AIM:To investigate the effect of repeated lower +Gzexposure on liver injury induced by high +Gz exposure in rats.METHODS:Sixty male Wister rats were randomly divided into a blank control group,a low G preconditioning ...AIM:To investigate the effect of repeated lower +Gzexposure on liver injury induced by high +Gz exposure in rats.METHODS:Sixty male Wister rats were randomly divided into a blank control group,a low G preconditioning group(LG)(exposed to +4 Gz/5 min per day for 3 d before +10 Gz/5 min exposure),and a +10 Gz/5 min group(10G)(n = 20 in each group).Blood specimens and liver tissue were harvested at 0 h and 6 h after +10 Gz/5 min exposure.Liver function was analyzed by measuring serum alanine transaminase(ALT) and aspartate aminotransferase(AST) levels,and liver injury was further assessed by histopathological observation.Malondialdehyde(MDA),superoxide dismutase(SOD) and Na+-K+-ATPase were determined in hepatic tissue.RESULTS:The group LG had lower ALT,AST,and MDA values at 0 h after exposure than those in group 10 G.SOD values and Na+-K+-ATPase activity in the LG group were higher than in group 10 G 0 h post-exposure.Hepatocyte injury was significantly less in group LG than in group 10 G on histopathological evaluation.CONCLUSION:It is suggested that repeated low +Gz exposure shows a protective effect on liver injury induced by high +Gz exposure in rats.展开更多
Background:Technological advancements in modern military and acrobatic jet planes have resulted in extraordinary psychophysiological loads being exerted upon flying personnel,including inducing neck and back pain.The ...Background:Technological advancements in modern military and acrobatic jet planes have resulted in extraordinary psychophysiological loads being exerted upon flying personnel,including inducing neck and back pain.The purpose of this study was to examine the effects of 12 weeks of functional strength training on 1)the volume and strength of the neck and shoulder muscles and 2)muscular activity upon exposure to helmets of different masses and elevated Gz forces in a long-arm centrifuge in high-performance aircraft personnel.Methods:Eighteen participants underwent 12 weeks of functional strength training(n=12)or the control protocol(n=6)without additional strength training.Pre-and post-intervention tests included evaluations of isometric strength of the head extensor muscles,flexion,and lateral flexion and rotation,as well as magnetic resonance imaging(MRI)to measure the volume of the m.sternocleidomastoideus,m.trapezius,and deep neck muscles.Furthermore,during a long-arm centrifuge(+1.4 and+3Gz)protocol,the muscular activity levels of the m.sternocleidomastoideus,m.trapezius and m.erector spinae muscles were assessed without a flight helmet,with a helmet,and with a helmet and night vision goggles.Each participant’s perception of muscular strain was noted immediately after the long-arm centrifuge protocol.Results:The maximal isometric strength in all exercises and muscle volumes increased in the training group but not the control group(P<0.05).Relative muscle activity(%MVC)with a helmet decreased after the intervention in the training but not the control group(P=0.01).Relative muscle activity while wearing a helmet and night vision goggles was higher after intervention in the control group than in the training group(P<0.01).The perceived muscular strain of the neck muscles induced by the long-arm centrifuge did not differ between the groups.Conclusions:Twelve weeks of functional strength training improves the maximal isometric strength and volume of neck and shoulder muscles and leads to lower relative muscle acti展开更多
