拉萨世居藏族青年的最大氧摄取和氧转运功能

对拉萨市(海拔3658m)16名世居藏族和20名已习服的移居汉族健康青年男性的最大氧摄取、最大运动负荷及其影响因素进行了对此研究。结果发现在最大努力作功时,藏族的最大氧摄取量、最大运动负荷量、潮气量、肺通气量以及氧脉搏等均大于移居汉族。说明西藏高原世居藏族具有更佳的氧转运功能,对高原低氧已获得了良好的生理适应。     

高海拔对流量-容积曲线和通气功能的影响

平原人长期移居高原环境对慢性低氧的通气适应,国内外学者研究甚多,一致认为主要是由于低氧刺激引起的过度通气来实现。而通气适应的力学机制国内研究甚少。本工作对昭觉地区(海拔2200m)从青少年到成年的世居彝族和移居汉族进行肺通气功能观察,初步探     

缺氧对世居高原藏族人脐静脉内皮细胞ET和NO水平的影响

目的: 观察世居高原藏族人静脉血ET和NO含量和缺氧对培养脐静脉内皮细胞ET和NO水平的影响,以期从胎儿生长发育的角度探讨人类高原适应的机制.方法: 分别以放射免疫分析法和Greiss法测定世居高原藏族、移居高原汉族和平原汉族人静脉血ET和NO含量.体外培养世居高原藏族和移居高原汉族新生儿UVECs,分为4组:①世居高原藏族人UVECs常氧组(TC);②世居高原藏族人UVECs缺氧组(TH);③移居高原汉族人UVECs常氧组(HC);④移居高原汉族人UVECs缺氧组(HH),收集培养上清液测定ET和NO含量.结果: 世居高原藏族人静脉血NO水平显著高于移居高原汉族人,而ET水平显著低于移居高原汉族人.体外低氧(0.5% O2)条件培养12 h和24 h时,TH组ET浓度显著低于HH组,而HH组与TH组和HC组与TC组相应时间点之间的NO浓度差异无显著性意义.结论: 缺氧时世居高原藏族人UVECs ET分泌增高的程度较低,可能有助于保持相对低的血管张力,有利于胎儿血液供应.     

胸内正压对正常人左室功能影响及其力学原理

目的:探讨胸内正压对正常人左室射血及充盈的影响及其力学原理。方法:超声心动图观测30例正常人初始时与标准乏氏动作张力期10s时左室舒张末容积(LVEDV)、左室收缩末容积(LVESV)、每搏量(SV)、射血分值(EF)、流入道血流速度(E峰、A峰)、E/A值、二尖瓣环舒张早期运动速度(e)及舒张早期充盈压(E/e)的变化。结果:与初始时比较,标准乏氏动作张力期LVEDV、LVESV及SV减低而心率(HR)增快(P均<0.001),EF值增加,但无统计学意义(P>0.05);E峰与E/A值减低(P均<0.05);e没有变化(P>0.05),E/e值减低(P<0.05)。结论:胸内正压对左室游离壁的力学作用促进了左室收缩运动而阻碍了左室舒张运动,会引起EF值增加,E峰及E/A值减低;2,胸内正压降低了肺静脉系统与心脏的跨壁压力,增加了血流阻力也是导致肺静脉系统与左室血液回流减少,E峰减低,E/e值减低的一个原因。     

高原移居汉族和世居藏族低、高氧通气反应性研究

高原移居汉族和世居藏族低、高氧通气反应性研究杨生岳,冯恩志,马子琪,詹正嵩（西宁解放军第四医院８１００１４）在海拔４７５０ｍ,对高原世居藏族和由平原移居该高度不同时间的汉族作了低、高氧通气反应研究。１对象与方法受试者分３组：短居组（第１组）：为平原移...     

