The binding of factor VIII to von Willebrand factor (vWF) is essential for the protection of factor VIII against proteolytic degradation in plasma. We have characterized the binding kinetics of human factor VIII with vWF using a centrifugation binding assay. Purified or plasma vWF was immobilized with a monoclonal antibody (MoAb RU1) covalently linked to Sepharose (Pharmacia LKB Biotechnology, ...

Two forms of rabbit factor VIII procoagulant activity, distinguishable by size on gel filtration and ultracentrifugation, have been identified in normal rabbit plasma. These studies have been carried out with citrate-anticoagulated rabbit plasma obtained by cardiac puncture. Two peaks of factor VIII activity were obtained on agarose gel chromatography, using physiologic ionic strength buffers: ...

Variations of the partial thromboplastin time (PTT) were tested to determine the best screening method for detection of inhibitors of factor VIII. Variables tested included the duration of preincubation of a mixture of patient plasma and factor VIII source (normal plasma), the ratio of the patient plasma to the normal plasma, and the duration of incubation of the normal plasma-patient plasma mi...

1. Goudemand J, Rothschild C, Demiguel V, et al. Influence of the type of factor VIII concentrate on the incidence of factor VIII inhibitors in previously untreated patients with severe hemophilia A. Blood. 2006;107:46-51. 2. Chalmers EA, Brown SA, Keeling D, et al. Early factor VIII exposure and subsequent inhibitor development in children with severe haemophilia A. Haemophilia. 2007;13:149-15...

The development of inhibitory antibodies to factor VIII in patients affected by a mild form of hemophilia A (factor VIII > 0.05 IU/mL) is considered a rare event. In this study, we evaluated the relationship between genotype and anti-factor VIII antibody formation in a patient with mild hemophilia A. Mutation analysis showed that a missense mutation in the factor VIII gene leading to replacemen...

The possible role of Ca2+ as an essential constituent part of the human factor VIII complex has been investigated by stability studies, metal determinations, and gel filtration experiments. In citrated plasma, the factor VIII coagulant activity (VIII:C) deteriorated during storage in a biphasic manner. Collection of blood in heparin, instead of chelating anticoagulants, or neutralization of cit...

We investigated the activation of the nonenzymatic protein cofactors factor VIII and factor V in plasma when coagulation was initiated by thromboplastin. With sensitive bioassays, we were able to measure specifically the generation of activated factor VIII and activated factor V in plasma. Our results showed that when plasma was triggered with a relatively high concentration of thromboplastin, ...

The development of inhibitory antibodies to factor VIII in substitution was introduced into the cDNA encoding the A2 patients affected by a mild form of hemophilia A (factor VIII domain of factor VIII and the resulting construct was exÛ 0.05 IU/mL) is considered a rare event. In this study, we pressed in insect cells. Strikingly, the metabolically labeled evaluated the relationship between geno...

Fulminant hepatic failure (FHF) in humans produces a bleeding diathesis due in large part to a reduction in the biosynthesis of liver-derived coagulation factors. Remarkably, factor VIII procoagulant activity is elevated in most of these patients despite widespread liver cell death. FHF can be modeled in mice by administration of azoxymethane, the active ingredient found in cycad palm nuts. We ...