Figure 5: Graph shows percentage of total number of added monocytes that migrated across monolayers of brain endothelium after SPIO labeling at a concentration of 1.0 mg Fe/mL. Freshly isolated monocytes (Ctrl) and vehicle-treated cells served as negative controls. Monocytes stimulated with lipopolysaccharide (LPS) for 24 hours served as a positive control. Data are presented as mean ± standard error of the mean. * = P < .05 versus freshly isolated monocytes.