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Biomedical subjects

G P Singh

Publications and source records attributed to G P Singh.

At least 19 recordsLinked to original sources
PubMed2025

Development and validation of a high-density 'Amahysnp' genotyping array in grain amaranth (Amaranthus hypochondriacus).

BACKGROUND: Grain amaranth has recently gained global attention as a promising crop alternative to traditional cereals due to its nutritional value and adaptability to various growing conditions. Although gene banks conserve extensive collections of amaranth germplasm, the genomic and phenotypic characterization of these resources is limited, which hinders their full utilization in breeding programs. A major challenge is the lack of high-throughput genotyping assays essential for comprehensive genomic characterization and trait mapping. High-density SNP arrays have become standard tools for genome-wide analysis across multiple loci, enabling molecular breeding across a range of crop species. RESULTS: In this study, we developed a 64 K high-throughput SNP genotyping array named "AmahySNP", using Affymetrix® Axiom® technology. The array contains 64,069 high-density SNPs distributed across both genic (55.17%) and non-genic (44.83%) regions of the Amaranthus hypochondriacus genome. The genic region includes 8,879 genes, which consist of 4,830 single-copy genes and 4,049 multi-copy genes distributed across 16 scaffolds. These genes cover various functional regions, including exons (10.5%), introns (40.1%), 5'UTRs (1.6%), and 3'UTRs (2.9%), respectively. The AmahySNP array was effectively utilized for population structure analysis, genetic diversity studies, core development, and genome wide association studies (GWAS) in amaranth germplasm. A representative core set of 112 accessions was identified, which includes two released varieties (Annapurna and Suvarna) and 100 diverse accessions from 12 different regions, representing 12% of the total 917 accessions evaluated. Phylogenetic analysis revealed three major genetic clusters, independent of their geographical origins. GWAS conducted using 22,763 polymorphic SNPs from 540 genotypes identified 13 novel loci associated days to flowering (DTF) trait, seven of which were located within annotated genes. CONCLUSIONS: The AmahySNP 64 K SNP chip a valuable genomic tool for amaranth research and breeding with a strong potential to accelerate its genetic improvement. It enables high-throughput genotyping for a wide range of applications, including GWAS and other genomic studies, and will significantly advance the exploration of natural genetic variations. Ultimately, this resource will empower amaranth breeders to develop improved amaranth cultivars with enhanced crop yield, resilience, and nutritional quality, contributing to global food security and sustainable agriculture.

Amaranthus↗
PubMed2001

Plasma concentrations of lipid peroxidation products in children with acute leukaemia.

Acute leukaemia is the most common childhood malignancy. The cause of leukaemia is not known in most of the cases and of late free radicals have been implicated in the pathogenesis of leukaemia. The degree of lipid peroxidation was studied in the present study as a marker of disease activity in 15 patients of acute lymphoblastic leukaemia and 20 healthy age and sex matched individuals served as control. Serum malonaldehyde (MDA) levels were increased in leukaemia and were higher in the active phase of disease as compared to those in remission, Hence, serum MDA estimation in leukaemia can be of help in diagnosis and to predict the chances of relapse.

Biomarkers, Tumor↗
PubMed2000

Effect of smoking on lipid profile, lipid peroxidation and antioxidant status in normal subjects and in patients during and after acute myocardial infarction.

We studied changes in lipid peroxidation, vitamin E status and lipid profile due to smoking in healthy subjects, patients with acute myocardial infarction (MI), and in stabilized patients surviving MI. A significant increase in malondialdehyde (MDA) concentrations was observed in MI patients, more than in smokers (P<0.05), as compared to control. The plasma vitamin E as well as the ratio of vitamin E/lipids were significantly lower in MI patients as compared to stable ischemic heart disease (IHD) patients and controls. Our data show that smoking is associated with lowered antioxidant status in MI.

Adult↗
PubMed2000

Evaluation of oxidative stress before and after control of glycemia and after vitamin E supplementation in diabetic patients.

The present study evaluates the presence of oxidative stress in the uncontrolled diabetic state. Glycemic control reduced the oxidative stress, but total normalization of the parameters of oxidative stress was not achieved, indicating continued oxidant injury despite optimal control of the diabetes. Vitamin E supplementation for 4 weeks in these patients further reduced the oxidative stress, suggesting that vitamin E supplementation might be helpful in reducing free-radical-induced oxidant injury.

Adult↗
PubMed2000

Superoxide anion formation and glutathione levels in patients with preeclampsia.

