912 resultados para Group association


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BACKGROUND: Deposition of beta-amyloid in the brains of patients with Alzheimer's disease is thought to precede a chain of events that leads to an inflammatory response by the brain. We postulated that genetic variation in the regulatory region of the gene for the proinflammatory cytokine tumour necrosis factor alpha (TNF-alpha) leads to increased risk of Alzheimer's disease and vascular dementia. METHODS: A polymorphism in the regulatory region of the TNF-alpha gene was analysed in a case-control study. The polymorphism (C-850T) was typed in 242 patients with sporadic Alzheimer's disease, 81 patients with vascular dementia, 61 stroke patients without dementia, and 235 normal controls. These groups of individuals were also genotyped for the apolipoprotein E polymorphism, and the vascular dementia and stroke groups were typed at the HLA-DR locus. FINDINGS: The distribution of TNF-alpha genotypes in the vascular dementia group differed significantly from that in the stroke and normal control groups, giving an odds ratio of 2.51 (95% CI 1.49-4.21) for the development of vascular dementia for individuals with a CT or TT genotype. Logistic regression analysis indicated that the possession of the T allele significantly increased the risk of Alzheimer's disease associated with carriage of the apolipoprotein E epsilon4 allele (odds ratio 2.73 [1.68-4.44] for those with apolipoprotein E epsilon4 but no TNF-alpha T, vs 4.62 [2.38-8.96] for those with apolipoprotein E epsilon4 and TNF-alpha T; p=0.03). INTERPRETATION: Possession of the TNF-alpha T allele significantly increases the risk of vascular dementia, and increases the risk of Alzheimer's disease associated with apolipoprotein E. Although further research is needed, these findings suggest a potential role for anti-inflammatory therapy in vascular dementia and Alzheimer's disease, and perhaps especially in patients who have had a stroke.

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The aim of this study was to analyze if the perceptions of students before and after carrying out the work, that is, their perception of different aspects of the functioning of the group, the working skills acquired as well as those they think that need to be improved, varied depending on whether the contribution of the different members of the group was being co-evaluated or not. 144 students of Physical Activity and Sport Sciences participated in this study. In order to analyze the students' perception of group work the adapted questionnaire by Bourne et al. (2001) was used. Results showed that groups which implemented co-evaluation assessed more negatively the experience in general than those which did not. However, co-evaluation groups perceived their competence to work as a team had improved to a greater extent than the groups without co-evaluation, evaluating more positively both the performance and the result of work and increasing their knowledge of the other team members. Using a co-evaluation system seems to generate both a better assessment of the running of the team and the result of its work.

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Reflux of gastric contents can lead to development of reflux esophagitis and Barrett's esophagus. Barrett's esophagus is a risk factor for esophageal adenocarcinoma. Damage to DNA may lead to carcinogenesis but is repaired through activation of pathways involving polymorphic enzymes, including human 8-oxoguanine glycosylase 1 (hOGG1), X-ray repair cross-complementing 1 (XRCC1), and xeroderma pigmentosum group D (XPD). Of the single nucleotide polymorphisms identified in these genes, hOGG1 Ser 326Cys, XRCC1 Arg 399Gln, and XPD Lys 751Gln are particularly common in Caucasians and have been associated with lower DNA repair capacity. Small studies have reported associations with XPD Lys 751Gln and esophageal adenocarcinoma. XRCC1 Arg 399Gln has been linked to Barrett's esophagus and reflux esophagitis. In a population-based case-control study, we examined associations of the hOGG1 Ser 326Cys, XRCC1 Arg 399Gln, and XPD Lys 751Gln polymorphisms with risk of esophageal adenocarcinoma, Barrett's esophagus, and reflux esophagitis. Genomic DNA was extracted from blood samples collected from cases of esophageal adenocarcinoma (n = 210), Barrett's esophagus (n = 212), reflux esophagitis (n = 230), and normal population controls frequency matched for age and sex (n = 248). Polymorphisms were genotyped using Taq-Man allelic discrimination assays. Odds ratios and 95% confidence intervals were obtained from logistic regression models adjusted for potential confounding factors. There were no statistically significant associations between these polymorphisms and risk of esophageal adenocarcinoma, Barrett's esophagus, or reflux esophagitis.

