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。     

拉萨健康藏汉族成人低氧通气反应及肺通气功能比较研究

对海拔３６５８ｍ高原（拉萨）２７名拉萨世居藏族及３０名已习服的移居汉族两组的低氧通气反应（ＨＶＲ）和肺通气功能进行了比较研究。两组的年龄、身高、体重和平时运动强度基本相同。结果显示：世居组的每分钟气量（ＶＥ）,呼吸频率、ＨＶＲ和高二氧化碳通气反应（ＨＣＶＲ）均高于移居组,两组的ＰＥＴＣＯ２及Ｓａｏ２无显著性差异;吸入高浓度Ｏ２后,世居组的ＶＥ增加,ＰＥＴＣＯ２下降,而移居组维持不变。结果表明高原世     

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...     

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.     

世居及移居高原青少年最大有氧能力的特征

本文报道海拔３４１７ｍ和４２８０ｍ地区世居藏族和移居汉族青少年运动状态下心肺功能的对比研究。结果显示：３４１７ｍ和４２８０ｍ世居藏族的最大氧耗量、无氧阈值及最大心输出量都明显大于汉族,血氧饱和度（Ｓａｏ２）随运动负荷的增加而降低。海拔３４１７ｍ藏、汉族的△Ｓａｏ２分别为７．４６％和１０．０３％,４２８０ｍ处为８．５７％和１３．７５％,最大心率随海拔升高而下降。研究提示,藏族青少年有较高的最大有氧能力,反映了他们对低氧环境的适应优势。     

颜色明度辨别阈限的高海拔效应北大核心CSCD

高海拔低氧环境暴露广泛影响人类中枢神经系统。以往高海拔低氧环境影响人类颜色感知的研究集中于模拟高海拔环境和急性暴露于高海拔环境,鲜有对长期暴露于高海拔低氧环境的移居者和世居者的研究。本研究采用最小变化法比较汉族平原居住者(30名)、汉族移居高海拔区时间满2年者(30名)、高海拔藏族世居者(28名)的红、绿、蓝、黄4种颜色的明度差别阈限,观察其受海拔环境的影响。结果显示,长期高海拔暴露对世居者和移居者的蓝色和红色差别阈限影响最显著,对蓝色差别阈限影响显著大于红色,而对绿色差别阈限产生的影响仅发生于世居者。研究提示,血液供应量与高原环境暴露导致视觉颜色加工选择性改变有内在的关联。     

颜色明度辨别阈限的高海拔效应

高海拔低氧环境暴露广泛影响人类中枢神经系统。以往高海拔低氧环境影响人类颜色感知的研究集中于模拟高海拔环境和急性暴露于高海拔环境,鲜有对长期暴露于高海拔低氧环境的移居者和世居者的研究。本研究采用最小变化法比较汉族平原居住者(30名)、汉族移居高海拔区时间满2年者(30名)、高海拔藏族世居者(28名)的红、绿、蓝、黄4种颜色的明度差别阈限,观察其受海拔环境的影响。结果显示,长期高海拔暴露对世居者和移居者的蓝色和红色差别阈限影响最显著,对蓝色差别阈限影响显著大于红色,而对绿色差别阈限产生的影响仅发生于世居者。研究提示,血液供应量与高原环境暴露导致视觉颜色加工选择性改变有内在的关联。     

高原红细胞增多症患者红细胞二磷酸甘油酸和氧亲和力变…

在海拔４３００地区,对１８名移居汉族、２４名世居藏族和２１名高原红细胞增多症（ＨＡＰＣ）患者测定了２,３－二磷酸甘油酸（２,３－ＤＰＧ）和肺通气功能,并进行了血气分析。结果显示：ＨＡＰＣ患者的全血和红细胞内２,３－ＤＰＧ深度均显著高于健康组,但世居、移居健康组之间无明显差异。ＨＡＰＣ组的红细胞２,３－ＤＰＧ和Ｐａｏ２呈显著负相关（ｒ＝－０．７７１,Ｐ＜０．０１）,而在健康组无显著相关（ｒ＝－０＼２     

拉萨健康藏汉族青年运动时颈内动脉血流速度的变化

应用多普勒超声法测定了拉萨市１５名健康男性世居藏族和１１名健康男性移居汉族静息时的颈内动脉平均血流速度（ＩＣＡＭＦＶ）;以了解高原居民运动时ＩＣＡＭＦＶ、脑血流（ＣＢＦ）和脑氧供应量的状况。结果表明：静息时两组ＩＣＡＭＦＶ、ＣＢＦ及脑氧供应量相似;次极量运动时,两组的ＩＣＡＭＦＶ和脑氧供应量均增加;但在最大运动负荷时,仅世居组的ＩＣＡＭＦＶ及脑氧供应量增加。ＩＣＡＭＦＶ的增加可代偿最大运动时因ＳａＯ２降低所致的脑氧供应量下降。最大运动时世居组的脑氧供应量高于移居组,主要以ＣＢＦ增加同时与维持较高的ＳａＯ２有关。脑氧供应量的增加可能与提高最大运动负荷能力有关。结果说明长期居住于高原的世居人和移居人运动时ＣＢＦ反应己恢复到与平原相似的正常状态。     

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     

Increased vital and total lung capacities in Tibetan compared to Han residents of Lhasa (3,658 m).

