443 resultados para CEREBRO


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Tít. tomado de la anteport.

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Each volume contains "Biographical sketches of the authors."

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Hammerhead ribozymes are potent RNA molecules which have the potential to specifically inhibit gene expression by catalysing the trans-cleavage of mRNAs. However, they are unstable in biological fluids and cellular delivery poses a problem. Site-specific chemical modification of hammerhead ribozymes was evaluated as a means of enhancing biological stability. Chimeric, 2'-O-methylated ribozymes, containing only five unmodified ribonucleotides, were catalytically active in vitro (kcat = 1.46 min-1) and were significantly more stable in serum and lysosomal enzymes than unmodified (all-RNA) counterparts. Furthermore, they remained undegraded in cell-containing media for up to 8 hours. Stability enhancement allowed cellular uptake properties of radiolabelled ribozymes to be assessed following exogenous delivery. Studies in vulval and glial cell lines indicated that chimeric ribozymes became cell-associated via an inefficient process, which was energy and concentration dependant. A considerable proportion of ribozymes remained bound to cell-surface components, however, a small proportion (<1%) were internalised via mechanisms of adsorptive and / or receptor mediated endocytosis. Fluorescent microscopy indicated that ribozymes were localised within endosomal / lysosomal vesicles following cell entry. This was confirmed by immuno-electron microscopy, which allowed the detection of biotin-labelled ribozymes within the cell ultrastructure. Despite the predominant localisation within endocytic vesicles, a small proportion of internalised ribozymes appeared able to exit these compartments and penetrate target sites within the nucleus and cytoplasm. The ribozymes designed in this report were directed against the epidermal growth factor receptor mRNA, which is over-expressed in a malignant brain disease called glioblastoma multiforme. In order to examine the fate of ribozymes in the brain, the distribution of FITC-labelled ribozymes was examined following intra-cerebro ventricular injection to mice. FITC-ribozymes demonstrated high punctate pattern of distribution within the striatum and cortex, which appeared to represent localisation within cell bodies and dendritic processes. This suggested that delivery to glial cells in vivo may be possible. Finally, strategies were investigated to enhance the cellular delivery of ribozymes. Conjugation of ribozymes to anti~transferrin receptor antibodies improved cellular uptake 3-fold as a result of a specific interaction with transferrin receptors. Complexation with cationic liposomes also significantly improved cell association, however, some toxiclty was observed and this could be a limitation to their use. Overall, it would appear that hammerhead ribozymes can be chemically stabilised to allow direct exogenous administration in vivo. However, additional delivery strategies are probably required to improve cellular uptake, and thus, allow ribozymes to achieve their full potential as pharmaceutical agents. KEYWORDS: Catalytic

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La aplicación de las neurociencias en el conocimiento del ser humano ha demostrado cómo el empleo de estímulos sensoriales y experienciales influyen en la atención, el agrado, las emociones, el compromiso –engagement- y la memoria -recuerdo y reconocimiento- de las marcas en entornos publicitarios relacionados con la decisión de compra. El objeto a través del empleo del Neuromarketing es determinar las áreas y funciones de las activaciones cerebrales que modulan la conducta del consumidor relacionadas con la mercadotecnia y el proceso de compra en entornos comerciales. Asimismo identifica el efecto que la publicidad genera en hombres y mujeres al encontrar diferencias de género de cómo les impacta la publicidad como la utilización de personajes célebres a cada uno de ellos, con los que adecuar los mensajes a los segmentos de mercado que tiendan a la excelencia de la eficiencia publicitaria con los que ayudar a los protagonistas clave del sector de la marketing y la publicidad. A través de un estudio propio de Neuromarketing se analiza el comportamiento de hombres y mujeres durante la visualización de los anuncios publicitarios como recurso estratégico para mejorar la eficiencia publicitaria en el diseño y la comunicación de un producto, servicio o campaña publicitaria antes, durante y después del lanzamiento.La medición publicitaria realizada con algunas de las técnicas de Neuroimagen más precisas del mercado, el Electroencefalograma (EEG) y biométricas; el Ritmo Cardíaco (HR) y Respuesta Galvánica de la Piel (GSR), han registrado el aumento del nivel de atención, agrado, emociones o motivación cuando se genera una necesidad o deseo en la demanda de los consumidores mejorando las actuales técnicas de Investigación de Mercado del marketing tradicional. Estas investigaciones permiten presentar la creación del modelo de eficiencia en el diseño y comunicación publicitaria SIADEM (-SENSORY, INTENTION, ATTENTION, DESIRE, EMOTION, MEMORY-) que tiene en cuenta los elementos básicos en los que se debe basar los mensajes publicitarios de cualquier marca para atraer el interés del cerebro consumidor.