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Biomedical subjects

S M Cardoso

Publications and source records attributed to S M Cardoso.

9 recordsLinked to original sources
PubMed2000

[An evaluation of the impact of cardiovascular disease prevention in Portugal (1980-1996). A longitudinal Gompertzian analysis of mortality].

The behaviour of cardiovascular diseases has suffered important modifications in recent years. There have been increases in mortality and morbidity in some countries while others have seen stabilization and even reduction. In the countries where we have observed a reduction in cardiovascular mortality, the reasons are multiple: efficacy of prevention measures; improvement of environmental conditions; increase in survival; and competitiveness with other causes of death. In order to ascertain whether a certain tendency is real or fictitious, we need to use techniques that allow the evaluation of the true evolution, to study the effect of environmental factors (not genetic) and the variability of internal resistance (vitality) to disease. Based on the longitudinal Gompertzian analysis of mortality for ischemic heart disease (IHD) and cerebrovascular disease (CVD) between 1980 and 1996, it was possible to observe a reduction in mortality for both causes, which was more obvious in the case of CHD, and that the impact of the improvement in environmental conditions (not genetic) was higher in CVD versus IHD. The prevention of CVD was more efficient in men (42.8% vs 29.7%) than in women, while in IHD the most efficient prevention was 20.6% in women versus 14.9% in men, comparing the data of 1996 and 1980. During this period, the environmental influences (not genetic) were responsible for the reduction in mortality for IHD in 2.7% of men and 4.3% of women, while in CVD we observed a reduction in mortality of 7.5% in men and 4.5% in women.

Adult↗
PubMed1999

Mitochondrial function is differentially affected upon oxidative stress.

The mechanisms that lead to mitochondrial damage under oxidative stress conditions were examined in synaptosomes treated with ascorbate/iron. A loss of membrane integrity, evaluated by electron microscopy and by LDH leakage, was observed in peroxidized synaptosomes and it was prevented by pre-incubation with vitamin E (150 microM) and idebenone (50 microM). ATP levels decreased, in synaptosomes exposed to ascorbate/iron, as compared to controls. NADH-ubiquinone oxidoreductase (Cx I) and cytochrome c oxidase (Cx IV) activities were unchanged after ascorbate/iron treatment, whereas succinate-ubiquinone oxidoreductase (Cx II), ubiquinol cytochrome c reductase (Cx III) and ATP-synthase (Cx V) activities were reduced by 55%, 40%, and 55%, respectively. The decrease of complex II and ATP-synthase activities was prevented by reduced glutathione (GSH), whereas the other antioxidants tested (vitamin E and idebenone) were ineffective. However, vitamin E, idebenone and GSH prevented the reduction of complex III activity observed in synaptosomes treated with ascorbate/iron. GSH protective effect suggests that the oxidation of protein SH-groups is involved in the inhibition of complexes II, III and V activity, whereas vitamin E and idebenone protection suggests that membrane lipid peroxidation is also involved in the reduction of complex III activity. These results may indicate that the inhibition of the mitochondrial respiratory chain enzymatic complexes, that are differentially affected by oxidative stress, can be recovered by specific antioxidants.

Adenine Nucleotides↗
PubMed1998

The protective effect of vitamin E, idebenone and reduced glutathione on free radical mediated injury in rat brain synaptosomes.

In the present study the effect of ascorbate (0.8 mM)/iron (2.5 microM) on lipid and protein oxidation, in Synaptosomes isolated from rat brain cortex, was evaluated. Vitamin E, idebenone and reduced glutathione were used as free radicals scavengers, in order to analyze the mechanism involved in ascorbate/iron-induced oxidative stress. An increased formation of reactive oxygen species (ROS) in the cytosol and in the mitochondria was observed, in ascorbate/iron treated synaptosomes. Idebenone (50 microM) prevented the increased formation of ROS in both synaptosomal compartments, vitamin E (150 microM) protected partially this formation in mitochondria, whereas reduced glutathione (250 microM) (GSH) was ineffective. After ascorbate/iron treatment an increase in lipid peroxidation occurred as compared to control, which was completely inhibited by idebenone. A decrease in protein-SH content was also observed, and it was prevented by Vitamin E, idebenone and GSH. When synaptosomes were treated with ascorbate/iron the levels of GSH decreased, and the levels of oxidized glutathione (GSSG) increased as compared to controls under these conditions. Glutathione peroxidase activity was unchanged, whereas an inhibition of glutathione reductase activity was observed. These data suggest that the increased formation of free radicals in synaptosomes leads to lipid and protein oxidation, the role of the endogenous GSH being essential to protect protein thiol-groups against oxidative damage in order to maintain enzyme activity.

Adenine Nucleotides↗
PubMed1998

[Measurement discrepancies (analysis of consistency between 2 methods)].

Our purpose was to study the agreement between two methods with clinical impact. Usually, many techniques are not correct for the analysis of concordance. Otherwise, it is normal to confuse association and concordance. We intend to prove that two methods can show a strong association and a weak concordance. Nowadays we must replace "old" methods with new ones, which are more correct and efficient for clinical and research goals.

Biometry↗
PubMed1998

[The spatial grouping of myocardial infarct in Portugal. The application of the methods of Grimson and of Moran].

OBJECTIVES: The objective of this study was to apply techniques of space grouping (clusters) to identify the existence of eventual clusters. The application of these techniques to illnesses, such as cardiovascular ones, may generate work hypotheses, in order to know the dynamics of the risk factors. MATERIAL AND METHODS: We used two techniques, Grimson's test and the Moran's I for the study of the behaviour of standardised mortality ratio (SMR) for myocardium infarction at a municipal level. The SMR had been calculated by municipalities, for men, women and both in the period of 1985-1989, based on the data of the INE. RESULTS: We verified that any of the two methods suggests the existence of clusters for the infarct of the myocardium, identifying regions in the country in which SMR are above that expected, implying the presence of "identical denominators" or other common ones. CONCLUSIONS: The use of these techniques for cardiovascular illnesses could be useful as a scientific form of identifying regions of high and low risk, making it possible for epidemiological studies to be made of the different known and unknown risk factors contributing to the implementation of preventive measures.

Cluster Analysis↗
PubMedDate not supplied

[The prevalence of cerebrovascular stroke in Coimbra].

The purpose of this study was to assess the prevalence of strokes in a community-based on a sample of the population of the county of Coimbra in 1992 (139,000 inhabitants). The study was made with the collaboration of local general practitioners who randomly selected a sample of 950 individuals over 50 years of age. These individuals were screened for the presence of vascular risk factors and strokes in the past, and submitted to clinical and laboratory examinations. There were 86 persons with strokes (crude prevalence 8%: 10.2% male, 6.6% female) the diagnosis being confirmed by neurological examination or analysis of hospital registers. Hypertension was significantly more frequent in patients with strokes (56.8%). Other risk factors had no significant differences. The magnitude of disability associated with stroke was assessed according to the modified Rankin scale. About fifty percent had no significant disability or a slight disability and 20% were severely disabled.

Age Distribution↗