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https://www.readbyqxmd.com/read/28533889/effects-of-low-dose-acetazolamide-on-exercise-performance-in-simulated-altitude
#1
Ernst Elisabeth, Gatterer Hannes, Burtscher Johannes, Faulhaber Martin, Pocecco Elena, Burtscher Martin
Preventive effects of acetazolamide (ACZ) on acute mountain sickness (AMS) are well established but effects on exercise performance at high altitude or in hypoxia have been less considered and are still inconsistent. We hypothesized that low-dose ACZ would not impair exercise performance at simulated high altitude. Thus, the aim of this study was to evaluate the interaction between low-dose ACZ and exercise performance in normobaric hypoxia. Sixteen subjects (8 males and 8 females) were randomly assigned either to receive low-dose ACZ (3×125 mg in 36 hours) or placebo...
2017: International Journal of Physiology, Pathophysiology and Pharmacology
https://www.readbyqxmd.com/read/28533386/metabolic-basis-to-sherpa-altitude-adaptation
#2
James A Horscroft, Aleksandra O Kotwica, Verena Laner, James A West, Philip J Hennis, Denny Z H Levett, David J Howard, Bernadette O Fernandez, Sarah L Burgess, Zsuzsanna Ament, Edward T Gilbert-Kawai, André Vercueil, Blaine D Landis, Kay Mitchell, Monty G Mythen, Cristina Branco, Randall S Johnson, Martin Feelisch, Hugh E Montgomery, Julian L Griffin, Michael P W Grocott, Erich Gnaiger, Daniel S Martin, Andrew J Murray
The Himalayan Sherpas, a human population of Tibetan descent, are highly adapted to life in the hypobaric hypoxia of high altitude. Mechanisms involving enhanced tissue oxygen delivery in comparison to Lowlander populations have been postulated to play a role in such adaptation. Whether differences in tissue oxygen utilization (i.e., metabolic adaptation) underpin this adaptation is not known, however. We sought to address this issue, applying parallel molecular, biochemical, physiological, and genetic approaches to the study of Sherpas and native Lowlanders, studied before and during exposure to hypobaric hypoxia on a gradual ascent to Mount Everest Base Camp (5,300 m)...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28532572/rates-and-causes-of-accidents-for-general-aviation-aircraft-operating-in-a-mountainous-and-high-elevation-terrain-environment
#3
Marisa Aguiar, Alan Stolzer, Douglas D Boyd
BACKGROUND: Flying over mountainous and/or high elevation terrain is challenging due to rapidly changeable visibility, gusty/rotor winds and downdrafts and the necessity of terrain avoidance. Herein, general aviation accident rates and mishap cause/factors were determined (2001-2014) for a geographical region characterized by such terrain. METHODS: Accidents in single piston engine-powered aircraft for states west of the US continental divide characterized by mountainous terrain and/or high elevation (MEHET) were identified from the NTSB database...
May 19, 2017: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/28530483/carotidynia-in-high-altitude-travelers
#4
Andrea Parra, Tamuru Okada, Peter H Lin
Background Carotidynia is characterized by focal pain and tenderness of the carotid artery without associated hemodynamic or structural abnormalities. Carotid artery pathology has also been known to occur in high altitude due to aberrant baroreceptor response in the carotid bulb. Case Presentation We herein report two cases of high altitude-related idiopathic carotidynia. The first patient was a geologist who performed oil reserve survey in the Alaska Mountain, while the second patient was hiking in a mountain trail in Peru...
January 1, 2017: Vascular
https://www.readbyqxmd.com/read/28530447/middle-ear-function-and-pathophysiology-in-andean-children-living-at-high-altitudes
#5
S Allen Counter, Leo H Buchanan, Fernando Ortega, Anthony B Jacobs, Göran Laurell
Counter, S. Allen, Leo H. Buchanan, Fernando Ortega, Anthony B. Jacobs, and Göran Laurell. Middle ear function and pathophysiology in Andean children living at high altitudes. High Alt Med Biol 00:000-000, 2017.-The extent of altitude-related middle ear disorders in children native to high altitudes is unclear. This study examined middle ear pathophysiology in two groups of children living in high-altitude Ecuadorian Andean communities by investigating middle ear pressure (MEP), tympanic membrane compliance (TMC), and ear canal volume (ECV) using tympanometry, and by otological examination...
