Abstract
The role of plasma fibrinogen in the formation of the stasis thrombus of the jugular vein and experimental thrombus of the femoral artery was studied in dogs. Marked hypofibrinogenemia was induced in the dogs 9 to 48 hours after the subcutaneous injection of defibrase, without any significant changes in platelet count and plasma coagulation factors except for fibrinogen. The score of the stasis thrombus was determined according to Wessler's standard. No thrombi were found in the jugular veins of five control dogs injected with normal saline alone. Thrombi were formed in all of the nine control dogs injected with 40ml of normal canine serum containing 20mg of watersoluble ellagic acid. In the eleven dogs with less than 65mg/dl of plasma fibrinogen concentration no thrombi developed following iv injection with serum and ellagic acid. Thrombi of score 2 to 4 were formed in eight dogs with fibrinogen concentration more than 120mg/dl after iv injection with serum and ellagic acid. In dogs with fibrinogen concentration 80-105mg/dl, thrombi of score 0-3 were observed.
The occluding thrombus was produced in all of control dogs on the chemically intimectomized femoral artery with stenosing ligature after iv injection with serum and ellagic acid. No thrombi developed in all of five defibrase injected dogs with fibrinogen concentration less than 60mg/dl on similary treated femoral artery following iv injection with serum and ellagic acid. Occluding thrombus was formed in 7 out of the 9 defibrase treateed dogs with fibrinogen concentration of 80-255mg/dl. From the results above described, it is suggested that plasma fibrinogen concentration more than 80mg/dl is essential for the formation of either stasis thrombus or experimental occluding arterial thrombus.
