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Sample records for high altitude hypoxia

  1. Aging, Tolerance to High Altitude, and Cardiorespiratory Response to Hypoxia.

    PubMed

    Richalet, Jean-Paul; Lhuissier, François J

    2015-06-01

    Richalet, Jean-Paul, and François J. Lhuissier. Aging, tolerance to high altitude, and cardiorespiratory response to hypoxia. High Alt Med Biol. 16:117-124, 2015.--It is generally accepted that aging is rather protective, at least at moderate altitude. Some anecdotal reports even mention successful ascent of peaks over 8000 m and even Everest by elderly people. However, very few studies have explored the influence of aging on tolerance to high altitude and prevalence of acute high altitude related diseases, taking into account all confounding factors such as speed of ascent, altitude reached, sex, training status, and chemo-responsiveness. Changes in physiological responses to hypoxia with aging were assessed through a cross-sectional 20-year study including 4675 subjects (2789 men, 1886 women; 14-85 yrs old) and a longitudinal study including 30 subjects explored at a mean 10.4-year interval. In men, ventilatory response to hypoxia increased, while desaturation was less pronounced with aging. Cardiac response to hypoxia was blunted with aging in both genders. Similar results were found in the longitudinal study, with a decrease in cardiac and an increase in ventilatory response to hypoxia with aging. These adaptive responses were less pronounced or absent in post-menopausal untrained women. In conclusion, in normal healthy and active subjects, aging has no deleterious effect on cardiac and ventilatory responses to hypoxia, at least up to the eighth decade. Aging is not a contraindication for high altitude, as far as no pathological condition interferes and physical fitness is compatible with the intensity of the expected physical demand of one's individual. Physiological evaluation through hypoxic exercise testing before going to high altitude is helpful to detect risk factors of severe high altitude-related diseases.

  2. [A review of drug metabolism under hypoxia environment at high altitude].

    PubMed

    Zhang, Juan-ling; Li, Xiang-yang

    2015-09-01

    The special environmental features of high altitude, such as hypobaric hypoxia, low temperature, arid, high solar radiation, variable climate and geochemical anomaly, cause great effects on human physiology and health. It will provide valuable references and new ideas to study drug's metabolism in special environment of high altitude hypoxia, and give the guidance to clinical reasonable medication, avoiding adverse reactions and personalized medicine in plateau areas. This article reviewed the effect of high altitude hypoxia on drug metabolism, elaborated metabolic characteristics of some drugs and the activity and expression of drug metabolism enzymes under hypoxia environment at high altitude, and discussed related mechanism.

  3. [A review of drug metabolism under hypoxia environment at high altitude].

    PubMed

    Zhang, Juan-ling; Li, Xiang-yang

    2015-09-01

    The special environmental features of high altitude, such as hypobaric hypoxia, low temperature, arid, high solar radiation, variable climate and geochemical anomaly, cause great effects on human physiology and health. It will provide valuable references and new ideas to study drug's metabolism in special environment of high altitude hypoxia, and give the guidance to clinical reasonable medication, avoiding adverse reactions and personalized medicine in plateau areas. This article reviewed the effect of high altitude hypoxia on drug metabolism, elaborated metabolic characteristics of some drugs and the activity and expression of drug metabolism enzymes under hypoxia environment at high altitude, and discussed related mechanism. PMID:26757541

  4. Stability of heartbeat interval distributions in chronic high altitude hypoxia.

    PubMed

    Meyer, M; Rahmel, A; Marconi, C; Grassi, B; Cerretelli, P; Skinner, J E

    1998-01-01

    Recent studies of nonlinear dynamics of the long-term variability of heart rate have identified nontrivial long-range correlations and scale-invariant power-law characteristics (l/f noise) that were remarkably consistent between individuals and were unrelated to external or environmental stimuli (Meyer et al., 1998a). The present analysis of complex nonstationary heartbeat patterns is based on the sequential application of the wavelet transform for elimination of local polynomial nonstationary behavior and an analytic signal approach by use of the Hilbert transform (Cumulative Variation Amplitude Analysis). The effects of chronic high altitude hypoxia on the distributions and scaling functions of cardiac intervals over 24 hr epochs and 4 hr day/nighttime subepochs were determined from serial heartbeat interval time series of digitized 24 hr ambulatory ECGs recorded in 9 healthy subjects (mean age 34 yrs) at sea level and during a sojourn at high altitude (5,050 m) for 34 days (Ev-K2-CNR Pyramid Laboratory, Sagarmatha National Park, Nepal). The results suggest that there exists a hidden, potentially universal, common structure in the heterogeneous time series. A common scaling function with a stable Gamma distribution defines the probability density of the amplitudes of the fluctuations in the heartbeat interval time series of individual subjects. The appropriately rescaled distributions of normal subjects at sea level demonstrated stable Gamma scaling consistent with a single scaled plot (data collapse). Longitudinal assessment of the rescaled distributions of the 24 hr recordings of individual subjects showed that the stability of the distributions was unaffected by the subject's exposure to a hypobaric (hypoxic) environment. The rescaled distributions of 4 hr subepochs showed similar scaling behavior with a stable Gamma distribution indicating that the common structure was unequivocally applicable to both day and night phases and, furthermore, did not undergo

  5. "Omics" of High Altitude Biology: A Urinary Metabolomics Biomarker Study of Rats Under Hypobaric Hypoxia.

    PubMed

    Koundal, Sunil; Gandhi, Sonia; Kaur, Tanzeer; Mazumder, Avik; Khushu, Subash

    2015-12-01

    High altitude medicine is an emerging subspecialty that has crosscutting relevance for 21(st) century science and society: from sports medicine and aerospace industry to urban and rural communities living in high altitude. Recreational travel to high altitude has also become increasingly popular. Rarely has the biology of high altitude biology been studied using systems sciences and omics high-throughput technologies. In the present study, 1H-NMR-based metabolomics, along with multivariate analyses, were employed in a preclinical rat model to characterize the urinary metabolome under hypobaric hypoxia stress. Rats were exposed to simulated altitude of 6700 m above the sea level. The urine samples were collected from pre- and post-exposure (1, 3, 7, and 14 days) of hypobaric hypoxia. Metabolomics urinalysis showed alterations in TCA cycle metabolites (citrate, α-ketoglutarate), cell membrane metabolism (choline), gut micro-flora metabolism (hippurate, phenylacetylglycine), and others (N-acetyl glutamate, creatine, taurine) in response to hypobaric hypoxia. Taurine, a potential biomarker of hepatic function, was elevated after 3 days of hypobaric hypoxia, which indicates altered liver functioning. Liver histopathology confirmed the damage to tissue architecture due to hypobaric hypoxia. The metabolic pathway analysis identified taurine metabolism and TCA as important pathways that might have contributed to hypobaric hypoxia-induced pathophysiology. This study demonstrates the use of metabolomics as a promising tool for discovery and understanding of novel biochemical responses to hypobaric hypoxia exposure, providing new insight in the field of high altitude medicine and the attendant health problems that occur in response to high altitude. The findings reported here also have potential relevance for sports medicine and aviation sciences.

  6. "Omics" of High Altitude Biology: A Urinary Metabolomics Biomarker Study of Rats Under Hypobaric Hypoxia.

    PubMed

    Koundal, Sunil; Gandhi, Sonia; Kaur, Tanzeer; Mazumder, Avik; Khushu, Subash

    2015-12-01

    High altitude medicine is an emerging subspecialty that has crosscutting relevance for 21(st) century science and society: from sports medicine and aerospace industry to urban and rural communities living in high altitude. Recreational travel to high altitude has also become increasingly popular. Rarely has the biology of high altitude biology been studied using systems sciences and omics high-throughput technologies. In the present study, 1H-NMR-based metabolomics, along with multivariate analyses, were employed in a preclinical rat model to characterize the urinary metabolome under hypobaric hypoxia stress. Rats were exposed to simulated altitude of 6700 m above the sea level. The urine samples were collected from pre- and post-exposure (1, 3, 7, and 14 days) of hypobaric hypoxia. Metabolomics urinalysis showed alterations in TCA cycle metabolites (citrate, α-ketoglutarate), cell membrane metabolism (choline), gut micro-flora metabolism (hippurate, phenylacetylglycine), and others (N-acetyl glutamate, creatine, taurine) in response to hypobaric hypoxia. Taurine, a potential biomarker of hepatic function, was elevated after 3 days of hypobaric hypoxia, which indicates altered liver functioning. Liver histopathology confirmed the damage to tissue architecture due to hypobaric hypoxia. The metabolic pathway analysis identified taurine metabolism and TCA as important pathways that might have contributed to hypobaric hypoxia-induced pathophysiology. This study demonstrates the use of metabolomics as a promising tool for discovery and understanding of novel biochemical responses to hypobaric hypoxia exposure, providing new insight in the field of high altitude medicine and the attendant health problems that occur in response to high altitude. The findings reported here also have potential relevance for sports medicine and aviation sciences. PMID:26669710

  7. Whole-genome sequencing of six dog breeds from continuous altitudes reveals adaptation to high-altitude hypoxia

    PubMed Central

    Gou, Xiao; Wang, Zhen; Li, Ning; Qiu, Feng; Xu, Ze; Yan, Dawei; Yang, Shuli; Jia, Jia; Kong, Xiaoyan; Wei, Zehui; Lu, Shaoxiong; Lian, Linsheng; Wu, Changxin; Wang, Xueyan; Li, Guozhi; Ma, Teng; Jiang, Qiang; Zhao, Xue; Yang, Jiaqiang; Liu, Baohong; Wei, Dongkai; Li, Hong; Yang, Jianfa; Yan, Yulin; Zhao, Guiying; Dong, Xinxing; Li, Mingli; Deng, Weidong; Leng, Jing; Wei, Chaochun; Wang, Chuan; Mao, Huaming; Zhang, Hao; Ding, Guohui; Li, Yixue

    2014-01-01

    The hypoxic environment imposes severe selective pressure on species living at high altitude. To understand the genetic bases of adaptation to high altitude in dogs, we performed whole-genome sequencing of 60 dogs including five breeds living at continuous altitudes along the Tibetan Plateau from 800 to 5100 m as well as one European breed. More than 150× sequencing coverage for each breed provides us with a comprehensive assessment of the genetic polymorphisms of the dogs, including Tibetan Mastiffs. Comparison of the breeds from different altitudes reveals strong signals of population differentiation at the locus of hypoxia-related genes including endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1) and beta hemoglobin cluster. Notably, four novel nonsynonymous mutations specific to high-altitude dogs are identified at EPAS1, one of which occurred at a quite conserved site in the PAS domain. The association testing between EPAS1 genotypes and blood-related phenotypes on additional high-altitude dogs reveals that the homozygous mutation is associated with decreased blood flow resistance, which may help to improve hemorheologic fitness. Interestingly, EPAS1 was also identified as a selective target in Tibetan highlanders, though no amino acid changes were found. Thus, our results not only indicate parallel evolution of humans and dogs in adaptation to high-altitude hypoxia, but also provide a new opportunity to study the role of EPAS1 in the adaptive processes. PMID:24721644

  8. [Dynamic structure of the cardiac rhythm in the process of adapting to high-altitude hypoxia].

    PubMed

    Shukurov, F A; Nidekker, I G

    1981-01-01

    On the basis of dynamic series of RR intervals of electrocardiograms of healthy male test subjects exposed for a different period of time to high altitude hypoxia, autoregression clouds were built. The patterns of distribution thus obtained were compared with physical work capacity of the test subjects. It is suggested that when selecting people to work actively at high altitudes autoregression clouds can be used as quantitative estimates of their health state and as predictions of potential adaptation failures.

  9. Shared Genetic Signals of Hypoxia Adaptation in Drosophila and in High-Altitude Human Populations

    PubMed Central

    Jha, Aashish R.; Zhou, Dan; Brown, Christopher D.; Kreitman, Martin; Haddad, Gabriel G.; White, Kevin P.

    2016-01-01

    The ability to withstand low oxygen (hypoxia tolerance) is a polygenic and mechanistically conserved trait that has important implications for both human health and evolution. However, little is known about the diversity of genetic mechanisms involved in hypoxia adaptation in evolving populations. We used experimental evolution and whole-genome sequencing in Drosophila melanogaster to investigate the role of natural variation in adaptation to hypoxia. Using a generalized linear mixed model we identified significant allele frequency differences between three independently evolved hypoxia-tolerant populations and normoxic control populations for approximately 3,800 single nucleotide polymorphisms. Around 50% of these variants are clustered in 66 distinct genomic regions. These regions contain genes that are differentially expressed between hypoxia-tolerant and normoxic populations and several of the differentially expressed genes are associated with metabolic processes. Additional genes associated with respiratory and open tracheal system development also show evidence of directional selection. RNAi-mediated knockdown of several candidate genes’ expression significantly enhanced survival in severe hypoxia. Using genomewide single nucleotide polymorphism data from four high-altitude human populations—Sherpas, Tibetans, Ethiopians, and Andeans, we found that several human orthologs of the genes under selection in flies are also likely under positive selection in all four high-altitude human populations. Thus, our results indicate that selection for hypoxia tolerance can act on standing genetic variation in similar genes and pathways present in organisms diverged by hundreds of millions of years. PMID:26576852

  10. Does hypoxia impair ovarian function in Bolivian women indigenous to high altitude?

    PubMed

    Vitzthum, V J; Ellison, P T; Sukalich, S; Caceres, E; Spielvogel, H

    2000-01-01

    Fertility appears to be reduced in at least some high altitude populations relative to their counterparts at lower elevations. Inferring from the difficulties with reproduction of newcomers to high altitude and from animal experiments, it has been hypothesized that this apparent reduction is the result of hypoxia acting to reduce fecundity and/or increase fetal loss. In humans, however, several behavioral as well as biological factors may affect fertility levels. These many factors have been organized by demographers into a framework of seven proximate determinants that includes fecundability (the monthly probability of conception) of which successful ovulation is one component. To test whether ovarian function is impaired in women indigenous to high altitude, we measured salivary progesterone (P) in a sample (n = 20) of Quechua women (aged 19-42 years) residing at 3,100 m. It was found that mean luteal P = 179 pmol/L and mean midluteal P = 243 pmol/L, levels that fall about midway in the range of known values for several populations and are higher than some lower altitude populations. These findings suggest that hypoxia does not appear to significantly impair ovarian function in those with lifelong residence at high altitude. There are, however, several factors common to many high altitude populations that may act to reduce fecundability and fertility including intercourse patterns (affected by marriage and migration practices), prolonged lactation, dietary insufficiency, and hard labor.

  11. Cerebrovascular responses to hypoxia and hypocapnia in high-altitude dwellers

    PubMed Central

    Norcliffe, LJ; Rivera-Ch, M; Claydon, VE; Moore, JP; Leon-Velarde, F; Appenzeller, O; Hainsworth, R

    2005-01-01

    CerebRal blood flow is known to increase in response to hypoxia and to decrease with hypocapnia. It is not known, however, whether these responses are altered in high-altitude dwellers who are not only chronically hypoxic and hypocapnic, but also polycythaemic. Here we examined cerebral blood flow responses to hypoxia and hypocapnia, separately and together, in Andean high-altitude dwellers, including some with chronic mountain sickness (CMS), which is characterized by excessive polycythaemia. Studies were carried out at high altitude (Cerro de Pasco (CP), Peru; barometric pressure (PB) 450 mmHg) and repeated, following relief of the hypoxia, on the day following arrival at sea level (Lima, Peru; PB 755 mmHg). We compared these results with those from eight sea-level residents studied at sea level. In nine high-altitude normal subjects (HA) and nine CMS patients, we recorded middle cerebral artery mean blood flow velocity (MCAVm) using transcranial Doppler ultrasonography, and expressed responses as changes from baseline. MCAVm responses to hypoxia were determined by changing end-tidal partial pressure of oxygen (PET,O2) from 100 to 50 mmHg, with end-tidal partial pressure of carbon dioxide clamped. MCAVm responses to hypocapnia were studied by voluntary hyperventilation with (PET,O2) clamped at 100 and 50 mmHg. There were no significant differences between the cerebrovascular responses of the two groups to any of the interventions at either location. In both groups, the MCAVm responses to hypoxia were significantly greater at Lima than at CP (HA, 12.1 ± 1.3 and 6.1 ± 1.0%; CMS, 12.5 ± 0.8 and 5.6 ± 1.2%; P < 0.01 both groups). The responses at Lima were similar to those in the sea-level subjects (13.6 ± 2.3%). The responses to normoxic hypocapnia in the altitude subjects were also similar at both locations and greater than those in sea-level residents. During hypoxia, both high-altitude groups showed responses to hypocapnia that were significantly smaller at

  12. Cerebrovascular responses to hypoxia and hypocapnia in high-altitude dwellers.

    PubMed

    Norcliffe, L J; Rivera-Ch, M; Claydon, V E; Moore, J P; Leon-Velarde, F; Appenzeller, O; Hainsworth, R

    2005-07-01

    Cerebral blood flow is known to increase in response to hypoxia and to decrease with hypocapnia. It is not known, however, whether these responses are altered in high-altitude dwellers who are not only chronically hypoxic and hypocapnic, but also polycythaemic. Here we examined cerebral blood flow responses to hypoxia and hypocapnia, separately and together, in Andean high-altitude dwellers, including some with chronic mountain sickness (CMS), which is characterized by excessive polycythaemia. Studies were carried out at high altitude (Cerro de Pasco (CP), Peru; barometric pressure (P(B)) 450 mmHg) and repeated, following relief of the hypoxia, on the day following arrival at sea level (Lima, Peru; P(B) 755 mmHg). We compared these results with those from eight sea-level residents studied at sea level. In nine high-altitude normal subjects (HA) and nine CMS patients, we recorded middle cerebral artery mean blood flow velocity (MCAVm) using transcranial Doppler ultrasonography, and expressed responses as changes from baseline. MCAVm responses to hypoxia were determined by changing end-tidal partial pressure of oxygen (P(ET,O2)) from 100 to 50 mmHg, with end-tidal partial pressure of carbon dioxide clamped. MCAVm responses to hypocapnia were studied by voluntary hyperventilation with (P(ET,O2)) clamped at 100 and 50 mmHg. There were no significant differences between the cerebrovascular responses of the two groups to any of the interventions at either location. In both groups, the MCAVm responses to hypoxia were significantly greater at Lima than at CP (HA, 12.1 +/- 1.3 and 6.1 +/- 1.0%; CMS, 12.5 +/- 0.8 and 5.6 +/- 1.2%; P < 0.01 both groups). The responses at Lima were similar to those in the sea-level subjects (13.6 +/- 2.3%). The responses to normoxic hypocapnia in the altitude subjects were also similar at both locations and greater than those in sea-level residents. During hypoxia, both high-altitude groups showed responses to hypocapnia that were

  13. The body weight loss during acute exposure to high-altitude hypoxia in sea level residents.

    PubMed

    Ge, Ri-Li; Wood, Helen; Yang, Hui-Huang; Liu, Yi-Ning; Wang, Xiu-Juan; Babb, Tony

    2010-12-25

    altitude group (2.97±1.38), and was significantly correlated with baseline body weight. These results indicate that (1) the person with higher body weight during stay at high altitude loses more weight, and this is more pronounced in sea level natives when compared with that in moderate altitude natives; (2) heavier individuals are more likely to develop AMS than leaner individuals during exposure to high-altitude hypoxia.

  14. Placental villus morphology in relation to maternal hypoxia at high altitude.

    PubMed

    Espinoza, J; Sebire, N J; McAuliffe, F; Krampl, E; Nicolaides, K H

    2001-07-01

    Pregnancy at high altitude is associated with maternal hypoxaemic hypoxia with resultant intervillus blood hypoxia. Maternal haemoglobin concentration and blood gases were measured in pregnant women in two cities in Peru; Lima at sea level (n=18) and Cerro de Pasco at 4300 metres above sea level (n=12). Following delivery, placental sections from both groups were examined histomorphometrically using an image analysis system. Villus diameter, villus cross-sectional area, capillary diameter, capillary cross-sectional area and the percentage of villus cross-sectional area occupied by villus capillaries were calculated and parameters were compared between the two altitude groups. Maternal haemoglobin concentration and maternal blood pH were significantly higher, and maternal pO(2), pCO(2)and O(2)saturation were significantly lower in the high altitude group compared to those at sea level. The villus vessel area as a percentage of villus cross-sectional area and capillary diameter were significantly greater in the cases from the high altitude group and villus vessel area as a percentage of the villus cross-sectional area was significantly related to maternal pO(2)(r=-0.7, P=0.01), and maternal pCO(2)(r=0.7, P=0.02), but multiple regression analysis demonstrated that only pO(2)remained significantly independently associated with these villus histological findings (P=0.03). Placental terminal villi from term pregnancies at high altitude show different morphological features from pregnancies at sea level, and these changes are primarily related to maternal pO(2). The predominant morphological alteration is an increase in villus capillary diameter and therefore of the proportion of villus cross-sectional area occupied by capillary lumens.

  15. Exhaled nitric oxide decreases upon acute exposure to high-altitude hypoxia.

    PubMed

    Brown, Daniel E; Beall, Cynthia M; Strohl, Kingman P; Mills, Phoebe S

    2006-01-01

    Nitric oxide (NO) is a vasodilator that plays a role in blood flow and oxygen delivery. Acute hypoxia down regulates NO synthesis, a response that may exacerbate hypoxic stress by decreasing blood flow. This study was designed to test the hypotheses that pulmonary NO decreases upon acute exposure to high-altitude hypoxia and that relatively low levels of NO at altitude are associated with greater stress as reflected in more symptoms of acute mountain sickness (AMS). A sample of 47 healthy, adult, nonsmoking, sea-level residents provided measurements at sea level, at 2,800 m, and at 0-, 2-, and 3-h exposure times at 4,200 m altitude on Mauna Kea, Hawaii. Measurements were made of exhaled NO, oxygen saturation of hemoglobin, heart rate, and reported symptoms of AMS. The partial pressure of NO concentration in exhaled breath decreased significantly from a sea level mean of 4.2 nmHg to 3.8 nmHg at 2,800 m and 3.4 nmHg at 4,200 m. NO concentration in exhaled breath did not change significantly over a 3-h exposure at 4,200 m and recovered to pre-exposure baseline upon return to sea level. There was no significant association between the level of NO exhaled and the number of self-reported symptoms of AMS during this brief exposure. PMID:16493632

  16. Reversibility of electrophysiological changes induced by chronic high-altitude hypoxia in adult rat heart.

    PubMed

    Chouabe, C; Amsellem, J; Espinosa, L; Ribaux, P; Blaineau, S; Mégas, P; Bonvallet, R

    2002-04-01

    Recent studies indicate that regression of left ventricular hypertrophy normalizes membrane ionic current abnormalities. This work was designed to determine whether regression of right ventricular hypertrophy induced by permanent high-altitude exposure (4,500 m, 20 days) in adult rats also normalizes changes of ventricular myocyte electrophysiology. According to the current data, prolonged action potential, decreased transient outward current density, and increased inward sodium/calcium exchange current density normalized 20 days after the end of altitude exposure, whereas right ventricular hypertrophy evidenced by both the right ventricular weight-to-heart weight ratio and the right ventricular free wall thickness measurement normalized 40 days after the end of altitude exposure. This morphological normalization occurred at both the level of muscular tissue, as shown by the decrease toward control values of some myocyte parameters (perimeter, capacitance, and width), and the level of the interstitial collagenous connective tissue. In the chronic high-altitude hypoxia model, the regression of right ventricular hypertrophy would not be a prerequisite for normalization of ventricular electrophysiological abnormalities. PMID:11893582

  17. A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude

    PubMed Central

    Boos, Christopher John; O’Hara, John Paul; Mellor, Adrian; Hodkinson, Peter David; Tsakirides, Costas; Reeve, Nicola; Gallagher, Liam; Green, Nicholas Donald Charles; Woods, David Richard

    2016-01-01

    Background There has been considerable debate as to whether different modalities of simulated hypoxia induce similar cardiac responses. Materials and Methods This was a prospective observational study of 14 healthy subjects aged 22–35 years. Echocardiography was performed at rest and at 15 and 120 minutes following two hours exercise under normobaric normoxia (NN) and under similar PiO2 following genuine high altitude (GHA) at 3,375m, normobaric hypoxia (NH) and hypobaric hypoxia (HH) to simulate the equivalent hypoxic stimulus to GHA. Results All 14 subjects completed the experiment at GHA, 11 at NN, 12 under NH, and 6 under HH. The four groups were similar in age, sex and baseline demographics. At baseline rest right ventricular (RV) systolic pressure (RVSP, p = 0.0002), pulmonary vascular resistance (p = 0.0002) and acute mountain sickness (AMS) scores were higher and the SpO2 lower (p<0.0001) among all three hypoxic groups (GHA, NH and HH) compared with NN. At both 15 minutes and 120 minutes post exercise, AMS scores, Cardiac output, septal S’, lateral S’, tricuspid S’ and A’ velocities and RVSP were higher and SpO2 lower with all forms of hypoxia compared with NN. On post-test analysis, among the three hypoxia groups, SpO2 was lower at baseline and 15 minutes post exercise with GHA (89.3±3.4% and 89.3±2.2%) and HH (89.0±3.1 and (89.8±5.0) compared with NH (92.9±1.7 and 93.6±2.5%). The RV Myocardial Performance (Tei) Index and RVSP were significantly higher with HH than NH at 15 and 120 minutes post exercise respectively and tricuspid A’ was higher with GHA compared with NH at 15 minutes post exercise. Conclusions GHA, NH and HH produce similar cardiac adaptations over short duration rest despite lower SpO2 levels with GHA and HH compared with NH. Notable differences emerge following exercise in SpO2, RVSP and RV cardiac function. PMID:27100313

  18. Sphingosine-1-phosphate promotes erythrocyte glycolysis and oxygen release for adaptation to high-altitude hypoxia

    PubMed Central

    Sun, Kaiqi; Zhang, Yujin; D'Alessandro, Angelo; Nemkov, Travis; Song, Anren; Wu, Hongyu; Liu, Hong; Adebiyi, Morayo; Huang, Aji; Wen, Yuan E.; Bogdanov, Mikhail V.; Vila, Alejandro; O'Brien, John; Kellems, Rodney E.; Dowhan, William; Subudhi, Andrew W.; Jameson-Van Houten, Sonja; Julian, Colleen G.; Lovering, Andrew T.; Safo, Martin; Hansen, Kirk C.; Roach, Robert C.; Xia, Yang

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive signalling lipid highly enriched in mature erythrocytes, with unknown functions pertaining to erythrocyte physiology. Here by employing nonbiased high-throughput metabolomic profiling, we show that erythrocyte S1P levels rapidly increase in 21 healthy lowland volunteers at 5,260 m altitude on day 1 and continue increasing to 16 days with concurrently elevated erythrocyte sphingonisne kinase 1 (Sphk1) activity and haemoglobin (Hb) oxygen (O2) release capacity. Mouse genetic studies show that elevated erythrocyte Sphk1-induced S1P protects against tissue hypoxia by inducing O2 release. Mechanistically, we show that intracellular S1P promotes deoxygenated Hb anchoring to the membrane, enhances the release of membrane-bound glycolytic enzymes to the cytosol, induces glycolysis and thus the production of 2,3-bisphosphoglycerate (2,3-BPG), an erythrocyte-specific glycolytic intermediate, which facilitates O2 release. Altogether, we reveal S1P as an intracellular hypoxia-responsive biolipid promoting erythrocyte glycolysis, O2 delivery and thus new therapeutic opportunities to counteract tissue hypoxia. PMID:27417539

  19. Higher blood flow and circulating NO products offset high-altitude hypoxia among Tibetans.

    PubMed

    Erzurum, S C; Ghosh, S; Janocha, A J; Xu, W; Bauer, S; Bryan, N S; Tejero, J; Hemann, C; Hille, R; Stuehr, D J; Feelisch, M; Beall, C M

    2007-11-01

    The low barometric pressure at high altitude causes lower arterial oxygen content among Tibetan highlanders, who maintain normal levels of oxygen use as indicated by basal and maximal oxygen consumption levels that are consistent with sea level predictions. This study tested the hypothesis that Tibetans resident at 4,200 m offset physiological hypoxia and achieve normal oxygen delivery by means of higher blood flow enabled by higher levels of bioactive forms of NO, the main endothelial factor regulating blood flow and vascular resistance. The natural experimental study design compared Tibetans at 4,200 m and U.S. residents at 206 m. Eighty-eight Tibetan and 50 U.S. resident volunteers (18-56 years of age, healthy, nonsmoking, nonhypertensive, not pregnant, with normal pulmonary function) participated. Forearm blood flow, an indicator of systemic blood flow, was measured noninvasively by using plethysmography at rest, after breathing supplemental oxygen, and after exercise. The Tibetans had more than double the forearm blood flow of low-altitude residents, resulting in greater than sea level oxygen delivery to tissues. In comparison to sea level controls, Tibetans had >10-fold-higher circulating concentrations of bioactive NO products, including plasma and red blood cell nitrate and nitroso proteins and plasma nitrite, but lower concentrations of iron nitrosyl complexes (HbFeIINO) in red blood cells. This suggests that NO production is increased and that metabolic pathways controlling formation of NO products are regulated differently among Tibetans. These findings shift attention from the traditional focus on pulmonary and hematological systems to vascular factors contributing to adaptation to high-altitude hypoxia. PMID:17971439

  20. Effect of Vitamin E Supplementation on Intestinal Barrier Function in Rats Exposed to High Altitude Hypoxia Environment

    PubMed Central

    Sun, Rui; Qiao, Xiangjin; Xu, Cuicui; Shang, Xiaoya; Niu, Weining; Chao, Yu

    2014-01-01

    The study was conducted to investigate the role of vitamin E in the high altitude hypoxia-induced damage to the intestinal barrier in rats. Sprague-Dawley rats were divided into control (Control), high altitude hypoxia (HH), and high altitude hypoxia+vitamin E (250 mg/kg BW*d) (HV) groups. After the third day, the HH and HV groups were placed in a hypobaric chamber at a stimulated elevation of 7000 m for 5 days. The rats in the HV group were given vitamin E by gavage daily for 8 days. The other rats were given equal volume saline. The results showed that high altitude hypoxia caused the enlargement of heart, liver, lung and kidney, and intestinal villi damage. Supplementation with vitamin E significantly alleviated hypoxia-caused damage to the main organs including intestine, increased the serum superoxide dismutase (SOD) (p< 0.05), diamino oxidase (DAO) (p< 0.01) levels, and decreased the serum levels of interleukin-2 (IL-2) (p< 0.01), interleukin-4 (IL-4) (p<0.001), interferon-gamma (IFN-γ) (p<0.01) and malondialdehyde (MDA) (p<0.001), and decreased the serum erythropoietin (EPO) activity (p<0.05). Administration of vitamin E significantly increased the S-IgA (p<0.001) in ileum and significantly improved the expression levels of occludin and IκBα, and decreased the expression levels of hypoxia-inducible factor 1 alpha and 2 alpha (HIF-1α and HIF-2α), Toll-like receptors (TLR4), P-IκBα and nuclear factor-κB p65(NF-κB P65) in ileum compared to the HH group. This study suggested that vitamin E protectis from intestinal injury caused by high altitude hypoxia environment. These effects may be related to the HIF and TLR4/NF-κB signaling pathway. PMID:25177163

  1. Altitude matters: differences in cardiovascular and respiratory responses to hypoxia in bar-headed geese reared at high and low altitudes.

    PubMed

    Lague, Sabine L; Chua, Beverly; Farrell, Anthony P; Wang, Yuxiang; Milsom, William K

    2016-07-01

    Bar-headed geese (Anser indicus) fly at high altitudes during their migration across the Himalayas and Tibetan plateau. However, we know relatively little about whether rearing at high altitude (i.e. phenotypic plasticity) facilitates this impressive feat because most of what is known about their physiology comes from studies performed at sea level. To provide this information, a comprehensive analysis of metabolic, cardiovascular and ventilatory responses to progressive decreases in the equivalent fractional composition of inspired oxygen (FiO2 : 0.21, 0.12, 0.09, 0.07 and 0.05) was made on bar-headed geese reared at either high altitude (3200 m) or low altitude (0 m) and on barnacle geese (Branta leucopsis), a low-altitude migrating species, reared at low altitude (0 m). Bar-headed geese reared at high altitude exhibited lower metabolic rates and a modestly increased hypoxic ventilatory response compared with low-altitude-reared bar-headed geese. Although the in vivo oxygen equilibrium curves and blood-oxygen carrying capacity did not differ between the two bar-headed goose study groups, the blood-oxygen carrying capacity was higher than that of barnacle geese. Resting cardiac output also did not differ between groups and increased at least twofold during progressive hypoxia, initially as a result of increases in stroke volume. However, cardiac output increased at a higher FiO2  threshold in bar-headed geese raised at high altitude. Thus, bar-headed geese reared at high altitude exhibited a reduced oxygen demand at rest and a modest but significant increase in oxygen uptake and delivery during progressive hypoxia compared with bar-headed geese reared at low altitude. PMID:27385754

  2. Glucose intolerance associated with hypoxia in people living at high altitudes in the Tibetan highland

    PubMed Central

    Okumiya, Kiyohito; Sakamoto, Ryota; Ishimoto, Yasuko; Kimura, Yumi; Fukutomi, Eriko; Ishikawa, Motonao; Suwa, Kuniaki; Imai, Hissei; Chen, Wenling; Kato, Emiko; Nakatsuka, Masahiro; Kasahara, Yoriko; Fujisawa, Michiko; Wada, Taizo; Wang, Hongxin; Dai, Qingxiang; Xu, Huining; Qiao, Haisheng; Ge, Ri-Li; Norboo, Tsering; Tsering, Norboo; Kosaka, Yasuyuki; Nose, Mitsuhiro; Yamaguchi, Takayoshi; Tsukihara, Toshihiro; Ando, Kazuo; Inamura, Tetsuya; Takeda, Shinya; Ishine, Masayuki; Otsuka, Kuniaki; Matsubayashi, Kozo

    2016-01-01

    Objectives To clarify the association between glucose intolerance and high altitudes (2900–4800 m) in a hypoxic environment in Tibetan highlanders and to verify the hypothesis that high altitude dwelling increases vulnerability to diabetes mellitus (DM) accelerated by lifestyle change or ageing. Design Cross-sectional epidemiological study on Tibetan highlanders. Participants We enrolled 1258 participants aged 40–87 years. The rural population comprised farmers in Domkhar (altitude 2900–3800 m) and nomads in Haiyan (3000–3100 m), Ryuho (4400 m) and Changthang (4300–4800 m). Urban area participants were from Leh (3300 m) and Jiegu (3700 m). Main outcome measure Participants were classified into six glucose tolerance-based groups: DM, intermediate hyperglycaemia (IHG), normoglycaemia (NG), fasting DM, fasting IHG and fasting NG. Prevalence of glucose intolerance was compared in farmers, nomads and urban dwellers. Effects of dwelling at high altitude or hypoxia on glucose intolerance were analysed with the confounding factors of age, sex, obesity, lipids, haemoglobin, hypertension and lifestyle, using multiple logistic regression. Results The prevalence of DM (fasting DM)/IHG (fasting IHG) was 8.9% (6.5%)/25.1% (12.7%), respectively, in all participants. This prevalence was higher in urban dwellers (9.5% (7.1%)/28.5% (11.7%)) and in farmers (8.5% (6.1%)/28.5% (18.3%)) compared with nomads (8.2% (5.7%)/15.7% (9.7%)) (p=0.0140/0.0001). Dwelling at high altitude was significantly associated with fasting IHG+fasting DM/fasting DM (ORs for >4500 and 3500–4499 m were 3.59/4.36 and 2.07/1.76 vs <3500 m, respectively). After adjusting for lifestyle change, hypoxaemia and polycythaemia were closely associated with glucose intolerance. Conclusions Socioeconomic factors, hypoxaemia and the effects of altitudes >3500 m play a major role in the high prevalence of glucose intolerance in highlanders. Tibetan highlanders may be vulnerable to glucose

  3. Perinatal hypoxia increases susceptibility to high-altitude polycythemia and attendant pulmonary vascular dysfunction.

    PubMed

    Julian, Colleen Glyde; Gonzales, Marcelino; Rodriguez, Armando; Bellido, Diva; Salmon, Carlos Salinas; Ladenburger, Anne; Reardon, Lindsay; Vargas, Enrique; Moore, Lorna G

    2015-08-15

    Perinatal exposures exert a profound influence on physiological function, including developmental processes vital for efficient pulmonary gas transfer throughout the lifespan. We extend the concept of developmental programming to chronic mountain sickness (CMS), a debilitating syndrome marked by polycythemia, ventilatory impairment, and pulmonary hypertension that affects ∼10% of male high-altitude residents. We hypothesized that adverse perinatal oxygenation caused abnormalities of ventilatory and/or pulmonary vascular function that increased susceptibility to CMS in adulthood. Subjects were 67 male high-altitude (3,600-4,100 m) residents aged 18-25 yr with excessive erythrocytosis (EE, Hb concentration ≥18.3 g/dl), a preclinical form of CMS, and 66 controls identified from a community-based survey (n = 981). EE subjects not only had higher Hb concentrations and erythrocyte counts, but also lower alveolar ventilation, impaired pulmonary diffusion capacity, higher systolic pulmonary artery pressure, lower pulmonary artery acceleration time, and more frequent right ventricular hypertrophy, than controls. Compared with controls, EE subjects were more often born to mothers experiencing hypertensive complications of pregnancy and hypoxia during the perinatal period, with each increasing the risk of developing EE (odds ratio = 5.25, P = 0.05 and odds ratio = 6.44, P = 0.04, respectively) after other factors known to influence EE status were taken into account. Adverse perinatal oxygenation is associated with increased susceptibility to EE accompanied by modest abnormalities of the pulmonary circulation that are independent of increased blood viscosity. The association between perinatal hypoxia and EE may be due to disrupted alveolarization and microvascular development, leading to impaired gas exchange and/or pulmonary hypertension.

  4. Perinatal hypoxia increases susceptibility to high-altitude polycythemia and attendant pulmonary vascular dysfunction

    PubMed Central

    Gonzales, Marcelino; Rodriguez, Armando; Bellido, Diva; Salmon, Carlos Salinas; Ladenburger, Anne; Reardon, Lindsay; Vargas, Enrique; Moore, Lorna G.

    2015-01-01

    Perinatal exposures exert a profound influence on physiological function, including developmental processes vital for efficient pulmonary gas transfer throughout the lifespan. We extend the concept of developmental programming to chronic mountain sickness (CMS), a debilitating syndrome marked by polycythemia, ventilatory impairment, and pulmonary hypertension that affects ∼10% of male high-altitude residents. We hypothesized that adverse perinatal oxygenation caused abnormalities of ventilatory and/or pulmonary vascular function that increased susceptibility to CMS in adulthood. Subjects were 67 male high-altitude (3,600–4,100 m) residents aged 18–25 yr with excessive erythrocytosis (EE, Hb concentration ≥18.3 g/dl), a preclinical form of CMS, and 66 controls identified from a community-based survey (n = 981). EE subjects not only had higher Hb concentrations and erythrocyte counts, but also lower alveolar ventilation, impaired pulmonary diffusion capacity, higher systolic pulmonary artery pressure, lower pulmonary artery acceleration time, and more frequent right ventricular hypertrophy, than controls. Compared with controls, EE subjects were more often born to mothers experiencing hypertensive complications of pregnancy and hypoxia during the perinatal period, with each increasing the risk of developing EE (odds ratio = 5.25, P = 0.05 and odds ratio = 6.44, P = 0.04, respectively) after other factors known to influence EE status were taken into account. Adverse perinatal oxygenation is associated with increased susceptibility to EE accompanied by modest abnormalities of the pulmonary circulation that are independent of increased blood viscosity. The association between perinatal hypoxia and EE may be due to disrupted alveolarization and microvascular development, leading to impaired gas exchange and/or pulmonary hypertension. PMID:26092986

  5. High-altitude ancestry and hypoxia acclimation have distinct effects on exercise capacity and muscle phenotype in deer mice.

    PubMed

    Lui, Mikaela A; Mahalingam, Sajeni; Patel, Paras; Connaty, Alex D; Ivy, Catherine M; Cheviron, Zachary A; Storz, Jay F; McClelland, Grant B; Scott, Graham R

    2015-05-01

    The hypoxic and cold environment at high altitudes requires that small mammals sustain high rates of O2 transport for exercise and thermogenesis while facing a diminished O2 availability. We used laboratory-born and -raised deer mice (Peromyscus maniculatus) from highland and lowland populations to determine the interactive effects of ancestry and hypoxia acclimation on exercise performance. Maximal O₂consumption (V̇o(2max)) during exercise in hypoxia increased after hypoxia acclimation (equivalent to the hypoxia at ∼4,300 m elevation for 6-8 wk) and was consistently greater in highlanders than in lowlanders. V̇o(2max) during exercise in normoxia was not affected by ancestry or acclimation. Highlanders also had consistently greater capillarity, oxidative fiber density, and maximal activities of oxidative enzymes (cytochrome c oxidase and citrate synthase) in the gastrocnemius muscle, lower lactate dehydrogenase activity in the gastrocnemius, and greater cytochrome c oxidase activity in the diaphragm. Hypoxia acclimation did not affect any of these muscle traits. The unique gastrocnemius phenotype of highlanders was associated with higher mRNA and protein abundances of peroxisome proliferator-activated receptor γ (PPARγ). Vascular endothelial growth factor (VEGFA) transcript abundance was lower in highlanders, and hypoxia acclimation reduced the expression of numerous genes that regulate angiogenesis and energy metabolism, in contrast to the observed population differences in muscle phenotype. Lowlanders exhibited greater increases in blood hemoglobin content, hematocrit, and wet lung mass (but not dry lung mass) than highlanders after hypoxia acclimation. Genotypic adaptation to high altitude, therefore, improves exercise performance in hypoxia by mechanisms that are at least partially distinct from those underlying hypoxia acclimation. PMID:25695288

  6. High-altitude ancestry and hypoxia acclimation have distinct effects on exercise capacity and muscle phenotype in deer mice

    PubMed Central

    Lui, Mikaela A.; Mahalingam, Sajeni; Patel, Paras; Connaty, Alex D.; Ivy, Catherine M.; Cheviron, Zachary A.; Storz, Jay F.; McClelland, Grant B.

    2015-01-01

    The hypoxic and cold environment at high altitudes requires that small mammals sustain high rates of O2 transport for exercise and thermogenesis while facing a diminished O2 availability. We used laboratory-born and -raised deer mice (Peromyscus maniculatus) from highland and lowland populations to determine the interactive effects of ancestry and hypoxia acclimation on exercise performance. Maximal O2 consumption (V̇o2max) during exercise in hypoxia increased after hypoxia acclimation (equivalent to the hypoxia at ∼4,300 m elevation for 6–8 wk) and was consistently greater in highlanders than in lowlanders. V̇o2max during exercise in normoxia was not affected by ancestry or acclimation. Highlanders also had consistently greater capillarity, oxidative fiber density, and maximal activities of oxidative enzymes (cytochrome c oxidase and citrate synthase) in the gastrocnemius muscle, lower lactate dehydrogenase activity in the gastrocnemius, and greater cytochrome c oxidase activity in the diaphragm. Hypoxia acclimation did not affect any of these muscle traits. The unique gastrocnemius phenotype of highlanders was associated with higher mRNA and protein abundances of peroxisome proliferator-activated receptor γ (PPARγ). Vascular endothelial growth factor (VEGFA) transcript abundance was lower in highlanders, and hypoxia acclimation reduced the expression of numerous genes that regulate angiogenesis and energy metabolism, in contrast to the observed population differences in muscle phenotype. Lowlanders exhibited greater increases in blood hemoglobin content, hematocrit, and wet lung mass (but not dry lung mass) than highlanders after hypoxia acclimation. Genotypic adaptation to high altitude, therefore, improves exercise performance in hypoxia by mechanisms that are at least partially distinct from those underlying hypoxia acclimation. PMID:25695288

  7. Tibetan and Andean patterns of adaptation to high-altitude hypoxia.

    PubMed

    Beall, C M

    2000-02-01

    Understanding the workings of the evolutionary process in contemporary humans requires linking the evolutionary history of traits with their current genetics and biology. Unusual environments provide natural experimental settings to investigate evolution and adaptation. The example of high-altitude hypoxia illustrates some of the progress and many of the remaining challenges for studies of evolution in contemporary populations. Current studies exemplify the frequently encountered problem of determining whether large, consistent population differences in mean values of a trait reflect genetic differences. In this review I describe 4 quantitative traits that provide evidence that indigenous populations of the Tibetan and Andean plateaus differ in their phenotypic adaptive responses to high-altitude hypoxia. These 4 traits are resting ventilation, hypoxic ventilatory response, oxygen saturation, and hemoglobin concentration. The Tibetan means of the first 2 traits were more than 0.5 standard deviation higher than the Aymara means, whereas the Tibetan means were more than 1 standard deviation lower than the Aymara means for the last 2 traits. Quantitative genetic analyses of within-population variance revealed significant genetic variance in all 4 traits in the Tibetan population but only in hypoxic ventilatory response and hemoglobin concentration in the Aymara population. A major gene for oxygen saturation was detected among the Tibetans. These findings are interpreted as indirect evidence of population genetic differences. It appears that the biological characteristics of sea-level humans did not constrain high-altitude colonists of the 2 plateaus to a single adaptive response. Instead, microevolutionary processes may have operated differently in the geographically separated Tibetan and Andean populations exposed to the same environmental stress. Knowledge of the genetic bases of these traits will be necessary to evaluate these inferences. Future research will

  8. Regional differences in the cerebral blood flow velocity response to hypobaric hypoxia at high altitudes.

    PubMed

    Feddersen, Berend; Neupane, Pritam; Thanbichler, Florian; Hadolt, Irmgard; Sattelmeyer, Vera; Pfefferkorn, Thomas; Waanders, Robb; Noachtar, Soheyl; Ausserer, Harald

    2015-11-01

    Symptoms of acute mountain sickness (AMS) may appear above 2,500 m altitude, if the time allowed for acclimatization is insufficient. As the mechanisms underlying brain adaptation to the hypobaric hypoxic environment are not fully understood, a prospective study was performed investigating neurophysiological changes by means of near infrared spectroscopy, electroencephalograpy (EEG), and transcranial doppler sonography at 100, 3,440 and 5,050 m above sea level in the Khumbu Himal, Nepal. Fourteen of the 26 mountaineers reaching 5,050 m altitude developed symptoms of AMS between 3,440 and 5,050 m altitude (Lake-Louise Score ⩾3). Their EEG frontal beta activity and occipital alpha activity increased between 100 and 3,440 m altitude, i.e., before symptoms appeared. Cerebral blood flow velocity (CBFV) in the anterior and middle cerebral arteries (MCAs) increased in all mountaineers between 100 and 3,440 m altitude. During further ascent to 5,050 altitude, mountaineers with AMS developed a further increase in CBFV in the MCA, whereas in all mountaineers CBFV decreased continuously with increasing altitude in the posterior cerebral arteries. These results indicate that hypobaric hypoxia causes different regional changes in CBFV despite similar electrophysiological changes.

  9. Regional differences in the cerebral blood flow velocity response to hypobaric hypoxia at high altitudes

    PubMed Central

    Feddersen, Berend; Neupane, Pritam; Thanbichler, Florian; Hadolt, Irmgard; Sattelmeyer, Vera; Pfefferkorn, Thomas; Waanders, Robb; Noachtar, Soheyl; Ausserer, Harald

    2015-01-01

    Symptoms of acute mountain sickness (AMS) may appear above 2,500 m altitude, if the time allowed for acclimatization is insufficient. As the mechanisms underlying brain adaptation to the hypobaric hypoxic environment are not fully understood, a prospective study was performed investigating neurophysiological changes by means of near infrared spectroscopy, electroencephalograpy (EEG), and transcranial doppler sonography at 100, 3,440 and 5,050 m above sea level in the Khumbu Himal, Nepal. Fourteen of the 26 mountaineers reaching 5,050 m altitude developed symptoms of AMS between 3,440 and 5,050 m altitude (Lake-Louise Score ⩾3). Their EEG frontal beta activity and occipital alpha activity increased between 100 and 3,440 m altitude, i.e., before symptoms appeared. Cerebral blood flow velocity (CBFV) in the anterior and middle cerebral arteries (MCAs) increased in all mountaineers between 100 and 3,440 m altitude. During further ascent to 5,050 m altitude, mountaineers with AMS developed a further increase in CBFV in the MCA, whereas in all mountaineers CBFV decreased continuously with increasing altitude in the posterior cerebral arteries. These results indicate that hypobaric hypoxia causes different regional changes in CBFV despite similar electrophysiological changes. PMID:26082017

  10. [The intensity of respiration in pea and corn seedlings under high-altitude hypoxia].

    PubMed

    Astafurova, T P; Ageev, B G; Sapozhnikova, V A; Ponomarev, Iu N; Zaĭtseva, T A; Zotnikova, A P

    1996-01-01

    Dynamics of CO2 gas-exchange and enzymatic activity of the respiratory metabolism of pea (Pisum sativum L.) and maize (Zea mays L.) seedlings during hypobaric hypoxia simulating the altitude of 5000 m above the sea level was studied. In the 48-hour chamber experiment (total barometric pressure is 54 kPa, partial O2 pressure is 11 kPa), the relative intensity of CO2 emission was found to increase and be essentially higher for pea than maize. Periodic reactions with small upward spikes and time offset were recorded in the pea plants. The initial increase of CO2 emission velocity by maize rapidly reached the level of saturation and since then remained constant. High velocity of the main catabolic ways and carboxylating activity in maize seedlings was the effect of hypoxic stress. Utilisation of respiratory substrates by pea seedlings was blocked at the Krebs cycle level, whereas glycolysis and oxidizing pentose phosphate pathways were activated. Weak activity of the carboxylate system does not provide refixation of endogenous carbon dioxide, excessive quantities of which invade the environment.

  11. [Pathophysiological changes in mitochondria of mammalian exposed to hypoxia at high altitude].

    PubMed

    Gao, Wen-xiang; Wu, Gang; Gao, Yu-qi

    2014-11-01

    As human beings ascend to high altitude, a number of reactions may occur against hypoxic injuries. These hypoxic responses are related to intake, transportation and utility of the oxygen. As a crucial subcellular organelle of oxygen utility, mitochondrion is a central link of high altitude acclimatization, adaptation and mountain sicknesses. In this review, we discussed the recent advances in researches on hypoxic mitochondrial responses at high altitude. PMID:26016358

  12. Human adaptation to the hypoxia of high altitude: the Tibetan paradigm from the pregenomic to the postgenomic era.

    PubMed

    Petousi, Nayia; Robbins, Peter A

    2014-04-01

    The Tibetan Plateau is one of the highest regions on Earth. Tibetan highlanders are adapted to life and reproduction in a hypoxic environment and possess a suite of distinctive physiological traits. Recent studies have identified genomic loci that have undergone natural selection in Tibetans. Two of these loci, EGLN1 and EPAS1, encode major components of the hypoxia-inducible factor transcriptional system, which has a central role in oxygen sensing and coordinating an organism's response to hypoxia, as evidenced by studies in humans and mice. An association between genetic variants within these genes and hemoglobin concentration in Tibetans at high altitude was demonstrated in some of the studies (8, 80, 96). Nevertheless, the functional variants within these genes and the underlying mechanisms of action are still not known. Furthermore, there are a number of other possible phenotypic traits, besides hemoglobin concentration, upon which natural selection may have acted. Integration of studies at the genomic level with functional molecular studies and studies in systems physiology has the potential to provide further understanding of human evolution in response to high-altitude hypoxia. The Tibetan paradigm provides further insight on the role of the hypoxia-inducible factor system in humans in relation to oxygen homeostasis.

  13. Human adaptation to the hypoxia of high altitude: the Tibetan paradigm from the pregenomic to the postgenomic era

    PubMed Central

    Petousi, Nayia

    2013-01-01

    The Tibetan Plateau is one of the highest regions on Earth. Tibetan highlanders are adapted to life and reproduction in a hypoxic environment and possess a suite of distinctive physiological traits. Recent studies have identified genomic loci that have undergone natural selection in Tibetans. Two of these loci, EGLN1 and EPAS1, encode major components of the hypoxia-inducible factor transcriptional system, which has a central role in oxygen sensing and coordinating an organism's response to hypoxia, as evidenced by studies in humans and mice. An association between genetic variants within these genes and hemoglobin concentration in Tibetans at high altitude was demonstrated in some of the studies (8, 80, 96). Nevertheless, the functional variants within these genes and the underlying mechanisms of action are still not known. Furthermore, there are a number of other possible phenotypic traits, besides hemoglobin concentration, upon which natural selection may have acted. Integration of studies at the genomic level with functional molecular studies and studies in systems physiology has the potential to provide further understanding of human evolution in response to high-altitude hypoxia. The Tibetan paradigm provides further insight on the role of the hypoxia-inducible factor system in humans in relation to oxygen homeostasis. PMID:24201705

  14. The antioxidative effect of a novel free radical scavenger 4'-hydroxyl-2-substituted phenylnitronyl nitroxide in acute high-altitude hypoxia mice.

    PubMed

    Fan, Peng-Cheng; Ma, Hui-Ping; Jing, Lin-lin; Li, Lin; Jia, Zheng-Ping

    2013-01-01

    Acute mountain sickness is caused by sub-acute hypoxia in healthy individuals going rapidly to altitude. Both tissue hypoxia in vitro and whole-body hypoxia in vivo have been found to promote the release of reactive oxygen species. Nitronyl nitroxide can trap free radicals such as ·NO or ·OH, and may therefore be efficient protective agents. This study assessed the ability of nitronyl nitroxide to against acute mountain sickness as a free radical scavenger in acute high-altitude hypoxia mice model. Normobaric hypoxia and hypobaric hypoxia model were used to estimate the protect effects of nitronyl nitroxide against acute mountain sickness. Low pressure oxygen compartment system was used to stimulate high-altitude hypobaric hypoxia environment. Mice in nitronyl nitroxide groups survived longer than acetazolamide group in normobaric hypoxia test. Hydrogen peroxide (H2O2) and malondialdehyde (MDA) increased in both cerebrum and myocardium in vehicle group. The results indicated more radicals were generated during high-altitude hypobaric hypoxia environment. In therapeutic groups H2O2 and MDA were significantly reduced while the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were similar to normal group. These results demonstrated that nitronyl nitroxide was an efficient tissue radical scavenger and a potential protective agent for acute mountain sickness.

  15. Chronic intermittent hypoxia at high altitude exposure for over 12 years: assessment of hematological, cardiovascular, and renal effects.

    PubMed

    Brito, Julio; Siqués, Patricia; León-Velarde, Fabiola; De La Cruz, Juan José; López, Vasthi; Herruzo, Rafael

    2007-01-01

    The aim of this cross-sectional study was to assess the health status of subjects weekly commuting between sea level and 3550-m altitude for at least 12 yr (average 22.1 +/- 5.8). We studied 50 healthy army men (aged 48.7 +/- 2.0) working 4 days in Putre at 3550-m altitude, with 3 days rest at sea level (SL) at Arica, Chile. Blood pressure, heart rate, Sa(O(2) ), and altitude symptoms (AMS score and sleep status) were measured at altitude (days 1, 2, and 4) and at SL (days 1, 2, and 3). Hematological parameters, lipid profile, renal function, and echocardiography were performed at SL on day 1. The results showed signs of acute exposure to hypoxia (tachycardia, high blood pressure, low Sa(O(2) )), AMS symptoms, and sleep disturbances on day 1, which rapidly decreased on day 2. In addition, echocardiographic findings showed pulmonary hypertension (PAPm > 25 mmHg, RV and RA enlargement) in 2 subjects (4%), a PAPm > 20 mmHg in 14%, and a right ventricle thickness >40 mm in 12%. Hematocrit (45 +/- 2.7) and hemoglobin (15 +/- 1.0) were elevated, but lower than in permanent residents. There was a remarkably high triglyceride level (238 +/- 162) and a mild decrease of glomerular filtration rate (34% under 90 mL/min and 8% under 80 mL/min of creatinine clearance). In conclusion, in these preliminary results, in chronic intermittent hypoxia exposure even over longer periods, most subjects still show symptoms of acute altitude illnesses, but a faster recovery. Findings in triglycerides, in the pulmonary circulation and in renal function, are also a matter of concern.

  16. High-altitude medicine.

    PubMed

    West, John B

    2012-12-15

    Medical problems occur at high altitude because of the low inspired Po(2), which is caused by the reduced barometric pressure. The classical physiological responses to high altitude include hyperventilation, polycythemia, hypoxic pulmonary vasoconstriction-increased intracellular oxidative enzymes, and increased capillary density in muscle. However, with the discovery of hypoxia-inducible factors (HIFs), it is apparent that there is a multitude of responses to cellular hypoxia. HIFs constitute a master switch determining the general response of the body to oxygen deprivation. The recent discovery of genetic changes in Tibetans has opened up an exciting area of research. The two major human populations that have adapted well to high altitude, the Tibetans and Andeans, have strikingly different phenotypes. Diseases of lowlanders going to high altitude include acute mountain sickness, high-altitude pulmonary edema, and high-altitude cerebral edema. Diseases affecting permanent residents or highlanders include chronic mountain sickness and high-altitude pulmonary hypertension. Important recent advances have been made on mitigation of the effects of the hypoxic environment. Oxygen enrichment of room air is very powerful. Every 1% increase in oxygen concentration reduces the equivalent altitude by about 300 m. This procedure is used in numerous facilities at high altitude and in a Chinese train to Lhasa. An alternative strategy is to increase the barometric pressure as in aircraft cabins. A hybrid approach combining both strategies shows promise but has never been used. Mines that are being developed at increasingly high altitudes pose great medical problems.

  17. High-altitude headache.

    PubMed

    Marmura, Michael J; Hernandez, Pablo Bandres

    2015-05-01

    High-altitude headache is one of many neurological symptoms associated with the ascent to high altitudes. Cellular hypoxia due to decreased barometric pressure seems to be the common final pathway for headache as altitude increases. Susceptibility to high-altitude headache depends on genetic factors, history of migraine, and acclimatization, but symptoms of acute mountain sickness are universal at very high altitudes. This review summarizes the pathophysiology of acute mountain sickness and high-altitude headache as well as the evidence for treatment and prevention with different drugs and devices which may be useful for regular and novice mountaineers. This includes an examination of other headache disorders which may mimic high-altitude headache. PMID:25795155

  18. Evaluation of hepatic metabolism and pharmacokinetics of ibuprofen in rats under chronic hypobaric hypoxia for targeted therapy at high altitude.

    PubMed

    Gola, Shefali; Gupta, Asheesh; Keshri, Gaurav K; Nath, Madhu; Velpandian, Thirumurthy

    2016-03-20

    With studies indicative of altered drug metabolism and pharmacokinetics (DMPK) under high altitude (HA)-induced hypobaric hypoxia, consideration of better therapeutic approaches has continuously been aimed in research for HA related illness management. DMPK of drugs like ibuprofen may get affected under hypoxia which establishes the requirement of different therapeutic dose regimen to ensure safe and effective therapy at HA. This study examined the effects of the chronic hypobaric hypoxia (CHH) on hepatic DMPK of ibuprofen in rats. Experimental animals were exposed to simulated altitude of 7620 m (∼25,000 ft) for CHH exposure (7 or 14 days) in decompression chamber and administered with ibuprofen (80 mg/kg, body weight, p.o.). Results demonstrated that CHH significantly altered PK variables of ibuprofen and activities of both phase-I and II hepatic metabolic enzymes as compared to the animals under normoxic conditions. Hepatic histopathological observations also revealed marked alterations. Increase in pro-inflammatory cytokines/chemokines viz. IL-1β, IL-2, IFN-γ, TNF-α exhibited close relevance with diminished CYP2C9 expression under CHH. Moreover, the down-regulated CYP2C9 level further supported the underlying mechanism for reduced metabolism of ibuprofen and as a result, increased retention of parent drug in the system. Increased mean retention time, Vd, T½ of ibuprofen, and decreased AUC, Cmax and clearance during CHH further strengthened the present findings. In conclusion, CHH exposure significantly affects hepatic DMPK of ibuprofen, which may further influence the usual therapeutic dose-regimen. Further, there is requirement of human studies to evaluate their susceptibility toward hypobaric hypoxia.

  19. Genetic adaptation to extreme hypoxia: study of high-altitude pulmonary edema in a three-generation Han Chinese family.

    PubMed

    Lorenzo, V Felipe; Yang, Yingzhong; Simonson, Tatum S; Nussenzveig, Roberto; Jorde, Lynn B; Prchal, Josef T; Ge, Ri-Li

    2009-01-01

    Organismal response to hypoxia is essential for critical regulation of erythropoiesis, other physiological functions, and survival. There is evidence of individual variation in response to hypoxia as some but not all of the affected individuals develop polycythemia, and or pulmonary and cerebral edema. A significant population difference in response to hypoxia exist as many highland Tibetan, Ethiopian, and Andean natives developed adaptive mechanisms to extreme hypoxia. A proportion of non-adapted individuals exposed to high altitude develop pulmonary edema (HAPE), pulmonary hypertension, cerebral edema, and extreme polycythemia. The isolation of causative gene(s) responsible for HAPE and other extreme hypoxia complications would provide a rational basis for specific targeted therapy of HAPE, allow its targeted prevention for at-risk populations, and clarify the pathophysiology of other hypoxic maladaptations. The only suggested genetic linkage among unrelated individuals with HAPE has been with endothelial nitric oxide synthase (eNOS) gene. Here we describe a family with multiple members affected with HAPE in three generations. Families with multiple affected members with HAPE have not been described. We first ruled out linkage of HAPE with the eNOS gene. We then performed an analysis of the whole genome using high-density SNP arrays (Affymetrix v5.0) and, assuming a single gene causation of HAPE, ruled out linkage with 34 other candidate genes. Only the HIF2A haplotype was shared by individuals who exhibit the HAPE phenotype, and work on its possible causative role in HAPE is in progress. The small size of our family does not provide sufficient power for a conclusive analysis of linkage. We hope that collaboration with other investigators with access to more HAPE patients will lead to the identification of gene(s) responsible for HAPE and possibly other maladaptive hypoxic complications. PMID:19481479

  20. Tibetan and Andean contrasts in adaptation to high-altitude hypoxia.

    PubMed

    Beall, C M

    2000-01-01

    High-altitude environments provide natural experimental settings to investigate adaptation to environmental stress. An important evolutionary and functional question is whether sea-level human biology constrains the adaptive response. This paper presents evidence that indigenous populations of the Tibetan and Andean plateaus exhibit quantitatively different responses to hypobaric hypoxic stress. At the same altitude, Tibetan mean resting ventilation and hypoxic ventilatory response were more than one-half standard deviation higher than Andean Aymara means while Tibetan mean oxygen saturation and hemoglobin concentration were more than one standard deviation below the Andean means. Quantitative genetic analyses of the familial patterning of these traits provided indirect evidence of population differences in genes influencing them. The Tibetan and Andean patterns of oxygen transport appear equally effective functionally as evaluated by birthweight and maximal aerobic capacity across a range of altitudes.

  1. Ventilation during simulated altitude, normobaric hypoxia and normoxic hypobaria

    NASA Technical Reports Server (NTRS)

    Loeppky, J. A.; Icenogle, M.; Scotto, P.; Robergs, R.; Hinghofer-Szalkay, H.; Roach, R. C.; Leoppky, J. A. (Principal Investigator)

    1997-01-01

    To investigate the possible effect of hypobaria on ventilation (VE) at high altitude, we exposed nine men to three conditions for 10 h in a chamber on separate occasions at least 1 week apart. These three conditions were: altitude (PB = 432, FIO2 = 0.207), normobaric hypoxia (PB = 614, FIO2 = 0.142) and normoxic hypobaria (PB = 434, FIO2 = 0.296). In addition, post-test measurements were made 2 h after returning to ambient conditions at normobaric normoxia (PB = 636, FIO2 = 0.204). In the first hour of exposure VE was increased similarly by altitude and normobaric hypoxia. The was 38% above post-test values and end-tidal CO2 (PET(CO2) was lower by 4 mmHg. After 3, 6 and 9 h, the average VE in normobaric hypoxia was 26% higher than at altitude (p < 0.01), resulting primarily from a decline in VE at altitude. The difference between altitude and normobaric hypoxia was greatest at 3 h (+ 39%). In spite of the higher VE during normobaric hypoxia, the PET(CO2) was higher than at altitude. Changes in VE and PET(CO2) in normoxic hypobaria were minimal relative to normobaric normoxia post-test measurements. One possible explanation for the lower VE at altitude is that CO2 elimination is relatively less at altitude because of a reduction in inspired gas density compared to normobaric hypoxia; this may reduce the work of breathing or alveolar deadspace. The greater VE during the first hour at altitude, relative to subsequent measurements, may be related to the appearance of microbubbles in the pulmonary circulation acting to transiently worsen matching. Results indicate that hypobaria per se effects ventilation under altitude conditions.

  2. Cerebral spinal fluid dynamics: effect of hypoxia and implications for high-altitude illness.

    PubMed

    Lawley, Justin S; Levine, Benjamin D; Williams, Michael A; Malm, Jon; Eklund, Anders; Polaner, David M; Subudhi, Andrew W; Hackett, Peter H; Roach, Robert C

    2016-01-15

    The pathophysiology of acute mountain sickness and high-altitude cerebral edema, the cerebral forms of high-altitude illness, remain uncertain and controversial. Persistently elevated or pathological fluctuations in intracranial pressure are thought to cause symptoms similar to those reported by individuals suffering cerebral forms of high-altitude illness. This review first focuses on the basic physiology of the craniospinal system, including a detailed discussion of the long-term and dynamic regulation of intracranial pressure. Thereafter, we critically examine the available literature, based primarily on invasive pressure monitoring, that suggests intracranial pressure is acutely elevated at altitude due to brain swelling and/or elevated sagittal sinus pressure, but normalizes over time. We hypothesize that fluctuations in intracranial pressure occur around a slightly elevated or normal mean intracranial pressure, in conjunction with oscillations in arterial Po2 and arterial blood pressure. Then these modest fluctuations in intracranial pressure, in concert with direct vascular stretch due to dilatation and/or increased blood pressure transmission, activate the trigeminal vascular system and cause symptoms of acute mountain sickness. Elevated brain water (vasogenic edema) may be due to breakdown of the blood-brain barrier. However, new information suggests cerebral spinal fluid flux into the brain may be an important factor. Regardless of the source (or mechanisms responsible) for the excess brain water, brain swelling occurs, and a "tight fit" brain would be a major risk factor to produce symptoms; activities that produce large changes in brain volume and cause fluctuations in blood pressure are likely contributing factors.

  3. Correlation between single nucleotide polymorphisms in hypoxia-related genes and susceptibility to acute high-altitude pulmonary edema.

    PubMed

    Wu, A L; Xiong, Y S; Li, Z Q; Liu, Y G; Quan, Q; Wu, L J

    2015-01-01

    This study aimed to explore the relationship between genetic changes and high-altitude pulmonary edema (HAPE) susceptibility, and to screen for the key single nucleotide polymorphism (SNP) loci in the HAPE-susceptibility gene, by investigating the SNPs occurring in hypoxia-related genes in HAPE-susceptible and control (non-susceptible) populations. This research was conducted on Han recruits, who travelled to the Lhasa plateau (altitude, 3658 m). Ten loci located on ten genes extracted from the HAPE and healthy populations were amplified by polymerase chain reaction, and subsequently sequenced. The investigated genes included those coding for aldosterone synthase 2 (CYP11B2), angiotensin-converting enzyme (ACE), heat-shock protein 70 (HSP70), nuclear factor kappa B (NF-κB), surfactant protein A2 (SP-A2), plasminogen activator inhibitor-1 (PAI-1), nitric oxide synthetase (NOS), vascular endothelial growth factor (VEGF), prolyl hydroxylase (EGLN1), and zinc finger protein A20. The gene distribution of each SNP loci and its correlation with HAPE was analyzed. Statistical analyses of the genotype frequencies of the SNPs revealed significant differences in the ACE (rs4309), EGLN1 (rs480902), SP-A2 (rs1965708), HSP70 (rs1008438), PAI-1 (rs1799889), and NOS (rs199983) expressions between the HAPE and healthy control groups (P < 0.05); therefore, these SNP loci were believed to indicate HAPE susceptibility. HAPE is correlated with multiple- SNP loci. A correlation analysis between genetic polymorphism and HAPE susceptibility revealed that 6 hypoxia-related genes were key sites accounting for HAPE. These findings could help assess the risk of HAPE in populations expressing different genotypes, in order to reduce the occurrence of HAPE. PMID:26436397

  4. Cardiovascular medicine at high altitude.

    PubMed

    Whayne, Thomas F

    2014-07-01

    Altitude physiology began with Paul Bert in 1878. Chronic mountain sickness (CMS) was defined by Carlos Monge in the 1940s in the Peruvian Andes as consisting of excess polycythemia. Hurtado et al performed studies in the Peruvian Andes in the 1950s to 1960s which defined acclimatization in healthy altitude natives, including polycythemia, moderate pulmonary hypertension, and low systemic blood pressure (BP). Electrocardiographic changes of right ventricular hypertrophy (RVH) were noted. Acclimatization of newcomers to altitude involves hyperventilation stimulated by hypoxia and is usually benign. Acute mountain sickness (AMS) in travelers to altitude is characterized by hypoxia-induced anorexia, dyspnea, headache, insomnia, and nausea. The extremes of AMS are high-altitude cerebral edema and high-altitude pulmonary edema. The susceptible high-altitude resident can lose their tolerance to altitude and develop CMS, also referred to as Monge disease. The CMS includes extreme polycythemia, severe RVH, excess pulmonary hypertension, low systemic BP, arterial oxygen desaturation, and hypoventilation.

  5. Brain Food at High Altitude.

    PubMed

    Jain, Vishal

    2016-01-01

    Scenic view at high altitude is a pleasure to the eyes, but it has some shortcoming effects as well. High altitude can be divided into different categories, i.e., high altitude (3000-5000 ft), very high altitude (5000-8000 ft), and extreme altitude (above 8000 ft). Much of the population resides at high altitude, and others go there for tourism. Military personnel are also posted there to defend boundaries. As we ascent to high altitude, partial pressure of oxygen reduces, whereas concentration remains the same; this reduces the availability of oxygen to different body parts. This pathophysiological condition is known as hypobaric hypoxia (HH) which leads to oxidative stress and further causes cognitive dysfunction in some cases. Hypoxia causes neurodegeneration in different brain regions; however, the hippocampus is found to be more prone in comparison to other brain regions. As the hippocampus is affected most, therefore, spatial memory is impaired most during such condition. This chapter will give a brief review of the damaging effect of high altitude on cognition and also throw light on possible herbal interventions at high altitude, which can improve cognitive performance as well as provide protection against the deteriorating effect of hypobaric hypoxia at high altitude.

  6. Brain Food at High Altitude.

    PubMed

    Jain, Vishal

    2016-01-01

    Scenic view at high altitude is a pleasure to the eyes, but it has some shortcoming effects as well. High altitude can be divided into different categories, i.e., high altitude (3000-5000 ft), very high altitude (5000-8000 ft), and extreme altitude (above 8000 ft). Much of the population resides at high altitude, and others go there for tourism. Military personnel are also posted there to defend boundaries. As we ascent to high altitude, partial pressure of oxygen reduces, whereas concentration remains the same; this reduces the availability of oxygen to different body parts. This pathophysiological condition is known as hypobaric hypoxia (HH) which leads to oxidative stress and further causes cognitive dysfunction in some cases. Hypoxia causes neurodegeneration in different brain regions; however, the hippocampus is found to be more prone in comparison to other brain regions. As the hippocampus is affected most, therefore, spatial memory is impaired most during such condition. This chapter will give a brief review of the damaging effect of high altitude on cognition and also throw light on possible herbal interventions at high altitude, which can improve cognitive performance as well as provide protection against the deteriorating effect of hypobaric hypoxia at high altitude. PMID:27651260

  7. Cardiovascular physiology at high altitude.

    PubMed

    Hooper, T; Mellor, A

    2011-03-01

    The role of the cardiovascular system is to deliver oxygenated blood to the tissues and remove metabolic effluent. It is clear that this complex system will have to adapt to maintain oxygen deliver in the profound hypoxia of high altitude. The literature on the adaptation of both the systemic and pulmonary circulations to high altitude is reviewed. PMID:21465906

  8. Cardiovascular physiology at high altitude.

    PubMed

    Hooper, T; Mellor, A

    2011-03-01

    The role of the cardiovascular system is to deliver oxygenated blood to the tissues and remove metabolic effluent. It is clear that this complex system will have to adapt to maintain oxygen deliver in the profound hypoxia of high altitude. The literature on the adaptation of both the systemic and pulmonary circulations to high altitude is reviewed.

  9. Cognitive impairments at high altitudes and adaptation.

    PubMed

    Yan, Xiaodan

    2014-06-01

    High altitude hypoxia has been shown to have significant impact on cognitive performance. This article reviews the aspects in which, and the conditions under which, decreased cognitive performance has been observed at high altitudes. Neural changes related to high altitude hypoxia are also reviewed with respect to their possible contributions to cognitive impairments. In addition, potential adaptation mechanisms are reviewed among indigenous high altitude residents and long-term immigrant residents, with discussions about methodological concerns related to these studies.

  10. A genetic response to high altitude hypoxia: high hemoglobin-oxygen affinity in chicken (Gallus gallus) from the Peruvian Andes.

    PubMed

    Velarde, F L; Espinoza, D; Monge, C; de Muizon, C

    1991-01-01

    A population of chicken (Gallus gallus) from the Peruvian Andes (4,000 m) carrying a high hemoglobin-oxygen affinity has been identified. This property remained stable after over 1 year residence at sea level and was transmitted to the descendants born at sea level. Chicken were introduced in South America during the Spanish conquest and therefore their adaptation time to high altitude is less than 500 years. This finding shows that a genotypic change in hemoglobin function can occur in an extremely short evolutionary time and leads to some reflections on the high altitude adaptation of the mammals that migrated to South America during the great Plio-Pleistocene interchange.

  11. Endothelin receptor B, a candidate gene from human studies at high altitude, improves cardiac tolerance to hypoxia in genetically engineered heterozygote mice.

    PubMed

    Stobdan, Tsering; Zhou, Dan; Ao-Ieong, Eilleen; Ortiz, Daniel; Ronen, Roy; Hartley, Iain; Gan, Zhuohui; McCulloch, Andrew D; Bafna, Vineet; Cabrales, Pedro; Haddad, Gabriel G

    2015-08-18

    To better understand human adaptation to stress, and in particular to hypoxia, we took advantage of one of nature's experiments at high altitude (HA) and studied Ethiopians, a population that is well-adapted to HA hypoxic stress. Using whole-genome sequencing, we discovered that EDNRB (Endothelin receptor type B) is a candidate gene involved in HA adaptation. To test whether EDNRB plays a critical role in hypoxia tolerance and adaptation, we generated EdnrB knockout mice and found that when EdnrB (-/+) heterozygote mice are treated with lower levels of oxygen (O2), they tolerate various levels of hypoxia (even extreme hypoxia, e.g., 5% O2) very well. For example, they maintain ejection fraction, cardiac contractility, and cardiac output in severe hypoxia. Furthermore, O2 delivery to vital organs was significantly higher and blood lactate was lower in EdnrB (-/+) compared with wild type in hypoxia. Tissue hypoxia in brain, heart, and kidney was lower in EdnrB (-/+) mice as well. These data demonstrate that a lower level of EDNRB significantly improves cardiac performance and tissue perfusion under various levels of hypoxia. Transcriptomic profiling of left ventricles revealed three specific genes [natriuretic peptide type A (Nppa), sarcolipin (Sln), and myosin light polypeptide 4 (Myl4)] that were oppositely expressed (q < 0.05) between EdnrB (-/+) and wild type. Functions related to these gene networks were consistent with a better cardiac contractility and performance. We conclude that EDNRB plays a key role in hypoxia tolerance and that a lower level of EDNRB contributes, at least in part, to HA adaptation in humans.