模拟高原低压低氧环境对大鼠心脏结构和功能影响*

目的: 探讨模拟海拔7 000 m低压低氧环境对大鼠心脏结构和功能的影响。方法: 96只雄性SD大鼠随机分为常压常氧对照组(对照组)和高原低压低氧组(低氧组)。低氧组大鼠放置于大型多因素复合环境模拟实验舱内,模拟海拔7 000 m高原环境饲养。实验舱运行时间23 h/d,控制昼夜比大约12 h∶12 h;对照组置于相同条件的常压常氧环境下饲养。低氧组又根据低氧时间不同分为3 d组、7 d组、14 d组和28 d组,同时设置与各低氧组相对应的对照组,每组均12只大鼠。应用超声心动图、心电图、血常规、血生化综合评价高原低压低氧环境下大鼠心脏结构和功能变化,心肌组织HE染色分析心肌组织病理变化。结果: 与相同时间点对照组比较①随着低压低氧暴露时间延长,大鼠体质量增长明显缓慢,动脉血氧饱和度14 d和28 d显著降低(P＜0.05)。②低氧组大鼠左心室舒张末期前壁厚度(LVAWD)及左心室舒张末期后壁厚度(LVPWD)于28 d时显著升高(P＜0.05)。舒张末期左心室腔直径(LVIDD)及收缩末期左心室腔直径(LVIDS)于28 d时明显降低(P＜0.05,P＜0.01)。左心室射血分数(EF%)、左室短轴缩短率(FS%)、肺静脉血流峰值速度(PV peak velocity)及肺静脉血流峰梯度(PV peak gradient)于低氧7 d 下降明显(P＜0.05,P＜0.01),低氧14 d 及低氧28 d 恢复。③低氧组大鼠心电图QRS间期与QT间期在14 d 及28 d 显著延长(P＜0.05,P＜0.01)。ST段3 d和7 d显著压低(P＜0.05,P＜0.01)。R波振幅于 7 d、14 d 及28 d 显著降低(P＜0.05,P＜0.01)。④低氧各组大鼠红细胞计数(RBC)、血红蛋白(HGB)、红细胞分布宽度(RDW)均明显升高(P＜0.01)。血小板计数(PLT)于14 d 及28 d 明显下降(P＜0.01)。血肌酐(CR)于14 d及28 d显著升高(P＜0.05)。⑤心肌病理提示,低氧3 d 和7 d 可见心肌水肿、肌浆凝聚,横纹不清,灶状变性和坏死伴炎性细胞浸润。低氧14 d 和28 d 心肌组织炎症性病理损伤逐渐减少。心肌细胞逐渐肥大,成纤维细胞逐渐增生。心肌间质胶原纤维逐渐增多等心肌代偿修复性病理变化显著。结论: 暴露于模拟海拔7 000 m低压低氧环境下3 d大鼠心功能明显降低,7 d最为显著。     

α- 酮酸片对维持性血液透析患者心脏功能和结构的影响

目的:探讨α-酮酸片(α-KA)对维持性血液透析(MHD)患者心脏功能和结构的影响。方法:观察30例α-酮酸片(商品名:开同)治疗组维持性血液透析患者与30例对照组患者,分别在治疗前及治疗6个月后超声心动图测定心脏结构指标:左房收缩末期内径(LADs)、左室舒张末期内径(LVEDd)、室间隔舒张末期厚度(IVSTd)、左室后壁舒张末期厚度(LVPWTd),左房内径指数(LAI)、左心室心肌重量指数(LVMI)、相对室壁厚度(RWT),心脏功能指标:左室射血分数(LVEF),左室短轴缩短率(FS),二尖瓣口舒张早期和晚期最大血流速度比(E/A)各项指标等检测,比较治疗前后各指标变化。结果:治疗组MHD患者心脏结构指标:左房收缩末期内径(LADs)、左室舒张末期内径(LVEDd)、室间隔舒张末期厚度(IVSTd)、左室后壁舒张末期厚度(LVPWTd),左房内径指数(LAI)、左心室心肌重量指数(LVMI)值均明显低于对照组,二者差异有显著性(P<0.05),两组相对室壁厚度(RWT)相比没有明显的差异(P>0.05)。心脏功能指标:左室射血分数(LVEF),左室短轴缩短率(FS),二尖瓣口舒张早期和晚期最大血流速度比(E/A)值较对照组明显增高(P<0.05),有统计学意义。结论:α-酮酸片可以改善MHD患者的心脏结构和功能,其对MHD患者心血管并发症的预防和治疗有一定临床指导意义。     

