1,721,067 research outputs found
Endothelium as a target for anti-phospholipid antibodies and for therapeutical intervention
No full textEndothelium activation seems to represent one of the pathogenic mechanisms that induce the trombophilic state of the anti-phospholipid syndrome. The rationale behind such a statement lies on the demonstration that: (a) the major antigen of the anti-phospholipid antibodies (beta 2 glycoprotein I) can be expressed on the endothelial cell membrane, (b) the endothelial beta 2 glycoprotein I offers suitable epitopes for circulating antibodies, (c) the binding of anti-beta 2 glycoprotein I antibodies is capable to induce the appearance of a pro-coagulant and pro-inflammatory phenotype. Both in vitro and in vivo experimental models support such a hypothesis. Although a classical vasculitic process cannot be found in the anti-phospholipid syndrome there is indirect evidence that endothelial activation/damage does occur also in vivo. The demonstration that hydroxymethylglutaryl Co-enzyme A reductase enzyme inhibitors (statins) can block endothelial cell activation induced by anti-beta 2 glycoprotein I antibodies as well as by pro-inflammatory cytokines offers new therapeutical approaches
Endothelial cell activation by antiphospholipid antibodies
No full textAntiphospholipid antibodies are mainly directed against beta 2 glycoprotein I, a phospholipid-binding protein expressed on endothelial cell membranes of different anatomical localizations and recognized by the specific autoantibodies. Antibody binding induces an endothelial activation both in in vitro and in vivo experimental models that might contribute to the prothrombotic state. Endothelial beta 2 glycoprotein I adhesion is mediated by the electrostatic interaction between its cationic phospholipid binding site and anionic structures on the cell membrane; however, binding to annexin II--the endothelial cell receptor for tissue plasminogen activator--plays also a role. Anti-beta-2 glycoprotein I antibodies up-regulate mRNA expression of pro-inflammatory mediators through NF-kappaB translocation and the signaling cascade triggered by Toll-like receptors. Because of the molecular mimicry between beta 2 glycoprotein I and viral/bacterial structures-the natural ligands for Toll-like receptors (TLR)-antibodies might cross-link the molecule associated to the receptors eventually triggering their signaling
Humoral autoimmunity against endothelium : theory or reality?
No full textDespite the discovery of anti-endothelial cell antibodies (AECA) in a heterogeneous group of disorders characterized by endothelial damage, their pathogenic role is still debated. Experimental in vitro models indicate that they can either damage endothelial cells or trigger cell signaling by reacting with as yet undefined surface molecules. However, clinical studies suggest that, in addition to AECA, other pathogenic mechanisms are involved in the vasculitic process. Recently, antibodies specific for beta 2 glycoprotein I, the phospholipid-binding protein targeted by anti-phospholipid antibodies, have been shown to display anti-endothelial activity. These autoantibodies recognize beta 2 glycoprotein I adhered to the endothelium and induce a cell perturbation that might underlie the thrombophilic state of the anti-phospholipid syndrome
Update on the pathogenesis and treatment of the antiphospholipid syndrome
No full textPurpose of review Many advancements in our understanding of the pathogenic mechanisms of the antiphospholipid syndrome (APS) have been accomplished over the recent months. Such progresses are paralleled by the development of innovative pharmacological tools that could provide novel therapeutic windows in APS management. The most recent and innovative findings about the biologic effects of antiphospholipid antibodies (aPLs) and the treatment APS will be hereby critically appraised. Recent findings Antibodies against the domain I of b2 glycoprotein I (b2GPI) are increasingly recognized as the main pathogenic subset; pioneer therapeutic options exploiting the pathogenicity of anti-domain I antibodies have been developed. AnnexinA2 and toll-like receptor (TLR)4 have been identified as the main receptors for b2GPI/anti-b2GPI antibodies on target cells; additional co-receptors might include TLR1, TLR2 and TLR6. Upon binding, aPLs engage intracellular mediators as nuclear factor kappa B and mammalian target of rapamycin, which provide potential therapeutic targets. Current innovative treatment options include novel oral anticoagulants and the complement inhibitor eculizumab. The addition to standard treatment of pleiotropic agents such as hydroxychloroquine, statins and vitamin D could allow better disease control. Summary The lively and intense research in the APS field opens new frontiers in aPL pathogenic mechanisms, as well as diagnosis and treatment of the syndrome. Video abstract http://links.lww.com/COR/A26
Innate immunity in the antiphospholipid syndrome : role of toll-like receptors in endothelial cell activation by antiphospholipid antibodies
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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
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