The Relationship Between The Multimeric Structure Of F VIII-VWF And The Facilitation Of Platelet Adhesion To Human Subendothelium (Von Willebrand Factor Activity VWF-A)

1981 ◽  
Author(s):  
Jan J Sixma ◽  
Kjell S Sakariassen ◽  
Piet A Bolhuis
Keyword(s):  
High Purity ◽  
Human Platelets ◽  
Gel Chromatography ◽  
Absolute Requirement ◽  
Mild Reduction ◽  
Agarose Electrophoresis ◽  
Von Willebrand ◽  
The Relationship ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

The relation between the VWF-A of F VIII-VWF and its multimeric structure was studied in an annular perfusion chamber according to Baumgartner, with a steady flow system. 51Cr-labelled aspirin treated human platelets and human post mortem renal arteries were employed. F VIII-VWF was purified from cryoprecipitate by agarose gel chromatography and radiolabelled by the lactoperoxydase method. The multimeric distribution was determined by SDS-agarose electrophoresis. Five different commercial high purity concentrates contained multimers between 0.5 and 3.5 x 106 mol wt. None of these concentrates had VWF-A at ristocetin cofactor activities (RIC0F-A) of 1.0 u/ml. A low potency concentrate with mul- timers in the same mol wt range had normal VWF-A. Mild reduction (dithioerythritol-DTE ≤ 2mM) caused a shift in , mol wt range from 3.0 - 20.0 × 106 towards 0.5 - 2.0 × 106 with little decrease in RIC0F-A and VWF-A. Reduction with 10 mM DTE produced multimers of 1.5 and 0.5 × 106 without RICOF-A and VWF-A, but binding normally to the vessel wall. The void volume peak of 125I-VIII-VWF was rechromatographed on Sepharose-2B and arbitrarily divided in fractions A: mol wt 8,0 - 18.0 × 106 ;B: mol wt 4.5 - 11.0 × 106 ; and C: mol wt 2.5 - 6.5 × 106 . Binding of 125I-VIII-VWF to the subendothelium was highest for A, intermediate for B and lowest for C. Correction for mean mol wt showed that almost equal numbers of molecules bound from all three fractions. When the quantity of bound VIII-VWF was thus expressed, all fractions had a similar relative VWF-A.These data indicate that high purity concentrates do not correct the bleeding time at normal RICOF-levels, because they lack VWF-A. Multimers of high mol wt normally carry both RICOF-A and VWF-A, but the high mol wt is no absolute requirement. These data are in agreement with the notion that VWF-A resides on a specific polypeptide chain in the molecule.

scholarly journals Asialo-von Willebrand factor inhibits platelet adherence to human arterial subendothelium: discrepancy between ristocetin cofactor activity and primary hemostatic function

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 1084-1089 ◽  
Author(s):  
JB Lawrence ◽  
HR Gralnick
Keyword(s):  
Von Willebrand Factor ◽  
Whole Blood ◽  
Specific Activity ◽  
Human Platelets ◽  
Primary Hemostasis ◽  
Platelet Adherence ◽  
Wall Shear ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

Abstract Platelet adherence at high wall shear rates requires plasma von Willebrand factor (vWF). Clinically, the ristocetin cofactor (RCof) activity is the only widely available assay for vWF function. When purified vWF is treated with neuraminidase to yield asialo-vWF (AS- vWF), its RCof activity is increased by 20% to 40%. AS-vWF binds to normal human platelets independently of ristocetin and induces platelet aggregation in the presence of fibrinogen. To determine whether AS-vWF also shows an enhanced capacity to support platelet adherence to subendothelium, we used the Baumgartner technique. Intact vWF, AS-vWF, or AS-vWF treated with beta-galactosidase (asialo, agalacto-vWF; AS,AG- vWF) was added to normal citrated whole blood before perfusion over human umbilical artery segments (wall shear rate, 2,600 sec-1). Four micrograms per milliliter AS-vWF caused a 69% reduction in total platelet adherence compared with citrated whole blood (P less than .001), and 4 micrograms/mL AS,AG-vWF led to a 48% reduction (P less than .005). With 4 micrograms/mL intact vWF, the platelet adherence values were not significantly different from the controls. No significant differences in subendothelial platelet thrombi or postperfusion platelet counts were evident among any of the groups. In reconstituted afibrinogenemic perfusates, 4 micrograms/mL AS-vWF caused a 42% reduction in platelet adherence (P less than .05). Thus, AS-vWF is a potent inhibitor of platelet adherence, despite its enhanced RCof specific activity. Abnormalities in vWF carbohydrate may play a role in impaired primary hemostasis in some patients with von Willebrand's disease.

scholarly journals Fluctuations in Factor VIII Procoagulant, Antigen and Von Willebrand Factor in Normal Individuals

1977 ◽  
Author(s):  
H.C. Yang ◽  
C. Vaudreuil
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Normal Male ◽  
Normal Individuals ◽  
Factor Viii Antigen ◽  
The Mean ◽  
Von Willebrand ◽  
The Relationship ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

