[' ', '|', 'airways,', 'but', 'there', 'appear', 'to', 'be', 'differences', 'in', 'the', 'response', 'of', 'the', 'cells', 'to', 'these', 'compounds.', 'Additional', 'experiments', 'have', 'been', 'caried', 'out', 'using', 'monolayer', 'cultures', 'of', 'hamster', 'tracheal', 'epithelial', 'cells.', 'These', 'substances', 'were', 'exposed', 'to', 'cristobalite,', 'and', 'their', 'response', 'with', 'regard', 'to', 'production', 'of', 'arachidonate', 'metabolites', 'assayed.', 'As', 'illustrated', 'in', 'Fig', '5,', 'these', 'monolayers', 'produced', 'increased', 'amounts', 'of', 'LTC', 'and', 'D,', 'and', 'of', 'PGE,', 'similar', 'to', 'organ', 'cultures.', 'Combined', 'with', 'additional', 'immunohistochemical', 'studies', '(see', 'PAF', 'studies', 'above)', 'it', 'appears', 'that', 'airway', 'epithelium', 'is', 'a', 'major', 'cell', 'type', 'in', 'the', 'respiratory', 'tract', 'producing', 'arachidonate', 'metabolites', 'with', 'potent', 'biological', 'activity,', 'in', 'response', 'to', 'a', 'variety', 'of', 'stimulatory', 'agents.', 'Specific', 'Aim', 'No.', '4:', 'To', 'define', 'the', 'comparative', 'biochemical', 'properties', 'of', 'the', 'stimulatory', 'components', 'in', 'cell-free', 'bacterial', 'culture', 'filtrates.', 'Culture', 'medium', 'filtrates', 'from', 'six', 'different', 'stimulatory', 'strains', 'of', 'Pseudomonas', 'aeruginosa', '(PV', '5,', '18,', '21,', '23,', '25,', '26)', 'were', 'edmcexiccnin’', '>', '100', 'times', 'by', 'ultrafiltration,', 'and', 'reconstituted', 'in', "Waymouth's", 'medium.', 'It', 'was', 'determined', 'strains', 'of', 'Pseudomonas', 'produced', 'enough', 'proteinase', 'in', 'their', 'cell-free', 'filtrates', 'to', 'explain', 'their', 'stimulation', 'of', 'mucin', 'secretion', 'by', 'tracheal', 'explants.', 'When', 'PV', '18', 'and', '23,', 'strongly', 'stimulatory', 'strains,', 'were', 'fractionated', 'on', 'a', 'CM', 'agarose', 'column,', 'fractions', 'containing', 'mucin-', 'stimulatory', 'activity', 'correlated', 'with', 'proteinase', 'activity', 'via', 'a', 'general-', 'ized', 'proteinase', 'assay', 'using', 'azocasein', 'as', 'a', 'substrate.', 'To', 'address', 'this', 'question', 'further,', 'several', 'commercial', 'preparations', 'of', 'r', ')', 'proteinases', 'were', 'examined', 'for', 'effects', 'on', 'mucin', 'secretion.', '"Pronase"', 'from', 'S,.', 'grisius,', 'trypsin,', 'collagenase', 'and', 'elastase', '(all', 'from', 'porcine', 'pancreas)', 'were', 'adjusted', 'in', 'concentration', 'to', 'an', 'equal', 'activity', 'toward', 'the', 'substrate,', ' ', ' ', '50163608']