Measurement of factor VIII activity of B-domain deleted recombinant factor VIII

2001 ◽  
Vol 38 (2, Suppl 4) ◽  
pp. 13-23 ◽  
Author(s):  
M. Mikaelsson ◽  
U. Oswaldsson ◽  
M. A. Jankowski
Keyword(s):  
Factor Viii ◽  
Recombinant Factor Viii ◽  
Factor Viii Activity

Quantitative Evaluation of Factor VIII in Factor VIII Products.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4012-4012
Author(s):  
Saulius Butenas ◽  
Behnaz Parhami-Seren ◽  
Matthew T. Gissel ◽  
Edward D. Gomperts ◽  
Kenneth G. Mann
Keyword(s):  
Factor Viii ◽  
Protein Content ◽  
Quantitative Evaluation ◽  
Hemophilia A ◽  
Specific Activity ◽  
Full Length ◽  
Recombinant Factor Viii ◽  
Factor Viii Activity

Abstract Several factor VIII products, recombinant and natural, have been used for hemophilia A treatment worldwide. Typically, two activity-based assays (factor Xase and aPTT) are used for the assessment of factor VIII concentration in these products. Frequently, the results are dependent upon the assay and its modifications in different laboratories. In this study, we evaluated five pharmacologic factor VIII products (three lots of each) in three activity-based assays and in two immunoassays for the concentration and activity of factor VIII protein. Two factor VIII products were plasma-derived (Immunate and Hemofil M) and three were recombinant; two of these contained full-length factor VIII (Recombinate and Kogenate) and one was B-domainless (ReFacto). Albumin-free full-length recombinant factor VIII was used as a standard in all assays. In the factor Xase assay, all recombinant factor VIII products and Immunate at 1U/ml (indicated by manufacturer) showed activity similar to that of 0.7nM (1U/ml) standard, whereas activity of Hemofil M was 64–68% of the standard. In the aPTT assay both full-length recombinant products and Hemofil M displayed activity similar to the standard, whereas Immunate had increased (142% of standard) and ReFacto decreased (83% of standard) activity. In synthetic plasma, all three recombinant products had standard-like activity, whereas Hemofil M and Immunate were slightly more active than standard. The ELISA immunoassay revealed that the factor VIII protein content in Recombinate, Kogenate and Hemofil M corresponded to the units assigned by manufacturers (1.4–1.6x1012U/mol vs1.4x1012U/mol calculated for standard), whereas the specific activity of Immunate was 50% of that expected (0.7x1012U/mol). In contrast, the specific activity of ReFacto was almost 3-fold that of full-length factor VIII (4.0x1012U/mol). The data of this study indicate that: 1) factor VIII activity estimated in different assays gives dissimilar results; 2) the specific activity of factor VIII in various factor VIII products is different and, as a consequence, administration of an equal factor VIII activity in U/ml means the administration of different amounts of factor VIII protein.

Effects of chemical modifiers on recombinant factor VIII activity

1995 ◽  
Vol 80 (3) ◽  
pp. 247-254 ◽  
Author(s):  
Fiona Manning ◽  
Ciarán Ó Fágáin ◽  
Richard O'Kennedy ◽  
Barry Woodhams
Keyword(s):  
Factor Viii ◽  
Recombinant Factor Viii ◽  
Factor Viii Activity ◽  
Chemical Modifiers

Thrombelastography during and after Elective Abdominal Surgery

1978 ◽  
Vol 39 (02) ◽  
pp. 488-495 ◽  
Author(s):  
J M Butler
Keyword(s):  
Abdominal Surgery ◽  
Factor Viii ◽  
Whole Blood ◽  
Dominant Factor ◽  
Fibrinogen Concentration ◽  
Factor Viii Activity ◽  
Elective Abdominal Surgery

SummaryThrombelastography has been performed on recalcified whole blood from 50 patients before, during and after elective abdominal surgery. The characteristic changes of the thrombelastographic indices r, k and mA are described.During operation r and k shortened, but no change in mA was observed. This response was in part associated with an increase in factor VIII activity. Following operation, while r time was somewhat shortened, much more marked changes in k and mA were evident. Increasing fibrinogen concentration was the dominant factor in determining the post-operative changes in the thrombelastograph.

