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Biomedical subjects

Arvind Gupta

Publications and source records attributed to Arvind Gupta.

10 recordsLinked to original sources
PubMed2007

Case reports of three patients showing optic nerve head melanocytoma and systemic hypertension.

PURPOSE: To report the association of optic disk melanocytoma with systemic hypertension. CASES: Ocular examination of 3 asymptomatic hypertensive patients revealed a pigmented lesion over the optic disk. After clinical examination and radiological evaluation a diagnosis of optic disk melanocytoma was made. One patient had a mild decrease in visual acuity associated with an increase in size of the lesion during the follow-up. Systemic evaluation revealed increased urinary vanillylmandelic acid in all the patients. MRI showed diffuse adrenal hyperplasia while a (131)I-MIBG scan showed increased uptake in 1 case. CONCLUSIONS: Optic disk melanocytoma is a benign tumor though the lesion may increase in size with the resultant decrease in visual acuity over few years. It may be associated with systemic hypertension secondary to increased levels of catecholamines in the body, which is related to the common neural crest origin of melanocytes, adrenal medullary cells and chromaffin cells.

Adult↗
PubMed2006

Composite thermal conductivity in a large heterogeneous porous methane hydrate sample.

By employing inverse modeling to analyze the laboratory data, we determined the composite thermal conductivity (k(theta), W/m/K) of a porous methane hydrate sample ranged between 0.25 and 0.58 W/m/K as a function of density. The calculated composite thermal diffusivities of porous hydrate sample ranged between 2.59 x 10(-7) m(2)/s and 3.71 x 10(-7) m(2)/s. The laboratory study involved a large heterogeneous sample (composed of hydrate, water, and methane gas). The measurements were conducted isobarically at 4.98 MPa over a temperature range of 277.3-279.1 K. Pressure and temperature were monitored at multiple locations in the sample. X-ray computed tomography (CT) was used to visualize and quantify the density changes that occurred during hydrate formation from granular ice. CT images showed that methane hydrate formed from granular ice was heterogeneous and provided an estimate of the sample density variation in the radial direction. This facilitated quantifying the density effect on composite thermal conductivity. This study showed that the sample heterogeneity should be considered in thermal conductivity measurements of hydrate systems. Mixing models (i.e., arithmetic, harmonic, geometric mean, and square root models) were compared to the estimated composite thermal conductivity determined by inverse modeling. The results of the arithmetic mean model showed the best agreement with the estimated composite thermal conductivity.

Journal Article↗
PubMed2006

Nitazoxanide for the treatment of Clostridium difficile colitis.

BACKGROUND: Clostridium difficile colitis has increased in incidence and severity, and treatment failure with metronidazole therapy has increasingly been documented. It is uncertain whether treatment with vancomycin is more effective than treatment with metronidazole, but concern over the emergence of vancomycin resistance has motivated the search for alternative therapy. Nitazoxanide, a nitrothiazolide, blocks anaerobic metabolism of eukaryocyes and effectively treats intestinal infestation due to Cryptosporidium or Giardia species. At low concentrations, this compound inhibits C. difficile in vitro. METHODS: We designed a prospective, randomized, double-blind study to compare nitazoxanide to metronidazole in treating hospitalized patients with C. difficile colitis. RESULTS: Thirty-four patients received metronidazole at a dosage of 250 mg 4 times per day for 10 days, 40 patients received nitazoxanide at a dosage of 500 mg 2 times per day for 7 days, and 36 patients received nitazoxanide at a dosage of 500 mg 2 times per day for 10 days. After 7 days of treatment, 28 (82.4%) of 34 patients had responded to metronidazole therapy, compared with 68 (89.5%) of 76 who had received nitazoxanide therapy (difference, 7.1%; 95% confidence interval, -7.1% to 25.5%). Thirty-one days after beginning treatment, sustained responses were observed in 19 (57.6%) of 33 patients who had received metronidazole therapy for 10 days, compared with 25 (65.8%) of 38 who had received nitazoxanide for 7 days and 26 (74.3%) of 35 who had received nitazoxanide for 10 days (P = .34). CONCLUSION: Nitazoxanide is at least as effective as metronidazole in treating C. difficile colitis.

Aged↗
PubMed2006

Chronic renal insufficiency among Asian Indians with type 2 diabetes: I. Role of RAAS gene polymorphisms.