随着高性能战斗机和航天宇宙飞船的应用,高空环境对飞行员的损伤给他们带来了严峻的挑战.其中,正加速度(+Gz)暴露后消化性溃疡的发病率和复发率在进一步提高.溃疡复发是现代医学的难点,与溃疡愈合质量(quality of ulcer healing,QOUH)...随着高性能战斗机和航天宇宙飞船的应用,高空环境对飞行员的损伤给他们带来了严峻的挑战.其中,正加速度(+Gz)暴露后消化性溃疡的发病率和复发率在进一步提高.溃疡复发是现代医学的难点,与溃疡愈合质量(quality of ulcer healing,QOUH)密切相关,提高QOUH被认为是对消化性溃疡认识的第3次飞跃,已成为目前航天航空医学的主要研究热点.本文从胃溃疡动物模型的建立、溃疡愈合质量的评价、+Gz对溃疡愈合质量影响的相关因素、实际应用等方面,对+Gz对大鼠实验性QOUH影响的研究进展进行综述,旨在促进相关的应用基础研究和提高针对高+Gz损伤的胃肠防护,进而增强飞行员的整体抗+Gz能力,提高飞行的安全性.展开更多
文摘AIM:To investigate the effect of repeated lower +Gzexposure on liver injury induced by high +Gz exposure in rats.METHODS:Sixty male Wister rats were randomly divided into a blank control group,a low G preconditioning group(LG)(exposed to +4 Gz/5 min per day for 3 d before +10 Gz/5 min exposure),and a +10 Gz/5 min group(10G)(n = 20 in each group).Blood specimens and liver tissue were harvested at 0 h and 6 h after +10 Gz/5 min exposure.Liver function was analyzed by measuring serum alanine transaminase(ALT) and aspartate aminotransferase(AST) levels,and liver injury was further assessed by histopathological observation.Malondialdehyde(MDA),superoxide dismutase(SOD) and Na+-K+-ATPase were determined in hepatic tissue.RESULTS:The group LG had lower ALT,AST,and MDA values at 0 h after exposure than those in group 10 G.SOD values and Na+-K+-ATPase activity in the LG group were higher than in group 10 G 0 h post-exposure.Hepatocyte injury was significantly less in group LG than in group 10 G on histopathological evaluation.CONCLUSION:It is suggested that repeated low +Gz exposure shows a protective effect on liver injury induced by high +Gz exposure in rats.
文摘Background:Technological advancements in modern military and acrobatic jet planes have resulted in extraordinary psychophysiological loads being exerted upon flying personnel,including inducing neck and back pain.The purpose of this study was to examine the effects of 12 weeks of functional strength training on 1)the volume and strength of the neck and shoulder muscles and 2)muscular activity upon exposure to helmets of different masses and elevated Gz forces in a long-arm centrifuge in high-performance aircraft personnel.Methods:Eighteen participants underwent 12 weeks of functional strength training(n=12)or the control protocol(n=6)without additional strength training.Pre-and post-intervention tests included evaluations of isometric strength of the head extensor muscles,flexion,and lateral flexion and rotation,as well as magnetic resonance imaging(MRI)to measure the volume of the m.sternocleidomastoideus,m.trapezius,and deep neck muscles.Furthermore,during a long-arm centrifuge(+1.4 and+3Gz)protocol,the muscular activity levels of the m.sternocleidomastoideus,m.trapezius and m.erector spinae muscles were assessed without a flight helmet,with a helmet,and with a helmet and night vision goggles.Each participant’s perception of muscular strain was noted immediately after the long-arm centrifuge protocol.Results:The maximal isometric strength in all exercises and muscle volumes increased in the training group but not the control group(P<0.05).Relative muscle activity(%MVC)with a helmet decreased after the intervention in the training but not the control group(P=0.01).Relative muscle activity while wearing a helmet and night vision goggles was higher after intervention in the control group than in the training group(P<0.01).The perceived muscular strain of the neck muscles induced by the long-arm centrifuge did not differ between the groups.Conclusions:Twelve weeks of functional strength training improves the maximal isometric strength and volume of neck and shoulder muscles and leads to lower relative muscle acti
文摘随着高性能战斗机和航天宇宙飞船的应用,高空环境对飞行员的损伤给他们带来了严峻的挑战.其中,正加速度(+Gz)暴露后消化性溃疡的发病率和复发率在进一步提高.溃疡复发是现代医学的难点,与溃疡愈合质量(quality of ulcer healing,QOUH)密切相关,提高QOUH被认为是对消化性溃疡认识的第3次飞跃,已成为目前航天航空医学的主要研究热点.本文从胃溃疡动物模型的建立、溃疡愈合质量的评价、+Gz对溃疡愈合质量影响的相关因素、实际应用等方面,对+Gz对大鼠实验性QOUH影响的研究进展进行综述,旨在促进相关的应用基础研究和提高针对高+Gz损伤的胃肠防护,进而增强飞行员的整体抗+Gz能力,提高飞行的安全性.
