By Nikhil Swaminathan After seven years of toiling, scientists at the Wake Forest University School of Medicine and Harvard School of Medicine report they have isolated stem cells from a new source: amniotic fluid. The researchers not only succeeded in separating the progenitor cells from the many cells residing in the watery fluid in the placenta surrounding an embryo, but were also able to coax the cells to differentiate into muscle, bone, fat, blood vessel, liver and nerve cells. According to lead author Anthony Atala, director of Wake Forest's Institute of Regenerative Medicine, 99 percent of the U.S., population could conceivably find genetic matches for tissue regeneration or engineered organs from just 100,000 amniotic fluid samples. In its research, the team isolated stem cells via amniocentesis--a common procedure performed about 16 weeks into pregnancy during which amniotic fluid is drawn to test for genetic disorders in a fetus--as well as from the placenta after birth. The researchers write in their paper--published in this week's Nature Biotechnology--that stem cells make up 1 percent of all the cells in amniotic fluid samples. "It's been known for decades that there are cells in amniotic fluid," Atala says. "The embryo is constantly shedding all these cells, as it's developing, to the amniotic fluid. The baby's actually breathing in, swallowing the fluid, and it's all coming out through all the pores and gets trapped in the placenta." © 1996-2007 Scientific American, Inc.

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Link ID: 9818 - Posted: 06.24.2010

By Rick Weiss Scientists in Germany said yesterday that they had retrieved easily obtained cells from the testes of male mice and transformed them into what appear to be embryonic stem cells, the versatile and medically promising biological building blocks that can morph into all kinds of living tissues. If similar starter cells exist in the testes of men, as several scientists yesterday said they now believe is likely, then it may not be difficult for scientists to cultivate them in laboratory dishes, grow them into new tissues and transplant those tissues into the ailing organs of men who donated the cells. The technique would have vast advantages over the current approach to growing "personalized" replacement parts -- an approach that has stirred intense political controversy because it requires the creation and destruction of cloned human embryos as stem cell sources. The new work suggests that every male may already have everything he needs to regenerate new tissues -- at least with a little help from his local cell biologist. No one knows whether cells with similar potential exist inside female bodies -- a crucial question if women, too, are to have access to new tissues genetically matched to themselves and so not susceptible to rejection by their immune systems. But recent studies have led many researchers to conclude that the possibility is greater than previously believed. © 2006 The Washington Post Company

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Link ID: 8715 - Posted: 06.24.2010

Even for scientists, it's not every day you see a hairless mouse glowing bright green under a fluorescent light. And for scientists searching for stem cells that could grow into nerve or brain cells, seeing such a mouse meant finding a possible whole new source of such cells. The scientists had given the mouse a gene so that areas would glow green where such stem cells might be found. They expected part of the mouse around the head to glow green. Instead, the entire mouse was aglow. "I'll never forget the minute that we made that observation," says Robert Hoffman, president of AntiCancer, Inc., where the finding took place. Because of that moment, which Hoffman says was, in fact, a "lucky discovery," company scientists have been working on what could be a new source of adult stem cells. Their most recent research, published in Proceedings of the National Academy of Sciences (PNAS), shows that they've been able to use stem cells taken from a mouse hair follicle to help regenerate damaged nerves in mice. In previous research, also published in PNAS, they showed the stem cells could become special brain cells called neurons. © ScienCentral, 2000-2006.

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Link ID: 8658 - Posted: 06.24.2010

Carl T. Hall, Chronicle Science Writer Researchers in San Diego have designed mice containing fully functional human nerve cells as a novel way to study and potentially treat neurodegenerative diseases such as Parkinson's and Alzheimer's. The neurons were formed in the brains of mice that had been injected with human embryonic stem cells as 2-week-old embryos. Studies at the Salk Institute for Biological Sciences in La Jolla showed that the human cells migrated throughout the mouse brain and took on the traits of their mouse-cell neighbors. The results present direct evidence that primitive human stem cells can be cultured in the lab, be injected into an animal, and then develop into a particular type of desired cell. The report appears in this week's Proceedings of the National Academy of Sciences. Scientists said it was the first time cultured human embryonic stem cells have been shown to develop into a particular type of cell in the body of another living species. Creation of a so-called "mouse-human chimeric nervous system" stops well short of spawning a mouse with a human-like cerebral cortex. In fact, all the brain structures of the four mice used in the Salk experiments had been formed before the human cells were injected, and less than 0.1 percent of the mice brain cells were found to be of human origin. ©2005 San Francisco Chronicle

