73 resultados para 17E
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Brain capillary endothelial cells (BCECs) are targets of CD4-independent infection by HIV-1 and simian immunodeficiency virus (SIV) strains in vitro and in vivo. Infection of BCECs may provide a portal of entry for the virus into the central nervous system and could disrupt blood–brain barrier function, contributing to the development of AIDS dementia. We found that rhesus macaque BCECs express chemokine receptors involved in HIV and SIV entry including CCR5, CCR3, CXCR4, and STRL33, but not CCR2b, GPR1, or GPR15. Infection of BCECs by the neurovirulent strain SIV/17E-Fr was completely inhibited by aminooxypentane regulation upon activation, normal T cell expression and secretion in the presence or absence of ligands, but not by eotaxin or antibodies to CD4. We found that the envelope (env) proteins from SIV/17E-Fr and several additional SIV strains mediated cell–cell fusion and virus infection with CD4-negative, CCR5-positive cells. In contrast, fusion with cells expressing the coreceptors STRL33, GPR1, and GPR15 was CD4-dependent. These results show that CCR5 can serve as a primary receptor for SIV in BCECs and suggest a possible CD4-independent mechanism for blood–brain barrier disruption and viral entry into the central nervous system.
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Issues for 1900- called also 2e- année; 17e-20e année skipped in numbering while publication was suspended.
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Description based on: 17e année, no. 2 (mars 1929).
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Specimens are seen against sea and harbor views.
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Description based on: 8e année, no 17 (22 avril 1916); title from caption.
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Le problème de la pauvreté au Québec n'est pas un fait inhérent à notre société contemporaine. Déjà, sous le Régime français, la colonie avait dû faire face à divers malaises sociaux dont notamment la pauvreté. Pour tenter de les endiguer, les dirigeants de la colonie se servirent du modèle d'assistance français, datant du 17e siècle, sous influence féodale et ecclésiale, pour le reproduire en Nouvelle-France. Ainsi, aux 17e et 18e siècles, la responsabilité des malades et des pauvres incomba aux réseaux de solidarité que constituaient la famille et la paroisse. Durant cette période, l'action de l'Église, grâce à des institutions telles que les Hôtels-Dieu et les hôpitaux généraux et celle de l'État, par sa politique subventionnaire, ne constituèrent toutefois qu'une intervention supplétive. Cependant, les débuts de l'industrialisation au 19e siècle, l'exode rural qui s'ensuivit ainsi que l'instabilité économique et l'immigration des populations britanniques, révélèrent l'insuffisance de la structure d'aide mise en place pour secourir les pauvres et les malades. Fondées à partir de 1830, différentes associations charitables se confrontèrent, elles aussi, à des problèmes d'ordre financier. À cause de sa situation névralgique comme institution sociale, l'Église s'assura graduellement, à partir de 1840, le contrôle des associations de charité mais surtout celui de l'administration de l'assistance au Québec. Et comme le dit si bien Jean-Marie Fecteau: «la charité devient, de plus en plus, affaire de religion et de groupe ethnique. Au cours de la décennie 1840, le mouvement s'amplifie.» En 1867, l'Acte de l'Amérique du Nord britannique attribua à la province de Québec, par l'article 92, la pleine juridiction en matière de bien-être et de santé sauf ce qui concerne les hôpitaux de la marine. La reformulation du code municipal en 1871 conféra aux municipalités, mais seulement à titre discrétionnaire, la charge de l'assistance directe et celle de soutenir les institutions de charité. [...]
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Functional nucleic acids (FNA), including nucleic acids catalysts (ribozymes and DNAzymes) and ligands (aptamers), have been discovered in nature or isolated in a laboratory through a process called in vitro selection. They are nucleic acids with functions similar to protein enzymes or antibodies. They have been developed into sensors with high sensitivity and selectivity; it is realized by converting the reaction catalyzed by a DNAzyme/ribozyme or the binding event of an aptamer to a fluorescent, colorimetric or electrochemical signal. While a number of studies have been reported for in vitro sensing using DNAzymes or aptamers, there are few reports on in vivo sensing or imaging. MRI is a non-invasive imaging technique; smart MRI contrast agents were synthesized for molecular imaging purposes. However, their rational design remains a challenge due to the difficulty to predict molecular interactions. Chapter 2 focuses on rational design of smart T1-weighted MRI contrast agents with high specificity based on DNAzymes and aptamers. It was realized by changing the molecular weight of the gadolinium conjugated DNA strand with the analytes, which lead to analyte-specific water proton relaxation responses and contrast changes on an MRI image. The designs are general; the high selectivity of FNA was retained. Most FNA-based fluorescent sensors require covalent labeling of fluorophore/quencher to FNAs, which incurrs extra expenses and could interfere the function of FNAs. Chapter 3 describes a new sensor design avoiding the covalent labeling of fluorophore and quencher. The fluorescence of malachite green (MG) was regulated by the presence of adenosine. Conjugate of aptamers of MG and adenosine and a bridge strand were annealed in a solution containing MG. The MG aptamer did not bind MG because of its hybridization to the bridge strand, resulting in low fluorescence signal of MG. The hybridization was weakened in the presence of adenosine, leading to the binding of MG to its aptamer and a fluorescence increase. The sensor has comparable detection limit (20 micromolar) and specificity to its labeled derivatives. Enzymatic activity of most DNAzymes requires metal cations. The research on the metal-DNAzyme interaction is of interest and challenge to scientists because of the lack of structural information. Chapters 4 presents the research on the characterization of the interaction between a Cu2+-dependent DNAzyme and Cu2+. Electron paramagnetic resonance (EPR) and UV-Vis spectroscopy were used to probe the binding of Cu2+ to the DNAzyme; circular dichroism was used to probe the conformational change of the DNAzyme induced by Cu2+. It was proposed that the conformational change by the Cu2+ binding is important for the activity of the DNAzyme. Chapter 5 reports the dependence of the activity of 8-17 DNAzyme on the presence of both Pb2+ and other metal cations including Zn2+, Cd2+ and Mg2+. It was discovered that presence of those metal cations can be cooperative or inhibitive to 8-17 activity. It is hypothesized that the 8-17 DNAzyme had multiple binding sites for metal cations based on the results. Cisplatin is effective killing tumor cells, but with significant side effects, which can be minimized by its targeted delivery. Chapter 6 focuses on the effort to functionalize liposomes encapsulating cisplatin by an aptamer that selectively bind nucleolin, an overexpressed protein by breast cancer cells. The study proved the selective cytotoxicity to breast cancer cells of the aptamer-functionalized liposome.
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Méthodologie: Modèle interprétatif de l’archéologie phénoménologique.