title: Methylene blue decreases the functional activity of alpha-1-protease inhibitor in bronchoalveolar lavage.
abstract: Methylene blue, used as an external marker for bronchoalveolar lavage (BAL) in a concentration of 1 microgram/ml, reduced the functional activity of BAL alpha 1-protease inhibitor (alpha 1-PI) in 2 healing nonsmokers who each had 2 BAL done, one with and the other without methylene blue. Inactivation of alpha 1-PI by methylene blue was confirmed by in vitro experiments on diluted serum and concentrated BAL incubated with methylene blue. Inactivation of alpha 1-PI is likely due to its oxidation by methylene blue, as suggested by the in vitro protective effect of dithiothreitol, a reducing agent. These observations indicate a need for caution when considering the use of methylene blue as an external marker for bronchoalveolar lavage.
mesh_terms: D001798:Blood Proteins / Q000037:antagonists & inhibitors*; D004229:Dithiothreitol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D008751:Methylene Blue / Q000494:pharmacology*; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism*; D007507:Therapeutic Irrigation; D000515:alpha 1-Antitrypsin
chemical_list: D001798:Blood Proteins; D000515:alpha 1-Antitrypsin; D008751:Methylene Blue; D004229:Dithiothreitol