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1.
Ann Ig ; 34(6): 627-634, 2022.
Article in English | MEDLINE | ID: mdl-35107122

ABSTRACT

Background: The International Standardization Organization operates the world's most widely recognized quality management system standard, the ISO 9001:2015. In the healthcare sector, the adoption of this standard within an organization helps to improve the overall performance and provides a foundation for development and continuous progress. Our study aims to describe the implementation process of a quality management system according to the ISO 9001:2015 standards in an Angiology Unit of an Italian Univer-sity hospital. Methods: The project was structured in 5 operational phases, which were carried out during a time frame of 14 months (March 2018-May 2019) and entailed several improvement actions associated with quality and safety outputs such as clinical management, clinical practice, safety, and patient-centeredness. Results: Implementation of the quality management system led to the improvement of many aspects of the processes performed in the Angiology Unit, both in the outpatient and day hospital setting. Overall, the project positively impacted on systems for patient safety, particularly in communication and data transmis-sion, and clinical leadership. Conclusions: The implementation of the ISO 9001 certification is a process that apparently may seem ex-pensive in terms of resources used, commitment, work, comparison, but it leads to substantial and always progressive improvements in the offer of Services to the user, safety both for the users and for the healthcare personnel involved, in addition to the care processes that translate into significant benefits in terms of quality of care for patients, as well as management savings for the organization.


Subject(s)
Cardiology , Hospitals , Certification , Humans , Patient Safety , Reference Standards
2.
J Thromb Haemost ; 13(2): 228-36, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25425019

ABSTRACT

BACKGROUND: In individuals with borderline von Willebrand factor (VWF) plasma levels, second-level tests are required to confirm or exclude von Willebrand disease (VWD). These tests are time-consuming and expensive. OBJECTIVE: To assess which parameters can predict VWD diagnosis in individuals with borderline VWF levels (30-60 IU dL(-1) ). METHODS: Nine hundred and fifty individuals with bleeding episodes or abnormal coagulation test results were investigated with first-level tests (blood count, prothrombin time, activated partial thromboplastin time, blood clotting factor VIII, VWF ristocetin cofactor activity [VWF:RCo], and VWF antigen), and 93 (62 females and 31 males; median age, 28 years; interquartile range 15-44) had borderline VWF:RCo levels. All underwent second-level investigations to confirm or exclude VWD. A multivariable logistic regression model was fitted with sex, age, bleeding score, family history, VWF:RCo and ABO blood group as predictors, and used to predict VWD diagnosis. RESULTS: Forty-five of the 93 individuals (48%) had VWD (84% type 1). A negative linear relationship between VWF:RCo levels and risk of VWD diagnosis was present, and was particularly evident with blood group non-O [adjusted odds ratio 7.00 (95% confidence interval [CI] 1.48-33.11) for every 5 IU dL(-1) decrease in VWF:RCo]. The other variable clearly associated with VWD diagnosis was female sex (adjusted odds ratio 5.76 [95% CI 1.47-22.53]). The area under the receiver operating characteristic curve of the full logistic model was 0.89 (95% CI 0.82-0.95). CONCLUSIONS: In individuals with borderline VWF, the two strongest predictors of VWD diagnosis are low VWF:RCo levels (particularly in those with blood group non-O) and female sex. This predictive model has a promising discriminative ability to identify patients with borderline VWF levels who are likely to have VWD.


Subject(s)
Blood Coagulation , von Willebrand Diseases/diagnosis , von Willebrand Factor/analysis , Adolescent , Adult , Biomarkers/blood , Blood Cell Count , Chi-Square Distribution , Female , Humans , Linear Models , Logistic Models , Male , Multivariate Analysis , Odds Ratio , Partial Thromboplastin Time , Predictive Value of Tests , Prothrombin Time , Risk Factors , Sex Factors , Young Adult , von Willebrand Diseases/blood
4.
J Thromb Haemost ; 11(7): 1251-9, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23621778

