A study of mucus glycoproteins in secretory otitis media.

Rheologically active mucus glycoproteins (mucins) were isolated from the middle ear effusions of 282 patients (344 ears) with secretory otitis media. Middle ear mucins from those patients with no other associated pathology were compared biochemically and biophysically with mucins from patients where a specific associated pathology was present. The most striking biochemical variation was total carbohydrate content, which was lowest for mucins derived from purulent secretions in general (30.9%) and mucoid secretions from patients with cleft palates (32%). Furthermore, the carbohydrate content was correlated with the rheologic activity of reconstituted mucins, both in dilute solution and in the gel state. All mucins had high intrinsic viscosities, sensitive to ionic strength and the mucolytic N-acetylcysteine. Transport studies indicated that certain middle ear effusions, particularly those from patients with cleft palates, may not be cleared from the middle ear because of insufficient viscoelasticity.