Although the current production of oxide nanoparticles may be modest, the wide range of proposed applications and forecasted growth in production has raised questions about the potential impact of these nanoparticles on the environment and human health. Iron oxide nanoparticles have been proposed for an increasing number of biomedical applications although in vitro toxicity depending on the particles coating has been evidenced. The aim of this study was to examine the potential in vitro cyto- and genotoxicity on human dermal fibroblasts of DMSA-coated maghemite nanoparticles (NmDMSA) as a function of well-defined physicochemical states. Well-stabilized NmDMSA produced weak cytotoxic and no genotoxic effects. This is attributed in part to the DMSA coating, which serves as a barrier for a direct contact between nano-oxide and fibroblasts, inhibiting a potential toxic effect.

The aims of the present study were to assess the occupational risk of welders using analysis of metals in biological fluids, DNA damage evaluation by complementary genotoxic endpoints and the incidence of polymorphisms in DNA repair genes. A biomonitoring study was conducted that included biometrology (blood and urinary concentrations of aluminium, cadmium, chromium, cobalt, lead, manganese, nickel, zinc by ICP-MS), comet and cytokinesis-block micronucleus assays in peripheral lymphocytes and genetic polymorphisms of XRCC1 (p.Arg399Gln) and XRCC3 (p.Thr241Met). This study included 60 male welders divided into two groups: group 1 working without any collective protection device and group 2 equipped with smoke extraction systems. A control group (n = 30) was also included in the study. Higher chromium, lead and nickel blood and urinary concentrations were detected in the two groups of welders compared to controls. Statistically differences between welders of group 1 and group 2 were found for blood concentration of cobalt and urinary concentrations of aluminium, chromium, lead and nickel. The alkaline comet assay revealed that welders had a significant increase of OTMchi2 distribution at the end of a work week compared to the beginning; a significant induction of DNA strand breaks at the end of the week was observed in 20 welders out of 30. The cytokinesis-block micronucleus assay showed that welders of group 1 had a higher frequency of chromosomal damage than controls. The XRCC1 variant allele coding Gln amino acid at position 399 was found to be associated with a higher number of DNA breaks as revealed by the comet assay. Increased metal concentrations in biological fluids, DNA breaks and chromosomal damage in lymphocytes emphasized the need to develop safety programmes for welders.

Complementary DNA encoding the human CYR61 protein was isolated from human embryonic tissues and mapped to chromosome 1p22-p31. We show that CYR61 encodes a 381 amino acid protein rich in cysteine and proline residues that is strongly conserved with the mouse homologue. Sequence analysis reveals the presence of several distinct protein domains which confer a mosaic structure to this protein and makes human CYR61 a member of a recently described growth regulator family that includes several proto-oncogene products. From our results we hypothesize that this new immediate early gene may play a role in cell commitment during embryogenesis and more generally in the control of cell proliferation.