ABSTRACT

INTRODUCTION: We characterized four unrelated patients with von Willebrand disease type 2A/IIE, sharing the same von Willebrand factor (VWF) in-frame deletion (p.[P1127_G1180delinsR];[=]) resulting from exon 26 skipping (Δ26). OBJECTIVES: To identify the VWF mutations and how they caused the mRNA splicing alteration, to evaluate the deletion by in vitro expression studies, and to assess whether or not the heterogeneity of the patients' phenotype might be related to a different degree of expression of the deleted subunit in patient plasma VWF. METHODS: Sequence analysis was performed with patient genomic DNA and platelet mRNA. Semiquantitative RT-PCR was also carried out to compare the expression of the wild-type (WT) and Δ26 alleles in the four patients. In silico analysis was performed with prediction splicing programs. Expression studies were performed to evaluate mutant recombinant VWF (rVWF) (Δ26 and Δ26/WT) as compared with WT rVWF. RESULTS: Three patients shared the synonymous single-nucleotide substitution (SSS) c.[3390C>T];[=], whereas the novel mutation c.[3380-2A>G];[=] was present in the fourth patient. Semiquantitative RT-PCR of platelet mRNA revealed a different ratio of the WT and Δ26 alleles in the patients, consistent with the different VWF:FVIIIB values present in patient plasma. Expression studies confirmed reduced VWF-FVIII binding of rVWF-Δ26/WT. CONCLUSIONS: SSS can induce alternative splicing, and those like c.3390C>T, which impact on the poorly conserved splicing regulatory elements, are difficult to predict, so that their role can be evaluated only by mRNA analysis. Moreover, these mutations seem to have different effects on the efficiency of alternative splicing, producing heterogeneous VWF variants among the four patients.


Subject(s)
Exons , Mutation , RNA Splice Sites , von Willebrand Disease, Type 2/genetics , von Willebrand Factor/genetics , Alternative Splicing , Biomarkers/blood , Blood Platelets/metabolism , Computer Simulation , DNA Mutational Analysis , Genetic Predisposition to Disease , HEK293 Cells , Humans , Phenotype , RNA, Messenger/blood , Reverse Transcriptase Polymerase Chain Reaction , Transfection , von Willebrand Disease, Type 2/blood , von Willebrand Factor/metabolism
5.
Haemophilia ; 19(2): 338-42, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23205618

ABSTRACT

The ristocetin cofactor assay (VWF:RCo) is the reference method for assessing von Willebrand factor (VWF) activity in the diagnosis of von Willebrand's Disease (VWD). However, the assay suffers from poor reproducibility and sensitivity at low levels of VWF and is labour intensive. We have undertaken an evaluation of a new immunoturbidimetric VWF activity (VWF:Ac) assay (INNOVANCE(®) VWF Ac. Siemens Healthcare Diagnostics, Marburg, Germany) relative to an established platelet-based VWF:RCo method. Samples from 50 healthy normal subjects, 80 patients with VWD and 50 samples that exhibited 'HIL' (i.e. Haemolysis, Icterus or Lipaemia) were studied. VWF:Ac, VWF:RCo and VWF:Ag were performed on a CS-analyser (Sysmex UK Ltd, Milton Keynes, UK), all reagents were from Siemens Healthcare Diagnostics. The VWF:Ac assay, gave low intra- and inter-assay imprecision (over a 31-day period, n = 200 replicate readings) using commercial normal (Mean 96.2 IU dL(-1), CV < 3.0%) and pathological (Mean 36.1 IU dL(-1), CV < 3.5%) control plasmas. The normal and clinical samples exhibited good correlation between VWF:RCo (range 3-753 IU dL(-1)) and VWF:Ac (rs = 0.97, P < 0.0001), with a mean bias of 5.6 IU dL(-1). Ratios of VWF:Ac and VWF:RCo to VWF:Ag in the VWD samples were comparable, although VWF:Ac had a superior lower level of detection to that of VWF:RCo (3% and 5% respectively). A subset (n = 97) of VWD and HIL samples were analysed for VWF:Ac at two different dilutions to assess the effect on relative potency, no significant difference was observed (P = 0.111). The INNOVANCE(®) VWF Ac assay was shown to be reliable and precise.


