[Optimizing the fibrinogen-thrombin adhesive system]

It was the aim of the present three series of investigations to determine conditions to improve the firmness of the clot produced by the fibrinogen-thrombin adhesive system. For methodological reasons the compressive strength and adhesive power of the clot, as well as the probability of a relation between deformation energy and tensile strength were examined. Furthermore, the influence of fibrinolysis on the effects of the adhesive system was investigated. The following factors proved to be relevant for the firmness of the clot: 1. Concentration of fibrinogen, 2. concentration of thrombin, 3. relation between volume of fibrinogen and of thrombin solution, 4. time of diffusion of constituents of mixture, 5. addition of blood-clotting factor XIII and solution of calcium ions. The following optimum concentrations of components of the adhesive system per ml of the mixture were established in the course of the investigations: Fibrinogen solution (approx. 10% clottable material) 0.86 ml Thrombin 100 E. Factor XIII 90 E. = 30 mg Ca++ 250 mMol A volume ratio of 6 parts of fibrinogen as cryoprecipitate to 1 part of a solution containing thrombin, factor XIII and calcium ions proved optimal for the preparation of the mixture.