Methods for studying fibrinolytic pathway components in human plasma

Abstract

Methods have been developed to quantitatively measure the major plasma components of the human fibrinolytic system. Plasminogen is measured functionally with a 9M excess of streptokinase and immunochemically by rocket immunoelectrophoresis; the normal range was found to be 16.7–23.8 mg/dl and 17.4–21.6 mg/dl, respectively. α 2-plasmin inhibitor is measured functionally and immunochemically; the normal range for the major plasma plasmin inhibitor was found to be 5.30–6.60 mg/dl by both methods. Plasminogen activator concentrations, as well as, free, and complexed, protease activities are measured along with plasmin generation rates by spectrophotometric assays with chromogenic substrates. Both activator and free protease activities are zero in plasma samples from normal human subjects. Plasmin generation rates are 0.25–0.47% with urokinase and 5.30–9.70% with streptokinase; these values are the percentages of the respective initial velocities of activation in purified systems.