“…A TC 50 concentration of HEMA ranging from 10 μmol/L to 10 mmol/L has been demonstrated, mainly by mitochondrial dehydrogenase activity (MTT assay) and lactate dehydrogenase activity (LDH assay). It has been demonstrated that HEMA can induce genotoxicity (Schweikl et al, 2005) and apoptosis (Janke et al, 2003;Mantellini et al, 2003;Engelmann et al, 2004;Spagnuolo et al, 2004;Paranjpe et al, 2005); it interferes with the cell cycle and DNA synthesis (Hanks et al, 1991;Chang et al, 2005), increases the production of reactive oxygen species (ROS) (Chang et al, 2005;Spagnuolo et al, 2006), and induces a strong depletion of intracellular glutathione level even after very short times of exposure (Volk et al, 2006). Many of these data have shown the cytotoxic effects of HEMA at concentrations near the TC 50 value while very few studies have demonstrated HEMA influence in cells exposed to minor toxic concentrations (Costa et al, 1999;Bouillaguet et al, 2000) and the effect of these monomers on the expression of specific proteins (About et al, 2002).…”