  12. Endothelin receptor B, a candidate gene from human studies at high altitude, improves cardiac tolerance to hypoxia in genetically engineered heterozygote mice

    PubMed Central

    Stobdan, Tsering; Zhou, Dan; Ao-Ieong, Eilleen; Ortiz, Daniel; Ronen, Roy; Hartley, Iain; Gan, Zhuohui; McCulloch, Andrew D.; Bafna, Vineet; Cabrales, Pedro; Haddad, Gabriel G.

    2015-01-01

    To better understand human adaptation to stress, and in particular to hypoxia, we took advantage of one of nature’s experiments at high altitude (HA) and studied Ethiopians, a population that is well-adapted to HA hypoxic stress. Using whole-genome sequencing, we discovered that EDNRB (Endothelin receptor type B) is a candidate gene involved in HA adaptation. To test whether EDNRB plays a critical role in hypoxia tolerance and adaptation, we generated EdnrB knockout mice and found that when EdnrB−/+ heterozygote mice are treated with lower levels of oxygen (O2), they tolerate various levels of hypoxia (even extreme hypoxia, e.g., 5% O2) very well. For example, they maintain ejection fraction, cardiac contractility, and cardiac output in severe hypoxia. Furthermore, O2 delivery to vital organs was significantly higher and blood lactate was lower in EdnrB−/+ compared with wild type in hypoxia. Tissue hypoxia in brain, heart, and kidney was lower in EdnrB−/+ mice as well. These data demonstrate that a lower level of EDNRB significantly improves cardiac performance and tissue perfusion under various levels of hypoxia. Transcriptomic profiling of left ventricles revealed three specific genes [natriuretic peptide type A (Nppa), sarcolipin (Sln), and myosin light polypeptide 4 (Myl4)] that were oppositely expressed (q < 0.05) between EdnrB−/+ and wild type. Functions related to these gene networks were consistent with a better cardiac contractility and performance. We conclude that EDNRB plays a key role in hypoxia tolerance and that a lower level of EDNRB contributes, at least in part, to HA adaptation in humans. PMID:26240367

  13. [Effects of palmitic acid on activity of uncoupling proteins and proton leak in in vitro cerebral mitochondria from the rats exposed to simulated high altitude hypoxia].

    PubMed

    Xu, Yu; Liu, Jun-Ze; Xia, Chen

    2008-02-25

    To reveal the roles of uncoupling proteins (UCPs) in disorder of mitochondrial oxidative phosphorylation induced by free fatty acid during hypoxic exposure, the effects of palmitic acid on activity of UCPs, proton leak and mitochondrial membrane potential in hypoxia-exposed rat brain mitochondria were observed in vitro. Adult Sprague-Dawley (SD) rats were set randomly into control, acute hypoxia and chronic hypoxia groups (n=8 in each group). The acute and chronic hypoxic rats were exposed to simulated 5000 m high altitude in a hypobaric chamber 23 h/d for 3 d and 30 d, respectively. The brain mitochondria were isolated by centrifugation. UCP content and activity were detected by [(3)H]-GTP binding method. The proton leak was measured by TPMP(+) electrode and oxygen electrode. The membrane potential of mitochondria was calculated by detecting the fluorescence from Rodamine 123. Hypoxic exposure resulted in an increase in UCP activity and content as well as proton leak, but a decrease in the membrane potential of rat brain mitochondria. Palmitic acid resulted in further increases in UCP activity and content as well as proton leak, and further decrease in membrane potential of brain mitochondria in vitro from hypoxia-exposed rats, but hypoxic exposure decreased the reactivity of cerebral mitochondria to palmitic acid, especially in the acute hypoxia group. There was a negative correlation between mitochondrial proton leak and K(d) value (representing derivative of UCP activity, P<0.01, r = -0.906), and a positive correlation between proton leak and B(max) (representing the maximal content of UCPs in mitochondrial inner membrane, P<0.01, r = 0.856). Cerebral mitochondrial membrane potential was negatively correlated with proton leak (P<0.01, r = -0.880). It is suggested that hypoxia-induced proton leak enhancement and membrane potential decrease are correlated with the increased activity of UCPs. Hypoxia can also decrease the sensitivity of cerebral mitochondria to

  14. Exposure to Hypoxia at High Altitude (5380 m) for 1 Year Induces Reversible Effects on Semen Quality and Serum Reproductive Hormone Levels in Young Male Adults.

    PubMed

    He, Jiang; Cui, Jianhua; Wang, Rui; Gao, Liang; Gao, Xiaokang; Yang, Liu; Zhang, Qiong; Cao, Jinjun; Yu, Wuzhong

    2015-09-01

    This study investigated the effect of hypoxia at high altitude on the semen quality and the serum reproductive hormone levels in male adults. A total of 52 male soldiers were enrolled in this cohort study. They were exposed to hypoxia at high altitude (5380 m) for 12 months when undergoing a service. After exposure, they were followed up for 6 months. The samples of semen and peripheral blood were collected at 1 month before exposure (M0), 6 months of exposure (M6), 12 months of exposure (M12), and 6 months after exposure (M18). The semen quality was assessed with computer-assisted analysis system, and the serum levels of reproductive hormones, including prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone were analyzed by ELISA. Compared with those at M0, total sperm count, sperm density, motility, survival rate, and serum levels of LH, PRL and testosterone were significantly decreased, whereas the liquefaction time was significantly prolonged and serum FSH level was significantly increased at M6 (p<0.05). At M12, total sperm count and sperm density increased, whereas sperm motility, survival rate, and the liquefaction time further decreased. Sperm velocities, progression ratios, and lateral head displacements were also decreased. Serum FSH level decreased while serum LH, PRL, and testosterone levels increased. Compared with those at M6, the changes in these detected parameters of semen and hormone at M12 were significant (p<0.05). At M18, all these detected parameters except testosterone level returned to levels comparable to those before exposure. In conclusion, hypoxia at high altitude causes adverse effects on semen quality and reproductive hormones, and these effects are reversible.

  15. Cardiovascular medicine at high altitude.

    PubMed

    Whayne, Thomas F

    2014-07-01

    Altitude physiology began with Paul Bert in 1878. Chronic mountain sickness (CMS) was defined by Carlos Monge in the 1940s in the Peruvian Andes as consisting of excess polycythemia. Hurtado et al performed studies in the Peruvian Andes in the 1950s to 1960s which defined acclimatization in healthy altitude natives, including polycythemia, moderate pulmonary hypertension, and low systemic blood pressure (BP). Electrocardiographic changes of right ventricular hypertrophy (RVH) were noted. Acclimatization of newcomers to altitude involves hyperventilation stimulated by hypoxia and is usually benign. Acute mountain sickness (AMS) in travelers to altitude is characterized by hypoxia-induced anorexia, dyspnea, headache, insomnia, and nausea. The extremes of AMS are high-altitude cerebral edema and high-altitude pulmonary edema. The susceptible high-altitude resident can lose their tolerance to altitude and develop CMS, also referred to as Monge disease. The CMS includes extreme polycythemia, severe RVH, excess pulmonary hypertension, low systemic BP, arterial oxygen desaturation, and hypoventilation. PMID:23892441

  16. Lung Disease at High Altitude

    PubMed Central

    Stream, JO; Luks, AM; Grissom, CK

    2016-01-01

    Large numbers of people travel to high altitudes, entering an environment of hypobaric hypoxia. Exposure to low oxygen tension leads to a series of important physiologic responses that allow individuals to tolerate these hypoxic conditions. However, in some cases hypoxia triggers maladaptive responses that lead to various forms of acute and chronic high altitude illness, such as high-altitude pulmonary edema or chronic mountain sickness. Because the respiratory system plays a critical role in these adaptive and maladaptive responses, patients with underlying lung disease may be at increased risk for complications in this environment and warrant careful evaluation before any planned sojourn to higher altitudes. In this review, we describe respiratory disorders that occur with both acute and chronic exposures to high altitudes. These disorders may occur in any individual who ascends to high altitude, regardless of his/her baseline pulmonary status. We then consider the safety of high-altitude travel in patients with various forms of underlying lung disease. The available data regarding how these patients fare in hypoxic conditions are reviewed, and recommendations are provided for management prior to and during the planned sojourn. PMID:20477353

  17. Infectious Diseases at High Altitude.

    PubMed

    Basnyat, Buddha; Starling, Jennifer M

    2015-08-01

    Travel to elevations above 2,500 m is an increasingly common activity undertaken by a diverse population of individuals. These may be trekkers, climbers, miners in high-altitude sites in South America, and more recently, soldiers deployed for high-altitude duty in remote areas of the world. What is also being increasingly recognized is the plight of the millions of pilgrims, many with comorbidities, who annually ascend to high-altitude sacred areas. There are also 400 million people who reside permanently in high mountain ranges, which cover one-fifth of the Earth's surface. Many of these high-altitude areas are in developing countries, for example, the Himalayan range in South Asia. Although high-altitude areas may not harbor any specific infectious disease agents, it is important to know about the pathogens encountered in the mountains to be better able to help both the ill sojourner and the native high-altitude dweller. Often the same pathogens prevalent in the surrounding lowlands are found at high altitude, but various factors such as immunomodulation, hypoxia, poor physiological adaptation, and harsh environmental stressors at high altitude may enhance susceptibility to these pathogens. Against this background, various gastrointestinal, respiratory, dermatological, neurological, and other infections encountered at high altitude are discussed.

  18. High-Altitude Illness

    MedlinePlus

    ... altitude illness: Acute mountain sickness High-altitude pulmonary edema (also called HAPE), which affects the lungs High-altitude cerebral edema (also called HACE), which affects the brain These ...

  19. Mitochondrial DNA 10609T promotes hypoxia-induced increase of intracellular ROS and is a risk factor of high altitude polycythemia.

    PubMed

    Jiang, Chunhua; Cui, Jianhua; Liu, Fuyu; Gao, Liang; Luo, Yongjun; Li, Peng; Guan, Libin; Gao, Yuqi

    2014-01-01

    Hypobaric hypoxia is the primary cause of high altitude polycythemia (HAPC). Mitochondria are critical organelles that consume high levels of oxygen and generate ATP. We hypothesize that the mitochondrion may be at the center of HAPC, and mitochondrial DNA (mtDNA) SNPs may be involved in its development. First, we conducted a case-control study to investigate the association of mtDNA variants with HAPC in Han Chinese migrating to the Qinghai-Tibetan Plateau. Pearson's chi-square tests revealed that mtDNA 8414T (MU) frequency (19.5%) in the HAPC group was significantly higher than that of the control (13.0%, P = 0.04, OR = 1.615, 95%CI: 1.020-2.555). The multivariate logistic regression analysis, after adjustment for environmental factors, revealed that mtDNA 10609T (WT) was significantly associated with an increased risk of HAPC (P<0.01, OR = 2.558, 95%CI: 1.250-5.236). Second, to verify the association, in vitro experiments of transmitochondrial cybrids was performed and revealed that the mtDNA 10609 variant promoted hypoxia-induced increase of intracellular ROS, but the mtDNA 8414 variant did not. Our findings provide evidence that, in Han Chinese, mtDNA 10609T promotes hypoxia-induced increase of intracellular ROS and is a HAPC risk factor.

  20. Effect of Acute Exposure to Moderate Altitude on Muscle Power: Hypobaric Hypoxia vs. Normobaric Hypoxia

    PubMed Central

    Feriche, Belén; García-Ramos, Amador; Calderón-Soto, Carmen; Drobnic, Franchek; Bonitch- Góngora, Juan G.; Galilea, Pedro A.; Riera, Joan; Padial, Paulino

    2014-01-01

    When ascending to a higher altitude, changes in air density and oxygen levels affect the way in which explosive actions are executed. This study was designed to compare the effects of acute exposure to real or simulated moderate hypoxia on the dynamics of the force-velocity relationship observed in bench press exercise. Twenty-eight combat sports athletes were assigned to two groups and assessed on two separate occasions: G1 (n = 17) in conditions of normoxia (N1) and hypobaric hypoxia (HH) and G2 (n = 11) in conditions of normoxia (N2) and normobaric hypoxia (NH). Individual and complete force-velocity relationships in bench press were determined on each assessment day. For each exercise repetition, we obtained the mean and peak velocity and power shown by the athletes. Maximum power (Pmax) was recorded as the highest Pmean obtained across the complete force-velocity curve. Our findings indicate a significantly higher absolute load linked to Pmax (∼3%) and maximal strength (1RM) (∼6%) in G1 attributable to the climb to altitude (P<0.05). We also observed a stimulating effect of natural hypoxia on Pmean and Ppeak in the middle-high part of the curve (≥60 kg; P<0.01) and a 7.8% mean increase in barbell displacement velocity (P<0.001). No changes in any of the variables examined were observed in G2. According to these data, we can state that acute exposure to natural moderate altitude as opposed to simulated normobaric hypoxia leads to gains in 1RM, movement velocity and power during the execution of a force-velocity curve in bench press. PMID:25474104

  1. Effect of acute exposure to moderate altitude on muscle power: hypobaric hypoxia vs. normobaric hypoxia.

    PubMed

    Feriche, Belén; García-Ramos, Amador; Calderón-Soto, Carmen; Drobnic, Franchek; Bonitch-Góngora, Juan G; Galilea, Pedro A; Riera, Joan; Padial, Paulino

    2014-01-01

    When ascending to a higher altitude, changes in air density and oxygen levels affect the way in which explosive actions are executed. This study was designed to compare the effects of acute exposure to real or simulated moderate hypoxia on the dynamics of the force-velocity relationship observed in bench press exercise. Twenty-eight combat sports athletes were assigned to two groups and assessed on two separate occasions: G1 (n = 17) in conditions of normoxia (N1) and hypobaric hypoxia (HH) and G2 (n = 11) in conditions of normoxia (N2) and normobaric hypoxia (NH). Individual and complete force-velocity relationships in bench press were determined on each assessment day. For each exercise repetition, we obtained the mean and peak velocity and power shown by the athletes. Maximum power (Pmax) was recorded as the highest P(mean) obtained across the complete force-velocity curve. Our findings indicate a significantly higher absolute load linked to P(max) (∼ 3%) and maximal strength (1 RM) (∼ 6%) in G1 attributable to the climb to altitude (P<0.05). We also observed a stimulating effect of natural hypoxia on P(mean) and P(peak) in the middle-high part of the curve (≥ 60 kg; P<0.01) and a 7.8% mean increase in barbell displacement velocity (P<0.001). No changes in any of the variables examined were observed in G2. According to these data, we can state that acute exposure to natural moderate altitude as opposed to simulated normobaric hypoxia leads to gains in 1 RM, movement velocity and power during the execution of a force-velocity curve in bench press.

  2. Yak response to high-altitude hypoxic stress by altering mRNA expression and DNA methylation of hypoxia-inducible factors.

    PubMed

    Xiong, Xianrong; Fu, Mei; Lan, Daoliang; Li, Jian; Zi, Xiangdong; Zhong, Jincheng

    2015-01-01

    Hypoxia-inducible factors (HIFs) are oxygen-dependent transcriptional activators, which play crucial roles in tumor angiogenesis and mammalian development, and regulate the transcription of genes involved in oxygen homeostasis in response to hypoxia. However, information on HIF-1α and HIF-2α in yak (Bos grunniens) is scarce. The complete coding region of yak HIF-2α was cloned, its mRNA expression in several tissues were determined, and the expression levels were compared with those of closely related low-altitude cattle (Bos taurus), and the methylation status of promoter regions were analyzed to better understand the roles of HIF-1α and HIF-2α in domesticated yak. The yak HIF-2α cDNA was cloned and sequenced in the present work reveals the evolutionary conservation through multiple sequence alignment, although 15 bases changed, resulting in 8 amino acid substitutions in the translated proteins in cattle. The tissue-specific expression results showed that HIF-1α is ubiquitously expressed, whereas HIF-2α expression is limited to endothelial tissues (kidney, heart, lung, spleen, and liver) and blood in yak. Both HIF-1α and HIF-2α expressions were higher in yak tissues than in cattle. The HIF-1α expression level is much higher in yak than cattle in these organs, except for the lung (P < 0.05), but the HIF-2α gene is significantly different in the heart, spleen, and kidney (P < 0.05). Furthermore, the methylation levels in the 5' flanking regulatory regions of HIF-1α and HIF-2α in yak kidney were significantly decreased than cattle counterparts (P < 0.05). Identifying these genes and the comparison of different expressions facilitates the understanding of the biological high-altitude hypoxic stress response mechanism and may assist current medical research to understand hypoxia-related diseases. PMID:25927169

  3. Effect of intermittent hypoxia on the reproduction of rats exposed to high altitude in the Chilean Altiplano.

    PubMed

    Cikutovic, Marcos; Fuentes, Nelson; Bustos-Obregón, Eduardo

    2009-01-01

    Environmental parameters such as the large day-night temperature differences, high light radiation, and low humidity may have a synergistic effect with low oxygen pressure. To evaluate the effects of the exposure to intermittent chronic hypobaric hypoxia (ICHH) in nature on rat reproduction, a group of rats was alternately moved to a location at 3400 meters over sea level (moml) for 7 days and returned the subsequent week to sea level; this procedure was repeated six times. Hematological and reproductive parameters were measured and analyzed. At the end of the experimental protocol, hematocrit and hemoglobin concentrations were significantly greater in the ICHH group compared to the control group (Nx) (p < 0.05). The diameter of the seminiferous tubule and the height of the spermatogenic epithelium in ICHH rats presented a significant decrease in relation to Nx rats (p < 0.05). Consequently, the number of epididymal spermatozoa in the experimental animals decreased compared to normal rats, with no evidence of recovery after 84 days. The offspring of the different matings between normal and hypoxic animals decreased proportionally to hypoxia exposure. The low oxygen and the changes in testicular temperature homeostasis would provide a novel local mechanism to explain the decrease in sperm cell production and the reduced number of puppies born. The alterations of the reproductive parameters of the hypoxic female, plus testicular injuries and diminished sperm in males, result in a significant decrease in the reproductive activity of the animals.

  4. Genome Resequencing Identifies Unique Adaptations of Tibetan Chickens to Hypoxia and High-Dose Ultraviolet Radiation in High-Altitude Environments

    PubMed Central

    Zhang, Qian; Gou, Wenyu; Wang, Xiaotong; Zhang, Yawen; Ma, Jun; Zhang, Hongliang; Zhang, Ying; Zhang, Hao

    2016-01-01

    Tibetan chicken, unlike their lowland counterparts, exhibit specific adaptations to high-altitude conditions. The genetic mechanisms of such adaptations in highland chickens were determined by resequencing the genomes of four highland (Tibetan and Lhasa White) and four lowland (White Leghorn, Lindian, and Chahua) chicken populations. Our results showed an evident genetic admixture in Tibetan chickens, suggesting a history of introgression from lowland gene pools. Genes showing positive selection in highland populations were related to cardiovascular and respiratory system development, DNA repair, response to radiation, inflammation, and immune responses, indicating a strong adaptation to oxygen scarcity and high-intensity solar radiation. The distribution of allele frequencies of nonsynonymous single nucleotide polymorphisms between highland and lowland populations was analyzed using chi-square test, which showed that several differentially distributed genes with missense mutations were enriched in several functional categories, especially in blood vessel development and adaptations to hypoxia and intense radiation. RNA sequencing revealed that several differentially expressed genes were enriched in gene ontology terms related to blood vessel and respiratory system development. Several candidate genes involved in the development of cardiorespiratory system (FGFR1, CTGF, ADAM9, JPH2, SATB1, BMP4, LOX, LPR, ANGPTL4, and HYAL1), inflammation and immune responses (AIRE, MYO1F, ZAP70, DDX60, CCL19, CD47, JSC, and FAS), DNA repair, and responses to radiation (VCP, ASH2L, and FANCG) were identified to play key roles in the adaptation to high-altitude conditions. Our data provide new insights into the unique adaptations of highland animals to extreme environments. PMID:26907498

  5. ZFP580, a Novel Zinc-Finger Transcription Factor, Is Involved in Cardioprotection of Intermittent High-Altitude Hypoxia against Myocardial Ischemia-Reperfusion Injury

    PubMed Central

    Zhang, Wen-cheng; Wang, Tian-hui; Mai, Xia; Liu, Hong-tao; Xu, Rui-cheng

    2014-01-01

    Background ZFP580 is a novel C2H2 type zinc-finger transcription factor recently identified by our laboratory. We previously showed that ZFP580 may be involved in cell survival and growth. The aim of this study was to elucidate whether ZFP580 is involved in the cardioprotective effects of intermittent high-altitude (IHA) hypoxia against myocardial ischemia-reperfusion (I/R) injury. Methods and Results After rats were subjected to myocardial ischemia for 30 min followed by reperfusion, ZFP580 expression in the left ventricle was measured. ZFP580 protein expression was found to be up-regulated within 1 h and decreased at 2 h after reperfusion. Comparing normoxic and IHA hypoxia-adapted rats (5000 m, 6 h day−1, 6 weeks) following I/R injury (30 min ischemia and 2 h reperfusion), we found that adaptation to IHA hypoxia attenuated infarct size and plasma leakage of lactate dehydrogenase and creatine kinase-MB. In addition, ZFP580 expression in the myocardium was up-regulated by IHA hypoxia. Consistent with this result, ZFP580 expression was found to be significantly increased in cultured H9c2 myocardial cells in the hypoxic preconditioning group compared with those in the control group following simulated I/R injury (3 h simulated ischemic hypoxia and 2 h reoxygenation). To determine the role of ZFP580 in apoptosis, lentivirus-mediated gene transfection was performed in H9c2 cells 72 h prior to simulated I/R exposure. The results showed that ZFP580 overexpression significantly inhibited I/R-induced apoptosis and caspase-3 activation. H9c2 cells were pretreated with or without PD98059, an inhibitor of ERK1/2 phosphorylation, and Western blot results showed that PD98059 (10 µM) markedly suppressed I/R-induced up-regulation of ZFP580 expression. Conclusions Our findings demonstrate that the cardioprotective effect of IHA hypoxia against I/R injury is mediated via ZFP580, a downstream target of ERK1/2 signaling with anti-apoptotic roles in myocardial cells. PMID:24722354

  6. Sleep and Breathing at High Altitude.

    PubMed

    Wickramasinghe, Himanshu; Anholm, James D.

    1999-01-01

    Sleep at high altitude is characterized by poor subjective quality, increased awakenings, frequent brief arousals, marked nocturnal hypoxemia, and periodic breathing. A change in sleep architecture with an increase in light sleep and decreasing slow-wave and REM sleep have been demonstrated. Periodic breathing with central apnea is almost universally seen amongst sojourners to high altitude, although it is far less common in long-standing high altitude dwellers. Hypobaric hypoxia in concert with periodic breathing appears to be the principal cause of sleep disruption at altitude. Increased sleep fragmentation accounts for the poor sleep quality and may account for some of the worsened daytime performance at high altitude. Hypoxic sleep disruption contributes to the symptoms of acute mountain sickness. Hypoxemia at high altitude is most severe during sleep. Acetazolamide improves sleep, AMS symptoms, and hypoxemia at high altitude. Low doses of a short acting benzodiazepine (temazepam) may also be useful in improving sleep in high altitude. PMID:11898114

  7. Fulminant high altitude blindness.

    PubMed

    Mashkovskiy, Evgeny; Szawarski, Piotr; Ryzhkov, Pavel; Goslar, Tomaz; Mrak, Irena

    2016-06-01

    Prolonged altitude exposure even with acclimatization continues to present a physiological challenge to all organ systems including the central nervous system. We describe a case of a 41-year-old Caucasian female climber who suffered severe visual loss that was due to possible optic nerve pathology occurring during a high altitude expedition in the Himalayas. This case is atypical of classic high altitude cerebral oedema and highlights yet another danger of prolonged sojourn at extreme altitudes. PMID:27601532

  8. Effects on the rabbit carotid body of stimulation by almitrine, natural high altitude, and experimental normobaric hypoxia.

    PubMed

    Smith, P; Heath, D; Fitch, R; Hurst, G; Moore, D; Weitzenblum, E

    1986-06-01

    Rabbits were given intraperitoneal injections of almitrine in ascending doses for 5 weeks. They were compared with a control group and with a group of rabbits which had been exposed from birth to the natural hypobaric hypoxia found at Cerro de Pasco (433 m) in the Peruvian Andes. A further group of animals was placed in an experimental normobaric chamber for either 3 or 6 months to subject them to the same degree of hypoxia as that occurring in Cerro. The carotid bodies of the rabbits in all these groups were processed for light and electron microscopy, and examined both qualitatively and quantitatively. The carotid bodies in the group given almitrine showed no changes in their size or in the population of their glomic cells when compared with controls. In contrast, the carotid bodies of Peruvian rabbits were greatly enlarged with a disproportionate increase in the population of the light variant of chief cell. Rabbits from the hypoxic chamber also had enlarged carotid bodies but those killed after 3 months showed an increase in the dark variant of chief cell, whereas after 6 months this cell was reduced in number. There was also intense cytoplasmic vacuolation. Election microscopy confirmed these changes and revealed that dark cells had larger, more pleomorphic granules than the light variant. Vacuolation of the granules in light cells was most pronounced in Peruvian rabbits, but was uncommon in animals exposed to hypoxia for 3 months. We suggest that the dark cell responds to the early stages of hypoxia but later matures into the light variant of chief cell.

  9. CRHR1 mediates p53 transcription induced by high altitude hypoxia through ERK 1/2 signaling in rat hepatic cells.

    PubMed

    Zhao, Yang; Wang, Ming-Yang; Hao, Ke; Chen, Xue-Qun; Du, Ji-Zeng

    2013-06-01

    We have previously reported that hypoxia activates corticotrophin-releasing hormone (CRH) and the expression of its type-1 receptor (CRHR1) and induces disorders of the brain-endocrine-immune network. p53 is activated by hypoxia and involved in tumorigenesis and apoptosis. Whether CRHR1 regulates p53 transactivation to further influence apoptotic genes remains unclear. Here, we showed that hypoxia at a simulated altitude of 5km or 7km for 8 and 24h increased p53 protein and mRNA, and reduced apoptotic bax and IGFBP3 gene expression while upregulating the cell-arrest gene p21 for 8h in rat liver cells. The upregulation of p53 mRNA and downregulation of bax mRNA induced by hypoxia were blocked by pretreatment with the specific CRHR1 antagonist CP-154,526, but the downregulation of IGFBP3 and upregulation of p21 mRNA were not. Furthermore, CRH stimulated p53 mRNA via the ERK 1/2 pathway in the BRL-3A cell line and this was blocked by the ERK 1/2 antagonist U0126. These data provide novel evidence that the CRHR1-triggered ERK 1/2 pathway is involved in the activation of p53 and suppression of the apoptotic bax gene by hypoxia in rat liver.

  10. CRHR1 mediates p53 transcription induced by high altitude hypoxia through ERK 1/2 signaling in rat hepatic cells.

    PubMed

    Zhao, Yang; Wang, Ming-Yang; Hao, Ke; Chen, Xue-Qun; Du, Ji-Zeng

    2013-06-01

    We have previously reported that hypoxia activates corticotrophin-releasing hormone (CRH) and the expression of its type-1 receptor (CRHR1) and induces disorders of the brain-endocrine-immune network. p53 is activated by hypoxia and involved in tumorigenesis and apoptosis. Whether CRHR1 regulates p53 transactivation to further influence apoptotic genes remains unclear. Here, we showed that hypoxia at a simulated altitude of 5km or 7km for 8 and 24h increased p53 protein and mRNA, and reduced apoptotic bax and IGFBP3 gene expression while upregulating the cell-arrest gene p21 for 8h in rat liver cells. The upregulation of p53 mRNA and downregulation of bax mRNA induced by hypoxia were blocked by pretreatment with the specific CRHR1 antagonist CP-154,526, but the downregulation of IGFBP3 and upregulation of p21 mRNA were not. Furthermore, CRH stimulated p53 mRNA via the ERK 1/2 pathway in the BRL-3A cell line and this was blocked by the ERK 1/2 antagonist U0126. These data provide novel evidence that the CRHR1-triggered ERK 1/2 pathway is involved in the activation of p53 and suppression of the apoptotic bax gene by hypoxia in rat liver. PMID:23538210

  11. The influence of altitude hypoxia on uroflowmetry parameters in women.

    PubMed

    Verratti, Vittore; Paulesu, Luana; Pietrangelo, Tiziana; Doria, Christian; Di Giulio, Camillo; Aloisi, Anna Maria

    2016-09-01

    There is scientific evidence to suggest a correlation between hypoxia and the physiology of micturition. During a Himalayan Scientific and Mountaineering Expedition, we performed tests to investigate the functional interactions between altitude hypoxia and uroflowmetry parameters in women. The tests were carried out in seven women (36.3 ± 7.1 yr) from normoxic [1,340 meters above sea level (m a.s.l.)] to hypoxic conditions (up to 5,050 m a.s.l.) and during the return descent. The following measures were determined: uroflowmetry parameters and saturation of peripheral oxygen (SpO2 ). As expected, SpO2 decreased from 97.7 to 77.8% with increasing altitude. Micturition flow time, flow volume, and voiding time increased with altitude (P < 0.04 for all), indicating a negative correlation with SpO2 In conclusion, in young adult women, micturition physiological parameters were affected during adaptation to hypoxia; the correlation with SpO2 strongly suggests a role of hypoxia in these changes. These data could help to support the design of new strategies for both prevention and medical treatment. An example of the latter might be hyperbaric oxygen therapy, which in some studies has proved able to reduce the symptoms in patients with hypoxic bladder. PMID:27358054

  12. The high-altitude brain.

    PubMed

    Hornbein, T F

    2001-09-01

    The highest place on our planet, Mount Everest (8850 m), appears to be close to the limit of how high an acclimatized human can go, albeit slowly. In this paper, I will explore the possibility that what limits human performance at such extreme degrees of hypoxia is the availability of oxygen to the brain. Also, one of the known costs of such extreme exposure is residual mild impairment of performance on neuropsychometric tests after return to sea level, implying injury to brain cells. That such injury could occur in the absence of any overt impairment of function, much less without loss of consciousness, is unexpected. I will speculate about physiological mechanisms that might cause or contribute to both decrements in real-time performance while at altitude and residual deficits for a time after return to low elevations; the effects of hypoxia on brain cells are an even greater puzzle at the present time.

  13. MIBG scintigraphic assessment of cardiac adrenergic activity in response to altitude hypoxia

    SciTech Connect

    Richalet, J.P.; Merlet, P.; Bourguignon, M.; Le-Trong, J.L.; Keromes, A.; Rathat, C.; Jouve, B.; Hot, M.A.; Castaigne, A.; Syrota, A. )

    1990-01-01

    High altitude hypoxia induces a decrease in the cardiac chronotropic function at maximal exercise or in response to isoproterenol infusion, suggesting an alteration in the cardiac sympathetic activation. Iodine-123 metaiodobenzylguanidine (({sup 123}I)MIBG) was used to map scintigraphically the cardiac sympathetic neuronal function in six male subjects (aged 32 {plus minus} 7 yr) after an exposure to high altitude that created hypoxic conditions. Results obtained just after return to sea level (RSL) were compared with the normal values obtained after 2 or 3 mo of normoxia (N). A static image was created as the sum of the 16-EKG gated images recorded for 10 min in the anterior view of the chest at 20, 60, 120, and 240 min after injection. Regions of interest were located over the heart (H), lungs (L), and mediastinum (M) regions. There was a significant decrease in the H/M and the L/M ratios in RSL compared to N condition. Plasma norepinephrine concentration was elevated during the stay at altitude but not significantly different in RSL compared to N. In conclusion, cardiac ({sup 123}I)MIBG uptake is reduced after an exposure to altitude hypoxia, supporting the hypothesis of an hypoxia-induced reduction of adrenergic neurotransmitter reserve in the myocardium. Furthermore, the observed significant decrease in pulmonary MIBG uptake suggests an alteration of endothelial cell function after exposure to chronic hypoxia.

  14. The morbid anatomy of high altitude

    PubMed Central

    Heath, Donald

    1979-01-01

    The morbid anatomical changes which take place in man and animals exposed to the chronic hypoxia of residence at high altitude are briefly reviewed. ImagesFig. 1Fig. 2Fig. 3Fig. 5Fig. 4Fig. 6Fig. 7Fig. 8 PMID:493205

  15. The autonomic nervous system at high altitude

    PubMed Central

    Drinkhill, Mark J.; Rivera-Chira, Maria

    2007-01-01

    The effects of hypobaric hypoxia in visitors depend not only on the actual elevation but also on the rate of ascent. Sympathetic activity increases and there are increases in blood pressure and heart rate. Pulmonary vasoconstriction leads to pulmonary hypertension, particularly during exercise. The sympathetic excitation results from hypoxia, partly through chemoreceptor reflexes and partly through altered baroreceptor function. High pulmonary arterial pressures may also cause reflex systemic vasoconstriction. Most permanent high altitude dwellers show excellent adaptation although there are differences between populations in the extent of the ventilatory drive and the erythropoiesis. Some altitude dwellers, particularly Andeans, may develop chronic mountain sickness, the most prominent characteristic of which being excessive polycythaemia. Excessive hypoxia due to peripheral chemoreceptor dysfunction has been suggested as a cause. The hyperviscous blood leads to pulmonary hypertension, symptoms of cerebral hypoperfusion, and eventually right heart failure and death. PMID:17264976

  16. Developmental functional adaptation to high altitude: review.

    PubMed

    Frisancho, A Roberto

    2013-01-01

    Various approaches have been used to understand the origins of the functional traits that characterize the Andean high-altitude native. Based on the conceptual framework of developmental functional adaptation which postulates that environmental influences during the period of growth and development have long lasting effects that may be expressed during adulthood, we initiated a series of studies addressed at determining the pattern of physical growth and the contribution of growth and development to the attainment of full functional adaptation to high-altitude of low and high altitude natives living under rural and urban conditions. Current research indicate that: (a) the pattern of growth at high altitude due to limited nutritional resources, physical growth in body size is delayed but growth in lung volumes is accelerated because of hypoxic stress); (b) low-altitude male and female urban natives can attain a full functional adaptation to high altitude by exposure to high-altitude hypoxia during the period of growth and development; (c) both experimental studies on animals and comparative human studies indicate that exposure to high altitude during the period of growth and development results in the attainment of a large residual lung volume; (d) this developmentally acquired enlarged residual lung volume and its associated increase in alveolar area when combined with the increased tissue capillarization and moderate increase in red blood cells and hemoglobin concentration contributes to the successful functional adaptation of the Andean high-altitude native to hypoxia; and (e) any specific genetic traits that are related to the successful functional adaptation of Andean high-altitude natives have yet to be identified.

  17. Intermittent hypobaric hypoxia induces altitude acclimation and improves the lactate threshold.

    PubMed

    Casas, M; Casas, H; Pagés, T; Rama, R; Ricart, A; Ventura, J L; Ibáñez, J; Rodríguez, F A; Viscor, G

    2000-02-01

    The physiological responses to short-term intermittent exposure to hypoxia in a hypobaric chamber were evaluated. The exposure to hypoxia was compatible with normal daily activity. The ability of the hypoxia program to induce hematological and ventilatory adaptations leading to altitude acclimation and to improve physical performance capacity was tested. Six members of a high-altitude expedition were exposed to intermittent hypoxia and low-intensity exercise (in cycle-ergometer) in the INEFC-UB hypobaric chamber over 17 d, 3-5 h x d(-1), at simulated altitude of 4,000 m to 5,500 m. Following this hypoxia exposure program, significant increases were found in packed cell volume (41 to 44.6%; p<0.05), red blood cells count (4.607 to 4.968 10(6) cells x microL(-1); p<0.05), and hemoglobin concentration (14.8 to 16.4 g x dL(-1); p<0.05), thus implying an increase in the blood oxygen transport capacity. Significant differences in exercise blood lactate kinetics and heart rate were also observed. The lactate vs. exercise load curve shifted to the right and heart rate decreased, thus indicating an improvement of aerobic endurance. These results were associated with a significant increase in the ventilatory anaerobic threshold (p<0.05). Significant increases (p<0.05) in pulmonary ventilation, tidal volume, respiratory frequency, O2 uptake, CO2 output and ventilatory equivalents to oxygen (VE/Vo2) and carbon dioxide (VE/co2) were observed at the ventilatory threshold and within the transitional zone of the curves. We conclude that short-term intermittent exposure to moderate hypoxia, in combination with low-intensity exercise in a hypobaric chamber, is sufficient to improve aerobic capacity and to induce altitude acclimation.

  18. High Altitude Medical Problems

    PubMed Central

    Hultgren, Herbert N.

    1979-01-01

    Increased travel to high altitude areas by mountaineers and nonclimbing tourists has emphasized the clinical problems associated with rapid ascent. Acute mountain sickness affects most sojourners at elevations above 10,000 feet. Symptoms are usually worse on the second or third day after arrival. Gradual ascent, spending one to three days at an intermediate altitude, and the use of acetazolamide (Diamox) will prevent or ameliorate symptoms in most instances. Serious and potentially fatal problems, such as high altitude pulmonary edema or cerebral edema, occur in approximately 0.5 percent to 1.0 percent of visitors to elevations above 10,000 feet—especially with heavy physical exertion on arrival, such as climbing or skiing. Early recognition, high flow oxygen therapy and prompt descent are crucially important in management. Our knowledge of the causes of these and other high altitude problems, such as retinal hemorrhage, systemic edema and pulmonary hypertension, is still incomplete. Even less is known of the effect of high altitudes on medical conditions common at sea level or on the action of commonly used drugs. ImagesFigure 2. PMID:483805

  19. [High altitude training: sense, nonsense, trends].

    PubMed

    Friedmann, B; Bärtsch, P

    1997-11-01

    Athletes who need high endurance capacity often use training at moderately high altitude (1500-3000 m) to improve oxygen delivery and utilization because of a hypoxia-induced increase of the red blood cell volume and adaptations at the muscular level. As maximal heart rates decrease at high altitude and plasma lactate levels for a given workload change during prolonged exposure to high altitude, it can be difficult to control and adapt the intensity and duration of the work-outs. Furthermore, maximal performance capacity decreases and therefore training intensity at high altitude is usually reduced compared to training at sea level. To avoid these disadvantages at high altitude a concept of living at moderately high altitude and training at lower elevations, termed "live high-train low" evolved, opposing the conventional concept of "live high-train high". A third option using a hypobaric chamber ("live low-train low") is hardly used anymore for training athletes. Studies on the effects of conventional high-altitude training for the improvement of athletic performance often lack a rigorous controlled design and yield controversial results. Regarding the new concept of "live high-train low" there is only one controlled study on college athletes and it shows a minor advantage of this new approach compared to conventional high-altitude training. However, training concepts are especially important for elite competitive athletes, and controlled studies with such individuals are very difficult to perform. Therefore, it appears that today we cannot answer the question of whether altitude-specific physiologic factors or non-altitude-related benefits of training camps account for the success of individual athletes.

  20. [Respiratory system at high altitude: pathophysiology and novel therapy options].

    PubMed

    Trübsbach, Suzan S; Pircher, Iris; Treml, Benedict; Löckinger, Alex; Kleinsasser, Axel T

    2011-02-01

    This mini-review conveys information on lung function in hypoxia. Included are presentations of shape and layering of the atmosphere, physiologic basics of lung function at high altitude, pathophysiology of high altitude pulmonary edema (HAPE) and of current and potential therapy approaches for HAPE. PMID:21318740

  1. Can High Altitude Influence Cytokines and Sleep?

    PubMed Central

    de Aquino Lemos, Valdir; dos Santos, Ronaldo Vagner Thomatieli; Lira, Fabio Santos; Rodrigues, Bruno; Tufik, Sergio; de Mello, Marco Tulio

    2013-01-01

    The number of persons who relocate to regions of high altitude for work, pleasure, sport, or residence increases every year. It is known that the reduced supply of oxygen (O2) induced by acute or chronic increases in altitude stimulates the body to adapt to new metabolic challenges imposed by hypoxia. Sleep can suffer partial fragmentation because of the exposure to high altitudes, and these changes have been described as one of the responsible factors for the many consequences at high altitudes. We conducted a review of the literature during the period from 1987 to 2012. This work explored the relationships among inflammation, hypoxia and sleep in the period of adaptation and examined a novel mechanism that might explain the harmful effects of altitude on sleep, involving increased Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) production from several tissues and cells, such as leukocytes and cells from skeletal muscle and brain. PMID:23690660

  2. Ear - blocked at high altitudes

    MedlinePlus

    ... ears; Flying and blocked ears; Eustachian tube dysfunction - high altitude ... the middle ear and the back of the nose and upper throat. ... down from high altitudes. Chewing gum the entire time you are ...

  3. Sleep at high altitude: guesses and facts.

    PubMed

    Bloch, Konrad E; Buenzli, Jana C; Latshang, Tsogyal D; Ulrich, Silvia

    2015-12-15

    Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0.8-4.6 Hz). Although some studies suggest an increase in arousals from sleep at high altitude, this is not a consistent finding. Whether sleep instability at high altitude is triggered by periodic breathing or vice versa is still uncertain. Overnight changes in slow wave-derived encephalographic measures of neuronal synchronization in healthy subjects were less pronounced at moderately high (2,590 m) compared with low altitude (490 m), and this was associated with a decline in sleep-related memory consolidation. Correspondingly, exacerbation of breathing and sleep disturbances experienced by lowlanders with obstructive sleep apnea during a stay at 2,590 m was associated with poor performance in driving simulator tests. These findings suggest that altitude-related alterations in sleep may adversely affect daytime performance. Despite recent advances in our understanding of sleep at altitude, further research is required to better establish the role of gender and age in alterations of sleep at different altitudes, to determine the influence of acclimatization and of altitude-related illness, and to uncover the characteristics of sleep in highlanders that may serve as a study paradigm of sleep in patients exposed to chronic hypoxia due to cardiorespiratory disease.

  4. Th2 lymphocytes migrating to the bone marrow under high-altitude hypoxia promote erythropoiesis via activin A and interleukin-9.

    PubMed

    Li, Peng; Zheng, Shan-jun; Jiang, Chun-hua; Zhou, Si-min; Tian, Huai-jun; Zhang, Gang; Gao, Yu-qi

    2014-09-01

    The mechanism of accelerated erythropoiesis under the hypoxic conditions of high altitude (HA) remains largely obscure. Here, we investigated the potential role of bone marrow (BM) T cells in the increased production of erythrocytes at HA. We found that mice exposed to a simulated altitude of 6,000 m for 1-3 weeks exhibited a significant expansion of BM CD4+ cells, mainly caused by increasing T helper 2 (Th2) cells. Using a coculture model of BM T cells and hematopoietic stem/progenitor cells, we observed that BM CD4+ cells from hypoxic mice induced erythroid output more easily, in agreement with the erythroid-enhancing effect observed for Th2-condition-cultured BM CD4+ cells. It was further demonstrated that elevated secretion of activin A and interleukin-9 by BM Th2 cells of hypoxic mice promoted erythroid differentiation of hematopoietic stem/progenitor cells and the growth of erythroblasts, respectively. Our study also provided evidence that the CXCL12-CXCR4 interaction played an important role in Th2 cell trafficking to the BM under HA conditions. These results collectively suggest that Th2 cells migrating to the BM during HA exposure have a regulatory role in erythropoiesis, which provides new insight into the mechanism of high altitude polycythemia.

  5. Early history of high-altitude physiology.

    PubMed

    West, John B

    2016-02-01

    High-altitude physiology can be said to have begun in 1644 when Torricelli described the first mercury barometer and wrote the immortal words "We live submerged at the bottom of an ocean of the element air." Interestingly, the notion of atmospheric pressure had eluded his teacher, the great Galileo. Blaise Pascal was responsible for describing the fall in pressure with increasing altitude, and Otto von Guericke gave a dramatic demonstration of the enormous force that could be developed by atmospheric pressure. Robert Boyle learned of Guericke's experiment and, with Robert Hooke, constructed the first air pump that allowed small animals to be exposed to a low pressure. Hooke also constructed a small low-pressure chamber and exposed himself to a simulated altitude of about 2400 meters. With the advent of ballooning, humans were rapidly exposed to very low pressures, sometimes with tragic results. For example, the French balloon, Zénith, rose to over 8000 m, and two of the three aeronauts succumbed to the hypoxia. Paul Bert was the first person to clearly state that the deleterious effects of high altitude were caused by the low partial pressure of oxygen (PO2), and later research was accelerated by high-altitude stations and expeditions to high altitude. PMID:25762218

  6. Early history of high-altitude physiology.

    PubMed

    West, John B

    2016-02-01

    High-altitude physiology can be said to have begun in 1644 when Torricelli described the first mercury barometer and wrote the immortal words "We live submerged at the bottom of an ocean of the element air." Interestingly, the notion of atmospheric pressure had eluded his teacher, the great Galileo. Blaise Pascal was responsible for describing the fall in pressure with increasing altitude, and Otto von Guericke gave a dramatic demonstration of the enormous force that could be developed by atmospheric pressure. Robert Boyle learned of Guericke's experiment and, with Robert Hooke, constructed the first air pump that allowed small animals to be exposed to a low pressure. Hooke also constructed a small low-pressure chamber and exposed himself to a simulated altitude of about 2400 meters. With the advent of ballooning, humans were rapidly exposed to very low pressures, sometimes with tragic results. For example, the French balloon, Zénith, rose to over 8000 m, and two of the three aeronauts succumbed to the hypoxia. Paul Bert was the first person to clearly state that the deleterious effects of high altitude were caused by the low partial pressure of oxygen (PO2), and later research was accelerated by high-altitude stations and expeditions to high altitude.

  7. [Hemoglobin and testosterone: importance on high altitude acclimatization and adaptation].

    PubMed

    Gonzales, Gustavo F

    2011-03-01

    The different types of response mechanisms that the organism uses when exposed to hypoxia include accommodation, acclimatization and adaptation. Accommodation is the initial response to acute exposure to high altitude hypoxia and is characterized by an increase in ventilation and heart rate. Acclimatization is observed in individuals temporarily exposed to high altitude, and to some extent, it enables them to tolerate the high altitudes. In this phase, erythropoiesis is increased, resulting in higher hemoglobin and hematocrit levels to improve oxygen delivery capacity. Adaptation is the process of natural acclimatization where genetical variations and acclimatization play a role in allowing subjects to live without any difficulties at high altitudes. Testosterone is a hormone that regulates erythropoiesis and ventilation and could be associated to the processes of acclimatization and adaptation to high altitude. Excessive erythrocytosis, which leads to chronic mountain sickness, is caused by low arterial oxygen saturation, ventilatory inefficiency and reduced ventilatory response to hypoxia. Testosterone increases during acute exposure to high altitude and also in natives at high altitude with excessive erythrocytosis. Results of current research allow us to conclude that increase in serum testosterone and hemoglobin is adequate for acclimatization, as they improve oxygen transport, but not for high altitude adaptation, since high serum testosterone levels are associated to excessive erythrocytosis.

  8. HIGH LIFE: High altitude fatalities led to pulse oximetry.

    PubMed

    Severinghaus, John W

    2016-01-15

    In 1875, Paul Bert linked high altitude danger to the low partial pressure of oxygen when 2 of 3 French balloonists died euphorically at about 8,600 m altitude. World War I fatal crashes of high altitude fighter pilots led to a century of efforts to use oximetry to warn pilots. The carotid body, discovered in 1932 to be the hypoxia detector, led to most current physiologic understanding of the body's respiratory responses to hypoxia and CO2. The author describes some of his UCSF group's work: In 1963, we reported both the brain's ventral medullary near-surface CO2 (and pH) chemosensors and the role of cerebrospinal fluid in acclimatization to altitude. In 1966, we reported the effect of altitude on cerebral blood flow and later the changes of carotid body sensitivity at altitude and the differences in natives of high altitude. In 1973, pulse oximetry was invented when Japanese biophysicist Takuo Aoyagi read and applied to pulses a largely forgotten 35-year-old discovery by English medical student J. R. Squire of a method of computing oxygen saturation from red and infrared light passing through both perfused and blanched tissue.

  9. High altitude pulmonary edema in mountain climbers.

    PubMed

    Korzeniewski, Krzysztof; Nitsch-Osuch, Aneta; Guzek, Aneta; Juszczak, Dariusz

    2015-04-01

    Every year thousands of ski, trekking or climbing fans travel to the mountains where they stay at the altitude of more than 2500-3000m above sea level or climb mountain peaks, often exceeding 7000-8000m. High mountain climbers are at a serious risk from the effects of adverse environmental conditions prevailing at higher elevations. They may experience health problems resulting from hypotension, hypoxia or exposure to low temperatures; the severity of those conditions is largely dependent on elevation, time of exposure as well as the rate of ascent and descent. A disease which poses a direct threat to the lives of mountain climbers is high altitude pulmonary edema (HAPE). It is a non-cardiogenic pulmonary edema which typically occurs in rapidly climbing unacclimatized lowlanders usually within 2-4 days of ascent above 2500-3000m. It is the most common cause of death resulting from the exposure to high altitude. The risk of HAPE rises with increased altitude and faster ascent. HAPE incidence ranges from an estimated 0.01% to 15.5%. Climbers with a previous history of HAPE, who ascent rapidly above 4500m have a 60% chance of illness recurrence. The aim of this article was to present the relevant details concerning epidemiology, pathophysiology, clinical symptoms, prevention, and treatment of high altitude pulmonary edema among climbers in the mountain environment.

  10. [High-altitude pulmonary edema in Japan].

    PubMed

    Kobayashi, T

    1995-12-01

    To understand the pathophysiology of high-altitude pulmonary edema (HAPE), we examined the pathway of adaptation to high altitude in lifelong of Tibet. The Tibetan natives had higher exercise performance, but lower maximal oxygen uptake and lower blood lactate concentrations than did acclimatized Han newcomers. Clinical and basic studies done to determine the pathophysiologic characteristics of 47 patients with HAPE and of subjects susceptible to HAPE. The altitude of onset was 2,680 m to 3,190 m above sea level. Results of hemodynamic studies and the presence of protein-rich edema fluid indicated that HAPE is noncardiogenic and is a type of increased permeability edema. The levels of IL-1 beta, IL-6, IL-8, and TNF-alpha in bronchoalveolar lavage fluid from subjects with HAPE were high on admission. The subjects susceptible to HAPE had much greater increases in an index of pulmonary vascular resistance than did the controls, which resulted in much higher levels of pulmonary arterial pressure during both acute hypoxia and hypobaria. The subjects susceptible to HAPE also has blunted hypoxic ventilatory drives. We studied whether human leukocyte antigen DR-6 functions as a genetic predisposition to HAPE. The frequency of DR-6 was increased in the subjects susceptible to HAPE, which suggests that they have a constitutional abnormality in the pulmonary circulatory, and ventilatory responses to hypoxia and hypobaria, and that genetic factors may be involved in the development of HAPE.

  11. High altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdo, Renee Anna; Moller, David

    1990-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000 plus feet, which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 feet for six hours at Mach 0.7, while carrying 3,000 lbs. of payload. In addition, the aircraft must have a minimum range of 6,000 miles. In consideration of the novel nature of this project, the pilot must be able to take control in the event of unforeseen difficulties. Three aircraft configurations were determined to be the most suitable - a joined-wing, a biplane, and a twin-boom conventional airplane. The performance of each configuration was analyzed to investigate the feasibility of the project.

  12. Energy metabolism and the high-altitude environment.

    PubMed

    Murray, Andrew J

    2016-01-01

    At high altitude the barometric pressure falls, challenging oxygen delivery to the tissues. Thus, whilst hypoxia is not the only physiological stress encountered at high altitude, low arterial P(O2) is a sustained feature, even after allowing adequate time for acclimatization. Cardiac and skeletal muscle energy metabolism is altered in subjects at, or returning from, high altitude. In the heart, energetic reserve falls, as indicated by lower phosphocreatine-to-ATP ratios. The underlying mechanism is unknown, but in the hypoxic rat heart fatty acid oxidation and respiratory capacity are decreased, whilst pyruvate oxidation is also lower after sustained hypoxic exposure. In skeletal muscle, there is not a consensus. With prolonged exposure to extreme high altitude (>5500 m) a loss of muscle mitochondrial density is seen, but this was not observed in a simulated ascent of Everest in hypobaric chambers. At more moderate high altitude, decreased respiratory capacity may occur without changes in mitochondrial volume density, and fat oxidation may be downregulated, although this is not seen in all studies. The underlying mechanisms, including the possible role of hypoxia-signalling pathways, remain to be resolved, particularly in light of confounding factors in the high-altitude environment. In high-altitude-adapted Tibetan natives, however, there is evidence of natural selection centred around the hypoxia-inducible factor pathway, and metabolic features in this population (e.g. low cardiac phosphocreatine-to-ATP ratios, increased cardiac glucose uptake and lower muscle mitochondrial densities) share similarities with those in acclimatized lowlanders, supporting a possible role for the hypoxia-inducible factor pathway in the metabolic response of cardiac and skeletal muscle energy metabolism to high altitude. PMID:26315373

  13. Energy metabolism and the high-altitude environment.

    PubMed

    Murray, Andrew J

    2016-01-01

    At high altitude the barometric pressure falls, challenging oxygen delivery to the tissues. Thus, whilst hypoxia is not the only physiological stress encountered at high altitude, low arterial P(O2) is a sustained feature, even after allowing adequate time for acclimatization. Cardiac and skeletal muscle energy metabolism is altered in subjects at, or returning from, high altitude. In the heart, energetic reserve falls, as indicated by lower phosphocreatine-to-ATP ratios. The underlying mechanism is unknown, but in the hypoxic rat heart fatty acid oxidation and respiratory capacity are decreased, whilst pyruvate oxidation is also lower after sustained hypoxic exposure. In skeletal muscle, there is not a consensus. With prolonged exposure to extreme high altitude (>5500 m) a loss of muscle mitochondrial density is seen, but this was not observed in a simulated ascent of Everest in hypobaric chambers. At more moderate high altitude, decreased respiratory capacity may occur without changes in mitochondrial volume density, and fat oxidation may be downregulated, although this is not seen in all studies. The underlying mechanisms, including the possible role of hypoxia-signalling pathways, remain to be resolved, particularly in light of confounding factors in the high-altitude environment. In high-altitude-adapted Tibetan natives, however, there is evidence of natural selection centred around the hypoxia-inducible factor pathway, and metabolic features in this population (e.g. low cardiac phosphocreatine-to-ATP ratios, increased cardiac glucose uptake and lower muscle mitochondrial densities) share similarities with those in acclimatized lowlanders, supporting a possible role for the hypoxia-inducible factor pathway in the metabolic response of cardiac and skeletal muscle energy metabolism to high altitude.

  14. Insulin secretion at high altitude in man

    NASA Astrophysics Data System (ADS)

    Sawhney, R. C.; Malhotra, A. S.; Singh, T.; Rai, R. M.; Sinha, K. C.

    1986-09-01

    The effect of hypoxia on circulatory levels of insulin, its response to oral glucose administration (100 g) and changes in circadian rhythms of glucose as well as insulin were evaluated in euglycemic males at sea level (SL, 220 m) during their stay at high altitude (3500 m, SJ) and in high altitude natives (HAN). Basal glucose levels were not altered at high altitude but the rise in glucose (δ glucose) after glucose load was significantly higher in SJ and HAN (p<0.01) as compared to SL values. An increase (p<0.01) both in basal as well as glucose induced rise in insulin secretion (δ insulin) was observed at HA. The rise in insulin in SJ was significantly higher (p<0.01) than in HAN. This elevation in glucose and insulin levels was also evident at different times of the day. The circadian rhythmicity of glucose as well as insulin was altered by the altitude stress. The findings of the study show a rise in insulin level at HA but the hyperglycemia in the face of hyper-insulinism require the presumption of a simultaneous and dispropotionate rise of insulin antagonistic hormones upsetting the effect of insulin on glucose metabolism.

  15. Increased Intraregional Synchronized Neural Activity in Adult Brain After Prolonged Adaptation to High-Altitude Hypoxia: A Resting-State fMRI Study.

    PubMed

    Chen, Ji; Fan, Cunxiu; Li, Jinqiang; Han, Qiaoqing; Lin, Jianzhong; Yang, Tianhe; Zhang, Jiaxing

    2016-03-01

    The human brain is intrinsically plastic such that its functional architecture can be reorganized in response to environmental pressures and physiological changes. However, it remains unclear whether a compensatory modification of spontaneous neural activity occurs in adult brain during prolonged high-altitude (HA) adaptation. In this study, we obtained resting-state functional magnetic resonance (MR) images in 16 adults who have immigrated to Qinghai-Tibet Plateau (2300-4400 m) for 2 years and in 16 age-matched sea level (SL) controls. A validated regional homogeneity (Reho) method was employed to investigate the local synchronization of resting-state functional magnetic resonance imaging (fMRI) signals. Seed connectivity analysis was carried out subsequently. Cognitive and physiological assessments were made and correlated with the image metrics. Compared with SL controls, global mean Reho was significantly increased in HA immigrants as well as a regional increase in the right inferolateral sensorimotor cortex. Furthermore, mean z-Reho value extracted within the inferolateral sensorimotor area showed trend-level significant inverse correlation with memory search reaction time in HA immigrants. These observations, for the first time, provide evidence of adult brain resilience of spontaneous neural activity after long-term HA exposure without inherited and developmental effects. Resting-state fMRI could yield valuable information for central mechanisms underlying respiratory and cognitive compensations in adults during prolonged environmentally hypoxic adaptation, paving the way for future HA-adaptive training.

  16. High-Altitude Illnesses: Physiology, Risk Factors, Prevention, and Treatment

    PubMed Central

    Taylor, Andrew T.

    2011-01-01

    High-altitude illnesses encompass the pulmonary and cerebral syndromes that occur in non-acclimatized individuals after rapid ascent to high altitude. The most common syndrome is acute mountain sickness (AMS) which usually begins within a few hours of ascent and typically consists of headache variably accompanied by loss of appetite, nausea, vomiting, disturbed sleep, fatigue, and dizziness. With millions of travelers journeying to high altitudes every year and sleeping above 2,500 m, acute mountain sickness is a wide-spread clinical condition. Risk factors include home elevation, maximum altitude, sleeping altitude, rate of ascent, latitude, age, gender, physical condition, intensity of exercise, pre-acclimatization, genetic make-up, and pre-existing diseases. At higher altitudes, sleep disturbances may become more profound, mental performance is impaired, and weight loss may occur. If ascent is rapid, acetazolamide can reduce the risk of developing AMS, although a number of high-altitude travelers taking acetazolamide will still develop symptoms. Ibuprofen can be effective for headache. Symptoms can be rapidly relieved by descent, and descent is mandatory, if at all possible, for the management of the potentially fatal syndromes of high-altitude pulmonary and cerebral edema. The purpose of this review is to combine a discussion of specific risk factors, prevention, and treatment options with a summary of the basic physiologic responses to the hypoxia of altitude to provide a context for managing high-altitude illnesses and advising the non-acclimatized high-altitude traveler. PMID:23908794

  17. Genetically based low oxygen affinities of felid hemoglobins: lack of biochemical adaptation to high-altitude hypoxia in the snow leopard.

    PubMed

    Janecka, Jan E; Nielsen, Simone S E; Andersen, Sidsel D; Hoffmann, Federico G; Weber, Roy E; Anderson, Trevor; Storz, Jay F; Fago, Angela

    2015-08-01

    Genetically based modifications of hemoglobin (Hb) function that increase blood-O2 affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O2 affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood-O2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, we characterized structural and functional variation of big cat Hbs and investigated molecular mechanisms of Hb adaptation and allosteric regulation that may contribute to the extreme hypoxia tolerance of the snow leopard. Experiments revealed that purified Hbs from snow leopard and African lion exhibited equally low O2 affinities and DPG sensitivities. Both properties are primarily attributable to a single amino acid substitution, β2His→Phe, which occurred in the common ancestor of Felidae. Given the low O2 affinity and reduced regulatory capacity of feline Hbs, the extreme hypoxia tolerance of snow leopards must be attributable to compensatory modifications of other steps in the O2-transport pathway.

  18. Genetically based low oxygen affinities of felid hemoglobins: lack of biochemical adaptation to high-altitude hypoxia in the snow leopard

    PubMed Central

    Janecka, Jan E.; Nielsen, Simone S. E.; Andersen, Sidsel D.; Hoffmann, Federico G.; Weber, Roy E.; Anderson, Trevor; Storz, Jay F.; Fago, Angela

    2015-01-01

    ABSTRACT Genetically based modifications of hemoglobin (Hb) function that increase blood–O2 affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O2 affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood–O2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, we characterized structural and functional variation of big cat Hbs and investigated molecular mechanisms of Hb adaptation and allosteric regulation that may contribute to the extreme hypoxia tolerance of the snow leopard. Experiments revealed that purified Hbs from snow leopard and African lion exhibited equally low O2 affinities and DPG sensitivities. Both properties are primarily attributable to a single amino acid substitution, β2His→Phe, which occurred in the common ancestor of Felidae. Given the low O2 affinity and reduced regulatory capacity of feline Hbs, the extreme hypoxia tolerance of snow leopards must be attributable to compensatory modifications of other steps in the O2-transport pathway. PMID:26246610

  19. Genetically based low oxygen affinities of felid hemoglobins: lack of biochemical adaptation to high-altitude hypoxia in the snow leopard.

    PubMed

    Janecka, Jan E; Nielsen, Simone S E; Andersen, Sidsel D; Hoffmann, Federico G; Weber, Roy E; Anderson, Trevor; Storz, Jay F; Fago, Angela

    2015-08-01

    Genetically based modifications of hemoglobin (Hb) function that increase blood-O2 affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O2 affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood-O2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, we characterized structural and functional variation of big cat Hbs and investigated molecular mechanisms of Hb adaptation and allosteric regulation that may contribute to the extreme hypoxia tolerance of the snow leopard. Experiments revealed that purified Hbs from snow leopard and African lion exhibited equally low O2 affinities and DPG sensitivities. Both properties are primarily attributable to a single amino acid substitution, β2His→Phe, which occurred in the common ancestor of Felidae. Given the low O2 affinity and reduced regulatory capacity of feline Hbs, the extreme hypoxia tolerance of snow leopards must be attributable to compensatory modifications of other steps in the O2-transport pathway. PMID:26246610

  20. A genetic mechanism for Tibetan high-altitude adaptation

    PubMed Central

    Lorenzo, Felipe R; Huff, Chad; Myllymäki, Mikko; Olenchock, Benjamin; Swierczek, Sabina; Tashi, Tsewang; Gordeuk, Victor; Wuren, Tana; Ri-Li, Ge; McClain, Donald A; Khan, Tahsin M; Koul, Parvaiz A; Guchhait, Prasenjit; Salama, Mohamed E; Xing, Jinchuan; Semenza, Gregg L; Liberzon, Ella; Wilson, Andrew; Simonson, Tatum S; Jorde, Lynn B; Kaelin, William G; Koivunen, Peppi; Prchal, Josef T

    2015-01-01

    Tibetans do not exhibit increased hemoglobin concentration at high altitude. We describe a high-frequency missense mutation in the EGLN1 gene, which encodes prolyl hydroxylase 2 (PHD2), that contributes to this adaptive response. We show that a variant in EGLN1, c.[12C>G; 380G>C], contributes functionally to the Tibetan high-altitude phenotype. PHD2 triggers the degradation of hypoxia-inducible factors (HIFs), which mediate many physiological responses to hypoxia, including erythropoiesis. The PHD2 p.[Asp4Glu; Cys127Ser] variant exhibits a lower Km value for oxygen, suggesting that it promotes increased HIF degradation under hypoxic conditions. Whereas hypoxia stimulates the proliferation of wild-type erythroid progenitors, the proliferation of progenitors with the c.[12C>G; 380G>C] mutation in EGLN1 is significantly impaired under hypoxic culture conditions. We show that the c.[12C>G; 380G>C] mutation originated ~8,000 years ago on the same haplotype previously associated with adaptation to high altitude. The c.[12C>G; 380G>C] mutation abrogates hypoxia-induced and HIF-mediated augmentation of erythropoiesis, which provides a molecular mechanism for the observed protection of Tibetans from polycythemia at high altitude. PMID:25129147

  1. Adaptation of iron requirement to hypoxic conditions at high altitude.

    PubMed

    Gassmann, Max; Muckenthaler, Martina U

    2015-12-15

    Adequate acclimatization time to enable adjustment to hypoxic conditions is one of the most important aspects for mountaineers ascending to high altitude. Accordingly, most reviews emphasize mechanisms that cope with reduced oxygen supply. However, during sojourns to high altitude adjustment to elevated iron demand is equally critical. Thus in this review we focus on the interaction between oxygen and iron homeostasis. We review the role of iron 1) in the oxygen sensing process and erythropoietin (Epo) synthesis, 2) in gene expression control mediated by the hypoxia-inducible factor-2 (HIF-2), and 3) as an oxygen carrier in hemoglobin, myoglobin, and cytochromes. The blood hormone Epo that is abundantly expressed by the kidney under hypoxic conditions stimulates erythropoiesis in the bone marrow, a process requiring high iron levels. To ensure that sufficient iron is provided, Epo-controlled erythroferrone that is expressed in erythroid precursor cells acts in the liver to reduce expression of the iron hormone hepcidin. Consequently, suppression of hepcidin allows for elevated iron release from storage organs and enhanced absorption of dietary iron by enterocytes. As recently observed in sojourners at high altitude, however, iron uptake may be hampered by reduced appetite and gastrointestinal bleeding. Reduced iron availability, as observed in a hypoxic mountaineer, enhances hypoxia-induced pulmonary hypertension and may contribute to other hypoxia-related diseases. Overall, adequate systemic iron availability is an important prerequisite to adjust to high-altitude hypoxia and may have additional implications for disease-related hypoxic conditions.

  2. Elevated Suicide Rates at High Altitude: Sociodemographic and Health Issues May Be to Blame

    ERIC Educational Resources Information Center

    Betz, Marian E.; Valley, Morgan A.; Lowenstein, Steven R.; Hedegaard, Holly; Thomas, Deborah; Stallones, Lorann; Honigman, Benjamin

    2011-01-01

    Suicide rates are higher at high altitudes; some hypothesize that hypoxia is the cause. We examined 8,871 suicides recorded in 2006 in 15 states by the National Violent Death Reporting System, with the victim's home county altitude determined from the National Elevation Dataset through FIPS code matching. We grouped cases by altitude (low less…

  3. Increased oxidative stress following acute and chronic high altitude exposure.

    PubMed

    Jefferson, J Ashley; Simoni, Jan; Escudero, Elizabeth; Hurtado, Maria-Elena; Swenson, Erik R; Wesson, Donald E; Schreiner, George F; Schoene, Robert B; Johnson, Richard J; Hurtado, Abdias

    2004-01-01

    The generation of reactive oxygen species is typically associated with hyperoxia and ischemia reperfusion. Recent evidence has suggested that increased oxidative stress may occur with hypoxia. We hypothesized that oxidative stress would be increased in subjects exposed to high altitude hypoxia. We studied 28 control subjects living in Lima, Peru (sea level), at baseline and following 48 h exposure to high altitude (4300 m). To assess the effects of chronic altitude exposure, we studied 25 adult males resident in Cerro de Pasco, Peru (altitude 4300 m). We also studied 27 subjects living in Cerro de Pasco who develop excessive erythrocytosis (hematocrit > 65%) and chronic mountain sickness. Acute high altitude exposure led to increased urinary F(2)-isoprostane, 8-iso PGF(2 alpha) (1.31 +/- 0.8 microg/g creatinine versus 2.15 +/- 1.1, p = 0.001) and plasma total glutathione (1.29 +/- 0.10 micromol versus 1.37 +/- 0.09, p = 0.002), with a trend to increased plasma thiobarbituric acid reactive substance (TBARS) (59.7 +/- 36 pmol/mg protein versus 63.8 +/- 27, p = NS). High altitude residents had significantly elevated levels of urinary 8-iso PGF(2 alpha) (1.3 +/- 0.8 microg/g creatinine versus 4.1 +/- 3.4, p = 0.007), plasma TBARS (59.7 +/- 36 pmol/mg protein versus 85 +/- 28, p = 0.008), and plasma total glutathione (1.29 +/- 0.10 micromol versus 1.55 +/- 0.19, p < 0.0001) compared to sea level. High altitude residents with excessive erythrocytosis had higher levels of oxidative stress compared to high altitude residents with normal hematological adaptation. In conclusion, oxidative stress is increased following both acute exposure to high altitude without exercise and with chronic residence at high altitude.

  4. Central Sleep Apnea at High Altitude.

    PubMed

    Burgess, Keith R; Ainslie, Philip N

    2016-01-01

    The discovery of central sleep apnea (CSA) at high altitude is usually attributed to Angelo Mosso who published in 1898. It can occur in susceptible individuals at altitude above 2000 m, but at very high altitude, say above 5000 m, it will occur in most subjects. Severity is correlated with ventilatory responsiveness, particularly to hypoxia. Theoretically, it should spontaneously improve with time and acclimatization. Although the time course of resolution is not well described, it appears to persist for more than a month at 5000 m.It occurs due to the interaction of hypocapnia with stages 1 and 2 NREM sleep, in the presence of increased loop-gain. The hypocapnia is secondary to hypoxic ventilatory drive. With acclimatization, one might expect that the increase in PaO2 and cerebral blood flow (CBF) would mitigate the CSA. However, over time, both the hypoxic and hypercapnic ventilatory responses increase, causing an increase in loop gain which is a counteracting force.The severity of the CSA can be reduced by descent, supplemental oxygen therapy, oral or intravenous acetazolamide. Recent studies suggest that acute further increases in cerebral blood flow will substantially, but temporarily, reduce central sleep apnea, without altering acid based balance. Very recently, bi-level noninvasive ventilation has also been shown to help (mechanism unknown). Sleep quality can be improved independent of the presence of CSA by the use of benzodiazepine sedation. PMID:27343103

  5. Preparation for football competition at moderate to high altitude.

    PubMed

    Gore, C J; McSharry, P E; Hewitt, A J; Saunders, P U

    2008-08-01

    Analysis of approximately 100 years of home-and-away South American World Cup matches illustrate that football competition at moderate/high altitude (>2000 m) favors the home team, although this is more than compensated by the likelihood of sea-level teams winning at home against the same opponents who have descended from altitude. Nevertheless, the home team advantage at altitudes above approximately 2000 m may reflect that traditionally, teams from sea level or low altitude have not spent 1-2 weeks acclimatizing at altitude. Despite large differences between individuals, in the first few days at high altitude (e.g. La Paz, 3600 m) some players experience symptoms of acute mountain sickness (AMS) such as headache and disrupted sleep, and their maximum aerobic power (VO2max) is approximately 25% reduced while their ventilation, heart rate and blood lactate during submaximal exercise are elevated. Simulated altitude for a few weeks before competition at altitude can be used to attain partial ventilatory acclimation and ameliorated symptoms of AMS. The variety of simulated altitude exposures usually created with enriched nitrogen mixtures of air include resting or exercising for a few hours per day or sleeping approximately 8 h/night in hypoxia. Preparation for competition at moderate/high altitude by training at altitude is probably superior to simulated exposure; however, the optimal duration at moderate/high altitude is unclear. Preparing for 1-2 weeks at moderate/high altitude is a reasonable compromise between the benefits associated with overcoming AMS and partial restoration of VO2max vs the likelihood of detraining.

  6. Oxidative stress and antioxidant status in a lizard Phrynocephalus vlangalii at different altitudes or acclimated to hypoxia.

    PubMed

    Zhang, Yang; Liang, Shiwei; He, Jianzheng; Bai, Yucheng; Niu, Yonggang; Tang, Xiaolong; Li, Dongqin; Chen, Qiang

    2015-12-01

    Oxidative stress is a major challenge for the survival of animals living on plateaus; however, lifelong exposure to high altitudes could generate certain adaptabilities which make them more tolerant to these environments. The aim of the present study was to compare the oxidative stress and antioxidant status between low altitude (LA, 2900m) and high altitude (HA, 4200m) populations of Phrynocephalus vlangalii. The results showed that malondialdehyde levels in the HA populations decreased significantly in the brain, but markedly increased in the muscle and had no significant difference in the liver compared to LA populations. The activity of catalase in the brain was much higher in HA than LA. Except for total antioxidant capacity and glutathione reductase, other antioxidants were similar between the two populations in livers. By contrast, the levels of most antioxidants in muscle decreased markedly with elevation. We also explored the effects of hypoxia on oxidative damage and antioxidant defenses in P. vlangalii. The lizards were acclimated in a simulated hypoxic chamber (15% O2 and 8% O2) for 6weeks. The results showed that in the 8% O2 group, the levels of malondialdehyde, catalase, glutathione and total antioxidant capacity in the brain, and malondialdehyde, catalase and superoxide dismutase in the liver were significantly higher than the 15% O2 group. These findings indicate that in this species the oxidative stress and antioxidant capacity are subject to altitude and hypoxia and this lizard may have acquired some ability to deal with the oxidative stress. PMID:26310105

  7. High altitude atmospheric modeling

    NASA Technical Reports Server (NTRS)

    Hedin, Alan E.

    1988-01-01

    Five empirical models were compared with 13 data sets, including both atmospheric drag-based data and mass spectrometer data. The most recently published model, MSIS-86, was found to be the best model overall with an accuracy around 15 percent. The excellent overall agreement of the mass spectrometer-based MSIS models with the drag data, including both the older data from orbital decay and the newer accelerometer data, suggests that the absolute calibration of the (ensemble of) mass spectrometers and the assumed drag coefficient in the atomic oxygen regime are consistent to 5 percent. This study illustrates a number of reasons for the current accuracy limit such as calibration accuracy and unmodeled trends. Nevertheless, the largest variations in total density in the thermosphere are accounted for, to a very high degree, by existing models. The greatest potential for improvements is in areas where we still have insufficient data (like the lower thermosphere or exosphere), where there are disagreements in technique (such as the exosphere) which can be resolved, or wherever generally more accurate measurements become available.

  8. 'Ome' on the range: update on high-altitude acclimatization/adaptation and disease.

    PubMed

    Luo, Yongjun; Wang, Yuxiao; Lu, Hongxiang; Gao, Yuqi

    2014-11-01

    The main physiological challenge in high-altitude plateau environments is hypoxia. When people living in a plain environment migrate to the plateau, they face the threat of hypoxia. Most people can acclimatize to high altitudes; the acclimatization process mainly consists of short-term hyperventilation and long-term compensation by increased oxygen uptake, transport, and use due to increased red blood cell mass, myoglobin, and mitochondria. If individuals cannot acclimatize to high altitude, they may suffer from a high-altitude disease, such as acute mountain disease (AMS), high-altitude pulmonary edema (HAPE), high-altitude cerebral edema (HACE) or chronic mountain sickness (CMS). Because some individuals are more susceptible to high altitude diseases than others, the incidence of these high-altitude diseases is variable and cannot be predicted. Studying "omes" using genomics, proteomics, metabolomics, transcriptomics, lipidomics, immunomics, glycomics and RNomics can help us understand the factors that mediate susceptibility to high altitude illnesses. Moreover, analysis of the "omes" using a systems biology approach may provide a greater understanding of high-altitude illness pathogenesis and improve the efficiency of the diagnosis and treatment of high-altitude illnesses in the future. Below, we summarize the current literature regarding the role of "omes" in high-altitude acclimatization/adaptation and disease and discuss key research gaps to better understand the contribution of "omes" to high-altitude illness susceptibility.

