Ulf Renvall

Collagenase Activity in Middle Ear Effusions

Collagenolytic enzyme activity has been demonstrated in middle ear effusions from patients suffering from otitis media with effusion. Collagenase activity was characterized using different biochemical techniques. Various chemical and physical parameters were titrated for optimal enzyme activity. Bivalent cations activated the enzyme with Ca2+ as the most potent activator. Chelators such as EDTA reduced the enzyme at low concentrations. The enzyme was found to have a higher specific activity in mucoid effusions than in serous and had characteristics similar to granulocyte derived collagenase from human leukocytes. Possible relationships between the presence of collagenase activity and tissue destruction in the middle ear after otitis media with effusion are discussed. The collagenase activity showed wide ranges within different categories of middle ear effusions.

Identification of Middle Ear Disease

Since impedance measurements were introduced as a mean of identifying ears affected by middle ear disease, efforts have been concentrated on the identifying of ears in which effusion is present. The shape of the tympanogram has been analysed and it has been proposed that ears producing a shallow tympanometric pattern are more likely to contain fluid in the middle ear, than are ears having a tympanogram with a large peak. In this communication and great individual variation of tympanograms is shown and it is suggested that two categories of tympanogram should be considered, namely 1) flat tympanogram, and 2) tympanograms in which the middle ear pressure can be determined.

Ear discharge after insertion of transmyringeal tubes

The peroperative bacteriology and cytology of the middle ear have been studied in 103 ears in 65 children operated on due to longstanding secretory otitis media. Within one month postoperatively, 12 ears (12%) showed signs of infection with discharge from the tube. Ten out of these 12 ears showed peroperative growth of Hemophilus influenzae, Branhamella catarrhalis, pneumococci or staphylococci in the middle ear effusions, a significant difference compared to ears without postoperative discharge. The peroperative cytological evaluation of the middle ear effusions from 10 out of the 12 patients with postoperative ear discharge showed presence of phagocytes as a sign of infection. It is concluded that pre-existing bacteria in the middle ear effusion of patients with longstanding secretory otitis media might increase the risk of postoperative infection within the first month after insertion of transmyringeal tubes.

Late results after cholesteatoma surgery in early childhood.

The incidence of cholesteatoma in children living in an urban area of western Sweden has been studied. The total population of this area is 470,000 out of which 100,000 are children, 16 years or younger. The charts of all the children undergoing cholesteatoma surgery during the time period from 1977 to 1986 were collected and analyzed. Only those patients who had not been exposed to cholesteatoma surgery before were included. In a follow-up study the clinical situation and hearing level have been evaluated 4 years or more after surgery. Nineteen patients, that is an incidence of 0.4 children out of 100,000 inhabitants each year, were found meeting these criteria with an irregular distribution over the 10 year period. During the first two years 11 cases were found, but in the following 8 years only 8 new cases were identified. Intact wall tympanoplasty was used in 10 cases and canal wall down operation in 9 cases. Residual cholesteatoma was detected in 6 cases and recurrent cholesteatoma in one case. Six of these had an intact wall tympanoplasty and all but one were later reoperated with a canal wall down approach. The study reveals a decrease in the incidence of cholesteatoma in children over a 10-year period. The more frequent use of tympanometry and otomicroscopy is a possible explanation.

Proteinase activity in effusion from children with otitis media with effusion

Abstract Proteinase activity has been demonstrated in middle ear effusions from patients suffering from otitis media with effusion. Proteinase activity was characterized by various biochemical, chemical and physical parameters. Chelators and sulfhydryl group reacting substances reduced the enzyme activity. Enzyme activity was positively correlated to the number of granulocytes present in the effusion. No correlation to bacteriological findings or to tympanic was and the proteinase activity showed wide within different categories of middle ear effusions.

Biochemical characterization of collagenase activity from middle ear effusions.

Collagenolytic enzyme activity has been demonstrated in middle ear effusions from patients suffering from otitis media with effusion. Collagenase activity was characterized using different biochemical techniques. The enzyme was found to have a higher specific activity in mucoid effusions and had characteristics similar to granulocyte derived collagenase from human leucocytes.