May 22, 2017: High Altitude Medicine & Biology
https://www.readbyqxmd.com/read/28529459/cold-inducible-rna-binding-protein-is-involved-in-chronic-hypoxia-induced-neuron-apoptosis-by-down-regulating-hif-1%C3%AE-expression-and-regulated-by-microrna-23a
#6
Xiaoming Chen, Xinqin Liu, Bin Li, Qian Zhang, Jiye Wang, Wenbin Zhang, Wenjing Luo, Jingyuan Chen
Background: Neuron apoptosis mediated by hypoxia inducible factor 1α (HIF-1α) in hippocampus is one of the most important factors accounting for the chronic hypobaric hypoxia induced cognitive impairment. As a neuroprotective molecule that is up-regulated in response to various environmental stress, CIRBP was reported to crosstalk with HIF-1α under cellular stress. However, its function under chronic hypobaric hypoxia remains unknown. Objective: In this study, we tried to identify the role of CIRBP in HIF-1α mediated neuron apoptosis under chronic hypobaric hypoxia and find a possible method to maintain its potential neuroprotective in long-term high altitude environmental exposure...
2017: International Journal of Biological Sciences
https://www.readbyqxmd.com/read/28527334/photo-protective-mechanisms-in-reed-canary-grass-to-alleviate-photo-inhibition-of-psii-on-the-qinghai-tibet-plateau
#7
Chao Zhang, Da-Wei Zhang, Yan-Ni Sun, Muhammad Arfan, Da-Xu Li, Jia-Jun Yan, Ming-Hong You, Shi-Qie Bai, Hong-Hui Lin
Due to its characteristic of high biomass yield potential, there is considerable interest in cultivating Phalaris arundinacea L. cv. 'chuancaoyin No.3' (reed canary grass) on the Qinghai-Tibet Plateau where there is an abundance of alpine steppe meadow and a potential large market for animal husbandry. In this study, we 1) investigate whether reed canary grass exhibits superior productive capacity to Elymus nutans 'Aba' (E. nutans), ordinary common pasture, during the long warm days of summer at high-altitude; and 2) compare the cold tolerance between reed canary grass and E...
May 4, 2017: Journal of Plant Physiology
https://www.readbyqxmd.com/read/28526872/seasonal-soil-microbial-responses-are-limited-to-changes-in-functionality-at-two-alpine-forest-sites-differing-in-altitude-and-vegetation
#8
José A Siles, Rosa Margesin
The study of soil microbial responses to environmental changes is useful to improve simulation models and mitigation strategies for climate change. We here investigated two Alpine forest sites (deciduous forest vs. coniferous forest) situated at different altitudes (altitudinal effect) in spring and autumn (seasonal effect) regarding: (i) bacterial and fungal abundances (qPCR); (ii) diversity and structure of bacterial and fungal communities (amplicon sequencing); and (iii) diversity and composition of microbial functional gene community (Geochip 5...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28522921/thin-air-resulting-in-high-pressure-mountain-sickness-and-hypoxia-induced-pulmonary-hypertension
#9
REVIEW
Jan Grimminger, Manuel Richter, Khodr Tello, Natascha Sommer, Henning Gall, Hossein Ardeschir Ghofrani
With rising altitude the partial pressure of oxygen falls. This phenomenon leads to hypobaric hypoxia at high altitude. Since more than 140 million people permanently live at heights above 2500 m and more than 35 million travel to these heights each year, understanding the mechanisms resulting in acute or chronic maladaptation of the human body to these circumstances is crucial. This review summarizes current knowledge of the body's acute response to these circumstances, possible complications and their treatment, and health care issues resulting from long-term exposure to high altitude...
2017: Canadian Respiratory Journal: Journal of the Canadian Thoracic Society
https://www.readbyqxmd.com/read/28522767/individual-hemoglobin-mass-response-to-normobaric-and-hypobaric-live-high-train-low-a-one-year-crossover-study
#10
Anna Hauser, Severin Troesch, Jonas J Saugy, Laurent Schmitt, Roberto Cejuela-Anta, Raphael Faiss, Thomas Steiner, Neil Robinson, Grégoire P Millet, Jon Peter Wehrlin
PURPOSE: To compare individual hemoglobin mass (Hbmass) changes following a live high-train low (LHTL) altitude training camp under either normobaric hypoxia (NH) or hypobaric hypoxia (HH) conditions in endurance athletes. METHODS: In a crossover design with a one-year washout, 15 male triathletes randomly performed two 18-d LHTL training camps in either HH or NH. All athletes slept at 2250 m and trained at altitudes < 1200 m. Hbmass was measured in duplicate with the optimized carbon monoxide rebreathing method before (pre-) and immediately after (post-) each 18 d training camp...