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Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 5: The Sensorimotor System
Link ID: 8309 - Posted: 06.24.2010

By Charles Q. Choi Mothers could literally always have their kids on their minds. Researchers find that in mice, cells from fetuses can migrate into a mother's brain and apparently develop into nervous system cells. The discovery comes from Gavin S. Dawe of the National University of Singapore and Zhi-Cheng Xiao of Singapore General Hospital, along with their colleagues from China and Japan. They were looking to design therapies for stroke or diseases such as Alzheimer's. Scientists have known for years that fetal cells can enter a mother's blood; in humans, they may remain there at least 27 years after birth. Like stem cells, they can become many other kinds of cells and in theory might help repair damaged organs. The neurobiologists bred normal female mice with males genetically modified to uniformly express a green fluorescent protein. They found green fetal cells in the mothers' brains. "In some regions of some mothers' brains, there are as many as one in 1,000 to sometimes even 10 in 1,000 cells of fetal origin," Xiao reports. The fetal cells transformed into what seem like neurons, astrocytes (which help to feed neurons), oligodendrocytes (which insulate neurons) and macrophages (which ingest germs and damaged cells). Moreover, after the scientists chemically injured the mouse brains, nearly six times as many fetal cells made their way to damaged areas than elsewhere, suggesting the cells could be responding to molecular distress signals released by the brain. © 1996-2005 Scientific American, Inc.

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Link ID: 8163 - Posted: 06.24.2010

Christen Brownlee Two independent groups of scientists have devised ways to isolate embryonic stem cells from mice without destroying viable embryos. These new methods are intended to satisfy the ethical concerns of people who oppose destroying human embryos to do research or treat disease. Unlike any cell known in adults, embryonic stem cells can morph into virtually any of the body's cell types, such as nerve, muscle, or heart. Many researchers have proposed exploiting this unique capability to make new cells for the treatment of injuries or diseases such as Parkinson's disease (SN: 4/2/05, p. 218: http://www.sciencenews.org/articles/20050402/bob10.asp). However, to isolate a new line of embryonic stem cells, scientists have had to first destroy an early embryo. "Many people, including the President, are concerned about destroying life in order to save life," says Robert Lanza of Advanced Cell Technology in Worcester, Mass. Seeking to resolve this dilemma, Lanza and his colleagues looked to a technique commonly used to diagnose genetic diseases in embryos. Known as pre-implantation genetic diagnosis, the procedure removes one cell from an eight-cell-stage embryo and examines its DNA for defects. The remaining seven-cell embryo, after being implanted in the mother's womb, can develop into a normal baby. ©2005 Science Service.

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Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 5: The Sensorimotor System
Link ID: 8053 - Posted: 06.24.2010

Christen Brownlee By fusing an embryonic stem cell with an adult skin cell, researchers have created cells that retain valuable embryonic characteristics but carry the adult cell's genes. This new method might eventually lead to stem cell lines that match a patient's DNA while avoiding the destruction of human embryos, a process that some people find morally unacceptable. Scientists envision someday using embryolike cells to grow tissues for transplant or transplanting such cells into a patient, where they would grow to replace damaged or diseased tissues. If these cells carried a patient's genetic material, they might sidestep the risk of a destructive immune reaction. Some scientists also predict that cells with embryonic properties could give researchers a new way to study genetic diseases. Cells that carry the DNA from a patient with a genetic disease could differentiate in a petri dish, permitting scientists to observe how disease characteristics develop. Korean scientists recently created the first lines of embryonic stem cells derived from clones made with people's cells. However, the team used more than 100 human eggs, which are difficult to obtain, and created early human embryos, which they destroyed to harvest stem cells (SN: 5/21/05, p. 323: http://www.sciencenews.org/articles/20050521/fob1.asp). Copyright ©2005 Science Service.

