Effect of a 30-day period of hypokinesia on various physiologic and biochemical indicators during maximal physical load

Exercise tolerance of test subjects who remained bed rested (Group A) and who exercised while being supine (Group B) was measured before and after 30-day head-down tilt (-8 degrees). Special attention was given to the parameters that characterize energy supply of working muscles. The data obtained after 30-day bed rest did not reveal any changes in the Group B subjects and showed the following changes in the Group A subjects: maximum oxygen consumption decreased by 10.1% (p less than 0.05), the time within which the anaerobic metabolism threshold was attained decreased by 17.2% (p less than 0.05), and lactate concentration at the workload end decreased by 24.7%, while the pyruvate concentration and the lactate/pyruvate ratio remained unchanged. The results indicate that prolonged aerobic workload after 30-day bed rest seems to be limited by functional changes in oxygen transport rather than by the factors associated with changes in energy supply of working muscles.     

Cytokine responses at high altitude: effects of exercise and antioxidants at 4300 m

PURPOSE: This study tested the hypothesis that antioxidant supplementation would attenuate plasma cytokine (IL-6, tumor necrosis factor (TNF)-alpha), and C-reactive protein (CRP) concentrations at rest and in response to exercise at 4300-m elevation. METHODS: A total of 17 recreationally trained men were matched and assigned to an antioxidant (N = 9) or placebo (N = 8) group in a double-blinded fashion. At sea level (SL), energy expenditure was controlled and subjects were weight stable. Then, 3 wk before and throughout high altitude (HA), an antioxidant supplement (10,000 IU beta-carotene, 200 IU alpha-tocopherol acetate, 250 mg ascorbic acid, 50 microg selenium, 15 mg zinc) or placebo was given twice daily. At HA, energy expenditure increased approximately 750 kcal.d(-1) and energy intake decreased approximately 550 kcal.d, resulting in a caloric deficit of approximately 1200-1500 kcal.d(-1). At SL and HA day 1 (HA1) and day HA13, subjects exercised at 55% of VO2peak until they expended approximately 1500 kcal. Blood samples were taken at rest, end of exercise, and 2, 4, and 20 h after exercise. RESULTS: No differences were seen between groups in plasma IL-6, CRP, or TNF-alpha at rest or in response to exercise. For both groups, plasma IL-6 concentration was significantly higher at the end of exercise, 2, 4, and 20 h after exercise at HA1 compared with SL and HA13. Plasma CRP concentration was significantly elevated 20 h postexercise for both groups on HA1 compared to SL and HA13. TNF-alpha did not differ at rest or in response to exercise. CONCLUSION: Plasma IL-6 and CRP concentrations were elevated following exercise at high altitude on day 1, and antioxidant supplementation did not attenuate the rise in plasma IL-6 and CRP concentrations associated with hypoxia, exercise, and caloric deficit.     

Lipid metabolic indices in man during head-down tilt hypokinesia and their correction

Twenty one test subjects exposed to head-down tilt for 120 days were subdivided to four groups: Group 1--nine subjects used as controls, Group 2--three bed rested subjects who performed regular exercises, Group 3--four bed rested subjects who were given selected drugs, including Vitamin F-99 that influenced lipid metabolism, and Group 4--four bed rested subjects who performed regular exercises and received Vitamin F-99. At different stages of bed rest and recovery the content of lipoprotein fractions and lipids of different classes in serum was measured by thin-layer chromatography. The concentration of cholesterol in biliary lipids was determined. In Group 1 and 2 subjects bed rest led to a drastic and significant increase of cholesterol esters in blood, a decrease of phospholipids, variations of triglycerides and non-esterified fatty acids, and a lower percentage content of alpha-lipoproteins. The use of Vitamin F-99 produced positive changes in the above parameters of lipid metabolism (it normalized the level of cholesterol and phospholipids). In Group 4 subjects the effect of exercise combined with drugs was most distinct.     

