Induction d'une stratégie visuelle de reconnaissance du genre

Le but de l’expérience décrite dans ce mémoire est d'arriver à inculquer inconsciemment aux sujets une stratégie visuelle leur permettant d'utiliser seulement une partie spécifique de l'information visuelle disponible dans le visage humain pour en reconnaître le genre. Normalement, le genre d’un visage est reconnu au moyen de certaines régions, comme la bouche et les yeux (Dupuis-Roy, Fortin, Fiset et Gosselin, 2009). La tâche accomplie par les sujets permettait un apprentissage perceptuel implicite qui se faisait par conditionnement opérant. Ces derniers étaient informés qu'un nombre de points leur serait attribué selon leur performance à la tâche. Au terme de l’entraînement, les sujets renforcés pour l’utilisation de l’oeil gauche utilisaient davantage l’oeil gauche que l’oeil droit et ceux renforcés pour l’utilisation de l’oeil droit utilisaient davantage l’oeil droit. Nous discuterons de potentielles applications cliniques de cette procédure de conditionnement.The goal of the following experiment is to make subjects unconsciously learn a visual strategy allowing them to use only part of the available visual information from the human face to correctly identify the gender of a face. Normally, the gender of a face is recognized using certain regions, like those of the mouth and the eyes (Dupuis-Roy, Fortin, Fiset et Gosselin, 2009). Our participants had to accomplish an operant conditionning task. They were informed that a number of points would be given to them according to their performance. At the end of training, the subjects that were encouraged to use the left eye indeed used the left eye more than the right. Also, those that were conditionned to use the right eye used the right eye more than the left. We will discuss the potential clinical applications of this method of conditionning

Up-regulation of caveolin expression by cytotoxic agents in drug-sensitive cancer cells

Caveolin 1 expression is down-regulated in various cancer cell lines. Interestingly, in several drug-resistant cancer cells, a strong induction of caveolin 1 expression has been reported, suggesting a role for caveolin 1 in the acquisition and/or the maintenance of the multidrug-resistance phenotype. Here, we show, in drug-sensitive lung cancer cells (A549, Calu-6 or NCI-H69), that exposure to cytotoxic drugs (taxol, doxorubicin or etoposide) is sufficient to strongly up-regulate caveolin 1 and 2 protein levels. This up-regulation is sustained even 1 week after drug removal. Our results suggest that caveolin up-regulation is an early cellular response to a cytotoxic stress taking place before drug resistance

G2/M blockade by paclitaxel induces caveolin-1 expression in A549 lung cancer cells : caveolin-1 as a marker of cytotoxicity.

Caveolins are highly expressed in terminally differentiated cells, but this expression is down-regulated in various cancer cell lines. Exposure to low doses of paclitaxel (taxol) is sufficient to up-regulate caveolin-1, suggesting that a mild cytotoxic stress induces a response implying caveolin and caveolae. Here we show that this up-regulation is sustained even after the cessation of paclitaxel treatment. After exposure to a cytostatic dose of paclitaxel (50 nM), A549 lung cancer cells are blocked in the G2/M cell cycle phase. After removal of paclitaxel, cell death occurs, accompanied with an increase in caveolin expression, suggesting an effect of caveolin in this process. Three days post-paclitaxel treatment, surviving A549 cells were passaged and only a half of them adhered to the culture dish. Adhering cells (still mainly in the G2/M cell cycle phase) were still unable to grow and progressively entered in an apoptotic state. This study suggests that effects of a low dose of paclitaxel were still present even 1 week after drug removal and that caveolin-1 is a good marker of cytotoxicity

L'impact d'une formation sur la prise de décision partagée destinée aux médecins sur l'intention des patients de s'engager dans un processus de prise de décision partagée : analyse secondaire d'un essai clinique randomisé par grappe

Cette analyse secondaire d’un essai clinique randomisé par grappe visait à évaluer l’impact d’une formation en prise de décision partagée destinée aux médecins, DECISION+2, sur l’intention des patients de s’engager dans un processus de prise de décision partagée afin de prendre la décision de recourir à un antibiotique ou non pour une infection aigüe des voies respiratoires au cours d’une visite ultérieure. Nous avons inclus 359 patients. Nous n’avons pas observé de différence statistiquement significative entre la différence de score dans l’intention de s’engager ultérieurement dans un processus de prise de décision partagée observée chez les patients du groupe DECISION+2 et ceux du groupe témoin après ajustement pour l’effet de grappe (rapport de cotes ajusté=1,55; intervalle de confiance à 95%=0,81-2,96). Des interventions ciblant directement les patients sont à considérer afin d’accroître leur intention de s’engager ultérieurement dans un processus de prise de décision partagée.We conducted a secondary analysis of the clustered randomized trial of DECISION+2, a shared decision making training program for family physicians, and assessed its impact on patients’ intention to engage in shared decision making for choosing whether or not to use antibiotics for treating an acute respiratory tract infection in a future consultation. A total of 359 patients contributed data to this secondary analysis. Overall, after adjusting for the clustered design of the trial, we saw no statistically significant difference in the change of score in intention between patients from the DECISION+2 group and those from the control group (proportional odds ratio=1.55; 95% confidence interval=0.81-2.96). Patient-directed interventions may be necessary to achieve such purpose

