Le sentiment de compétence : modérateur du lien entre le QI et le rendement scolaire en mathématiques

La présente étude a pour but de vérifier si le QI et le sentiment de compétence interagissent lorsque l’élève doit performer à l’école et si, en l’occurrence, cette interaction est à son tour modérée par l’âge et le sexe des participants. Afin de vérifier ces hypothèses, les variables suivantes ont été étudiées chez 928 élèves de souche francocanadienne fréquentant des écoles montréalaises de niveau secondaire : la moyenne en mathématiques, le QI, le sentiment de compétence en mathématiques, l’âge, le sexe et le statut socioéconomique. Tel que prévu, le QI et le sentiment de compétence en mathématiques corrèlent de façon positive et significative avec la moyenne en mathématiques de l’élève. Les analyses montrent également une interaction significative entre le QI et le sentiment de compétence. Une fois décomposée, cette interaction indique que chez les élèves qui ont un sentiment de compétence élevé, la valeur prédictive du QI est plus élevée, alors que la relation entre le QI et la performance ne change pas de façon significative chez les élèves qui présentent un faible sentiment de compétence. Enfin, ni l’âge ni le sexe de l’élève n’influencent l’interaction entre le QI et le rendement scolaire, pas plus qu’ils ne sont corrélés avec le rendement scolaire. Les implications cliniques de cette recherche sont discutées.The purpose of the present study was to establish whether students’ self competence beliefs and IQ interact when they need to perform at school and if so, whether this interaction is moderated by age and/or sex. The mean grade in mathematics, selfcompetence beliefs in mathematics, IQ, age, sex and socioeconomic status of 928 French Canadian students from Montreal high schools were analyzed. As predicted, the students’ IQ and self‐competence beliefs in mathematics correlated in a positive and significant way with their average grade in mathematics. Analyses also confirmed a significant correlation between the IQ and students’ self‐competence beliefs. When broken down, this interaction shows that for students with high selfcompetence beliefs, the predictive value of IQ is higher, but for students with low selfcompetence beliefs, the relationship between IQ and performance does not change significantly. Finally, age and sex do not influence the interaction between the IQ and students’ self‐competence beliefs, nor are they correlated with academic performance. Clinical implications are discussed

Caractérisation par imagerie en temps réel de cultures cellulaires hépatiques en biopuces microfluidiques

Le développement de méthodes alternatives à la culture in vivo pour l évaluation de la toxicité des molécules chimiques s est accéléré ces dernières années, l objectif étant de limiter l utilisation d animaux. Préconisés par l OCDE (Organisation de coopération et de développement économiques), ces modèles alternatifs visent à mimer les conditions physiologiques en employant des systèmes in vitro ou in silico. Parmi les différents systèmes développés, les biopuces microfluidiques ont prouvé leur contribution à l amélioration des fonctions cellulaires, ce qui permet des études toxicologiques pertinentes. Les travaux de ce doctorat sont basés sur l emploi de ces biopuces pour cultiver des hépatocytes (cellules du foie) et portent sur la mise au point d une méthode d analyse d images issues de ces cultures sous microscope au cours du temps. L acquisition d images tout au long de l expérience permet de suivre, après traitement, l évolution et le comportement des cellules au contact de molécules chimiques et d évaluer les réponses toxicologiques. Les premiers résultats de ces travaux ont permis l amélioration du procédé de culture microfluidique adaptée au matériel d acquisition d images, la sélection de sondes fluorescentes, et le choix d un algorithme de traitement des images sur CellProfiler. Cela nous a permis de quantifier et caractériser certaines fonctions biologiques au sein de la biopuce comme l activité mitochondriale. Le potentiel de cet outil pour évaluer la toxicité de molécule a été testé grâce à l emploi d un toxique connu : la staurosporine. Les résultats obtenus ont révélé l impact de la mise en culture en dynamique sur le comportement des hépatocytes, et la toxicité de la staurosporine visible en biopuce.The development of alternative methods of in vivo cultures for the toxicological evaluation of chemical molecules has accelerated this last years, in order to limit the use of animals. Recommended by the OECD (Organisation for Economic Cooperation and Development), these alternative models are designed to mimic the physiological conditions using in vitro or in silico systems. Among the developed systems, microfluidic biochips have proven their contribution to the improvement of cellular functions, which allows relevant toxicological studies. This PhD thesis is based on the use of these biochips for hepatocytes culture and focus on the development of an analysis method for study these cultures under microscope over time using imaging. Image acquisition throughout the experiment enables to analyze, after image processing, the evolution and the behavior of cells in contact with chemical molecules and to evaluate toxicological responses. The first results of this work led to the optimization of the microfluidic cultures under the microscope used to get the image sequences, the selection of fluorescent probes and the development of an image processing system with CellProfiler. These works allowed the quantification and the characterization of some biological functions within the biochip such as the mitochondrial activity. Staurosporine, a well-known toxic, has been used to test the potential of this tool to evaluate the toxicity of molecules. The results showed the impact of dynamic culture on the hepatocytes behavior, and the staurosporine toxicity, in biochip cultures.COMPIEGNE-BU (601592101) / SudocSudocFranceF

