Search results for "India"

Epistasis and the Adaptability of an RNA Virus

2005

Abstract We have explored the patterns of fitness recovery in the vesicular stomatitis RNA virus. We show that, in our experimental setting, reversions to the wild-type genotype were rare and fitness recovery was at least partially driven by compensatory mutations. We compared compensatory adaptation for genotypes carrying (1) mutations with varying deleterious fitness effects, (2) one or two deleterious mutations, and (3) pairs of mutations showing differences in the strength and sign of epistasis. In all cases, we found that the rate of fitness recovery and the proportion of reversions were positively affected by population size. Additionally, we observed that mutations with large fitness…

Microsatellite allele 5.1 of major histocompatibility complex class I chain related gene A (MIC-A) is increased among non-insulin dependent diabetes …

2000

Following the very initial growth of biological RNA viral clones

2005

Due to their extremely high genetic diversity, which is a direct consequence of high mutation rates, RNA viruses are often described as molecular quasispecies. According to this theory, RNA virus populations cannot be understood in terms of individual viral clones, as they are clouds of interconnected mutants, but this prediction has not yet been demonstrated experimentally. The goal of this study was to determine the fitness of individual clones sampled from a given RNA virus population, a necessary previous step to test the above prediction. To do so, limiting dilutions of a vesicular stomatitis virus population were employed to isolate single viral clones and their initial growth dynamic…

Repeated transfer of small RNA virus populations leading to balanced fitness with infrequent stochastic drift

1996

The population dynamics of RNA viruses have an important influence on fitness variation and, in consequence, on the adaptative potential and virulence of this ubiquitous group of pathogens. Earlier work with vesicular stomatitis virus showed that large population transfers were reproducibly associated with fitness increases, whereas repeated transfers from plaque to plaque (genetic bottlenecks) lead to losses in fitness. We demonstrate here that repeated five-plaque to five-plaque passage series yield long-term fitness stability, except for occasional stochastic fitness jumps. Repeated five-plaque passages regularly alternating with two consecutive large population transmissions did not cau…

Significant association of MTHFD1 1958GA single nucleotide polymorphism with nonsyndromic cleft lip and palate in Indian population.

2014

Objectives: Nonsyndromic cleft lip and palate (NSCLP) is genetically distinct from those with syndromic clefts, and accounts for ~70% of cases with Oral clefts. Folate, or vitamin B9, is an essential nutrient in our diet. Allelic variants in genes involved in the folate pathway might be expected to have an impact on risk of oral clefts. Given the key role of methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) in folate metabolism, it would be of significant interest to assess its role in NSCLP etiology. Study Design: The present study aims at examining the association between MTHFD1 1958G>A polymorphism and NSCLP risk by conducting a case-control study in south Indian population. Our sample …

Intraseasonal rainfall variability over Madagascar

2016

International audience; Using daily rain-gauge records for Madagascar and nearby islands, this paper investigates rainfall intraseasonal variability at local and regional scales during the austral summer season (November–February), as well as the respective influences of recurrent convective regimes over the South-West Indian Ocean (SWIO) and the Madden-Julian Oscillation (MJO). Our results show a general consistency between local-scale rainfall variability in Madagascar and regional-scale features of climate variability. The influence of Tropical-Temperate Troughs in their mature phase and/or their easternmost locations is first underlined. The development of such systems over Southern Afr…

Multimorbidity and perceived stress: a population-based cross-sectional study among older adults across six low- and middle-income countries

2018

BACKGROUND:\ud Stress in chronic conditions or multimorbidity (≥2 chronic conditions) has been reported to affect clinical outcomes but there are no studies on the association between stress and chronic conditions/multimorbidity among older adults in low- and middle-income countries (LMICs). Thus, we investigated this association among adults aged ≥50 years across six LMICs.\ud \ud METHODS:\ud A cross-sectional analysis using data from the World Health Organization's Study on Global Ageing and Adult Health (China, Ghana, India, Mexico, Russia, South Africa) was conducted. A perceived stress score [range 0 (lowest stress) -100 (highest stress)] was computed based on two questions from the Pe…

Prevalence and Risk Factors for Vitamin C Deficiency in North and South India: A Two Centre Population Based Study in People Aged 60 Years and Over

2011

BackgroundStudies from the UK and North America have reported vitamin C deficiency in around 1 in 5 men and 1 in 9 women in low income groups. There are few data on vitamin C deficiency in resource poor countries.ObjectivesTo investigate the prevalence of vitamin C deficiency in India.DesignWe carried out a population-based cross-sectional survey in two areas of north and south India. Randomly sampled clusters were enumerated to identify people aged 60 and over. Participants (75% response rate) were interviewed for tobacco, alcohol, cooking fuel use, 24 hour diet recall and underwent anthropometry and blood collection. Vitamin C was measured using an enzyme-based assay in plasma stabilized …

Handgrip strength and depression among 34,129 adults aged 50 years and older in six low- and middle-income countries

2019

Introduction: Handgrip strength is a simple and inexpensive marker of health and mortality risk. It presents an ideal risk-stratifying method for use in low and middle-income countries (LMICs). There are, however, no population-based studies investigating the associations between handgrip strength and depression in LMICs. We aimed to assess these associations among community-dwelling middle-aged and older adults using nationally representative data from six LMICs. Method: Cross-sectional data on individuals aged ≥ 50 years from the World Health Organization's Study on Global Ageing and Adult Health were analyzed. Depression was based on the Composite International Diagnostic Interview. Weak…

Anxiety symptoms and mild cognitive impairment among community-dwelling older adults from low- and middle-income countries.

2021

Abstract Aim Anxiety may be a risk factor for mild cognitive impairment (MCI) but there is a scarcity of data on this association especially from low- and middle-income countries (LMICs). Thus, we investigated the association between anxiety and MCI among older adults residing in six LMICs (China, Ghana, India, Mexico, Russia, South Africa), and the mediational effect of sleep problems in this association. Methods Cross-sectional, community-based, nationally representative data from the WHO Study on global AGEing and adult health (SAGE) were analyzed. The definition of MCI was based on the National Institute on Ageing-Alzheimer's Association criteria. Multivariable logistic regression analy…