Variable Degradation of Factor VIII‐Related Protein in Lyophilised Concentrates of Antihaemophilic Factor (AHF)<sup>1</sup>

Jakab, T; Pflugshaupt, R.; Furlan, Miha; Beck, Eugene A.

doi:10.1111/j.1423-0410.1978.tb02898.x

Cited by 13 publications

(2 citation statements)

References 10 publications

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“…Other studies of the early, i.e. pre 1980's, factor VIII preparations indicate they inhibited platelet function both in vivo and in vitro (27)(28). A reasonable hypothesis is that the degraded proteins, possibly RGD containing peptides,were competitive inhibitors of vWF activity both in vivo and in vitro.…”

Section: Antigenmentioning

confidence: 94%

Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities

Chang

Aronson

1997

Thromb Haemost

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SummaryFive plasma preparations (11 lots) used in the treatment of von Willebrand’s disease (vWD) were evaluated. The collagen binding function of von Willebrand factor (vWF) containing preparations was compared with the ristocetin cofactor activity and the vWF antigen. Some preparations have higher ratio of functional activity (ristocetin cofactor and collagen binding) relative to the antigen than is found in normal plasma. The ristocetin cofactor activity and the collagen binding activity are tightly correlated (r = .95). Ultracentrifugal (UCF) analysis was used to compare the size distribution of vWf antigen, ristocetin cofactor and collagen binding activity. The sedimentation of all of the vWF parameters in the plasma products was slower than in plasma. In plasma products the ristocetin cofactor activity sediments the most rapidly, the collagen binding activity is slower and the antigen the slowest. The collagen/antigen ratio decreases with decreasing vWF size. Assignment of potency to vWF containing preparations utilizing the collagen binding activity may be more precise and as accurate as with the traditional ristocetin cofactor assay.

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Section: Antigenmentioning

confidence: 94%

Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities

Chang

Aronson

1997

Thromb Haemost

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“…Their results indicated that the VI1IR:RCF levels in concentrates were overestimated by the aggregometer method. Several workers have now shown that determination of VI1IR:RCF fails to reflect the bleeding time corrective properties of the Factor Vlll/von Willebrand factor in Factor Vlll concentrates (Blatt et al, 1976;Green and Potter, 1976;Mannucci et at., 1976;Nilsson and Hedner, 1977;Weinstein and Deykin, 1979). Thus, despite a high concentration of VIIIR:RCF, the high purity concentrates have no effect on the bleeding time or the bleeding tendency.…”

Section: Wavpoc I Kobimentioning

confidence: 99%

Factor Viii Related Activities in Concentrates

Nilsson¹,

Borge²,

Gunnarsson³

et al. 1984

Scandinavian Journal of Haematology

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Factor VIII related activities were investigated in 3 low purity concentrates (fraction 1‐0 and freeze‐dried cryoprecipitates), 2 intermediate concentrates, and 8 high purity concentrates. The parameters studied were VIII:C by one‐stage assay and chromogenic assay, VIII clotting antigen (VIII:CAg), VIII related antigen (VIIIR:Ag) by electroimmunoassay, immunoradiometric assay (IRMA), crossed immuno‐electrophoresis (CIE) and SDS agarose gel electrophoresis followed by staining with radioactive antibody, ristocetin cofactor activity (R:RCF) and fibrinogen. The VIII:C values from the chromogenic assay method agreed well with those obtained by the one‐stage assay. The specific activity varied considerably between the different concentrates and even between different batches. DDAVP Octonativ and Factorate had the highest specific activity. With the exception of Factorate, all preparations had higher concentrations of VIII:CAg than of VIII:C — probably indicating inactivation of the biological activity of VIII:C during the manufacturing process. Studies of the Factor VIII/von Willebrand factor showed that all the concentrates contain considerable amounts of VIIIR:Ag as measured by electroimmunoassay. The intermediate and the high purity concentrates had much lower concentration of VIIIR:Ag as determined by IRMA than by electroimmunoassay, and the dose response curves were non‐parallel. On CIE they showed an abnormal migration. Multimeric sizing demonstrated that all the intermediate and high purity concentrates were lacking in the high molecular weight multimers. Fraction 1‐0 and the cryoprecipitates, the only preparations capable of correcting the bleeding defect in patients with von Willebrand's disease, showed about the same concentration of VIIIR:Ag as determined by electroimmunoassay and IRMA, normal migration in CIE, and the same multimeric pattern as normal plasma. The VIIIR:RCF values were much lower than those for VIIIR:Ag, as determined by electroimmunoassay. Thus, considerable differences were found of the in vitro properties of Factor VIII related activities between low, intermediate and high purity Factor VIII concentrates. The action of proteases and the techniques used in purification probably have a crucial effect on the properties.

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Von willebrand factor (VIII_VWF) in lyophilized factor VIII concentrates

McCue¹,

Brossoit

Marmer

et al. 1980

American J Hematol

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Several (14) commercially prepared, lyophilized Factor VIII concentrates were assayed for VIIIAHF, VIIIAg, and VIIIVWF. Significant levels of VIIIAg (immunologic) and VIIIVWF (von Willebrand Factor) were present in addition to VIIIAHF (Functional VIII, Antihemophilic Factor, Factor VIII coagulant activity). An average of 0.95 units of VIIIVWF (range 0.47--1.7) were present for every 1.0 unit of VIIIAHF (as stated on the manufacturer's label). We suggest that the various lyophilized preparations of Factor VIII concentrate available could be assayed for VIIIVWF and should be tested therapeutically in patients with von Willebrand disease.

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Variable Degradation of Factor VIII‐Related Protein in Lyophilised Concentrates of Antihaemophilic Factor (AHF)¹

Cited by 13 publications

References 10 publications

Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities

Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities

Factor Viii Related Activities in Concentrates

Von willebrand factor (VIII_VWF) in lyophilized factor VIII concentrates

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Variable Degradation of Factor VIII‐Related Protein in Lyophilised Concentrates of Antihaemophilic Factor (AHF)1

Cited by 13 publications

References 10 publications

Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities

Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities

Factor Viii Related Activities in Concentrates

Von willebrand factor (VIIIVWF) in lyophilized factor VIII concentrates

Contact Info

Product

Resources

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Variable Degradation of Factor VIII‐Related Protein in Lyophilised Concentrates of Antihaemophilic Factor (AHF)¹

Von willebrand factor (VIII_VWF) in lyophilized factor VIII concentrates