Figure 2A: Hepatocyte ultrastructure. Panel A: Untreated tissue at 0 h, showing a hepatocyte with preserved architecture. Note hepatocyte nucleus (N), numerous intact mitochondria (m) and rER; magnification =98,000. Untreated tissue at 4 h, showing a hepatocyte with minimal distension of the mitochondria (m) and minimal disintegration of the rER; magnification =7,000. Tissue treated with 2.5 μM sorafenibat 4 h, showing a hepatocyte with mild distension of the mitochondria (arrow) with amorphous densities. Early loss of integrity of rER was also noted; magnification =7,000. Tissue treated with 5.0 μM regorafenib at 4 h, showing a hepatocyte with mild distension of the mitochondria (arrows) with amorphous densities. The rER changes were more evident; magnification =7,000.