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U Budde

Publications and source records attributed to U Budde.

At least 37 records · Page 2Linked to original sources
PubMed2001

Expression and characterization of von Willebrand factor dimerization defects in different types of von Willebrand disease.

Dimerization defects of von Willebrand factor (vWF) protomers underlie von Willebrand disease (vWD) type 2A, subtype IID (vWD 2A/IID), and corresponding mutations have been identified at the 3' end of the vWF gene in exon 52. This study identified and expressed 2 additional mutations in this region, a homozygous defect in a patient with vWD type 3 (C2754W) and a heterozygous frameshift mutation (8566delC) in a patient with vWD type 2A, subtype IIE. Both mutations involve cysteine residues that we propose are possibly essential for dimerization. To prove this hypothesis, transient recombinant expression of each of the 2 mutations introduced in the carboxy-terminal vWF fragment II and in the complete vWF complementary DNA, respectively, were carried out in COS-7 cells and compared with expression of vWD 2A/IID mutation C2773R and the wild-type (WT) sequence in COS-7 cells. Recombinant WT vWF fragment II assembled correctly into a dimer, whereas recombinant mutant fragments were monomeric. Homozygous expression of recombinant mutant full-length vWF resulted in additional dimers, probably through disulfide bonding at the amino-terminal multimerization site, whereas recombinant WT vWF correctly assembled into multimers. Coexpression of recombinant mutant and recombinant WT vWF reproduced the multimer patterns observed in heterozygous individuals. Our results suggest that a common defect of vWF biosynthesis--lack of vWF dimerization--may cause diverse types and subtypes of vWD. We also confirmed previous studies that found that disulfide bonding at the vWF amino-terminal is independent of dimerization at the vWF carboxy-terminal. (Blood. 2001;97:2059-2066)

Adult↗
PubMed2001

Detection of all anti-factor VIII antibodies in haemophilia A patients by the Bethesda assay and a more sensitive immunoprecipitation assay.

Plasmas from 40 haemophilia A patients enrolled in a study by the paediatric group of the German Society on Thrombosis and Hemostasis were tested by the Bethesda assay for inhibitor antibodies and by a more sensitive immunoprecipitation assay (IP) for all antifactor VIII antibodies. Of the 26 severe, 11 moderate and three mild haemophiliacs, 18, two, and none, respectively, had positive Bethesda titres after several factor VIII infusions. In 275 plasmas with Bethesda titres of 0, 0.6--1.0, > 1--5, and > 5--655, the IP responses were 0-238, 0--61, 0--786, and 43--6141, respectively, and a reliable positive IP titre was > 4.2. The overlapping ranges of IP titres indicated large differences in the ratio of inhibitory to noninhibitory antibodies in individual plasmas. In five of seven patients with Bethesda titres of 0.6--1, the IP titres were < 4.2, suggesting a lack of precision of Bethesda titres < or = 1. Detection of the primary immune response was found in only three patients by IP assay before a positive Bethesda assay. This precludes early, reliable testing of which patients will be immunologically responsive. In four patients undergoing immune tolerance therapy, antifactor VIII antibodies were still detectable by the IP assay in the absence of a Bethesda titre, which indicates that antibodies were completely eradicated in none of the patients. Our results show that the use of both the Bethesda and IP assays can provide more accurate detection of antifactor VIII antibodies in all patients.

Antibodies↗
PubMed2001

Von Willebrand factor and von Willebrand disease.