Larger chest dimensions and lung volumes have been reported for Andean high-altitude natives compared with sea-level residents and implicated in raising lung diffusing capacity. Studies conducted in Nepal suggested that lifelong Himalayan residents did not have enlarged chest dimensions. To determine if high-altitude Himalayans (Tibetans) had larger lung volumes than acclimatized newcomers (Han "Chinese"), we studied 38 Tibetan and 43 Han residents of Lhasa, Tibet Autonomous Region, China (elevation 3,658 m) matched for age, height, weight, and smoking history. The Tibetan compared with the Han subjects had a larger total lung capacity [6.80 +/- 0.19 (mean +/- SEM) vs 6.24 +/- 0.18 l BTPS, P less than 0.05], vital capacity (5.00 +/- 0.08 vs 4.51 +/- 0.10 1 BTPS, P less than 0.05), and tended to have a greater residual volume (1.86 +/- 0.12 vs 1.56 +/- 0.09 1 BTPS, P less than 0.06). Chest circumference was greater in the Tibetan than the Han subjects (85 +/- 1 vs 82 +/- 1 cm, P less than 0.05) and correlated with vital capacity in each group as well as in the two groups combined (r = 0.69, P less than 0.05). Han who had migrated to high altitude as children (less than or equal to 5 years old, n = 6) compared to Han adult migrants (greater than or equal to 18 years old, n = 26) were shorter but had similar lung volumes and capacities when normalized for body size. The Tibetans' vital capacity and total lung capacity in relation to body size were similar to values reported previously for lifelong residents of high altitude in South and North America. Thus, Tibetans, like North and South American high-altitude residents, have larger lung volumes. This may be important for raising lung diffusing capacity and preserving arterial oxygen saturation during exercise.     

Internal carotid arterial flow velocity during exercise in Tibetan and Han residents of Lhasa (3,658 m).

Cerebral blood flow increases with acute exposure to high altitude, but the effect of hypoxia on the cerebral circulation at rest and during exercise appears influenced by the duration of high-altitude exposure. To determine whether internal carotid artery flow velocity increased with exercise in long-term residents of high altitude and whether resting values and the response to exercise differed in lifelong vs. acclimatized newcomer male residents of high altitude, we studied 15 native Tibetan and 11 Han ("Chinese") 6 +/- 2-yr residents of Lhasa (3,658 m), Tibet Autonomous Region, China. Noninvasive Doppler ultrasound was used to measure internal carotid artery diameter, mean flow velocity, and, in combination, hemoglobin and arterial O2 saturation to assess cerebral O2 delivery. Tibetan and Han groups were similar in body size and resting internal carotid artery diameter, blood pressure, hemoglobin concentration, internal carotid artery mean flow velocity, and calculated cerebral O2 delivery. Submaximal exercise increased internal carotid artery mean flow velocity and cerebral O2 delivery in the Tibetan and Han subjects. At peak exercise, the Tibetans sustained the increase in flow velocity and cerebral O2 delivery, whereas the Hans did not. Across all exercise levels up to and including peak effort, the Tibetans demonstrated a greater increase in internal carotid artery flow velocity and cerebral O2 delivery relative to resting values than did the Hans. The greater cerebral O2 delivery was accompanied by increased peak exercise capacity in the Tibetan compared with the Han group. Our findings suggest that the cerebral blood flow response to exercise is maintained in Tibetan lifelong residents of high altitude.     

Body structure and respiratory efficiency among high altitude Himalayan populations

To understand the morphological and physiological variations among the temporary and permanent residents of high altitude, this study was undertaken at Leh, Ladakh. It is situated at 3500 m (11500 feet) above sea level, the mean barometric pressure was 500 tors and air temperature varied from 2 degrees C to 20 degrees C. The highland Tibetans showed broadest chest and most developed musculature closely followed by Ladakhi Bods. These high altude natives also displayed significantly higher value of vital capacity, forced vital capacity, and inspiratory capacity. The better respiratory efficiency observed among high altitude residents indicates higher degree of adaptation to high altitude hypoxia. Temporary residents were observed to be tallest and fattest with lower trunk fat predominance of all the four groups and showed narrowest chest and lower respiratory efficiency as compared to high altitude natives. The duration of stay at high altitude has clearly brought about a perceptible difference in body dimensions and respiratory functions of various groups of adult males studied at same altitude.     