May 18, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28518046/epidemiologic-survey-of-japanese-encephalitis-virus-infection-tibet-china-2015
#11
Hui Zhang, Mujeeb Ur Rehman, Kun Li, Houqiang Luo, Yanfang Lan, Fazul Nabi, Lihong Zhang, Muhammad Kashif Iqbal, Suolangsi Zhu, Muhammad Tariq Javed, Yangzom Chamba, Jia Kui Li
We investigated Japanese encephalitis virus (JEV) prevalence in high-altitude regions of Tibet, China, by using standard assays to test mosquitoes, pigs, and humans. Results confirmed that JEV has spread to these areas. Disease prevention and control strategies should be used along with surveillance to limit spread of JEV in high-altitude regions of Tibet.
June 2017: Emerging Infectious Diseases
https://www.readbyqxmd.com/read/28516029/the-power-of-vertical-geolocation-of-atmospheric-profiles-from-gnss-radio-occultation
#12
Barbara Scherllin-Pirscher, Andrea K Steiner, Gottfried Kirchengast, Marc Schwärz, Stephen S Leroy
High-resolution measurements from Global Navigation Satellite System (GNSS) radio occultation (RO) provide atmospheric profiles with independent information on altitude and pressure. This unique property is of crucial advantage when analyzing atmospheric characteristics that require joint knowledge of altitude and pressure or other thermodynamic atmospheric variables. Here we introduce and demonstrate the utility of this independent information from RO and discuss the computation, uncertainty, and use of RO atmospheric profiles on isohypsic coordinates-mean sea level altitude and geopotential height-as well as on thermodynamic coordinates (pressure and potential temperature)...
February 16, 2017: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28514266/pulmonary-vascular-function-and-aerobic-exercise-capacityat-moderate-altitude
#13
Vitalie Faoro, Gael Deboeck, Marco Vicenzi, Anne-Fleur Gaston, Bamodi Simaga, Grégory Doucende, Ilona Hapkova, Emma Roca, Enric Subirats, Fabienne Durand, Robert Naeije
PURPOSE: There has been suggestion that a greater "pulmonary vascular reserve" defined by a low pulmonary vascular resistance (PVR) and a high lung diffusing capacity (DL) allows for a superior aerobic exercise capacity. How pulmonary vascular reserve might affect exercise capacity at moderate altitude is not known. METHODS: Thirty-eight healthy subjects underwent an exercise stress echocardiography of the pulmonary circulation, combined with measurements of DL for nitric oxide (NO) and carbon monoxide (CO) and a cardio-pulmonary exercise test at sea level and at the altitude of 2250m...
May 17, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28512324/global-gene-expression-analysis-provides-insight-into-local-adaptation-to-geothermal-streams-in-tadpoles-of-the-andean-toad-rhinella-spinulosa
#14
Luis Pastenes, Camilo Valdivieso, Alex Di Genova, Dante Travisany, Andrew Hart, Martín Montecino, Ariel Orellana, Mauricio Gonzalez, Rodrigo A Gutiérrez, Miguel L Allende, Alejandro Maass, Marco A Méndez
The anuran Rhinella spinulosa is distributed along the Andes Range at altitudes that undergo wide daily and seasonal variation in temperature. One of the populations inhabits geothermal streams, a stable environment that influences life history traits such as the timing of metamorphosis. To investigate whether this population has undergone local adaptation to this unique habitat, we carried out transcriptome analyses in animals from two localities in two developmental stages (prometamorphic and metamorphic) and exposed them to two temperatures (20 and 25 °C)...
May 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28509579/findings-of-cognitive-impairment-at-high-altitude-relationships-to-acetazolamide-use-and-acute-mountain-sickness
#15
Lara Phillips, Buddha Basnyat, Yuchiao Chang, Erik R Swenson, N Stuart Harris
Phillips, Lara, Buddha Basnyat, Yuchiao Chang, Erik R. Swenson, and N. Stuart Harris. Findings of cognitive impairment at high altitude: relationships to acetazolamide use and acute mountain sickness. High Alt Med Biol. 00:000-000, 2017.-Objective: Acute mountain sickness (AMS) is defined by patient-reported symptoms using the Lake Louise Score (LLS), which provides limited insight into any possible underlying central nervous system (CNS) dysfunction. Some evidence suggests AMS might coexist with altered neural functioning...
