1,720,976 research outputs found
Static, but Non Dynamic, ß-Cell Responsiveness to Glucose Is Affected by the Risk Variant rs7903146 of TCF7L2 and Associated with a Delayed Time-to-Glucose-Peak in Obese Youths
No full textTrajectories of changes in glucose tolerance in a multiethnic cohort of obese youths: an observational prospective analysis
No full textEthnicity and Common Genetic Variants Modulate Nonalcoholic Fatty Liver Disease (NAFLD) Metabolic Phenotype in Obese Youth
No full textEthnic differences in lipoprotein subclasses in obese adolescents: importance of liver and intraabdominal fat accretion
No full textBackground: Recently, the deleterious metabolic effects of visceral fat [visceral adipose tissue (VAT)] deposition were challenged, and liver fat emerged as having a key independent role in the modulation of cardiometabolic risk factors. Objective: We explored the relation between liver fat content and VAT in 3 ethnic groups and evaluated whether the ethnic differences in the distributions of lipoprotein concentrations and sizes were associated with the hepatic fat fraction (HFF), VAT, or both. Design: In a multiethnic group of 33 white, 33 African American, and 33 Hispanic obese adolescents with normal glucose tolerance, we measured VAT and HFF by using magnetic resonance imaging. Fasting lipoprotein particle number and size were measured by using nuclear magnetic resonance spectroscopy. To assess the association between VAT and HFF, we categorized VAT into tertiles. Results: In each ethnic group, HFF values increased between successive tertiles of VAT. After multivariate adjustment and in comparison with the 2 other groups, African Americans showed lower triglyceride (P = 0.001) and higher HDL (P = 0.03) concentrations, lower concentrations of total (P = 0.007), large (P = 0.005), and medium (P lt 0.0001) VLDL, but higher concentrations of large HDL particles (P = 0.01) and larger HDL (P = 0.005). In multivariate linear models, independent of ethnicity, VAT was a significant predictor for large HDL (P = 0.003) and total small LDL (P = 0.001) concentrations, whereas HFF significantly predicted large VLDL (P = 0.03) concentrations. Conclusion: Liver fat accretion, independent of VAT, may play a role in the ethnic differences seen in large VLDL particles. This trial was registered at clinicaltrials.gov as NCT00536250
A Reduced Incretin Effect Mediated by the rs7903146 Variant in the TCF7L2 Gene Is an Early Marker of β-Cell Dysfunction in Obese Youth
Full text linkThe risk genotype for the common variant rs7903146 of the transcription factor 7-like-2 (TCF7L2) gene has been found to affect the incretin response in healthy and obese adults; however, whether a similar functional defect is also present in obese adolescents remains unexplored. Herein, we examined the functional effect of the rs7903146 variant in the TCF7L2 gene on the incretin effect and determined its translational metabolic manifestation by performing deep phenotyping of the incretin system, β-cell function relative to insulin sensitivity, the gastrointestinal-induced glucose disposal (GIGD) in obese youth with normal and impaired glucose tolerance
Central Role of Fatty Liver in the Pathogenesis of Insulin Resistance in Obese Adolescents
No full text
OBJECTIVE
We evaluated the role of fatty liver in the alteration of insulin sensitivity and β-cell function in two groups of obese adolescents, differing in hepatic fat content (hepatic fat fraction [HFF]) but with similar intrabdominal intramyocellular lipid content (IMCL) and overall degree of obesity.
RESEARCH DESIGN AND METHODS
We studied 23 obese adolescents with high HFF (HFF >5.5%) and 20 obese adolescents with low HFF (HFF <5.5%), matched for age, Tanner stage, BMI z score, and percentages of body fat, visceral fat, and IMCL. All subjects underwent an oral glucose tolerance test and a two-step hyperinsulinemic-euglycemic clamp, magnetic resonance imaging and 1H nuclear magnetic resonance to assess abdominal fat distribution, HFF, and IMCL, respectively.
RESULTS
The high HFF group showed significantly lower whole-body insulin sensitivity index (P = 0.001) and estimates of insulin secretion (P = 0.03). The baseline hepatic glucose production (EGP) rate was not different between the two groups. Suppression of EGP was significantly lower (P = 0.04) in the high HFF group during low-dose insulin; no differences were observed during the second step. Baseline fatty acids, glycerol concentrations, and clamp suppression of glycerol turnover did not differ between the groups. During the second step, the glucose disposal rate was significantly lower (P = 0.01) in the high HFF group.
CONCLUSIONS
Fatty liver, independent of visceral fat and IMCL, plays a central role in the insulin-resistant state in obese adolescents.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Lower Insulin Clearance parallels a reduced insulin sensitivity in obese youths and is associated with a decline in β-cell function over time
No full textWe examined the relationship between insulin clearance, insulin sensitivity and β-cell function and the longitudinal effect of insulin clearance on β-cell function in lean, obese insulin sensitive and insulin resistant adolescents.A hyperinsulinemic-euglycemic and a hyperglycemic clamp were performed in 110 youths to quantify hepatic and peripheral clearance, insulin sensitivity and β-cell function (disposition index, DIh-clamp). Participants underwent an OGTT at baseline and after 2 years to assess glucose tolerance and oral β-cell function (oDIcpep) and were sorted into four groups (lean, obese NGT insulin sensitive and resistant, obese IGT). Insulin sensitivity was defined based on the median of insulin stimulated glucose disposal (M) measured during the hyperinsulinemic- euglyemic clamp.Lean and obese insulin sensitive participants did not differ with respect to hepatic and peripheral clearance, nor for insulin sensitivity. Insulin sensitivity was linearly correlated with whole body insulin clearance. Hepatic insulin extraction at baseline acted as independent determinant of β-cell function at follow-up.The decline in insulin sensitivity, even in the absence of an impairment of glucose tolerance, is associated with lowering of hepatic insulin clearance in obese youth, that in turn may contribute to the decline in β-Cell function over time
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