title: Demonstration of 99mTc-labelled plasmin on the surface of ex vivo thrombi.
abstract: In an vitro system using the Chandler model for the preparation of in vitro thrombi trace amounts of porcine or human 99mTc-labelled plasmin was found to adsorb to the surface of a preformed thrombus. A radioactive lining of the thrombus could be demonstrated using autoradiography after addition of 99mTc-labelled plasmin in concentrations of 0.04 - 0.07 or 0.4 - 0.7 CTA u/thrombus made from 2 ml whole blood (0.035 - 0.35 microM). The same pattern was found for porcine as for human plasmin. The presence of tranexamic acid in concentrations of 3 to 12 mM did not affect the binding of plasmin indicating that the plasmin binding to fibrin was independent of the lysine binding sites. Furthermore alpha 2-antiplasmin was demonstrated on/in the thrombus also when no plasmin was present indicating a binding of alpha 2-antiplasmin to the thrombus. The plasmin bound to the thrombus was proteolytically inactive. In order to obtain thrombolysis most of the alpha 2-antiplasmin in the surrounding medium had to be neutralized.
mesh_terms: D000818:Animals; D001345:Autoradiography; D005341:Fibrinolysin / Q000032:analysis*; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D013670:Sodium Pertechnetate Tc 99m; D013552:Swine; D013667:Technetium; D013927:Thrombosis / Q000097:blood*; D000979:alpha-2-Antiplasmin / Q000032:analysis; D000511:alpha-Macroglobulins / Q000032:analysis
chemical_list: D000979:alpha-2-Antiplasmin; D000511:alpha-Macroglobulins; D013667:Technetium; D013670:Sodium Pertechnetate Tc 99m; D005341:Fibrinolysin