Reduction of the spin-label TEMPONE by ubiquinol in the electron transport chain of intact rabbit spermatozoa.

When the hydrophilic spin label TEMPONE (deuterated 2,2,6,6-tetramethylpiperidine-N-oxyl) was incubated with intact rabbit spermatozoa at concentrations greater than 0.3 X 10(9) cells/ml, the electron spin resonance signal height decreased with time. This loss of signal amplitude was reversed by the oxidizing reagent potassium dichromate, indicating that the signal loss was due to a reduction of the paramagnetic nitroxide species to the nonparamagnetic hydroxylamine. Using inhibitors that act on the respiratory chain, we observed that, relative to controls, the rate of TEMPONE reduction was decreased in the presence of rotenone, but increased in the presence of antimycin A and potassium cyanide (KCN). Parallel studies measuring oxygen consumption showed decreases with all three inhibitors. We interpret these observations to mean that TEMPONE is reduced by ubiquinol in the respiratory chain. Supporting this conclusion is the observation that the midpoint potential of TEMPONE was determined by be +48mV, which is close to the midpoint potential of +40 mV for the ubiquinone/ubiquinol couple. Furthermore, in a cell-free test system, ubiquinol reduced TEMPONE, but ubiquinone, NADH, and succinate did not.

The University of Akron study on air pollution and human health effects I. Methodology, baseline data, and aerometrics.

This study determined the health effects of ambient air pollutants in two grade school populations in Akron, Ohio. One school is adjacent to industry and has elevated levels of sulfur dioxide (SO2) and moderate levels of nitrogen dioxide (NO2), while the other school is 4 km east and unpolluted. This study was designed in this manner for two purposes: (1) to identify and monitor ambient levels of air pollutants in an area proximal to the grade school so that the levels could be accurately assessed, and (2) to determine baseline pulmonary function values and questionnaire responses from the parents indicating any acute and/or chronic respiratory problem in the child. Ninety-five percent of the children enrolled in this study liver within 2 km of the schools and aerometric stations, thus providing for careful control in the study design. The results of this study indicate that SO2 and NO2 levels are significantly higher in the school adjacent to industry. Although pulmonary function data were not significantly different between schools, the frequency of questionnaire responses to acute and chronic pulmonary problems was greater in the children at the school adjacent to industry. The data tend to indicate early pulmonary effects of air pollution in children living adjacent to industry and exposed to elevated levels of SO2 and NO2. We suggest that additional longitudinal work that carefully monitors total suspended particulates, NO2, SO2, and health data should be conducted to confirm these results.

Oral contraceptives and exercise.

PIP: A laboratory study was undertaken with volunteer females (aged 20-25) to determine the effect of OCs (oral contraceptives) on hematologic and metabolic variables during exercise. 5 of the women studied were naturally cycling and 7 were taking OCs. The women worked at 2 workloads on a bicycle ergometer at 50% and 90% of their maximal aerobic capacity during 3 different phases of their menstrual cycle. There was no better time of the month for doing the 50% or the 90% workload in either group. Heartrate for the OC group was significantly higher at the 50% maximal capacity. Results of the test indicate tha women on OCs have somewhat reduced cardiac efficiency and are ventilating more to carry out a given amount of work when compared to women who are naturally cycling. Possible explanations for the higher heart rate are put forward. The main limitation of the study is that the subject numbers involved are small and the number of cycles studied is also small.^ieng