Aortic valve sclerosis in rabbits

BACKGROUND AND AIM OF THE STUDY: Aortic valve sclerosis is fairly common and is currently seen as a marker of systemic atherosclerosis. For unclear reasons only a minority of those sclerotic valves will evolve to become stenotic suggesting that atherogenic factors alone are insufficient to explain the development of valve stenosis. We had reported in a model of cholesterol fed rabbits that a combination of high cholesterol with vitamin D supplementation was necessary to induce valve stenosis and significant calcium deposition whereas high cholesterol alone only induced a sclerosis of the valve. In this study, we further evaluated the role of vitamin D treatment in the development of aortic valve disease (sclerosis or stenosis) in this rabbit model. METHODS: Rabbits were divided in 4 groups followed for 12 weeks: 1) no treatment; 2) cholesterol-enriched diet, 3) cholesterol-enriched diet + vitamin D2 (VD; 50000IU, daily) 4) VD alone for 12 weeks. Echocardiographic assessment of the aortic valve was done at baseline, and every 4 weeks thereafter. Aortic valve area, maximal and mean transvalvular gradients were recorded and compared over time. Immunohistological study of the valves of AS rabbits was also realized for several classical atherosclerosis markers. RESULTS: Vitamin D2 treated animal did not develop any stenosis of the valve despite increased echogenicity due to diffuse calcium deposits on the leaflets without any atherosclerotic lesions. Only the combination of high cholesterol with VD resulted in a decrease of aortic valve area. Immunohistological analysis of aortic valves from VD rabbits showed the presence of calcium deposits, T-cell infiltration in addition to positive labeling for alpha-smooth muscle cell actin. We did not observe macrophage infiltration in aortic valve leaflets of VD rabbits. CONCLUSION: Hypercholesterolemia or vitamin D supplements alone could not induce aortic valve stenosis in our animal model whereas the combination resulted in a decreased aortic valve area. These findings support the hypothesis that a combination of atherosclerotic and calcifying factors is necessary to induce aortic valve stenosis in this model

Le leadership en tant que relation leader-employé dans une adhocratie

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Le rôle adaptatif de la tristesse dans le deuil d’un parent chez l’endeuillé adulte

Le deuil normal, ou résilient, a souvent été laissé pour compte dans la littérature, au profit de l’intérêt plus grand porté au deuil pathologique. Cette réalité, qui s’inscrit dans le cadre d’une culture de médicalisation, a pu contribuer à la normalisation de la vision du deuil comme nuisible au fonctionnement et inutilement souffrant. Or, un certain regain d’intérêt pour l’étude des processus du deuil normal est visible dans la littérature, l’idée que le deuil résilient est en fait plus répandu que les deuils plus difficiles n’ayant été que récemment démontrée empiriquement (Bonanno, 2009). Une confusion demeure quant au rôle des émotions liées au deuil, qui sont souvent vues comme des symptômes, étant mal différenciées les unes des autres dans leur nature et leur fonction. Pourtant, la tristesse, apanage d’un deuil résilient et sain, aurait une fonction adaptative, contrairement à la détresse et la dépression, qui évoquent davantage le processus de séparation entre l’enfant et sa figure d’attachement. En effet, l’enfant, lors du départ de la figure d’attachement, vit une émotion débordante et intolérable, la protestation, suivie d’un état de désespoir. Ces émotions seraient ainsi qualitativement différentes, et non seulement quantitativement différentes. Cette thèse vise donc d’une part, via un volet théorique, à proposer un modèle du deuil résilient, mais aussi du deuil pathologique, en lien avec la tristesse, la détresse et la dépression, redonnant à chacune leur juste place. Ces deux types de deuil sont présentés comme les extrêmes d’un continuum entre lesquels toute variation peut exister. La tristesse, dans ce modèle, est dépeinte comme une émotion utile, jouant un rôle dans l’acceptation de la perte et dans la capacité à lui donner un sens. D’autre part, un volet empirique s’intéresse à l’expérience subjective de la tristesse chez des endeuillés résilients adultes ayant perdu un parent. Des entrevues semi-structurées ont été conduites auprès de six participants, et les résultats ont été analysés avec une approche qualitative, l’Analyse Phénoménologique Interprétative (IPA). Les résultats montrent que la tristesse était vécue comme étant tolérable, comme ayant une fonction adaptative et un sens, même si elle reste désagréable à vivre. Comme le deuil n’est pas vécu en vase clos, un surplus de matériel à métaboliser et des circonstances externes variables, ainsi que des variations dans les capacités de mentalisation, peuvent expliquer la présence d’autres expériences émotionnelles et de symptômes somatiques. La tristesse semble toutefois être un ingrédient essentiel d’un deuil résilient, où la personne demeure fonctionnelle et n’est triste que par courtes périodes, venant par vagues. Les implications cliniques et diagnostiques de ces résultats ainsi que du modèle présenté dans cette thèse sont abordées.Normal, or resilient, grief has often been neglected in the literature, overshadowed by the greater number of studies on pathological grief. This fact, congruent with the trend towards a culture of medicalization, can explain the normalization of the idea of grief as uselessly painful, or even harmful, a nuisance to productivity and functioning. On the other hand, there has been a growing interest in the processes of normal grief in recent years, the idea that resilient grief is more common than pathological grief having only been recently supported by empirical research (Bonanno, 2009). However, the function and nature of grief-related emotions, which are often seen as symptoms, still isn’t clear. Sadness, contrarily to common knowledge, seems to be a healthy characteristic of resilient grief, and could have an adaptive function, whereas distress and depression would evoke the protest and despair phases of the separation between the child and her attachment figure. Thus, these three affective experiences would be qualitatively, and not only quantitatively, distinct. This thesis aims to present, in its first part, a theoretical model of both resilient and pathological grief, elaborating on the function and place of sadness, distress and depression. These two types of grief are presented as the extremes of a continuum, in between which any number of variations could exist. Sadness, in this model, is depicted as a useful emotion that plays a part in the acceptation of loss and in the creation of a meaning. In its second, empirical part, the subjective experience of sadness in resilient grieving adults who lost a parent is observed. Semi-structured interviews were conducted with six participants, and the results were analyzed using Interpretative Phenomenological Analysis (IPA). Results show that sadness was experienced as tolerable, adaptive, and making sense, even if it was painful. As grief is never an isolated experience in life, circumstances and concurrent events, and variations in mentalization abilities, can explain the presence of other emotions or of somatic symptoms. Sadness, however, seems to be an essential ingredient of resilient grief, where the person remains functional, but is sad only by shorts bursts, coming in waves. The clinical and diagnostic implications of these results and of the theoretical model presented in this thesis are discussed