von Willebrand disease (vWD) is caused by quantitative and/or qualitative defects of the von Willebrand factor (vWF), a multimeric high molecular weight glycoprotein. Typically, it affects the primary hemostatic system, which results in a mucocutaneous bleeding tendency simulating a platelet function defect. The vWF promotes its function in two ways: (i) by initiating platelet adhesion to the injured vessel wall under conditions of high shear forces, and (ii) by its carrier function for factor VIII in plasma. Accumulating knowledge of the different clinical phenotypes and the pathophysiological basis of the disease translated into a classification that differentiated between quantitative and qualitative defects by means of quantitative and functional parameters, and by analyzing the electrophoretic pattern of vWF multimers. The advent of molecular techniques provided the opportunity for conducting genotype-phenotype studies which have recently helped, not only to elucidate or confirm important functions of vWF and its steps in post-translational processing, but also many disease causing defects. Acquired von Willebrand syndrome (avWS) has gained more attention during the recent years. An international registry was published and recommendation by the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis in 2000. It concluded that avWS, although not a frequent disease, is nevertheless probably underdiagnosed. This should be addressed in future prospective studies. The aim of treatment is the correction of the impaired hemostatic system of the patient, ideally including the defects of both primary and secondary hemostasis. Desmopressin is the treatment of choice in about 70% of patients, mostly with type 1, while the others merit treatment with concentrates containing vWF.

Clinical Laboratory Techniques↗
PubMed2001

A molecular approach to the classification of von Willebrand disease.

The marked heterogeneity of von Willebrand disease was already recognized by von Willebrand in 1926. The accumulating knowledge of the different clinical phenotypes and the pathophysiological basis of the disease was translated into a classification that differentiated between quantitative and qualitative defects by means of quantitative and functional parameters and by analysing the electrophoretic pattern of von Willebrand factor multimers. The increasing number of different von Willebrand disease phenotypes required a revision of the nomenclature at a time when only a few types of von Willebrand disease had already been analysed at the molecular level. Consequently, the molecular data played only a minor role in the revised classification. Given the pronounced, even intra-individual, variation in the manifestation of von Willebrand disease and the diagnostic difficulties caused by a non-standardized methodology, it is clear that biochemical methods alone are insufficient for a clear classification. The advent of molecular techniques provided the opportunity for genotype-phenotype studies that recently helped to elucidate or confirm not only the important functions of von Willebrand factor and the steps of its post-translational processing, but also many disease-causing defects. The reproducible correlation between certain phenotypes and particular mutations can now be used for a molecular approach towards a final classification of von Willebrand disease, equally useful for the clinician and for research requirements.

Genetic Variation↗
PubMed2001

Acquired von Willebrand syndromes: clinical features, aetiology, pathophysiology, classification and management.

Acquired von Willebrand syndrome (AVWS) associated with hypothyroidism is of type I, results from a decreased synthesis of factor VIII and von Willebrand factor (VWF), responds to desmopressin with normal half-life times for factor VIII and VWF parameters, and disappears after treatment with I-thyroxine. AVWS type I or III, which occurs in a minority of patients with Wilms' tumour in the complete absence of an inhibitor against VWF and no absorption of factor VIII or VWF onto nephroblastoma cells, responds to chemotherapy and/or tumour resection. Hyaluronic acid produced by nephroblastoma cells may be the causative factor in atypical AVWS in Wilms' tumour. AVWS associated with thrombocythaemia of various myeloproliferative disorders is characterized by normal factor VIII and von Willebrand factor antigen (VWF: Ag) levels and a selective deficiency of functional ristocetin co-factor activity (VWF: RCo) and collagen-binding activity (VWF: CBA). AVWS type II in thrombocythaemia is caused by a platelet-dependent proteolysis of large VWF multimers, given the inverse relationship between platelet count and large VWF multimers in plasma and specific increases in the number of proteolytic VWF fragments in plasma. The laboratory findings of AVWS associated with systemic lupus erythematosus or IgG benign monoclonal gammopathy are characterized by a prolonged bleeding time and activated partial thromboplastin time, decreased or absent ristocetin-induced platelet activity, low to very low levels of factor VIII coagulant activity (mean 15%), VWF: Ag (mean 10.7%) and VWF: RCo (mean 6.2%), and a type II multimeric pattern of VWF. Neutralizing and non-neutralizing anti-VWF autoantibodies, usually IgG, have been detected in patient plasma either free or tightly bound to the intermediate and high molecular weight VWF factor VIII particles. The bound auto antibody-antigen complex is rapidly cleared from the circulation, resulting in low levels of factor VIII, VWF parameters as documented by a poor response to desmopressin and VWF factor VIII concentrate. High-dose intravenous immunoglobulin transiently corrects the factor VIII coagulant and VWF levels, lasting for a few weeks in AVWS type II associated with systemic lupus erythematosus or IgG benign monoclonal gammopathy. Prednisolone is effective in AVWS associated with autoimmune disorder. Prednisolone and chemotherapy will not affect AVWS associated with IgG benign monoclonal gammopathy because the monoclonal IgG protein remains to act as an anti-VWF autoantibody. An absorption of VWF to malignant cells has been documented in a few patients with various lymphoproliferative disorders or adrenal carcinoma and suggested to result in a depletion of VWF. The clinical picture of AVWS associated with early-stage IgG multiple myeloma, chronic lymphocytic leukaemia or non-Hodgkin's lymphoma without a paraprotein or no detectable underlying disorder is similar to that of AVWS type II in IgG benign monoclonal gammopathy but poorly documented with regard to the underlying immune mechanism of AVWS. The mechanical destruction of large VWF multimers may be of relevance in conditions in which the shear rate of flowing blood is increased, as may occur in cases of aortic stenosis, other heart valve defects or stenosed vessels. Drug-induced AVWS has been described in association with the use of pesticides valproic acid, ciprofloxacin, griseofulvin, tetracycline, thrombolytic agents and hydroxyethyl starch.