Increased free radical activity has been implicated in the pathogenesis of preeclampsia. This article investigates the glutathione status in preeclampsia and whether superoxide generation is enhanced in preeclampsia. Venous blood samples were obtained from 30 preeclamptic women and 30 normotensive pregnant women (controls). Superoxide generation and glutathione content were measured. There was a significant increase in superoxide generation and a marked reduction in glutathione content in preeclamptic women as compared to controls (p < 0.001). These results indicate that enhanced superoxide generation and impaired glutathione metabolism may be involved in the pathogenesis of preeclampsia.

Adolescent↗
PubMed2000

Effect of glycemic control and vitamin E supplementation on total glutathione content in non-insulin-dependent diabetes mellitus.

Thirty patients with non-insulin-dependent diabetes mellitus were selected for the study. 15 age-matched healthy volunteers served as controls. Serum malonaldehyde, total glutathione, and vitamin E levels were estimated before and after glycemic control and after 4 weeks of vitamin E supplementation. Both total glutathione and vitamin E levels increased after glycemic control and showed an increase after vitamin E supplementation. Malonaldehyde levels lowered after glycemic control, but remained higher than controls. Since vitamin E supplementation significantly decreased oxidative stress in the present study, it may play a role in reducing free-radical-induced oxidant injury in diabetes mellitus.

Blood Glucose↗
PubMed2000

Role of oxygen free radicals in shock.

AIMS OF THE STUDY: To study lipid peroxidation, magnesium levels (Mg) in plasma and red cells (RBC), superoxide dismutase (SOD) and catalase (CAT) activities in the plasma and RBC of shock patients. METHODOLOGY: Twenty five patients with clinically defined septic shock and 30 healthy volunteers were selected for the study to study the parameters of oxidative stress. RESULTS: Septic shock patients had higher activities of plasma and RBC SOD and CAT activities as compared to control. Also, plasma Mg and malonaldehyde (MDA) levels were higher in shock patients as compared to controls. While, RBC Mg levels were similar in two groups. CONCLUSIONS: The finding of increased concentration of MDA, Mg, SOD and CAT in sepsis implicates oxygen free radicals in the pathophysiology and free radical scavengers may have a role in organ preservation.

Adult↗
PubMed2000

Glutathione levels in health and sickness.

We speculate that the glutathione (GSH) status of human subjects could be an indicator of health and functional age. In this regard, in a study in which, 80 young and 40 elderly healthy individuals were selected as control. We also studied 145 patients with chronic illnesses namely, ischaemic heart disease, diabetes, preeclampsia, cataract, chronic renal failure and leukaemia (age 52 +/- 8.6 years). We observed that all the subjects had high malonadildehyde and low glutathione levels as compared to control. These early observations support the hypothesis that oxidative stress may have an important aetiological rule and antioxidants a potential therapeutic role.

Adult↗
PubMed2000

Oxidative stress after acute myocardial infarction: effect of thrombolytic treatment.

OBJECTIVE: Treatment with thrombolysis plays a crucial role in salvaging the myocardium in myocardial infarction (MI) patients, but reperfusion of ischaemic areas may itself be associated with reperfusion injury mediated by free radical induced oxidation. Hence the present study was planned to evaluate oxidative stress in patients receiving thrombolytic therapy during MI and to compare them with those not receiving thrombolysis. METHODS: Thiobarbituric acid reactive substance (TBARS) was used as a marker of lipid peroxidation in 30 patients after acute MI. Thirteen were treated by intravenous thrombolysis and 17 served as control. Also, vitamin E levels were estimated in these patients. RESULTS: Patients treated with thrombolysis showed a fall in vitamin E and increase in TBARS within first hours. The decrease in vitamin E was independent of a change in cholesterol. However, the levels were similar at 72 hours. CONCLUSION: The results indicate increased free radical production after MI and reperfusion also increases in free radical production and antioxidants may have a part in improving thrombolytic reperfusion of ischaemic myocardium.

Aged↗
PubMed1999

Distribution of blood viscosity values and biochemical correlates in healthy adults.

OBJECTIVE: Increase in the viscosity of blood predict clinical manifestation of atherothrombotic vascular disease. The clinical utility of viscosity measurements in cardiovascular risk factor requires a reference value established from a healthy disease free population. METHODS: Blood viscosity (based on empirical Merill's formula), fibrinogen, haematocrit and lipid profile were measured in 100 fasting healthy nonsmoking adults (50 men, 50 women). RESULTS: The mean (+/- SD) blood viscosity values were 0.030 +/- 0.015 dyne/cm2. Men had higher viscosity values than women. Also, men had higher triglycerides, haematocrit as well as fibrinogen as compared to women. CONCLUSION: This study provides reference values for the blood viscosity, fibrinogen haematocrit and lipid profile. Viscosity measurements may improve identification and risk stratification of patients at high risk for atherothrombotic vascular disease and its complications.

