A Method for Assaying von Willebrand Factor (Ristocetin Cofactor)

Macfarlane, Donald E.; Stibbe, J.; Kirby, Edward P.; Zucker, Marjorie B.; Grant, Robert A.; McPherson, Jean

doi:10.1055/s-0038-1651343

Cited by 288 publications

(191 citation statements)

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“…Von Willebrand factor antigen was assayed by an ELISA using rabbit anti-human vWF and rabbit horseradish peroxidase-conjugated anti-human vWF polyclonal antibodies [7]. Ristocetin cofactor activity was assayed with formalin-fixed platelets [11] (intra-assay variation 10%; inter-assay variation 11%). The binding of vWF to collagen was measured according to the ELISA-based method of Brown and Bosak [3], with slight modifications (intraassay variation 5%, inter-assay variation 9%).…”

Section: Methodsmentioning

confidence: 99%

Acquired von Willebrand disease as a cause of recurrent mucocutaneous bleeding in primary thrombocythemia: Relationship with platelet count

et al. 1994

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SummaryWe present a 4-year follow-up of a 42-yearold patient with primary thrombocythemia whose clinical course was complicated by two major mucocutaneous bleeding episodes. On both occasions an acquired functional yon Willebrand factor deficiency was demonstrated. In contrast to what is reported in the literature, an inverse relationship between platelet number and plasma high-molecular-weight multimers of von Willebrand factor was established.

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Section: Methodsmentioning

confidence: 99%

Acquired von Willebrand disease as a cause of recurrent mucocutaneous bleeding in primary thrombocythemia: Relationship with platelet count

et al. 1994

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“…9 A ratio between VWF:RCo activity and VWF antigen (VWF:Ag) below 0.6 is paradigmatic of dysfunctional type 2A and 2M VWD. In type 2A VWD, there is a variable lack of HMWM, caused mainly by mutations in the A2 domain affecting the multimerization process or susceptibility to ADAMTS-13, but also in D1/D2 multimerization regions and the C-terminal CK region.…”

Section: Type 2 Vwd: a Heterogeneous Disease Subgroupmentioning

confidence: 99%

How I treat type 2 variant forms of von Willebrand disease

Tosetto

Castaman²

2015

Blood

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Type 2 von Willebrand disease (VWD) includes a wide range of qualitative abnormalities of von Willebrand factor structure and function resulting in a variable bleeding tendency. According to the current classification, 4 different subtypes can be identified, each with distinctive phenotypic and therapeutic characteristics. Current available laboratory methods allow a straightforward approach to VWD subtyping, and although the precise molecular characterization remains complex, it is not required for appropriate treatment of the vast majority of cases. Desmopressin can be useful only in a few type 2 cases compared with patients with actual quantitative deficiency (type 1), most often in variants with a nearly normal multimeric pattern (type 2M). However, since no laboratory test accurately predicts response to desmopressin, a trial test should always be performed in all type 2 VWD patients, with the exception of type 2B ones. Replacement therapy with plasma-derived von Willebrand factor-factor VIII concentrates represents the safe mainstay of treatment of all patients, particularly those not responding to desmopressin or requiring a sustained hemostatic correction because of major surgery or bleeding. A significant patient bleeding history correlates with increased bleeding risk and should be considered in tailoring the optimal antihemorrhagic prophylaxis in the individual patient.

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“…Coagulation factor VIII was measured using a chromogenic substrate method for photometric determination of prothrombin time as previously described (27). vWF was measured as described previously (28,29). Serum TM was determined by a one-step sandwich enzyme immunoassay, the reported sensitivity of which is 1 mg/l for soluble TM (30,31).…”

Section: Serum Parametersmentioning

confidence: 99%

Change in von Willebrand factor and carotid intima-media thickness in hypothyroid patients with normal thyroid function after levothyroxine replacement therapy

Nagasaki

Inaba

Henmi

et al. 2004

European Journal of Endocrinology

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Objective: This study examined whether levothyroxine (L-T 4 ) replacement might affect serum markers of endothelium injury, including von Willebrand factor (vWF), factor VIII activity and thrombomodulin (TM), during normalization of increased intima-media thickness (IMT) in the common carotid artery (CCA) in hypothyroid patients after L-T 4 replacement therapy. Patients and methods: Thirty-three hypothyroid patients were examined for vWF, factor VIII, TM and CCA IMT before and after 1 year of normalization of thyroid function by L-T 4 replacement. CCA IMT was measured from digitized still images taken during scanning by high-resolution ultrasonography as an indicator of early atherosclerosis. Results: Serum factor VIII and vWF increased significantly during 1 year of normalization of thyroid function (from 122.7^9.4 to 151.3^18.8% (P , 0.05) and from 109.9^9.6 to 135.2^12.4% (P , 0.005) respectively), although these values all fell within the respective normal range. Serum TM, in contrast, did not change appreciably in response to L-T 4 treatment, moving from 2.57^0.15 to 2.74^0.18 ng/ml (P ¼ 0.086). During 1 year of a euthyroid state, all patients showed a significant decrease in CCA IMT (P , 0.0001). Change in serum vWF, but not in factor VIII or TM, showed a positive correlation with that of CCA IMT during L-T 4 replacement therapy. Furthermore, the change in serum vWF was significantly and independently associated with change in CCA IMT (r ¼ 0.490, P ¼ 0.0038).Conclusions: The present study demonstrated that the improvement of CCA IMT during L-T 4 treatment might have the potential to attenuate an elevation of vWF and to attenuate vascular injury by the cardiovascular effects of thyroid hormone in hypothyroid patients. 150 125-131 European Journal of Endocrinology

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A Method for Assaying von Willebrand Factor (Ristocetin Cofactor)

Cited by 288 publications

References 0 publications

Acquired von Willebrand disease as a cause of recurrent mucocutaneous bleeding in primary thrombocythemia: Relationship with platelet count

Acquired von Willebrand disease as a cause of recurrent mucocutaneous bleeding in primary thrombocythemia: Relationship with platelet count

How I treat type 2 variant forms of von Willebrand disease

Change in von Willebrand factor and carotid intima-media thickness in hypothyroid patients with normal thyroid function after levothyroxine replacement therapy

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