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The effective diagnosis of leukemia subtypes requires the detection of multiple cell surface markers. Current methods of detection use mostly fluorophores, which are limited by their large spectral bandwidths, photobleaching, and incompatibility with histological stains used for morphological assessments. Antibody-conjugated Surface enhanced Raman scattering (SERS) nanoparticles is an alternative tool that overcomes these limitations. A current drawback of SERS is the lack of available tools to analyze the bioconjugation of antibodies to nanoparticles following EDC/sulfo-NHS cross-linking, which produces inconsistent results and determines the efficacy of SERS probe targeting. This study uses the flow cytometry approach to evaluate SERS particles by incorporating FITC and DyLight650 secondary antibodies. Flow cytometry was also used to assess targeting of particles to markers on LY10 cells and CLL cells and to detect SERS signals by inserting a 710 BP 10nm FWHM filter specific for MGITC.

The effective diagnosis of leukemia subtypes requires the detection of multiple cell surface markers. Current methods of detection use mostly fluorophores, which are limited by their large spectral bandwidths, photobleaching, and incompatibility with histological stains used for morphological assessments. Antibody-conjugated Surface enhanced Raman scattering (SERS) nanoparticles is an alternative tool that overcomes these limitations. A current drawback of SERS is the lack of available tools to analyze the bioconjugation of antibodies to nanoparticles following EDC/sulfo-NHS cross-linking, which produces inconsistent results and determines the efficacy of SERS probe targeting. This study uses the flow cytometry approach to evaluate SERS particles by incorporating FITC and DyLight650 secondary antibodies. Flow cytometry was also used to assess targeting of particles to markers on LY10 cells and CLL cells and to detect SERS signals by inserting a 710 BP 10nm FWHM filter specific for MGITC.

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

L’athérosclérose est une maladie inflammatoire, caractérisée par une accumulation lipidique et cellulaire, dont le macrophage est l’acteur principal. Dans l’athérosclérose, le macrophage sécrète des cytokines qui favorisent le chimiotactisme et donc la migration et l’internalisation des cellules immunitaires, accentuant le processus pro-inflammatoire et accélérant l’évolution des plaques athéromateuses et leur instabilité jusqu’à éventuellement la rupture et/ou la formation de thrombus. Il est donc important de développer une technique d’imagerie cellulaire permettant de visualiser les macrophages et leur migration dans divers contextes pathologiques pour mieux comprendre leur implication, permettre le suivi thérapeutique et probablement leur utilisation dans la thérapie vectorisée. Le but de ce travail vise principalement à marquer aux nanoparticules de fer des macrophages activés de manière classiques (macrophages dits « M1 ») pour l’évaluation du statut inflammatoire dans un premier temps au sein des plaques d’athérome, et la visualisation de la dynamique de leur recrutement par IRM. Dans un deuxième temps, la méthode est exploitée pour montrer in vivo l’effet d’un traitement permettant de diminuer l’inflammation dans la plaque chez des souris invalidées pour le gène de l’apolipoprotéine E (ApoE-/-). Enfin, l’utilisation du protocole de marquage des macrophages M1 et leur suivi par IRM sont appliqués au diagnostic par imagerie d’une inflammation transitoire et circonscrite au poumon, induite par les lipopolysaccharides (LPS). En conclusion, le marquage des monocytes dirigés vers la voie M1 pour leur détection par IRM représente une méthode solide pour étudier différents phénomènes immunologiques en particulier le processus inflammatoire, et peut être un outil ou une approche de vectorisation permettant le suivi thérapeutique, cellulaire ou génique / Atherosclerosis is an inflammatory disease characterized by vessel wall lipids and cells accumulation, for which the macrophage acts as a central actor. In atherosclerosis the macrophage secretes cytokines that promote chemotaxis and thus migration and internalization of immune cells. This phenomenon emphasizes pro-inflammatory processes and accelerates the development of atherosclerotic plaque unstability to potentially its rupture with or without thrombus formation. It is therefore important to develop a technique for cell imaging to visualize macrophages and their migration in various pathological contexts to better understand their involvement, to allow therapeutic drug monitoring and probably their use in vectorized therapy. The aim of this work is mainly to label activated macrophages in classical way (macrophages called "M1") by iron nanoparticles, first to evaluate the inflammatory status within atherosclerotic plaques, and visualize their dynamic recruitment by MRI. In a second step, the method is used to show in vivo the effect of a treatment to reduce inflammation in the plaque, in mice invalidated for the gene for apolipoprotein E (ApoE-/ -). Finally, the protocol for M1 macrophages labelling and MRI tracking, was used for diagnostic imaging of a transient inflammation confined to the lung induced by lipopolysaccharide (LPS). In conclusion, the labelling of monocytes headed towards M1 polarization for their detection by MRI is a robust method to study various immunological phenomena in particular the inflammatory process, and can be an approach to vectorization and monitoring for gene or cell therapy

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

Otic neuronal precursors are specified in the otic placode but interestingly do so only in the anterior domain of the otic placode, the proneural domain. In the present study, we have explored why only this territory has the competence to undergo neurogenesis, this means the early events of otic proneural regionalization and neural commitment. The proneural and non-neural domains presented complementary gene expression patterns of transcription factors and members of the Notch pathway. Overall, we propose that proneural character is acquired in the anterior territory by the action of localized ectodermal FGF8-FGF10 signaling that enhances Sox3 function. FGF signals through Sox3 activity would be essential for the specification of the proneural domain versus a non-neural territory, while Notch would be involved in refining this early regionalization. / Els precursors neurals de la oïda són especificats dins un subdomini de la placoda acústica, el domini proneural. En aquesta tesis doctoral, s'ha explorat la raó per la qual la competència neural només és adquirida en aquest subdomini. Els dominis neural i no-neural del territori presenten dominis d'expressió genètica complementaris. Aquest treball proposa que el caràcter proneural és adquirit en el subdomini anterior del territori per l'acció de FGF8 i FGF10 localitzats en l�ectoderm �tic que promouen l�acci� de Sox3. De manera que, les senyals FGF i l�activitat Sox3 s�n essencials per l�especificaci� del domini proneural, mentre que la via Notch �s necess�ria per refinar la regionalitzaci� final entre un domini neural complementari a un domini no-neural.