模拟微重力或微重力时血容量减少对立位耐力影响的研究进展

航天后立位耐力降低普遍存在,其机理仍不清楚。一般认为血容量减少是航天后立位耐力降低的一个重要因素。现有对抗航天后一耐力降低的措施均与血容量有关。微重力（μＧ）和模拟μＧ时研究表明：μＧ与现有模拟μＧ模型时人体生理学变化的主要差异表现在低压区循环和体液、电解质代谢。细胞外体液主要受心肺反射和适当的模拟μＧ模型研究低压区循环、心肺反射变化的时间过程,对认为立位耐力降低机理和制定更有效的对抗立位耐力降低     

电离辐射对大鼠小肠Na-K-ATP酶活性的影响

Na-K-ATP 酶在小肠粘膜和肾小管上皮等组织中活性较高。它在糖、氨基酸等物质和水及电解质的吸收过程中超重要作用。电离辐射后,出现小肠粘膜吸收功能障碍及水电解质平衡紊乱,为了更好地阐明电离辐射引起这些变化的原因,我们测定了电离辐射后大鼠小肠粘膜的 Na-K-ATP 酶活性的变化。     

体液[Ca++]o变化诱发的心脏起搏细胞兴奋节律的分叉与混沌(Chay模型)

目的探讨航天中体液电解质中[Ca++]o变化对心跳节律的影响.方法应用可兴奋性细胞离子通道最小模型-柴(Chay)模型,以心脏细胞动作电位峰-峰间期(ISI)为研究对象,调节方程中的参数Vc,(与[Ca++]o有关), 观察ISI的变化. 结果 ISI出现周期运动、混沌运动及加周期、倍周期分叉等现象,表明航天中[Ca++]o变化可能会引起心脏起搏细胞兴奋节律的变化,并进而使心跳节律发生相应变化. 结论除心脏活动的神经、体液调节因素作用以外,航天中体液[Ca++]o的变化是引起心脏起搏细胞兴奋节律改变及其心律失常的不可忽视的因素.     

体液[Ca^＋＋]o变化诱发的心脏起搏细胞兴奋节律的分叉与混 …

目的 探讨航天中体液电解质中［Ｃａ＾＋＋］ｏ变化对心跳节律的影响。方法 应用可兴奋性细胞离子通道最小模型－柴（Ｃｈａｙ）模型,以心脏细胞动作电位峰－峰间期（ＩＳＩ）为研究对象,调节方程中的参数Ｖｃ,（与［Ｃａ＾＋＋］ｏ有关）,观察ＩＳＩ的变化。结果ＩＳＩ出现周期运动、混沌运动及加周期、倍周期分叉等现象,表明航天中［Ｃａ＾＋＋］ｏ变化可能会引起心脏起搏细胞兴奋节律的变化,并进而使心跳节律发生相应变化     

微重力条件下人体体液调节模型的分析与改进思考

航天和模拟微重力时研究表明：微重力与现有模拟微重力模型时人体生理学变化的主要差异表现在低压区循环和体液、电解质代谢。微重力生理研究的人体模型在进一步了解微重力对人体的生理影响和机理中不可缺少,有必要将现有人体模拟微重力模型加以改进。利用人体不同角度和不同压力制度的立位倾斜（ＨＵＴ）加下体正压、头低位卧床（ＨＤＴ）加上体负压,测量心血管参数、体液调节因子、肾排泄的有关指标,与航天中的相应指标对照,筛     

急性缺氧对人体血液部分离子浓度的影响

目的通过正常及三种不同缺氧条件下血中Ｎａ＋、Ｃｌ－浓度及ｐＨ值的测定，探索急性缺氧对血电解质平衡的影响。方法１２名健康男性青年通过面罩吸入空气或含氧量为１４．５％、１１．２％、９．８％的氧氮混合气１５ｍｉｎ。采集静脉血，利用电解质分析仪对其中的离子浓度进行测定。结果与自身对照组相比，三种缺氧条件下的Ｎａ＋和Ｃｌ－浓度均显著降低（Ｐ＜０．０１）；ｐＨ值在１４．５％低氧期变化不明显（Ｐ＞０．０５），在１１．２％和９．８％低氧期显著降低（Ｐ＜０．０５）。结论血液中电解质浓度对缺氧变化非常敏感，由此可能引发机体的一系列变化，如酸碱平衡失调、钙平衡失调、血细胞损伤等，这些失调性变化将是航空航天医学监督与保障工作中所不可忽视的问题之一     

