1,720,974 research outputs found
Identification of non-coding RNAs involved in dystrophinopathies
No full textLes dystrophies musculaires de Duchenne (DMD) et de Becker (BMD) sont dues à des mutations dans le gène DMD codant la Dystrophine. De nombreux aspects des mécanismes pathophysiologiques de ces maladies ne sont pas encore expliqués. Nous nous sommes intéressés à l'étude d'ARN non-codants pouvant participer à ces processus. Une première étude a été centrée sur l’identification de micro-ARNs (miARNs) impliqués dans la régulation de l’oxyde nitrique synthase neuronale (nNOS) une protéine partenaire de la Dystrophine et associée à des caractéristiques de ces pathologies telles que la fatigabilité musculaire. 617 miARNs ont été criblés par Taqman Low Density Array dans des muscles de sujets sains et de patients BMDdel45-55. 4 miARNs candidats ont été sélectionnés de cette étude pour leur surexpression chez les patients BMDdel45-55 et leur capacité théorique à cibler nNOS. Des expériences de modulation de l’expression de ces miARNs dans des myoblastes humains sains ou dystrophiques nous ont permis d’identifier que le miR-708-5p et le miR-34-5p pouvaient cibler nNOS et moduler son expression.Un deuxième axe a été mené sur l’étude des longs ARNs non-codants (lncARNs). Les introns 44 et 55, qui bornent les exons 45 à 55 délétés chez les patients BMDdel45-55, sont de grandes régions contenant des lncARNs décrits comme régulant la Dystrophine. Les points de cassure introniques des mutations de ces patients n’étant pas décrites, nous avons supposé l’existence de profils de lncARNs différents. L’analyse de l’ADN de ces patients montre en effet des profils de lncARNs différents, révélant ainsi l’importance d’une étude plus précise des zones de délétion des patients BMDdel45-55.Duchenne (DMD) and Becker (BMD) muscular dystrophies are due to mutations in DMD gene, encoding Dystrophin. Many aspects of pathophysiological mechanisms of these diseases are not yet well understood. We were interested in the study of non-coding RNAs that could be involved in these pathological processes. A first study focused on micro-RNAs (miRNAs) that could modulate expression of the neuronal nitric oxide synthase (nNOS), a partner of Dystrophin which is linked to pathological features as muscular fatigability. 617 miRNAs were screened by Taqman Low Density Array in muscle biopsies of healthy subjects or BMDdel45-55 patients. 4 candidate miRNAs were selected from this study since they were overexpressed in BMDdel45-55 patients and for their theoretical ability to target nNOS. Experiments modulating the expression of these miRNAs in healthy or dystrophic human myoblasts enabled us to identify that miR-708-5p and miR-34-5p could target nNOS and modulate its expression.A second axis was conducted on long non-coding RNA (lncRNA). Introns 44 and 55, which bound exons 45-55 deleted in BMDdel45-55 patients, are large regions containing lncRNAs described as regulating Dystrophin. Since intronic breakpoints of DMD mutations of these pateints were not described, we have assumed the existence of different profiles of lncRNAs. DNA analysis of these patients actually showed different lncRNAs profiles, thus revealing the significance of a more precise analysis of deletion areas in DMD gene of BMDdel45-55 patients
The CaVβ1 isoforms : role in neuromuscular junction formation and implication in Myotonic Dystrophy type 1 pathophysiology
No full textQuatre protéines CaVβ (CaVβ1 à CaVβ4) sont connues comme des sous-unités régulatrices des canaux Ca2+ dépendants du voltage (Voltage-gated Ca2+ Channels, VGCC), chacune ayant des profils d'expression spécifiques selon leur fonction. Bien qu'elles soient principalement reconnues pour leur rôle dans la régulation des VGCC, les protéines CaVβ peuvent également agir indépendamment de ces canaux, en tant que régulateurs de l'expression génique. Parmi ces protéines, CaVβ1 est exprimée dans le muscle squelettique sous différentes isoformes. L'isoforme adulte constitutive, CaVβ1D, est localisée au niveau du sarcolemme et plus précisément à la triade, où elle joue un rôle crucial dans la régulation de CaV1 et ainsi du mécanisme de Couplage Excitation-Contraction (CEC), essentiel à la contraction musculaire. Dans cette thèse, nous nous sommes concentrés sur les isoformes embryonnaires/périnatales de CaVβ1, moins étudiées, y compris la CaVβ1E précédemment décrite. Nous avons étudié leurs rôles dans les systèmes neuromusculaire et musculaire. En effet, la protéine CaVβ1 s'est révélée essentielle au développement correct de la Jonction NeuroMusculaire (JNM), mais l'implication spécifique de ses isoformes y reste inconnue. Notre étude a donc évalué le rôle des isoformes