The parameters of lipid peroxidation and enzymatic and low-molecular antioxidant systems of blood plasma were studied in 114 patients with insulin-dependent diabetes mellitus and 51 donors (control group). The activities of extracellular superoxide dismutase, catalase, concentrations of plasma selenium, the activity of red cell glutathione peroxidase, and the level of uric acid were measured. Oxidant stress was found to involve no changes of the enzymatic component of antiperoxide defense in

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... ients both at the debut of the disease and with diabetic angiopathies. Evidently, the cell protection is performed not by the enzymatic, but by the low-molecular antioxidant system. The level of total antioxidant activity of the plasma is increased in newly diagnosed diabetes and normalizes by the time of formation of microangiopathies. The concentration of uric acid - one of the plasma antioxidants - is reliably decreased in comparison with the control, which may be significant in the pathogenesis of microangiopathies.