Subject(s)
Enzyme-Linked Immunosorbent Assay/methods , von Willebrand Diseases/diagnosis , von Willebrand Factor/analysis , Antibodies, Monoclonal , Humans , Receptors, GABA-B/metabolism , Reproducibility of Results
6.
J Thromb Haemost ; 9(9): 1744-51, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21726405

ABSTRACT

BACKGROUND: Binding of von Willebrand factor (VWF) multimers of ultra-large size to platelets is considered the triggering mechanism of microvascular thrombosis in thrombotic thrombocytopenic purpura (TTP). OBJECTIVE: To assess the potential of VWF-related measurements as markers of disease activity and severity in TTP. METHODS: VWF antigen (VWF:Ag), platelet glycoprotein-Ib-α binding-conformation (GPIb-α/BC) and multimeric pattern were investigated in 74 patients with acquired TTP during acute disease, remission or both and 73 healthy controls. In patients with both acute and remission samples available, VWF ristocetin co-factor activity (VWF:RCo) and collagen binding (VWF:CB) were also measured. The relationships of study measurements with the presence of acute disease and remission and with markers of disease severity were assessed. RESULTS: VWF:Ag and VWF-GPIb-α/BC were higher in TTP patients than controls (P < 0.001 and 0.004). However, there was no statistically significant difference in VWF-GPIb-α/BC between samples obtained during acute TTP and remission. Larger VWF multimers were frequently lacking in acute TTP patients, who displayed ultra-large multimers at remission. The degree of loss of larger VWF multimers correlated with the degree of abnormality of hemoglobin, platelet counts and serum lactate dehydrogenase (LDH) and was associated with low levels of both VWF:RCo/Ag and VWF:CB/Ag ratios. CONCLUSIONS: In TTP the platelet-binding conformation of VWF is not exclusively present in acute disease, nor is it associated with its clinical and laboratory severity. The loss of larger VWF multimers, accompanied by low VWF:RCo/Ag and VWF:CB/Ag ratio values, represents an index of disease activity and severity of acute TTP in patients with severe ADAMTS-13 deficiency.


Subject(s)
Blood Platelets/physiology , Purpura, Thrombotic Thrombocytopenic/blood , von Willebrand Factor/chemistry , von Willebrand Factor/physiology , ADAM Proteins/blood , ADAM Proteins/deficiency , ADAMTS13 Protein , Acute Disease , Case-Control Studies , Collagen/blood , Humans , Membrane Glycoproteins/blood , Membrane Glycoproteins/chemistry , Platelet Glycoprotein GPIb-IX Complex , Protein Binding , Protein Conformation , Protein Multimerization , Retrospective Studies , von Willebrand Factor/metabolism
7.
Vox Sang ; 99(3): 232-8, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20840338

ABSTRACT

BACKGROUND: Octapharma PPGmbH has recently modified its manufacturing process for solvent/detergent-treated plasma to incorporate a prion reduction step, in which a 3 log reduction has been demonstrated. The current study was undertaken to assess the impact of this procedure on haemostatic variables in the new product OctaplasLG in comparison with standard Octaplas. METHODS: Production batches of standard Octaplas (n=4) and OctaplasLG (n=16) were assessed for levels of coagulation factors, physiological protease inhibitors, markers of activation and procoagulant microparticles. Global haemostasis was assessed by a thrombin generation test (TGT) and rotational thromboelastometry (ROTEM). RESULTS: Mean levels of factors: II, V, VII, IX, X, XI, XII and XIII, VWF:Ag, antithrombin, protein C and free protein S were all >75 u/dl. ADAMTS-13 activity levels were normal. Factor VIII and VWF:RCo were >55 u/dl. TGT and ROTEM were similar in both preparations, and microparticles were present at negligible levels. Two units of OctaplasLG had slightly elevated levels of Prothrombin Fragments 1+2, but D-Dimer and thrombin-antithrombin complexes were normal in all batches. CONCLUSION: These studies indicate that the affinity chromatography procedure used in OctaplasLG does not appear to adversely affect the proven haemostatic quality of Octaplas, while offering a selective reduction in the concentration of pathological prion proteins.


Subject(s)
Blood Proteins/analysis , Hemostatics/analysis , Plasma/chemistry , Prions , Chromatography, Affinity/methods , Humans
8.
Eur Respir J ; 35(4): 742-9, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20075060

