Browsing by Author "Santos, Maria Cristina"
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- Antioxidant markers and cardiovascular risk factors in Azorean subjects with coronary artery diseasePublication . Ferin, Rita; Gomes, Carla; Castro, Ana Rita; Martins, Dinis; Santos, Víctor; Santos, Maria Cristina; Lopes, Paula Alexandra; Baptista, José; Viegas-Crespo, Ana Maria; Pavão, Maria LeonorTo evaluate some blood antioxidant parameters in azorean subjects with coronary artery disease (CAD) previously submitted to percutaneous revascularization (PCI), by considering some cardiovascular risk factors.
- Blood antioxidant markers and elemental levels in Azorean patients with coronary artery disease: a preliminary studyPublication . Ferin, Rita; Napoleão, Patrícia; Gomes, Carla; Castro, Ana Rita; Lopes, Paula Alexandra; Martins, Dinis; Santos, Maria Cristina; Viegas-Crespo, Ana Maria; Pinheiro, Teresa; Pavão, Maria LeonorAtherosclerosis (ATH) and related vascular diseases are the first cause of morbidity and mortality in Portugal, including the Azores’ Archipelago. The oxidation of low density lipoproteins (LDL) is considered to be an important event in the development of the disease. Accordingly, by preventing LDL oxidation, antioxidants can possibly reduce the risk or the progression of ATH. Essential trace elements as Cu, Se, Zn, and Fe are involved in endogenous antioxidant systems, mainly as cofactors of antioxidant enzymes. Other elements, like K and Ca, might play a role in atherogenesis while implicated in physiological and metabolic processes which are known to be disturbed in ATH. The aimof the present study was to evaluate some blood antioxidant markers and blood elemental levels in 20 Azorean subjects (ten men and ten women, aged 40 to 65 years) with coronary artery disease previously submitted to percutaneous revascularization (PCI). The whole blood gluthatione peroxidase (Se-GPx) and erythrocyte superoxide dismutase activities were measured, as well as serum vitamin E levels (by HPLC). The concentrations of K, Ca, Fe, Cu, Zn, and Se in plasma and blood cells were determined by PIXE. Results were analyzed by taking into account several cardiovascular risk factors, namely, gender, hypertension, dyslipidemia, and total plasma homocysteine (tHcy) concentration. Se-GPx activity and vitamin E levels were significantly lower (24 and 15%, respectively) in the PCI group than in controls. In blood cells, significantly differences in Ca (19±5 vs 24±6 μg/mL) and Zn (14±1 vs 12±2 μg/mL) levels were observed in PCI women (but not in men) compared to the respective counterparts. Also in PCI women, both serum triglyceride and plasma tHcy concentrations were above reference values and higher than in men. Results suggest a decreased antioxidant status in PCI patients. In particular, women appear to be less protected than men, as reflected in some cardiovascular risk factors.
- Blood antioxidant parameters and cardiovascular risk factors in subjects from the city of Ponta Delgada (Azores' Archipelago, Portugal)Publication . Pavão, Maria Leonor; Figueiredo, Teresa; Santos, Víctor; Lopes, Paula Alexandra; Ferin, Rita; Santos, Maria Cristina; Vicente, Luís; Viegas-Crespo, Ana Maria; Nève, JeanThe purpose of this work was to evaluate serum selenium, copper and zinc concentrations, as well as the whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities in subjects from the city of Ponta Delgada (S. Miguel Island, Azores’ Archipelago). The study of their relationship with generally accepted cardiovascular risk factors was also an objective. […].
- Blood antioxidant parameters in subjects from Azorean populations with different sociocultural profilePublication . Pavão, Maria Leonor; António, Sílvia; Figueiredo, Teresa; Santos, Maria Cristina; Nève, Jean; Viegas-Crespo, Ana MariaAge, sex, physiological and pathological conditions, as well as geographical location reflected in diet, social and environmental conditions and even in life habits are relevant factors in the assessment of the prooxidant/antioxidant status of individuais. The aim of this work is to compare some antioxidant parameters, such as whole blood Se-glutathione peroxidase (GSH-Px) and erythrocyte Cu, Zn-superoxide dismutase (SOD) activities, serum selenium, copper and zinc leveis in healthy subjects from three populations with different sociocultural characteristics. Volunteer men and women aged 20-60 were selected from Ponta Delgada (urban population), Ribeira Quente (fishing population) and Água Retorta (rural population) located in the island o f S. Miguel (Azores’ Archipelago, Portugal). No significant differences in GSH-Px activity were found in interpopulation analysis, but the activity tended to be higher in women than in men; in turn, selenium levels, which were maximum in subjects from Ribeira Quente, were significantly bigher in male than in female groups, except in the rural population where they were similar. SOD activities, as well as zinc leveis were significantly higher in both men and women from the fishing population than in the others, where they did not differ. Also SOD, but not zinc or copper, was higher by 13% in women than in men from Ribeira Quente. The rural population exhibited the highest copper concentrations, being much higher in these women than in those from Ribeira Quente or Ponta Delgada. Diet, either food or drinking water might be a major cause for the differences observed.