May 16, 2017: High Altitude Medicine & Biology
https://www.readbyqxmd.com/read/28507362/visual-outcome-of-retinal-vein-occlusion-in-patients-residing-at-high-altitude
#16
Ahsan Mukhtar, Muhammad Saim Khan, Asad Habib, Mazhar Ishaq, Omer Farooq
OBJECTIVE: To study visual outcome in patients of high altitude retinopathy presenting with retinal venous occlusion. METHODS: The randomised clinical trial study was conducted at the Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan, from January 2013 to December 2015, and comprised eyes of lowlanders. Patients staying at high altitude (>8,000 feet above sea level) as part of their service duty and presented with retinal venous occlusive disease were included...
May 2017: JPMA. the Journal of the Pakistan Medical Association
https://www.readbyqxmd.com/read/28506793/frequency-and-risk-factors-analysis-of-escherichia-coli-o157-h7-in-bali-cattle
#17
I Wayan Suardana, Dyah Ayu Widiasih, Widagdo Sri Nugroho, Michael Haryadi Wibowo, I Nyoman Suyasa
Cattle are known as the main reservoir of zoonotic agents verocytotoxin-producing Escherichia coli. These bacteria are usually isolated from calves with diarrhea and/or mucus and blood. Tolerance of these agents to the environmental conditions will strengthen of their transmission among livestock. A total of 238 cattle fecal samples from four sub-districts in Badung, Bali were used in this study. Epidemiological data observed include cattle age, sex, cattle rearing system, the source of drinking water, weather, altitude, and type of cage floor, the cleanliness of cage floor, the slope of cage floor, and the level of cattle cleanliness...
May 12, 2017: Acta Tropica
https://www.readbyqxmd.com/read/28506292/normobaric-hypoxia-overnight-impairs-cognitive-reaction-time
#18
Stephan Pramsohler, Stefan Wimmer, Martin Kopp, Hannes Gatterer, Martin Faulhaber, Martin Burtscher, Nikolaus Cristoph Netzer
BACKGROUND: Impaired reaction time in patients suffering from hypoxia during sleep, caused by sleep breathing disorders, is a well-described phenomenon. High altitude sleep is known to induce periodic breathing with central apneas and oxygen desaturations, even in perfectly healthy subjects. However, deficits in reaction time in mountaineers or workers after just some nights of hypoxia exposure are not sufficiently explored. Therefore, we aimed to investigate the impact of sleep in a normobaric hypoxic environment on reaction time divided by its cognitive and motoric components...
May 15, 2017: BMC Neuroscience
https://www.readbyqxmd.com/read/28504494/staphylococcus-aureus-nasal-carriage-and-its-antibiotic-resistance-profiles-in-children-in-high-altitude-areas-of-southwestern-china
#19
Zongrong Gong, Min Shu, Qing Xia, Shan Tan, Wei Zhou, Yu Zhu, Chaomin Wan
BACKGROUND/AIM: To describe the epidemiological profile of nasal carriage of Staphylococcus aureus (S. aureus) strains, its antibiotic resistance and mecA and Panton Valentine leukocidin (PVL) genes presence, in school children residing in high altitude areas of Southwestern China. METHODS: The cross sectional study screened nasal swabs taken from students for S.aureus. PCR was performed to identify mecA and PVL genes. RESULTS: Of the total 314 children 5...
June 1, 2017: Archivos Argentinos de Pediatría
https://www.readbyqxmd.com/read/28501324/using-a-new-plateau-hyperbaric-chamber-to-alleviate-high-altitude-hypoxia-rabbit-and-human-studies
#20
Liang Sun, Meng-Jiang Ding, Tian-Cai Cai, Hao-Jun Fan, Hong-Mei Gao, Jian-Peng Zhang
OBJECTIVES: To validate the effects of the new plateau hyperbaric chamber on alleviating high altitude hypoxia on Mount Kun Lun. METHODS: A prospective, controlled study of rabbits and adult volunteers was conducted at altitudes of 355, 2880 and 4532m. We obtained arterial blood samples from rabbits and volunteers before and after hyperbaric treatment. The respiratory rate, heart rate, and blood pressure (BP) of adult volunteers were monitored during hyperbaric treatment...
April 19, 2017: American Journal of Emergency Medicine
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