Monday, January 14, 2008
Astronomers Describe Violent Universe
The deeper astronomers gaze into the cosmos, the more they find it's a bizarre and violent universe. The research findings from this week's annual meeting of U.S. astronomers range from blue orphaned baby stars to menacing "rogue" black holes that roam our galaxy, devouring any planets unlucky enough to be within their limited reach.
"It's an odd universe we live in," said Vanderbilt University astronomer Kelly Holley-Bockelmann. She presented her theory on rogue black holes at the American Astronomical Society's meeting in Austin, Texas, earlier this week.
It should be noted that she's not worried and you shouldn't be either. The odds of one of these black holes swallowing up Earth or the sun or wreaking other havoc is somewhere around 1 in 10 quadrillion in any given year.
This is the glory of the universe," added J. Craig Wheeler, president of the astronomy association. "What is odd and what is normal is changing."
Just five years ago, astronomers were gazing at a few thousand galaxies where stars formed in a bizarre and violent manner. Now the number is in the millions, thanks to more powerful telescopes and supercomputers to crunch the crucial numbers streaming in from space, said Wheeler, a University of Texas astronomer.
Scientists are finding that not only are they improving their understanding of the basic questions of the universe -- such as how did it all start and where is it all going -- they also keep stumbling upon unexpected, hard-to-explain cosmic quirks and the potential, but comfortably distant, dangers.
Much of what they keep finding plays out like a stellar version of a violent Quentin Tarantino movie. The violence surrounds and approaches Earth, even though our planet is safe and "in a pretty quiet neighborhood," said Wheeler, author of the book "Cosmic Catastrophes."
One example is an approaching gas cloud discussed at the meeting Friday. The cloud has a mass 1 million times that of the sun. It is 47 quadrillion miles away. But it's heading toward our Milky Way galaxy at 150 miles per second. And when it hits, there will be fireworks that form new stars and "really light up the neighborhood," said astronomer Jay Lockman at the National Radio Astronomy Observatory in West Virginia.
But don't worry. It will hit a part of the Milky Way far from Earth and the biggest collision will be 40 million years in the future.
The giant cloud has been known for more than 40 years, but only now have scientists realized how fast it's moving. So fast, Lockman said, that "we can see it sort of plowing up a wave of galactic material in front of it."
When astronomers this week unveiled a giant map of mysterious dark matter in a supercluster of galaxies, they explained that the violence of the cramped-together galaxies is so great that there is now an accepted vocabulary for various types of cosmic brutal behavior.
The gravitational force between the clashing galaxies can cause "slow strangulation," in which crucial gas is gradually removed from the victim galaxy. "Stripping" is a more violent process in which the larger galaxy rips gas from the smaller one. And then there's "harassment," which is a quick fly-by encounter, said astronomer Meghan Gray of the University of Nottingham in the United Kingdom.
Gray's presentation essentially showed the victims of galaxy-on-galaxy violence. She and her colleagues are trying to figure out the how the dirty deeds were done.
In the past few days, scientists have unveiled plenty to ooh and aah over:
* Photos of "blue blobs" that astronomers figure are orphaned baby stars. They're called orphans because they were "born in the middle of nowhere" instead of within gas clouds, said Catholic University of America astronomer Duilia F. de Mello.
* A strange quadruplet of four hugging stars, which may eventually help astronomers understand better how stars form.
* A young star surrounded by dust, that may eventually become a planet. It's nicknamed "the moth," because the interaction of star and dust are shaped like one.
* A spiral galaxy with two pairs of arms spinning in opposite directions, like a double pinwheel. It defies what astronomers believe should happen. It is akin to one of those spinning-armed flamingo lawn ornaments, said astronomer Gene Byrd of the University of Alabama.
* The equivalent of post-menopausal stars giving unlikely birth to new planets. Most planets form soon after a sun, but astronomers found two older stars, one at least 400 million years old, with new planets.
"Intellectually and spiritually, if I can use that word with a lower case 's,' it's awe-inspiring," Wheeler said. "It's a great universe."
