To study the digestion pattern of human high-molecular weight (mol wt) kininogen (HMWK) in plasma during contact activation we have prepared monoclonal antibodies (MoAbs) to the light-chain (LC) and the heavy-chain moiety of HMWK. One MoAb from each set was purified, and neither MoAb inhibited the clotting activity of HMWK. In enzyme-linked immunosorbent assay and immunoblotting experiments nei...

We have generated a mouse where the clotting factor IX (FIX) gene has been disrupted by homologous recombination. The FIX nullizygous (-/-) mouse was devoid of factor IX antigen in plasma. Consistent with the bleeding disorder, the factor IX coagulant activities for wild-type (+/+), heterozygous (+/-), and homozygous (-/-) mice were 92%, 53%, and <5%, respectively, in activated partial thrombop...

Organ transplantation and perfusion studies indicate that the spleen plays an important role in the regulation of plasma levels of factor VIII-von Willebrand’s factor (FVlllvWF). To better understand the mechanisms that regulate the FVIII-vWF increases after infusion of 1 -deamino-8D-arginine vasopressin (DDAVP). we have measured factor VIII coagulant activity (FVIII:C) and antigen (FVIII:CAg) ...

1. A substance has been isolated from the venom of the Okinawan pit viper (Trimeresurus okinavensis) that causes the aggregation of human blood platelets. The reaction resembles that between platelets and thrombin or connective tissue, in that the platelets release ADP. 2. The purified venom fraction is a protein-polysaccharide, and after Pronase digestion had mol.wt. 4x10(6), containing 10% pe...

Interactions between the vessel wall and platelets or leukocytes were traditionally thought to be separate cellular adhesive contributions to either coagulation or inflammation. Platelets, in response to vessel wall injury, adhere to components of the extracellular matrix (ECM), which triggers sudden platelet activation and platelet plug formation. Initial responses are followed by coagulant ac...

Antibodies against factor VIII coagulant activity can appear in haemophiliacs who are treated with factor VIII preparations but also spontaneously in non-haemophiliacs. The Bethesda assay is the most commonly used method to detect these antibodies, but it lacks specificity especially in the lower range resulting in unreliable data. Two modifications are proposed and tested to resolve the imperf...