Hematologic Tests↗
PubMed2001

Quantification and facilitated comparison of von Willebrand factor multimer patterns by densitometry.

The analysis of von Willebrand factor (vWF) multimers is an important laboratory tool for distinguishing among the numerous subtypes of von Willebrand disease (vWD). Comparability and reproducibility of this method are insufficient; standardization and external references are pending. Interlaboratory comparison of results therefore may be difficult. We applied densitometry to obtain a reproducible quantification of vWF multimer patterns in healthy donors, patients with vWD variants, and factor VIII/vWF concentrates to improve the reproducibility and comparability of vWF multimer analysis. Multimers were separated and visualized luminographically on x-ray films. Films were scanned and evaluated by densitometry. The variation inherent in vWF multimer analysis and the range of the normal could be quantified. In vWD variants and factor VIII/vWF concentrates, densitometry could quantify and visualize alterations of vWF multimer patterns and facilitate their comparison. Densitometry permits a precise quantitative comparison of sample patterns to a reference plasma. It could be a valuable tool offering reproducible quantification and additional visualization of normal and pathologic vWF multimer patterns, facilitating their comparison and contributing to a standardization of vWF multimer analysis.

Adult↗
PubMed2000

Dietary intake of lead, cadmium, copper and zinc by children from the German North Sea island Amrum.

The dietary intake of metals was studied in seven male and seven female children at the age of 1.5 to 5.3 years living in a remote area of Germany, the North Sea island Amrum. The dietary intake of lead and cadmium was measured by a seven-day-duplicate study using atomic absorption spectrometry. The dietary intake of copper and zinc were calculated from food diaries. The median lead and cadmium intakes were 2.1 micrograms/(kgbw x week) [range: 0.63-5.1 micrograms/(kgbw x week)] and 2.7 micrograms/(kgbw x week) [range: 1.7-4.4 micrograms/(kgbw x week)]. The median daily intake of copper and zinc were 1.1 mg/d (range: 0.54-2.5 mg/d) and 5.7 mg/d (range: 2.7-14 mg/d). Compared to the provisional tolerable weekly intake (PTWI) of 25 micrograms/(kgbw x week) proposed by the WHO the dietary intake of lead was low. The median amounted to 8.5% and the maximum to 20% of the PTWI. The cadmium intake was comparatively high. The median amounted to 39% and the maximum to 63% of the PTWI [7 micrograms/(kgbw x week)]. The median intake of copper was in the range of the values recommended by the German Society of Nutrition (0.7-1.0 mg/d and 1.0-1.5 mg/d for children at the age of 1-< 4 years and 4-< 7 years). Twenty-three percent of the calculated intakes were below these values. The median intake of zinc however did not reach the recommended dietary intake of 7 and 10 mg/d for children at the age of 1-< 4 years and 4-< 7 years.

