21. Despite the advances, xenotransplant experts expect human organs to remain the preferred choice for patients. 22. Kessler said each institution that carries out xenotransplants would be required to store such samples indefinitely. 23. If the San Francisco researchers succeed against immense odds, demand for such xenotransplants could be huge. 24. So scientists are breeding pigs _ the most likely species for xenotransplants _ specially tested against infections. 25. _1964 : At the University of Mississippi, Dr . James Hardy attempts the first heart xenotransplant . 26. Another obstacle facing xenotransplants is that of the body s rejection of foreign objects by its immune system. 27. If nothing is found in the initial few xenotransplants , should monitoring continue for 500 or 1, 000? 28. Novartis, a Swiss-based pharmaceutical giant, reportedly plans to spent $ 1 billion on xenotransplant research. 29. The dispute has been a boon to animal rights activists seeking to persuade federal officials to stop xenotransplant research. 30. Pigs are especially likely sources for xenotransplants , chosen for the anatomical and physiological characteristics they share with humans.
