1,720,972 research outputs found
PROLIFERATIVE ACTIVITY AND ALPHA-SMOOTH MUSCLE ACTIN EXPRESSION IN CULTURED RAT AORTIC SMOOTH-MUSCLE CELLS ARE DIFFERENTLY MODULATED BY TRANSFORMING GROWTH-FACTOR-BETA-1 AND HEPARIN
No full textLocally liberated cytokines and extracellular matrix components influence the proliferation and differentiation of arterial smooth muscle cells (SMC), thus playing a role in the development of the atheromatous plaque. It has been proposed that the response of SMC to these factors is influenced by their own phenotype. We have tested the effects of transforming growth factor-beta 1 (TGF-beta 1) and heparin on proliferation and expression of alpha-smooth muscle (SM) actin, a well-established SMC differentiation marker, by cultured rat SMC obtained from the normal aorta of young or old rats and from the intimal thickening developed 15 days after endothelial denudation in young rats; these SMC are known to express different phenotypic features. Heparin and TGF-beta 1 reduced serum-induced proliferation in SMC from young and old rats. Heparin increased the expression of alpha-SM actin protein and mRNA in SMC from young and old rats, while TGF-beta 1 exerted the opposite action. Moreover, TGF-beta 1 induced the appearance of an elongated shape in SMC from both young and old rats. In SMC cultured from intimal thickening, heparin induced a reduction of cell proliferation without modifying their characteristic epithelioid shape; TGF-beta 1 increased the proliferative activity and induced an elongated cell shape as well as a ''hills and valleys'' growth pattern similar to that observed in control medial SMC; both heparin and TGF-beta 1 induced an increase of alpha-SM actin expression. Our results show that TGF-beta 1 and heparin exert different effects on the same SMC, suggesting that these substances act at least in part independently. They are also compatible with the view that the action of cytokines and of extracellular matrix components depends on the phenotype of target SMC. (C) 1994 Academic Press, Inc
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
RAT AORTIC SMOOTH-MUSCLE CELLS ISOLATED FROM DIFFERENT LAYERS AND AT DIFFERENT TIMES AFTER ENDOTHELIAL DENUDATION SHOW DISTINCT BIOLOGICAL FEATURES IN-VITRO
No full textEndothelial denudation by balloon injury of the rat aorta induces the development of a neointima as a consequence of the migration and proliferation of smooth muscle cells (SMCs). Initially, intimal SMCs show a dedifferentiated phenotype, which reverts to a normal differentiated phenotype after endothelial cells have resurfaced the vessel lumen. We investigated in vitro the proliferative and phenotypic features of SMCs from different layers of rat aorta isolated 15 and 60 days after endothelial denudation. Freshly isolated intimal cells 15 days after balloon injury (IT-15) appeared rounded and showed a decreased content of alpha-smooth muscle actin, smooth muscle myosin, and desmin compared with intimal cells isolated 60 days after balloon injury (IT-60). No morphological and cytoskeletal differences were observed among freshly isolated IT-60 cells and other medial populations, which included medial SMCs that underlie the intimal thickening. In culture, IT-15 cells showed increased proliferative activity both in monolayers and in free-floating collagen lattices. Decreased expression of alpha-smooth muscle actin and smooth muscle myosin was documented in IT-15 cells compared with IT-60 cells and other medial SMC populations in monolayer. Moreover, IT-15 cells suspended in collagen lattices were poor at contracting these collagen lattices compared with IT-60 and control SMCs. IT-60 cells were equivalent to control SMCs at lattice contraction except for a temporary delay at day 1. Cells from the media underlying the intimal thickening isolated 15 and 60 days after balloon injury proliferated less, had an increased content of alpha-smooth muscle actin, and had a greater percentage of alpha-smooth muscle actin mRNA per total actin mRNA compared with IT-60 and control SMCs. Our model appears suitable to investigate the adaptation of differently derived SMC populations to various stimuli and factors involved in SMC phenotypic modulation
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
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
High levels of cellular retinol binding protein-1 expression in leiomyosarcoma: possible implications for diagnostic evaluation
No full textRetinoid bioavailability is regulated by the activity of specific cytoplasmic receptors. High levels of cellular retinol binding protein-1 (CRBP-1) have been documented during experimental arterial and wound-healing processes, but data concerning neoplastic smooth muscle tissues are scarce and/or controversial. This study reports that the expression of CRBP-1 is markedly higher in uterine and gastrointestinal leiomyosarcomas than in leiomyomas and normal myometrium; CRBP-1 was practically absent in normal gastrointestinal smooth muscle tissue. CRBP-1 positivity was particularly elevated in the epithelioid variant of leiomyosarcoma; it was associated with increased proliferative and apoptotic rates and inversely related to smooth muscle differentiation evaluated by alpha- and gamma-smooth muscle actin and desmin expression. Western blotting and reverse-transcription polymerase chain reaction confirmed the observations concerning CRBP-1 and actin isoform expression and revealed higher NF-kappa-Bp65 and RAR alpha and lower Bax protein levels in leiomyosarcoma than in the other conditions. These findings document that a high CRBP-1 expression is associated with smooth muscle malignancy and suggest that CRBP-1 expression represents a new useful marker for the classification of unusual variants of smooth muscle tumors
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