Colloque international « Le Film Français 1945-1958 : penser les évolutions d’une revue corporative »

« La Bible du cinéma », « la voix de la profession », ce sont quelques-unes des dénominations courantes de la revue corporative le Film français, qui se présenta comme « Le journal officiel du cinéma français » dans son premier numéro sorti au lendemain de la Libération, le 8 décembre 1944. Source incontournable pour tout chercheur qui se penche sur le cinéma en France, ce périodique, qui fête cette année ses soixante-dix ans, n’a cependant pas donné lieu jusqu’ici, à notre connaissance, à de..

Carvedilol treatment for aortic valve regurgitation

Background — Aortic regurgitation (AR) is a chronic disease for which there is currently no approved medical treatment. We previously reported in an animal model that β-blockade with metoprolol exerted beneficial effects on left ventricular remodeling and survival. Despite the recent publication of promising human data, β-blockade in chronic AR remains controversial. More data are needed to support this potentially new treatment strategy. We hypothesized that carvedilol might be another safe treatment option in chronic AR, considering its combined β-blocking and α-blocking effects and proven efficacy in patients with established heart failure. Methods and Results — The effects of a 6-month treatment with carvedilol 30 mg/kg/d orally were evaluated in adult Wistar rats with severe AR. Sham-operated and untreated AR animals were used as controls. Carvedilol treatment resulted in less left ventricular hypertrophy and dilatation. Ejection fraction was improved and filling pressures were reduced by carvedilol. β1-Receptor expression was also improved as well as myocardial capillary density. Those beneficial effects were noted despite the presence of drug-induced bradycardia. Conclusions — Carvedilol exerted protective effects against volume-overload cardiomyopathy in this model of aortic valve regurgitation with preserved ejection fraction. These results suggest a protective class effect of β-blockers. Combined with the recent publication of promising human data, our findings support the need to carefully design a prospective study in humans to evaluate the effects of β-blockers in chronic aortic valve regurgitation

Spironolactone treatment for aortic valve regurgitation

BACKGROUND AND AIM OF THE STUDY : Aortic regurgitation (AR) is a disease for which there is currently no effective medical treatment. It has been shown previously in an experimental model of AR that the renin-angiotensin-aldosterone system (RAAS) plays a major role, and that medications blocking the RAAS are effective to protect against left ventricular (LV) hypertrophy and also help to maintain a normal systolic function. The role of aldosterone receptor blockers in this disease has never been evaluated. Thus, the effects were studied of the aldosterone receptor blocking agent spironolactone in a model of chronic AR in rats. METHODS : The effects of a six-month treatment with spironolactone were evaluated in adult Wistar rats with severe AR, compared to sham-operated and untreated AR animals. RESULTS : Spironolactone treatment decreased the total heart weight. In addition, the LV expression of atrial natriuretic peptide mRNA was decreased by spironolactone treatment, as was the expression of collagen 1 and LOX1 mRNAs. Left ventricular fibrosis was decreased by spironolactone treatment. CONCLUSION : Spironolactone protected against volume-overload cardiomyopathy in this model of aortic valve regurgitation. The predominant protective effect was a decrease in myocardial fibrosis