  9. Lungs at high-altitude: genomic insights into hypoxic responses.

    PubMed

    Mishra, Aastha; Mohammad, Ghulam; Norboo, Tsering; Newman, John H; Pasha, M A Qadar

    2015-07-01

    Hypobaric hypoxia at high altitude (HA) results in reduced blood arterial oxygen saturation, perfusion of organs with hypoxemic blood, and direct hypoxia of lung tissues. The pulmonary complications in the cells of the pulmonary arterioles due to hypobaric hypoxia are the basis of the pathophysiological mechanisms of high-altitude pulmonary edema (HAPE). Some populations that have dwelled at HA for thousands of years have evolutionarily adapted to this environmental stress; unadapted populations may react with excessive physiological responses that impair health. Individual variations in response to hypoxia and the mechanisms of HA adaptation provide insight into physiological responses. Adaptive and maladaptive responses include alterations in pathways such as oxygen sensing, hypoxia signaling, K(+)- and Ca(2+)-gated channels, redox balance, and the renin-angiotensin-aldosterone system. Physiological imbalances are linked with genetic susceptibilities, and nonhomeostatic responses in gene regulation that occur by small RNAs, histone modification, and DNA methylation predispose susceptible humans to these HA illnesses. Elucidation of the interaction of these factors will lead to a more comprehensive understanding of HA adaptations and maladaptations and will lead to new therapeutics for HA disorders related to hypoxic lungs.

  10. Physiological characteristics of elite high-altitude climbers.

    PubMed

    Puthon, L; Bouzat, P; Rupp, T; Robach, P; Favre-Juvin, A; Verges, S

    2016-09-01

    Factors underlying the amplitude of exercise performance reduction at altitude and the development of high-altitude illnesses are not completely understood. To better describe these mechanisms, we assessed cardiorespiratory and tissue oxygenation responses to hypoxia in elite high-altitude climbers. Eleven high-altitude climbers were matched with 11 non-climber trained controls according to gender, age, and fitness level (maximal oxygen consumption, VO2 max ). Subjects performed two maximal incremental cycling tests, in normoxia and in hypoxia (inspiratory oxygen fraction: 0.12). Cardiorespiratory measurements and tissue (cerebral and muscle) oxygenation were assessed continuously. Hypoxic ventilatory and cardiac responses were determined at rest and during exercise; hypercapnic ventilatory response was determined at rest. In hypoxia, climbers exhibited similar reductions to controls in VO2 max (climbers -39 ± 7% vs controls -39 ± 9%), maximal power output (-27 ± 5% vs -26 ± 4%), and arterial oxygen saturation (SpO2 ). However, climbers had lower hypoxic ventilatory response during exercise (1.7 ± 0.5 vs 2.6 ± 0.7 L/min/%; P < 0.05) and lower hypercapnic ventilatory response (1.8 ± 1.4 vs 3.8 ± 2.5 mL/min/mmHg; P < 0.05). Finally, climbers exhibited slower breathing frequency, larger tidal volume and larger muscle oxygenation index. These results suggest that elite climbers show some specific ventilatory and muscular responses to hypoxia possibly because of genetic factors or adaptation to frequent high-altitude climbing.

  11. Can patients with coronary heart disease go to high altitude?

    PubMed

    Dehnert, Christoph; Bärtsch, Peter

    2010-01-01

    Tourism to high altitude is very popular and includes elderly people with both manifest and subclinical coronary heart disease (CHD). Thus, risk assessment regarding high altitude exposure of patients with CHD is of increasing interest, and individual recommendations are expected despite the lack of sufficient scientific evidence. The major factor increasing cardiac stress is hypoxia. At rest and for a given external workload, myocardial oxygen demand is increased at altitude, particularly in nonacclimatized individuals, and there is some evidence that blood-flow reserve is reduced in atherosclerotic coronary arteries even in the absence of severe stenosis. Despite a possible imbalance between oxygen demand and oxygen delivery, studies on selected patients have shown that exposure and exercise at altitudes of 3000 to 3500 m is generally safe for patients with stable CHD and sufficient work capacity. During the first days at altitude, patients with stable angina may develop symptoms of myocardial ischemia at slightly lower heart rate x  blood-pressure products. Adverse cardiac events, however, such as unstable angina coronary syndromes, do not occur more frequently compared with sea level except for those who are unaccustomed to exercise. Therefore, training should start before going to altitude, and the altitude-related decrease in exercise capacity should be considered. Travel to 3500 m should be avoided unless patients have stable disease, preserved left ventricular function without residual capacity, and above-normal exercise capacity. CHD patients should avoid travel to elevations above 4500 m owing to severe hypoxia at these altitudes. The risk assessment of CHD patients at altitude should always consider a possible absence of medical support and that cardiovascular events may turn into disaster. PMID:20919884

  12. Pulmonary vascular disease in a rabbit a high altitude

    NASA Astrophysics Data System (ADS)

    Heath, Donald; Williams, David; Rios-Datenz, Jaime; Gosney, John

    1990-03-01

    A male weanling rabbit of the New Zealand White strain, born and living at an altitude of 3800 m in La Paz, Bolivia, developed right ventricular hypertrophy. This was found to be associated with growth of vascular smooth muscle cells in the intima of pulmonary arterioles, and contrasted with muscularization of the walls of pulmonary arterioles, without extension into the intima, found in a healthy, high-altitude control rabbit of the same strain. A low-altitude control showed no such muscularization. It is concluded that alveolar hypoxia, acting directly or through an intermediate agent, is a growth factor for vascular smooth muscle cells in pulmonary arterioles. This is the first report of pulmonary vascular disease due to high altitude in rabbits.

  13. Control of breathing and the circulation in high-altitude mammals and birds.

    PubMed

    Ivy, Catherine M; Scott, Graham R

    2015-08-01

    Hypoxia is an unremitting stressor at high altitudes that places a premium on oxygen transport by the respiratory and cardiovascular systems. Phenotypic plasticity and genotypic adaptation at various steps in the O2 cascade could help offset the effects of hypoxia on cellular O2 supply in high-altitude natives. In this review, we will discuss the unique mechanisms by which ventilation, cardiac output, and blood flow are controlled in high-altitude mammals and birds. Acclimatization to high altitudes leads to some changes in respiratory and cardiovascular control that increase O2 transport in hypoxia (e.g., ventilatory acclimatization to hypoxia). However, acclimatization or development in hypoxia can also modify cardiorespiratory control in ways that are maladaptive for O2 transport. Hypoxia responses that arose as short-term solutions to O2 deprivation (e.g., peripheral vasoconstriction) or regional variation in O2 levels in the lungs (i.e., hypoxic pulmonary vasoconstriction) are detrimental at in chronic high-altitude hypoxia. Evolved changes in cardiorespiratory control have arisen in many high-altitude taxa, including increases in effective ventilation, attenuation of hypoxic pulmonary vasoconstriction, and changes in catecholamine sensitivity of the heart and systemic vasculature. Parallel evolution of some of these changes in independent highland lineages supports their adaptive significance. Much less is known about the genomic bases and potential interactive effects of adaptation, acclimatization, developmental plasticity, and trans-generational epigenetic transfer on cardiorespiratory control. Future work to understand these various influences on breathing and circulation in high-altitude natives will help elucidate how complex physiological systems can be pushed to their limits to maintain cellular function in hypoxia.

  14. Population variation revealed high-altitude adaptation of Tibetan mastiffs.

    PubMed

    Li, Yan; Wu, Dong-Dong; Boyko, Adam R; Wang, Guo-Dong; Wu, Shi-Fang; Irwin, David M; Zhang, Ya-Ping

    2014-05-01

    With the assistance of their human companions, dogs have dispersed into new environments during the expansion of human civilization. Tibetan Mastiff (TM), a native of the Tibetan Plateau, was derived from the domesticated Chinese native dog and, like Tibetans, has adapted to the extreme environment of high altitude. Here, we genotyped genome-wide single-nucleotide polymorphisms (SNPs) from 32 TMs and compared them with SNPs from 20 Chinese native dogs and 14 gray wolves (Canis lupus). We identified 16 genes with signals of positive selection in the TM, with 12 of these candidate genes associated with functions that have roles in adaptation to high-altitude adaptation, such as EPAS1, SIRT7, PLXNA4, and MAFG that have roles in responses to hypoxia. This study provides important information on the genetic diversity of the TM and potential mechanisms for adaptation to hypoxia.

  15. Population variation revealed high-altitude adaptation of Tibetan mastiffs.

    PubMed

    Li, Yan; Wu, Dong-Dong; Boyko, Adam R; Wang, Guo-Dong; Wu, Shi-Fang; Irwin, David M; Zhang, Ya-Ping

    2014-05-01

    With the assistance of their human companions, dogs have dispersed into new environments during the expansion of human civilization. Tibetan Mastiff (TM), a native of the Tibetan Plateau, was derived from the domesticated Chinese native dog and, like Tibetans, has adapted to the extreme environment of high altitude. Here, we genotyped genome-wide single-nucleotide polymorphisms (SNPs) from 32 TMs and compared them with SNPs from 20 Chinese native dogs and 14 gray wolves (Canis lupus). We identified 16 genes with signals of positive selection in the TM, with 12 of these candidate genes associated with functions that have roles in adaptation to high-altitude adaptation, such as EPAS1, SIRT7, PLXNA4, and MAFG that have roles in responses to hypoxia. This study provides important information on the genetic diversity of the TM and potential mechanisms for adaptation to hypoxia. PMID:24520091

  16. High altitude, a natural research laboratory for the study of cardiovascular physiology and pathophysiology.

    PubMed

    Scherrer, Urs; Allemann, Yves; Jayet, Pierre-Yves; Rexhaj, Emrush; Sartori, Claudio

    2010-01-01

    High altitude constitutes an exciting natural laboratory for medical research. Although initially, the aim of high-altitude research was to understand the adaption of the organism to hypoxia and find treatments for altitude-related diseases, during the past decade or so, the scope of this research has broadened considerably. Two important observations led the foundation for the broadening of the scientific scope of high-altitude research. First, high-altitude pulmonary edema represents a unique model that allows studying fundamental mechanisms of pulmonary hypertension and lung edema in humans. Second, the ambient hypoxia associated with high-altitude exposure facilitates the detection of pulmonary and systemic vascular dysfunction at an early stage. Here, we will review studies that, by capitalizing on these observations, have led to the description of novel mechanisms underpinning lung edema and pulmonary hypertension and to the first direct demonstration of fetal programming of vascular dysfunction in humans. PMID:20417338

  17. High altitude, a natural research laboratory for the study of cardiovascular physiology and pathophysiology.

    PubMed

    Scherrer, Urs; Allemann, Yves; Jayet, Pierre-Yves; Rexhaj, Emrush; Sartori, Claudio

    2010-01-01

    High altitude constitutes an exciting natural laboratory for medical research. Although initially, the aim of high-altitude research was to understand the adaption of the organism to hypoxia and find treatments for altitude-related diseases, during the past decade or so, the scope of this research has broadened considerably. Two important observations led the foundation for the broadening of the scientific scope of high-altitude research. First, high-altitude pulmonary edema represents a unique model that allows studying fundamental mechanisms of pulmonary hypertension and lung edema in humans. Second, the ambient hypoxia associated with high-altitude exposure facilitates the detection of pulmonary and systemic vascular dysfunction at an early stage. Here, we will review studies that, by capitalizing on these observations, have led to the description of novel mechanisms underpinning lung edema and pulmonary hypertension and to the first direct demonstration of fetal programming of vascular dysfunction in humans.

  18. High Altitude Ozone Research Balloon

    NASA Technical Reports Server (NTRS)

    Cauthen, Timothy A.; Daniel, Leslie A.; Herrick, Sally C.; Rock, Stacey G.; Varias, Michael A.

    1990-01-01

    In order to create a mission model of the high altitude ozone research balloon (HAORB) several options for flight preparation, altitude control, flight termination, and payload recovery were considered. After the optimal launch date and location for two separate HAORB flights were calculated, a method for reducing the heat transfer from solar and infrared radiation was designed and analytically tested. This provided the most important advantage of the HAORB over conventional balloons, i.e., its improved flight duration. Comparisons of different parachute configurations were made, and a design best suited for the HAORB's needs was determined to provide for payload recovery after flight termination. In an effort to avoid possible payload damage, a landing system was also developed.

  19. The effects of energy beverages in counteracting the symptoms of mild hypoxia at legal general aviation altitudes

    NASA Astrophysics Data System (ADS)

    Bull, Daniel Mark

    The purpose of this thesis was to conduct preliminary research, in the form of a pilot study, concerning the natural effects of hypoxia compared to the effects of hypoxia experienced after the consumption of an energy beverage. The study evaluated the effects of hypoxia on FAA certificated pilots at a simulated legal general aviation altitude, utilizing the normobaric High Altitude Lab (HAL) located at Embry Riddle Aeronautical University, Daytona Beach, Florida. The researcher tested 11 subjects, who completed three simulated flight tasks within the HAL using the Frasca International Mentor Advanced Aviation Training Device (AATD). The flight tasks were completed after consuming Red BullRTM, MonsterRTM , or a placebo beverage. The researcher derived three test variables from core outputs of the AATD: lateral deviations from the glide slope, vertical deviations from the localizer, and airspeed deviations from the target speed of 100 knots. A repeated-measures ANOVA was carried out to determine effects of the beverages on the test variables. While results were non-significant, the researcher concluded that further research should be conducted with a larger sample.

  20. Pulmonary vascular remodelling in a high-altitude Aymara Indian

    NASA Astrophysics Data System (ADS)

    Heath, Donald; Williams, David

    1991-12-01

    A histological study of the pulmonary vasculature in a young male high-altitude Aymara Indian revealed four aspects of interest. There was muscularization of the terminal portion of the pulmonary arterial tree to involve pulmonary arterioles as small as 15 μm in diameter, thus forming a basis for the slightly increased pulmonary vascular resistance of native highlanders. Intimal longitudinal muscle was found in pulmonary arteries and arterioles and thought to be due to chronic alveolar hypoxia. Inner muscular tubes similar to those found in chronic obstructive lung disease were present. Pulmonary veins and venules also showed intimal muscularization suggesting that alveolar hypoxia affects vascular smooth muscle cells per se irrespective of their situation. The nature of the remodelling in a pulmonary blood vessel depends on a combination of hypoxia and haemodynamics.

  1. Increased Hypoxic Dose After Training at Low Altitude with 9h Per Night at 3000m Normobaric Hypoxia

    PubMed Central

    Carr, Amelia J.; Saunders, Philo U.; Vallance, Brent S.; Garvican-Lewis, Laura A.; Gore, Christopher J.

    2015-01-01

    This study examined effects of low altitude training and a live-high: train-low protocol (combining both natural and simulated modalities) on haemoglobin mass (Hbmass), maximum oxygen consumption (VO2max), time to exhaustion, and submaximal exercise measures. Eighteen elite-level race-walkers were assigned to one of two experimental groups; lowHH (low Hypobaric Hypoxia: continuous exposure to 1380 m for 21 consecutive days; n = 10) or a combined low altitude training and nightly Normobaric Hypoxia (lowHH+NHnight: living and training at 1380 m, plus 9 h.night-1 at a simulated altitude of 3000 m using hypoxic tents; n = 8). A control group (CON; n = 10) lived and trained at 600 m. Measurement of Hbmass, time to exhaustion and VO2max was performed before and after the training intervention. Paired samples t-tests were used to assess absolute and percentage change pre and post-test differences within groups, and differences between groups were assessed using a one-way ANOVA with least significant difference post-hoc testing. Statistical significance was tested at p < 0.05. There was a 3.7% increase in Hbmass in lowHH+NHnight compared with CON (p = 0.02). In comparison to baseline, Hbmass increased by 1.2% (±1.4%) in the lowHH group, 2.6% (±1.8%) in lowHH+NHnight, and there was a decrease of 0.9% (±4.9%) in CON. VO2max increased by ~4% within both experimental conditions but was not significantly greater than the 1% increase in CON. There was a ~9% difference in pre and post-intervention values in time to exhaustion after lowHH+NH-night (p = 0.03) and a ~8% pre to post-intervention difference (p = 0.006) after lowHH only. We recommend low altitude (1380 m) combined with sleeping in altitude tents (3000 m) as one effective alternative to traditional altitude training methods, which can improve Hbmass. Key points In some countries, it may not be possible to perform classical altitude training effectively, due to the low elevation at altitude training venues. An

  2. Increased Hypoxic Dose After Training at Low Altitude with 9h Per Night at 3000m Normobaric Hypoxia.

    PubMed

    Carr, Amelia J; Saunders, Philo U; Vallance, Brent S; Garvican-Lewis, Laura A; Gore, Christopher J

    2015-12-01

    This study examined effects of low altitude training and a live-high: train-low protocol (combining both natural and simulated modalities) on haemoglobin mass (Hbmass), maximum oxygen consumption (VO2max), time to exhaustion, and submaximal exercise measures. Eighteen elite-level race-walkers were assigned to one of two experimental groups; lowHH (low Hypobaric Hypoxia: continuous exposure to 1380 m for 21 consecutive days; n = 10) or a combined low altitude training and nightly Normobaric Hypoxia (lowHH+NHnight: living and training at 1380 m, plus 9 h.night(-1) at a simulated altitude of 3000 m using hypoxic tents; n = 8). A control group (CON; n = 10) lived and trained at 600 m. Measurement of Hbmass, time to exhaustion and VO2max was performed before and after the training intervention. Paired samples t-tests were used to assess absolute and percentage change pre and post-test differences within groups, and differences between groups were assessed using a one-way ANOVA with least significant difference post-hoc testing. Statistical significance was tested at p < 0.05. There was a 3.7% increase in Hbmass in lowHH+NHnight compared with CON (p = 0.02). In comparison to baseline, Hbmass increased by 1.2% (±1.4%) in the lowHH group, 2.6% (±1.8%) in lowHH+NHnight, and there was a decrease of 0.9% (±4.9%) in CON. VO2max increased by ~4% within both experimental conditions but was not significantly greater than the 1% increase in CON. There was a ~9% difference in pre and post-intervention values in time to exhaustion after lowHH+NH-night (p = 0.03) and a ~8% pre to post-intervention difference (p = 0.006) after lowHH only. We recommend low altitude (1380 m) combined with sleeping in altitude tents (3000 m) as one effective alternative to traditional altitude training methods, which can improve Hbmass. Key pointsIn some countries, it may not be possible to perform classical altitude training effectively, due to the low elevation at altitude training venues. An

  3. Elevated suicide rates at high altitude: sociodemographic and health issues may be to blame.

    PubMed

    Betz, Marian E; Valley, Morgan A; Lowenstein, Steven R; Hedegaard, Holly; Thomas, Deborah; Stallones, Lorann; Honigman, Benjamin

    2011-10-01

    Suicide rates are higher at high altitudes; some hypothesize that hypoxia is the cause. We examined 8,871 suicides recorded in 2006 in 15 states by the National Violent Death Reporting System, with the victim's home county altitude determined from the National Elevation Dataset through FIPS code matching. We grouped cases by altitude (low<1000m; middle=1000-1999m; high≥2000m). Of reported suicides, 5% were at high and 83% at low altitude, but unadjusted suicide rates per 100,000 population were higher at high (17.7) than at low (5.7) altitude. High and low altitude victims differed with respect to race, ethnicity, rural residence, intoxication, depressed mood preceding the suicide, firearm use and recent financial, job, legal, or interpersonal problems. Even after multivariate adjustment, there were significant differences in personal, mental health, and suicide characteristics among altitude groups. Compared to low altitude victims, high altitude victims had higher odds of having family or friends report of a depressed mood preceding the suicide (OR 1.78; 95%CI:1.46-2.17) and having a crisis within 2weeks before death (OR 2.00; 95%CI:1.63-1.46). Suicide victims at high and low altitudes differ significantly by multiple demographic, psychiatric, and suicide characteristics; these factors, rather than hypoxia or altitude itself, may explain increased suicide rates at high altitude. PMID:21883411

  4. The genetic architecture of adaptations to high altitude in Ethiopia.

    PubMed

    Alkorta-Aranburu, Gorka; Beall, Cynthia M; Witonsky, David B; Gebremedhin, Amha; Pritchard, Jonathan K; Di Rienzo, Anna

    2012-01-01

    Although hypoxia is a major stress on physiological processes, several human populations have survived for millennia at high altitudes, suggesting that they have adapted to hypoxic conditions. This hypothesis was recently corroborated by studies of Tibetan highlanders, which showed that polymorphisms in candidate genes show signatures of natural selection as well as well-replicated association signals for variation in hemoglobin levels. We extended genomic analysis to two Ethiopian ethnic groups: Amhara and Oromo. For each ethnic group, we sampled low and high altitude residents, thus allowing genetic and phenotypic comparisons across altitudes and across ethnic groups. Genome-wide SNP genotype data were collected in these samples by using Illumina arrays. We find that variants associated with hemoglobin variation among Tibetans or other variants at the same loci do not influence the trait in Ethiopians. However, in the Amhara, SNP rs10803083 is associated with hemoglobin levels at genome-wide levels of significance. No significant genotype association was observed for oxygen saturation levels in either ethnic group. Approaches based on allele frequency divergence did not detect outliers in candidate hypoxia genes, but the most differentiated variants between high- and lowlanders have a clear role in pathogen defense. Interestingly, a significant excess of allele frequency divergence was consistently detected for genes involved in cell cycle control and DNA damage and repair, thus pointing to new pathways for high altitude adaptations. Finally, a comparison of CpG methylation levels between high- and lowlanders found several significant signals at individual genes in the Oromo.

  5. Long-term stay at low altitude (1,200 m) promotes better hypoxia adaptation and performance.

    PubMed

    Singh, Krishan; Gupta, R K; Soree, Poonam; Rai, Lokesh; Himashree, G

    2014-01-01

    Acute exposure to high altitude hypoxia is known to decrease physical performance. The exercise performance increases during moderate altitude training (2000-3000 m) but benefits are overshadowed by adverse effect associated with hypoxia. Therefore, the study was designed to address whether low altitude of 1200 m could increase exercise performance without any adverse effects and a correlation with stay period (stay > 6 month) was optimized. In the present study residents of lower altitude (1200 m altitude) (LA) and sea level (SL) residents were subjected to sub-maximal exercise test and their exercise response in terms of post-exercise heart rate and change in oxygen saturation was compared. Post-exercise peak heart rate (129.89 ± 13.42 vs 146.00 ± 11.81, p < 0.05) was significantly lower and arterial oxygen saturation (SpO2) after exercise had a significant fall (95.3 ± 2.26% vs 98 ± 0% p < 0.001) in LA residents. The hematological parameters like hemoglobin (Hb) and hematocrit (Hct) taken as markers of physiological adaptation, were also found to be significantly higher in LA as compared to SL residents (Hb 16.13 ± 0.70 vs 14.2 ± 0.87, p < 0.001 and Hct 47.4 ± ?2.08 vs 44.0 ± ?0.72, p <0.001). Overall, the study highlights that physiological adaptation at 1200 m results into a better exercise response and hematological benefit compared to sea level residents.

  6. [Altitude adaptation. IV. Fertility and reproduction at high altitudes].

    PubMed

    Eckes, L

    1976-01-01

    High altitude populations have been reproducing for thousands of years. The mean total fertility is comparable to the respective mean values of the whole populations or is even higher. On the other hand, newcomers from sea level seem to have difficulties reproducing in high altitude, especially if they are caucasian. Cattle and other animals fail to reproduce to some extent (due to degeneration of the testes, asoospermia, abortation etc.), which can only be avoided after crossbreeding with aclimatized strains in several generations. But successful gestation in altitudes above 3000 metres is different from sea level gestation in several aspects, which may be important for the survival of mother and child, thus leaving open the question of selective pressure. The mean birth weight of man and animals is reduced, while the mean palcental weight is greater (relatively and absolutely) due to enlargement of the capillary volume. Placenta proves to be on higher risk for developing infarcts (the more in number and extetion, the greater the caucasian admixture). Due to the tendency to a greater extention of the surface, the rate of placenta praevia is extremely high (27%). The lower birth weight corresponds to a higher neonatal mortality, progressing with increasing altitude. Additional to the high altitude stress including the factors to which the newborn are exposed, such as cold, nuturtional deficiencies etc., particular socio-economic conditions influence the differential mortality. In the Bolivian mining-areas, mortality during the first year of life rises to 50%. Only high fertility rates compensate this loss so that high altitude population growth rates do not vary with the altitude.

  7. High Altitude Cooking and Food Safety

    MedlinePlus

    ... Where to Place the Food Thermometer Recommended Internal Temperatures Is egg cookery affected at high altitudes? Is ... atmospheric pressure — affects both the time and the temperature of most everything that's cooked. Where the altitude ...

  8. Increase in carbohydrate utilization in high-altitude Andean mice.

    PubMed

    Schippers, Marie-Pierre; Ramirez, Oswaldo; Arana, Margarita; Pinedo-Bernal, Percy; McClelland, Grant B

    2012-12-18

    The low oxygen levels at high altitude are a potent and unavoidable physiological stressor to which highland mammals must adapt. One hypothesized adaptation to high altitude is an increased reliance on carbohydrates to support aerobic activities. Based on stoichiometries of combustion, ATP yield per mole of oxygen from carbohydrates is approximately 15% higher than from lipids (observed difference closer to 30%), and increased carbohydrate use represents an important oxygen-saving strategy that may be under high selective pressure. Although this hypothesis was first proposed nearly 30 years ago, the in vivo patterns of whole-body fuel use during exercise remain undefined for any highland mammal (including humans). Here we use a powerful multispecies approach to show that wild-caught high-altitude (4,000-4,500 m) native species of mice (Phyllotis andium and Phyllotis xanthopygus) from the Peruvian Andes use proportionately more carbohydrates and have higher oxidative capacities of cardiac muscles compared to closely related low-altitude (100-300 m) native counterparts (Phyllotis amicus and Phyllotis limatus). These results strongly infer that highland Phyllotis have evolved a metabolic strategy to economize oxygen when performing energy-demanding tasks at altitude. This study provides compelling evidence of adjustments in fuel use as an adaptation to high-altitude hypoxia in mammals. PMID:23219722

  9. Ancestry explains the blunted ventilatory response to sustained hypoxia and lower exercise ventilation of Quechua altitude natives.

    PubMed

    Brutsaert, Tom D; Parra, Esteban J; Shriver, Mark D; Gamboa, Alfredo; Rivera-Ch, Maria; León-Velarde, Fabiola

    2005-07-01

    Andean high-altitude (HA) natives have a low (blunted) hypoxic ventilatory response (HVR), lower effective alveolar ventilation, and lower ventilation (VE) at rest and during exercise compared with acclimatized newcomers to HA. Despite blunted chemosensitivity and hypoventilation, Andeans maintain comparable arterial O(2) saturation (Sa(O(2))). This study was designed to evaluate the influence of ancestry on these trait differences. At sea level, we measured the HVR in both acute (HVR-A) and sustained (HVR-S) hypoxia in a sample of 32 male Peruvians of mainly Quechua and Spanish origins who were born and raised at sea level. We also measured resting and exercise VE after 10-12 h of exposure to altitude at 4,338 m. Native American ancestry proportion (NAAP) was assessed for each individual using a panel of 80 ancestry-informative molecular markers (AIMs). NAAP was inversely related to HVR-S after 10 min of isocapnic hypoxia (r = -0.36, P = 0.04) but was not associated with HVR-A. In addition, NAAP was inversely related to exercise VE (r = -0.50, P = 0.005) and ventilatory equivalent (VE/Vo(2), r = -0.51, P = 0.004) measured at 4,338 m. Thus Quechua ancestry may partly explain the well-known blunted HVR (10, 35, 36, 57, 62) at least to sustained hypoxia, and the relative exercise hypoventilation at altitude of Andeans compared with European controls. Lower HVR-S and exercise VE could reflect improved gas exchange and/or attenuated chemoreflex sensitivity with increasing NAAP. On the basis of these ancestry associations and on the fact that developmental effects were completely controlled by study design, we suggest both a genetic basis and an evolutionary origin for these traits in Quechua.

  10. Why Are High Altitude Natives So Strong at High Altitude? Nature vs. Nurture: Genetic Factors vs. Growth and Development.

    PubMed

    Brutsaert, Tom

    2016-01-01

    Among high-altitude natives there is evidence of a general hypoxia tolerance leading to enhanced performance and/or increased capacity in several important domains. These domains likely include an enhanced physical work capacity, an enhanced reproductive capacity, and an ability to resist several common pathologies of chronic high-altitude exposure. The "strength" of the high-altitude native in this regard may have both a developmental and a genetic basis, although there is better evidence for the former (developmental effects) than for the latter. For example, early-life hypoxia exposure clearly results in lung growth and remodeling leading to an increased O2 diffusing capacity in adulthood. Genetic research has yet to reveal a population genetic basis for enhanced capacity in high-altitude natives, but several traits are clearly under genetic control in Andean and Tibetan populations e.g., resting and exercise arterial O2 saturation (SaO2). This chapter reviews the effects of nature and nurture on traits that are relevant to the process of gas exchange, including pulmonary volumes and diffusion capacity, the maximal oxygen consumption (VO2max), the SaO2, and the alveolar-arterial oxygen partial pressure difference (A-aDO2) during exercise. PMID:27343091

  11. Why Are High Altitude Natives So Strong at High Altitude? Nature vs. Nurture: Genetic Factors vs. Growth and Development.

    PubMed

    Brutsaert, Tom

    2016-01-01

    Among high-altitude natives there is evidence of a general hypoxia tolerance leading to enhanced performance and/or increased capacity in several important domains. These domains likely include an enhanced physical work capacity, an enhanced reproductive capacity, and an ability to resist several common pathologies of chronic high-altitude exposure. The "strength" of the high-altitude native in this regard may have both a developmental and a genetic basis, although there is better evidence for the former (developmental effects) than for the latter. For example, early-life hypoxia exposure clearly results in lung growth and remodeling leading to an increased O2 diffusing capacity in adulthood. Genetic research has yet to reveal a population genetic basis for enhanced capacity in high-altitude natives, but several traits are clearly under genetic control in Andean and Tibetan populations e.g., resting and exercise arterial O2 saturation (SaO2). This chapter reviews the effects of nature and nurture on traits that are relevant to the process of gas exchange, including pulmonary volumes and diffusion capacity, the maximal oxygen consumption (VO2max), the SaO2, and the alveolar-arterial oxygen partial pressure difference (A-aDO2) during exercise.

  12. Physiological and Clinical Implications of Adrenergic Pathways at High Altitude.

    PubMed

    Richalet, Jean-Paul

    2016-01-01

    The adrenergic system is part of a full array of mechanisms allowing the human body to adapt to the hypoxic environment. Triggered by the stimulation of peripheral chemoreceptors, the adrenergic centers in the medulla are activated in acute hypoxia and augment the adrenergic drive to the organs, especially to the heart, leading to tachycardia. With prolonged exposure to altitude hypoxia, the adrenergic drive persists, as witnessed by elevated blood concentrations of catecholamines and nerve activity in adrenergic fibers. In response to this persistent stimulation, the pathways leading to the activation of adenylate cyclase are modified. A downregulation of β-adrenergic and adenosinergic receptors is observed, while muscarinic receptors are upregulated. The expression and activity of Gi and Gs proteins are modified, leading to a decreased response of adenylate cyclase activity to adrenergic stimulation. The clinical consequences of these cellular and molecular changes are of importance, especially for exercise performance and protection of heart function. The decrease in maximal exercise heart rate in prolonged hypoxia is fully accounted for the observed changes in adrenergic and muscarinic pathways. The decreased heart rate response to isoproterenol infusion is another marker of the desensitization of adrenergic pathways. These changes can be considered as mechanisms protecting the heart from a too high oxygen consumption in conditions where the oxygen availability is severely reduced. Similarly, intermittent exposure to hypoxia has been shown to protect the heart from an ischemic insult with similar mechanisms involving G proteins and downregulation of β receptors. Other pathways with G proteins are concerned in adaptation to hypoxia, such as lactate release by the muscles and renal handling of calcium. Altogether, the activation of the adrenergic system is useful for the acute physiological response to hypoxia. With prolonged exposure to hypoxia, the autonomous

  13. High-altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdi, Renee Anna

    1991-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000+ ft, which is beyond the capabilities of the ER-2, NASA's current high-altitude reconnaissance aircraft. This project is geared to designing an aircraft that can study the ozone layer. The aircraft must be able to satisfy four mission profiles. The first is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.m. at 100,000 ft with a 2500-lb payload. The second mission is also a polar mission with a decreased altitude and an increased payload. For the third mission, the aircraft will take off at NASA Ames, cruise at 100,000 ft, and land in Chile. The final mission requires the aircraft to make an excursion to 120,000 ft. All four missions require that a subsonic Mach number be maintained because of constraints imposed by the air sampling equipment. Three aircraft configurations were determined to be the most suitable for meeting the requirements. The performance of each is analyzed to investigate the feasibility of the mission requirements.

  14. Evolutionary adaptation to high altitude: a view from in utero

    PubMed Central

    Julian, Colleen Glyde; Wilson, Megan J.; Moore, Lorna G.

    2010-01-01

    A primary focus within biological anthropology has been to elucidate the processes of evolutionary adaptation. A. Roberto Frisancho helped move anthropology towards more mechanistic explanations of human adaptation by drawing attention to the importance of the functional relevance of human variation. Using the natural laboratory of high altitude, he and others asked whether the unique physiology of indigenous high-altitude residents was the result of acclimatization, developmental plasticity and/or genetic adaptation in response to the high-altitude environment. We approach the question of human adaptation to high altitude from a somewhat unique vantage point; namely, by examining physiological characteristics – pregnancy and pregnancy outcome -- that are most closely associated with reproductive fitness. Here we review the potent example of high-altitude native population’s resistance to hypoxia-associated reductions in birth weight, which is often associated with higher infant morbidity and mortality at high altitude. With the exception of two recent publications, these comparative birth weight studies have utilized surnames, self-identification and/or linguistic characteristics to assess ancestry, and none have linked ‘advantageous’ phenotypes to specific genetic variations. Recent advancements in genetic and statistical tools have enabled us to assess individual ancestry with higher resolution, identify the genetic basis of complex phenotypes and to infer the effect of natural selection on specific gene regions. Using these technologies our studies are now directed to determine the genetic variations that underlie the mechanisms by which high-altitude ancestry protects fetal growth and, in turn, to further our understanding of evolutionary processes involved in human adaptation to high altitude. PMID:19367578

  15. [High altitude stay and air travel in coronary heart disease].

    PubMed

    Allemann, Y; Saner, H; Meier, B

    1998-04-25

    Acute exposure to high altitude produces hypoxia-associated stimulation of the sympathetic nervous system. This response is further enhanced by physical activity and induces an increase in heart rate and blood pressure. Consequently, cardiac work, myocardial oxygen consumption, and coronary blood flow are also increased. During the first 4 days of acute exposure to moderate or high altitude, coronary patients are at greatest risk of untoward events. Gradual ascent, early limitation of activity to a lower level than tolerated at low altitude, pre-ascent physical conditioning and rigorous blood pressure control should all help to minimise the cardiac risk. At altitudes of 2500 to 3000 m or lower, an asymptomatic coronary patient with good exercise tolerance, without exercise induced signs or symptoms of ischemia, and with an ejection fraction of the left ventricle > 50%, is at very low risk. However, several days' acclimatization before high-level activity at moderate or high altitude is recommended. High risk coronary patients should be investigated more carefully and precautionary measures should be more stringent. Left and right cardiac function and pulmonary artery pressure are the most helpful parameters for evaluation and counselling of patients with non-ischemic heart disease who plan to ascend to moderate or high altitudes. When advising patients who intend to fly as passengers in commercial aircraft, it is important to know that in-flight atmospheric pressure conditions in commercial jet aircraft approach altitude equivalents of 1500 to 2400 m. Propeller-driven planes are rarely pressurized but usually fly at altitudes below 3300 m. Relatively strict contraindications for air travel by coronary patients are uncomplicated myocardial infarction within the last 2 weeks, complicated myocardial infarction within the last 6 weeks, unstable angina, thoracic surgery within the last 3 weeks, and poorly controlled congestive heart failure, arrhythmia, or hypertension.

  16. Analysis of high-altitude de-acclimatization syndrome after exposure to high altitudes: a cluster-randomized controlled trial.

    PubMed

    He, Binfeng; Wang, Jianchun; Qian, Guisheng; Hu, Mingdong; Qu, Xinming; Wei, Zhenghua; Li, Jin; Chen, Yan; Chen, Huaping; Zhou, Qiquan; Wang, Guansong

    2013-01-01

    The syndrome of high-altitude de-acclimatization commonly takes place after long-term exposure to high altitudes upon return to low altitudes. The syndrome severely affects the returnee's quality of life. However, little attention has been paid to careful characterization of the syndrome and their underlying mechanisms. Male subjects from Chongqing (n = 67, 180 m) and Kunming (n = 70, 1800 m) visited a high-altitude area (3650 m) about 6 months and then returned to low-altitude. After they came back, all subjects were evaluated for high-altitude de-acclimatization syndrome on the 3(rd), 50(th), and 100(th). Symptom scores, routine blood and blood gas tests, and myocardial zymograms assay were used for observation their syndrome. The results showed that the incidence and severity of symptoms had decreased markedly on the 50(th) and 100(th) days, compared with the 3(rd) day. The symptom scores and incidence of different symptoms were lower among subjects returning to Kunming than among those returning to Chongqing. On the 3(rd) day, RBC, Hb, Hct, CK, CK-MB, and LDH values were significantly lower than values recorded at high altitudes, but they were higher than baseline values. On the 50(th) day, these values were not different from baseline values, but LDH levels did not return to baseline until the 100(th) day. These data show that, subjects who suffered high-altitude de-acclimatization syndrome, the recovery fully processes takes a long time (≥ 100(th) days). The appearance of the syndrome is found to be related to the changes in RBC, Hb, Hct, CK, CK-MB, and LDH levels, which should be caused by reoxygenation after hypoxia.

  17. High fat diet exacerbates vascular endothelial dysfunction in rats exposed to continuous hypobaric hypoxia.

    PubMed

    Zhao, Yan-Xia; Tang, Feng; Ga, Qin; Wuren, Tana; Wang, Ya-Ping; Rondina, Matthew T; Ge, Ri-Li

    2015-02-13

    Independently, a high fat diet and hypoxia are associated with vascular endothelial dysfunction (VED) and often occur concurrently in patients. Nevertheless, the effects of a high fat diet on vascular endothelial function combined with hypoxia, a situation occurring with increasing frequency in many parts of the world, remain largely unknown. We investigated the effects of a high fat diet on vascular endothelial function in rats exposed to continuous hypoxia for 4 weeks. Seventy two male Sprague-Dawley rats were randomly divided into 3 groups: a hypoxia group fed regular chow, a combined hypoxia and high fat diet (HFD) group, and for comparison, rats maintained in normoxia, regular chow conditions were set as baseline (BL) group. The experimental data of BL group were obtained at beginning of hypoxia given in the other groups. Continuous hypoxia was induced in a hypobaric chamber maintained at an altitude of 5000 m. Compared to hypoxic conditions alone, hypoxia plus a HFD prevented adaptive changes in plasma nitric oxide (NOx) levels and caused earlier and more severe changes in aortic endothelial structures. Functionally, hypoxia plus a HFD resulted in impaired endothelium-dependent vasorelaxation responses to acetylcholine and altered the bioavailability of the nitric oxide synthase (NOS) substrate L-Arginine. At the molecular level, hypoxia plus a HFD blunted increases in endothelial NOS (eNOS) mRNA and protein in aortic endothelial tissue. Taken together, our findings demonstrate that in the setting of hypoxia, a high fat diet leads to earlier and more severe VED than hypoxia alone. These data have important implications for populations residing at high-altitude, as dietary patterns shift towards increased fat intake. PMID:25603049

  18. High-altitude cerebral edema with absence of headache.

    PubMed

    Thomassen, Oyvind; Skaiaa, Sven Chr

    2007-01-01

    Headache is the cardinal symptom of acute mountain sickness (AMS). The headache normally worsens, with increased cerebral affection and the development of high-altitude cerebral edema (HACE). A Norwegian expedition aimed to climb Baruntse (7129 m) in Nepal in 2003. At 5400 m a 35-year-old man felt exhausted. The next day he aborted his attempt at further climbing as a result of extreme fatigue. Over the next 24 hours he developed cough, dyspnea, and severe hypoxia before progressing to ataxia and blurred vision. At no point did he experience headache or nausea. The patient was evacuated by helicopter. He improved immediately after descent and recovered completely within a week. The speed of progression from AMS to HACE varies. Abrupt onset of HACE is occasionally reported. High-altitude pulmonary edema (HAPE) may induce severe hypoxia that can lead to rapid development of HACE. High-altitude cerebral edema in the setting of HAPE was the most likely diagnosis despite the unusual lack of headache. Rapid onset of HAPE with subsequent severe desaturation should raise awareness of the development of HACE, even in the absence of headache. PMID:17447714

  19. Hormonal contraceptives and travel to high altitude.

    PubMed

    Keyes, Linda E

    2015-03-01

    Women frequently ask about the safety and efficacy of using hormonal contraception (HC), either oral contraceptive pills (OC) or other forms, when traveling to high altitude locales. What are the risks and benefits of using HC at high altitude? Does HC affect acclimatization, exercise performance, or occurrence of acute mountain sickness? This article reviews current data regarding the risks and benefits of HC at high altitude, both demonstrated and theoretical, with the aim of helping health care providers to advise women traveling above 2500 meters. Most healthy women can safely use HC when traveling to high altitude, but should be aware of the potential risks and inconveniences.

  20. Hormonal contraceptives and travel to high altitude.

    PubMed

    Keyes, Linda E

    2015-03-01

    Women frequently ask about the safety and efficacy of using hormonal contraception (HC), either oral contraceptive pills (OC) or other forms, when traveling to high altitude locales. What are the risks and benefits of using HC at high altitude? Does HC affect acclimatization, exercise performance, or occurrence of acute mountain sickness? This article reviews current data regarding the risks and benefits of HC at high altitude, both demonstrated and theoretical, with the aim of helping health care providers to advise women traveling above 2500 meters. Most healthy women can safely use HC when traveling to high altitude, but should be aware of the potential risks and inconveniences. PMID:25759908

  1. AltitudeOmics: The Integrative Physiology of Human Acclimatization to Hypobaric Hypoxia and Its Retention upon Reascent

    PubMed Central

    Subudhi, Andrew W.; Bourdillon, Nicolas; Bucher, Jenna; Davis, Christopher; Elliott, Jonathan E.; Eutermoster, Morgan; Evero, Oghenero; Fan, Jui-Lin; Houten, Sonja Jameson-Van; Julian, Colleen G.; Kark, Jonathan; Kark, Sherri; Kayser, Bengt; Kern, Julia P.; Kim, See Eun; Lathan, Corinna; Laurie, Steven S.; Lovering, Andrew T.; Paterson, Ryan; Polaner, David M.; Ryan, Benjamin J.; Spira, James L.; Tsao, Jack W.; Wachsmuth, Nadine B.; Roach, Robert C.

    2014-01-01

    An understanding of human responses to hypoxia is important for the health of millions of people worldwide who visit, live, or work in the hypoxic environment encountered at high altitudes. In spite of dozens of studies over the last 100 years, the basic mechanisms controlling acclimatization to hypoxia remain largely unknown. The AltitudeOmics project aimed to bridge this gap. Our goals were 1) to describe a phenotype for successful acclimatization and assess its retention and 2) use these findings as a foundation for companion mechanistic studies. Our approach was to characterize acclimatization by measuring changes in arterial oxygenation and hemoglobin concentration [Hb], acute mountain sickness (AMS), cognitive function, and exercise performance in 21 subjects as they acclimatized to 5260 m over 16 days. We then focused on the retention of acclimatization by having subjects reascend to 5260 m after either 7 (n = 14) or 21 (n = 7) days at 1525 m. At 16 days at 5260 m we observed: 1) increases in arterial oxygenation and [Hb] (compared to acute hypoxia: PaO2 rose 9±4 mmHg to 45±4 while PaCO2 dropped a further 6±3 mmHg to 21±3, and [Hb] rose 1.8±0.7 g/dL to 16±2 g/dL; 2) no AMS; 3) improved cognitive function; and 4) improved exercise performance by 8±8% (all changes p<0.01). Upon reascent, we observed retention of arterial oxygenation but not [Hb], protection from AMS, retention of exercise performance, less retention of cognitive function; and noted that some of these effects lasted for 21 days. Taken together, these findings reveal new information about retention of acclimatization, and can be used as a physiological foundation to explore the molecular mechanisms of acclimatization and its retention. PMID:24658407

  2. AltitudeOmics: the integrative physiology of human acclimatization to hypobaric hypoxia and its retention upon reascent.

    PubMed

    Subudhi, Andrew W; Bourdillon, Nicolas; Bucher, Jenna; Davis, Christopher; Elliott, Jonathan E; Eutermoster, Morgan; Evero, Oghenero; Fan, Jui-Lin; Jameson-Van Houten, Sonja; Julian, Colleen G; Kark, Jonathan; Kark, Sherri; Kayser, Bengt; Kern, Julia P; Kim, See Eun; Lathan, Corinna; Laurie, Steven S; Lovering, Andrew T; Paterson, Ryan; Polaner, David M; Ryan, Benjamin J; Spira, James L; Tsao, Jack W; Wachsmuth, Nadine B; Roach, Robert C

    2014-01-01

    An understanding of human responses to hypoxia is important for the health of millions of people worldwide who visit, live, or work in the hypoxic environment encountered at high altitudes. In spite of dozens of studies over the last 100 years, the basic mechanisms controlling acclimatization to hypoxia remain largely unknown. The AltitudeOmics project aimed to bridge this gap. Our goals were 1) to describe a phenotype for successful acclimatization and assess its retention and 2) use these findings as a foundation for companion mechanistic studies. Our approach was to characterize acclimatization by measuring changes in arterial oxygenation and hemoglobin concentration [Hb], acute mountain sickness (AMS), cognitive function, and exercise performance in 21 subjects as they acclimatized to 5260 m over 16 days. We then focused on the retention of acclimatization by having subjects reascend to 5260 m after either 7 (n = 14) or 21 (n = 7) days at 1525 m. At 16 days at 5260 m we observed: 1) increases in arterial oxygenation and [Hb] (compared to acute hypoxia: PaO2 rose 9±4 mmHg to 45±4 while PaCO2 dropped a further 6±3 mmHg to 21±3, and [Hb] rose 1.8±0.7 g/dL to 16±2 g/dL; 2) no AMS; 3) improved cognitive function; and 4) improved exercise performance by 8±8% (all changes p<0.01). Upon reascent, we observed retention of arterial oxygenation but not [Hb], protection from AMS, retention of exercise performance, less retention of cognitive function; and noted that some of these effects lasted for 21 days. Taken together, these findings reveal new information about retention of acclimatization, and can be used as a physiological foundation to explore the molecular mechanisms of acclimatization and its retention.

  3. Identification of novel serum peptide biomarkers for high-altitude adaptation: a comparative approach

    NASA Astrophysics Data System (ADS)

    Yang, Juan; Li, Wenhua; Liu, Siyuan; Yuan, Dongya; Guo, Yijiao; Jia, Cheng; Song, Tusheng; Huang, Chen

    2016-05-01

    We aimed to identify serum biomarkers for screening individuals who could adapt to high-altitude hypoxia at sea level. HHA (high-altitude hypoxia acclimated; n = 48) and HHI (high-altitude hypoxia illness; n = 48) groups were distinguished at high altitude, routine blood tests were performed for both groups at high altitude and at sea level. Serum biomarkers were identified by comparing serum peptidome profiling between HHI and HHA groups collected at sea level. Routine blood tests revealed the concentration of hemoglobin and red blood cells were significantly higher in HHI than in HHA at high altitude. Serum peptidome profiling showed that ten significantly differentially expressed peaks between HHA and HHI at sea level. Three potential serum peptide peaks (m/z values: 1061.91, 1088.33, 4057.63) were further sequence identified as regions of the inter-α trypsin inhibitor heavy chain H4 fragment (ITIH4 347–356), regions of the inter-α trypsin inhibitor heavy chain H1 fragment (ITIH1 205–214), and isoform 1 of fibrinogen α chain precursor (FGA 588–624). Expression of their full proteins was also tested by ELISA in HHA and HHI samples collected at sea level. Our study provided a novel approach for identifying potential biomarkers for screening people at sea level who can adapt to high altitudes.

  4. Identification of novel serum peptide biomarkers for high-altitude adaptation: a comparative approach.

    PubMed

    Yang, Juan; Li, Wenhua; Liu, Siyuan; Yuan, Dongya; Guo, Yijiao; Jia, Cheng; Song, Tusheng; Huang, Chen

    2016-01-01

    We aimed to identify serum biomarkers for screening individuals who could adapt to high-altitude hypoxia at sea level. HHA (high-altitude hypoxia acclimated; n = 48) and HHI (high-altitude hypoxia illness; n = 48) groups were distinguished at high altitude, routine blood tests were performed for both groups at high altitude and at sea level. Serum biomarkers were identified by comparing serum peptidome profiling between HHI and HHA groups collected at sea level. Routine blood tests revealed the concentration of hemoglobin and red blood cells were significantly higher in HHI than in HHA at high altitude. Serum peptidome profiling showed that ten significantly differentially expressed peaks between HHA and HHI at sea level. Three potential serum peptide peaks (m/z values: 1061.91, 1088.33, 4057.63) were further sequence identified as regions of the inter-α trypsin inhibitor heavy chain H4 fragment (ITIH4 347-356), regions of the inter-α trypsin inhibitor heavy chain H1 fragment (ITIH1 205-214), and isoform 1 of fibrinogen α chain precursor (FGA 588-624). Expression of their full proteins was also tested by ELISA in HHA and HHI samples collected at sea level. Our study provided a novel approach for identifying potential biomarkers for screening people at sea level who can adapt to high altitudes.

  5. Jupiter's High-Altitude Clouds

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Multispectral Visible Imaging Camera (MVIC) snapped this incredibly detailed picture of Jupiter's high-altitude clouds starting at 06:00 Universal Time on February 28, 2007, when the spacecraft was only 2.3 million kilometers (1.4 million miles) from the solar system's largest planet. Features as small as 50 kilometers (30 miles) are visible. The image was taken through a narrow filter centered on a methane absorption band near 890 nanometers, a considerably redder wavelength than what the eye can see. Images taken through this filter preferentially pick out clouds that are relatively high in the sky of this gas giant planet because sunlight at the wavelengths transmitted by the filter is completely absorbed by the methane gas that permeates Jupiter's atmosphere before it can reach the lower clouds.

    The image reveals a range of diverse features. The south pole is capped with a haze of small particles probably created by the precipitation of charged particles into the polar regions during auroral activity. Just north of the cap is a well-formed anticyclonic vortex with rising white thunderheads at its core. Slightly north of the vortex are the tendrils of some rather disorganized storms and more pinpoint-like thunderheads. The dark 'measles' that appear a bit farther north are actually cloud-free regions where light is completely absorbed by the methane gas and essentially disappears from view. The wind action considerably picks up in the equatorial regions where giant plumes are stretched into a long wave pattern. Proceeding north of the equator, cirrus-like clouds are shredded by winds reaching speeds of up to 400 miles per hour, and more pinpoint-like thunderheads are visible. Although some of the famous belt and zone structure of Jupiter's atmosphere is washed out when viewed at this wavelength, the relatively thin North Temperate Belt shows up quite nicely, as does a series of waves just north of the belt. The north polar region of

  6. Psychological testing at high altitudes.

    PubMed

    Nelson, M

    1982-02-01

    Psychological testing was done on 20 subjects at various altitudes (sea level, 3,8,10 m, and 5,000 m) during a 35-d mountaineering expedition to Denali (Mt. McKinley). Intellectual functioning and personality changes were studied. While little variation was noted at the lower altitude, at 5,000 m there was a marked deterioration in cognitive ability. This was accompanied by a sharp increase in paranoia and obsessive-compulsiveness and smaller increases in depression and hostility.

  7. The physiology and biomechanics of avian flight at high altitude.

    PubMed

    Altshuler, Douglas L; Dudley, Robert

    2006-02-01

    Many birds fly at high altitude, either during long-distance flights or by virtue of residence in high-elevation habitats. Among the many environmental features that vary systematically with altitude, five have significant consequences for avian flight performance: ambient wind speeds, air temperature, humidity, oxygen availability, and air density. During migratory flights, birds select flight altitudes that minimize energy expenditure via selection of advantageous tail- and cross-winds. Oxygen partial pressure decreases substantially to as little as 26% of sea-level values for the highest altitudes at which birds migrate, whereas many taxa reside above 3000 meters in hypoxic air. Birds exhibit numerous adaptations in pulmonary, cardiovascular, and muscular systems to alleviate such hypoxia. The systematic decrease in air density with altitude can lead to a benefit for forward flight through reduced drag but imposes an increased aerodynamic demand for hovering by degrading lift production and simultaneously elevating the induced power requirements of flight. This effect has been well-studied in the hovering flight of hummingbirds, which occur throughout high-elevation habitats in the western hemisphere. Phylogenetically controlled studies have shown that hummingbirds compensate morphologically for such hypodense air through relative increases in wing size, and kinematically via increased stroke amplitude during the wingbeat. Such compensatory mechanisms result in fairly constant power requirements for hovering at different elevations, but decrease the margin of excess power available for other flight behaviors.

  8. Human nutrition in cold and high terrestrial altitudes

    NASA Astrophysics Data System (ADS)

    Srivastava, K. K.; Kumar, Ratan

    1992-03-01

    The calorie and nutritional requirements for a man working in an alien hostile environment of cold regions and high altitude are described and compared to those of normal requirements. Carbohydrates, fats and vitamins fulfilling the caloric and nutritional requirements are generally available in adequate amounts except under conditions of appetite loss. However, the proteins and amino acids should be provided in such a way as to meet the altered behavioral and metabolic requirements. Work in extreme cold requires fulfilling enhanced calorie needs. In high mountainous regions, cold combined with hypoxia produced loss of appetite and necessitated designing of special foods.

  9. Human high-altitude adaptation: forward genetics meets the HIF pathway

    PubMed Central

    Bigham, Abigail W.

    2014-01-01

    Humans have adapted to the chronic hypoxia of high altitude in several locations, and recent genome-wide studies have indicated a genetic basis. In some populations, genetic signatures have been identified in the hypoxia-inducible factor (HIF) pathway, which orchestrates the transcriptional response to hypoxia. In Tibetans, they have been found in the HIF2A (EPAS1) gene, which encodes for HIF-2α, and the prolyl hydroxylase domain protein 2 (PHD2, also known as EGLN1) gene, which encodes for one of its key regulators, PHD2. High-altitude adaptation may be due to multiple genes that act in concert with one another. Unraveling their mechanism of action can offer new therapeutic approaches toward treating common human diseases characterized by chronic hypoxia. PMID:25319824

  10. High altitude aircraft flight tests

    NASA Astrophysics Data System (ADS)

    Helmken, Henry; Emmons, Peter; Homeyer, David

    1996-03-01

    In order to make low earth orbit L-band propagation measurements and test new voice communication concepts, a payload was proposed and accepted for flight aboard the COMET (now METEOR) spacecraft. This Low Earth Orbiting EXperiment payload (LEOEX) was designed and developed by Motorola Inc. and sponsored by the Space Communications Technology Center (SCTC), a NASA Center for the Commercial Development of Space (CCDS) located at Florida Atlantic University. In order to verify the LEOEX payload for satellite operation and obtain some preliminary propagation data, a series of 9 high altitude aircraft (SR-71 and ER-2) flight tests were conducted. These flights took place during a period of 7 months, from October 1993 to April 1994. This paper will summarize the operation of the LEOEX payload and the particular configuration used for these flights. The series of flyby tests were very successful and demonstrated how bi-directional, Time Division Multiple Access (TDMA) voice communication will work in space-to-ground L-band channels. The flight tests also acquired propagation data which will be representative of L-band Low Earth Orbiting (LEO) communication systems. In addition to verifying the LEOEX system operation, it also uncovered and ultimately aided the resolution of several key technical issues associated with the payload.

  11. Training-dependent cognitive advantage is suppressed at high altitude.

    PubMed

    Li, Peng; Zhang, Gang; You, Hai-Yan; Zheng, Ran; Gao, Yu-Qi

    2012-06-25

    Ascent to high altitude is associated with decreases in cognitive function and work performance as a result of hypoxia. Some workers with special jobs typically undergo intensive mental training because they are expected to be agile, stable and error-free in their job performance. The purpose of this study was to determine the risk to cognitive function acquired from training following hypoxic exposure. The results of WHO neurobehavioral core tests battery (WHO-NCTB) and Raven's standard progressive matrices (RSPM) tests of a group of 54 highly trained military operators were compared with those of 51 non-trained ordinary people and were investigated at sea level and on the fifth day after arrival at high altitudes (3900m). Meanwhile, the plasma levels of brain-derived neurotrophic factor (BDNF), interleukin 1β (IL-1β) and vascular endothelial growth factor (VEGF) were examined. The result showed that at sea level, the trained group exhibited significantly better performance on neurobehavioral and RSPM tests. At high altitude, both groups had decreased accuracy in most cognitive tests and took longer to finish them. More importantly, the highly trained subjects showed more substantial declines than the non-trained subjects in visual reaction accuracy, auditory reaction speed, digit symbol scores, ability to report correct dots in a pursuit aiming test and total RSPM scores. This means that the training-dependent cognitive advantages in these areas were suppressed at high altitudes. The above phenomenon maybe associated with decreased BDNF and elevated inflammatory factor during hypoxia, and other mechanisms could not be excluded.

  12. High Altitude Illnesses in Hawai‘i

    PubMed Central

    2014-01-01

    High Altitude Headache (HAH), Acute Mountain Sickness (AMS), and High Altitude Cerebral Edema (HACE) are all high altitude related illnesses in order of severity from the mildly symptomatic to the potentially life-threatening. High altitude illnesses occur when travelers ascend to high altitudes too rapidly, which does not allow enough time for the body to adjust. Slow graded ascent to the desired altitude and termination of ascent if AMS symptoms present are keys to illness prevention. Early recognition and rapid intervention of AMS can halt progression to HACE. Pharmacologic prophylaxis with acetazolamide is a proven method of prevention and treatment of high altitude illness. If prevention fails then treatment modalities include supplemental oxygen, supportive therapy, hyperbaric treatment, and dexamethasone. Given the multitude of visitors to the mountains of Hawai‘i, high altitude illness will continue to persist as a prevalent local condition. This paper will emphasize the prevention and early diagnosis of AMS so that the illness does not progress to HACE. PMID:25478293

  13. High-Altitude Hydration System

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott E.; Orndoff, Evelyne; Bue, Grant C.; Schaefbauer, Mark E.; Urban, Kase

    2010-01-01

    Three methods are being developed for keeping water from freezing during high-altitude climbs so that mountaineers can remain hydrated. Three strategies have been developed. At the time of this reporting two needed to be tested in the field and one was conceptual. The first method is Passive Thermal Control Using Aerogels. This involves mounting the fluid reservoir of the climber s canteen to an inner layer of clothing for better heat retention. For the field test, bottles were mounted to the inner fleece layer of clothing, and then aerogel insulation was placed on the outside of the bottle, and circumferentially around the drink straw. When climbers need to drink, they can pull up the insulated straw from underneath the down suit, take a sip, and then put it back into the relative warmth of the suit. For the field test, a data logger assessed the temperatures of the water reservoir, as well as near the tip of the drink straw. The second method is Passive Thermal Control with Copper-Shielded Drink Straw and Aerogels, also mounted to inner layers of clothing for better heat retention. Braided wire emanates from the inside of the fleece jacket layer, and continues up and around the drink straw in order to use body heat to keep the system-critical drink straw warm enough to keep water in the liquid state. For the field test, a data logger will be used to compare this with the above concept. The third, and still conceptual, method is Active Thermal Control with Microcontroller. If the above methods do not work, microcontrollers and tape heaters have been identified that could keep the drink straw warm even under extremely cold conditions. Power requirements are not yet determined because the thermal environment inside the down suit relative to the external environment has not been established. A data logger will be used to track both the external and internal temperatures of the suit on a summit day.

  14. Sickness at high altitude: a literature review.

    PubMed

    Brundrett, G

    2002-03-01

    When some individuals spend just a few hours at low atmospheric pressure above 1,500 m (5,000 ft)--such as when climbing a mountain or flying in a plane at high altitude--they become ill. Altitude sickness studies originally concentrated on life-threatening illnesses which beset determined and athletic climbers at extreme altitudes. In recent years, however, research attention is moving towards milder forms of sickness reported by a significant proportion of the growing number of visitors to mountain and ski resorts at more moderate altitude. Some of this research is also relevant in understanding the problems experienced by passengers in newer planes that fly at a significantly higher equivalent cabin altitude, i.e. 2,440 m (8,000 ft), than earlier designs. Engineering solutions--such as enriched oxygen in enclosed spaces at altitude, or in the case of aircraft, lower cabin altitudes--are possible, but for an economic assessment to be realistic an engineer needs to identify the scale of the problem and to understand the factors determining susceptibility. This review concentrates on the problems of mountain sickness in the ordinary population at altitudes of around 3,000 m (10,000 ft); this is a problem of growing concern as ski resorts develop, mountain trekking increases in popularity, and as higher altitude cabin pressures are achieved in aircraft.

  15. Hyperuricemia, hypertension, and proteinuria associated with high-altitude polycythemia.

    PubMed

    Jefferson, J Ashley; Escudero, Elizabeth; Hurtado, Maria-Elena; Kelly, Jackeline Pando; Swenson, Erik R; Wener, Mark H; Burnier, Michel; Maillard, Marc; Schreiner, George F; Schoene, Robert B; Hurtado, Abdias; Johnson, Richard J

    2002-06-01

    Chronic exposure to high altitude is associated with the development of erythrocytosis, proteinuria, and, in some cases, hyperuricemia. We examined the relationship between high-altitude polycythemia and proteinuria and hyperuricemia in Cerro de Pasco, Peru (altitude, 4,300 m). We studied 25 adult men with hematocrits less than 65% and 27 subjects with excessive erythrocytosis (EE; hematocrit > 65%) living in Cerro de Pasco, Peru and compared them with 28 control subjects living in Lima, Peru (at sea level) and after 48 hours of exposure to high altitude. Serum urate levels were significantly elevated in patients with EE at altitude, and gout occurred in 4 of 27 of these subjects. Urate level strongly correlated with hematocrit (r = 0.71; P < 0.0001). Urate production (24-hour urine urate excretion and urine urate-creatinine ratio) was increased in this group compared with those at sea level. Fractional urate excretion was not increased, and fractional lithium excretion was reduced, in keeping with increased proximal reabsorption of filtrate. Significantly higher blood pressures and decreased renin levels in the EE group were in keeping with increased proximal sodium reabsorption. Serum urate levels correlated with mean blood pressure (r = 0.50; P < 0.0001). Significant proteinuria was more prevalent in the EE group despite normal renal function. Hyperuricemia is common in subjects living at high altitude and associated with EE, hypertension, and proteinuria. The increase in uric acid levels appears to be caused by increased urate generation secondary to systemic hypoxia, although a relative impairment in renal excretion also may contribute.

  16. Comparative human ventilatory adaptation to high altitude.

    PubMed

    Moore, L G

    2000-07-01

    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

  17. Respiratory control in residents at high altitude: physiology and pathophysiology.

    PubMed

    León-Velarde, Fabiola; Richalet, Jean-Paul

    2006-01-01

    Highland population (HA) from the Andes, living above 3000 m, have a blunted ventilatory response to increasing hypoxia, breathe less compared to acclimatized newcomers, but more, compared to sea-level natives at sea level. Subjects with chronic mountain sickness (CMS) breathe like sea-level natives and have excessive erythrocytosis (EE). The respiratory stimulation that arises through the peripheral chemoreflex is modestly less in the CMS group when compared with the HA group at the same P(ET(O2)). With regard to CO(2) sensitivity, CMS subjects seem to have reset their central CO(2) chemoreceptors to operate around the sea-level resting P(ET(CO2)). Acetazolamide, an acidifying drug that increases the chemosensitivity of regions in the brain stem that contain CO(2)/H(+) sensitive neurons, partially reverses this phenomenon, thus, providing CMS subjects with the possibility to have high CO(2) changes, despite small changes in ventilation. However, the same type of adjustments of the breathing pattern established for Andeans has not been found necessarily in Asian humans and/or domestic animals nor in the various high altitude species studied. The differing time frames of exposure to hypoxia among the populations, as well as the reversibility of the different components of the respiratory process at sea level, provide key concepts concerning the importance of time at high altitude in the evolution of an appropriate breathing pattern.

  18. [Acute altitude sickness and ventilatory function in subjects intermittently exposed to hypobaric hypoxia].

    PubMed

    Saldías, F; Beroíza, T; Lisboa, C

    1995-01-01

    Aiming to assess the magnitude of acute mountain sickness symptoms and ventilatory function in subjects intermittently exposed to hypobaric hypoxia, we studied 48 healthy men aged 32.6 +/- 8.2 years old who worked in a gold mine at a altitude of 4600 m, using a schedule of 8-12 days of work at the mine followed by 4 days of rest at the sea level. Studies were performed at the sea level (A), during the first two days of ascension (B) and after three or four days of stay at 4600 m (C). Mountain sickness symptoms were evaluated with a questionnaire devised in the 1991 International Hypoxia Symposium and respiratory function was assessed with a Collins Eagle II respirometer, following American Thoracic Society recommendations. Subjects reported mild to moderate symptoms during the first 24 hours of ascending (mean score of 6.4 +/- 3.1 for a maximum of 15). Forced vital capacity fell significantly in period B and returned to normal in period C and forced expiratory volume in 1 s did not change in any period. However, maximal expiratory flow and maximal midexpiratory flow rate significantly increased and remained elevated during the four days stay at the mine. No correlation was found between acute mountain sickness symptoms and changes in ventilatory function.

  19. High altitude ataxia--its assessment and relevance.

    PubMed

    Bird, Brynn A; Wright, Alexander David; Wilson, Mark H; Johnson, Brian G; Imray, Chris H

    2011-06-01

    Ataxia at altitude is reviewed in relation to acute mountain sickness (AMS). The cause of ataxia occurring at altitude is unknown but may be hypoxia affecting basal ganglia and hindbrain activity. Ataxia is an important sign of high altitude cerebral edema (HACE) but is less well-established as a clinical feature of AMS. Assessment of ataxia is part of the Environmental Systems and the Lake Louise questionnaires, together with a heel-to-toe measurement. More precise measures of ataxia include the Sharpened Romberg Test (SRT) and the use of unstable platforms. Isolated ataxia at altitude may not be related to AMS or HACE. Age affects ataxia and careful baseline measurements are essential in older subjects before results at high altitude can be interpreted. Testing for ataxia needs to be standardized with sufficient learning time. Ataxia should be distinguished from weakness or fatigue occurring at altitude. Specialized tests have not been shown to be clinically important. Our results above 5000 m showed that an abnormal SRT may be specific for AMS but with relatively poor sensitivity. Wobble board results have not correlated with AMS scores consistently. Other authors using an unstable platform in a chamber and static posturography during 3 days of exposure to 4559 m also found no relationship with AMS scores. Ataxia is a common and important clinical feature of HACE but is unhelpful in the assessment of mild or even moderate AMS in the absence of an altered mental state. The simple heel-to-toe test remains a useful part of the assessment of more severe AMS bordering on HACE.

  20. High Altitude Launch for a Practical SSTO

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Denis, Vincent

    2003-01-01

    Existing engineering materials allow the construction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. high-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2% of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated in to increased payload capability to orbit, ranging from 5 to 20% increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2% of gross lift-off weight, this corresponds to 31 % increase in payload (for 5-km launch altitude) to 122% additional payload (for 25-km launch altitude).

  1. High Altitude Launch for a Practical SSTO

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Denis, Vincent; Lyons, Valerie (Technical Monitor)

    2003-01-01

    Existing engineering materials allow the construction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. High-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2% of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated into increased payload capability to orbit, ranging from 5 to 20% increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2% of gross lift-off weight, this corresponds to 31% increase in payload (for 5-km launch altitude) to 122% additional payload (for 25-km launch altitude).

  2. High Altitude Launch for a Practical SSTO

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Denis, Vincent

    2003-01-01

    Existing engineering materials allow the construction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. High-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2 percent of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated into increased payload capability to orbit, ranging from 5 to 20 percent increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2 percent of gross lift-off weight, this corresponds to 31 percent increase in payload (for 5-kilometer launch altitude) to 122 percent additional payload (for 25-kilometer launch altitude).

  3. Transcriptomic analysis provides insight into high-altitude acclimation in domestic goats.

    PubMed

    Tang, Qianzi; Huang, Wenyao; Guan, Jiuqiang; Jin, Long; Che, Tiandong; Fu, Yuhua; Hu, Yaodong; Tian, Shilin; Wang, Dawei; Jiang, Zhi; Li, Xuewei; Li, Mingzhou

    2015-08-10

    Domestic goats are distributed in a wide range of habitats and have acclimated to their local environmental conditions. To investigate the gene expression changes of goats that are induced by high altitude stress, we performed RNA-seq on 27 samples from the three hypoxia-sensitive tissues (heart, lung, and skeletal muscle) in three indigenous populations from distinct altitudes (600 m, 2000 m, and 3000 m). We generated 129Gb of high-quality sequencing data (~4Gb per sample) and catalogued the expression profiles of 12,421 annotated hircine genes in each sample. The analysis showed global similarities and differences of high-altitude transcriptomes among populations and tissues as well as revealed that the heart underwent the most high-altitude induced expression changes. We identified numerous differentially expressed genes that exhibited distinct expression patterns, and nonsynonymous single nucleotide variant-containing genes that were highly differentiated between the high- and low-altitude populations. These genes have known or potential roles in hypoxia response and were enriched in functional gene categories potentially responsible for high-altitude stress. Therefore, they are appealing candidates for further investigation of the gene expression and associated regulatory mechanisms related to high-altitude acclimation.

  4. [Human life at high altitudes: myths and realities].

    PubMed

    Vargas, E; Villena, M

    1989-01-01

    Life at high altitude presents very interesting biological and medical aspects. For countries such as the Andeans, it also has socio-economical implications. The most important towns of Bolivia are situated between 3,000 and 4,850 m. It's to say that a great percentage of the population is permanently staying there. Moreover owing to the improvement of the roads and transport, an extensive migration (professional life, business, tourism, sport) developed some years ago. At 3,000 to 4,850 m, an oxygen arterial pressure (PaO2) between 40 and 70 mm Hg is resulting from the environmental hypoxia. The adaptation to hypoxia takes place in two phases: --that incomplete, observed at short time in people who recently arrived, --that at very long time, observed in the native. The rapid arrival at more than 3,000 m, exposes the traveller to an hypoxic ventilatory stimulus which produces a hyperventilation response to increased PaO2. This hyperventilation brings out a decreasing of carbon dioxide arterial pressure (PaCO2) and alkalosis of the blood. This respiratory alkalosis seems to be responsible for most troubles which are present in the Acute Mountain Sickness linked to the CO2 role in cerebral blood circulation. At the same time but more slowly the classical high altitude polycythemia develops which permits compensate partially the hypoxic effect in 3 to 4 weeks. In the native the adaptation implies physiological variations of some parameters concerning the individual development. The principal studies showed that the native present a notable hyposensitivity to hypoxia and also to the stimulus CO2-H+. The Chronic Mountain Sickness patients have a less sensitivity to the same stimuli than the natives.

  5. Impact of extreme exercise at high altitude on oxidative stress in humans.

    PubMed

    Quindry, John; Dumke, Charles; Slivka, Dustin; Ruby, Brent

    2016-09-15

    Exercise and oxidative stress research continues to grow as a physiological subdiscipline. The influence of high altitude on exercise and oxidative stress is among the recent topics of intense study in this area. Early findings indicate that exercise at high altitude has an independent influence on free radical generation and the resultant oxidative stress. This review provides a detailed summary of oxidative stress biochemistry as gleaned mainly from studies of humans exercising at high altitude. Understanding of the human response to exercise at altitude is largely derived from field-based research at altitudes above 3000 m in addition to laboratory studies which employ normobaric hypoxia. The implications of oxidative stress incurred during high altitude exercise appear to be a transient increase in oxidative damage followed by redox-sensitive adaptations in multiple tissues. These outcomes are consistent for lowland natives, high altitude acclimated sojourners and highland natives, although the latter group exhibits a more robust adaptive response. To date there is no evidence that altitude-induced oxidative stress is deleterious to normal training or recovery scenarios. Limited evidence suggests that deleterious outcomes related to oxidative stress are limited to instances where individuals are exposed to extreme elevations for extended durations. However, confirmation of this tentative conclusion requires further investigation. More applicably, altitude-induced hypoxia may have an independent influence on redox-sensitive adaptive responses to exercise and exercise recovery. If correct, these findings may hold important implications for athletes, mountaineers, and soldiers working at high altitude. These points are raised within the confines of published research on the topic of oxidative stress during exercise at altitude.

  6. Endogenous Asymmetric Dimethylarginine Pathway in High Altitude Adapted Yaks

    PubMed Central

    Mizuno, Shiro; Ishizaki, Takeshi; Toga, Hirohisa; Sakai, Akio; Isakova, Jainagul; Taalaibekova, Elnura; Baiserkeev, Zamirbek; Kojonazarov, Baktybek; Aldashev, Almaz

    2015-01-01

    Hypoxia-induced and high altitude pulmonary hypertension are a major problem in the mountain areas of the world. The asymmetric methylarginines (ADMA) inhibit nitric oxide (NO) synthesis by competing with L-arginine, and high levels of plasma ADMA predict adverse outcomes in pulmonary hypertension. However, little is known about the regulation of the ADMA-NO pathway in animals adapted to high altitudes. We measured the plasma ADMA concentration, endothelial NO synthase (eNOS), dimethylarginine dimethylaminohydrolases (DDAH) protein expression, and DDAH activities in the lungs from yaks. Although the yaks are hypoxemic, cardiac function and pulmonary arterial pressures are almost normal, and we found decreased DDAH expression and activity in association with reduced plasma ADMA concentrations. The eNOS expression was significantly higher in yaks. These results indicate that augmented endogenous NO activity in yaks through the ADMA-DDAH pathway and eNOS upregulation account for the low pulmonary vascular tone observed in high altitude adapted yaks. PMID:26380264

  7. Verbal free recall in high altitude: proper names vs common names.

    PubMed

    Pelamatti, Giovanna; Pascotto, Milena; Semenza, Carlo

    2003-02-01

    Exposure to extreme altitude is known to cause a general impairment of cognitive functions. In this study we investigated the effect of high altitude on the recall of supraspan lists of proper and common names. High altitude seems to have a dramatic effect on the recall of proper names, while common names are more resistant to hypoxia. This effect, however, seems to selectively concern the early items of the lists. This damage to the primacy effect in proper name recall seems permanent over time. The absence of damage in recalling names from the last serial position clearly shows how STM functions are relatively more resistant to the lack of cognitive sources caused by hypoxia.

