Gene screen hints at what makes stem cells special. KENDALL POWELL Two teams have found the genes that distinguish stem cells from ordinary cells1,2. The list might help scientists find new types of stem cell, and coax them to grow into replacement tissues and organs. It might also resolve arguments about the merits of different types of stem cell. "People who want to battle out which stem cell can do what, can do so by manipulating some of these genes," says developmental biologist Miguel Ramalho-Santos of Harvard University in Cambridge, Massachusetts. About 200 genes are at least two to three times more active in mouse stem cells than in mature brain or blood cells, the studies found. The researchers looked at embryonic stem cells, which can give rise to all types of cell, and adult nerve and blood stem cells, which are dedicated to repairing specific tissues. © Nature News Service / Macmillan Magazines Ltd 2002

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 15: Language and Lateralization
Link ID: 2637 - Posted: 06.24.2010

Bone marrow could save eyesight. KENDALL POWELL Bone marrow stem cells might one day deliver drugs to the eye, halting age- and diabetes-related blindness. The cells can treat a genetic condition that causes mouse retinas to degenerate1. When the stem cells - that usually make blood vessels - were injected into the fluid-filled space of the eye they became part of developing blood vessels in the retina. Faulty capillary formation is central to both the leading causes of adult blindness in the US: diabetic retinopathy and age-related macular degeneration. © Nature News Service / Macmillan Magazines Ltd 2002

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 7: Vision: From Eye to Brain
Link ID: 2392 - Posted: 06.24.2010

Copyright © 2002 Scripps Howard News Service By LEE BOWMAN, Scripps Howard News Service BOSTON - Scientists may be moving closer to the day when neurologists can say "brain, heal thyself." Until recently, experts were sure that new brain cells were impossible for adults to come by, that all the gray matter we get is pretty much in place well before we reach adolescence. But there's new evidence that a few regions of the brain keep churning out new cells, and new hope that the precursors of those specialized cells can be coaxed into producing other types of brain cells needed to reverse or repair damaged regions. Copyright © 2001 Nando Media

Related chapters from BN: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 15: Language and Lateralization
Link ID: 1550 - Posted: 06.24.2010

Science trumps politics Just as the Senate gears up to debate the contentious issue of human cloning, a number of startling advances are emerging that may offer alternatives to the technique. In fact, the very scientists who forced the issue by creating the first cloned human embryo last October are announcing advances toward obtaining genetically matched replacement cells for patients without creating a viable embryo. And other scientists are making progress using adult stem cells to generate new tissues. Until now, the only known way to provide new body cells containing a patient's own DNA has been to create an early-stage cloned embryo to produce the versatile stem cells that can then be prodded to become any type of body tissue. But because embryo research is such an explosive issue, progress has been stymied and lawmakers have threatened to ban the work. © 2002 U.S.News & World Report Inc. All rights reserved.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 1491 - Posted: 06.24.2010

Sylvia Pagán Westphal, Boston A stem cell has been found in adults that can turn into every single tissue in the body. It might turn out to be the most important cell ever discovered. Until now, only stem cells from early embryos were thought to have such properties. If the finding is confirmed, it will mean cells from your own body could one day be turned into all sorts of perfectly matched replacement tissues and even organs. If so, there would be no need to resort to therapeutic cloning - cloning people to get matching stem cells from the resulting embryos. Nor would you have to genetically engineer embryonic stem cells (ESCs) to create a "one cell fits all" line that does not trigger immune rejection. The discovery of such versatile adult stem cells will also fan the debate about whether embryonic stem cell research is justified. © Copyright Reed Business Information Ltd.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 1400 - Posted: 06.24.2010

Researchers isolate neuronal progenitor cells from ESCs By Laura DeFrancesco Two reports in the December issue of Nature Biotechnology show that the potential of human embryonic stem cells is being realized.1,2 One group led by S.C. Zheung at the University of Wisconsin, Madison, and another led by B.E. Reubinoff from Hadassah University, Jerusalem, have isolated highly purified populations of neuronal progenitor cells from human embryonic stem cell (ESC) cultures. These papers demonstrate that human ESC cultures can be enriched for a single and specific progenitor cell type. Furthermore, the cells, which by all measures appear to be neuronal progenitor cells, behave this way in vitro and in vivo, and give rise to the major cell types of the central nervous system (CNS). The Scientist 16[1]:28, Jan. 7, 2002 © Copyright 2002, The Scientist, Inc. All rights reserved.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 1276 - Posted: 06.24.2010