Fluctuations in the relationship among factor VIII procoagulant (VIIIC), factor VIII antigen (VIIIAG) and von Willebrand factor (vWf, ristocetin cofactor) were studied in two normal females (A&B) and one normal male (C). Biweekly fasting morning plasma samples were obtained over a three week period and assayed on 2 different days. The mean VIIIC/VIIIAG, VIIIC/vWf and VIIIAG/vWf ratios were not significantly different from each other (p>.05) in each of the subjects. However, there were marked day-to-day changes in the three ratios as indicated by the ranges.The results demonstrate that although the ratios among factor VIII procoagulant, factor VIII antigen and von Willebrand factor are relatively fixed, there are significant day-to-day fluctuations.

scholarly journals Asialo-von Willebrand factor inhibits platelet adherence to human arterial subendothelium: discrepancy between ristocetin cofactor activity and primary hemostatic function

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 1084-1089
Author(s):  
JB Lawrence ◽  
HR Gralnick
Keyword(s):  
Von Willebrand Factor ◽  
Whole Blood ◽  
Specific Activity ◽  
Human Platelets ◽  
Primary Hemostasis ◽  
Platelet Adherence ◽  
Wall Shear ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

Platelet adherence at high wall shear rates requires plasma von Willebrand factor (vWF). Clinically, the ristocetin cofactor (RCof) activity is the only widely available assay for vWF function. When purified vWF is treated with neuraminidase to yield asialo-vWF (AS- vWF), its RCof activity is increased by 20% to 40%. AS-vWF binds to normal human platelets independently of ristocetin and induces platelet aggregation in the presence of fibrinogen. To determine whether AS-vWF also shows an enhanced capacity to support platelet adherence to subendothelium, we used the Baumgartner technique. Intact vWF, AS-vWF, or AS-vWF treated with beta-galactosidase (asialo, agalacto-vWF; AS,AG- vWF) was added to normal citrated whole blood before perfusion over human umbilical artery segments (wall shear rate, 2,600 sec-1). Four micrograms per milliliter AS-vWF caused a 69% reduction in total platelet adherence compared with citrated whole blood (P less than .001), and 4 micrograms/mL AS,AG-vWF led to a 48% reduction (P less than .005). With 4 micrograms/mL intact vWF, the platelet adherence values were not significantly different from the controls. No significant differences in subendothelial platelet thrombi or postperfusion platelet counts were evident among any of the groups. In reconstituted afibrinogenemic perfusates, 4 micrograms/mL AS-vWF caused a 42% reduction in platelet adherence (P less than .05). Thus, AS-vWF is a potent inhibitor of platelet adherence, despite its enhanced RCof specific activity. Abnormalities in vWF carbohydrate may play a role in impaired primary hemostasis in some patients with von Willebrand's disease.

Von Willebrand Factor Multimer Patterns in Pregnancy-Induced Hypertension

1989 ◽  
Vol 62 (02) ◽  
pp. 715-717 ◽  
Author(s):  
B Brenner ◽  
E Zwang ◽  
M Bronshtein ◽  
U Seligsohn
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Control Group ◽  
Pregnancy Induced Hypertension ◽  
Induced Hypertension ◽  
Agarose Electrophoresis ◽  
Quantitative Changes ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

SummaryMicroangiopathy and disseminated platelet aggregation have been reported in thrombotic thrombocytopenic purpura (TIP) and pregnancy-induced hypertension (PIH). Since unusually large von Willebrand factor (vWF) multimers have been implicated in the evolvement of TTP, we analyzed factor VIII/vWF parameters in patients with PIH. Mean vWF: Ag level was significantly higher in 27 patients with PIH as compared to 20 matched healthy pregnant women (358 ± 160 u/dl vs. 274 ± 125 u/dl, p < 0.05). Moreover, plasma vWF: Ag levels and the ratio of vWF: Ag to factor VIII were found to be linearly correlated to the severity of PIH. In contrast, no significant differences in mean levels of factor VIII and ristocetin cofactor were observed between these groups. Crossed immunoelectrophoresis of vWF revealed a higher incidence of a pre-peak and an increased migration index in the PIH group as compared to the control group (60% vs. 44% and 1.27 ± 0.26 vs. 1.19 ± 0.18, p < 0.01 respectively). Analysis of plasma vWF multimer patterns by 1.4% agarose electrophoresis in 0.1% SDS revealed excessive amounts of large, medium and small size multimers in the PIH patients. Conceivably, the quantitative changes in vWF multimers reflect endothelial injury and may play a role in the microangiopathy observed in PIH.

Visualization of von Willebrand Factor Multimers by Enzyme-Conjugated Secondary Antibodies

1986 ◽  
Vol 55 (02) ◽  
pp. 276-278 ◽  
Author(s):  
F Brosstad ◽  
Inge Kjønniksen ◽  
B Rønning ◽  
H Stormorken
Keyword(s):  
Von Willebrand Factor ◽  
Chromogenic Substrate ◽  
Agarose Electrophoresis ◽  
Secondary Antibodies ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Beta Galactosidase

SummaryA method for visualization of the multimeric forms of von Willebrand Factor (vWF) in plasma and platelets is described. The method is based upon: 1) Separation of the vWF multimers by SDS-agarose electrophoresis, 2) Subsequent blotting of the vWF multimers onto nitrocellulose, 3) Immunolocalization and visualization of the vWF pattern by the sequential incubation of the blot with a) primary vWF antiserum, b) peroxidase- or beta-galactosidase-conjugated secondary antibodies and a relevant chromogenic substrate.

