Context:The metabolic syndrome, characterized by central obesity with dyslipidemia, hypertension, and hyperglycemia, identifies people at high risk for type 2 diabetes.Objective: Our objective was to determine how the insulin resistance of the metabolic syndrome is related to muscle fiber composition.Design: Thirty-nine sedentary men and women (including 22 with the metabolic syndrome) had insulin responsiveness quantified using euglycemic clamps and underwent biopsies of the vastus lateralis muscle. Expression of insulin receptors, insulin receptor substrate-1, glucose transporter 4, and ATP synthase were quantified with immunoblots and immunohistochemistry.Participants and Setting: Participants were nondiabetic, metabolic syndrome volunteers and sedentary control subjects studied at an outpatient clinic.
Main Outcome Measures:Insulin responsiveness during an insulin clamp and the fiber composition of a muscle biopsy specimen were evaluated.Results: There were fewer type I fibers and more mixed (type IIa) fibers in metabolic syndrome subjects. Insulin responsiveness and maximal oxygen uptake correlated with the proportion of type I fibers. Insulin receptor, insulin receptor substrate-1, and glucose transporter 4 expression were not different in whole muscle but all were significantly less in the type I fibers of metabolic syndrome subjects when adjusted for fiber proportion and fiber size. Fat oxidation and muscle mitochondrial expression were not different in the metabolic syndrome subjects.
Conclusion:Lower proportion of type I fibers in metabolic syndrome muscle correlated with the severity of insulin resistance. Even though whole muscle content was normal, key elements of insulin action were consistently less in type I muscle fibers, suggesting their distribution was important in mediating insulin effects. ) has more than doubled since 1980 (1). Because of obesity-related illness, the average life expectancy in the United States may soon decline for the first time (2). The metabolic syndrome is a precursor to the development of overt diabetes (3). Insulin resistance and hyperinsulinemia are key elements of the metabolic syndrome that is characterized by visceral obesity, hypertension, hyperlipidemia, hyperglycemia, coronary heart disease, and increased mortality (4). The severity of insulin re- Abbreviations: BMI, body mass index; GIR, glucose infusion rate; GLUT4, glucose transporter 4; IRS-1, insulin receptor substrate-1; SSGIR, steady-state glucose infusion rate; VO 2 max, maximal oxygen consumption.
Anaplasma species are tick-transmitted pathogens that impact veterinary and human health. Sicily is one of the locations where these pathogens are endemic. Sicily represents a typical Mediterranean ecosystem to study Anaplasma infection and tick habitat suitability. The aims of this study were (i) to characterize by 16S rRNA and species-specific msp4 gene PCR the prevalence and genotypes of A. marginale, A. phagocytophilum, and A. ovis in the most abundant host species in Sicilian provinces and (ii) to correlate differences between hosts and between western and eastern Sicily with the habitat suitability for ticks in these regions. Differences were found in the prevalence of Anaplasma spp. between different hosts and between western and eastern provinces. The differences in Anaplasma prevalence between different hosts may be explained by pathogen host tropism. The differences between western and eastern provinces correlated with the tick habitat suitability in these regions. The analysis of Anaplasma genotypes suggested a higher host and regional specificity for A. phagocytophilum than for A. marginale and A. ovis strains, a finding probably associated with the broader host range of A. phagocytophilum. The presence of identical A. marginale genotypes in the two regions may reflect cattle movement. The results for A. ovis suggested the possibility of some genotypes being host specific. These results provide information potentially useful for the management of tick-borne diseases caused by Anaplasma spp. in Sicily and other Mediterranean regions and may contribute to the development of models to predict the risks for these tick-borne pathogens.
Parasitic gastroenteritis is one of the major causes of productivity loss in sheep and goats. This report records two studies of the helminth fauna from post-mortem examination. The first study, performed on the digestive tract of 72 sheep from a central part of Sicily in a high hill village (1,360 meters above sea level), between April 1996 and March 1997, showed an infection rate of 78%. The second study targeted goats from the western part of Sicily and showed an infection rate of 90%. For sheep, a total of 23 species of helminths were identified belonging to the family of Trichostrongyloidea, with the genera Haemonchus, Ostertagia (Teladorsagia), Trichostrongylus, Cooperia, and Nematodirus; Strongilolidea with the genera Oesophagostomum and Chabertia: Ancylostomidea with Bunostomum; and Tricuridea with Tricuris. Teladorsagia circumcincta was the most common in the sheep abomasum, Bunostomum trigonocephalum and Trichostrongylus spp. in the small intestine, and Chabertia ovina and Trichuris ovis in the large intestine. For goats, a total of 12 species were isolated in the abomasum with Teladorsagia circumcincta and Trichostrongylus axei the most common species. In the small intestine, five species were isolated and Trichostrongylus capricola was the dominant species. T. ovis and O. venulosum were dominant in large intestine and in the cecum. We also found species belonging to other ruminants such as O. ostertagi (in cattle) and S. kolchida and O. leptospicularis (in wild ruminants).
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