  8. Stunting and the Prediction of Lung Volumes Among Tibetan Children and Adolescents at High Altitude.

    PubMed

    Weitz, Charles A; Garruto, Ralph M

    2015-12-01

    This study examines the extent to which stunting (height-for-age Z-scores ≤ -2) compromises the use of low altitude prediction equations to gauge the general increase in lung volumes during growth among high altitude populations. The forced vital capacity (FVC) and forced expiratory volume (FEV1) of 208 stunted and 365 non-stunted high-altitude Tibetan children and adolescents between the ages of 6 and 20 years are predicted using the Third National Health and Nutrition Examination Survey (NHANESIII) and the Global Lung Function Initiative (GLF) equations, and compared to observed lung volumes. Stunted Tibetan children show smaller positive deviations from both NHANESIII and GLF prediction equations at most ages than non-stunted children. Deviations from predictions do not correspond to differences in body proportions (sitting heights and chest circumferences relative to stature) between stunted and non-stunted children; but appear compatible with the effects of retarded growth and lung maturation that are likely to exist among stunted children. These results indicate that, before low altitude standards can be used to evaluate the effects of hypoxia, or before high altitude populations can be compared to any other group, it is necessary to assess the relative proportion of stunted children in the samples. If the proportion of stunted children in a high altitude population differs significantly from the proportion in the comparison group, lung function comparisons are unlikely to yield an accurate assessment of the hypoxia effect. The best solution to this problem is to (1) use stature and lung function standards based on the same low altitude population; and (2) assess the hypoxic effect by comparing observed and predicted values among high altitude children whose statures are most like those of children on whom the low altitude spirometric standard is based-preferably high altitude children with HAZ-scores ≥ -1.

  9. COPD and air travel: does hypoxia-altitude simulation testing predict in-flight respiratory symptoms?

    PubMed

    Edvardsen, Anne; Ryg, Morten; Akerø, Aina; Christensen, Carl Christian; Skjønsberg, Ole H

    2013-11-01

    The reduced pressure in an aircraft cabin may cause significant hypoxaemia and respiratory symptoms in patients with chronic obstructive pulmonary disease (COPD). The current study evaluated whether there is a relationship between hypoxaemia obtained during hypoxia-altitude simulation testing (HAST), simulating an altitude of 2438 m, and the reporting of respiratory symptoms during air travel. 82 patients with moderate to very severe COPD answered an air travel questionnaire. Arterial oxygen tensions during HAST (PaO2HAST) in subjects with and without in-flight respiratory symptoms were compared. The same questionnaire was answered within 1 year after the HAST. Mean ± sd PaO2HAST was 6.3 ± 0.6 kPa and 62 (76%) of the patients had PaO2HAST <6.6 kPa. 38 (46%) patients had experienced respiratory symptoms during air travel. There was no difference in PaO2HAST in those with and those without in-flight respiratory symptoms (6.3 ± 0.7 kPa versus 6.3 ± 0.6 kPa, respectively; p=0.926). 54 (66%) patients travelled by air after the HAST, and patients equipped with supplemental oxygen (n = 23, 43%) reported less respiratory symptoms when flying with than those without such treatment (four (17%) versus 11 (48%) patients; p=0.039). In conclusion, no difference in PaO2HAST was found between COPD patients with and without respiratory symptoms during air travel. PMID:23258777

  10. COPD and air travel: does hypoxia-altitude simulation testing predict in-flight respiratory symptoms?

    PubMed

    Edvardsen, Anne; Ryg, Morten; Akerø, Aina; Christensen, Carl Christian; Skjønsberg, Ole H

    2013-11-01

    The reduced pressure in an aircraft cabin may cause significant hypoxaemia and respiratory symptoms in patients with chronic obstructive pulmonary disease (COPD). The current study evaluated whether there is a relationship between hypoxaemia obtained during hypoxia-altitude simulation testing (HAST), simulating an altitude of 2438 m, and the reporting of respiratory symptoms during air travel. 82 patients with moderate to very severe COPD answered an air travel questionnaire. Arterial oxygen tensions during HAST (PaO2HAST) in subjects with and without in-flight respiratory symptoms were compared. The same questionnaire was answered within 1 year after the HAST. Mean ± sd PaO2HAST was 6.3 ± 0.6 kPa and 62 (76%) of the patients had PaO2HAST <6.6 kPa. 38 (46%) patients had experienced respiratory symptoms during air travel. There was no difference in PaO2HAST in those with and those without in-flight respiratory symptoms (6.3 ± 0.7 kPa versus 6.3 ± 0.6 kPa, respectively; p=0.926). 54 (66%) patients travelled by air after the HAST, and patients equipped with supplemental oxygen (n = 23, 43%) reported less respiratory symptoms when flying with than those without such treatment (four (17%) versus 11 (48%) patients; p=0.039). In conclusion, no difference in PaO2HAST was found between COPD patients with and without respiratory symptoms during air travel.

  11. [Health status of high-altitude population].

    PubMed

    Okumiya, Kiyoto

    2013-01-01

    The health status of high-altitude population in Qinghai (China), Ladakh (India), and Arunachal (India) was investigated using comprehensive geriatric functional assessment in relation to their recent lifestyle change with the socio-economic globalization. People in urban areas had a higher prevalence of lifestyle-related diseases and poorer geriatric functions, and a lower subjective quality of life (QOL) than people in rural areas. The optimal prevention of lifestyle-related diseases and preservation of a high QOL are important for the people living in each of the above-mentioned areas with a high altitude.

  12. Control of respiration in flight muscle from the high-altitude bar-headed goose and low-altitude birds.

    PubMed

    Scott, Graham R; Richards, Jeffrey G; Milsom, William K

    2009-10-01

    Bar-headed geese fly at altitudes of up to 9,000 m on their biannual migration over the Himalayas. To determine whether the flight muscle of this species has evolved to facilitate exercise at high altitude, we compared the respiratory properties of permeabilized muscle fibers from bar-headed geese and several low-altitude waterfowl species. Respiratory capacities were assessed for maximal ADP stimulation (with single or multiple inputs to the electron transport system) and cytochrome oxidase excess capacity (with an exogenous electron donor) and were generally 20-40% higher in bar-headed geese when creatine was present. When respiration rates were extrapolated to the entire pectoral muscle mass, bar-headed geese had a higher mass-specific aerobic capacity. This may represent a surplus capacity that counteracts the depressive effects of hypoxia on mitochondrial respiration. However, there were no differences in activity for mitochondrial or glycolytic enzymes measured in homogenized muscle. The [ADP] leading to half-maximal stimulation (K(m)) was approximately twofold higher in bar-headed geese (10 vs. 4-6 microM), and, while creatine reduced K(m) by 30% in this species, it had no effect on K(m) in low-altitude birds. Mitochondrial creatine kinase may therefore contribute to the regulation of oxidative phosphorylation in flight muscle of bar-headed geese, which could promote efficient coupling of ATP supply and demand. However, this was not based on differences in creatine kinase activity in isolated mitochondria or homogenized muscle. The unique differences in bar-headed geese existed without prior exercise or hypoxia exposure and were not a result of phylogenetic history, and may, therefore, be important evolutionary specializations for high-altitude flight.

  13. Sonic Thermometer for High-Altitude Balloons

    NASA Technical Reports Server (NTRS)

    Bognar, John

    2012-01-01

    The sonic thermometer is a specialized application of well-known sonic anemometer technology. Adaptations have been made to the circuit, including the addition of supporting sensors, which enable its use in the high-altitude environment and in non-air gas mixtures. There is a need to measure gas temperatures inside and outside of superpressure balloons that are flown at high altitudes. These measurements will allow the performance of the balloon to be modeled more accurately, leading to better flight performance. Small thermistors (solid-state temperature sensors) have been used for this general purpose, and for temperature measurements on radiosondes. A disadvantage to thermistors and other physical (as distinct from sonic) temperature sensors is that they are subject to solar heating errors when they are exposed to the Sun, and this leads to issues with their use in a very high-altitude environment

  14. Iron supplementation at high altitudes induces inflammation and oxidative injury to lung tissues in rats

    SciTech Connect

    Salama, Samir A.; Omar, Hany A.; Maghrabi, Ibrahim A.; AlSaeed, Mohammed S.; EL-Tarras, Adel E.

    2014-01-01

    Exposure to high altitudes is associated with hypoxia and increased vulnerability to oxidative stress. Polycythemia (increased number of circulating erythrocytes) develops to compensate the high altitude associated hypoxia. Iron supplementation is, thus, recommended to meet the demand for the physiological polycythemia. Iron is a major player in redox reactions and may exacerbate the high altitudes-associated oxidative stress. The aim of this study was to explore the potential iron-induced oxidative lung tissue injury in rats at high altitudes (6000 ft above the sea level). Iron supplementation (2 mg elemental iron/kg, once daily for 15 days) induced histopathological changes to lung tissues that include severe congestion, dilatation of the blood vessels, emphysema in the air alveoli, and peribronchial inflammatory cell infiltration. The levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), lipid peroxidation product and protein carbonyl content in lung tissues were significantly elevated. Moreover, the levels of reduced glutathione and total antioxidant capacity were significantly reduced. Co-administration of trolox, a water soluble vitamin E analog (25 mg/kg, once daily for the last 7 days of iron supplementation), alleviated the lung histological impairments, significantly decreased the pro-inflammatory cytokines, and restored the oxidative stress markers. Together, our findings indicate that iron supplementation at high altitudes induces lung tissue injury in rats. This injury could be mediated through excessive production of reactive oxygen species and induction of inflammatory responses. The study highlights the tissue injury induced by iron supplementation at high altitudes and suggests the co-administration of antioxidants such as trolox as protective measures. - Highlights: • Iron supplementation at high altitudes induced lung histological changes in rats. • Iron induced oxidative stress in lung tissues of rats at high altitudes. • Iron

  15. Total antioxidant status at high altitude in lowlanders and native highlanders: role of uric acid.

    PubMed

    Sinha, Sanchari; Singh, Som Nath; Ray, Uday Sankar

    2009-01-01

    Hypobaric hypoxia causes oxidative stress and the antioxidant system of the body plays a vital role in controlling it. Urate contributes up to two-thirds of the antioxidant capacity of human blood. The urate production is catalyzed by xanthine oxidase with a concomitant release of free radicals. This study was designed to appraise the role of urate as an antioxidant at high altitude. The study was conducted on 92 male lowlanders and 66 highlanders after ascent to high altitude at 4560 m. Blood was collected at sea level and after 4 weeks of high altitude exposure. In lowlanders, a significant increase in levels of hydroperoxide (551.4 +/- 4.2 micromol/mL vs. 582.0 +/- 3.55, p < 0.001], protein carbonyl (2.4 +/- 0.11 micromol/mL/mg protein vs. 3.03 +/- 0.11, p < 0.001), TAS (1.02 +/- 0.01 mmol/L vs. 1.19 +/- 0.02, p < 0.001), and UA (298.0 +/- 6.68 micromol/L vs. 383.0 +/- 6.55, p < 0.001) was observed at high altitude. These measurements were significantly lower in highlanders than in lowlanders at high altitude. Total antioxidant status (TAS) and uric acid (UA) showed a positive correlation in lowlanders at sea level and in highlanders at high altitude. Hydroperoxide and TAS also showed a positive correlation in both groups at high altitude. This indicates increased oxidative stress at high altitude despite an increase in antioxidant capacity in lowlanders. To conclude, a hypoxia-induced increase in UA contributes an appreciable portion of plasma total antioxidant capacity, but may not be effective in preventing oxidative stress at high altitude. PMID:19775217

  16. Remote ischemic preconditioning for prevention of high-altitude diseases: fact or fiction?

    PubMed

    Berger, Marc Moritz; Macholz, Franziska; Mairbäurl, Heimo; Bärtsch, Peter

    2015-11-15

    Preconditioning refers to exposure to brief episodes of potentially adverse stimuli and protects against injury during subsequent exposures. This was first described in the heart, where episodes of ischemia/reperfusion render the myocardium resistant to subsequent ischemic injury, which is likely caused by reactive oxygen species (ROS) and proinflammatory processes. Protection of the heart was also found when preconditioning was performed in an organ different from the target, which is called remote ischemic preconditioning (RIPC). The mechanisms causing protection seem to include stimulation of nitric oxide (NO) synthase, increase in antioxidant enzymes, and downregulation of proinflammatory cytokines. These pathways are also thought to play a role in high-altitude diseases: high-altitude pulmonary edema (HAPE) is associated with decreased bioavailability of NO and increased generation of ROS, whereas mechanisms causing acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) seem to involve cytotoxic effects by ROS and inflammation. Based on these apparent similarities between ischemic damage and AMS, HACE, and HAPE, it is reasonable to assume that RIPC might be protective and improve altitude tolerance. In studies addressing high-altitude/hypoxia tolerance, RIPC has been shown to decrease pulmonary arterial systolic pressure in normobaric hypoxia (13% O2) and at high altitude (4,342 m). Our own results indicate that RIPC transiently decreases the severity of AMS at 12% O2. Thus preliminary studies show some benefit, but clearly, further experiments to establish the efficacy and potential mechanism of RIPC are needed.

  17. Wind study for high altitude platform design

    NASA Technical Reports Server (NTRS)

    Strganac, T. W.

    1979-01-01

    An analysis of upper air winds was performed to define the wind environment at potential operating altitudes for high-altitude powered platform concepts. Expected wind conditions of the contiguous United States, Pacific area (Alaska to Sea of Japan), and European area (Norwegian and Mediterranean Seas) were obtained using a representative network of sites selected based upon adequate high-altitude sampling, geographic dispersion, and observed upper wind patterns. A data base of twenty plus years of rawinsonde gathered wind information was used in the analysis. Annual variations from surface to 10 mb (approximately 31 km) pressure altitude were investigated to encompass the practical operating range for the platform concepts. Parametric analysis for the United States and foreign areas was performed to provide a basis for vehicle system design tradeoffs. This analysis of wind magnitudes indicates the feasibility of annual operation at a majority of sites and more selective seasonal operation for the extreme conditions between the pressure altitudes of 100 to 25 mb based upon the assumed design speeds.

  18. Wind study for high altitude platform design

    NASA Technical Reports Server (NTRS)

    Strganac, T. W.

    1979-01-01

    An analysis of upper air winds was performed to define the wind environment at potential operating altitudes for high altitude powered platform concepts. Wind conditions of the continental United States, Pacific area (Alaska to Sea of Japan), and European area (Norwegian and Mediterranean Sea) were obtained using a representative network of sites selected based upon adequate high altitude sampling, geographic dispersion, and observed upper wind patterns. A data base of twenty plus years of rawinsonde gathered wind information was used in the analysis. Annual variations from surface to 10 mb pressure altitude were investigated to encompass the practical operating range for the platform concepts. Parametric analysis for the United States and foreign areas was performed to provide a basis for vehicle system design tradeoffs. This analysis of wind magnitudes indicates the feasibility of annual operation at a majority of sites and more selective seasonal operation for the extreme conditions between the pressure altitudes of 100 to 25 mb based upon the assumed design speeds.

  19. Sleep of Andean high altitude natives.

    PubMed

    Coote, J H; Stone, B M; Tsang, G

    1992-01-01

    The structure of sleep in lowland visitors to altitudes greater than 4000 m is grossly disturbed. There are no data on sleep in long-term residents of high altitudes. This paper describes an electroencephalographic study of sleep in high altitude dwellers who were born in and are permanent residents of Cerro de Pasco in the Peruvian Andes, situated at 4330 m. Eight healthy male volunteers aged between 18 and 69 years were studied. Sleep was measured on three consecutive nights for each subject. Electroencephalographs, submental electromyographs and electro-oculograms were recorded. Only data from the third night were used in the analysis. The sleep patterns of these subjects resembled the normal sleep patterns described by others in lowlanders at sea level. There were significant amounts of slow wave sleep in the younger subjects and rapid eye movement sleep seemed unimpaired.

  20. Elevated performance: the unique physiology of birds that fly at high altitudes.

    PubMed

    Scott, Graham R

    2011-08-01

    Birds that fly at high altitudes must support vigorous exercise in oxygen-thin environments. Here I discuss the characteristics that help high fliers sustain the high rates of metabolism needed for flight at elevation. Many traits in the O(2) transport pathway distinguish birds in general from other vertebrates. These include enhanced gas-exchange efficiency in the lungs, maintenance of O(2) delivery and oxygenation in the brain during hypoxia, augmented O(2) diffusion capacity in peripheral tissues and a high aerobic capacity. These traits are not high-altitude adaptations, because they are also characteristic of lowland birds, but are nonetheless important for hypoxia tolerance and exercise capacity. However, unique specializations also appear to have arisen, presumably by high-altitude adaptation, at every step in the O(2) pathway of highland species. The distinctive features of high fliers include an enhanced hypoxic ventilatory response, an effective breathing pattern, larger lungs, haemoglobin with a higher O(2) affinity, further augmentation of O(2) diffusion capacity in the periphery and multiple alterations in the metabolic properties of cardiac and skeletal muscle. These unique specializations improve the uptake, circulation and efficient utilization of O(2) during high-altitude hypoxia. High-altitude birds also have larger wings than their lowland relatives to reduce the metabolic costs of staying aloft in low-density air. High fliers are therefore unique in many ways, but the relative roles of adaptation and plasticity (acclimatization) in high-altitude flight are still unclear. Disentangling these roles will be instrumental if we are to understand the physiological basis of altitudinal range limits and how they might shift in response to climate change.

  1. High Altitude Synthetic Aperture Imaging of Titan

    NASA Astrophysics Data System (ADS)

    West, Richard; Stiles, B.; Anderson, Y.; Boehmer, R.; Callahan, P.; Gim, Y.; Hamilton, G.; Johnson, W. T.; Kelleher, K.; Wye, L.; Zebker, H.

    2006-09-01

    The Cassini spacecraft has been conducting observations of Titan since July 2004 . Currently, 6 close flyby's have collected synthetic aperture radar (SAR) data giving image resolutions down to 300 - 500 m. About 14 additional close radar imaging passes are planned. To improve radar coverage and increase the synergy with other Cassini imaging instruments such as VIMS and ISS, the radar team has started experimenting with very high altitude SAR imaging where conditions permit. This presentation will examine the performance trade-offs, special processing issues, and science potential of these high altitude SAR observations. These data collections are distinct from the normal Titan SAR images because the range will be much larger (around 20,000 km). To acquire enough signal in these circumstances, the radar operates in the lowest bandwidth scatterometer mode while spacecraft pointing control is used to slowly pan the central beam across a small swath. Due to a lower signal to noise ratio these high altitude images are designed to average together 150-200 independent looks to see features that may lie below the noise floor. So far, three high altitude images have been acquired during Titan flyby's T12, T13, and T15. In T12 imaging was attempted from 37000 km with an effective resolution around 5 km. In T13 the Huygens Probe landing site was imaged from 11000 km with effective resolution of 1 - 2 km. In T15 the Tsegehi area was imaged from 20000 km with effective resolution of 2 - 3 km.

  2. The physiological effects of resveratrol and its potential application in high altitude medicine.

    PubMed

    Zhu, Hui-li; Nie, Hong-jing; Li, Pei-bing; Deng, Bing-nan; Duan, Rui-feng; Jin, Hong; Chen, Zhao-li

    2015-11-01

    Resveratrol, as a natural polyphenolic compound, has a wide range of beneficial effects, which includes anti-tumor, cardiovascular protection, anti-oxidant and estrogen-like effects, and so on. Its various physiological properties are closely related to the therapeutic principle for prevention and treatment of high altitude hypoxia injury. Resveratrol may play an important role in relieving or curing high altitude diseases, especially high altitude polycythemia(HAPC). However, the literature about study and application of resveratrol in plateau medicine field is rarely reported up to now. In this review, we summarized the physiological effects of resveratrol, discussed the possible main principle of resveratrol for HAPC therapy, and looked forward to resveratrol's perspective or potential application in high altitude medicine.

  3. High-altitude physiology: lessons from Tibet

    NASA Astrophysics Data System (ADS)

    Wagner, Peter D.; Simonson, Tatum S.; Wei, Guan; Wagner, Harrieth; Wuren, Tanna; Yan, Ma; Qin, Ga; Ge, Rili

    2013-05-01

    Polycythemia is a universal lowlander response to altitude; healthy Andean high-altitude natives also have elevated [Hb]. While this may enhance O2 transport to tissues, studies have shown that acute isovolumic changes in [Hb] do not affect exercise capacity. Many high-altitude Tibetans have evolved sea-level values of [Hb], providing a natural opportunity to study this issue. In 21 young healthy male Tibetans with [Hb] between 15 and 23 g/dl, we measured VO2MAX and O2 transport capacity at 4200m. VO2MAX was higher when [Hb] was lower (P<0.05), enabled by both higher cardiac output and muscle O2 diffusional conductance, but neither ventilation nor the alveolar-arterial PO2 difference (AaPO2) varied with [Hb]. In contrast, Andean high altitude natives remain polycythemic with larger lungs and higher lung diffusing capacity, a smaller exercising AaPO2, and lower ventilation. The challenges now are (1) to understand the different adaptive pathways used by Andeans and Tibetans, and (2) to determine in Tibetans whether, during evolution, reduced [Hb] appeared first, causing compensatory cardiac and muscle adaptations, or if enhanced cardiac function and muscle O2 transport capacity appeared first, permitting secondary reduction in [Hb]. For (2), further research is necessary to determine the basis of enhanced cardiac function and muscle O2 transport, and identify molecular targets of evolution in heart and muscle. Putative mutations can then be timed and compared to appearance of those affecting [Hb].

  4. Estimation of high altitude Martian dust parameters

    NASA Astrophysics Data System (ADS)

    Pabari, Jayesh; Bhalodi, Pinali

    2016-07-01

    Dust devils are known to occur near the Martian surface mostly during the mid of Southern hemisphere summer and they play vital role in deciding background dust opacity in the atmosphere. The second source of high altitude Martian dust could be due to the secondary ejecta caused by impacts on Martian Moons, Phobos and Deimos. Also, the surfaces of the Moons are charged positively due to ultraviolet rays from the Sun and negatively due to space plasma currents. Such surface charging may cause fine grains to be levitated, which can easily escape the Moons. It is expected that the escaping dust form dust rings within the orbits of the Moons and therefore also around the Mars. One more possible source of high altitude Martian dust is interplanetary in nature. Due to continuous supply of the dust from various sources and also due to a kind of feedback mechanism existing between the ring or tori and the sources, the dust rings or tori can sustain over a period of time. Recently, very high altitude dust at about 1000 km has been found by MAVEN mission and it is expected that the dust may be concentrated at about 150 to 500 km. However, it is mystery how dust has reached to such high altitudes. Estimation of dust parameters before-hand is necessary to design an instrument for the detection of high altitude Martian dust from a future orbiter. In this work, we have studied the dust supply rate responsible primarily for the formation of dust ring or tori, the life time of dust particles around the Mars, the dust number density as well as the effect of solar radiation pressure and Martian oblateness on dust dynamics. The results presented in this paper may be useful to space scientists for understanding the scenario and designing an orbiter based instrument to measure the dust surrounding the Mars for solving the mystery. The further work is underway.

  5. High Altitude Plasma Instrument (HAPI) data analysis

    NASA Technical Reports Server (NTRS)

    Burch, J. L.

    1994-01-01

    The objectives of the Dynamics Explorer mission are to investigate the coupling of energy, mass, and momentum among the earth's magnetosphere, ionosphere, and upper atmosphere. At launch, on August 3, 1981, DE-1 was placed into an elliptical polar orbit having an apogee of 23,130 km to allow global auroral imaging and crossings of auroral field lines at altitudes of several thousand kilometers. At the same time DE-2 was placed into a polar orbit, coplanar with that of DE-1 but with a perigee altitude low enough (309 km) for neutral measurements and an apogee altitude of 1012 km. The DE-1 High Altitude Plasma Instrument (HAPI) provided data on low and medium energy electrons and ions from August 13, 1981 until December 1, 1981, when a high-voltage failure occured. Analysis of HAPI data for the time period of this contract has produced new results on the source mechanisms for electron conical distributions, particle acceleration phenomena in auroral acceleration regions, Birkeland currents throughout the nightside auroral regions, the source region for auroral kilometric radiation (AKR), and plasma injection phenomena in the polar cusp.

  6. Teaching the Physiology of Adaptation to Hypoxic Stress with the Aid of a Classic Paper on High Altitude by Houston and Riley

    ERIC Educational Resources Information Center

    Tansey, Etain A.

    2008-01-01

    Many pathological conditions exist where tissues exhibit hypoxia or low oxygen tension. Hypoxic hypoxia arises when there is a reduction in the amount of oxygen entering the blood and occurs in healthy people at high altitude. In 1946, research sponsored by the United States Navy led to the collection and subsequent publication of masses of data…

  7. High-altitude solar power platform

    SciTech Connect

    Bailey, M.D.; Bower, M.V.

    1992-04-01

    Solar power is a preeminent alternative to conventional aircraft propulsion. With the continued advances in solar cells, fuel cells, and composite materials technology, the solar powered airplane is no longer a simple curiosity constrained to flights of several feet in altitude or minutes of duration. A high altitude solar powered platform (HASPP) has several potential missions, including communications and agriculture. In remote areas, a HASPP could be used as a communication link. In large farming areas, a HASPP could perform remote sensing of crops. The impact of HASPP in continuous flight for one year on agricultural monitoring mission is presented. This mission provides farmers with near real-time data twice daily from an altitude which allows excellant resolution on water conditions, crop diseases, and insect infestation. Accurate, timely data will enable farmers to increase their yield and efficiency. A design for HASPP for the foregoing mission is presented. In the design power derived from solar cells covering the wings is used for propulsion, avionics, and sensors. Excess power produced midday will be stored in fuel cells for use at night to maintain altitude and course.

  8. Metabolic insight into mechanisms of high-altitude adaptation in Tibetans.

    PubMed

    Ge, Ri-Li; Simonson, Tatum S; Cooksey, Robert C; Tanna, Uran; Qin, Ga; Huff, Chad D; Witherspoon, David J; Xing, Jinchuan; Zhengzhong, Bai; Prchal, Josef T; Jorde, Lynn B; McClain, Donald A

    2012-06-01

    Recent studies have identified genes involved in high-altitude adaptation in Tibetans. Genetic variants/haplotypes within regions containing three of these genes (EPAS1, EGLN1, and PPARA) are associated with relatively decreased hemoglobin levels observed in Tibetans at high altitude, providing corroborative evidence for genetic adaptation to this extreme environment. The mechanisms that afford adaptation to high-altitude hypoxia, however, remain unclear. Considering the strong metabolic demands imposed by hypoxia, we hypothesized that a shift in fuel preference to glucose oxidation and glycolysis at the expense of fatty acid oxidation would improve adaptation to decreased oxygen availability. Correlations between serum free fatty acid and lactate concentrations in Tibetan groups living at high altitude and putatively selected haplotypes provide insight into this hypothesis. An EPAS1 haplotype that exhibits a signal of positive selection is significantly associated with increased lactate concentration, the product of anaerobic glycolysis. Furthermore, the putatively advantageous PPARA haplotype is correlated with serum free fatty acid concentrations, suggesting a possible decrease in the activity of fatty acid oxidation. Although further studies are required to assess the molecular mechanisms underlying these patterns, these associations suggest that genetic adaptation to high altitude involves alteration in energy utilization pathways.

  9. Identifying positive selection candidate loci for high-altitude adaptation in Andean populations

    PubMed Central

    2009-01-01

    High-altitude environments (>2,500 m) provide scientists with a natural laboratory to study the physiological and genetic effects of low ambient oxygen tension on human populations. One approach to understanding how life at high altitude has affected human metabolism is to survey genome-wide datasets for signatures of natural selection. In this work, we report on a study to identify selection-nominated candidate genes involved in adaptation to hypoxia in one highland group, Andeans from the South American Altiplano. We analysed dense microarray genotype data using four test statistics that detect departures from neutrality. Using a candidate gene, single nucleotide polymorphism-based approach, we identified genes exhibiting preliminary evidence of recent genetic adaptation in this population. These included genes that are part of the hypoxia-inducible transcription factor (HIF) pathway, a biochemical pathway involved in oxygen homeostasis, as well as three other genomic regions previously not known to be associated with high-altitude phenotypes. In addition to identifying selection-nominated candidate genes, we also tested whether the HIF pathway shows evidence of natural selection. Our results indicate that the genes of this biochemical pathway as a group show no evidence of having evolved in response to hypoxia in Andeans. Results from particular HIF-targeted genes, however, suggest that genes in this pathway could play a role in Andean adaptation to high altitude, even if the pathway as a whole does not show higher relative rates of evolution. These data suggest a genetic role in high-altitude adaptation and provide a basis for genotype/phenotype association studies that are necessary to confirm the role of putative natural selection candidate genes and gene regions in adaptation to altitude. PMID:20038496

  10. Mitochondrial function at extreme high altitude.

    PubMed

    Murray, Andrew J; Horscroft, James A

    2016-03-01

    At high altitude, barometric pressure falls and with it inspired P(O2), potentially compromising O2 delivery to the tissues. With sufficient acclimatisation, the erythropoietic response increases red cell mass such that arterial O2 content (C(aO2)) is restored; however arterial P(O2)(P(aO2)) remains low, and the diffusion of O2 from capillary to mitochondrion is impaired. Mitochondrial respiration and aerobic capacity are thus limited, whilst reactive oxygen species (ROS) production increases. Restoration of P(aO2) with supplementary O2 does not fully restore aerobic capacity in acclimatised individuals, possibly indicating a peripheral impairment. With prolonged exposure to extreme high altitude (>5500 m), muscle mitochondrial volume density falls, with a particular loss of the subsarcolemmal population. It is not clear whether this represents acclimatisation or deterioration, but it does appear to be regulated, with levels of the mitochondrial biogenesis factor PGC-1α falling, and shows similarities to adapted Tibetan highlanders. Qualitative changes in mitochondrial function also occur, and do so at more moderate high altitudes with shorter periods of exposure. Electron transport chain complexes are downregulated, possibly mitigating the increase in ROS production. Fatty acid oxidation capacity is decreased and there may be improvements in biochemical coupling at the mitochondrial inner membrane that enhance O2 efficiency. Creatine kinase expression falls, possibly impairing high-energy phosphate transfer from the mitochondria to myofibrils. In climbers returning from the summit of Everest, cardiac energetic reserve (phosphocreatine/ATP) falls, but skeletal muscle energetics are well preserved, possibly supporting the notion that mitochondrial remodelling is a core feature of acclimatisation to extreme high altitude. PMID:26033622

  11. Solar radiation monitoring for high altitude aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.

    1981-01-01

    Ground-based and satellite-based ionizing radiation monitoring systems are considered as alternative methods for ensuring safe radiation levels for high-altitude aircraft. It is found that ground-based methods are of limited accuracy due to insensitivity to solar particles of energies between the riometer upper cutoff of about 50 MeV and the neutron monitor threshold of about 450 MeV. This energy range is demonstrated to be essential for atmospheric radiation monitoring at high altitude, and must be covered by satellite measurement. On the basis of presently available data, the accuracy to which the incident solar particle flux must be measured by satellite-borne detectors is examined and recommendations are made to establish minimum requirements.

  12. Solar radiation monitoring for high altitude aircraft

    NASA Astrophysics Data System (ADS)

    Wilson, J. W.

    1981-10-01

    Ground-based and satellite-based ionizing radiation monitoring systems are considered as alternative methods for ensuring safe radiation levels for high-altitude aircraft. It is found that ground-based methods are of limited accuracy due to insensitivity to solar particles of energies between the riometer upper cutoff of about 50 MeV and the neutron monitor threshold of about 450 MeV. This energy range is demonstrated to be essential for atmospheric radiation monitoring at high altitude, and must be covered by satellite measurement. On the basis of presently available data, the accuracy to which the incident solar particle flux must be measured by satellite-borne detectors is examined and recommendations are made to establish minimum requirements.

  13. Is High Altitude Pulmonary Edema Relevant to Hawai‘i?

    PubMed Central

    2014-01-01

    High altitude clinical syndromes have been described in the medical literature but may be under recognized in the state of Hawai‘i. As tourism increases, high altitude injuries may follow given the easy access to high altitude attractions. Visitors and clinicians should be aware of the dangers associated with the rapid ascent to high altitudes in the perceived comfort of a vehicle. This paper will review the basic pathophysiology, prevention, and treatment of the most serious of the high altitude clinical syndromes, high altitude pulmonary edema. PMID:25478294

  14. Infrared reflectance of high altitude clouds.

    PubMed

    Hovis, W A; Blaine, L R; Forman, M L

    1970-03-01

    The spectral reflectance characteristics of cirrostratus, cirrus clouds, and a jet contrail, in the 0.68-2.4-micro spectral interval, are of interest for remote sensing of cloud types from orbiting satellites. Measurements made with a down-looking spectrometer from a high altitude aircraft show differences between the signatures of naturally formed ice clouds, a fresh jet contrail, and a snow covered surface.

  15. A strategy for oxygen conditioning at high altitude: comparison with air conditioning.

    PubMed

    West, John B

    2015-09-15

    Large numbers of people live or work at high altitude, and many visit to trek or ski. The inevitable hypoxia impairs physical working capacity, and at higher altitudes there is also cognitive impairment. Twenty years ago oxygen enrichment of room air was introduced to reduce the hypoxia, and this is now used in dormitories, hotels, mines, and telescopes. However, recent advances in technology now allow large amounts of oxygen to be obtained from air or cryogenic oxygen sources. As a result it is now feasible to oxygenate large buildings and even institutions such as hospitals. An analogy can be drawn between air conditioning that has improved the living and working conditions of millions of people who live in hot climates and oxygen conditioning that can do the same at high altitude. Oxygen conditioning is similar to air conditioning except that instead of cooling the air, the oxygen concentration is raised, thus reducing the equivalent altitude. Oxygen conditioning on a large scale could transform living and working conditions at high altitude, where it could be valuable in homes, hospitals, schools, dormitories, company headquarters, banks, and legislative settings.

  16. A strategy for oxygen conditioning at high altitude: comparison with air conditioning.

    PubMed

    West, John B

    2015-09-15

    Large numbers of people live or work at high altitude, and many visit to trek or ski. The inevitable hypoxia impairs physical working capacity, and at higher altitudes there is also cognitive impairment. Twenty years ago oxygen enrichment of room air was introduced to reduce the hypoxia, and this is now used in dormitories, hotels, mines, and telescopes. However, recent advances in technology now allow large amounts of oxygen to be obtained from air or cryogenic oxygen sources. As a result it is now feasible to oxygenate large buildings and even institutions such as hospitals. An analogy can be drawn between air conditioning that has improved the living and working conditions of millions of people who live in hot climates and oxygen conditioning that can do the same at high altitude. Oxygen conditioning is similar to air conditioning except that instead of cooling the air, the oxygen concentration is raised, thus reducing the equivalent altitude. Oxygen conditioning on a large scale could transform living and working conditions at high altitude, where it could be valuable in homes, hospitals, schools, dormitories, company headquarters, banks, and legislative settings. PMID:26139219

  17. Barcroft's bold assertion: All dwellers at high altitudes are persons of impaired physical and mental powers.

    PubMed

    West, John B

    2016-03-01

    Barcroft's bold assertion that everyone at high altitude has physical and mental impairment compared with sea level was very provocative. It was a result of the expedition that he led to Cerro de Pasco in Peru, altitude 4300 m. Although it is clear that newcomers to high altitude have reduced physical powers, some people believe that this does not apply to permanent residents who have been at high altitude for generations. The best evidence supports Barcroft's contention, although permanent residents often perform better than acclimatized lowlanders. Turning to neuropsychological function, newcomers to high altitude certainly have some impairment, and there is evidence that the same applies to highlanders. However the notion that permanent residents are impaired is anathema to many people. For example the eminent Peruvian physician Carlos Monge took great exception to Barcroft's remark and even attributed it to the fact that Barcroft was suffering from acute mountain sickness when he made it! Monge referred to 'climatic aggression', by which he meant the negative consequences of the inevitable hypoxia of high altitude. Recent technological advances such as oxygen enrichment of room air can overcome this 'aggression'. This might be useful in some settings at high altitude such as a nursery where newborn babies are cared for, and possibly operating rooms where the surgeon's dexterity may be enhanced. Other situations might be dormitories, conference rooms, and perhaps some school rooms. These constitute possible ways by which the effects of Barcroft's assertion might be countered. PMID:25962370

  18. Barcroft's bold assertion: All dwellers at high altitudes are persons of impaired physical and mental powers.

    PubMed

    West, John B

    2016-03-01

    Barcroft's bold assertion that everyone at high altitude has physical and mental impairment compared with sea level was very provocative. It was a result of the expedition that he led to Cerro de Pasco in Peru, altitude 4300 m. Although it is clear that newcomers to high altitude have reduced physical powers, some people believe that this does not apply to permanent residents who have been at high altitude for generations. The best evidence supports Barcroft's contention, although permanent residents often perform better than acclimatized lowlanders. Turning to neuropsychological function, newcomers to high altitude certainly have some impairment, and there is evidence that the same applies to highlanders. However the notion that permanent residents are impaired is anathema to many people. For example the eminent Peruvian physician Carlos Monge took great exception to Barcroft's remark and even attributed it to the fact that Barcroft was suffering from acute mountain sickness when he made it! Monge referred to 'climatic aggression', by which he meant the negative consequences of the inevitable hypoxia of high altitude. Recent technological advances such as oxygen enrichment of room air can overcome this 'aggression'. This might be useful in some settings at high altitude such as a nursery where newborn babies are cared for, and possibly operating rooms where the surgeon's dexterity may be enhanced. Other situations might be dormitories, conference rooms, and perhaps some school rooms. These constitute possible ways by which the effects of Barcroft's assertion might be countered.

  19. The High Altitude Gamma Ray Observatory, HAWC

    NASA Astrophysics Data System (ADS)

    González, M. M.

    2011-10-01

    The Volcano Sierra Negra in Puebla, Mexico was selected to host HAWC (High Altitude Water Cherenkov), a unique obervatory of wide field of view (2π sr) capable of observing the sky continously at energies from 0.5 TeV to 100 TeV. HAWC is an array of 300 large water tanks (7.3 m diameter × 5 m depth) at an altitude of 4100 m. a. s. l. Each tank is instrumented with three upward-looking photomultipliers tubes. The full array will be capable of observing the most energetic gamma rays from the most violent events in the universe. HAWC will be 15 times more sensitive than its predecesor, Milagro. We present HAWC, the scientific case and capabilities.

  20. High altitude plumes at Mars morning terminator

    NASA Astrophysics Data System (ADS)

    Sanchez-Lavega, A.; Garcia Muñoz, A.; Garcia Melendo, E.; Perez-Hoyos, S.; Gomez Forrellad, J. M.; Pellier, C.; Delcroix, M.; Lopez Valverde, M. A.; González Galindo, F.; Jaeschke, W.; Parker, D.; Phillips, J.; Peach, D.

    2015-10-01

    In March and April 2012 two extremely high altitude plumes were observed at the Martian terminator reaching 200 -250 km or more above the surface[1]. They were located at about 195o West longitude and 45o South latitude (at Terra Cimmeria) and extended ˜500 -1,000 km in both North-South and East- West, and lasted for about 10 days. Both plumes exhibited day-to-day variability, and were seen at the morning terminator but not at the evening limb. Another large plume was captured on Hubble Space Telescope images in May 1997 at 99º West longitude and 3º South latitude, but its altitude cannot be pr ecisely determined.Broad-band photometry was performed of both events in the spectral range 255 nm -1052 nm. Based on the observed properties, we discuss different possible scenarios for the mechanism responsible for the formation of these plumes.

  1. Increased Cardiometabolic Risk and Worsening Hypoxemia at High Altitude.

    PubMed

    Miele, Catherine H; Schwartz, Alan R; Gilman, Robert H; Pham, Luu; Wise, Robert A; Davila-Roman, Victor G; Jun, Jonathan C; Polotsky, Vsevolod Y; Miranda, J Jaime; Leon-Velarde, Fabiola; Checkley, William

    2016-06-01

    < 0.01). In high-altitude populations in Puno, Peru, a higher BMI and lower pulmonary function were associated with lower resting daytime oxyhemoglobin saturation. Lower resting oxyhemoglobin saturation, in turn, was associated with higher odds of having multiple unfavorable cardiometabolic factors. Worsening hypoxia of any degree in high-altitude dwellers may be an independent risk factor for cardiovascular disease. PMID:27281472

  2. Trajectory Control For High Altitude Balloons

    NASA Astrophysics Data System (ADS)

    Aaron, K.; Nock, K.; Heun, M.; Wyszkowski, C.

    We will discuss the continuing development of the StratoSailTM Balloon Trajectory Control System presented at the 33rd COSPAR in 2000. A vertical wing suspended on a 15-km tether from a high altitude balloon uses the difference in wind velocity between the altitude of the balloon and the altitude of the wing to create an aerodynamic sideforce. This sideforce, transmitted to the balloon gondola via the tether, causes the balloon to move laterally. Although the balloon's resultant drift velocity is quite small (a few meters per second), the effect becomes significant over long periods of time (hours to days). Recently, a full-scale wing, rudder and boom assembly has been fabricated, a winch system testbed has been completed, and a lightweight tether with reduced susceptibility to ultraviolet damage has been developed. The development effort for this invention, with pending international patents, has been funded by the NASA/SBIR program in support of the Ultra Long Duration Balloon (ULDB) program.

  3. Impaired dynamic cerebral autoregulation at extreme high altitude even after acclimatization.

    PubMed

    Iwasaki, Ken-ichi; Zhang, Rong; Zuckerman, Julie H; Ogawa, Yojiro; Hansen, Lærke H; Levine, Benjamin David

    2011-01-01

    Cerebral blood flow (CBF) increases and dynamic cerebral autoregulation is impaired by acute hypoxia. We hypothesized that progressive hypocapnia with restoration of arterial oxygen content after altitude acclimatization would normalize CBF and dynamic cerebral autoregulation. To test this hypothesis, dynamic cerebral autoregulation was examined by spectral and transfer function analyses between arterial pressure and CBF velocity variabilities in 11 healthy members of the Danish High-Altitude Research Expedition during normoxia and acute hypoxia (10.5% O(2)) at sea level, and after acclimatization (for over 1 month at 5,260 m at Chacaltaya, Bolivia). Arterial pressure and CBF velocity in the middle cerebral artery (transcranial Doppler), were recorded on a beat-by-beat basis. Steady-state CBF velocity increased during acute hypoxia, but normalized after acclimatization with partial restoration of SaO(2) (acute, 78% ± 2%; chronic, 89% ± 1%) and progression of hypocapnia (end-tidal carbon dioxide: acute, 34 ± 2 mm Hg; chronic, 21 ± 1 mm Hg). Coherence (0.40 ± 0.05 Units at normoxia) and transfer function gain (0.77 ± 0.13 cm/s per mm Hg at normoxia) increased, and phase (0.86 ± 0.15 radians at normoxia) decreased significantly in the very-low-frequency range during acute hypoxia (gain, 141% ± 24%; coherence, 136% ± 29%; phase, -25% ± 22%), which persisted after acclimatization (gain, 136% ± 36%; coherence, 131% ± 50%; phase, -42% ± 13%), together indicating impaired dynamic cerebral autoregulation in this frequency range. The similarity between both acute and chronic conditions suggests that dynamic cerebral autoregulation is impaired by hypoxia even after successful acclimatization to an extreme high altitude.

  4. Aerodynamics of Shuttle Orbiter at high altitudes

    NASA Technical Reports Server (NTRS)

    Rault, Didier F. G.

    1993-01-01

    The high-altitude/high-Knudsen number aerodynamics of the Shuttle Orbiter are computed from Low-Earth Orbit down to 100 km using three-dimensional direct simulation Monte Carlo and free molecule codes. Results are compared with Blanchard's latest Shuttle aerodynamic model, which is based on in-flight accelerometer measurements, and bridging formula models. Good comparison is observed, except for the normal force and pitching moment coefficients. The present results were obtained for a generic Shuttle geometry configuration corresponding to a zero deflection for all control surfaces.

  5. Physiology studies at high altitude; why and how.

    PubMed

    Mellor, Adrian; Woods, D

    2014-06-01

    The military has always had an important role in high altitude research. This is due to the fact that mountainous regions often span borders and provide a safe haven to enemies. Deploying troops rapidly into high altitude environments presents major problems in terms of the development of high altitude illness. This paper examines the rationale for carrying out research at high altitude and the opportunities within the UK Defence Medical Services for carrying out this research.

  6. Tracking performance with two breathing oxygen concentrations after high altitude rapid decompression

    NASA Technical Reports Server (NTRS)

    Nesthus, Thomas E.; Schiflett, Samuel G.; Oakley, Carolyn J.

    1992-01-01

    Current military aircraft Liquid Oxygen (LOX) systems supply 99.5 pct. gaseous Aviator's Breathing Oxygen (ABO) to aircrew. Newer Molecular Sieve Oxygen Generation Systems (MSOGS) supply breathing gas concentration of 93 to 95 pct. O2. The margin is compared of hypoxia protection afforded by ABO and MSOGS breathing gas after a 5 psi differential rapid decompression (RD) in a hypobaric research chamber. The barometric pressures equivalent to the altitudes of 46000, 52000, 56000, and 60000 ft were achieved from respective base altitudes in 1 to 1.5 s decompressions. During each exposure, subjects remained at the simulated peak altitude breathing either 100 or 94 pct. O2 with positive pressure for 60 s, followed by a rapid descent to 40000 ft. Subjects used the Tactical Life Support System (TLSS) for high altitude protection. Subcritical tracking task performance on the Performance Evaluation Device (PED) provided psychomotor test measures. Overall tracking task performance results showed no differences between the MSOGS breathing O2 concentration of 94 pct. and ABO. Significance RMS error differences were found between the ground level and base altitude trials compared to peak altitude trials. The high positive breathing pressures occurring at the peak altitudes explained the differences.

  7. Pulmonary Embolism in Young Natives of High Altitude.

    PubMed

    Singhal, Sanjay; Bhattachar, Srinivasa Alasinga; Paliwal, Vivek; Malhotra, Vineet Kumar; Addya, Kalyani; Kotwal, Atul

    2016-01-01

    Thrombotic events are relatively common in high altitude areas and known to occur in young soldiers working at high altitude without usual risk factors associated with thrombosis at sea-level. However, till now, cases with thrombotic events were reported only in lowlanders staying at high altitude. These two cases of pulmonary embolism demonstrate that thrombotic events can occur in highlanders after a prolonged stay at the extreme altitude. PMID:27512534

  8. Pulmonary Embolism in Young Natives of High Altitude

    PubMed Central

    Singhal, Sanjay; Bhattachar, Srinivasa Alasinga; Paliwal, Vivek; Malhotra, Vineet Kumar; Addya, Kalyani; Kotwal, Atul

    2016-01-01

    Thrombotic events are relatively common in high altitude areas and known to occur in young soldiers working at high altitude without usual risk factors associated with thrombosis at sea-level. However, till now, cases with thrombotic events were reported only in lowlanders staying at high altitude. These two cases of pulmonary embolism demonstrate that thrombotic events can occur in highlanders after a prolonged stay at the extreme altitude. PMID:27512534

  9. High altitude balloon experiments at IIA

    NASA Astrophysics Data System (ADS)

    Nayak, Akshata; Sreejith, A. G.; Safonova, Margarita; Murthy, Jayant

    Recent advances in balloon experiments as well as in electronics have made it possible to fly scientific payloads at costs accessible to university departments. We have begun a program of high altitude ballooning at the Indian Institute of Astrophysics, Bengaluru. The primary purpose of this activity is to test low-cost ultraviolet (UV) payloads for eventual space flight, but we will also try scientific exploration of the phenomena occurring in the upper atmosphere, including sprites and meteorite impacts. We present the results of the initial experiments carried out at the CREST campus of IIA, Hosakote, and describe our plans for the future.

  10. Prevalence of Hypertension in a Tribal Land Locked Population at High Altitude

    PubMed Central

    Raina, Sunil Kumar; Chander, Vishav; Prasher, Chaman Lal; Raina, Sujeet

    2016-01-01

    Introduction. Extensive pubmed search reveals paucity of data on prevalence of hypertension in tribal population at high altitude. The data is all the more scarce from our part of India. Studies among tribal populations at high altitudes provide an interesting epidemiological window to study human evolution and adaptation to hypobaric hypoxia. Material and Methods. 401 participants above the age of 20 years were evaluated for blood pressure using a stratified simple random technique among villages located at high altitude. Results. Out of a total of 401 individuals studied 43 (males: 35; females: 8) were identified as hypertensive yielding a crude prevalence of 10.7%. The prevalence was higher in males (35/270; 12.9%) as compared to females (8/131; 6%). Prevalence was the highest in the age group of 30–39 among males (16/35; 45.7%) while it was the highest in the age group of 40–49 among females (7/8; 87%). Conclusions. Prevalence of 10.5% is noteworthy when interpreted in light of prevalence of hypertension in general population especially if hypobaric hypoxia is considered to have a protective effect on blood pressure in high altitude native populations. PMID:26989560

  11. The Andean Adaptive Toolkit to Counteract High Altitude Maladaptation: Genome-Wide and Phenotypic Analysis of the Collas

    PubMed Central

    Eichstaedt, Christina A.; Antão, Tiago; Pagani, Luca; Cardona, Alexia; Kivisild, Toomas; Mormina, Maru

    2014-01-01

    During their migrations out of Africa, humans successfully colonised and adapted to a wide range of habitats, including extreme high altitude environments, where reduced atmospheric oxygen (hypoxia) imposes a number of physiological challenges. This study evaluates genetic and phenotypic variation in the Colla population living in the Argentinean Andes above 3500 m and compares it to the nearby lowland Wichí group in an attempt to pinpoint evolutionary mechanisms underlying adaptation to high altitude hypoxia. We genotyped 730,525 SNPs in 25 individuals from each population. In genome-wide scans of extended haplotype homozygosity Collas showed the strongest signal around VEGFB, which plays an essential role in the ischemic heart, and ELTD1, another gene crucial for heart development and prevention of cardiac hypertrophy. Moreover, pathway enrichment analysis showed an overrepresentation of pathways associated with cardiac morphology. Taken together, these findings suggest that Colla highlanders may have evolved a toolkit of adaptative mechanisms resulting in cardiac reinforcement, most likely to counteract the adverse effects of the permanently increased haematocrit and associated shear forces that characterise the Andean response to hypoxia. Regulation of cerebral vascular flow also appears to be part of the adaptive response in Collas. These findings are not only relevant to understand the evolution of hypoxia protection in high altitude populations but may also suggest new avenues for medical research into conditions where hypoxia constitutes a detrimental factor. PMID:24686296

  12. The Andean adaptive toolkit to counteract high altitude maladaptation: genome-wide and phenotypic analysis of the Collas.

    PubMed

    Eichstaedt, Christina A; Antão, Tiago; Pagani, Luca; Cardona, Alexia; Kivisild, Toomas; Mormina, Maru

    2014-01-01

    During their migrations out of Africa, humans successfully colonised and adapted to a wide range of habitats, including extreme high altitude environments, where reduced atmospheric oxygen (hypoxia) imposes a number of physiological challenges. This study evaluates genetic and phenotypic variation in the Colla population living in the Argentinean Andes above 3500 m and compares it to the nearby lowland Wichí group in an attempt to pinpoint evolutionary mechanisms underlying adaptation to high altitude hypoxia. We genotyped 730,525 SNPs in 25 individuals from each population. In genome-wide scans of extended haplotype homozygosity Collas showed the strongest signal around VEGFB, which plays an essential role in the ischemic heart, and ELTD1, another gene crucial for heart development and prevention of cardiac hypertrophy. Moreover, pathway enrichment analysis showed an overrepresentation of pathways associated with cardiac morphology. Taken together, these findings suggest that Colla highlanders may have evolved a toolkit of adaptative mechanisms resulting in cardiac reinforcement, most likely to counteract the adverse effects of the permanently increased haematocrit and associated shear forces that characterise the Andean response to hypoxia. Regulation of cerebral vascular flow also appears to be part of the adaptive response in Collas. These findings are not only relevant to understand the evolution of hypoxia protection in high altitude populations but may also suggest new avenues for medical research into conditions where hypoxia constitutes a detrimental factor. PMID:24686296

  13. Domain Specific Changes in Cognition at High Altitude and Its Correlation with Hyperhomocysteinemia

    PubMed Central

    Sharma, Vijay K.; Das, Saroj K.; Dhar, Priyanka; Hota, Kalpana B.; Mahapatra, Bidhu B.; Vashishtha, Vivek; Kumar, Ashish; Hota, Sunil K.; Norboo, Tsering; Srivastava, Ravi B.

    2014-01-01

    Though acute exposure to hypobaric hypoxia is reported to impair cognitive performance, the effects of prolonged exposure on different cognitive domains have been less studied. The present study aimed at investigating the time dependent changes in cognitive performance on prolonged stay at high altitude and its correlation with electroencephalogram (EEG) and plasma homocysteine. The study was conducted on 761 male volunteers of 25–35 years age who had never been to high altitude and baseline data pertaining to domain specific cognitive performance, EEG and homocysteine was acquired at altitude ≤240 m mean sea level (MSL). The volunteers were inducted to an altitude of 4200–4600 m MSL and longitudinal follow-ups were conducted at durations of 03, 12 and 18 months. Neuropsychological assessment was performed for mild cognitive impairment (MCI), attention, information processing rate, visuo-spatial cognition and executive functioning. Total homocysteine (tHcy), vitamin B12 and folic acid were estimated. Mini Mental State Examination (MMSE) showed temporal increase in the percentage prevalence of MCI from 8.17% on 03 months of stay at high altitude to 18.54% on 18 months of stay. Impairment in visuo-spatial executive, attention, delayed recall and procedural memory related cognitive domains were detected following prolonged stay in high altitude. Increase in alpha wave amplitude in the T3, T4 and C3 regions was observed during the follow-ups which was inversely correlated (r = −0.68) to MMSE scores. The tHcy increased proportionately with duration of stay at high altitude and was correlated with MCI. No change in vitamin B12 and folic acid was observed. Our findings suggest that cognitive impairment is progressively associated with duration of stay at high altitude and is correlated with elevated tHcy in the plasma. Moreover, progressive MCI at high altitude occurs despite acclimatization and is independent of vitamin B12 and folic acid. PMID:24988417

  14. Pulmonary gas exchange, diffusing capacity in natives and newcomers at high altitude.

    PubMed

    Vincent, J; Hellot, M F; Vargas, E; Gautier, H; Pasquis, P; Lefrançois, R

    1978-08-01

    At high altitude, in resting conditions, no differences have been observed between High Altitude Natives (HAN) and acclimatized Sea Level Natives (SLN) in AaDO2, aADCO2 or venous admixture. In acclimatized SLN, AaDO2 is smaller than at sea level because of: (1) The minor effect on arterial oxygenation of the probably constant venous admixture. (2) The reduction of VA/Q inequality as shown by a smaller aADCO2. In HAN, DLCO is greater than in SLN; the contribution of DM or VC in this difference remains unsettled, mainly because of the difficulties of measurement of DM and VC in HAN suddenly exposed to acute hyperoxia. In SLN, in acute hypoxia, DLCO increased transitorily. Asynchronous mechanisms of adaptation to high altitude are evoked.

  15. Flight Dynamics of High Altitude Research Balloons

    NASA Astrophysics Data System (ADS)

    Sohl, Ian

    2010-10-01

    Dramatic motions have been observed by instrumentation loaded in payloads attached to high altitude weather balloons. Several HARBOR flights have been completed with six-axis attitude sensors and a high definition video camera that allowed us to analyze the balloon's motion. Turbulence in the atmosphere, especially near the jet stream, results in dramatic oscillations---sometimes swinging the payload above the balloon. Other unexpected motions include rapid spinning (as in a barrel roll) of the entire package. We are correlating these motions with observed atmospheric conditions and addressing issues related to payload safety, mission tracking, and recovery. Also of interest are the dynamics of balloon rupture at low atmospheric pressure and the response of the parachute recovery system to that environment. HARBOR (High Altitude Reconnaissance Balloon for Outreach and Research) is a program in which scientific payloads are designed, constructed, and flown by students using weather balloons to reach the edge of space. These flights are similar to the hundreds of weather balloons launched twice a day by the National Oceanic and Atmospheric Administration for which very little is actually known about the flight dynamics.

  16. Detection of ocean color changes from high altitudes

    NASA Technical Reports Server (NTRS)

    Hovis, W. A.; Forman, M. L.; Blaine, L. R.

    1973-01-01

    The detection of ocean color changes, thought to be due to chlorophyll concentrations and gelbstoffe variations, is attempted from high altitude (11.3km) and low altitude (0.3km). The atmospheric back scattering is shown to reduce contrast, but not sufficiently to obscure color change detection at high altitudes.

  17. Evaluating the Risks of High Altitude Travel in Chronic Liver Disease Patients.

    PubMed

    Luks, Andrew M; Swenson, Erik R

    2015-06-01

    Luks, Andrew M., and Erik R. Swenson. Clinician's Corner: Evaluating the risks of high altitude travel in chronic liver disease patients. High Alt Med Biol 16:80-88, 2015.--With improvements in the quality of health care, people with chronic medical conditions are experiencing better quality of life and increasingly participating in a wider array of activities, including travel to high altitude. Whenever people with chronic diseases travel to this environment, it is important to consider whether the physiologic responses to hypobaric hypoxia will interact with the underlying medical condition such that the risk of acute altitude illness is increased or the medical condition itself may worsen. This review considers these questions as they pertain to patients with chronic liver disease. While the limited available evidence suggests there is no evidence of liver injury or dysfunction in normal individuals traveling as high as 5000 m, there is reason to suspect that two groups of cirrhosis patients are at increased risk for problems, hepatopulmonary syndrome patients, who are at risk for severe hypoxemia following ascent, and portopulmonary hypertension patients who may be at risk for high altitude pulmonary edema and acute right ventricular dysfunction. While liver transplant patients may tolerate high altitude exposure without difficulty, no information is available regarding the risks of long-term residence at altitude with chronic liver disease. All travelers with cirrhosis require careful pre-travel evaluation to identify conditions that might predispose to problems at altitude and develop risk mitigation strategies for these issues. Patients also require detailed counseling about recognition, prevention, and treatment of acute altitude illness and may require different medication regimens to prevent or treat altitude illness than used in healthy individuals.

  18. Fit for high altitude: are hypoxic challenge tests useful?

    PubMed

    Matthys, Heinrich

    2011-01-01

    Altitude travel results in acute variations of barometric pressure, which induce different degrees of hypoxia, changing the gas contents in body tissues and cavities. Non ventilated air containing cavities may induce barotraumas of the lung (pneumothorax), sinuses and middle ear, with pain, vertigo and hearing loss. Commercial air planes keep their cabin pressure at an equivalent altitude of about 2,500 m. This leads to an increased respiratory drive which may also result in symptoms of emotional hyperventilation. In patients with preexisting respiratory pathology due to lung, cardiovascular, pleural, thoracic neuromuscular or obesity-related diseases (i.e. obstructive sleep apnea) an additional hypoxic stress may induce respiratory pump and/or heart failure. Clinical pre-altitude assessment must be disease-specific and it includes spirometry, pulsoximetry, ECG, pulmonary and systemic hypertension assessment. In patients with abnormal values we need, in addition, measurements of hemoglobin, pH, base excess, PaO2, and PaCO2 to evaluate whether O2- and CO2-transport is sufficient.Instead of the hypoxia altitude simulation test (HAST), which is not without danger for patients with respiratory insufficiency, we prefer primarily a hyperoxic challenge. The supplementation of normobaric O2 gives us information on the acute reversibility of the arterial hypoxemia and the reduction of ventilation and pulmonary hypertension, as well as about the efficiency of the additional O2-flow needed during altitude exposure. For difficult judgements the performance of the test in a hypobaric chamber with and without supplemental O2-breathing remains the gold standard. The increasing numbers of drugs to treat acute pulmonary hypertension due to altitude exposure (acetazolamide, dexamethasone, nifedipine, sildenafil) or to other etiologies (anticoagulants, prostanoids, phosphodiesterase-5-inhibitors, endothelin receptor antagonists) including mechanical aids to reduce periodical or

  19. Fit for high altitude: are hypoxic challenge tests useful?

    PubMed Central

    2011-01-01

    Altitude travel results in acute variations of barometric pressure, which induce different degrees of hypoxia, changing the gas contents in body tissues and cavities. Non ventilated air containing cavities may induce barotraumas of the lung (pneumothorax), sinuses and middle ear, with pain, vertigo and hearing loss. Commercial air planes keep their cabin pressure at an equivalent altitude of about 2,500 m. This leads to an increased respiratory drive which may also result in symptoms of emotional hyperventilation. In patients with preexisting respiratory pathology due to lung, cardiovascular, pleural, thoracic neuromuscular or obesity-related diseases (i.e. obstructive sleep apnea) an additional hypoxic stress may induce respiratory pump and/or heart failure. Clinical pre-altitude assessment must be disease-specific and it includes spirometry, pulsoximetry, ECG, pulmonary and systemic hypertension assessment. In patients with abnormal values we need, in addition, measurements of hemoglobin, pH, base excess, PaO2, and PaCO2 to evaluate whether O2- and CO2-transport is sufficient. Instead of the hypoxia altitude simulation test (HAST), which is not without danger for patients with respiratory insufficiency, we prefer primarily a hyperoxic challenge. The supplementation of normobaric O2 gives us information on the acute reversibility of the arterial hypoxemia and the reduction of ventilation and pulmonary hypertension, as well as about the efficiency of the additional O2-flow needed during altitude exposure. For difficult judgements the performance of the test in a hypobaric chamber with and without supplemental O2-breathing remains the gold standard. The increasing numbers of drugs to treat acute pulmonary hypertension due to altitude exposure (acetazolamide, dexamethasone, nifedipine, sildenafil) or to other etiologies (anticoagulants, prostanoids, phosphodiesterase-5-inhibitors, endothelin receptor antagonists) including mechanical aids to reduce periodical or

  20. Fit for high altitude: are hypoxic challenge tests useful?

    PubMed

    Matthys, Heinrich

    2011-01-01

    Altitude travel results in acute variations of barometric pressure, which induce different degrees of hypoxia, changing the gas contents in body tissues and cavities. Non ventilated air containing cavities may induce barotraumas of the lung (pneumothorax), sinuses and middle ear, with pain, vertigo and hearing loss. Commercial air planes keep their cabin pressure at an equivalent altitude of about 2,500 m. This leads to an increased respiratory drive which may also result in symptoms of emotional hyperventilation. In patients with preexisting respiratory pathology due to lung, cardiovascular, pleural, thoracic neuromuscular or obesity-related diseases (i.e. obstructive sleep apnea) an additional hypoxic stress may induce respiratory pump and/or heart failure. Clinical pre-altitude assessment must be disease-specific and it includes spirometry, pulsoximetry, ECG, pulmonary and systemic hypertension assessment. In patients with abnormal values we need, in addition, measurements of hemoglobin, pH, base excess, PaO2, and PaCO2 to evaluate whether O2- and CO2-transport is sufficient.Instead of the hypoxia altitude simulation test (HAST), which is not without danger for patients with respiratory insufficiency, we prefer primarily a hyperoxic challenge. The supplementation of normobaric O2 gives us information on the acute reversibility of the arterial hypoxemia and the reduction of ventilation and pulmonary hypertension, as well as about the efficiency of the additional O2-flow needed during altitude exposure. For difficult judgements the performance of the test in a hypobaric chamber with and without supplemental O2-breathing remains the gold standard. The increasing numbers of drugs to treat acute pulmonary hypertension due to altitude exposure (acetazolamide, dexamethasone, nifedipine, sildenafil) or to other etiologies (anticoagulants, prostanoids, phosphodiesterase-5-inhibitors, endothelin receptor antagonists) including mechanical aids to reduce periodical or

  1. High altitude pulmonary oedema (HAPE) in an Indian pilgrim.

    PubMed

    Panthi, Sagar; Basnyat, Buddha

    2013-11-01

    Increasing number of Hindu pilgrims visit the Himalayas where some of them suffer from high altitude illness including the life threatening forms, high altitude pulmonary oedema (HAPE) and high altitude cerebral oedema. Compared to tourists and trekkers, pilgrims are usually ignorant about altitude illness. This is a case of a pilgrim who suffered from HAPE on his trip to Kailash-Mansarovar and is brought to a tertiary level hospital in Kathmandu. This report emphasises on how to treat a patient with HAPE, a disease which is increasingly being seen in the high altitude pilgrim population. PMID:24974506

  2. Aerodynamics of heat exchangers for high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Drela, Mark

    1996-01-01

    Reduction of convective beat transfer with altitude dictates unusually large beat exchangers for piston- engined high-altitude aircraft The relatively large aircraft drag fraction associated with cooling at high altitudes makes the efficient design of the entire heat exchanger installation an essential part of the aircraft's aerodynamic design. The parameters that directly influence cooling drag are developed in the context of high-altitude flight Candidate wing airfoils that incorporate heat exchangers are examined. Such integrated wing-airfoil/heat-exchanger installations appear to be attractive alternatives to isolated heat.exchanger installations. Examples are drawn from integrated installations on existing or planned high-altitude aircraft.

  3. Changes in labial capillary density on ascent to and descent from high altitude

    PubMed Central

    Gilbert-Kawai, Edward; Coppel, Jonny; Phillip, Hennis; Grocott, Michael; Ince, Can; Martin, Daniel

    2016-01-01

    Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site.  Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021). There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017). Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area), despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains elevated on

  4. High altitude living: genetic and environmental adaptation.

    PubMed

    Ramirez, G; Bittle, P A; Rosen, R; Rabb, H; Pineda, D

    1999-01-01

    High altitude (HA) living produces physiological changes for adaptation to chronic hypobaric-hypoxemic conditions. Although much is known about these physiologic adaptations, no clear separation has been made regarding what is "native" or "genetic" adaptation and what is "acquired." In this review, we describe the genetic vs. acquired adaptation and only include studies performed in a population native to HA and not in an acclimatized population or trekkers. The changes encountered in animals and humans living at HA in terms of hematology, muscular, respiratory, cerebral, cardiovascular, hormonal, fluid and electrolytes and reproduction, strongly suggest that genetics play a very important role in HA adaptation. Unfortunately, the characteristic physiology of HA natives has not been systematically defined to established specific measurable parameters of adaptation in comparison to the acquired ambient adaptation of the non-native population. Once the parameters are established, we can compare non-native populations exposed to HA that must emulate the HA physiology for a definite adaptation to be present. With measurable parameters, especially in the management of fluids and electrolytes, we can define how long it will take for a sea level native to adapt to an HA altitude. Until these studies are performed, speculation will continue and no rational medical intervention can be offered to HA newcomers who may experience HA difficulties.

  5. Development of the High Altitude Student Platform

    NASA Astrophysics Data System (ADS)

    Guzik, T. G.; Besse, S.; Calongne, A.; Dominique, A.; Ellison, S. B.; Gould, R.; Granger, D.; Olano, D.; Smith, D.; Stewart, M.; Wefel, J. P.

    2008-11-01

    The High Altitude Student Platform (HASP) was originally conceived to provide student groups with access to the near-space environment for flight durations and experiment capabilities intermediate between what is possible with small sounding balloons and low Earth orbit rocket launches. HASP is designed to carry up to twelve student payloads to an altitude of about 36 km with flight durations of 15 20 h using a small zero-pressure polyethylene film balloon. This provides a flight capability that can be used to flight-test compact satellites, prototypes and other small payloads designed and built by students. HASP includes a standard mechanical, power and communication interface for the student payload to simplify integration and allows the payloads to be fully exercised. Over the last two years a partnership between the NASA Balloon Program Office (BPO), Columbia Scientific Balloon Facility (CSBF), Louisiana State University (LSU), the Louisiana Board of Regents (BoR), and the Louisiana Space Consortium (LaSPACE) has led to the development, construction and, finally, the first flight of HASP with a complement of eight student payloads on September 4, 2006. Here we discuss the primary as-built HASP systems and features, the student payload interface, HASP performance during the first flight and plans for continuing HASP flights. The HASP project maintains a website at http://laspace.lsu.edu/hasp/ where flight application, interface documentation and status information can be obtained.

  6. Responses of the autonomic nervous system in altitude adapted and high altitude pulmonary oedema subjects

    NASA Astrophysics Data System (ADS)

    Mathew, Lazar; Purkayastha, S. S.; Jayashankar, A.; Radhakrishnan, U.; Sen Gupta, J.; Nayar, H. S.

    1985-06-01

    Studies were carried out to ascertain the role of sympatho-parasympathetic responses in the process of adaptation to altitude. The assessment of status of autonomic balance was carried out in a group of 20 young male subjects by recording their resting heart rate, blood pressure, oral temperature, mean skin temperature, extremity temperatures, pupillary diameter, cold pressor response, oxygen consumption, cardioacceleration during orthostasis and urinary excretion of catecholamines; in a thermoneutral laboratory. The same parameters were repeated on day 3 and at weekly intervals for a period of 3 weeks, after exposing them to 3,500 m; and also after return to sea level. At altitude, similar studies were carried out in a group of 10 acclimatized lowlanders, 10 high altitude natives and 6 patients who had recently recovered from high altitude pulmonary oedema. In another phase, similar studies were done in two groups of subjects, one representing 15 subjects who had stayed at altitude (3,500 4,000 m) without any ill effects and the other comprising of 10 subjects who had either suffered from high altitude pulmonary oedema (HAPO) or acute mountain sickness (AMS). The results revealed sympathetic overactivity on acute induction to altitude which showed gradual recovery on prolonged stay, the high altitude natives had preponderance to parasympathetic system. Sympathetic preponderance may not be an essential etiological factor for the causation of maladaptation syndromes.

  7. Military applications of hypoxic training for high-altitude operations.

    PubMed

    Muza, Stephen R

    2007-09-01

    Rapid deployment of unacclimatized soldiers to high mountainous environments causes debilitating effects on operational capabilities (physical work performance), and force health (altitude sickness). Most of these altitude-induced debilitations can be prevented or ameliorated by a wide range of physiological responses collectively referred to as altitude acclimatization. Acclimatization to a target altitude can be induced by slow progressive ascents or continuous sojourns at intermediate altitudes. However, this "altitude residency" requirement reduces their utilization in rapid response military missions that exploit the air mobility capability of modern military forces to quickly deploy to an area of operations on short notice. A more recent approach to induce altitude acclimatization is the use of daily intermittent hypoxic exposures (IHE) in lieu of continuous residence at high altitudes. IHE treatments consist of three elements: 1) IHE simulated altitude (inspired oxygen partial pressure: PIO2), 2) IHE session duration, and 3) total number of IHE sessions over the treatment period. This paper reviews and summarizes the results of 25 published IHE studies. This review finds that an IHE altitude>or=4000 m, and daily exposure duration of at least 1.5 h repeated over a week or more are required to have a high probability of developing altitude acclimatization. The efficacy of shorter duration (<1.5 h) hypoxic exposures at >or=4000 m simulated altitudes, and longer exposures (>4 h) at moderate altitudes (2500-3500 m) is not well documented. The predominate IHE-induced altitude acclimatization response appears to be increased arterial oxygen content through ventilatory acclimatization. Thus, IHE is a promising approach to provide the benefits of altitude acclimatization to low-altitude-based soldiers before their deployment to high mountainous regions.

  8. Power Budget Analysis for High Altitude Airships

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Elliott, James R.; King, Glen C.

    2006-01-01

    The High Altitude Airship (HAA) has various potential applications and mission scenarios that require onboard energy harvesting and power distribution systems. The energy source considered for the HAA s power budget is solar photon energy that allows the use of either photovoltaic (PV) cells or advanced thermoelectric (ATE) converters. Both PV cells and an ATE system utilizing high performance thermoelectric materials were briefly compared to identify the advantages of ATE for HAA applications in this study. The ATE can generate a higher quantity of harvested energy than PV cells by utilizing the cascaded efficiency of a three-staged ATE in a tandem mode configuration. Assuming that each stage of ATE material has the figure of merit of 5, the cascaded efficiency of a three-staged ATE system approaches the overall conversion efficiency greater than 60%. Based on this estimated efficiency, the configuration of a HAA and the power utility modules are defined.

  9. Neurologic decompression sickness following cabin pressure fluctuations at high altitude.

    PubMed

    Auten, Jonathan D; Kuhne, Michael A; Walker, Harlan M; Porter, Henry O

    2010-04-01

    Decompression sickness (DCS) occurs in diving, altitude chamber exposures, and unpressurized or depressurized high-altitude flights. Because DCS takes many forms, in-flight cases may be misinterpreted as hypoxia, hyperventilation, or viral illness, with resulting failure to respond appropriately. In this case, a 28-yr-old male pilot of a single-seat, tactical aircraft experienced 12 rapid pressure fluctuations while flying at 43,000 ft above sea level. He had no symptoms and decided to complete the flight, which required an additional 2 h in the air. Approximately 1 h later he began to experience fatigue, lightheadedness, and confusion, which he interpreted as onset of a viral illness. However, symptoms progressed to visual, cognitive, motor, and sensory degradations and it was with some difficulty that he landed safely at his destination. Neurologic DCS was suspected on initial evaluation by flight line medical personnel because of the delayed onset and symptom progression. He was transferred to a local Emergency Department and noted to have altered mental status, asymmetric motor deficits, and non-dermatomal paresthesias of the upper and lower extremities. Approximately 3.5 h after the incident and 2.5 h after the onset of symptoms he began hyperbaric oxygen therapy. He received partial relief at 30 min of the Navy DiveTable 6 and full resolution at 90 min; there were no recurrent symptoms at a 1-yr follow-up. This case highlights the importance of early recognition of in-flight DCS symptoms and landing as soon as possible rather than as soon as practical in all likely scenarios. PMID:20377149

  10. Changing Patterns of Neuropsychological Functioning in Children Living at High Altitude above and below 4000 M: A Report from the Bolivian Children Living at Altitude (BoCLA) Study

    ERIC Educational Resources Information Center

    Virues-Ortega, Javier; Bucks, Romola; Kirkham, Fenella J.; Baldeweg, Torsten; Baya-Botti, Ana; Hogan, Alexandra M.

    2011-01-01

    The brain is highly sensitive to environmental hypoxia. Little is known, however, about the neuropsychological effects of high altitude residence in the developing brain. We recently described only minor changes in processing speed in native Bolivian children and adolescents living at approximately 3700 m. However, evidence for loss of cerebral…

  11. Sleep apneas and high altitude newcomers.

    PubMed

    Goldenberg, F; Richalet, J P; Onnen, I; Antezana, A M

    1992-10-01

    Sleep and respiration data from two French medical high altitude expeditions (Annapurna 4,800 m and Mt Sajama 6,542 m) are presented. Difficulties in maintaining sleep and a SWS decrease were found with periodic breathing (PB) during both non-REM and REM sleep. Extent of PB varied considerably among subjects and was not correlated to the number of arousals but to the intercurrent wakefulness duration. There was a positive correlation between the time spent in PB and the individual hypoxic ventilatory drive. The relation between PB, nocturnal desaturation, and mountain sickness intensity are discussed. Acclimatization decreased the latency toward PB and improved sleep. Hypnotic benzodiazepine intake (loprazolam 1 mg) did not worsen either SWS depression or apneas and allowed normal sleep reappearance after acclimatization.

  12. HAWC: The high altitude water Cherenkov observatory

    NASA Astrophysics Data System (ADS)

    Goodman, Jordan A.

    2013-02-01

    The High Altitude Water Cherenkov Observatory (HAWC) is currently being deployed at 4100m above sea level on the Vulcan Sierra Negra near Puebla, Mexico. The HAWC observatory will consist of 250-300 Water Cherenkov Detectors totaling approximately 22,000 m2 of instrumented area. The water Cherenkov technique allows HAWC to have a nearly 100% duty cycle and large field of view, making the HAWC observatory an ideal instrument for the study of transient phenomena. With its large effective area, excellent angular and energy resolutions, and efficient gamma-hadron separation, HAWC will survey the TeV gamma-ray sky, measure spectra of galactic sources from 1 TeV to beyond 100 TeV, and map galactic diffuse gamma ray emission. The science goals, instrument performance and status of the HAWC observatory will be presented.

