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Rajeev Gupta

Publications and source records attributed to Rajeev Gupta.

48 records · Page 3Linked to original sources
PubMed2002

Isolation of monomeric Mn(III/II)-H and Mn(III)-complexes from water: evaluation of O-H bond dissociation energies.

The syntheses and properties of the monomeric [MnIII/IIH31(OH)]-/2- and [MnIIIH31(O)]2- complexes are reported, where [H31]3- is the tripodal ligand tris[(N'-tert-butylureaylato)-N-ethyl)]aminato. Isotope-labeling studies with H218O confirmed that water is the source of the terminal oxo and oxygen in the hydroxo ligand. The molecular structures of the [MnIIH31(OH)]2- and [MnIIIH31(O)]2- complexes were determined by X-ray diffraction methods and show that each complex has trigonal bipyramidal coordination geometry. The MnIII-O distance in [MnIIIH31(O)]2- is 1.771(4) A, which is lengthened to 2.059(2) A in [MnIIH31(OH)]2-. Structural studies also show that [H31]3- provides a hydrogen-bond cavity that surrounds the MnIII-O(H) units. Using a thermodynamic approach, which requires pKa and redox potentials, bond dissociation energies of 77(4) and 110(4) kcal/mol were calculated for [MnIIH31(O-H)]2- and [MnIIIH31(O-H)]-, respectively. The calculated value of 77 kcal/mol for the [MnIIH31(O-H)]2- complex is supported by the ability of [MnIIIH31(O)]2- complex to cleave C-H bonds with bond energies of <80 kcal/mol.

Electrochemistry↗
PubMed2002

Transcriptional profiling reveals novel interactions between wounding, pathogen, abiotic stress, and hormonal responses in Arabidopsis.

Mechanical wounding not only damages plant tissues, but also provides pathways for pathogen invasion. To understand plant responses to wounding at a genomic level, we have surveyed the transcriptional response of 8,200 genes in Arabidopsis plants. Approximately 8% of these genes were altered by wounding at steady-state mRNA levels. Studies of expression patterns of these genes provide new information on the interactions between wounding and other signals, including pathogen attack, abiotic stress factors, and plant hormones. For example, a number of wound-responsive genes encode proteins involved in pathogen response. These include signaling molecules for the pathogen resistance pathway and enzymes required for cell wall modification and secondary metabolism. Many osmotic stress- and heat shock-regulated genes were highly responsive to wounding. Although a number of genes involved in ethylene, jasmonic acid, and abscisic acid pathways were activated, many in auxin responses were suppressed by wounding. These results further dissected the nature of mechanical wounding as a stress signal and identified new genes that may play a role in wounding and other signal transduction pathways.

Abscisic Acid↗
PubMed2002

A tumor suppressor homolog, AtPTEN1, is essential for pollen development in Arabidopsis.

Although it is well known that Tyr phosphatases play a critical role in signal transduction in animal cells, little is understood of the functional significance of Tyr phosphatases in higher plants. Here, we describe the functional analysis of an Arabidopsis gene (AtPTEN1) that encodes a Tyr phosphatase closely related to PTEN, a tumor suppressor in animals. The recombinant AtPTEN1 protein, like its homologs in animals, is an active phosphatase that dephosphorylates phosphotyrosine and phosphatidylinositol substrates. RNA gel blot analysis and examination of promoter-reporter constructs in transgenic Arabidopsis plants revealed that the AtPTEN1 gene is expressed exclusively in pollen grains during the late stage of development. Suppression of AtPTEN1 gene expression by RNA interference caused pollen cell death after mitosis. We conclude that AtPTEN1 is a pollen-specific phosphatase and is essential for pollen development.

Amino Acid Sequence↗
PubMed2002

Cytogenetic and molecular genetic abnormalities in systemic mastocytosis.

Clonal cytogenetic abnormalities similar to those observed in other haematological neoplasms are demonstrable in a proportion of patients with systemic mastocytosis and in a smaller proportion of adults with urticaria pigmentosa without apparent systemic disease. These clonal abnormalities are not likely to represent the primary event in mast cell neoplasms. Although no recurrent cytogenetic abnormalities specific for mastocytosis have yet been recognized, the majority of cases display one of several mutations in c-KIT, the gene encoding the receptor for stem cell factor. That most commonly observed is the Asp816Val mutation, which permits proliferation independent of growth factors. c-KIT mutations may play a significant role in the biology of mast cell malignancies, although other mutations may be needed for a malignant phenotype.

Adult↗
PubMed2002

Hindu-Muslim differences in the prevalence of coronary heart disease and risk factors.

