenger RNA was found only in myenteric plexus. The gamma1 subunit messenger RNA was also restricted to the cells in the myenteric plexus while gamma3 was found in cells of both nerve layers. In this study of the subunit messenger RNA expression profile of GABA(A) receptors within the enteric nerve layers we show an abundant, diverse and widespread distribution that is unique in comparison to the CNS. The distinctive and heterogeneous distribution of enteric GABA(A) subunits may be important in the integration of neural control of gut function.

Animals↗
PubMed1996

Application of spherical and other polymers in capillary zone electrophoresis: separation of antiviral drugs and deoxyribonucleoside phosphates by different principles.

Soluble polymers of linear chains with limited branching and spherical polymers (limit dextrins and sucrose, such as Dextran and Ficoll (Pharmacia Chemicals), yielding lower viscosities, are examined here for the separation of different nucleotides and several anti-AIDS drugs by capillary zone electrophoresis (CZE). The linear polymer forms a network but spherical polymers appear to create a second pseudo-phase. In general, they tend to enhance the solute mobility and reduce peak width; thus, they improve the column efficiency. We observe that the beads of a spherical polymer produce a pseudo-phase even in a very low polymer concentration. The proposed method involving a spherical polymer yields the best separation for twelve deoxyribonucleoside mono-, di- and triphosphates in ca. 10 min. Common anti-AIDS drugs (ddA, ddC, ddI, d4T, AZT) and an AZT metabolite (AZT-glucuronate) are resolved by using conventional micellar electrokinetic capillary chromatography (MEKC). These results not only offer fast and highly sensitive detection techniques for the pharmacokinetics of nucleotides, drugs, and their metabolites, but they also demonstrate an application of the proposed second pseudo-phase involving spherical polymer beads in CZE separations.

Anti-HIV Agents↗
PubMed1992

Correlation between antibodies to mannophosphoinositides & detection of antigen in circulating immune complexes in patients with pulmonary tuberculosis.

Enzyme linked immunosorbent assays were used to detect the concentration of mannophosphoinositides in circulating immune complexes (CICs) and antibodies to these antigens in the sera of patients with pulmonary tuberculosis. Serum samples from 235 tuberculosis patients at various levels of disease progression were analysed. Multiple regression analysis showed a direct correlation between antigen levels in CICs and serum antibodies to mannophosphoinositides.

Antibodies, Bacterial↗
PubMed1991

Purification and characterization of the 180- and 86-kilodalton subunits of the Saccharomyces cerevisiae DNA primase-DNA polymerase protein complex. The 180-kilodalton subunit has both DNA polymerase and 3'----5'-exonuclease activities.

The yeast Saccharomyces cerevisiae catalytic DNA polymerase I 180-kDa subunit and the tightly associated 86-kDa polypeptide have been purified using immunoaffinity chromatography, permitting further characterization of the DNA polymerase activity of the DNA primase-DNA polymerase protein complex. The subunits were purified to apparent homogeneity from separate overproducing yeast strains using monoclonal antibodies specifically recognizing each subunit. When the individual subunits were recombined in vitro a p86p180 physical complex formed spontaneously, as judged by immunoprecipitation of 180-kDa polypeptide and DNA polymerase activity with the anti-86-kDa monoclonal antibody. The 86-kDa subunit stabilized the DNA polymerase activity of the 180-kDa catalytic subunit at 30 degrees C, the physiological temperature. The apparent DNA polymerase processivity of 50-60 nucleotides on poly(dA).oligo(dT)12 or poly(dT).oligo(A)8-12 template-primer was not affected by the presence of the 86-kDa subunit but was reduced by increased Mg2+ concentration. The Km of the catalytic 180-kDa subunit for dATP or DNA primer terminus was unaffected by the presence of the 86-kDa subunit. The isolated 180-kDa polypeptide was sufficient to catalyze all the DNA synthesis that had been observed previously in the DNA primase-DNA polymerase protein complex. The 180-kDa subunit possessed a 3'----5'-exonuclease activity that catalyzed degradation of polynucleotides, but degradation of oligonucleotide substrates of chain lengths up to 50 was not detected. This exonuclease activity was unaffected by the presence of the 86-kDa subunit. Despite the striking physical similarity of the DNA primase-DNA polymerase protein complex in all eukaryotes examined, the data presented here indicate differences in the enzymatic properties detected in preparations of the DNA polymerase subunits isolated from S. cerevisiae as compared with the properties of preparations from Drosophila cells. In particular, the 3'----5'-exonuclease activity associated with the yeast catalytic DNA polymerase subunit was not masked by the 86-kDa subunit.

Animals↗
PubMed1988

An unusual case of pycnodysostosis.

A 6 year old boy with clinical and radiological features of pycnodysostosis is described. In addition to pycnodysostosis he had a myelophthisic type of anaemia suggesting an overlap with osteopetrosis.

Anemia, Myelophthisic↗