The Violent Universe
It s a bizarre and violent universe
The deeper astronomers gaze into the cosmos, the more they find it's a bizarre and violent universe. The research findings from this week's annual meeting of U.S. astronomers range from blue orphaned baby stars to menacing "rogue" black holes that roam our galaxy, devouring any planets unlucky enough to be within their limited reach.
Researchers Restart Rat Heart
Researchers seeking new treatments for heart disease managed to grow a rat heart in the lab and start it beating.
"While it still sounds like science fiction, we've hopefully opened a new door in the notion that we can build these tissues and one day provide options for patients with end-stage disease," said Dr. Doris Taylor, director of the Center for Cardiovascular Repair at the University of Minnesota. "We're not there yet, but at least now we have another tool in our tool belt."
Taylor led the team whose research appeared in Sunday's online edition of the journal Nature Medicine.
Scientists have worked for years for ways to grow body parts. Many efforts have focused on heart valves as an alternative to the plastic or animal valves that wear out after being implanted in humans.
An estimated 5 million people live with heart failure and about 550,000 new cases are diagnosed each year in the United States. Approximately 50,000 die annually waiting for a heart donor.
Taylor said in a telephone interview that her team began by trying to determine if it were possible to transplant rat heart cells. They took the hearts from eight newborn rats and removed all the cells. Left behind was a gelatin-like matrix shaped like a heart and containing conduits where the blood vessels had been. Scientists then injected cells back into this scaffold -- muscle cells and endothelial cells, which line blood vessels.
The muscle cells covered the matrix walls and lined up together, while the endothelial cells found their way inside to coat the blood vessels, she said. Then the hearts were stimulated electrically.
"By two days we saw tiny, microscopic contractions, and by seven to eight days there were contractions large enough to see with the naked eye," she said. The tiny hearts could pump liquid at about one-fourth the rate of a normal fetal rat's heart.
"Obviously we have a long way to go," Taylor said. But the long-term hope, she said, is that a similar process could work with either human hearts from cadavers or pig hearts, with their cells stripped off and replaced by cells from the person needing a heart transplant to avoid rejection.
The next step is to take a pig heart, strip away the cells and repopulate it with cells from a pig to see if it will work in the larger heart.
Dr. John Mayer Jr., a heart specialist and researcher at Children's Hospital in Boston, said the report was an "important paper that advances the ball down the road." But, he added, "It's pretty long road."
Mayer, who was not part of Taylor's research team, noted that this was done in a small animal and it remains to be seen whether the same can be done in larger ones. He also wondered whether blood would flow freely, without clotting, through the reconstructed blood vessels.
"I think this is an important contribution, with more work to be done," Mayer said in a telephone interview.
In her research paper, Taylor also reports that the researchers are working on reseeding cells into other organs, including lungs, liver and kidneys.
The research was funded by the University of Minnesota and the Medtronic Foundation, the charitable arm of a medical company that makes heart devices such as stents and defibrillators.
New treatment for heart attacks
A team led by scientists at The Scripps Research Institute has developed a potential new treatment for heart attacks. The therapy inhibits fluid leakage from cardiac blood vessels following a heart attack and thereby significantly prevents long-term heart damage and improves survival.
"Immediately following a heart attack, blood vessels near the site of injury become leaky, causing fluid accumulation in the healthy area of the heart surrounding the injured site," says Immunology Professor David A. Cheresh, Ph.D., who led the research with postdoctoral fellow Sara Weis, Ph.D at The Scripps Research Institute. This permeability response is devastating to normal heart tissue.
"Until now," continues Cheresh, "nobody has realized the extent to which this leak response damages heart tissue and causes long-term tissue injury. We discovered a way to block this process and thus save heart tissue from irreversible damage."
Using laboratory models that are designed to mimic the pathology of heart attacks in humans, Cheresh, Weis, and their colleagues found that a single dose of a compound designed to block this fluid leakage (which is called edema) can, even if given as late as six hours after the event, drastically reduce tissue injury and increase long-term survival following a heart attack.
A biopharmaceutical company, TargeGen Inc. in San Diego, is finalizing preclinical studies to translate these initial research findings into practical human therapies. Using extensive preclinical models that mirror human heart attacks, TargeGen scientists report that 40 to 60 percent reductions in infarct (tissue injury) size with a small molecule drug that inhibits vascular leak and edema. Based on the encouraging preclinical efficacy and safety studies, TargeGen plans to initiate a combined Phase I/II human clinical trial in the second half of 2004 for patients undergoing an acute heart attack.