BACKGROUND: Renal failure in diabetes is mediated by multiple pathways. Experimental and clinical evidences suggest that renin-angiotensin-aldosterone system (RAAS) has a crucial role in diabetic kidney disease. A relationship between the RAAS genotypes and chronic renal insufficiency (CRI) among type 2 diabetes subjects has therefore been speculated. We investigated the contribution of selected RAAS gene polymorphisms to CRI among type 2 diabetic Asian Indian subjects. METHODS: Twelve single nucleotide polymorphisms (SNPs) from six genes namely-renin (REN), angiotensinogen (ATG), angiotensin converting enzyme I (ACE), angiotensin II type 1 receptor (AT1) and aldosterone synthase (CYP11B2) gene from the RAAS pathway and one from chymase pathway were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and tested for their association with diabetic CRI using a case-control approach. Successive cases presenting to study centres with type 2 diabetes of > or =2 years duration and moderate CRI diagnosed by serum creatinine > or =3 mg/dl after exclusion of non-diabetic causes of CRI (n = 196) were compared with diabetes subjects with no evidence of renal disease (n = 225). Logistic regression analysis was carried out to correlate various clinical parameters with genotypes, and to study pair wise interactions between SNPs of different genes. RESULTS: Of the 12 SNPs genotyped, Glu53Stop in AGT and A>T (-777) in AT1 genes, were monomorphic and not included for further analysis. We observed a highly significant association of Met235Thr SNP in angiotensinogen gene with CRI (O.R. 2.68, 95%CI: 2.01-3.57 for Thr allele, O.R. 2.94, 95%CI: 1.88-4.59 for Thr/Thr genotype and O.R. 2.68, 95%CI: 1.97-3.64 for ACC haplotype). A significant allelic and genotypic association of T>C (-344) SNP in aldosterone synthase gene (O.R. 1.57, 95%CI: 1.16-2.14 and O.R. 1.81, 95%CI: 1.21-2.71 respectively), and genotypic association of GA genotype of G>A (-1903) in chymase gene (O.R. 2.06, 95%CI: 1.34-3.17) were also observed. CONCLUSION: SNPs Met235Thr in angiotensinogen, T>C (-344) in aldosterone synthase, and G>A (-1903) in chymase genes are significantly associated with diabetic chronic renal insufficiency in Indian patients and warrant replication in larger sample sets. Use of such markers for prediction of susceptibility to diabetes specific renal disease in the ethnically Indian population appears promising.

Asian People↗
PubMed2005

Structure-approximating inverse protein folding problem in the 2D HP model.

The inverse protein folding problem is that of designing an amino acid sequence which has a particular native protein fold. This problem arises in drug design where a particular structure is necessary to ensure proper protein-protein interactions. In this paper, we show that in the 2D HP model of Dill it is possible to solve this problem for a broad class of structures. These structures can be used to closely approximate any given structure. One of the most important properties of a good protein (in drug design) is its stability--the aptitude not to fold simultaneously into other structures. We show that for a number of basic structures, our sequences have a unique fold.

Computational Biology↗
PubMed2004

Prevalence of metabolic syndrome in an Indian urban population.

OBJECTIVES: To determine prevalence of the metabolic syndrome using United States Adult Treatment Panel-3 (ATP-3) guidelines in an urban Indian population. METHODS: Randomly selected adults >20 years were studied using stratified sampling. Target study sample was 1800 with population proportionate distribution (men 960, women 840). Evaluation of anthropometric variables, blood pressure, fasting blood glucose and lipids was performed. Subjects (1123; response 62.4%) were examined, fasting blood samples were available in 1091 (532 men, 559 women) and analysed for prevalence of metabolic syndrome. Atherosclerosis risk factors were determined using the current guidelines. Metabolic syndrome was diagnosed when any three of the following were present: central obesity, raised triglycerides >/=150 mg/dl (>/=1.7 mmol/l), low high-density lipoprotein (HDL) cholesterol, blood pressure >/=130/>/=85 mm Hg, and diabetes or fasting glucose >110 mg/dl (>6.1 mmol/l). Intergroup comparisons were performed using t-test or chi-square test. RESULTS: Metabolic syndrome was present in 345 (31.6%) subjects; prevalence was 122 (22.9%) in men and 223 (39.9%) in women (p<0.001); the age-adjusted prevalence was 24.9%, 18.4% in men and 30.9% in women. There was a significant age-related increase in its prevalence (Mantel-Haenzel chi(2) for trend p<0.05). Prevalence of components of metabolic syndrome in men and women was: central obesity (waist, men >102 cm, women >88 cm) in 116 (25.6%) and 246 (44.0%); low HDL cholesterol (men<40 mg/dl, <1.0 mmol/l), women<50 mg/dl, <1.3 mmol/l) in 292 (54.9%) and 504 (90.2%); high triglycerides >/=150 mg/dl (>/=1.7 mmol/l) in 172 (32.3%) and 160 (28.6%); and impaired fasting glucose or diabetes in 90 (16.9%) and 90 (16.1%). The prevalence of physical inactivity, hypertension, hypercholesterolemia (>/=200 mg/dl, >/=5.2 mmol/l) and high LDL cholesterol (>/=130 mg/dl, >/=3.4 mmol/l) was greater in the metabolic syndrome group in both men and women (p<0.05). CONCLUSIONS: There is a high prevalence of metabolic syndrome in an urban Indian population. Focus of cardiovascular prevention should be at this high-risk group.

Adult↗
PubMed2004

Inverse protein folding in 2D HP mode (extended abstract).

