1,721,266 research outputs found
Fusion of bone marrow-derived stem cells with striated muscle may not be sufficient to activate muscle genes
No full textSeveral studies have demonstrated the existence of pluripotent bone marrow– derived stem cells capable of homing to injured cardiac and skeletal muscle; however, there has been little evidence demonstrating the induction
of tissue-specific endogenous genes in donor stem cells following engraftment. A new study in this issue reports an intriguing finding that raises additional concerns relating to stem cell plasticity and stem cell therapy
in an already heated and controversial field. The study demonstrates that wild-type bone marrow–derived side population stem cells are indeed readily incorporated into both skeletal and cardiac muscle when transplanted into
mice that lack δ-sarcoglycan — a model of cardiomyopathy and muscular dystrophy. However, these cells fail to express sarcoglycan and thus to repair the tissue, which suggests that this stem cell population has limited potential for cardiac and skeletal muscle regeneration (see the related article beginning
on page 1577)
Uno, nessuno e centomila: Searching for the identity of mesodermal progenitors
No full text[No abstract available
Msx-2 and Necdin in mesoangioblast and smooth muscle differentiation.
No full textThe molecular regulation of smooth muscle differentiation is currently far less well understood than that of striated muscle, in part because in this cell type, the differentiated state is plastic and reversible. In recent years, however, several molecules, the best characterized of which is myocardin, have been shown to be necessary and sufficient to promote at least partial smooth muscle differentiation. Indeed, mice deficient in myocardin have a severe reduction of smooth muscle tissue. However,
possibly because of multiple embryological origins, which include mesenchyme, neural crest, and even endothelium, different types of smooth muscle cells differ in their expression of myocardin and of other potential regulatory molecules. Here, we will review recent work on the topic, focusing on the mesoangioblast, a recently described vessel-associated stem cell, whose differentiation into smooth muscle is dependent upon expression of msx2 and necdin, but not of myocardin
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
The origin of embryonic and fetal myoblasts: a role of Pax3 and Pax7
Full text linkSkeletal muscle is a heterogeneous tissue composed of individual muscle fibers, diversified in size, shape, and contractile protein content, to fulfill the different functional needs of the vertebrate body. This heterogeneity derives from and depends at least in part on distinct classes of myogenic progenitors; i.e., embryonic and fetal myoblasts and satellite cells whose origin and lineage relationship have been elusive so far. In this issue of Genes & Development, Hutcheson and colleagues (pp. 997-1013) provide a first answer to this question. © 2009 by Cold Spring Harbor Laboratory Press
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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