Corrections and clarifications.
In the news article "FDA puts the brakes on xenotransplants" by Rachel Nowak (5 May, p. 630) the description of the response of Columbia Presbyterian Medical Center in New York City to one of its investigators' proposal to test baboon-to-human heart transplants was incorrect. In fact, Columbia convened one panel of outside experts to advise its internal committees on the risks of xenotransplantation, and has since retained two outside experts as consultants to Robert Michler, the principle investigator for the xenotransplant trials. The institution also recommended that a group of experts on emerging infections be convened to examine the risk of viral transmission associated with xenotransplantation (Letters, 21 Apr., p. 349).