In addition to Cheresh and Weis, the team included scientists from St. Elizabeth's Medical Center at Tufts University School of Medicine in Boston, Massachusetts; the Department of Radiology at Beth Israel Deaconess Medical Center in Boston; and the private company TargeGen, Inc. of San Diego, California.
Netflix offers all you can watch online
Unlimited streaming plan aimed at pre-empting Apple's video play
Girding for a potential threat from Apple, online DVD rental service Netflix is lifting its limits on how long most subscribers can watch movies and television shows over high-speed Internet connections.
The Associated Press has learned the change will become effective Monday, on the eve of Apple's widely anticipated move into the movie rental industry. Although Apple hasn't confirmed anything yet, Chief Executive Steve Jobs is expected to make it official during a presentation Tuesday in San Francisco.
Netflix is gearing up for the increased competition by expanding a year-old feature that streams movies over the Internet instead of making customers wait for their online rental requests to be delivered through the mail.
Until now, Netflix restricted how long its more than 7 million subscribers could use the streaming service each month, based on how much they pay to rent DVDs.
For instance, under a popular plan that charges $16.99 per month to rent up to three DVDs at a time, Netflix customers could watch as many as 17 hours of entertainment each month on the streaming service, dubbed "Watch Instantly."
With Monday's change, virtually all Netflix subscribers will be able to stream as many movies and TV shows as they want from a library containing more than 6,000 titles. There will be no additional charge for the unlimited access.
Only the small portion of Netflix customers who pay $4.99 to rent up to two DVDs per month won't be provided unlimited access to the streaming service.
The unlimited streaming option figures to become more enticing later this year when LG Electronics Inc. will begin selling a set-top box that will deliver the content to TVs.
One-upping Apple ... at a cost
Removing the time constraints on its streamed entertainment could give Netflix an advantage over Apple's movie rental service. Apple will charge $3.99 for movies that can be downloaded and played for up to 24 hours, according to media reports citing people familiar with the company's rental plans.
Letting subscribers stream as much as they want could erode Netflix's profits because the Los Gatos-based company isn't raising its monthly rates even though its expenses may rise if increased usage drives up the licensing fees owed to studios.
Providing unlimited streaming access "fits within the parameters of our overall financial goals," Netflix spokesman Steve Swasey said. The impact of the change will likely be addressed when Netflix discusses its fourth-quarter earnings in a call scheduled for Jan. 23. The company had earned $51 million on revenue of $903 million through the first nine months of 2007.
DVD-by-mail still dominates
With more than 90,000 titles available in its DVD library, delivering movies through the mail is expected to remain Netflix's primary moneymaker for years to come.
Nevertheless, Netflix has spent about $40 million on the development of its streaming service during the past year.
The service still doesn't appeal to many Netflix subscribers because it requires watching the entertainment on a personal computer with a high-speed Internet connection.
Netflix hasn't specified how much content has been streamed since last summer, when management disclosed that more than 10 million movies and TV episodes had been watched through the service. The company says its streaming service has gained the most traction among younger subscribers more accustomed to watching movies on laptops.
Netflix is the largest online DVD rental service, offering flat rate rental-by-mail to customers in the United States. Established in 1998 and headquartered in Los Gatos, California, it has amassed a collection of 90,000 titles and over 6.7 million subscribers.  They have over 55 million discs and ship 1.6 million a day, on average.  Netflix previously claimed to spend about $300 million a year on postage. On February 25, 2007, Netflix announced the delivery of its billionth DVD.
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Stem cells created without destroying embryos
A government official says the technique would make such research eligible for federal funding.
Scientists reported Thursday that for the first time they have made human embryonic stem cells without destroying embryos, a development that the government's top stem cell official said would make the controversial research eligible for federal funding.
Story Landis, who chairs the National Institute of Health's stem cell task force, said that with certain safeguards, the new method appeared to comply with federal restrictions that have largely cut scientists off from the $28 billion the government spends on medical research each year.
