DEVELOPMENT OF INCREASED FACTOR VII ACTIVITY DURING THE SPONTANEOUS COAGULATION OF BLOOD

Abstract

The develop-ment of increased Factor VII activity was studied during the clotting of normal and factor-deficient blood in the presence and absence of tissue thromboplastin. A standard, specific assay utilized Factor VII-deficient substrate plasma. Results of 5 normals were compared with 1 Factor V-, 1 Factor VII-, 5 Factor VIII-, 5 Factor DC-, 1 PTA-deficient, and 3 thrombocytopenic patients. Studies were performed on lyophilized Hageman- and Factor X-deficient sera, since specifically deficient patients were not available for study. It was shown that the development of increased Factor VII activity was not due to non-specific reactions nor was it caused by direct glass activation. In the absence of tissue thromboplastin, the developed activity was found to depend upon the presence of Hageman, PTA, Factors VII, VIII, and DC, and calcium. Platelets, Factor V, and Factor X did not appear to be necessary for the reaction. In the absence of tissue thromboplastin the development of increased Factor VII activity appears to depend upon certain factors which are necessary for plasma thromboplastin formation.