Notch and Hedgehog in the thymus/parathyroid common primordium:crosstalk in organ formation

The avian thymus and parathyroids (T/PT) common primordium derives from the endoderm of the third and fourth pharyngeal pouches (3/4PP). The molecular mechanisms that govern T/PT development are not fully understood. Here we study the effects of Notch and Hedgehog (Hh) signalling modulation during common primordium development using in vitro, in vivo and in ovo approaches. The impairment of Notch activity reduced Foxn1/thymus-fated and Gcm2/Pth/parathyroid-fated domains in the 3/4PP and further compromised the development of the parathyroid glands. When Hh signalling was abolished, we observed a reduction in the Gata3/Gcm2- and Lfng-expression domains at the median/anterior and median/posterior territories of the pouches, respectively. In contrast, the Foxn1 expression-domain at the dorsal tip of the pouches expanded ventrally into the Lfng-expression domain. This study offers novel evidence on the role of Notch signalling in T/PT common primordium development, in an Hh-dependent manner.</p

Stem Cells, Self-Renewal, and Lineage Commitment in the Endocrine System

The endocrine system coordinates a wide array of body functions mainly through secretion of hormones and their actions on target tissues. Over the last decades, a collective effort between developmental biologists, geneticists, and stem cell biologists has generated a wealth of knowledge related to the contribution of stem/progenitor cells to both organogenesis and self-renewal of endocrine organs. This review provides an up-to-date and comprehensive overview of the role of tissue stem cells in the development and self-renewal of endocrine organs. Pathways governing crucial steps in both development and stemness maintenance, and that are known to be frequently altered in a wide array of endocrine disorders, including cancer, are also described. Crucially, this plethora of information is being channeled into the development of potential new cell-based treatment modalities for endocrine-related illnesses, some of which have made it through clinical trials

Conception et mise en place d’un système d’information adapté aux besoins d’une entreprise en expansion

The information system is at the heart of a business and will significantly influence the performance of the organization. The economic expansion of a society requires the presence of a suitable information system that meets current requirements and will meet future needs. To implement such a system, high-impact operations will be performed, for example, the creation of domain allowing the sharing of resources or creating a backup policy. A "project" approach adapted to the risks should be chosen to ensure production throughout the period of the project. In this context, this thesis will present the implementation of an information system in a growing organization. For this purpose, we will describe the organization project we created and applied during all operations and every mission we completed in this company.Le système d'information est au cœur d'une entreprise et va participer, de façon importante, à la performance de l'organisation. L'expansion économique d'une société impose la présence d'un système d'information adapté qui répond aux exigences actuelles et qui pourra satisfaire les besoins futurs. Pour mettre en place un tel système, des opérations à forts impacts devront être réalisées comme, par exemple, la création du domaine permettant le partage des ressources, la création d'une politique de sauvegarde. Une démarche projet adaptée aux risques sera à observer afin de garantir la production durant toute la période de réalisation du projet. Dans cette optique, ce mémoire présentera l'implantation d'un système d'information au cœur d'une organisation en pleine expansion. Pour cela, nous décrirons, dans ce document, la démarche projet, le déroulement des opérations, les missions réalisées et l'atteinte des objectifs

Étude des autoévaluations des étudiants en soins infirmiers au décours d’expériences cliniques