  13. High Altitude Supersonic Decelerator Test Vehicle

    NASA Technical Reports Server (NTRS)

    Cook, Brant T.; Blando, Guillermo; Kennett, Andrew; Von Der Heydt, Max; Wolff, John Luke; Yerdon, Mark

    2013-01-01

    The Low Density Supersonic Decelerator (LDSD) project is tasked by NASA's Office of the Chief Technologist (OCT) to advance the state of the art in Mars entry and descent technology in order to allow for larger payloads to be delivered to Mars at higher altitudes with better accuracy. The project will develop a 33.5 m Do Supersonic Ringsail (SSRS) parachute, 6m attached torus, robotic class Supersonic Inflatable Aerodynamic Decelerator (SIAD-R), and an 8 m attached isotensoid, exploration class Supersonic Inflatable Aerodynamic Decelerator (SIAD-E). The SSRS and SIAD-R should be brought to TRL-6, while the SIAD-E should be brought to TRL-5. As part of the qualification and development program, LDSD must perform a Mach-scaled Supersonic Flight Dynamics Test (SFDT) in order to demonstrate successful free flight dynamic deployments at Mars equivalent altitude, of all three technologies. In order to perform these tests, LDSD must design and build a test vehicle to deliver all technologies to approximately 180,000 ft and Mach 4, deploy a SIAD, free fly to approximately Mach 2, deploy the SSRS, record high-speed and high-resolution imagery of both deployments, as well as record data from an instrumentation suite capable of characterizing the technology induced vehicle dynamics. The vehicle must also be recoverable after splashdown into the ocean under a nominal flight, while guaranteeing forensic data protection in an off nominal catastrophic failure of a test article that could result in a terminal velocity, tumbling water impact.

  14. Live high, train low at natural altitude.

    PubMed

    Stray-Gundersen, J; Levine, B D

    2008-08-01

    For decades altitude training has been used by endurance athletes and coaches to enhance sea-level performance. Whether altitude training does, in fact, enhance sea level performance and, if so, by what means has been the subject of a number of investigations. Data produced principally by Levine and Stray-Gundersen have shown that living for 4 weeks at 2500 m, while performing the more intense training sessions near sea level will provide an average improvement in sea level endurance performance (duration of competition: 7-20 min) of approximately 1.5%, ranging from no improvement to 6% improvement. This benefit lasts for at least 3 weeks on return to sea level. Two mechanisms have been shown to be associated with improvement in performance. One is an increase in red cell mass ( approximately 8%) that results in an improved maximal oxygen uptake ( approximately 5%). That must be combined with maintenance of training velocities and oxygen flux to realize the improvement in subsequent sea level performance. We find no evidence of changes in running economy or markers of anaerobic energy utilization. Our results have been obtained in runners ranging from collegiate to elite. Wehrlin et al. have recently confirmed these results in elite orienteers. While there are no specific studies addressing the use of living high, training low in football players, it is likely that an improvement in maximal oxygen uptake, all other factors equal, would enhance football performance. This benefit must be weighed against the time away (4 weeks) from home and competition necessary to gain these benefits.

  15. Effect of high altitude and exercise on microvascular parameters in acclimatized subjects.

    PubMed

    Bauer, Andreas; Demetz, Florian; Bruegger, Dirk; Schmoelz, Martin; Schroepfer, Sebastian; Martignoni, André; Baschnegger, Heiko; Hoelzl, Josef; Thiel, Manfred; Choukér, Alexander; Peter, Klaus; Gamble, John; Christ, Frank

    2006-02-01

    The role of microvascular fluid shifts in the adaptation to hypobaric hypoxia and its contribution to the pathophysiology of AMS (acute mountain sickness) is unresolved. In a systematic prospective study, we investigated the effects of hypobaric hypoxia and physical exercise alone, and in combination, on microvascular fluid exchange and related factors. We used computer-assisted VCP (venous congestion plethysmography) on the calves of ten altitude-acclimatized volunteers. We investigated the effects of: (i) actively climbing to an altitude of 3196 m, (ii) airlifting these subjects to the same altitude, and (iii) exercise at low altitude. CFC (capillary filtration capacity), Pvi (isovolumetric venous pressure) and Qa (calf blood flow) were assessed before and after each procedure and then repeated after an overnight rest. Measurements of CFC showed no evidence of increased microvascular permeability after any of the procedures. Pvi was significantly decreased (P<0.001) from 20.3+/-4.4 to 8.9+/-4.3 mmHg after active ascent, and was still significantly lower (P=0.009) after overnight rest at high altitude (13.6+/-5.9 mmHg). No such changes were observed after the passive ascent (16.7+/-4.0 mmHg at baseline; 17.3+/-4.5 mmHg after passive ascent; and 19.9+/-5.3 mmHg after overnight rest) or after exercise at low altitude. After the active ascent, Qa was significantly increased. We also found a significant correlation between Qa, Pvi and the number of circulating white blood cells. In conclusion, we found evidence to support the hypothesis that increased microvascular permeability associated with AMS does not occur in acclimatized subjects. We also observed that the microvascular equilibrium pressure (Pvi) fell in inverse relation to the increase in Qa, especially in hypoxic exercise. We hypothesize that this inverse relationship reflects the haemodynamic changes at the microvascular interface, possibly attributable to the flow-induced increases in endothelial surface

  16. Genome-wide analysis reveals adaptation to high altitudes in Tibetan sheep

    PubMed Central

    Wei, Caihong; Wang, Huihua; Liu, Gang; Zhao, Fuping; Kijas, James W.; Ma, Youji; Lu, Jian; Zhang, Li; Cao, Jiaxue; Wu, Mingming; Wang, Guangkai; Liu, Ruizao; Liu, Zhen; Zhang, Shuzhen; Liu, Chousheng; Du, Lixin

    2016-01-01

    Tibetan sheep have lived on the Tibetan Plateau for thousands of years; however, the process and consequences of adaptation to this extreme environment have not been elucidated for important livestock such as sheep. Here, seven sheep breeds, representing both highland and lowland breeds from different areas of China, were genotyped for a genome-wide collection of single-nucleotide polymorphisms (SNPs). The FST and XP-EHH approaches were used to identify regions harbouring local positive selection between these highland and lowland breeds, and 236 genes were identified. We detected selection events spanning genes involved in angiogenesis, energy production and erythropoiesis. In particular, several candidate genes were associated with high-altitude hypoxia, including EPAS1, CRYAA, LONP1, NF1, DPP4, SOD1, PPARG and SOCS2. EPAS1 plays a crucial role in hypoxia adaption; therefore, we investigated the exon sequences of EPAS1 and identified 12 mutations. Analysis of the relationship between blood-related phenotypes and EPAS1 genotypes in additional highland sheep revealed that a homozygous mutation at a relatively conserved site in the EPAS1 3′ untranslated region was associated with increased mean corpuscular haemoglobin concentration and mean corpuscular volume. Taken together, our results provide evidence of the genetic diversity of highland sheep and indicate potential high-altitude hypoxia adaptation mechanisms, including the role of EPAS1 in adaptation. PMID:27230812

  17. Fifty fertile years: anthropologists' studies of reproduction in high altitude natives.

    PubMed

    Vitzthum, Virginia J

    2013-01-01

    Early European colonists of the Andes had difficulties in reproducing, a fact that underpins the hypothesis that reproduction is impaired amongst all humans at high altitudes. Yet a 16th century missionary wrote, "… the Indians are healthiest and where they multiply the most prolifically is in these same cold air-tempers, … [yet most children of the Spaniards] when born in such regions do not survive." These observations suggest that humans at high altitudes are subjected to strong natural selection from hypoxia, cold and limited food sources and, furthermore, that human populations can and have adapted, and continue to adapt, to these conditions. Informed by multiple approaches and theoretical frameworks, anthropologists have investigated to what extent and precisely how high altitude environments impact human reproductive functioning and fertility. Analyses of the proximate determinants of natural fertility suggest that behaviors (breast/infant feeding practices in the Andes, and marriage practices and religious celibacy in the Himalaya) are major determinants of fertility in high altitude populations. Furthermore, data from Project REPA (Reproduction and Ecology in Provincía Aroma), a longitudinal study in rural Bolivia, demonstrate that fecundity is not impaired in this indigenous altiplano population, and that the risk for early pregnancy loss (EPL) is not elevated by environmental hypoxia but does vary seasonally with the agricultural cycle (contra to the assumption that EPLs are due almost entirely to genetically flawed concepti). This review discusses these and other findings that reveal the complex and dynamic adaptations of human reproductive functioning in high altitude environments.

  18. High-altitude adaptation of Tibetan chicken from MT-COI and ATP-6 perspective.

    PubMed

    Zhao, Xiaoling; Wu, Nan; Zhu, Qing; Gaur, Uma; Gu, Ting; Li, Diyan

    2016-09-01

    The problem of hypoxia adaptation in high altitudes is an unsolved brainteaser in the field of life sciences. As one of the best chicken breeds with adaptability to highland environment, the Tibetan chicken, is genetically different from lowland chicken breeds. In order to gain a better understanding of the mechanism of hypoxic adaptability in high altitude, in the present study, we focused on the MT-COI together with ATP-6 gene to explore the regulatory mechanisms for hypoxia adaptability in Tibet chicken. Here, we sequenced MT-COI of 29 Tibetan chickens and 30 Chinese domestic chickens and ATP-6 gene of 28 Tibetan chickens and 29 Chinese domestic chickens. In MT-COI gene, 9 single nucleotide polymorphisms (SNPs) were detected though none of these was a missense mutation, confirming the fact that MT-COI gene is a largely conservative sequence. In ATP-6 gene, 6 single nucleotide polymorphisms (SNPs) were detected and we found a missense mutation (m.9441G > A) in the ATP-6 gene of Tibetan chicken resulting in an amino acid substitution. Due to the critical role of ATP-6 gene in the proton translocation and energy metabolism, we speculated the possibility of this mutation playing an important role in easier energy conversion and metabolism in Tibetan chickens than Chinese domestic chickens so as to better adapt to the harsh environment of the high-altitude areas. The Median-joining profile also suggested that haplotype Ha2 has the ancestral position to the other haplotypes and has significant relationship with high-altitude adaptation in ATP-6 gene. Therefore, we considered that the polymorphism (m.9441G > A) in the ATP-6 gene may affect the specific functions of ATP-6 enzyme relating to high-altitude adaptation of Tibetan chicken and MT-COI gene is a largely conservative sequence.

  19. Chronic intermittent high altitude exposure, occupation, and body mass index in workers of mining industry.

    PubMed

    Esenamanova, Marina K; Kochkorova, Firuza A; Tsivinskaya, Tatyana A; Vinnikov, Denis; Aikimbaev, Kairgeldy

    2014-09-01

    The obesity and overweight rates in population exposed to chronic intermittent exposure to high altitudes are not well studied. The aim of the retrospective study was to evaluate whether there are differences in body mass index in different occupation groups working in intermittent shifts at mining industry at high altitude: 3800-4500 meters above sea level. Our study demonstrated that obesity and overweight are common in workers of high altitude mining industry exposed to chronic intermittent hypoxia. The obesity rate was lowest among miners as compared to blue- and white-collar employees (9.5% vs. 15.6% and 14.7%, p=0.013). Obesity and overweight were associated with older age, higher rates of increased blood pressure (8.79% and 5.72% vs. 1.92%), cholesterol (45.8% and 45.6% vs. 32.8%) and glucose (4.3% and 1.26% vs. 0.57%) levels as compared to normal body mass index category (p<0.0001 for all). There were differences in patterns of cholesterol and glucose levels in men and women employees according to occupation type. In conclusion, obesity and overweight rates are prevalent and associated with increase in blood pressure, cholesterol, and glucose levels in workers of mining industry exposed to intermittent high-altitude hypoxia. Therefore, assessment and monitoring of body mass index seems to be essential in those who live and work at high altitudes to supply the correct nutrition, modify risk factors, and prevent related disorders.

  20. Microgravity combustion experiment using high altitude balloon.

    NASA Astrophysics Data System (ADS)

    Kan, Yuji

    In JAXA, microgravity experiment system using a high altitude balloon was developed , for good microgravity environment and short turn-around time. In this publication, I give an account of themicrogravity experiment system and a combustion experiment to utilize the system. The balloon operated vehicle (BOV) as a microgravity experiment system was developed from 2004 to 2009. Features of the BOV are (1) BOV has double capsule structure. Outside-capsule and inside-capsule are kept the non-contact state by 3-axis drag-free control. (2) The payload is spherical shape and itsdiameter is about 300 mm. (3) Keep 10-4 G level microgravity environment for about 30 seconds However, BOV’s payload was small, and could not mount large experiment module. In this study, inherits the results of past, we established a new experimental system called “iBOV” in order toaccommodate larger payload. Features of the iBOV are (1) Drag-free control use for only vertical direction. (2) The payload is a cylindrical shape and its size is about 300 mm in diameter and 700 mm in height. (3) Keep 10-3-10-4 G level microgravity environment for about 30 seconds We have "Observation experiment of flame propagation behavior of the droplets column" as experiment using iBOV. This experiment is a theme that was selected first for technical demonstration of iBOV. We are conducting the flame propagation mechanism elucidation study of fuel droplets array was placed at regular intervals. We conducted a microgravity experiments using TEXUS rocket ESA and drop tower. For this microgravity combustion experiment using high altitude balloon, we use the Engineering Model (EM) for TEXUS rocket experiment. The EM (This payload) consists of combustion vessel, droplets supporter, droplets generator, fuel syringe, igniter, digital camera, high-speed camera. And, This payload was improved from the EM as follows. (1) Add a control unit. (2) Add inside batteries for control unit and heater of combustion

  1. [Hormonal variation during physical exertion at high altitude].

    PubMed

    Sutton, J; Garmendia, F

    1977-01-01

    The influence of the physical exercise at high altitude on the endocrine function was studied in 8 normal native men of sea level and in 8 natives men of high altitude. The sea level dwellers were studied both, at sea level, during an acute exposure to low barometric pressure and after 3 months of acclimatization to altitudes over 3,500 meters above the sea level. The experiments at high altitude were conducted at an altitude of 4,500 meters above the sea level. Two types of exercise were carried out, sub-maximal and maximal, at fasting state, between 8 and 10 a.m. During an acute exposure to altitude the physical exercise produced a marked rise of glucose, cortisol and growth hormone and a fall in the insulin content of plasma. In the sea level dwellers, acclimatized to altitude during 3 months, an elevation of growth hormone was observed only during maximal physical effort. Marked variation in glucose and cortisol were observed during both types of exercise. This shows that in these subjects some adaptative changes have ocurred but of lesser extent as those observed in altitude natives. In the high altitude native higher basal concentrations of growth hormone and glucagón as well as a lower glucose concentration in blood, were found. During exercise the high altitude dweller showed no significant changes in somatotropin, meanwhile an important elevation of cortisol occurred. These findings indicate that the high altitude native has metabolic and endocrine responses to exercise similar to those found in well fitted atletes of sea level. The exposure to altitude provoked a rise in glucagon concentration directly proportional to the time of exposition ot altitude. The physical exercise did not elucidate any change in the glucagon content of blood. PMID:753199

  2. High Altitude Observatory YBJ and ARGO Project

    NASA Astrophysics Data System (ADS)

    Tan, Y.; ARGO Collaboration

    A 5800 m2 RPC (Resistive Plate Chamber) full coverage air shower array is under construction in the YangBaJing Cosmic Ray Observatory, Tibet of China, by the ChinaItaly ARGO Collaboration. YBJ is a large flat grassland with an area 10 × 70 km2 at 4300m altitude, about 90 north west from Lhasa. Its nearby power station, asphalt road to Lhasa, passing railway (will be constructed during the coming 5 years), optical fiber link to the INTERNET, rare snow and other favourable weather conditions are well suitable for setting an Astrophysical Observatory here. The installation of a large area carpet-like detector in this peculiar site will allow one to perform an all-sky and high duty cycle study of high energy gamma rays from 100GeV to 50 TeV as well as accurate measurements on UHE cosmic rays. To insure the stable and uniform working condition of RPCs, a 104 M2 carpet hall was constructed, the RPC installation have be started in it since last November. The natural distribution and daily variation of temperature in the hall, the data concerning the performances of the installed RPCs, have been measured, the results are presented. ce

  3. Physiology in Medicine: A physiologic approach to prevention and treatment of acute high-altitude illnesses.

    PubMed

    Luks, Andrew M

    2015-03-01

    With the growing interest in adventure travel and the increasing ease and affordability of air, rail, and road-based transportation, increasing numbers of individuals are traveling to high altitude. The decline in barometric pressure and ambient oxygen tensions in this environment trigger a series of physiologic responses across organ systems and over a varying time frame that help the individual acclimatize to the low oxygen conditions but occasionally lead to maladaptive responses and one or several forms of acute altitude illness. The goal of this Physiology in Medicine article is to provide information that providers can use when counseling patients who present to primary care or travel medicine clinics seeking advice about how to prevent these problems. After discussing the primary physiologic responses to acute hypoxia from the organ to the molecular level in normal individuals, the review describes the main forms of acute altitude illness--acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema--and the basic approaches to their prevention and treatment of these problems, with an emphasis throughout on the physiologic basis for the development of these illnesses and their management.

  4. Physiology in Medicine: A physiologic approach to prevention and treatment of acute high-altitude illnesses.

    PubMed

    Luks, Andrew M

    2015-03-01

    With the growing interest in adventure travel and the increasing ease and affordability of air, rail, and road-based transportation, increasing numbers of individuals are traveling to high altitude. The decline in barometric pressure and ambient oxygen tensions in this environment trigger a series of physiologic responses across organ systems and over a varying time frame that help the individual acclimatize to the low oxygen conditions but occasionally lead to maladaptive responses and one or several forms of acute altitude illness. The goal of this Physiology in Medicine article is to provide information that providers can use when counseling patients who present to primary care or travel medicine clinics seeking advice about how to prevent these problems. After discussing the primary physiologic responses to acute hypoxia from the organ to the molecular level in normal individuals, the review describes the main forms of acute altitude illness--acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema--and the basic approaches to their prevention and treatment of these problems, with an emphasis throughout on the physiologic basis for the development of these illnesses and their management. PMID:25539941

  5. Plasma gonadotrophins, prolactin and corticosterone concentrations in male mice exposed to high altitude.

    PubMed

    Rattner, B A; Macmillan, B T; Michael, S D; Altland, P D

    1980-11-01

    Groups of sexually-naive male NFR/N mice were maintained at sea level or exposed to simulated altitudes of 18 000 ft (5486 m) or 22 000 ft (6705 m) for 1, 3, 7, 14 or 28 days. Plasma LH concentrations were slightly but not significantly depressed after 1 day of hypoxia. Plasma FSH values were reduced (P < 0.05) after 1, 7, 14 and 28 days of exposure to 22 000 ft when compared to the values in the other groups. Prolactin concentrations fluctuated considerably, but were not uniformly affected by high altitude exposure. Exposure to 18 000 ft resulted in an elevation of plasma corticosterone concentration (P < 0.05) for 3 days, which was followed by a decline to control group values, whereas at 22 000 ft corticosterone levels remained elevated. These findings indicate that plasma LH values are transiently reduced during the initial 24 h of exposure to high altitude and that plasma FSH concentrations are depressed in a sustained manner during severe hypoxia.

  6. NASA/USRA high altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Richardson, Michael; Gudino, Juan; Chen, Kenny; Luong, Tai; Wilkerson, Dave; Keyvani, Anoosh

    1990-01-01

    At the equator, the ozone layer ranges from approximately 80,000 to 130,000+ feet which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. This project is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 lbs. of payload. In addition, the aircraft must have a minimum of a 6,000 mile range. The low Mach number, payload, and long cruising time are all constraints imposed by the air sampling equipment. A pilot must be able to take control in the event of unforseen difficulties. Three aircraft configurations were determined to be the most suitable for meeting the above requirements, a joined-wing, a bi-plane, and a twin-boom conventional airplane. The techniques used have been deemed reasonable within the limits of 1990 technology. The performance of each configuration is analyzed to investigate the feasibility of the project requirements. In the event that a requirement can not be obtained within the given constraints, recommendations for proposal modifications are given.

  7. The High-Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    Mostafá, Miguel A.

    2014-10-01

    The High-Altitude Water Cherenkov (HAWC) observatory is a large field of view, continuously operated, TeV γ-ray experiment under construction at 4,100 m a.s.l. in Mexico. The HAWC observatory will have an order of magnitude better sensitivity, angular resolution, and background rejection than its predecessor, the Milagro experiment. The improved performance will allow us to detect both the transient and steady emissions, to study the Galactic diffuse emission at TeV energies, and to measure or constrain the TeV spectra of GeV γ-ray sources. In addition, HAWC will be the only ground-based instrument capable of detecting prompt emission from γ-ray bursts above 50 GeV. The HAWC observatory will consist of an array of 300 water Cherenkov detectors (WCDs), each with four photomultiplier tubes. This array is currently under construction on the flanks of the Sierra Negra volcano near the city of Puebla, Mexico. The first 30 WCDs (forming an array approximately the size of Milagro) were deployed in Summer 2012, and 100 WCDs will be taking data by May, 2013. We present in this paper the motivation for constructing the HAWC observatory, the status of the deployment, and the first results from the constantly growing array.

  8. The High Altitude Water Cherenkov (HAWC) Observatory

    NASA Astrophysics Data System (ADS)

    Springer, Wayne

    2014-06-01

    The High Altitude Water Cherenkov (HAWC) observatory is a continuously operated, wide field of view detector based upon a water Cherenkov technology developed by the Milagro experiment. HAWC observes, at an elevation of 4100 m on Sierra Negra Mountain in Mexico, extensive air showers initiated by gamma and cosmic rays. The completed detector will consist of 300 closely spaced water tanks each instrumented with four photomultiplier tubes that provide timing and charge information used to reconstruct energy and arrival direction. HAWC has been optimized to observe transient and steady emission from point as well as diffuse sources of gamma rays in the energy range from several hundred GeV to several hundred TeV. Studies in solar physics as well as the properties of cosmic rays will also be performed. HAWC has been making observations at various stages of deployment since completion of 10% of the array in summer 2012. A discussion of the detector design, science capabilities, current construction/commissioning status, and first results will be presented...

  9. High-altitude paragangliomas diagnostic and therapeutic considerations.

    PubMed

    Rodriguez-Cuevas, H; Lau, I; Rodriguez, H P

    1986-02-01

    Forty-one cervical paragangliomas that occurred in 40 patients born and living in Mexico City, Mexico, were studied. Tumors were most common in women (38/40); were unilateral (39/40), without a side preference; were of the nonhereditary type; and were not malignant. Tumor imaging with radionucleaide angiographic scanning was noninvasive, innocuous, and reliable for screening, whereas selective carotid angiography allowed for definitive diagnosis and clinical stratification of patients. Surgical resection was performed in 29 patients; in 23 cases, en bloc resection was accomplished without a vascular compromise, whereas in 4 patients, a portion of the external carotid artery had to be ligated and resected. Two other patients required a vascular graft to restore blood flow to the internal carotid. Seven patients had postoperative transient cranial nerve palsies, and one had an incomplete hemiplegia. Permanent nerve damage occurred in seven patients. It was concluded that high-altitude paragangliomas are hyperplastic growths that result from adaptation to hypoxia. They are rarely true neoplasm and, in general, are not associated with functional loss. In view of this and of the high morbidity rate associated with surgical removal, it was recommended that these patients be referred to research centers where efforts toward the elucidation of the etiology and pathophysiology of these tumors can be carried out. Surgery should be reserved for symptomatic cases or cases in which the diagnosis remains in doubt. The decision to operate must weigh the following factors: The tumor's benign nature, its slow growth rate, the technical difficulties associated with its resection, the high postoperative morbidity rate, and the general condition of the patient. PMID:3943005

  10. Effects of growth, diving history, and high altitude on blood oxygen capacity in harbor seals

    NASA Technical Reports Server (NTRS)

    Kodama, A. M.; Elsner, R.; Pace, N.

    1977-01-01

    Blood volume and body composition for diving and nondiving harbor seals were measured at six-week intervals during a 10-month period of captitivity. Whole body hematocrit, red cell volume per kg of lean body mass, and total circulating hemoglobin per kg lean body mass were significantly higher in the diving group, but relatively large blood volumes expressed in terms of body weight (11-12%) were found in both groups. A pair of harbor seals exposed to high altitude for about three months registered significant increases in red cell volume, blood hemoglobin levels, and blood volume expressed in terms of body weight; results of alveolar gas analyses indicate that hyperventilation also occurred. These typical mammalian responses to hypoxia suggest that the harbor seal's large blood volume and high hemoglobin content are an expression of phylogenetic control, and that in spite of its adaptability to apnea during its diving life, the animal cannot be considered preacclimatized to high altitude.

  11. Ventilation and hypoxic ventilatory response of Tibetan and Aymara high altitude natives.

    PubMed

    Beall, C M; Strohl, K P; Blangero, J; Williams-Blangero, S; Almasy, L A; Decker, M J; Worthman, C M; Goldstein, M C; Vargas, E; Villena, M; Soria, R; Alarcon, A M; Gonzales, C

    1997-12-01

    Newcomers acclimatizing to high altitude and adult male Tibetan high altitude natives have increased ventilation relative to sea level natives at sea level. However, Andean and Rocky Mountain high altitude natives have an intermediate level of ventilation lower than that of newcomers and Tibetan high altitude natives although generally higher than that of sea level natives at sea level. Because the reason for the relative hypoventilation of some high altitude native populations was unknown, a study was designed to describe ventilation from adolescence through old age in samples of Tibetan and Andean high altitude natives and to estimate the relative genetic and environmental influences. This paper compares resting ventilation and hypoxic ventilatory response (HVR) of 320 Tibetans 9-82 years of age and 542 Bolivian Aymara 13-94 years of age, native residents at 3,800-4,065 m. Tibetan resting ventilation was roughly 1.5 times higher and Tibetan HVR was roughly double that of Aymara. Greater duration of hypoxia (older age) was not an important source of variation in resting ventilation or HVR in either sample. That is, contrary to previous studies, neither sample acquired hypoventilation in the age ranges under study. Within populations, greater severity of hypoxia (lower percent of oxygen saturation of arterial hemoglobin) was associated with slightly higher resting ventilation among Tibetans and lower resting ventilation and HVR among Aymara women, although the associations accounted for just 2-7% of the variation. Between populations, the Tibetan sample was more hypoxic and had higher resting ventilation and HVR. Other systematic environmental contrasts did not appear to elevate Tibetan or depress Aymara ventilation. There was more intrapopulation genetic variation in these traits in the Tibetan than the Aymara sample. Thirty-five percent of the Tibetan, but none of the Aymara, resting ventilation variance was due to genetic differences among individuals. Thirty

  12. Users guide to high altitude imagery of Michigan

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A guide to the high altitude imagery of Michigan outlines the areas of the state covered by selected recent high altitude aircraft and Earth Resources Technology Satellite flights. The types of remote sensing used are described. Maps of the flight coverage areas are included along with price lists of available imagery.

  13. Introductory address: lessons to be learned from high altitude.

    PubMed Central

    Houston, C. S.

    1979-01-01

    A historical account of the important landmarks in man's experience with the high altitude environment is followed by comments on the important stages in the understanding of its physiological effects. The work of The Mount Logan High Altitude Physiology Study on acute mountain sickness is reviewed from its inception in 1967 until the present. PMID:386292

  14. Biventricular thrombosis in a structurally normal heart at high altitude.

    PubMed

    Malani, Susheel; Chadha, Davinder; Banerji, Anup

    2014-01-01

    We present a rare case of biventricular thrombus in a young patient with a structurally normal heart at high altitude, complicated with pulmonary embolism. Detailed evaluation revealed him to have protein S deficiency. Altered environmental conditions at high altitude associated with protein S deficiency resulted in thrombus formation at an unusual location; the same is discussed in this case report.

  15. Antioxidant and oxidative stress responses of sojourners at high altitude in different climatic temperatures

    NASA Astrophysics Data System (ADS)

    Sinha, Sanchari; Singh, Som Nath; Saha, Mantu; Kain, T. C.; Tyagi, A. K.; Ray, Uday Sankar

    2010-01-01

    High altitude (HA) is a multi-stressor environment comprising hypobaric hypoxia and cold. Climatic temperature varies with seasonal variation at HA. The present study was undertaken to investigate the effect of ambient temperature on antioxidant profile among sojourners at HA. The study was conducted on sojourners exposed to an altitude of 4,560 m in two different seasons and categorized into two groups (SOJ 1, n = 63, ambient temp. at HA: -6º to +10ºC; SOJ 2, n = 81, ambient temp. at HA: 3º-22ºC). Blood was collected at sea level (SL) and after 4 weeks of HA exposure. Antioxidant enzymes showed significant upregulation in SOJ 2 at HA. In SOJ 1, superoxide dismutase and glutathione peroxidase showed significant upregulation but catalase and glutathione reductase showed significant decrease at HA. Non-enzymatic antioxidants showed significant reduction in SOJ 1 whereas a sustained antioxidant profile was observed in SOJ 2 at HA. Oxidative stress markers showed higher levels in SOJ 1 than SOJ 2 at HA. Differences observed between SOJ 1 and SOJ 2 at HA may be the consequence of different environmental temperatures. Cold stress was higher in SOJ 1 as evidenced from the significantly lower oral temperature in SOJ 1 as compared to SOJ 2. Cold- and hypoxia-induced increase in energy expenditure was significantly high in SOJ 1 than SOJ 2. To conclude, chronic exposure to hypoxia in moderate climatic temperature has a potential preconditioning effect on antioxidant system, but exposure to both cold and hypoxia causes greater oxidative stress due to altered metabolic rate.

  16. Effects of Ascent to High Altitude on Human Antimycobacterial Immunity

    PubMed Central

    Aldridge, Robert W.; Siedner, Mark J.; Necochea, Alejandro; Leybell, Inna; Valencia, Teresa; Herrera, Beatriz; Wiles, Siouxsie; Friedland, Jon S.; Gilman, Robert H.; Evans, Carlton A.

    2013-01-01

    Background Tuberculosis infection, disease and mortality are all less common at high than low altitude and ascent to high altitude was historically recommended for treatment. The immunological and mycobacterial mechanisms underlying the association between altitude and tuberculosis are unclear. We studied the effects of altitude on mycobacteria and antimycobacterial immunity. Methods Antimycobacterial immunity was assayed in 15 healthy adults residing at low altitude before and after they ascended to 3400 meters; and in 47 long-term high-altitude residents. Antimycobacterial immunity was assessed as the extent to which participants’ whole blood supported or restricted growth of genetically modified luminescent Bacille Calmette-Guérin (BCG) mycobacteria during 96 hours incubation. We developed a simplified whole blood assay that could be used by a technician in a low-technology setting. We used this to compare mycobacterial growth in participants’ whole blood versus positive-control culture broth and versus negative-control plasma. Results Measurements of mycobacterial luminescence predicted the number of mycobacterial colonies cultured six weeks later. At low altitude, mycobacteria grew in blood at similar rates to positive-control culture broth whereas ascent to high altitude was associated with restriction (p≤0.002) of mycobacterial growth to be 4-times less than in culture broth. At low altitude, mycobacteria grew in blood 25-times more than negative-control plasma whereas ascent to high altitude was associated with restriction (p≤0.01) of mycobacterial growth to be only 6-times more than in plasma. There was no evidence of differences in antimycobacterial immunity at high altitude between people who had recently ascended to high altitude versus long-term high-altitude residents. Conclusions An assay of luminescent mycobacterial growth in whole blood was adapted and found to be feasible in low-resource settings. This demonstrated that ascent to or

  17. Comparison of Live High: Train Low Altitude and Intermittent Hypoxic Exposure

    PubMed Central

    Humberstone-Gough, Clare E.; Saunders, Philo U.; Bonetti, Darrell L.; Stephens, Shaun; Bullock, Nicola; Anson, Judith M.; Gore, Christopher J.

    2013-01-01

    Live High:Train Low (LHTL) altitude training is a popular ergogenic aid amongst athletes. An alternative hypoxia protocol, acute (60-90 min daily) Intermittent Hypoxic Exposure (IHE), has shown potential for improving athletic performance. The aim of this study was to compare directly the effects of LHTL and IHE on the running and blood characteristics of elite triathletes. Changes in total haemoglobin mass (Hbmass), maximal oxygen consumption (VO2max), velocity at VO2max (vVO2max), time to exhaustion (TTE), running economy, maximal blood lactate concentration ([La]) and 3 mM [La] running speed were compared following 17 days of LHTL (240 h of hypoxia), IHE (10.2 h of hypoxia) or Placebo treatment in 24 Australian National Team triathletes (7 female, 17 male). There was a clear 3.2 ± 4.8% (mean ± 90% confidence limits) increase in Hbmass following LHTL compared with Placebo, whereas the corresponding change of -1.4 ± 4.5% in IHE was unclear. Following LHTL, running economy was 2.8 ± 4.4% improved compared to IHE and 3mM [La] running speed was 4.4 ± 4.5% improved compared to Placebo. After IHE, there were no beneficial changes in running economy or 3mM [La] running speed compared to Placebo. There were no clear changes in VO2max, vVO2max and TTE following either method of hypoxia. The clear difference in Hbmass response between LHTL and IHE indicated that the dose of hypoxia in IHE was insufficient to induce accelerated erythropoiesis. Improved running economy and 3mM [La] running speed following LHTL suggested that this method of hypoxic exposure may enhance performance at submaximal running speeds. Overall, there was no evidence to support the use of IHE in elite triathletes. Key Points Despite a clear 3.2% increase in haemoglobin mass following 17 days of Live High: Train Low altitude training, no change in maximal aerobic capacity was observed. There were positive changes in running economy and the lactate-speed relationship at submaximal running speeds

  18. The physiology of extremes: Ancel Keys and the International High Altitude Expedition of 1935.

    PubMed

    Tracy, Sarah W

    2012-01-01

    This article examines the International High Altitude Expedition of 1935 and its significance in the life and science of Ancel Keys. Both the expedition and Keys's story afford excellent opportunities to explore the growing reach of interwar physiology into extreme climates-whether built or natural. As IHAE scientists assessed human performance and adaptation to hypoxia, low barometric pressure, and cold, they not only illuminated the physiological and psychological processes of high altitude acclimatization, but they also drew borderlines between the normal and the pathological, paved the way for the neocolonial exploitation of natural and human resources in Latin America, and pioneered field methods in physiology that were adapted and adopted by the Allied Forces during the Second World War. This case study in the physiology of place reveals the power and persistence of environmental determinism within biomedicine well into the twentieth century. PMID:23263349

  19. The physiology of extremes: Ancel Keys and the International High Altitude Expedition of 1935.

    PubMed

    Tracy, Sarah W

    2012-01-01

    This article examines the International High Altitude Expedition of 1935 and its significance in the life and science of Ancel Keys. Both the expedition and Keys's story afford excellent opportunities to explore the growing reach of interwar physiology into extreme climates-whether built or natural. As IHAE scientists assessed human performance and adaptation to hypoxia, low barometric pressure, and cold, they not only illuminated the physiological and psychological processes of high altitude acclimatization, but they also drew borderlines between the normal and the pathological, paved the way for the neocolonial exploitation of natural and human resources in Latin America, and pioneered field methods in physiology that were adapted and adopted by the Allied Forces during the Second World War. This case study in the physiology of place reveals the power and persistence of environmental determinism within biomedicine well into the twentieth century.

  20. The effect of high altitude on olfactory functions.

    PubMed

    Altundağ, Aytuğ; Salihoglu, Murat; Çayönü, Melih; Cingi, Cemal; Tekeli, Hakan; Hummel, Thomas

    2014-03-01

    It is known that high-altitude trips cause nasal congestion, impaired nasal mucociliary transport rate, and increased nasal resistance, due to decreased partial oxygen pressure and dry air. It is also known that olfactory perception is affected by barometric pressure and humidity. The aim of the present study was to investigate whether olfactory function changes in relation to high altitude in a natural setting. The present study included 41 volunteers with no history of chronic rhinosinusitis or nasal polyposis. The study group consisted of 31 men (76 %) and 10 women (24 %); the mean age of the study population was 38 ± 10 years. Olfactory testing was conducted using "Sniffin' Sticks" at a high altitude (2,200 ms) and at sea level. Odor test scores for threshold and identification were significantly better at sea level than at high altitude (p < 0.001). The major finding of this investigation was that olfactory functions are decreased at high altitudes.

  1. Turbulent mixing in high-altitude explosions

    SciTech Connect

    Kuhl, A.L.; Bell, J.B. ); Ferguson, R.E. ); White, W.W.; McCartor, T.H. )

    1992-09-01

    Numerical simulations of a high-altitude explosion were performed using a Godunov code with Adaptive Mesh Refinement (AMR). The code solves the two-dimensional (2-D), time-dependent conservation laws of inviscid gas dynamics while AMR is used to focus the computational effort in the mixing regions. The calculations revealed that a spherical density interface embedded in this flow was unstable and rolled up into a turbulent mixing layer. The shape of the interface was qualitatively similar to experimental photographs. Initially, the mixing layer width grew as a linear function of time, but eventually it reached an asymptotically-constant value. The flow field was azimuthally-averaged to evaluate the mean-flow profiles and the R.M.S. fluctuation profiles across the mixing layer. The mean kinetic energy rapidly approached zero as the blast wave decayed, but the fluctuating kinetic energy asymptotically approached a small constant value (a fraction of a percent of the maximum kinetic energy). This represents the rotational kinetic energy driven by the vorticity field, that continued to mix the fluid indefinitely. It was shown that the vorticity field corresponds to a function that fluctuates between plus and minus values -- with a volume-averaged mean of zero. The amplitude of the vorticity fluctuations decayed as t[sup [minus]1]. The corresponding enstrophy increased linearly with time because of a cascade process for the mean-squared vorticity. This result is in good agreement with the 2-D calculations of turbulent flow as reported by G.K. Batchelor. The problem should be recalculated in 3-D to study the decay of turbulent mixing for spherical interfaces.

  2. Turbulent mixing in high-altitude explosions

    SciTech Connect

    Kuhl, A.L.; Bell, J.B.; Ferguson, R.E.; White, W.W.; McCartor, T.H.

    1992-09-01

    Numerical simulations of a high-altitude explosion were performed using a Godunov code with Adaptive Mesh Refinement (AMR). The code solves the two-dimensional (2-D), time-dependent conservation laws of inviscid gas dynamics while AMR is used to focus the computational effort in the mixing regions. The calculations revealed that a spherical density interface embedded in this flow was unstable and rolled up into a turbulent mixing layer. The shape of the interface was qualitatively similar to experimental photographs. Initially, the mixing layer width grew as a linear function of time, but eventually it reached an asymptotically-constant value. The flow field was azimuthally-averaged to evaluate the mean-flow profiles and the R.M.S. fluctuation profiles across the mixing layer. The mean kinetic energy rapidly approached zero as the blast wave decayed, but the fluctuating kinetic energy asymptotically approached a small constant value (a fraction of a percent of the maximum kinetic energy). This represents the rotational kinetic energy driven by the vorticity field, that continued to mix the fluid indefinitely. It was shown that the vorticity field corresponds to a function that fluctuates between plus and minus values -- with a volume-averaged mean of zero. The amplitude of the vorticity fluctuations decayed as t{sup {minus}1}. The corresponding enstrophy increased linearly with time because of a cascade process for the mean-squared vorticity. This result is in good agreement with the 2-D calculations of turbulent flow as reported by G.K. Batchelor. The problem should be recalculated in 3-D to study the decay of turbulent mixing for spherical interfaces.

  3. Subsonic Airplane For High-Altitude Research

    NASA Technical Reports Server (NTRS)

    Chambers, Alan; Reed, R. Dale

    1993-01-01

    Report discusses engineering issues considered in design of conceptual subsonic airplane intended to cruise at altitudes of 100,000 ft or higher. Airplane would carry scientific instruments for research in chemistry and physics of atmosphere, particularly, for studies of ozone hole, greenhouse gases, and climatic effects.

  4. Perspectives on functional adaptation of the high altitude native.

    PubMed

    Frisancho, A R

    1983-01-01

    The major physiological processes that enable humans to attain a complete acclimatization to high altitude are briefly reviewed. The available data indicate that: (a) complete acclimatization to high altitude is associated with changes of environmentally modifiable functional traits such as lung volume but not associated with the expression of genetically controlled features such as chest size; (b) as judged by measurements of maximal aerobic power, the high altitude native has attained at high altitude an adaptation that is comparable to that attained by the low altitude native at sea level; the available information suggests that such adaptation is acquired through growth and development in an hypoxic environment; at present, however, we do not know the developmental modifications that occur within each component of the oxygen transport system, such as ventilation, pulmonary diffusion, and oxygen transport, that enable a sea level native to attain a complete functional adaptation to high altitude; and (c) at comparable altitudes among high altitude natives, there are some inter-regional differences in hemopoietic response, so that the samples derived from mining regions of the Andes are characterized by higher hemoglobin concentration than those derived from non-mining areas or the Himalayas. The source of these differences remains to be investigated. PMID:6364176

  5. Renin and aldosterone at high altitude in man.

    PubMed

    Keynes, R J; Smith, G W; Slater, J D; Brown, M M; Brown, S E; Payne, N N; Jowett, T P; Monge, C C

    1982-01-01

    Measurements have been made of hormonal changes relevant to salt and water balance during prolonged exposure to hypoxia to improve our understanding of the syndrome of acute mountain sickness. We have attempted to delineate the detailed inter-relationships between the renin-aldosterone and the vasopressin systems by a metabolically controlled study, involving an orthostatic stress (45 degrees head-up tilt) and an injection of a standard dose of ACTH to test adrenal responsiveness. Three Caucasian medical students underwent a 7-day equilibration at 150 m (Lima, Peru), followed by a 6-day sojourn at 4350 m (Cerro de Pasco, Peru) and a final 7 days at 150 m. Measurements were made of sodium and potassium balance, body weight and the 24-h renal excretion of vasopressin, cortisol and aldosterone 18-glucuronide. These variables showed little change, except for that of aldosterone 18-glucuronide, which fell sharply at altitude and rebounded even more sharply on return to sea level. At altitude, basal plasma levels of renin activity and aldosterone fell, and the response to orthostasis was attenuated, but the fall of plasma renin activity, as compared to plasma aldosterone, was delayed; on return to sea level this dissociation was exacerbated with the return of normal renin responsiveness lagging behind that of aldosterone. We suggest that unknown factors which dissociate the orthodox renin-aldosterone relationship, other than the activity of the angiotensin I-converting enzyme, are operative on exposure to hypoxia. PMID:7057120

  6. Renin and aldosterone at high altitude in man.

    PubMed

    Keynes, R J; Smith, G W; Slater, J D; Brown, M M; Brown, S E; Payne, N N; Jowett, T P; Monge, C C

    1982-01-01

    Measurements have been made of hormonal changes relevant to salt and water balance during prolonged exposure to hypoxia to improve our understanding of the syndrome of acute mountain sickness. We have attempted to delineate the detailed inter-relationships between the renin-aldosterone and the vasopressin systems by a metabolically controlled study, involving an orthostatic stress (45 degrees head-up tilt) and an injection of a standard dose of ACTH to test adrenal responsiveness. Three Caucasian medical students underwent a 7-day equilibration at 150 m (Lima, Peru), followed by a 6-day sojourn at 4350 m (Cerro de Pasco, Peru) and a final 7 days at 150 m. Measurements were made of sodium and potassium balance, body weight and the 24-h renal excretion of vasopressin, cortisol and aldosterone 18-glucuronide. These variables showed little change, except for that of aldosterone 18-glucuronide, which fell sharply at altitude and rebounded even more sharply on return to sea level. At altitude, basal plasma levels of renin activity and aldosterone fell, and the response to orthostasis was attenuated, but the fall of plasma renin activity, as compared to plasma aldosterone, was delayed; on return to sea level this dissociation was exacerbated with the return of normal renin responsiveness lagging behind that of aldosterone. We suggest that unknown factors which dissociate the orthodox renin-aldosterone relationship, other than the activity of the angiotensin I-converting enzyme, are operative on exposure to hypoxia.

  7. Regulatory changes contribute to the adaptive enhancement of thermogenic capacity in high-altitude deer mice.

    PubMed

    Cheviron, Zachary A; Bachman, Gwendolyn C; Connaty, Alex D; McClelland, Grant B; Storz, Jay F

    2012-05-29

    In response to hypoxic stress, many animals compensate for a reduced cellular O(2) supply by suppressing total metabolism, thereby reducing O(2) demand. For small endotherms that are native to high-altitude environments, this is not always a viable strategy, as the capacity for sustained aerobic thermogenesis is critical for survival during periods of prolonged cold stress. For example, survivorship studies of deer mice (Peromyscus maniculatus) have demonstrated that thermogenic capacity is under strong directional selection at high altitude. Here, we integrate measures of whole-organism thermogenic performance with measures of metabolic enzyme activities and genomic transcriptional profiles to examine the mechanistic underpinnings of adaptive variation in this complex trait in deer mice that are native to different elevations. We demonstrate that highland deer mice have an enhanced thermogenic capacity under hypoxia compared with lowland conspecifics and a closely related lowland species, Peromyscus leucopus. Our findings suggest that the enhanced thermogenic performance of highland deer mice is largely attributable to an increased capacity to oxidize lipids as a primary metabolic fuel source. This enhanced capacity for aerobic thermogenesis is associated with elevated activities of muscle metabolic enzymes that influence flux through fatty-acid oxidation and oxidative phosphorylation pathways in high-altitude deer mice and by concomitant changes in the expression of genes in these same pathways. Contrary to predictions derived from studies of humans at high altitude, our results suggest that selection to sustain prolonged thermogenesis under hypoxia promotes a shift in metabolic fuel use in favor of lipids over carbohydrates. PMID:22586089

  8. Fertility of a high-altitude sheep model is compromised by deficiencies in both preovulatory follicle development and plasma LH availability.

    PubMed

    Parraguez, V H; Diaz, F; Cofré, E; Urquieta, B; De Los Reyes, M; Astiz, S; Gonzalez-Bulnes, A

    2014-12-01

    At high altitude, hypoxia and/or oxidative stress may compromise fertility. This study tested the relative effect of short- or long-term exposure to high-altitude hypobaric hypoxia and oxidative stress in sheep on preovulatory follicle dynamics and gonadotrophin secretion. Thus, growth dynamics, stereidogenic function and competence to ovulate of preovulatory follicles, as well as FSH and LH availability throughout the entire oestrous cycle, were compared among sheep native from low and high altitude, and sheep newcomers to high altitude. The results indicates that short-term exposure in sheep newcomers to high altitude has a deleterious effect on both the ovarian function (affecting preovulatory follicular development) and the pituitary function (diminishing plasma LH availability). On the other hand, there were no detected differences in the preovulatory follicular development in sheep adapted to high altitude for generations and, conversely, LH secretion was increased, which suggests an adaptive mechanism. The treatment with antioxidant agents during a relative short period for the time of folliculogenesis (approximately 1 month and a half) changed substantially the development of preovulatory follicles in short-term exposed sheep to similar patterns than in sheep native and living to both high and low altitude. These results highlight the role of oxidative stress in the detriment of the reproductive function in individuals recently exposed to high-altitude hypoxic environment. PMID:25251782

  9. Fertility of a high-altitude sheep model is compromised by deficiencies in both preovulatory follicle development and plasma LH availability.

    PubMed

    Parraguez, V H; Diaz, F; Cofré, E; Urquieta, B; De Los Reyes, M; Astiz, S; Gonzalez-Bulnes, A

    2014-12-01

    At high altitude, hypoxia and/or oxidative stress may compromise fertility. This study tested the relative effect of short- or long-term exposure to high-altitude hypobaric hypoxia and oxidative stress in sheep on preovulatory follicle dynamics and gonadotrophin secretion. Thus, growth dynamics, stereidogenic function and competence to ovulate of preovulatory follicles, as well as FSH and LH availability throughout the entire oestrous cycle, were compared among sheep native from low and high altitude, and sheep newcomers to high altitude. The results indicates that short-term exposure in sheep newcomers to high altitude has a deleterious effect on both the ovarian function (affecting preovulatory follicular development) and the pituitary function (diminishing plasma LH availability). On the other hand, there were no detected differences in the preovulatory follicular development in sheep adapted to high altitude for generations and, conversely, LH secretion was increased, which suggests an adaptive mechanism. The treatment with antioxidant agents during a relative short period for the time of folliculogenesis (approximately 1 month and a half) changed substantially the development of preovulatory follicles in short-term exposed sheep to similar patterns than in sheep native and living to both high and low altitude. These results highlight the role of oxidative stress in the detriment of the reproductive function in individuals recently exposed to high-altitude hypoxic environment.

  10. [HIGH ALTITUDE EXPOSURE IN TRAVELERS WITH PREEXISTING MEDICAL CONDITIONS].

    PubMed

    Mintzer, Dalya Navat; Leshem, Eyal; Chazan, Bibiana; Schwartz, Eli

    2015-11-01

    The number of travelers visiting high altitude regions is increasing. High altitude areas have become more accessible in recent years, and reaching areas at altitudes over 3000 meters above sea level has become more common than before. In many circumstances older travelers, who are more likely to have pre-existing chronic diseases and for whom altitude and hypoxic condition might be a risk, reach high altitudes in a fast and tight schedule, therefore having a shorter time for adaptation and acclimatization. Pre-travel consultation, including the discussion of chronic illnesses and medication use, is therefore crucial for the reduction of the risk of acute mountain sickness and preventing the deterioration of their pre-existing medical conditions.

  11. Widespread signals of convergent adaptation to high altitude in Asia and america.

    PubMed

    Foll, Matthieu; Gaggiotti, Oscar E; Daub, Josephine T; Vatsiou, Alexandra; Excoffier, Laurent

    2014-10-01

    Living at high altitude is one of the most difficult challenges that humans had to cope with during their evolution. Whereas several genomic studies have revealed some of the genetic bases of adaptations in Tibetan, Andean, and Ethiopian populations, relatively little evidence of convergent evolution to altitude in different continents has accumulated. This lack of evidence can be due to truly different evolutionary responses, but it can also be due to the low power of former studies that have mainly focused on populations from a single geographical region or performed separate analyses on multiple pairs of populations to avoid problems linked to shared histories between some populations. We introduce here a hierarchical Bayesian method to detect local adaptation that can deal with complex demographic histories. Our method can identify selection occurring at different scales, as well as convergent adaptation in different regions. We apply our approach to the analysis of a large SNP data set from low- and high-altitude human populations from America and Asia. The simultaneous analysis of these two geographic areas allows us to identify several candidate genome regions for altitudinal selection, and we show that convergent evolution among continents has been quite common. In addition to identifying several genes and biological processes involved in high-altitude adaptation, we identify two specific biological pathways that could have evolved in both continents to counter toxic effects induced by hypoxia.

  12. Effect of high altitude on sensitivity to the taste of phenylthiocarbamide

    NASA Astrophysics Data System (ADS)

    Singh, S. B.; Chatterjee, A.; Panjwani, U.; Yadav, D. K.; Selvamurthy, W.; Sharma, K. N.

    Sensitivity to the taste of phenylthiocarbamide (PTC) was studied using the Harris-Kalmus method in healthy human volunteers at sea level and then subsequently at an altitude of 3500 m over a period of 3 weeks, after which they were brought back to sea level. Blood sugar, insulin and blood cortisol levels were estimated weekly. The results indicated that, out of 51 subjects studied, 26 (55%) were PTC tasters at sea level. Eight of those unable to taste PTC at sea level tested as tasters at high altitude, and 2 of them reverted to being non-tasters on return to sea level. In the blood, an increase in cortisol and blood insulin levels was seen without any significant change in sugar levels. All the changes recorded at high altitude tended to return to basal values after re-induction to sea level. The study suggests that high-altitude hypoxia in some way, possibly involving changes in hormonal profile among other factors, causes an alteration in sensitivity to the taste of PTC, resulting in some of the individuals shifting to lower PTC sensitivity.

  13. Aging, High Altitude, and Blood Pressure: A Complex Relationship.

    PubMed

    Parati, Gianfranco; Ochoa, Juan Eugenio; Torlasco, Camilla; Salvi, Paolo; Lombardi, Carolina; Bilo, Grzegorz

    2015-06-01

    Parati, Gianfranco, Juan Eugenio Ochoa, Camilla Torlasco, Paolo Salvi, Carolina Lombardi, and Grzegorz Bilo. Aging, high altitude, and blood pressure: A complex relationship. High Alt Biol Med 16:97-109, 2015.--Both aging and high altitude exposure may induce important changes in BP regulation, leading to significant increases in BP levels. By inducing atherosclerotic changes, stiffening of large arteries, renal dysfunction, and arterial baroreflex impairment, advancing age may induce progressive increases in systolic BP levels, promoting development and progression of arterial hypertension. It is also known, although mainly from studies in young or middle-aged subjects, that exposure to high altitude may influence different mechanisms involved in BP regulation (i.e., neural central and reflex control of sympathetic activity), leading to important increases in BP levels. The evidence is less clear, however, on whether and to what extent advancing age may influence the BP response to acute or chronic high altitude exposure. This is a question not only of scientific interest but also of practical relevance given the consistent number of elderly individuals who are exposed for short time periods (either for leisure or work) or live permanently at high altitude, in whom arterial hypertension is frequently observed. This article will review the evidence available on the relationship between aging and blood pressure levels at high altitude, the pathophysiological mechanisms behind this complex association, as well as some questions of practical interest regarding antihypertensive treatment in elderly subjects, and the effects of antihypertensive drugs on blood pressure response during high altitude exposure.

  14. Improving oxygenation at high altitude: acclimatization and O2 enrichment.

    PubMed

    West, John B

    2003-01-01

    When lowlanders go to high altitude, the resulting oxygen deprivation impairs mental and physical performance, quality of sleep, and general well-being. This paper compares the effects of ventilatory acclimatization and oxygen enrichment of room air on the improvement of oxygenation as judged by the increase in the alveolar P(O2) and the reduction in equivalent altitude. The results show that, on the average, complete ventilatory acclimatization at an altitude of 5000 m increases the alveolar P(O2) by nearly 8 torr, which corresponds to a reduction in equivalent altitude of about 1000 m, although there is considerable individual variability. By comparison, oxygen enrichment to 27% at 5000 m can easily reduce the equivalent altitude to 3200 m, which is generally well tolerated. Because full ventilatory acclimatization at altitudes up to about 3600 m reduces the equivalent altitude to about 3000 m, oxygen enrichment is not justified for well-acclimatized persons. At an altitude of 4200 m, where several telescopes are located on the summit of Mauna Kea, full acclimatization reduces the equivalent altitude to about 3400 m, but the pattern of commuting probably would not allow this. Therefore, at this altitude, oxygen enrichment would be beneficial but is not essential. At higher altitudes such as 5050 m, where other telescopes are located or planned, the gain in oxygenation from acclimatization is insufficient to produce an adequate mental or physical performance for most work, and oxygen enrichment is highly desirable. Full ventilatory acclimatization requires at least a week of continuous exposure, although much of the improvement is seen in the first 2 days. PMID:14561244

  15. Archaic inheritance: supporting high-altitude life in Tibet.

    PubMed

    Huerta-Sánchez, Emilia; Casey, Fergal P

    2015-11-15

    The Tibetan Plateau, often called the roof of the world, sits at an average altitude exceeding 4,500 m. Because of its extreme altitude, the Plateau is one of the harshest human-inhabited environments in the world. This, however, did not impede human colonization, and the Tibetan people have made the Tibetan Plateau their home for many generations. Many studies have quantified their markedly different physiological response to altitude and proposed that Tibetans were genetically adapted. Recently, advances in sequencing technologies led to the discovery of a set of candidate genes which harbor mutations that are likely beneficial at high altitudes in Tibetans. Since then, other studies have further characterized this impressive adaptation. Here, in this minireview, we discuss the progress made since the discovery of the genes involved in Tibetans' adaptation to high altitude with a particular emphasis on describing the series of studies that led us to conclude that archaic human DNA likely contributed to this impressive adaptation.

  16. Optimal birthweights in Peruvian populations at high and low altitudes.

    PubMed

    Beall, C M

    1981-11-01

    This study tests the hypothesis that optimum birthweight for survival is lower among hospital-born infants in Puno, Peru (altitude 3860 m) than that among their counterparts at low altitude in Tacna, Peru (altitude 600 m). The data are derived from hospital birth records for 1971 and 1972 and municipal death records for 1971 through 1973. Linking these records permits analysis of the patterns of mortality in relation to birthweight. Stabilizing selection upon birthweight is operating in both populations. The high altitude population has a lower mean birthweight and a lower optimal birthweight. The Puno population is closer to its optimal birthweight distribution and, as a result of mortality during infancy, is approaching its optimum birthweight distribution for survival more rapidly than the Tacna population. It appears that the high altitude Puno population may well be adapted to its environment in the sense that there is less selective mortality on birthweight phenotypes.

  17. Autonomic Cardiovascular Responses in Acclimatized Lowlanders on Prolonged Stay at High Altitude: A Longitudinal Follow Up Study

    PubMed Central

    Dhar, Priyanka; Sharma, Vijay K.; Hota, Kalpana B.; Das, Saroj K.; Hota, Sunil K.; Srivastava, Ravi B.; Singh, Shashi B.

    2014-01-01

    Acute exposure to hypobaric hypoxia at high altitude is reported to cause sympathetic dominance that may contribute to the pathophysiology of high altitude illnesses. The effect of prolonged stay at high altitude on autonomic functions, however, remains to be explored. Thus, the present study aimed at investigating the effect of high altitude on autonomic neural control of cardiovascular responses by monitoring heart rate variability (HRV) during chronic hypobaric hypoxia. Baseline electrocardiography (ECG) data was acquired from the volunteers at mean sea level (MSL) (<250 m) in Rajasthan. Following induction of the study population to high altitude (4500–4800 m) in Ladakh region, ECG data was acquired from the volunteers after 6 months (ALL 6) and 18 months of induction (ALL 18). Out of 159 volunteers who underwent complete investigation during acquisition of baseline data, we have only included the data of 104 volunteers who constantly stayed at high altitude for 18 months to complete the final follow up after 18 months. HRV parameters, physiological indices and biochemical changes in serum were investigated. Our results show sympathetic hyperactivation along with compromise in parasympathetic activity in ALL 6 and ALL 18 when compared to baseline data. Reduction of sympathetic activity and increased parasympathetic response was however observed in ALL 18 when compared to ALL 6. Our findings suggest that autonomic response is regulated by two distinct mechanisms in the ALL 6 and ALL 18. While the autonomic alterations in the ALL 6 group could be attributed to increased sympathetic activity resulting from increased plasma catecholamine concentration, the sympathetic activity in ALL 18 group is associated with increased concentration of serum coronary risk factors and elevated homocysteine. These findings have important clinical implications in assessment of susceptibility to cardio-vascular risks in acclimatized lowlanders staying for prolonged duration at high

  18. High-Altitude Magnetic Survey Over the United States

    NASA Astrophysics Data System (ADS)

    Hildenbrand, T. G.; Keller, G.; Pellerin, L.; Phillips, J.; Ravat, D.; Sabaka, T.

    2003-12-01

    The year 2004 offers an exciting and cost-effective opportunity to acquire a high-altitude magnetic data set over the U.S. A national mission is presently being planned to collect IFSAR imagery in addition to total and vector magnetic field data at an altitude of about 15 km. High-altitude magnetic data, needed as a reference field to properly level the U.S. low-altitude magnetic data set (0.3 km altitude), will also provide new insights on fundamental tectonic and thermal processes, thereby enabling a new view of the structural and lithologic framework of continental and offshore regions. A correctly merged, low-altitude magnetic database, using high-altitude magnetic data as a reference field, will be one of the most important legacies of a high-altitude magnetic mission, as it will greatly expand the utility of the invaluable U.S. magnetic data. However, the high-altitude data also have considerable independent scientific value. These unique data will bridge the spectral gap between the spectrums of the low-altitude aeromagnetic and satellite magnetic data. Based on our understanding of the magnetic properties of the lithosphere, the high-altitude data will clearly aid in the solution of a broad range of applied Earth science issues related to: the conundrum of long-wavelength magnetic anomalies; geologic and tectonic processes of crustal accretion and evolution; thermal and mechanical properties of the lithosphere; societal concerns including localization of favorable areas for mineral, energy, and thermal resources; and mitigation of earthquake and volcanic hazards. The wavelength band of a high-altitude survey will be particularly helpful in studying the lower crust--its composition, structure, and thermal regime--and large geologic/tectonic structures, such as basement terranes. In addition, these results will provide significant new constraints for geological interpretation of complementary regional topographic, seismic, electromagnetic, gravity, and heat

  19. DLR HABLEG- High Altitude Balloon Launched Experimental Glider

    NASA Astrophysics Data System (ADS)

    Wlach, S.; Schwarzbauch, M.; Laiacker, M.

    2015-09-01

    The group Flying Robots at the DLR Institute of Robotics and Mechatronics in Oberpfaffenhofen conducts research on solar powered high altitude aircrafts. Due to the high altitude and the almost infinite mission duration, these platforms are also denoted as High Altitude Pseudo-Satellites (HAPS). This paper highlights some aspects of the design, building, integration and testing of a flying experimental platform for high altitudes. This unmanned aircraft, with a wingspan of 3 m and a mass of less than 10 kg, is meant to be launched as a glider from a high altitude balloon in 20 km altitude and shall investigate technologies for future large HAPS platforms. The aerodynamic requirements for high altitude flight included the development of a launch method allowing for a safe transition to horizontal flight from free-fall with low control authority. Due to the harsh environmental conditions in the stratosphere, the integration of electronic components in the airframe is a major effort. For regulatory reasons a reliable and situation dependent flight termination system had to be implemented. In May 2015 a flight campaign was conducted. The mission was a full success demonstrating that stratospheric research flights are feasible with rather small aircrafts.

  20. High Resolution ECG for Evaluation of Heart Function During Exposure to Subacute Hypobaric Hypoxia

    NASA Technical Reports Server (NTRS)

    Zupet, Petra; Finderle, Zarko; Schlegel, Todd T.; Princi, Tanja; Starc, Vito

    2010-01-01

    High altitude climbing presents a wide spectrum of health risks, including exposure to hypobaric hypoxia. Risks are also typically exacerbated by the difficulty in appropriately monitoring for early signs of organ dysfunction in remote areas. We investigated whether high resolution advanced ECG analysis might be helpful as a non-invasive and easy-to-use tool (e.g., instead of Doppler echocardiography) for evaluating early signs of heart overload in hypobaric hypoxia. Nine non-acclimatized healthy trained alpine rescuers (age 43.7 plus or minus 7.3 years) climbed in four days to the altitude of 4,200 m on Mount Ararat. Five-minute high-resolution 12-lead electrocardiograms (ECGs) were recorded (Cardiosoft) in each subject at rest in the supine position on different days but at the same time of day at four different altitudes: 400 m (reference altitude), 1,700 m, 3,200 m and 4,200 m. Changes in conventional and advanced resting ECG parameters, including in beat-to-beat QT and RR variability, waveform complexity, signal-averaged, high-frequency and spatial/spatiotemporal ECG was estimated by calculation of the regression coefficients in independent linear regression models. A p-value of less than 0.05 was adopted as statistically significant. As expected, the RR interval and its variability both decreased with increasing altitude, with trends k = -96 ms/1000 m with p = 0.000 and k = -9 ms/1000 m with p = 0.001, respectively. Significant changes were found in P-wave amplitude, which nearly doubled from the lowest to the highest altitude (k = 41.6 microvolt/1000 m with p = 0.000), and nearly significant changes in P-wave duration (k = 2.9 ms/1000 m with p = 0.059). Changes were less significant or non-significant in other studied parameters including those of waveform complexity, signal-averaged, high-frequency and spatial/spatiotemporal ECG. High resolution ECG analysis, particularly of the P wave, shows promise as a tool for monitoring early changes in heart function

  1. Chronic stress of rainbow trout Oncorhynchus mykiss at high altitude: a field study.

    PubMed

    Hunt von Herbing, I; Pan, T-C F; Méndez-Sánchez, F; Garduño-Paz, M; Hernández-Gallegos, O; Ruiz-Gómez, M L; Rodríguez-Vargas, G

    2015-07-01

    The stress response of Oncorhynchus mykiss in high-altitude farms in central Mexico was investigated over two seasons: the cool (9·1-13·7° C) dry winter season, and the warmer (14·7-15·9° C), wetter summer season. Fish were subjected to an acute stress test followed by sampling of six physiological variables: blood cortisol, glucose, lactate, total antioxidant capacity, haemoglobin concentration and per cent packed cell volume (VPC %). Multivariate analyses revealed that lactate and total antioxidant capacity were significantly higher in the summer, when water temperatures were warmer and moderate hypoxia (4·9-5·3 mg l(-1) ) prevailed. In contrast, plasma cortisol was significantly higher in the winter (mean ± s.e.: 76·7 ± 4·0 ng ml(-1) ) when temperatures were cooler and dissolved oxygen levels higher (6·05-7·9 mg l(-1) ), than in the summer (22·7 ± 3·8 ng ml(-1) ). Haemoglobin concentrations (mg dl(-1) ) were not significantly different between seasons, but VPC % was significantly higher in the summer (50%) than in the winter (35%). These results suggest that in summer, effects of high altitude on farmed fish are exacerbated by stresses of high temperatures and hypoxia, resulting in higher blood lactate, increased total antioxidant capacity and elevated VPC % levels. PMID:26148653

  2. Altitude and endurance training.

    PubMed

    Rusko, Heikki K; Tikkanen, Heikki O; Peltonen, Juha E

    2004-10-01

    The benefits of living and training at altitude (HiHi) for an improved altitude performance of athletes are clear, but controlled studies for an improved sea-level performance are controversial. The reasons for not having a positive effect of HiHi include: (1) the acclimatization effect may have been insufficient for elite athletes to stimulate an increase in red cell mass/haemoglobin mass because of too low an altitude (< 2000-2200 m) and/or too short an altitude training period (<3-4 weeks); (2) the training effect at altitude may have been compromised due to insufficient training stimuli for enhancing the function of the neuromuscular and cardiovascular systems; and (3) enhanced stress with possible overtraining symptoms and an increased frequency of infections. Moreover, the effects of hypoxia in the brain may influence both training intensity and physiological responses during training at altitude. Thus, interrupting hypoxic exposure by training in normoxia may be a key factor in avoiding or minimizing the noxious effects that are known to occur in chronic hypoxia. When comparing HiHi and HiLo (living high and training low), it is obvious that both can induce a positive acclimatization effect and increase the oxygen transport capacity of blood, at least in 'responders', if certain prerequisites are met. The minimum dose to attain a haematological acclimatization effect is > 12 h a day for at least 3 weeks at an altitude or simulated altitude of 2100-2500 m. Exposure to hypoxia appears to have some positive transfer effects on subsequent training in normoxia during and after HiLo. The increased oxygen transport capacity of blood allows training at higher intensity during and after HiLo in subsequent normoxia, thereby increasing the potential to improve some neuromuscular and cardiovascular determinants of endurance performance. The effects of hypoxic training and intermittent short-term severe hypoxia at rest are not yet clear and they require further study.

  3. Altitude and endurance training.

    PubMed

    Rusko, Heikki K; Tikkanen, Heikki O; Peltonen, Juha E

    2004-10-01

    The benefits of living and training at altitude (HiHi) for an improved altitude performance of athletes are clear, but controlled studies for an improved sea-level performance are controversial. The reasons for not having a positive effect of HiHi include: (1) the acclimatization effect may have been insufficient for elite athletes to stimulate an increase in red cell mass/haemoglobin mass because of too low an altitude (< 2000-2200 m) and/or too short an altitude training period (<3-4 weeks); (2) the training effect at altitude may have been compromised due to insufficient training stimuli for enhancing the function of the neuromuscular and cardiovascular systems; and (3) enhanced stress with possible overtraining symptoms and an increased frequency of infections. Moreover, the effects of hypoxia in the brain may influence both training intensity and physiological responses during training at altitude. Thus, interrupting hypoxic exposure by training in normoxia may be a key factor in avoiding or minimizing the noxious effects that are known to occur in chronic hypoxia. When comparing HiHi and HiLo (living high and training low), it is obvious that both can induce a positive acclimatization effect and increase the oxygen transport capacity of blood, at least in 'responders', if certain prerequisites are met. The minimum dose to attain a haematological acclimatization effect is > 12 h a day for at least 3 weeks at an altitude or simulated altitude of 2100-2500 m. Exposure to hypoxia appears to have some positive transfer effects on subsequent training in normoxia during and after HiLo. The increased oxygen transport capacity of blood allows training at higher intensity during and after HiLo in subsequent normoxia, thereby increasing the potential to improve some neuromuscular and cardiovascular determinants of endurance performance. The effects of hypoxic training and intermittent short-term severe hypoxia at rest are not yet clear and they require further study

  4. Periodic breathing at high altitude and ventilatory responses to O2 and CO2.

    PubMed

    Masuyama, S; Kohchiyama, S; Shinozaki, T; Okita, S; Kunitomo, F; Tojima, H; Kimura, H; Kuriyama, T; Honda, Y

    1989-01-01

    To determine the relationship between periodic breathing (PB) during sleep at high altitude and ventilatory chemosensitivities, we studied nine Japanese climbers who participated in the expedition to the Kunlun Mountains (7,167 m) in China in 1986. At sea level, ventilatory response to hypoxia (HVR) by isocapnic progressive hypoxia test and to hypercapnia (HCVR) by Read's method were examined. At altitude 5,360 m, respiratory movements of the chest and abdominal wall, SaO2, ECG, and HR were monitored. Seven climbers manifested PB during sleep. There was a significant correlation between PB during sleep and HVR and HCVR (p less than 0.05). All the climbers showed severe desaturation during sleep. There was a significant negative correlation between degree of desaturation during sleep and HVR (p less than 0.05). A negative correlation was also detected between PB and the degree of desaturation during sleep. We concluded that ventilatory chemosensitivities play an important role in eliciting PB and that climbers with high HVR can maintain their arterial oxygenation during sleep, due to hyperventilation induced by PB, which is considered an advantageous adaptation for lowland sojourners.

  5. Different gene expressions between cattle and yak provide insights into high-altitude adaptation.

    PubMed

    Wang, K; Yang, Y; Wang, L; Ma, T; Shang, H; Ding, L; Han, J; Qiu, Q

    2016-02-01

    DNA sequence variation has been widely reported as the genetic basis for adaptation, in both humans and other animals, to the hypoxic environment experienced at high altitudes. However, little is known about the patterns of gene expression underlying such hypoxic adaptations. In this study, we examined the differences in the transcriptomes of four organs (heart, kidney, liver and lung) between yak and cattle, a pair of closely related species distributed at high and low altitudes respectively. Of the four organs examined, heart shows the greatest differentiation between the two species in terms of gene expression profiles. Detailed analyses demonstrated that some genes associated with the oxygen supply system and the defense systems that respond to threats of hypoxia are differentially expressed. In addition, genes with significantly differentiated patterns of expression in all organs exhibited an unexpected uniformity of regulation along with an elevated frequency of nonsynonymous substitutions. This co-evolution of protein sequences and gene expression patterns is likely to be correlated with the optimization of the yak metabolic system to resist hypoxia.

  6. A genome wide study of genetic adaptation to high altitude in feral Andean Horses of the páramo

    PubMed Central

    2013-01-01

    Background Life at high altitude results in physiological and metabolic challenges that put strong evolutionary pressure on performance due to oxidative stress, UV radiation and other factors dependent on the natural history of the species. To look for genes involved in altitude adaptation in a large herbivore, this study explored genome differentiation between a feral population of Andean horses introduced by the Spanish in the 1500s to the high Andes and their Iberian breed relatives. Results Using allelic genetic models and Fst analyses of ~50 K single nucleotide polymorphisms (SNPs) across the horse genome, 131 candidate genes for altitude adaptation were revealed (Bonferoni of p ≤ 2 × 10–7). Significant signals included the EPAS1 in the hypoxia-induction-pathway (HIF) that was previously discovered in human studies (p = 9.27 × 10-8); validating the approach and emphasizing the importance of this gene to hypoxia adaptation. Strong signals in the cytochrome P450 3A gene family (p = 1.5 ×10-8) indicate that other factors, such as highly endemic vegetation in altitude environments are also important in adaptation. Signals in tenuerin 2 (TENM2, p = 7.9 × 10-14) along with several other genes in the nervous system (gene categories representation p = 5.1 × 10-5) indicate the nervous system is important in altitude adaptation. Conclusions In this study of a large introduced herbivore, it becomes apparent that some gene pathways, such as the HIF pathway are universally important for high altitude adaptation in mammals, but several others may be selected upon based on the natural history of a species and the unique ecology of the altitude environment. PMID:24344830

  7. 33. GENERAL HIGH ALTITUDE AERIAL VIEW OF COMPLEX AND GENERAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. GENERAL HIGH ALTITUDE AERIAL VIEW OF COMPLEX AND GENERAL SETTING. October 1982 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 15, Upper Mississipi River (Arsenal Island), Rock Island, Rock Island County, IL

  8. 13. GENERAL HIGH ALTITUDE AERIAL VIEW OF COMPLEX AND GENERAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. GENERAL HIGH ALTITUDE AERIAL VIEW OF COMPLEX AND GENERAL SETTING. October 1982 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 17, Upper Mississippi River, New Boston, Mercer County, IL

  9. Association between MT-CO3 haplotypes and high-altitude adaptation in Tibetan chicken.

    PubMed

    Sun, Jing; Zhong, Hang; Chen, Shi-Yi; Yao, Yong-Gang; Liu, Yi-Ping

    2013-10-15

    Genetic mutation in cytochrome c oxidase subunit III gene (MT-CO3) could influence the kinetics of cytochrome c oxidase (COX), which catalyzes oxygen transport capacity in oxidative phosphorylation. However, the potential relationship between MT-CO3 variants and high-altitude adaptation remains poorly understood in Tibetan chicken. Here, we sequenced MT-CO3 gene of 125 Tibetan chickens and 144 Chinese domestic chickens in areas at a low elevation (below 1,000 m). Eight single nucleotide polymorphisms (SNPs) were detected; and five of them (m.10081A>G, m.10115G>A, m.10270G>A, m.10336A>G and m.10447C>T) shared by Tibetan chicken and lowland chicken with the significant difference in their respective allele frequencies. Nine haplotypes (H1-H9) were finally defined. Among them, haplotype H4 was positively associated with high-altitude adaptation whereas haplotypes H6, H7 and H8 had negative association with high-altitude adaptation. The Median-joining profile suggested that haplotype H5 had the ancestral position to the other haplotypes but had no significant relationship with high-altitude adaptation. However, there was only m.10081A>G mutation differed from haplotype H4 and H5. Results also suggested that chickens with A allele at m.10081A>G, had over 2.6 times than those with G allele in the probability of the ability to adapt hypoxia. It suggests that the synonymous mutation m.10081A>G may be a prerequisite for shaping high-altitude adaptation-specific haplotypes.

