急进高原与平原大鼠肠黏膜屏障紧密连接蛋白occludin表达的对比研究

目的:探讨急进高原与平原大鼠肠黏膜屏障紧密连接蛋白occludin在肠上皮细胞中的表达变化。方法:48只Wistar大鼠随机分为平原组(n=24)和高原缺氧组(n=24),每组再按2、4、6 d时间点随机分为3个亚组(n=8)。各组均用免疫组织化学法检测occludin蛋白表达,RT-PCR法检测occludin mRNA含量。结果:与平原组各时间点比较,高原缺氧组occludin蛋白及occludin mRNA含量显著降低(P<0.01)。结论:急进高原可使大鼠肠黏膜屏障紧密连接蛋白occludin表达减少,导致肠黏膜屏障损伤。     

黄芩苷与红景天胶囊对急性高原病预防作用比较

 目的 探讨黄芩苷胶囊对急性高原病(acute mountain sickness, AMS)的预防作用。方法 采用随机对照的研究方法, 80名急进高原健康男性青年随机分为3组, 黄芩苷组(n=32)、红景天组(n=24)和安慰剂组(n=24)。3组在进入高原前2 d、进入高原后连续3 d分别服用黄芩苷胶囊(0.5 g, 2次/d)、红景天胶囊(0.76 g, 2次/d)和安慰剂(2粒, 2次/d)。检测急进高原前(海拔397 m)和急进高原后(3658 m)受试者氧饱和度、心率、收缩压、舒张压, 彩色多普勒超声测量肺动脉收缩压(pulmonary artery systolic pressure, PASP)和平均肺动脉压(mean pulmonary arterial pressure, MPAP), 统计急进高原后各组的AMS发病率。结果 急进高原后安慰剂组、黄芩苷组和红景天组的AMS发病率分别为58.3%(14/24)、25.0%(8/32)和29.2%(7/24), 与安慰剂组比较, 黄芩苷组及红景天组AMS发病率明显降低, 差异有统计学意义(P<0.05)。与急进高原前比较, 各组受试者急进高原后心率、血压及肺动脉压均升高, 氧饱和度降低(P<0.05);与安慰剂组比较, 黄芩苷组血压及心率明显降低(P<0.05), 红景天组急进高原后氧饱和度升高、肺动脉压降低(P<0.05)。结论 黄芩苷组可能通过降低血压及心率预防AMS的发生, 红景天胶囊可能通过升高氧饱和度, 降低PASP、MPAP预防AMS的发生。     

硝苯吡啶对急进高原现场幼猪血流动力学及血气的影响

目的 :了解硝苯吡啶 (Nifedipine ,NF)对高原急性缺氧的治疗作用。方法 :利用右心导管法对急进高原现场急性缺氧幼猪应用NF前后的血流动力学及血气各时相点的变化情况进行观察。结果 :急进高原现场幼猪应用NF后肺动脉压 (PAP)及肺血管阻力 (PVR)显著下降 (各时相点分别为P <0 .0 5～ 0 .0 1 ) ,心输出量 (CO)及动脉血SaO2 、PaO2 显著升高 (P <0 .0 5～ 0 .0 0 1 ) ;而心率 (HR)、肺动脉楔压 (PAWP)、平均体动脉压 (mSAP)、PH、HCO3- 、PaCO2 变化无统计学意义。结论 :NF可明显降低急进高原现场幼猪的肺动脉压 (PAP) ,提高CO和动脉血SaO2 、PaO2 ,有利于急性缺氧的治疗。     

氧化应激在低压缺氧性肺动脉高压形成中的作用

目的观察低氧对血清中活性氧(ROS)水平的影响,探讨氧化应激在低压缺氧性肺动脉高压形成中的作用。方法将24只Wistar大鼠随机分为平原对照组(C组),缺氧组(H组),N-乙酰半胱氨酸组(N组),缺氧+N-乙酰半胱氨酸组(H+N组)。建立低压缺氧模型21 d后,测定其右心室收缩压(RVSP)和平均肺动脉压(mPAP);HE染色观察各组大鼠的肺动脉壁厚度;比色法测定血清中ROS的含量。结果与C组相比,H组RVSP、mPAP明显升高(均P<0.05),HE染色示H组肺动脉壁增厚,且血清中ROS水平明显升高(P<0.05);给予ROS清除剂NAC后,RVSP及mPAP降低,肺血管重塑减弱。结论低氧时氧化应激参与了低压缺氧性肺动脉高压的形成。     