ABSTRACT

Controls for indoor air quality (IAQ) in schools are not usually performed throughout Europe. The aim of this study was to assess the effects of IAQ on respiratory health of schoolchildren living in Norway, Sweden, Denmark, France and Italy. In the cross-sectional European Union-funded HESE (Health Effects of School Environment) Study, particulate matter with a 50% cut-off aerodynamic diameter of 10 microm (PM(10)) and CO(2) levels in a day of normal activity (full classroom) were related to wheezing, dry cough at night and rhinitis in 654 children (10 yrs) and to acoustic rhinometry in 193 children. Schoolchildren exposed to PM(10) >50 microg x m( -3) and CO(2) >1,000 ppm (standards for good IAQ) were 78% and 66%, respectively. All disorders were more prevalent in children from poorly ventilated classrooms. Schoolchildren exposed to CO(2) levels >1,000 ppm showed a significantly higher risk for dry cough (OR 2.99, 95% CI 1.65-5.44) and rhinitis (OR 2.07, 95% CI 1.14-3.73). By two-level (child, classroom) hierarchical analyses, CO(2) was significantly associated with dry cough (OR 1.06, 95% CI 1.00-1.13 per 100 ppm increment) and rhinitis (OR 1.06, 95% CI 1.00-1.11). Nasal patency was significantly lower in schoolchildren exposed to PM( 10) >50 microg x m(-3) than in those exposed to lower levels. A poor IAQ is frequent in European classrooms; it is related to respiratory disturbances and affects nasal patency.


Subject(s)
Air Pollution, Indoor/statistics & numerical data , Cough/epidemiology , Rhinitis/epidemiology , Schools/statistics & numerical data , Students/statistics & numerical data , Child , Cough/diagnosis , Cross-Sectional Studies , Environmental Exposure/statistics & numerical data , Europe/epidemiology , Female , Humans , Male , Prevalence , Rhinitis/diagnosis , Rhinometry, Acoustic , Surveys and Questionnaires , Ventilation/statistics & numerical data
10.
J Thromb Haemost ; 7(7): 1114-22, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19422453

ABSTRACT

BACKGROUND: Type IIH von Willebrand disease was reported 20 years ago as a novel variant characterized by the loss of the largest multimers in plasma and platelets and absence of the typical triplet structure. OBJECTIVES AND METHODS: The propositus and his daughter have been reinvestigated and characterized at the molecular level. The identified mutations were expressed in COS-7 cells to evaluate the mechanism of this variant. RESULTS AND DISCUSSION: The propositus had normal von Willebrand factor (VWF):ristocetin cofactor activity (RCo) and high VWF antigen (VWF:Ag) values, with a low VWF:RCo/VWF:Ag ratio (0.51). No abnormalities were found in his daughter, except for the reduced triplet structure in plasma VWF and diminished ultralarge VWF (ULVWF) multimers in platelets. Three mutations were identified in the propositus: 604C>T (R202W), 4748G>A (R1583Q), and 2546G>A (C849Y). The amounts of secreted recombinant VWF (rVWF) were apparently increased for R202W (130%), R202W-R1583Q (131%), and R202W-R1583Q/WT (121%), reduced for C849Y (72%) and C849Y/WT (83%), and normal for R1583Q (107%) and R202W-R1583Q/C849Y (102%). In cell lysates, higher values were found in association with the C849Y mutation. A normal multimeric pattern was found in R1583Q rVWF, mainly dimers in R202W rVWF, and intermediate molecular weight multimers in C849Y rVWF. Hybrid R202W-R1583Q/WT and C849Y/WT rVWFs had a nearly normal multimeric pattern, whereas in hybrid R202W-R1583Q/C849Y rVWF there was a loss of large/intermediate multimers. CONCLUSIONS: The propositus phenotype seems to be due to mutations R202W and C849Y, both affecting the VWF multimerization process and, for C849Y rVWF, intracellular survival. The absent triplet multimeric structure in the propositus and its reduction in his daughter appears to be related to the lack of ULVWF multimers, which mainly contribute to the formation of satellite bands.


Subject(s)
Biopolymers/genetics , Mutation , von Willebrand Diseases/genetics , von Willebrand Factor/genetics , Animals , Biopolymers/chemistry , COS Cells , Chlorocebus aethiops , Humans , Male , Middle Aged , Phenotype , Plasmids , Polymerase Chain Reaction , von Willebrand Factor/chemistry
11.
J Thromb Haemost ; 6(9): 1534-41, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18662260