CaVβ1 à différents stades de la formation et de la maturation/maintien de la JNM. Parallèlement, étant donné la dérégulation de CaVβ1 dans la dystrophie myotonique de type 1 (DM1), nous avons exploré son rôle fonctionnel dans ce contexte pathologique. Nous avons tout d'abord identifié CaVβ1A comme une isoforme exprimée pendant l'embryogenèse et les stades périnataux. Nos résultats ont révélé que l'expression des isoformes CaVβ1 est régulée par l'activation différentielle des promoteurs au cours du développement : un promoteur1 dans l'exon 1 contrôle l'expression de CaVβ1A/E, tandis qu'un promoteur2 dans l'exon 2B contrôle l'expression de CaVβ1D. Il est intéressant de noter qu'un endommagement du nerf déclenche une réactivation du promoteur1, conduisant à la réexpression des transcrits de CaVβ1A/E.De plus, nous avons découvert que les isoformes embryonnaires/périnatales de CaVβ1 sont essentielles pour la pré-empreinte in vitro des myotubes et que leur expression postnatale influence la maturation/maintien de la JNM. Dans le contexte pathologique de la DM1, nous avons observé une augmentation de l'expression de CaVβ1A/E, qui semble atténuer la myotonie, un symptôme caractéristique de cette pathologie. De plus, nous avons trouvé que la modulation de leur expression est liée aux protéines MBNL, centrales dans la physiopathologie de la DM1. En conclusion, ce travail de thèse a permis de clarifier les connaissances sur les différentes isoformes de CaVβ1 dans le muscle squelettique et d'apporter de nouveaux éléments sur leur rôle dans deux contextes indépendants : le développement de la JNM et de la physiopathologie de la DM1. Comprendre la régulation des isoformes protéiques de CaVβ1 dans le muscle squelettique est essentiel pour déchiffrer les mécanismes de l'homéostasie musculaire et potentiellement identifier de nouvelles approches thérapeutiques pour faire face aux pathologies musculaires.Four CaVβ proteins (CaVβ1 to CaVβ4) are described as regulatory subunit of Voltage-gated Ca2+ channel (VGCC), each exhibiting specific expression pattern in excitable cells based on their function. While primarily recognized for their role in VGCC regulation, CaVβ proteins also function independently of channels, acting as regulators of gene expression. Among these, CaVβ1 is expressed in skeletal muscle as different isoforms. The adult constitutive isoform, CaVβ1D, is located at the sarcolemma and more specifically at the triad, where it plays a crucial role in regulating CaV1 to control Excitation-Contraction Coupling (ECC) mechanism, essential for muscle contraction.In this thesis, we further explored the less studied CaVβ1 isoforms, with a particular focus on embryonic/perinatal variants, including the previously described CaVβ1E. We investigated their roles in the neuromuscular and muscular systems. Indeed, CaVβ1 proteins have been showed as essential for NeuroMuscular Junction (NMJ) development, though the involvement of specific isoform remains unclear. Our investigation assessed the role of CaVβ1 isoforms at different stages of NMJ formation and maturation/maintenance. Additionally, given the deregulation of CaVβ1 in Myotonic Dystrophy Type 1 (DM1), we explored its functional role in this muscular pathological context.First, we identified CaVβ1A as another isoform expressed during embryogenesis and perinatal stages. Our findings revealed that CaVβ1 isoforms expressions are regulated by the differential activation of promoters during development: a promoter1 in exon 1 drives CaVβ1A/E expressions, while a promoter2 in exon 2B controls CaVβ1D expression. Interestingly, nerve damage in adult muscle triggers a shift toward the promoter1 activation and leading to the re-expression of CaVβ1A/E transcripts. Furthermore, we found that CaVβ1 embryonic/perinatal isoforms are critical for proper in vitro pre-patterning of myotubes and that their postnatal expressions influences NMJ maturation/maintenance. In the pathological context of DM1, we observed the increased expression of CaVβ1A/E, which appears to mitigate myotonia symptoms. In addition, we found that the modulation of their expression is linked with MBNL proteins, which are central in the pathophysiology of DM1. In conclusion, this thesis work has clarified knowledge of the various CaVβ1 isoforms in skeletal muscle and provides new insights into their role in two independent contexts of NMJ development and DM1 pathophysiology. Understanding CaVβ1 protein regulation in skeletal muscle is essential to decipher muscle homeostasis mechanisms and potentially identify new therapeutic targets to face muscular disorders
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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