Concentration of nitric oxide metabolites in middle ear effusion.

Free radicals such as nitric oxide (NO) seem to be important in the pathogenesis of otitis media with effusion (OME). NO can be quantitated by measuring its metabolites, nitrate (NO(3)(-)) and nitrite (NO(2)(-)). The purpose of this study is to determine the concentrations of NO in human middle ear effusion (MEE). Samples of human MEE were collected at the time of myringotomy and tympanostomy tube insertions. The type of MEE was classified as serous (SOM), mucoid (MOM) or purulent (POM) at the time of surgery. Samples of MEE were assayed for NO metabolites (nitrate and nitrite) with colorimetric assay (Griess method). Concentrations of NO metabolites were highest in MOM followed by SOM and POM. This study suggests that NO is present in human MEE and may play an important role in the pathogenesis of OME.