Biliary hyperplasia in ANIT-exposed mice. WT, Fibγ^390-396A, and FXIII^−/− mice were fed a control diet (AIN-93M) or an identical diet containing 0.025% ANIT for 4 weeks. Representative photomicrographs (×200) show liver sections stained for CK-19 (brown) in ANIT-exposed: (A) Fibγ^390-396A mice, (C) FXIII^−/− mice, and (A,C) corresponding WT mice. Arrows indicate areas of biliary hyperplasia. Asterisks indicate focal hepatocellular necrosis (ie, bile infarcts). (B,D) CK-19 staining was quantified as described in “Methods.” Data are expressed as mean + SEM; n = 4 to 16 mice per group. *P < .05 vs ANIT-exposed WT mice.