S. C. Johnson

Effect of antioxidant supplementation on urine and blood markers of oxidative stress during extended moderate-altitude training

OBJECTIVE To investigate the increase in oxidative stress during work at moderate altitudes due to additional energy expenditure, tissue anoxia, and UV light exposure. METHODS Thirty US Marine Corps volunteers were divided into placebo (P) and antioxidant supplement (S) groups and tested for markers of oxidative stress before (t0), at the midpoint of (t1), and after (t2) 14 days of winter training at a moderate altitude (approximately 2700 m). The antioxidant supplement consisted of a daily dose of 20,000 IU beta-carotene, 400 IU vitamin E, 500 mg vitamin C, 100 micrograms selenium, and 30 mg zinc. The following markers of oxidative stress were measured: urine thiobarbituric acid reactive substances (TBARSs), urine hydroxynonenal (HNE), urine 8-hydrodeoxyguanosine (8-OHdG), plasma total peroxyl radical trapping potential (TRAP), and plasma lipid hydroperoxides (LPOs). Urine was collected on a 24-hr basis at t0, t1, and t2; blood samples were collected at t0 and t2. RESULTS P group LPOs increased 30% (p < 0.05) between t0 and t2, whereas S group LPOs did not increase. Both groups exhibited significant increases in urine TBARSs, HNE, and 8-OHdG by t2. Urine TBARSs, HNE, and 8-OHdG increased between t0 and t1 in both groups, with the greater increase in the S group. The conflicting results between the plasma and urine markers of oxidative stress may be due to a time-phase relationship. CONCLUSIONS The results of this study suggest that work in a moderate-altitude cold-weather environment is accompanied by increased oxidative stress, despite relatively high intakes of dietary and supplemental antioxidants.

Behavioral smoking cessation treatment for older chronic smokers.

The benefits of behavioral smoking cessation treatment were examined in 82 chronic smokers 50 years of age and older. Participants were randomized into one of four intervention conditions: (1) behavioral training only, (2) behavioral training and nicotine gum, (3) behavioral training and physical exercise, and (4) physical exercise only. Behavioral training involved 3 months of group treatment, and physical exercise consisted of a 3-month walking program. Quit rates were assessed at program end and at 4, 7, and 12 months postrandomization. At 12 months the proportion quit across groups was respectively 31.8, 36.4, 27.8, and 10.0%. One-year quit data indicated that behavioral training facilitated cessation over the physical exercise only condition.

The effects of aerobic exercise after lumbar microdiscectomy.

Study Design This study determined whether lumbar discectomy patients could endure an aerobic exercise program sufficient to achieve a training effect, and whether any functional advantages were derived. Methods. Trained volunteers (n = 19) were compared with untrained control subjects (n = 18) after a 12-week aerobic and rehabilitation exercise program. Subjects completed a maximal graded exercise test, a hydrostatic weighing test, and a battery of self-report inventories. Results. Using a discriminant analysis, as a post hoc test, maximal oxygen consumption was found to be the factor responsible for the difference between the groups (P < 0.006). Conclusion. Oxygen consumption was more than three times as important as any other single variable in differentiating between the groups.

The effect of aerodynamic handlebars on oxygen consumption while cycling at a constant speed

In this study, the oxygen consumption (VO2) of bicycling was measured at a fixed speed (40 km.h-1), on level terrain, with normal and aerodynamic handlebars using a Douglas bag collection system. Eleven elite (USCF category 1 or 2) men cyclists age 24 to 40 years (mean = 28.5, SD +/- 4.6) performed four consecutive (two with each bar in alternating order) steady state rides at 40 km.h-1 over a 4 km flat course (same direction each trial). Expired gases were collected in a 1501 Douglas bag attached to a following vehicle during the last 45 s (approx. 0.5 km) of each trial. A repeated measures analysis of variance revealed a significant (p < 0.02) handlebar effect. Specifically, VO2 was 2% lower under the aerodynamic handlebar treatment (mean = 4.26, SD +/- 0.36 l.min-1) when compared with that of the normal handlebar treatment (mean = 4.34, SD +/- 0.35 l.min-1). The results of this study demonstrate that the reported aerodynamic advantage of the aerodynamic handlebars produces a small but significant reduction in the VO2 of bicycling at 40 km.h-1.

Necropsy in Suspension

The position of an implanted artificial heart inside a calf was evaluated using a new and innovative method of necropsy. In the past the conventional method of necropsy with the calf on its back or side has failed to reveal the significance of these problems concerning positioning of the artificial heart. Using a new method introduced here, with the calf suspended as if it were standing on its four legs, a better understanding and evaluation of the artificial heart inside the thoracic cavity is possible.It was found that the major cause of distortion of the Kwan-Gett artificial heart from the desired position was the lack of space available due to its large ventro-dorso dimension. A new Jarvik artificial heart with a shorter ventro-dorso diameter was shown, by the new method of autopsy, to solve the problem of distortion (impingement on the great veins).