Oxidant-mediated lung epithelial cell tolerance: the role of intracellular glutathione and nuclear factor-kappaB 1 1Abbreviations: A549 cells, human alveolar epithelial type II cell line; AP-1, activator protein-1; BSO; dl-buthionine (SR)-sulfoximine; COPD, chronic obstructive pulmonary disease; DMEM, Dulbecco’s modified Eagle’s medium; DTT, dithiothreitol; GSHMEE, glutathione monoethyl ester; H2O2, hydrogen peroxide; IkB, inhibitory binding protein kB; LDH, lactic dehydrogenase; NAC, N-acetyl-l-cysteine; NF-kB, nuclear factor-kappa b; NPSH, non-protein sulphydryls; PKC, protein kinase C; and ROS, reactive oxygen species.