Liver pathology of Gimap5^−/− mice. (A) In situ appearance of the liver in a 7-week-old Gimap5^−/− mouse. The gallbladder (brown, lower left) appears normal. Image was acquired with a Nikon Coolpix digital camera. (B,C) Histologic sections (periodic acid Schiff [PAS] stain). Large areas appear necrotic (pale PAS stain, swollen hepatocytes with finely granular cytoplasm, sparse nuclear staining) but are largely devoid of mononuclear cells. (C) Other areas of the liver are characterized by massive, centrilobular, and periportal accumulation of mononuclear cells (blue nuclear stain, original magnification ×100). Bars represent 100 μm. (D) Liver histology of a 3-week-old gimap5^−/− mouse (Trichome stain, original magnification ×200). Bar represents 100 μm. External appearance and histology of the liver parenchyma appear normal; the Gimap5^−/− liver contains a large number of hematopoietic foci (→; inset shows high power view; original magnification ×400). Bar represents 10 μm. (B-D) Images were acquired on a Nikon Eclipse E600 microscope with 10×, 20×, and 40× PlanFluor objectives and a SPOT Insight 11.2 color mosaic digital camera with Spot software version 4.1 (Diagnostic Instruments, Sterling Heights, MI). (E) TUNEL stain of liver shown in panel B; areas of TUNEL positivity correlate with the pale-staining areas in PAS-stained sections. (F) DNA fragmentation is not detected in young Gimap5^−/− livers shown in panel D. (E,F) TUNEL staining with fluorescein-labeled deoxyuridine triphosphate (dUTP) was recorded in the FITC channel.