Table 3 Important methodological issues of the experiments. For details see Geiser et al. [18].

Species

Adult male WKY/NCrl BR rats

Number

n = 5 for each group

Particles

Material

Titanium dioxide

Aerosol generation

Spark generator (Palas) in a pure argon plus 0.1% oxygen stream

Count median diameter (nm)

22 (SD 1.7)

Exposure

Inhalation of aerosol for 1 h

Fixation and tissue processing

Time point of fixation

1 h or 24 h after particle exposure

Fixation mode

Subsequent perfusion fixation with 2.5% buffered glutaraldehyde, 1% osmium tetroxide, 0.5% uranyl acetate

Tissue sampling

Systematic uniform random sampling

Material for light and electron microscopy

Semithin (toluidine staining) and ultrathin (uranyl acetate and lead citrate staining) sections