Stress oxydant et vieillissement

Le vieillissement est un processus qui continue à fasciner les biologistes de tous horizons, qu’ils s’intéressent à l’évolution, à la génétique, à la signalisation ou à la toxicité de l’environnement. De nombreuses théories, parfois contradictoires, sont proposées pour rendre compte des mécanismes du vieillissement, perçus par certains comme le résultat d’un programme inéluctable, par d’autres comme le fruit d’une suite d’agressions qui pourraient être évitées ou réparées. L’hypothèse « radicalaire » du vieillissement met au premier plan l’accumulation d’agressions oxydantes provoquées par les radicaux libres provenant principalement du métabolisme de l’oxygène et de l’azote. Cette hypothèse, proposée il y a une cinquantaine d’années, demeure l’une des plus populaires chez les spécialistes, même si certaines de ses prédictions n’ont pas été vérifiées de manière satisfaisante. Cet article présente les fondements de cette hypothèse, ses relations avec les autres théories, mitochondriales, métaboliques et génétiques, et la confronte à la réalité têtue des observations expérimentales pour proposer une vision plus intégrée des relations entre vieillissement et stress cellulaires.A number of theories have attempted to account for ageing processes in various species. Following the « rate of living » theory of Pearl, Harman suggested fifty years ago that the accumulation of oxidants could explain the alteration of physical and cognitive functions with ageing. Oxygen metabolism leads to reactive species, including free radicals, which tend to oxydize surrounding molecules such as DNA, proteins and lipids. As a consequence various functions of cells and tissues can be altered, leading to DNA instability, protein denaturation and accumulation of lipid byproducts. Oxidative stress is an adaptive process which is triggered upon oxidant accumulation and which comprises the induction of protective and survival functions. Experimental evidence suggests that the ageing organism is in a state of oxidative stress, which supports the free radical theory. A number of other theories have been proposed ; some of these are actually compatible with the free radical theory. Caloric restriction is among the best models to increase life span in many species. While the relationship between caloric restriction and corrected metabolic rate is controversial, the decrease in ROS production by mitochondria appears to be experimentally supported. The ROS and mitochondrial theories of ageing appear to be compatible. Genetic models of increased life span, particularly those affecting the Foxo pathway, are usually accompanied by an increased resistance to oxidative insult. The free radical theory is not consistent with programmed senescence theories involving the cell division dependent decrease in telomere length ; however, oxidants are known to alter telomere structure. An appealing view of the role of oxidative stress in ageing is the trade-off principle which states that a phenotypic trait can be evolutionarily conserved because of its positive effects on development, growth or fertility, and despite its negative effect on somatic functions and ageing. It is likely that most cellular stresses which comprise adaptive and toxic functions follow such a rule

A toxicological perspective on climate change and the exposome

Climate change is accompanied by changes in the exposome, including increased heat, ground-level ozone, and other air pollutants, infectious agents, pollens, and psychosocial stress. These exposures alter the internal component of the exposome and account for some of the health effects of climate change. The adverse outcome pathways describe biological events leading to an unfavorable health outcome. In this perspective study, I propose to use this toxicological framework to better describe the biological steps linking a stressor associated with climate change to an adverse outcome. Such a framework also allows for better identification of possible interactions between stressors related to climate change and others, such as chemical pollution. More generally, I call for the incorporation of climate change as part of the exposome and for improved identification of the biological pathways involved in its health effects

Implantação de plano de marketing como estratégia de mobilização para a qualidade

Orientador : Freddy-Jacques S. L. KesselringMonografia (especialização) - Universidade Federal do Paraná, Curso de Especialização em Gestão da QualidadeInclui referênciasResumo: O presente trabalho representa o registro do desenvolvimento do Projeto Técnico elaborado em cumprimento às diretrizes do Curso de Especialização em Gestão da Qualidade do Centro de Pós-Graduação da Universidade Federal do Paraná. A proposta refere-se ao desenvolvimento de projeto para implantação de um Plano de Marketing na Empresa Disk Mensagem. A empresa tem sede em União da Vitória - Paraná. A necessidade da elaboração de um Plano de Marketing deu-se pelo fato de que a empresa opera basicamente por telefone e necessita de um marketing agressivo para ganhar força junto às empresas concorrentes e estabelecer-se como líder na região. Na proposta desta estruturação, objeto deste projeto técnico, foi criado uma forma para através de um plano de marketing bem elaborado, aumentar a qualidade de funcionamento da empresa visando uma busca contínua pela melhoria da qualidad

