Document Detail


Free radical-mediated damage to barrier function is not associated with altered brain morphology in high-altitude headache.
MedLine Citation:
PMID:  15959459     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The present study combined molecular and neuroimaging techniques to examine if free radical-mediated damage to barrier function in hypoxia would result in extracellular edema, raise intracranial pressure (ICP) and account for the neurological symptoms typical of high-altitude headache (HAH) also known as acute mountain sickness (AMS). Twenty-two subjects were randomly exposed for 18 h to 12% (hypoxia) and 21% oxygen (O2 (normoxia)) for collection of venous blood (0 h, 8 h, 15 h, 18 h) and CSF (18 h) after lumbar puncture (LP). Electron paramagnetic resonance (EPR) spectroscopy identified a clear increase in the blood and CSF concentration of O2 and carbon-centered free radicals (P<0.05 versus normoxia) subsequently identified as lipid-derived alkoxyl (LO*) and alkyl (LC*) species. Magnetic resonance imaging (MRI) demonstrated a mild increase in brain volume (7.0+/-4.8 mL or 0.6%+/-0.4%, P<0.05 versus normoxia) that resolved within 6 h of normoxic recovery. However, there was no detectable evidence for gross barrier dysfunction, elevated lumbar pressures, T2 prolongation or associated neuronal and astroglial damage. Clinical AMS was diagnosed in 50% of subjects during the hypoxic trial and corresponding headache scores were markedly elevated (P<0.05 versus non-AMS). A greater increase in brain volume was observed, though this was slight, independent of oxidative stress, barrier dysfunction, raised lumbar pressure, vascular damage and measurable evidence of cerebral edema and only apparent in the most severe of cases. These findings suggest that free-radical-mediated vasogenic edema is not an important pathophysiological event that contributes to the mild brain swelling observed in HAH.
Authors:
Damian M Bailey; Robin Roukens; Michael Knauth; Kai Kallenberg; Stefan Christ; Alex Mohr; Just Genius; Birgitte Storch-Hagenlocher; Fabien Meisel; Jane McEneny; Ian S Young; Thorsten Steiner; Klaus Hess; Peter Bärtsch
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Publication Detail:
Type:  Comparative Study; Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism     Volume:  26     ISSN:  0271-678X     ISO Abbreviation:  J. Cereb. Blood Flow Metab.     Publication Date:  2006 Jan 
Date Detail:
Created Date:  2005-12-21     Completed Date:  2006-05-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8112566     Medline TA:  J Cereb Blood Flow Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  99-111     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Glamorgan, Pontypridd, UK. dbailey1@glam.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Adult
Altitude Sickness / diagnosis,  metabolism,  physiopathology*
Anoxia / metabolism
Atmosphere Exposure Chambers
Blood-Brain Barrier* / physiology
Brain / anatomy & histology,  metabolism,  physiopathology*
Electron Spin Resonance Spectroscopy / methods
Female
Free Radicals / metabolism
Headache / diagnosis,  metabolism,  physiopathology*
Humans
Magnetic Resonance Imaging / methods
Male
Organ Size
Oxidative Stress / physiology
Oxygen / metabolism
Oxygen Consumption / physiology
Reference Values
Sensitivity and Specificity
Severity of Illness Index
Chemical
Reg. No./Substance:
0/Free Radicals; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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