Differences in coronary risk factors and coronary heart disease (CHD) prevalence between the Hindus and the Muslims have not been adequately studied. This study aims to determine the prevalence of certain socio-economic and biological coronary risk factors in urban communities and to compare the findings found in the Hindus and the Muslims. The study employed a cross-sectional survey design and stratified random sampling technique consisting of 1,415 males and 797 females. Among males there were 1,092 Hindus (77.2%) and 272 Muslims (19.2%) while in females there were 685 Hindus (85.9%) and 91 Muslims (11.4%). Prevalence of illiteracy and sedentary lifestyle were significantly more in Muslims (p<0.05). Smoking or tobacco use in males was similar but in females it was more in the Hindus. Self-reported diabetes was found in 1.4% Hindu males and in 1.2% Hindu females. No Muslim reported diabetes. Hindu males were significantly taller than Muslims (163.9 +/- 8.3 versus 160.9 +/- 8.9 cm; p < 0.001). In both males and females there was no significant difference in body mass index and obesity. In Hindu males the diastolic BP was significantly greater than in Muslims (81.2 +/- 9.2 versus 79.0 +/- 8.6 mm Hg; p < 0.001); prevalence of hypertension (30.5% versus 25.7%) was also significantly more (p = 0.048). In Hindu females the mean systolic BP was significantly more and there was also difference in hypertension prevalence (35.2% versus 25.3%). CHD prevalence was significantly greater in Hindu males as compared to the Muslims when determined by the presence of either ECG changes alone (4.3% versus 0.7%; p = 0.008) or ECG changes combined with clinical history (7.1% versus 1.8%; p = 0.002). A similar, though not significant, trend was seen in females (ECG changes: 8.9% versus 6.6%, clinical and ECG changes: 10.4% versus 6.6%). The prevalence of CHD is significantly more in Hindu males as compared to the Muslims and is associated with a greater prevalence of diabetes and hypertension.

Adult↗
PubMedDate not supplied

Prevalence of coronary heart disease and risk factors in an urban Indian population: Jaipur Heart Watch-2.

BACKGROUND: The prevalence of risk factors for coronary heart disease has been inadequately studied in India. A repeat cross-sectional survey was carried out to evaluate the changes in the major coronary risk factors in the urban population of Jaipur previously studied in the early 1990s. METHODS AND RESULTS: Randomly selected adults > or =20 years of age were studied using stratified sampling. The target study sample was 1800 with a population proportionate gender distribution (males 960, females 840). Coronary risk factors, anthropometric variables, blood pressure, ECG, fasting blood glucose and lipids were evaluated. A total of 1123 subjects (62.4%) (males 550, females 573) were examined. Fasting blood samples were available in 523 males and 559 females. Overall coronary heart diesase prevalence, diagnosed by history or ECG changes, was found in 34 males (6.18%) and 58 females (10.12%). Risk factor prevalence showed that smoking/tobacco use was present in 201 males (36.5%) and 67 females (11.7%). Physical inactivity, either work-related or leisure time, was seen in 157 males (28.5%) and 130 females (22.7%). Hypertension (> or =140 and/or 90 mmHg) was present in 200 males (36.4%) and 215 females (37.5%). Diabetes diagnosed by history or fasting glucose > or =126 mg/dl was found in 72 males (13.1%) and 65 females (11.3%). Obesity, body mass index > or =27 kg/m2 was present in 135 males (24.5%) and 173 females (30.2%), while truncal obesity (waist:hip >0.9 males, >0.8 females) was found in 316 males (57.4%) and 392 females (68.4%). The most common dyslipidemia in both males and females was low HDL-cholesterol (<40 mg/dl: males 54.9%, females 54.2%). High total cholesterol levels of > or =200 mg/dl (males 37.4%, females 4.1%), high LDL-cholesterol levels of > or =130 mg/dl (males 37.0%, females 45.8%) and high levels of triglycerides > or = 150 mg/dl (males 32.3%, females 28.6%) were also seen in a significant number. Hypertension, obesity, truncal obesity, diabetes and dyslipidemias increased significantly with age in both males and females (Mantel-Haenzel chi2 for trend, p<0.05). CONCLUSIONS: There is a high prevalence of standard coronary risk factors--smoking, physical inactivity, hypertension, hypercholesterolemia, diabetes and obesity--as well as factors peculiar to south Asians--truncal obesity, low HDL-cholesterol and high triglycerides--in this urban Indian population. As compared to a previous study in the early 1900s in a similar population, there is a significant increase in the number of people with obesity, diabetes and dyslipidemias.