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Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 7806 - Posted: 06.24.2010

By Clive Cookson The late 1990s was the most productive period in the history of biological research. The birth of Dolly, the first cloned mammal, was quickly followed by the first successful derivation of human embryonic stem cells and then, as the new millennium dawned, the completion of the Human Genome Project. Since then the media have amplified these achievements, with the enthusiastic encouragement of many of the researchers involved, to create intense public excitement about a new era of regenerative medicine. Some people imagine that within a few years it will be possible, through some still obscure combination of stem cells, cloning and genetic engineering, to create new cells and eventually whole organs to replace those that fail through disease, accident or old age. That promise is counterbalanced by ethical and religious objections to stem cell research--particularly to the idea that embryos could be created especially for research and then destroyed--and fears that therapeutic cloning could open the door to reproductive cloning. For many people the very phrase "stem cells" sums up all the excitement and fears. But there is widespread ignorance about stem cells and wishful thinking about how quickly their potential will be achieved. This report is intended to shed scientific light on the future of stem cell research--and the associated policy issues that are driving national and state governments to commit billions of dollars of public funds to the field. © 1996-2005 Scientific American, Inc

Related chapters from BP6e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 5: The Sensorimotor System
Link ID: 7553 - Posted: 06.24.2010

Christen Brownlee Made-to-order stem cells that genetically match a patient's own tissues could provide a perfect patch for replacing cells damaged by injury or disease. This approach would avoid immune rejection (SN: 4/2/05, p. 218: http://www.sciencenews.org/articles/20050402/bob10.asp). By priming embryonic cells with genetic material derived from people with problems that stem cells may one day treat, researchers have isolated 11 new lines of stem cells that exactly match the patients' own DNA. Therapeutic cloning, which yields stem cells that can be used to treat patients, differs from reproductive cloning, which creates a new organism. However, the two types of cloning use many of the same techniques. Scientists start by removing an egg's nucleus, which carries most of a cell's genetic material. They then inject the egg with a nucleus from a donor cell, such as a skin cell. After the cell divides and grows into a multicelled embryo, researchers doing therapeutic cloning extract stem cells that carry the same genetic signature as that of the donated nucleus. Until recently, researchers' ambitions were hampered by difficulties in creating clones of human cells. Last year, a team led by Woo Suk Hwang at Seoul National University in South Korea succeeded in making the first human clone and in isolating stem cells from it (SN: 2/14/04, p. 99: http://www.sciencenews.org/articles/20040214/fob1.asp). Copyright ©2005 Science Service.

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Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 7383 - Posted: 06.24.2010

Much of the controversy surrounding research on stem cells hinges on the source of the cells--particularly whether they come from embryonic sources or adult ones. Now research published online by the Proceedings of the National Academy of Sciences provides new insight into the abilities of stem cells taken from hair follicles. The results indicate that these adult stem cells can develop into neurons. Inside a hair follicle is a small bulge that houses stem cells. As hair follicles cycle through growth and rest periods, these stem cells periodically differentiate into new follicle cells. Yasuyuki Amoh of AntiCancer, Inc. and his colleagues isolated stem cells from the whiskers of mice and tested their ability to become more sophisticated cell types. The researchers cultured the cells and after one week discovered that they had changed into neurons and two other cell types, known as astrocytes and oligodendrocytes, that are associated with neurons. According to the report, when left for longer periods lasting weeks or months, the stem cells could differentiate into a variety of cell types, including skin and muscle cells. © 1996-2005 Scientific American, Inc.

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Link ID: 7096 - Posted: 06.24.2010

Jonathan Knight George W. Bush has won the presidential election. But Republicans are not the only ones celebrating the poll results: biologists who wish to pursue human embryonic stem-cell research have also had good news. All they have to do is move to California, if they aren't already there, and apply for a share of the $3 billion that voters have just approved for their field. By 59% to 41% of votes, Californians said "yes" to Proposition 71, the California Stem Cell Research and Cures Initiative, which will raise around $300 million a year for a decade through bond sales. The money will pay for research that has not been eligible for government money since 9 August 2001, when President George W. Bush limited federal spending on human embryonic stem-cell research to cell lines in existence as of that date. The creation of new cell lines involves the destruction of a days-old human embryo. Most biomedical researchers believe that the number of lines available under the 2001 rule will be inadequate to realize the potential of stem-cell research, which might give insight into the causes of degenerative diseases such as muscular dystrophy and Parkinson's. Such discoveries may to lead to new treatments, and therapies that use embryonic stem cells themselves to replace damaged tissues could also emerge. ©2004 Nature Publishing Group

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Link ID: 6368 - Posted: 06.24.2010

