1,720,971 research outputs found
Overactivity of exercise-sensitive cation channels and their impaired modulation by IGF-1 in mdx native muscle fibers: beneficial effect of pentoxifylline
No full textAbstract
Cell-attached patch-clamp recordings on native striated myofibers from adult dystrophic mdx mice revealed a higher occurrence and open probability compared to non-dystrophic wild-type myofibers of a 30 pS voltage-insensitive Ca2+-permeable channel, inhibited by Gd3+, streptomycin and ruthenium red. Myofibers from in vivo exercised animals had higher channel occurrence and/or open probability. Insulin-like growth factor 1 (3.3 nM) induced and/or enhanced channel activity, via PI3 kinase, in wild-type but not in mdx myofibers. Interestingly, in both genotypes the current was silenced by db-cAMP or pentoxifylline, a phosphodiesterase inhibitor. The channel activity/occurrence in pentoxifylline-treated exercised mdx (50 mg/kg/day i.p. for 4-8 weeks) overlapped that of exercised wild-type mice. Thus, a growth factor-sensitive current, likely due to a TRP channel, is activated in vivo by exercise in native striated fibers; its deregulation in the absence of dystrophin may contribute to Ca2+ homeostasis alteration. The possibility to pharmacologically counteract abnormal channel activity discloses important therapeutic application
TRP-like channels in native wt and mdx muscle fibers: differences in activity and IGF-1 responsiveness
No full text
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
Data on protein abundance alteration induced by chronic exercise in mdx mice model of Duchenne muscular dystrophy and potential modulation by apocynin and taurine
No full textHere we present original data related to the research paper entitled "Proteome analysis in dystrophic mdx mouse muscle reveals a drastic alteration of Key Metabolic and Contractile Proteins after chronic exercise and the potential modulation by anti-oxidant compounds" (Gamberi et al., 2018) [1]. The dystrophin-deficient mdx mouse is the most common animal model for Duchenne muscular dystrophy. The mdx mice phenotype of the disorder is milder than in human sufferers and it can be worsened by chronic treadmill exercise. Apocynin and taurine are two antioxidant compounds proved to be beneficial on some pathology related parameters (Schroder and Schoser, 2009) [2]. This article reports the detailed proteomic data on protein abundance alterations, in tibialis anterior muscle of mdx mice, induced by chronic exercise protocol. A selected group of mdx mice was also treated with apocynin and taurine during this protocol. Detailed MS data, comparison between mdx vs wild type, exercised mdx vs wild type, and complete analysis of spot variation are provided. Furthermore, in wild type mice subjected to the same exercise protocol, the abundance of key proteins, resulted modified in exercised mdx, were analyzed by western blot. (C) 2018 The Authors. Published by Elsevier Inc
Evaluation of potential synergistic action of a combined treatment with alpha-methyl-prednisolone and taurine on the mdx mouse model of Duchenne muscular dystrophy.
No full textAims: Glucocorticoids are the sole drugs clinically used
in Duchenne muscular dystrophy, in spite of the relevant
side effects. Combination of glucocorticoids with synergistic
drugs may be one strategy to lower doses and
control side effects, meanwhile providing wider control
of the complex pathology. This study is a preclinical
evaluation of the effect of a combined treatment of amethyl-
prednisolone (PDN) with taurine, a safe aminoacid
with positive effects on some pathology-related
events. Methods: PDN (1 mg/kg/day i.p.) and taurine
(1 g/kg/day orally) were administered either alone or in
combination, for 4–8 weeks to male dystrophic mdx mice
chronically exercised on a treadmill. Effects were assessed
in vivo and ex vivo with a variety of methodological
approaches. Results: In vivo, each treatment significantly
increased fore limb strength, a marked synergistic effect
being observed with the combination PDN + taurine. Exvivo, PDN + taurine completely restored the mechanical
threshold, an electrophysiological index of calcium
homeostasis, of extensor digitorum longus myofibres and
the benefit was greater than for PDN alone. In parallel,
the overactivity of voltage-independent cation channels
in dystrophic myofibres was reduced. No effects were
observed on plasma levels of creatine kinase, while
lactate dehydrogenase was decreased by taurine and, to a
minor extent, by PDN + taurine. A similar histology
profile was observed in PDN and PDN + taurine-treated
muscles. PDN + taurine significantly increased taurine
level in fast-twitch muscle and brain, by high-pressure
liquid chromatography analysis. Conclusions: The combination
PDN + taurine has additive actions on in vivo
and ex vivo functional end points, with less evident
advantages on histopathology and biochemical markers
of the disease
Growth hormone secretagogues induce intracellular calcium mobilization in native rat skeletal muscle fibers through ghrelin-specille receptor activation
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
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