- Evaluation of the relationship between the development of renal failure and the activity of endogenous vasoactive systems: plasma renin activity, plasma concentration of aldosterone, noradrenaline, atrial natriuretic factor and nitrites. Evaluation of the relationship between the development of renal failure and the concentration of inflammatory cytokines: tumor necrosis factor-α, interleukin-6, interleukin-1, interleukin-10.