  10. High altitude pulmonary edema. Epidemiologic observations in Peru.

    PubMed

    Hultgren, H N; Marticorena, E A

    1978-10-01

    The incidence of high altitude pulmonary edema was examined by a survey (via questionnaire) of residents living at 3,750 meters (12,303 feet) in the mining community of La Oroya, Peru. Ninety-seven subjects made a total of 1,157 ascents to high altitude after a stay at sea level of longer than 14 days. Sixty-four subjects experienced at least one episode of high-altitude pulmonary edema. The incidence was higher in subjects aged 13 to 20 years, where 17 percent (15) of 90 ascents resulted in episodes of high-altitude pulmonary edema, than in subjects 21 years or older (3 percent; 18/686 ascents). Young subjects (2 to 12 years old) had more severe episodes of high-altitude pulmonary edema (81 percent; 30/37 episodes) than adults (22 percent; 4/18 episodes). No episodes were observed in children under two years old. Five subjects under 21 years of age experienced recurrent episodes. Our estimated incidence of severe episodes of high altitude pulmonary edema per ascent in adults (0.6 percent; 4/686) is similar to that reported by other workers (incidence of 0.15 to 0.57 percent) in various parts of the world. PMID:699645

  11. High altitude cerebral oedema during adventure training on Mount Kenya.

    PubMed

    Raitt, S

    2012-09-01

    The trekking ascent to Point Lenana (4,985m) on Mount Kenya is a popular objective for soldiers on adventurous training in Kenya. The standard route previously taken has been the Naro Moru route which involves an ascent rate far in excess of that recommended to avoid altitude illness. This article describes the case of a British soldier who developed high altitude cerebral oedema during an ascent of Point Lenana via the Naro Moro route. Recommendations to reduce the risk of altitude illness on Mount Kenya include alternative and more gradual routes of ascent. Early symptom recognition and descent are vital to prevent clinical deterioration.

  12. Letter to the Editor Reply to commentary by G. Sikri and S. Dua on the article "Correlation between single nucleotide polymorphisms in hypoxia-related genes and susceptibility to acute high-altitude pulmonary edema" published in Genetics and Molecular Research 14 (3): 11562-11572 to the letter published in Genet. Mol. Res. 14 (4): 15904-15905.

    PubMed

    Wu, L J

    2016-03-24

    The object in this study was a Han Chinese population in Lhasa, with 3658 m in altitude from Chengdu, which has 505 m in altitude by air. Within 24 to 48 h before the subjects arrived in the plateau, they completed a basic situation questionnaire, under the guidance of medical staff. Within 24 to 48 h after they reached the plateau, the subjects completed an acute plateau disease questionnaire. The diagnostic standard of HAPE and the diagnosis of acute plateau disease were adopted by the Lake Louise diagnostic standards in 1991 and the Chinese Medical Association promulgated the domestic diagnostic criteria on the Third National Plateau Medical Academic Seminar. Other diseases that cause acute symptoms of altitude sickness, such as plateau pulmonary edema, plateau cerebral edema, acute respiratory infections and neurosis, were excluded. According to the Lake Louise standard, questionnaire and symptom score values >3 points were diagnosed as HAPE. According to the national standard, the questionnaire and symptom score values >5 points were diagnosed as HAPE. At the present, morbidity of HAPE remains relatively high in China. The research shows that usually in the case of not taking preventive measures, according to the factors such as altitude, speed, and time of arrival, the incidence of HAPE is 30% to 90%. Epidemiological survey shows that HAPE happens at an altitude of 2500 m above the plateau. And an altitude of 3000 m above the plateau of China is occupied 1/6 of the total land area, the population of permanent residents is more than sixty million. We detected the 200 cases who adapted to plateau and the 106 cases of patients with HAPE susceptibility genes SNP locus, and got the key SNP loci of HAPE susceptibility genes. We maked the corresponding gene chip diagnostic kits.

  13. Letter to the Editor Reply to commentary by G. Sikri and S. Dua on the article "Correlation between single nucleotide polymorphisms in hypoxia-related genes and susceptibility to acute high-altitude pulmonary edema" published in Genetics and Molecular Research 14 (3): 11562-11572 to the letter published in Genet. Mol. Res. 14 (4): 15904-15905.

    PubMed

    Wu, L J

    2016-01-01

    The object in this study was a Han Chinese population in Lhasa, with 3658 m in altitude from Chengdu, which has 505 m in altitude by air. Within 24 to 48 h before the subjects arrived in the plateau, they completed a basic situation questionnaire, under the guidance of medical staff. Within 24 to 48 h after they reached the plateau, the subjects completed an acute plateau disease questionnaire. The diagnostic standard of HAPE and the diagnosis of acute plateau disease were adopted by the Lake Louise diagnostic standards in 1991 and the Chinese Medical Association promulgated the domestic diagnostic criteria on the Third National Plateau Medical Academic Seminar. Other diseases that cause acute symptoms of altitude sickness, such as plateau pulmonary edema, plateau cerebral edema, acute respiratory infections and neurosis, were excluded. According to the Lake Louise standard, questionnaire and symptom score values >3 points were diagnosed as HAPE. According to the national standard, the questionnaire and symptom score values >5 points were diagnosed as HAPE. At the present, morbidity of HAPE remains relatively high in China. The research shows that usually in the case of not taking preventive measures, according to the factors such as altitude, speed, and time of arrival, the incidence of HAPE is 30% to 90%. Epidemiological survey shows that HAPE happens at an altitude of 2500 m above the plateau. And an altitude of 3000 m above the plateau of China is occupied 1/6 of the total land area, the population of permanent residents is more than sixty million. We detected the 200 cases who adapted to plateau and the 106 cases of patients with HAPE susceptibility genes SNP locus, and got the key SNP loci of HAPE susceptibility genes. We maked the corresponding gene chip diagnostic kits. PMID:27050977

  14. Global assessment of high-altitude wind power

    NASA Astrophysics Data System (ADS)

    Archer, C. L.; Caldeira, K.

    2008-12-01

    Wind speed generally increases with altitude to the tropopause; hence, the power available in high-altitude winds is enormous, especially near the jet streams. We assess for the first time the available wind power resource worldwide at altitudes between 500 and 12,000 m. The highest wind power densities are found near 10,000 m over Japan and eastern China, the eastern coast of the United States, southern Australia, and north-eastern Africa. Below 1000 m, the best locations are the southern tip of South America, the coasts along the northern Pacific and Atlantic oceans, the central-eastern coast of Africa, and the north-eastern coast of South America. Because jet streams vary locally and seasonally, however, the high-altitude wind power resource is less steady than needed for baseload power. However, dynamically reaching the height with the highest winds, increasing the area covered with high-altitude devices, and using batteries for storage can effectively reduce intermittency. When high-altitude wind power devices are distributed uniformly throughout the entire atmosphere, numerical simulations show negligible effects on the global climate for low densities, but surface cooling, decreased precipitation, and greater sea ice cover for high densities.

  15. Convergent Evolution of Rumen Microbiomes in High-Altitude Mammals.

    PubMed

    Zhang, Zhigang; Xu, Dongming; Wang, Li; Hao, Junjun; Wang, Jinfeng; Zhou, Xin; Wang, Weiwei; Qiu, Qiang; Huang, Xiaodan; Zhou, Jianwei; Long, Ruijun; Zhao, Fangqing; Shi, Peng

    2016-07-25

    Studies of genetic adaptation, a central focus of evolutionary biology, most often focus on the host's genome and only rarely on its co-evolved microbiome. The Qinghai-Tibetan Plateau (QTP) offers one of the most extreme environments for the survival of human and other mammalian species. Yaks (Bos grunniens) and Tibetan sheep (T-sheep) (Ovis aries) have adaptations for living in this harsh high-altitude environment, where nomadic Tibetan people keep them primarily for food and livelihood [1]. Adaptive evolution affects energy-metabolism-related genes in a way that helps these ruminants live at high altitude [2, 3]. Herein, we report convergent evolution of rumen microbiomes for energy harvesting persistence in two typical high-altitude ruminants, yaks and T-sheep. Both ruminants yield significantly lower levels of methane and higher yields of volatile fatty acids (VFAs) than their low-altitude relatives, cattle (Bos taurus) and ordinary sheep (Ovis aries). Ultra-deep metagenomic sequencing reveals significant enrichment in VFA-yielding pathways of rumen microbial genes in high-altitude ruminants, whereas methanogenesis pathways show enrichment in the cattle metagenome. Analyses of RNA transcriptomes reveal significant upregulation in 36 genes associated with VFA transport and absorption in the ruminal epithelium of high-altitude ruminants. Our study provides novel insights into the contributions of microbiomes to adaptive evolution in mammals and sheds light on the biological control of greenhouse gas emissions from livestock enteric fermentation. PMID:27321997

  16. Apex high-altitude research sailplane mock-up

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This photo shows a mock-up of the Apex high-altitude research sailplane intended to be carried aloft by a balloon. The Apex High-Altitude Flight Experiment is expected to explore the aerodynamics of controlled flight at very high altitudes near 100,000 feet. The Apex will be hoisted aloft tail-first from Dryden by a large high-altitude balloon and released at about 110,000-feet altitude. As it gradually descends, its instrumentation will collect aerodynamic data. The remotely-piloted, semi-autonomous Apex will combine a modified ASC sailplane fuselage design with a new wing designed at the Massachusetts Institute of Technology. The wing will have a special airfoil designed for high subsonic speeds at extreme altitudes. A device extending behind the right wing is a 'wake rake,' which will measure aerodynamic drag behind a test section of the wing, while a rocket pack mounted beneath the fuselage will assist the Apex in transitioning to horizontal flight. Research flights were expected to begin in mid-1998, but a series of technical problems delayed them. In the spring of 1999, Apex entered mothball status. This continued for a year, and in the spring of 2000 NASA selected Apex as part of phase 1 of the Revolutionary Concepts effort.

  17. Decreased plasma soluble erythropoietin receptor in high-altitude excessive erythrocytosis and Chronic Mountain Sickness

    PubMed Central

    Macarlupú, José Luis; Anza-Ramírez, Cecilia; Corrales-Melgar, Daniela; Vizcardo-Galindo, Gustavo; Corante, Noemí; León-Velarde, Fabiola

    2014-01-01

    Excessive erythrocytosis (EE) is the hallmark of chronic mountain sickness (CMS), a prevalent syndrome in high-altitude Andean populations. Although hypoxemia represents its underlying stimulus, why some individuals develop EE despite having altitude-normal blood erythropoietin (Epo) concentration is still unclear. A soluble form of the Epo receptor (sEpoR) has been identified in human blood and competes directly for Epo with its membrane counterpart (mEpoR). Thus, reduced levels of circulating sEpoR could lead to higher Epo availability and ultimately to EE. We characterized the relationship between Epo and sEpoR, with hematocrit and hemoglobin concentration in healthy highlanders and CMS patients at 4,340 m in Cerro de Pasco, Peru. Our results show that EE patients show decreased plasma sEpoR levels and can be subdivided into two subgroups of normal and high plasma Epo concentration for the altitude of residence, with hemoglobin concentration rising exponentially with an increasing Epo-to-sEpoR ratio (Epo/sEpoR). Also, we showed that the latter varies as an inverse exponential function of arterial pulse O2 saturation. Our findings suggests that EE is strongly associated with higher Epo/sEpoR values, leading to elevated plasma Epo availability to bind mEpoR, and thereby a stronger stimulus for augmented erythropoiesis. Differences in the altitude normal and high Epo CMS patients with a progressively higher Epo/sEpoR supports the hypothesis of the existence of two genetically different subgroups suffering from EE and possibly different degrees of adaptation to chronic high-altitude hypoxia. PMID:25324511

  18. Decreased plasma soluble erythropoietin receptor in high-altitude excessive erythrocytosis and Chronic Mountain Sickness.

    PubMed

    Villafuerte, Francisco C; Macarlupú, José Luis; Anza-Ramírez, Cecilia; Corrales-Melgar, Daniela; Vizcardo-Galindo, Gustavo; Corante, Noemí; León-Velarde, Fabiola

    2014-12-01

    Excessive erythrocytosis (EE) is the hallmark of chronic mountain sickness (CMS), a prevalent syndrome in high-altitude Andean populations. Although hypoxemia represents its underlying stimulus, why some individuals develop EE despite having altitude-normal blood erythropoietin (Epo) concentration is still unclear. A soluble form of the Epo receptor (sEpoR) has been identified in human blood and competes directly for Epo with its membrane counterpart (mEpoR). Thus, reduced levels of circulating sEpoR could lead to higher Epo availability and ultimately to EE. We characterized the relationship between Epo and sEpoR, with hematocrit and hemoglobin concentration in healthy highlanders and CMS patients at 4,340 m in Cerro de Pasco, Peru. Our results show that EE patients show decreased plasma sEpoR levels and can be subdivided into two subgroups of normal and high plasma Epo concentration for the altitude of residence, with hemoglobin concentration rising exponentially with an increasing Epo-to-sEpoR ratio (Epo/sEpoR). Also, we showed that the latter varies as an inverse exponential function of arterial pulse O2 saturation. Our findings suggests that EE is strongly associated with higher Epo/sEpoR values, leading to elevated plasma Epo availability to bind mEpoR, and thereby a stronger stimulus for augmented erythropoiesis. Differences in the altitude normal and high Epo CMS patients with a progressively higher Epo/sEpoR supports the hypothesis of the existence of two genetically different subgroups suffering from EE and possibly different degrees of adaptation to chronic high-altitude hypoxia.

  19. Effects of high altitude and exercise on marksmanship.

    PubMed

    Tharion, W J; Hoyt, R W; Marlowe, B E; Cymerman, A

    1992-02-01

    The effects of exercise and high altitude (3,700 m to 4,300 m) on marksmanship accuracy and sighting time were quantified in 16 experienced marksmen. Subjects dry-fired a disabled rifle equipped with a laser-based system from a free-standing position. The 2.3-cm circular target was at a distance of 5 m. Marksmanship was assessed under the following conditions: 1) at rest at sea level; 2) immediately after a 21-km run/walk ascent from 1,800 m to 4,300 m elevation; 3) at rest during days 1 to 3 at altitude; 4) at rest during days 14 to 16 at altitude; and 5) immediately after a second ascent after 17 d at altitude. Exercise reduced marksmanship accuracy (p less than 0.05) but did not affect sighting time. Acute altitude exposure reduced marksmanship accuracy, and decreased sighting time (p less than 0.05). However, after residence at altitude, accuracy and sighting time at rest returned to sea level values. Exercise and acute altitude exposure had similar but independent detrimental effects on marksmanship. PMID:1546938

  20. Plants at high altitude exhibit higher component of alternative respiration.

    PubMed

    Kumar, Narinder; Vyas, Dhiraj; Kumar, Sanjay

    2007-01-01

    Total respiration, capacities of cytochrome (CytR) and alternative respiration (AR) were studied in two varieties of barley (Horedum vulgare) and wheat (Triticum aestivum) each and one variety of pea (Pisum sativum) at low (Palampur; 1300 m) and high altitudes (Kibber; 4200 m). Similar studies were carried out in naturally growing Rumex nepalensis and Trifoilum repenses at Palampur, Palchan (2250 m) and Marhi (3250 m). All the plants species exhibited lower CytR but significantly higher AR capacity at high altitude (HA) (72-1117% higher) as compared to those at low altitude (LA). Glycolytic product, pyruvate and tricarboxylic acid cycle intermediate, citrate increased with increase in altitude. While the role of these metabolites in relation to HA biology is discussed, significantly higher AR at HA is proposed to be an adaptive mechanism against the metabolic perturbations wherein it might act to lower reactive oxygen species and also provides metabolic homeostasis to plants under the environment of HA.

  1. The radiation protection problems of high altitude and space flight

    SciTech Connect

    Fry, R.J.M.

    1993-01-01

    This paper considers the radiation environment in aircraft at high altitudes and spacecraft in low earth orbit and in deep space and the factors that influence the dose equivalents. Altitude, latitude and solar cycle are the major influences for flights below the radiation belts. In deep space, solar cycle and the occurrence of solar particle events are the factors of influence. The major radiation effects of concern are cancer and infertility in males. In high altitude aircraft the radiation consists mainly of protons and neutrons, with neutrons contributing about half the equivalent dose. The average dose rate at altitudes of transcontinental flights that approach the polar regions are greater by a factor of about 2.5 than on routes at low latitudes. Current estimates of does to air crews suggest they are well within the ICRP (1990) recommended dose limits for radiation workers.

  2. The radiation protection problems of high altitude and space flight

    SciTech Connect

    Fry, R.J.M.

    1993-04-01

    This paper considers the radiation environment in aircraft at high altitudes and spacecraft in low earth orbit and in deep space and the factors that influence the dose equivalents. Altitude, latitude and solar cycle are the major influences for flights below the radiation belts. In deep space, solar cycle and the occurrence of solar particle events are the factors of influence. The major radiation effects of concern are cancer and infertility in males. In high altitude aircraft the radiation consists mainly of protons and neutrons, with neutrons contributing about half the equivalent dose. The average dose rate at altitudes of transcontinental flights that approach the polar regions are greater by a factor of about 2.5 than on routes at low latitudes. Current estimates of does to air crews suggest they are well within the ICRP (1990) recommended dose limits for radiation workers.

  3. Effect of hypoxia by intermittent altitude exposure on semen characteristics and testicular morphology of male rhesus monkeys

    NASA Astrophysics Data System (ADS)

    Saxena, D. K.

    1995-09-01

    Semen characteristics and testicular morphology of rhesus monkeys were studied on exposure to a simulated high altitude of 4411 m for 21 days. There was a partially reversible decrease in the semen volume, sperm count and sperm motility, as well as an elevation of pH and fructose concentration. These changes were associated with degeneration of the germinal epithelium and spermatogenic arrest at the end of third week of exposure which had not recovered even 3 weeks after the exposure.

  4. Long-Term Chronic Intermittent Hypobaric Hypoxia in Rats Causes an Imbalance in the Asymmetric Dimethylarginine/Nitric Oxide Pathway and ROS Activity: A Possible Synergistic Mechanism for Altitude Pulmonary Hypertension?

    PubMed Central

    Lüneburg, Nicole; Siques, Patricia; Brito, Julio; Arriaza, Karem; Pena, Eduardo; Klose, Hans; Leon-Velarde, Fabiola; Böger, Rainer H.

    2016-01-01

    Chronic intermittent hypoxia (CIH) and chronic hypoxia (CH) are associated with high-altitude pulmonary hypertension (HAPH). Asymmetric dimethylarginine (ADMA), a NO synthase (NOS) inhibitor, may contribute to HAPH. This study assessed changes in the ADMA/NO pathway and the underlying mechanisms in rat lungs following exposure to CIH or CH simulated in a hypobaric chamber at 428 Torr. Twenty-four adult Wistar rats were randomly assigned to three groups: CIH2x2 (2 days of hypoxia/2 days of normoxia), CH, and NX (permanent normoxia), for 30 days. All analyses were performed in whole lung tissue. L-Arginine and ADMA were analyzed using LC-MS/MS. Under both hypoxic conditions right ventricular hypertrophy was observed (p < 0.01) and endothelial NOS mRNA increased (p < 0.001), but the phosphorylated/nonphosphorylated vasodilator-stimulated phosphoprotein (VASP) ratio was unchanged. ADMA increased (p < 0.001), whereas dimethylarginine dimethylaminohydrolase (DDAH) activity decreased only under CH (p < 0.05). Although arginase activity increased (p < 0.001) and L-arginine exhibited no changes, the L-arginine/ADMA ratio decreased significantly (p < 0.001). Moreover, NOX4 expression increased only under CH (p < 0.01), but malondialdehyde (MDA) increased (up to 2-fold) equally in CIH2x2 and CH (p < 0.001). Our results suggest that ADMA and oxidative stress likely reduce NO bioavailability under altitude hypoxia, which implies greater pulmonary vascular reactivity and tone, despite the more subdued effects observed under CIH. PMID:27313889

  5. SHARP: Subsonic High Altitude Research Platform

    NASA Technical Reports Server (NTRS)

    Beals, Todd; Burton, Craig; Cabatan, Aileen; Hermano, Christine; Jones, Tom; Lee, Susan; Radloff, Brian

    1991-01-01

    The Universities Space Research Association is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to satisfy four mission profiles. Mission one is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.mi. at 100,000 ft with a 2500 lb payload. The second mission is also a polar mission, with an altitude of 70,000 ft and an increased payload of 4000 lbs. For the third mission, the aircraft will takeoff at NASA Ames, cruise at 100,000 ft carrying a 2500 lb payload, and land at Puerto Montt, Chile. The final mission requires the aircraft to take off at NASA Ames, cruise at 100,000 ft with a 1000 lb payload, make an excursion to 120,000 ft, and land at Howard AFB, Panama. Three missions require that a subsonic Mach number be maintained due to constraints imposed by the air sampling equipment. The aircraft need not be manned for all four missions. Three aircraft configurations have been determined to be the most suitable for meeting the above requirements. In the event that a requirement cannot be obtained within the given constraints, recommendations for proposal modifications are given.

  6. The evidence for hereditary factors contributing to high altitude adaptation in Andean natives: a review.

    PubMed

    Rupert, J L; Hochachka, P W

    2001-01-01

    Humans have occupied the high plateaus and mountain valleys of the Andes and the Himalayas for thousands of years. Although sea level natives can, and often do, travel in these rarefied reaches, there is little doubt that natives born and raised in the "thin" air are better equipped to deal with the reduced availability of oxygen at altitude. What fraction of the hypoxia defense response of high altitude native populations is due to developmental adaptations acquired during growth and what fraction is due to a genetic component reflecting the effects of selective transmission of beneficial genetic variants through hundreds of generations of antecedents is as yet unresolved. This paper summarizes some of the studies that have been undertaken to address this issue in Andean indigenous populations, primarily with respect to those adaptations thought to be involved in the uptake, distribution and utilization of oxygen in children and adults. Specifically, it focuses on changes in chest morphology, pulmonary function, metabolism and hematology. Space constraints preclude extending this review to the large body of literature concerning prenatal and maternal adaptations although this critical stage in development has likely been subject to significant selective pressures. It is apparent that both nature and nurture influence the acquisition of a high altitude phenotype in humans and while there is some evidence for genetic adaptation in Andean highlanders, it is evident that these characteristics are expressed in concert with substantial environment-dependent developmental adjustments.

  7. Periodic breathing and oxygen supplementation in Chilean miners at high altitude (4200m).

    PubMed

    Moraga, Fernando A; Jiménez, Daniel; Richalet, Jean Paul; Vargas, Manuel; Osorio, Jorge

    2014-11-01

    Our objective was to determine the nocturnal ventilatory pattern and characterize the effect of oxygen enrichment on nocturnal ventilatory pattern and sleep quality in miners exposed to intermittent hypobaric hypoxia at 4200m. A total of 16 acclimatized miners were studied. Nocturnal ventilatory pattern (plethysmographic inductance), arterial oxygen saturation and heart rate (pulse oximetry) were performed in 9/16 subjects. Sleep quality at high altitude was assessed by self-questionnaires in 16/16 subjects. All measurements were performed during at least 7h of sleep. Subjects were studied while sleeping at high altitude without (control, C) and with oxygen supplementation (FiO2=0.25, treated, T). Periodic breathing (%) C: 25±18 vs T: 6.6±5.6 (p<0.05), apneas index (no./h) C: 34.9±24.1 vs T: 8.5±6.8 (p<0.05); and sleep quality C: 17.8±3.4 vs T: 12.1±2.2 (p<0.0001) were evaluated. In conclusion, periodic breathing with apneas was present in miners exposed to high altitude for 1 to 4 years and was reduced by treatment with supplementary oxygen. PMID:25219448

  8. Wilderness medicine at high altitude: recent developments in the field.

    PubMed

    Shah, Neeraj M; Hussain, Sidra; Cooke, Mark; O'Hara, John P; Mellor, Adrian

    2015-01-01

    Travel to high altitude is increasingly popular. With this comes an increased incidence of high-altitude illness and therefore an increased need to improve our strategies to prevent and accurately diagnose these. In this review, we provide a summary of recent advances of relevance to practitioners who may be advising travelers to altitude. Although the Lake Louise Score is now widely used as a diagnostic tool for acute mountain sickness (AMS), increasing evidence questions the validity of doing so, and of considering AMS as a single condition. Biomarkers, such as brain natriuretic peptide, are likely correlating with pulmonary artery systolic pressure, thus potential markers of the development of altitude illness. Established drug treatments include acetazolamide, nifedipine, and dexamethasone. Drugs with a potential to reduce the risk of developing AMS include nitrate supplements, propagators of nitric oxide, and supplemental iron. The role of exercise in the development of altitude illness remains hotly debated, and it appears that the intensity of exercise is more important than the exercise itself. Finally, despite copious studies demonstrating the value of preacclimatization in reducing the risk of altitude illness and improving performance, an optimal protocol to preacclimatize an individual remains elusive. PMID:26445563

  9. Wilderness medicine at high altitude: recent developments in the field

    PubMed Central

    Shah, Neeraj M; Hussain, Sidra; Cooke, Mark; O’Hara, John P; Mellor, Adrian

    2015-01-01

    Travel to high altitude is increasingly popular. With this comes an increased incidence of high-altitude illness and therefore an increased need to improve our strategies to prevent and accurately diagnose these. In this review, we provide a summary of recent advances of relevance to practitioners who may be advising travelers to altitude. Although the Lake Louise Score is now widely used as a diagnostic tool for acute mountain sickness (AMS), increasing evidence questions the validity of doing so, and of considering AMS as a single condition. Biomarkers, such as brain natriuretic peptide, are likely correlating with pulmonary artery systolic pressure, thus potential markers of the development of altitude illness. Established drug treatments include acetazolamide, nifedipine, and dexamethasone. Drugs with a potential to reduce the risk of developing AMS include nitrate supplements, propagators of nitric oxide, and supplemental iron. The role of exercise in the development of altitude illness remains hotly debated, and it appears that the intensity of exercise is more important than the exercise itself. Finally, despite copious studies demonstrating the value of preacclimatization in reducing the risk of altitude illness and improving performance, an optimal protocol to preacclimatize an individual remains elusive. PMID:26445563

  10. Resting pulmonary haemodynamics and shunting: a comparison of sea-level inhabitants to high altitude Sherpas.

    PubMed

    Foster, Glen E; Ainslie, Philip N; Stembridge, Mike; Day, Trevor A; Bakker, Akke; Lucas, Samuel J E; Lewis, Nia C S; MacLeod, David B; Lovering, Andrew T

    2014-03-15

    The incidence of blood flow through intracardiac shunt and intrapulmonary arteriovenous anastomoses (IPAVA) may differ between Sherpas permanently residing at high altitude (HA) and sea-level (SL) inhabitants as a result of evolutionary pressure to improve gas exchange and/or resting pulmonary haemodynamics. To test this hypothesis we compared sea-level inhabitants at SL (SL-SL; n = 17), during acute isocapnic hypoxia (SL-HX; n = 7) and following 3 weeks at 5050 m (SL-HA; n = 8 non-PFO subjects) to Sherpas at 5050 m (n = 14). SpO2, heart rate, pulmonary artery systolic pressure (PASP) and cardiac index (Qi) were measured during 5 min of room air breathing at SL and HA, during 20 min of isocapnic hypoxia (SL-HX; PETO2 = 47 mmHg) and during 5 min of hyperoxia (FIO2 = 1.0; Sherpas only). Intracardiac shunt and IPAVA blood flow was evaluated by agitated saline contrast echocardiography. Although PASP was similar between groups at HA (Sherpas: 30.0 ± 6.0 mmHg; SL-HA: 32.7 ± 4.2 mmHg; P = 0.27), it was greater than SL-SL (19.4 ± 2.1 mmHg; P < 0.001). The proportion of subjects with intracardiac shunt was similar between groups (SL-SL: 41%; Sherpas: 50%). In the remaining subjects, IPAVA blood flow was found in 100% of subjects during acute isocapnic hypoxia at SL, but in only 4 of 7 Sherpas and 1 of 8 SL-HA subjects at rest. In conclusion, differences in resting pulmonary vascular regulation, intracardiac shunt and IPAVA blood flow do not appear to account for any adaptation to HA in Sherpas. Despite elevated pulmonary pressures and profound hypoxaemia, IPAVA blood flow in all subjects at HA was lower than expected compared to acute normobaric hypoxia.

  11. Long-Term Exposure to High Altitude Affects Conflict Control in the Conflict-Resolving Stage.

    PubMed

    Ma, Hailin; Wang, Yan; Wu, Jianhui; Wang, Baoxi; Guo, Shichun; Luo, Ping; Han, Buxin

    2015-01-01

    The neurocognitive basis of the effect of long-term high altitude exposure on conflict control is unclear. Event related potentials (ERPs) were recorded in a flanker task to investigate the influence of high altitude on conflict control in the high-altitude group (who had lived at high altitude for three years but were born at low altitude) and the low-altitude group (living in low altitude only). Although altitude effect was not significant at the behavioral level, ERPs showed cognitive conflict modulation. The interaction between group and trial type was significant: P3 amplitude was greater in the low-altitude group than in the high-altitude group in the incongruent trial. This result suggests that long-term exposure to high altitude affects conflict control in the conflict-resolving stage, and that attentional resources are decreased to resist the conflict control in the high-altitude group.

  12. Long-Term Exposure to High Altitude Affects Conflict Control in the Conflict-Resolving Stage

    PubMed Central

    Wu, Jianhui; Wang, Baoxi; Guo, Shichun; Luo, Ping; Han, Buxin

    2015-01-01

    The neurocognitive basis of the effect of long-term high altitude exposure on conflict control is unclear. Event related potentials (ERPs) were recorded in a flanker task to investigate the influence of high altitude on conflict control in the high-altitude group (who had lived at high altitude for three years but were born at low altitude) and the low-altitude group (living in low altitude only). Although altitude effect was not significant at the behavioral level, ERPs showed cognitive conflict modulation. The interaction between group and trial type was significant: P3 amplitude was greater in the low-altitude group than in the high-altitude group in the incongruent trial. This result suggests that long-term exposure to high altitude affects conflict control in the conflict-resolving stage, and that attentional resources are decreased to resist the conflict control in the high-altitude group. PMID:26671280

  13. Economy of locomotion in high-altitude Tibetan migrants exposed to normoxia

    PubMed Central

    Marconi, Claudio; Marzorati, Mauro; Sciuto, Daniele; Ferri, Alessandra; Cerretelli, Paolo

    2005-01-01

    High-altitude Tibetans undergo a pattern of adaptations to chronic hypoxia characterized, among others, by a more efficient aerobic performance compared with acclimatized lowlanders. To test whether such changes may persist upon descent to moderate altitude, oxygen uptake of 17 male Tibetan natives lifelong residents at 3500–4500 m was assessed within 1 month upon migration to 1300 m. Exercise protocols were: 5 min treadmill walking at 6 km h−1 on increasing inclines from +5 to +15% and 5 min running at 10 km h−1 on a +5% grade. The data (mean ± s.e.m.) were compared with those obtained on Nepali lowlanders. When walking on +10, +12.5 and +15% inclines, net of Tibetans was 25.2 ± 0.7, 29.1 ± 1.1 and 31.3 ± 0.9 ml kg−1 min−1, respectively, i.e. 8, 10 and 13% less (P < 0.05) than that of Nepali. At the end of the heaviest load, blood lactate concentration was lower in Tibetans than in Nepali (6.0 ± 0.9 versus 8.9 ± 0.6 mm; P < 0.05). During running, of Tibetans was 35.1 ± 0.8 versus 39.3 ± 0.7 ml kg−1 min−1 (i.e. 11% less; P < 0.01). In conclusion, during submaximal walking and running at 1300 m, Tibetans are still characterized by lower aerobic energy expenditure than control subjects that is not accounted for by differences in mechanical power output and/or compensated for by anaerobic glycolysis. These findings indicate that chronic hypoxia induces metabolic adaptations whose underlying mechanisms still need to be elucidated, that persist for at least 1 month upon descent to moderate altitude. PMID:16179365

  14. Periodic Breathing and Behavioral Awakenings at High Altitude.

    PubMed

    Shogilev, Daniel J; Tanner, John B; Chang, Yuchiao; Harris, N Stuart

    2015-01-01

    Objectives. To study the relationship between nocturnal periodic breathing episodes and behavioral awakenings at high altitude. Methods. Observational study. It is 6-day ascent of 4 healthy subjects from Besisahar (760 meters) to Manang (3540 meters) in Nepal in March 2012. A recording pulse oximeter was worn by each subject to measure their oxygen saturation and the presence of periodic breathing continuously through the night. An actigraph was simultaneously worn in order to determine nocturnal behavioral awakenings. There were no interventions. Results. 187-hour sleep at high altitude was analyzed, and of this, 145 hours (78%) had at least one PB event. At high altitude, 10.5% (95% CI 6.5-14.6%) of total sleep time was spent in PB while 15 out of 50 awakenings (30%, 95% CI: 18-45%) occurring at high altitudes were associated with PB (P < 0.001). Conclusions. Our data reveals a higher than expected number of behavioral awakenings associated with PB compared to what would be expected by chance. This suggests that PB likely plays a role in behavioral awakenings at high altitude. PMID:26483979

  15. Can my patient with CVD travel to high altitude?

    PubMed

    Hoigné, Philipp; Gibbs, J Simon R

    2013-04-01

    Patients with borderline health should consult a physican before travelling to altitude. The physician will need to know the duration of the trip, ascent profile and how much exercise the patient plans to undertake. The presence of comorbid diseases which reduce oxygenation and ventilation should also be taken into account. Every patient must be assessed on an individual basis, there are no clinical investigations which reliably predict outcome at altitude. Complex cases may require advice from the patient's cardiologist. Travelling from sea level to an altitude of 2,500 m causes a 20% reduction in the partial pressure of inspired oxygen. There is an initial net increase in myocardial oxygen consumption during the first 3-5 days, this then falls as cardiac output on exercise is reduced. During this time patients with angina pectoris may become symptomatic at a lower level of exercise than at sea level and should be advised to reduce their activity. After five days at 2,500 m, the exertion threshold returns to sea level values. Patients should not travel to high altitude immediately after an acute coronary syndrome. Most patients with stable coronary artery disease with a sufficiently high exercise capacity at sea level can go as high as 3,000-3,500 m with only a minimally increased risk. Patients with heart failure have a greater reduction in exercise performance than healthy people at altitude. Patients with mild to moderately impaired systolic LVF and mild symptoms may travel up to 3,000-3,500 m for a day trip. Patients with poorly controlled hypertension should not travel to high altitude. Those with controlled hypertension should consider taking their own blood pressure during a stay at altitude.

  16. Effectiveness of intermittent training in hypoxia combined with live high/train low.

    PubMed

    Robertson, Eileen Y; Saunders, Philo U; Pyne, David B; Gore, Christopher J; Anson, Judith M

    2010-09-01

    Elite athletes often undertake altitude training to improve sea-level athletic performance, yet the optimal methodology has not been established. A combined approach of live high/train low plus train high (LH/TL+TH) may provide an additional training stimulus to enhance performance gains. Seventeen male and female middle-distance runners with maximal aerobic power (VO2max) of 65.5 +/- 7.3 mL kg(-1) min(-1) (mean +/- SD) trained on a treadmill in normobaric hypoxia for 3 weeks (2,200 m, 4 week(-1)). During this period, the train high (TH) group (n = 9) resided near sea-level (approximately 600 m) while the LH/TL+TH group (n = 8) stayed in normobaric hypoxia (3,000 m) for 14 hours day(-1). Changes in 3-km time trial performance and physiological measures including VO2max, running economy and haemoglobin mass (Hb(mass)) were assessed. The LH/TL+TH group substantially improved VO2max (4.8%; +/-2.8%, mean; +/-90% CL), Hb(mass) (3.6%; +/-2.4%) and 3-km time trial performance (-1.1%; +/-1.0%) immediately post-altitude. There was no substantial improvement in time trial performance 2 weeks later. The TH group substantially improved VO2max (2.2%; +/-1.8%), but had only trivial changes in Hb(mass) and 3-km time-trial performance. Compared with TH, combined LH/TL+TH substantially improved VO2max (2.6%; +/-3.2%), Hb(mass) (4.3%; +/-3.2%), and time trial performance (-0.9%; +/-1.4%) immediately post-altitude. LH/TL+TH elicited greater enhancements in physiological capacities compared with TH, however, the transfer of benefits to time-trial performance was more variable.

  17. AltitudeOmics: Resetting of Cerebrovascular CO2 Reactivity Following Acclimatization to High Altitude.

    PubMed

    Fan, Jui-Lin; Subudhi, Andrew W; Duffin, James; Lovering, Andrew T; Roach, Robert C; Kayser, Bengt

    2015-01-01

    Previous studies reported enhanced cerebrovascular CO2 reactivity upon ascent to high altitude using linear models. However, there is evidence that this response may be sigmoidal in nature. Moreover, it was speculated that these changes at high altitude are mediated by alterations in acid-base buffering. Accordingly, we reanalyzed previously published data to assess middle cerebral blood flow velocity (MCAv) responses to modified rebreathing at sea level (SL), upon ascent (ALT1) and following 16 days of acclimatization (ALT16) to 5260 m in 21 lowlanders. Using sigmoid curve fitting of the MCAv responses to CO2, we found the amplitude (95 vs. 129%, SL vs. ALT1, 95% confidence intervals (CI) [77, 112], [111, 145], respectively, P = 0.024) and the slope of the sigmoid response (4.5 vs. 7.5%/mmHg, SL vs. ALT1, 95% CIs [3.1, 5.9], [6.0, 9.0], respectively, P = 0.026) to be enhanced at ALT1, which persisted with acclimatization at ALT16 (amplitude: 177, 95% CI [139, 215], P < 0.001; slope: 10.3%/mmHg, 95% CI [8.2, 12.5], P = 0.003) compared to SL. Meanwhile, the sigmoidal response midpoint was unchanged at ALT1 (SL: 36.5 mmHg; ALT1: 35.4 mmHg, 95% CIs [34.0, 39.0], [33.1, 37.7], respectively, P = 0.982), while it was reduced by ~7 mmHg at ALT16 (28.6 mmHg, 95% CI [26.4, 30.8], P = 0.001 vs. SL), indicating leftward shift of the cerebrovascular CO2 response to a lower arterial partial pressure of CO2 (PaCO2) following acclimatization to altitude. Sigmoid fitting revealed a leftward shift in the midpoint of the cerebrovascular response curve which could not be observed with linear fitting. These findings demonstrate that there is resetting of the cerebrovascular CO2 reactivity operating point to a lower PaCO2 following acclimatization to high altitude. This cerebrovascular resetting is likely the result of an altered acid-base buffer status resulting from prolonged exposure to the severe hypocapnia associated with ventilatory acclimatization to high altitude.

  18. AltitudeOmics: Resetting of Cerebrovascular CO2 Reactivity Following Acclimatization to High Altitude

    PubMed Central

    Fan, Jui-Lin; Subudhi, Andrew W.; Duffin, James; Lovering, Andrew T.; Roach, Robert C.; Kayser, Bengt

    2016-01-01

    Previous studies reported enhanced cerebrovascular CO2 reactivity upon ascent to high altitude using linear models. However, there is evidence that this response may be sigmoidal in nature. Moreover, it was speculated that these changes at high altitude are mediated by alterations in acid-base buffering. Accordingly, we reanalyzed previously published data to assess middle cerebral blood flow velocity (MCAv) responses to modified rebreathing at sea level (SL), upon ascent (ALT1) and following 16 days of acclimatization (ALT16) to 5260 m in 21 lowlanders. Using sigmoid curve fitting of the MCAv responses to CO2, we found the amplitude (95 vs. 129%, SL vs. ALT1, 95% confidence intervals (CI) [77, 112], [111, 145], respectively, P = 0.024) and the slope of the sigmoid response (4.5 vs. 7.5%/mmHg, SL vs. ALT1, 95% CIs [3.1, 5.9], [6.0, 9.0], respectively, P = 0.026) to be enhanced at ALT1, which persisted with acclimatization at ALT16 (amplitude: 177, 95% CI [139, 215], P < 0.001; slope: 10.3%/mmHg, 95% CI [8.2, 12.5], P = 0.003) compared to SL. Meanwhile, the sigmoidal response midpoint was unchanged at ALT1 (SL: 36.5 mmHg; ALT1: 35.4 mmHg, 95% CIs [34.0, 39.0], [33.1, 37.7], respectively, P = 0.982), while it was reduced by ~7 mmHg at ALT16 (28.6 mmHg, 95% CI [26.4, 30.8], P = 0.001 vs. SL), indicating leftward shift of the cerebrovascular CO2 response to a lower arterial partial pressure of CO2 (PaCO2) following acclimatization to altitude. Sigmoid fitting revealed a leftward shift in the midpoint of the cerebrovascular response curve which could not be observed with linear fitting. These findings demonstrate that there is resetting of the cerebrovascular CO2 reactivity operating point to a lower PaCO2 following acclimatization to high altitude. This cerebrovascular resetting is likely the result of an altered acid-base buffer status resulting from prolonged exposure to the severe hypocapnia associated with ventilatory acclimatization to high altitude. PMID:26779030

  19. High-Altitude, Long-Endurance Airships for Coastal Surveillance

    NASA Technical Reports Server (NTRS)

    Dolce, James L.; Collozza, Anthony

    2005-01-01

    A high altitude solar powered airship provides the ability to carry large payloads to high altitudes and remain on station for extended periods of time. This study examines applications and background of this type of concept vehicle, reviews the history of high altitude flight and provides a point design analysis. The capabilities and limitations of the airship are demonstrated and possible solutions are proposed. Factors such as time of year, latitude, wind speeds, and payload are considered in establishing the capabilities of the airship. East and west coast operation is evaluated. The key aspect to success of this type of airship is the design and operation of the propulsion and power system. A preliminary propulsion/power system design was produced based on a regenerative fuel cell energy storage system and solar photovoltaic array for energy production. Results on power system requirements for year long operation is presented.

  20. Anthropometric comparison between high- and low-altitude Saudi Arabians.

    PubMed

    Khalid, M

    1995-01-01

    Measurements of weight, height, mid-upper arm circumference, mid-upper arm muscle circumference and skinfold thickness over the triceps region were made in 437 high-altitude residents (3150m above sea level) aged 16-60 years and 468 low-altitude residents (500 m above sea level) aged 16-60 years in southern Saudi Arabia. Compared with low-altitude residents, high-altitude residents were found to be significantly heavier and taller, but to have nearly similar mid-upper arm circumference, mid-upper arm muscle circumference and triceps skinfold thickness. Estimates of body fat have been made from the triceps skinfold measurements. No significant difference in the percentage of fat was detected between high- and low-altitude residents. When fat mass (kg) and fat mass index (fat mass (kg)/height in m2) were considered, similar trends were found between highland and lowland men only. Highland women showed significantly higher fat mass and fat mass index when compared with lowland women. These differences in physique between highland and lowland residents of southern Saudi Arabia may be attributed to the effect of environmental factors, possibly the hot climate and parasitic infections prevalent in lowland areas, in addition to the higher physical activity observed in lowland women.

  1. Joseph Barcroft's studies of high-altitude physiology.

    PubMed

    West, John B

    2013-10-15

    Joseph Barcroft (1872-1947) was an eminent British physiologist who made contributions to many areas. Some of his studies at high altitude and related topics are reviewed here. In a remarkable experiment he spent 6 days in a small sealed room while the oxygen concentration of the air gradually fell, simulating an ascent to an altitude of nearly 5,500 m. The study was prompted by earlier reports by J. S. Haldane that the lung secreted oxygen at high altitude. Barcroft tested this by having blood removed from an exposed radial artery during both rest and exercise. No evidence for oxygen secretion was found, and the combination of 6 days incarceration and the loss of an artery was heroic. To obtain more data, Barcroft organized an expedition to Cerro de Pasco, Peru, altitude 4,300 m, that included investigators from both Cambridge, UK and Harvard. Again oxygen secretion was ruled out. The protocol included neuropsychometric measurements, and Barcroft famously concluded that all dwellers at high altitude are persons of impaired physical and mental powers, an assertion that has been hotly debated. Another colorful experiment in a low-pressure chamber involved reducing the pressure below that at the summit of Mt. Everest but giving the subjects 100% oxygen to breathe while exercising as a climber would on Everest. The conclusion was that it would be possible to reach the summit while breathing 100% oxygen. Barcroft was exceptional for his self-experimentation under hazardous conditions.

  2. Disturbances in Maternal Steroidogenesis and Appearance of Intrauterine Growth Retardation at High-Altitude Environments Are Established from Early Pregnancy. Effects of Treatment with Antioxidant Vitamins.

    PubMed

    Parraguez, Victor H; Mamani, Sandra; Cofré, Eileen; Castellaro, Giorgio; Urquieta, Bessie; De Los Reyes, Mónica; Astiz, Susana; Gonzalez-Bulnes, Antonio

    2015-01-01

    Pregnancies at high-altitudes are influenced by hypoxia and oxidative stress and frequently affected by IUGR. However, a common thought is that early pregnant women visiting altitude have no major complications for gestation development, since IUGR is developed during the second half of pregnancy. Thus, using a well-characterized sheep-model, we aimed to determine whether long- and/or short-term exposure to high-altitude may affect maternal steroidogenesis and therefore embryo-fetal growth from conception. The second aim was to differentiate the relative role of hypoxia and oxidative stress by assessing the effects of supplementation with antioxidant agents during this early-pregnancy stage, which were previously found to be useful to prevent IUGR. The results indicate that both long- and short-term exposure to high-altitude causes disturbances in maternal ovarian steroidogenesis and negatively affects embryo-fetal growth already during the very early stages of gestation, with the consequences being even worsened in newcomers to high-altitude. The supply of antioxidant during this period only showed discrete effects for preventing IUGR. In conclusion, the present study gives a warning for clinicians about the risks for early-pregnant women when visiting high-altitude regions and suggests the need for further studies on the effects of the length of exposure and on the interaction of the exposure with the pregnancy stage. PMID:26560325

  3. Disturbances in Maternal Steroidogenesis and Appearance of Intrauterine Growth Retardation at High-Altitude Environments Are Established from Early Pregnancy. Effects of Treatment with Antioxidant Vitamins.

    PubMed

    Parraguez, Victor H; Mamani, Sandra; Cofré, Eileen; Castellaro, Giorgio; Urquieta, Bessie; De Los Reyes, Mónica; Astiz, Susana; Gonzalez-Bulnes, Antonio

    2015-01-01

    Pregnancies at high-altitudes are influenced by hypoxia and oxidative stress and frequently affected by IUGR. However, a common thought is that early pregnant women visiting altitude have no major complications for gestation development, since IUGR is developed during the second half of pregnancy. Thus, using a well-characterized sheep-model, we aimed to determine whether long- and/or short-term exposure to high-altitude may affect maternal steroidogenesis and therefore embryo-fetal growth from conception. The second aim was to differentiate the relative role of hypoxia and oxidative stress by assessing the effects of supplementation with antioxidant agents during this early-pregnancy stage, which were previously found to be useful to prevent IUGR. The results indicate that both long- and short-term exposure to high-altitude causes disturbances in maternal ovarian steroidogenesis and negatively affects embryo-fetal growth already during the very early stages of gestation, with the consequences being even worsened in newcomers to high-altitude. The supply of antioxidant during this period only showed discrete effects for preventing IUGR. In conclusion, the present study gives a warning for clinicians about the risks for early-pregnant women when visiting high-altitude regions and suggests the need for further studies on the effects of the length of exposure and on the interaction of the exposure with the pregnancy stage.

  4. Disturbances in Maternal Steroidogenesis and Appearance of Intrauterine Growth Retardation at High-Altitude Environments Are Established from Early Pregnancy. Effects of Treatment with Antioxidant Vitamins

    PubMed Central

    Parraguez, Victor H.; Mamani, Sandra; Cofré, Eileen; Castellaro, Giorgio; Urquieta, Bessie; De los Reyes, Mónica; Astiz, Susana; Gonzalez-Bulnes, Antonio

    2015-01-01

    Pregnancies at high-altitudes are influenced by hypoxia and oxidative stress and frequently affected by IUGR. However, a common thought is that early pregnant women visiting altitude have no major complications for gestation development, since IUGR is developed during the second half of pregnancy. Thus, using a well-characterized sheep-model, we aimed to determine whether long- and/or short-term exposure to high-altitude may affect maternal steroidogenesis and therefore embryo-fetal growth from conception. The second aim was to differentiate the relative role of hypoxia and oxidative stress by assessing the effects of supplementation with antioxidant agents during this early-pregnancy stage, which were previously found to be useful to prevent IUGR. The results indicate that both long- and short-term exposure to high-altitude causes disturbances in maternal ovarian steroidogenesis and negatively affects embryo-fetal growth already during the very early stages of gestation, with the consequences being even worsened in newcomers to high-altitude. The supply of antioxidant during this period only showed discrete effects for preventing IUGR. In conclusion, the present study gives a warning for clinicians about the risks for early-pregnant women when visiting high-altitude regions and suggests the need for further studies on the effects of the length of exposure and on the interaction of the exposure with the pregnancy stage. PMID:26560325

  5. [Medical certification for high altitude travel and scuba diving].

    PubMed

    Wuillemin, Timothée; Dos Santos Bragança, Angel; Ziltener, Jean-Luc; Berney, Jean-Yves; Lanier, Cédric

    2014-09-24

    People are more and more looking for adventures and discovery of unusual locations. Journeys to high altitude and scuba diving are part of these activities and their access has become easier for a lot of people not necessarily experienced with their dangers. The general practitioner will have to be able to deliver some advices and recommendations to his patients about the risks related to these activities and their ability to practice them. He will also have to deliver some certificates of medical fitness to dive. This paper proposes a brief review of the most important medical aspects to know about high altitude and scuba diving.

  6. [Medical certification for high altitude travel and scuba diving].

    PubMed

    Wuillemin, Timothée; Dos Santos Bragança, Angel; Ziltener, Jean-Luc; Berney, Jean-Yves; Lanier, Cédric

    2014-09-24

    People are more and more looking for adventures and discovery of unusual locations. Journeys to high altitude and scuba diving are part of these activities and their access has become easier for a lot of people not necessarily experienced with their dangers. The general practitioner will have to be able to deliver some advices and recommendations to his patients about the risks related to these activities and their ability to practice them. He will also have to deliver some certificates of medical fitness to dive. This paper proposes a brief review of the most important medical aspects to know about high altitude and scuba diving. PMID:25369697

  7. Effect of phosphate supplementation on oxygen delivery at high altitude

    NASA Astrophysics Data System (ADS)

    Jain, S. C.; Singh, M. V.; Rawal, S. B.; Sharma, V. M.; Divekar, H. M.; Tyagi, A. K.; Panwar, M. R.; Swamy, Y. V.

    1987-09-01

    In the present communication, effect of low doses of phosphate supplementation on short-term high altitude adaptation has been examined. Studies were carried out in 36 healthy, male, sea-level residents divided in a double blind fashion into drug and placebo treated groups. 3.2 mmol of phosphate were given orally to each subject of the drug treated group once a day for 4 days on arrival at an altitude of 3,500 m. Sequential studies were done in the subjects in both groups on the 3rd, 7th, 14th and 21st day of their altitude stay. Haemoglobin, haematocrit, erythrocyte and reticulocyte counts increased to the similar extent in both groups. Blood pH, pO2 and adenosine tri-phosphate (ATP) did not differ between the two groups. On 3rd day of the altitude stay, inorganic phosphate and 2,3-diphosphoglycerate (2,3 DPG) levels in the drug treated group increased significantly as compared to the placebo group. No significant difference in inorganic phosphate and 2,3 DPG was observed later on in the two groups. Psychological and clinical tests also indicated that the drug treated subjects felt better as compared to the placebo treated subjects. The present study suggests that low doses of phosphate increases circulating 2,3-DPG concentration which in turn brings about beneficial effect towards short term high altitude adaptation.

  8. Calibration of solar cells using high-altitude aircraft.

    NASA Technical Reports Server (NTRS)

    Brandhorst, H. W., Jr.

    1971-01-01

    A high altitude airplane has been used to obtain the outer space short circuit current of solar cells. The solar cells are mounted in a collimating tube and are measured at approximately 5000 foot intervals between 12,000 and 47,000 feet. The air mass is calculated for each altitude using the standard formula and the resulting curve is extrapolated to air mass zero. The effects on the solar cell output of a haze layer located at the tropopause has been observed. It is necessary to fly above this layer to ensure accurate results. Airplane calibrations of several primary standard cells calibrated on high altitude balloons show agreement within 0.5 per cent. Prediction of the output of satellite power supplies using airplane calibrated cells shows an accuracy of better than 1 per cent.

  9. A Novel Candidate Region for Genetic Adaptation to High Altitude in Andean Populations

    PubMed Central

    Lippold, Sebastian; de Filippo, Cesare; Tang, Kun; López Herráez, David; Li, Jing; Stoneking, Mark

    2015-01-01

    Humans living at high altitude (≥2,500 meters above sea level) have acquired unique abilities to survive the associated extreme environmental conditions, including hypoxia, cold temperature, limited food availability and high levels of free radicals and oxidants. Long-term inhabitants of the most elevated regions of the world have undergone extensive physiological and/or genetic changes, particularly in the regulation of respiration and circulation, when compared to lowland populations. Genome scans have identified candidate genes involved in altitude adaption in the Tibetan Plateau and the Ethiopian highlands, in contrast to populations from the Andes, which have not been as intensively investigated. In the present study, we focused on three indigenous populations from Bolivia: two groups of Andean natives, Aymara and Quechua, and the low-altitude control group of Guarani from the Gran Chaco lowlands. Using pooled samples, we identified a number of SNPs exhibiting large allele frequency differences over 900,000 genotyped SNPs. A region in chromosome 10 (within the cytogenetic bands q22.3 and q23.1) was significantly differentiated between highland and lowland groups. We resequenced ~1.5 Mb surrounding the candidate region and identified strong signals of positive selection in the highland populations. A composite of multiple signals like test localized the signal to FAM213A and a related enhancer; the product of this gene acts as an antioxidant to lower oxidative stress and may help to maintain bone mass. The results suggest that positive selection on the enhancer might increase the expression of this antioxidant, and thereby prevent oxidative damage. In addition, the most significant signal in a relative extended haplotype homozygosity analysis was localized to the SFTPD gene, which encodes a surfactant pulmonary-associated protein involved in normal respiration and innate host defense. Our study thus identifies two novel candidate genes and associated pathways

  10. High-altitude headache: the effects of real vs sham oxygen administration.

    PubMed

    Benedetti, Fabrizio; Durando, Jennifer; Giudetti, Lucia; Pampallona, Alan; Vighetti, Sergio

    2015-11-01

    High-altitude, or hypobaric hypoxia, headache has recently emerged as an interesting model to study placebo and nocebo responses, and particularly their peripheral mechanisms. In this study, we analyze the response of this type of headache to either real or sham (placebo) oxygen (O(2)) administration at an altitude of 3500 m, where blood oxygen saturation (SO(2)) drops from the normal value of about 98% to about 85%. In a trial in which a double-blind administration of either 100% O(2) or sham O(2) was administered, we tested pre- and post-exercise headache, along with fatigue, heart rate (HR) responses, and prostaglandin E(2) (PGE(2)) salivary concentration. Although real O(2) breathing increased SO(2) along with a decrease in pre- and post-exercise headache, fatigue, HR, and PGE(2), placebo O(2) changed neither pre-/post-exercise headache nor SO(2)/HR/PGE(2), but it decreased fatigue. However, in another group of subjects, when sham O(2) was delivered after 2 previous exposures to O(2) (O(2) preconditioning), it decreased fatigue, post-exercise headache, HR, and PGE(2), yet without any increase in SO(2). Three main findings emerge from these data. First, placebo O(2) is effective in reducing post-exercise headache, along with HR and PGE(2) decrease, only after O(2) preconditioning. Second, pre-exercise (at rest) headache is not affected by placebo O(2), which emphasizes the limits of a placebo treatment at high altitude. Third, fatigue is affected by placebo O(2) even without prior O(2) conditioning, which suggests the higher placebo sensitivity of fatigue compared with headache pain at high altitude.

  11. Human adaptation to high altitude: regional and life-cycle perspectives.

    PubMed

    Moore, L G; Niermeyer, S; Zamudio, S

    1998-01-01

    Studies of the ways in which persons respond to the adaptive challenges of life at high altitude have occupied an important place in anthropology. There are three major regions of the world where high-altitude studies have recently been performed: the Himalayas of Asia, the Andes of South America, and the Rocky Mountains of North America. Of these, the Himalayan region is larger, more geographically remote, and likely to have been occupied by humans for a longer period of time and to have been subject to less admixture or constriction of its gene pool. Recent studies of the physiological responses to hypoxia across the life cycle in these groups reveal several differences in adaptive success. Compared with acclimatized newcomers, lifelong residents of the Andes and/or Himalayas have less intrauterine growth retardation, better neonatal oxygenation, and more complete neonatal cardiopulmonary transition, enlarged lung volumes, decreased alveolar-arterial oxygen diffusion gradients, and higher maximal exercise capacity. In addition, Tibetans demonstrate a more sustained increase in cerebral blood flow during exercise, lower hemoglobin concentration, and less susceptibility to chronic mountain sickness (CMS) than acclimatized newcomers. Compared to Andean or Rocky Mountain high-altitude residents, Tibetans demonstrate less intrauterine growth retardation, greater reliance on redistribution of blood flow than elevated arterial oxygen content to increase uteroplacental oxygen delivery during pregnancy, higher levels of resting ventilation and hypoxic ventilatory responsiveness, less hypoxic pulmonary vasoconstriction, lower hemoglobin concentration, and less susceptibility to CMS. Several of the distinctions demonstrated by Tibetans parallel the differences between natives and newcomers, suggesting that the degree of protection or adaptive benefit relative to newcomers is enhanced for the Tibetans. We thus conclude that Tibetans have several physiological distinctions

  12. Infrared astronomy research and high altitude observations

    NASA Technical Reports Server (NTRS)

    Jones, B.; Stein, W. A.; Willner, S. P.; Soifer, B. T.

    1984-01-01

    Highlights are presented of studies of the emission mechanisms in the 4 to 8 micron region of the spectrum using a circular variable filter wheel spectrometer with a PbSnTe photovoltaic detector. Investigations covered include the spectroscopy of planets, stellar atmospheres, highly obscured objects in molecular clouds, planetary nebulae, H2 regions, and extragalactic objects.

  13. A method for sampling microbial aerosols using high altitude balloons.

    PubMed

    Bryan, N C; Stewart, M; Granger, D; Guzik, T G; Christner, B C

    2014-12-01

    Owing to the challenges posed to microbial aerosol sampling at high altitudes, very little is known about the abundance, diversity, and extent of microbial taxa in the Earth-atmosphere system. To directly address this knowledge gap, we designed, constructed, and tested a system that passively samples aerosols during ascent through the atmosphere while tethered to a helium-filled latex sounding balloon. The sampling payload is ~ 2.7 kg and comprised of an electronics box and three sampling chambers (one serving as a procedural control). Each chamber is sealed with retractable doors that can be commanded to open and close at designated altitudes. The payload is deployed together with radio beacons that transmit GPS coordinates (latitude, longitude and altitude) in real time for tracking and recovery. A cut mechanism separates the payload string from the balloon at any desired altitude, returning all equipment safely to the ground on a parachute. When the chambers are opened, aerosol sampling is performed using the Rotorod® collection method (40 rods per chamber), with each rod passing through 0.035 m3 per km of altitude sampled. Based on quality control measurements, the collection of ~ 100 cells rod(-1) provided a 3-sigma confidence level of detection. The payload system described can be mated with any type of balloon platform and provides a tool for characterizing the vertical distribution of microorganisms in the troposphere and stratosphere. PMID:25455021

  14. The role of oxygen-increased respirator in humans ascending to high altitude

    PubMed Central

    2012-01-01

    Background Acute mountain sickness (AMS) is common for people who live in low altitude areas ascending to the high altitude. Many instruments have been developed to treat mild cases of AMS. However, long-lasting and portable anti-hypoxia equipment for individual is not yet available. Methods Oxygen-increased respirator (OIR) has been designed to reduce the risk of acute mountain sickness in acute exposure to low air pressure. It can increase the density of oxygen by increasing total atmospheric pressure in a mask. Male subjects were screened, and eighty-eight were qualified to perform the experiments. The subjects were divided into 5 groups and were involved in some of the tests at 4 different altitudes (Group 1, 2: 3700 m; Group 3,4,5: 4000 m, 4700 m, 5380 m) with and without OIR. These tests include heart rate, saturation of peripheral oxygen (SpO2), malondialdehyde (MDA), superoxide dismutase (SOD), blood lactate (BLA) and PWC (physical work capacity) -170. Results The results showed that higher SpO2, lower heart rate (except during exercise) and better recovery of heart rate were observed from all the subjects ’with OIR’ compared with ’without OIR’ (P<0.05). Moreover, compared with ’without OIR’, subjects ’with OIR’ in Group 1 had lower concentrations of MDA and BLA, and a higher concentration of SOD (P<0.05), while subjects ’with OIR’ in Group 2 showed better physical capacity (measured by the PWC-170) (P<0.05). The additional experiment conducted in a hypobaric chamber (simulating 4,000 m) showed that the partial pressure of oxygen in blood and arterial oxygen saturation were higher ’with OIR’ than ’without OIR’ (P<0.05). Conclusions We suggested that OIR may play a useful role in protecting people ascending to high altitude before acclimatization. PMID:22898206

  15. HCN ice in Titan's high-altitude southern polar cloud.

    PubMed

    de Kok, Remco J; Teanby, Nicholas A; Maltagliati, Luca; Irwin, Patrick G J; Vinatier, Sandrine

    2014-10-01

    Titan's middle atmosphere is currently experiencing a rapid change of season after northern spring arrived in 2009 (refs 1, 2). A large cloud was observed for the first time above Titan's southern pole in May 2012, at an altitude of 300 kilometres. A temperature maximum was previously observed there, and condensation was not expected for any of Titan's atmospheric gases. Here we report that this cloud is composed of micrometre-sized particles of frozen hydrogen cyanide (HCN ice). The presence of HCN particles at this altitude, together with temperature determinations from mid-infrared observations, indicate a dramatic cooling of Titan's atmosphere inside the winter polar vortex in early 2012. Such cooling is in contrast to previously measured high-altitude warming in the polar vortex, and temperatures are a hundred degrees colder than predicted by circulation models. These results show that post-equinox cooling at the winter pole of Titan is much more efficient than previously thought. PMID:25279918

  16. Nonequilibrium viscous flow over Jovian entry probes at high altitudes

    NASA Technical Reports Server (NTRS)

    Kumar, A.; Szema, K. Y.; Tiwari, S. N.

    1979-01-01

    The viscous chemical nonequilibrium flow around a Jovian entry body is investigated at high altitudes using two different methods. First method is only for the stagnation region and integrates the full Navier-Stokes equations from the body surface to the freestream. The second method uses viscous shock layer equations between the body surface and the shock. Due to low Reynolds numbers, both methods use surface slip boundary conditions and the second method also uses shock slip boundary conditions. The results of the two methods are compared at the stagnation point. It is found that the entire shock layer is under chemical nonequilibrium at higher altitudes and that the slip boundary conditions are important at these altitudes.

  17. Anti-Hypotensive Treatment and Endothelin Blockade Synergistically Antagonize Exercise Fatigue in Rats under Simulated High Altitude

    PubMed Central

    Radiloff, Daniel; Zhao, Yulin; Boico, Alina; Blueschke, Gert; Palmer, Gregory; Fontanella, Andrew; Dewhirst, Mark; Piantadosi, Claude A.; Noveck, Robert; Irwin, David; Hamilton, Karyn; Klitzman, Bruce; Schroeder, Thies

    2014-01-01

    Rapid ascent to high altitude causes illness and fatigue, and there is a demand for effective acute treatments to alleviate such effects. We hypothesized that increased oxygen delivery to the tissue using a combination of a hypertensive agent and an endothelin receptor A antagonist drugs would limit exercise-induced fatigue at simulated high altitude. Our data showed that the combination of 0.1 mg/kg ambrisentan with either 20 mg/kg ephedrine or 10 mg/kg methylphenidate significantly improved exercise duration in rats at simulated altitude of 4,267 m, whereas the individual compounds did not. In normoxic, anesthetized rats, ephedrine alone and in combination with ambrisentan increased heart rate, peripheral blood flow, carotid and pulmonary arterial pressures, breathing rate, and vastus lateralis muscle oxygenation, but under inspired hypoxia, only the combination treatment significantly enhanced muscle oxygenation. Our results suggest that sympathomimetic agents combined with endothelin-A receptor blockers offset altitude-induced fatigue in rats by synergistically increasing the delivery rate of oxygen to hypoxic muscle by concomitantly augmenting perfusion pressure and improving capillary conductance in the skeletal muscle. Our findings might therefore serve as a basis to develop an effective treatment to prevent high-altitude illness and fatigue in humans. PMID:24960187

  18. Use of the Gamow Bag by EMT-basic park rangers for treatment of high-altitude pulmonary edema and high-altitude cerebral edema.

    PubMed

    Freeman, Kimberly; Shalit, Marc; Stroh, Geoffrey

    2004-01-01

    As part of an emergency medical system protocol, national park service rangers certified at the level of an emergency medical technician-basic (EMT-B) are taught to recognize and treat high-altitude pulmonary edema and high-altitude cerebral edema. In Sequoia and Kings Canyon National Parks, this is done with the assistance of physician on-line medical control as a backup. High-altitude pulmonary edema and high-altitude cerebral edema are both potentially fatal altitude illnesses that can be particularly problematic in the backcountry, where evacuation may be delayed. We report a case of high-altitude pulmonary edema and high-altitude cerebral edema occurring at moderate altitude that was successfully treated by park rangers with the Gamow Bag.

  19. High altitude, prolonged exercise, and the athlete biological passport.

    PubMed

    Schumacher, Yorck O; Garvican, Laura A; Christian, Ryan; Lobigs, Louisa M; Qi, Jiliang; Fan, Rongyun; He, Yingying; Wang, Hailing; Gore, Christopher J; Ma, Fuhai

    2015-01-01

    The Athlete Biological Passport (ABP) detects blood doping in athletes through longitudinal monitoring of erythropoietic markers. Mathematical algorithms are used to define individual reference ranges for these markers for each athlete. It is unclear if altitude and exercise can affect the variables included in these calculations in a way that the changes might be mistaken for blood manipulation. The aim of this study was to investigate the influence of the simultaneous strenuous exercise and low to high altitude exposure on the calculation algorithms of the ABP. 14 sea level (SL) and 11 altitude native (ALT) highly trained athletes participated in a 14-day cycling stage race taking place at an average altitude of 2496 m above sea level (min. 1014 m, max. 4120 m), race distances ranged between 96 and 227 km per day. ABP blood measures were taken on days -1,3,6,10,14 (SL) and -1,9,15 (ALT) of the race. Four results from three samples of two different SL athletes exceeded the individual limits at the 99% specificity threshold and one value at 99.9%. In ALT, three results from three samples of three different athletes were beyond the individual limits at 99%, one at 99.9%. The variations could be explained by the expected physiological reaction to exercise and altitude. In summary, the abnormalities observed in the haematological ABP´s of well-trained athletes during extensive exercise at altitude are limited and in line with expected physiological changes.

  20. 40 CFR 600.310-86 - Labeling of high altitude vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Labeling of high altitude vehicles... Regulations for 1977 and Later Model Year Automobiles-Labeling § 600.310-86 Labeling of high altitude vehicles... altitude vehicles according to § 600.306. (b) A high altitude vehicle may be labeled with a general...

  1. Chicxulub High-Altitude Ballistic Ejecta from Central Belize

    NASA Technical Reports Server (NTRS)

    Pope, K. O.; Ocampo, A. C.

    2000-01-01

    Chicxulub ejecta are found in central Belize, 475 km southeast of the impact crater center. These deposits are ballistic ejecta launched along high-altitude trajectories above the atmosphere and deposited as a discontinuous sheet on the terminal Cretaceous land surface.

  2. Physiological effects of intermittent hypoxia.

    PubMed

    Powell, F L; Garcia, N

    2000-01-01

    Intermittent hypoxia (IH), or periodic exposure to hypoxia interrupted by return to normoxia or less hypoxic conditions, occurs in many circumstances. In high altitude mountaineering, IH is used to optimize acclimatization although laboratory studies have not generally revealed physiologically significant benefits. IH enhances athletic performance at sea level if blood oxygen capacity increases and the usual level of training is not decreased significantly. IH for high altitude workers who commute from low altitude homes is of considerable practical interest and the ideal commuting schedule for physical and mental performance is being studied. The effect of oxygen enrichment at altitude (i.e., intermittent normoxia on a background of chronic hypoxia) on human performance is under study also. Physiological mechanisms of IH, and specifically the differences between effects of IH and acute or chronic continuous hypoxia remains to be determined. Biomedical researchers are defining the molecular and cellular mechanisms for effects of hypoxia on the body in health and disease. A comparative approach may provide additional insight about the biological significance of these effects.

  3. Snowpack and precipitation chemistry at high altitudes

    NASA Astrophysics Data System (ADS)

    Hidy, George M.

    As an observational scientist, James P. Lodge Jr. contributed to the knowledge of atmospheric chemistry significantly and in many ways. As far back as the 1960s, his achievements included organization and oversight of a national survey of precipitation chemistry. This paper recognizes his broad interest in precipitation, focusing on recent studies of snow chemistry in the high-elevation regimes. A brief overview of snow chemistry in the American Rocky Mountains is provided in the context of other snow chemistry studies in the United States, Europe, the Himalayas, and the polar ice-sheets. A comparison of major ion concentrations in snow and neighboring NADP wet deposition sites in the Rocky Mountains follows. These data are then put in perspective of the major ion concentrations observed in snow at different global locations. This comparison touches on the similarities and differences in ion concentrations in the mid-latitude sites and the Polar Regions. A case study is reviewed to identify specific sources of sulfur and nitrogen oxides affecting snow chemistry in the American Rockies. The survey closes with a brief discussion of potentially important recent observations of snowpack chemistry interactions with the troposphere, the hydrosphere and the lithosphere.

  4. Going High with Heart Disease: The Effect of High Altitude Exposure in Older Individuals and Patients with Coronary Artery Disease.

    PubMed

    Levine, Benjamin D

    2015-06-01

    Levine, Benjamin D. Going high with heart disease: The effect of high altitude exposure in older individuals and patients with coronary artery disease. High Alt Med Biol 16:89-96, 2015.--Ischemic heart disease is the largest cause of death in older men and women in the western world (Lozano et al., 2012 ; Roth et al., 2015). Atherosclerosis progresses with age, and thus age is the dominant risk factor for coronary heart disease in any algorithm used to assess risk for cardiovascular events. Subclinical atherosclerosis also increases with age, providing the substrate for precipitation of acute coronary syndromes. Thus the risk of high altitude exposure in older individuals is linked closely with both subclinical and manifest coronary heart disease (CHD). There are several considerations associated with taking patients with CHD to high altitude: a) The reduced oxygen availability may cause or exacerbate symptoms; b) The hypoxia and other associated environmental conditions (exercise, dehydration, change in diet, thermal stress, emotional stress from personal danger or conflict) may precipitate acute coronary events; c) If an event occurs and the patient is far from advanced medical care, then the outcome of an acute coronary event may be poor; and d) Sudden death may occur. Physicians caring for older patients who want to sojourn to high altitude should keep in mind the following four key points: 1). Altitude may exacerbate ischemic heart disease because of both reduced O2 delivery and paradoxical vasoconstriction; 2). Adverse events, including acute coronary syndromes and sudden cardiac death, are most common in older unfit men, within the first few days of altitude exposure; 3). Ensuring optimal fitness, allowing for sufficient acclimatization (at least 5 days), and optimizing medical therapy (especially statins and aspirin) are prudent recommendations that may reduce the risk of adverse events; 4). A graded exercise test at sea level is probably sufficient for

  5. Respiratory gas exchange of high altitude adapted chick embryos

    NASA Technical Reports Server (NTRS)

    Wangensteen, O. D.; Rahn, H.; Burton, R. R.; Smith, A. H.

    1974-01-01

    Study of gas exchange by embryos from chickens acclimatized to an altitude of 3800 m. The oxygen partial pressure and carbon dioxide partial pressure differences across the egg shell were measured and found to be less than the values previously reported for sea-level eggs by about a factor of two. Further measurements of embryonic oxygen consumption and shell conductivity to oxygen indicated that, compared to eggs at sea level, oxygen consumption was reduced by a factor of 0.58 while conductivity to oxygen was increased only by a factor of 1.07 in the high-altitude eggs. These independent measurements predict the change in oxygen partial pressure across the egg shell of the high-altitude eggs to be only 0.54 times that of sea-level eggs; the directly measured factor was 0.53. The authors conclude that at high altitude, a major adaptation of the chick embryo is a reduced metabolism which decreases the change in oxygen partial pressure across the egg shell since its gas conductivity remains essentially unchanged.

  6. Theodor Benzinger, German pioneer in high altitude physiology research and altitude protection.

    PubMed

    Harsch, Viktor

    2007-09-01

    Theodore Benzinger was a pilot-physician who performed pioneering research-often involving self-experimentation-in areas related to flight at high altitude during World War II. Of greatest historical interest to those of us in aerospace medicine is his work on the effects of rapid decompression and related oxygen equipment. Benzinger was born in Stuttgart, Germany, on 28th August 1905. He studied medicine and natural sciences at the universities of Tuebingen, Munich, and Berlin. From 1934 to 1944, Benzinger headed the aeromedical laboratory "EMed" in Rechlin, where he was instrumental in conducting studies related to stratospheric flight, including self-experimentation with rapid decompression up to 19,000 m (62,320 ft). His Rechlin experiments made an important contribution to understanding the physiology and life-support requirements for high-altitude aviation and later work under space-equivalent conditions. Following World War II, Benzinger joined the staff of the U.S. Army Air Force Aeromedical Center in Heidelberg. In 1947 he was recruited by "Operation Paperclip" to work at the U.S. Naval Medical Research Institute (NMRI) in Bethesda, MD, where he worked on various aspects of human physiology. He died as a U.S. citizen in Bethesda, MD, on 26th October 1999.

  7. Martian high-altitude photoelectrons independent of solar zenith angle

    NASA Astrophysics Data System (ADS)

    Xu, Shaosui; Liemohn, Michael; Bougher, Stephen; Mitchell, David

    2016-04-01

    Many aspects of the Martian upper atmosphere are known to vary with solar zenith angle (SZA). One would assume that dayside photoelectron fluxes are also SZA dependent, especially when transport along a semivertical magnetic field line is significant. However, our investigation presented here of the observed Martian high-altitude (˜400 km) photoelectron fluxes by the magnetometer/electron reflectometer (MAG/ER) instruments on board Mars Global Surveyor (MGS) shows that the photoelectron fluxes are better correlated with just the solar irradiance, without SZA factored in, and also that the median photoelectron fluxes are independent of SZA, especially for high energies (above 100 eV). For lower energies (below 70 eV), the observed fluxes tend to vary to some degree with SZA. Such counterintuitive results are due to the existence of a photoelectron exobase, only above which the photoelectrons are able to transport and escape to high altitudes. Two methods are used here to determine the altitude range of this exobase, which varies between 145 km and 165 km depending on the atmosphere and SZA. Through our SuperThermal Electron Transport (STET) model, we found that the integral of the production rate above the photoelectron exobase, and therefore the high-altitude photoelectron fluxes, is rather independent of SZA. Such an independent relationship concerns energy redistribution in the Martian upper atmosphere, using photoelectrons to map magnetic topology and connectivity, as well as ion escape. This finding can also be carefully adapted to other solar bodies with semivertical magnetic fields at ionospheric altitudes, such as Earth, Jupiter, and Saturn.