Adult↗
PubMedDate not supplied

Laser and surgical management of hyperplastic persistent pupillary membrane.

Two patients (50 and 14 years old) presented with extensive hyperplastic pupillary membranes and significant reduction of visual acuity. The patients were treated by surgical excision and sectioning of the membrane using a Q-switched Nd:YAG laser. Although both of the modalities achieved good surgical and functional results, laser treatment should be preferred over surgery because of potential complications associated with the latter.

Adolescent↗
PubMedDate not supplied

Nd:YAG laser photocystotomy of a free-floating pigmented anterior vitreous cyst.

An 8-year-old girl presented with a free-floating pigmented cyst in the anterior vitreous causing a large, visually disturbing floater. A simple laser photocystotomy with a single-frequency Nd:YAG laser resulted in a reduction in the size of the cyst but persistence of the floater. An attempt at further laser fragmentation of the cyst resulted in iatrogenic cataract formation.

Child↗
PubMedDate not supplied

High prevalence of multiple coronary risk factors in Punjabi Bhatia community: Jaipur Heart Watch-3.

BACKGROUND: Studies among emigrant Indian populations have shown a high prevalence of obesity and many coronary risk factors in Bhatia community. To determine the prevalence of risk factors in this community within India we performed an epidemiological study. METHODS AND RESULTS: An ethnic-group sample survey to determine prevalence of cardiovascular risk factors was performed using community registers for enrollment. Methodology used was similar to Jaipur Heart Watch studies performed in 1995 and 2002. We invited 600 randomly selected subjects listed in Punjabi Bhatia community registers and could examine 458 (76.7%) persons (men 226, women 232). Evaluation for coronary risk factors, anthropometric measurements, blood pressure, electrocardiogram, fasting blood glucose and serum lipids was performed using standard definitions. Mean age was 43.2 +/- 14.6 years in men and 44.7 +/- 15.3 years in women. In both men and women there was a high prevalence of family history of coronary heart disease in 45 (19.9%) and 50 (21.6%), family history of diabetes in 96 (42.5%) and 77 (33.2%), sedentary habits in 82 (36.3%) and 73 (31.5%), smoking or tobacco use in 59 (26.1%) and 4 (1.7%), overweight or obesity (body mass index > or = 25 kg/m2) in 123 (54.0%) and 161 (69.4%), severe obesity (body mass index >30 kg/m2) in 47 (20.8%) and 75 (32.3%), truncal obesity (waist-hip ratio: men >0.9, women >0.8) in 175 (77.4%) and 186 (80.2%), increased waist (waist size: men >102 cm, women >88 cm) in 78 (34.5%) and 129 (55.6%), hypertension (blood pressure > or = 140/90 mmHg) in 116 (51.3%) and 120 (51.3%), diabetes in 40 (17.7%) and 33 (14.2%), hypercholesterolemia (total cholesterol > or = 200 mg/dl) in 75 (33.2%) and 67 (28.9%), high triglycerides in 55 (24.3%) and 34 (14.7%), low high-density lipoprotein cholesterol in 169 (74.8%) and 155 (66.8%), and the metabolic syndrome (defined by American National Cholesterol Education Program) in 84 (36.2%) and 111 (47.8%) respectively. Body mass index correlated significantly with (age-adjusted r2 value--men, women) waist diameter (0.52, 0.12), waist-hip ratio (0.21, 0.10), truncal obesity (0.54, 0.60), systolic blood pressure (0.19, 0.16), diastolic blood pressure (0.12, 0.16), hypertension (0.19, 0.31), and metabolic syndrome (0.28, 0.44) (p<0.05). There was a significant linear relationship of body mass index with the prevalence of hypertension, hypercholesterolemia, diabetes (women), and the metabolic syndrome (chi2 for trend p<0.05). Prevalence of these risk factors was the lowest in subjects with body mass index <20 kg/m2. A multivariate ordinal logistic regression analysis revealed that obesity was independently associated with multiple risk factors characterized by metabolic syndrome after adjustment for age, hypertension, and diabetes in both men (odds ratio 2.45, 95% confidence intervals 1.69, 3.57) as well as in women (odds ratio 2.93, 95% confidence intervals 1.86, 4.61) (p<0.01). CONCLUSIONS: There is a high prevalence of obesity, abdominal obesity, hypertension, diabetes, lipid abnormalities and the metabolic syndrome in this community that is significantly greater than reported studies in Jaipur and urban populations elsewhere in India. Obesity correlates strongly with multiple coronary risk factors of which it is an important determinant.

Adult↗