The clamps will simulate the possible attenuation or increase in endothelial reactivity promoted by the independent variables during ischemia/reperfusion (I/R) injury. In total, the test will consist of realization of a basal FMD-1 (during 15 minutes), clamps (variable length, usually 60 minutes), FMD-2 (15 min) after the clamp, rest time (30 min), ischemia/reperfusion (20 min) injury, rest time (15 min) and FMD-3 (15 min). Throughout the experiment, blood glucose and insulin will be controlled and maintained at levels such as designed previously for each clamp situation. In all subjects, plasma samples will be collected before the start of the clamp (during FMD-1), at the end of the measurement of the second FMD during the clamp, prior to the I/R injury and 15 minutes after the end of the same test (during FMD-3). In these samples will be dosed insulin, glucose, C-peptide, C-reactive protein, tumor necrosis factor-α (TNF-α), nitric oxide, intercellular adhesion molecule-1 (ICAM-1), plasminogen activator inhibition-1 (PAI-1), isoprostane and interleucin-1 (IL-1).