1,721,068 research outputs found
Acquired von Willebrand syndrome 2004: International Registry : diagnosis and management from online to bedside
No full textThe acquired von Willebrand syndrome (AVWS) is a rare bleeding disorder with laboratory findings similar to those for congenital von Willebrand disease. Unlike the congenital farm, AVWS usually occurs in individuals with no personal or family history of bleeding. Large studies on AVWS are not available, diagnosis remains difficult and treatment empirical. Acquired von Willebrand syndrome is especially frequent in lympho- or myeloproliferative disorders. It is associated with solid tumours, immunological and cardiovascular disorders as well as other miscellaneous conditions. Diagnosis of AVWS is based on assays measuring ristocetin cofactor activity or collagen binding, which are usually abnormally low, while factor VIII coagulant activity is sometimes within the reference range. FVIII/VWF inhibiting activities are found in only a minority of cases. Bleeding episodes in patients with AVWS are mostly of the mucocutaneaus type and can be managed with desmopressin, plasma-derived factor VIII/von Willebrand factor (FVIII/VWF) concentrates and intravenous immunoglobulin. Recombinant activated factor VII can be useful in cases unresponsive to standard therapy. In conclusion, the AVWS, although rare, is certainly underestimated in clinical practice: The actual clinical impact of AVWS should be evaluated by prospective studies. The authors are co-ordinating an updated version of the International Registry on AVWS that will allow data to be entered directly online
Detailed von Willebrand factor multimer analysis in patients with von Willebrand disease in the European study, molecular and clinical markers for the diagnosis and management of type 1 von Willebrand disease (MCMDM-1VWD : reply to a rebuttal
No full textCurrent diagnostic and therapeutic approaches to patients with acquired von Willebrand syndrome : a 2013 update
No full textAcquired von Willebrand syndrome (AVWS) is an acquired bleeding disorder, first reported in 1968, with clinical and laboratory features similar to inherited von Willebrand disease. This rare bleeding disorder occurs mainly in patients with underlying lymphoproliferative, cardiovascular, myeloproliferative, and immunologic disorders. In contrast to acquired hemophilia A, AVWS is rarely associated with measurable anti-von Willebrand factor inhibitors. In most instances, AVWS is identified because of bleeding complications: in fact, more than 80% of the patients with this syndrome are active bleeders. Recurrent bleeding episodes occur in approximately 20 to 33% of patients with AVWS, especially following major trauma and surgery. Because of the heterogeneous mechanisms of AVWS, more than one therapeutic approach is often required to prevent or treat acute bleedings. Remission from some forms of AVWS can be obtained when the underlying disorders are treated
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A common 253-kb deletion involving VWF and TMEM16B in German and Italian patients with severe von Willebrand disease type 3
No full textBackground: Severe von Willebrand disease (VWD) type 3 is caused by large deletions, insertions, small truncating mutations, splice site mutations and missense mutations of the VWF gene, respectively. Large deletions have been regarded as being a rare cause of VWD type 3. Complete gene deletions have only been identified in Italian and German patients to date. However, their extent and breakpoints have not been determined yet. Objectives: To identify the breakpoints of complete VWF deletions in patients with VWD type 3. Patients/methods: Five index patients with large deletions from two unrelated German and three Italian families were investigated by polymerase chain reaction (PCR) and primer walking. Haplotypes were composed of eight deletion flanking markers. Results: After initial characterization of a homozygous 253,246 bp deletion (Δ253 k) in a German patient, with the centromeric breakpoint located between CD9 and VWF and the telomeric breakpoint in intron 3 of TMEM16B, respectively, we identified the same Δ253 k in an additional two homozygous and two compound-heterozygous patients, and in their heterozygous parents. All patients share the same deletion-associated marker haplotype. The genomic structure of the breakpoint regions favors DNA double-strand breaks followed by non-homologous end-joining repair as an underlying molecular mechanism rather than a homologous recombination event. Conclusions: Our results suggest a single genetic origin of Δ253 k. Homozygosity for Δ253 k in non-consanguineous families from two different countries may indicate a higher incidence of large deletions in VWD type 3 than previously thought. The availability of a Δ253k-specific assay allows simple and rapid detection of even heterozygous patients and carriers
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
How I treat the acquired von Willebrand syndrome
No full textThe acquired von Willebrand syndrome (AVWS) is a bleeding disorder that is frequently unrecognized or is misdiagnosed as von Willebrand disease. AVWS is characterized by structural or functional defects of von Willebrand factor (VWF) that are secondary to autoimmune, lymphoproliferative or myeloproliferative, malignant, cardiovascular, or other disorders. VWF abnormalities in these disorders can result from (1) antibody-mediated clearance or functional interference, (2) adsorption to surfaces of transformed cells or platelets, or (3) increased shear stress and subsequent proteolysis. Diagnosis can be challenging as no single test is usually sufficient to prove or exclude AVWS. Furthermore, there are no evidence-based guidelines for management. Treatments of the underlying medical condition, including chemo/radiotherapy, surgery, or immunosuppressants can result in remission of AVWS, but is not always feasible and successful. Because of the heterogeneous mechanisms of AVWS, more than one therapeutic approach is often required to treat acute bleeds and for prophylaxis during invasive procedures; the treatment options include, but are not limited to, desmopressin, VWF-containing concentrates, intravenous immunoglobulin, plasmapheresis or recombinant factor VIIa. Here, we review the management of AVWS with an overview on the currently available evidence and additional considerations for typical treatment situations
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