高原低氧环境对大鼠红细胞和组织中SOD活性的影响及中药调节效应的观察

平原地区大鼠进入高原地区后,其红细胞中sOD活性显著降低(P<0.05,P<0.01);经服红景天素后红细胞SOD活性增高与NS组比较P<0.05,P<0.01。高原地区大鼠以肝、脑、肾组织中SOD活性降低最为明显,其中阿尼玛卿山组与西安组比较P<0.01或P<0.001;西宁组与西安组比较P<0.05或P<0.01。红景天素组大鼠进入海拔5100m地区后,其脑和肾组织中SOD活性较NS组显著升高(P<0.01或P<0.001)。提示红景天素能有效地防治大鼠急进高原后所引起的红细胞和组织中SOD活性的降低,且随着海拔的升高,此种效应更为明显。     

天麻素对模拟高原缺氧大鼠动脉血气及脑组织损伤的影响

目的 研究天麻素对模拟高原缺氧大鼠动脉血气及脑组织损伤的影响.方法 成年健康雄性Wistar大鼠60只,随机分为常氧模型(N)组,缺氧模型(M)组,红景天(RC)对照组,天麻素低剂量(GAS-L)组,天麻素中剂量(GAS-M)组,天麻素高剂量(GAS-H)组,每组10只.每日定时灌胃给药,连续7d.采用低压氧舱模拟海拔8000m高原环境,缺氧12h后,测定各组大鼠动脉血气,观察大鼠脑组织病理变化,并测定脑组织相关生化指标水平.结果 与N组比较,M组大鼠氧分压(PO2)、血氧饱和度(SO2)、氧合指数(PO2/FiO2)、钠离子(Na+)、实际碳酸氢根(HCO3–)明显下降(P<0.01),乳酸(Lac)、血红蛋白(Hb)浓度明显上升(P<0.01);大鼠脑组织出现病理性损伤;脑组织中丙二醛(MDA)、过氧化氢(H2O2)含量明显升高(P<0.01),谷胱甘肽(GSH)含量、谷胱甘肽过氧化物酶(GSH-Px)活性明显降低(P<0.01).与M组比,GAS-L组PO2、SO2、PO2/FiO2明显升高(P<0.05,P<0.01);GAS三个剂量组Na+、HCO3–均明显升高(P<0.05,P<0.01);GAS-L及GAS-H组Lac含量明显降低(P<0.01,P<0.05);GAS-H组Hb明显升高(P<0.01).RC及GAS组脑组织病理损伤较M组轻.与M组相比,GAS三个剂量组脑组织MDA明显降低(P<0.05,P<0.01),H2O2有降低趋势,但差异无统计学意义(P>0.05);GSH含量及GSH-Px活性均明显升高(P<0.05,P<0.01),但无明显剂量依赖性.结论 天麻素能够对模拟高原缺氧大鼠动脉血气及脑组织损伤起到保护作用.     

低氧性肺动脉高压大鼠PLA_2、TNF的含量变化及意义

为了探讨ＰＬＡ2、ＴＮＦ与肺血管收缩、肺动脉高压形成的关系,作者建立了常压低氧大鼠肺动脉高压模型,观察这些物质的含量变化。将缺氧组大鼠放入常压缺氧舱内缺氧,缺氧期间舱内氧浓度控制在10%,每天缺氧8ｈ,连续21ｄ。缺氧结束后采用右心导管法检测血流动力学指标。包括肺动脉收缩压、肺动脉舒张压、右室收缩压(ＲＶＳＰ)等。测压结束后将正常对照组、缺氧组的大鼠心脏取出,并制备肺组织匀浆,行支气管肺泡灌洗(ＢＡＬ)术,测定血清、肺组织、ＢＡＬＦ中的磷脂酶Ａ2活力和ＴＮＦ的含量。结果显示缺氧组大鼠ｍＰＡＰ、ＲＶＳＰ均明显升高,说…     