Heparin, Protamine and Polybrene

1965 ◽  
Vol 13 (02) ◽  
pp. 550-560 ◽  
Author(s):  
Anthony Britten
Keyword(s):  
Factor Viii ◽  
Incubation Mixture ◽  
Factor V ◽  
Factor Viii Activity ◽  
Rapid Loss

SummaryThe effects of incubating heparin, protamine or Polybrene with plasma were studied. All three drugs cause rapid loss of factor V from decalcified plasma, while Polybrene also accelerates the loss of factor VIII activity. These changes are related to temperature, the period of incubation and the dose of the drug used, and can be partially prevented by inclusion of neutralizing doses of the appropriate antagonist in the incubation mixture.The implications of these findings are discussed.

A Multicenter Pharmacosurveillance Study for the Evaluation of the Efficacy and Safety of Recombinant Factor VIII in the Treatment of Patients with Hemophilia A

1997 ◽  
Vol 78 (05) ◽  
pp. 1352-1356 ◽  
Author(s):  
Emel Aygören-Pürsün ◽  
Inge Scharrer ◽  
Keyword(s):  
Factor Viii ◽  
Hemophilia A ◽  
Parvovirus B19 ◽  
Subjective Evaluation ◽  
Recombinant Factor Viii ◽  
Fviii Inhibitor ◽  
Previously Treated Patients ◽  
Previously Treated ◽  
Bleeding Episodes ◽  
Recombinant Fviii

SummaryIn this open multicenter study the safety and efficacy of recombinant factor VIII (rFVIII) was assessed in 39 previously treated patients with hemophilia A (factor VIII basal activity ≤15%).Recombinant FVIII was administered for prophylaxis and treatment of bleeding episodes and for surgical procedures. A total of 3679 infusions of rFVIII were given. Efficacy of rFVIII as assessed by subjective evaluation of response to infusion and mean annual consumption of rFVIII was comparable to that of plasma derived FVIII concentrates. The incremental recovery of FVIII (2.4 ± 0,83%/IU/kg, 2.12 ± 0.61%/IU/kg, resp.) was within the expected range. No clinical significant FVIII inhibitor was detected in this trial. Five of 16 susceptible patients showed a seroconversion for parvovirus B19. However, the results are ambiguous in two cases and might be explained otherwise in one further case. Thus, in two patients a reliable seroconversion for parvovirus B19 was observed.

Anti-apoptotic genes Aven and E1B-19K enhance performance of BHK cells engineered to express recombinant factor VIII in batch and low perfusion cell culture

2007 ◽  
Vol 98 (4) ◽  
pp. 825-841 ◽  
Author(s):  
Toey Nivitchanyong ◽  
Amanda Martinez ◽  
Adiba Ishaque ◽  
John E. Murphy ◽  
Konstantin Konstantinov ◽  
...  
Keyword(s):  
Cell Culture ◽  
Factor Viii ◽  
Recombinant Factor Viii ◽  
Perfusion Cell Culture ◽  
Bhk Cells ◽  
Apoptotic Genes

scholarly journals Long‐term safety and efficacy of recombinant factor VIII Fc fusion protein (rFVIIIFc) in subjects with haemophilia A

Haemophilia ◽  
2015 ◽  
Vol 22 (1) ◽  
pp. 72-80 ◽  
Author(s):  
B. Nolan ◽  
J. Mahlangu ◽  
D. Perry ◽  
G. Young ◽  
R. Liesner ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Factor Viii ◽  
Recombinant Factor Viii ◽  
Haemophilia A ◽  
Safety And Efficacy ◽  
Fc Fusion Protein

Factor VIII Activity in Haemophilic Plasma unmasked by Synthetic Organic Anions

1972 ◽  
Vol 240 (100) ◽  
pp. 144-145 ◽  
Author(s):  
EDITH VON KAULLA ◽  
KURT N. VON KAULLA
Keyword(s):  
Factor Viii ◽  
Organic Anions ◽  
Factor Viii Activity
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