Effect of UV-modified fibrinogen on platelet aggregation in platelet-rich plasma.

Oxidized UV-modified fibrinogen activates platelets in platelet-rich plasma. Kinetic turbidimetry showed that addition of oxidized fibrinogen to platelet-rich plasma led to platelet aggregation. Reversible aggregation is recorded starting from the 30th second and then constantly grows with the same rate. Nonoxidized fibrinogen produced no such effect. The relationship between aggregation intensity and rate and the degree of fibrinogen oxidation was described by a bell-shaped curve with a peak corresponding to 24% fibrinogen oxidation. The amplitude of aggregation increased with increasing the concentration of irradiated fibrinogen from 0.1 to 1.0 mg/ml and then plateaued. The rate of aggregation little depended on fibrinogen concentration.