急进高原驻训官兵心身健康水平调查与分析

目的:调查了解急进高原驻训官兵的心身健康水平。方法:采用常规方法、自评焦虑量表(SAS)及自评抑郁量表(SDS)等对急进高原驻训官兵51例的血氧饱和度、心率、血压水平的变化,以及焦虑、抑郁情绪进行测评。结果:驻训官兵在海拔4400m时的心率、收缩压、舒张压水平显著高于海拔480m时的水平;SO2水平显著低于海拔480m时的水平(P<0.05)。不同海拔高度驻训官兵焦虑及抑郁评分差异不显著(P>0.05)。结论:急进高原驻训官兵进入驻训区时低氧状况明显,应警惕急性高原病的发生;驻训前进行心理干预可降低官兵心理应激反应程度。     

红景天对急进高原大鼠生理病理变化的影响

目的平原Wistar大鼠急进海拔4300 m高原后,给予红景天药物干预,观察大鼠生理和病理状态变化情况。方法将21只成年健康Wistar大鼠按体质量随机分为高原缺氧组（空白组）、高原缺氧＋乙酰唑胺组（对照组）、高原缺氧＋红景天组（给药组）,急进高原后连续给药5 d后,取眼眶静脉丛血分析其主要生化指标,同时解剖大鼠,取腹主动脉血分析其主要血气指标,完整摘取肝脏和肺组织进行病理切片观察。结果与空白组相比,对照组HB、Hct、CCl-、CCa2＋均显著性升高（P〈0.05）,ALT、ALP、pH、CHCO3-、BB、BE均显著性降低（P〈0.05或P〈0.01）,给药组ALT、ALP、ALB、UREA均显著性降低（P〈0.05）;与对照组相比,给药组pH、CHCO3-、BB、BE均显著性上升（P〈0.05）,ALP、Urea、HB、Hct、CCa2＋均显著性下降（P〈0.05）。病理结果显示,高原缺氧对大鼠肝、肺损伤严重,红景天和乙酰唑胺给药组损伤均比空白组小。结论红景天具有一定的抗缺氧反应作用,能够减轻急进高原大鼠的病理损伤,但不能完全避免损伤,说明红景天治疗高原反应有一定的局限性。     

急进高原幼猪吸入NO后的动脉血气及酸碱平衡变化

生物体急进高原后,由于低吸入气氧分压(PIO2)、低肺泡气氧分压(PAO2)及低肺泡-动脉氧分压差(AaDO2),机体数分钟后便可出现SaO2下降而导致机体缺氧,此时如果缺氧得不到及时的纠正而机体又不能有效地代偿适应,则可能导致急性高原病的发生。NO作为一种高效的生物活性因子已被广泛地用于治疗高原肺水肿(HAPE)。本文旨在了解外源性NO对高原急性缺氧的治疗作用及其作用机制。作者利用右心漂浮导管法对急进高原幼猪(比照急性高原病患者)吸入海拔3658m空气平衡的浓度为0.001%的NO气体后即刻动脉血气及酸碱平衡变化情况进行比较观察。结果急…     

增氧呼吸器对严重急性低压缺氧的防护作用及氧自由基的影响

目的 探索增氧呼吸器对严重急性低压缺氧的防护作用及氧自由基的影响.方法 30只雄性新西兰大白兔随机分为3组,对照组(Con)暴露在海拔400 m(西安市的平均海拔高度)不佩戴增氧呼吸器;急性低压缺氧组(H)暴露在模拟海拔8 500 m环境180 min,不佩戴增氧呼吸器;急性低压缺氧呼吸器防护组(P)暴露在模拟海拔8 500 m环境180 min,佩戴增氧呼吸器.各组动物均于进舱时、气压降至海拔8500 m即刻、30、60、120、180 min抽取动脉血0.5 mL进行实时血气分析,并于实验结束时抽取动脉血2mL进行超氧化物歧化酶(SOD)活性和丙二醛含量(MDA)测定.结果 H组各时间点PaO2、SaO2及终点SOD活性均低于Con组,P组则均高于H组,两组血气均于8 500 m 30 min时降至最低.血清MDA浓度H组显著高于Con组,P组显著低于H组,各组间比较均P＜0.001.结论 佩戴增氧呼吸器能提高严重急性低压缺氧时PaO2、SaO2及SOD活性,从而在一定程度上防护缺氧所致的自由基损害.     