高压氧干预对抗低氧效果的观察

目的探讨高压氧干预对初入高海拔地区青年的作用。方法将42名受试者随机分为A、B、C三组,每组14人。于进驻高原前2 d对A组在海拔1400 m进行高压氧干预,每天1次共2次;于第3天三组青年同时乘汽车历时2 d到达海拔3700 m地区休整2 d,同时对B组进行高压氧干预(方法同A组);C组为对照组。于第7天三组青年同时乘汽车历时1 d到达海拔5200 m某边防哨卡。对三组进驻哨卡第2、4、6天的急性高原反应症状分度评分,同时检测心率(HR)和血氧饱和度(SaO2)。结果A组及B组较C组分值降低、HR减慢、SaO2增高,差异均有统计学意义(P<0.05)。结论高压氧干预可改善高原低氧血症,降低急性高原反应的发病率。     

Orthostatic tolerance and hormonal changes in women during 120 days of head-down bed rest

BACKGROUND: Women will be included as mission specialists in the upcoming International Space Station program. This paper describes the changes in volume-regulating hormones and determines the degree of degradation in orthostatic tolerance in a group of women after 120 d of bed rest. The aim of this study was to test a countermeasure program to be used by women during long-duration spaceflights. METHODS: For 120 d of -6 degrees head-down bed rest (HDBR), eight healthy women were assigned either to a no-countermeasure (No-CM, n = 4), or to a countermeasure (CM, n = 4) group. In the countermeasure group, exercise began after 2 wk, pharmacological agents were given during the 1st and 3rd mo, and the "Centaur" suit was worn on the last day of bed rest and during the day time for several days after bed rest. Diet supplements were taken during the 1st and 4th mo of HDBR. Tilt tests were run before and after HDBR. RESULTS: After the HDBR, none of the CM subjects, had pre-syncopal or syncopal symptoms during tilt tests: BP was well maintained in the CM group, while heart rate and BP changed in the No-CM group. In plasma, atrial natriuretic peptide (ANP) increased in both groups and remained high throughout HDBR, while aldosterone increased and remained elevated in the No-CM group. Natriuresis was decreased during HDBR. CONCLUSION: The CM protocols used during this study were efficient and prevented orthostatic intolerance for the four CM subjects. It would be necessary to obtain more data regarding this set of CM protocols on female subjects to lead to statistical and formal conclusions.     

Paramecium test for toxic substances in the blood of humans exposed to conditions simulating weightlessness

The Paramecium test was for the first time used to measure the build-up of toxic substances in the healthy man exposed to simulated weightlessness. The most distinct changes were seen on bed rest days 3 and 7-8 in all test subjects (41 subjects). After bed rest day 8 the parameter reached a plateau, the toxicity level stopped to increase, but the Paramecium test time remained shorter than normal. It can therefore be suggested that the prognosis of any disease that may develop in this situation will be worse. In view of this it is important to improve the prophylaxis and treatment of endogenous and exogenous intoxications during space flight and to provide active detoxication based on the purification of biological fluids by sorption.     

HA1077对骨髓间质干细胞促愈作用的影响

目的 探讨HA1077对骨髓间质干细胞(bone mesenchymal stem cells,BMSCs)促愈作用的影响及其机制. 方法 (1)体外实验:体外分离培养大鼠BMSCs,随机分为正常对照组、诱导组和HA1077组.对照组加入DMEIM完全培养液;诱导组:70%DMEM完全培养液+30%大鼠成纤维细胞上清液+含8 μg/L表皮细胞生长因子(EGF)的培养液;HA1077组:在诱导组培养液基础上加入终浓度为10 μmol/L的HA1077.取培养7 d的细胞,流式细胞检测CK19表达,细胞周期和核增殖抗原(PCNA)表达.(2)在体实验:按前述方法 制备兔BMSCs.取新西兰大耳白兔8只,在背部制备6个直径为3 cm的圆形皮肤缺损(每侧各3个),深至皮下.创面随机分为空白对照组(A组):创面应用等渗盐水;EGF对照组(B组):创面外用EGF,50 U/cm2;BMSCs治疗组(C组):除用EGF外,创面注射BMSCs细胞悬液1 ml,2×106/ml;BMSCs+HA1077治疗组(D组):除应用C组措施外,创面注射0.5 ml HA1077,浓度为20 μmol/L.伤后3,7,14 d计算愈合指数(WCI). 结果 (1)体外实验:诱导组CK19的阳性率为(11.13±2.14)%,HA1077组为(40.31±0.81)%,明显高于诱导组(P<0.01).HA1077组PCNA阳性率明显高于诱导组,细胞周期分析显示S期细胞数量最多.(2)在体实验:D组伤后14 d的创面愈合指数为86.20±1.92,效果明显好于B组、C组和对照组. 结论 HA1077可以促进BMSCs细胞表达PCNA进入S期,进而分化表达CK19;在体表联合应用HA1077和BMSCs,可以明显促进创面愈合.     

