| Acid-base changes during complete brain ischemia. | |
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MedLine Citation:
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PMID: 2122556 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We examined the proposal that preischemic hyperglycemia causes exaggerated brain damage by decreasing intracellular or extracellular pH to below a specified threshold value. We also provide a critical appraisal of two related hypotheses. The first is that hyperglycemia enhances brain damage by causing excessive intraglial acidosis; the second, that the critical degree of acidosis is reached not during the ischemia but when recirculation is instituted. The following conclusions are drawn. First, the evidence is inconclusive in favor of marked compartmentation of H+ during ischemia, based on a discontinuous delta lactate/delta PCO2 relation and on direct intracellular pH measurements. In fact, results obtained with identical techniques in normoglycemic animals suggest that the acid compartment assumed to be glia is very small and may be of another origin. Second, although recirculation may give rise to a further increase in either extracellular or intracellular acidosis under certain conditions, this acidosis is not a prerequisite for increased tissue damage or infarction. Third, a critical appraisal of reports supports the contention that enhanced damage is triggered below a specified threshold pH value. In complete or near-complete ischemia, this value corresponds to a tissue lactate content of 17-20 mM.kg-1 wet wt. No correlation exists between subthreshold values for delta lactate and the severity of tissue damage. Furthermore, hyperglycemia cannot be expected to enhance damage if conditions prevent lactate from reaching threshold values or if they uncouple changes in lactate and pH. |
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Authors:
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B K Siesjö; A Ekholm; K Katsura; S Theander |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.; Review |
Journal Detail:
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Title: Stroke; a journal of cerebral circulation Volume: 21 ISSN: 0039-2499 ISO Abbreviation: Stroke Publication Date: 1990 Nov |
Date Detail:
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Created Date: 1990-12-20 Completed Date: 1990-12-20 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0235266 Medline TA: Stroke Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: III194-9 Citation Subset: IM |
Affiliation:
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Laboratory for Experimental Brain Research, University of Lund, Sweden. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acid-Base Equilibrium Acidosis / metabolism* Acidosis, Lactic / metabolism Adenosine Triphosphate / metabolism Bicarbonates / metabolism* Brain Ischemia / metabolism* Carbon Dioxide / metabolism Electrolytes / metabolism Extracellular Space / metabolism Glucose / metabolism Hydrogen-Ion Concentration Hyperglycemia / metabolism Neuroglia / metabolism Neurons / metabolism |
| Grant Support | |
ID/Acronym/Agency:
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5-RO1//PHS HHS |
| Chemical | |
Reg. No./Substance:
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0/Bicarbonates; 0/Electrolytes; 124-38-9/Carbon Dioxide; 50-99-7/Glucose; 56-65-5/Adenosine Triphosphate |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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