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Objective: To examine the association between breastfeeding and blood pressure, anthropometry, and plasma lipid profile in both adolescence and young adulthood. Design: Longitudinal study of biological and behavioural risk factors for cardiovascular disease. Setting: The Young Hearts Project, Northern Ireland Subjects: School children aged 12 years and 15 years who participated in a cross-sectional study of lifestyle and health, and who were followed up as young adults aged 20 – 25 years. Results: There was no significant difference in height, weight, BMI, skin-fold thickness measurements, blood pressure or plasma lipid profile in adolescents who had been breastfed when compared to those who had not been breastfed. However, by the time these adolescents had reached adulthood, those who had been breastfed were significantly taller when compared to those who had not been breastfed (standing height, P=0.013; leg length (P=0.035)). Specifically, the breastfed group were on average taller by 1.7cm (95% CI 0.4, 3.0) and had longer legs by 1cm (95% CI 0.1, 1.9). There was no significant difference in other anthropometric measures, blood pressure or plasma lipid profile in adults who had been breastfed when compared to those who had not been breastfed. Conclusions: Compared with those who had not been breastfed, individuals who had been breastfed were taller in adulthood. Given the known association of increased adult height with improved life expectancy the results from this study support a beneficial effect of breastfeeding.

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Objective: Both neurocognitive impairments and a history of childhood abuse are highly prevalent in patients with schizophrenia. Childhood trauma has been associated with memory impairment as well as hippocampal volume reduction in adult survivors. The aim of the following study was to examine the contribution of childhood adversity to verbal memory functioning in people with schizophrenia. Methods: Eighty-five outpatients with a Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) diagnosis of chronic schizophrenia were separated into 2 groups on the basis of self-reports of childhood trauma. Performance on measures of episodic narrative memory, list learning, and working memory was then compared using multivariate analysis of covariance. Results: Thirty-eight (45%) participants reported moderate to severe levels of childhood adversity, while 47 (55%) reported no or low levels of childhood adversity. After controlling for premorbid IQ and current depressive symptoms, the childhood trauma group had significantly poorer working memory and episodic narrative memory. However, list learning was similar between groups. Conclusion: Childhood trauma is an important variable that can contribute to specific ongoing memory impairments in schizophrenia.

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Two studies were carried out in England to investigate the role of essentialist national group definitions in determining the effect of national identification on prejudice towards immigrants, and asylum seekers in particular. It was expected that the relationship between national identification and prejudice would depend on the degree to which participants endorse an essentialist (`ethnic') definition of their nationality. Consistent with this, Study 1 (N=154) found that national identification is associated with negativity towards asylum seekers only among individuals who endorse an essentialist conception of the group, and shows no significant association with prejudice among those who reject such a conception. Study 2 (N=219) used a longitudinal design conducted over 6 weeks, allowing cross-lagged analysis of causality between essentialism, identification, and behavioural intentions towards asylum seekers. A causal effect of essentialism on willingness to support a group acting against asylum seekers was observed, with no significant causal effect in the reverse direction. The reverse causal direction was observed in the case of support for a group seeking to support asylum seekers, with intended behaviours determining essentialism. The results are discussed in terms of the importance of group definitions in the study of in-group affiliations and prejudice.

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Background Polymorphisms in ACE and AGTR1 genes have been assessed in multiple studies for association with diabetic nephropathy; however, results are conflicting. The ACE2 gene has not been studied extensively for association with diabetic nephropathy.

