Inhibition of a Human Fibrinolytic System by Normal and Pathologic Sera

Abstract

A standardized, urokinase activated, human fibrinogen-plasminogen fibrinolytic system with an arbitrarily controlled lysis time of 13 [plus or minus] 1 minutes is described. Inhibition of this fibrinolytic complex by normal human serum was established. Study of sera from 32 patients with various diseases revealed 8 cases of serum inhibitor activity significantly above normal by the standardized assay. None of these had diseases in which there is considered to be abnormal accumulations of fibrin. In ancillary studies epsilon-amino-n-caproic acid was found to inhibit the assay system as, to a lesser degree, did serotonin and histamine; tolbutamide had no significant effect.