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The two aims of this study were (i) to compare the effects of prolonged exercise on circulating neutrophil number and muscle myeloperoxidase (MPO) activity between RAG2/gamma c null and immune-competent mice, and (ii) to evaluate the general suitability of the lymphocyte-deficient RAG2/gamma c null strain for use in exercise models of immune regulation. RAG2/gamma c null (male and female) and C57BL/6 (congenic immune-competent, male) mice were assigned to either control (C) or treadmill exercise (EX, 22 m/min, 90 min, 6% grade) groups. EX mice were killed immediately (EX0) or 24 h (EX24) after exercise. RAG2/gamma c null males had significantly (P0.05) fewer circulating CD45+ cells and higher %CD45+ neutrophils than did C57BL/6 males, independent of exercise. A significant interaction was observed for the effects of exercise and gender on %CD45+ neutrophils in the blood. At EX24, gastrocnemius (Gastroc) MPO significantly increased in EX mice. Gastroc MPO activity was 44% and 35% higher in RAG2/gamma c null vs. C57BL/6 males, and in female vs. male RAG2/gamma c null mice, respectively. Heart MPO activity did not differ between strains or among treatments. We concluded that the Rag2/gamma c null strain is a suitable model for future investigations on immune regulation following acute exercise stress.

Previous studies in our laboratory indicate that alcohol consumption suppresses the metastasis of B16BL6 melanoma, whereas the cytolytic activity of natural killer (NK) cells is decreased in female C57BL/6 mice given 20% w/v alcohol in their drinking water. In the present study, we further evaluated the involvement of NK cells and alcohol consumption in the cytolytic activity of NK cells, the surface expression of NK phenotypic markers, and metastasis of B16BL6 melanoma in C57BL/6 beige (bgJ/bgJ) mutant mice, which possess inherently low NK-cell cytolytic activity.Beige and control (bgJ/+) mice were given either water or 20% w/v of alcohol in drinking water for 6 1/2 to 7 weeks before assay for cytolytic activity, surface marker expression, and inoculation with B16BL6 melanoma intravenously or into the pinna of the ear.NK cytolytic activity was suppressed in beige mice, and alcohol consumption did not modulate further the cytolytic activity. Beige mice had a lower percentage of NK cells in the peripheral blood and spleen than control mice. Peripheral blood lymphocytes from beige mice also exhibited a reduced percentage of CD4+ T lymphocytes. Alcohol consumption similarly reduced the percentages of NK1.1- and LGL-1-expressing lymphocytes in the peripheral blood and spleen and reduced the percentage of CD8+ T lymphocytes in the peripheral blood in both control and beige mice. Tumor lung colonization was increased in beige mice relative to control mice after intravenous inoculation of B16BL6 melanoma. The increase was more pronounced in water-drinking beige mice than in control mice irrespective of alcohol consumption. Tumor lung colonization was significantly decreased (p0.05) by alcohol consumption in one experiment and partially decreased (p = 0.07) in the other. Mice that were inoculated into the pinna of the ear also exhibited a blunted antimetastatic response to alcohol consumption.These data suggest that the presence of the beige mutation diminishes the antimetastatic effect of alcohol consumption and that there is no interaction between alcohol consumption and NK-cell activity in the modulation of lung metastasis of B16BL6 melanoma cells.

This study was designed to examine the relationship between endurance training volume and natural killer cell (NK) cytolytic activity. We hypothesized that a dose dependent relationship exists between forced treadmill training volume and training induced increases in NK cell cytolytic activity.female, Swiss Webster mice were assigned to treadmill control (TC) or treadmill trained groups (n = 10 per group). Trained mice ran at 12 m per min. (8 degrees grade) for: 15 (EX15), 30 (EX30), or 60 minutes (EX60) per day, five days per week for 11 weeks. Splenic NK cell activity was expressed as median lytic unit (LU), median LU per asialo GM1 (AsGM1+) cell, and median LU per spleen.Median NK activity was not significantly increased by training volume. A trend toward greater median LU per AsGM1+ cell was observed in EX30 group versus TC (p = 0.1). Training volumes less than or greater than this level produced smaller increases in NK cytolytic activity.These data provide preliminary evidence indicating that training induced increases in splenic NK cell cytolytic activity do not exhibit a dose dependent relationship with treadmill training volume.

Collegiate varsity oarswomen and coxswain (N = 11) completed maximal aerobic exercise tests on a treadmill, a rowing ergometer, and a simulated climbing machine. Successful completion of each test was evidenced by a plateau in oxygen consumption in response to increasing work rates. VO2max (l.min-1), and minute ventilation (VE, l.min-1) at VO2max were significantly greater (P0.05) during simulated climbing compared to treadmill running and rowing ergometry. Maximal heart rate (beats.min-1) was significantly greater (P0.05) during climbing and running than during rowing. Findings indicate that progressive, incremental, whole-body climbing exercise elicits significantly greater VO2max values for collegiate oarswomen and coxswain than does graded treadmill running or progressive rowing ergometry.

The aero-cycling posture has become increasingly popular among cyclists. Because of the potential for altered lung mechanics in the aero-cycling posture, the ventilatory and gas exchange profiles of 10 moderately trained males (31.1 +/- 6.3 yr, mean +/- SD) exercising on a cycle ergometer in the upright posture (UC) and aero-cycling (AC) posture were studied. Exercise consisted of 3-min work stages with 50-W incremental changes until volitional exhaustion. Ventilatory and gas exchange responses to exercise were averaged each minute. Maximal oxygen consumption (54.3 +/- 6.3 vs 53.4 +/- 6.9 ml.kg-1.min-1) in the UC and AC were not significantly different. Maximal values for ventilation (132.5 +/- 32.3 vs 128.0 +/- 28.7 l.min-1), tidal volume (2.7 +/- 0.5 vs 2.6 +/- 0.3 1.br-1), breathing frequency (50.0 +/- 8.0 vs 47.0 +/- 5.0 br.min-1), and submaximal ventilatory and heart rate responses in the UC were not significantly different compared with the AC. No significant difference existed between postures for mean inspiratory flow and inspiratory duty cycle at comparable submaximal power outputs. These results indicate that at absolute power outputs, ventilatory responses, as determined by respiratory pattern and timing, and metabolic cost, were similar in the UC and AC. Thus, the AC does not impair physiologic responses to high intensity exercise.

Collegiate varsity oarswomen and coxswain (N = 11) completed maximal aerobic exercise tests on a treadmill, a rowing ergometer, and a simulated climbing machine. Successful completion of each test was evidenced by a plateau in oxygen consumption in response to increasing work rates. VO2max (l.min-1), and minute ventilation (VE, l.min-1) at VO2max were significantly greater (P < 0.05) during simulated climbing compared to treadmill running and rowing ergometry. Maximal heart rate (beats.min-1) was significantly greater (P < 0.05) during climbing and running than during rowing. Findings indicate that progressive, incremental, whole-body climbing exercise elicits significantly greater VO2max values for collegiate oarswomen and coxswain than does graded treadmill running or progressive rowing ergometry.

Lewis rats were used to determine the encephalitogenic activity of myelin basic protein of different species and of 45-residue fragments of basic protein. Basic protein from guinea pigs was more active than that from rats, and the fragments from the two species showed the same order of activity. Bovine basic protein was the least active of the intact proteins, and the respective fragment was inactive. Studies of serum-binding capacity did not support the hypothesis that blocking antibody played a role in this biological variation, whereas consideration of the amino acid sequences of the three fragments suggested that differences in primary structure, operating either at the sensitization or the effector phase of the immune response, could account for the variation.