Human Otitis Media Research Articles

Prediction of serous versus purulent otitis media by otoscopy and tympanometry in an animal model

Non-invasive methods for distinguishing different types of otitis media would have clinical value in predicting otologic morbidity. Two such methods, otoscopy and tympanometry, were used in two experimental models of otitis media to determine whether there are unique otoscopic and tympanometric characteristics of serous and purulent otitis media. A flat (type B or B+) tympanogram and yellow tympanic membrane each had a high likelihood of predicting middle ear effusion in these models, and the best prediction was obtained using both parameters simultaneously. A yellow tympanic membrane color predicted purulent otitis media in one model but did not distinguish purulent from serous ears in the other model. In one model, serous otitis media was frequently associated with a type C (negative pressure) tympanogram. Tympanometry provided a valuable adjunct to otoscopy in detecting effusion and in distinguishing serous and purulent disease. These observations may apply to otitis media in humans, although the variable etiologies of otitis media in humans may confound the ability of otoscopy and tympanometry to distinguish middle ear effusion types.

各種肉芽の骨破壊に対する影響

The precise role of skin and its products on chronic inflammatory bone destruction in middle ear cholesteatoma is still poorly understood.Inflammatory connective tissues produced in response to keratinizing epithelium, carrageenan and granuloma from open wound in the skull of rat were analyed for bone resorbing activity to determine their importance in chronic imflammatory bone resorption.Granuloma were induced in rats under the frontal scalp with three different methods:1. As the standard granuloma inducing agent, carrageenan in the form of 1% suspension was injected.2. Wounds were produced in the frontal area of the scalp by incising skin and suturing the edge back to prevent epithelial closure.3. Keratin and epithelium debris were removed from rat skin, dried, powered and injected as 1% suspension.The resulting granulation tissue was excised at one, two, and four weeks after induction, examined chemically.Prostaglandine E2 (PG E2) was measured by radioimmunoassay. Osteoclast activating factor (OAF) was determined with a pre-labeled fetal bone tissue culture assay. Leucine aminopeptidase (LAP) was determinend with a coloremetric assay.Although there was variability among different samples of each granuloma, keratin granuloma produced the highest OAF activity with little decline at four weeks after induction. OAF activity from carrageenan granuloma at one and two weeke is just slightly below the activity of keratin granuloma. Wound granuloma and keratin granuloma exhibited higher PG E2 levels than did carrageenan granuloma or normal skin. The highest levels of PG E2 were found two weeks after induction. Levels of LAP in various granulomas at one week after induction were considerably higher than that of normal skin, but differed little from one another.The presence of numerous macrophages in various granulomas correlated with the degree of activity of bone resorption noted chemically. This would tend to highlight the importance of OAF, PG E2 and LAP in the resorption induced by macrophage.It leads to the conclusion that keratin debris enhances the bone resorbing capacity of granulation tissue in rats just as it does in human otitis media.

Experimental otitis media after nasal inoculation of Streptococcus pneumoniae and influenza A virus in chinchillas.

Otitis media developed in 67% of chinchillas inoculated intranasally with type 7 Streptococcus pneumoniae and influenza A virus. Only 4% of chinchillas inoculated with influenza alone and 21% of chinchillas inoculated with S. pneumoniae alone developed otitis media. Among the chinchillas that developed otitis media after inoculation with both pneumococcus and influenza, 73% of the affected ears contained effusion, and 27% of the affected ears showed tympanic membrane inflammation without middle ear effusion obtained on paracentesis. Although a majority of the ears with effusion yielded S. pneumoniae on culture, one-third of the effusions were sterile for aerobic bacteria. This model resembles conditions accompanying otitis media in humans and suggests that respiratory viral infection contributes significantly to the pathogenesis of acute otitis media.

Experimental Viral Infections of the Temporal Bone. I. Experimental Otitis Media Due to Vaccinia Virus in Hamsters

Clinical and pathologic studies of patients with smallpox suggest that conductive hearing loss is a frequent complication of smallpox and that it is due to otitis media. A possible experimental model for this hearing loss has been developed by study of the pathogenesis of acute vaccinia virus infections of hamster middle ears. Infant hamsters developed severe necrotic otitis media, and vaccinia viral antigen was demonstrated by fluorescent antibody staining in large confluent areas of epithelial cells lining the middle ear. Juvenile hamsters developed a patchy, less severe infection of the middle ear, most of which present along the tympanic membrane and middle ear ossicles, Adult hamsters did not develop middle ear infection. These findings support the argument that variola (smallpox) virus can cause otitis media in humans and that viral infection of the middle ear may be the cause of hearing loss.