Embryonic stem cells with identical genomes grow into distinctive tissues, such as heart, bone, and brain. At one time, scientists believed the differences among cell types arose from various sets of genes switched on inside developing cells. Then, studies showed that adult neurons uniquely lack a protein that permanently turns off neuronal genes in the rest of the body's cells. Now, it turns out that precursor nerve cells contain that same repressive protein after all. In fact, the protein directs the complex network of genes that transforms an embryonic stem cell into a mature nerve cell, say Howard Hughes Medical Institute (HHMI) researchers. This new study, published in the May 20, 2005, issue of the journal Cell, may be among the first to track a set of genes from stem cell to differentiated neuron. It also reveals fundamental details of how stem cells retain developmental plasticity. "A single protein does it all," said Gail Mandel, HHMI investigator at the State University of New York at Stony Brook. "It keeps the genes totally off in non-neuronal tissues, such as skin, where you don't dare express a neuronal gene. But it also allows the full elaboration of the neuronal phenotype from the precursor cell."

Keyword: Development of the Brain
Link ID: 7377 - Posted: 05.20.2005

A diet rich in vitamin E could protect against Parkinson's disease, believe researchers. Good sources of vitamin E include green leafy vegetables, nuts and vegetable oils. A study in Lancet Neurology pooled available data and found people who ate plenty of these foods in their diet were far less likely to develop Parkinson's. The authors said it was impossible to tell if supplements would do the same. Dr Mayhar Etminan, from Queen's University in Canada, and colleagues scrutinised eight studies published between 1966 and 2005 looking at the effects of vitamins E and C, and the nutrient beta carotene. Both moderate and high doses of vitamin E appeared to reduce the risk of Parkinson's. Neither vitamin C or beta carotene had a similar effect, however. Dr Etminan said: "Our data suggest that diets rich in vitamin E protect against the development of Parkinson's disease. But he added: "No definite conclusions regarding the benefits of supplemental vitamin E can be made. "Given that these data are observational, confirmation from well-designed randomised controlled trial is necessary before suggesting changes in routine clinical practice." A spokesman from the Parkinson's Disease Society agreed. He cautioned against people rushing out and buying lots of vitamin E supplements to ward of Parkinson's. In high doses, vitamin E can be toxic. (C)BBC

Keyword: Parkinsons
Link ID: 7376 - Posted: 05.20.2005

In studies with rats, researchers have distinguished a burst of the brain chemical dopamine from a reward-related brain region that is associated with anticipating the delivery of cocaine. The finding, publishing in the May 19 issue of Neuron, reveals the brain signal that likely underlies the fundamental motivation to obtain such drugs, said the scientists. Thus, the finding may give clues to the basic brain mechanism that causes drug-seeking behavior, they said. In their experiments, researchers led by Regina M. Carelli of the University of North Carolina in Chapel Hill used infinitesimally small recording electrodes in the brains of rats to detect the release of the neurotransmitter dopamine from the region called the nucleus accumbens. Almost all drugs of abuse cause release of dopamine from this region--part of the brain's reward system. Such release triggers neurons in other brain regions, generating the pleasurable sensation associated with taking such drugs. The researchers first taught rats to self-administer cocaine by pressing a lever when a light in their cage came on. They next extinguished this behavior by substituting saline solution for the cocaine. Finally, they reinstated the lever-pressing behavior by restoring the cocaine. Their measurements revealed three distinct types of transient bursts of dopamine from the nucleus accumbens. One dopamine signal that occurred immediately before a lever press continued to occur, even after the rats ceased to receive cocaine. This signal, concluded the researchers, could reflect the motivation to obtain the drug.

Keyword: Drug Abuse
Link ID: 7375 - Posted: 05.20.2005

In a finding that holds lessons for restaurateurs and advertisers, researchers have found that visual words can influence the perception of smells--with pleasant words influencing olfactory brain regions to perceive an odor as pleasant. The research is publishing in the May 19 issue of Neuron. In their experiments, researchers led by Edmund T. Rolls of the University of Oxford presented subjects with a cheddar cheese odorant and showed them labels that read either "cheddar cheese" or "body odor." They found that the subjects rated the odor significantly more pleasant when it was labeled "cheddar cheese" than "body odor." They then scanned the subjects' brains using functional magnetic resonance imaging (fMRI) during the presentation of labels and odors to explore which brain regions were activated. They also analyzed brain activity when the subjects were presented with clean air labeled either "cheddar cheese" or "body odor." The widely used analytical technique of fMRI uses harmless magnetic fields and radio waves to measure blood flow in regions of the brain, which reflects brain activity. The researchers found that labeling the odor "cheddar cheese" produced an activation in a specific part of the brain region that processes olfactory information. Clean air labeled as "cheddar cheese" activated the same area, but to a lesser extent. The "body odor" label, however, did not produce activation in this area, either with the cheddar cheese odor or clean air.