Cadmium↗
PubMed2000

Von Willebrand Disease type 2M "Vicenza" in Italian and German patients: identification of the first candidate mutation (G3864A; R1205H) in 8 families.

Von Willebrand disease type 2M "Vicenza" (VWD 2M V) is characterised by autosomal dominant inheritance, low von Willebrand factor (VWF) and the presence of "supranormal" multimers in plasma. This specific phenotype has been described in Italian and recently also in German patients. The molecular defect is linked to the VWF gene. However, no specific mutations have been identified until now. We analysed the complete coding region and adjacent intron sequences of the VWF gene in Italian families in comparison to German families with VWD 2M V by a PCR-based mutation screening, combined with SSC- and heteroduplex-analysis of exons 2 through 52, followed by direct sequencing. We identified the first heterozygous candidate mutation (G3864A; R1205H) in all affected members of the 7 Italian families and in 1 German patient but not in the unaffected family members nor on 100 chromosomes of normal subjects, suggesting a causal relationship between the mutation and the phenotype. Haplotype identity, with minor deviations in one Italian family, suggests a common but not very recent genetic origin of R1205H.

Female↗
PubMed2000

Acquired von Willebrand syndrome: data from an international registry.

The acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder with laboratory findings similar to those of congenital von Willebrand disease (vWD). Despite the numerous cases reported in the literature until 1999 (n = 266), large studies on AvWS are not available. Moreover, diagnosis of AvWS has been difficult and treatment empirical. These considerations prompted us to organize an international registry. A questionnaire, devised to collect specific information on AvWS, was sent to all the members of the International Society on Thrombosis and Haemostasis (ISTH), who were invited to respond if they had diagnosed cases with the AvWS cases. 156 members answered the questionnaire and 54 of them sent information on 211 AvWS cases from 50 centers. Data were compared with those already published in the literature and 25 cases already described or not correctly diagnosed were excluded. The 186 AvWS cases that qualified for the registry were associated with lymphoproliferative (48%) and myeloproliferative disorders (15%), neoplasia (5%), immunological (2%), cardiovascular (21%) and miscellaneous disorders (9%). Ristocetin cofactor activity (vWF:RCo) or collagen binding activity (vWF:CBA) were usually low in AvWS (median values 20 U/dL, range 3-150), while factor VIII coagulant activity was sometimes normal (median 25 U/dL, range 3-191). FVIII/vWF inhibiting activities were present in only a minority of cases (16%). Bleeding episodes in AvWS were mostly of mucocutaneous type (68%) and were managed by DDAVP (32%), FVIII/vWF concentrates (37%), intravenous immunoglobulins (33%), plasmapheresis (19%), corticosteroids (19%) and immunosuppressive or chemotherapic agents (35%). Based upon the data of this international registry, it appears that AvWS is especially frequent in lympho- or myeloproliferative and cardiovascular diseases. Therefore, AvWS should be suspected and searched with the appropriate laboratory tests especially when excessive bleeding occurs in patients with these disorders. On the basis of the information provided by this registry guidelines for diagnosis and management of the AvWS are given.

Adolescent↗
PubMed1999

DDAVP treatment in a child with von Willebrand disease type 2M.

UNLABELLED: von Willebrand disease (vWD) type 2M is characterized by the decreased platelet-dependent function of the von Willebrand factor (vWF) that is not caused by the absence of HMW vWF multimers. We report here on a 4-year-old boy with vWD type 2M, who underwent adenotomy and paracentesis after correction of his hemostatic defect by stimulation with DDAVP. The decreased basal levels of vWF Antigen (Ag), ristocetin cofactor activity (RiCoF) and collagen binding activity (CBA) (32%, 14% and 9% respectively) could be stimulated to maximum levels of 69%, 70% and 95% 2 h post DDAVP administration. DDAVP was administered in a dosage of 0.4 microg/kg BW intravenously 30 min prior to surgery. No bleeding occurred intra- and perioperatively. vWF multimer analysis revealed supranormal multimers with an abnormal satellite banding pattern. The typical separation by gel electrophoresis into oligomers with a triplet structure was missing even after stimulation with DDAVP. Thus, the functional hemostatic defect was corrected in this patient after DDAVP administration, although the structural abnormalities of the vWF multimers were still persisting. CONCLUSION: In conclusion, type 2M vWD might be effectively treated with DDAVP administration in cases of elective surgery, dispensing with vWF replacement by pooled blood products.

