926 research outputs found

    REPRESSION OF MYC-RAS COTRANSFORMATION BY MAD IS MEDIATED BY MULTIPLE PROTEIN-PROTEIN INTERACTIONS

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    Mad is a bHLH/Zip protein that, as a heterodimer with Max, can repress Myc-induced transcriptional transactivation, Expression of Mad is induced upon terminal differentiation of several cell types, where it has been postulated to down-regulate Myc-induced genes that drive cell proliferation. Here we show that Mad also blocks transformation of primary rat embryo fibroblasts by c-Myc and the activated c-Ha-Ras oncoproteins. Mad mutants lacking either the basic region, the leucine zipper, or an intact NH2-terminal protein interaction domain fail to inhibit Myc-Ras cotransformation. These results indicate that the repression of cotransformation requires DNA-binding and is mediated by multiple protein-protein interactions involving both Max and mSin3, a putative mammalian corepressor protein. With increasing amounts of the cotransfected myc gene, the numbers of transformed foci are reduced and the ability of Mad to inhibit focus formation is attenuated. Moreover, cell lines derived from such foci constitutively express both Myc and Mad proteins. Whereas Bcl-2 can significantly increase the numbers of transformed foci by enhancing the survival of myc-ras-transfected cells, it does not counteract the repressive effects of Mad on transformation, suggesting that Mad affects the growth properties rather than the viability of cells. Taken together, our results demonstrate that Mad is capable of antagonizing the biological effects of Myc and thereby suggest that Mad could function as a tumor suppressor gene

    Editorial

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    Bioethics and medical ethics

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    A expressão ética médica pode ser definida como aquilo que os médicos tomaram por hábito denominar “o cumprimento ao determinado pelo código de ética: deveres e direitos dos médicos”. A bioética afirma-se como uma área do conhecimento humano que relaciona os valores éticos com fatos biológicos sobretudo aqueles fatos que envolvem a vida e a saúde do seres humanos dentro de um meio ambiente adequado.The expression medical ethics may be defined as what physicians usually say “to follow what is determined by the ethics code”: duties and rights of physicians”. Bioethics is an area of human knowledge which relates ethic values with biological facts mainly those facts which involve life and health of human beings within a proper environment

    Ethical aspects of brain death and end-of-life

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    Abstract -Ethical issues surrounding brain death and end-of-life have not been afforded in Brazil the same attention as in many developed countries. There appears to be reluctance on the part of Brazilian doctors to limit or suspend procedures or treatment which prolongs life of patients in terminal phases of severe incurable illness, or to suspend the artifi cial means of supporting vegetative functions in cases of brain death outside the context of organ and tissue donation for transplant. Fears grounded in possible administrative (Regional Medical Councils) or legal repercussions, as well as ambiguous interpretations of religious precepts, partially explain this reluctance which often results in unnecessary prolonging of patient suffering. A recent resolution by the Federal Medical Council on end-of-life may offer doctors some guidance and confi dence in dealing with highly complex ethical situations. Key words: brain death, end-of-life, ethics. Aspectos éticos da morte encefálica e terminalidade da vida Resumo -Questões éticas relativas à morte encefálica e terminalidade da vida não têm ainda no Brasil o mesmo destaque que em países desenvolvidos. Os médicos brasileiros parecem ter resistência em limitar ou suspender tratamentos ou procedimentos de prolongamento da vida em pacientes em fase terminal de doença grave e incurável, ou em suspender os meios artifi ciais da manutenção de funções vegetativas em casos de morte encefálica fora do contexto de doação de órgãos e tecidos para transplante. Receio quanto a possíveis sanções administrativas (Conselhos Regionais de Medicina) ou legais, além de duvidosas interpretações de preceitos religiosos explicam, ao menos parcialmente, essa relutância, que freqüentemente resulta em prolongamento desnecessário do sofrimento dos pacientes. Uma recente Resolução do Conselho Federal de Medicina sobre terminalidade de vida oferece aos médicos orientação sobre como lidar com algumas dessas questões de grande complexidade ética. Palavras-chave: morte encefálica, terminalidade de vida, ética

    Ethical aspects of brain death and end-of-life

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    Abstract -Ethical issues surrounding brain death and end-of-life have not been afforded in Brazil the same attention as in many developed countries. There appears to be reluctance on the part of Brazilian doctors to limit or suspend procedures or treatment which prolongs life of patients in terminal phases of severe incurable illness, or to suspend the artifi cial means of supporting vegetative functions in cases of brain death outside the context of organ and tissue donation for transplant. Fears grounded in possible administrative (Regional Medical Councils) or legal repercussions, as well as ambiguous interpretations of religious precepts, partially explain this reluctance which often results in unnecessary prolonging of patient suffering. A recent resolution by the Federal Medical Council on end-of-life may offer doctors some guidance and confi dence in dealing with highly complex ethical situations. Key words: brain death, end-of-life, ethics. Aspectos éticos da morte encefálica e terminalidade da vida Resumo -Questões éticas relativas à morte encefálica e terminalidade da vida não têm ainda no Brasil o mesmo destaque que em países desenvolvidos. Os médicos brasileiros parecem ter resistência em limitar ou suspender tratamentos ou procedimentos de prolongamento da vida em pacientes em fase terminal de doença grave e incurável, ou em suspender os meios artifi ciais da manutenção de funções vegetativas em casos de morte encefálica fora do contexto de doação de órgãos e tecidos para transplante. Receio quanto a possíveis sanções administrativas (Conselhos Regionais de Medicina) ou legais, além de duvidosas interpretações de preceitos religiosos explicam, ao menos parcialmente, essa relutância, que freqüentemente resulta em prolongamento desnecessário do sofrimento dos pacientes. Uma recente Resolução do Conselho Federal de Medicina sobre terminalidade de vida oferece aos médicos orientação sobre como lidar com algumas dessas questões de grande complexidade ética. Palavras-chave: morte encefálica, terminalidade de vida, ética