ABSTRACT

BACKGROUND: Over the last 4 years ADAMTS-13 measurement underwent dramatic progress with newer and simpler methods. AIMS: Blind evaluation of newer methods for their performance characteristics. DESIGN: The literature was searched for new methods and the authors invited to join the evaluation. Participants were provided with a set of 60 coded frozen plasmas that were prepared centrally by dilutions of one ADAMTS-13-deficient plasma (arbitrarily set at 0%) into one normal-pooled plasma (set at 100%). There were six different test plasmas ranging from 100% to 0%. Each plasma was tested 'blind' 10 times by each method and results expressed as percentage vs. the local and the common standard provided by the organizer. RESULTS: There were eight functional and three antigen assays. Linearity of observed-vs.-expected ADAMTS-13 levels assessed as r2 ranged from 0.931 to 0.998. Between-run reproducibility expressed as the (mean) CV for repeated measurements was below 10% for three methods, 10-15% for five methods and up to 20% for the remaining three. F-values (analysis of variance) calculated to assess the capacity to distinguish between ADAMTS-13 levels (the higher the F-value, the better the capacity) ranged from 3965 to 137. Between-method variability (CV) amounted to 24.8% when calculated vs. the local and to 20.5% when calculated vs. the common standard. Comparative analysis showed that functional assays employing modified von Willebrand factor peptides as substrate for ADAMTS-13 offer the best performance characteristics. CONCLUSIONS: New assays for ADAMTS-13 have the potential to make the investigation/management of patients with thrombotic microangiopathies much easier than in the past.


Subject(s)
ADAM Proteins/blood , Cooperative Behavior , von Willebrand Factor/metabolism , ADAMTS13 Protein , Humans , Hydrolysis , Reference Standards , Reproducibility of Results
12.
Haemophilia ; 14(3): 549-55, 2008 May.
Article in English | MEDLINE | ID: mdl-18328061

ABSTRACT

Missense mutations are not considered a common cause of type 3 von Willebrand's disease (VWD), the most severe defect of von Willebrand factor (VWF) characterized by undetectable levels of this protein in plasma and platelets. Nevertheless, several missense mutations have been identified in these patients. In this study, we report the cases of two Italian patients with type 3 VWD, both compound heterozygotes for different missense mutations and null alleles, p.D141Y/c.2016_2019del and p.C275S/p.W222X. We performed in vitro expression studies of the candidate missense mutations, both located in the D1 domain of VWF propeptide, to confirm their link with the disease and to understand the mechanisms of type 3 VWD responsible in these patients. Mutant and wild-type (WT) expression vectors were used for transient transfection and co-transfection studies in COS-7 cells. Single construct transfections of both missense mutations showed a strongly reduced but detectable secretion of recombinant (r)VWFs (approximately 15% of WT), with essentially only dimers being visualized on multimeric analysis. As expected, expression of a single construct of either mutation with the WT, showed mildly reduced secretion (approximately 40% of WT) and a full set of multimers. These expression studies indicate that the two amino acids D141 and C275 are key residues in the tertiary structure of the VWF propeptide. Their replacement with a tyrosine and a serine, respectively, might compromise propeptide folding, affecting both its intracellular survival and its capacity to mediate multimerization. Co-expression of hybrid rVWFs confirmed the recessive inheritance pattern of these missense mutations.


Subject(s)
Mutation, Missense , von Willebrand Diseases/genetics , von Willebrand Factor/genetics , Adult , Animals , Blood Platelets/metabolism , COS Cells , Chlorocebus aethiops , DNA Mutational Analysis , Dimerization , Female , Gene Expression , Heterozygote , Humans , In Vitro Techniques , Middle Aged , Phenotype , Polymerase Chain Reaction , Recombinant Proteins , Severity of Illness Index , Transfection , von Willebrand Diseases/blood , von Willebrand Diseases/physiopathology , von Willebrand Factor/biosynthesis
13.
J Thromb Haemost ; 5(2): 282-8, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17155947

ABSTRACT

BACKGROUND: In a patient previously diagnosed with type 2A von Willebrand disease (VWD) [absence of high and intermediate molecular weight von Willebrand factor (VWF) multimers and markedly reduced ristocetin-induced platelet aggregation (RIPA)], an infusion test of desmopressin was followed by mild thrombocytopenia. This led to further laboratory investigations of his affected brother and of family members, who showed different phenotypic patterns compatible with type 1, 2A, 2B and an uncertain classification of VWD. The two brothers were compound heterozygotes (C275R/P1337L), whereas the others members of the family were heterozygous for C275R (a novel mutation in the D1 domain) or P1337L (a type 2B mutation in the A1 domain). OBJECTIVE AND METHODS: To evaluate the role of the combined effect of the two mutations in the two brothers, C275R and P1337L recombinant (r) VWFs were transiently expressed in COS-7 cells. RESULTS: Recombinant VWF levels secreted in cell media were similar for wild-type (WT), P1337L and hybrid P1337L/WT rVWFs, reduced for hybrids C275R/P1337L and C275R/WT rVWFs, and strongly reduced for C275R rVWF. All rVWFs had a full set of multimers except C275R rVWF, which had only dimers. P1337L rVWF and C275R/P1337L rVWF showed the highest degree of binding to glycoprotein (GP) Ibalpha and the lowest to collagen, followed by P1337L/WT rVWF (with an intermediate level of binding to both ligands), and by WT rVWF with the lowest level of binding to GPIbalpha and the highest to collagen. CONCLUSION: These results suggest that the two compound heterozygous patients have a circulating VWF mainly mutated in the A1 domain (P1337L). This peculiar type 2B VWF variant showed a remarkably high affinity for the GPIbalpha platelet receptor, leading to the loss of high and intermediate molecular weight multimers and hence to decreased RIPA, as in type 2A VWD.


