Figure 1

A) Effect of LPS, ultrafine P90, and fine TiO ₂ on CYP1B1 mRNA levels in CD14++ monocytes. Cells were purified from PBMC of healthy donors by MACS separation. CD14++ cells remained untreated (none) or were stimulated with LPS (10 ng/ml), with particle-mix of ultrafine P90 and fine TiO₂ (each with 32 μg/ml) or with each particle separately for 3 h. Cells were lysed and mRNA levels were determined by RT-PCR. Data were normalized to levels of the house keeping gene α-enolase. (n = 3 incubations from different donors, mean ± S.D.; * p < 0.05 compared to untreated controls). B) Down-regulation of CYP1A1 mRNA in monocytes. CD14++ cells remained untreated (none) or were stimulated with LPS (10 ng/ml), with particle-mix of ultrafine P90 and fine TiO₂ (each with 32 μg/ml) or with each particle separately for 3 h. Cells were lysed and mRNA levels were determined by RT-PCR. (n = 3 incubations from different donors, mean ± S.D.; * p < 0.05 compared to untreated controls).