    Autonomy: an interdisciplinary approcah

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    Based on the supposition that man not born autonomous, but becomes autonomous through a process of bio-psycho-social development, a necessity arises to analyze autonomy with a social scientific focus, in such manner as to combine concepts and enable overall comprehension. This text proposes to demonstrate that in the process of biological, psychological and social development, mankind is influenced by diverse variables that will, in certain way, determine the “degree” of autonomy that is afforded to it. These variables do not negatively effect his autonomy, but to the contrary, taken together, are an integral pert of it. However, there are social-economic and cultural factors that influence the process of choosing and making a decision. These factors indeed reduce the autonomy of the individual.A partir do pressuposto de que ser humano não nasce autônomo, mas torna-se autônomo, através de um processo de desenvolvimento bio-psico-social, surge a necessidade de se analisar a autonomia sob o enfoque das ciências sociais, de modo a congregar conceitos e possibilitar a compreensão do todo. Esse texto pretende demonstrar que no seu processo de desenvolvimento biológico, psicológico e social, o ser humano é influenciado por diversas variáveis, que irão, de certa forma, determinar o “grau” de autonomia que ele possui. Essas variáveis não contaminam a sua autonomia, ao contrário, fazem parte dela. Mas, existem outros fatores sócio-econômicos e culturais que influenciam o processo de escolha e tomada de decisão. Estes fatores sim reduzem a autonomia do indivíduo

    Editorial

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    Un análisis comparativo de la inserción de inmigrantes latinoamericanos en el mercado de trabajo de España en 2001

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    Este trabajo tiene el objetivo de realizar un análisis comparativo de la situación socioeconómica de los inmigrantes latinoamericanos de origen ecuatoriano, colombiano, boliviano, peruano, venezolano y brasileño, incorporados al mercado de trabajo en España, en 2001. Se pretende investigar si existen diferencias niveles de empleo, comparando los seis grupos de latinoamericanos, y cuáles están en mejores o peores ocupaciones en el mercado de trabajo de España. También tenemos como objetivo identificar si esas diferencias de inserción laboral pueden ser explicadas por la nacionalidad de esos trabajadores, controlando las características individuales de esos trabajadores. Para investigar estos puntos, seleccionamos a los extranjeros ecuatorianos, colombianos, bolivianos, peruanos, venezolanos y brasileños, entre 25 y 65 años, en el Censo Demográfico español. En cuanto a los modelos de análisis, estimamos dos modelos de regresión logística, para verificar las diferencias relacionadas al origen étnica/nacional para la determinación de la empleabilidad e inserción ocupacional. Se mantienen las características socioeconómicas de los trabajadores constantes (sexo, edad, escolaridad, entre otras características), verificar el efecto del país de nacimiento del trabajador para explicar la situación del inmigrante en el mercado de trabajo español.The purpose of this study is to conduct a comparative analysis of the socioeconomic situation of Latin American immigrants from Ecuador, Colombia, Bolivia, Peru, Venezuela and Brazil, who were incorporated into the labor market in Spain in 2001. The aim is to investigate whether there are differences in levels of employment, comparing the six Latin American groups, and which are in better or worse occupations in the Spanish labor market. We also intend to identify if these differences in labor insertion can be explained by the nationality of these workers, controlling the individual characteristics of these workers. To investigate these points, we selected the Ecuadorian, Colombian, Bolivian, Peruvian, Venezuelan and Brazilian foreigners, between 25 and 65 years old, in the Spanish Demographic Census. Regarding the analysis models, we estimated two models of logistic regression, to verify differences related to ethnic / national origin for the determination of employability and occupational insertion. If we keep the socioeconomic characteristics of the workers constant (gender, age, schooling, among other characteristics), we will verify the effect of the country of birth of the worker to explain the situation of the immigrant in the Spanish labor market

    Phase fluctuations in the ABC model

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    We analyze the fluctuations of the steady state profiles in the modulated phase of the ABC model. For a system of LL sites, the steady state profiles move on a microscopic time scale of order L3L^3. The variance of their displacement is computed in terms of the macroscopic steady state profiles by using fluctuating hydrodynamics and large deviations. Our analytical prediction for this variance is confirmed by the results of numerical simulations
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