Figure 1.

Superoxide anion production by monocytes after induction with phorbol myristate acetate (PMA; 100 nM) for 15 min. From healthy controls (n = 10), patients with systemic sclerosis (SSc) after disruption of calcium-channel blocker treatment (n = 12) (baseline) and patients with SSc after 14 days of treatment with 60 mg/day nifedipine (NIF) (n = 12) (a), from healthy donors (n = 5) treated with or without various concentrations of nifedipine for 30 min before stimulation with PMA (b) and from healthy donors treated with or without calcium-channel blockers (10 µM) before stimulation with PMA (c). *P < 0.05; **P < 0.01 relative to controls.