Quantitative analysis of mixed cerebellar cultures after 24 h incubation with 50 μg/ml MNPs. All values are expressed as mean ± SD. (A) shows the number of microglia of control cultures and cells incubated with MNPs after 24 h. The percentage of microglia increased significant with MNP incubation. The number of astroglia, shown in (B), was not influenced by MNPs. No significant differences between both groups were found for oligodendroglia in (C). In (D), a comparison of the uptake for all cell types is shown. The number of cells which took up MNPs was highest for microglia, followed by astroglia, oligodendroglia and neurons.