Standardisation of von Willebrand Factor in Therapeutic Concentrates: Calibration of the 1st International Standard for von Willebrand Factor Concentrate (00/514)

2002 ◽  
Vol 88 (09) ◽  
pp. 380-386 ◽  
Author(s):  
Dawn Sands ◽  
Andrew Chang ◽  
Claudine Mazurier ◽  
Anthony Hubbard
Keyword(s):  
Von Willebrand Factor ◽  
International Study ◽  
Expert Committee ◽  
International Standard ◽  
A Value ◽  
Significant Difference ◽  
Factor Concentrate ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Good Agreement

SummaryAn international study involving 26 laboratories assayed two candidate von Willebrand Factor (VWF) concentrates (B and C) for VWF:Antigen (VWF:Ag), VWF:Ristocetin Cofactor (VWF:RCo) and VWF:Collagen binding (VWF:CB) relative to the 4th International Standard Factor VIII/VWF Plasma (4th IS Plasma) (97/586). Estimates of VWF:Ag showed good agreement between different methods, for both candidates, and the overall combined means were 11.01 IU/ml with inter-laboratory variability (GCV) of 10.9% for candidate B and 14.01 IU/ml (GCV 11.8%) for candidate C. Estimates of VWF:RCo showed no significant difference between methods for both candidates and gave overall means of 9.38 IU/ml (GCV 23.7%) for candidate B and 10.19 IU/ml (GCV 24.4%) for candidate C. Prior to the calibration of the candidates for VWF:CB it was necessary to calibrate the 4th IS Plasma relative to local frozen normal plasma pools; there was good agreement between different collagen reagents and an overall mean of 0.83 IU per ampoule (GCV 11.8%) was assigned. In contrast, estimates of VWF:CB in both candidates showed large differences between collagen reagents with inter-laboratory GCV’s of 40%. Candidate B (00/514) was established as the 1st International Standard von Willebrand Factor Concentrate by the WHO Expert Committee on Biological Standardisation in November 2001 with assigned values for VWF:Ag (11.0 IU/ampoule) and VWF:RCo (9.4 IU/ampoule). Large inter-laboratory variability of estimates precluded the assignment of a value for VWF:CB.

Standardisation of Factor VIII – V. Calibration of the 2nd International Standard for Factor VIII and von Willebrand Factor Activities in Plasma

1992 ◽  
Vol 68 (02) ◽  
pp. 155-159 ◽  
Author(s):  
A B Heath ◽  
T W Barrowcliffe
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Expert Committee ◽  
International Standard ◽  
Significant Difference ◽  
Factor Viii Antigen ◽  
Assay Methods ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

SummaryThe proposed 2nd International Standard for Factor VIII and von Willebrand Factor activities in plasma, NIBSC code 87/718, was assayed against the 1st IRP, 80/511, and against fresh normal plasma, in 21 laboratories. There were no significant differences between the various assay methods for factor VIII antigen, von Willebrand factor antigen, and von Willebrand factor ristocetin co-factor activity. For factor VIII clotting activity there was a significant difference between the results of one-stage and two-stage assays. Plasma 87/718 has now been established by the WHO Expert Committee on Biological Standardisation as the 2nd IS for factor VIII and vWF in plasma with the following potencies: VIII:C 0.60 IU/ampoule; VIII:Ag 0.91 IU/ampoule; vWF:Ag 0.91 IU/ampoule; vWF/RCo 0.84 IU/ampoule.

Value assignment of the WHO 2nd International Standard von Willebrand factor, concentrate (09/182)

2011 ◽  
Vol 9 (8) ◽  
pp. 1638-1640 ◽  
Author(s):  
A. R. HUBBARD ◽  
M. HAMILL ◽  
M. BEEHARRY ◽  
S. A. BEVAN ◽  
A. B. HEATH ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Value Assignment ◽  
International Standard ◽  
Factor Concentrate ◽  
Von Willebrand ◽  
Willebrand Factor

scholarly journals Successful management of multiple pregnancies in a family with varying severity of Von Willebrand disease

