Alleviating effects of dehydration under no hyperthermia on the immunomodulatory response to the polysaccharide fraction from fu-ling (Poria cocos) in male collegiate wrestlers / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>It is well known that dehydration can impair bodily functions. To evaluate the impact of hydration status under ambient environmental temperature on the immune system, 25 male collegiate wrestlers were recruited to undergo an experimental dehydration program.</p><p><b>METHODS</b>Thirteen subjects had controlled diets with individual energy requirements to prevent body mass loss and restricted water intake to cause 4.52% dehydration; they formed the dehydrated group (DE). These subjects developed a urine specific gravity of about 1.030 in 84 hours. Twelve other subjects had no water restriction and maintained their total body weight comprised the euhydrated group (EU). Peripheral blood monocytes (PBMNC) were isolated after dehydration to perform immune response testing by being incubated with a polysaccharide fraction from fu-ling, Poria cocos (polysaccharide fraction from Poria cocos, PCPS, 1 - 30 £g/L), to prepare a conditioned medium termed conditioned medium of PBMNC stimulated by PCPS (PCPS-MNC-CM). More PCPS (25 µg/L) was needed in the DE group to prepare the PCPS-MNC-CM, which was assayed with a growth inhibitory curve for treated U973 cells.</p><p><b>RESULTS</b>The treated U937 cells, incubated together with PCPS-MNC-CM from the DE group, exhibited a much lower nitroblue tetrazolium (NBT) positive value of (63.7 ± 4.7)%. The concentration of interferon-gamma (IFN-γ), interleukin (IL)-1β and tumor necrosis factor (TNF)-α in PCPS-MNC-CM from subjects after dehydration was much lower than in the CM from the EU group.</p><p><b>CONCLUSION</b>The immune response to PCPS in the DE group was lower than in normally hydrated subjects.</p>

Cycling and Tai Chi Chuan exercises exert greater immunomodulatory effect on surface antigen expression of human hepatitis B virus / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Both athletes with intensive exercise and aged people may have weakened immunity against virus infection. This study aimed to evaluate whether people undergoing aerobic exercises including competitive cyclists with moderate training (CMT) and middle-aged people practicing Tai Chi Chuan (TCC) exercise have higher immunity against hepatitis B virus than age-matched sedentary controls including college students (CSC) and middle-aged people (MSC).</p><p><b>METHODS</b>Human peripheral blood mononuclear cells from competitive cyclists and sedentary controls were stimulated by phytohemagglutinin (PHA) to prepare conditioned medium (MNC-CM) for the assessment of inhibitory effects on hepatitis B surface antigen (HBsAg) expression in human hepatoma Hep3B cells.</p><p><b>RESULTS</b>The inhibitory effects on the relative HBsAg expression of CMT's and TCC's MNC-CM were greater than those of the controls. The CMT's MNC-CM prepared from 5 microg/ml PHA decreased HBsAg expression to 61.5%, whereas that of CSC remained at 83.8%. Similarly, this expression by treatment of TCC group' MNC-CM was 68.4% whereas that of MSC group was 84.3%. The levels of cytokines such as interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), IFN-alpha and interleukin-1beta (IL-1beta) in the MNC-CM from the CMT and TCC groups were greater than those in the controls. Antibody neutralization of CMT's MNC-CM and addition of recombinant cytokines into CSC's MNC-CM indicated that IFN-gamma, TNF-alpha and IFN-alpha had synergistic effects against HBsAg expression. Similar blocking effect was noted in TCC versus MSC groups.</p><p><b>CONCLUSION</b>These results suggest that the immunomodulatory response to suppress HBsAg expression in CMT and TCC with moderate aerobic exercise is greater than that in age-matched sedentary controls.</p>

Decreased anaerobic performance and hormone adaptation after expedition to Peak Lenin / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The change of anaerobic exercise abilities during and after a high-altitude expedition or hypoxic exposure is not well studied. To evaluate the effects of an extreme-altitude expedition on anaerobic performance, the 10-second supramaximal test and endocrine hormones were evaluated before and after an expedition to Peak Lenin.</p><p><b>METHODS</b>Four subjects (3 male and 1 female, age (30.5 +/- 16.5) years) were recruited into the study. Three sets of tests were performed, including a basic test at sea level and 20 days before first arrival at the base camp (3600 m), a middle test done at day after returning from the summit to the base camp and the post test at the 10th day after return to the sea level. Both the supramaximal test, performed by a cycle ergometer, and body composition, performed by bioelectrical impedance analysis, were completed before the basic test and post test. The endocrine hormones including cortisol, growth hormone, testosterone, noradrenaline, adrenaline, dopamine, glucagon and beta-endorphin were measured at all tests.</p><p><b>RESULTS</b>Comparing the conditions before and after the expedition, the body measurement parameters were decreased after the expedition, i.e., body weight (-4.22%, P < 0.05), fat-free mass (-2.09%, P < 0.01) and body fat (-8.95%, P = 0.172). The peak power relative/body weight ratio (PP/BW) was similar ((9.70 +/- 1.97) vs (9.11 +/- 1.80) W/kg, P = 0.093), while mean power/body weight ratio (MP/BW) was reduced significantly after the expedition ((9.14 +/- 1.77) vs (8.33 +/- 1.74) W/kg, P < 0.05). Peak power/fat-free mass (PP/FFM), mean power/fat-free mass (MP/FFM) and fatigue index (FI) were significantly lower after the expedition (PP/FFM: (11.95 +/- 1.71) vs (10.99 +/- 1.59) W/kg, P < 0.05; MP/FFM: (11.26 +/- 1.50) vs (10.04 +/- 1.55) W/kg, P < 0.005; FI (85.55 +/- 4.17)% vs (77.25 +/- 4.40)%, P < 0.05). Hormone assays showed a significant increase of noradrenaline (basic vs middle, P < 0.05) as well as decrease of adrenaline (P < 0.05). Meanwhile, a trend towards an increase in dopamine (basic vs middle) and a decrease of beta-endorphin (basic vs post) were also noted.</p><p><b>CONCLUSIONS</b>These results suggested that an expedition to an extreme altitude may have negative effects on anaerobic performance. It showed that a significant increase of noradrenaline (basic vs middle) as well as decrease of adrenaline after the expedition to Peak Lenin had occurred. The real physiological significance needs to be further investigated.</p>