based on epidemiologic data, women who take oral contraceptives seem to have an increased risk of developing thromboembollic disease. the thrombotic effects of oral contraceptive (oc) are probably mediated, at least partly through their effects on the coagulation system. plasma levels of several clotting factors have been shown to be elevated in oc users, and this increase is graduated accordin...

Factor IX is synthesized in a precursor form with a propeptide that contains the gamma-carboxylation recognition site, an element which directs the post-translational gamma-carboxylation of adjacent glutamic acid residues. After protein synthesis, the propeptide is cleaved to yield the mature Factor IX. To study propeptide processing, anti-proFactor IX antibodies were prepared using a synthetic...

We have determined the 2905 nucleotide sequence of the rhesus macaque factor IX complementary DNA (cDNA) and found it to be greater than 95% identical to that of the human factor IX cDNA. The cDNA has a large 3' untranslated region like the human cDNA, but unlike the human cDNA has two polyadenylation sites 224 nucleotides apart that are used for transcription of the messenger RNA. The deduced ...

This study includes 47 normal subjects and 25 hemophilia B patients without inhibitor(s), showing different factor IX coagulant activity and antigen levels. Genomic DNA, digested with various restriction endonucleases, was hybridized with two different factor IX probes, ie, the cDNA and the subgenomic probe for the intragenic TaqI polymorphic site. cDNA restriction patterns suggest absence of g...

The platelet receptor for von Willebrand factor (VWF), glycoprotein (GP) Ib-IX, mediates initial platelet adhesion and activation. It is known that the cytoplasmic domain of GPIb is phosphorylated at Ser by cAMPdependent protein kinase (PKA). To understand the physiological role of GPIb phosphorylation, a GPIb-IX mutant replacing Ser of GPIb with alanine (S166A) and a deletion mutant lacking re...

The platelet receptor for von Willebrand factor (VWF), glycoprotein (GP) Ib-IX, mediates initial platelet adhesion and activation. It is known that the cytoplasmic domain of GPIbbeta is phosphorylated at Ser(166) by cAMP-dependent protein kinase (PKA). To understand the physiological role of GPIbbeta phosphorylation, a GPIb-IX mutant replacing Ser(166) of GPIbbeta with alanine (S166A) and a del...

The glycoprotein (Gp) Ib/IX complex contains three transmembranous leucine-rich repeat polypeptides (GpIbalpha, GpIbbeta, and GpIX) that form the platelet von Willebrand factor (vWF) receptor. GpIb/IX functions to effect platelet adhesion, activation, and aggregation under conditions of high shear stress. GpIb/IX is expressed late in the ontogeny of megakaryocytes, the precursor cell that relea...

The role of the factor IXa heparin-binding exosite in coagulation was assessed with mutations that enhance (R170A) or reduce (R233A) stability of the protease-factor VIIIa A2 domain interaction. After tissue factor (TF) addition to reconstituted factor IX-deficient plasma, factor IX R170A supported a 2-fold increase in velocity index (slope) and peak thrombin concentration, whereas factor IX R2...

  Background: Factor VII concentrates are used in patients with congenital or acquired factor VII deficiency or treatment of hemophilia patients with inhibitors. In this research, immunoaffinity chromatography was used to purify factor VII from prothrombin complex (Prothrombin-Proconvertin-Stuart Factor-Antihemophilic Factor B or PPSB) which contains coagulation factors II, VII, IX and X. The a...