  8. Project ARES 2: High-altitude battery-powered aircraft

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A high-altitude, battery-powered, propeller-driven aircraft was designed and is being built by undergraduate students at California State University, Northridge. The aircraft will fly at an altitude of 104,000 ft at Mach 0.2 (190 ft/sec) and will be instrumented to record flight performance data, including low Reynolds number propeller and airfoil information. This project will demonstrate the feasibility of electric-powered flight in a low-density, low-temperature Earth environment that models the atmosphere of Mars. Data collected will be used to design a Mars aircraft to investigate the surface of Mars prior to manned missions. The instrumented payload and the mission profile for the high-altitude Earth flight were determined. Detailed aerodynamic and structural analyses were performed. Control, tracking, and data recording subsystems were developed. Materials were obtained and fabrication begun. The aircraft has a 32-ft wing span, a wing area of 105 sq ft, is 17.5 ft long, has a 12-in payload bay, and weighs 42 lb. It is composed primarily of lightweight materials, including Mylar, and composite materials, including graphite/epoxy and aramid core honeycomb sandwich. Low-altitude flight testing to check guidance and control systems and to calibrate data-gathering instruments will take place this summer, followed shortly by the 104,000-ft flight.

  9. Anthropometric and body composition changes during expeditions at high altitude.

    PubMed

    Zaccagni, Luciana; Barbieri, Davide; Cogo, Annalisa; Gualdi-Russo, Emanuela

    2014-06-01

    The purpose of this study is to investigate separately in the two sexes the physical adaptations associated to exposure to high altitude in a sample of 18 nonacclimatized Caucasian subjects (10 males and 8 females, 22-59 years) who participated to scientific expeditions to Himalaya up to the Pyramid Laboratory (5050 m, Nepal) or Everest North Base Camp (5300 m, Tibet). Anthropometric traits (body height and weight, eight girths and six skinfolds) were collected according to standard procedures, before departure at sea level, during ascent (at altitude > 4000 m above sea level), and after return to low altitude. Body composition was assessed by means of the skinfold method. Both sexes lost on average 4.0% of initial body mass, corresponding to 7.6% of fat mass and 3.5% of fat free mass in males, and to 5.0% of fat mass and 3.6% of fat free mass in females. Average fat mass loss was greater in males than in females. Initial fat mass percentage was positively correlated to fat mass loss and negatively to FFM loss in males only, thus at HA leanest subjects lost more FFM and less FM than the fattest ones. Adaptations were faster in males than in females. In conclusion, the present research describes significant adaptations to high altitude, in terms of body weight reduction, regardless of the amount of performed physical activity. PMID:24665979

  10. Increased Lung Volume in Infants and Toddlers at High Compared to Low Altitude

    PubMed Central

    Llapur, Conrado J.; Martínez, Myriam R.; Caram, María Marta; Bonilla, Federico; Cabana, Celia; Yu, Zhansheng; Tepper, Robert S.

    2015-01-01

    Summary Children and adults residing at high altitude (HA) compared to low altitude (LA) have larger lung volumes; however, it is unknown whether this response to chronic hypoxia begins early in life. Our objective was to determine whether infants and toddlers at HA have larger lung volumes compared to infants and toddlers at LA. Oxygen saturation (SaO2), functional residual capacity (FRC), as well as serum levels of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) were measured in infants and toddlers from HA (N = 50; 3,440 m) and LA (N = 35; 440 m). There were no significant differences in somatic size for HA and LA subjects; however, HA subjects had significantly lower SaO2 (88.5% vs. 96.7%; P < 0.0001). Subjects at HA had significantly greater FRC compared to subjects at LA (group mean: 209 and 157 ml; P < 0.0001), adjusting for body length. Male infants at HA had a significantly greater FRC compared to males at LA (57 ml; P-value < 0.001); however, the increase in FRC for females at HA compared to LA was not significant (20 ml; P-value = 0.101). VEGF and EPO were significantly higher for subjects at HA compared to LA with no gender differences. In summary, infants and toddlers at HA have lower oxygen saturations, higher serum levels of VEGF and EPO, and higher FRC compared to subjects at LA; however, chronic hypoxia appears to generate a more robust response in lung growth in male compared to female infants early in life. PMID:23401418

  11. An oxygen enrichment device for lowlanders ascending to high altitude

    PubMed Central

    2013-01-01

    Background When ascending to the high altitude, people living in low altitude areas will suffer from acute mountain sickness. The aim of this study is to test the hypothesis that whether an oxygen concentration membrane can be made and used to construct a new portable oxygen enrichment device for individuals in acute exposure to the high altitude. Methods The membrane was fabricated using vinylsiloxane rubber, polyphenylene oxide hydrogen silicone polymers, chloroplatinic acid and isopropyl alcohol. The membrane was assembled in a frame and the performance was tested in terms of concentration of oxygen, flow rate of oxygen enriched air, pressure ratio across the membrane and ambient temperature. Furthermore, the oxygen concentration device was constructed using the membrane, a DC fan, vacuum pump and gas buffer. A nonrandomized preliminary field test was conducted, in which eight healthy male subjects were flown to Tibet (Lhasa, 3,700 m). First, subjects wore the oxygen enrichment device and performed an incremental exercise on cycle ergometer. The test included heart rate (HR), saturation of peripheral oxygen (SpO2) and physical work capacity (PWC). Then, after a rest period of 4 hours, the experimental protocol was repeated without oxygen enrichment device. Results The testing showed that the membrane could increase the oxygen concentration by up to 30%. Simulation test indicated that although the performance of the oxygen enrichment device decreased with altitudes, the oxygen concentration could still maintain 28% with flow rate of enriched air 110 cm3/s at 5000 m. The field test showed that higher SpO2, lower HR, and better PWC (measured by the PWC-170) were observed from all the subjects using oxygen enrichment device compared with non-using (P < 0.01). Conclusions We concluded that the new portable oxygen enrichment device would be effective in improving exercise performance when ascending to the high altitude. PMID:24103365

  12. Inhibition of inducible nitric oxide synthase expression and nitric oxide production in plateau pika (Ochotona curzoniae) at high altitude on Qinghai-Tibet Plateau.

    PubMed

    Xie, Ling; Zhang, Xuze; Qi, Delin; Guo, Xinyi; Pang, Bo; Du, Yurong; Zou, Xiaoyan; Guo, Songchang; Zhao, Xinquan

    2014-04-30

    Nitric oxide (NO), a potent vasodilator, plays an important role in preventing hypoxia induced pulmonary hypertension. Endogenous NO is synthesized by nitric oxide synthases (NOSs) from l-arginine. In mammals, three different NOSs have been identified, including neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS). Plateau pika (Ochotona curzoniae) is a typical hypoxia tolerant mammal that lives at 3000-5000 m above sea level on the Qinghai-Tibet Plateau. The aim of this study was to investigate whether NOS expression and NO production are regulated by chronic hypoxia in plateau pika. Quantitative real-time PCR and western blot analyses were conducted to quantify relative abundances of iNOS and eNOS transcripts and proteins in the lung tissues of plateau pikas at different altitudes (4550, 3950 and 3200 m). Plasma NO metabolites, nitrite/nitrate (NO(x)⁻) levels were also examined by Ion chromatography to determine the correlation between NO production and altitude level. The results revealed that iNOS transcript levels were significantly lower in animals at high altitudes (decreased by 53% and 57% at altitude of 3950 and 4550 m compared with that at 3200 m). Similar trends in iNOS protein abundances were observed (26% and 41% at 3950 and 4550 m comparing with at 3200 m). There were no significant differences in eNOS mRNA and protein levels in the pika lungs among different altitudes. The plasma NO(x)⁻ levels of the plateau pikas at high altitudes significantly decreased (1.65±0.19 μg/mL at 3200 m to 0.44±0.03 μg/mL at 3950 m and 0.24±0.01 μg/mL at 4550 m). This is the first evidence describing the effects of chronic hypoxia on NOS expression and NO levels in the plateau pika in high altitude adaptation. We conclude that iNOS expression and NO production are suppressed at high altitudes, and the lower NO concentration at high altitudes may serve crucial roles for helping the plateau pika to survive at hypoxic environment.

  13. Lockheed ER-2 #806 high altitude research aircraft during landing

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 806, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  14. Lockheed ER-2 #809 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1999-01-01

    ER-2 tail number 809, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  15. High altitude solar power platform. [aircraft design analysis

    NASA Technical Reports Server (NTRS)

    Bailey, M. D.; Bower, M. V.

    1992-01-01

    Solar power is a preeminent alternative to conventional aircraft propulsion. With the continued advances in solar cells, fuel cells, and composite materials technology, the solar powered airplane is no longer a simple curiosity constrained to flights of several feet in altitude or minutes of duration. A high altitude solar powered platform (HASPP) has several potential missions, including communications and agriculture. In remote areas, a HASPP could be used as a communication link. In large farming areas, a HASPP could perform remote sensing of crops. The impact of HASPP in continuous flight for one year on agricultural monitoring mission is presented. This mission provides farmers with near real-time data twice daily from an altitude which allows excellant resolution on water conditions, crop diseases, and insect infestation. Accurate, timely data will enable farmers to increase their yield and efficiency. A design for HASPP for the foregoing mission is presented. In the design power derived from solar cells covering the wings is used for propulsion, avionics, and sensors. Excess power produced midday will be stored in fuel cells for use at night to maintain altitude and course.

  16. Lockheed ER-2 #809 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 809, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  17. Functional Genomic Insights into Regulatory Mechanisms of High-Altitude Adaptation.

    PubMed

    Storz, Jay F; Cheviron, Zachary A

    2016-01-01

    Recent studies of indigenous human populations at high altitude have provided proof-of-principle that genome scans of DNA polymorphism can be used to identify candidate loci for hypoxia adaptation. When integrated with experimental analyses of physiological phenotypes, genome-wide surveys of DNA polymorphism and tissue-specific transcriptional profiles can provide insights into actual mechanisms of adaptation. It has been suggested that adaptive phenotypic evolution is largely mediated by cis-regulatory changes in genes that are located at integrative control points in regulatory networks. This hypothesis can be tested by conducting transcriptomic analyses of hypoxic signaling pathways in conjunction with experimental measures of vascular oxygen supply and metabolic pathway flux. Such studies may reveal whether the architecture of gene regulatory networks can be used to predict which loci (and which types of loci) are likely to be "hot spots" for adaptive physiological evolution. Functional genomic studies of deer mice (Peromyscus maniculatus) demonstrate how the integrated analysis of variation in tissue-specific transcriptomes, whole-animal physiological performance, and various subordinate traits can yield insights into the mechanistic underpinnings of high-altitude adaptation. PMID:27343092

  18. Genomic Analyses Reveal Potential Independent Adaptation to High Altitude in Tibetan Chickens.

    PubMed

    Wang, Ming-Shan; Li, Yan; Peng, Min-Sheng; Zhong, Li; Wang, Zong-Ji; Li, Qi-Ye; Tu, Xiao-Long; Dong, Yang; Zhu, Chun-Ling; Wang, Lu; Yang, Min-Min; Wu, Shi-Fang; Miao, Yong-Wang; Liu, Jian-Ping; Irwin, David M; Wang, Wen; Wu, Dong-Dong; Zhang, Ya-Ping

    2015-07-01

    Much like other indigenous domesticated animals, Tibetan chickens living at high altitudes (2,200-4,100 m) show specific physiological adaptations to the extreme environmental conditions of the Tibetan Plateau, but the genetic bases of these adaptations are not well characterized. Here, we assembled a de novo genome of a Tibetan chicken and resequenced whole genomes of 32 additional chickens, including Tibetan chickens, village chickens, game fowl, and Red Junglefowl, and found that the Tibetan chickens could broadly be placed into two groups. Further analyses revealed that several candidate genes in the calcium-signaling pathway are possibly involved in adaptation to the hypoxia experienced by these chickens, as these genes appear to have experienced directional selection in the two Tibetan chicken populations, suggesting a potential genetic mechanism underlying high altitude adaptation in Tibetan chickens. The candidate selected genes identified in this study, and their variants, may be useful targets for clarifying our understanding of the domestication of chickens in Tibet, and might be useful in current breeding efforts to develop improved breeds for the highlands. PMID:25788450

  19. Syndrome of acute anxiety among marines after recent arrival at high altitude.

    PubMed

    Sracic, Michael K; Thomas, Darren; Pate, Allen; Norris, Jacob; Norman, Marc; Gertsch, Jeffrey H

    2014-05-01

    Management of mental health is critical for maintenance of readiness in austere military environments. Emerging evidence implicates hypoxia as an environmental trigger of anxiety spectrum symptomatology. One thousand thirty-six unacclimatized infantry Marines ascended from sea level to the Marine Corps Mountain Warfare Training Center (2,061-3,383 m) for a 30-day exercise. Within the first 6 days of training, 7 servicemen presented with severe, acute anxiety/panic with typical accompanying signs of sympathetic activation and no classic symptoms of acute mountain sickness (including headache). Four had a history of well-controlled psychiatric diagnoses. Invariably, cardiopulmonary and neurological evaluations were unrevealing, and acute cardiopulmonary events were excluded within limits of expeditionary diagnostic capabilities. All patients responded clinically to oxygen, rest, and benzodiazepines, returning to baseline function the same day. The unexpected onset of 7 cases of acute anxiety symptomatology coincident with recent arrival at moderate-to-high altitudes represents a highly unusual incidence and temporal distribution, suggestive of hypobaric hypoxemia as the proximal cause. We propose acute hypoxic physiological anxiety (AHPA) as a unique member of the spectrum of altitude-associated neurological disorders. Recognition of AHPA is particularly relevant in a military population; warfighters with anxiety spectrum diagnoses may have a recognizable and possibly preventable vulnerability. PMID:24806502

  20. The Molecular Basis of High-Altitude Adaptation in Deer Mice

    PubMed Central

    Storz, Jay F; Sabatino, Stephen J; Hoffmann, Federico G; Gering, Eben J; Moriyama, Hideaki; Ferrand, Nuno; Monteiro, Bruno; Nachman, Michael W

    2007-01-01

    Elucidating genetic mechanisms of adaptation is a goal of central importance in evolutionary biology, yet few empirical studies have succeeded in documenting causal links between molecular variation and organismal fitness in natural populations. Here we report a population genetic analysis of a two-locus α-globin polymorphism that underlies physiological adaptation to high-altitude hypoxia in natural populations of deer mice, Peromyscus maniculatus. This system provides a rare opportunity to examine the molecular underpinnings of fitness-related variation in protein function that can be related to a well-defined selection pressure. We surveyed DNA sequence variation in the duplicated α-globin genes of P. maniculatus from high- and low-altitude localities (i) to identify the specific mutations that may be responsible for the divergent fine-tuning of hemoglobin function and (ii) to test whether the genes exhibit the expected signature of diversifying selection between populations that inhabit different elevational zones. Results demonstrate that functionally distinct protein alleles are maintained as a long-term balanced polymorphism and that adaptive modifications of hemoglobin function are produced by the independent or joint effects of five amino acid mutations that modulate oxygen-binding affinity. PMID:17397259

  1. Syndrome of acute anxiety among marines after recent arrival at high altitude.

    PubMed

    Sracic, Michael K; Thomas, Darren; Pate, Allen; Norris, Jacob; Norman, Marc; Gertsch, Jeffrey H

    2014-05-01

    Management of mental health is critical for maintenance of readiness in austere military environments. Emerging evidence implicates hypoxia as an environmental trigger of anxiety spectrum symptomatology. One thousand thirty-six unacclimatized infantry Marines ascended from sea level to the Marine Corps Mountain Warfare Training Center (2,061-3,383 m) for a 30-day exercise. Within the first 6 days of training, 7 servicemen presented with severe, acute anxiety/panic with typical accompanying signs of sympathetic activation and no classic symptoms of acute mountain sickness (including headache). Four had a history of well-controlled psychiatric diagnoses. Invariably, cardiopulmonary and neurological evaluations were unrevealing, and acute cardiopulmonary events were excluded within limits of expeditionary diagnostic capabilities. All patients responded clinically to oxygen, rest, and benzodiazepines, returning to baseline function the same day. The unexpected onset of 7 cases of acute anxiety symptomatology coincident with recent arrival at moderate-to-high altitudes represents a highly unusual incidence and temporal distribution, suggestive of hypobaric hypoxemia as the proximal cause. We propose acute hypoxic physiological anxiety (AHPA) as a unique member of the spectrum of altitude-associated neurological disorders. Recognition of AHPA is particularly relevant in a military population; warfighters with anxiety spectrum diagnoses may have a recognizable and possibly preventable vulnerability.

  2. Genomic Analyses Reveal Potential Independent Adaptation to High Altitude in Tibetan Chickens.

    PubMed

    Wang, Ming-Shan; Li, Yan; Peng, Min-Sheng; Zhong, Li; Wang, Zong-Ji; Li, Qi-Ye; Tu, Xiao-Long; Dong, Yang; Zhu, Chun-Ling; Wang, Lu; Yang, Min-Min; Wu, Shi-Fang; Miao, Yong-Wang; Liu, Jian-Ping; Irwin, David M; Wang, Wen; Wu, Dong-Dong; Zhang, Ya-Ping

    2015-07-01

    Much like other indigenous domesticated animals, Tibetan chickens living at high altitudes (2,200-4,100 m) show specific physiological adaptations to the extreme environmental conditions of the Tibetan Plateau, but the genetic bases of these adaptations are not well characterized. Here, we assembled a de novo genome of a Tibetan chicken and resequenced whole genomes of 32 additional chickens, including Tibetan chickens, village chickens, game fowl, and Red Junglefowl, and found that the Tibetan chickens could broadly be placed into two groups. Further analyses revealed that several candidate genes in the calcium-signaling pathway are possibly involved in adaptation to the hypoxia experienced by these chickens, as these genes appear to have experienced directional selection in the two Tibetan chicken populations, suggesting a potential genetic mechanism underlying high altitude adaptation in Tibetan chickens. The candidate selected genes identified in this study, and their variants, may be useful targets for clarifying our understanding of the domestication of chickens in Tibet, and might be useful in current breeding efforts to develop improved breeds for the highlands.

  3. High Resolution ECG for Evaluation of QT Interval Variability during Exposure to Acute Hypoxia

    NASA Technical Reports Server (NTRS)

    Zupet, P.; Finderle, Z.; Schlegel, Todd T.; Starc, V.

    2010-01-01

    Ventricular repolarization instability as quantified by the index of QT interval variability (QTVI) is one of the best predictors for risk of malignant ventricular arrhythmias and sudden cardiac death. Because it is difficult to appropriately monitor early signs of organ dysfunction at high altitude, we investigated whether high resolution advanced ECG (HR-ECG) analysis might be helpful as a non-invasive and easy-to-use tool for evaluating the risk of cardiac arrhythmias during exposure to acute hypoxia. 19 non-acclimatized healthy trained alpinists (age 37, 8 plus or minus 4,7 years) participated in the study. Five-minute high-resolution 12-lead electrocardiograms (ECGs) were recorded (Cardiosoft) in each subject at rest in the supine position breathing room air and then after breathing 12.5% oxygen for 30 min. For beat-to-beat RR and QT variability, the program of Starc was utilized to derive standard time domain measures such as root mean square of the successive interval difference (rMSSD) of RRV and QTV, the corrected QT interval (QTc) and the QTVI in lead II. Changes were evaluated with paired-samples t-test with p-values less than 0.05 considered statistically significant. As expected, the RR interval and its variability both decreased with increasing altitude, with p = 0.000 and p = 0.005, respectively. Significant increases were found in both the rMSSDQT and the QTVI in lead II, with p = 0.002 and p = 0.003, respectively. There was no change in QTc interval length (p = non significant). QT variability parameters may be useful for evaluating changes in ventricular repolarization caused by hypoxia. These changes might be driven by increases in sympathetic nervous system activity at ventricular level.

  4. High-Altitude Cassini Radar Imaging of Titan

    NASA Astrophysics Data System (ADS)

    West, R. D.; Stiles, B.; Anderson, Y.; Boehmer, R.; Callahan, P.; Gim, Y.; Hamilton, G.; Hensley, S.; Janssen, M.; Johnson, W. T.; Kelleher, K.; Lorenz, R.; Ostro, S.; Paganelli, F.; Shaffer, S.; Wye, L.; Zebker, H.

    2006-12-01

    The Cassini spacecraft is now about halfway through its primary Tour of the Saturn system. By the time of this meeting, the radar instrument will have collected seven synthetic aperture strips during close flyby's, with 13 more to come. These images have resolutions as fine as 300 m. We present here data acquired using another imaging mode, very high altitude synthetic aperture radar (SAR) imaging, which extends imaging radar coverage and increases coincidental coverage with other Cassini imaging instruments such as VIMS and ISS. We also discuss calibration of SAR images and other radar data from additional engineering observations. Here we examine the performance trade-offs, special processing issues, and science potential of the high- altitude image observations, and the latest results from the calibration data. The high-altitude data collections are distinct from the normal Titan radar images because the range is much larger (around 20,000 km vs 950 km to 5000 km for normal SAR passes). To increase the signal to noise ratio in these circumstances, the radar operates in the lowest bandwidth scatterometer mode while spacecraft pointing control is used to slowly pan the central beam across a small swath. These high altitude images incorporate 150-200 independent looks in order to let us discriminate features that may lie below the noise floor. So far, three high-altitude images have been acquired, during Titan flyby's T12, T13, and T15. In T12 imaging was attempted from 37000 km with an effective resolution around 5 km. In T13 the Huygens Probe landing site was imaged from 11000 km with effective resolution of 1 2 km. In T15 the Tsegehi area was imaged from 20000 km with effective resolution of 2 -3 km. Additional high altitude image segments are also planned during the T19 and T20 Titan flyby's. The calibration observations are conducted independently or coupled with a distant icy satellite observation. They consist of receive-only data in all four bandwidths

  5. High-Field MRI Reveals a Drastic Increase of Hypoxia-Induced Microhemorrhages upon Tissue Reoxygenation in the Mouse Brain with Strong Predominance in the Olfactory Bulb

    PubMed Central

    Helluy, Xavier; Milford, David; Heiland, Sabine; Bendszus, Martin

    2016-01-01

    Human pathophysiology of high altitude hypoxic brain injury is not well understood and research on the underlying mechanisms is hampered by the lack of well-characterized animal models. In this study, we explored the evolution of brain injury by magnetic resonance imaging (MRI) and histological methods in mice exposed to normobaric hypoxia at 8% oxygen for 48 hours followed by rapid reoxygenation and incubation for further 24 h under normoxic conditions. T2*-, diffusion-weighted and T2-relaxometry MRI was performed before exposure, immediately after 48 hours of hypoxia and 24 hours after reoxygenation. Cerebral microhemorrhages, previously described in humans suffering from severe high altitude cerebral edema, were also detected in mice upon hypoxia-reoxygenation with a strong region-specific clustering in the olfactory bulb, and to a lesser extent, in the basal ganglia and cerebral white matter. The number of microhemorrhages determined immediately after hypoxia was low, but strongly increased 24 hours upon onset of reoxygenation. Histologically verified microhemorrhages were exclusively located around cerebral microvessels with disrupted interendothelial tight junction protein ZO-1. In contrast, quantitative T2 and apparent-diffusion-coefficient values immediately after hypoxia and after 24 hours of reoxygenation did not show any region-specific alteration, consistent with subtle multifocal but not with regional or global brain edema. PMID:26863147

  6. High-Field MRI Reveals a Drastic Increase of Hypoxia-Induced Microhemorrhages upon Tissue Reoxygenation in the Mouse Brain with Strong Predominance in the Olfactory Bulb.

    PubMed

    Hoffmann, Angelika; Kunze, Reiner; Helluy, Xavier; Milford, David; Heiland, Sabine; Bendszus, Martin; Pham, Mirko; Marti, Hugo H

    2016-01-01

    Human pathophysiology of high altitude hypoxic brain injury is not well understood and research on the underlying mechanisms is hampered by the lack of well-characterized animal models. In this study, we explored the evolution of brain injury by magnetic resonance imaging (MRI) and histological methods in mice exposed to normobaric hypoxia at 8% oxygen for 48 hours followed by rapid reoxygenation and incubation for further 24 h under normoxic conditions. T2*-, diffusion-weighted and T2-relaxometry MRI was performed before exposure, immediately after 48 hours of hypoxia and 24 hours after reoxygenation. Cerebral microhemorrhages, previously described in humans suffering from severe high altitude cerebral edema, were also detected in mice upon hypoxia-reoxygenation with a strong region-specific clustering in the olfactory bulb, and to a lesser extent, in the basal ganglia and cerebral white matter. The number of microhemorrhages determined immediately after hypoxia was low, but strongly increased 24 hours upon onset of reoxygenation. Histologically verified microhemorrhages were exclusively located around cerebral microvessels with disrupted interendothelial tight junction protein ZO-1. In contrast, quantitative T2 and apparent-diffusion-coefficient values immediately after hypoxia and after 24 hours of reoxygenation did not show any region-specific alteration, consistent with subtle multifocal but not with regional or global brain edema. PMID:26863147

  7. High altitude pulmonary edema among “Amarnath Yatris”

    PubMed Central

    Koul, Parvaiz A.; Khan, Umar Hafiz; Hussain, Tajamul; Koul, Ajaz Nabi; Malik, Sajjad; Shah, Sanaullah; Bazaz, Sajjad Rajab; Rashid, Wasim; Jan, Rafi Ahmad

    2013-01-01

    Background: Annual pilgrimage (Yatra) to the cave shrine of Shri Amarnath Ji’ is a holy ritual among the Hindu devotees of Lord Shiva. Located in the Himalayan Mountain Range (altitude 13,000 ft) in south Kashmir, the shrine is visited by thousands of devotees and altitude sickness is reportedly common. Materials and Methods: More than 600,000 pilgrims visited the cave shrine in 2011 and 2012 with 239 recorded deaths. Thirty one patients with suspected altitude sickness were referred from medical centers en-route the cave to Sher-i-Kashmir Institute of Medical Sciences, a tertiary-care center in capital Srinagar (5,000 ft). The clinical features and the response to treatment were recorded. Results: Thirty-one patients (all lowlanders, 19 male; age 18-60 years, median 41) had presented with acute onset breathlessness of 1-4 days (median 1.9 d) starting within 12-24 h of a rapid ascent; accompanied by cough (68%), headache (8%), dizziness and nausea (65%). Sixteen patients had associated encephalopathy. Clinical features on admission included tachypnea (n = 31), tachycardia (n = 23), bilateral chest rales (n = 29), cyanosis (n = 22) and grade 2-4 encephalopathy. Hypoxemia was demonstrable in 24 cases and bilateral infiltrates on radiologic imaging in 29. Ten patients had evidence of high-altitude cerebral edema. All patients were managed with oxygen, steroids, nifedipine, sildenafil and other supportive measures including invasive ventilation (n = 3). Three patients died due to multiorgan dysfunction. Conclusions: Altitude sickness is common among Amaranath Yatris from the plains and appropriate educational strategies should be invoked for prevention and prompt treatment. PMID:24049253

  8. [Work at high altitude: concepts of physiopathology, risk factors, health surveillance and criteria for the development of work capacity evaluation criteria].

    PubMed

    Taino, Giuseppe; Giardini, Guido; Pecchio, Oriana; Brevi, Marco; Giorgi, Marco; Verardo, Marina Giulia; Detragiaches, Enrico; Imbriani, Marcello

    2012-01-01

    Work at high altitude (elevation equal to or greater than 3000 m above sea level) results in a physiological adaptation of the human organism to changing environmental conditions. The main problem related to the altitude is represented by the reduction of partial pressure of oxygen (hypoxia) that occurs in proportion to the reduction of barometric pressure. Our study, starting with an analysis of the human body's physiological response to acute hypoxic conditions and acclimatization for reaching protracted stays, takes into consideration all risk factors related to the performance of work at high altitude. We identified risk factors related to physical environment of high altitude and represented by temperature, humidity, latitude, speed wind, atmospheric pressure and hypoxia, risk factors related to the worker and represented by age, sex, state of health and individual susceptibility, degree of training. With reference to the state of health we analyzed the major pathophysiological conditions that can create situations of susceptibility to high altitude. We then analyzed risk factors related to the characteristics of the job that are represented by the degree of physical effort and energy expenditure required, by the personal protective equipment (PPE) used and by the concomitant exposure to other occupational risk factors of physical and chemical nature. It was finally addressed the decision making process related to the formulation of the judgment of suitability for performance of work activities at high altitude. The health protocol proposed requires an accurate anamnestic investigation aimed at gathering information on pre-existing pathophysiological conditions that need, once identified, clinical and instrumental tests specific and targeted. These clinical protocols are analyzed and proposed for the main pathophysiologic conditions that pose a risk to health at high altitude. For workers, in which clinical investigation and medical history has not shown

  9. The University of Alberta High Altitude Balloon Program

    NASA Astrophysics Data System (ADS)

    Johnson, W.; Buttenschoen, A.; Farr, Q.; Hodgson, C.; Mann, I. R.; Mazzino, L.; Rae, J.; University of Alberta High Altitude Balloon Team

    2011-12-01

    The University of Alberta High Altitude Balloon (UA-HAB) program is a one and half year program sponsored by the Canadian Space Agency (CSA) that offers hands on experience for undergraduate and graduate students in the design, build, test and flight of an experimental payload on a high altitude balloon platform. Utilising low cost weather balloon platforms, and through utilisation of the CSA David Florida Laboratory for thermal-vacuum tests , in advance of the final flight of the payload on a NASA high altitude balloon platform. Collectively the program provided unique opportunities for students to experience mission phases which parallel those of a space satellite mission. The program has facilitated several weather balloon missions, which additionally provide educational opportunities for university students and staff, as well as outreach opportunities among junior and senior high school students. Weather balloon missions provide a cheap and quick alternative to suborbital missions; they can be used to test components for more expensive missions, as well as to host student based projects from different disciplines such as Earth and Atmospheric Sciences (EAS), Physics, and Engineering. In addition to extensive skills development, the program aims to promote recruitment of graduate and undergraduate students into careers in space science and engineering. Results from the UA-HAB program and the flight of the UA-HAB shielded Gieger counter payload for cosmic ray and space radiation studies will be presented. Lessons learned from developing and maintaining a weather balloon program will also be discussed. This project is undertaken in partnership with the High Altitude Student Platform, organized by Louisiana State University and the Louisiana Space Consortium (LaSpace), and sponsored by NASA, with the financial support of the Canadian Space Agency.

  10. NEW HORIZONS FOR THE NATIONAL HIGH-ALTITUDE PHOTOGRAPHY PROGRAM.

    USGS Publications Warehouse

    Bermel, Peter F.

    1983-01-01

    The National High-Altitude Photography Program (NHAP) is a multi-Federal agency activity to acquire uniform imagery for the establishment of a national high-altitude photographic data base. Since the inception of NHAP in 1980, black-and-white and color infrared stereoscopic imagery has been acquired for about 50% of the 3,000,000 square miles in the conterminous United States. An additional 40% of the 48-State area is under contract to private aerial survey firms, and the sixth and final contract to achieve complete once-over coverage will be awarded early in 1985. Extensive use has been made of the newly established data base. The participating agencies have begun studies to define the requirements for a maintenance program which would provide cyclic coverage of the conterminous United States and imagery for specific agency needs.

  11. Initial Feasibility Assessment of a High Altitude Long Endurance Airship

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony; Dolce, James (Technical Monitor)

    2003-01-01

    A high altitude solar powered airship provides the ability to carry large payloads to high altitudes and remain on station for extended periods of time. This study examines the feasibility of this concept. Factors such as time of year, latitude, wind speeds and payload are considered in establishing the capabilities of a given size airship. East and West coast operation were evaluated. The key aspect to success of this type of airship is the design and operation of the propulsion and power system. A preliminary propulsion/power system design was produced based on a regenerative fuel cell energy storage system and solar photovoltaic array for energy production. A modular system design was chosen with four independent power/propulsion units utilized by the airship. Results on payload capacity and flight envelope (latitude and time of year) were produced for a range of airship sizes.

  12. THe high altitude reconnaissance platform (HARP) and its capabilities

    SciTech Connect

    Rusk, D.; Rose, R.L.; Gibeau, E.

    1996-10-01

    The High Altitude Reconnaissance Platform (HARP), a Learjet 36A, is a multi-purpose, long-range, high-altitude aircraft specially modified to serve as a meteorological observation platform. Its instrument suite includes: particle probes, Ka-band radar, two-color lidar, infrared spectroradiometer, thermometer, hygrometer, liquid water probe, and a gust probe. Aeromet scientists have developed software and hardware systems that combine data using sensor fusion concepts, providing detailed environmental information. The HARP answers the need for defining and predicting meteorological conditions throughout large atmospheric volumes particularly in areas where conventional surface and upper-air observations are not available. It also fills the need for gathering and predicting meteorological conditions along an optical sensor`s line of sight or a missile`s reentry path. 6 refs., 2 figs., 4 tabs.

  13. Coca: High Altitude Remedy of the Ancient Incas.

    PubMed

    Biondich, Amy Sue; Joslin, Jeremy D

    2015-12-01

    The use of coca leaf for medicinal purposes is a centuries-old tradition of the native peoples of South America. Coca products are thought by many laypersons to provide risk-free benefits to users participating in strenuous activities at high altitude. Physiologic studies of coca have increased understanding of its possible mechanism of action as well as its potential impact on high altitude activities. This present work explores the role of coca throughout the history of the Andean peoples and explores whether this ancient remedy has a place in modern medicine. A focused summary of research articles with particular relevance to the field of wilderness medicine is also included to better provide the reader with lessons not only from history but also from another culture.

  14. Considerations of high altitude emissions. [from supersonic cruise aircraft

    NASA Technical Reports Server (NTRS)

    Broderick, A. J.; Krull, N. P.

    1976-01-01

    The status of the Federal Aviation Administration's High Altitude Pollution Program is described which was instituted to develop the detailed quantitative information needed to judge whether or not regulatory action to limit such exhaust emissions would be necessary. The complexities of this question and the nature and magnitude of uncertainties still present in our scientific understanding of the potential interactions between aircraft exhaust emissions and stratospheric ozone and climate are reviewed. The direction and scope of future Federal and international activities are described.

  15. Nike Black Brant V high altitude dynamic instability characteristics

    NASA Technical Reports Server (NTRS)

    Montag, W. H.; Walker, L. L., Jr.

    1979-01-01

    Flight experience on the Nike Black Brant V has demonstrated the existence of plume induced flow separation over the fins and aft body of the Black Brant V motor. Modelling of the forces associated with this phenomenon as well as analysis of the resultant vehicle coning motion and its effect on the velocity vector heading are presented. A summary of Nike Black Brant V flight experience with high altitude dynamic instability is included.

  16. [Radiation safety in flights of high-altitude aircraft].

    PubMed

    Kovalev, E E; Petrov, V M

    1975-01-01

    The major sources of radiation hazard for flights of supersonic high altitude aircraft--galactic and solar radiation--are described. Estimates of an equivalent dose rate at different distances from these sources are given. The estimates are compared with the radiation dosages allowed for the average population and special personnel. It is concluded that specific measures are needed to provide radiation safety of the crews and passengers aboard supersonic aircraft.

  17. The effect of high altitude on platelet counts, thrombopoietin and erythropoietin levels in young Bolivian airmen visiting the Andes

    NASA Astrophysics Data System (ADS)

    Hudson, J. G.; Bowen, Angela L.; Navia, Pilar; Rios-Dalenz, Jaime; Pollard, Andrew J.; Williams, David; Heath, Donald

    Recognition of thrombosis as a complication of exposure to high altitude has stimulated interest in rheological changes resulting from hypobaric hypoxia. Previous studies of platelet counts at high altitude have yielded conflicting results and have not been studied in conjunction with potential mediating cytokines. We studied the effects of high-altitude exposure on platelet numbers, thrombopoietin (tpo) and erythropoietin (epo) levels in man. A group of 28 volunteers from the Bolivian Airforce stationed at Santa Cruz (600 m altitude) were studied 48 h and 1 week after their ascent to La Paz (3600 m). In addition 105 volunteers based at Santa Cruz for at least 1 year were compared with 175 age- and sex-matched residents at El Alto (4200 m). Platelet counts were measured immediately after sampling and serum samples assayed for tpo and epo. In the ascending group, mean platelet counts were 251×109, 367×109 and 398×109/l at 600 m and following 48 h and 1 week at 3600 m respectively. Mean tpo levels were 132.5, 76 and 92 pg/ml with epo values of 2.98, 11.6 and 7.9 mIU/ml respectively. In the resident populations mean platelet counts were 271×109/l in the low- and 471×109/l in the high-altitude groups. Mean tpo and epo levels measured 69.3 pg/ml and 4.5 mIU/ml respectively at 600 m and 58.5 pg/ml and 5.1 mIU/ml at 4200 m. In conclusion we have demonstrated a significant and sustained elevation in platelet numbers within 48 h of ascent to high altitude. Our findings do not support a role for tpo as a mediator of the increased platelet count. However, these data do not discount epo as a potential candidate.

  18. Radiation safety in high-altitude air traffic

    NASA Technical Reports Server (NTRS)

    Foelsche, T.

    1977-01-01

    Results of an experimental and theoretical study on dose equivalent rates at high altitudes are presented. The flight personnel flying 500 hours per year at SST cruise altitude in high latitudes (maximum of radiation) would be exposed to less than 14% of the maximum permissible dose rate (MPD) for radiation workers (5 rem/yr), averaged over the solar cycle. One-half or more is due to energetic secondary neutrons that are penetrant and highly biologically effective. Passengers would, in general, be exposed only to the low-level galactic cosmic rays, except for a relative few who encounter rare, intense, and energetic solar-particle events. If the airplane descends to subsonic altitudes during events such as that of Feb. 23, 1956 - the most intense and unique giant energy event of the last 35 years - passenger exposure even then remains at or below permissible levels (0.5 rem for the general population). Systems of radiation monitoring are briefly discussed which will prevent false alarms and which would be useful in disproving overexposure in potential malpractice suits against the airlines. In subsonic jet transports the exposure of the crews is lower by a factor 3 to 4; for passengers it is about the same for the same distance traveled. Solar events, except for giant energy events, will yield only a minor fraction of the MPD of the general population.

  19. Key issues of ultraviolet radiation of OH at high altitudes

    SciTech Connect

    Zhang, Yuhuai; Wan, Tian; Jiang, Jianzheng; Fan, Jing

    2014-12-09

    Ultraviolet (UV) emissions radiated by hydroxyl (OH) is one of the fundamental elements in the prediction of radiation signature of high-altitude and high-speed vehicle. In this work, the OH A{sup 2}Σ{sup +}→X{sup 2}Π ultraviolet emission band behind the bow shock is computed under the experimental condition of the second bow-shock ultraviolet flight (BSUV-2). Four related key issues are discussed, namely, the source of hydrogen element in the high-altitude atmosphere, the formation mechanism of OH species, efficient computational algorithm of trace species in rarefied flows, and accurate calculation of OH emission spectra. Firstly, by analyzing the typical atmospheric model, the vertical distributions of the number densities of different species containing hydrogen element are given. According to the different dominating species containing hydrogen element, the atmosphere is divided into three zones, and the formation mechanism of OH species is analyzed in the different zones. The direct simulation Monte Carlo (DSMC) method and the Navier-Stokes equations are employed to compute the number densities of the different OH electronically and vibrationally excited states. Different to the previous work, the trace species separation (TSS) algorithm is applied twice in order to accurately calculate the densities of OH species and its excited states. Using a non-equilibrium radiation model, the OH ultraviolet emission spectra and intensity at different altitudes are computed, and good agreement is obtained with the flight measured data.

  20. High altitude impairs in vivo immunity in humans.

    PubMed

    Oliver, Samuel J; Macdonald, Jamie H; Harper Smith, Adam D; Lawley, Justin S; Gallagher, Carla A; Di Felice, Umberto; Walsh, Neil P

    2013-06-01

    The aim was to assess the effect of high altitude on the development of new immune memory (induction) using a contact sensitization model of in vivo immunity. We hypothesized that high-altitude exposure would impair induction of the in vivo immune response to a novel antigen, diphenylcyclopropenone (DPCP). DPCP was applied (sensitization) to the lower back of 27 rested controls at sea level and to ten rested mountaineers 28 hours after passive ascent to 3777 m. After sensitization, mountaineers avoided strenuous exercise for a further 24 hours, after which they completed alpine activities for 11-18 days. Exactly 4 weeks after sensitization, the strength of immune memory induction was quantified in rested mountaineers and controls at sea level, by measuring the response to a low, dose-series DPCP challenge, read at 48 hours as skin measures of edema (skinfold thickness) and redness (erythema). Compared with control responses, skinfold thickness and erythema were reduced in the mountaineers (skinfold thickness,-52%, p=0.01, d=0.86; erythema, -36%, p=0.02, d=0.77). These changes in skinfold thickness and erythema were related to arterial oxygen saturation (r=0.7, p=0.04), but not cortisol (r<0.1, p>0.79), at sensitization. In conclusion, this is the first study to show, using a contact sensitization model of in vivo immunity, that high altitude exposure impairs the development of new immunity in humans.

  1. Reference values for pulse oximetry at high altitude

    PubMed Central

    Gamponia, M; Babaali, H; Yugar, F; Gilman, R

    1998-01-01

    OBJECTIVE—To determine reference values for oxygen saturation (SaO2) in healthy children younger than 5 years living at high altitude.
DESIGN—One hundred and sixty eight children were examined for SaO2 at 4018 m during well child visits. Physiological state was also noted during the examination.
RESULTS—The mean SaO2 was 87.3% (95% confidence intervals (CI) 86.7%, 87.9%) with a median value of 87.7%. A significant difference was observed in SaO2 between children younger than 1 year compared with older children, although the difference was no longer demonstrable when sleeping children were excluded.
CONCLUSIONS—This study has provided a reference range of SaO2 values for healthy children under 5 years old so that pulse oximetry may be used as an adjunct in diagnosing acute respiratory infections. Younger children were also shown to have a lower mean SaO2 than older children living at high altitude, which suggests physiological adaptation to high altitude over time. In addition, sleep had a lowering effect on SaO2, although the clinical importance of this remains undetermined.

 PMID:9659095

  2. A High Altitude-Low Reynolds Number Aerodynamic Flight Experiment

    NASA Technical Reports Server (NTRS)

    Greer, Don; Krake, Keith; Hamory, Phil; Drela, Mark; Lee, Seunghee (Technical Monitor)

    1999-01-01

    A sailplane is currently being developed at NASA's Dryden Flight Research Center to support a high altitude flight experiment. The purpose of the experiment is to measure the performance characteristics of an airfoil at altitudes between 100,000 and 70,000 feet at Mach numbers between 0.65 and 0.5. The airfoil lift and drag are measured from pilot and static pressures. The location of the separation bubble and vortex shedding are measured from a hot film strip. The details of the flight experiment are presented. A comparison of several estimates of the airfoil performance is also presented. The airfoil, APEX-16, was designed by Drela (MIT) with his MSES code. A two dimensional Navier-Stokes analysis has been performed by Tatineni and Zhong (UCLA) and another at the Dryden Flight Research Center. The role these analysis served to define the experiment is discussed.

  3. Applications of a high-altitude powered platform /HAPP/

    NASA Technical Reports Server (NTRS)

    Kuhner, M. B.

    1979-01-01

    The high-altitude powered platform (HAPP) is a conceptual unmanned vehicle which could be either an airship or airplane. It would keep station at an altitude of 70,000 ft above a fixed point on the ground. A microwave power transmission system would beam energy from the ground up to the HAPP to power an electric motor-driven propeller and the payload. A study of the HAPP has shown that it could potentially be a cost-competitive platform for such remote sensing applications as forest fire detection, Great Lakes ice monitoring and Coast Guard law enforcement. It also has significant potential as a communications relay platform for (among other things) direct broadcast to home TVs over a large region.

  4. Paleoindian settlement of the high-altitude Peruvian Andes.

    PubMed

    Rademaker, Kurt; Hodgins, Gregory; Moore, Katherine; Zarrillo, Sonia; Miller, Christopher; Bromley, Gordon R M; Leach, Peter; Reid, David A; Álvarez, Willy Yépez; Sandweiss, Daniel H

    2014-10-24

    Study of human adaptation to extreme environments is important for understanding our cultural and genetic capacity for survival. The Pucuncho Basin in the southern Peruvian Andes contains the highest-altitude Pleistocene archaeological sites yet identified in the world, about 900 meters above confidently dated contemporary sites. The Pucuncho workshop site [4355 meters above sea level (masl)] includes two fishtail projectile points, which date to about 12.8 to 11.5 thousand years ago (ka). Cuncaicha rock shelter (4480 masl) has a robust, well-preserved, and well-dated occupation sequence spanning the past 12.4 thousand years (ky), with 21 dates older than 11.5 ka. Our results demonstrate that despite cold temperatures and low-oxygen conditions, hunter-gatherers colonized extreme high-altitude Andean environments in the Terminal Pleistocene, within about 2 ky of the initial entry of humans to South America. PMID:25342802

  5. Neutron radiation dosimetry in high altitude flight personnel.

    PubMed

    Baily, P E

    1982-08-01

    In an attempt to determine cosmic radiation exposure in high altitude NASA flight personnel, eight WB-57F flight crewmen were monitored for a period of six months using a combination radiation dosimeter. Each dosimeter consisted of two thermoluminescent chips capable of measuring gamma dose and one Albedo and two Track Etch neutron dosimeters. A total of 78 flights were monitored consisting of 251 flight hours at altitudes above 14 km (45,000 ft). The maximum yearly dose equivalent measured was 104 mrem, a value well below the Maximum Permissible Dose (MPD) of 5.0 rem/y for occupational exposures and 0.5 rem/y for members of the general public. A discussion of the theory and use of several types of neutron dosimeters is included. PMID:7181814

  6. AltitudeOmics: on the consequences of high-altitude acclimatization for the development of fatigue during locomotor exercise in humans.

    PubMed

    Amann, Markus; Goodall, Stuart; Twomey, Rosie; Subudhi, Andrew W; Lovering, Andrew T; Roach, Robert C

    2013-09-01

    The development of muscle fatigue is oxygen (O2)-delivery sensitive [arterial O2 content (CaO2) × limb blood flow (QL)]. Locomotor exercise in acute hypoxia (AH) is, compared with sea level (SL), associated with reduced CaO2 and exaggerated inspiratory muscle work (Winsp), which impairs QL, both of which exacerbate fatigue individually by compromising O2 delivery. Since chronic hypoxia (CH) normalizes CaO2 but exacerbates Winsp, we investigated the consequences of a 14-day exposure to high altitude on exercise-induced locomotor muscle fatigue. Eight subjects performed the identical constant-load cycling exercise (138 ± 14 W; 11 ± 1 min) at SL (partial pressure of inspired O2, 147.1 ± 0.5 Torr), in AH (73.8 ± 0.2 Torr), and in CH (75.7 ± 0.1 Torr). Peripheral fatigue was expressed as pre- to postexercise percent reduction in electrically evoked potentiated quadriceps twitch force (ΔQtw,pot). Central fatigue was expressed as the exercise-induced percent decrease in voluntary muscle activation (ΔVA). Resting CaO2 at SL and CH was similar, but CaO2 in AH was lower compared with SL and CH (17.3 ± 0.5, 19.3 ± 0.7, 20.3 ± 1.3 ml O2/dl, respectively). Winsp during exercise increased with acclimatization (SL: 387 ± 36, AH: 503 ± 53, CH: 608 ± 67 cmH2O·s(-1)·min(-1); P < 0.01). Exercise at SL did not induce central or peripheral fatigue. ΔQtw,pot was significant but similar in AH and CH (21 ± 2% and 19 ± 3%; P = 0.24). ΔVA was significant in both hypoxic conditions but smaller in CH vs. AH (4 ± 1% vs. 8 ± 2%; P < 0.05). In conclusion, acclimatization to severe altitude does not attenuate the substantial impact of hypoxia on the development of peripheral fatigue. In contrast, acclimatization attenuates, but does not eliminate, the exacerbation of central fatigue associated with exercise in severe AH.

  7. Atmospheric Sampling of Aerosols to Stratospheric Altitudes using High Altitude Balloons

    NASA Astrophysics Data System (ADS)

    Jerde, E. A.; Thomas, E.

    2010-12-01

    Although carbon dioxide represents a long-lived atmospheric component relevant to global climate change, it is also understood that many additional contributors influence the overall climate of Earth. Among these, short-lived components are more difficult to incorporate into models due to uncertainties in the abundances of these both spatially and temporally. Possibly the most significant of these short-lived components falls under the heading of “black carbon” (BC). There are numerous overlapping definitions of BC, but it is basically carbonaceous in nature and light absorbing. Due to its potential as a climate forcer, an understanding of the BC population in the atmosphere is critical for modeling of radiative forcing. Prior measurements of atmospheric BC generally consist of airplane- and ground-based sampling, typically below 5000 m and restricted in time and space. Given that BC has a residence time on the order of days, short-term variability is easily missed. Further, since the radiative forcing is a result of BC distributed through the entire atmospheric column, aircraft sampling is by definition incomplete. We are in the process of planning a more comprehensive sampling of the atmosphere for BC using high-altitude balloons. Balloon-borne sampling is a highly reliable means to sample air through the entire troposphere and into the lower stratosphere. Our system will incorporate a balloon and a flight train of two modules. One module will house an atmospheric sampler. This sampler will be single-stage (samples all particle sizes together), and will place particles directly on an SEM sample stub for analysis. The nozzle depositing the sample will be offset from the center of the stub, placing the aerosol particles toward the edge. At various altitudes, the stub will be rotated 45 degrees, providing 6-8 sample “cuts” of particle populations through the atmospheric column. The flights will reach approximately 27 km altitude, above which the balloons

  8. High altitude smoke in the NASA GISS GCM

    NASA Technical Reports Server (NTRS)

    Field, Robert; Luo, M.; Fromm, M.; Voulgarakis, A.; Mangeon, S.; Worden, J.

    2015-01-01

    High altitude smoke-plumes from large, explosive fires were discovered in the late 1990sThey can now be observed with unprecedented detail from space-borne instruments with high vertical resolution in the UTLS such as CALIOP, MLS and ACE. These events inject large quantities of pollutants into a relatively clean and dry environment They serve as unique natural experiments with which to understand, using chemical transport and composition-climate models, the chemical and radiative impacts of long-lived biomass burning emissions. We are currently studying the Black Saturday bushfires in Australia during February 2009

  9. High Altitude Venus Operations Concept Trajectory Design, Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Lugo, Rafael A.; Ozoroski, Thomas A.; Van Norman, John W.; Arney, Dale C.; Dec, John A.; Jones, Christopher A.; Zumwalt, Carlie H.

    2015-01-01

    A trajectory design and analysis that describes aerocapture, entry, descent, and inflation of manned and unmanned High Altitude Venus Operation Concept (HAVOC) lighter-than-air missions is presented. Mission motivation, concept of operations, and notional entry vehicle designs are presented. The initial trajectory design space is analyzed and discussed before investigating specific trajectories that are deemed representative of a feasible Venus mission. Under the project assumptions, while the high-mass crewed mission will require further research into aerodynamic decelerator technology, it was determined that the unmanned robotic mission is feasible using current technology.

  10. Stratochip, a dual balloon high-altitude platform: controlled altitude flight experiments and potential applications in geosciences.

    NASA Astrophysics Data System (ADS)

    Burlet, Christian; Vanbrabant, Yves

    2014-05-01

    A high-altitude dual balloons system, the 'Stratochip', was designed at the Geological Survey of Belgium to serve as a development platform to carry measurement and earth observation equipments, in altitudes comprised between 1000 and 25000m. These working altitudes far exceed the range of current motor powered unmanned aerial vehicules, with a higher weight carrying capacity (up to 10-15kg). This platform is built around a two helium balloons configuration, than can be released one by one at a target altitude or location, allowing a partially controlled drift of the platform. Using a 'nowcasting' meteorological model, updated by flight telemetry, the predicted path can be refined live to follow and retrieve the equipment in a predicted landing area. All subsystems (balloon cut-off devices, flight controller, telemetry system) have been developed in-house. Three independent communication channels, designed to work at extremely low temperature (up to -60° C) ensure a continuous tracking until landing. A calibrated parachute is used to control the safe descent of the equipment. Several flight tests have been performed in Belgium to control the meteorological model accuracy for wind predictions (model based on National Oceanic and Atmospheric Administration data). Those tests demonstrated the capability of the platform to maintain its altitude in a predicted path, allowing using the platform for new types of atmospheric studies and affordable high-altitude remote-sensing applications (i.e. sub-meter resolution stereo imagery).

  11. Long-Term Exposure to High Altitude Affects Response Inhibition in the Conflict-monitoring Stage.

    PubMed

    Ma, Hailin; Wang, Yan; Wu, Jianhui; Luo, Ping; Han, Buxin

    2015-09-01

    To investigate the effects of high-altitude exposure on response inhibition, event-related potential (ERP) components N2 and P3 were measured in Go/NoGo task. The participants included an 'immigrant' high-altitude group (who had lived at high altitude for three years but born at low altitude) and a low-altitude group (living in low altitude only). Although the behavioural data showed no significant differences between the two groups, a delayed latency of NoGo-N2 was found in the high-altitude group compared to the low-altitude group. Moreover, larger N2 and smaller P3 amplitudes were found in the high-altitude group compared to the low-altitude group, for both the Go and NoGo conditions. These findings suggest that high-altitude exposure affects response inhibition with regard to processing speed during the conflict monitoring stage. In addition, high altitude generally increases the neural activity in the matching step of information processing and attentional resources. These results may provide some insights into the neurocognitive basis of the effects on high-altitude exposure on response inhibition.

  12. Long-Term Exposure to High Altitude Affects Response Inhibition in the Conflict-monitoring Stage.

    PubMed

    Ma, Hailin; Wang, Yan; Wu, Jianhui; Luo, Ping; Han, Buxin

    2015-01-01

    To investigate the effects of high-altitude exposure on response inhibition, event-related potential (ERP) components N2 and P3 were measured in Go/NoGo task. The participants included an 'immigrant' high-altitude group (who had lived at high altitude for three years but born at low altitude) and a low-altitude group (living in low altitude only). Although the behavioural data showed no significant differences between the two groups, a delayed latency of NoGo-N2 was found in the high-altitude group compared to the low-altitude group. Moreover, larger N2 and smaller P3 amplitudes were found in the high-altitude group compared to the low-altitude group, for both the Go and NoGo conditions. These findings suggest that high-altitude exposure affects response inhibition with regard to processing speed during the conflict monitoring stage. In addition, high altitude generally increases the neural activity in the matching step of information processing and attentional resources. These results may provide some insights into the neurocognitive basis of the effects on high-altitude exposure on response inhibition. PMID:26324166

  13. An Undergraduate-Built Prototype Altitude Determination System (PADS) for High Altitude Research Balloons.

    NASA Astrophysics Data System (ADS)

    Verner, E.; Bruhweiler, F. C.; Abot, J.; Casarotto, V.; Dichoso, J.; Doody, E.; Esteves, F.; Morsch Filho, E.; Gonteski, D.; Lamos, M.; Leo, A.; Mulder, N.; Matubara, F.; Schramm, P.; Silva, R.; Quisberth, J.; Uritsky, G.; Kogut, A.; Lowe, L.; Mirel, P.; Lazear, J.

    2014-12-01

    In this project a multi-disciplinary undergraduate team from CUA, comprising majors in Physics, Mechanical Engineering, Electrical Engineering, and Biology, design, build, test, fly, and analyze the data from a prototype attitude determination system (PADS). The goal of the experiment is to determine if an inexpensive attitude determination system could be built for high altitude research balloons using MEMS gyros. PADS is a NASA funded project, built by students with the cooperation of CUA faculty, Verner, Bruhweiler, and Abot, along with the contributed expertise of researchers and engineers at NASA/GSFC, Kogut, Lowe, Mirel, and Lazear. The project was initiated through a course taught in CUA's School of Engineering, which was followed by a devoted effort by students during the summer of 2014. The project is an experiment to use 18 MEMS gyros, similar to those used in many smartphones, to produce an averaged positional error signal that could be compared with the motion of the fixed optical system as recorded through a string of optical images of stellar fields to be stored on a hard drive flown with the experiment. The optical system, camera microprocessor, and hard drive are enclosed in a pressure vessel, which maintains approximately atmospheric pressure throughout the balloon flight. The experiment uses multiple microprocessors to control the camera exposures, record gyro data, and provide thermal control. CUA students also participated in NASA-led design reviews. Four students traveled to NASA's Columbia Scientific Balloon Facility in Palestine, Texas to integrate PADS into a large balloon gondola containing other experiments, before being shipped, then launched in mid-August at Ft. Sumner, New Mexico. The payload is to fly at a float altitude of 40-45,000 m, and the flight last approximately 15 hours. The payload is to return to earth by parachute and the retrieved data are to be analyzed by CUA undergraduates. A description of the instrument is presented

  14. 40 CFR Appendix III to Part 1068 - High-Altitude Counties

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false High-Altitude Counties III Appendix... Appendix III to Part 1068—High-Altitude Counties In some cases the standard-setting part includes requirements or other specifications that apply for high-altitude counties. The following counties...

  15. 40 CFR Appendix III to Part 1068 - High-Altitude Counties

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false High-Altitude Counties III Appendix... Appendix III to Part 1068—High-Altitude Counties In some cases the standard-setting part includes requirements or other specifications that apply for high-altitude counties. The following counties...

  16. 40 CFR Appendix III to Part 1068 - High-Altitude Counties

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false High-Altitude Counties III Appendix...—High-Altitude Counties In some cases the standard-setting part includes requirements or other specifications that apply for high-altitude counties. The following counties have substantial populated...

  17. 40 CFR Appendix III to Part 1068 - High-Altitude Counties

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false High-Altitude Counties III Appendix... Appendix III to Part 1068—High-Altitude Counties In some cases the standard-setting part includes requirements or other specifications that apply for high-altitude counties. The following counties...

  18. Lightweight Liquid Helium Dewar for High-Altitude Balloon Payloads

    NASA Technical Reports Server (NTRS)

    Kogut, Alan; James, Bryan; Fixsen, Dale

    2013-01-01

    Astrophysical observations at millimeter wavelengths require large (2-to-5- meter diameter) telescopes carried to altitudes above 35 km by scientific research balloons. The scientific performance is greatly enhanced if the telescope is cooled to temperatures below 10 K with no emissive windows between the telescope and the sky. Standard liquid helium bucket dewars can contain a suitable telescope for telescope diameter less than two meters. However, the mass of a dewar large enough to hold a 3-to-5-meter diameter telescope would exceed the balloon lift capacity. The solution is to separate the functions of cryogen storage and in-flight thermal isolation, utilizing the unique physical conditions at balloon altitudes. Conventional dewars are launched cold: the vacuum walls necessary for thermal isolation must also withstand the pressure gradient at sea level and are correspondingly thick and heavy. The pressure at 40 km is less than 0.3% of sea level: a dewar designed for use only at 40 km can use ultra thin walls to achieve significant reductions in mass. This innovation concerns new construction and operational techniques to produce a lightweight liquid helium bucket dewar. The dewar is intended for use on high-altitude balloon payloads. The mass is low enough to allow a large (3-to-5-meter) diameter dewar to fly at altitudes above 35 km on conventional scientific research balloons without exceeding the lift capability of the balloon. The lightweight dewar has thin (250- micron) stainless steel walls. The walls are too thin to support the pressure gradient at sea level: the dewar launches warm with the vacuum space vented continuously during ascent to eliminate any pressure gradient across the walls. A commercial 500-liter storage dewar maintains a reservoir of liquid helium within a minimal (hence low mass) volume. Once a 40-km altitude is reached, the valve venting the vacuum space of the bucket dewar is closed to seal the vacuum space. A vacuum pump then

  19. [Sperm count and seminal biochemistry of high altitude inhabitants and patients with chronic altitude sickness].

    PubMed

    García-Hjarles, M A

    1989-04-01

    Semen analysis has been studied in 9 healthy adult males from sea level (150 m), age 19-32 years old and 15 healthy males from high altitude (NA), 9 from Cerro de Pasco (4,300 m) and 6 from Morococha (4,540 m), ages 19-45 years old. Five patients with chronic mountain sickness (MMC), whose ages ranged from 23 to 52 years old were also studied. The volume and motility were similar in NA and MMC, however both were below than in sea level subjects, but still in the normal range; the number of spermatozoa per 1 ml was lower at sea level than in NA and MMC, although the total number was higher at sea level due to the higher semen volume. Fructose at sea level was 356 +/- 53 mg/100 ml (mean +/- S.E.) which is similar to NA 237 +/- 45 whereas a MMC was significantly lower, 142 +/- 60. Citric acid was lower at sea level than in NA and MMC. Na, K and Cl, were similar among the three groups. The lower concentration of fructose in MMC parallels the decreased testicular function already found in these groups. However it is worthy to point out that the fertility is preserved in all the groups. The normal reproductive function in MMC is against the concept that this process occurs as a consequence of environmental disadaptation.

  20. the APL Balloonborne High Altitude Research Platform (HARP)

    NASA Astrophysics Data System (ADS)

    Adams, D.; Arnold, S.; Bernasconi, P.

    2015-09-01

    The Johns Hopkins University Applied Physics Laboratory (APL) has developed and demonstrated a multi-purpose stratospheric balloonborne gondola known as the High Altitude Research Platform (HARP). HARP provides the power, mechanical supports, thermal control, and data transmission for multiple forms of high-altitude scientific research equipment. The platform has been used for astronomy, cosmology and heliophysics experiments but can also be applied to atmospheric studies, space weather and other forms of high altitude research. HARP has executed five missions. The first was Flare Genesis from Antarctica in 1993 and the most recent was the Balloon Observation Platform for Planetary Science (BOPPS) from New Mexico in 2014. HARP will next be used to perform again the Stratospheric Terahertz Observatory mission, a mission that it first performed in 2009. The structure, composed of an aluminum framework is designed for easy transport and field assembly while providing ready access to the payload and supporting avionics. A light-weighted structure, capable of supporting Ultra-Long Duration Balloon (ULDB) flights that can last more than 100 days is available. Scientific research payloads as heavy as 600 kg (1322 pounds) and requiring up to 800 Watts electrical power can be supported. The platform comprises all subsystems required to support and operate the science payload, including both line-of-sight (LOS) and over-the-horizon (0TH) telecommunications, the latter provided by Iridium Pilot. Electrical power is produced by solar panels for multi-day missions and batteries for single-day missions. The avionics design is primarily single-string; however, use of ruggedized industrial components provides high reliability. The avionics features a Command and Control (C&C) computer and a Pointing Control System (PCS) computer housed within a common unpressurized unit. The avionics operates from ground pressure to 2 Torr and over a temperature range from —30 C to +85 C

  1. Downregulation of duodenal SLC transporters and activation of proinflammatory signaling constitute the early response to high altitude in humans.

    PubMed

    Wojtal, Kacper A; Cee, Alexandra; Lang, Silvia; Götze, Oliver; Frühauf, Heiko; Geier, Andreas; Pastor-Anglada, Marçal; Torres-Torronteras, Javier; Martí, Ramon; Fried, Michael; Lutz, Thomas A; Maggiorini, Marco; Gassmann, Max; Rogler, Gerhard; Vavricka, Stephan R

    2014-10-01

    Solute carrier (SLC) transporters mediate the uptake of biologically active compounds in the intestine. Reduced oxygenation (hypoxia) is an important factor influencing intestinal homeostasis. The aim of this study was to investigate the pathophysiological consequences of hypoxia on the expression and function of SLCs in human intestine. Hypoxia was induced in human intestinal epithelial cells (IECs) in vitro (0.2; 1% O2 or CoCl2). For human in vivo studies, duodenal biopsies and serum samples were obtained from individuals (n = 16) acutely exposed to 4,554 meters above sea levels. Expression of relevant targets was analyzed by quantitative PCR, Western blotting, or immunofluorescence. Serum levels of inflammatory mediators and nucleosides were determined by ELISA and LC/MS-MS, respectively. In the duodenum of volunteers exposed to high altitude we observed decreased mRNA levels of apical sodium-dependent bile acid transporter (ASBT), concentrative nucleoside transporters 1/2 (CNT1/2), organic anion transporting polypeptide 2B1 (OATP2B1), organic cation transporter 2 (OCTN2), peptide transporter 1 (PEPT1), serotonin transporter (SERT), and higher levels of IFN-γ, IL-6, and IL-17A. Serum levels of IL-10, IFN-γ, matrix metalloproteinase-2 (MMP-2), and serotonin were elevated, whereas the levels of uridine decreased upon exposure to hypoxia. Hypoxic IECs showed reduced levels of equilibrative nucleoside transporter 2 (ENT2), OCTN2, and SERT mRNAs in vitro, which was confirmed on the protein level and was accompanied by activation of ERK1/2, increase of hypoxia-inducible factor (HIF) proteins, and production of IL-8 mRNA. Costimulation with IFN-γ and IL-6 during hypoxia further decreased the expression of SERT, ENT2, and CNT2 in vitro. Reduced oxygen supply affects the expression pattern of duodenal SLCs that is accompanied by changes in serum levels of proinflammatory cytokines and biologically active compounds demonstrating that intestinal transport is affected

  2. Effects of hypoxia on diaphragmatic fatigue in highly trained athletes.

    PubMed

    Vogiatzis, Ioannis; Georgiadou, Olga; Koskolou, Maria; Athanasopoulos, Dimitrios; Kostikas, Konstantinos; Golemati, Spyretta; Wagner, Harrieth; Roussos, Charis; Wagner, Peter D; Zakynthinos, Spyros

    2007-05-15

    Previous work suggests that exercise-induced arterial hypoxaemia (EIAH), causing only moderate arterial oxygen desaturation (SaO2 : 92 +/- 1%), does not exaggerate diaphragmatic fatigue exhibited by highly trained endurance athletes. Since changes in arterial O2 tension have a significant effect on the rate of development of locomotor muscle fatigue during strenuous exercise, the present study investigated whether hypoxia superimposed on EIAH exacerbates the exercise-induced diaphragmatic fatigue in these athletes. Eight trained cyclists (VO2max : 67.0 +/- 2.6 ml kg(-1) min(-1); mean +/- S.E.M.) completed in balanced order four 5 min exercise tests leading to different levels of end-exercise SaO2 (64 +/- 2, 83 +/- 1, 91 +/- 1 and 96 +/- 1%) via variations in inspired O2 fraction (FiO2 : 0.13, 0.17, 0.21 and 0.26, respectively). Measurements were made at corresponding intensities (65 +/- 3, 80 +/- 3, 85 +/- 3 and 90 +/- 3% of normoxic maximal work rate, respectively) in order to produce the same tidal volume, breathing frequency and respiratory muscle load at each FiO2. The mean pressure time product of the diaphragm did not differ across the four exercise tests and ranged between 312 +/- 28 and 382 +/- 22 cmH2O s min(-1). Ten minutes into recovery, twitch transdiaphragmatic pressure (P(di,tw)) determined by bilateral phrenic nerve stimulation, was significantly (P = 0.0001) reduced after all tests. After both hypoxic tests (FiO2 : 0.13, 0.17) the degree of fall in P(di,tw) (by 26.9 +/- 2.7 and 27.4 +/- 2.6%, respectively) was significantly greater (P < 0.05) than after the normoxic test (by 20.1 +/- 3.4%). The greater amount of diaphragmatic fatigue in hypoxia at lower leg work rates (presumably requiring smaller leg blood flow compared with normoxia at higher leg work rates), suggests that when ventilatory muscle load is similar between normoxia and hypoxia, hypoxia exaggerates diaphragmatic fatigue in spite of potentially greater respiratory muscle blood flow

  3. NGC 1252: a high altitude, metal poor open cluster remnant

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, R.; de la Fuente Marcos, C.; Moni Bidin, C.; Carraro, G.; Costa, E.

    2013-09-01

    If stars form in clusters but most stars belong to the field, understanding the details of the transition from the former to the latter is imperative to explain the observational properties of the field. Aging open clusters are one of the sources of field stars. The disruption rate of open clusters slows down with age but, as an object gets older, the distinction between the remaining cluster or open cluster remnant (OCR) and the surrounding field becomes less and less obvious. As a result, finding good OCR candidates or confirming the OCR nature of some of the best candidates still remain elusive. One of these objects is NGC 1252, a scattered group of about 20 stars in Horologium. Here we use new wide-field photometry in the UBVI passbands, proper motions from the Yale/San Juan SPM 4.0 catalogue and high-resolution spectroscopy concurrently with results from N-body simulations to decipher NGC 1252's enigmatic character. Spectroscopy shows that most of the brightest stars in the studied area are chemically, kinematically and spatially unrelated to each other. However, after analysing proper motions, we find one relevant kinematic group. This sparse object is relatively close (˜1 kpc), metal poor and is probably not only one of the oldest clusters (3 Gyr) within 1.5 kpc from the Sun but also one of the clusters located farthest from the disc, at an altitude of nearly -900 pc. That makes NGC 1252 the first open cluster that can be truly considered a high Galactic altitude OCR: an unusual object that may hint at a star formation event induced on a high Galactic altitude gas cloud. We also conclude that the variable TW Horologii and the blue straggler candidate HD 20286 are unlikely to be part of NGC 1252. NGC 1252 17 is identified as an unrelated, Population II cannonball star moving at about 400 km s-1.

  4. [Aviation and high-altitude medicine for anaesthetists: part 1: physical basics and pathophysiology].

    PubMed

    Pump, Stefan; Stüben, Uwe; Graf, Jürgen

    2012-11-01

    Air travel has become a natural part of modern life. Both the environment, they take place in and the physical changes humans are exposed to must not be underestimated. Changes of pressure and volume of gases in higher altitudes induce specific physiological reactions, whereas limitations to compensate need to be acknowledged. It is the artificial environment of the aircraft cabin that allows travel in usual flight levels. Nevertheless, mild hypoxia and its sequeale have to be considered. PMID:23235898

  5. Preliminary results of MUNDO high altitude pressure measurements

    SciTech Connect

    Banister, J.R.; Hereford, W.V.; Solomon, O.M.

    1987-01-01

    Four high altitude pressure measurement canisters were deployed for the MUNDO event. All canister parachutes deployed and the placement of instruments was quite satisfactory in spite of an unusual wind change. Fouled leak plugs caused the two intermediate pressure transducers to be driven out of range but a new and reasonably successful procedure was developed for recovering the pressure histories of these canisters from acceleration histories. The measurements bridged across from the central radiation cone to the transition region. Pressure levels and pressure histories at outer stations are atypical with the unexpected appearances of shock fronts. Pressure histories were more complicated with peak pressures lower than observed on RUMMY.

  6. Modelling of radiation exposure at high altitudes during solar storms.

    PubMed

    Al Anid, H; Lewis, B J; Bennett, L G I; Takada, M

    2009-10-01

    A transport code analysis using Monte Carlo N-Particle eXtended code, MCNPX, has been used to propagate an extrapolated particle spectrum based on satellite measurements through the atmosphere to estimate radiation exposure during solar storms at high altitudes. Neutron monitor count rate data from stations around the world were used to benchmark the model calculations during a ground-level event (GLE). A comparison was made between the model predictions and actual flight measurements taken with various types of instruments used to measure the mixed radiation field during GLE 60. A computer code has been developed to implement the model for routine analysis.

  7. Human Behaviour and Development under High-Altitude Conditions

    ERIC Educational Resources Information Center

    Virues-Ortega, Javier; Garrido, Eduardo; Javierre, Casimiro; Kloezeman, Karen C.

    2006-01-01

    Although we are far from a universally accepted pattern of impaired function at altitude, there is evidence indicating motor, perceptual, memory and behavioural deficits in adults. Even relatively low altitudes (2500 m) may delay reaction time, and impair motor function. Extreme altitude exposure (greater than 5000 m) may result in more pronounced…

  8. Altitude acclimatization. Citations from the International Aerospace Abstracts data base

    NASA Technical Reports Server (NTRS)

    Mauk, S. C.

    1980-01-01

    This bibliography of citations to the international literature covers aspects of altitude acclimatization. Included are articles concerning high altitude environments, hypoxia, heart function and hemodynamic responses, physical exercise, human tolerances and reactions, physiological responses, and oxygen consumption. This updated bibliography contains 164 citations, 35 of which are new entries to the previous edition.

  9. Wide distribution and altitude correlation of an archaic high-altitude-adaptive EPAS1 haplotype in the Himalayas.

    PubMed

    Hackinger, Sophie; Kraaijenbrink, Thirsa; Xue, Yali; Mezzavilla, Massimo; Asan; van Driem, George; Jobling, Mark A; de Knijff, Peter; Tyler-Smith, Chris; Ayub, Qasim

    2016-04-01

    High-altitude adaptation in Tibetans is influenced by introgression of a 32.7-kb haplotype from the Denisovans, an extinct branch of archaic humans, lying within the endothelial PAS domain protein 1 (EPAS1), and has also been reported in Sherpa. We genotyped 19 variants in this genomic region in 1507 Eurasian individuals, including 1188 from Bhutan and Nepal residing at altitudes between 86 and 4550 m above sea level. Derived alleles for five SNPs characterizing the core Denisovan haplotype (AGGAA) were present at high frequency not only in Tibetans and Sherpa, but also among many populations from the Himalayas, showing a significant correlation with altitude (Spearman's correlation coefficient = 0.75, p value 3.9 × 10(-11)). Seven East- and South-Asian 1000 Genomes Project individuals shared the Denisovan haplotype extending beyond the 32-kb region, enabling us to refine the haplotype structure and identify a candidate regulatory variant (rs370299814) that might be interacting in an additive manner with the derived G allele of rs150877473, the variant previously associated with high-altitude adaptation in Tibetans. Denisovan-derived alleles were also observed at frequencies of 3-14% in the 1000 Genomes Project African samples. The closest African haplotype is, however, separated from the Asian high-altitude haplotype by 22 mutations whereas only three mutations, including rs150877473, separate the Asians from the Denisovan, consistent with distant shared ancestry for African and Asian haplotypes and Denisovan adaptive introgression.

  10. Revisiting the Cause of Focal Neurological Deficits and Profound Dyspnea at High Altitude-The Potential Role of Patent Foramen Ovale.

    PubMed

    Murdoch, David R

    2015-12-01

    A 49-year-old man developed weakness due to acute infarction of the left precentral gyrus. Subsequent investigation revealed a large patent foramen ovale (PFO), and it was concluded that the cerebral infarction was likely caused by a paradoxical embolus in association with the PFO. In hindsight, the PFO may explain several previous transient focal neurological deficits, some of which had occurred at high altitude and had been attributed to migraine. Furthermore, the large PFO may explain several episodes of profound shortness of breath that had occurred while exercising at high altitude during his lifetime, typically above 5000 m. Arterial hypoxemia due to hypobaric hypoxia may be exacerbated in individuals with PFO and affect physical performance at high altitude.

  11. Comparison of “Live High-Train Low” in Normobaric versus Hypobaric Hypoxia

    PubMed Central

    Saugy, Jonas J.; Schmitt, Laurent; Cejuela, Roberto; Faiss, Raphael; Hauser, Anna; Wehrlin, Jon P.; Rudaz, Benjamin; Delessert, Audric; Robinson, Neil; Millet, Grégoire P.

