Search PubMed⌕ Search

Biomedical subjects

R Gupta

Publications and source records attributed to R Gupta.

At least 487 records · Page 27Linked to original sources
PubMed1996

Fatty acid synthesis by isolated leucoplasts from developing Brassica seeds: role of glycolytic intermediates as the source of carbon and energy.

Fatty acid synthesis from Na [1-14C] acetate in leucoplasts isolated from developing seeds of Brassica campestris was completely dependent on exogenous supply of ATP. None of the intermediates of glycolysis or pentose phosphate pathway tested could replace ATP in the reaction mixture. In absence of exogenously supplied ATP, maximum activity was obtained with glu-6-P (68%) followed by fru-6-P (50%) and PEP (44%), respectively. With other intermediates as energy sources, the activity ranged from 1 to 38%. In complementary experiments (presence of ATP), none of the metabolites gave activity higher than the ATP control activity. Under optimum conditions for fatty acid synthesis from acetate, Brassica leucoplasts readily utilized labelled glucose as the substrate for fatty acid synthesis. Omission of NADH and NADPH individually from the reaction mixtures containing labelled glucose resulted only in 46 and 20% loss in activity, respectively, compared to the corresponding losses of 56 and 50%, when labelled acetate was used as the substrate. Similarly, deletion of ATP from the reaction mixture containing glucose as the substrate decreased the rate of fatty acid synthesis by about 65%, while the corresponding decrease with acetate as the substrate was 96%. Inclusion of 5 mM cold acetate, pyruvate, malate and glu-6-P in the reaction mixture containing glucose as the labelled substrate reduced label incorporation into fatty acids by 38 to 69%, maximum reduction being observed with pyruvate followed by glu-6-P, acetate and malate, respectively. With labelled acetate as the substrate, maximum reduction in label incorporation was obtained with cold glucose (5 mM) followed by glu-6-P, pyruvate and malate, respectively. The study demonstrated the operation of complete glycolytic pathway in Brassica leucoplasts, allowing the plastids to use glucose as a source of carbon, reducing power and energy for fatty acid synthesis.

Acetates↗
PubMed1996

Lifestyle risk factors and coronary heart disease prevalence in Indian men.

To determine prevalence of various lifestyle coronary risk factors and their association with coronary heart disease (CHD) prevalence we studied 3397 Indian men (1982 rural, 1415 urban). A doctor-administered questionnaire, physical examination and electrocardiography was used. CHD was diagnosed by clinical history and electrocardiographic criteria. Lifestyle risk factor prevalence was: illiteracy 1238 (36%), nuclear family 575 (17%), crowded housing (> or = 3 persons/room) 837 (25%), > or = 4 children 881 (26%), smoking 1554 (46%), alcohol intake 592 (17%), non-vegeterian diet intake 835 (25%), high fat intake 1196 (35%), absence of prayer habit 2276 (67%), absent leisure-time physical activity 2832 (83%) and obesity (body-mass index > or = 27 Kg/M2) 265 (8%). In rural as compared to urban men there was a significantly higher prevalence of illiteracy (39% vs 33%), crowded housing (30% vs 17%), smoking (51% vs 39%), alcohol intake (19% vs 15%) and high fat intake (39% vs 29%) (p < 0.01). In urban as compared to rural men the prevalence of nuclear family (28% vs 9%), > or = 4 children (29% vs 24%), non-vegetarian diet intake (35% vs 17%) and sedentary lifestyle (86% vs 81%) was more. CHD prevalence was seen in 152 (4.5%). The prevalence of CHD was significantly more in urban men (urban 6.0% vs rural 3.4%, p < 0.001). Odds ratios (95% confidence intervals) for CHD and lifestyle risk factors showed significant positive associations with nuclear family 1.61 (1.15-2.24), > or = 4 children 2.10 (1.51-2.93), crowded housing 1.48 (1.04-2.10), sedentary lifestyle 1.47 (1.00-2.25) and smoking 1.30 (1.00-1.80), and inverse association with high fat intake 0.42 (0.28-0.63), and not with illiteracy 0.99 (0.70-1.39), alcohol intake 0.84 (0.53-1.32), non-vegeterian diet 0.89 (0.61-1.29), absent prayer habit 1.26 (0.88-1.81), or obesity 1.42 (0.83-1.32).

Adult↗
PubMed1996

Prevalence of asymptomatic electrocardiographic abnormalities in a rural population.

