Document Detail

The in-vivo oxyhaemoglobin dissociation curve at sea level and high altitude.
MedLine Citation:
PMID:  23313855     Owner:  NLM     Status:  Publisher    
Animals native to hypoxic environments have adapted by increasing their haemoglobin oxygen affinity, but in-vitro studies of the oxyhaemoglobin dissociation curve (ODC) in humans show no changes in affinity under physiological conditions at altitudes up to 4000m. We conducted the first in-vivo measurement of the ODC; inducing progressive isocapnic hypoxia in lowlanders at sea level, acutely acclimatized lowlanders at 3600m, and native Andeans at that altitude. ODC curves were determined by administering isocapnic steps of increasing hypoxia, and measuring blood oxygen partial pressure and saturation. The ODC data were fitted using the Hill equation and extrapolated to predict the oxygen partial pressure at which haemoglobin was 50% saturated (P(50)). In contrast to findings from in-vitro studies, we found a pH-related reduction in P(50) in subjects at altitude, compared to sea-level subjects. We conclude that a pH-mediated increase in haemoglobin oxygen affinity in-vivo may be part of the acclimatization process in humans at altitude.
Dahlia Y Balaban; James Duffin; David Preiss; Alexandra Mardimae; Alex Vesely; Marat Slessarev; G R Zubieta-Calleja; Ernest R Greene; David B Macleod; Joseph A Fisher
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-8
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  -     ISSN:  1878-1519     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-15     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2013. Published by Elsevier B.V.
Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada.
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