Visualization of abdominal arteries by super-high-flow venous injection using multidetector helical CT

The purpose in this study was to compare the ratio of visualization of upper abdominal arteries using MDHCT between the super-high-flow injection method (Group A) and the conventional injection method (Group B). The subjects ects were 200 patients who were randomly divided into Group A (100 patients) and Group B (100 patients). In Group A, visualization of the large arteries, including the CE, SMA, HA and LGA, was possible at a rate exceeding 96%, and that of the small arteries, including the DPA, SPDA, RGA and Cyst A, was more than 79%. Visualization of upper abdominal arteries was markedly improved by the super high flow injection technique.     

Cancellous bone structure of iliac crest biopsies following 370 days of head-down bed rest

INTRODUCTION: Static bone histomorphometry was applied to existing iliac bone sections originating from a 370-d 5 degrees head-down bed rest experiment. This bed rest experiment is the longest ever to have been conducted. We hypothesized that bed rest would decrease cancellous bone volume fraction and that this effect would be reversed by countermeasures. METHODS: Eight healthy male subjects underwent 370 d of 5 degrees head-down bed rest. Three subjects were treated with bisphosphonate (Xidifon, potassium salt of ethane-1-hydroxy-1-disphosphonate, EHDP) combined with an exercise regimen (1-2 h x d(-1)) for the entire study period. Five subjects underwent 120 d of bed rest without countermeasures followed by 250 d of bed rest with the exercise regimen. Transiliac bone biopsies were obtained either at baseline and day 366, or at baseline, day 116, and day 366 at alternating sides of the ileum. Static histomorphometry was performed using a computerized method. RESULTS: The 120 d of head-down bed rest without countermeasures resulted in decreased bone volume fraction BV/TV (-6.3%, p = 0.046) and trabecular number (Tb.N; -10.2%, p = 0.080) and increased trabecular separation (Tb.Sp; 14.7%, p = 0.020), whereas the 250 d of subsequent head-down bed rest with exercise treatment prevented further significant deterioration of the histomorphometric measures. DISCUSSION: The 120 d of 5 degrees head-down bed rest without countermeasures induced significant deterioration of iliac crest cancellous bone histomorphometric properties. On average, the countermeasures consisting of either bisphosphonate and exercise, or exercise alone were able to either prevent or stop immobilization-induced changes of the iliac cancellous bone structure.     

Effects of 1-week head-down tilt bed rest on bone formation and the calcium endocrine system.

To understand the potential early responses of human bone and the calcium endocrine system to spaceflight, we studied 8 healthy men, aged 35-44 years before, during, and after bed rest in a -6 degrees head-down tilt model for microgravity. Based on a novel single-dose labeling schedule, average rates of bone formation in the iliac crest were reduced in 6, unchanged in 1, and increased in 1 following the bed rest period. The decrease was greatest for subjects whose daily walking miles were highest (r = -0.762, p less than 0.05, n = 7). Before a measurable increase in ionized serum calcium the sixth bed rest day, there was increased excretion of urinary calcium and sodium, evident the first 2 bed-rest days and parallel for the entire week (r = 0.92, p less than 0.001). Reduced excretion of phosphorus and 3', 5' cyclic adenosine monophosphate on the first and second bed rest days was followed by an increase in serum phosphorus by the sixth bed rest day. Depressed serum concentrations of parathyroid hormone and 1,25-dihydroxyvitamin D were manifest by the sixth and seventh bed rest days. The similarity of the response of bone and the calcium endocrine system of healthy men after only 7 days to results of longer term bed rest studies emphasizes the responsiveness of the adult human skeleton to biomechanical stimuli induced by changes in activity and/or position.     

