Cardiac Muscle at Day 15 (image) Emory Health Sciences Share Print E-Mail Caption This is mouse cardiac muscle at day 15. Red staining comes from Aurora B kinase, a sign of mitosis [cell division]. In similar tissue slices from days 14 and 16, none of the cells are red. Credit From Naqvi et al, Cell (2014) Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.