BACKGROUND Monitoring patients on oral anticoagulation is essential to prevent hemorrhage and recurrent thrombosis. We studied tissue factor-induced whole-blood coagulation in patients on warfarin therapy with similar international normalized ratios (INRs). METHODS AND RESULTS Contact pathway-suppressed whole-blood coagulation initiated with tissue factor was studied in 8 male subjects (group...

Blood coagulation factor VIII is a glycoprotein cofactor that is essential for the intrinsic pathway of the blood coagulation cascade. Inhibitory antibodies arise either spontaneously or in response to therapeutic infusion of functional factor VIII into hemophilia A patients, many of which are specific to the factor VIII C2 domain. The immune response is largely parsed into "classical" and "non...

Von Willebrand factor (VWF) is a multimeric plasma glycoprotein that plays a central role in the initiation of blood coagulation. Through interactions between its specific functional domains, the vascular wall, coagulation factor VIII, and platelet receptors, VWF maintains hemostasis by binding to platelets and delivering factor VIII to the sites of vascular injury. In the healthy human populat...

A coagulation test abnormality, termed activated protein C (APC) resistance, involving poor anticoagulant response to APC is currently the most common laboratory finding among venous thrombophilic patients. Because the anticoagulant activity of APC involves inactivation of factors Va and Vllla, studies were made to assess the presence of abnormal factors V or VIII. Diluted aliquots of plasma fr...

We studied the activation of factor X by the intrinsic pathway of blood coagulation using a new assay of factor X activation. When factor X tritiated in its sialic acid residues is activated, activation can be measured by the release of tritiated activation peptide, and the initial rate of activation can be determined under varying conditions. In the presence of phospholipid and calcium ions, f...

Molecular defects in Factor VIII (FVIII), such as haemophilia A-related mutations or denaturative conformational changes, may affect the stability of FVIII as well as its interactions with physiological activators, von Willebrand Factor, phospholipid, or conformationally sensitive antibodies. We summarize the contemporary assays which allow identification of impaired functional interactions of ...

Factor V and factor VIII are homologous cofactors in the blood coagulation cascade that have the domain structure A1-A2-B-A3-C1-C2, of which the B domain has extensively diverged. In transfected COS-1 monkey cells, expression of factor VIII is approximately 10-fold less efficient than that of factor V, primarily because of inefficient protein secretion and, to a lesser extent, reduced mRNA expr...

Bone marrow transplantation (BMT) is nowadays used in various hematological disorders including leukemias. Hemophilia A is sex linked bleeding disorder in which there are various genetic abnormalities in factor VIII gene. Among various hematological disorders, bleeding disorders mainly hemophilia in now widely treated using plasma derived and recombinant factor VIII concentrates. Day to day tra...

INTRODUCTION Traumatic injuries are amongst the leading causes of death worldwide, frequently as a result of uncontrolled hemorrhage. Critical deficiencies in clotting factors have been noted in trauma-induced coagulopathy. However, the exact underlying conditions that result in devastating coagulopathies remain unclear. The purpose of this study was to elucidate these underlying deficiencies. ...

BACKGROUND Individuals with type O blood are more likely to have reduced factor VIII and von Willebrand factor levels compared to their non-O counterparts. Hydroxyethyl starch (HES), which is widely used for blood volume replacement, can induce coagulopathy. Therefore, we tested whether blood type O patients show more coagulopathy and blood loss than non-O patients after infusion of 6% HES. M...