** FILE ** Rebecca Miller, an animal keeper at the National Zoo, brushes the teeth of Summer the seal. The seals get their teeth brushed every day with a regular toothbrush and seafood-flavored toothpaste. (Barbara L. Salisbury/The Washington Times)
**FILE** In this file photo originally made available by Advanced Cell Technology in 2006, a single cell is removed from a human embryo to be used in generating embryonic stem cells for scientific research.
Clustered Gram-negative Salmonella Typhimurium bacteria, the type linked to a salmonella outbreak that resulted in the recall of more than 1,500 foods, are shown under a magnification of 5000X in a colorized scanning photomicrograph. (AP Photo/Centers for Disease Control and Prevention, Janice Haney Carr) ** FILE **
** FILE ** Hanna Carter, 5, of Roanoke, Va., takes a dose of peanut protein from nurse practitioner Pam Steele at the Duke South Clinic at Duke University in Durham, N.C., on Tuesday, March 10, 2009. Hanna is being treated for peanut allergies. A handful of children once severely allergic to peanuts now can eat them without worry after scientists retrained the children's immune systems so they're allergy-free. (AP Photo/Gerry Broome)