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Eriksson, Per-Olof
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Publications (3 of 3) Show all publications
Eriksson, P. O., Mattsson, C. & Hellström, S. (2003). First forty-eight hours of developing otitis media: An experimental study. Annals of Otology, Rhinology and Laryngology, 112(6), 558-566
Open this publication in new window or tab >>First forty-eight hours of developing otitis media: An experimental study
2003 (English)In: Annals of Otology, Rhinology and Laryngology, ISSN 0003-4894, E-ISSN 1943-572X, Vol. 112, no 6, p. 558-566Article in journal (Refereed) Published
Abstract [en]

The early inflammatory changes in the tympanic membrane were explored in 2 rat models. Acute otitis media was induced by instillation of Streptococcus pneumoniae type 3 into the middle ear cavity, and otitis media with effusion was induced by blockage of the eustachian tube. Otomicroscopic examination was performed before the rats were painlessly sacrificed at 3, 6, 9, 12, 18, 24, or 48 hours after initiation of the otitis media conditions. The tympanic membrane was studied by light and electron microscopy. Both acute otitis media and otitis media with effusion caused early inflammatory changes of the tympanic membrane, and the pars flaccida was the portion that reacted first. The inflammatory alterations were most pronounced in the acute otitis media model. The course of inflammation showed a bimodal pattern with an early deposition of a filamentous material with a band pattern, typical of fibrin. Despite a fluid-filled middle ear cavity, the inflammatory changes in the otitis media with effusion model were moderate, as was consistent with the clinical appearance of the tympanic membrane.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:umu:diva-3348 (URN)12834127 (PubMedID)
Available from: 2004-01-19 Created: 2004-01-19 Last updated: 2018-06-09Bibliographically approved
Hellström, S., Spratley, J., Eriksson, P.-O. & Pais-Clemente, M. (2003). Tympanic membrane vessel revisited: a study in an animal model. Otology and Neurotology, 24(3), 494-499
Open this publication in new window or tab >>Tympanic membrane vessel revisited: a study in an animal model
2003 (English)In: Otology and Neurotology, ISSN 1531-7129, E-ISSN 1537-4505, Vol. 24, no 3, p. 494-499Article in journal (Refereed) Published
Abstract [en]

HYPOTHESIS: The present study aimed at elucidating whether there are blood vessels in the semitransparent portion of the tympanic membrane.

BACKGROUND: The normal semitransparent portions of pars tensa show strikingly few, small-caliber vessels under the otomicroscope. The major portion of a pars tensa seems to be devoid of blood vessels. In inflammatory conditions of the middle ear, the vascular pattern of the tympanic membrane is dramatically altered, and blood vessels traversing the pars tensa can be discernable.

METHODS: The study was performed in rats with healthy tympanic membranes and in tympanic membranes obtained from animals with purulent otitis media evoked by inoculation of Str. pneumoniae. The tympanic membrane vessels were dilated by injection of adenosin, and directly afterwards the animal was perfused with china ink. Vessels were also revealed by immunohistochemistry with antibodies for Thy-1 and the von Willebrand factor as well as by detection of carbon particles at an ultrastructural level.

RESULTS: Adenosin caused a marked dilation of the mallear and annular vessels. However, no preexisting vasculature was revealed in the normally transparent portions of the pars tensa except single vessels in the posterior quadrant and in the lower quadrants. In Str. pneumoniae-induced acute otitis media, the tympanic membrane thickened, bulged, and discolored. Even then, at 12 hours after inoculation, no vessels could be distinguished in the normally transparent portions of the tympanic membrane. However, at 4 and 7 days of acute purulent otitis media, vessels developed in those areas, most probably through ingrowth of newly formed vessels.

CONCLUSION: The results support the view that the semitransparent portions of the pars tensa lack vascularity. In inflammation, new vessels are formed in pars tensa to meet the demand for an increased blood supply.

Identifiers
urn:nbn:se:umu:diva-37255 (URN)12806306 (PubMedID)
Available from: 2010-10-22 Created: 2010-10-22 Last updated: 2018-06-08Bibliographically approved
Spratley, J., Hellström, S., Eriksson, P.-O. & Pais-Clemente, M. (2002). Myringotomy delays the tympanic membrane recovery in acute otitis media: a study in the rat model. The Laryngoscope, 112(8 Pt 1), 1474-1481
Open this publication in new window or tab >>Myringotomy delays the tympanic membrane recovery in acute otitis media: a study in the rat model
2002 (English)In: The Laryngoscope, ISSN 0023-852X, E-ISSN 1531-4995, Vol. 112, no 8 Pt 1, p. 1474-1481Article in journal (Refereed) Published
Abstract [en]

BACKGROUND/HYPOTHESIS: Acute otitis media is a major cause of visits to pediatric health care providers. Myringotomy in uncomplicated acute otitis media is debatable today. The study addressed this problem through the otomicroscopic and histopathological observations of the events occurring in the tympanic membrane during the first week after myringotomy.

STUDY DESIGN: Randomized study in an experimental animal model.

METHODS: Under anesthesia, the left middle ear of 36 Sprague-Dawley rats was inoculated with Streptococcus pneumoniae type 3. Forty-eight hours later, at day 0, four animals were immediately killed and the remaining animals were randomly assigned into a myringotomy group (n = 16, myringotomy on the left ear) and a non-myringotomy group (n = 16, otomicroscopy without myringotomy). Otomicroscopy and killings were performed in series of four animals from each group at days 1, 2, 4, and 7 after myringotomy. Tympanic membranes were collected after fixation and processed for light and electron microscopy.

RESULTS: All inoculated ears showed a manifest acute otitis media at day 0. An intense infiltration by inflammatory cells and edema distorted severely the tympanic membrane structure. These findings decreased the following days. However, inflammation as evaluated by the thickness and the cytoarchitecture of the tympanic membrane layers, recovered significantly faster in the membranes in the non-myringotomy group. At day 7, all tympanic membranes in the myringotomy group were closed by a hypertrophic keratinizing epithelium and a remodeling connective tissue layer, whereas the animals in the non-myringotomy group had a residual edema in the lamina propria.

CONCLUSIONS: The present infectious model induced an intense inflammatory reaction within the entire structure of the tympanic membrane. Myringotomy provoked a delayed recovery from the inflammatory process within the tympanic membrane. Therefore, if applicable to human conditions, the use of myringotomy in the management of acute otitis media should be restricted to selected cases of acute otitis media.

Keywords
Otitis media;tympanic membrane;myringotomy;rat;Streptococcus pneumoniae
Identifiers
urn:nbn:se:umu:diva-37257 (URN)10.1097/00005537-200208000-00027 (DOI)12172265 (PubMedID)
Available from: 2010-10-22 Created: 2010-10-22 Last updated: 2018-06-08Bibliographically approved
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