1,721,146 research outputs found
Matrix metalloproteinase and heart failure : is it time to move from research to clinical laboratories?
No full textSurfactant protein B : From biochemistry to its potential role as diagnostic and prognostic marker in heart failure
No full textGrowing interest raised on circulating biomarkers of structural alveolar–capillary unit damage and very recent data support surfactant protein type B (SP-B) as the most promising candidate in this setting. With respect to other proteins proposed as possible markers of lung damage, SP-B has some unique qualities: it is critical for the assembly of pulmonary surfactant, making its lack incompatible with life; it has no other known site of synthesis except alveolar epithelial cells different from other surfactant proteins; and, it undergoes a proteolytic processing in a pulmonary-cell-specific manner. In the recent years circulating SP-B isoforms, mature or immature, have been demonstrated to be detectable in the circulation depending on the magnitude of the damage of alveolar capillary membrane. In the present review, we summarize the recent knowledge on SP-B regulation, function and we discuss its potential role as reliable biological marker of alveolar capillary membrane (dys)function in the context of heart failure
PAI-1, the primary plasmatic inhibitor of fibrinolysis. Physiopathologic role and molecular mechanisms
No full textPlasminogen activator inhibitor 1 (PAI-1) is the primary physiological inhibitor of plasminogen activation in blood. PAI-1 is known to contribute to thrombus formation and to the development and the clinical course of acute and chronic cardiovascular diseases. Plasma levels of PAI-1 are regulated on a genetic basis but, more important, is the dependence on a series of other atherosclerotic risk factors like hypertriglyceridemia, diabetes and insulin resistance. The insulin resistance syndrome, which is characterized partly by obesity with visceral fat accumulation, is considered as a major regulator of PAI-1 expression. At least in vitro, insulin is a potent inducer of PAI-1 synthesis by human hepatic cells, and, we have recently disentangled the molecular mechanisms responsible for enhanced PAI-1 gene expression by insulin. However, clinical data fail to support a direct acute contribution of insulin in regulating circulating PAI-1 levels. Recently, it has been proposed that adipose tissue could be responsible for the elevated plasma PAI-1 level observed in insulin resistance. It now seems reasonable to view PAI-1 as one of the factors contributing to the complex gene-environment interactions involved in the formation and dissolution of thrombi
La proteomica in campo cardiovascolare: sfide ed opportunità per la cardiologia del futuro
No full textProteomics is the study of the "proteome", that is the entire protein complement of a genome. However, it is well recognized that the proteome is far more complex than previously suggested by the "one-gene, oneprotein" central dogma of biology. The proteome encompasses all proteins of a cell or organism at a given time, including not only those translated directly from genetic information but also the array of modified proteins arising from alternative splicing of transcripts and post-translational processing, resulting in modifications that have the potential to alter protein structure or biological function. As proteins are involved in virtually every cellular function, control every regulatory mechanism, and are modified in disease states, the proteome dictates the phenotype of the cell and, consequently, the tissue or organ that the cells comprise. This results in a dynamic, ongoing process of protein expression and modifications. The proteome thus consists of information from protein expression, post-translational modifications, processing and turnover, localization and time. Proteomics is aimed at identifying and characterizing these protein changes and, if applied to the field of cardiovascular sciences, it has the potential to reveal those proteins that are associated with pathogenesis and could be potentially used as predictive or prognostic markers. Cardioproteomic is still in its infancy and relatively few cardiovascular diseases have been investigated. However, it has enormously increased our knowledge of the complexity of the myocardium in terms of protein composition at cellular and organelle levels. The cardiac proteome is further complicated by protein post-translational modifications, which may regulate organelle function in physiological and pathological conditions. Therefore, the incorporation of proteomics into cardiovascular research will provide a means of exploring the mechanisms of disease onset and progression. This will in turn ultimately lead to increased efficiency of diagnosis and/or monitoring of treatment, which could dramatically increase the ability of the clinician to recognize cardiovascular disease states at a relatively early stage, and to improve the therapeutic approach
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
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