Crystal Fulcher

Learn More
We have identified a Factor VIII (FVIII) binding domain residing within the amino-terminal 272 amino acid residues of the mature von Willebrand Factor (vWF) subunit. Two-dimensional crossed immunoelectrophoresis showed direct binding of purified human FVIII to purified human vWF. After proteolytic digestion of vWF with Staphylococcus aureus V8 protease(More)
The effective activation of factor X by factor IXa requires the co-factor activity of activated factor VIII (FVIII). Factor Xa formation is also dependent on the presence of negatively charged phospholipid. A phospholipid binding domain of FVIII has been reported to be present on the FVIII light chain. Recent observations on a subset of human FVIII(More)
We have analyzed the factor VIII (FVIII) protein and the nucleotide sequence around two thrombin cleavage sites, at arginine 372 in the FVIII heavy chain and arginine 1689 in the FVIII light chain in a naturally occurring dysfunctional FVIII variant, FVIII Okayama. The patient was a 42-year-old hemophiliac with a FVIII coagulant activity of 0.03 U/mL and a(More)
Purified human factor VIII procoagulant protein (VIII:C) was treated with purified human activated protein C (APC) and the loss of VIII:C activity correlated with proteolysis of the VIII:C polypeptides. APC proteolyzed all VIII:C polypeptides with mol wt = 92,000 or greater, but not the doublet at mol wt = 79-80,000. These results and our previous thrombin(More)
We used immunoblotting of purified factor VIII coagulant protein (FVIII) to localize FVIII inhibitor epitopes in 76 inhibitor plasmas to either the 92-kd FVIII polypeptide (and its 54-kd and/or 44-kd thrombin fragments), the 80-kd polypeptide (and its 72-kd thrombin fragment), or both of these polypeptides. We also used immunoblotting to examine the(More)
Epitopes for 22 alloantibodies that inhibit factor VIII procoagulant protein (FVIII) from multitransfused individuals with severe hemophilia A and three autoantibodies from nonhemophilic individuals appeared to be restricted to two specific regions of the FVIII molecule. Immunoblotting of purified FVIII and purified thrombin-degraded FVIII, followed by(More)
Human factor VIII(FVIII) inhibitors are pathologic, circulating antibodies that inactivate FVIII. We have examined the location of epitopes on the FVIII protein for inhibitors from hemophilia A and nonhemophilic individuals. The inhibitors were of type I or type II in the kinetics of their inactivation of FVIII. A cDNA clone of human FVIII was used to(More)
Epitopes for antibodies that inhibit factor VIII procoagulant protein were analyzed by deletion mapping of factor VIII protein fragments expressed in Escherichia coli. A human factor VIII cDNA clone was used to generate E. coli expression vectors encoding fragments containing the 80-kDa factor VIII light chain (A3, C1, and C2 domains) and the 44-kDa(More)
We have used immunoblotting of purified factor VIII (FVIII) to determine whether or not changes in FVIII chain specificity occur during the course of an inhibitor. Serial plasma samples from 15 inhibitor patients (13 hemophilic and two spontaneous) were analyzed. Nine of the 15 antibodies, all with epitopes on the 44-kilodalton (Kd) thrombin fragment of the(More)
Factor VIII procoagulant protein (VIII:C) purified from commercial factor VIII concentrate contained multiple polypeptides ranging in mol wt from 79,000 to 188,000, all of which were removed from solution by a monoclonal anti-VIII:C antibody specific for a thrombin-sensitive epitope. In a time-course digest of the purified VIII:C using a trace amount of(More)