1,720,960 research outputs found
The Paradox of the Lupus Anticoagulant: History and Perspectives
No full textA unique coagulation inhibitor prolonging whole-blood clotting time was described
more than 50 years ago in two patients with systemic lupus erythematosus (SLE). The
immunoglobulin nature of the inhibitor and its interaction with antiphospholipid
antibodies was later demonstrated and the term “lupus anticoagulant (LA)” was
coined to describe this laboratory finding. It soon became apparent that LA was a
misnomer as it is often found in plasma from patients with clinical conditions other
than SLE and is associated with thromboembolic events that may occur in otherwise
healthy individuals. Individuals with LA have circulating autoantibodies that inhibits
blood coagulation. These are mostly of IgG or IgM class and mainly directed against a
phospholipid (PL)-binding plasma protein, β2-glycoprotein I (β2GPI). The presence of
β2GPI-dependent LA represents a well-recognized risk factor for venous and arterial
thromboembolism, as well as pregnancy loss and morbidity. β2GPI-dependent LA in
the presence of documented previous thromboembolism, or history of pregnancy
loss/morbidity, identifies definite anti-PL syndrome. Laboratory diagnosis of LA is thus
of particular importance, as it may assign patients with a common event (thrombosis)
to a group with a high risk for recurrence, which is a prerequisite for long-term oral antithrombotic treatment
Antiphospholipid syndrome and the heart: A case series and literature review
No full textAntiphospholipid syndrome is a rare autoimmune disease characterised by a high tendency of developing thrombotic events. It is diagnosed in the presence of specific laboratory criteria (positivity for lupus anticoagulant, and the presence of anticardiolipin and aβ2GPI antibodies) and clinical criteria such as thrombosis in any district (arterial or venous) and pregnancy morbidity. Being a multisystem disease, heart is commonly affected by direct (autoimmune mediated action) or indirect (thrombosis) pathological mechanisms. Heart valve lesions are the most frequent manifestations; however, the haemodynamic significance is quite uncommon but when it occurs it may require surgery that further complicates the picture due to the high risk of thrombosis. Coronary arteries and myocardium are also affected leading to ischaemic heart disease and left ventricular dysfunction. Other findings include chronic thromboembolic pulmonary hypertension and accelerated atherosclerosis. The consequences of heart involvement may be significant in overt disease. The treatment of cardiac complications is challenging and requires an in depth knowledge of the disease
Minimizing the risk of hemorrhagic stroke during anticoagulant therapy for atrial fibrillation
No full textIntroduction: Oral anticoagulation (OAC) is given for ischemic stroke
prevention in patients with nonvalvular atrial fibrillation. OAC’s most serious
complications are major bleeding and, in particular, hemorrhagic stroke.
Together with vitamin K antagonists (VKAs), direct oral anticoagulants
(DOAC) are now available which have a more rapid onset/offset of action
and more predictable anticoagulant effect. The advent of DOAC has given
to the clinician an opportunity to tailor OAC therapy in order to maximize
advantages and minimize complications.
Areas covered: This review covers data published in literature regarding the
risk of hemorrhagic stroke in patients taking OAC. Bleeding risk assessment
is discussed and different bleeding risk factors are presented. The paper will
also review clinical studies comparing DOAC against standard anticoagulation,
in regard to the risk of hemorrhagic stroke.
Expert opinion: Bleeding assessment is mandatory in order to select patients
at high hemorrhagic risk who will benefit the most from close monitoring.
Blood pressure, alcohol intake, concomitant medication and comorbidities
should be constantly evaluated and treated accordingly. During VKA therapy,
adherence and intensity of anticoagulation must be strictly monitored. DOAC
are associated with lower risk of hemorrhagic stroke than VKA. However,
periodic hepatic and renal checks as well as careful evaluation of time adherence are necessary to reduce the risk of bleeding
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
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
A Bridging Protocol in High-Thrombotic Risk Mechanical Valve Bearers Undergoing Surgery or Invasive Procedures
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