The structure of soluble fibrin complexes and fibrin degradation products after Echis carinatus bite.

Studies on the concentration and structure of fibrinogen, fibrinogen-fibrin soluble complexes, and fibrinogen-fibrin degradation products were made on 11 patients in Nigeria who suffered defibrination following Echis carinatus bite. Following admission, before treatment with antivenom, all patients had reduced or zero fibrinogen levels, and increased concentrations of soluble complexes and degradation products. The fibrin component of the soluble complexes, separated by fibrinogen-sepharose chromatography, consisted of both intact fibrin and fibrin degraded at the alpha-chain. After isolation by Biogel chromatography the soluble complexes were also found to contain gamma-dimer chains. The fibrinogen-fibrin degradation products consisted of several X species, Y, D and D-dimer, as well as fragment E. The major fragment in all patients was D, but a few samples contained significant quantities of D-dimer, indicating in vivo activation of factor XIII. There was evidence of degraded fibrinogen, as well as fibrin, in the soluble complexes and degradation products, suggesting that fibrinogenolysis, in addition to fibrinolysis, had occurred, probably as a result of secondary endogenous activation of the fibrinolytic system in response to defibrination.