To determine the prevalence of various electrocardiographic (ECG) abnormalities among asymptomatic individuals in a rural population of India we performed a 12-lead ECG during a comprehensive cardiovascular survey in three randomly selected villages in Rajasthan. Twenty four of 3148 individuals with a past diagnosis or symptoms suggestive of coronary heart disease (CHD) were excluded. ECG of 3124 persons (males 1965, females 1159) were analysed and classified according to the WHO-Minnesota Code. The prevalence rate/1000 of Q-waves was 8.6 (males 8.7, females 8.6) and ST-T wave changes was 17.0 (males 12.7, females 24.2). An age-related increase in prevalence of Q-waves was seen (X2 for trend p < 0.01). The Q wave prevalence was similar among males and females but ST-T changes were more frequent in females (p = 0.0016). Other prevalent findings were left ventricular hypertrophy in 8.3, right or left bundle branch block pattern in 18.6, left or right axis deviation in 10.6, atrioventricular conduction defects in 10.2 and ventricular arrhythmia in 1.3/1000 population.

Adult↗
PubMed1996

Correlation of rainfall with upsurge of malaria in Rajasthan.

There has been a recent increase in malaria cases in Rajasthan. To determine whether environmental factors such as rainfall explain the upsurge we performed a study correlating the amount and duration of rainfall with annual malaria incidence. Data of annual incidence of malaria and Plasmodium falciparum malaria, annual and monthly rainfall and cultivated land area in Rajasthan were acquired from government sources from 1980 to 1994. The mean annual malaria incidence was 277 +/- 90 cases/100,000 population and falciparum malaria 70 +/- 43 cases/100,000 population per year. There was rising trend in total malaria and specially falciparum malaria incidence (r = 0.50, p = 0.057) over these years. The mean annual rainfall in the state was 541 +/- 144 mm/year and the mean cultivated land area was 15.5 +/- 1.2 million hectares/year with a significant interrelationship (r = 0.66, p = 0.008). The overall malaria incidence showed a moderate correlation (r = 0.48, p = 0.069) with annual rainfall while the incidence of falciparum malaria showed a significant correlation (r = 0.61, p = 0.016). Rainfall in the months of June, July and August did not show any significant correlation with annual malaria incidence. Rainfall in the month of September showed significant correlation with the incidence of overall malaria (r = 0.62, p = 0.015) as well as falciparum malaria (r = 0.71, p = 0.003). This relationship remained significant after adjustment for years of study and cultivated land-area (standardised regression coefficients: total malaria (b = 0.72, p = 0.060), falciparum malaria (b = 0.64, p = 0.059). There is a positive correlation of rainfall with incidence of malaria. Prolonged rains as suggested by rainfall extending to the month of September are associated with significantly higher incidence of total as well as falciparum malaria.

Environmental Exposure↗
PubMed1995

The pleckstrin homology domain of phospholipase C-delta 1 binds with high affinity to phosphatidylinositol 4,5-bisphosphate in bilayer membranes.

The pleckstrin homology (PH) domain of phospholipase C-delta 1 (PLC-delta 1) binds to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in phospholipid membranes with an affinity (Ka approximately 10(6) M-1) and specificity comparable to those of the native enzyme. PLC-delta 1 and its PH domain also bind inositol 1,4,5-trisphosphate, the polar head group of PI(4,5)P2, with comparable affinity and approximately 1:1 stoichiometry. A peptide corresponding to amino acids 30-43 of the PLC-delta 1 PH domain contains several basic residues predicted to bind PI(4,5)P2, but binds weakly and with little specificity for PI(4,5)P2; hence the tertiary structure of the isolated PH domain is required for high affinity PI(4,5)P2 binding. Our PI-(4,5)P2 binding results support the hypothesis that the intact PH domain, serving as a specific tether, directs PLC-delta 1 to membranes enriched in PI(4,5)P2 and permits the active site, located elsewhere in the protein, to hydrolyze multiple substrate molecules before this enzyme dissociates from the membrane surface.

Amino Acid Sequence↗
PubMed1995

Gene cloning, expression, and characterization of the Sac7 proteins from the hyperthermophile Sulfolobus acidocaldarius.

