scholarly journals Subunit composition of plasma von Willebrand factor in patients with the myeloproliferative syndrome

Blood ◽  
1986 ◽  
Vol 68 (6) ◽  
pp. 1213-1217 ◽  
Author(s):  
U Budde ◽  
JA Dent ◽  
SD Berkowitz ◽  
ZM Ruggeri ◽  
TS Zimmerman
Keyword(s):  
Von Willebrand Factor ◽  
Bleeding Time ◽  
Polyacrylamide Gel Electrophoresis ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Prolonged Bleeding Time ◽  
Myeloproliferative Syndrome ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract In order to evaluate the role of proteolysis in acquired von Willebrand's disease (vWD) associated with the myeloproliferative syndrome, we have determined the relative quantity of von Willebrand factor (vWF) fragments as compared with the intact 225 kDa subunit in four patients. The plasma vWF of each individual lacked large multimers; each had a prolonged bleeding time; and both platelet and leukocyte counts were elevated. Plasma was obtained from blood drawn into 1 mmol/L leupeptin, 6 mmol/L N-ethylmaleimide, and 5 mmol/L EDTA to prevent in vitro proteolysis. vWF was isolated from plasma by immunoadsorbent chromatography, reduced, subjected to SDS-5% polyacrylamide gel electrophoresis, and immunoblotted with a mixture of 55 anti-vWF monoclonal antibodies. In three patients with essential thrombocytosis (ET) the 176 and 140 kDa fragments were increased in proportion to the intact 225 kDa subunit indicating increased proteolysis. Treatment of one ET patient with CCNU (Lomustine) decreased the platelet count and, to a lesser extent, the white blood cell count. This was associated with a correction of the bleeding time, a partial correction of the multimeric abnormality, and a lessening of vWF cleavage. In a patient with polycythemia rubra vera (PRV) the proportion of the 176 kDa fragment was increased to the upper limit of normal but there was no definite evidence of increased proteolysis. These studies provide evidence that proteolysis plays a role in the acquired von Willebrand's disease associated with the myeloproliferative syndrome. However, other mechanisms must also be considered.

scholarly journals Subunit composition of plasma von Willebrand factor in patients with the myeloproliferative syndrome

Blood ◽  
1986 ◽  
Vol 68 (6) ◽  
pp. 1213-1217 ◽  
Author(s):  
U Budde ◽  
JA Dent ◽  
SD Berkowitz ◽  
ZM Ruggeri ◽  
TS Zimmerman
Keyword(s):  
Von Willebrand Factor ◽  
Bleeding Time ◽  
Polyacrylamide Gel Electrophoresis ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Prolonged Bleeding Time ◽  
Myeloproliferative Syndrome ◽  
Von Willebrand ◽  
Willebrand Factor

In order to evaluate the role of proteolysis in acquired von Willebrand's disease (vWD) associated with the myeloproliferative syndrome, we have determined the relative quantity of von Willebrand factor (vWF) fragments as compared with the intact 225 kDa subunit in four patients. The plasma vWF of each individual lacked large multimers; each had a prolonged bleeding time; and both platelet and leukocyte counts were elevated. Plasma was obtained from blood drawn into 1 mmol/L leupeptin, 6 mmol/L N-ethylmaleimide, and 5 mmol/L EDTA to prevent in vitro proteolysis. vWF was isolated from plasma by immunoadsorbent chromatography, reduced, subjected to SDS-5% polyacrylamide gel electrophoresis, and immunoblotted with a mixture of 55 anti-vWF monoclonal antibodies. In three patients with essential thrombocytosis (ET) the 176 and 140 kDa fragments were increased in proportion to the intact 225 kDa subunit indicating increased proteolysis. Treatment of one ET patient with CCNU (Lomustine) decreased the platelet count and, to a lesser extent, the white blood cell count. This was associated with a correction of the bleeding time, a partial correction of the multimeric abnormality, and a lessening of vWF cleavage. In a patient with polycythemia rubra vera (PRV) the proportion of the 176 kDa fragment was increased to the upper limit of normal but there was no definite evidence of increased proteolysis. These studies provide evidence that proteolysis plays a role in the acquired von Willebrand's disease associated with the myeloproliferative syndrome. However, other mechanisms must also be considered.

