EM of cardiac tissue from 18-day-old MHC-ACS mice. Ultra-thin sections of fixed ventricular tissue from 18-day-old MHC-ACS O7 animals were examined by transmission EM. Images are shown at ×7,500 (a; bar, 1 μm), and at ×15,000 (b; bar, 0.5 μm). Numerous lipid droplets (L) are observed in ventricular myocytes. Some droplets at this stage are surrounded by multiple concentric layers of membrane (arrow).