Federal law prohibits the National Institutes of Health from paying for experiments that place human embryos at risk of injury or death, and spending on human embryonic stem cell research is restricted to projects involving a handful of cell lines that were created before August 2001.
Researchers at Advanced Cell Technology in Worcester, Mass., created four stem cell lines out of individual cells plucked from 3-day-old embryos, which continued to develop normally after the procedure. The method was described in the online edition of the journal Cell Stem Cell.
The removal of a single cell from a young embryo is done thousands of times a year in the U.S. by fertility laboratories to screen embryos for genetic diseases.
Dr. Robert Lanza, Advanced Cell Technology's chief scientific officer, said researchers could piggyback on the procedure by allowing the removed cell to divide in a laboratory dish. Then, with the consent of patients, one copy could be used for genetic screening and the other to make stem cells.
Under those circumstances, the research "should be permissible under the Bush policy," said Russell Korobkin, a stem cell expert at the UCLA School of Law. "The NIH should not decline to fund this."
Though the technique spares embryos, it still raises ethical concerns.
The Rev. Tadeusz Pacholczyk, an ethicist at the National Catholic Bioethics Center in Philadelphia, said that removing a single cell from an embryo turns it into "a starting source for harvestable raw materials, in a gesture that reduces young humans to commodities."
And because the single embryonic cell can be grown into stem cells, some scientists and ethicists wondered whether the cell itself has the potential to become a whole new embryo.
"It would be hard to rule out," said Martin Pera, director of the Center for Stem Cell and Regenerative Medicine at USC.
But for scientists who have struggled under federal restrictions, the technique has injected a sense of optimism that there may soon be a break in the political logjam that scientists blame for stalling progress in the field.
After all, the idea of producing stem cells by taking a single cell from an embryo was suggested by the President's Council on Bioethics in a 2005 white paper that examined ways to make the valued cell lines without creating, harming or destroying embryos.
"The president's own bioethics advisory council suggested this approach," said Sean Morrison, director of the University of Michigan Center for Stem Cell Biology, who was not involved in the study. "The administration has a responsibility to now support it."
Michigan is one of at least nine states where it is illegal to derive new human embryonic stem cell lines using traditional methods, even with private funding. Morrison said the new method appears to comply with Michigan law.
The study puts the finishing touches on a highly touted experiment 19 months ago that demonstrated the feasibility of the process but did not actually preserve any embryos, largely for practical reasons.
The approach relies on culling individual embryonic cells using a biopsy technique known as pre-implantation genetic diagnosis, or PGD. About 5,000 couples in the U.S. opt for PGD each year, according to the Society for Assisted Reproductive Technology.
In late 2005, Lanza demonstrated that the technique was possible in mice. The donor embryos were implanted into surrogate mothers and resulted in live births 49% of the time, virtually the same as for intact embryos.
The following year, Lanza's team showed that a single cell taken from an early-stage human embryo could be grown into a stem cell line. To maximize their chances of success, they used all of the cells, called blastomeres, from the donor embryos and therefore couldn't track whether their development would have been hampered by the biopsy.
In the latest study, the researchers used 41 embryos that were frozen by fertility clinics. They thawed them and prompted them to grow to the eight-cell stage, then used a tiny glass pipette to remove one or two blastomeres. Most of the donor embryos continued to develop normally for two more days before they were refrozen.
The individual cells were grown in dishes and surrounded by human embryonic stem cells and other compounds that induced them to develop into embryonic stem cells.
The scientists created four cell lines that were able to grow into all the main tissue types in the body, including neurons and beating heart cells.
Colleagues at UC San Francisco repeated the experiment with two more embryos, but they did not use established stem cells to help the blastomeres grow. They produced a stem cell line that didn't involve any materials derived from dismantled embryos.
There is a potential flaw with the technique: Even the delicate removal of one cell could place an embryo's health at risk.
"How do you demonstrate that the embryo was not harmed?" Landis said. "Right there, you have a significant problem."
Protecting embryo health
The ideal experiment -- in which embryos that have been biopsied to make stem cells are implanted in surrogates so that the babies can be studied for medical problems -- is impossible to conduct for health and ethical reasons.
But Lanza said there is a straightforward solution.
