Markers of oxidative stress in fit, health-conscious elderly people living in the Paris area. The Research Group on Ageing (GERBAP)

Lipid peroxidation index and antioxidant indicators were assessed by biochemical means in 193 healthy elderly volunteers (103 men and 90 women), ages 70-89 y and living freely in the Paris area. Lipid peroxidation index was in the same range as in young adults. Zinc, copper, and selenium levels were satisfactory and similar to those in young adults, though the range of copper values tended to be higher. Copper and selenium levels were higher in elderly women than in men. However, for selenium values this sex-related difference disappeared in elderly volunteers > 75 y. Copper-zinc-superoxide dismutase and glutathione peroxidase activities were similar to those in young adults, with no influence of sex or age. Vitamin E and total carotene, closely related to cholesterol levels, were satisfactory. Our findings show that markers of oxidative stress are not influenced by old age when good health and nutritional status are preserved, as in this selected population.

Immunoglobulin A levels in bronchial samples during mechanical ventilation and onset of nosocomial pneumonia in critically ill patients

Local immunoglobulins play a key role in host defense against lung infection. We investigated the pattern of evolution of bronchial albumin, IgA, and IgG levels in ventilated ICU patients in relation to nosocomial pneumonia. Immunocompetent, critically ill patients underwent serial blood and bronchial protein determinations on Day 1 (intubation day), and on Days 3, 7, 10, and 14. The variations in proteins levels were compared with corresponding Day 1 values in the whole population, and between patients who developed lung infections (Group A) and the remaining population (Group B). Forty-four patients were included into the study. In the whole population, when compared with the baseline value, bronchial IgA/albumin ratio increased significantly (Day 3, +58%, p = 0.04); Day 14, +171%, p < 0.01), but serum IgA/albumin and serum and bronchial IgG/albumin ratios did not change significantly. In Group A, the increase in the IgA/albumin ratio was less than in Group B (Day 3, +15% versus +87%, p = 0.04; Day 14, +29% versus +210%, p < 0.01). No significant differences were observed between the two groups for bronchial and plasma albumin and IgG levels and for bronchial polymorphonuclear elastase levels. Bronchial IgA production was enhanced in ventilated patients. A reduction in this enhanced bronchial IgA production might account for the development of nosocomial pneumonia.