| Perfusion and diffusion limitations in middle ear gas exchange: the exchange of CO2 as a test case. | |
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MedLine Citation:
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PMID: 20338231 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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A long standing debate on perfusion/diffusion limitations in the context of middle ear (ME) gas exchange was revisited using data obtained from previous iso-pressure gas-exchange measurements in different mammals. We tried to determine whether the exchange of CO(2) in the ME is limited by perfusion or by diffusion by comparing the mass specific cardiac output (msQ) and the mass specific initial CO(2) flow rate into air-washed MEs (msV(i) CO(2)) of rabbits and rats. Based on previously published allometry at rest, the msQ was 0.154 mL/(min g) in rabbits (mean body weight: 2800 g) and 0.259 mL/(min g) in rats (mean body weight: 179.1 g); msV(i) CO(2) (Delta t=0) was 0.109+/-0.047 microL/(h g) in rabbits (n=16) and 0.170+/-0.094 microL/(h g) in rats (n=9). Similar ratios were found when an allometric comparison was made between the ratio of msV(i) CO(2) (Delta t=0) (approximately 0.64), and the ratio of msQs (approximately 0.59) in rabbits and rats. If the active mucosal surface areas of MEs of rabbits and rats are directly proportional to their masses as are the masses of their hearts and if their msQs are proportional to the rates of blood flows in the ME mucosa, these results support the assumption that the exchange of CO(2) in the ME of mammals is mainly perfusion (and not diffusion) dependent. |
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Authors:
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Yael Marcusohn; Amos Ar; Joris J J Dirckx |
Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't Date: 2010-03-23 |
Journal Detail:
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Title: Hearing research Volume: 265 ISSN: 1878-5891 ISO Abbreviation: Hear. Res. Publication Date: 2010 Jun |
Date Detail:
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Created Date: 2010-05-18 Completed Date: 2010-08-24 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7900445 Medline TA: Hear Res Country: Netherlands |
Other Details:
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Languages: eng Pagination: 11-4 Citation Subset: IM |
Copyright Information:
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2010 Elsevier B.V. All rights reserved. |
Affiliation:
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Laboratory of Biomedical Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp B-2020, Belgium. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Biological Transport Body Size Carbon Dioxide / blood, metabolism* Cardiac Output Diffusion Ear, Middle / blood supply*, metabolism* Gases Models, Cardiovascular Mucous Membrane / blood supply, metabolism Perfusion Rabbits Rats Rats, Sprague-Dawley Regional Blood Flow |
| Chemical | |
Reg. No./Substance:
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0/Gases; 124-38-9/Carbon Dioxide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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