Old and unattracted

lectrical fields (EFs) present at wound sites can orient and promote cell divisions, according to work by Bing Song, Colin McCaig, and colleagues (University of Aberdeen, Aberdeen, Scotland). The EFs arise because channels shuttle ions between the tear fluid on the outside of the eye and the extracellular fluid bathing the underlying tissue layers. Before the surface of an eye is damaged, channels actively pump out Cl ions and pump in Na and K ions. That gradient is destroyed by wounding, leaving an EF in the extracellular fluid that runs from positive (far from the wound) to neutral or less positive (at the wound site). The authors directly measured the decline of this EF near wound sites. Various drugs changed the EF by activating or inhibiting the ion pumps. The authors then provided the first in vivo correlation of EF magnitude with cellular behavior. Proximity to the wound E