[Biochemical differences in middle ear effusions between pediatric and adult patients, (II). The protein composition].
To clarify the biochemical differences between pediatric and adult middle ear effusions (MEEs) in secretory otitis media with effusion (OME), we analyzed the protein components from MEEs of 3 children and 3 adults by electrophoresis. High molecular protein components (280 and 265 kDa proteins), which contained in sera in the concentrations less than 2.5%, were not detected in MEEs even in trace amounts. The protein components which molecular weights were less than 260 kDa are transferred from sera into MEEs in a same proportion as in sera. Mucin type glycoprotein was comprised about 30% of the total protein in pediatric mucous MEEs and the weight ratio of mucin to albumin in pediatric mucous MEEs was 2.69, but serous MEEs from adult patients did not contain mucin. Immunoglobulin (IgA, IgG and IgM) concentrations in pediatric mucous MEEs were same as in adult serous MEEs. The concentrations of IgA and IgM in MEEs were higher than in sera. Lysozyme concentration in MEEs was also higher than in sera, and that in pediatric mucous MEEs was nearly 2 times higher than serous MEEs from adult patients.