It has been reported that oxidative stress may play a role in the pathogenesis of dementia of the Alzheimer type (AD) and the cerebral ischemia which causes vascular dementia (VD). We measured malondialdehyde (MDA) levels and superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities in blood samples from patients with AD and VD and in healthy non-demented controls (CTR) which similar ages to the patients, in order to evaluate the degree of oxidative stress in patients with AD and VD. A sample of 150 subjects consisting of 50 patients with AD; 50 patients with VD and 50 CTR, aged from 65 to 85 years on, was analyzed. Most of the changes observed were in SOD activity and MDA levels. Catalase activity were least affected. Significant differences were observed in SOD and GR activity between males and females in CRT and in patients with AD, but not in VD. We have found a decrease in antioxidant enzymes activities (SOD, CAT, GPx and GR) in patients with AD and VD and significant differences were observed between CRT and AD patients for ages from 65 to 74, 75 to 84 and from 85 years to 94 years in SOD activity and MDA levels (P < 0.001). MDA levels increase with age in VD, AD and CTR. No significant variation with respect to sex were detected, but significant variations in MDA levels were detected between CRT and patients with VD and AD (P < 0.001). We conclude that oxidative stress plays an important role in the brain damage for both AD and VD, being observed higher levels of oxidative stress for AD that for VD.

Stressful conditions lead to formation of excessive reactive oxygen species (ROS) and cause oxidative stress and aging. The aim of this study was to determine superoxide dismutase (SOD) and catalase (CAT) activity, and malondialdehyde (MDA) levels in nurses of a hospital intensive care unit according to demographic and occupational parameters, and to analyse the relationship with aging. Thirty-two nurses working in an intensive care unit and 35 aged-matched healthy individuals of both sexes as a control group were surveyed. No significant variations with respect to sex were detected in SOD, CAT, MDA and burnout levels. MDA levels increased with age in both the control group and the nurses, and we observed significant differences in MDA levels between the control group and nurses for all age groups. Significant variations in MDA levels were detected between single (286.12±8.41) and married (318.82±6.02), people, between those who frequently practice some kind of sport (281.41±7.32) and those who never participate in sport (298.24±8.11) ,and between those who frequently eat fruit and greens (289.75±8.41) and those who never eat them (315.12± 7.21). Significant differences were detected between smokers and nonsmokers in SOD, CAT and MDA, but not for alcohol, coffee, tea or cola consumption. Higher SOD activity and MDA levels were detected in nurses on evening and night shifts (P<0.01); these nurses also scored significantly higher on burnout subscales. These results suggest that: (1) occupational stress increases oxidative stress levels as a response to elevated ROS generation; (2) occupational stress increases MDA levels as a response to an elevation in free radical generation and can lead to aging; (3) working evening and night shifts increases oxidative and burnout levels. It is evident that preventive changes in job conditions and lifestyle are necessary to improve the quality of life of nurses who work in intensive care units.

Our findings suggest that oxidative stress, occupational stress and occupational burnout levels are similar in men and women. Occupational stress increases oxidative stress levels probably as a response to increased generation of reactive oxygen species. Working during the evening and night shifts increases oxidative levels and burnout levels.

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In order to investigate the role of two free radical detoxificant enzymes in patients with aging brain disorders, superoxide dismutase (SOD) and catalase (CAT) activities have been measured in blood from male and female human patients of different ages with several types of aging brain disorders. When compared with activities in the normal population, we have detected: 1) SOD and CAT activities are decreased in patients with Parkinson disease. 2) SOD activity seems to be normal and CAT activity is decreased in patients with dementia. 3) In the patients with stroke, SOD activity is normal, while CAT activity is decreased. SOD activity was measured in red blood cells using the Minami and Yoshikawa method. CAT activity was measured in hemolysates by the method of Aebi. We can conclude that SOD and CAT activities in patients with Parkinson disease are decreased.

Our results confirm an increase in lipid peroxidation in patients with DS.

Superoxide dismutase is an enzyme that catalyzes the dismutation of superoxide radicals to hydrogen peroxide and molecular oxygen. This superoxide radical is produced by all aerobic cells as a normal metabolic intermediate of molecular oxygen, and is dangerous for the cell because it induces the inactivation of various enzymes, lipid peroxidation and mutations. Superoxide dismutase can therefore be considered as a protective enzyme. The purpose of this work was to determine the level of superoxide dismutase activity in the Spanish population, and to study the factors that influence this activity. The superoxide dismutase activity of 2397 individuals was determined using the method described by Minami and Yoshikawa. The superoxide dismutase activity level in the adult Spanish population was found to be 4.16 +/- 0.89 Units/ml of blood. No significant variations with respect to sex were detected. But it was observed that the superoxide dismutase activity level was 9% higher in the young urban Spanish population.