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The effects of changing middle ear pressure and gas partial pressure on mucosal blood flow and vascular permeability in the chinchilla

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dc.contributor.author Alper, C.M.
dc.contributor.author Ardic, F.N.
dc.contributor.author Doyle, W.J.
dc.date.accessioned 2019-08-16T11:48:59Z
dc.date.available 2019-08-16T11:48:59Z
dc.date.issued 2000
dc.identifier.issn 03858146 (ISSN)
dc.identifier.uri http://acikerisim.pau.edu.tr:8080/xmlui/handle/11499/5538
dc.description.abstract Objective: To determine if middle ear (ME) gas composition and/or total pressure regulates local mucosal blood flow (MBF) and vascular permeability. The hypotheses tested are: (1) relatively high local CO 2 tensions and/or low O 2 tensions increase the ME MBF and vascular permeability; and (2) sub- atmospheric total ME pressure provokes similar effects. Methods: The responses of ME MBF and vascular permeability parameters were measured during 60 min exposures of chinchilla MEs to one of two test gas mixtures (16.3% O 2 , 5.1% CO 2 , balance N 2 , or 5.3% O 2 , 15.6% CO 2 , balance N 2 ) applied at different levels of underpressure (ref. ambient). In the first set of experiments (n=19), mucosal perfusion parameters were recorded using a Laser Doppler Flowmeter for 60 min before and 60 min after exposure to the experimental conditions. In the second set of experiments (n=19 chinchillas, 38 ears), the MEs were exposed to the gas mixtures and then maintained for 60 min at ambient pressure or at negative pressures of -200, -400, -600 mmH 2 O. Fifty minutes into the experiment, the animals were injected intravenously with 60 mg/kg of horseradish peroxidase (HRP). The animals were killed and existing effusion was aspirated, its volume recorded and then analyzed for total protein. From surface preparations of the ME mucosa, vascular leakage sites were measured as percent total surface area using an image analysis program with the threshold window set to discriminate HRP stain. Results: Throughout the 120 min in the first set of experiments, the measured MBF parameters decreased in all exposure groups. Comparisons among groups for the absolute magnitude of the change from baseline showed that high local CO 2 partial pressures decreased MBF and ME underpressures increased MBF, but the effects did not achieve statistical significance. The results of the second set of experiments demonstrated no effect of gas composition on any of the measured parameters of vascular permeability. All measures of permeability were linearly related to the magnitude of the underpressure. Conclusion: These data support a role for total ME pressure, but not CO 2 partial pressure in regulating ME MBF and vascular permeability. (C) 2000 Elsevier Science Ireland Ltd.
dc.language.iso English
dc.relation.isversionof 10.1016/S0385-8146(99)00053-X
dc.subject Chincilla
dc.subject Middle ear pressure
dc.subject Mucosal blood flow
dc.subject animal experiment
dc.subject animal model
dc.subject animal tissue
dc.subject article
dc.subject blood vessel permeability
dc.subject capillary
dc.subject carbon dioxide tension
dc.subject chinchilla
dc.subject controlled study
dc.subject effusion
dc.subject middle ear
dc.subject middle ear pressure
dc.subject mucosa
dc.subject nonhuman
dc.subject oxygen tension
dc.subject Animals
dc.subject Capillary Permeability
dc.subject Chinchilla
dc.subject Ear, Middle
dc.subject Gases
dc.subject Mucous Membrane
dc.subject Partial Pressure
dc.subject Pressure
dc.title The effects of changing middle ear pressure and gas partial pressure on mucosal blood flow and vascular permeability in the chinchilla
dc.type Article
dc.relation.journal Auris Nasus Larynx
dc.identifier.volume 27
dc.identifier.issue 2
dc.identifier.startpage 105
dc.identifier.endpage 111
dc.identifier.index Scopus

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