When embryonic stem cells prove their medical merits, public support--both social and financial--will probably grow substantially, said National Institutes of Health director Elias A. Zerhouni in a panel discussion held Wednesday in Washington, D.C. by Scientific American. Comparing the state of embryonic stem cell science today to that of organ transplantation during the 1950s and '60s, Zerhouni noted that public consensus in favor of organ transplants only emerged when the "greater good" offered by the treatment had been fully demonstrated. "This is the people's dollars we're talking about," Zerhouni stated, "and that's where the rubber hits the road." Without public consensus, he explained, consensus in Congress to expand funding for embryonic stem cell science is unlikely. "California is going to test that," he added. A November 2nd California ballot initiative seeking to raise $3 billion for stem cell research in that state loomed large in the panel's discussion of the best way for science and society to proceed with regard to embryonic stem cell research. If passed, California's Proposition 71 might break an essential impasse in the debate over using embryos in research. Proponents say that without adequate funding and materials, U.S. scientists cannot fully explore the potential of embryonic cells. Critics counter that without demonstrated medical potential, the ethical risks of expanding embryo research are too great. © 1996-2004 Scientific American, Inc.

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Link ID: 6177 - Posted: 06.24.2010

By Robert Lanza and Nadia Rosenthal Stem cells raise the prospect of regenerating failing body parts and curing diseases that have so far defied drug-based treatment. Patients are buoyed by reports of the cells' near-miraculous properties, but many of the most publicized scientific studies have subsequently been refuted, and other data have been distorted in debates over the propriety of deriving some of these cells from human embryos. Provocative and conflicting claims have left the public (and most scientists) confused as to whether stem cell treatments are even medically feasible. If legal and funding restrictions in the U.S. and other countries were lifted immediately, could doctors start treating patients with stem cells the next day? Probably not. Many technical obstacles must be overcome and unanswered questions resolved before stem cells can safely fulfill their promise. For instance, just identifying a true stem cell can be tricky. For scientists to be able to share results and gauge the success of techniques for controlling stem cell behavior, we must first know that the cells we are studying actually possess the ability to serve as the source, or "stem," of a variety of cell types while themselves remaining in a generic state of potential. But for all the intensive scrutiny of stem cells, they cannot be distinguished by appearance. They are defined by their behavior. © 1996-2004 Scientific American, Inc.

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Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 5: The Sensorimotor System
Link ID: 5549 - Posted: 06.24.2010

BY JAMIE TALAN Scientists have transplanted adult stem cells from the bone marrow of rats into the brains of rat embryos and found that thousands of the cells survive into adulthood, raising the possibility that someday developmental abnormalities could be prevented or treated in the womb. Dr. Ira Black, chairman of the department of neuroscience at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, said the cells took on the properties of brain cells, migrating to specific regions and taking up characteristics of neighboring cells. "They exhibited the same flexibility in the living brain as we had observed in culture," said Black, director of the school's Stem Cell Center. His findings were published today in the Journal of Neuroscience. Copyright © Newsday, Inc. Produced by Newsday Electronic Publishing.

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Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 5: The Sensorimotor System
Link ID: 5455 - Posted: 06.24.2010

One of the many mysteries of stem cells is how they morph from a universal cell type, full of possibility, into one that's tailored for a specific job. Now scientists say they've hit on a startling explanation for some of these cells: A minuscule RNA molecule helps guide the early development of neurons and other brain cells. The finding is the latest addition to an ever-lengthening repertoire for small RNA molecules. Small RNA molecules can bind to and blunt expression of DNA stretches with a complementary sequence. The first clues that they have a hand in stem cell development came in plants. Then scientists reported that members of a class of RNA molecules called microRNAs direct the development of blood and bone marrow cells in mice. These studies and others suggested that small RNAs play a leading role in development. The possibility that they might be important in nerve cell development intrigued neuroscientists Fred Gage and Tomoko Kuwabara of the Salk Institute in La Jolla, California, and colleagues, who were studying how adult neural stem cells differentiate. The group probed human, adult neural stem cells for small RNA molecules and fished out more than 50 types. One double-stranded molecule stood out: It matched a DNA site that a protein key to neural development binds to. That protein, called NRSF, blocks the expression of 64 different genes and prevents them from turning a cell into a neuron. Furthermore, the team found, differentiating neural stem cells expressed the RNA at high levels, and introducing extra doses spurred neural stem cells to become neurons. Copyright © 2004 by the American Association for the Advancement of Science.

