| PO2 measurements in the microcirculation using phosphorescence quenching microscopy at high magnification. | |
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MedLine Citation:
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PMID: 18375716 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In phosphorescence quenching microscopy (PQM), the multiple excitation of a reference volume produces the integration of oxygen consumption artifacts caused by individual flashes. We analyzed the performance of two types of PQM instruments to explain reported data on Po2 in the microcirculation. The combination of a large excitation area (LEA) and high flash rate produces a large oxygen photoconsumption artifact manifested differently in stationary and flowing fluids. A LEA instrument strongly depresses Po2 in a motionless tissue, but less in flowing blood, creating an apparent transmural Po2 drop in arterioles. The proposed model explains the mechanisms responsible for producing apparent transmural and longitudinal Po2 gradients in arterioles, a Po2 rise in venules, a hypothetical high respiration rate in the arteriolar wall and mesenteric tissue, a low Po2 in lymphatic microvessels, and both low and uniform tissue Po2. This alternative explanation for reported paradoxical results of Po2 distribution in the microcirculation obviates the need to revise the dominant role of capillaries in oxygen transport to tissue. Finding a way to eliminate the photoconsumption artifact is crucial for accurate microscopic oxygen measurements in microvascular networks and tissue. The PQM technique that employs a small excitation area (SEA) together with a low flash rate was specially designed to avoid accumulated oxygen photoconsumption in flowing blood and lymph. The related scanning SEA instrument provides artifact-free Po2 measurements in stationary tissue and motionless fluids. Thus the SEA technique significantly improves the accuracy of microscopic Po2 measurements in the microcirculation using the PQM. |
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Authors:
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Aleksander S Golub; Roland N Pittman |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2008-03-28 |
Journal Detail:
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Title: American journal of physiology. Heart and circulatory physiology Volume: 294 ISSN: 0363-6135 ISO Abbreviation: Am. J. Physiol. Heart Circ. Physiol. Publication Date: 2008 Jun |
Date Detail:
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Created Date: 2008-06-09 Completed Date: 2008-08-15 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100901228 Medline TA: Am J Physiol Heart Circ Physiol Country: United States |
Other Details:
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Languages: eng Pagination: H2905-16 Citation Subset: IM |
Affiliation:
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Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Arterioles / metabolism Artifacts Blood Flow Velocity Hemorheology Humans Luminescent Measurements Microscopy / instrumentation, methods* Models, Chemical Oxygen / blood*, chemistry Oxygen Consumption Partial Pressure Photochemistry Regional Blood Flow Venules / metabolism |
| Grant Support | |
ID/Acronym/Agency:
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HL-18292/HL/NHLBI NIH HHS; HL-79087/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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