Von Willebrand’s Disease caused by Compound Heterozygosity for a Substitution Mutation (T1156M) in the D3 Domain of the Von Willebrand Factor and a Stop Mutation (Q2470X)

2002 ◽  
Vol 88 (09) ◽  
pp. 421-426 ◽  
Author(s):  
Stefan Lethagen ◽  
Christina Isaksson ◽  
Charlotta Schaedel ◽  
Lars Holmberg
Keyword(s):  
Von Willebrand Factor ◽  
Null Allele ◽  
Dependent Manner ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Stop Mutation ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryHereditary defects of the von Willebrand factor (VWF) gene cause von Willebrand’s disease (VWD) which shows great variability dependent on the nature and location of the mutation. We here describe the characteristics of a substitution of methionine for threonine 1156 in the D3 domain of the VWF, i.e. the domain involved in the intracellular multimerization of pro-VWF dimers. A VWD patient with severe symptoms was a compound heterozygote for the T1156M mutation and a null allele (Q2470X) on the other chromosome. This led to marked reduction of plasma VWF concentration to about 0.05 U/ml and an abnormality of VWF multimers as in type 2A VWD. Expression in vitro of the mutation demonstrated that 1156M-VWF is secreted from COS-7 cells in a much reduced amount and lacking large multimers. When coexpressed with normal VWF 1156M-VWF decreased the secretion of normal VWF in a dose-dependent manner, the secreted VWF showing all the multimers. Two relatives of the propositus were single heterozygotes for the T1156M mutation and were either asymptomatic or had the manifestations of mild type 1 VWD. The expression data and studies of platelet VWF indicate that the T1156M mutation results in intracellular retention of VWF rather than impaired synthesis. Three other members of the family were heterozygotes for the Q2470X mutation and demonstrated the variable expressivity of a null allele.

scholarly journals DDAVP in type IIa von Willebrand's disease

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 465-468 ◽  
Author(s):  
HR Gralnick ◽  
SB Williams ◽  
LP McKeown ◽  
ME Rick ◽  
P Maisonneuve ◽  
...  
Keyword(s):  
Factor Viii ◽  
Protease Inhibitors ◽  
Von Willebrand Factor ◽  
Bleeding Time ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Time Period ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

Abstract 1-D-Amino(8-D-arginine)-vasopressin (DDAVP) infusion in three patients with type IIa von Willebrand's disease (vWD) resulted in a normalization of the factor VIII coagulant, factor VIII-related antigen, and von Willebrand factor (vWF) (ristocetin cofactor) activities and the bleeding time. The normalization of these hemostatic parameters persisted for four hours. Over the same time period there was a marked increase in the quantity of the vWF multimers when blood was collected in the presence of protease inhibitors. The vWF multimers present were even larger than the normal. When blood was collected in the absence of protease inhibitors, a smaller increase in the plasma vWF multimers was observed and fewer of the intermediate and larger vWF multimers were seen; multimers larger than those present in normal plasma were not visualized. The platelet vWF multimers and activities did not change with or without inhibitors. These studies suggest that there is a subgroup of patients with type IIa vWD who respond to DDAVP with complete normalization of their hemostatic abnormalities and whose vWF is sensitive to proteolysis.

scholarly journals Multimeric composition of factor VIII/von Willebrand factor following administration of DDAVP: implications for pathophysiology and therapy of von Willebrand's disease subtypes

Blood ◽  
1982 ◽  
Vol 59 (6) ◽  
pp. 1272-1278 ◽  
Author(s):  
ZM Ruggeri ◽  
PM Mannucci ◽  
R Lombardi ◽  
AB Federici ◽  
TS Zimmerman
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Resting State ◽  
Bleeding Time ◽  
Type I ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Plasma Factor ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract We have studied the modifications in the multimeric composition of plasma factor VIII/von Willebrand factor and the bleeding time response following administration of 1-Deamino-[8-D-arginine]-Vasopressin (DDAVP) to patients with different subtypes of von Willebrand's disease. In type I, all multimers were present in plasma in the resting state, though they were decreased in concentration. Administration of DDAVP resulted in an increased concentration of these forms as well as the appearance of larger forms than were previously present. There was concomitant correction of the bleeding time. In type IIA, large multimers were absent in the resting state, and although DDAVP induced an average threefold increase in the plasma concentration of factor VIII/von Willebrand factor, the larger multimers did not appear and the bleeding time, although shortened, was not corrected. In contrast, the larger multimers that were also absent from type IIB plasma in the resting state rapidly appeared following DDAVP administration. However, their appearance was transitory and the bleeding time, as in IIA patients, was shortened but not corrected. The characteristic multimeric composition of platelet factor VIII/von Willebrand factor in given subtypes predicted the alteration in plasma factor VIII/von Willebrand factor induced by DDAVP. These studies provide evidence that the different subtypes of von Willebrand's disease represent distinct abnormalities of factor VIII/von Willebrand factor. They also suggest that complete hemostatic correction following DDAVP can be routinely expected only in type I von Willebrand's disease, and only if factor VIII/von Willebrand factor can be raised to normal levels.

