Fibrinolytic activity of middle ear fluid in otitis media with effusion

In order to investigate the prolonged factors of otitis media with effusion, hydrolytic activities for specific substrates of plasmin and plasminogen activator (P.G.-activator) and the activity for fibrin degradation (fibrinolysis) were measured. Materials were middle ear fluids of 36 cases diagnosed as unilateral otitis media with effusion. Age of the patients were from 28 to 88 years old (mean: 61.3). Using specific substrates, determinations of P.G.-activator activity and plasmin activity were made by the method of Claeson et al. and fibrinolysis was determined by the standard fibrin plate. The results are shown below: 1) Both activities for decomposition of amide against the specific substrates of plasmin and of P.G.-activator were revealed. 2) Concerning fibrinolysis in all cases, we divided them into 3 groups; fibrinolysis (-) group of 8 cases (22.2%) which could not dissolve fibrin at all, fibrinolysis (+) group of 17 cases (47.2%) which could dissolve fibrin. Fibrinolysis (+/-) group of 11 cases (30.6%) of which the presence of fibrin dissolution was unknown. 3) The progress of fibrinolysis was observed by serial collection of middle ear fluid in the same side ear of 5 cases out of 17 cases having much activity for fibrin degradation, and lowering of fibrinolytic activity was revealed in 4 out of these 5 cases as the result. On the basis of these results, we discussed on the process of prolongation in this disease from the standpoint of the presence of fibrinolytic activity in the middle ear fluid.