The VBLOC, by EnteroMedics in St. Paul, Minnesota, is a small abdominal-cavity implant that blocks vagus-nerve signals by zapping the nerve with electric pulses. A similar implant, the Abiliti by IntraPace, based in Mountain View, California, sends additional signals instead of stopping them. The device electrically stimulates the stomach wall, which is thought to send a "full" feeling to the brain. Patients in VBLOC and Abiliti trials have shed, respectively, up to 30 percent and 38 percent of their body weight. Both devices could be on the U.S. market by 2014.