The regulation of human Factor IXa was studied in vitro in human and mouse plasma and in vivo in the mouse. In human plasma, approximately 60% of the 125I-Factor IXa was bound to antithrombin III (ATIII) by 2 h, with no binding to alpha 2-macroglobulin or alpha 1-proteinase inhibitor, as assessed by gel electrophoresis and IgG- antiproteinase inhibitor-Sepharose beads. In the presence of hepari...

To determine the functional role of the metal-dependent conformational changes in Factor IX, two populations of conformation-specific anti-Factor IX antibodies were prepared. Anti-Factor IX X Mg(II) antibodies bind to Factor IX in the presence of Mg(II) and other metal ions, but not in the absence of metal ions. Anti-Factor IX X Ca(II)-specific antibodies bind to Factor IX in the presence of Ca...

Because there have been reports that factor IX concentrate is less immunosuppressive and therefore factor IX users have less immunologic aberrations, we have studied a group of 22 patients with hemophilia B and six patients with factor VIII deficiency and high titer inhibitors with respect to lymphocyte numbers and function, human immunodeficiency virus (HIV) serology, and factor usage. This gr...

There is increasing evidence that hypoxia-regulated gene expression influences tumor aggressiveness, contributing to the poorer outcome of patients with hypoxic tumors. The role of the transcriptional complex hypoxia-inducible factor-1 as an important mediator of hypoxia-regulated gene expression is one of the best documented pathways. Recently, it has emerged that certain tumor-associated carb...

We describe a novel point mutation in the fourth exon of human factor IX (encoding the first EGF-like domain) in which cytosine is substituted for adenosine at position 10,401, resulting in the substitution of proline for glutamine at position 50 in the polypeptide chain. Sequence analysis of all eight exons, all exon-intron junctions, 160 base pairs (bp) of DNA 5' to the proposed translation s...