Journal ArticleDOI
Decreased ventilation and hypoxic ventilatory responsiveness are not reversed by naloxone in Lhasa residents with chronic mountain sickness
Shinfu Sun,S. Y. Huang,J. G. Zhang,Tarshi Droma,G. Banden,R. E. McCullough,R. G. McCullough,Allen Cymerman,John T. Reeves,Lorna G. Moore +9 more
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TLDR
Reduced forced expiratory volume in 1 s to vital capacity ratios (FEV1/VC) and a higher proportion of cigarette smokers in the group of patients with CMS compared with control subjects suggested that at least some patients had mild airway obstructive lung disease.Abstract:
Persons with chronic mountain sickness (CMS) hypoventilate and are more hypoxemic than normal individuals, but the cause of the hypoventilation is unclear. Studies of 14 patients with CMS and 11 healthy age-matched control subjects residing in Lhasa, Tibet, China (3,658 m) were conducted to test the hypothesis that hypoventilation, blunted hypoxic ventilatory responsiveness (HVR), and hypoxic ventilatory depression of CMS were due to increased endogenous opioid production. Patients with CMS compared with control subjects exhibited hypoventilation (end-tidal carbon dioxide pressure [PETCO2] = 36.6 +/- 1.0 versus 31.5 +/- 0.5 mm Hg, p less than 0.05), lower tidal volume (VT = 0.54 +/- 0.02 versus 0.61 +/- 0.02 ml BTPS, p less than 0.05), blunted HVR (shape parameter A = 17 +/- 8 versus 114 +/- 22 mm Hg/L BTPS/min, p less than 0.05), and a depressant effect of ambient hypoxia on ventilation (delta PETCO2 with acute hyperoxia = -3.5 +/- 0.5 versus -1.0 +/- 0.6 mm Hg, p less than 0.05). Reduced forced expiratory volume in 1 s to vital capacity ratios (FEV1/VC) and a higher proportion of cigarette smokers in the group of patients with CMS compared with control subjects suggested that at least some patients with CMS had mild airway obstructive lung disease. Naloxone infusion (0.14 mg/kg) to six patients with CMS did not change resting VT, PETCO2, HVR, or SaO2.(ABSTRACT TRUNCATED AT 250 WORDS)read more
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Journal ArticleDOI
Human adaptation to high altitude: regional and life-cycle perspectives.
TL;DR: Tibetans have several physiological distinctions that confer adaptive benefit consistent with their probable greater generational length of high-altitude residence, and 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.
Journal ArticleDOI
Human genetic adaptation to high altitude.
TL;DR: Recent studies which address the question as to whether genetic adaptation to high altitude has occurred and suggest that Tibetans are better adapted are reviewed.
Journal ArticleDOI
Ventilation and hypoxic ventilatory response of Tibetan and Aymara high altitude natives
Cynthia M. Beall,Kingman P. Strohl,John Blangero,Sarah Williams-Blangero,Laura Almasy,Michael J. Decker,Carol M. Worthman,Melvyn C. Goldstein,Enrique Vargas,Mercedes Villena,Rudy Soria,Ana Maria Alarcon,Cristina Gonzales +12 more
TL;DR: Within populations, greater severity of hypoxia 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.
Journal ArticleDOI
Comparative human ventilatory adaptation to high altitude.
TL;DR: It is indicated that Tibetans ventilate more than Andean high-altitude natives residing at the same or similar altitudes (PET[CO(2)]) in Tibetans+/-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.
Journal ArticleDOI
Ventilation and hypoxic ventilatory responsiveness in Chinese-Tibetan residents at 3,658 m
TL;DR: Although longer duration of high-altitude residence appears to progressively blunt HVR among Han-Tibetans born and residing at 3, 658 m, their Tibetan ancestry appears protective in their maintenance of high resting ventilation levels despite diminished chemosensitivity.
References
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Journal ArticleDOI
Opioids and breathing
T. V. Santiago,N. H. Edelman +1 more
TL;DR: It is felt that the effects of endogenous opioids on the control of breathing will probably be one of modulating the responses to drugs or nociceptive respiratory stimuli through inhibitory pathways.
Journal ArticleDOI
Some clinical aspects of life at high altitudes
TL;DR: Excerpt Continuous exposure to a high-altitude environment, where the lowered partial pressure of the oxygen in the inspired air originates a certain degree of hypoxia, demands some adaptative mech...
Journal ArticleDOI
Chronic cor pulmonale due to loss of altitude acclimatization (chronic mountain sickness)
Dante Peñaloza,Francisco Sime +1 more
TL;DR: There is enough clinical, physiologic and anatomic basis to conclude that Monge's disease is a variety of chronic cor pulmonale due to alveolar hypoxia, and muscularization of the pulmonary arteries and reversion of clinical and physiologic findings are also features common to the hypoxic type of chronic Cor pulmonales.
Journal ArticleDOI
Maternal hypoxic ventilatory response, ventilation, and infant birth weight at 4,300 m.
TL;DR: An increase in HVR may be an important contributor to increased maternal ventilation with pregnancy and infant birth weight at high altitude.
Journal ArticleDOI
Chronic Mountain Sickness in Tibet
TL;DR: Haemodynamic investigations show pulmonary hypertension with a normal cardiac output and dilatation of the right ventricle in the long-established case, and investigatory data suggest that the earlier stages of the disease are dominated by polycythaemia, while cardiopulmonary involvement increases with the duration of the Disease.