scholarly journals Platelet von Willebrand factor: an important determinant of the bleeding time in type I von Willebrand's disease

Blood ◽  
1986 ◽  
Vol 68 (1) ◽  
pp. 58-61 ◽  
Author(s):  
HR Gralnick ◽  
ME Rick ◽  
LP McKeown ◽  
SB Williams ◽  
RI Parker ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Bleeding Time ◽  
Time Factors ◽  
Type I ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen ◽  
Ristocetin Cofactor

Abstract We studied 17 patients with moderate to mild type I von Willebrand's disease (vWd) and correlated the bleeding time with the plasma von Willebrand factor antigen (vWf Ag), the plasma vWf activity (ristocetin cofactor), the platelet vWf Ag, and the platelet vWf activity. We found an excellent correlation between the bleeding time and the platelet vWf activity and, to a lesser extent, between the bleeding time and the platelet vWf Ag. The length of the bleeding time was inversely proportional to the level of the platelet vWf (P less than .001) or, to a lesser extent, the platelet vWf Ag (P less than .05). The plasma vWf Ag and activity did not correlate significantly with the bleeding time. These studies indicate that the platelet vWf is one of the important bleeding time factors in type I vWd and that the platelet vWf plays an important role in the early steps of hemostasis.

HETEROGENOUS RESPONSES TO CRYOPRECIPITATE AND DDAVP IN TYPE IIA VON WILLEBRAND'S DISEASE (VWD)

1987 ◽  
Author(s):  
J Chediak ◽  
B Maxey ◽  
J Eldridge ◽  
M C Telfer
Keyword(s):  
Von Willebrand Factor ◽  
Selective Reduction ◽  
Autosomal Dominant Disorder ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Prolonged Bleeding Time ◽  
Von Willebrand Factor Antigen ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

Von Willebrand's disease is an autosomal dominant disorder characterized by excessive mucocutaneous bleeding, prolonged bleeding time (BT), and reduce amounts of ristocetin cofactor activity (RiCof). The Von Willebrand factor antigen (VWF:Ag) shows either reduced amounts or no multimers (Types I and III), or a selective reduction of high molecular weight multimers (HMW) (Type IIA and IIB). Variable responses to DDAVP have been reported in IIA VWD suggesting that IIA patients (pts) are a heterogenous group. Some IIA pts may show RiCcf activity after DDAVP infusion even though no HMW multimers are found.Von Willebrand factor antigen, RiCof and BT were analyzed in five pts (2 females and 3 males) known to have Type IIA VWD. Baseline values shov/ed marked reductions of RiCof (less than 13% of normal), BT greater than 15 minutes, faster immunoelectrophoresis of VWF:Ag and absent HMW multimers. Immunoelectrophoresis of VWF:Ag by the Laurell technique gave variable amounts ranging from 10 to 125% or normal. Three adult pts received DDAVP (Stimate) or cryoprecipitate (cryo) and the responses on abnormal parameters were assessed up to 48 hours. In two pts the BT corrected with cryo, whereas in the third patient the correction was minimal. The three pts showed a normal decay of both VWF:Ag or RiCof after cryo. However, after DDAVP the decay of VWF:Ag and RiCof was similar to that after cryo in one patient and more rapid in two patients.In these two patients, the data would be compatible with the rapid proteolysis of endogenoue VWF released by the patient's endothelial cells, whereas the exogenous VWF given as cryo showed normal survival in the patient's blood.

scholarly journals DDAVP in type IIa von Willebrand's disease

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 465-468 ◽  
Author(s):  
HR Gralnick ◽  
SB Williams ◽  
LP McKeown ◽  
ME Rick ◽  
P Maisonneuve ◽  
...  
Keyword(s):  
Factor Viii ◽  
Protease Inhibitors ◽  
Von Willebrand Factor ◽  
Bleeding Time ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Time Period ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

