The Justice Department is asking an appeals court in Washington to overturn a ban on federal money for stem-cell research involving human embryos.
The White House and scientists said Monday's court ruling was broader than first thought because it would prohibit even the more restricted stem-cell research allowed for the past decade under President George W. Bush's rules.
The Justice Department said an appeal is expected this week of the federal judge's preliminary injunction that disrupted an entire field of science.
Judge Royce Lamberth on Monday threw the research community into disarray when he said a federal law invalidated Obama administration guidelines on human-stem-cell research. He concluded that two researchers challenging the Obama stem-cell policy stood a good chance of success as the case moved ahead in the courts.
The judge said any scientific projects using human embryos required their destruction, which flouts a longstanding federal law.
That law, called the Dickey-Wicker amendment, was written several years before scientists began growing batches, or lines, of stem cells culled from embryos, and Obama and two previous administrations -- Bush and Clinton -- had made a distinction between it and stem-cell research.
That initial ruling won't stop all the work that scientists call critical to finding new therapies for devastating diseases. The National Institutes of Health told anxious researchers late Tuesday that if they've already received money this year -- $131 million in total -- they can keep doing their stem-cell experiments.
But 22 projects that were due to get yearly checks in September, $54 million worth, "will be stopped in their tracks," said NIH Director Francis Collins -- meaning a waste of the millions those scientists already have spent unless they can find private dollars to keep the stem cells alive. Dozens more proposals won't get a hearing pending the court case's conclusion.
"This decision has just poured sand into the engine of discovery," Collins said.
Scientists, who have been struggling to understand the implications of a funding stoppage, say the ruling could set back efforts to develop new treatments for dozens of diseases using stem cells from donated human embryos.
Monday's ruling will "drive the best scientific minds into work less likely to yield treatments," said Sean Tipton of the American Society for Reproductive Medicine. "It will be incredibly disruptive."
However, the ruling drew praise from the Alliance Defense Fund, a group of Christian attorneys who helped with the lawsuit filed by two researchers against the administration rules.
"The American people should not be forced to pay for experiments -- prohibited by federal law -- that destroy human life. The court is simply enforcing an existing law passed by Congress that prevents Americans from paying another penny for needless research on human embryos," said Steven H. Aden, the group's senior legal counsel.
President Obama, who last year ordered an expansion of stem-cell research, "put forward stringent ethical guidelines, and he thinks that his policy's the right one," deputy press secretary Bill Burton told reporters Tuesday.
Asked if it might take new legislation from Congress to counter the ruling from Lamberth, Burton said the administration was exploring all avenues "to make sure that we can continue to do this critical lifesaving research."
How quickly any appeal could go through may determine how much is permanently lost.
"These cells are notoriously finicky, and you have to take care of them every day. You can't just lock up a lab and walk away for two weeks and come back and everything's fine," said Dr. Jonathan Moreno, a medical ethicist at the University of Pennsylvania, where scientists were scrambling to tell which projects had to halt and which didn't.
If it takes "months to settle the legal wrangling, then we will just end our work," said Dr. Sean Morrison, director of the University of Michigan Center for Stem Cell Biology, whose lab is studying embryonic stem cells in hopes of reversing a serious intestinal birth defect.
Already, one leading stem-cell researcher had shifted gears: At Children's Hospital Boston, Harvard researcher Dr. George Daley told his team to assume they couldn't use any of millions of dollars in government grant money to nurture the embryonic stem cells growing in his lab but must keep those cells alive by using equipment bought with private funds.
Some Democrats said Tuesday they would try the legislation again, and Sen. Tom Harkin (D-IA) pledged a hearing on the court ruling as soon as Congress returns next month.
NPR's Carrie Johnson contributed to this report, which also includes material from The Associated Press