Botrocetin, originally called venom coagglutinin, is a Bothrops factor that causes aggregation of blood platelets in the presence of the von Willebrand component of the factor VIII macromolecular complex. The complex consists of a series of multimers with a molecular weight of about 1-20 x 10(6). Ristocetin, another agent that causes platelet aggregation dependent on von Willebrand factor, reac...

Immunohistochemical localization of factor VIII-related antigen was studied in human tissues obtained at autopsy or renal biopsy, umbilical cord vessels, smears of washed blood cells and cultured human endothelial cells. Factor VIII-related antigen was demonstrated in the vascular intima throughout the body and cells lining the sinusoids of the lymph node, spleen and liver by an indirect immuno...

Factor VIII, a protein cofactor involved in blood coagulation, functions in vitro on a phospholipid membrane surface to greatly increase the rate of factor X activation by factor IXa. Using gel filtration, rapid sedimentation, and resonance energy transfer we have studied the interaction of recombinant-derived human factor VIII with small and large unilamellar phospholipid vesicles composed of ...

Coagulation factor VIII (FVIII) inhibitors are the most severe complications of haemophilia A treatment. We studied the effect of a non-activated prothrombin concentrate (PCC) combined with FVIII in vitro. FVIII antibodies minimised the in vitro thrombin generation of standard human plasma and prolonged the lag phase at a residual FVIII activity of ≤ 0.01 IU/ml. Time to clotting of FVIII-inhibi...

If endotheiial injury plays a prominent role in early atherogenesis, the plasma levels of von Willebrand factor (VWF), which is made within and normally released from endotheiial cells, might be expected to rise as a marker of the cellular damage. To evaluate this hypothesis, we measured plasma VWF (as VIIIR Ag), factor VIII C, and serum lipids serially up to 37 weeks in 29 adult male cynomolgu...

An immunologic and virologic work-up was undertaken in 425 symptom-free multitransfused patients with hemophilias or hemoglobinopathies living in France. Patients were entered into five groups according to the type of blood product they received: local factor VIII, a mixture of local and imported factor VIII. imported factor IX. local factor IX, washed red blood cells. The overall prevalence of...

We describe a 19-year-old boy who was diagnosed with congenital thrombotic thrombocytopenic purpura (cTTP) at 7 months of age. He was subsequently treated with fresh frozen plasma infusions every 3 to 4 weeks for the next 15 years at which point he developed significant hypersensitivity reactions to fresh frozen plasma. He required immunosuppressive therapy with systemic desensitization in the ...

TO THE EDITOR: Combined factor V and VIII deficiency, a rare autosomal recessive coagulopathy, was first defined by Oeri et al. in 1954 [1]. Although it is seen worldwide, Mediterranean countries have higher prevalence rates [2]. The presentation varies from mild to serious bleeding symptoms such as easy bruising, menorrhagia, epistaxis, gingival bleeding, intramuscular bleeding, and post-opera...

Deficiencies of factor VIII (in haemophilia) and factor IX (in Christmas disease) prolong the partial thromboplastin time. If normal plasma is treated with alumina, the factor VIII remains but the factor IX is removed and can subsequently be recovered by elution of the alumina. If a long partial thromboplastin time is found on investigating a male patient whose history suggests a life-long blee...