硝苯吡啶对急进高原现场幼猪氧动力学的影响

目的 :了解硝苯吡啶 (Nifedipine ,NF)对急性缺氧幼猪氧动力学的影响。方法 :利用右心漂浮导管法对快速进入高原急性缺氧幼猪应用NF后氧动力学的变化进行观察。结果 :应用NF后 ,急性缺氧幼猪的肺动脉平均压 (mPAP)、肺血管阻力 (PVR)显著降低 (其中mPAP :P <0 .0 1,PVR :P <0 .0 0 1) ;心输出量 (CO)、SaO2 、PaO2 、氧输送 (DO2 )、氧消耗 (VO2 )、氧摄取率 (O2Ext)显著提高 (CO :P <0 .0 1,SaO2 、PaO2 、DO2 、VO2 、O2Ext:P <0 .0 0 1)。结论 :NF能降低急性缺氧幼猪的PVR ,通过改变CO而提高组织的DO2 、VO2 ,改善组织因缺氧引起的氧代谢障碍。     

Intermittent hypoxia does not increase exercise ventilation at simulated moderate altitude

Recent human studies have shown that resting hypoxic ventilatory response (HVR), which is an index of ventilatory chemosensitivity to hypoxia, increased after short-term intermittent hypoxia at rest. In addition, intermittent hypoxia leads to increases in ventilation and arterial oxygen saturation (SaO (2)) during exercise at simulated high altitude, with the increase in ventilation correlated to the change in HVR. However, no study has been made to clarify the relationship between ventilatory chemosensitivity and the exercise ventilation at moderate altitude following intermittent hypoxia during a resting state. The purpose of the present study, therefore, was to elucidate whether intermittent hypoxia at rest induces the increase in ventilation during exercise at moderate altitude that is accompanied by an increase in hypoxic chemosensitivity. Eighteen trained male runners were assigned to three groups, i.e., the first hypoxic group (H-1 group, n = 6), the second hypoxic group (H-2 group, n = 6), and a control group (C group, n = 6). The hypoxic tent system was utilized for intermittent hypoxia, and the oxygen levels in the tent were maintained at 15.5 +/- 0.1 % (simulated 2500 m altitude) for the H-1 group and 12.3 +/- 0.2 % (simulated 4300 m altitude) for the H-2 group. The H-1 and H-2 groups spent 1 hour per day in the hypoxic tent for 1 week. Maximal and submaximal exercise tests while breathing 15.5 +/- 0.01 % O (2) (simulated altitude of 2500 m) were performed before and after intermittent hypoxia. Resting HVR was also determined in each subject using a progressive isocapnic hypoxic method. In the H-2 group, HVR increased significantly (p < 0.05) following intermittent hypoxia, while no change in HVR was found in the H-1 or C group. Neither ventilation nor SaO (2) during maximal and submaximal exercise at a simulated altitude of 2500 m were changed in either group after 1 hour per day for 1 week of intermittent hypoxia. These results suggest that the change in resting hypoxic chemosensitivity after short-term intermittent hypoxia does not affect ventilation during exercise at moderate altitude.     

Effects of sildenafil on the human response to acute hypoxia and exercise

We examined the effects of the 5-phosphodiesterase (5-PDE) inhibitor sildenafil on pulmonary arterial pressure and some oxygen transport and cardiopulmonary parameters in humans during exposure to hypobaric hypoxia at rest and after exercise. In a double-blind study, 100 mg sildenafil or placebo was administered orally to 14 healthy volunteers 45 min before exposure to 5,000 m of simulated altitude. Arterial oxygen saturation (SaO2), heart rate (HR), tidal volume (VT), respiratory rate (RR), left ventricular ejection fraction (EF), and pulmonary arterial pressure (PAP) were measured first at rest in normoxia, at rest and immediately after exercise during hypoxia, and after exercise in normoxia. The increase in systolic PAP produced by hypoxia was significantly decreased by sildenafil at rest from 40.9 +/- 2.6 to 34.9 +/- 3.0 mmHg (-14.8%; p = 0.0046); after exercise, from 49.0 +/- 3.9 to 42.9 +/- 2.6 mmHg (-12.6%; p = 0.003). No significant changes were found in normoxia either at rest or after exercise. Measurements of the effect of sildenafil on exercise capacity during hypoxia did not provide conclusive data: a slight increase in SaO2 was observed with exercise during hypoxia, and sildenafil did not cause significant changes in ventilatory parameters under any condition. Sildenafil diminishes the pulmonary hypertension induced by acute exposure to hypobaric hypoxia at rest and after exercise. Further studies are needed to determine the benefit from this treatment and to further understand the effects of sildenafil on exercise capacity at altitude.     

