Table 1.

Levels of DNA damage and ROS production in PBMCs from 60 overweight elderly subjects after 5-h exposure to particles in urban street air or filtered air from the same site

	Particle-filtered air	Non-filtered air	Positive control
DNA damage
SB (lesions per 106 bp)	0.57±0.04	0.59±0.05	0.98±0.11
FPGss (lesions per 106 bp)	0.32±0.04	0.35±0.04	0.58±0.22
ROS production
Baseline (relative to THP-1)	0.66±0.05	0.56±0.05	NA
CB response (relative to THP-1)	1.26±0.16	1.16±0.18	NA

DNA damage was assessed as SB and formamidopyrimidine DNA glycosylase sensitive sites (FPGss) by means of the comet assay. PBMCs exposed to the photosensitiser Ro19-8022 and white light were included as positive control in all assay batches. ROS production was measured immediately after blood collection as DCFH-induced fluorescence directly (baseline) and the maximum fluorescence response above baseline induced by co-incubation with carbon black 14nm particles (CB) 0.625, 1.25, 2.5 and 5 µg/ml. The fluorescence was normalised to the DCFH-induced fluorescence obtained in THP-1 monocytic cells included in every set of measurements. The data are mean ± SEM. NA, not applicable.