2018 ◽  
Vol 11 (4) ◽  
pp. 192-194
Author(s):  
Patrick Harrington ◽  
Pippa Kyle ◽  
Jacky Cutler ◽  
Bella Madan
Keyword(s):  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
The Other ◽  
Severe Phenotype ◽  
Mild Phenotype ◽  
History Of ◽  
Specialist Treatment ◽  
Factor Concentrate ◽  
Von Willebrand ◽  
Willebrand Factor

We present the obstetric history of a family of three sisters with Von Willebrand disease, managed in our centre over the course of nine successful pregnancies. The abnormalities result from inheritance of an exon 50 skipping mutation in the Von Willebrand factor gene, resulting from consanguinity. Two of the sisters were identified as having a severe phenotype with a Von Willebrand factor level of less than 5 IU/dl, with the other having a mild phenotype. Of the sisters with a severe phenotype, one had a number of prenatal complications and required early onset prophylaxis with Von Willebrand factor concentrate, whilst the other had a less complicated clinical course, only requiring Von Willebrand factor concentrate to cover labour. The sister with mild Von Willebrand disease had a rise in Von Willebrand factor levels during pregnancy and required no specialist treatment. The report highlights the markedly different clinical courses that can occur in patients with Von Willebrand disease and the different approaches to management.

Spontaneous pyohaemothorax in a teenager with von Willebrand disease: a case report and review of literature

2021 ◽  
Vol 14 (8) ◽  
pp. e241613
Author(s):  
Vaishnavi Divya Nagarajan ◽  
Asha Shenoi ◽  
Lucy Burgess ◽  
Vlad C Radulescu
Keyword(s):  
Case Report ◽  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Surgical Drainage ◽  
Review Of Literature ◽  
History Of ◽  
Factor Concentrate ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

An 18-year-old man with a history of type 3 von Willebrand disease (VWD) presented with a spontaneous pyohaemothorax. Type 3 VWD may present with both mucocutaneous and deep-seated bleeds, such as visceral haemorrhages, intracranial bleeds and haemarthrosis. There have been very few cases described in children of spontaneous pyohaemothorax. Management of this patient was challenging due to risks of bleeding following surgical drainage, requiring constant replacement with von Willebrand factor concentrate, while monitoring factor VIII levels to balance the risks of thrombosis.

scholarly journals Increased plasma von Willebrand factor antigen levels but normal von Willebrand factor cleaving protease (ADAMTS13) activity in preeclampsia

2009 ◽  
Vol 101 (02) ◽  
pp. 305-311 ◽  
Author(s):  
János Rigó Jr ◽  
Tamás Bõze ◽  
Zoltán Derzsy ◽  
László Cervenak ◽  
Veronika Makó ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Von Willebrand Factor ◽  
Hellp Syndrome ◽  
Enzyme Linked Immunosorbent Assay ◽  
Adamts13 Activity ◽  
Elevated Liver Enzymes ◽  
Significant Difference ◽  
Low Platelet Count ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryThe activity of ADAMTS13, the von Willebrand factor (VWF) cleaving protease is low in several conditions, including HELLP (haemolysis, elevated liver enzymes, and low platelet count) syndrome. As HELLP syndrome develops in most cases on the basis of preeclampsia, our aim was to determine whether plasma ADAMTS13 activity is decreased in preeclampsia. Sixty-seven preeclamptic patients, 70 healthy pregnant women and 59 healthy non-pregnant women were involved in this case-control study. Plasma ADAMTS13 activity was determined with the FRETS-VWF73 assay, while VWF antigen (VWF:Ag) levels with an enzyme-linked immunosorbent assay. The multimeric pattern of VWF was analyzed by SDS-agarose gel electrophoresis. There was no significant difference in plasma ADAMTS13 activity between the preeclamptic and the healthy pregnant and non-pregnant groups (median [25–75 percentile]: 98.8 [76.5–112.8] %, 96.3 [85.6–116.2] % and 91.6 [78.5–104.4] %, respectively; p>0.05). However, plasma VWF:Ag levels were significantly higher in preeclamptic patients than in healthy pregnant and non-pregnant women (187.1 [145.6–243.1] % versus 129.3 [105.1–182.8] % and 70.0 [60.2–87.3] %, respectively; p<0.001). The multimeric pattern of VWF was normal in each group. Primiparas had lower plasma ADAMTS13 activity than multi-paras (92.6 [75.8–110.6] % versus 104.2 [92.1–120.8] %; p=0.011). No other relationship was found between clinical characteristics, laboratory parameters and plasma ADAMTS13 activity in either study group. In conclusion, plasma ADAMTS13 activity is normal in preeclampsia despite the increased VWF:Ag levels. However, further studies are needed to determine whether a decrease in plasma ADAMTS13 activity could predis-pose preeclamptic patients to develop HELLP syndrome.

