高原低氧环境对人体的影响

高原是指海拔3 000米以上,超过5 800米为特高海拔地区。高原缺氧对机体有一定损害。而高原自然条件对人体最大的影响是低氧环境,机体进入高原后,缺氧可引起各系统机能一系列的应急反应,从而使机体发生暂时性的功能紊乱即“高山反     

进入高原后心功能出现改变的追踪观察

进入高原后心功能出现改变的追踪观察李全会１杜凤兰１孟宪法２（１西安医科大学第一附属医院呼吸科西安７１００６１２大连大学医学院）关键词心脏功能试验；高海拔；健康和疾病高原低氧状态下，心功能改变是人体对低氧生理性适应的一个重要体现。作者对进入高原４８５０...     

进入高原后心功能出现改变的追踪观察

进入高原后心功能出现改变的追踪观察李全会１杜凤兰１孟宪法２（１西安医科大学第一附属医院呼吸科西安７１００６１２大连大学医学院）关键词心脏功能试验；高海拔；健康和疾病高原低氧状态下，心功能改变是人体对低氧生理性适应的一个重要体现。作者对进入高原４８５０...     

高原健康老年人重返平原后心脏收缩功能的变化

高原健康老年人重返平原后心脏收缩功能的变化王小珍吴天一张丽珠孪万寿陈秋红（青海省高原医学科学研究所西宁８１００１２）关键词高海拔心室功能心动描记术老年人人体在高原低氧环境中经过长期的适应，必定产生一系列的生理变化。当重返平原后，低氧刺激消除，将产生新...     

高原临床与血尿酸的关系

高原系指海拔3000m以上，能激发机体产生生物学效应的环境及高度，高原的自然环境具有空气稀薄，寒冷、风大、干燥和日光辐射强的特点，其中空气稀薄、大气压和氧分压低是高原环境影响机体的主要因素。人体进入高原后，受到以低氧、低气压为主的诸多因素的影响，全身各系统从器官水平到分子水平，从功能到组织结构多发生一系列变化，功能改变是指“高山反应”而言，即缺氧引起的各系统功能发生的暂时紊乱，并产生相应的症状，其功能紊乱的程度，相应症状的轻重及持续时间与海拔高度，进入高原时间，季节、活动及个体差异有关。机体为了适应高原环境，从内环境不平衡到平衡，机体发生一系列改变，从而引起高原疾病。     

西藏不同海拔世居藏族居民上消化道黏膜大体形态观察

当攻击因素与防御因素失衡时，上消化道黏膜的结构将被破坏，从而引起系列黏膜病变。西藏地区高海拔因素，尤其是高原缺氧对人体心肺产生巨大影响，而该因素对人体上消化道黏膜大体形态有何影响，目前知之甚少。本研究选择遗传、饮食结构、生活习惯一致的世居高低海拔藏族居民，分析胃镜检查结果，探讨西藏高海拔因素对人胃黏膜大体形态的影响。     

世居青藏高原的藏族与汉族健康男性青年心肺功能比较

<正>青藏高原环境的特点是氧分压低、空气稀薄、昼夜温差大、紫外线强,其中氧分压低是影响人体肺功能的最主要因素。而世居青藏高原的藏族人群对高原低氧环境有着良好的适应能力,也是人类对高原的最佳适应模式〔1〕。以往研究表明,心肺功能是人类习服高原低氧环境的关键〔2〕。本研究探讨世居青藏高原的藏族与汉族健康男性青年心肺功能的差异。1资料和方法1.1一般资料平均海拔为(2 970.83±333.96)m、父母均为     

高原低氧环境P波微细变化的动态观察及其个体差异

高原低氧环境Ｐ波微细变化的动态观察及其个体差异李全会，李永寿，石志红，孟宪法，匡延龄（西安医科大学第一附属医院西安７１００６１青海省西宁市解放军第４医院青海医学院高原生理学教研室西宁８１００１４）人体移居高原，在习服过程中必然引起心肺功能相应的变化。...     

海拔梯度对健康人血管活性物质的影响

近年研究表明,在影响高原人体健康的诸多因素中,低氧环境是最重要的因素.2006年5月～2007年10月,我们通过检测不同海拔高度健康男性血管活性物质的水平,探讨高原慢性缺氧对人体的影响.现报告如下.     

