51.   Cocaine greatly enhanced replication of the virus and increased the number of human cells it infected and killed.

52.   Colon cells, according to the report, never pull that magic trigger that initiates the planned obsolescence that afflicts other human cells.

53.   Could baboon cells teach human cells how to fight the virus?

54.   Companies are testing their libraries of compounds on human cells and tissues in automated labs that can process thousands of tests in a day.

55.   Critics rightly note that scientists have not yet been able to explain how natural selection could produce the enormously complex machinery inside a human cell, for example.

56.   Dasgupta said the yeast molecule should be completely benign to living human cells.

57.   Could you put the nucleus of a human cell into a sheep egg?

58.   Crossing an explosive ethical boundary, Advanced Cell Technology in Worcester has started an unprecedented program to clone and harvest human cells, the company president said Thursday.

59.   DNA, or deoxyribinucleic acid, contains the genetic codes that distinguish each person from all others and is contained in each human cell.

60.   Despite a flurry of international interest, the company has revealed little about its plans to grow genetically matched human cells.