"In this case there was no sperm, no uterus, there was no vision for this to be a human being," said Bernard Siegel, director of the Genetics Policy Institute . "This is entirely something with the potential to create cures, understanding and treatment of medical conditions, and it's a real step in the right direction."
To create a clone, researchers take an egg from a woman and remove the nucleus. They replace it with a cell from the person to be cloned. They then use chemicals or zap it with electricity to kick-start cell division.
The Koreans had 242 eggs to work with, donated from 16 unpaid healthy women who underwent hormone treatment to stimulate their ovaries to produce more eggs than normal.
With so many eggs to work with, the researchers were able to tweak their process to optimize their methodology. First, instead of sucking the nucleus out with a pipette, which in other experiments sometimes damaged proteins that control cell division, the team nicked a small hole in the egg and gently squeezed the nucleus out.
In their fourth and most successful protocol, the researchers got 19 of 66 cloned eggs to develop into blastocysts -- the embryonic stage when it becomes possible to derive stem cells.
In the United States, President Bush announced in August 2001 that federally funded researchers would be prohibited from creating new embryonic stem cell lines, and would be allowed to use only the limited number of lines that already had been created. Researchers in the United States believe the mandate has severely limited progress in stem-cell research here.
"At the pace we're going we're never going to get there, because we don't have enough funding," Cibelli said. "The federal government will have to put up more money. These cells definitely have the potential to be treatments for many diseases."
The Korean researchers wrote that they could not rule out the possibility that their eggs might have begun spontaneously dividing and were not true embryos, a phenomenon called parthenogenesis. It's a type of reproduction found in many life forms, including flies, ants and lizards, but it doesn't create an embryo in mammals. It's not clear that stem cells from human parthenotes would be useful in therapies.
But genetic tests indicated the Koreans very likely had true embryos, not parthenotes.
"I have no doubt they have done somatic cell nuclear transfer," Cibelli said.
source: http://www.wired.com/news/medtech/0,1286,62254,00.html?tw=wn_tophead_1
