Abstract
1. It was suggested that the cytotoxic damage of bone marrow cells due to endotoxin is responsible for the induction of procoagulant activity of the cells, since a) bone marrow cells of mouse given endotoxin (Post-LPS-cells) had a significant procoagulant activity and time course of procoagulant induction in the cells was the same as those of cytotoxicity and decrease of nucleated cell numbers in the marrow, b) there existed a definite correlation between cytotoxicity and procoagulant activity, and c) the strong cytotoxic changes independent of endotoxin, i. e. after death did not induce a significant procoagulant activity.
2. The procoagulant activity of Post-LPS-cells was not considered to be endotoxin contaminated in the cells but to be tissue thromboplastin, since a) a large amount of endotoxin was required for direct activation of plasma clotting, and dose-response-regression line for endotoxin was not parallel to that for Post-LPS-cells, b) parallelism between the two regression lines for Post-LPS-cells and thromboplastin was recognized, and c) Post-LPS-cells did not shorten the clotting time of plasma deficient in factor VII but did in factor XII, as thromboplastin did.
3. While Post-LPS-cells corrected the prolonged clotting time of factor VIII deficient plasma, it was shown, utilizing a parallel line assay, that no factor VIII clotting activity was present in the cells.
It should be mentioned that the bone marrow cells are one of the sources of procoagulant induction, and Post-LPS-cells either in marrow or circulation would cause DIC in endotoxicosis.
