Electron micrographs of reticulocytes cultured for 110 hours. Images of reticulocytes showing large intracellular vacuoles (v) containing cellular debris (left panel) or without cellular debris (center panel). A biconcave cell (right panel) without autophagic vacuoles contains faint, residual intracellular membranes (arrowhead) that are filled with hemoglobin. Magnification: left, × 7200; center, × 7500; right, × 6800.