1,720,990 research outputs found
Mineralocorticoid receptor activation affects skeletal muscle development and metabolism
No full textBackground: It’s known that Mineralocorticoid Receptor (MR) activation affects
adipocytes differentiation and function and we showed that MR antagonism is able
to improve insulin-stimulated glucose uptake in a mouse model of diet-induced obesity and insulin resistance. Adipose tissue secretome shows a paracrine effect on vascular system and cardiac function, as well as on skeletal muscle metabolism. Interestingly, MR blockade is able to affect skeletal muscle metabolism, improving insulin signaling. In addition, renin-angiotensin-aldosterone system (RAAS) activation, through MR-dependent mechanisms, leads to skeletal muscle athrophy in mice.
Purpose: Our aim is to evaluate a possible involvement of MR activation in regulat-
ing skeletal muscle differentiation and function in vitro and in vivo.
Methods: We investigated the involevement of MR in regulating murine skeletal
muscle cells (C2C12) differentiation and we started to characterize the impact of
adipose MR activation on skeletal muscle metabolic profile and development in a
novel adipose-specific MR knockout (MRKO) mouse model.
Results: We first characterized the ontogenensis of MR in a murine myoblast
cell line (C2C12) by RT-PCR and western blot analyses in order to evaluate
the expression of MR during myotubes differentiation in vitro. We observed an
increase in MR protein expression in skeletal myotubes during differentiation
(96h). To evaluate the effects of MR activity on C2C12 cells, we treated C2C12
myoblasts, after differentiation stimulus, with aldosterone (Aldo, 10-8 mol/L) for 6h
and 24h and we observed that Aldo significantly reduced Heavy Chain Myosin
(MHC) mRNA levels, suggesting that MR activity represses muscle cell differentiation. Such effect was also MR dependent, given that Spiro was able to revert such effect.
We also analyzed skeletal muscle insulin sensitivity in vivo in MRKO mice eval-
uating soleus muscle insulin receptor substarte-1, tyrosinephosphorylated IRS-1,
GLUT4 levels mRNA expression and Akt phosphorylation. Interestingly, we observed improved soleus muscle insulin signaling parameters and systemic insulin sensitivity in MRKO mice compared to controls. Further studies are necessary to explore the effect of MR activation on skeletal muscle development in vivo.
Conclusions: These data reveal a potential role of MR in modulating skeletal mus-
cle differentiation and insulin sensitivity, which suggest a potential application of MR
antagonists to improve skeletal muscle function
Mineralocorticoid Receptors in Metabolic Syndrome: From Physiology to Disease
No full textOver the past decade, several studies have shown that activity of extra-renal mineralocorticoid receptors (MR) regulates vascular tone, adipogenesis, adipose tissue function, and cardiomyocyte contraction. In mice, abnormal activation of MR in the vasculature and in adipose tissue favors the occurrence of several components of the metabolic syndrome (MetS), such as hypertension, obesity, and glucose intolerance. Accordingly, high levels of aldosterone are associated with obesity and MetS in humans, suggesting that altered activation of aldosterone-MR system in extra-renal tissues leads to profound metabolic dysfunctions. In this context, in addition to the classical indications for heart failure and hypertension, MR antagonists (MRAs) nowadays represent a promising approach to tackle cardiovascular and metabolic disorders occurring in the MetS
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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