降香通过抗氧化应激改善后负荷增加型心衰小鼠的心脏功能

目的:研究降香对后负荷增加引起的的心脏功能下降的保护作用及其机制。方法:雄性C57小鼠30只,随机分为三组,分别给予假手术(sham)、主动脉弓结扎(Transverse aortic constriction,TAC)手术和主动脉弓结扎手术降香治疗(TAC+DO)处理。通过灌胃给药4周,随后超声检测心脏功能、四腔心切片观察心肌重构,RT-PCR检测左心室αMHC、βMHC的m RNA表达、相应试剂盒心肌总抗氧化能力(TAOC)和丙二醇(MDA)含量。结果:同sham组相比,TAC组射血分数(EF),αMHC m RNA水平和TOAC均显著降低,且左室舒张末内径(LVIDd)、左室舒张期后壁厚度(LVPWd)、左室质量(LV mass)、心肌质量/胫骨长度(HW/TL)及β及β度、MDA均显著增加。同TAC组相比,DO组射血分数(EF),αMHC m RNA水平和TOAC均显著增加,且左室舒张末内径(LVIDd)、舒张末室间隔厚度(IVSd)、左室质量(LV mass)、心肌质量/胫骨长度(HW/TL)及βMHC、MDA均显著下降。在离体培养的心肌细胞,H_2O_2可显著增加细胞内ROS含量,给予降香或TEMPOL处理均可减轻H_2O_2诱导的氧化应激并增加心肌细胞存活率。结论:降香可通过降低氧化应激抑制线粒体分裂并改善后负荷增加型心衰的心脏功能。     

高原健康居民某些内分泌激素的变化及其生理意义

本文在海拔10m(青岛)、2260m(青海西宁)和3700m(青海玉树)三个高度,用放射免疫法,测定445例健康人血四碘甲腺原氨酸(T_4)、三碘甲腺原氨酸(T_3)、3,3’,5’三碘甲腺原氨酸(rT3)皮质醇(F)和醛固酮(ALD)含量。结果发现:(1)高海拔地区世居藏族与有15年以上移居史的汉族居民五项测值间无显著差别(P>0.05);(2)高海拔地区居民T_3、T_4、F和ALD含量降低(P<0.05～0.001),而rT3则升高(P<0.01)。这些变化的生理意义,可能反映了高原居民对低氧环境的一种慢性适应机制。在某些高原疾病防治中,适当应用肾上腺皮质激素,可能有一定临床价值。     

350m氦氧模拟饱和潜水过程中潜水员坐位踏车时心缩间期的变化

在350m氦氧模拟饱和潜水过程中,对4名男性潜水员采用耳密度图导数图方法观察坐位踏车时心缩间期变化。在压力(300、230、135m)下和减压后的主要变化是等容收缩期、射血前期(PEP)和PEP/左室射血时间加大,与加压前比较有显著差异,尤其在踏车负荷加重时更为明显。提示心肌收缩力受高气压的影响而降低。     

不同海拔高度对健康成年男性心脏血流动力学和心电图的影响

目的:监测中国南极冰盖考察预选队员心血管系统随海拔增高的变化,探讨筛查低氧易感队员和急性高原病的防治。方法:用无创血流动力学监护仪和十二导联心电图机,在北京(40 m)、拉萨(3 650 m)、羊八井(4 300 m)对第25次和26次南极冰盖考察预选队员心血管功能进行连续动态性监测。结果:随着海拔的增高,心率、收缩压、舒张压、平均动脉压、外周血管阻力、外周血管阻力指数显著升高(P0.05),心输出量、心指数、搏出量、搏出指数、加速度指数、速度指数、左心射血时间显著降低(P0.05),预射血期呈降低趋势(P0.05)。结论:随着海拔的增高,预选队员的外周血管阻力显著升高,左心泵血和收缩功能减弱且与Q-TC间期呈负相关。     

Association of high-altitude systemic hypertension with the deletion allele-of the angiotensin-converting enzyme (ACE) gene

People who visit high-altitude areas are exposed to a stressful environment and a good percentage of them suffer from high-altitude-induced diseases, including systemic hypertension. Identification of genetic markers for high-altitude-induced diseases would help to reduce the rate of morbidity/mortality from such diseases. The development of systemic hypertension on exposure to high altitude (3,500 m) for 30 days in otherwise normotensive natives of low-altitudes was investigated. The angiotensin-converting enzyme (ACE) insertion/deletion (I/D) genotypes and renin-angiotensin-aldosterone system were simultaneously studied. In the hypertensives during their stay at high altitude, the ACE D allele frequency was significantly higher than in the normotensives (0.67 versus 0.32 chi(2)(1) = 10.6, P < 0.05). In the normotensives during their stay at high altitude, there was no significant increase in plasma aldosterone levels despite increased plasma renin activity. Results of the present study suggest that environmental changes and pre-existing genetic factors, namely the ACE D allele, might be two of the factors predisposing natives of low altitudes to systemic hypertension, a polygenic disease, at high altitude.     

Effect of altitude exposure on thermoregulatory response of man to cold.