Keyword: Chemical Senses (Smell & Taste); Language
Link ID: 7374 - Posted: 05.20.2005

By Susan S. Lang ITHACA, N.Y. -- In mammals, sperm from the male determines the sex of the offspring. In birds, however, it is the female's sex chromosome that determines offspring sex. Now, Cornell University researchers think they understand the mechanism that several bird species use to bias the sex ratios of their offspring toward female. By experimenting with domestic chickens, they have determined that the presence of higher-than-normal levels of the hormone progesterone during the first meiosis -- the cell division that divides the sex chromosomes and genetically determines the sex of an offspring -- produces significantly more females. "For years, behavioral biologists have been trying to figure out how the females of a few species, such as the Seychelles warbler, the zebra finch and tree swallow, adaptively manipulate the sex of their offspring before an egg is laid," says Stephanie Correa, a doctoral student in neurobiology and behavior at Cornell and the lead author of the study that was posted online recently in The Royal Society's Biology Letters (Vol. 1, 2005). "Most investigators have looked primarily at testosterone, but we decided to look at progesterone, the major hormone produced by the female bird's preovulatory follicle."

Keyword: Sexual Behavior
Link ID: 7373 - Posted: 05.18.2005

By PAUL LUKAS ROBERT WEINSTOCK doesn't remember the accident. "It was Oct. 7, 2003, and I was going to get a prescription from my doctor," he recalled recently. "It was just two blocks away, but I was running late, so I took my bicycle. I'd only been biking for about five seconds when I turned a corner. The next thing I remember is waking up in the hospital." Mr. Weinstock, a 37-year-old illustrator and children's book author who lives in Greenwich Village, soon learned that he had been hit by a truck, resulting in a broken arm, hearing loss in one ear, spinal fluid leakage and a fractured skull. He spent two weeks in the hospital, where he underwent two spinal taps and skull surgery. Given the gravity of his injuries, Mr. Weinstock didn't worry too much about how his food was tasting. "My mother was bringing me soup from some fancy market," he said, "and I realized at some point that it all tasted like chicken fat, schmaltz. I didn't say anything, because I figured there was just something off with the food." But after he left the hospital, he realized the problem was wide-ranging. "Coffee smelled a bit rank, anything with garlic tasted horrible - and I always loved garlic!" he said. "Then I had mint chocolate chip ice cream, one of my favorite foods, and it tasted really chemical-y." Copyright 2005 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 7372 - Posted: 05.18.2005

Robin McKie, science editor Mike Robins is a man redeemed. Thanks to pioneering surgery, the debilitating effects of Parkinson's disease that were wrecking his life are now under tight control. With the flick of a switch, he can turn off the uncontrollable tremors that stopped him holding down a job, having a social life or even getting to sleep. Not surprisingly, Robins reckons he is lucky to be fit and alive. Others are not so sure. At a recent public meeting to discuss a proposed animal research centre in Oxford, 63-year-old Robins was jeered and ridiculed when he tried to show how surgery, perfected through animal experiments, had transformed his life. 'I was bayed at,' said Robins, a retired naval engineer from Southampton. 'Several hundred people were shouting. Some called out "Nazi!", "bastard!" and "Why don't you roll over and die!" I tried to speak, but was shouted down. It was utterly terrifying.' The attack has shocked even hardened observers of vivisection debates. 'I have seen many unpleasant things at these debates, but to scream at a middle-aged man with Parkinson's disease and then tell him he deserved to die is the worst I have observed,' said Simon Festing, director of the Research Defence Society, which defends the scientific use of animals for experimentation. © Guardian Newspapers Limited 2005

Keyword: Animal Rights; Parkinsons
Link ID: 7371 - Posted: 06.24.2010

PITTSBURGH,– Women who take antidepressants during the final trimester of pregnancy through delivery increase the risk of "neonatal behavioral syndrome," a constellation of symptoms and behaviors largely related to drug withdrawal or side effects, University of Pittsburgh researchers conclude in a review of medical literature. Such findings reveal an additional challenge for clinical management of depression during pregnancy, Eydie Moses-Kolko, M.D., assistant professor of psychiatry at the University of Pittsburgh School of Medicine, and her colleagues write in the May 18 issue of the Journal of the American Medical Association. "The FDA and drug manufacturers recently agreed to label revisions for antidepressants known as selective serotonin reuptake inhibitors. Now the label for these drugs includes information about potential adverse effects to newborns if the drug is taken late in pregnancy," said Dr. Moses-Kolko, who also is on staff with the Women's Behavioral HealthCARE program of the Western Psychiatric Institute and Clinic of the University of Pittsburgh Medical Center. "Late exposure was associated with increased risk for a range of complications including jitteriness, stiffened muscle tone, irritability, respiratory distress and feeding problems." While most cases of neonatal behavioral syndrome are mild and generally resolve in about two weeks, a number are severe enough to require neonatal intensive-care unit (NICU) hospitalization. "Newborns exposed to antidepressants late in pregnancy had more than twice the risk of admission to a special-care nursery as those exposed only early in pregnancy," Dr. Moses-Kolko said, adding that late-exposed newborns also had twice the risk of respiratory complications – some critical.