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Context: Caveolin-1 (CAV1) is an inhibitor of tissue fibrosis.
Objective: To study the association of CAV1 gene variation with kidney transplant outcome, using kidney transplantation as a model of accelerated fibrosis.
Design, Setting, and Patients: Candidate gene association and validation study. Genomic DNA from 785 white kidney transplant donors and their respective recipients (transplantations in Birmingham, England, between 1996 and 2006; median followup, 81 months) were analyzed for common variation in CAV1 using a singlenucleotide polymorphism (SNP) tagging approach. Validation of positive findings was sought in an independent kidney transplant donor-recipient cohort (transplantations in Belfast, Northern Ireland, between 1986 and 2005; n=697; median follow-up, 69 months). Association between genotype and allograft failure was initially assessed by Kaplan-Meier analysis, then in an adjusted Cox model.
Main Outcome Measure: Death-censored allograft failure, defined as a return to dialysis or retransplantation.
Results: The presence of donor AA genotype for the CAV1 rs4730751 SNP was associated with increased risk of allograft failure in the Birmingham group (donor AA vs non-AA genotype in adjusted Cox model, hazard ratio [HR], 1.97; 95% confidence interval [CI], 1.29-3.16; P=.002). No other tag SNPs showed a significant association. This finding was validated in the Belfast cohort (in adjusted Cox model, HR, 1.56; 95% CI, 1.07-2.27; P=.02). Overall graft failure rates were as follows: for the Birmingham cohort, donor genotype AA, 22 of 57 (38.6%); genotype CC, 96 of 431 (22.3%); and genotype AC, 66 of 297 (22.2%); and for the Belfast cohort, donor genotype AA, 32 of 48 (67%); genotype CC, 150 of 358 (42%); and genotype AC, 119 of 273 (44%).
Conclusion: Among kidney transplant donors, the CAV1 rs4730751 SNP was significantly associated with allograft failure in 2 independent cohorts.

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Robust associations between the dysbindin gene (DTNBP1) and schizophrenia have been demonstrated in many but not all samples, and evidence that this gene particularly predisposes to negative symptoms in this illness has been presented. The current study sought to replicate the previously reported negative symptom associations in an Irish case-control sample. Association between dysbindin and schizophrenia has been established in this cohort, and a factor analysis of the assessed symptoms yielded three factors, Positive, Negative, and Schneiderian. The sequential addition method was applied using UNPHASED to assess the relationship between these symptom factors and the high-risk haplotype. No associations were detected for any of the symptom factors indicating that the dysbindin risk haplotype does not predispose to a particular group of symptoms in this sample. Several possibilities, such as differing risk haplotypes, may explain this finding. (C) 2009 Wiley-Liss, Inc.

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Variation in the apolipoprotein E gene (APOE) has been reported to be associated with longevity in humans. The authors assessed the allelic distribution of APOE isoforms e2, e3, and e4 among 10,623 participants from 15 case-control and cohort studies of age-related macular degeneration (AMD) in populations of European ancestry (study dates ranged from 1990 to 2009). The authors included only the 10,623 control subjects from these studies who were classified as having no evidence of AMD, since variation within the APOE gene has previously been associated with AMD. In an analysis stratified by study center, gender, and smoking status, there was a decreasing frequency of the APOE e4 isoform with increasing age (?2 for trend = 14.9 (1 df); P = 0.0001), with a concomitant increase in the e3 isoform (?2 for trend = 11.3 (1 df); P = 0.001). The association with age was strongest in e4 homozygotes; the frequency of e4 homozygosity decreased from 2.7% for participants aged 60 years or less to 0.8% for those over age 85 years, while the proportion of participants with the e3/e4 genotype decreased from 26.8% to 17.5% across the same age range. Gender had no significant effect on the isoform frequencies. This study provides strong support for an association of the APOE gene with human longevity.

