Biochemical properties of the fibrinogen component of a fibrin glue beforeand after severe dry heat treatment

Functional biochemical properties of 5 batches of the fibrinogen component of a fibrin glue produced by the ZLB Central Laboratory, Bern, each consist ing of 4 different in-process samples (taken after the first and second pre cipitation step, lyophilization, and dry-heat treatment) were studied in vi tro. We focused our attention on the effect of the anti-viral treatment of the lyophilized product by dry heat for 1 h at 100 degrees C. A slight redu ction in maximal turbidity of all heat-treated samples was observed during the clotting assay compared to nontreated samples. Treatment with dry heat did not result in generation of fibrinogen fragments that might accelerate tissue-plasminogen-activator (t-PA)-enhanced plasminogen to plasmin convers ion. The time course of fibrin cross-linking by factor XIII showed no diffe rences between heated and unheated samples. This result indicates that expo sure of the fibrinogen component to severe heat neither reduced activity of factor XIIIa nor affected the correct alignment of cross-linking sites in polymerized fibrin. Incubation of fibrinogen with thrombin, plasminogen, an d t-PA resulted in a slightly enhanced degradation of fibrin derived from t he heat-treated samples. The amount of residual moisture, determined to be within the range of 0.6-2.1% before heat treatment, did not influence clott ing, crosslinking, and fibrinolysis parameters. In conclusion, the virus in activation treatment by dry heat for 1 h at 100 degrees C induces no signif icant alterations of the in vitro biochemical properties of the fibrinogen component of this fibrin glue. (C) 2000 John Wiley & Sons, Inc.