To avoid potential risk to embryos, scientists could piggyback on PGD biopsies that clinics are performing anyway, he said. After the blastomere is removed, it could be nurtured in a dish for about 12 hours until it divides. Then one cell could be used for genetic screening and the other would be available for research.
Landis agreed that stem cells derived in this manner would appear to meet the federal standards.
Lanza said he believed that the method was safe enough to use on spare embryos from fertility clinics and still qualify for federal funding. In his experiments, 80% to 85% of the donor embryos developed to the stage where they could be implanted in a uterus -- a higher rate than at fertility clinics.
"Any clinic would be thrilled with 85%," said Dr. Mark Hughes, director of the Genesis Genetics Institute in Detroit. "Many clinics would be happy with 60%."
Landis said there was no way to know whether the embryos that didn't survive were lost because of the initial thawing or the subsequent biopsy.
Researchers could get some idea by comparing the pregnancy rates of couples that used PGD to those of couples that opted for standard in vitro fertilization.
A study published last year in the New England Journal of Medicine found that among older women who had IVF, those who also used PGD were about 30% less likely to have a baby. But specialists who perform the diagnostic procedure said that the study was flawed and that an alternative reading of the data showed that genetic screening slightly boosted the odds of having a baby.
The entire exercise of trying to satisfy the Bush policy could become moot after the presidential election if a new administration scraps the restrictions. But Lanza said the researchers couldn't wait.
Light Echo Show From Wrenching Gravity Outside Black Hole Predicted
It's well known that black holes can slow time to a crawl and tidally stretch large objects into spaghetti-like strands. But according to new theoretical research from two NASA astrophysicists, the wrenching gravity just outside the outer boundary of a black hole can produce yet another bizarre effect: light echoes.
The light echoes come about because of the severe warping of spacetime predicted by Einstein," says Keigo Fukumura of NASA's Goddard Space Flight Center in Greenbelt, Md. "If the black hole is spinning fast, it can literally drag the surrounding space, and this can produce some wild special effects."
Many black holes are surrounded by disks of searing hot gas that whirl around at nearly the speed of light. Hot spots within these disks sometimes emit random bursts of X-rays, which have been detected by orbiting X-ray observatories. But according to Fukumura and Kazanas, things get more interesting when they take into account Einstein's general theory of relativity, which describes how extremely massive objects like black holes can actually warp and drag the surrounding space-time.
Many of these X-ray photons travel to Earth by taking different paths around the black hole. Because the black hole's extreme gravity warps the surrounding spacetime, it bends the trajectories of the photons so they arrive here with a delay that depends on the relative positions of the X-ray flare, the black hole, and Earth.
But if the black hole rotates very fast, then according to Fukumura and Kazanas' calculations, the delay between the photons is constant, independent of the source's position. They discovered that for rapidly spinning black holes, about 75 percent of the X-ray photons arrive at the observer after completing a fraction of one orbit around the black hole, while the remaining photons travel the exact same fraction plus one or more full orbits.
"For each X-ray burst from a hot spot, the observer will receive two or more flashes separated by a constant interval, so even a signal made up from a totally random collection of bursts from hot spots at different positions will contain an echo of itself," says Kazanas.
Though difficult to discern in the raw data, astronomers can use a Fourier analysis, or other statistical methods, to pick up these hidden echoes. Among other things, a Fourier analysis is a mathematical tool for extracting periodic behavior in a signal that might otherwise seem totally random. The echoes would appear as quasi-periodic oscillations (QPOs). An example of a QPO with a period of 10 seconds might exhibit peaks at 9, 21, 30, 39, 51, and 61 seconds.
If one considers a 10-solar-mass black hole that formed from a dying star, and if the black hole is spinning more than 95 percent of its maximum possible speed, the period of its QPOs would be about 0.7 milliseconds, corresponding to about 1,400 peaks per second, which is three times higher than any QPOs that have been detected around black holes. NASA's Rossi X-ray Timing Explorer satellite could measure such high-frequency QPOs, but the signal would have to be very strong.
Detecting these high-frequency QPOs would do more than just confirm another prediction of Einstein's theory. It would also provide a gold mine of information about the black hole itself. The frequency of the QPOs depends on the black hole's mass, so detecting this echo effect would give astronomers an accurate way to measure the masses of black holes. In addition, notes Kazanas, "This echoes occur only if a black hole is spinning near its maximum possible speed, so it would tell astronomers that the black hole is spinning really fast."