Inverse correlation between phenylacetate hydrolase activity of the serum PON1 protein and homocysteinemia in humans

n/

Rastreamento do câncer de próstata em homens acima de 50 anos através do exame diagnóstico de PSA

Objetivo: Descrever a importância do rastreamento precoce do câncer de próstata em homens acima de 50 anos através do exame diagnóstico de PSA e enfatizar o sucesso deste marcador tumoral. Método: Trata-se de uma pesquisa de caráter bibliográfico através de artigos científicos localizados na base de dados eletrônicos ”“ Literatura Latino-Americana en Ciencias de la Salud (LILACS), Serviço de U.S. National Library of Medicine (PubMed) e Scientific Eletronic Library Online (SCIELO). Resultados: Foram utilizados nesta pesquisa dez artigos científicos que possuíam relação com o tema em questão, além de apresentar os descritores escolhidos neste trabalho. Conclusão: Este estudo mostrou que para o rastreamento precoce do câncer de próstata em homens acima de 50 anos de idade é essencial a realização do exame de PSA. Observa-se na literatura que a realização do toque retal associado com o marcador tumoral PSA corrobora a detecção do câncer prostático

sAOP:linking chemical stressors to adverse outcomes pathway networks

International audienceMotivation: Adverse outcome pathway (AOP) is a toxicological concept proposed to provide a mechanistic representation of biological perturbation over different layers of biological organization. Although AOPs are by definition chemical-agnostic, many chemical stressors can putatively interfere with one or several AOPs and such information would be relevant for regulatory decision-making. Results: With the recent development of AOPs networks aiming to facilitate the identification of interactions among AOPs, we developed a stressor-AOP network (sAOP). Using the 'cytotoxitiy burst' (CTB) approach, we mapped bioactive compounds from the ToxCast data to a list of AOPs reported in AOP-Wiki database. With this analysis, a variety of relevant connections between chemicals and AOP components can be identified suggesting multiple effects not observed in the simplified 'one-biological perturbation to one-adverse outcome' model. The results may assist in the prioritization of chemicals to assess risk-based evaluations in the context of human health

Special issue editorial: Key results of the european human biomonitoring initiative - HBM4EU

S

Chapter 5. Health consequences in the Mediterranean region

The Mediterranean basin is highly vulnerable to climate change, and a warming trend with changes in rainfall patterns with more heavy rains has already been observed. The frequency of dust storm and wildfire has also increased. Both non-communicable and communicable diseases will be seriously impacted by climate change since climate modification or air pollution influence the development of the former and weather conditions the latter. Different socioeconomic characteristics within the Mediterranean basin will also exacerbate or on the contrary reduce health outcomes. Surprisingly few quantitative studies have explored the impacts of climate change on health in the Mediterranean region, and the few are geographically limited to specific areas of the basin. Here we review the scientific literature on this topic and make some recommendations for the development of national and regional research, preparedness and adaptation policy in the Mediterranean region.La zone méditerranéenne est très exposée aux changements climatiques, et un réchauffement régional de la température avec une modification du régime des pluies, généralement plus fortes, est actuellement observé. Les tempêtes de sable et les incendies non contrôlés sont en augmentation. Les maladies infectieuses et chroniques humaines peuvent être affectées par ces bouleversements de façon directe ou indirecte; les conditions bioclimatiques conditionnent le développement des agents pathogènes et de leurs hôtes vecteurs ou réservoirs; les modifications du climat ou la pollution atmosphérique qui en dérive ont une influence sur le développement de certaines maladies chroniques. Des déterminants, en particulier socio-économiques, prévalant ou en évolution dans la zone méditerranéenne affecteront aussi la santé de la population. Curieusement, peu de travaux scientifiques ont étudié les effets des changements climatiques sur la santé humaine dans la région, et les quelques rares études restent géographiquement limitées à des zones particulières du bassin méditerranéen. Dans ce chapitre, nous synthétisons la recherche réalisée dans le domaine, et proposons des recommandations en termes de recherches scientifiques nationales et régionales, et de stratégies de préparation et d’adaptation à ce nouveau contexte