- Blood elemental levels and antioxidant markers in humans with atherosclerotic diseasePublication . Lopes, Paula Alexandra; Napoleão, Patrícia; Pinheiro, Teresa; Santos, Maria Cristina; Rodrigues, Maria Odete; Ceia, Fátima; Vicente, Luís; Mathias, Maria da Luz; Pavão, Maria Leonor; Nève, Jean; Viegas-Crespo, Ana MariaAlthough mortality from coronary heart disease has declined recently, atherosclerosis and related vascular diseases are still the major cause of death in the western countries. Experimental studies have demosntrated that a disturbed balance between free radical formation and antioxidant defenses can play a role in the development and progression of various diseases, namely atherosclerosis. In this study trace element levels were measured in plasma and in blood cells of subjects suffering from atherosclerotic disease. Blood activities of antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPx) and plasma total thiols were also evaluated in these patients. Significantly decreased Se and Fe were found in the blood plasma of the atherosclerotic group. A tendency for disruption in antioxidant enzyme status was observed in these patients, but plasma total thiols were unchanged. These are preliminary results and a large atherosclerotic group is required in order to clarify the observations and to contribute for the knowledge on the molecular basis of atherosclerosis.
- Blood trace element levels in patients with stabilized atherosclerosisPublication . Viegas-Crespo, Ana Maria; Napoleão, Patrícia; Lopes, Paula Alexandra; Santos, Maria Cristina; Pavão, Maria Leonor; Pinheiro, TeresaCardiovascular diseases remain the leading cause of mortality in Western populations. Dislipidemia, hypertension, diabetes, obesity and tobacco consumption are the main risk factors for atherosclerosis and its thrombotic complications. However, these factors alone cannot account for all of the deaths caused by vascular pathologies. The possible interaction of some trace element levels with atherogenic diseases is not completely clarified. On the other hand, the intra and extracellular concentrations of elements playing an important function in the electrolytic equilibrium could partially be associated with cardiovascular dysfunctions and other associated pathologies. The aim of this study was to evaluate trace elements (Fe, Ni, Cu, Zn, Se) and electrolytic –balance associated elements (Ca and K) in plasma and blood cells of patients with stabilized atherosclerosis. Significant differences between patient and control groups were observed in blood cells for the K, Fe, and Zn concentrations, while plasma K, Ca, Fe and Zn levels exhibited significant differences between groups. Results will be discussed taking into account the main function of those elements and the etiology of atherosclerosis. The relationship of results with the studied cardiovascular risk factors will be also considered.
- Comparison of Apolipoprotein E polymorphism and other atherosclerotic risk factors in two Portuguese populations: the Influence of InsularityPublication . Lopes, Paula Alexandra; Gaspar, Gisela; Napoleão, Patrícia; Santos, Maria Cristina; Pavão, Maria Leonor; Viegas-Crespo, Ana MariaO principal objectivo deste estudo é o de pesquisar o efeito da insularidade nos polimorfismos da apolipoproteína (apo) E em indivíduos saudáveis do continente (Lisboa) e de Ponta Delgada (Ilha de S. Miguel, Arquipélago dos Açores). Adicionalmente, estudar a distribuição dos seus genótipos em doentes com aterosclerose da Ilha de S. Miguel. Em Lisboa, a distribuição dos genótipos da apo E foi a seguinte: e3/e3 > e3/e4 > e2/e3 > e4/e4, ao passo que em Ponta Delgada e independentemente da condição fisiológica foi: e3/e3 > e2/e3 > e3/e4. Distintas frequências genotípicas foram observadas entre homens e mulheres no grupo saudável de Ponta Delgada. O índice de massa corporal, hipertensão arterial e perfil lipídico, factores de risco associados ao processo aterosclerótico, revelaram algumas diferenças quando avaliados em função dos grupos alélicos. Neste estudo, os genótipos de risco da apo E, e2/e2 and e2/e4, não foram contabilizados. Curiosamente a proporção dos genótipos nas mulheres foi heterogénea nos 3 grupos estudados.
- Comparison of whole blood glutathione peroxidase activity, levels of serum selenium and lipid peroxidation in subjects from the fishing and rural communities of "Rabo de Peixe" Village, San Miguel Island, The Azores Archipelago, Portugal.Publication . Pavão, Maria Leonor; Cordeiro, Carla; Costa, Ângelo; Raposo, José Aires; Santos, Maria Cristina; Nève, Jean; Viegas-Crespo, Ana MariaThe activity of glutathione peroxidase (GSH-Px), serum selenium (Se), and thiobarbituric acid reactive substances (TBARS) were measured in the whole blood of 148 healthy adults aged 20–60 yr from the fishing and rural communities of “Rabo de Peixe,” The Azores, Portugal. The subjects did not live in the same household and had different socioeconomic profiles and dietary habits. The serum lipid profile and selected life habits were also considered in this study. No significant differences in the activity of GSH-Px were found in the interpopulation or intrapopulation analyses, classified by age or lipid profile. An age-dependent GSH-Px increase was noted in the younger male (M) subgroups (20–39 yr). The Se levels were higher in fishers (f) of both genders (M, F) than in subjects living in the rural (r) environment: 110±25 µg/L (f, M), 89±20 µg/L (f, F), 88±22 µg/L (r, M) and 80±17 µg/L (r, F). In the fishers, but not in the rural population, Se was higher in the males, but it did not show significant variation with age. The levels of TBARS were lower in the f than in the r male group. The Se level was lower and TBARS higher in the hyperlipemic women in the f group, compared to the corresponding controls. Our results suggest that the fishers (mainly men) show a better antioxidant status than that of their rural counterparts, due to differences in dietary habits between the study populations and between genders.