高压氧预处理对急性低氧大鼠心肌超微结构和心功能保护机制的研究

目的 探讨高压氧(HBO)预处理对急性低氧大鼠心肌超微结构和心脏功能的影响.方法 取13只Wistar大白鼠随机分为2组:低氧组(n=7),将大鼠置于模拟海拔5400 m低压氧舱内3 d;HBO预处理组(HBO组,n=6),进入低压舱前2 d给予HBO预处理2 d,每天1次,然后置于模拟海拔5400 m低压氧舱内3 d.第4天上午在模拟海拔5400 m的低压氧舱内,2组动物用10%氨基甲酸乙酯腹腔麻醉,经右颈外静脉插入心导管至右心室、肺动脉,用多道生理记录仪连续描记肺动脉压力曲线5min,测定心率(HR)、肺动脉压力(PAP)、右室收缩压(RVSP)和舒张压(RVEDP)、右室等容收缩期心室内压力上升最大速率和右室等容舒张期心室内压力下降最大速率(±dp/dtmax>)等血流动力学指标,并观察心肌超微结构的变化.结果HBO组较低氧组HR、RVSP降低,±do/dtmax>增高,差异有统计学意义(P<0.01);肺动脉舒张压降低,差异有统计学意义(P<0.05),肺动脉收缩压、肺动脉平均压、RVEDP差异无统计学意义(P>0.05).低氧组心肌细胞线粒体肿胀、溶解,肌浆网扩张,局部区域形成许多泡状;HBO组心肌无明显病变,仅滑面内质网轻度扩张.结论 高压氧具有改善急性低氧大鼠血流动力学、降低肺动脉压、保护心功能的作用.     

高原康胶囊对急进高原大鼠血气及酸碱平衡的影响

目的：了解高原康胶囊对急性高原反应期大鼠血气及酸碱平衡的影响。方法：大鼠分两个海拔类，每类四组，对照组（蒸馏水）和高（360mg/kg体重），中（180mg/kg体重），低（30mg/kg体重）三个剂量组，灌胃给药12h后取大鼠动脉血进行血气分析，结果：两类地区高，中剂量组大鼠血氧分压（PaO2)，血氧饱和度（O2sat)均显著高于对照组和低剂量组，血气指标有一最适剂量（180mg/kg体重）。肺泡-动脉氧分压差（AaDO2)，高、中剂量组均明显低于对照组和低剂量组，两类地区比较，其血气指标均为海拔高的地区明显低于海拔低的地区。结论：增加机体动脉血氧饱和度，是高原康胶囊防治急性高原反应的一个重要机制。     

Altitude-related hypoxia: risk assessment and management for passengers on commerical aircraft

BACKGROUND: Individuals with pulmonary and cardiac disorders are particularly at risk of developing hypoxemia at altitude. Our objective is to describe the normal and maladaptive physiological responses to altitude-related hypoxia, to review existing methods and guidelines for preflight assessment of air travelers, and to provide recommendations for treatment of hypoxia at altitude. DATA SYNTHESIS: Falling partial pressure of oxygen with altitude results in a number of physiologic adaptations including hyperventilation, pulmonary vasoconstriction, altered ventilation/perfusion matching, and increased sympathetic tone. According to three guideline statements, the arterial pressure of oxygen (PaO2) should be maintained above 50 to 55 mm Hg at all altitudes. General indicators such as oxygen saturation and sea level blood gases may be useful in predicting altitude hypoxia. More specialized techniques for estimation of altitude PaO2, such as regression equations, hypoxia challenge testing, and hypobaric chamber exposure have also been examined. A regression equation using sea level PaO2 and spirometric parameters can be used to estimate PaO2 at altitude. Hypoxia challenge testing, performed by exposing subjects to lower inspired FIO2 at sea level may be more precise. Hypobaric chamber exposure, the gold standard, mimics lower barometric pressure, but is mainly used in research. CONCLUSION: Oxygen supplementation during air travel is needed for individuals with an estimated PaO2 (8000 ft) below 50 mmHg. There are a number of guidelines for the pre-flight assessment of patients with pulmonary and/or cardiac diseases. However, these data are based on small studies in patients with a limited group of diseases.     