The genes for two Sac7 DNA-binding proteins, Sac7d and Sac7e, from the extremely thermophilic archaeon Sulfolobus acidocaldarius have been cloned into Escherichia coli and sequenced. The sac7d and sac7e open reading frames encode 66 amino acid (7608 Da) and 65 amino acid (7469 Da) proteins, respectively. Southern blots indicate that these are the only two Sac7 protein genes in S. acidocaldarius, each present as a single copy. Sac7a, b, and c proteins appear to be carboxy-terminal modified Sac7d species. The transcription initiation and termination regions of the sac7d and sac7e genes have been identified along with the promoter elements. Potential ribosome binding sites have been identified downstream of the initiator codons. The sac7d gene has been expressed in E. coli, and various physical properties of the recombinant protein have been compared with those of native Sac7. The UV absorbance spectra and extinction coefficients, the fluorescence excitation and emission spectra, the circular dichroism, and the two-dimensional double-quantum filtered 1H NMR spectra of the native and recombinant species are essentially identical, indicating essentially identical local and global folds. The recombinant and native proteins bind and stabilize double-stranded DNA with a site size of 3.5 base pairs and an intrinsic binding constant of 2 x 10(7) M-1 for poly[dGdC].poly[dGdC] in 0.01 M KH2PO4 at pH 7.0. The availability of the recombinant protein permits a direct comparison of the thermal stabilities of the methylated and unmethylated forms of the protein. Differential scanning calorimetry demonstrates that the native protein is extremely thermostable and unfolds reversibly at pH 6.0 with a Tm of approximately 100 degrees C, while the recombinant protein unfolds at 92.7 degrees C.

Amino Acid Sequence↗
PubMed1995

Effect of growth environment on the stability of a recombinant shuttle plasmid, pCPPS-31, in Escherichia coli.

The effect of environmental growth conditions on the segregational stability of a recombinant Escherichia coli-Bacillus subtilis shuttle plasmid pCPPS-31 which expresses carboxymethyl cellulase (CMCase) and contains the neomycin resistance gene (Ner), was studied in E. coli DH5 alpha. The stability increased with the decrease in medium complexity. Lowering culture temperatures had a negative effect on stability. Stability was maximum at 100 rpm and a medium/flask volume ratio of 1:10. A pH range of 5-8 had no significant effect on stability. The recombination (rec) and gyrase (gyr) backgrounds of E. coli hosts had no apparent effect on plasmid stability. The plasmid was structurally stable under all circumstances.

Aerobiosis↗
PubMed1995

Viscoelastic properties of human tracheobronchial mucin in aqueous solution.

Human tracheobronchial mucin isolated from cystic fibrosis patients (CF HTBM) was purified using a combination of gel filtration and density gradient centrifugation. The resulting mucin was fractionated to reduce polydispersity and to facilitate studies of the molecular weight dependence of mucin viscoelasticity in concentrated solution. The viscoelastic properties of CF HTBM were examined in distilled water, 0.1M salt solutions and chaotropic solvents. In controlled strain experiments (strain > or = 5%) with increasing mucin concentration, a crossover from sol to gel behavior is observed. The gel strength, as measured by the magnitude of the storage modulus at comparable mucin concentrations, is greatest for distilled water, intermediate for 0.1M NaCl, and lowest for 6M GdnHCl. In distilled water, high molecular weight mucin undergoes a sol-gel transition at approximately 12 mg/mL, and shows evidence of a plateau modulus at higher concentrations. The storage and loss moduli of concentrated high molecular weight fractions in 6M GdnHCl exhibit a power law dependence on frequency typical of weak gels near the sol-gel transition at 20 mg/mL. Similar rheology is observed in 0.1M NaCl and 0.091M NaCl/3 mM CaCl2, but with evidence for additional weak associations at low frequency. The power law exponent in these systems is 0.70 +/- 0.02, in good agreement with prediction for networks formed by a percolation mechanism. Low molecular weight fractions in these solvents exhibit a fluid-like viscoelastic response. However, low molecular weight mucin in distilled water shows a strain-dependent increase in elasticity at low frequency indicative of weak intermolecular associations. Comparison of the rheological behavior of CF HTBM with our earlier studies of ovine submaxillary mucin lends support to the idea that carbohydrate side-chain interactions are important in the gelation mechanism of mucins.

Bronchi↗
PubMed1995

Serial transcranial Doppler study in meningitis.

