Stem Cell Differentiation (image) Gladstone Institutes Caption This shows a group of embryonic stem cells currently being transformed into beating heart muscle cells, or cardiomyocytes in a petri dish. Credit Jeff Alexander Usage Restrictions Please contact Gladstone Press Relations for reprint permissions. 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.