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.

Interactions of Purified Rat Factor VIII/von Willebrand Factor with Rat and Human Platelets – Effect of Albumin and Ristocetin

1984 ◽  
Vol 52 (01) ◽  
pp. 057-059 ◽  
Author(s):  
E Dejana ◽  
M Furlan ◽  
B Barbieri ◽  
M B Donati ◽  
E A Beck
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Rat Plasma ◽  
Human Platelets ◽  
High Concentrations ◽  
Low Sensitivity ◽  
Von Willebrand ◽  
Induced Aggregation ◽  
Willebrand Factor ◽  
Rat Platelets

SummaryRat platelets do not respond to ristocetin in their own plasma nor do they aggregate in the presence of bovine or porcine factor VIII von Willebrand factor (F VIII R:WF) or human F VIII R:WF in presence of ristocetin. However, rat plasma supports ristocetin induced aggregation of washed human platelets. In this study we report on purification of rat F VIII R:WF from cryoprecipitate. Similarly to porcine or bovine material, purified rat F VIII R:WF induced aggregation of human washed fixed platelets. This effect was enhanced by addition of ristocetin and was not modified by addition of albumin. Rat washed platelets were aggregated by ristocetin in the presence of rat or human F VIII R:WF provided that high concentrations of ristocetin are added in a system essentially free of extraneous proteins. Increasing concentrations of albumin dramatically reduced the ability of ristocetin to aggregate rat platelets while human platelet aggregation by human or rat F VIII R:WF was only moderately affected.These studies show that rat F VIII R:WF can interact with rat and human platelets. The lack of response of rat platelets to ristocetin in their own plasma is most likely due to a low sensitivity of rat platelets to this drug and to an inhibitory activity of plasma proteins on this reaction.

Endothelial Dysfunction and Inflammatory Markers of Vascular Disease

2020 ◽  
Vol 19 (3) ◽  
pp. 243-249 ◽  
Author(s):  
Sevket Balta
Keyword(s):  
Endothelial Dysfunction ◽  
Vascular Disease ◽  
Inflammatory Markers ◽  
Vascular Diseases ◽  
Intima Media Thickness ◽  
Carotid Intima Media Thickness ◽  
Non Invasive ◽  
Von Willebrand ◽  
The Relationship ◽  
Willebrand Factor

: Vascular diseases are the main reason for morbidity and mortality worldwide. As we know, the earlier phase of vascular diseases is endothelial dysfunction in humans, the endothelial tissues play an important role in inflammation, coagulation, and angiogenesis, via organizing ligand-receptor associations and the various mediators’ secretion. We can use many inflammatory non-invasive tests (flowmediated dilatation, epicedial fat thickness, carotid-intima media thickness, arterial stiffness and anklebrachial index) for assessing the endothelial function. In addition, many biomarkers (ischemia modified albumin, pentraxin-3, E-selectin, angiopoietin, endothelial cell specific molecule 1, asymmetrical dimethylarginine, von Willebrand factor, endothelial microparticles and endothelial progenitor cells) can be used to evaluate endothelial dysfunction. We have focused on the relationship between endothelial dysfunction and inflammatory markers of vascular disease in this review.

Management of Type 2B von Willebrand Disease during Pregnancy

2017 ◽  
Vol 137 (2) ◽  
pp. 89-92 ◽  
Author(s):  
David McLaughlin ◽  
Ron Kerr
Keyword(s):  
Autosomal Dominant ◽  
Case Reports ◽  
Management Plan ◽  
Von Willebrand Disease ◽  
Best Management ◽  
First Case ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor ◽  
Platelet Transfusions

Type 2B von Willebrand disease is a rare bleeding condition resulting in thrombocytopenia and a reduction in large VWF multimers. It usually has an autosomal dominant pattern of inheritance. We report the management of a patient with type 2B von Willebrand disease, whose diagnosis was confirmed by demonstration of a R1306W mutation, through her first pregnancy. The patient's von Willebrand factor (VWF) antigen and VWF ristocetin cofactor levels rose throughout pregnancy, with an associated drop in the platelet count. The patient was successfully managed through labour to a surgical delivery with VWF concentrate, platelet transfusions and tranexamic acid. The patient delivered a male baby who was found to have inherited type 2B von Willebrand disease and had a significant cephalhaematoma at delivery. The baby was managed with VWF concentrate and platelet transfusions and made a full recovery. There is a lack of evidence to guide the best management of pregnant patients with type 2B von Willebrand disease. We adopted a pragmatic management plan, in keeping with other published case reports. To the best of our knowledge, this is the first case report in which the child was found to have inherited type 2B von Willebrand disease and encountered bleeding problems, making this case unique amongst the published literature.

Sign in / Sign up

Export Citation Format

Share Document