高原脑水肿64例护理体会

高原脑水肿是急性高原病中的危重型，是人进入高原或急进至更高海拔地区后，由于高原缺氧引起的脑功能障碍，多发生在海拔3000m以上的地区，如不及时积极有效救治，病死率极高。我院驻地海拔约3900m，高原脑水肿是我科常见的危重症之一，护理难度大，笔者对近8年来我科救治的64例高原脑水肿患者的护理进行了系统回顾，现报告如下。     

缺氧和促红细胞生成素对线粒体影响的研究进展

缺氧是高原环境的一大特点之一,缺氧对机体的损伤主要与线粒体的功能有关。同时在缺氧条件下,促红细胞生成素代偿性增加,并可对线粒体的功能产生一定的影响。本文对缺氧和促红细胞生成素对线粒体影响的研究现状予以综述。     

Comparative human ventilatory adaptation to high altitude

Studies of ventilatory response to high altitudes have occupied an important position in respiratory physiology. This review summarizes recent studies in Tibetan high-altitude residents that collectively challenge the prior consensus that lifelong high-altitude residents ventilate less than acclimatized newcomers do as the result of acquired 'blunting' of hypoxic ventilatory responsiveness. These studies indicate that Tibetans ventilate more than Andean high-altitude natives residing at the same or similar altitudes (PET[CO(2)]) in Tibetans=29.6+/-0.8 vs. Andeans=31.0+/-1.0, P<0.0002 at approximately 4200 m), a difference which approximates the change that occurs between the time of acute hypoxic exposure to once ventilatory acclimatization has been achieved. Tibetans ventilate as much as acclimatized newcomers whereas Andeans ventilate less. However, the extent to which differences in hypoxic ventilatory response (HVR) are responsible is uncertain from existing data. Tibetans have an HVR as high as those of acclimatized newcomers whereas Andeans generally do not, but HVR is not consistently greater in comparisons of Tibetan versus Andean highland residents. Human and experimental animal studies demonstrate that inter-individual and genetic factors affect acute HVR and likely modify acclimatization and hyperventilatory response to high altitude. But the mechanisms responsible for ventilatory roll-off, hyperoxic hyperventilation, and acquired blunting of HVR are poorly understood, especially as they pertain to high-altitude residents. Developmental factors affecting neonatal arterial oxygenation are likely important and may vary between populations. Functional significance has been investigated with respect to the occurrence of chronic mountain sickness and intrauterine growth restriction for which, in both cases, low HVR seems disadvantageous. Additional studies are needed to address the various components of ventilatory control in native Tibetan, Andean and other lifelong high-altitude residents to decide the factors responsible for blunting HVR and diminishing ventilation in some native high-altitude residents.     

PDGF在高原性肺动脉高压大鼠肺动脉中的表达及波生坦对其表达的影响

目的:观察低氧性肺血管重建(HPSR)中肺动脉平滑肌增生性改变,探讨波生坦(BST)对高原性肺动脉高压(HAEPH)的逆转作用及对HAEPH大鼠肺动脉血小板源性生长因子(PDGF)表达的影响。方法:采用全自动调节的低压低氧舱模拟海拔5 000~5 500 m高度的气压环境(大气压约50 kPa),建立慢性HAEPH大鼠模型。将40只SD大鼠随机分为4组:对照组、模型组、安慰剂组和BST组,每组各10只。对照组常压常氧下饲养6周,其他3组均置于低压低氧仓中进行间断低氧(8 h/d),并分别饲养3周、6周、6周。自第4周起,安慰剂组和BST组大鼠在入仓前分别给予生理盐水(2 ml)和BST(100 mg/kg)灌胃。6周后取肺组织石蜡包埋,连续切片后,观察肺血管形态学变化。用免疫组织化学染色法对各组大鼠肺动脉中PDGF的表达进行定位及半定量分析。结果:①安慰剂组大鼠的肺动脉管壁增厚、管腔狭窄,BST组大鼠的肺动脉管壁厚度及管腔恢复至正常组状态。②各组大鼠肺动脉均有PDGF表达,随低氧时间的延长,PDGF的表达逐渐增加,BST组PDGF的表达与正常组比较无统计学差异。结论:①BST可有效地逆转HPSR,提示BST对HAEPH具有治疗作用。②BST对HAEPH大鼠肺动脉中PDGF的表达具有抑制作用。     

Acute Mountain Sickness: Pathophysiology, Prevention, and Treatment

Barometric pressure falls with increasing altitude and consequently there is a reduction in the partial pressure of oxygen resulting in a hypoxic challenge to any individual ascending to altitude. A spectrum of high altitude illnesses can occur when the hypoxic stress outstrips the subject's ability to acclimatize. Acute altitude-related problems consist of the common syndrome of acute mountain sickness, which is relatively benign and usually self-limiting, and the rarer, more serious syndromes of high-altitude cerebral edema and high-altitude pulmonary edema. A common feature of acute altitude illness is rapid ascent by otherwise fit individuals to altitudes above 3000 m without sufficient time to acclimatize. The susceptibility of an individual to high-altitude syndromes is variable but generally reproducible. Prevention of altitude-related illness by slow ascent is the best approach, but this is not always practical. The immediate management of serious illness requires oxygen (if available) and descent of more than 300 m as soon as possible. In this article, we describe the setting and clinical features of acute mountain sickness and high-altitude cerebral edema, including an overview of the known pathophysiology, and explain contemporary practices for both prevention and treatment exploring the comprehensive evidence base for the various interventions.     