The thermoregulatory responses to 10 degrees C (for 3 h) were investigated in 1) 12 natives from sea level (lowlanders) at 150 m, and on arrival at 3,350 and 4,340 m; 2) 6 of these during a 6-wk sojourn at 4,360 m, and on return to sea level; and 3) 5 natives from each of the two altitudes (highlanders) in their respective habitat, and after descent to 150 m. The cold-induced increase in the rate of O2 consumption (Vo2) of the lowlanders was significantly smaller at both altitudes than at sea level. It did not recover substantially during the 6 wk at altitude, but was restored to its initial rate on return to sea level. By contrast, visible shivering activity was augmented on arrival at altitude. It persisted throughout the 6 wk there, but was greatly depressed on return to sea level, despite the increased Vo2. Mean skin temperatures (Tsk) stabilized in the cold at significantly higher values at altitude. Rectal temperature (Tre) decreased similarly at all altitudes. Vo2 of the highlanders in the cold was significantly greater at sea level than at their resident altitudes, although shivering activity was less intense; Tsk stabilized at significantly lower levels at 150 m than at either altitude. These results indicate that altitude exposure reduces the calorigenic response of man to cold, and that this effect is not moderated by acclimatization to altitude, yet is reversible immediately on descent to sea level. The component of cold thermogenesis which appeared to be reduced by altitude exposure was nonshivering thermogenesis rather than visible shivering.     

Adaptation of the circulatory system to frequently repeated submaximal workloads in the light of left ventricular contraction analysis

In two groups of healthy men aged 20-22 years the left ventricular systolic time intervals were evaluated by the method of Weissler et al. during frequently repeated workloads and restitution. Each exercise was carried out on a Zimmerman cycle ergometer during 10 minutes, and was repeated five times at 50-minutes intervals from 8.00 o'clock a.m. Group I (15 subjects) performed the exercise at a stable workload which produced during the first exercise heart rate acceleration to 170/min, but gave a successive further rise in the heart rate during consecutive exercises. Group II (11 subjects) performed all exercises to a stable rise in heart rate to 170/min with decreasing workloads. It was found that successive exercises caused in both groups a similar decrease of the left ventricular ejection time index (LVETI), pre-ejection period (PEP), isovolumetric contraction time (ICT), and decrease of the PEP/LVET index (p less than 0.05). Each successive exercise began with higher values of LVETI, PEP, ICT and PEP/LVET than the first one. No significant differences were found in the values of left ventricular systolic time intervals in both groups (p greater than 0.05). The duration of restitution of normal values of the left ventricular systolic time intervals after successive exercises was not changing but the tolerance of these exercises measured by heart rate increase and work performed decreased successively.     

Cell mediated immunity at high altitude

Cell mediated immunity (CMI) was assessed by determining total and differential leucocyte and absolute lymphocyte counts, T and B-rosettes, PHA-blast transformation of lymphocytes, lymphocyte migration index (LMI), and DNCB response in 66 sea-level residents, 45 temporary residents, and 24 natives at high altitude (3,692 m). An accentuated CMI, indicated by increase in PHA-blasts, increased lymphocyte migration index, and intense DNCB response, was present, despite a mild decrease in total leucocytes in temporary residents and in lymphocytes in natives at high altitude. While T-rosettes did not show any change in numbers, B-rosettes were increased in temporary residents, and natives at high altitude. A qualitative change had, therefore, occurred in lymphocytes at high altitude. CMI is equally augmented in temporary residents and natives at high altitude and prevails at a higher plane than at sea-level. Augmentation of CMI at high altitude, therefore, could be used as a therapeutic measure.     

Systolic time intervals in burn injury

Systolic time intervals were studied in 28 young, previously healthy burn patients (TBS 10-90%) on 145 occasions. A NEK 116 type 3 channel recorder of 100 mm/sec paper speed was used. Synchronous ECG recordings in lead II, PCG in the m "1" frequency band, and external carotid pulse tracings were recorded. RR, QS2, S1S2, LVET, PEP, PEP/LVET and QT, QTc, QS2-QT intervals were measured in 5-10 cardiac cycles in each of the examinations. Calculation of the additional parameters ICT, LVET/ICT, DT, EVR, PRP, EF and SV values were correlated to the extent of, and the time elapsed since, burn injury. The derivated parameters and statistical analysis were performed on a Commodore 64 type computer based on a software program. Elongation of QTc (greater than 440 msec) and frequent electrodynamic failure (QT-QS2 greater than 40 msec) especially during the first postinjury week were found characteristic in severe injury. In 53% the PEP/LVET ratio was less than 0.31, mean 0.32 +/- 0.093. In 21 cases of severe hypovolaemia the increase of PEP raised this value beyond 0.41. With the exception of 3 examinations, QS2I was normal or shortened. Calculated EF were normal or increased, SV reduced being interdependent with burn extent and shortening of DT. In patients with severe burns, oxygenization was inadequate (EVR less than 0.8); it showed an inverse correlation to HR. The simultaneously high LVET/ICT ratio and shortened ICT values pointed to an increase in contractility.     

