Light microscopy of nonparenchymal liver cells for the presence of oxidatively damaged red blood cells at 30 minutes after injection.

Cells were isolated as described in “Materials and methods.” Cytospins were fixed in acetone, stained with 3,3′-diaminobenzidine for endogenous peroxidase activity, and counterstained with hematoxylin. Red blood cells are dark brown. (A, B) Cells eluted at a flow rate of 26 mL/min (liver endothelial cells). (C, D) Cells eluted at a flow rate of 75 mL/min (Kupffer cells). Objective magnification ×40 (A, C); ×100 (B, D). The procedure was repeated 3 times and gave very similar results.