The inverse protein folding problem is that of designing an amino acid sequence which has a particular native protein fold. This problem arises in drug design where a particular structure is necessary to ensure proper protein-protein interactions. In this paper we show that in the 2D HP model of Dill it is possible to solve this problem for a broad class of structures. These structures can be used to closely approximate any given structure. One of the most important properties of a good protein is its stability -- the aptitude not to fold simultanously into other structures. We show that for a number of basic structures, our sequences have a unique fold.

Algorithms↗
PubMed2003

Prevalence of diabetes, impaired fasting glucose and insulin resistance syndrome in an urban Indian population.

OBJECTIVE: Epidemiological study among urban subjects in western India to determine prevalence of diabetes, insulin resistance syndrome (IRS) and their risk factors. METHODS: Randomly selected adults > or =20 years were studied using stratified sampling. Target sample was 1,800 (men 960, women 840). 1123 subjects (response 62.4%) were evaluated and blood samples were available in 532 men and 559 women (n=1091, 60.6%). Measurement of anthropometric variables, blood pressure, fasting blood glucose and lipids was performed. Atherosclerosis risk factors were determined using current guidelines. Diabetes was diagnosed when the subject was a known diabetic or fasting blood glucose was > or =126 mg/dl, impaired fasting glucose (IFG) diagnosed when fasting glucose was 110-125 mg/dl. IRS was diagnosed when any three of-IFG, high triglycerides >150 mg/dl, low HDL cholesterol (men<40 mg/dl, women<50 mg/dl), central obesity (men>102 cm, women>88 cm), or high normal blood pressure (>130/>85 mmHg) or hypertension-were present. RESULTS: Diabetes was present in 70 men (13.2%) and 64 women (11.5%). Age-adjusted prevalence of diabetes was 9.3% in men (95% confidence intervals (CI) 6.7-11.8), 8.1% in women (CI 5.8-10.4) and 8.6% overall (CI 6.9-10.3). IFG was in 28 men (5.3%) and 29 women (5.2%). IRS was present in 52 men (9.8%) and 114 women (20.4%) with age-adjusted prevalence of 7.9% in men (CI 6.7-9.1) and 17.5% in women (CI 14.4-20.6) with an overall prevalence of 12.8% (CI 10.8-14.8). Other metabolic abnormalities of IRS in men and women were high triglycerides in 32.1 and 28.6%, low HDL cholesterol in 54.9 and 90.2%; central obesity in 21.8 and 44.0%, and high normal blood pressure or hypertension in 35.5 and 32.4%. IFG subjects had similar atherosclerosis risk factor profile as normal subjects while those with IRS and diabetes had significantly greater prevalence of obesity, central obesity, hypertension, high triglycerides and low HDL (P<0.01). CONCLUSIONS: There is s significant prevalence of diabetes and IRS in this urban Indian population. Subjects with diabetes as well as IRS have greater prevalence of obesity, central obesity, hypertension, hypertriglyceridemia and low HDL as compared with normal subjects.

Adult↗
PubMed2003

Insulin levels in low birth weight neonates.

BACKGROUND & OBJECTIVES: Foetal undernutrition may have important role in adult insulin resistance and diabetes but insulin kinetics in very early life has not been well studied. The present study was undertaken to determine insulin levels in low birth weight neonates and compare with the levels in normal weight and high birth weight neonates. METHODS: Ten 7 day old children each of low birth weight (< 2500 g, Group 1), normal birth weight (2500-3500 g, Group 2) and high birth weight (> 3500 g, Group 3) selected successively over a period of one month were studied. All children were normally delivered at full term and were not suffering from any major illness. Detailed anthropometry was performed, a 6 h fasting blood sample was obtained for blood glucose, lipids, insulin and C-peptide estimation; 60 min after an intravenous glucose load a second sample was obtained for glucose and insulin. Insulin resistance was calculated using the homeostasis model assessment (HOMA). RESULTS: Levels of total cholesterol, triglycerides, low density and high density lipoprotein cholesterol and glucose were not significantly different in the three groups. Mean fasting and post-glucose load insulin levels (microU/ml) were 2.78 +/- 2.23 and 3.28 +/- 2.04 in Group 1, 1.67 +/- 1.20 and 2.60 +/- 2.32 in Group 2 and 3.37 +/- 2.08 and 4.40 +/- 3.05 in Group 3 and fasting C-peptide levels (microg/ml) were 0.296 +/- 0.22, 0.208 +/- 0.09 and 0.327 +/- 0.23 respectively. There was no inter-group difference in insulin-glucose ratio, insulin levels adjusted for ponderal index and HOMA indices. A significant inverse quadratic correlation (U-shaped curve) of body weight with insulin (fasting and post-glucose) and C-peptide levels was observed (P < 0.05). INTERPRETATION & CONCLUSION: Both low and high birth weight term neonates have high fasting and post-glucose insulin levels. This U-shaped trend suggests influence of foetal undernutrition (environmental) as well as genetic factors in these children.

Blood Glucose↗