WASHINGTON (AP) Researchers who developed some of the 64 embryonic stem cell lines that can be studied under federal grants say some of the lines they produced may prove unsuitable for further use and others are mired in patenting and licensing issues.
Scientists at Goteborg University in Sweden, which the National Institutes of Health says has 19 cell lines available, said Tuesday that only three are ready for research. The rest are still being processed and have uncertain futures.
''We don't know if all of them ... will become cell lines,'' said Professor Anders Lindahl of the Institute of Laboratory Medicine at Sahlegrenska University Hospital in Goteborg. A stem cell line is established when the cells become a self-replenishing colony, creating generation after generation of identical cells.
In an NIH announcement on Monday, federal officials said a worldwide search had located 64 embryonic stem colonies that met President Bush's criteria for being used in federally funded research. Under Bush's rules, the cell lines had to be in existence on Aug. 9 and had to come from surplus embryos from fertility clinics. The embryo parents also had to have consented, without compensation, to give up the embryos for research.
Lindahl said his laboratory was willing to let its cell lines be used in NIH research but noted: ''We have to be selective.''
He also said patent rights involving the cell lines are unsettled.
At Karolinska Institute in Stockholm, which NIH said had five cell lines, officials said the colonies are not scientifically ready for research.
''The cells are not validated,'' said Professor Lars Ahrlund-Richter. ''That is necessary in order to continue with clinical research.''