Many-armed magnets reveal stem cells

In the next few years, doctors may start injecting people with human embryonic stem cells to treat maladies such as multiple sclerosis and diabetes. However, tracking those cells, which can differentiate into any cell type in the body, is a challenge. In animal studies (SN: 9/1/01, p. 143: Stem cell research marches on), researchers dissect their subjects to find out where such cells go and how they develop.