International audienceContext: Nursing education requires implementing self-assessment procedures that actively involve students in their learning process. In this context, educational interviews implemented in nursing schools in France, provide many opportunities for teachers to probe students on their learning experiences. Aim: This qualitative and exploratory pilot study is designed to describe and examine the self-assessment content produced by nursing students following two types of interviews: elicitation interviews and conventional interviews. Method: Eleven students volunteered to take part in the self-assessment of the care they provided during clinical internships. Two self-assessments were asked from each student: one after a conventional interview and another after a elicitation interview. The 22 self-assessments were then analyzed. Results: Students are generally able to clearly and confidently assess themselves relying on a range of arguments to justify their evaluative judgment. The arguments are based on internal and external factors and vary depending on the type of interview conducted beforehand (elicitation interview or conventional interview). They show how reflective practice and self-assessment are linked. Conclusion: The evaluative judgment and the arguments used by the students in reflective practice vary in nature. The role of teachers is essential in helping students express their views. As a result teachers will be in a position to adapt their support.Contexte : La formation des infirmiers nécessite la mise en oeuvre de procédures auto évaluatives accordant à l'étudiant une implication active dans son processus d'apprentis-sage. Dans cette optique, les entretiens de suivi pédagogique mis en place dans les Institutions de formations en soins infirmiers en France donnent de multiples occasions au formateur d'entretenir l'étudiant sur son autoévaluation par rapport à ses expériences d'apprentissage. But : Cette étude pilote, qualitative et exploratoire, a pour objectif de décrire et de comprendre les contenus d'autoévaluations produits par les étudiants infirmiers suite à deux types d'entre-tiens : entretien d'explicitation (EDE) et entretien classique (EC). Méthode : Onze étudiants volontaires ont été interrogés sur leur autoévaluation concernant des soins réalisés par eux-mêmes en stage. Cette autoévaluation a été demandée à deux reprises à chacun: une fois suite à un EC, une autre fois après un EDE. Les 22 autoévaluations ont ensuite été analysées. Résultats : Les étudiants ont en général la capacité de s'autoévaluer de façon claire et affir-mée et s'appuient sur de nombreux arguments pour justifier leur jugement évaluatif. La nature de ces arguments relève de facteurs internes et externes. Elle varie en fonction du type d'entre-tien mené au préalable (EDE ou EC), signalant les liens existant entre les modalités de la réflexion sur la pratique et l'autoévaluation. Conclusion : Les jugements évaluatifs et les arguments utilisés par les étudiants lors d'une pratique réflexive sont de nature variable. Le rôle du formateur est essentiel pour aider les étudiants à les exprimer afin d'ajuster ensuite son accompagnement

The pharyngeal pouches and clefts: Development, evolution, structure and derivatives

The pharyngeal arches form the face and neck of the developing embryo. The pharyngeal tissue is divided into distinct arches by the formation of clefts and pouches in between the arches. These clefts and pouches form at the juxtaposition between the ectoderm and endoderm and develop into a variety of essential structures, such as the ear drum, and glands such as the thymus and parathyroids. How these pouches and clefts between the arches form and what structures they develop into is the subject of this review. Differences in pouch derivatives are described in different animals and the evolution of these structures are investigated. The implications of defects in pouch and cleft development on human health are also discussed. (C) 2010 Elsevier Ltd. All rights reserved

Shh signalling restricts the expression of Gcm2 and controls the position of the developing parathyroids

AbstractThe parathyroid glands originate from the endoderm of the caudal pharyngeal pouches. How these parathyroids are restricted to developing in the caudal pouches is unclear. In this paper we investigate the role of Shh signalling in patterning the vertebrate pharyngeal pouches, and show that Hh signalling may be involved in restricting the expression of the parathyroid marker Gcm2 in the pharyngeal epithelium. In the chick and mouse, Shh signalling is excluded or highly reduced in the posterior/caudal pouches, where the parathyroid marker Gcm2 is expressed, while remaining at high levels in the more anterior pouches. Moreover, though the block of Shh signalling at early developmental stages results in the loss of chick Gcm2 expression, at later stages, it induces ectopic Gcm2 expression domains in the second and first pharyngeal epithelium, suggesting that HH signalling prevents Gcm2 in those tissues. These ectopic domains go on to express other parathyroid markers but do not migrate and develop into ectopic parathyroids. Differences in the expression of Gcm2 in the chick, mouse and zebrafish, correlate with changing patterns of Shh signalling, indicating a conserved regulatory mechanism that acts to define pouch derivatives