Serum selenium and selenoprotein P in patients with silicosis.

OBJECTIVES: Selenoprotein P (SeP) is a selenium (Se) supply protein, which is an antioxidant micronutrient considered to be vital for human health. The aim of this study was to assess the serum selenium status in patients with silicosis. METHODS: We conducted a retrospective case-control study where serum samples from a total of 78 patients (males with a median age of 73.5 years old) with silicosis and 20 healthy controls (males with a median age of 72.5 years old) were assayed for Se and SeP. They underwent medical and job history taking, lung function testing, and chest radiography examinations. Levels of serum Se were measured using electrothermal atomic absorption spectrophotomerty, while levels of SeP were assessed with sandwich Enzyme Immunoassay. Spearman's rank correlation test was carried out to evaluate the relationship between Se and SeP. The Mann-Whitney test was used to evaluate differences in serum Se and SeP between study groups. RESULTS: The median serum Se and SeP concentrations were significantly lower in cases (74.0 µg/l and 4.2mg/l, respectively) compared with controls (116.0 µg/l and 5.8 mg/l, respectively). In both cases and controls, serum Se was positively correlated with serum SeP (rho=0.781, p<0.001 and rho=0.768, p<0.001, respectively). Serum Se and SeP levels were significantly lower in patients classified in category four compared with those who were classified in category two or three. CONCLUSIONS: Serum Se and SeP concentrations were found to be at inadequate levels in patients with silicosis, and decreased significantly with the severity of the disease.

Assessment of lifestyle effect on oxidative stress biomarkers in free-living elderly in rural Japan.

BACKGROUND: Oxidative stress is believed to play a crucial role in aging and age-related diseases, and is widely thought to increase morbidity and mortality in the elderly. Assessment of biomarkers of oxidative stress, such as 8-isoprostane and 8-hydroxy-2-deoxyguanosine, are considered to be useful in predicting disease risks at the population level. OBJECTIVE: The aim of the present study was to assess the health status of the elderly by comparing their lifestyles and levels of oxidative stress biomarkers. METHODS: We carried out a cross-sectional study where urine samples from a total of 100 elderly men and women were assayed for 8-isoprostane, 8-hydroxy-2-deoxyguanosine, selenium, cadmium and creatinine. They were asked to answer a questionnaire that included questions about their lifestyle. RESULTS: Most of the participants were prehypertensive, non-alcohol users and on a rich plant-based diet. There were no differences in any biomarkers of oxidative stress between men and women. 8-Isoprostane was found to correlate positively with systolic blood pressure in women, but not in men. There was a slight increase of 8-isoprostane in participants with a poor intake of vegetables, and a decrease of 8-hydroxy-2-deoxyguanosine in participants who consumed fish. Multiple regression analysis showed that oxidative stress biomarkers were positively associated with cadmium, and negatively associated with selenium and fish intake in all participants, 89% of which were non-smokers. CONCLUSION: Results from the present study show that fish intake has the potential of decreasing oxidative stress among elderly persons.