The complement protein C4b-binding protein plays an important role in the regulation of the protein C anticoagulant pathway. C4b-binding protein can bind to protein S, thereby inhibiting the cofactor activity of protein S for activated protein C. In this report, we describe a new role for C4b-binding protein in coagulation. We observed inhibition of the intrinsic factor X activating reaction by...

To understand why this quest was so prolonged, one needs to go back to the technologies of the 1970s and 1980s. Factor VIII is a cofactor for conversion of factorX to factorXa by activated factor IX and is the rarest of all the clotting factors in blood. Not surprisingly, it was the last but one of the classical blood coagulation factors to yield to the advance of molecular biology (in 1984, 2 ...

The rising incidence of neutralizing antibodies (inhibitors) against therapeutic factor VIII prompted the conduct of studies to answer the question as to whether this rise is related to the introduction of recombinant factor VIII products. The present article summarizes current opinions and results of non-clinical and clinical studies on the immunogenic potential of recombinant compared to plas...

A localized and regulated cascade of proteolytic events is a prerequisite for normal haemostasis. The activation of factor X by activated factor IX (factor IXa) in the presence of activated factor VIII (factor VIIIa) is essential for the formation of a fibrin clot at sites of vascular injury. We observed sustained activation of factor X on the surface of vascular endothelial cells, whereas, in ...

Factor VIII binds to phosphatidylserine (PS)-containing membranes through its tandem, lectin-homology, C1 and C2 domains. However, the details of C1 domain membrane binding have not been delineated. We prepared 4 factor VIII C1 mutations localized to a hypothesized membrane-interactive surface (Arg2090Ala/Gln2091Ala, Lys2092Ala/Phe2093Ala, Gln2042Ala/Tyr2043Ala, and Arg2159Ala). Membrane bindin...

BACKGROUND AND OBJECTIVES High levels of factor VIII are a common risk factor for venous thromboembolism (VTE). The aim of this study was to evaluate the possible interaction between the presence of high factor VIII levels and oral contraceptive (OC) use. DESIGN AND METHODS Factor VIII levels were measured by a chromogenic assay in 174 women who suffered from VTE in reproductive age and in 48...

An autosomally transmitted bleeding diathesis sharing some, but not all, features previously described in von Willebrand's disease (vWd) was studied in five patients representing three generations of a single family. Bleeding times in the upper normal range in conjunction with low-normal platelet counts, normal factor VIII coagulant activity and VIII-related antigen, decreased VIII-ristocetin c...

Coagulation is triggered during the onset of myocardial infarction, resulting in vascular occlusion. However, a causal role for individual haemostatic factors in the development of thrombotic occlusion is not established. Three cases (all relatively young women) are reported of raised factor VIII associated with myocardial infarction. Two patients presented acutely with myocardial infarction at...

Apparently quiescent, nonapoptotic endothelial cells mediate the activation of factor X by activated factor IX in the presence of its cofactor, activated factor VIII. In a previous study, we reported that during the activation of factor X, the interaction of the cofactor with the endothelial cell membrane clearly differs from the interaction of the cofactor with artificial lipid membranes. In t...