Ciencia, vino y salud

A large number of prospective studies have observed an inverse relationship between a moderate intake of alcohol and coronary heart disease morbidity and mortality. Concerning death from all-causes, results are not unanimous. Alcohol intake was associated with a protection of all-cause mortality in England and USA physicians and the large study of the American Cancer Society. None of these studies separated the effects of different alcoholic beverages. In our prospective studies in France on 35 000 middle-aged men, we observed that only wine at moderate intake, was associated with a protective effect on all-cause mortality. The reason was that in addition to the known effect on cardiovascular diseases, a very moderate intake of wine, protected also from cancer and other causes as confirmed by Gronbaek in Denmark. Our recent results also indicate that the protective effect of a moderate intake of wine on all-cause mortality is observed at all levels of blood pressure and serum cholesterol.

Ingesta de nutrientes en adultos mayores de la comuna de Providencia, Santiago de Chile / Nutrients intake in elderly people living in Providence, Santiago de Chile

BACKGROUND: The information available on food intake in the elderly in Chile is restricted to individuals of low socioeconomic groups, but there is no data available on food intake in elderly of higher income groups. AIM: To assess food intake in a group of elderly people from Providencia County in Santiago, a middle income community. SUBJECTS AND METHODS: Forty one subjects (20 male), aged 60 to 73 years, were studied. Trained volunteers applied a 3 days food registry, to determine food intake. Intake was assessed using 1985 FAO/OMS/UNU recommendations for energy intake and USA Food and Nutrition Board recommendations for micronutrient intake. RESULTS: The studied subjects had an adequate macronutrient intake, when compared with current recommendations. There was a relatively low intake of calories from fat (24.6 per cent in males and 26.1 per cent in females). Also, vitamin and mineral intake was adequate with the exception of calcium (64.5 per cent and 57.9 per cent of recommendation in males and in females respectively), zinc and folic acid (74.2 per cent and 62.4 per cent in males and females respectively). The intake of legumes and cereals was relatively low. CONCLUSIONS: Food intake in this group of individuals was substantially higher than that reported previously for poor elderly Chileans and similar to that of industrialized countries. Food intake of the elderly is probably related to socioeconomic level.

Endothelial cell oxidative stress and signal transduction

Endothelial dysfunction (ED) is an early event in atherosclerotic disease, preceding clinical manifestations and complications. Increased reactive oxygen species (ROS) have been implicated as important mechanisms that contribute to ED, and ROS's may function as intracellular messengers that modulate signaling pathways. Several intracellular signal events stimulated by ROS have been defined, including the identification of two members of the mitogen activated protein kinase family (ERK1/2 and big MAP kinase, BMK1), tyrosine kinases (Src and Syk) and different isoenzymes of PKC as redox-sensitive kinases. ROS regulation of signal transduction components include the modification in the activity of transcriptional factors such as NFkB and others that result in changes in gene expression and modifications in cellular responses. In order to understand the intracellular mechanisms induced by ROS in endothelial cells (EC), we are studying the response of human umbilical cord vein endothelial cells to increased ROS generation by different pro-atherogenic stimuli. Our results show that Homocysteine (Hcy) and oxidized LDL (oxLDL) enhance the activity and expression of oxidative stress markers, such as NFkB and heme oxygenase 1. These results suggest that these pro-atherogenic stimuli increase oxidative stress in EC, and thus explain the loss of endothelial function associated with the atherogenic process.

A comparison of methods employed to evaluate antioxidant capabilities

Three different methodologies frequently employed to evaluate the indexes that report the antioxidant capabilities of pure compounds and/or complex mixtures of antioxidants are applied to a series of mono- and polyphenols, as well as to two wine (red and white) samples. These methodologies are based on the bleaching of a stable radical, the effect of the additive upon luminol chemiluminescence induced by peroxyl radicals, and the effect of the additive upon the bleaching of the fluorescence from a dye molecule. Widely different responses are obtained from the different methodologies. These differences are interpreted in terms of the different factors (stoichiometric factors and/or reactivities) that determines the indexes evaluated by these different methodologies.

Plant polyphenol antioxidants and oxidative stress

In recent years there has been a remarkable increment in scientific articles dealing with oxidative stress. Several reasons justify this trend: knowledge about reactive oxygen and nitrogen species metabolism; definition of markers for oxidative damage; evidence linking chronic diseases and oxidative stress; identification of flavonoids and other dietary polyphenol antioxidants present in plant foods as bioactive molecules; and data supporting the idea that health benefits associated with fruits, vegetables and red wine in the diet are probably linked to the polyphenol antioxidants they contain. In this review we examine some of the evidence linking chronic diseases and oxidative stress, the distribution and basic structure of plant polyphenol antioxidants, some biological effects of polyphenols, and data related to their bioavailability and the metabolic changes they undergo in the intestinal lumen and after absorption into the organism. Finally, we consider some of the challenges that research in this area currently faces, with particular emphasis on the contributions made at the International Symposium [quot ]Biology and Pathology of Free Radicals: Plant and Wine Polyphenol Antioxidants[quot ] held July 29-30, 1999, at the Catholic University, Santiago, Chile and collected in this special issue of Biological Research.

Introduccion practica del estudiante de medicina a la investigacion biomedica. / Practical introduction of the medical student in biomedical research

Refere-se este trabalho a um curso ministrado no Instituto de Ciencias Biologicas da Universidade Catolica do Chile, mediante o qual os alunos do terceiro ano de medicina, trabalhando como auxiliares, sao iniciados na pesquisa biomedica. O primeiro objetivo do curso e o aprendizado do metodo cientifico sob um regime preceptorial. Esse curso optativo e dirigido e coordenado por um professor-responsavel e integrado por professores-orientadores ativos na pesquisa. Os alunos escolhem o tema do trabalho, de umalista de projetos apresentada pelos professores-orientadores atraves do responsavel. A avaliacao do estudante leva em conta sua participacao na execucao e discussao do trabalho, a apresentacao na reuniao final do curso e o manuscrito. Nos ultimos dez anos, 47% dos terceiranistas de medicina optaram pelo curso e foram aprovados com notas satisfatorias. O rendimento tem melhorado, como o demonstra o fato de haverem sido publicados, nos ultimos seis anos, os resultados de dez projetos desenvolvidos durante o curso. O aluno disposto a continuar sua pesquisa pode-se candidatar ao posto de auxiliar-aluno, oferecido por concurso pela Escola de Medicina, assim habilitandose a completar sua formacao cientifica e o projeto iniciado