Developmental and genetic components explain enhanced pulmonary volumes of female peruvian Quechua

High altitude natives have enlarged vital capacities and residual volumes (RV). Because pulmonary volumes are an indication of functionally relevant traits, such as diffusion capacity, the understanding of the factors (genetic/developmental) that influence lung volumes provides insight into the adaptive responses of highlanders. In order to test for the effect of growth and development at high altitude on lung volumes, we obtained forced vital capacities (FVC), RV, and total lung capacities (TLC) for a sample of 65 Peruvian females of mostly Quechua origins (18-34 years) who were sub-divided into two well-matched groups: 1) sea-level born and raised females (BSL, n = 34) from Lima, Peru (150 m), and 2) high-altitude born and raised females (BHA, n = 31) from Cerro de Pasco, Peru (4,338 m). To determine Quechua origins, Native American ancestry proportion (NAAP) for each individual was assessed using a panel of 70 ancestry informative markers. NAAP was similar between groups (BSL = 91.71%; BHA = 89.93%; P = 0.240), and the analysis confirmed predominantly Quechua origins. After adjusting for body size and NAAP, BHA females had significantly higher FVC (3.79 ± 0.06 l; P < 0.001), RV (0.98 ± 0.03 l; P < 0.001) and TLC (4.80 ± 0.07 l; P < 0.001) compared to BSL females (FVC = 3.33 ± 0.05 l; RV = 0.69 ± 0.03 l; TLC = 4.02 ± 0.06 l). NAAP was not associated with FVC (P = 0.352) or TLC (P = 0.506). However, NAAP was positively associated with RV (P = 0.004). In summary, results indicate that developmental exposure to high altitude in females constitutes an important factor for all lung volumes, whereas both genetic and developmental factors seem to be important for RV.     

海拔对儿童和青少年生长发育的影响

为进一步探讨自然环境因素对生长发育的影响,本文收集了14个省会城市1996年以来7-18岁107986(男56300,女51686)儿童青少年的身高、体重、胸围资料及体质测量当年的海拔、年降水量、年均气温和年日照时数资料,做海拔等自然环境因素与发育指标的Z-分数和发育分相关与回归分析。结果表明,从低海拔组到中海拔组、高海拔组,儿童青少年的生长发育指标逐步下降,其中体重与BMI有统计学意义(P0.05),低海拔组发育指标明显好于高海拔组;生长发育水平与海拔的相关系数大于年均气温和日照时数,与年降水量不相关;回归分析表明海拔每增加1000m,身高、体重、胸围和BMI分别减少0.112,0.101,0.043和0.118个Z-分数。在四项自然环境因素中,海拔对生长发育的影响最大,对身高、体重、胸围和BMI的贡献率分别是28.0%,26.8%,12.0%,16.8%。     

Hemoglobin levels in Qinghai-Tibet: different effects of gender for Tibetans vs. Han.

The Tibetan population, long a resident on the Qinghai-Tibetan Plateau, has lower hemoglobin concentrations than Han Chinese migrants, but it is incompletely known how gender affects the hemoglobin concentrations in the two populations at various altitudes. Measurements of hemoglobin concentration were obtained in 5,887 healthy male and female Tibetan and Han residents aged 5-60 yr, at altitudes of 2,664, 3,813, 4,525, and 5,200 m. Multiple regression equations showed the beta-coefficients for altitude and for age were higher (P < 0.05) in Han men than in Tibetan men and in Han women than in Tibetan women. Analysis indicated a significant three-way interaction between altitude, gender, and ethnicity (chi2 = 3.72, P = 0.05). With increasing altitude, men progressively had more hemoglobin than women in the Han, but not the Tibetan, population. Above 2,664 m, this gender-related difference in hemoglobin concentration increased from childhood to young adulthood more in Han than in Tibetans. We suggest that the Han-Tibetan ethnic difference in the effect of altitude on hemoglobin concentration depends to a large extent on gender.     