Serial transcranial doppler studies were carried out in 12 patients, who developed meningitis during their hospital stay. Blood flow velocities in large basal vessels of the anterior circle of Willis were correlated with CSF pleocytosis and CSF sugar values. Mean blood flow velocities were found to be directly proportional to the CSF white blood cell (WBC) count and were inversely proportional to the CSF sugar values. Blood flow velocities were higher when CSF WBC count was raised. With only one exception these velocities decreased progressively with a fall in the CSF WBC count. At the time of meningitis there occurred a reduction in CSF sugar values and the blood flow velocities were significantly higher. With increase in CSF sugar values there occurred a gradual fall in the blood flow velocities.

Adolescent↗
PubMed1995

Constituents of human urine alter siderophore production of Escherichia coli.

Four uroisolates and four faecal isolates of Escherichia coli were randomly selected for studying the siderophore production in an iron-deficient, chemically defined, medium. Glucose, lactose, urea and creatinine were added individually, as well as in combination, to estimate their influence on siderophore production. No difference in siderophore production was observed between stool and urinary isolates of E. coli. Alterations in phenolate production were observed to be constituent-dependent while a uniformly significant increase in hydroxamate production (p < 0.05) was recorded after addition of the constituents, either each individually or in combination.

Creatinine↗
PubMed1995

Percutaneous catheter drainage of amebic liver abscesses with and without intrahepatic biliary communication: a comparative study.

Influence of communication with the intrahepatic biliary system on the clinical picture of amebic liver abscesses in 33 consecutive patients resistant to medical therapy, and their response to percutaneous catheter drainage was evaluated. Abscess-biliary communication was found in 27% of the sample. Patients with abscesses communicating with the biliary tree presented more frequently with jaundice (67% vs. 0%, P < 0.005), with a longer duration of illness (median 20 vs. 12 days, P < 0.001), had larger lesions (median 600 vs. 320 ml, P < 0.001) and required catheter drainage for longer periods (median 17 vs. 6.5 days, P < 0.000001). However the presence of a biliary communication did not materially affect the cure rate with catheter drainage (89% vs 100%, P > or = 0.05). In conclusion, an abscess-biliary communication is not uncommon in refractory amebic liver abscesses, and can be clinically detected by the presence of jaundice. Though a prolonged period of drainage may be necessary in the presence of this complication, catheter drainage can be expected to result in cure.

Adult↗
PubMed1995

Stress fracture of the hyoid bone caused by induced vomiting.

Fracture of the hyoid bone is a well-documented but rare consequence of certain types of trauma to the neck and lower face that may result in significant complications. We report a case of hyoid bone fracture, caused by induced vomiting, that resolved without complications and discuss the mechanism of injury and its complications, as well as associated injuries.

Adult↗
PubMed1995

Hip arthroplasty in patients with chronic renal failure.

Patients with chronic renal failure who underwent total hip arthroplasty were retrospectively evaluated. Thirty hips in patients with renal transplants and 16 hips in patients on chronic renal dialysis were reviewed. The average follow-up period was 54 months. The renal transplant patients exhibited generally satisfactory results. Their postoperative course was comparable to that of patients with avascular necrosis undergoing hip reconstruction without underlying renal disease. However, patients undergoing hip arthroplasty while on chronic renal dialysis had poor results (81%), including a deep infection rate of 19%. It was concluded that total hip arthroplasty be reserved for patients who are expecting a renal transplant or preferably those who have already received a successful transplant.

Adult↗
PubMed1995

The use of texture analysis to delineate suspicious masses in mammography.

In mammography, national breast screening programmes have lead to a large increase in the number of mammograms needing to be studied by radiologists. Lesion indicators can be pointlike as in microcalcifications or extended as in stellate (spiculate) lesions or regular masses. Texture analysis has been proposed as a promising method for studying radiographic images in relation to the quantitation of extended objects. Filters have been designed, which may be used to segment or classify an image using textural features, and these have been reported as being of value in automatic mammographic glandular tissue classification. The work reported here suggests the incorporation of additional steps of image processing in an attempt to improve the performance of these filters in the quantitation of lesions. By deriving approximate outlines, which are used to identify suspicious regions, the investigation illustrates the properties of one of the filters. After applying the method to a small prediagnosed database of stellate lesions and regular masses, the results show that the filter is able to outline the malignant masses in all cases presented. The erroneous areas extracted are small for the initial part of the work, which deals with 256 x 256 pixel image extracts, though slightly larger in some cases when the whole mammogram is considered. Simple methods for the removal of these artefacts are proposed. For each non-suspicious case studied, the sum of any false positive areas is statistically insignificant when compared with the regions correctly outlined in the prediagnosed instances.

Biometry↗