Human ecological cardiology]

Human ecological cardiology studies the interaction of the cardiovascular system and its regulating apparatus with the natural environment to clarify their morpho-functional formation, the mechanisms of the development of disorders and their adequate correction and the use of this natural environment for therapeutic and prophylactic purposes. Problems of adaptation of the cardiovascular system to extreme environmental conditions (high-altitude hypoxia) are discussed. Four groups of trace reactions in adaptation to the environment are described. High-altitude pathology of the cardiovascular system is systemized.     

EGLN1 involvement in high-altitude adaptation revealed through genetic analysis of extreme constitution types defined in Ayurveda

It is being realized that identification of subgroups within normal controls corresponding to contrasting disease susceptibility is likely to lead to more effective predictive marker discovery. We have previously used the Ayurvedic concept of Prakriti, which relates to phenotypic differences in normal individuals, including response to external environment as well as susceptibility to diseases, to explore molecular differences between three contrasting Prakriti types: Vata, Pitta, and Kapha. EGLN1 was one among 251 differentially expressed genes between the Prakriti types. In the present study, we report a link between high-altitude adaptation and common variations rs479200 (C/T) and rs480902 (T/C) in the EGLN1 gene. Furthermore, the TT genotype of rs479200, which was more frequent in Kapha types and correlated with higher expression of EGLN1, was associated with patients suffering from high-altitude pulmonary edema, whereas it was present at a significantly lower frequency in Pitta and nearly absent in natives of high altitude. Analysis of Human Genome Diversity Panel-Centre d'Etude du Polymorphisme Humain (HGDP-CEPH) and Indian Genome Variation Consortium panels showed that disparate genetic lineages at high altitudes share the same ancestral allele (T) of rs480902 that is overrepresented in Pitta and positively correlated with altitude globally (P < 0.001), including in India. Thus, EGLN1 polymorphisms are associated with high-altitude adaptation, and a genotype rare in highlanders but overrepresented in a subgroup of normal lowlanders discernable by Ayurveda may confer increased risk for high-altitude pulmonary edema.     

The treatment of hypertension by adaptation to high-altitude hypoxia]

Ethnically close male populations aged 30-59 years who reside in high mountains (2800-3600 m above the sea level) and in low lands (800-900 m above the sea level) of the Tien Shan and the Pamirs were screened. The incidence of essential hypertension was found to be significantly lower (4.2%) among the highlanders than in the lowlanders (15.4%). In highlanders, hypertension is characterized by a high concurrence with high-altitude arterial hypertension and right ventricular hypertrophy. Daily urinary aldosterone excretion is substantially lower in residents of high mountains and natriuresis is higher than that in those from low-lands. Sixty-eight patients with mild hypertension took daily treatment as pressure chamber uplifting (3200 m above the sea level; pO2 112 mm Hg) for 15 days and 45 patients with moderate hypertension were treated with medium-land (1600 m; pO2 134 mm Hg) adaptation for 24 days. Pressure chamber hypoxic training and medium-land adaptation in 69% of patients with mild hypertension and 64.4% with moderate hypertension without signs of target organ lesions produced steady antihypertensive effects, a steady-state (for a 1.5-year follow-up) decrease in cardiac mechanical work, peripheral vascular resistance, arterial impedance, and an improvement of physical fitness. It was proposed to use hypoxic (pressure chamber and high-altitude) training for the treatment of early hypertensive disease and its secondary prevention.     

On the rapidity of antibiotic resistance evolution facilitated by a concentration gradient

The rapid emergence of bacterial strains resistant to multiple antibiotics is posing a growing public health risk. The mechanisms underlying the rapid evolution of drug resistance are, however, poorly understood. The heterogeneity of the environments in which bacteria encounter antibiotic drugs could play an important role. E.g., in the highly compartmentalized human body, drug levels can vary substantially between different organs and tissues. It has been proposed that this could facilitate the selection of resistant mutants, and recent experiments support this. To study the role of spatial heterogeneity in the evolution of drug resistance, we present a quantitative model describing an environment subdivided into relatively isolated compartments with various antibiotic concentrations, in which bacteria evolve under the stochastic processes of proliferation, migration, mutation and death. Analytical and numerical results demonstrate that concentration gradients can foster a mode of adaptation that is impossible in uniform environments. It allows resistant mutants to evade competition and circumvent the slow process of fixation by invading compartments with higher drug concentrations, where less resistant strains cannot subsist. The speed of this process increases sharply with the sensitivity of the growth rate to the antibiotic concentration, which we argue to be generic. Comparable adaptation rates in uniform environments would require a high selection coefficient (s > 0.1) for each forward mutation. Similar processes can occur if the heterogeneity is more complex than just a linear gradient. The model may also be applicable to other adaptive processes involving environmental heterogeneity and range expansion.