Nitric oxide in adaptation to altitude

This review summarizes published information on the levels of nitric oxide gas (NO) in the lungs and NO-derived liquid-phase molecules in the acclimatization of visitors newly arrived at altitudes of 2500 m or more and adaptation of populations whose ancestors arrived thousands of years ago. Studies of acutely exposed visitors to high altitude focus on the first 24-48 h with just a few extending to days or weeks. Among healthy visitors, NO levels in the lung, plasma, and/or red blood cells fell within 2h, but then returned toward baseline or slightly higher by 48 h and increased above baseline by 5 days. Among visitors ill with high-altitude pulmonary edema at the time of the study or in the past, NO levels were lower than those of their healthy counterparts. As for highland populations, Tibetans had NO levels in the lung, plasma, and red blood cells that were at least double and in some cases orders of magnitude greater than other populations regardless of altitude. Red blood cell-associated nitrogen oxides were more than 200 times higher. Other highland populations had generally higher levels although not to the degree shown by Tibetans. Overall, responses of those acclimatized and those presumed to be adapted are in the same direction, although the Tibetans have much larger responses. Missing are long-term data on lowlanders at altitude showing how similar they become to the Tibetan phenotype. Also missing are data on Tibetans at low altitude to see the extent to which their phenotype is a response to the immediate environment or expressed constitutively. The mechanisms causing the visitors' and the Tibetans' high levels of NO and NO-derived molecules at altitude remain unknown. Limited data suggest processes including hypoxic upregulation of NO synthase gene expression, hemoglobin-NO reactions, and genetic variation. Gains in understanding will require integrating appropriate methods and measurement techniques with indicators of adaptive function under hypoxic stress.     

Lung volumes, mechanics, and single-breath diffusing capacity in anesthetized cats.

We measured lung weight, lung volumes, pulmonary mechanics, and carbon monoxide transfer (DLCO, single-breath method) in healthy cats (3.3 +/- 0.4 kg) that were anesthetized, paralyzed, and mechanically ventilated through a tracheal cannula. Compared with Stahl's predicted values which were based on regression analyses of data collected from several species, our cats had larger and more compliant lungs in relation to body weight, higher DLCO per unit body weight, and similar DLCO/TLC (size independent constant). Compared with Robinson et al.'s values derived entirely from studies on dogs, our cats had significantly smaller lung volumes and DLCO per unit body weight, DLCO/TLC and similar ratios of CL/FRC. Several factors appear to contribute to the functional variations among mammalian species: differences in the relation of lung to body weight, differences in the relation of chest wall compliance to lung compliance, and differences in the fundamental structure and design of the respiratory systems. Differences in methodology are acknowledged to be an additional factor.     

Features of glossopharyngeal breathing in breath-hold divers.

One technique employed by competitive breath-hold divers to increase diving depth is to hyperinflate the lungs with glossopharyngeal breathing (GPB). Our aim was to assess the relationship between measured volume and pressure changes due to GPB. Seven healthy male breath-hold divers, age 33 (8) [mean (SD)] years were recruited. Subjects performed baseline body plethysmography (TLC(PRE)). Plethysmography and mouth relaxation pressure were recorded immediately following a maximal GPB maneuver at total lung capacity (TLC) (TLC(GPB)) and within 5 min after the final GPB maneuver (TLC(POST)). Mean TLC increased from TLC(PRE) to TLC(GPB) by 1.95 (0.66) liters and vital capacity (VC) by 1.92 (0.56) liters (P < 0.0001), with no change in residual volume. There was an increase in TLC(POST) compared with TLC(PRE) of 0.16 liters (0.14) (P < 0.02). Mean mouth relaxation pressure at TLC(GPB) was 65 (19) cmH(2)O and was highly correlated with the percent increase in TLC (R = 0.96). Breath-hold divers achieve substantial increases in measured lung volumes using GPB primarily from increasing VC. Approximately one-third of the additional air was accommodated by air compression.     

Differences in mtDNA whole sequence between Tibetan and Han populations suggesting adaptive selection to high altitude

We performed a mitochondrial whole-genome comparison study in 40 Tibetan and 50 Han Chinese. All subjects could be classified into 13 haplogroups pertained to the Macrohaplogroup M and N that pitched different quadrants by principal component analysis. We observed a difference in the M9 haplogroup and identified 18 significant variants by comparing whole sequences between Tibetan and Han populations. Variants in ND2, COX2, tRNA alanine and 12S rRNA were predicted to confer increased protein stability in Tibetans. We compared the base substitutions of nonsynonymous (NS) versus synonymous (S) of 13 protein-encoding genes and found the NS/S values of the ATP6, ATP8, and Cyt b genes were larger (>1) in Tibetans than that in Han population. Our findings provide clues for the existence of adaptive selection for the ATP6, ATP8, Cyt b, ND2, COX2, tRNA alanine and 12S rRNA genes in Tibetans which likely contributed to adaptation to their specific geographic environment, such as high altitude.