Keyword: Depression; Development of the Brain
Link ID: 7370 - Posted: 06.24.2010

Chronic stress can be harmful - to your health and also to your brain, according to researchers at the Douglas Hospital Research Center. Their findings, published in a recent issue of Psychoneuroendocrinology, show increased stress hormones lead to memory impairment in the elderly and learning difficulties in young adults. "Stress has become more commonplace and accepted in our everyday lives," says Sonia J. Lupien, PhD, lead author and director of the Laboratory of Stress Research at the Douglas. "Many studies show the negative impact of stress on physical health such as blood pressure, heart disease etc, but few address the effects on mental health. Our studies look directly at the long term effects of stress, or stress hormones, on brain function." Lupien and colleagues measured the stress hormone, cortisol, in older adults over a period of three to six years. Their findings showed that individuals who had continuous high levels of cortisol, performed poorly on memory tests and had a notably smaller hippocampus, the part of the brain responsible for learning and memory. "This study clearly shows the negative effects of long-term stress," says Lupien. "This explains why some older adults show poor brain function while others perform very well. Perhaps, through early interventions, we can modify the cortisol levels and enhance brain function of the at-risk individuals. "

Keyword: Stress
Link ID: 7369 - Posted: 05.18.2005

THE risk of autism in twins appears to be related to the month they are born in. The chance of both babies having the disorder is 80 per cent higher for January births than December births. This was one of the many findings presented at the conference in Boston last week. It typifies the problems with many autism studies: the numbers are too small to be definitive - this one was based on just 161 multiple-birth babies - and even if the finding does stand up, it raises many more questions than it answers. For instance, is infection during pregnancy to blame? Or another environmental factor that varies with the season? Is it the birth date that is important, or the date of conception? While it is now clear that autism is a complicated combination of genetic and environmental factors, no one knows exactly what these environmental effects are and which genes they might be interacting with to cause autism. "We clearly have a daunting task ahead of us," Craig Newschaffer of the Johns Hopkins School of Public Health in Baltimore, Maryland, and a member of the birth-date study team, told the conference. "We have had slower-than-hoped for progress finding autism genes, and now we see an increased focus on the environment in autism." Based on twin studies, the consensus is that, depending on how you define autism, between 60 and 90 per cent of cases are genetic in origin. And although progress has been slow, geneticists are homing in on some of the genes involved. © Copyright Reed Business Information Ltd

Keyword: Autism
Link ID: 7368 - Posted: 06.24.2010

A difficult birth and a family history of mental illness may increase the risk of autism, say US researchers. The Centers for Disease Control and Prevention team base their findings on nearly 700 Danish children with autism. More than 500,000 people in the UK are thought to be affected by autism spectrum disorders, which limit their ability to develop friendships and understand other's emotional feelings. The latest study findings appear in the American Journal of Epidemiology. Experts have already noted that the condition has a strong genetic component. However, the number of children with autism appears to be increasing more than expected for a genetic disorder. Toxins, diet, viruses and other pathogens have been suggested, though there is no strong evidence for any of these. Research has also linked the condition with a variety of conditions affecting brain development which occur before, during, or very soon after birth. The CDC team, working with colleagues at the University of Aarhus in Denmark, found children with autism were more likely to have had difficult births than other children of the same age. This included breech births, premature births and problems immediately after delivery. Parental psychiatric history was associated with the highest independent risk of autism. (c)bbc

Keyword: Autism; Development of the Brain
Link ID: 7367 - Posted: 05.17.2005

Evolutionary scientists have never had difficulty explaining the male orgasm, closely tied as it is to reproduction. But the Darwinian logic behind the female orgasm has remained elusive. Women can have sexual intercourse and even become pregnant - doing their part for the perpetuation of the species - without experiencing orgasm. So what is its evolutionary purpose? Over the last four decades, scientists have come up with a variety of theories, arguing, for example, that orgasm encourages women to have sex and, therefore, reproduce or that it leads women to favor stronger and healthier men, maximizing their offspring's chances of survival. But in a new book, Dr. Elisabeth A. Lloyd, a philosopher of science and professor of biology at Indiana University, takes on 20 leading theories and finds them wanting. The female orgasm, she argues in the book, "The Case of the Female Orgasm: Bias in the Science of Evolution," has no evolutionary function at all. Rather, Dr. Lloyd says the most convincing theory is one put forward in 1979 by Dr. Donald Symons, an anthropologist. That theory holds that female orgasms are simply artifacts - a byproduct of the parallel development of male and female embryos in the first eight or nine weeks of life. Copyright 2005 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 7366 - Posted: 05.17.2005

