The thrombotic activity of activation product

Experimental venous thrombosis induced by homologous serum in the rat

To investigate the effects of new drugs on the prevention of venous thrombosis, the Wessler stasis model is extensively employed usually in the rabbit. In this model, a hypercoagulable state is achieved by the administration of either heterologous serum (often human serum) or an activated coagulation factor followed by total stasis of the vein in which the thrombus is to be formed. Although classically the stasis model is performed in rabbits, it is possible to induce experimental venous thrombosis in a number of animal species, including rats. However, the use of homologous serum as the activating or thrombogenic agent has been previously described only in the dog and in the rabbit. The purpose of the present study was to compare the activities of heterologous and homologous serum as hypercoagulating agents in a rat stasis model of venous thrombosis using Wessler's technique. Heparin was employed as a reference antithrombotic compound in order to compare the two thrombogenic challenges.

The multiple coagulopathies of biliary atresia

Detailed coagulation studies were done prospectively on 43 patients with biliary atresia who had undergone Kasai operation (hepatic portoenterostomy). Patients were divided into three groups based on levels of factor V, factor II, and Echis II and/or response to vitamin K: no coagulopathy (46.5% of patients); coagulopathy of liver disease (30.2% of patients); and coagulopathy of vitamin K deficiency (23.3% of patients). Patients with the coagulopathy of liver disease had significantly lower levels of factors XII, V, and antithrombin III as well as longer thrombin times than patients with no coagulopathy or vitamin K deficiency. Factor V levels were decreased only in patients with more advanced liver disease; normal levels of factor V were not usually helpful in differentiating liver disease and vitamin K deficiency. The prothrombin time, factor VII-X levels, and factor II levels were significantly different for all three groups; the most abnormal values occurred in the vitamin K-deficient group. Comparison of the Echis II level to factor II coagulant activity was helpful in deciding whether a coagulopathy was due to liver disease, vitamin K deficiency, or both. Factor VIII levels were elevated in all groups. Factor VIII coagulant activity was significantly higher by the two-stage (TGT) method than by the one-stage (PTT) method. Hypersplenism causing neutropenia and thrombocytopenia was commonly seen after the age of 5 years. Vitamin E deficiency was more common than vitamin K deficiency; however, all vitamin K-deficient patients were vitamin E deficient. Coagulation status correlated well with hepatobiliary scan data, but not serum bilirubin levels. Recommendations for treatment of patients with vitamin K deficiency and/or liver disease are discussed.

Clotting changes, including disseminated intravascular coagulation, during rapid renal-homograft rejection

One of two patients in whom early homograft rejection developed after renal transplantation had many antidonor antibodies before operation. By the measurement of gradients across intracorporeal and extracorporeal homografts in this patient, the new kidneys were shown to sequester host immunoglobulins, platelets, white cells and clotting factors. Moreover, the renal venous blood then contained fibrinolytic activity. This presensitized recipient, as well as a second patient who did not have detectable preformed humoral antibodies, gave evidence from clinical observation and from the various clotting tests of disseminated intravascular coagulation with fibrinolysis and a severe bleeding, diathesis. Immunofluorescent and histologic studies revealed a laying down of fibrin in the homograft vessels that continued in some cases to cortical necrosis of the transplanted kidneys or, alternatively, receded at the time fibrinolysis occurred. The variety of rejection seen in these patients has been characterized as an immunologically induced coagulopathy.

Intravascular coagulation secondary to cavernous hemangioma in infancy: response to radiotherapy

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THE ROLE OF LIPOPROTEINS IN THE PRODUCTION OF HYPERCOAGULABILITY: A NEW CONCEPT

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