卧床中及卧床后头高位倾斜对心率及血压变异谱的变化

观察了男性青年２１ｄ头低位６°卧床过程中以及卧床前、后７５°头高位倾斜（ＨＵＴ）时心率变异（ＨＲＶ）与动脉收缩压变异（ＳＢＰＶ）谱变化。卧床期间，完成者ＨＲＶ和ＳＢＰＶ谱的低，高频谱峰功率（ＬＦ和ＨＦ）均显著减小，ＨＲＶ谱低，高频谱峰功率比值（ＬＦ：ＨＦＨＲＶ）在卧床第１６ｄ有增大趋势，未完成者的相应谱指标有类似变化趋向，在卧床后ＨＵＴ初始６ｍｉｎ，所有被试者心率显著快于卧床前ＨＵＴ时相应值，而Ｌ     

椎体成形术治疗不愈合的胸腰椎陈旧性骨折疗效分析

目的评价靶向穿刺椎体成形术治疗不愈合的胸腰椎陈旧性骨折的疗效。方法 2013年8月~2014年6月,笔者将32例不愈合的陈旧性椎体骨折患者(男性13例,女性19例;年龄63~82岁,平均73.6岁)分为两组:A组14例,为卧床非手术治疗,B组18例,行靶向穿刺椎体成形术治疗。分别测量并比较两组患者治疗前1d、治疗后1d,1个月及1年病椎前缘压缩率,同时行疼痛视觉模拟评分(VAS)和Oswestry功能障碍指数(ODI)评价治疗效果。结果靶向穿刺椎体成形手术组患者疗效优于非手术治疗组患者,术后椎体前缘压缩率较术前有明显改善,差异有统计学意义(P0.05)。手术组患者的术后VAS和ODI评分优于非手术治疗组,两者差异有统计学意义(P0.05)。结论对于不愈合的陈旧性椎体骨折,通过定向穿刺,在骨折部位注射骨水泥,增强了骨折椎体的稳定性,明显缓解了患者的疼痛,改善了患者的生活质量。     

Changes in body fluid compartments during a 28-day bed rest

The extravascular fluid responses to real or simulated space-flight are not well-documented. In this study serial isotope measurements were used to obtain measurements of the body fluid responses of 10 22-29-year-old men during 28 d of simulated microgravity (bed rest). The subjects were maintained on a controlled metabolic diet for 7 d before the study, during 14 d of ambulatory control, 28 d of horizontal bed rest, and 14 d of ambulant recovery. Fluid compartments were measured on control days 1 and 9, bed rest days 2, 14, and 28, and recovery days 7 and 14. By day 2 of bed rest, plasma volume (PV) and extra-cellular volume (ECV) decreased significantly by an average 209 and 533 ml, respectively. Red cell volume (RCV) and total body water (TBW) decreased more slowly, with average losses of 128 and 1,316 ml, respectively, after 28 d of bed rest. Early in the bed rest, TBW loss was mostly from the ECV. Thereafter, the TBW deficit was derived from the intracellular compartment, which decreased an average of 838 ml after 28 d. These results suggest losses from all fluid compartments during bed rest, with no evidence of restoration of ECV after 1-2 weeks.     

地衣芽孢杆菌联合肠宁舒颗粒治疗肠易激综合征临床疗效分析

目的探讨地衣芽孢杆菌联合肠宁舒颗粒治疗肠易激综合征的临床疗效。方法选择2015年1月至2016年1月收治的腹泻型肠易激综合征患者160例,采用数字表法随机分为联合治疗组(A组)与地衣芽孢杆菌治疗组(B组)。B组口服地衣芽孢杆菌治疗,0.5 g/次,3次/d;A组在地衣芽孢杆菌治疗同时,联合肠宁舒颗粒治疗,5 g/次,3次/d。两组患者疗程均为4周,评价其临床疗效。结果 A组与B组总有效率分别为77.5%、47.5%,A组临床疗效显著优于B组,差异有统计学意义(P<0.05);A组患者腹痛时间、腹痛频率、排便性状异常、腹胀症状缓解的疗效均明显优于B组,差异有统计学意义(P<0.05)。结论地衣芽孢杆菌联合肠宁舒颗粒治疗肠易激综合征的临床疗效显著,值得临床上应用与推广。     