By NICHOLAS WADE If stem cells ever show promise in treating diseases of the human brain, any potential therapy would need to be tested in animals. But putting human brain stem cells into monkeys or apes could raise awkward ethical dilemmas, like the possibility of generating a humanlike mind in a chimpanzee's body. No such experiments are planned right now. But in a paper today in the journal Science, a group of scientists and ethicists is advising researchers to exercise care with such experiments, particularly if they should lead to a large fraction of a chimpanzee's brain's being composed of human neurons. The group, led by Ruth R. Faden, a biomedical ethicist at Johns Hopkins University, acknowledged the view that monkeys and apes should not be experimented on at all, but nevertheless considered what kinds of research should be permitted if the experiments were required by regulatory authorities. Clinical trials often depend on previous tests with rats or mice that have some equivalent of the human disease. But for some diseases that affect the human brain, the rodent models may not serve so well. If stem cell therapies for Alzheimer's or Parkinson's disease were to be developed, the Food and Drug Administration might require tests in monkeys or apes before permitting clinical trials. Copyright 2005 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 7648 - Posted: 07.15.2005

Scientists say they have duplicated the process of generating new adult brain cells in a controlled way in the lab. It is hoped the technique, tested so far on animal cells, will eventually allow scientists to produce a limitless supply of a person's own brain cells. The researchers believe they could potentially be used to treat disorders like Parkinson's disease and epilepsy. The study, by the McKnight Brain Institute, is published in Proceedings of the National Academy of Sciences. It is not the first time that immature stem cells have been manipulated in the laboratory to become brain cells. But the researchers say nobody else has replicated the process of cell maturation that goes on in the brain in such complete and close step-by-step detail before. However, a leading British expert has stressed the importance of not hyping the potential of work in this field. The researchers harnessed a technique which had already been used to produce adult blood cells outside the body. They collected immature neural stem cells at a primitive stage of development from mice and used chemicals to induce them to mature. During the process they snapped images of the cells every five minutes using a special microscope. This enabled them to create a short film showing the cells developing stage by stage into fully fledged adult brain cells (neurons). They were also able to track the physiological changes that take place during development in closer detail than ever before. (C)BBC

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 7495 - Posted: 06.14.2005

US scientists believe they could use brain stem cells to cure diabetes. Although the work is not yet ready to be tested on human patients, results in animals have been promising, say the Stanford University researchers. They were able to coax the immature brain cells to develop into the insulin-producing islet cells that are lacking in diabetes. Eventually, these could be used for curative transplants, the scientists told the journal PLoS Medicine. Scientists have already been looking at using stem cells taken from embryos to treat diabetes. These are primitive "master" cells that can be programmed to become many kinds of tissue. However, there have been concerns that these cells can turn cancerous, are difficult to work with in the laboratory and raise ethical dilemmas. Dr Seung Kim and colleagues looked at whether adult stem cells taken from the brain might work just as well and avoid some of these issues. Dr Kim said: "When you look at islet cells you realise that they resemble neurons." In some insects, such as fruit flies, the cells that produce insulin and regulate blood sugar are also neurons. (C)BBC

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 7254 - Posted: 04.26.2005

12-year-old Nathan Van Vleck of Pittsford died after a nearly lifelong fight with an exceedingly rare inherited disease known as vanishing white matter (VWM) disease. As Nathan's illness progressed, the family discussed how it might help other families and patients coping with VWM, and the family decided to allow the study of some of Nathan's brain cells for research purposes. Immediately upon his death in the hospital, a team of neuropathologists and neurobiologists worked through the night to isolate some of Nathan's brain cells, which were then grown and studied in the laboratory. The outcome was an unprecedented in-depth look at the brain cells of a VWM patient. The investigation not only yielded important knowledge about how the disease affects the brain, but it also marks one of the first times that scientists have been able to isolate neural stem cells from a patient and use them to learn what is going wrong in the brain of a patient with a complex neurological disease. The team of scientists from the University of Rochester Medical Center reported its results in the March issue of the prestigious research journal Nature Medicine. VWM targets cells that make up part of the brain's white matter, turning the normally strong and durable substance into a yellowish, gelatin-like material. While we hear a great deal about the importance of our "gray matter," a term that refers to crucial brain cells known as neurons, the brain's white matter is also vital to our health. Our white matter is mostly made up of glial cells that insulate the connections between neurons. In VWM, as the white matter gradually disappears, a child typically has trouble talking and walking. As the disease progresses over several years the child has seizures, goes into a coma and often dies before reaching teen-age years. Currently there is no treatment.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 7251 - Posted: 04.26.2005

