A single gene, inserted into the apex of the heart, can convert normal cardiac muscle cells into those that control its electrical function, a study found.

The findings from laboratory experiments and work with guinea pigs are a step toward creating a "biological pacemaker" for humans with failing hearts, said Hee Cheol Cho, director of cellular electrophysiology at Cedars-Sinai Heart Institute in Los Angeles. Almost 10 percent of muscle cells exposed to the gene started spontaneously firing, behaving the same way as the rare pacemaker cells, the researchers said.

It will be years before doctors might be able to use the approach to treat people who currently rely on electronic pacemakers, Cho said. Additional studies in larger animals are needed to confirm the results and ensure the therapy is safe and lasting for humans. The findings appear in the journal Nature Biotechnology.


Six months after the federal government added cancer to the list of sicknesses covered by the $4.3 billion World Trade Center fund, a New York City health-department study has found no clear link between cancer and the dust, debris and fumes released by the two towers' wreckage.

The study was by far the largest to date. It examined 55,700 people, including rescue and recovery workers at the World Trade Center site, on barges or at the Staten Island landfill where debris was taken, in the nine months after Sept. 11, 2001, as well as residents of lower Manhattan, students, workers and passers-by exposed on the day of the terrorist attacks.

Overall, there was no increase in the cancer rate of those studied compared with that of the general population.