Central blood circulation in the healthy human being during 7 days' head-down tilt hypokinesia

The effect of 7-day head-down tilt (-15 degrees) and lower body negative pressure on circulation and oxidative metabolism was investigated on 13 healthy male test subjects. For 7-10 days they had Swan-Ganz catheters implanted in the pulmonary artery and a special cannula in the radial artery. The most marked changes were seen in the pulmonary artery pressure (PAP) and central venous pressure (CVP) that varied in a phase-like manner. By the 7th hour of bed rest the PAP increased significantly; this was followed by increases in the total lung resistance and the right ventricle function, as well as by a slight decrease of renin and aldosterone. Beginning with bed rest days 2 or 3 the PAP and CVP declined and remained lowered, as compared to the pretest level, till the end of bed rest. The responses to LBNP tests changed by bed rest day 2. Possible mechanisms of the above changes at rest and during LBNP tests are discussed.     

Use of the ferrocerone test for measuring iron reserves in different types of daily activities

A test using an iron containing agent, i.e. ferrocerone, was developed to measure iron reserves in the body. After breakfast the subject took a ferrocerone tablet (0.3 g) containing 0.04 g iron. Iron content was measured in 24 hour urine samples with the aid of bathophenanthroline++. Iron excretion was assessed in 24 ambulatory test subjects, aged 18-21 years. Two basic types differing in the excretion rate in different times of the day. After testing the renal excretion rate of the agent in healthy people was 20.8 +/- 0.7 mg. Iron reserves during head-down tilt tests of various duration were estimated in 20 test subjects, 6 of whom participated in a 50-day study (-6 degrees) and 14 in a 120-day study (-4.5 degrees). Iron utilization was highest on readaptation day 13 (in the 50-day study) and on bed rest days 65-75 (in the 120-day study). Increase in iron requirements coincided in time with the period of hemoglobin recovery.     

Effect of lower body negative pressure against orthostatic intolerance induced by 21 days head-down tilt bed rest

BACKGROUND: Exposure to actual or simulated weightlessness is known to induce orthostatic intolerance in humans. Many different methods have been suggested to counteract orthostatic hypotension. The repetitive or prolonged application of lower body negative pressure (LBNP) has shown beneficial effects to counter orthostatic intolerance, but devoting so much time to countermeasures is not compatible with space mission objectives or costs. The purpose of the present study was to assess the effects of brief LBNP sessions against orthostatic intolerance during a 21-d head-down tilt (HDT) bed rest. METHODS: There were 12 healthy male volunteers who were exposed to -6 degrees HDT bed rest for 21 d. Six subjects received -30 mm Hg LBNP sessions for 1 h x d(-1) from day 15 to day 21 of the HDT, and six others served as control. Orthostatic tolerance was assessed by means of standard tilt test. RESULTS: Before HDT, all the subjects in the two groups completed the tilt tests. After 21 d of HDT, five subjects of the control group and one subject of the LBNP group could not complete the tilt test due to presyncopal or syncopal symptoms. The mean upright time in the control group 13.0 +/- 4.0 min) was significantly shorter (p < 0.05) than that in the LBNP group (19.0 +/- 2.2 min). Body weight decreased significantly in the control group during HDT, while increasing significantly on day 21 of HDT in the LBNP group. Urine volume increased on days 15-21 of HDT in the control group, but remained unchanged throughout HDT in the LBNP group. A significant decrease in cardiac output and cardiac index, and a significant increase in total peripheral resistance, pre-ejection period, plasma renin activity, aldosterone, and prostaglandin 12 were observed during HDT in both groups. There were no significant differences in these parameters between the two groups. CONCLUSIONS: Brief daily LBNP sessions were effective in preventing orthostatic intolerance induced by 21 d HDT bed rest. However, it did not improve cardiac pump and systolic functions and did not preserve volume regulating hormones.     