Adult↗
PubMed1998

Effect of adenotonsillectomy on arterial blood gases and acid-base balance.

Adenotonsillitis is quite common in children in India and untreated cases may land up with serious cardiopulmonary complications which promoted us to study arterial blood gases and acid-base balance in these patients. The study was conducted in 30 children with chronic adenotonsillitis and 30 age and sex matched controls. Arterialized capillary blood samples were taken before and 1 month after surgery while the subject was sleeping. Relative hypoxemia, rise in pCO2 and increased bicarbonates was observed in the study group, whereas change in pH was insignificant. The study showed that ventilatory impairment associated with adenotonsillar hypertrophy which manifests as hypoxia, hypercarbia and raised bicarbonate levels was reversed after adenotonsillectomy.

Acid-Base Equilibrium↗
PubMed1998

Lipid peroxidation and vitamin E levels in preeclampsia.

Twenty preeclamptic, 25 normotensive pregnant and 25 healthy nonpregnant women were analyzed with regard to serum malonaldehyde (MDA), vitamin E and lipid profile. In preeclampsia, MDA was significantly higher than control. MDA also showed high correlation to the level of blood pressure. Serum cholesterol and triglycerides were increased in normotensive women and still higher in preeclamptic women. A highly significant fall in vitamin E levels in preeclamptic women was noted as compared to control groups. Our study supports the view that an increased lipid peroxidation may be involved in vasoconstriction in preeclampsia.

Adult↗
PubMed1998

Improved tolerability of felodipine compared with amlodipine in elderly hypertensives: a randomised, double-blind study in 535 patients, focusing on vasodilatory adverse events. The International Study Group.

The primary aim of this double-blind, parallel group trial was to compare incidence of newly occurring vasodilatory adverse events in elderly patients treated with recommended once-daily doses of felodipine extended release (ER) or amlodipine. A total of 535 patients over 65 years old with a sitting diastolic blood pressure of 90-115 mmHg and/or systolic blood pressure 160-220 mmHg, were recruited at 46 centres worldwide. Patients were randomised to felodipine ER 2.5 mg or amlodipine 5 mg. If blood pressure was > 160/90 mmHg after three or six weeks, felodipine ER was increased to 5 and 10 mg and amlodipine to 10 mg. After nine weeks, average doses of felodipine ER and amlodipine were 5.5 mg and 7.3 mg, respectively. Newly occurring vasodilatory adverse events were reported by 32% of felodipine ER patients and 43% of amlodipine patients (p = 0.007). Both treatments effectively reduced blood pressure 24 hours post-dose. Using a low starting dose and individual titration, felodipine ER achieves good control of blood pressure with few vasodilatory side-effects.

Aged↗
PubMed1997

Lipid peroxidation and vitamin E in ischemic heart disease.

The study was carried on 90 adult cases which were divided into 3 groups of 30 cases each. Group A consisted of 30 normal healthy controls whereas Group B and C comprised of 30 patients each of chronic stable ischaemic heart disease and of acute myocardial infarction (AMI), respectively. Patients in all the 3 groups were age and sex matched. Group C consisted of 17 cases of anterior wall myocardial infarction, 10 of inferior wall, 2 of anterolateral and 1 of antero-inferior MI and they had an average 6.96 +/- 3.39 hours of chest pain before hospitalization. Serum vitamin E in group A, B and C on day 1 was 7.90 +/- 3.23, 5.345 +/- 2.37 and 1.302 +/- 1.090 micrograms/ml, respectively and malondialdehyde (MDA) levels in these groups were 0.759 +/- 0.27, 0.780 +/- 0.334 and 3.092 +/- 1.124 nmol/ml, respectively. Vitamin E and MDA levels in group C on day 3 were 3.382 +/- 1.088 micrograms/ml and 1.492 +/- 0.849 nmol/ml, respectively. In Group C, vitamin E levels were significantly decreased (p < 0.001) as compared to controls and remained low after 2 days. MDA levels were raised more than 3 times in AMI group (p < 0.01) and decreased slightly after 2 days but were elevated compared to controls. Findings suggest that vitamin E deficiency is inversely related to lipid peroxidation and is elevated during AMI. Therefore supplementation of vitamin E in AMI would be beneficial.

Coronary Disease↗