Scientists have transformed stem cells from adult human bone marrow into nerve cells by transplanting them into damaged chicken embryos. The University of Oslo team hopes the breakthrough could lead to a new source of cells to treat brain diseases such as Parkinson's. It appeared that the embryos' internal repair mechanism acted on the cells to profoundly change their make-up. Details are published in Proceedings of the National Academy of Sciences. Stem cells are master cells with the ability to form different kinds of tissue. But those from adult bone marrow normally produce blood and immune system cells. However, experiments have suggested it might be possible to coax them into becoming nerves. Attempts to achieve this have, in the past, been relatively unsuccessful. In a small number of cases, scientists have managed to identify the molecular hallmarks of neurons - but they have not been able to create properly formed interconnected cells. However, bone marrow stem cells implanted into chicken eggs developed fully functional physical features. They were also converted at a high rate of about 10%. Writing in PNAS, the researchers said: "This may open new possibilities for a high-yield production of neurons from a patient's own bone marrow." The Norwegian team used a micro-surgery technique to cut out a small section of the developing spinal cord within the chicken egg. Human haematopoietic stem cells (hHSCs) from bone marrow were then implanted into the damaged area. The eggs were incubated before the embryos were removed, and spinal cord slices containing human cells dissected out and analysed. Damage to the developing brain and spinal cord of the chicken embryo is automatically repaired through a process called regulative regeneration. (C)BBC

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 5: The Sensorimotor System
Link ID: 7073 - Posted: 03.23.2005

University of Toronto researchers have shown that human retinal stem cells transplanted into the eyes of mice and chicks can successfully regenerate. The research, published in the Oct. 19 issue of The Proceedings of the National Academy of Sciences, documents the development of transplanted human retinal stem cells into light-sensing photoreceptor cells and retinal pigment epithelial (RPE) cells, the cells which bounce light and images back onto the retina. "We transplanted the cells early in the animals' development when all the nutrients and signals they needed for differentiation were still there," says lead author Brenda Coles, a U of T laboratory technician working under the supervision of Professor Derek van der Kooy in the Department of Medical Genetics and Microbiology. "When their eyes fully developed, the human cells survived, migrated into the sensory part of the eye and formed the correct cells." The research has implications for future treatment of degenerative eye diseases such as retinitis pigmentosa and macular degeneration but that's still a long way off, says Coles. She, van der Kooy and their colleagues are now exploring whether retinal stem cells from healthy mice continue to develop into photoreceptor cells and RPE cells when transplanted to mice with diseased eyes.

Related chapters from BN: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 6317 - Posted: 10.26.2004

By SANDRA BLAKESLEE A type of self-renewing cell found in the adult human brain may have the potential to repair brain damage or disease, scientists reported yesterday. The cells, neural stem cells, have been known about for some time. But their function has been a mystery. Researchers theorized that the cells, as in rats and monkeys, generated new neurons that migrated to olfactory regions, helping maintain the sense of smell. But the study, reported yesterday in Nature, indicates that in humans, the stem cells behave differently. They form ribbons that produce different types of brain cells, including neurons. The new neurons do not migrate to olfactory regions, and they are not involved in the human capacity for smell, the study found. Copyright 2004 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 5: The Sensorimotor System
Link ID: 5014 - Posted: 02.20.2004

MADISON - Human neural stem cells, exposed in a lab dish to the steroid DHEA, exhibit a remarkable uptick in growth rates, suggesting that the hormone may play a role in helping the brain produce new cells, according to a new study published this week in the online editions of the Proceedings of the National Academy of Sciences (PNAS). The new work, conducted by a team of scientists at the University of Wisconsin-Madison, provides some of the first direct evidence of the biological effects of DHEA on the human nervous system, according to Clive Svendsen, the study's senior author and an authority on brain stem cells at UW-Madison's Waisman Center. "What we saw was that DHEA significantly increased the division of the cells," says Svendsen, a UW-Madison professor of anatomy and neurology. "It also increased the number of neurons produced by the stem cells, prompting increased neurogenesis of cells in culture."

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 8: Hormones and Sex
Link ID: 5004 - Posted: 02.19.2004

Scientists have identified a gene in the cerebral cortex that apparently controls the developmental clock of embryonic nerve cells, a finding that could open another door to tissue replacement therapy in the central nervous system. In a new study, the researchers found that they could rewind the clock in young cortical cells in mice by eliminating a gene called Foxg1. The finding could potentially form the basis of a new method to push progenitor cells in the brain to generate a far wider array of tissue than is now possible. The study, led by researchers at NYU School of Medicine, is published in the January 2, 2004 issue of Science magazine. "What we found was a complete surprise," says Gordon Fishell, Ph.D., Associate Professor in the Department of Cell Biology at New York University School of Medicine. "No one had believed that it was possible to push back the birth date of a cortical neuron. There is this central tenet governing the process of brain development, which says that late progenitor cells [forerunners of mature cell types] cannot give rise to cell types produced earlier in development," he explains.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 10: Biological Rhythms and Sleep
Link ID: 4745 - Posted: 01.04.2004