Black Holes Make Light Echo
It's well known by astrophysicists that black holes can slow time to a crawl and tidally stretch large objects into spaghetti-like strands. But according to new theoretical research, the wrenching gravity just outside the outer boundary of a black hole can produce yet another bizarre effect: light echoes.
"The light echoes come about because of the severe warping of spacetime predicted by Einstein," said Keigo Fukumura, an astrophysicist with NASA's Goddard Space Flight Center in Greenbelt, Md. "If the black hole is spinning fast, it can literally drag the surrounding space, and this can produce some wild special effects."
Einsteins black hole emitting light echoes theory validated
A new theoretical research from two NASA astrophysicists has suggested that the wrenching gravity just outside the outer boundary of a black hole can produce an effect known as light echoes, as predicted by Albert Einstein.
Washington, Jan 11 : A new theoretical research from two NASA astrophysicists has suggested that the wrenching gravity just outside the outer boundary of a black hole can produce an effect known as light echoes, as predicted by Albert Einstein.
Keigo Fukumura and his colleague Demosthenes Kazanas from the Goddard Space Flight Center carried out the research.
"The light echoes come about because of the severe warping of spacetime predicted by Einstein," said Keigo Fukumura of NASA's Goddard Space Flight Center in Greenbelt, Md. "If the black hole is spinning fast, it can literally drag the surrounding space, and this can produce some wild special effects," he added.
Many black holes are surrounded by disks of searing hot gas that whirl around at nearly the speed of light. Hot spots within these disks sometimes emit random bursts of X-rays, which have been detected by orbiting X-ray observatories.
But according to Fukumura and Kazanas, things get more interesting when they take into account Einstein's general theory of relativity, which describes how extremely massive objects like black holes can actually warp and drag the surrounding space-time.
"For each X-ray burst from a hot spot, the observer will receive two or more flashes separated by a constant interval, so even a signal made up from a totally random collection of bursts from hot spots at different positions will contain an echo of itself," said Kazanas.
Though difficult to discern in the raw data, astronomers can use a Fourier analysis, or other statistical methods, to pick up these hidden echoes, which would appear as quasi-periodic oscillations (QPOs).
The detection of these QPOs would also provide much information about the black hole itself.
Because the frequency of the QPOs depends on the black hole's mass, detecting this echo effect would give astronomers an accurate way to measure the masses of black holes.
"This echoes occur only if a black hole is spinning near its maximum possible speed, so it would tell astronomers that the black hole is spinning really fast," said Kazanas.
A hacking virus has warned for the windows user,, it may attact on your log in information.
Security experts are warning about a stealthy Windows virus that steals login details for online bank accounts.
In the last month, the malicious program has racked up about 5,000 victims - most of whom are in Europe.
Many are falling victim via booby-trapped websites that use vulnerabilities in Microsoft's browser to install the attack code.
Experts say the virus is dangerous because it buries itself deep inside Windows to avoid detection.
The malicious program is a type of virus known as a rootkit and it tries to overwrite part of a computer's hard drive called the Master Boot Record (MBR).
This is where a computer looks when it is switched on for information about the operating system it will be running.
"If you can control the MBR, you can control the operating system and therefore the computer it resides on," wrote Elia Florio on security company Symantec's blog.
Mr Florio pointed out that many viruses dating from the days before Windows used the Master Boot Record to get a grip on a computer.
Once installed the virus, dubbed Mebroot by Symantec, usually downloads other malicious programs, such as keyloggers, to do the work of stealing confidential information.
Most of these associated programs lie in wait on a machine until its owner logs in to the online banking systems of one of more than 900 financial institutions.
The Russian virus-writing group behind Mebroot is thought to have created the torpig family of viruses that are known to have been installed on more than 200,000 systems. This group specialises in stealing bank login information.
Security firm iDefense said Mebroot was discovered in October but started to be used in a series of attacks in early December.
Between 12 December and 7 January, iDefense detected more than 5,000 machines that had been infected with the program.
