Studies of the mechanisms of blood coagulation zymogen activation demonstrate that exosites (sites on the activating complex distinct from the protease active site) play key roles in macromolecular substrate recognition. We investigated the importance of exosite interactions in recognition of factor IX by the protease factor XIa. Factor XIa cleavage of the tripeptide substrate S2366 was inhibit...

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...

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...

We used recombinant DNA techniques to map a panel of six monoclonal antibodies (MoAbs) to regions of the human factor IX molecule. A-2 maps to 17 amino acids at the amino terminus of the heavy chain of IXa; 2D5, an inhibitor of clotting, is defined to 36 amino acids of the first EGF-like domain of human factor IX. A-4, A-5, C10D, and FXC008 all map to a region of the heavy chain containing amin...

The revised UKHCDO factor (F) VIII/IX Inhibitor Guidelines (2000) are presented. A schema is proposed for inhibitor surveillance, which varies according to the severity of the haemophilia and the treatment type and regimen used. The methodological and pharmacokinetic approach to inhibitor surveillance in congenital haemophilia has been updated. Factor VIII/IX genotyping of patients is recommend...

background: leukemia inhibitor factor (lif) is a very important pleiotropic cytokine which belongs to interleukin-6 (il-6) family. lif exerts multiple effects on different types of cells and tissues with numerous regulatory effects in vivo and in vitro. it is a lymphoid factor, which performs a number of activities including cholinergic neuron differentia­tion, control of stem cell pluripotency...

Factor XI deficiency, an injury-related bleeding disorder, is rare worldwide but common in Jews in whom 2 mutations, Glu117Stop (type II) and Phe283Leu (type III), prevail. Mean factor XI activities in homozygotes for Glu117Stop and for Phe283Leu are 1 and 10 U/dL, respectively. Inhibitors to factor XI in patients with severe factor XI deficiency have been reported in a small number of instance...

Factor XI deficiency, an injury-related bleeding disorder, is rare worldwide but common in Jews in whom 2 mutations, Glu117Stop (type II) and Phe283Leu (type III), prevail. Mean factor XI activities in homozygotes for Glu117Stop and for Phe283Leu are 1 and 10 U/dL, respectively. Inhibitors to factor XI in patients with severe factor XI deficiency have been reported in a small number of instance...

We report here the effect of activated human platelets on the activation of human factor IX by human factor XIa. Factor IXa formed during activation was determined via its ability to activate bovine factor X. To increase sensitivity, phospholipids and bovine factor VIIIa were present in the assay. The kinetic parameters of the factor IX activation were determined in the presence of 10 mmol/L Ca...