烧伤监护与临床处理——第二讲 体液与电解质平衡的监护与处理

本节是为了帮助监护人员澄清对体液与电解质的一些混乱认识而写的,每位烧伤监护人员应懂得烧伤病人最容易发生的体液与电解质异常有哪些,及时补充体液与电解质有何重要意义。对危重病人或有水与电解质平衡失调的患者应详细测量和记录病人的液体出入量,每天称病人体重。钠、钾、钙、镁等离子及水平衡发生异常时的临床表现如何。除了详细观察和记录每个体征或症状之外,     

航天血液学研究进展

航天导致身体多个系统发生改变，其中血液系统的变化也非常明显，主要表现为血浆容量和红细胞数量降低等。早期航天血液学研究多限于观察航天中血液学指标的变化，其机理研究则在近几年得到了较大发展。对失重条件下血液学变化也有了新的认识，发现了红细胞数量快速下调的机制。本文就有关这方面的重要研究作了简要的回顾。     

肠内营养在胃瘫治疗中的作用

目的　探讨肠内营养在治疗胃瘫病人中的效果。方法　通过肠内营养注入系统 ,输入肠内营养制剂观察临床表现 ,营养前后血糖、肝功能、血电解质、血气分析及各营养指标的变化。结果　所有病人均经保守治疗治愈 ,残胃功能恢复较快 ,无感染并发症 ,在治疗过程中血糖、肝肾功能、电解质、血气分析均处于正常范围。体重、血红蛋白、血清总蛋白、白蛋白及氮平衡在营养前后均有明显提高。结论　肠内营养支持能促进残胃功能恢复 ,改善机体营养状况 ,维持水电解质酸碱平衡及肠道正常结构和功能 ,是治疗胃瘫的有效手段     

长期空间飞行中人的作业能力变化特性研究

航天员是载人航天活动的主体和核心,维持和增强航天员的能力,充分发挥人的主观能动作用是确保载人航天任务成功的关键。我国载人航天正从短期向长期空间飞行过渡,研究长期空间飞行下人的作业能力变化特性是开展相关研制的基础。本文从论述载人航天中人的地位和作用出发,分析了长期空间飞行中人的作业能力特点和需求,较系统地综述了国际上在长期空间飞行中人的作业能力变化特性方面最新基础研究和应用成果及发展态势,最后对我国空间站和后续载人航天任务在航天员作业能力方面的研究提出了建议。     

慢粒急变合并高白细胞肿瘤溶解综合征的治疗体会

本文报告一例慢粒急变合并肺部感染患者,入院时有严重贫血、呼吸困难及高血钾、高尿酸、氮质血症及低血钙等肿瘤溶解综合征表现。且白细胞数高达200～300×10~9/L。用利尿补碱,温和化疗,控制感染,调整水、电解质平衡等措施,使病情再次缓解。     

Individual characteristics of water-mineral metabolism during 120-day head-down tilt hypokinesia and the effectiveness of prophylactic measures

Sodium balance and circulating plasma, intracellular, extracellular and interstitial fluid volumes were measured in the test subjects exposed for 120 days to head-down tilt at -5 degrees. The large scatter of the above parameters was associated with individual variations and with the use of different countermeasures against demineralization (exercise and drugs-xydiphone and glucamak). The effect of the countermeasures was different both in qualitative and quantitative terms. It appears that the target of their action was different. The best prophylactic effect was seen when exercise and drugs were used in combination. These findings suggest that individual variations of fluid-electrolyte metabolism during prolonged hypokinesia are related to the different capacity of tissues for water and electrolytes.     

创伤治疗中的内环境调节

严重创伤常会引起机体内环境失衡,直接影响到伤员的预后和疗效.在内环境的调节上可从把握好"3个环节"和协调好"4个平衡"做起,即合理营养支持、体温调控和应用好血管活性药物,做好体液平衡、酸碱平衡、电解质平衡和渗透压平衡.     

环孢霉素A对弥漫性轴索损伤后大鼠神经功能保护的研究

目的　探讨大鼠弥漫性轴索损伤后应用环孢霉素A治疗能否促进大鼠神经功能的恢复。方法　将 2 4只SD大鼠随机均分为正常对照组、损伤对照组和环孢霉素A治疗组 ,制作大鼠弥漫性轴索损伤模型 ,用Morris水迷宫和木梁平衡实验评价大鼠学习记忆能力和综合平衡能力。结果　环孢霉素A治疗后 ,大鼠在木梁上的时间长于损伤对照组 (F =2 75 4 4 ,P <0 0 1 ) ,在连测的 5天内 ,治疗组和损伤对照组行为评分呈下降趋势 ,治疗组平衡能力好于对照组 (F =36 97,P <0 0 1 )。在水迷宫实验中 ,尽管治疗组找到平台的时间和正常对照组相比有所延长 (F=6 9 2 7,P <0 0 1 ) ,但明显少于损伤对照组 (F =1 72 1 0 ,P <0 0 1 )。结论　环孢霉素A能改善大鼠的学习记忆能力和综合平衡能力 ,促进大鼠神经功能的恢复     

