CONTACT ACTIVATION OF PLASMATIC COAGULATION ON POLYMERIC MEMBRANES MEASURED BY THE ACTIVITY OF KALLIKREIN IN HEPARINIZED PLASMA

Kallikrein is involved in the generation of bradykinin during extracor poral circulation, that is believed to play an important role in cases of anaphylactic shock during hemodialysis. Therefore, a method for th e assessment of kallikrein generation was developed, based on the chro mogenic substrate S-2302. Comparison of kallikrein-like activity on gl ass using citrate or heparinized plasma demonstrated enhanced activity in the presence of heparin. The applicability of the assay, and the t ime course of kallikrein generation was demonstrated with glass and cu prophan. Membranes based on pure polyacrylonitrile, or its copolymers differing in their content of acrylic acid, 2-hydroxyethyl acrylate, a nd allylsulphonate were investigated with respect to kallikrein-like a ctivity, and physicochemical surface properties. It was found that hig h content in 2-hydroxyethyl acrylate, and acrylic acid caused a substa ntial activation of the contact system while low content in allylsulph onate (less than 2 mol%) did not result in enhanced kallikrein-like ac tivity. The activating materials were characterized to be highly wetta ble, and had the most negative zeta potentials.