A two-centre comparative evaluation of new automated assays for von Willebrand factor ristocetin cofactor activity and antigen

Haemophilia ◽  
2013 ◽  
Vol 20 (1) ◽  
pp. 147-153 ◽  
Author(s):  
F. Stufano ◽  
A. S. Lawrie ◽  
S. La Marca ◽  
C. Berbenni ◽  
L. Baronciani ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Comparative Evaluation ◽  
Cofactor Activity ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor ◽  
Ristocetin Cofactor Activity

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

1997 ◽  
Vol 78 (02) ◽  
pp. 930-933 ◽  
Author(s):  
Ping Chang ◽  
D L Aronson
Keyword(s):  
Von Willebrand Factor ◽  
Functional Activity ◽  
Binding Activity ◽  
Collagen Binding ◽  
Binding Function ◽  
Cofactor Activity ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor ◽  
Ristocetin Cofactor Activity

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.

scholarly journals Selective absence of large forms of factor VIII/von Willebrand factor in acquired von Willebrand's syndrome. Response to transfusion

Blood ◽  
1979 ◽  
Vol 54 (3) ◽  
pp. 600-606 ◽  
Author(s):  
D Meyer ◽  
D Frommel ◽  
MJ Larrieu ◽  
TS Zimmerman
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Procoagulant Activity ◽  
Factor Viii Related Antigen ◽  
Cofactor Activity ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor ◽  
Ristocetin Cofactor Activity

Abstract A previously healthy elderly man with mucocutaneous bleeding was found to have a benign monoclonal IgG gammapathy associated with criteria for severe von Willebrand disease (Factor VIII procoagulant activity, Factor-VIII-related antigen, and ristocetin cofactor activity, less than 10% of normal). Associated qualitative abnormalities of factor VIII/von Willebrand factor were demonstrated by radiocrossed immunoelectrophoresis and immunoradiometric assay. The late clinical onset and negative family history are in favor of an acquired form of vWD. The monoclonal gammapathy and abnormalities of factor VIII/von Willebrand factor have been stable over a 10-yr period. No inhibitor to Factor VIII procoagulant activity, ristocetin cofactor activity, or Factor-VIII-related antigen could be demonstrated. Following transfusion of cryoprecipitate (with a normal cross immunoelectrophoretic pattern), there was a rapid removal of the large forms of Factor.-VIII-related antigen, paralleled by a decay of ristocetin cofactor activity. The transfusion study of this patient with acquired von Willebrand disease type II (variant of von Willebrand disease) serves to emphasize the relationship between polydispersity of Factor VIII/von Willebrand Factor and functional heterogeneity.

von Willebrand Factor Ristocetin Cofactor Activity Correlates with Platelet Function in a High Shear Stress System

2000 ◽  
Vol 84 (10) ◽  
pp. 727-728 ◽  
Author(s):  
Agnès Veyradier ◽  
Edith Fressinaud ◽  
Catherine Boyer-Neumann ◽  
Marc Trossaert ◽  
Dominique Meyer
Keyword(s):  
Shear Stress ◽  
Von Willebrand Factor ◽  
Stress System ◽  
High Shear ◽  
High Shear Stress ◽  
Cofactor Activity ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor ◽  
Ristocetin Cofactor Activity

Reduced von Willebrand factor survival in type Vicenza von Willebrand disease

Blood ◽  
2002 ◽  
Vol 99 (1) ◽  
pp. 180-184 ◽  
Author(s):  
Alessandra Casonato ◽  
Elena Pontara ◽  
Francesca Sartorello ◽  
Maria Grazia Cattini ◽  
Maria Teresa Sartori ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Bleeding Tendency ◽  
Normal Platelet ◽  
Cofactor Activity ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor ◽  
Ristocetin Cofactor Activity ◽  
Original Type

Type Vicenza variant of von Willebrand disease (VWD) is characterized by a low plasma von Willebrand factor (VWF) level and supranormal VWF multimers. Two candidate mutations, G2470A and G3864A at exons 17 and 27, respectively, of the VWF gene were recently reported to be present in this disorder. Four additional families, originating from northeast Italy, with both mutations of type Vicenza VWD are now described. Like the original type Vicenza subjects, they showed a mild bleeding tendency and a significant decrease in plasma VWF antigen level and ristocetin cofactor activity but normal platelet VWF content. Unlike the original patients, ristocetin-induced platelet aggregation was found to be normal. Larger than normal VWF multimers were also demonstrated in the plasma. Desmopressin (DDAVP) administration increased factor VIII (FVIII) and VWF plasma levels, with the appearance of even larger multimers. However, these forms, and all VWF oligomers, disappeared rapidly from the circulation. The half-life of VWF antigen release and of elimination was significantly shorter than that in healthy counterparts, so that at 4 hours after DDAVP administration, VWF antigen levels were close to baseline. Similar behavior was demonstrated by VWF ristocetin cofactor activity and FVIII. According to these findings, it is presumed that the low plasma VWF levels of type Vicenza VWD are mainly attributed to reduced survival of the VWF molecule, which, on the other hand, is normally synthesized. In addition, because normal VWF-platelet GPIb interaction was observed before or after DDAVP administration, it is proposed that type Vicenza VWD not be considered a 2M subtype.

scholarly journals A new variant of type II von Willebrand disease with aberrant multimeric structure of plasma but not platelet von Willebrand factor (type IIF)

Blood ◽  
1986 ◽  
Vol 68 (1) ◽  
pp. 269-274 ◽  
Author(s):  
PM Mannucci ◽  
R Lombardi ◽  
AB Federici ◽  
JA Dent ◽  
TS Zimmerman ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Normal Plasma ◽  
Von Willebrand Factor Antigen ◽  
Cofactor Activity ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen ◽  
Ristocetin Cofactor ◽  
Ristocetin Cofactor Activity

Abstract A patient with a lifelong bleeding disorder was diagnosed as having Type II von Willebrand disease. The larger multimers of von Willebrand factor were absent from her plasma but present in platelets. A high- resolution electrophoretic technique was used to study the complex structure of individual von Willebrand factor multimers. In normal plasma, each multimer could be resolved into five bands: a more intense central one and four less intense, two moving faster and two slower than the central band. In normal platelets, each multimer could also be resolved into five bands. The central one had a mobility similar to that in plasma, whereas the four satellite bands had a mobility that differed from that of the corresponding plasma bands. In the patient, platelet von Willebrand factor antigen content and ristocetin cofactor activity were normal, and von Willebrand factor showed the same structure of individual multimers as seen in normal platelets. On the other hand, plasma von Willebrand factor antigen and ristocetin cofactor activity were decreased, and the structure of individual von Willebrand factor multimers was different from that of normal plasma and similar to that seen in normal and patient's platelets. After infusion of 1-deamino-8-D-arginine vasopressin, the largest von Willebrand factor multimers, as well as new satellite bands with a mobility similar to those in normal plasma, appeared in the patient plasma, and the levels of von Willebrand factor antigen and ristocetin cofactor activity became normal. Yet no relevant change in the prolonged bleeding time was observed. This new variant of von Willebrand disease, therefore, is characterized by the presence of a dysfunctional von Willebrand factor molecule that exhibits unique structural abnormalities in plasma but appears to be normal in platelets. The designation of Type IIF is proposed for this type of von Willebrand disease in accordance with the terminology that has been previously used.

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