Religion and Spirituality: How Clinicians in Quebec and Geneva Cope with the Issue When Faced with Patients Suffering from Chronic Psychosis

Spirituality and religion have been found to be important in the lives of many people suffering from severe mental disorders, but it has been claimed that clinicians "neglect” their patients' religious issues. In Geneva, Switzerland and Trois-Rivières, Quebec, 221 outpatients and their 57 clinicians were selected for an assessment of religion and spirituality. A majority of the patients reported that religion was an important aspect of their lives. Many clinicians were unaware of their patients' religious involvement, even if they reported feeling comfortable with the issue. Both areas displayed strikingly similar results, which supports their generalizatio

Quiescence status of glioblastoma stem-like cells involves remodelling of Ca 2+ signalling and mitochondrial shape

International audienceQuiescence is a reversible cell-cycle arrest which allows cancer stem-like cells to evade killing following therapies. Here, we show that proliferating glioblastoma stem-like cells (GSLCs) can be induced and maintained in a quiescent state by lowering the extracellular pH. Through RNAseq analysis we identified Ca 2+ signalling genes differentially expressed between proliferating and quiescent GSLCs. Using the bioluminescent Ca 2+ reporter EGFP-aequorin we observed that the changes in Ca 2+ homeostasis occurring during the switch from proliferation to quiescence are controlled through store-operated channels (SOC) since inhibition of SOC drives proliferating GSLCs to quiescence. We showed that this switch is characterized by an increased capacity of GSLCs' mitochondria to capture Ca 2+ and by a dramatic and reversible change of mitochondrial morphology from a tubular to a donut shape. Our data suggest that the remodelling of the Ca 2+ homeostasis and the reshaping of mitochondria might favours quiescent GSLCs' survival and their aggressiveness in glioblastoma. Multiform glioblastoma (GBM) is the most aggressive brain tumours with very poor prognosis. Despite a combination of surgical resection, radiotherapy and temozolomide (TMZ)-based chemotherapy, more than 90% of the patients show recurrence and the mean survival period rarely exceeds 2 years 1. According to the cancer stem cell model, the GBM lethality is due to a small sub-population of tumour cells with stem-like properties, called Glioblastoma Stem-Like Cells (GSLCs). The GSLCs have been further characterized as slow-cycling or relatively quiescent cells 2 , identified in vivo in a mouse model of glioblastoma 3 and in human glioblastoma tumors 4. These quiescent GSLCs are highly resistant to TMZ treatment 5. Quiescence is a cell-cycle arrest state which differs from the one observed in differentiation or senescence by the fact that it is reversible. Transcriptional profiling data reveals that quiescent stem cells are characterized by a common gene signature with the down-regulation of genes associated with cell-cycle progression (i.e. CCNA2, CCNB1 and CCNE2) and the upregulation of genes classified as tumour suppressors, including the cyclin-dependent kinase inhibitor p21 (CDKN1A) and the G0/G1 switch gene 2 (G0S2) 6,7. These data also show that quiescence is a G 0 phase and not a prolonged G 1 phase 8. Furthermore, quiescence is actively regulated by signals provided by the stem cell microenvironment. In glioblastoma tumours, quiescent stem-like tumour cells are found close to necrotic tissues, in specific niches characterized by an hypoxic 4,5,9 and acidic microenviron-ment 10,11. The role of the microenvironment in the control of GSLCs quiescence is still poorly understood. Considering that quiescence represents a strategy for GSLCs to evade killing, it is of utmost importance to better characterize the quiescent GSLCs and to understand what governs the transition from a proliferative to a quiescence state. Here, we performed transcriptomic analysis using RNAseq to establish the RNA signatures of proliferative and quiescent GSLCs. We showed that genes involved in Ca 2+ signalling are modulated in GSLCs and we explored the causal role of Ca 2+ during this transition. Our data points out the reversible remodelling of mitochondrial morphology from tubular to donut shape, associated with an increased capacity of mitochon-dria to capture Ca 2+ and with the modification of the kinetics of Ca 2+ influx through SOC. The remodelling o

TRPC1 AS THE MISSING LINK BETWEEN THE BMP AND Ca2+ SIGNALLING PATHWAYS DURING NEURAL SPECIFICATION IN AMPHIBIANS

International audienceIn amphibians, the inhibition of bone morphogenetic protein (BMP) in the dorsal ectoderm has been proposed to be responsible for the first step of neural specification, called neural induction. We previously demonstrated that in Xenopus laevis embryos, the BMP signalling antagonist, noggin, triggers an influx of Ca 2+ through voltage-dependent L-type Ca 2+ channels (LTCCs), mainly via Ca V 1.2, and we showed that this influx constitutes a necessary and sufficient signal for triggering the expression of neural genes. However, the mechanism linking the inhibition of BMP signalling with the activation of LTCCs remained unknown. Here, we demonstrate that the transient receptor potential canonical subfamily member 1, (Trpc1), is an intermediate between BMP receptor type II (BMPRII) and the Ca V 1.2 channel. We show that noggin induces a physical interaction between BMPRII and Trpc1 channels