A group of researchers from The Scripps Research Institute (TSRI) and the Genomics Institute of the Novartis Research Foundation (GNF) have identified a small chemical molecule that controls the fate of embryonic stem cells. "We found molecules that can direct the embryonic stem cells to [become] neurons," says Sheng Ding, who recently completed his Ph.D. work at TSRI and is becoming an assistant professor in the chemistry department. Ding is the lead author on the study, which is described in an upcoming issue of the journal Proceedings of the National Academy of Sciences. "This is an important step in our efforts to understand how to modulate stem cell proliferation and fate," says Peter Schultz, Ph.D., TSRI professor of chemistry and Scripps Family Chair of TSRI's Skaggs Institute for Chemical Biology.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 3877 - Posted: 06.03.2003

STANFORD, Calif. - Scientists have finally laid hands on the first member of a recalcitrant group of proteins called the Wnts two decades after their discovery. Important regulators of animal development, these proteins were suspected to have a role in keeping stem cells in their youthful, undifferentiated state - a suspicion that has proven correct, according to research carried out in two laboratories at Stanford University Medical Center. The ability to isolate Wnt proteins could help researchers grow some types of stem cells for use in bone marrow transplants or other therapies. The gene coding for a protein usually reveals clues about how that protein will react in the lab and how best to isolate it from other molecules. The Wnts are unusual, however, because the way they behave in the lab differs from what the gene suggests. Roeland Nusse, PhD, professor of developmental biology at the School of Medicine and one of the first to isolate a Wnt (pronounced "wint") gene, reports how his lab members overcame these hurdles in the April 27 advance online edition of the journal Nature. "We found that the protein is modified, explaining why it has been difficult to isolate," said Nusse, who is also an investigator at the Howard Hughes Medical Institute. Although the protein's structure suggests it should dissolve easily in water, Karl Willert, PhD, a postdoctoral fellow in Nusse's lab, found that an attached fat molecule makes the protein shun water and prefer the company of detergents instead.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 3741 - Posted: 04.29.2003

By RICHARD PÉREZ-PEÑA In state capitols, universities, charitable foundations, hospitals and companies around the country, a scattershot movement is under way to counteract President Bush's 2001 order sharply limiting federal money for embryonic stem cell research. Lawmakers in New York, Maryland, Rhode Island, Tennessee, Washington and Massachusetts are considering bills authorizing embryonic stem cell research, according to advocates of the research and the National Conference of State Legislatures. Some bills go further, as one passed in California did last year when it authorized the use of state money to support research using embryonic stem cells, which scientists contend could eventually yield treatments for diabetes, Parkinson's, Alzheimer's, heart disease, cancer and other ailments. Mr. Bush and others who oppose such research say it is immoral because human embryos are destroyed when the cells are extracted. Copyright 2003 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 3563 - Posted: 03.16.2003

STANFORD, Calif. - Researchers in the Baxter Laboratory at Stanford University Medical Center have published new evidence showing that cells from the bone marrow might help repair or maintain cells in other tissues. In a paper in this week's online edition of the Proceedings of the National Academy of Sciences, the researchers describe finding chromosomes from a bone marrow transplant in the brain cells of transplant recipients. When people receive a bone marrow transplant after high-dose chemotherapy, some of the transplanted cells regenerate the blood-making cells that were destroyed. In past experiments in mice, Helen Blau, PhD, the Donald E. and Delia B. Baxter Professor of Pharmacology at the School of Medicine, found that cells from the transplant could also relocate to tissues throughout the body rather than being restricted to the bone marrow and blood. "Now we know that it can also happen in humans," said James Weimann, PhD, first author on the paper and a senior research scientist in Blau's lab.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 3405 - Posted: 02.05.2003

By NICHOLAS WADE A new stem cell institute being set up at Stanford University will study a wide variety of human diseases through two advanced but controversial techniques of cell manipulation. One is nuclear transfer, also used in cloning animals, and the other will involve generating new lines of human embryonic stem cells. The institute will be headed by Dr. Irving Weissman, a Stanford expert on the stem cells in the bone marrow that daily renew the red and white blood cells. An anonymous donor has provided $12 million to start the institute. Dr. Weissman said he intended to explore two promising new lines of inquiry made possible by embryonic stem cells. The first is to find out if stem cells and cancer cells may use the same genetic machinery to replicate themselves. Stem cells multiply freely to generate all the mature cells of the body, and though mature cells lose this ability cancer cells somehow regain it. Copyright The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 3165 - Posted: 12.12.2002