BLEEDING TIME IN NORMAL SUBJECTS: ITS RELATIONSHIP WITH SEX, AGE, BLOOD GROUP, HEMATOCRIT, PLATELET COUNT AND PLASMA VON WILLEBRAND FACTOR LEVEL

1987 ◽  
Author(s):  
F Rodeghiero ◽  
G Castaman ◽  
E Di Bona ◽  
M Ruggeri
Keyword(s):  
Platelet Count ◽  
Blood Group ◽  
Von Willebrand Factor ◽  
Bleeding Time ◽  
Physiological Parameters ◽  
Factor Level ◽  
Significant Difference ◽  
Von Willebrand ◽  
Willebrand Factor

Bleeding time (BT) is the most important test for in "vivo" Vevaluation of primary hemostasis. Several physiological parameters namely sex, age, blood group, hematocrit, platelet count and von Willebrand factor level could exert a significant influenceIn this study, the relationships between BT (Simplate II,General Diagnostics)and these physiological parameters havebeen examined in 58 subjects aging 17-71 (32 males and 26 females; 26 of 0 and 32 of non-0 group). In all the subjects bleedingdiathesis was excluded by interview. They were not taking anvmedicament for at least 10 days and showed normal platelet aggregation by ADP and ArachidonateMean BT value (seconds) was 318± 65 (range 195-A95)Statistical analysis failed to show any significant difference realated to sex and blood group. There was no significant relationship with hematocrit (0.01), platelet count (−0.2A), age (−0.28) and von Willebrand factor level, mesured as ristocetin cofactor (−0.2A). In particular, our data indicate that higher von Willebrand factor levels found in non-0 group in comparison with O-group (113.3 vs 83.5, P < 0:001) do not exert any apparent influence on bleeding time

scholarly journals Influence of mutations and size of multimers in type II von Willebrand disease upon the function of von Willebrand factor

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3553-3561 ◽  
Author(s):  
O Christophe ◽  
AS Ribba ◽  
D Baruch ◽  
B Obert ◽  
C Rouault ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Point Mutations ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Binding Assays ◽  
Normal Individuals ◽  
Binding Isotherms ◽  
Significant Difference ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract We compared the properties of plasma von Willebrand factor (vWF) from normal individuals and from two patients with type IIA (Glu875Lys) and type IIB (duplication of Met 540) von Willebrand disease (vWD) with the corresponding fully multimerized recombinant proteins. We included cryosupernatant from normal human plasma and type IIA plasma (Cys509Arg). Functions of vWF were analyzed by binding assays to platelets in the presence of ristocetin or botrocetin. Parameters of binding (number of binding sites per vWF subunit, and dissociation constant Kd) were quantitatively estimated from the binding isotherms of 125I-botrocetin or glycocalicin to vWF, independently of the size of the multimers. We found that ristocetin- or botrocetin-induced binding to platelets was correlated in all cases with the size of vWF multimers. In the absence of inducer, only type IIB rvWF Met-Met540 spontaneously bound to platelets. No significant difference of binding of purified botrocetin to vWF was found between normal and patients' plasma, or between wild-type rvWF (rvWF-WT) and rvWF-Lys875. In contrast, affinity of botrocetin for type IIB rvWF Met-Met540 was decreased. Botrocetin-induced binding of glycocalicin to vWF from all plasma and cryosupernatant was similar. Compared with rvWF-WT, binding of glycocalicin to rvWF-Lys875 was normal. In contrast, the affinity for type IIB rvWF Met-Met540 was 10-fold greater. Thus, our data suggest that, in the patients tested, the abnormal IIA phenotype results from the lack of large-sized multimers and is independent of the point mutations. In contrast, the type IIB mutation is directly involved by providing a conformation to the vWF subunits that allows the high molecular weight multimers to spontaneously interact with platelet glycoprotein Ib.

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