Effects of genistein and staurosporine on PMA and fMLP stimulation of human neutrophils. (A) Neutrophils (10⁶) were pretreated without or with increasing concentrations of staurosporine for 20 minutes before stimulation with 100 ng/mL PMA for 20 minutes (○) or 0.5 μmol/L fMLP for 5 minutes (•) and determination of SOD-inhibitable cytochrome c reduction. (B) Neutrophils (10⁶) were pretreated with or without 100 μmol/L genistein before stimulation with 100 ng/mL PMA for 20 minutes or 5 × 10^-7 mol/L fMLP for 5 minutes and determination of SOD-inhibitable cytochrome c reduction. Results are the average of duplicate determinations. Control absorbances were: (A) unstimulated cells, 0.336 ± 0.013; PMA-treated, 0.931 ± 0.005; fMLP-treated, 0.754 ± 0.008. (B) Unstimulated cells, 0.386 ± 0.005; PMA-treated, 0.606 ± 0.015; fMLP-treated 0.540 ± 0.007.