    2014-01-01

    We investigated the changes in both performance and selected physiological parameters following a Live High-Train Low (LHTL) altitude camp in either normobaric hypoxia (NH) or hypobaric hypoxia (HH) replicating current “real” practices of endurance athletes. Well-trained triathletes were split into two groups (NH, n = 14 and HH, n = 13) and completed an 18-d LHTL camp during which they trained at 1100–1200 m and resided at an altitude of 2250 m (PiO2  = 121.7±1.2 vs. 121.4±0.9 mmHg) under either NH (hypoxic chamber; FiO2 15.8±0.8%) or HH (real altitude; barometric pressure 580±23 mmHg) conditions. Oxygen saturations (SpO2) were recorded continuously daily overnight. PiO2 and training loads were matched daily. Before (Pre-) and 1 day after (Post-) LHTL, blood samples, VO2max, and total haemoglobin mass (Hbmass) were measured. A 3-km running test was performed near sea level twice before, and 1, 7, and 21 days following LHTL. During LHTL, hypoxic exposure was lower for the NH group than for the HH group (220 vs. 300 h; P<0.001). Night SpO2 was higher (92.1±0.3 vs. 90.9±0.3%, P<0.001), and breathing frequency was lower in the NH group compared with the HH group (13.9±2.1 vs. 15.5±1.5 breath.min−1, P<0.05). Immediately following LHTL, similar increases in VO2max (6.1±6.8 vs. 5.2±4.8%) and Hbmass (2.6±1.9 vs. 3.4±2.1%) were observed in NH and HH groups, respectively, while 3-km performance was not improved. However, 21 days following the LHTL intervention, 3-km run time was significantly faster in the HH (3.3±3.6%; P<0.05) versus the NH (1.2±2.9%; ns) group. In conclusion, the greater degree of race performance enhancement by day 21 after an 18-d LHTL camp in the HH group was likely induced by a larger hypoxic dose. However, one cannot rule out other factors including differences in sleeping desaturations and breathing patterns, thus suggesting higher hypoxic stimuli in the HH group. PMID:25517507

  12. Comparison of "Live High-Train Low" in normobaric versus hypobaric hypoxia.

    PubMed

    Saugy, Jonas J; Schmitt, Laurent; Cejuela, Roberto; Faiss, Raphael; Hauser, Anna; Wehrlin, Jon P; Rudaz, Benjamin; Delessert, Audric; Robinson, Neil; Millet, Grégoire P

    2014-01-01

    We investigated the changes in both performance and selected physiological parameters following a Live High-Train Low (LHTL) altitude camp in either normobaric hypoxia (NH) or hypobaric hypoxia (HH) replicating current "real" practices of endurance athletes. Well-trained triathletes were split into two groups (NH, n = 14 and HH, n = 13) and completed an 18-d LHTL camp during which they trained at 1100-1200 m and resided at an altitude of 2250 m (PiO2  = 121.7±1.2 vs. 121.4±0.9 mmHg) under either NH (hypoxic chamber; FiO2 15.8±0.8%) or HH (real altitude; barometric pressure 580±23 mmHg) conditions. Oxygen saturations (SpO2) were recorded continuously daily overnight. PiO2 and training loads were matched daily. Before (Pre-) and 1 day after (Post-) LHTL, blood samples, VO2max, and total haemoglobin mass (Hb(mass)) were measured. A 3-km running test was performed near sea level twice before, and 1, 7, and 21 days following LHTL. During LHTL, hypoxic exposure was lower for the NH group than for the HH group (220 vs. 300 h; P<0.001). Night SpO2 was higher (92.1±0.3 vs. 90.9±0.3%, P<0.001), and breathing frequency was lower in the NH group compared with the HH group (13.9±2.1 vs. 15.5±1.5 breath.min(-1), P<0.05). Immediately following LHTL, similar increases in VO2max (6.1±6.8 vs. 5.2±4.8%) and Hb(mass) (2.6±1.9 vs. 3.4±2.1%) were observed in NH and HH groups, respectively, while 3-km performance was not improved. However, 21 days following the LHTL intervention, 3-km run time was significantly faster in the HH (3.3±3.6%; P<0.05) versus the NH (1.2±2.9%; ns) group. In conclusion, the greater degree of race performance enhancement by day 21 after an 18-d LHTL camp in the HH group was likely induced by a larger hypoxic dose. However, one cannot rule out other factors including differences in sleeping desaturations and breathing patterns, thus suggesting higher hypoxic stimuli in the HH group. PMID:25517507

  13. Studies on organ weights in naproxen treated rats after intermittent exposure to simulated high altitude

    NASA Astrophysics Data System (ADS)

    Saha, R. C.; Biswas, H. M.

    1990-06-01

    Rats were exposed intermittently for 8h per day over 6 days at simulated high altitude of 20 000 feet. One group of altitude-exposed animals was treated with naproxen, a prostaglandin inhibiting drug. Significant reduction in body weight gain was observed in both altitude-exposed and drug-treated altitude-exposed animals compared to the control group. Right and left ventricular weights and weights of the adrenal glands were increased significantly in altitude-exposed and altitude-exposed drug-treated animals. The weight of the spleen was increased significantly in altitude-exposed animals whereas no such increase of splenic weight was observed in drug-treated altitude-exposed group of animals. On the other hand, the weight of the liver was decreased significantly in both cases. In drug-treated altitude-exposed animals, the unaltered splenic weight was thought to be due to inhibition of the erythropoietic activity.

  14. Efforts toward achieving an unmanned, high-altitude LTA platform

    SciTech Connect

    Onda, Masahiko; Ford, M.L.

    1996-10-01

    The modern demands for an unmanned aerospace platform, capable of long-duration stationkeeping at high-altitudes, are well-known. Satellites, balloons, and aircraft have traditionally served in the role of platform, facilitating tasks ranging from telecommunications to deep-space astronomy. However, limitations on the performance and flexibility of these systems, as well as the intrinsically high-cost of satellite construction, operation, and repair, warrants development of a supplemental technology for the platform. Much has been written in the literature on the possible advantages of a lighter-than-air (LTA) platform, if such an LTA could be constructed. Potential applications include remote sensing, environmental monitoring, mobile communications, space and polar observations, cargo delivery, military reconnaissance, and others. At present, conventional LTA`s are not capable of serving in the manner specified. Within this context, a research program known as HALROP (High Altitude Long Range Observational Platform) is currently underway. The goal is to create a stratospheric platform, possibly in the form of a next generation LTA vehicle. The authors present a qualitative review of their efforts, focusing on milestones in the HALROP Program. 12 refs., 6 figs., 2 tabs.

  15. Perseus High Altitude Remotely Piloted Aircraft on Ramp

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Perseus proof-of-concept vehicle waits on Rogers Dry Lake in the pre-dawn darkness before a test flight at the Dryden Flight Research Center, Edwards, California. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation of the Perseus design, which began with the Perseus Proof-Of-Concept aircraft. Perseus was initially developed as part of NASA's Small High-Altitude Science Aircraft (SHASA) program, which later evolved into the

  16. Raised HIF1α during normoxia in high altitude pulmonary edema susceptible non-mountaineers

    PubMed Central

    Soree, Poonam; Gupta, Rajinder K.; Singh, Krishan; Desiraju, Koundinya; Agrawal, Anurag; Vats, Praveen; Bharadwaj, Abhishek; Baburaj, T. P.; Chaudhary, Pooja; Singh, Vijay K.; Verma, Saroj; Bajaj, Amir Chand; Singh, Shashi Bala

    2016-01-01

    High altitude pulmonary edema (HAPE) susceptibility is associated with EGLN1 polymorphisms, we hypothesized that HAPE-susceptible (HAPE-S, had HAPE episode in past) subjects may exhibit abnormal HIF1α levels in normoxic conditions. We measured HIF1α levels in HAPE-S and HAPE resistant (HAPE-R, no HAPE episode) individuals with similar pulmonary functions. Hemodynamic responses were also measured before and after normobaric hypoxia (Fi02 = 0.12 for 30 min duration at sea level) in both groups. . HIF1α was higher in HAPE-S (320.3 ± 267.5 vs 58.75 ± 33.88 pg/ml, P < 0.05) than HAPE-R, at baseline, despite no significant difference in baseline oxygen saturations (97.7 ± 1.7% and 98.8 ± 0.7). As expected, HAPE-S showed an exaggerated increase in pulmonary artery pressure (27.9 ± 6 vs 19.3 ± 3.7 mm Hg, P < 0.05) and a fall in peripheral oxygen saturation (66.9 ± 11.7 vs 78.7 ± 3.8%, P < 0.05), when exposed to hypoxia. HIF1α levels at baseline could accurately classify members of the two groups (AUC = 0.87). In a subset of the groups where hemoglobin fractions were additionally measured to understand the cause of elevated hypoxic response at baseline, two of four HAPE-S subjects showed reduced HbA. In conclusion, HIF 1 α levels during normoxia may represent an important marker for determination of HAPE susceptibility. PMID:27210110

  17. ER-2 High Altitude Solar Cell Calibration Flights

    NASA Technical Reports Server (NTRS)

    Myers, Matthew; Wolford, David; Snyder, David; Piszczor, Michael

    2015-01-01

    Evaluation of space photovoltaics using ground-based simulators requires primary standard cells which have been characterized in a space or near-space environment. Due to the high cost inherent in testing cells in space, most primary standards are tested on high altitude fixed wing aircraft or balloons. The ER-2 test platform is the latest system developed by the Glenn Research Center (GRC) for near-space photovoltaic characterization. This system offers several improvements over GRC's current Learjet platform including higher altitude, larger testing area, onboard spectrometers, and longer flight season. The ER-2 system was developed by GRC in cooperation with NASA's Armstrong Flight Research Center (AFRC) as well as partners at the Naval Research Laboratory and Air Force Research Laboratory. The system was designed and built between June and September of 2014, with the integration and first flights taking place at AFRC's Palmdale facility in October of 2014. Three flights were made testing cells from GRC as well as commercial industry partners. Cell performance data was successfully collected on all three flights as well as solar spectra. The data was processed using a Langley extrapolation method, and performance results showed a less than half a percent variation between flights, and less than a percent variation from GRC's current Learjet test platform.

  18. High altitude Venus haze from Pioneer Venus limb scans

    NASA Astrophysics Data System (ADS)

    Lane, W. A.; Opstbaum, R.

    1983-04-01

    High-resolution limb scans of Venus made with the Orbiter Cloud Photopolarimeter aboard Pioneer Venus have been used to observe the high altitude Venus haze and its variation over almost one half a Venusian year. A model for a spherical atmosphere with tangential viewing geometry was used to analyze the observations and derive the haze properties. Values are found for the particle size and refractive index, particle number density and scale height, and eddy diffusion coefficient. Single scattering computations show good agreement with observed intensities for particles smaller than 0.3 micron radius and refractive index less than 1.7, consistent with, but not limited to, concentrated sulfuric acid. Particle scale height in the 0.5 to 2 mbar pressure regions varies between 1 and 3 km over the season, latitude, and local time ranges of the observations. Detached layers of haze are sometimes present. An average particle scale height of 2.2 km at 84 km altitude yields an eddy diffusion coefficient of 130,000 sq cm/sec.

  19. Three plasma metabolite signatures for diagnosing high altitude pulmonary edema

    NASA Astrophysics Data System (ADS)

    Guo, Li; Tan, Guangguo; Liu, Ping; Li, Huijie; Tang, Lulu; Huang, Lan; Ren, Qian

    2015-10-01

    High-altitude pulmonary edema (HAPE) is a potentially fatal condition, occurring at altitudes greater than 3,000 m and affecting rapidly ascending, non-acclimatized healthy individuals. However, the lack of biomarkers for this disease still constitutes a bottleneck in the clinical diagnosis. Here, ultra-high performance liquid chromatography coupled with Q-TOF mass spectrometry was applied to study plasma metabolite profiling from 57 HAPE and 57 control subjects. 14 differential plasma metabolites responsible for the discrimination between the two groups from discovery set (35 HAPE subjects and 35 healthy controls) were identified. Furthermore, 3 of the 14 metabolites (C8-ceramide, sphingosine and glutamine) were selected as candidate diagnostic biomarkers for HAPE using metabolic pathway impact analysis. The feasibility of using the combination of these three biomarkers for HAPE was evaluated, where the area under the receiver operating characteristic curve (AUC) was 0.981 and 0.942 in the discovery set and the validation set (22 HAPE subjects and 22 healthy controls), respectively. Taken together, these results suggested that this composite plasma metabolite signature may be used in HAPE diagnosis, especially after further investigation and verification with larger samples.

  20. [Should hypertensive patients adapt their antihypertensive drugs during high altitude exposure?].

    PubMed

    Wuerzner, G; Allemann, Y

    2015-09-01

    High altitude exposure during leisure time is becoming more and more frequent. Due to the high prevalence of hypertension in the general population, high altitude exposure in hypertensive patients may not be uncommon. The increase in blood pressure with altitude has been confirmed by ambulatory blood pressure measurement in normotensive as well as in hypertensive patients. Compared to a placebo, most hypertensive drugs keep their blood pressure lowering effect up to a certain altitude. It is recommended that hypertensive patients measure their blood pressure during high altitude, exposure and plan a possible adaptation of treatment with their physician before their sojourn.

  1. High resolution spectroscopy from low altitude satellites. [gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Nakano, G. H.; Imhof, W. L.

    1978-01-01

    The P 78 1 satellite to be placed in a synchronous polar orbit at an altitude of 550-660 km will carry two identical high resolution spectrometers each consisting of a single (approximately 85 cc) intrinsic germanium IGE detector. The payload also includes a pair of phoswitch scintillators, an array of CdTe detectors and several particle detectors, all of which are mounted on the wheel of the satellite. The intrinsic high purity IGE detectors receive cooling from two Stirling cycle refrigerators and facilitate the assembly of large and complex detector arrays planned for the next generation of high sensitivity instruments such as those planned for the gamma ray observatory. The major subsystems of the spectrometer are discussed as well as its capabilities.

  2. Isothermal pumping analysis for high-altitude tethered balloons.

    PubMed

    Kuo, Kirsty A; Hunt, Hugh E M

    2015-06-01

    High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal analysis is used to determine the variation of pressures and velocities along the pipe length. Results show that transport of small quantities of hydrogen to power fuel cells and maintain balloon buoyancy can be achieved at pressures and temperatures that are tolerable in terms of both the pipe strength and the current state of pumping technologies. To avoid solidification, transport of SO2 would require elevated temperatures that cannot be tolerated by the strength fibres in the pipe. While the use of particle-based slurries rather than SO2 for climate engineering can reduce the pipe size significantly, the pumping pressures are close to the maximum bursting pressure of the pipe. PMID:26543573

  3. The High Altitude Student Platform Status and Future Plans

    NASA Astrophysics Data System (ADS)

    Guzik, T. Gregory; Ellison, Steven B.; Gould, Randy; Granger, Douglas; Smith, Douglas; Stewart, Michael; Wefel, John P.

    The High Altitude Student Platform (HASP) is designed to carry multiple student payloads to an altitude of about 36 kilometers with flight durations of 15 to 20 hours using a small volume, zero pressure balloon. To date HASP has had two successful flights (2006, 2007) and is anticipating a third flight this September (2008). Including the upcoming flight, HASP has supported 29 student payloads from 15 institutions across the United States involving about 110 undergraduate and graduate students. By participating in a HASP flight, students gain practical, real-world experience in the design, fabrication, system testing, operation, data analysis and management of an aerospace payload. Such experiences are very difficult to achieve in a normal classroom setting and play an important role in training new aerospace scientists and engineers. During the flights, the HASP control systems have functioned exceptionally well and the modular electronics design has enabled us to maintain flexibility, improve reliability and decrease flight-line support expenses. These capabilities, plus new advances in miniaturized balloon vehicle control systems, may enable the overall weight of HASP to be significantly reduced potentially reducing launch costs and/or improving the student payload to system mass ratio. During the presentation we will discuss the HASP program, previous flights, science results / lessons learned from the student payloads and plans for improving the efficiency of future flights.

  4. Time course of asymptomatic interstitial pulmonary oedema at high altitude.

    PubMed

    Bouzat, Pierre; Walther, Guillaume; Rupp, Thomas; Doucende, Gregory; Payen, Jean-François; Levy, Patrick; Verges, Samuel

    2013-03-01

    The time course of asymptomatic pulmonary oedema during high-altitude exposure and its potential relationship with changes in cardiac function remain to clarify. Eleven volunteers were rapidly exposed to 4350m during a 4-day period. Each subject received clinical examination and thoracic ultrasonography to assess ultrasound lung comets (USLC) on day 1, 2 and 3 after arrival. Echocardiography was performed on day 2 and 4 at 4350m. All subjects had a significant increase in the number of USLC on day 1 (n=8±3), day 2 (n=7±4) and day 3 (n=3±2) compared to sea level (n=1±1) (P<0.01). Although left ventricle diastolic function and systolic tricuspid regurgitation gradient were significantly different at altitude compared to sea level, they did not correlate with the number of USLC (P>0.05). Asymptomatic pulmonary oedema seems to be transiently present in fast-ascending recreational climbers. The lack of correlation between the number of USLC and indices of cardiac changes suggest that non-cardiogenic mechanisms may underlie this transient increase in lung water. PMID:23279868

  5. Radiation Safety Issues in High Altitude Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Cucinotta, Francis A.; Shinn, Judy L.

    1995-01-01

    The development of a global economy makes the outlook for high speed commercial intercontinental flight feasible, and the development of various configurations operating from 20 to 30 km have been proposed. In addition to the still unresolved issues relating to current commercial operations (12-16 km), the higher dose rates associated with the higher operating altitudes makes il imperative that the uncertainties in the atmospheric radiation environment and the associated health risks be re-examined. Atmospheric radiation associated with the galactic cosmic rays forms a background level which may, under some circumstances, exceed newly recommended allowable exposure limits proposed on the basis of recent evaluations of the A -bomb survivor data (due to increased risk coefficients). These larger risk coefficients, within the context of the methodology for estimating exposure limits, are resulting in exceedingly low estimated allowable exposure limits which may impact even present day flight operations and was the reason for the CEC workshop in Luxembourg (1990). At higher operating altitudes, solar particles events can produce exposures many orders of magnitude above background levels and pose significant health risks to the most sensitive individuals (such as during pregnancy). In this case the appropriate quality factors are undefined, and some evidence exists which indicates that the quality factor for stochastic effects is a substantial underestimate.

  6. Isothermal pumping analysis for high-altitude tethered balloons

    PubMed Central

    Kuo, Kirsty A.; Hunt, Hugh E. M.

    2015-01-01

    High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal analysis is used to determine the variation of pressures and velocities along the pipe length. Results show that transport of small quantities of hydrogen to power fuel cells and maintain balloon buoyancy can be achieved at pressures and temperatures that are tolerable in terms of both the pipe strength and the current state of pumping technologies. To avoid solidification, transport of SO2 would require elevated temperatures that cannot be tolerated by the strength fibres in the pipe. While the use of particle-based slurries rather than SO2 for climate engineering can reduce the pipe size significantly, the pumping pressures are close to the maximum bursting pressure of the pipe. PMID:26543573

  7. Scientific verification of High Altitude Water Cherenkov observatory

    NASA Astrophysics Data System (ADS)

    Marinelli, Antonio; Sparks, Kathryne; Alfaro, Ruben; González, María Magdalena; Patricelli, Barbara; Fraija, Nissim

    2014-04-01

    The High Altitude Water Cherenkov (HAWC) observatory is a TeV gamma-ray and cosmic-ray detector currently under construction at an altitude of 4100 m close to volcano Sierra Negra in the state of Puebla, Mexico. The HAWC [1] observatory is an extensive air-shower array composed of 300 optically isolated water Cherenkov detectors (WCDs). Each WCD contains ~200,000 l of filtered water and four upward-facing photomultiplier tubes. In Fall 2014, when the HAWC observatory will reach an area of 22,000 m2, the sensitivity will be 15 times higher than its predecessor Milagro [2]. Since September 2012, more than 30 WCDs have been instrumented and taking data. This first commissioning phase has been crucial for the verification of the data acquisition and event reconstruction algorithms. Moreover, with the increasing number of instrumented WCDs, it is important to verify the data taken with different configuration geometries. In this work we present a comparison between Monte Carlo simulation and data recorded by the experiment during 24 h of live time between 14 and 15 April of 2013 when 29 WCDs were active.

  8. Development and testing of airfoils for high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Drela, Mark (Principal Investigator)

    1996-01-01

    Specific tasks included airfoil design; study of airfoil constraints on pullout maneuver; selection of tail airfoils; examination of wing twist; test section instrumentation and layout; and integrated airfoil/heat-exchanger tests. In the course of designing the airfoil, specifically for the APEX test vehicle, extensive studies were made over the Mach and Reynolds number ranges of interest. It is intended to be representative of airfoils required for lightweight aircraft operating at extreme altitudes, which is the primary research objective of the APEX program. Also considered were thickness, pitching moment, and off-design behavior. The maximum ceiling parameter M(exp 2)C(sub L) value achievable by the Apex-16 airfoil was found to be a strong constraint on the pullout maneuver. The NACA 1410 and 2410 airfoils (inverted) were identified as good candidates for the tail, with predictable behavior at low Reynolds numbers and good tolerance to flap deflections. With regards to wing twist, it was decided that a simple flat wing was a reasonable compromise. The test section instrumentation consisted of surface pressure taps, wake rakes, surface-mounted microphones, and skin-friction gauges. Also, a modest wind tunnel test was performed for an integrated airfoil/heat-exchanger configuration, which is currently on Aurora's 'Theseus' aircraft. Although not directly related to the APEX tests, the aerodynamics or heat exchangers has been identified as a crucial aspect of designing high-altitude aircraft and hence is relevant to the ERAST program.

  9. Long-term genetic stability and a high-altitude East Asian origin for the peoples of the high valleys of the Himalayan arc

    PubMed Central

    Jeong, Choongwon; Ozga, Andrew T.; Witonsky, David B.; Malmström, Helena; Edlund, Hanna; Hofman, Courtney A.; Hagan, Richard W.; Jakobsson, Mattias; Lewis, Cecil M.; Aldenderfer, Mark S.; Di Rienzo, Anna

    2016-01-01

    The high-altitude transverse valleys [>3,000 m above sea level (masl)] of the Himalayan arc from Arunachal Pradesh to Ladahk were among the last habitable places permanently colonized by prehistoric humans due to the challenges of resource scarcity, cold stress, and hypoxia. The modern populations of these valleys, who share cultural and linguistic affinities with peoples found today on the Tibetan plateau, are commonly assumed to be the descendants of the earliest inhabitants of the Himalayan arc. However, this assumption has been challenged by archaeological and osteological evidence suggesting that these valleys may have been originally populated from areas other than the Tibetan plateau, including those at low elevation. To investigate the peopling and early population history of this dynamic high-altitude contact zone, we sequenced the genomes (0.04×–7.25×, mean 2.16×) and mitochondrial genomes (20.8×–1,311.0×, mean 482.1×) of eight individuals dating to three periods with distinct material culture in the Annapurna Conservation Area (ACA) of Nepal, spanning 3,150–1,250 y before present (yBP). We demonstrate that the region is characterized by long-term stability of the population genetic make-up despite marked changes in material culture. The ancient genomes, uniparental haplotypes, and high-altitude adaptive alleles suggest a high-altitude East Asian origin for prehistoric Himalayan populations. PMID:27325755

  10. An Investigation into the Nature of High Altitude Cosmic Radiation in the Stratosphere

    ERIC Educational Resources Information Center

    Bancroft, Samuel; Bancroft, Ben; Greenwood, Jake

    2014-01-01

    An experiment was carried out to investigate the changes in ionizing cosmic radiation as a function of altitude. This was carried out using a Geiger-Müller tube on-board a high altitude balloon, which rose to an altitude of 31 685 m. The gathered data show that the Geiger-Müller tube count readings increased to a maximum at an altitude of about 24…

  11. Thermoelectric Energy Conversion Technology for High-Altitude Airships

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Elliott, James R.; King, Glen C.; Park, Yeonjoon; Kim, Jae-Woo; Chu, Sang-Hyon

    2011-01-01

    The High Altitude Airship (HAA) has various application potential and mission scenarios that require onboard energy harvesting and power distribution systems. The power technology for HAA maneuverability and mission-oriented applications must come from its surroundings, e.g. solar power. The energy harvesting system considered for HAA is based on the advanced thermoelectric (ATE) materials being developed at NASA Langley Research Center. The materials selected for ATE are silicon germanium (SiGe) and bismuth telluride (Bi2Te3), in multiple layers. The layered structure of the advanced TE materials is specifically engineered to provide maximum efficiency for the corresponding range of operational temperatures. For three layers of the advanced TE materials that operate at high, medium, and low temperatures, correspondingly in a tandem mode, the cascaded efficiency is estimated to be greater than 60 percent.

  12. Radiation Physics for Space and High Altitude Air Travel

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Wilson, J. W.; Goldhagen, P.; Saganti, P.; Shavers, M. R.; McKay, Gordon A. (Technical Monitor)

    2000-01-01

    Galactic cosmic rays (GCR) are of extra-solar origin consisting of high-energy hydrogen, helium, and heavy ions. The GCR are modified by physical processes as they traverse through the solar system, spacecraft shielding, atmospheres, and tissues producing copious amounts of secondary radiation including fragmentation products, neutrons, mesons, and muons. We discuss physical models and measurements relevant for estimating biological risks in space and high-altitude air travel. Ambient and internal spacecraft computational models for the International Space Station and a Mars mission are discussed. Risk assessment is traditionally based on linear addition of components. We discuss alternative models that include stochastic treatments of columnar damage by heavy ion tracks and multi-cellular damage following nuclear fragmentation in tissue.

  13. Electric Power System for High Altitude UAV Technology Survey

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Electric powertrain technologies with application to high altitude Unmanned Aerial Vehicles (UAV) are assessed. One hundred twenty five solar electric UAV configurations and missions were simulated. Synergistic design opportunities were investigated with the premise that specific benefits may be realized, for example, if a single component can serve multiple functions, such as a battery being used for energy storage as well as for a structural component of the aircraft. For each UAV mission simulation, the airframe structure, powertrain configuration (type of solar cells, energy storage options) and performance baseline (1997 or 2001) were specified. It has been found that the use of the high efficiency (multijunction) solar cells or the use of the synergistic amorphous silicon solar cell configuration yields aircraft that can accomplish the majority of the missions of interest for any latitude between 0 deg and 55 deg, hence, a single versatile aircraft can be constructed and implemented to accomplish these missions.

  14. Aeroelastic considerations for continuous patrol/high altitude surveillance platforms

    NASA Technical Reports Server (NTRS)

    Turner, C. D.; Rocketts, R. H.

    1983-01-01

    For the last several years, an investigation has been conducted regarding the feasibility of unmanned, airborne, High-Altitude Powered Platforms (HAPP), and High Surveillance Platforms for Over-the-Horizon Targeting (HI-SPOT). These airborne platforms have been proposed as a means of achieving a continuous regional communication-relay or for continuous regional surveillance for use in agricultural research or military applications, i.e., fleet support. These platforms would offer improvements over existing orbiting satellites. These improvements are related to better resolution and increased mission flexibility. The required mission endurance up to six months, would be obtained through the use of either solar power, a cryogenically fueled engine, or microwave-power. Attention is given to airborne platform configuration, structure, structural and aerodynamic modeling, modal analysis, and flutter analysis.

  15. Centurion solar-powered high-altitude aircraft in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Since 1980 AeroVironment, Inc. (founded in 1971 by the ultra-light airplane innovator--Dr. Paul MacCready) has been experimenting with solar-powered aircraft, often in conjunction with the NASA Dryden Flight Research Center, Edwards, California. Thus far, AeroVironment, now headquartered in Monrovia, California, has achieved several altitude records with its Solar Challenger, Pathfinder, and Pathfinder-Plus aircraft. It expects to exceed these records with the newer and larger solar-powered Centurion and its successors the Centelios and Helios vehicles, in the NASA Environmental Research Aircraft and Sensor Technology (ERAST) program. The Centurion is a lightweight, solar-powered, remotely piloted flying wing aircraft that is demonstrating the technology of applying solar power for long-duration, high-altitude flight. It is considered to be a prototype technology demonstrator for a future fleet of solar-powered aircraft that could stay airborne for weeks or months on scientific sampling and imaging missions or while serving as telecommunications relay platforms. Although it shares many of the design concepts of the Pathfinder, the Centurion has a wingspan of 206 feet, more than twice the 98-foot span of the original Pathfinder and 70-percent longer than the Pathfinder-Plus' 121-foot span. At the same time, Centurion maintains the 8-foot chord (front to rear distance) of the Pathfinder wing, giving the wing an aspect ratio (length-to-chord) of 26 to 1. Other visible changes from its predecessor include a modified wing airfoil designed for flight at extreme altitude and four underwing pods to support its landing gear and electronic systems (compared with two such pods on the Pathfinder). The flexible wing is primarily fabricated from carbon fiber, graphite epoxy composites, and kevlar. It is built in five sections, a 44-foot-long center section and middle and outer sections just over 40 feet long. All five sections have an identical thickness--12 percent of the chord

  16. Role of the RhoA/ROCK pathway in high-altitude associated neonatal pulmonary hypertension in lambs.

    PubMed

    Lopez, Nandy C; Ebensperger, German; Herrera, Emilio A; Reyes, Roberto V; Calaf, Gloria; Cabello, Gertrudis; Moraga, Fernando A; Beñaldo, Felipe A; Diaz, Marcela; Parer, Julian T; Llanos, Anibal J

    2016-06-01

    Exposure to high-altitude chronic hypoxia during pregnancy may cause pulmonary hypertension in neonates, as a result of vasoconstriction and vascular remodeling. We hypothesized that susceptibility to pulmonary hypertension, due to an augmented expression and activity of the RhoA/Rho-kinase (ROCK) pathway in these neonates, can be reduced by daily administration of fasudil, a ROCK inhibitor. We studied 10 highland newborn lambs with conception, gestation, and birth at 3,600 m in Putre, Chile. Five highland controls (HLC) were compared with 5 highland lambs treated with fasudil (HL-FAS; 3 mg·kg(-1)·day(-1) iv for 10 days). Ten lowland controls were studied in Lluta (50 m; LLC). During the 10 days of fasudil daily administration, the drug decreased pulmonary arterial pressure (PAP) and resistance (PVR), basally and during a superimposed episode of acute hypoxia. HL-FAS small pulmonary arteries showed diminished muscular area and a reduced contractile response to the thromboxane analog U46619 compared with HLC. Hypoxia, but not fasudil, changed the protein expression pattern of the RhoA/ROCKII pathway. Moreover, HL-FAS lungs expressed less pMYPT1(T850) and pMYPT1T(696) than HLC, with a potential increase of the myosin light chain phosphatase activity. Finally, hypoxia induced RhoA, ROCKII, and PKG mRNA expression in PASMCs of HLC, but fasudil reduced them (HL-FAS) similarly to LLC. We conclude that fasudil decreases the function of the RhoA/ROCK pathway, reducing the PAP and PVR in chronically hypoxic highland neonatal lambs. The inhibition of ROCKs by fasudil may offer a possible therapeutic tool for the pulmonary hypertension of the neonates.

  17. High-altitude Cusp Precipitation for Different IMF Orientations

    NASA Astrophysics Data System (ADS)

    Nemecek, Z.; Safrankova, J.; Simunek, J.

    2005-12-01

    Reconnection is the most important process in the magnetospheric physics. Dayside reconnection of interplanetary and terrestrial magnetic fields supplies the magnetosphere with a huge amount of the solar wind plasma that is then released due to reconnection occurring in the tail. In spite of its principal importance, reconnection is still understood insufficiently. The main problem is probably connected with the fact that both MHD and kinetic processes are equally important for its initialization and further development. Experimental investigations are difficult because reconnection spots are limited in space and time and a probability that a spacecraft is located in appropriate time at a right position is very low. However, all possible places where magnetopause reconnection can occur are magnetically connected to the cusp and thus the plasma proceeding along reconnected magnetic field lines brings information on reconnection. As observed by the various spacecraft at both low and high altitudes, a cusp precipitation is often characterized by ion energy dispersion. During southward IMF, ion energy falls with increasing magnetic latitudes due to the convection electric field operating as a velocity filter on particles from the injection point to the observation point. The high-energy ions rapidly reach lower latitudes and the lower-energy ions appear later at higher latitudes. By contrast, if reconnection takes place in the tail lobes, the high-energy ions quickly reach higher latitudes, whereas the low-energy ions are convected to lower latitudes and thus the ion energy-latitude dispersion signifies the boundary of open and closed magnetic field lines. We are presenting case studies of crossings of the cusp region at high altitudes which reveal that both spatial and temporal changes should be taken into account for an explanation of the observed features. Moreover, our study shows that the cusp can be supplied from two simultaneously operating reconnection sites

  18. Critique of the equivalent air altitude model.

    PubMed

    Conkin, Johnny; Wessel, James H

    2008-10-01

    The adverse effects of hypoxic hypoxia include acute mountain sickness (AMS), high altitude pulmonary edema, and high altitude cerebral edema. It has long been assumed that those manifestations are directly related to reduction in the inspired partial pressure of oxygen (P(I)O2). This assumption underlies the equivalent air altitude (EAA) model, which holds that combinations of barometric pressure (P(B)) and inspired fraction of O2 (F(I)O2) that produce the same P(I)O2 will result in identical physiological responses. However, a growing body of evidence seems to indicate that different combinations of P(B) and P(I)O2 may produce different responses to the same P(I)O2. To investigate this question with respect to AMS, we conducted a search of the literature using the terms hypobaric hypoxia, normobaric hypoxia, and hypobaric normoxia. The results suggest that the EAA model provides only an approximate description of isohypoxia, and that P(B) has an independent effect on hypoxia and AMS. A historical report from 1956 and 15 reports from 1983 to 2005 compare the same hypoxic P(I)O2 at different P(B) with respect to the development of hypoxia and AMS. These data provide evidence for an independent effect of P(B) on hypoxia and AMS, and thereby invalidate EAA as an ideal model of isohypoxia. Refinement of the EAA model is needed, in particular for applications to high altitude where supplemental O2 is inadequate to prevent hypoxic hypoxia. Adjustment through probabilistic statistical modeling to match the current limited experimental observations is one approach to a better isohypoxic model. PMID:18856188

  19. Risk assessment of high altitude free flight commercial aircraft operations

    SciTech Connect

    Kimura, C.Y.; Sandquist, G.M.; Slaughter, D.M.; Sanzo, D.L.

    1998-04-23

    A quantitative model is under development to assess the safety and efficiency of commercial aircraft operations under the Free Flight Program proposed for air traffic control for the US National Airspace System. The major objective of the Free Flight Program is to accommodate the dramatic growth anticipated in air traffic in the US. However, the potential impacts upon aircraft safety from implementing the Program have not been fully explored and evaluated. The model is directed at assessing aircraft operations at high altitude over the continental US airspace since this action is the initial step for Free Flight. Sequential steps with analysis, assessment, evaluation, and iteration will be required to satisfactorily accomplish the complete transition of US commercial aircraft traffic operations.

  20. The High-Altitude Water Cherenkov Observatory: First Light

    NASA Astrophysics Data System (ADS)

    Weisgarber, Thomas

    2013-04-01

    The High-Altitude Water Cherenkov (HAWC) Observatory is under construction at Sierra Negra in the state of Puebla in Mexico. Operation began in September 2012, with the first 30 out of the final 300 water Cherenkov detectors deployed and in data acquisition. The HAWC Observatory is designed to record particle air showers from gamma rays and cosmic rays with TeV energies. Though the detector is only 10% complete, HAWC is already the world's largest water Cherenkov detector in the TeV band. In this presentation, I will summarize the performance of the detector to date and discuss preliminary observations of cosmic-ray and gamma-ray sources. I will also describe deployment plans for the remainder of the detector and outline prospects for TeV observations in the coming year.

  1. A nominal set of high-altitude EMP environments

    SciTech Connect

    Longmire, C.L.; Hamilton, R.M.; Hahn, J.M.

    1987-02-01

    This report presents high-altitude EMP (HEMP) environments calculated by the CHAP code for a nominal large yield burst at 400 km over the central US. Nominal, unclassified weapon output parameters were used, along with unclassified EMP theory and calculational techniques. While the resulting environments do not represent upper bounds, they should be useful in developing understanding of the effect of HEMP on electrical and electronic systems. The calculated environments illustrate the wide variability of the HEMP from a single burst, depending on ground range and azimuth from ground zero. Analytic fits to the HEMP fields are provided to facilitate coupling calculations. The CHAP results are justified by a detailed examination of Compton currents, air conductivities, and the resulting fields. It is shown that both HEMP theory and the calculations conserve energy scrupulously.

  2. Recent gamma background measurements at high mountain altitude.

    PubMed

    Mishev, A L; Hristova, E

    2012-11-01

    Results from recent measurements of radiation gamma background at high mountain altitude, namely at Basic Environmental Observatory Moussala (42.11 N, 23.35 E, 2925 m a.s.l.) are reported. The measurements are fulfilled with several devices, namely IGS-421 gamma probe and MDU Liulin. A comparative analysis with previous measurements performed with SBN-90 SAPHYMO NaI(Tl) gamma probe is carried out. A temperature effect during winter period of SAPHYMO probe is observed. In addition the measurements are compared with CaSO(4):Dy TLD. The obtained results are widely discussed. A numerical model for galactic cosmic ray contribution to the dose rate in air is presented. The model is based on a full Monte Carlo simulation of cosmic ray induced cascade in the atmosphere. The simulation is carried out with CORSIKA 6.52 code using FLUKA 2006b and QGSJET II hadron interaction models. PMID:22659148

  3. New horizons for the national high-altitude photography program

    USGS Publications Warehouse

    Bermel, Peter F.

    1983-01-01

    The National High-Altitude Photography Program (NHAP) is a multi-Federal agency activity to acquire uniform imagery for the establishment of a national high-altitude photographic data base. Federal agencies participating in NHAP have pooled their resources and consolidated photographic requirements in a systematic 6-year effort that will minimize duplication of photographic programs, reduce overall Federal expenditures for aerial photography, and provide imagery for a wide range of public and private users, The U.S. Geological Survey has the lead coordination role and shares, with the other participating agencies, the responsibility for funding the acquisition of photography. Since the inception of NHAP in 1980, black-and-white and color infrared stereoscopic imagery has been acquired for about 50% of the 3,000,000 square miles in the conterminous United States. An additional 40% of the 48-State area is under contract to provide aerial survey firms, and the sixth and final contract to achieve complete once-over coverage will be awarded early in 1985. Extensive use has been made of the newly established data base for mapping, landform studies, land use planning, natural resource inventory, evaluation and management, engineering, and education. In anticipation of the completion of once-over coverage, the participating agencies have begun studies to define the requirements for a maintenance program which would provide cyclic coverage of the conterminous United States and imagery for specific agency needs. Although continued funding at the same level is not assured, under consideration are requirements for new cameras, films, and other remote sensors, photographic parameters, and extension of program coverage to Alaska, Hawaii, and outlying areas. In addition, new applications of the data base to prepare cartographic map and data products are being investigated. It is becoming increasingly clear that some major decision needs to be made soon if a NHAP II is to begin in

  4. A High-Altitude Search for Vulcanoids: Progress Report

    NASA Astrophysics Data System (ADS)

    Durda, D. D.; Stern, S. A.; Terrell, D. C.; Weidenschilling, S. J.

    2002-09-01

    We are conducting a unique, high-altitude observing campaign to search for vulcanoids, a population of small, asteroid-like bodies hypothesized to reside in the dynamically stable region interior to Mercury's orbit (i.e., orbits with aphelia <0.21 AU). This airborne search campaign utilizes our versatile and highly capable SWUIS-A (Southwest Universal Imaging System - Airborne) instrument flown with the flight astronomer (SAS and DDD) to an altitude of 49,000 MSL aboard NASA F/A-18B aircraft in order to obtain darker twilight conditions for near-Sun observing than are possible from the ground. The first observing run was successfully completed at NASA's Dryden Flight Research Center during the March/April 2002 vernal equinox observing opportunity. On each of the three evening flights we recorded image data covering 250 square degrees of sky centered on the ecliptic from solar elongations of 6-18 deg. Initial reduction of portions of the Mar/Apr 2002 data set demonstrates that we are reliably detecting objects to magnitude V = 9.5 at 15 degrees solar elongation. This is at least a magnitude fainter than the best previous ground-based searches and comparable to the faintest stars visible in our space-based SOHO LASCO C3 coronagraph vulcanoids search. The SWUIS-A instrument itself is capable of imaging objects as faint as magnitude V = 13, corresponding to vulcanoids less than 10 km across, with a sufficiently dark sky background; we are working to mitigate sky background brightness to reach these deeper magnitude limits for a second F/A-18B observing run during the September 2002 autumnal equinox observing opportunity. We thank NASA research pilots Rick Searfoss, Dana Purifoy, and Craig Bomben. This research is supported by the NASA Planetary Astronomy program, NASA's Dryden Flight Research Center, and the National Geographic Society.

  5. AltitudeOmics: enhanced cerebrovascular reactivity and ventilatory response to CO2 with high-altitude acclimatization and reexposure.

    PubMed

    Fan, Jui-Lin; Subudhi, Andrew W; Evero, Oghenero; Bourdillon, Nicolas; Kayser, Bengt; Lovering, Andrew T; Roach, Robert C

    2014-04-01

    The present study is the first to examine the effect of high-altitude acclimatization and reexposure on the responses of cerebral blood flow and ventilation to CO2. We also compared the steady-state estimates of these parameters during acclimatization with the modified rebreathing method. We assessed changes in steady-state responses of middle cerebral artery velocity (MCAv), cerebrovascular conductance index (CVCi), and ventilation (V(E)) to varied levels of CO2 in 21 lowlanders (9 women; 21 ± 1 years of age) at sea level (SL), during initial exposure to 5,260 m (ALT1), after 16 days of acclimatization (ALT16), and upon reexposure to altitude following either 7 (POST7) or 21 days (POST21) at low altitude (1,525 m). In the nonacclimatized state (ALT1), MCAv and V(E) responses to CO2 were elevated compared with those at SL (by 79 ± 75% and 14.8 ± 12.3 l/min, respectively; P = 0.004 and P = 0.011). Acclimatization at ALT16 further elevated both MCAv and Ve responses to CO2 compared with ALT1 (by 89 ± 70% and 48.3 ± 32.0 l/min, respectively; P < 0.001). The acclimatization gained for V(E) responses to CO2 at ALT16 was retained by 38% upon reexposure to altitude at POST7 (P = 0.004 vs. ALT1), whereas no retention was observed for the MCAv responses (P > 0.05). We found good agreement between steady-state and modified rebreathing estimates of MCAv and V(E) responses to CO2 across all three time points (P < 0.001, pooled data). Regardless of the method of assessment, altitude acclimatization elevates both the cerebrovascular and ventilatory responsiveness to CO2. Our data further demonstrate that this enhanced ventilatory CO2 response is partly retained after 7 days at low altitude.

  6. Differences in Hematological Traits between High- and Low-Altitude Lizards (Genus Phrynocephalus)

    PubMed Central

    Lu, Songsong; Xin, Ying; Tang, Xiaolong; Yue, Feng; Wang, Huihui; Bai, Yucheng; Niu, Yonggang; Chen, Qiang

    2015-01-01

    Phrynocephalus erythrurus (Lacertilia: Agamidae) is considered to be the highest living reptile in the world (about 4500-5000 m above sea level), whereas Phrynocephalus przewalskii inhabits low altitudes (about 1000-1500 m above sea level). Here, we report the differences in hematological traits between these two different Phrynocephalus species. Compared with P. przewalskii, the results indicated that P. erythrurus own higher oxygen carrying capacity by increasing red blood cell count (RBC), hemoglobin concentration ([Hb]) and hematocrit (Hct) and these elevations could promote oxygen carrying capacity without disadvantage of high viscosity. The lower partial pressure of oxygen in arterial blood (PaO2) of P. erythrurus did not cause the secondary alkalosis, which may be attributed to an efficient pulmonary system for oxygen (O2) loading. The elevated blood-O2 affinity in P. erythrurus may be achieved by increasing intrinsic O2 affinity of isoHbs and balancing the independent effects of potential heterotropic ligands. We detected one α-globin gene and three β-globin genes with 1 and 33 amino acid substitutions between these two species, respectively. Molecular dynamics simulation results showed that amino acids substitutions in β-globin chains could lead to the elimination of hydrogen bonds in T-state Hb models of P. erythrurus. Based on the present data, we suggest that P. erythrurus have evolved an efficient oxygen transport system under the unremitting hypobaric hypoxia. PMID:25955247

  7. [Phospholipids and structural modification of tissues and cell membranes for adaptation in high altitude mountains].

    PubMed

    Iakovlev, V M; Vishnevskiĭ, A A; Shanazarov, A S

    2012-01-01

    The nature of the impact of physical factors of high altitudes (3200 m) on the lipids of tissues and membranes of animals was researched. It was established that the adaptation process in Wistar rats was followed by peroxide degradation and subsequent modification of the phospholipids' structure of tissues and microsomal membranes. Adaptive phospholipids reconstruction takes place in microsomal membranes in the tissues of the lungs, brain, liver and skeletal muscles. Together with this, the amount of phosphatidylinositol and phosphatidic acid accumulates, indicating that the hydrolysis of phosphatidylinositol-4, 5 biphosphate to diacylglycerol and secondary messenger--inositol triphosphate, occurs. A decrease in temperature adaptation (+10 degrees C) leads to a more noticeable shift in peroxide oxidation of lipids, phospholipid structure in the tissues and membranes rather than adaptation in thermoneutral conditions (+30 degrees C). Modification of lipid composition of tissues and cell membranes in the highlands obviously increases the adaptive capabilities of cells of the whole body: physical performance and resistance to hypoxia increases in animals. PMID:22586936

  8. Differences in Hematological Traits between High- and Low-Altitude Lizards (Genus Phrynocephalus).

    PubMed

    Lu, Songsong; Xin, Ying; Tang, Xiaolong; Yue, Feng; Wang, Huihui; Bai, Yucheng; Niu, Yonggang; Chen, Qiang

    2015-01-01

    Phrynocephalus erythrurus (Lacertilia: Agamidae) is considered to be the highest living reptile in the world (about 4500-5000 m above sea level), whereas Phrynocephalus przewalskii inhabits low altitudes (about 1000-1500 m above sea level). Here, we report the differences in hematological traits between these two different Phrynocephalus species. Compared with P. przewalskii, the results indicated that P. erythrurus own higher oxygen carrying capacity by increasing red blood cell count (RBC), hemoglobin concentration ([Hb]) and hematocrit (Hct) and these elevations could promote oxygen carrying capacity without disadvantage of high viscosity. The lower partial pressure of oxygen in arterial blood (PaO2) of P. erythrurus did not cause the secondary alkalosis, which may be attributed to an efficient pulmonary system for oxygen (O2) loading. The elevated blood-O2 affinity in P. erythrurus may be achieved by increasing intrinsic O2 affinity of isoHbs and balancing the independent effects of potential heterotropic ligands. We detected one α-globin gene and three β-globin genes with 1 and 33 amino acid substitutions between these two species, respectively. Molecular dynamics simulation results showed that amino acids substitutions in β-globin chains could lead to the elimination of hydrogen bonds in T-state Hb models of P. erythrurus. Based on the present data, we suggest that P. erythrurus have evolved an efficient oxygen transport system under the unremitting hypobaric hypoxia.

  9. KGF-2 targets alveolar epithelia and capillary endothelia to reduce high altitude pulmonary oedema in rats

    PubMed Central

    She, Jun; Goolaerts, Arnaud; Shen, Jun; Bi, Jing; Tong, Lin; Gao, Lei; Song, Yuanlin; Bai, Chunxue

    2012-01-01

    High altitude pulmonary oedema (HAPE) severely affects non-acclimatized individuals and is characterized by alveolar flooding with protein- rich oedema as a consequence of blood-gas barrier disruption. Limited choice for prophylactic treatment warrants effective therapy against HAPE. Keratinocyte growth factor-2 (KGF-2) has shown efficiency in preventing alveolar epithelial cell DNA damages in vitro. In the current study, the effects of KGF-2 intratracheal instillation on mortality, lung liquid balance and lung histology were evaluated in our previously developed rat model of HAPE. We found that pre-treatment with KGF-2 (5 mg/kg) significantly decreased mortality, improved oxygenation and reduced lung wet-to-dry weight ratio by preventing alveolar-capillary barrier disruption demonstrated by histological examination and increasing alveolar fluid clearance up to 150%. In addition, KGF-2 significantly inhibited decrease of transendothelial permeability after exposure to hypoxia, accompanied by a 10-fold increase of Akt activity and inhibited apoptosis in human pulmonary microvascular endothelial cells, demonstrating attenuated endothelial apoptosis might contribute to reduction of endothelial permeability. These results showed the efficacy of KGF-2 on inhibition of endothelial cell apoptosis, preservation of alveolar-capillary barrier integrity and promotion of pulmonary oedema absorption in HAPE. Thus, KGF-2 may represent a potential drug candidate for the prevention of HAPE. PMID:22568566

  10. [Phospholipids and structural modification of tissues and cell membranes for adaptation in high altitude mountains].

    PubMed

    Iakovlev, V M; Vishnevskiĭ, A A; Shanazarov, A S

    2012-01-01

    The nature of the impact of physical factors of high altitudes (3200 m) on the lipids of tissues and membranes of animals was researched. It was established that the adaptation process in Wistar rats was followed by peroxide degradation and subsequent modification of the phospholipids' structure of tissues and microsomal membranes. Adaptive phospholipids reconstruction takes place in microsomal membranes in the tissues of the lungs, brain, liver and skeletal muscles. Together with this, the amount of phosphatidylinositol and phosphatidic acid accumulates, indicating that the hydrolysis of phosphatidylinositol-4, 5 biphosphate to diacylglycerol and secondary messenger--inositol triphosphate, occurs. A decrease in temperature adaptation (+10 degrees C) leads to a more noticeable shift in peroxide oxidation of lipids, phospholipid structure in the tissues and membranes rather than adaptation in thermoneutral conditions (+30 degrees C). Modification of lipid composition of tissues and cell membranes in the highlands obviously increases the adaptive capabilities of cells of the whole body: physical performance and resistance to hypoxia increases in animals.

  11. Vitamin D, Iron Metabolism, and Diet in Alpinists During a 2-Week High-Altitude Climb.

    PubMed

    Kasprzak, Zbigniew; Śliwicka, Ewa; Hennig, Karol; Pilaczyńska-Szcześniak, Łucja; Huta-Osiecka, Anna; Nowak, Alicja

    2015-09-01

    A defensive mechanism against hypobaric hypoxia at high altitude is erythropoesis. Some authors point to the contribution of vitamin D to the regulation of this process. The aim of the present study was to assess the 25-hydroxycholecalciferol (25(OH)D) level and its associations with iron metabolic and inflammatory indices in participants of a 2-week mountaineering expedition. The study sample included 9 alpinists practicing recreational mountain climbing. Every 2 or 3 days they set up a different base between 3200 and 3616 m with the intention of climbing 4000 m peaks in the Mont Blanc massif. Before their departure for the mountains and 2 days after returning to the sea level anthropometric parameters, hematological parameters, serum levels of 25(OH)D and iron metabolic indices were measured in all the participants. The composition of the participants' diet was also evaluated. The comparative analysis showed a significant decrease in body mass, BMI values, total iron, and 25(OH)D concentrations (p<0.05). Also significant increases in unsaturated iron-binding capacity, hematocrit, and C-reactive protein concentrations (p<0.05) were found. It can be concluded that the 2-week climbing expedition contributed to the reduction of 25(OH)D levels and these changes were associated with modulation of immune processes. Moreover, the climbers' diet requires some serious modifications. PMID:26125641

  12. Prevalence of hypertension at high altitude: cross-sectional survey in Ladakh, Northern India 2007–2011

    PubMed Central

    Norboo, Tsering; Stobdan, Tsering; Tsering, Norboo; Angchuk, Norboo; Tsering, Phunsog; Ahmed, Iqbal; Chorol, Tsewang; Kumar Sharma, Vijay; Reddy, Prasanna; Singh, Shashi Bala; Kimura, Yumi; Sakamoto, Ryota; Fukutomi, Eriko; Ishikawa, Motonao; Suwa, Kuniaki; Kosaka, Yasuyuki; Nose, Mitsuhiro; Yamaguchi, Takayoshi; Tsukihara, Toshihiro; Matsubayashi, Kozo; Otsuka, Kuniaki; Okumiya, Kiyohito

    2015-01-01

    Objective Prevalence of hypertension was examined in a widely dispersed (45 110 km2) representative group of Ladakhi in Northern India. The influence of hypoxic environment of wide-ranged altitude (2600–4900 m) and lifestyle change on hypertension was studied. Methods 2800 participants (age 20–94 years) were enrolled. Systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure of ≥90 mm Hg and/or taking current anti-hypertensive medicine was defined as hypertension. Height and weight for body mass index and SpO2 were examined. The rural population comprised six subdivisions with a distinct altitude, dietary and occupational pattern. Participants in the urban area of Leh consist of two groups, that is, migrants settled in Leh from the Changthang nomadic area, and dwellers born in Leh. The prevalence of hypertension in the two groups was compared with that in the farmers and nomads in rural areas. The effects of ageing, hypoxia, dwelling at high altitude, obesity, modernised occupation, dwelling in an urban area, and rural-to-urban migration to hypertension were analysed by multiple logistic regression. Results The prevalence of hypertension was 37.0% in all participants and highest in migrants settled in Leh (48.3%), followed by dwellers born in Leh town (41.1%) compared with those in rural areas (33.5). The prevalence of hypertension in nomads (all: 27.7%, Tibetan/Ladakhi: 19.7/31.9%)) living at higher altitude (4000–4900 m) was relatively low. The associated factors with hypertension were ageing, overweight, dwelling at higher altitude, engagement in modernised sedentary occupations, dwelling in urban areas, and rural-to-urban migration. The effects of lifestyle change and dwelling at high altitude were independently associated with hypertension by multivariate analysis adjusted with confounding factors. Conclusions Socioeconomic and cultural factors play a big role with the effect of high altitude itself on high prevalence of

  13. From Low Altitude to High Altitude: Assimilating SAMPEX Data in Global Radiation Belt Models by Quantifying Precipitation and Loss

    NASA Astrophysics Data System (ADS)

    Tu, W.; Reeves, G. D.; Cunningham, G.; Selesnick, R. S.; Li, X.; Looper, M. D.

    2012-12-01

    Since its launch in 1992, SAMPEX has been continuously providing measurements of radiation belt electrons at low altitude, which are not only ideal for the direct quantification of the electron precipitation loss in the radiation belt, but also provide data coverage in a critical region for global radiation belt data assimilation models. However, quantitatively combining high-altitude and low-earth-orbit (LEO) measurements on the same L-shell is challenging because LEO measurements typically contain a dynamic mixture of trapped and precipitating populations. Specifically, the electrons measured by SAMPEX can be distinguished as trapped, quasi-trapped (in the drift loss cone), and precipitating (in the bounce loss cone). To simulate the low-altitude electron distribution observed by SAMPEX/PET, a drift-diffusion model has been developed that includes the effects of azimuthal drift and pitch angle diffusion. The simulation provides direct quantification of the rates and variations of electron loss to the atmosphere, a direct input to our Dynamic Radiation Environment Assimilation Model (DREAM) as the electron loss lifetimes. The current DREAM uses data assimilation to combine a 1D radial diffusion model with observational data of radiation belt electrons. In order to implement the mixed electron measurements from SAMPEX into DREAM, we need to map the SAMPEX data from low altitude to high altitudes. To perform the mapping, we will first examine the well-known 'global coherence' of radiation belt electrons by comparing SAMPEX electron fluxes with the energetic electron data from LANL GEO and GPS spacecraft. If the correlation is good, we can directly map the SAMPEX fluxes to high altitudes based on the global coherence; if not, we will use the derived pitch angle distribution from the drift-diffusion model to map up the field and test the mapping by comparing to the high-altitude flux measurements. Then the globally mapped electron fluxes can be assimilated into DREAM

  14. Impaired acclimatization to chronic hypoxia in adult male and female rats following neonatal hypoxia.

    PubMed

    Lumbroso, Delphine; Joseph, Vincent

    2009-08-01

    We tested the hypothesis that neonatal exposure to hypoxia alters acclimatization to chronic hypoxia later in life. Rat pups were exposed to normobaric hypoxia (12% O(2); nHx group) in a sealed chamber, or to normoxia (21% O(2); nNx group) from the day before birth to postnatal day 10. The animals were then raised in normal conditions until reaching 12 wk of age. At this age, we assessed ventilatory and hematological acclimatization to chronic hypoxia by exposing male and female nHx and nNx rats for 2 wk to 10% O(2). Minute ventilation, metabolic rate, hypoxic ventilatory response, hematocrit, and hemoglobin levels were measured both before and after acclimatization. We also quantified right ventricular hypertrophy as an index of pulmonary hypertension both before and after acclimatization. There was a significant effect of neonatal hypoxia that decreases ventilatory response (relative to metabolic rate, VE/VCO(2)) to acute hypoxia before acclimatization in males but not in females. nHx rats had an impaired acclimatization to chronic hypoxia characterized by altered respiratory pattern and elevated hematocrit and hemoglobin levels after acclimatization, in both males and females. Right ventricular hypertrophy was present before and after acclimatization in nHx rats, indicating that neonatal hypoxia results in pulmonary hypertension in adults. We conclude that neonatal hypoxia impairs acclimatization to chronic hypoxia in adults and may be a factor contributing to the establishment of chronic mountain sickness in humans living at high altitude.

  15. The HAMMER: High altitude multiple mission environmental researcher

    NASA Technical Reports Server (NTRS)

    Hayashi, Darren; Zylla, Cara; Amaro, Ernesto; Colin, Phil; Klause, Thomas; Lopez, Bernardo; Williamson, Danna

    1991-01-01

    At the equator, the ozone layer ranges from 65,000 to 130,000+ feet which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to satisfy four mission profiles. Mission one is a polar mission which ranges from Chile to the South Pole and back to Chile, a total range of 6000 n. mi. at 100,000 feet with a 2500 lb. payload. The second mission is also a polar mission with a decreased altitude of 70,000 feet and an increased payload of 4000 lb. For the third mission, the aircraft will take-off at NASA Ames, cruise at 100,000 feet carrying a 2500 lb. payload, and land in Puerto Montt, Chile. The final mission requires the aircraft to take-off at NASA Ames, cruise at 100,000 feet with a 1000 lb. payload, make an excursion to 120,000 feet, and land at Howard AFB, Panama. All three missions require that a subsonic Mach number is maintained due to constraints imposed by the air sampling equipment. The aircraft need not be manned for all four missions. Three aircraft configurations were determined to be the most suitable for meeting the above requirements. The performance of each configuration is analyzed to investigate the feasibility of the project requirements. In the event that a requirement can not be obtained within the given constraints, recommendations for proposal modifications are given.

  16. Deducing high-altitude precipitation from glacier mass balance measurements

    NASA Astrophysics Data System (ADS)

    Giesen, Rianne H.; Immerzeel, Walter W.; Wanders, Niko

    2016-04-01

    The spatial distribution of precipitation in mountainous terrain is generally not well known due to underrepresentation of gauge observations at higher elevations. Precipitation tends to increase with elevation, but since observations are mainly performed in the valleys, the vertical precipitation gradient cannot be deduced from these measurements. Furthermore, the spatial resolution of gridded meteorological data is often too coarse to resolve individual mountain chains. Still, a reliable estimate of high-elevation precipitation is required for many hydrological applications. We present a method to determine the vertical precipitation gradient in mountainous terrain, making use of glacier mass balance observations. These measurements have the advantage that they provide a basin-wide precipitation estimate at high elevations. The precipitation gradient is adjusted until the solid precipitation over the glacier area combined with the calculated melt gives the measured annual glacier mass balance. Results for the glacierized regions in Central Europe and Scandinavia reveal spatially coherent patterns, with predominantly positive precipitation gradients ranging from -4 to +28 % (100 m)‑1. In some regions, precipitation amounts at high elevations are up to four times as large as in the valleys. A comparison of the modelled winter precipitation with observed snow accumulation on glaciers shows a good agreement. Precipitation measured at the few high-altitude meteorological stations is generally lower than our estimate, which may result from precipitation undercatch. Our findings will improve the precipitation forcing for glacier modelling and hydrological studies in mountainous terrain.

  17. Medical continuing education: reform of teaching methods about high altitude disease in China.

    PubMed

    Luo, Yongjun; Zhou, Qiquan; Huang, Jianjun; Luo, Rong; Yang, Xiaohong; Gao, Yuqi

    2013-06-01

    The purpose of high altitude continuing medical education is to adapt knowledge and skills for practical application on the plateau. Most trainees have experience with academic education and grassroots work experience on the plateau, so they want knowledge about new advances in the pathogenesis, diagnosis, and treatment of high altitude disease. As such, traditional classroom teaching methods are not useful to them. Training objects, content, and methods should attempt to conduct a variety of teaching practices. Through continuing medical education on high altitude disease, the authors seek to change the traditional teaching model away from a single classroom and traditional written examinations to expand trainees' abilities. These innovative methods of training can improve both the quality of teaching and students' abilities to prevent and treat acute mountain sickness, high altitude pulmonary edema, high altitude cerebral edema, and chronic mountain sickness to increase the quality of high altitude medical care.

  18. Latest news from the High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    González Muñoz, A.; HAWC Collaboration

    2016-07-01

    The High Altitude Water Cherenkov Observatory is an air shower detector designed to study very-high-energy gamma rays (∼ 100 GeV to ∼ 100 TeV). It is located in the Pico de Orizaba National Park, Mexico, at an elevation of 4100 m. HAWC started operations since August 2013 with 111 tanks and in April of 2015 the 300 tanks array was completed. HAWC's unique capabilities, with a field of view of ∼ 2 sr and a high duty cycle of 5%, allow it to survey 2/3 of the sky every day. These features makes HAWC an excellent instrument for searching new TeV sources and for the detection of transient events, like gamma-ray bursts. Moreover, HAWC provides almost continuous monitoring of already known sources with variable gamma-ray fluxes in most of the northern and part of the southern sky. These observations will bring new information about the acceleration processes that take place in astrophysical environments. In this contribution, some of the latest scientific results of the observatory will be presented.

  19. Latest news from the High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    González Muñoz, A.; HAWC Collaboration

    2016-07-01

    The High Altitude Water Cherenkov Observatory is an air shower detector designed to study very-high-energy gamma rays (˜ 100 GeV to ˜ 100 TeV). It is located in the Pico de Orizaba National Park, Mexico, at an elevation of 4100 m. HAWC started operations since August 2013 with 111 tanks and in April of 2015 the 300 tanks array was completed. HAWC's unique capabilities, with a field of view of ˜ 2 sr and a high duty cycle of 5%, allow it to survey 2/3 of the sky every day. These features makes HAWC an excellent instrument for searching new TeV sources and for the detection of transient events, like gamma-ray bursts. Moreover, HAWC provides almost continuous monitoring of already known sources with variable gamma-ray fluxes in most of the northern and part of the southern sky. These observations will bring new information about the acceleration processes that take place in astrophysical environments. In this contribution, some of the latest scientific results of the observatory will be presented.

  20. Risk Stratification for Athletes and Adventurers in High-Altitude Environments: Recommendations for Preparticipation Evaluation.

    PubMed

    Campbell, Aaron D; McIntosh, Scott E; Nyberg, Andy; Powell, Amy P; Schoene, Robert B; Hackett, Peter

    2015-12-01

    High-altitude athletes and adventurers face a number of environmental and medical risks. Clinicians often advise participants or guiding agencies before or during these experiences. Preparticipation evaluation (PPE) has the potential to reduce risk of high-altitude illnesses in athletes and adventurers. Specific conditions susceptible to high-altitude exacerbation also important to evaluate include cardiovascular and lung diseases. Recommendations by which to counsel individuals before participation in altitude sports and adventures are few and of limited focus. We reviewed the literature, collected expert opinion, and augmented principles of a traditional sport PPE to accommodate the high-altitude wilderness athlete/adventurer. We present our findings with specific recommendations on risk stratification during a PPE for the high-altitude athlete/adventurer.

  1. Efficient utilization of aerobic metabolism helps Tibetan locusts conquer hypoxia

    PubMed Central

    2013-01-01

    Background Responses to hypoxia have been investigated in many species; however, comparative studies between conspecific geographical populations at different altitudes are rare, especially for invertebrates. The migratory locust, Locusta migratoria, is widely distributed around the world, including on the high-altitude Tibetan Plateau (TP) and the low-altitude North China Plain (NP). TP locusts have inhabited Tibetan Plateau for over 34,000 years and thus probably have evolved superior capacity to cope with hypoxia. Results Here we compared the hypoxic responses of TP and NP locusts from morphological, behavioral, and physiological perspectives. We found that TP locusts were more tolerant of extreme hypoxia than NP locusts. To evaluate why TP locusts respond to extreme hypoxia differently from NP locusts, we subjected them to extreme hypoxia and compared their transcriptional responses. We found that the aerobic metabolism was less affected in TP locusts than in NP locusts. RNAi disruption of PDHE1β, an entry gene from glycolysis to TCA cycle, increased the ratio of stupor in TP locusts and decreased the ATP content of TP locusts in hypoxia, confirming that aerobic metabolism is critical for TP locusts to maintain activity in hypoxia. Conclusions Our results indicate that TP and NP locusts have undergone divergence in hypoxia tolerance. These findings also indicate that insects can adapt to hypoxic pressure by modulating basic metabolic processes. PMID:24047108

  2. Health, Safety and Performance in High Altitude Observatories: A Sustainable Approach

    NASA Astrophysics Data System (ADS)

    Böcker, Michael; Vogt, Joachim; Christ, Oliver; Müller-Leonhardt, Alice

    2009-09-01

    The research project “Optimising Performance, Health and Safety in High Altitude Observatories” was initiated by ESO to establish an approach to promote the well-being of staff working at its high altitude observatories, and in particular at the Antiplano de Chajnantor. A survey by a questionnaire given to both workers and visitors was employed to assess the effects of working conditions at high altitude. Earlier articles have outlined the project and reported early results. The final results and conclusions are presented, together with a concept for sustainable development to improve the performance, health and safety at high altitude employing Critical Incident Stress Management.

  3. Left ventricular adaptation to high altitude: speckle tracking echocardiography in lowlanders, healthy highlanders and highlanders with chronic mountain sickness.

    PubMed

    Dedobbeleer, Chantal; Hadefi, Alia; Pichon, Aurelien; Villafuerte, Francisco; Naeije, Robert; Unger, Philippe

    2015-04-01

    Hypoxic exposure depresses myocardial contractility in vitro, but has been associated with indices of increased cardiac performance in intact animals and in humans, possibly related to sympathetic nervous system activation. We explored left ventricular (LV) function using speckle tracking echocardiography and sympathetic tone by spectral analysis of heart rate variability (HRV) in recently acclimatized lowlanders versus adapted or maladapted highlanders at high altitude. Twenty-six recently acclimatized lowlanders, 14 healthy highlanders and 12 highlanders with chronic mountain sickness (CMS) were studied. Control measurements at sea level were also obtained in the lowlanders. Altitude exposure in the lowlanders was associated with slightly increased blood pressure, decreased LV volumes and decreased longitudinal strain with a trend to increased prevalence of post-systolic shortening (p = 0.06), whereas the low frequency/high frequency (LF/HF) ratio increased (1.62 ± 0.81 vs. 5.08 ± 4.13, p < 0.05) indicating sympathetic activation. Highlanders had a similarly raised LF/HF ratio, but no alteration in LV deformation. Highlanders with CMS had no change in LV deformation, no significant increase in LF/HF, but decreased global HRV still suggestive of increased sympathetic tone, and lower mitral E/A ratio compared to healthy highlanders. Short-term altitude exposure in lowlanders alters indices of LV systolic function and increases sympathetic nervous system tone. Life-long altitude exposure in highlanders is associated with similar sympathetic hyperactivity, but preserved parameters of LV function, whereas diastolic function may be altered in those with CMS. Altered LV systolic function in recently acclimatized lowlanders may be explained by combined effects of hypoxia and changes in loading conditions.

  4. Time lapse photography of clouds from high altitude balloons.

    PubMed

    Vonnegut, B

    1970-08-01

    Time lapse pictures of clouds taken by cameras flown at altitudes of 30 km on balloons provide valuable insights into the convection and electrification of cloud systems. Simple camera arrangements for taking such pictures are described.

  5. When is O+ Observed in the High Altitude Polar Cap?

    NASA Technical Reports Server (NTRS)

    Elliott, H. A.; Comfort, R. H.; Craven, P. D.; Chandler, M. O.; Moore, T. E.

    2000-01-01

    Solar wind and IMF properties are correlated with the properties of O+ and H+ in the polar cap at altitudes greater than 5.5 Re geocentric using the Thermal Ion Dynamics Experiment (TIDE) on the Polar satellite. O+ is of primary interest in this study because the fraction of O+ present in the magnetosphere is commonly used as a measure of the ionospheric contribution to the magnetosphere. O+ is observed to be most abundant at lower latitudes when the solar wind speed is low and across most of the polar cap at high solar winds speeds and Kp. As the solar wind dynamic pressures increases more O+ is present in the polar cap. The O+ density is also shown to be more highly correlated with the solar wind dynamic pressure when IMF Bz is positive. H+ was not as well correlated with solar wind and IMF parameters although some correlation with IMF By is observed. H+ is more plentiful when IMF By is negative than when it is positive. In this data set H+ is very dominate so that if this plasma makes it to the plasma sheet its contribution to the plasma sheet would have a very low O+ to H+ ratio.

  6. Propulsion System for Very High Altitude Subsonic Unmanned Aircraft

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Mockler, Ted; Maldonado, Jaime; Harp, James L., Jr.; King, Joseph F.; Schmitz, Paul C.

    1998-01-01

    This paper explains why a spark ignited gasoline engine, intake pressurized with three cascaded stages of turbocharging, was selected to power NASA's contemplated next generation of high altitude atmospheric science aircraft. Beginning with the most urgent science needs (the atmospheric sampling mission) and tracing through the mission requirements which dictate the unique flight regime in which this aircraft has to operate (subsonic flight at greater then 80 kft) we briefly explore the physical problems and constraints, the available technology options and the cost drivers associated with developing a viable propulsion system for this highly specialized aircraft. The paper presents the two available options (the turbojet and the turbocharged spark ignited engine) which are discussed and compared in the context of the flight regime. We then show how the unique nature of the sampling mission, coupled with the economic considerations pursuant to aero engine development, point to the spark ignited engine as the only cost effective solution available. Surprisingly, this solution compares favorably with the turbojet in the flight regime of interest. Finally, some remarks are made about NASA's present state of development, and future plans to flight demonstrate the three stage turbocharged powerplant.

  7. Raman spectroscopy of hot desert, high altitude epilithic lichens.

    PubMed

    Villar, Susana E Jorge; Edwards, Howell G M; Seaward, Mark R D

    2005-05-01

    Twenty-three highly-coloured lichen specimens belonging to the genera Candelariella, Aspicilia and Xanthoria from high altitude sites in the Atacama Desert, Chile, 2300-4500 metres, have been analysed non-destructively by Raman spectroscopy. The vibrational band assignments in the spectra of the specimens, which were still attached to their limestone or sandstone substrata, were accomplished by comparison with the chemical compositions obtained from wet chemical extraction methods. Carotenoids and chlorophyll were found in all specimens as major components and the characteristic spectral signatures of calcium oxalate monohydrate (whewellite) and dihydrate (weddellite) could be identified; chemical signatures were found for these materials even in lichen thalli growing on the non-calcareous substrata, indicating probably that the calcium was provided here from wind- or rain-borne sources. The Raman spectral biomarkers for a variety of protective biomolecules and accessory pigments such as usnic acid, calycin, pulvinic acid dilactone and rhizocarpic acid have been identified in the lichens, in broad agreement with the chemical extraction profiles. The present study indicates that some form of non-destructive taxonomic identification based on Raman spectroscopy was also possible.

  8. Physiological responses and evaluation of effects of BMI, smoking and drinking in high altitude acclimatization: a cohort study in Chinese Han young males.

    PubMed

    Peng, Qian-Qian; Basang, Zhuoma; Cui, Chao-Ying; Li, Lei; Qian, Ji; Gesang, Quzhen; Yang, La; La, Zong; De, Yang; Dawa, Puchi; Qu, Ni; Suo, Qu; Dan, Zhen; Xiao, Duoji; Wang, Xiao-Feng; Jin, Li

    2013-01-01

    High altitude acclimatization is a series of physiological responses taking places when subjects go to altitude. Many factors could influence these processes, such as altitude, ascending speed and individual characteristics. In this study, based on a repeated measurement design of three sequential measurements at baseline, acute phase and chronic phase, we evaluated the effect of BMI, smoking and drinking on a number of physiological responses in high altitude acclimatization by using mixed model and partial least square path model on a sample of 755 Han Chinese young males. We found that subjects with higher BMI responses were reluctant to hypoxia. The effect of smoking was not significant at acute phase. But at chronic phase, red blood cell volume increased less while respiratory function increased more for smoking subjects compared with nonsmokers. For drinking subjects, red blood cell volume increased less than nondrinkers at both acute and chronic phases, while blood pressures increased more than nondrinkers at acute phase and respiratory function, red blood cell volume and oxygen saturation increased more than nondrinkers at chronic phase. The heavy and long-term effect of smoking, drinking and other factors in high altitude acclimatization needed to be further studied.

  9. Incidence of high altitude illnesses among unacclimatized persons who acutely ascended to Tibet.

    PubMed

    Ren, Yusheng; Fu, Zhongming; Shen, Weimin; Jiang, Ping; He, Yanlin; Peng, Shaojun; Wu, Zonggui; Cui, Bo

    2010-01-01

    High altitude illnesses pose health threats to unwary travelers after their acute ascent to high altitude locations. The incidence of high altitude illnesses among unacclimatized persons who acutely ascend to Tibet has not been previously reported. In the present study, we surveyed the incidence of high altitude illness among 3628 unacclimatized persons who had no previous high altitude experience and who traveled to Tibet by air to an altitude of 3600 m. These subjects were asked to answer questions in a written questionnaire about symptoms associated with high altitude illnesses that occurred within 2 weeks of their first arrival, their severity, and possible contributing factors. Physical examination and appropriate laboratory tests were also performed for hospitalized subjects. We found that 2063 respondents had mild acute mountain sickness with an incidence of 57.2%, and 249 (12.07%) of them were hospitalized for treatment. The incidence of high altitude pulmonary edema was 1.9%, while no case of high altitude cerebral edema was found. Additionally, there was no report of death. Psychological stresses and excessive physical exertions possibly contributed to the onset of HAPE. Acute mountain sickness is common among unacclimatized persons after their acute ascent to Tibet. The incidence of HAPE and HACE, however, is very low among them. PMID:20367487

  10. Radar-anomalous, high-altitude features on Venus

    NASA Technical Reports Server (NTRS)

    Muhleman, Duane O.; Butler, Bryan J.

    1992-01-01

    Over nearly all of the surface of Venus the reflectivity and emissivity at centimeter wavelengths are about 0.15 and 0.85 respectively. These values are consistent with moderately dense soils and rock populations, but the mean reflectivity is about a factor of 2 greater than that for the Moon and other terrestrial planets. Pettingill and Ford, using Pioneer Venus reflectivities and emissivities, found a number of anomalous features on Venus that showed much higher reflectivities and much lower emissivities with both values approaching 0.5. These include Maxwell Montes, a number of high regions in Aphrodite Terra and Beta Regio, and several isolated mountain peaks. Most of the features are at altitudes above the mean radius by 2 to 3 km or more. However, such features have been found in the Magellan data at low altitudes and the anomalies do not exist on all high structures, Maat Mons being the most outstanding example. A number of papers have been written that attempt to explain the phenomena in terms of the geochemistry balance of weathering effects on likely surface minerals. The geochemists have shown that the fundamentally basaltic surface would be stable at the temperatures and pressures of the mean radius in the form of magnetite, but would evolve to pyrite and/or pyrrhotite in the presence of sulfur-bearing compounds such as SO2. Pyrite will be stable at altitudes above 4 or 5 km on Venus. Although the geochemical arguments are rather compelling, it is vitally important to rationally look at other explanations for radar and radio emission measurements such as that presented by Tryka and Muhleman. The radar reflectivity values are retrieved from the raw Magellan backscatter measurements by fitting the Hagfors' radar scattering model in which a surface roughness parameters and a normal incidence electrical reflectivity are estimated. The assumptions of the theory behind the mo