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Link ID: 5159 - Posted: 06.24.2010

Both of the leading Democratic candidates say the federal government should support embryonic stem cell research that could lead to cures for millions of patients. As this ScienCentral News video reports, a leading stem cell researcher left the U.S. to pursue that dream. South Korean scientists announced on February 12th that they had cloned human stem cells, which could be used to replace cells damaged by disease or aging. The research was announced in the U.S. but is strictly limited here, which has forced some Americans to do their research abroad. Roger Pedersen, professor of regenerative medicine at the University of Cambridge and director of the Cambridge Centre for Stem Cell Biology and Medicine, decided in 2001 to leave the University of California at San Francisco for England when President Bush banned research that creates any type of human embryo. "The United States government had at that moment cancelled its plans, suspended really any consideration of funding this area of research," Pedersen says. "And I had by then dedicated my entire lab to carrying out research on human embryonic stem cells. I had to consider other options," he says. "One way would be to stop working on human embryonic stem cells, but I didn't choose that option. I chose to move to a country that was willing to provide support, broad support for this research." © ScienCentral, 2000-2004.

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Link ID: 5064 - Posted: 06.24.2010

David Ewing Duncan Doug Melton sighs. For hours, this Harvard molecular embryologist has been toiling in a small personal lab attached to his office in Cambridge, Mass., where he's trying to save the lives of his two children. Twelve-year-old Sam and 16-year-old Emma have been diagnosed with insulin- dependent diabetes. If Melton's research is successful, they could be spared the organ failure, blindness and heart disease that eventually afflict diabetics -- but only if Melton is allowed to continue his work by lawmakers in Washington, D.C. They worry that his methods might be immoral or dangerous and are threatening to shut down his work. Melton, the Thomas Dudley Cabot Professor in the Natural Sciences at Harvard University, studies the mechanisms of how embryonic stem cells form in mice and humans just after an egg is fertilized. These stem cells have the unique ability to grow into any tissue in the body -- whether of a liver, eyeball or skeleton. ©2004 San Francisco Chronicle

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Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 5047 - Posted: 06.24.2010

Scientists hope they'll serve as brain repair kit Carl T. Hall, Chronicle Science Writer A mysterious type of stem cell found in the brain appears to be a possible wellspring of fresh nerve cells and, when something goes haywire, the starting point of a common form of tumor, scientists are reporting. The finding lays new ground for understanding the fundamental biology of stem cells in the adult brain. Scientists hope these cells and the signaling molecules that govern their fate might someday serve as a repair kit for treating brain injury, strokes or neurodegenerative diseases such as Parkinson's. The study resulted from a collaboration of neuroscientists and brain surgeons at UCSF Medical Center, led by Dr. Nader Sanai, a 26-year-old neurosurgery resident. Dr. Mitchel Berger, chair of neurosurgery, and stem- cell expert Arturo Alvarez-Buylla were senior authors. ©2004 San Francisco Chronicle

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Link ID: 5009 - Posted: 06.24.2010

Chemical might help human cells reach clinic. ERIKA CHECK A humble marine snail has helped scientists to unravel the signals that keep stem cells young. Human embryonic stem (ES) cells can give rise to almost all of the body's different cell types. They could eventually provide patients with replacement tissues - but there are some roadblocks that currently prevent researchers from putting the cells into patients' bodies. One problem is that scientists don't yet know how to control the cells' transformations into other types. Another is that the cells cannot be grown without help from mouse cells, which means that they could be contaminated with mouse proteins. © Nature News Service / Macmillan Magazines Ltd 2003

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Link ID: 4730 - Posted: 06.24.2010

A vote to permit stem-cell research is a vote to alleviate suffering, says former MP REGINALD STACKHOUSE By REGINALD STACKHOUSE Let's call him Jack. Let's also admit he's serving a life sentence. Jack will spend the rest of his life behind locked doors. But not for murder. Not for child abuse. Nor any other crime. Alzheimer's disease has taken over Jack's brain and he can't be trusted to live outside a security-controlled care centre. It's a pathetic fate for an academic whose life had been dedicated to the mind. Pathetic to be cut off from family and friends. Pathetic never to know his first grandchild. Pathetic most of all because this could be prevented. © 2003 Bell Globemedia Interactive Inc.

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Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 5: The Sensorimotor System
Link ID: 4239 - Posted: 06.24.2010