Expression of COX-1, -2, and MPO in HF and NF platelets. (A) Protein from washed platelets (3 μg protein) was separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) as described in “Patients, materials, and methods.” Membranes were probed using anti–COX-1, anti–COX-2, or antiactin, and immunoreactivity was revealed using anti–IgG-HRP secondary conjugates and ECL. Arrow shows bands corresponding to HF subject studied in Figure 5. (B) Relative density of COX-1 and actin in HF and NF samples shows no difference in COX-1 expression between subject groups. (C) Relative density of COX-2 and actin in HF and NF samples shows no difference in COX-2 expression between subject groups. Mean ± SEM, n = 4–5 separate patients. (D) Protein from washed platelets (3 μg protein) or human neutrophils (1.5 μg) was separated by SDS-PAGE as described in “Patients, materials, and methods” and probed using anti–human MPO and revealed using anti–IgG-HRP secondary antibody and ECL.