Early calcium increase triggers the formation of olfactory long-term memory in honeybees

<p>Abstract</p> <p>Background</p> <p>Synaptic plasticity associated with an important wave of gene transcription and protein synthesis underlies long-term memory processes. Calcium (Ca²⁺) plays an important role in a variety of neuronal functions and indirect evidence suggests that it may be involved in synaptic plasticity and in the regulation of gene expression correlated to long-term memory formation. The aim of this study was to determine whether Ca²⁺is necessary and sufficient for inducing long-term memory formation. A suitable model to address this question is the Pavlovian appetitive conditioning of the proboscis extension reflex in the honeybee <it>Apis mellifera, </it>in which animals learn to associate an odor with a sucrose reward.</p> <p>Results</p> <p>By modulating the intracellular Ca²⁺concentration ([Ca²⁺]i) in the brain, we show that: (i) blocking [Ca²⁺]i increase during multiple-trial conditioning selectively impairs long-term memory performance; (ii) conversely, increasing [Ca²⁺]i during single-trial conditioning triggers long-term memory formation; and finally, (iii) as was the case for long-term memory produced by multiple-trial conditioning, enhancement of long-term memory performance induced by a [Ca²⁺]i increase depends on <it>de novo </it>protein synthesis.</p> <p>Conclusion</p> <p>Altogether our data suggest that during olfactory conditioning Ca²⁺is both a necessary and a sufficient signal for the formation of protein-dependent long-term memory. Ca²⁺therefore appears to act as a switch between short- and long-term storage of learned information.</p

The absence of reactive oxygen species production protects mice against bleomycin-induced pulmonary fibrosis

BACKGROUND: Reactive oxygen species and tissue remodeling regulators, such as metalloproteinases (MMPs) and their inhibitors (TIMPs), are thought to be involved in the development of pulmonary fibrosis. We investigated these factors in the fibrotic response to bleomycin of p47(phox )-/- (KO) mice, deficient for ROS production through the NADPH-oxidase pathway. METHODS: Mice are administered by intranasal instillation of 0.1 mg bleomycin. Either 24 h or 14 days after, mice were anesthetized and underwent either bronchoalveolar lavage (BAL) or lung removal. RESULTS: BAL cells from bleomycin treated WT mice showed enhanced ROS production after PMA stimulation, whereas no change was observed with BAL cells from p47(phox )-/- mice. At day 1, the bleomycin-induced acute inflammatory response (increased neutrophil count and MMP-9 activity in the BAL fluid) was strikingly greater in KO than wild-type (WT) mice, while IL-6 levels increased significantly more in the latter. Hydroxyproline assays in the lung tissue 14 days after bleomycin administration revealed the absence of collagen deposition in the lungs of the KO mice, which had significantly lower hydroxyproline levels than the WT mice. The MMP-9/TIMP-1 ratio did not change at day 1 after bleomycin administration in WT mice, but increased significantly in the KO mice. By day 14, the ratio fell significantly from baseline in both strains, but more in the WT than KO strains. CONCLUSIONS: These results suggest that NADPH-oxidase-derived ROS are essential to the development of pulmonary fibrosis. The absence of collagen deposition in KO mice seems to be associated with an elevated MMP-9/TIMP-1 ratio in the lungs. This finding highlights the importance of metalloproteinases and protease/anti-protease imbalances in pulmonary fibrosis

End-of-life care in long-term care homes : a scoping review protocol

Background: Quality end-of-life (EOL) care is essential in long-term care homes (LTCHs), as the average survival time of newly admitted residents is estimated to be around 2 to 2.5 years. However, significant challenges exist when it comes to providing EOL clinical care in LTCHs, and the available empirical evidence does not offer a clear idea of the best practices to adopt. Aim: To systematically map the state of knowledge on EOL clinical care in LTCHs, as it relates to people receiving care, family care partners, health care professionals, the characteristics of the organization, the social context, and the implementation of guides. Methods: The scoping review method by Levac et al. (2010) will be used. Data will be collected from multiple sources, including eleven databases using a combination of keywords and descriptors, references list, prospective and manual searches, and by consulting clinicians and managers from LTCHs for additional publications. The literature from 2012 and onwards will be selected if it directly concerns EOL care in LTCHs, with no restriction on the age of residents or on the type of health care professionals or family care partners. The screening and data extraction will be performed by two people independently and any discrepancies will be resolved by consensus. We will also assess the quality of publication with the critical appraisal tools developed by the Joanna Briggs Institute. We will synthesize the extracted data using content analysis and consult stakeholders in LTCHs when a first version of the data synthesis is available to enhance the interpretation of the results based on their experience. We will present results in narrative form with tables and graphs. Discussion: The results will provide evidence-based recommendations for clinical practice when available findings are conclusive and will allow identifying knowledge gaps to orient future research programs focusing specifically on EOL clinical care in LTCHs