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- Lundquist, Per-Gotthard, 1937-, et al.
(author)
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Effect of carbon dioxide on cochlear blood flow in guinea pigs
- 2000
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In: Acta Oto-Laryngologica. - 0001-6489 .- 1651-2251. ; 120:1, s. 11-18
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Journal article (peer-reviewed)abstract
- The influence of carbon dioxide (CO2) on cochlear blood flow (CBF), blood pressure (SBP) and skin blood flow (SBF) was studied in anaesthetized guinea pigs. A transient acute respiratory acidosis was produced by inhalation of CO2 and oxygen (O2) gas mixtures. The blood flows were measured by laser Doppler flowmetry (LDF). High CO2 increased CBF and SBP, and decreased SBF in a dose-dependent manner. The responses of CBF, SBP and SBF to high CO2 were reversible. Our results indicate that high CO2 (and low pH) dilates the smooth muscle of the blood vessels, resulting in an increase in CBF. CO2 also activates the sympathetic nervous system in the whole body, producing an increase in SBP. The distribution of alpha- adrenergic fibres/receptors is abundant in skin and scarce in the cochlea. The constrictive effect on blood vessels is much greater in the skin than in the cochlea, thus our results showed a decrease in SBF during stimulation with higher CO2.
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- Sundberg, Mikael, et al.
(author)
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Diffuse reflectance spectroscopy of the human tympanic membrane in otitis media
- 2004
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In: Physiological Measurement. - : IOP Publishing. - 0967-3334 .- 1361-6579. ; 25:6, s. 1473-1483
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Journal article (peer-reviewed)abstract
- We have investigated if features in the diffuse reflectance spectra from in vivo spectroscopic measurements of the tympanic membrane could aid the diagnosis of otitis media in children. Diffuse reflectance spectroscopy, in the visible wavelength range, was used in 15 ears from children with otitis media with effusion before and after myringotomy and in 15 healthy ears as a reference. Two previously published erythema detection algorithms yielded numerical quantities of haemoglobin content. With a combination of the algorithms, induced erythema (after myringotomy) was distinguished from healthy ears using Student's t-test (p < 0.01). Otitis media with mucous effusion was distinguished from (1) otitis media with serous effusion, (2) induced erythema and (3) healthy ears, (p < 0.05) using Student's t-test for independent groups and the paired t-test for dependent groups. Our results imply that reflectance spectroscopy is a promising technique to be used for the diagnosis of otitis media.
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