31.   Transplanting animal organs into humans offers such promise that nations should work together to overcome scientific and ethical problems, experts told a U.N.-sponsored meeting Thursday.

32.   Transplanting organs from one species to another, called xenotransplantation, generally has not worked because the organ is rejected by the immune system of the host.

33.   Transplanting animal organs into humans offers such promise that nations should work together to overcome scientific and ethical problems, experts said at a U.N.-sponsored meeting.

34.   Until a defrosted organ is transplanted into a human and functions, they say, celebration is premature.

35.   He also dismissed warnings from American and British virologists that a lethal pig virus could spread to humans if pig organs were transplanted on them.

36.   I was afraid but now I tell people that organs can be transplanted.

37.   Transplanting animal organs into humans has failed to work in the past, but Platt and his colleagues have used genetic manipulation to improve their chances for success.

38.   Previous attempts to transplant organs between species have failed, but doctors believe this effort may succeed because immunological responses are weaker in the brain.

39.   Researchers, who were experimenting with transplanting pig organs to monkeys, first tried using immunosuppressive drugs, but found them effective only for a few weeks.

40.   The latter trip resulted in a documentary on the alleged Chinese practice of transplanting organs from executed prisoners into cash-paying foreigners or well-connected Chinese.