uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Hearing loss in relation to round window membrane morphology in experimental chronic otitis media
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
2001 (English)In: Journal for Oto-Rhino-Laryngology, ISSN 0301-1569, E-ISSN 1423-0275, Vol. 63, no 6, 333-340 p.Article in journal (Refereed) Published
Abstract [en]

The present study was performed to test the effect of single and repeated Pseudomonas aeruginosa exotoxin A (PaExoA) instillations in the middle ear of the rat. The hearing level was examined by the ABR technique, round window membrane (RWM) thickness was measured and morphology was studied by light microscopy. The results showed both reversible and permanent hearing loss (HL). In animals that received a single dose of PaExoA, the RWM thickness doubled initially and remained thickened during the observation period. When PaExoA was instilled on several occasions, RWM thickness doubled, before decreasing to near-control levels. This study confirms the toxicity of PaExoA and the partially reversible HL occurring after a single application of the toxin. The diminished effect of repeated toxin instillations--despite the decreasing thickness of the RWM--is discussed.

Place, publisher, year, edition, pages
2001. Vol. 63, no 6, 333-340 p.
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:uu:diva-89796DOI: 10.1159/000055770PubMedID: 11713421OAI: oai:DiVA.org:uu-89796DiVA: diva2:161560
Available from: 2002-04-10 Created: 2002-04-10 Last updated: 2017-12-14Bibliographically approved
In thesis
1. The Round Window Membrane - Gateway to the Cochlea: A Morphological and Electrophysiological study
Open this publication in new window or tab >>The Round Window Membrane - Gateway to the Cochlea: A Morphological and Electrophysiological study
2002 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Topical treatment of several inner ear diseases through the round window membrane (RWM) might be feasible in the near future. Bacteria toxins, ototoxic drugs and noise trauma seem to harm the inner ear by a common pathway which involves, excessive outflow of the afferent neurotransmitter glutamate and formation of nitric oxide (NO), which can severely damage cells/nerve endings and lead to cell death.

In this study we used 98 Sprague-Dawley rats and seven human temporal bones. Various substances were instilled into the middle ear of the rat, such as Pseudomonas Aeruginosa Exotoxin (PaExoA), gentamicin, NO-inhibitor N-Omega-Nitro-L-Arginine Methyl Ester (L-NAME), and glucocorticoids. The effects of the substances were studied by morphological analysis of RWM and the endolymphatic sac (ES) by light and electron microscopic. Hearing level was measured in the rats by ABR technique. The human temporal bones were studied immunomorphologically to search for glutamate.

In the human inner ear, glutamate receptors and glutamine synthetase, were identified. In the rat, we found, following PaExoA exposure, reversible and permanent hearing loss and morphological changes in the RWM. The ES showed increased numbers of macrophages and thickening of the epithelia. When L-NAME was used as an otoprotector from gentamicin ototoxicity a therapeutic effect in the high frequency area was found. Hydrocortisone (but not dexamethasone) exposure of the RWM resulted in membrane thickening, and adjacent to the membrane, inflammatory cells.

The importance of the RWM as a portal for toxic substances and topical treatment of inner ear diseases was highlighted in this study. The difficulties of applying drugs in the round window niche were exposed. The results of this study add important knowledge concerning certain mechanisms of inner ear injury and help us to understand possibilities and problems of local treatment of inner ear diseases in patients.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2002. 33 p.
Series
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 0282-7476 ; 1134
Keyword
Otorhinolaryngology, round window membrane, pseudomonas exotoxin, auditory brainstem response, hearing loss, endolymphatic sac, inner ear immunology, glutamate, nitric oxide inhibitor, glucocorticoid., Otorhinolaryngologi
National Category
Otorhinolaryngology
Research subject
Oto-Rhino-Laryngology
Identifiers
urn:nbn:se:uu:diva-1969 (URN)91-554-5277-9 (ISBN)
Public defence
2002-05-03, Skoogsalen, ingång 78/79, 1 trappa, Uppsala, 13:15
Opponent
Available from: 2002-04-10 Created: 2002-04-10Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Authority records BETA

Nordang, LeifAnniko, Matti

Search in DiVA

By author/editor
Nordang, LeifAnniko, Matti
By organisation
Otolaryngology and Head and Neck Surgery
In the same journal
Journal for Oto-Rhino-Laryngology
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 498 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf