Changes of prekallikrein in the cases with disseminated intravascular coagulation syndrome

Changes of prekallikrein in the cases with DIC were investigated, i.e., DIC cases including disseminated metastasis of gastric cancer, acute promyelocytic leukemia and endotoxin shock. Therefore, the trigger substances for this paper were the pathologic cells of the leukemia, the cultured well differentiated adenocarcinoma cells and endotoxin. (1) The lysates of the pathologic cells of the leukemia and the cultured cells showed prekallikrein activation. Endotoxin showed prekallikrein activation via factor XII. (2) Serine proteases (factor Xa, thrombin, plasmin and trypsin) activated prekallikrein in the plasma and the purified prekallikrein. (3) Antithrombin III, aprotinin and FOY inhibited prekallikrein activation. Antithrombin III was promoted by heparin in its inhibitory effect.