Histological analysis of maternal liver after exposure to PEG-SWCNTs. A. Liver sections from dams exposed to vehicle only (a, b), 30 μg (c) or to three repeated administrations of 10 μg each (d) were stained with Hematoxylin and Eosin. In the liver from animals that received three administrations, areas of extramedullary hematopoiesis were in some cases evidenced (d). (e) Magnification of the boxed area in d shows the presence of monocyte and granulocyte like cells (arrows). B. Histograms show no differences in the number of apoptotic cells in all liver samples analyzed.