心脏收缩时间间期与冠状动脉狭窄程度或范围的相关性研究

心脏收缩时间间期(STI)通过单笔心电图机叠加记录ECG、心音图和颈动脉图后测得。对83例患者进行了STI均值与选择性冠状动脉造影(CAG)及左室造影的相关研究。患者除陈旧性心肌梗塞及室壁瘤外,根据冠状动脉(CA)狭窄程度而分组。STI随CA狭窄程度及范围的增加而显著异常,提示心功能随心肌缺血程度加重而进行性恶化。左室射血分数(LVEF)的降低也支持这一点。CA狭窄程度、范围与射血前时间/左室射血时间(PEP/LVET)呈正相关。在决定左室功能的异常方面,PEP/LVET和LVEF的临床意义完全相同。提示STI在评价冠心病心功能上是有用的。排除影响STI的某些因素后,PEP/LVET≥0.38可作为判断冠心病左心功能减退的标志。但轻度CA狭窄患者的STI可正常,这可能与静息时尚有足够的CA贮备力有关。     

运动负荷对青年学生和运动员心脏功能的影响

用无创法(阻抗法)测量了40名青年学生和40名运动员在两种运动负荷(50W和150W)运动前、运动后即刻和恢复时程的收缩时间间期(STI)和心率(HR)。在静态时,“运动员组”的心率较缓(P<0.01)、QS_1较长(P<0.05)、PEP/LVET比值较大(P<0.05和P<0.01)、LVETc较短(P<0.001)。运动后即刻,“学生组”和“运动员组”都表现为QS_z、LVET、PEP、IVCT、QS_1缩短、PEP/LVET比值减小、心率增速和LVETc延长。但“运动员组”QS_2、LYET的缩短和心率增速的程度较少,而PEP/LVET比值的减小和LVETc延长的程度较大。除PEP/LVET比值外,其余各项指标的恢复速度均与负荷量有关。“运动员组”的恢复速度较快,尤其在150W时更为明显。本文指出:1)用阻抗法测算动态下的STI更为实用;2)系统训练可提高心脏活动的潜力,改善泵功能,促进心脏活动的调节速度。     

Aspects of physical activity in high altitude natives

Altitude adaptation was measured at sea level and high altitudes in sea level adapted and high altitude adapted natives. Tests of work capacity as measured by O₂ consumption, pulse rate, and ventilation rate are reported. It is noted that comparing our results with those of other investigators is difficult due to variations in terminology and procedure. This suggests the necessity of more precise definitions in studies of the physical activity of high altitude natives.     

急进高海拔时健康人夜间睡眠、呼吸状态和血氧饱和度的变化

在海拔2300m选择健康成年男性5人,急进抵海拔4660m,用多导监测仪分别在两地连续7h监测夜间睡眠、呼吸状态和血氧饱和度变化,进行自身对比。结果发现:(1)急进高海拔后,总睡眠时间、有效睡眠指数、Ⅲ～Ⅳ期深睡眠均较中度高原减少(p<0.01);总觉醒时间、Ⅰ～Ⅱ期浅睡眠高海拔较中度高原增多(p<0.05):(2)急进高海拔后,有3名健康人出现周期性呼吸,其中1名健康者出现周期性呼吸119次,伴有中枢性睡眠呼吸暂停,最低Sao_2为78％;(3)同海拔高度夜间睡眠时与清醒时Sao_2相比较,中度高原下降4.2％,高海拔下降11.2％(p<0.01);高海拔与中度高原夜间清醒时Sao_2相比较下降7.4％,睡眠时下降14.4％(p<0.001)。结果提示:(1)睡眠加重了高原人原有的低氧血症;(2)低氧血症导致睡眠结构的紊乱和睡眠质量的降低;(3)睡眠中出现的周期性呼吸,应视为机体的一种自我保护机制;(4)频发的周期性呼吸或睡眠呼吸暂停将影响大脑机能。