Blood Loss, Surgical↗
PubMed1999

First workshop for detection of heparin-induced antibodies: validation of the heparin-induced platelet-activation test (HIPA) in comparison with a PF4/heparin ELISA.

BACKGROUND: No data exist regarding the inter-laboratory reproducibility of the heparin-induced-platelet-activation (HIPA) test, the most widely used functional assay in Germany for the detection of heparin-induced thrombocytopenia (HIT) antibodies. METHODS: Nine laboratories used an identical protocol to test eight different sera with the HIPA test. Five laboratories also tested the sera with a platelet factor 4 (PF4)/heparin-complex ELISA. Cross-reactivity with danaparoid-sodium was assessed using 0.2 aFXa units instead of heparin in the HIPA test. RESULTS: Two of nine laboratories had no discrepant HIPA test results. Four laboratories differed in one sample, one reported two discrepant results, and two laboratories reported more than two discrepant results. Cross-reactivity with danaparoid-sodium test results differed among laboratories. PF4/heparin ELISA results were identical in all five laboratories. CONCLUSION: The HIPA test requires strict quality control measures. Using both a sensitive functional assay (HIPA test) and a PF4/heparin ELISA will allow detection of antibodies directed to antigens other than PF4/heparin complexes as well as detection of IgM and IgA antibodies with PF4/heparin specificity.

Antibodies↗
PubMed1998

Management of severe chronic thrombocytopenia in von Willebrand's disease type 2B.

Two patients with a long history of unexplained thrombocytopenia, eventually diagnosed with von Willebrand's disease (vWD) type 2B are reported. In one patient with platelet counts of 80 x 10(9)/l 1-desamino-8-D-arginine vasopressin (DDAVP) had a favourable effect during bleeding episodes. The second patient received intermediate purity von Willebrand's factor (vWF)/factor VIII concentrate (Haemate HS), which helped haemostasis during tooth extraction. It increased platelet counts from 15 to 30 x 10(9)/l, whereas platelet transfusions produced no increase, nor prevented severe bleeding during abdominal surgery. Thus the treatment of vWD type 2B might depend on the degree of thrombocytopenia. It is recommended that in patients with mild to moderately decreased platelet counts, DDAVP treatment can be tried, whereas in patients with severely decreased platelet counts intermediate purity vWF/factor VIII concentrate substitution is preferred. In addition, vWD type 2B should be considered in the differential diagnosis of any child with chronic thrombocytopenia as the treatment strategy is different.

Adolescent↗
PubMed1997

New families with von Willebrand disease type 2M (Vicenza).

The variant von Willebrand disease (vWd) variant type 2M (Vicenza) was identified in 13 patients of 7 unrelated families. 11 patients were from different parts of germany and 2 patients from Turkey. Hitherto this variant of vWd has been described only in two families originating from the province of Vicenza in Northern Italy. Characteristically this type of vWd shows the supranormal multimers of von Willebrand factor (vWf) in plasma similar to those seen in normal plasma after desmopressin infusion. Clinically, the patients present with bleeding symptoms. Other laboratory abnormalities include reduced values for vWf antigen (vWf: Ag), factor VIII coagulant activity (VII:C), ristocetin cofactor activity (RiCof) and collagen binding activity (vWf: CBA). The hereditary transmission of this variant is consistent with an autosomal dominant mode of inheritance. The patients with vWd type 2M (Vicenza) could be allocated into two subgroups: type "platelet normal" with normal vWf properties in platelets and type "platelet low" with reduced vWf: Ag levels in platelets.

Adult↗