1,720,961 research outputs found
Experimental animal models of myocardinal damage in regenerative medicine studies involving adult bone marrow derived stem cells: ethical and methodological implication
No full textCardiac performance after myocardial infarction is compromised by ventricular remodeling, which represents a major cause of late infarct-related chronic heart failure and death. In recent years, the scientists' interest has focused on the hypothesis that the administration of bone marrow progenitors, following myocardial infarction, could ameliorate left ventricular remodeling by continuing to differentiate along the haematopoietic lineage. This approach has been developed minding to the consolidated use of transfusions to restore lost or depleted blood components and, therefore, as an enriched dose of various progenitors, generally autologous, injected peripherally or directly in the infarcted area. Since the safety of this therapy was not yet established, for ethical reasons pioneering researchers involved in these studies used animal models as surrogate of the human biologic system. Herein this hypothesis of therapy resulted in an increased use of living animals and in the reappraisal of models of myocardial damage with limited discussion on the theoretical basis of animal models applied to cell-based therapies. Recently, the European Union and its commission for surveillance of laboratory animals advanced a new proposal to restrict the use of living animals. This review will focus on the history of models utilization in biomedicine, with particular attention to animal models, and delineate an operative comparison between the two best known models of myocardial injury, namely coronary ligation and cryodamage, in the perspective of adult stem cell research applied to cardiovascular regenerative medicine
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
Ki67 cytoplasmic expression: observations in normal tissue from heart atrial appendages of healthy rats
No full textDispelling 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
Limited hypotensive effect of sildenafil in a high-risk population: a preliminary report
No full textErectile dysfunction (ED) is often associated with cardiovascular disease (CVD) and the risk of sildenafil-induced orthostatic hypotension (OH) in subjects with CVD is a matter of concern. We describe our experience in using the tilt test (TT) with continuous plethysmography to evaluate the occurrence of OH in patients with CVD and ED after a test dose of sildenafil. When sildenafil was added on top of their usual pharmacological treatment two patients out of 32 (6.2%) developed asymptomatic OH, with a maximum blood pressure fall of 40/20 mm Hg. The low prevalence and modest clinical relevance of OH in our high-risk population coupled with the known high sensitivity and reproducibility of the TT seem to suggest that sildenafil is haemodynamically safer than is generally believed even when added on top of vasoactive treatment. These findings should be put into perspective against the growing wealth of evidence that PDE5 inhibitors may have therapeutic potential for a number of CV conditions
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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