1-D-Amino(8-D-arginine)-vasopressin (DDAVP) infusion in three patients with type IIa von Willebrand's disease (vWD) resulted in a normalization of the factor VIII coagulant, factor VIII-related antigen, and von Willebrand factor (vWF) (ristocetin cofactor) activities and the bleeding time. The normalization of these hemostatic parameters persisted for four hours. Over the same time period there was a marked increase in the quantity of the vWF multimers when blood was collected in the presence of protease inhibitors. The vWF multimers present were even larger than the normal. When blood was collected in the absence of protease inhibitors, a smaller increase in the plasma vWF multimers was observed and fewer of the intermediate and larger vWF multimers were seen; multimers larger than those present in normal plasma were not visualized. The platelet vWF multimers and activities did not change with or without inhibitors. These studies suggest that there is a subgroup of patients with type IIa vWD who respond to DDAVP with complete normalization of their hemostatic abnormalities and whose vWF is sensitive to proteolysis.

Ins405AsnPro Mutation in the von Willebrand Factor Propeptide in Recessive Type 2A (IIC) von Willebrand’s Disease

1998 ◽  
Vol 79 (04) ◽  
pp. 718-722 ◽  
Author(s):  
D. Karpman ◽  
C. Isaksson ◽  
A. C. Kristoffersson ◽  
S. Lethagen ◽  
R. Schneppenheim ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
De Novo ◽  
Duplication Event ◽  
Von Willebrand Disease ◽  
In Vitro Mutagenesis ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryThe molecular defects of the von Willebrand factor (vWF) have been studied in the patient in whom the von Willebrand disease phenotype IIC was originally described. A six nucleotide insert, AATCCC, was found in exon 11 of the vWF gene, predicting the insertion of the amino acids asparagine and proline between phenylala-nine 404 and threonine 405 of the vWF propeptide. The mutation was present in one allele. Analysis of amplification products derived from platelet vWF mRNA showed the other allele to be silent. The patient is thus a compound heterozygote for a null allele and the IIC allele, in accord with the recessive mode of inheritance of the IIC phenotype. Family studies indicated the IIC mutation to have occurred de novo, possibly as a result of a duplication event. In vitro mutagenesis and expression in COS-7 cells confirmed the detrimental effect of the mutation on vWF multimer assembly. Taken together with those of earlier studies the present findings suggest that the IIC phenotype may well be exclusively caused by mutations which result in changes of the amino acid sequence in certain regions of the vWF propeptide. Although in the recently revised classification of von Willebrand’s disease variants, the IIC type is included in the 2A category, obviously it constitutes a very distinct subtype.

scholarly journals Acquired von Willebrand's disease in the myeloproliferative syndrome

Blood ◽  
1984 ◽  
Vol 64 (5) ◽  
pp. 981-985 ◽  
Author(s):  
U Budde ◽  
G Schaefer ◽  
N Mueller ◽  
H Egli ◽  
J Dent ◽  
...  
Keyword(s):  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Prolonged Bleeding Time ◽  
Cell Counts ◽  
Myeloproliferative Syndrome ◽  
Fraction I ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Partial Correction ◽  
Ristocetin Cofactor

Abstract An acquired hemorrhagic disorder developed in two patients in association with postsplenectomy thrombocytosis and leukocytosis during the course of the myeloproliferative syndrome. The presence of acquired von Willebrand's disease in these individuals was demonstrated by a decrease or absence of the larger von Willebrand factor (vWF) multimers, alteration of the repeating vWF multimeric “triplet,” decreased ristocetin cofactor activity (vWF:RCo), and prolonged bleeding time. The bleeding stopped in both patients after treatment with either 1-deamino-[8-D-arginine]-vasopressin (DDAVP) or Cohn fraction I. Treatment with thrombocytapheresis and azathioprine or busulfan resulted in reduction of the elevated platelet and white cell counts and was associated with partial correction of the vWF abnormalities and remission of the hemostatic abnormalities. In five additional patients with the myeloproliferative syndrome, but without bleeding symptoms, large multimers of plasma vWF were diminished also. These findings suggest that acquired von Willebrand's disease should be considered when a bleeding diathesis develops during the course of the myeloproliferative syndrome.

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