Subject(s)
Mutation, Missense , von Willebrand Diseases/genetics , von Willebrand Factor/genetics , Collagen/metabolism , Dimerization , Family Health , Humans , Male , Middle Aged , Pedigree , Platelet Glycoprotein GPIb-IX Complex/metabolism , Protein Binding , Recombinant Proteins/genetics , Siblings , von Willebrand Diseases/classification , von Willebrand Diseases/diagnosis
15.
J Thromb Haemost ; 4(1): 137-47, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16409463

ABSTRACT

We analyzed the association of bleeding severity with candidate gene haplotypes within pedigrees of 11 index cases of von Willebrand disease (VWD) type 2 (two type 2A, three type 2B and six type 2M), using the QTL Association model (MENDEL 5.5). In addition to the 11 index cases, these pedigrees included 47 affected and 49 unaffected relatives, as defined by VWF mutations and/or phenotype. A bleeding severity score was derived from a detailed history and adjusted for age. Donors were genotyped using a primer extension method, and eight candidate genes were selected for analysis. VWF antigen (or ristocetin cofactor activity) levels had the strongest influence on bleeding severity score. After Bonferroni correction for multiple testing, only ITGA2 promoter haplotype -52T was associated with an increased bleeding severity score (P < 0.01). This association remained statistically significant when the three type 2B pedigrees were excluded (P = 0.012) or when gender-specific bleeding categories were excluded (P < 0.01). The major haplotypes of seven other candidate genes, GP1BA, ITGA2B, ITGB3, GP6, VWF, FGB, and IL6, were not associated with bleeding severity. These results establish that genetic differences in the expression of the integrin subunit alpha2 can influence the bleeding phenotype of VWD type 2 and complement our previous findings in VWD type 1. Genetically controlled attenuation of platelet collagen receptor expression can influence risk for morbidity in clinical settings where hemostasis is compromised.


Subject(s)
Haplotypes , Hemorrhage/genetics , Severity of Illness Index , von Willebrand Diseases/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Genotype , Humans , Integrin alpha2/genetics , Male , Middle Aged , Models, Genetic , Mutation , Pedigree , Promoter Regions, Genetic , von Willebrand Diseases/blood , von Willebrand Factor/genetics
16.
J Thromb Haemost ; 3(12): 2689-94, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16246252

ABSTRACT

A novel mutation, R1308L (3923G > T) was present in the heterozygous state in five members of a family with type 2B von Willebrand disease (VWD) characterized by a full set of von Willebrand factor (VWF) multimers in plasma and by the absence of thrombocytopenia before and after desmopressin (DDAVP). The defect (R1308L) was located at the same amino acid position of one of the most common mutations associated with type 2B VWD (R1308C), which is characterized by the loss of high molecular weight VWF multimers (HMWM) in plasma and the occurrence of thrombocytopenia. To understand the mechanisms of this defect, the novel (R1308L) and 'common' (R1308C) mutations were expressed in COS-7 cells, either alone or, to mimic the patients' heterozygous state, together with wild-type VWF. R1308L recombinant VWF (rVWF) had a higher affinity for the platelet glycoprotein Ibalpha (GPIbalpha) receptor than wild-type rVWF, R1308C rVWF showing an even higher affinity. A novel finding was that both mutant rVWFs showed a similarly reduced binding to collagen type I and type III in comparison with wild-type rVWF. The latter finding suggests a more important role than recognized so far for the VWF A1 domain in VWF binding to collagen, which may contribute to the in vivo hemostatic defect associated with type 2B VWD.


