Singlet oxygen plays a key role in the toxicity and DNA damage caused by nanometric TiO2 in human keratinocytes.

Nanometric TiO2 has been reported to be cytotoxic and genotoxic in different in vitro models when activated by UV light. However, a clear picture of the species mediating the observed toxic effects is still missing. Here, a nanometric TiO2 powder has been modified at the surface to completely inhibit its photo-catalytic activity and to inhibit the generation of all reactive species except for singlet oxygen.

Pyrogenic activity of air to characterize bioaerosol exposure in public buildings: a pilot study.

Aims: The aim of our study was to investigate indoor air quality (IAQ) by comparing pyrogen concentration and microbiological contamination in offices in public buildings.

Methods And Results: Air samples were collected during cold and warm seasons in 39 offices in four European cities. Pyrogens were measured by the in vitro pyrogen test (IPT), moulds and bacteria by classical microbiology.

Effects of toluene and benzene air mixtures on human lung cells (A549).

Human epithelial lung cells (A549) were exposed to toluene and benzene in the air as individual compounds and mixtures at concentrations of about 0.25ppmv in a specifically adapted fumigation device. Possible early toxicological effects at cellular level have been determined by lactate dehydrogenase (LDH), glutathione redox status (GSH) and comet assay.

An optimized method for in vitro exposure of human derived lung cells to volatile chemicals.

Volatile organic compounds (VOCs) such as benzene and toluene, and low molecular weight carbonyls like formaldehyde belong to the main air pollutants found in indoor environments. They are suspected to induce acute and chronic adverse health effects like asthma, allergic and cardiovascular diseases, and strongly affect well-being. Our aim was to further develop and optimize an in vitro method to study the exposure of epithelial tumour lung cells (A549) by using a commercial exposure chamber (CULTEX) to assess the biological effects of VOCs and carbonyl compounds at low concentration levels.

Meeting report: Validation of toxicogenomics-based test systems: ECVAM-ICCVAM/NICEATM considerations for regulatory use.

This is the report of the first workshop "Validation of Toxicogenomics-Based Test Systems" held 11-12 December 2003 in Ispra, Italy. The workshop was hosted by the European Centre for the Validation of Alternative Methods (ECVAM) and organized jointly by ECVAM, the U.S.