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Functional analysis of the retinoic acid signaling pathway during spermatogenesis
No full textL’acide rétinoïque (AR) est requis pour de nombreuses fonctions physiologiques parmi lesquelles la reproduction. Il est synthétisé par des rétinaldéhyde déshydrogénases (RALDH1 à 3) et il active la transcription de gènes cible en se liant à ses récepteurs nucléaires RAR (α,β,γ). L’objet de mon travail de thèse a été d’étudier les fonctions de l’AR, produit dans les cellules de Sertoli testiculaire, sur la spermatogenèse de la souris. Ainsi, par l’étude de l’inactivation des gènes des RALDH spécifiquement dans les cellules de Sertoli murines grâce à la mutagenèse somatique, j’ai montré que les cellules de Sertoli dirigent la première différenciation des cellules germinales grâce à leur production d’AR qui est ensuite dispensable au bon déroulement de la spermatogenèse. L’induction de cette première spermatogenèse est possible par l’activation sélective de RAR qui est à la base d’une pléiade de voies de signalisation. J’ai également confirmé le rôle crucial de la voie de signalisation de l’AR dans les cellules de Sertoli pour la spermiation, dernière étape du processus de spermatogenèse, et donc pour la fertilité. Enfin, j’ai démontré la nécessité in vivo de la signalisation par l’AR pour la méiose, qui contrôle l’expression de Stra8, un gène essentiel pour la progression méiotique. Cette régulation se fait de manière cellulaire autonome et requiert la fixation d’un RAR sur son élément de réponse localisé dans la région promotrice de Stra8.Retinoic acid (RA) is required for many physiological functions including reproduction. It is synthesized by retinaldehyde dehydrogenases (RALDH1 to 3) and activates transcription of target genes by binding to its nuclear receptors (RAR α,β,γ ). The purpose of my thesis was to study the functions of RA produced in testicular Sertoli cells in spermatogenesis in the mouse. Thus, by studying the effects of RALDH selective inactivation in murine Sertoli cells by somatic mutagenesis, I showed that Sertoli cells direct the first differentiation of germ cells through their production of RA, which is then dispensable for the proper conduct of spermatogenesis. Induction of the first spermatogenesis is possible by selective activation of RAR, which is at the basis of several signaling pathways. I also confirmed the crucial role of the RA pathway in Sertoli cells for spermiation, the final stage of spermatogenesis, and therefore fertility. Finally, I demonstrated the need of an in vivo RA signaling for meiosis, which controls the expression of Stra8, a gene essential for meiotic progression. This regulation is done cell-autonomously and requires the binding of a RAR on its response element located in the promoter region of Stra8
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
Etude fonctionnelle de la voie de signalisation de l'acide rétinoïque au cours de la spermatogenèse
No full textL acide rétinoïque (AR) est requis pour de nombreuses fonctions physiologiques parmi lesquelles la reproduction. Il est synthétisé par des rétinaldéhyde déshydrogénases (RALDH1 à 3) et il active la transcription de gènes cible en se liant à ses récepteurs nucléaires RAR (a,b,g). L objet de mon travail de thèse a été d étudier les fonctions de l AR, produit dans les cellules de Sertoli testiculaire, sur la spermatogenèse de la souris. Ainsi, par l étude de l inactivation des gènes des RALDH spécifiquement dans les cellules de Sertoli murines grâce à la mutagenèse somatique, j ai montré que les cellules de Sertoli dirigent la première différenciation des cellules germinales grâce à leur production d AR qui est ensuite dispensable au bon déroulement de la spermatogenèse. L induction de cette première spermatogenèse est possible par l activation sélective de RAR qui est à la base d une pléiade de voies de signalisation. J ai également confirmé le rôle crucial de la voie de signalisation de l AR dans les cellules de Sertoli pour la spermiation, dernière étape du processus de spermatogenèse, et donc pour la fertilité. Enfin, j ai démontré la nécessité in vivo de la signalisation par l AR pour la méiose, qui contrôle l expression de Stra8, un gène essentiel pour la progression méiotique. Cette régulation se fait de manière cellulaire autonome et requiert la fixation d un RAR sur son élément de réponse localisé dans la région promotrice de Stra8.Retinoic acid (RA) is required for many physiological functions including reproduction. It is synthesized by retinaldehyde dehydrogenases (RALDH1 to 3) and activates transcription of target genes by binding to its nuclear receptors (RAR a,b,g ). The purpose of my thesis was to study the functions of RA produced in testicular Sertoli cells in spermatogenesis in the mouse. Thus, by studying the effects of RALDH selective inactivation in murine Sertoli cells by somatic mutagenesis, I showed that Sertoli cells direct the first differentiation of germ cells through their production of RA, which is then dispensable for the proper conduct of spermatogenesis. Induction of the first spermatogenesis is possible by selective activation of RAR , which is at the basis of several signaling pathways. I also confirmed the crucial role of the RA pathway in Sertoli cells for spermiation, the final stage of spermatogenesis, and therefore fertility. Finally, I demonstrated the need of an in vivo RA signaling for meiosis, which controls the expression of Stra8, a gene essential for meiotic progression. This regulation is done cell-autonomously and requires the binding of a RAR on its response element located in the promoter region of Stra8.STRASBOURG-Bib.electronique 063 (674829902) / SudocSudocFranceF
Retinoic acid expression associates with enhanced IL-22 production by ?? T cells and innate lymphoid cells and attenuation of intestinal inflammation.
No full textRetinoic acid (RA), a vitamin A metabolite, modulates mucosal T helper cell responses. Here we examined the role of RA in regulating IL-22 production by ?? T cells and innate lymphoid cells in intestinal inflammation. RA significantly enhanced IL-22 production by ?? T cells stimulated in vitro with IL-1? or IL-18 and IL-23. In vivo RA attenuated colon inflammation induced by dextran sodium sulfate treatment or Citrobacter rodentium infection. This was associated with a significant increase in IL-22 secretion by ?? T cells and innate lymphoid cells. In addition, RA treatment enhanced production of the IL-22-responsive antimicrobial peptides Reg3? and Reg3? in the colon. The attenuating effects of RA on colitis were reversed by treatment with an anti-IL-22 neutralizing antibody, demonstrating that RA mediates protection by enhancing IL-22 production. To define the molecular events involved, we used chromatin immunoprecipitation assays and found that RA promoted binding of RA receptor to the IL-22 promoter in ?? T cells. Our findings provide novel insights into the molecular events controlling IL-22 transcription and suggest that one key outcome of RA signaling may be to shape early intestinal immune responses by promoting IL-22 synthesis by ?? T cells and innate lymphoid cells
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
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