ST. PETERSBURG TIMES

President Bush's decision to allow taxpayer funding of limited embryonic stem cell research likely will accelerate the search for potential cures for a variety of debilitating diseases, from Alzheimer's to Parkinson's to diabetes to stroke.

But the initial effects of Bush's decision will be more subtle, as this previously unfunded arm of stem cell science gears up, and scientists digest the restrictions Bush attached.

The National Institutes of Health has never paid for embryonic stem cell research, despite approval for it during the Clinton administration, and most scientists who are studying stem cells from other sources aren't likely to switch suddenly to embryos.

Plus, only 20 to 30 people boast the credentials and experience to qualify for the NIH funds, experts estimate.

"People who do have that expertise and who are working on other issues … are not all of a sudden going to drop what they're doing," said Dr. Dennis Steindler, professor of neuroscience at the University of Florida's McKnight Brain Institute, who works with stem cells found in the brain.

But allowing NIH funding will ensure public access and scrutiny of research into cells taken from human embryos. This research is now dominated by private companies and a scant handful of university medical centers, such as Johns Hopkins, that have secured private grants.

"You don't want to see this kind of research remain in private hands, because these companies don't always behave ethically," said Dr. Glenn McGee, editor-in-chief of the American Journal of Bioethics and a professor of bioethics at the University of Pennsylvania.

Bush's decision will allow federal funding only for embryonic stem cells that have already been propagated by private research. They can be manipulated to produce new generations of cells. McGee said much of the available federal funding, perhaps as much as 50 percent, will have to be used to buy the rights to those cell lines and other patents companies hold on them.

Dr. Juan Sanchez-Ramos, a professor of neurology at the University of South Florida who experiments with stem cells from bone marrow and umbilical cord blood, said allowing NIH funding for embryonic research is key to learning what works best and may draw more scientists into the field.

"This is the very beginning of this research. We don't know how useful (embryonic cells) will be, we don't even know if they'll be the best," he said. "The only way we're going to find out is to allow regulated research to go on, and to make the research public."

The promise of stem cells is dizzying: In experiments, the cells have become new neurons to replace cells damaged by stroke, Parkinson's and Alzheimer's. New insulin-producing cells to cure diabetes. New heart cells to cure cardiovascular disease.

The key to these treatments is a delicate process called transdifferentiation, by which a stem cell — essentially a blank slate — is chemically coaxed into becoming a specific type of cell. One reason embryonic stem cells are so important is because they appear more willing to be transformed than stem cells from other sources. They also appear more plentiful and hardy.

Last month, the NIH issued a report saying that while all stem cells were promising, embryonic cells appeared especially so. Clearly, technology to convert one cell type into another to repair damage would be the ultimate human tool kit.

Although Clinton cleared the way for federal funding for embryonic research, the process of developing guidelines outlasted his term. Bush put the funding on hold before the March 15 deadline for funding applications. The NIH received just two.

Most stem cell research in the United States involves so-called adult stem cells found in the umbilical cord blood of newborn babies, the bone marrow, the brain, liver and other organs. NIH support of that research amounted to $256 million last year.