Article
The product of triglycerides and glucose, a simple measure of insulin sensitivity. Comparison with the euglycemic-hyperinsulinemic clamp
Fecha
2014Autor
Moreno-Galindo, E.G.
Rodriguez-Elias, J.C.
Ramirez-Herrera, M.A.
Sanchez-Chapula, J.A.
Navarro-Polanco, R.A.
Institución
Resumen
The human intestinal pathogen Giardia lamblia is a flagellated unicellular protozoan with pronounced medical and biological relevance. However, the basic physiology of Giardia trophozoites has been sparsely studied, especially the electrical and ionic properties of their cellular membrane which are virtually unknown. In this study, we were able to record and characterize the macroscopic ionic currents of Giardia trophozoite membrane by electrophysiological methods of the patch clamp technique. Giardia trophozoites showed a high current density (?600 pA/pF at -140 mV) that was activated upon hyperpolarization. This current was carried by a chloride-selective channel (I Cl-G) and it was the most important determinant of the membrane potential in Giardia trophozoites. Moreover, this conductance was able to carry other halide anions and the sequence of permeability was Br->Cl-?I -?F-. Besides the voltage-dependent inward-rectifying nature of I Cl-G, its activation and deactivation kinetics were comparable to those observed in ClC-2 channels. Extracellular pH modified the voltage-dependent properties of I Cl-G, shifting the activation curve from a V 1/2=-79 1 mV (pH 7.4) to -93 2 mV (pH 8.4) and -112 2 mV (pH 5.4). Furthermore, the maximal amplitude of I Cl-G measured at -100 mV showed dependence to external pH in a bell-shaped fashion reported only for ClC-2 channels. Therefore, our results suggest that I Cl-G possesses several functional properties similar to the mammalian ClC-2 channels. " 2013 Springer-Verlag.",,,,,,"10.1007/s00424-013-1350-9",,,"http://hdl.handle.net/20.500.12104/45245","http://www.scopus.com/inward/record.url?eid=2-s2.0-84901945331&partnerID=40&md5=d51e1ceb5d846629d432d8d0e8aad2ce",,,,,,"5",,"Pflugers Archiv European Journal of Physiology",,"915 924",,"466",,"Scopus WOS",,,,,,"Chloride channels; Giardia lamblia; Patch clamp",,,,,,"The principal conductance in Giardia lamblia trophozoites possesses functional properties similar to the mammalian ClC-2 current",,"Article"
"47029","123456789/35008",,"Guerrero-Romero, F., Biomedical Research Unit, Mexican Social Security Institute, 34000 Durango, Mexico, Research Group on Diabetes and Chronic Illnesses, 34000 Durango, Mexico; Simental-Mendía, L.E., Biomedical Research Unit, Mexican Social Security Institute, 34000 Durango, Mexico, Research Group on Diabetes and Chronic Illnesses, 34000 Durango, Mexico; González-Ortiz, M., Medical Research Unit in Clinical Epidemiology, West National Medical Center, Mexican Social Security Institute, 44380 Guadalajara, Mexico, Cardiovascular Research Unit, Physiology Department, University of Guadalajara, 44340 Guadalajara, Mexico; Martínez-Abundis, E., Medical Research Unit in Clinical Epidemiology, West National Medical Center, Mexican Social Security Institute, 44380 Guadalajara, Mexico, Cardiovascular Research Unit, Physiology Department, University of Guadalajara, 44340 Guadalajara, Mexico; Ramos-Zavala, M.G., Medical Research Unit in Clinical Epidemiology, West National Medical Center, Mexican Social Security Institute, 44380 Guadalajara, Mexico; Hernández-González, S.O., Medical Research Unit in Clinical Epidemiology, West National Medical Center, Mexican Social Security Institute, 44380 Guadalajara, Mexico; Jacques-Camarena, O., Medical Research Unit in Clinical Epidemiology, West National Medical Center, Mexican Social Security Institute, 44380 Guadalajara, Mexico; Rodríguez-Morán, M., Biomedical Research Unit, Mexican Social Security Institute, 34000 Durango, Mexico, Research Group on Diabetes and Chronic Illnesses, 34000 Durango, Mexico",,"Guerrero-Romero, F. Simental-Mendia, L.E. Gonzalez-Ortiz, M. Martinez-Abundis, E. Ramos-Zavala, M.G. Hernandez-Gonzalez, S.O. Jacques-Camarena, O. Rodriguez-Moran, M.",,"2010",,"Context: To meet the worldwide challenge of emerging diabetes, accessible and inexpensive tests to identify insulin resistance are needed. Objective: To evaluate the sensitivity and specificity of the product of fasting, we compared the triglycerides and glucose (TyG) index, a simple measure of insulin resistance, with the euglycemichyperinsulinemic clamp test. Design and Setting: We conducted a cross-sectional study of the general population and outpatients of the Internal Medicine Department at the Medical Unit of High Specialty of the Specialty Hospital at the West National Medical Center in Guadalajara, Mexico. Patients: Eleven nonobese healthy subjects, 34 obese normal glucose tolerance individuals, 22 subjects with prediabetes, and 32 diabetic patients participated in the study. Intervention: We performed a euglycemic-hyperinsulinemic clamp test. Main Outcome Measures: Sensitivity and specificity of the TyG index [Ln(fasting triglycerides) (mg/dl) x fasting glucose (mg/dl)/2] were measured, as well as the area under the curve of the receiver operating characteristic scatter plot and the correlation between the TyG index and the total glucose metabolism (M) rates. Results: Pearson's correlation coefficient between the TyG index and M rates was -0.681 (P < 0.005). Correlation between the TyG index and M rates was similar between men (-0.740) and women (-0.730), nonobese (-0.705) and obese (-0.710), and nondiabetic (-0.670) and diabetic (-0.690) individuals. The best value of the TyG index for diagnosis of insulin resistance was 4.68, which showed the highest sensitivity (96.5%) and specificity (85.0%; area under the curve + 0.858). Conclusions: The TyG index has high sensitivity and specificity, suggesting that it could be useful for identification of subjects with decreased insulin sensitivity. Copyright " 2010 by The Endocrine Society.