Alberto O. Chávez

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beta-Cell dysfunction is an important factor in the development of hyperglycemia of type-2 diabetes mellitus, and pancreatic islet amyloidosis (IA) has been postulated to be one of the main contributors to impaired insulin secretion. The aim of this study was to evaluate the correlation of IA with metabolic parameters and its effect on islets of Langerhans(More)
Type 2 diabetes mellitus (T2DM) is characterized by defects in insulin action and insulin secretion. Although insulin resistance manifests early during the prediabetic state, a failing beta-cell function unable to overcome insulin resistance at target tissues determines the onset of T2DM. This review focuses on recent advances in the molecular mechanisms of(More)
BACKGROUND Several studies have associated elevated liver enzymes (LFTs), obesity, and type 2 diabetes (T2DM), and a link has been established between insulin resistance (IR) and elevated ferritin concentrations. We examined the relationship between LFTs, ferritin, and IR in morbid obese subjects and the effect of weight loss after bariatric surgery. (More)
CONTEXT Mitochondrial dysfunction has been proposed as an underlying mechanism in the pathogenesis of insulin resistance and type 2 diabetes mellitus. OBJECTIVE To determine whether mitochondrial dysfunction plays a role in the free fatty acid (FFA)-induced impairment in insulin action in skeletal muscle of healthy subjects. DESIGN Eleven lean normal(More)
Insulin resistance is a characteristic feature of type 2 diabetes and obesity. Insulin-resistant individuals manifest multiple disturbances in free fatty acid (FFA) metabolism and have excessive lipid accumulation in insulin target tissues. Although much evidence supports a causal role for altered FFA metabolism in the development of insulin resistance,(More)
OBJECTIVE Fibroblast growth factor (FGF)-21 is highly expressed in the liver and regulates hepatic glucose production and lipid metabolism in rodents. However, its role in the pathogenesis of type 2 diabetes in humans remains to be defined. The aim of this study was to quantitate circulating plasma FGF-21 levels and examine their relationship with insulin(More)
AIMS/HYPOTHESIS TNF-alpha levels are increased in obesity and type 2 diabetes. The regulation of TNF-alpha converting enzyme (TACE) and its inhibitor, tissue inhibitor of metalloproteinase 3 (TIMP3), in human type 2 diabetes is unknown. METHODS We examined TACE/TIMP3 regulation: (1) in lean and obese normal glucose tolerant (NGT) individuals and in type 2(More)
OBJECTIVE To assess the contribution of decreased glucose clearance to the rise in fasting plasma glucose (FPG) in the nondiabetic range. RESEARCH DESIGN AND METHODS A total of 120 subjects with normal glucose tolerance received an oral glucose tolerance test and euglycemic insulin clamp with 3-[(3)H]glucose. The basal and insulin-stimulated rates of(More)
OBJECTIVE To quantitate insulin sensitivity in lean and obese nondiabetic baboons and examine the underlying cellular/molecular mechanisms responsible for impaired insulin action to characterize a baboon model of insulin resistance. RESEARCH DESIGN AND METHODS Twenty baboons received a hyperinsulinemic-euglycemic clamp with skeletal muscle and visceral(More)
AIMS/HYPOTHESIS The aim of this study was to measure mitochondrial reactive oxygen species (ROS) production directly from skeletal muscle biopsies obtained from obese insulin-resistant non-diabetic and type 2 diabetic participants. METHODS Ten lean healthy, ten obese non-diabetic and ten type 2 diabetic participants received a(More)