11.   Asked why a healthy transplanted heart would need to grow new cells, Anversa said the new heart was not necessarily so healthy.

12.   Bones are constantly being renovated, with cells called osteoclasts breaking down old bone cells, and new cells being built.

13.   A second development was the discovery that adult brains continue to produce new cells, overturning conventional wisdom that brain cells are not replenished.

14.   A year later, they discovered that new cells were migrating to the olfactory bulb, where smells are decoded.

15.   Advanced Cell Technology, a Maryland company, is hoping someday to rejuvenate human hearts, brains, immune systems and joints with spanking new cells.

16.   But a senior administration official said Bush was firm in his decision to close the door on federal funding for any new cell lines.

17.   But researchers still did not believe that new cells were created in human brains, Raastad said.

18.   But, Nottebohm said, the problem might be that scar tissue is interfering with the reconnection of circuits in the brain, not that new cells cannot grow.

19.   Cell phone companies have been unable to build enough new cell towers or squeeze the capacity they need out of existing ones.

20.   Conversely, in diseases of aging, activating telomerase could be beneficial by prompting the growth of new cells.