1,720,956 research outputs found
Stress granules induced by oxidative stress in cultured fibroblast from TDP-43 mutant ALS patients
No full textStress granules (SGs) are transient cytoplasmic aggregates that rapidly form when cells are exposed to stress and consist of large messenger ribonucleoprotein (mRNPs) complexes. The SGs seem to function as storage depots for translation silenced com- plex and are implicated in stress-induced inhibition of global protein synthesis.
Protein aggregation, has been observed in several neurodegenerative diseases, including Amyotrophic Lateral Sclerosis (ALS). The protein TDP-43 (TAR DNA-Bind- ing Protein-43), encoded by one of the ALS-causative gene (TARDBP), is a major con- stituent of pathological inclusions in this disease and it is seems to be implicated in the regulation of SGs. Therefore we investigated the different characteristics of SGs in human cultured fibroblasts from ALS patients carrying TARDBPA382T mutation (group 1) versus healthy subjects (group 2). The cells were exposed to stressful conditions using sodium arsenite (SA) at different concentrations (0.5 mM, 1 mM) and exposure times (30 min, 1h). Preliminary results showed, after 30 minutes, small and sporadic cytoplasmic inclusions immunostained for TIA-1(T-cell internal antigen-1), an early marker for SGs, in both groups of cells. After 1h, the TIA-1 immunostained granules were bright, copious and scattered into the cytosol. Interestingly, we observed a sig- nificantly higher number of cells exhibiting SGs in fibroblasts from healthy controls (66%) compared to ALS patients (34%). In parallel, we identified the RNA binding protein HuR-1 (Human antigen R) in a fraction of Tia-1 positive SGs, as well as TDP- 43 localized into the nucleus of all the cells.
These data raise the possibility that TDP-43 may modulate the stress granule for- mation, contributing to the cellular response to acute stress. Moreover the TDP-43 may regulate gene expression as well as cellular recovery and survival, and conse- quently its mutation may contribute to the neurodegeneration
Reduced stress granule formation and cell death in fibroblasts with the A382T mutation of TARDBP gene: evidence for loss of TDP-43 nuclear function.
No full textTAR deoxyribonucleic acid-binding protein 43 (TDP-43) is a key protein in the pathogenesis of amyoptrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Recent studies suggest that mutations in the TDP-43 coding gene, TARDBP, as well as variations in TDP-43 protein expression levels may disrupt the dynamics of stress granules (SGs). However, it remains unclear whether the pathogenetic effect of the TDP-43 protein is exerted at the cytoplasmic level, through direct participation to SG composition, or at nuclear level, through control of proteins essential to SG assembly. To clarify this point, we investigated the dynamics of SG formation in primary skin fibroblastcultures from the patients with ALS together with the A382T mutation and the patients with ALS and healthy controls with wild-type TDP-43. Under stress conditions induced by sodium arsenite, we found that in human fibroblasts TDP-43 did not translocate to the SGs but instead contributed to the SG formation through a regulatory effect on the G3BP1 core protein. We found that the A382T mutation caused a significant reduction in the number of SGs per cell (P<0.01) as well as the percentage of cells that form SGs (P<0.00001). Following stress stimuli, a significant decrease of viability was observed for cells with the TDP-43 A382T mutation (P<0.0005). We can therefore conclude that the A382T mutation caused a reduction in the ability of cells to respond to stress through loss of TDP-43 function in SG nucleation. The pathogenetic action revealed in our study model does not seem to be mediated by changes in the localization of the TDP-43 protein
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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