Cells Following a Chemical Trail (video) Johns Hopkins Medicine Share Print E-Mail Loading video... Caption In this video, lab-grown human leukemia cells move toward a pipette tip holding an attractive chemical. Credit Yulia Artemenko/Johns Hopkins Medicine Usage Restrictions Permission required. 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.