Subject(s)
Collagen/metabolism , Mutation, Missense , von Willebrand Factor/genetics , Adult , Animals , COS Cells , Chlorocebus aethiops , Collagen Type I/metabolism , Collagen Type III/metabolism , Family Health , Female , Heterozygote , Humans , Italy , Membrane Glycoproteins , Membrane Proteins/metabolism , Platelet Glycoprotein GPIb-IX Complex , Protein Binding/genetics , Transduction, Genetic , von Willebrand Factor/metabolism
18.
Blood ; 98(9): 2730-5, 2001 Nov 01.
Article in English | MEDLINE | ID: mdl-11675345

ABSTRACT

Congenital or immunomediated deficiencies of the metalloprotease that cleaves physiologically von Willebrand factor (vWF) reduce or abolish the degradation of ultralarge vWF multimers that cause the formation of intravascular platelet thrombi in patients with thrombotic thrombocytopenic purpura (TTP). There is little knowledge on the behavior of the protease in other physiological and pathologic conditions. Such knowledge is important to evaluate the specificity of low protease plasma levels in the diagnosis of TTP. Using an enzyme immunoassay, the protease was measured in 177 control subjects of different ages, in 26 full-term newborns, and in 69 women during normal pregnancy. Because TTP is often associated with multiorgan involvement and acute phase reactions, clinical models of these pathologic conditions were also investigated, including decompensated liver cirrhosis (n = 42), chronic uremia (n = 63), acute inflammatory states (n = 15), and the preoperative and postoperative states (n = 24). Protease levels were lower in healthy persons older than 65 than in younger persons. They were low in newborns but became normal within 6 months, and they were lower in the last 2 trimesters of pregnancy than in the first. Protease levels were also low in patients with cirrhosis, uremia, and acute inflammation, and they fell in the postoperative period. There was an inverse relation between low protease and high plasma levels of vWF antigen and collagen-binding activity. In conclusion, low plasma levels of the vWF cleaving protease are not a specific beacon of TTP because the protease is also low in several physiological and pathologic conditions.


Subject(s)
Metalloendopeptidases/blood , Purpura, Thrombotic Thrombocytopenic/enzymology , von Willebrand Factor/metabolism , Adult , Age Factors , Aged , Biomarkers/blood , Female , Humans , Immunoenzyme Techniques , Infant, Newborn , Inflammation/enzymology , Liver Cirrhosis/enzymology , Male , Middle Aged , Pregnancy , Purpura, Thrombotic Thrombocytopenic/diagnosis , Sensitivity and Specificity , Uremia/enzymology
19.
Thromb Haemost ; 84(4): 536-40, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11057846

ABSTRACT

Type 3 von Willebrand disease is a rare autosomal disorder characterized by unmeasurable levels of von Willebrand factor and severe hemorrhagic symptoms. We studied a multiethnic group of 37 patients, from Italy (n = 14), Iran (n = 10) and India(n = 13) to identify the molecular defects and to evaluate genetic heterogeneity among these populations. Twenty-one patients (6 Italians, 9 Iranians and 6 Indians) were fully characterized at the molecular level. Twenty-four different gene alterations were identified, 20 of which have not been described previously. The majority of the mutations caused null alleles, 11 being nonsense mutations (Q218*, W222*, R365*, R373*, E644*, Q706*, S1338*, Q1346*, Y1542*, R1659*, E2129*), 4 small deletions (437delG, 2680delC, 6431delT, del 8491-8499), 3 possible splice site mutations [IVS9(-1)g-->a, IVS29(+10)c-->t, IVS40(-1)g-->c], 3 candidate missense mutations (C275S, C2174G, C2804Y), 2 small insertions (7375insC, 7921insC) and 1 large gene deletion. The latter mutation was associated with the development of alloantibodies to VWF, but this complication was also found in a patient homozygous for a nonsense mutation (Q1346*). Due to the ethnic origin of the patients most of them were the offspring of consanguineous marriages and so were homozygous for the mutations found (18/21). Our results indicate that molecular defects responsible for type 3 VWD are scattered throughout the entire VWF gene (from exon 3 to 52), and that there is no prevalent and common gene defect in the three populations studied by us.


Subject(s)
Mutation , von Willebrand Diseases/genetics , Adolescent , Adult , Alleles , Child , Female , Humans , Male , Middle Aged , Racial Groups
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