1,721,690 research outputs found
Myocardial regenerative properties of macrophage populations and stem cells
No full textThe capacity to regenerate damaged tissue and appendages is lost to some extent in higher vertebrates such as mammals, which form a scar tissue at the expenses of tissue reconstitution and functionality. Whereas this process can protect from further damage and elicit fast healing, it can lead to functional deterioration in organs such as the heart. Based on the analyses performed in the last years, stem cell therapies may not be sufficient to induce cardiac regeneration and additional approaches are required to overcome scar formation. Among these, the immune cells and their humoral response have become a key parameter in regenerative processes. In this review, we will describe the recent findings on the possible therapeutical use of progenitor and immune cells to rescue a damaged heart. © 2012 The Author(s)
Effectiveness of chitosan and other resistance inducers in the control of postharvest gray mold of strawberry
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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
Stem Cells and the Regenerating Heart
No full textThe restricted regenerative capacity of the mammalian heart remains a perplexing exception. The regenerative response launched by other injured organs involves local populations of self-renewing precursor cells, or recruitment of circulating stem cells to replace or repair the injured areas. In response to functional stress, the heart can increase its muscle mass through cellular hypertrophy, but the damaged heart needs a rapid response to repair damage to the muscle wall and maintain adequate blood flow to the rest of the body. Paradoxically, this most critical organ cannot restore the muscle loss that accompanies myocardial infarction and ischemia-reperfusion injury. Instead, interruption of the coronary blood supply results in apoptosis and fibrotic scar formation at the cost of functional muscle. As a result, the remaining cardiomyocytes undergo cellular hypertrophy, leading to decompensated function and congestive heart failure, an increasingly prevalent disease in the industrialized world
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
Stem Cells and the Regenerating Heart
No full textIn response to functional stress, the heart can increase its muscle mass through cellular hypertrophy, but a damaged heart needs a rapid response to repair damage to the muscle wall and maintain adequate blood flow to the rest of the body. In contrast to the mammalian skeletal muscle that regenerates injured tissue through activation of quiescent myogenic precursor or multipotent adult stem cell populations, the heart does not appear to retain equivalent reserve cell populations to promote myofiber repair. The relative scarcity of progenitor cells residing in the adult myocardium has prompted a search for a renewable source of circulating somatic progenitor cells that might home to the heart in response to damage. The capacity of the heart to regenerate may not be a common attribute shared by all cardiomyocytes. Although longitudinal analyses of single cultured new cardiomyocytes revealed that many cells enter into S phase in response to serum-activated pathways dependent on the phosphorylation of the Rb protein, the majority of these cells stablely arrest at either entry to mitosis or during cytokinesis. After surgical removal of the ventricular apex and rapid clotting at the site of amputation, proliferating cardiac myofibers replace the clot and regenerate missing tissue, with minimal scarring. The requirement for cell cycle reentry in this model is supported by the decreased regeneration and increased fibrosis in a temperature-sensitive mutant of a mitotic checkpoint kinase, mps. It is still formally possible that the activation of cardiac progenitor cells is largely responsible for the extraordinary capacity of the adult zebrafish to restore extensive portions of the heart
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