[Clinical and experimental studies of septic DIC in surgical patients, in terms of its characteristic features and pathogenesis].

I have experienced 35 cases of DIC in my department during last 8 years. These cases were divided into a septic and non-septic groups based on their back-ground, and compared their clinical symptoms and various laboratory findings. The results showed the septic DIC group could be characterized as follows: (1) impairment of the vital organs was more clearly manifested, while hemorrhagic symptoms were mild, (2) the laboratory tests showed almost no tendency for fibrinogen or alpha 2-PI to be decreased or PIC to be increased, (3) the blood PAF (Platelet Activating Factor) level was clearly higher and showed an inverse relationship with the platelet count. On the basis of these clinical findings, I speculated septic DIC involves suppression of secondary fibrinolysis and participation of PAF. In experiment A, I investigated the effects of endotoxin (Et) on the activity of plasminogen activator (PA) in the rabbit renal cortex. In both in vitro and in vivo systems, I could demonstrate the renal cortex PA activity was significantly suppressed by Et. Then, in experiment B, I could confirm, (1) PAF caused a drop in the blood pressure and a decrease in the platelet count that were similar to those induced by Et, and that Et caused a decrease in the platelet count that was inversely accompanied by an increase in PAF, (2) PAF antagonist showed greater efficacy than a protease inhibitor in suppressing the decrease in the blood platelet count.