Activities of antiplasmin and antiplasminogen activator in serous middle ear effusions.

Antiplasmin and antiplasminogen activator activities in serous middle ear effusion (MEE) collected from adult patients were measured to analyze the kinetics of antifibrinolytic activity of protease inhibitors. No trypsin, plasmin, and plasminogen activator (PA) activity could be detected in the pooled serous MEE by either the fibrin plate method or the fluorometric assay. Antiplasmin activity in serous MEE was lower than that in plasma. The MEE had no antiurokinase activity. These findings indicate that 1) serous MEE has residual antifibrinolytic activity which may be attributed to mainly antiplasmin activity of unsaturated plasmin inhibitors and not to anti-PA activity, and 2) that serous MEE contains no secretory urokinase inhibitors.