59 research outputs found

    The use of dehydroepiandrosterone-treated rats is not a good animal model for the study of metabolic abnormalities in polycystic ovary syndrome

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    Objective: Hyperandrogenism is the hallmark of polycystic ovary syndrome (PCOS). The use of dehydroepiandrosterone (DHEA)-treated rats is thought to be a suitable animal model to study PCOS. In the present study, we assessed the severity of reproductive and metabolic abnormalities in DHEA-treated rats. Material and methods: Immature female Sprague–Dawley rats were divided into control and DHEA-treated groups. Reproductive parameters including estrus cycle and sex hormones were measured after sexual maturity. Adiposity, insulin sensitivity, and plasma lipid profiles were analyzed to assess metabolic profiles. After sacrifice, the insulin signaling pathway and lipogenic genes were analyzed by immunoblotting and polymerase chain reaction, respectively. Results: An abnormal estrus cycle was observed in the DHEA-treated rats. DHEA treatment also increased plasma testosterone levels and caused multiple cystic follicle formation, which is compatible with the definition of PCOS. There were no significant changes in fasting glucose, fasting insulin, plasma lipid profiles, and blood pressure levels. The adiposity of the DHEA-treated rats was also lower than in the control rats. Moreover, glucose tolerance and insulin sensitivity were only mildly impaired in the DHEA-treated rats after oral glucose tolerance and insulin tolerance tests, even though insulin signaling in skeletal muscles was decreased in the DHEA-treated group. Conclusion: DHEA-treated rats had reproductive abnormalities which mimicked symptoms of human PCOS. In metabolic parameters, DHEA treatment did not show insulin resistance in the female rats, suggesting that the use of DHEA-treated rats is not a good animal model for the study of metabolic abnormalities in PCOS. Keywords: Polycystic ovary syndrome, DHEA, Insulin sensitivit

    Five Blood Pressure Loci Identified by an Updated Genome-Wide Linkage Scan: Meta-Analysis of the Family Blood Pressure Program

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    Background A preliminary genome-wide linkage analysis of blood pressure in the Family Blood Pressure Program (FBPP) was reported previously. We harnessed the power and ethnic diversity of the final pooled FBPP dataset to identify novel loci for blood pressure thereby enhancing localization of genes containing less common variants with large effects on blood pressure levels and hypertension. Methods We performed one overall and 4 race-specific meta-analyses of genome-wide blood pressure linkage scans using data on 4,226African-American, 2,154 Asian, 4,229 Caucasian, and 2,435 Mexican- American participants (total N = 13,044). Variance components models were fit to measured (raw) blood pressure levels and two types of antihypertensive medication adjusted blood pressure phenotypes within each of 10 subgroups defined by race and network. A modified Fisher's method was used to combine the P values for each linkage marker across the 10 subgroups. Results Five quantitative trait loci (QTLs) were detected on chromosomes 6p22.3, 8q23.1, 20q13.12, 21q21.1, and 21q21.3 based on significant linkage evidence (defined by logarithm of odds (lod) score ≥3) in at least one meta-analysis and lod scores ≥1 in at least 2 subgroups defined by network and race. The chromosome 8q23.1 locus was supported by Asian-, Caucasian-, and Mexican-American-specific meta-analyses. Conclusions The new QTLs reported justify new candidate gene studies. They may help support results from genome-wide association studies (GWAS) that fall in these QTL regions but fail to achieve the genome-wide significance. American Journal of Hypertension advance online publication 9 December 2010;doi:10.1038/ajh.2010.23

    Evidence in Obese Children: Contribution of Hyperlipidemia, Obesity-Inflammation, and Insulin Sensitivity

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    <div><p>Background</p><p>Evidence shows a high incidence of insulin resistance, inflammation and dyslipidemia in adult obesity. The aim of this study was to assess the relevance of inflammatory markers, circulating lipids, and insulin sensitivity in overweight/obese children.</p><p>Methods</p><p>We enrolled 45 male children (aged 6 to 13 years, lean control = 16, obese = 19, overweight = 10) in this study. The plasma total cholesterol, HDL cholesterol, triglyceride, glucose and insulin levels, the circulating levels of inflammatory factors, such as TNF-α, IL-6, and MCP-1, and the high-sensitive CRP level were determined using quantitative colorimetric sandwich ELISA kits.</p><p>Results</p><p>Compared with the lean control subjects, the obese subjects had obvious insulin resistance, abnormal lipid profiles, and low-grade inflammation. The overweight subjects only exhibited significant insulin resistance and low-grade inflammation. Both TNF-α and leptin levels were higher in the overweight/obese subjects. A concurrent correlation analysis showed that body mass index (BMI) percentile and fasting insulin were positively correlated with insulin resistance, lipid profiles, and inflammatory markers but negatively correlated with adiponectin. A factor analysis identified three domains that explained 74.08% of the total variance among the obese children (factor 1: lipid, 46.05%; factor 2: obesity-inflammation, 15.38%; factor 3: insulin sensitivity domains, 12.65%).</p><p>Conclusions</p><p>Our findings suggest that lipid, obesity-inflammation, and insulin sensitivity domains predominantly exist among obese children. These factors might be applied to predict the outcomes of cardiovascular diseases in the future.</p></div

    Generation and Analysis of the Expressed Sequence Tags from the Mycelium of <i>Ganoderma lucidum</i>

