Lysosomal Hydrolases in Middle Ear Effusions

Abstract

Biochemical studies of middle ear effusions have demonstrated generally higher levels of certain hydrolytic and oxidative enzymes in mucoid fluids when compared to serous. We have extended these studies by analyzing middle ear effusions for the content of a large number of lysosomal hydrolases. The mean specific activity for α-glucosidase in mucoid fluids was found to be ten times that for serous fluids while α-mannosidase, β-glucuronidase, hexosaminidase, acid phosphatase, β-galactosidase, alkaline phosphatase, and lactate dehydrogenase were found to be three to five times greater in mucoid than serous effusions. In this study the specific enzyme activities for lysosomal hydrolases from purulent effusions were found to be intermediate between the activities in serous and mucoid effusions. No significant correlation was found between the specific activities of lysosomal hydrolases and the presence or absence of bacteria in mucoid or serous middle ear effusions. The hexosaminidase isozyme distribution was found to be identical for serous and mucoid fluids and similar to that found in human serum. However, the isozyme pattern of β-glucuronidase in mucoid effusions was significantly different than that in normal human serum as mucoid fluids contain a large amount of an anionic isoenzyme of β-glucuronidase that is barely detectable in human serum.