Lysosomal thiol proteases (cathepsin B-like proteases) in serous middle ear effusions from adult patients.
Hydrolytic activity of cathepsins B, H and trypsin-like proteases was measured in 38 serous middle ear effusion (MEE) samples. The concentrations of (alpha 1-AT) and alpha 2-macroglobulin (alpha 2-M) were also quantitated. The mean value of cathepsin B activity was 25.0 +/- 20.7 RFU and that of cathepsin H was 14.3 +/- 3.0--both significantly higher than those in plasma (1.8 +/- 0.4 RFU, 1.2 +/- 0.3 RFU, p less than 0.005). Very low trypsin-like protease activity could be observed. The mean concentrations of alpha 1-AT and alpha 2-M were 368 +/- 94.8 mg/dl and 57.5 +/- 57.3 mg/dl. The bulk of alpha 1-AT in MEEs was occupied by free alpha 1-AT, which can saturate exogenous trypsin. Due to the very low molar concentration of alpha 2-M in MEEs, thiol proteases (mainly cathepsin B) could be a possible major factor inflicting proteolytic injury on the middle ear mucosa and reflecting the severity of the inflammatory process.
Hamaguchi
Y
Y
Sakakura
K
K
Majima
Y
Y
Sakakura
Y
Y
Miyoshi
Y
Y
D000328:Adult; D000418:Albumins / Q000032:analysis; D002401:Cathepsin B; D056655:Cathepsin H; D002403:Cathepsins / Q000032:analysis; D003546:Cysteine Endopeptidases; D010450:Endopeptidases / Q000032:analysis*; D005260:Female; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D008247:Lysosomes / Q000201:enzymology*; D008297:Male; D010034:Otitis Media with Effusion / Q000201:enzymology*; D000515:alpha 1-Antitrypsin / Q000032:analysis; D000511:alpha-Macroglobulins / Q000032:analysis
D000418:Albumins; D000515:alpha 1-Antitrypsin; D000511:alpha-Macroglobulins; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; C534126:CTSH protein, human; D056655:Cathepsin H