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    <div><p><i>Ganoderma lucidum</i> (<i>G. lucidum</i>) is a medicinal mushroom renowned in East Asia for its potential biological effects. To enable a systematic exploration of the genes associated with the various phenotypes of the fungus, the genome consortium of <i>G. lucidum</i> has carried out an expressed sequence tag (EST) sequencing project. Using a Sanger sequencing based approach, 47,285 ESTs were obtained from <i>in vitro</i> cultures of <i>G. lucidum</i> mycelium of various durations. These ESTs were further clustered and merged into 7,774 non-redundant expressed loci. The features of these expressed contigs were explored in terms of over-representation, alternative splicing, and natural antisense transcripts. Our results provide an invaluable information resource for exploring the <i>G. lucidum</i> transcriptome and its regulation. Many cases of the genes over-represented in fast-growing dikaryotic mycelium are closely related to growth, such as cell wall and bioactive compound synthesis. In addition, the EST-genome alignments containing putative cassette exons and retained introns were manually curated and then used to make inferences about the predominating splice-site recognition mechanism of <i>G. lucidum</i>. Moreover, a number of putative antisense transcripts have been pinpointed, from which we noticed that two cases are likely to reveal hitherto undiscovered biological pathways. To allow users to access the data and the initial analysis of the results of this project, a dedicated web site has been created at <a href="http://csb2.ym.edu.tw/est/" target="_blank">http://csb2.ym.edu.tw/est/</a>.</p></div

    Trans-Ethnic Fine-Mapping of Lipid Loci Identifies Population-Specific Signals and Allelic Heterogeneity That Increases the Trait Variance Explained

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    Genome-wide association studies (GWAS) have identified ~ 100 loci associated with blood lipid levels, but much of the trait heritability remains unexplained, and at most loci the identities of the trait-influencing variants remain unknown. We conducted a trans-ethnic fine-mapping study at 18, 22, and 18 GWAS loci on the Metabochip for their association with triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), respectively, in individuals of African American (n = 6,832), East Asian (n = 9,449), and European (n = 10,829) ancestry. We aimed to identify the variants with strongest association at each locus, identify additional and population-specific signals, refine association signals, and assess the relative significance of previously described functional variants. Among the 58 loci, 33 exhibited evidence of association at P,161024 in at least one ancestry group. Sequential conditional analyses revealed that ten, nine, and four loci in African Americans, Europeans, and East Asians, respectively, exhibited two or more signals. At these loci, accounting for all signals led to a 1.3- to 1.8-fold increase in the explained phenotypic variance compared to the strongest signals. Distinct signals across ancestry groups were identified at PCSK9 and APOA5. Trans-ethnic analyses narrowed the signals to smaller sets of variants at GCKR, PPP1R3B, ABO, LCAT, and ABCA1. Of 27 variants reported previously to have functional effects, 74% exhibited the strongest association at the respective signal. In conclusion, trans-ethnic highdensity genotyping and analysis confirm the presence of allelic heterogeneity, allow the identification of population-specific variants, and limit the number of candidate SNPs for functional studies

    Common <it>ALDH2</it> genetic variants predict development of hypertension in the SAPPHIRe prospective cohort: Gene-environmental interaction with alcohol consumption

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    Abstract Background Genetic variants near/within the ALDH2 gene encoding the mitochondrial aldehyde dehydrogenase 2 have been associated with blood pressure and hypertension in several case–control association studies in East Asian populations. Methods Three common tag single nucleotide polymorphisms (tagSNP) in the ALDH2 gene were genotyped in 1,134 subjects of Chinese origin from the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance (SAPPHIRe) family cohort. We examined whether the ALDH2 SNP genotypes predicted the development of hypertension in the prospective SAPPHIRe cohort. Results Over an average follow-up period of 5.7 years, carriers homozygous for the rs2238152 T allele in the ALDH2 gene were more likely to progress to hypertension than were non-carriers (hazard ratio [HR], 2.88, 95% confidence interval [CI], 1.06-7.84, P = 0.03), corresponding to a population attributable risk of ~7.1%. The risk associated with the rs2238152 T allele were strongest in heavy/moderate alcohol drinkers and was reduced in non-drinkers, indicating an interaction between ALDH2 genetic variants and alcohol intake on the risk of hypertension (P for interaction = 0.04). The risk allele was associated with significantly lower ALDH2 gene expression levels in human adipose tissue. Conclusion ALDH2 genetic variants were associated with progression to hypertension in a prospective Chinese cohort. The association was modified by alcohol consumption.</p

    Lower intake of magnesium and dietary fiber increases the incidence of type 2 diabetes in Taiwanese

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    Several studies have indicated an inverse association between the incidence of diabetes mellitus and magnesium and dietary fiber intake. Few studies have examined both of these associations together, not to mention in Asian populations with prospective study design. We therefore aimed to study how dietary magnesium and fiber intake levels affect diabetes incidence separately or in combination, in a prospective study in Taiwan. Methods: The study subjects were recruited for a longitudinal study, CardioVascular Disease risk FACtor Two-township Study cycle 2 from November 1990. Data from complete baseline information on dietary and biochemical profile and at least one additional follow-up visit were gathered on a total of 1604 healthy subjects aged 30 years and over. Cox proportional hazard model was used to study the association between diabetes incidence and dietary magnesium and fiber intake level estimated from a food frequency questionnaire. Results: A total of 141 diabetes mellitus events were identified and confirmed during the 4.6 years of follow-up (7365.1 person-years). A significantly higher diabetes risk was observed for people in the lowest quintile of total dietary fiber intake (hazard ratio = 2.04; 95% CI = 1.17–3.53) and magnesium intake (hazard ratio = 2.61; 95% CI = 1.42–4.79) compared with the highest quintile after adjusting for traditional cardiovascular disease risk factors. Similar inverse associations for total dietary fiber were also shown for vegetable fiber and fruit fiber. Conclusion: Lower magnesium, lower total dietary fiber intake, or lower intake of both was associated with higher risk of diabetes in the Taiwanese population. Clinical trials are required to confirm the protective effects of the adequate intake of fiber, magnesium, and/or their combination
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