21d头低位卧床期间第一周和最后一周下体负压锻炼对立位耐力和心功能的影响

目的观察在 2 1d头低位卧床的第一周和最后一周进行下体负压锻炼对立位耐力和心功能的影响。方法 1 2名健康男性志愿者 ,随机分为对照组和LBNP组 ,每组 6人 ,均参加 - 6°头低位倾斜卧床实验。对照组在卧床期间不做任何处理 ,LBNP组在卧床第一周和最后一周 ,每天进行 1h、- 30mmHg的下体负压锻炼。卧床前和卧床第 1 0、2 1天在倾斜床上进行 3次立位耐力检查 ,卧床期间测量心脏泵血和收缩功能等指标。结果卧床前两组 1 2名被试者均顺利通过立位耐力检查。卧床第 1 0和 2 1天 ,对照组所有被试者均不能通过立位耐力检查 ,而下体负压组仅有 1人未通过 ,卧床第 2 1天下体负压组( 1 9.7± 0 .9min)平均耐受时间较对照组 ( 1 5 .0± 3.2min)显著延长 (P <0 .0 5 )。对照组每搏输出量(SV)及心输出量 (CO)在卧床第 3、1 0天较卧床前显著降低 (P <0 .0 5 ) ,而LBNP组SV及CO在卧床期间均无显著性变化 ;两组的射血前期 (PEP) /左室射血时间 (LVET)在卧床第 3、1 4天均显著升高 (P <0 .0 5 )。两组间比较 ,LBNP组PEP/LVET在卧床第 3天较对照组显著降低 (P <0 .0 5 ) ,LVET在卧床第 3、7和 1 4天较对照组显著升高 (P <0 .0 5 )。结论 2 1d头低位卧床可引起立位耐力、心脏泵血和收缩功能显著降低 ;在 2 1d头低位卧床的     

The role of the rehabilitation brace in restoring knee extension after anterior cruciate ligament reconstruction: a prospective controlled study

To evaluate the effects of a rehabilitation brace locked in extension for the first week on the recovery of full extension after ACL reconstruction we compared two groups of subjects who underwent ACL bone-patellar tendon-bone reconstruction. The brace was unlocked twice a day for assisted physiotherapy. In Group A, 18 male subjects wore a post-operative brace locked from 0 degrees to 90 degrees. In Group B, 18 male subjects wore the same post-op brace locked in full extension for the first week. In both groups the brace was unlocked (0 degrees -120 degrees ) at the beginning of the second postoperative week, and then removed at the beginning of the third week. All the subjects followed the same rigorous, accelerated rehabilitation protocol. Each subject was evaluated pre and post-operatively (at second, fourth and eighth week) with bubble-level heel height difference (HHD) measurements and KT 1000 arthrometric assessment at the fourth postoperative month. Preoperative bubble-level HHD measurements of the two groups were statistically similar (Group A 0.6 cm, Group B 1 cm; not significant, n.s.). At the fourth week (Group A 2.2 cm, Group B 0.6 cm) and eighth week (Group A 1.6 cm, Group B 0.1 cm) follow-ups, bubble-level HHD measurements showed that the extension of the operated knees of Group B was significantly greater than in Group A. KT 1000 arthrometric scores showed no difference between the two groups (Group A 1.8 mm, Group B 1.5; n.s.).     

Functional activity of the pituitary-thyroid gland system during 370-day anti-orthostatic hypokinesia

The concentrations of the thyrotrophic hormone (TTH). bound thyroxine (T4), free thyroxine (FT4), and triiodothyronine (T3) were measured by RIA in the blood of 10 test subjects during a 370-day head-down tilt study and a 250-day recovery period after it. The concentrations of TTH, FT4, and T3 decreased during bed rest and did not return to norm during recovery. It can be assumed that during bed rest TTH stimulation of the thyroid gland declines, which can act as an adaptive response to lower physical load.