Analysis of Mebroot has shown that it uses its hidden position on the MBR as a beachhead so it can re-install these associated programs if they are deleted by anti-virus software.
Although the password-stealing programs that Mebroot installs can be found by security software, few commercial anti-virus packages currently detect its presence. Mebroot cannot be removed while a computer is running.
Independent security firm GMER has produced a utility that will scan and remove the stealthy program.
Computers running Windows XP, Windows Vista, Windows Server 2003 and Windows 2000 that are not fully patched are all vulnerable to the virus.
Stem cell the cell for colon is a mordern and latest invention that can change the generation next.
Scientists at an Alameda company claim they have created human embryonic stem-cell colonies without destroying an embryo -- a breakthrough they say has the potential to end the ethical debate surrounding the use of embryos to derive the cells.
The development was announced Thursday and is an improvement on a technique that the White House and other skeptics scoffed at when it was first revealed in 2006.
"This new approach addresses the president's ethical concerns," said William Caldwell, chief executive of Advanced Cell Technology, which has offices on Harbor Bay Parkway and in Worcester, Mass.
But Story Landis, who heads the federal government's National Institutes of Health stem-cell task force, was non-committal.
While calling the new procedure "extremely interesting," she added, "we need to know more" about the method to make sure that embryos are not harmed in the process.
Richard Doerflinger, a bioethicist at the U.S. Conference of Catholic Bishops, was highly critical.
"It seems they've made some progress in reducing the direct destructiveness of the procedure," he said. However, he added, "this is a rather shaky claim about making this procedure safe," because while most of the embryos used to create the stem-colonies survived, a few did not.
Moreover, he said, creating stem-cell colonies from skin -- as some scientists have shown to be possible recently -- is far preferable because "it totally does not have any problem in terms of harming
or destroying embryos."
The new study was published Thursday in the journal Cell Stem Cells.
While the study involves a technique developed by Advanced Cell Technology, it was replicated by researchers at StemLifeLine in San Carlos.
"If the White House approves this new methodology, researchers could effectively double or triple the number of stem cell lines available within a few months," said the Alameda's company's Dr. Robert Lanza, the paper's senior author. "Too many needless deaths continue to occur while this research is being held up."
When Advanced Cell Technology first published a study detailing the technique in 2006, it said it removed a single cell from a tiny, early-stage embryo and demonstrated that the cell could be turned into a stem-cell colony without destroying the embryo.
That was hailed at the time by some stem-cell advocates as a major breakthrough.
Because human embryonic stem cells can develop into any type of tissue, many scientists believe it may be possible one day to create colonies of them that can be used for everything from growing replacement organs to creating treatments for diabetes and other diseases.
However, soon after Advanced Cell Technology's first study was published, the company acknowledged it actually had not kept alive some of the embryos used to create the colonies. Its executives explained that their purpose was merely to demonstrate the technique would work, not to keep the embryos alive.
Nonetheless, the revelation in 2006 was denounced by Doerflinger. White House officials also said the procedure continued to raise ethical concerns about deriving stem-cell colonies from embryos.
In this latest study, the company's executives said they found a better way to grow the cells removed from the embryos and that 80 percent of the embryos developed normally, although all of them eventually were frozen.
Susan Fisher, a stem-cell researcher at the University of California-San Francisco, praised the technique.
"For people for whom embryonic destruction is an obstacle in this kind of work, this is certainly an advance," said Fisher, who also provided advice for the study.
Staff writer Peter Hegarty contributed to this report.
More about Stem cell
Stem cells are cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types. Research in the stem cell field grew out of findings by Canadian scientists Ernest A. McCulloch and James E. Till in the 1960s. The two broad types of mammalian stem cells are: embryonic stem cells that are found in blastocysts, and adult stem cells that are found in adult tissues. In a developing embryo, stem cells can differentiate into all of the specialized embryonic tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing specialized cells, but also maintain the normal turnover of regenerative organs, such as blood, skin or intestinal tissues.
As stem cells can be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture, their use in medical therapies has been proposed. In particular, embryonic cell lines, autologous embryonic stem cells generated through therapeutic cloning, and highly plastic adult stem cells from the umbilical cord blood or bone marrow are touted as promising candidates.