Factor VIII coagulation

Factor VIII Coagulation proteins hemophilia A treatment 300 3 X 10- ... 

Hemophilia A Determine factor VIII coagulant activity before injecting desmopressin for hemostasis if activity is <5% of normal, do not rely on desmopressin... 

Von Willebrand s disease Assess levels of factor VIII coagulant, factor VIII antigen, and ristocetin cofactor skin bleeding time may also be helpful... 

CHAPTER 36, FIGURE 6 Cofactor proteins, factor V and factor VIII. Factor V and factor VIII coagulant (not the von Willebrand factor carrier of factor VIII) contain six distinct structural domains. The two A domains. A, and Aj at the N-terminal end of the polypeptide chain, are separated from the Aj domain by a highly glycosylated B domain. The two C domains are at the C-terminal end of the molecule. The A domain sequences are homologous to the A domains of ceruloplasmin. Both factor Va and factor Villa act as catalysts in the activation of prothrombin and factor X, respectively. Activation sites are indicated by green arrows inactivation sites by red arrows. In factor Va, complete inactivation requires cleavage of Arg ° . 

Coagulation Factor VIII-SD VIII C Vactor T7/I SD New York Blood Center... 

Coagulation Factor VIII-SD VIIFC SD American Red Cross... 

Antihemophilic factor [9001-28-9] (AHF) is a protein found in normal plasma that is necessary for clot formation. It is needed for transformation of prothrombin to thrombin. Administration of AHF by injection or infusion can temporarily correct the coagulation defect present in patients with hemophilia. Antihemophilic factor VIII (Alpha Therapeutic) has been approved by the FDA as replacement therapy in patients with hemophilia B to prevent bleeding episodes, and also during surgery to correct defective hemostasis (178). 

Genetic disorders of coagulation factors occur, and the two most common involve factors VIII (hemophilia A) and IX (hemophilia B). 

Hemophilia A and B are coagulation disorders that result from defects in the genes encoding for plasma coagulation proteins. Hemophilia A (classic hemophilia) is caused by the deficiency of factor VIII, and hemophilia B (Christmas disease) is caused by the deficiency of factor IX. The incidences of hemophilia A and B are estimated at 1 in 5000 and 1 in 30,000 male births, respectively. Both types of hemophilia are evenly distributed across all ethnic and racial groups.1... 

The pathophysiology of hemophilia is based on the factor VIII or IX deficiency resulting in inadequate thrombin generation and an impaired intrinsic-pathway coagulation cascade (see... 

PCCs contain the vitamin K-dependent factors II, VII, IX, and X. These agents represent another attempt to bypass the factor at which the antibody is directed (see Fig. 64-2). However, PCCs carry the risk of serious thrombotic complications. Porcine factor VIII is most useful when the inhibitor titer is less than 50 BU (see Fig. 64-2 for dose and frequency). Owing to its similarity to human factor VIII, porcine factor VIII participates in the coagulation cascade. However, most inhibitors have very weak neutralizing activity against it. Porcine factor VIII is a third-line agent (only after factor Vila and a PCC have failed) owing to a 15% incidence of cross-reactivity.15... 

Some 5-25 per cent of individuals suffering from haemophilia A develop anti-factor VIII antibodies, and 3-6 per cent of haemophilia B sufferers develop anti-factor IX antibodies. This complicates treatment of these conditions and, as mentioned previously, one approach to their treatment is direct administration of factor Vila. The therapeutic rationale is that factor Vila could directly activate the final common steps of the coagulation cascade, independently of either factor VIII or IX (Figure 12.1). Factor Vila forms a complex with tissue factor that, in the presence of phospholipids and Ca2+, activates factor X. 

Blood-Coagulation Factor VIII Genetics, Physiological Control, and Bioassay G. I. C. Ingram... 

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