- Dietary selenium intake and antioxidant defenses in tissues of peripuberal ratsPublication . Santos, Maria Cristina; Nève, Jean; Pavão, Maria Leonor; Viegas-Crespo, Ana MariaFree radicais are highly reactive chemical species that can oxidize and damage essential biological molecules. Their formation is a result of endogenous metabolism or of xenobiotics bio-transformation, but under normal physiological conditions cells are protected against oxidative challenge by enzymatic and non enzymatic antioxidants (Sies and Groot, 1992; Yu, 1994). Selenium (Se) is a trace element which essentiality for animais and humans is now well established. The element performs its functions mainly through selenoproteins and several glutathione peroxidases that degrade hydroperoxides using glutathione (GSH) as a reducer, are selenoenzymes playing an important role as antioxidant defenses (Ursini, Maiorino and Gregolin, 1985; Flohé, 1989). However, selenium is also a toxic agent with a narrow range of suitable levels. The main objective of this study was to assess the physiological development of some antioxidant parameters in liver and testes of rats during the puberty until the adult hood and to know if a low selenium supplementation in the diet can have some effect on those parameters, especially on those related with glutathione metabolism. (Introduction)
- Influence of dyslipidemia and smoking on redox markers in humans: a critical studyPublication . Lopes, Paula Alexandra; Rodrigues, Olívia Roos; Napoleão, Patrícia; Pavão, Maria Leonor; Nève, Jean; Santos, Maria Cristina; Viegas-Crespo, Ana MariaNa actualidade, é consensual que os processos oxidativos desempenham um papel importante no aparecimento e progressão de inúmeras doenças. O conhecimento do comportamento, dos parâmetros do balanço redox, poderá surtir efeito na prevenção da ocorrência de tais patologias. OBJECTIVOS: o presente estudo numa perspectiva pioneira para uma população portuguesa (a de Lisboa) visa caracterizar a variação de parâmetros sanguíneos associados ao sistema pró-oxidante/antioxidante tendo em consideração variáveis como o sexo, a idade, o perfil lipídico e hábitos de vida, como o tabagismo. CONCEPÇÃO DO ESTUDO E PARTICIPANTES: 183 indivíduos saudáveis de ambos os sexos, com idades compreendidas entre os 20 e os 70 anos e residentes na área metropolitana de Lisboa foram recrutados aleatoriamente no Instituto Nacional de Saúde Dr. Ricardo Jorge, enquanto utentes deste laboratório de referência. A avaliação clínica dos participantes foi efectuada com recurso a questionário. Em presença de doenças agudas/crónicas ou de ingestão de suplementos nutricionais e medicação, os indivíduos foram excluídos do estudo por forma a não haver interferência nos resultados dos marcadores a analisar. MATERIAL E MÉTODOS: A actividade da enzima glutationo peroxidase no sangue total e as concentrações serológicas de albumina, transferrina e ácido úrico foram determinadas com recurso a kits comerciais. Por seu lado, a actividade enzimática da superóxido dismutase nos eritrócitos e das substâncias reactivas com o ácido tiobarbitúrico no soro foram quantificadas com recurso a protocolos experimentais disponíveis na literatura da especialidade. RESULTADOS PRINCIPAIS: A actividade da enzima glutationo peroxidase não foi afectada por nenhuma das variáveis estudadas mas a actividade da superóxido dismutase decresceu significativamente com o tabagismo. As concentrações de albumina mantiveram-se idênticas em qualquer das situações estudadas. As concentrações de transferrina e de ácido úrico foram manifestamente condicionadas pela variável sexo. Ao estado fisiológico de hiperlipidemia foram associados níveis comparativamente mais elevados de peroxidação lipídica assim como de ácido úrico. Por último, a aplicação inovadora de um modelo multivariado de tratamento estatístico separou com clareza os sexos e o perfil lipídico e os sexos e os hábitos tabágicos, respectivamente. CONCLUSÕES: O presente estudo, sugere relevância para considerar no futuro, a hiperlipidemia e o tabagismo como importantes critérios de selecção em estudos epidemiológicos relacionados com o stresse oxidativo, como os envolvidos no processo aterosclerótico.