我国31个城市饮用水氡浓度初步调查

目的:初步调查我国城市饮用水氡水平、分布特征及其影响因素。方法:按照行政区域采样,选择我国31个省会城市和直辖市,采集市政供水管网末梢水样品406份,基于RAD7 H 2O测量装置,采取闭合回路液—气平衡法,利用抓取模式,通过半导体探测器探测气体回路中氡浓度,经过4个循环周期,推算饮用水氡浓度。 ...     

American College of Sports Medicine position stand. Exercise and fluid replacement

This Position Stand provides guidance on fluid replacement to sustain appropriate hydration of individuals performing physical activity. The goal of prehydrating is to start the activity euhydrated and with normal plasma electrolyte levels. Prehydrating with beverages, in addition to normal meals and fluid intake, should be initiated when needed at least several hours before the activity to enable fluid absorption and allow urine output to return to normal levels. The goal of drinking during exercise is to prevent excessive (>2% body weight loss from water deficit) dehydration and excessive changes in electrolyte balance to avert compromised performance. Because there is considerable variability in sweating rates and sweat electrolyte content between individuals, customized fluid replacement programs are recommended. Individual sweat rates can be estimated by measuring body weight before and after exercise. During exercise, consuming beverages containing electrolytes and carbohydrates can provide benefits over water alone under certain circumstances. After exercise, the goal is to replace any fluid electrolyte deficit. The speed with which rehydration is needed and the magnitude of fluid electrolyte deficits will determine if an aggressive replacement program is merited.     

Water and electrolyte replacement during repeated days of work in the heat.

In an attempt to determine the value of replacing sweat losses with and electrolyte solution, 12 subjects (2 women and 10 men) were dehydrated (minus 3% body weight) on 5 successive days.During one 5-d sequence, the subjects replaced fluid losses with a glucose-electrolyte solution, while water was the only fluid ingested during a second 5-d series. With the exception of the drink, daily ionic and caloric intakes were identical for the two 5-d conditions. Measurements of water and electrolyte losses in sweat and urine showed a positive balance in body Na+, K+, and Cl- during both the water (W) and electrolyte solution (ES) treatments. Subjects accumulated significantly more Na+ during the W experiments (392 mEq/5 d) than when the electrolyte solution was ingested (334 mEq/5 d). As a result, the extracellular fluid compartment, represented by plasma volume, increased 12.2 and 9.0% during the 5-d sequence of the W and ES trials, respectively. It was concluded that the addition of electrolytes to drinking water is of minimal value for subjects who dehydrated (-3%) on repeated days and are permitted to ingest food and drink libitum     

Water and electrolyte requirements for exercise.

Exercise performance can be compromised by a body water deficit, particularly when exercise is performed in hot climates. It is recommended that individuals begin exercise when adequately hydrated. This can be facilitated by drinking 400 mL to 600 mL of fluid 2 hours before beginning exercise and drinking sufficient fluid during exercise to prevent dehydration from exceeding 2% body weight. A practical recommendation is to drink small amounts of fluid (150-300 mL) every 15 to 20 minutes of exercise, varying the volume depending on sweating rate. Core temperature, heart rate, and perceived effort remain lowest when fluid replacement comes closest to matching the rate of sweat loss. During exercise lasting less than 90 minutes, water alone is sufficient for fluid replacement. During prolonged exercise lasting longer than 90 minutes, commercially available carbohydrate electrolyte beverages should be considered to provide an exogenous carbohydrate source to sustain carbohydrate oxidation and endurance performance. Electrolyte supplementation is generally not necessary because dietary intake is adequate to offset electrolytes lost in sweat and urine; however, during initial days of hot-weather training or when meals are not calorically adequate, supplemental salt intake may be indicated to sustain sodium balance.     

运动员快速减体重期水和无机盐代谢及其补充的研究

<正> 在举重、摔跤、柔道等按体重级别进行比赛的项目中,运动员为参加某一体重级别比赛,以取得较好的名次,常常需要在几天内快速减去几公斤体重。这种快速减体重可能造成机体代谢的紊乱,降低运动能力,甚至有碍健