The reduction of nitroblue tetrazolium by red blood cells: a measure of Red Cell membrane antioxidant capacity and hemoglobin-membrane binding sites.

The reduction of nitroblue tetrazolium (NBT) with intact Red Blood Cells (RBCs) is biphasic with an initial rapid reduction followed by a slower second phase. This biphasic kinetics has been explained with the initial rapid phase attributed to antioxidants in the red cell which reduce membrane bound NBT and the slower phase associated with the reaction of NBT with membrane bound hemoglobin. This model has been confirmed by a utilization of a number of red cell modifications which either increase the red cell antioxidants (vitamin C and vitamin E) or damage the red cell membrane (cumene hydroperoxide and N-ethylmaleimide). The utilization of this assay for human blood samples was investigated by studying a series of 20 human subjects ranging between 34 and 87 years of age. It was possible to fit all of these samples with two adjustable parameters which reflect the red cell membrane antioxidant capacity (x) and the hemoglobin membrane interactions (m). The antioxidant capacity shows a significant (p < .002; R = -.67) decrease with age. This finding is consistent with a decrease in the level of antioxidants in aged subjects. In addition, the number of hemoglobin membrane sites are negatively correlated with the antioxidant capacity (p < .02; R = -.52) suggesting that the oxidative stress associated with reduced antioxidants results in increased hemoglobin-membrane interactions.

Oxidative stress and hemorheological changes induced by acute treadmill exercise.

The present investigation was designed to evaluate the acute effect of aerobic exercise on oxidative stress and the flow properties of the blood. Fourteen clinically healthy subjects (7 men and 7 women aged 56+/-19 yr) underwent maximal treadmill exercise with blood samples drawn prior to and immediately after exercise. Post-exercise significant increases were observed in plasma lipid hydroperoxides from 6.5+/-2.0 microM to 7.9+/-1.9 microM (p<0.0001) and the relative concentration of plasma fluorescent products associated with red cell peroxidation from 138+/-28 RF to 220+/-92 RF (p<0.005). After exercise there was a rise in the hematocrit from 41.4+/-3.7% to 44.4+/-4.1% (p<0.0001), increases in whole blood viscosity at shear rates of 22.5/sec to 450/sec (p<0.0005), an increase in plasma viscosity from 1.27+/-0.12 cP to 1.36+/-0.11 cP (p<0.01), an increase in red cell rigidity from 2.44+/-0.48 cP to 2.62+/-0.42 cP (p<0.001) and a decrease in erythrocyte sedimentation rate from 26.9+/-18.6 mm/h to 22.5+/-15.9 mm/h (p<0.01). The findings suggest that acute aerobic exercise induces oxidative damage to red blood cells and adversely affects rheological properties of the peripheral blood.

[In Nigeria: sexual permissiveness and sex education]. / Au Nigéria: laxisme et education sexuelle.

Considering the population explosion in Nigeria which is due both to medical advances and traditional beliefs in large families as well as the recent trend of sexual permissiveness which involves the teenagers population, the author of the article considers that sex education is imperative in Nigeria. However, he sees many obstacles standing in the way of general acceptance of sex education. The husband-wife relationship does not encourage free communication on the subject and colonization has removed the traditional forms of sex education through initiation rites and pre-marital counseling by the elders so that young people nowadays rely mostly on peer information or erotic movies and publications. It seems to the author that the only avenue left open is to teach sex education through the school systems. A systematic review of the provisions for sex education in primary and secondary schools as well as teacher's training colleges bring the author to the conclusion that although the sex education curriculum seems comprehensive on paper, they are mere copies of similar American or Canadian programmes with very little attempt at indigenizing them. Furthermore, the syllabus seem to be concentrated on one year instead of being spread out over the school career. The author expresses his conviction that the topic could easily be made acceptable with the right approach and he advocates grounding sex education teaching in the traditional roots of the students.