We report a study on the importance of factor IX activation in thromboplastin-dependent coagulation in plasma. Diluted, CaCl2-containing thromboplastin solutions at constant phospholipid concentration were used to trigger the coagulation in plasma from patients with congenital factor IX and factor VIII deficiency in the presence and absence of added factors IX and VIII, and the generation of th...

background: hemophilia b is an x-linked recessive coagulation disorder caused by factor ix deficiency.  analysis of factor ix gene polymorphisms is considered the best approach for prenatal diagnosis and carrier detection of hemophilia b where the identification of gene mutation is not easily possible.   objective: to study the frequency of three factor ix-linked restriction fragment length pol...

Bovine factor IX (Christmas factor) is a coagulation protein present in plasma in a precursor or inactive form. It is a glycoprotein (M, = 55,000) composed of a single polypeptide chain. Factor IX in the presence of calcium ions is converted to factor IX, by factor XI, (activated plasma thromboplastin antecedent) or a protease present in Russell’s viper venom. The activation of factor IX by the...

background: factor viii inhibitor is one of the most problems in the treatment of hemophilia. patients with hemophilia who have inhibitors are capable of severe hemorrhage and treatments of these patients are more expensive and more difficult than those patients without inhibitor. the aim of present study was to determine the prevalence of inhibitor and to assess the necessity of screening of t...

Hemophilia B is an X-chromosomal recessive disease due to deficiency of coagulation factor IX. Three monoclonal antibodies against factor IX were prepared and used to develop immunoradiometric assays (IRMAs) of factor IX antigen (IX-Ag). IX-Ag was measured in 65 normal individuals with one IRMA based on polyclonal anti-IX antibodies and two IRMAs based on three monoclonal anti-IX antibodies. On...

We have studied the interaction between purified human factor XIa and antithrombin in the presence and absence of well-characterized preparations of heparin. The concentrations of hemostatic enzyme, protease inhibitor, and mucopolysaccharide were 5.76 X 10(-8) mol/L, 5.76 X 10(6) mol/L, and either 5.88 X 10(6) mol/L or 0, respectively. Kinetic investigation of this process using a tritiated fac...

Bovine factor IX (Christmas factor) is a coagulation protein present in plasma in a precursor or inactive form. It is a glycoprotein (M, = 55,000) composed of a single polypeptide chain. Factor IX in the presence of calcium ions is converted to factor IX, by factor XI, (activated plasma thromboplastin antecedent) or a protease present in Russell’s viper venom. The activation of factor IX by the...

Endothelium provides a specific binding site for Factor IX/IXa which can propagate activation of coagulation by promoting Factor IXa-VIII-mediated activation of Factor X. In this report the endothelial cell Factor IX/IXa binding site has been identified and the coagulant function of the receptor blocked. Studies using [3H]Factor IX derivatized with the photoaffinity labeling agent N-succinimidy...

Coagulation factor replacement therapy for the X-linked bleeding disorder hemophilia is severely complicated by antibody ("inhibitor") formation. We previously found that oral delivery to hemophilic mice of cholera toxin B subunit-coagulation factor fusion proteins expressed in chloroplasts of transgenic plants suppressed inhibitor formation directed against factors VIII and IX and anaphylaxis ...