Time of useful consciousness determination in aircrew members with reference to prior altitude chamber experience and age

BACKGROUND: Hypoxia tolerance has been evaluated by the secondary responses to oxyhemoglobin deoxygenation: the time of useful consciousness (TUC), subjective symptoms, ventilatory responses, and cardiovascular changes. It is not clear whether the deoxygenation rate per se reflects hypoxia tolerance or how it relates to the former parameters. METHODS: In Study 1, we monitored arterial oxygen saturation (SaO2) by pulse oximetry in the nonsmoking subjects experiencing hypoxia at the simulated altitude of 25,000 ft. Male subjects were divided into two groups: junior (< or =39 yr, n = 108) and senior (> or =40 yr, n = 44). The duration from mask-off to mask-on (TUC), the duration from mask-off to the time of SaO2 of 90%(T90), the duration from 90% to 70% of SaO2(T70), and the SaO2 value at mask-on (bottom SaO2) were compared between the two groups. (In a separate, but related study, 10 medical variables were analyzed by stepwise regression to investigate the contributing factors to hypoxia tolerance in 77 other subjects, including 11 female subjects.) In study 2, 12 subjective hypoxic symptoms at 25,000 ft were compared between junior (n = 369) and senior (n = 160) groups. RESULTS: TUC was significantly longer in the junior group, but T70 was longer and bottom SaO2 was higher in the senior group. Age was adopted as a contributing variable in three out of six dependent parameters. Subjective symptoms were in the similar rank order for both groups. CONCLUSION: Pulse oximetry reconfirmed that age is a major influencing factor for acute hypoxia tolerance. This may be due not only to the physiological effect but also to the training experience to recognize hypoxic deterioration more quickly.     

富氧对缺氧大鼠心肌琥珀酸脱氢酶及超微结构的影响

目的：探讨富氧对缺氧大鼠心肌损伤的保护作用及机理。方法：雄性Wistar大鼠32只随机分为平原对照组、低氧组、富氧组，低氧组在模拟海拔5400m低压舱内24h，富氧组在模拟5400m的低压舱内12h，然后富氧（27．0％的氧混合气）12h，观察心肌琥珀酸脱氢酶（SDH）及超微结构的改变。结果：低氧组心肌细胞灶性变性坏死，肌丝溶解凝固，间质水肿液和纤维素样渗出。富氧组心肌无明显病变，仅滑面内质网轻度扩张。富氧组SDH活性明显高于低氧组。结论：低氧导致心肌SDH活性及超微结构的改变，富氧对心肌有保护作用。     

夏季高原军训动脉血气和肺功变化的临床研究

目的探讨部队在高原集训中动脉血气酸碱和肺通气功能变化.方法将由低海拔区进驻高原的青年士兵480例随机分为复方红景天(RadiodaCompoundRCO)防治组(RG),参芪花粉合剂(AstragalusCodonopsisCompoundACO)防治组(AG),安慰合剂组(对照组CG1和CG2)各120例,均于进驻高原前24h分别服用RCO、ACO和安慰合剂.按预设方案分别登记呼吸次数(R)*min-1、脉搏次数(P)*min-1,进驻高原不同梯度(2900m,3200m,3700m,4400m)后依次登记R、P,并按记分标准登记不同梯度的高原反应.同时随机抽测4组的中心动脉血气、肺功、指氧饱和度(SaO2).结果在2900m、3700m、4400m不同海拔梯度PaO2和SaO2呈梯度性下降,但PaCO2呈不稳定上升,脉搏、呼吸次数增快,肺功出现代偿性加强变化.在3700m,4400m两个梯度的PaO2RG比CG1和CG2分别高出4.4mmHg(P＜0.01),3.4mmHg(P＜0.01),各组间其它指标亦有相应的变化趋势.结论高原军事作业过程中PaO2下降明显,pH、PCaO2呈显著不稳定上升状态.预服中药RCO、ACO可增强高原适应性,提高PaO2,降低AHR和ARI发生率,适用于部队群体进驻高原的防护.