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Age-related macular degeneration (AMD) is the most common cause of incurable visual impairment in high-income countries. Previous studies report inconsistent associations between AMD and apolipoprotein E (APOE), a lipid transport protein involved in low-density cholesterol modulation. Potential interaction between APOE and sex, and smoking status has been reported. We present a pooled analysis (n = 21,160) demonstrating associations between late AMD and APOe4 (odds ratio [OR] = 0.72 per haplotype; confidence interval [CI]: 0.65-0.74; P = 4.41×10(-11) ) and APOe2 (OR = 1.83 for homozygote carriers; CI: 1.04-3.23; P = 0.04), following adjustment for age group and sex within each study and smoking status. No evidence of interaction between APOE and sex or smoking was found. Ever smokers had significant increased risk relative to never smokers for both neovascular (OR = 1.54; CI: 1.38-1.72; P = 2.8×10(-15) ) and atrophic (OR = 1.38; CI: 1.18-1.61; P = 3.37×10(-5) ) AMD but not early AMD (OR = 0.94; CI: 0.86-1.03; P = 0.16), implicating smoking as a major contributing factor to disease progression from early signs to the visually disabling late forms. Extended haplotype analysis incorporating rs405509 did not identify additional risks beyond e2 and e4 haplotypes. Our expanded analysis substantially improves our understanding of the association between the APOE locus and AMD. It further provides evidence supporting the role of cholesterol modulation, and low-density cholesterol specifically, in AMD disease etiology.

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In adults, both active and passive smoking reduce levels of exhaled nitric oxide (eNO); however, to date, passive exposure to environmental tobacco smoke (ETS) has not been shown to affect eNO in children. The authors recruited 174 asthmatic children (96 male, 78 female) and 79 nonasthmatic controls (46 male, 33 female) from a group of children aged 5 to 14 yr who attended a children's hospital for an outpatient visit or elective surgery. Each subject's exposure to ETS was ascertained by questionnaire, and their eNO levels were measured. Asthmatic children had higher eNO levels (ppb) than nonasthmatic children (p = 0.04), and asthmatic children exposed to ETS had significantly lower eNO levels than unexposed children (p = 0.005). Exposure to ETS did not alter eNO levels in nonasthmatic children (p = 0.4). Results of the study suggest that ETS exposure is associated with lower eNO levels among childhood asthmatics. Consequently, ETS exposure may need to be considered when physicians interpret eNO levels in asthmatic children. Further study of the effects of ETS on eNO levels is recommended.

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AIMS/HYPOTHESIS: Parental type 2 diabetes mellitus increases the risk of diabetic nephropathy in offspring with type 1 diabetes mellitus. Several single nucleotide polymorphisms (SNPs) that predispose to type 2 diabetes mellitus have recently been identified. It is, however, not known whether such SNPs also confer susceptibility to diabetic nephropathy in patients with type 1 diabetes mellitus. METHODS: We genotyped nine SNPs associated with type 2 diabetes mellitus in genome-wide association studies in the Finnish population, and tested for their association with diabetic nephropathy as well as with severe retinopathy and cardiovascular disease in 2,963 patients with type 1 diabetes mellitus. Replication of significant SNPs was sought in 2,980 patients from three other cohorts. RESULTS: In the discovery cohort, rs10811661 near gene CDKN2A/B was associated with diabetic nephropathy. The association remained after robust Bonferroni correction for the total number of tests performed in this study (OR 1.33 [95% CI 1.14, 1.56], p?=?0.00045, p (36tests)?=?0.016). In the meta-analysis, the combined result for diabetic nephropathy was significant, with a fixed effects p value of 0.011 (OR 1.15 [95% CI 1.02, 1.29]). The association was particularly strong when patients with end-stage renal disease were compared with controls (OR 1.35 [95% CI 1.13, 1.60], p?=?0.00038). The same SNP was also associated with severe retinopathy (OR 1.37 [95% CI 1.10, 1.69] p?=?0.0040), but the association did not remain after Bonferroni correction (p (36tests)?=?0.14). None of the other selected SNPs was associated with nephropathy, severe retinopathy or cardiovascular disease. CONCLUSIONS/INTERPRETATION: A SNP predisposing to type 2 diabetes mellitus, rs10811661 near CDKN2A/B, is associated with diabetic nephropathy in patients with type 1 diabetes mellitus.