Figure 3: Oxidative stress in As-exposed subjects. Flow cytometric measurement of ROS generation in peripheral blood leukocytes (a and b) and airway cells in sputum (c and d) shows increased ROS generation in sputum but reduced in blood leukocytes of As-exposed women (green line). A total of 10,000 events were acquired for each sample, and the mean fluorescence intensities were 56.4 ± 24.6 in exposed vs. 662.4 ± 117.5 in control, p<0.001 for blood leukocytes and 233.2 ± 44.7 in exposed vs. 43.7 ± 17.8 in control, p<0.001 for sputum cells. The inducible nitric oxide synthase activity was also detected in a greater percentage of sputum neutrophils of As-exposed women (f) compared with control (e), Immunocytochemical staining counterstained with hematoxylin, original magnification 1000x.