On Saturday evening, March 10, 2001, my 17-year-old son, Will, returned from an evening of bowling with friends. He sat at the kitchen table and told me he'd had a great night: He bowled over 100 twice in a row, he said, and then he, his girlfriend and cousin went to a pizza joint afterward. He appeared cheerful and light. "You seem to be feeling a lot better, Will," I told him. It wasn't a casual remark; Will had been diagnosed with major depression in the fall of 2000, and after an agonizing and worrisome few months, he appeared to be shaking it off. I thought the latest medications were finally beginning to take effect. Or maybe it was just the passage of time, but by all markers, he looked as though he was genuinely on the mend. "Yeah, Mom, I think I am better. No, really, I think I'm okay." I kissed him on the forehead and went to bed buoyed by our exchange. For the first time in months I felt confident that we, that he, had turned the corner. Will watched the basketball playoffs with his stepsister and her friends for an hour or so. He then went to his bedroom, wrote out four suicide notes and at 3 a.m. ingested 100 times the normal dose of the sedative antidepressant Remeron, washed down with a bottle of Snapple Iced Tea. © Copyright 1996-2005 The Washington Post Company

Keyword: Depression
Link ID: 7365 - Posted: 06.24.2010

HAVING problems performing in the sack? Take Viagra. Got the jitters before that important presentation? Try beta blockers. Need to stay awake to finish that assignment? Pop a Provigil pill. For those prepared to pay, the growing list of "lifestyle drugs" is shifting the boundaries of what bodies and minds are capable of. Now a small clinical trial of the class of experimental drugs known as ampakines suggests these brain-boosters are destined to blur that line still further by offering improved memory. The success of the unrelated drug Provigil (also called modafinil) has proved there is a huge market for drugs that can improve mental performance. The US Food and Drug Administration has approved it for treating narcolepsy, sleep apnoea - disrupted breathing during sleep - and the sleepiness caused by shift work. But it is widely taken "off-label" by healthy people to stay awake and alert. Sales of the drug, produced by Cephalon of West Chester, Philadelphia, have more than doubled since 2002, and continue to skyrocket (see Graphic). Some may feel uncomfortable with the increasing availability of such pharmaceutical pick-me-ups, but others see them as no different from performance aids such as palmtop organisers. "Stimulating your brain with a reminder on a Blackberry doesn't seem that different to me from stimulating your brain with a drug," says Arthur Caplan, a bioethicist at the University of Pennsylvania in Philadelphia. © Copyright Reed Business Information Ltd.

Keyword: Learning & Memory
Link ID: 7364 - Posted: 06.24.2010

According to the Centers for Disease Control, tobacco use remains the leading preventable cause of death in the United States, causing more than 440,000 deaths each year and resulting in an annual cost of more than $75 billion in direct medical costs. The substance that makes cigarettes addictive is nicotine, which enhances the release of a neurotransmitter called dopamine, which is associated with the pleasure people get from eating, sex, and drugs. But Henry Lester, a neuroscientist at the California Institute of Technology, says nailing down exactly how nicotine behaves in the brain has been difficult. "We have known for, oh goodness, 450 years that nicotine does act on the body," he says. "But it's been unclear until the present which particular molecules it does act on. The question is, which of the various—and there are more than a dozen nicotine receptors in the body—is the one responsible for nicotine addiction?" Lester and his team believe they may have come closer to the answer. The brain has more than a dozen molecules—each with several "subunit" proteins—that respond to nicotine. These "nicotinic receptors" might act together or independently to cause addiction. Lester and his colleagues picked just one of them—the subunit alpha4 receptor—and genetically enhanced it in mice, creating "hypersensitive knock-in" mice. (C) ScienCentral, 2000-2005.

Keyword: Drug Abuse
Link ID: 7363 - Posted: 06.24.2010

Neuroscientists have found a drug for traumatic brain injury that appears to work better than any current treatment. Rats that were given the drug following a concussive brain injury had a near-complete recovery, while untreated rats suffered significant brain damage. In the days after a concussion, damaged brain tissue responds in two main ways. Neurons self-destruct in a process called apoptosis, and glial cells, some of which support and surround neurons, divide, causing inflammation and scar tissue. These processes leave a hole surrounded by a glial scar, resulting in loss of motor and cognitive function. To find a way to prevent this damage from occurring, neuroscientist Simone Di Giovanni and others in Alan Faden's lab at Georgetown University in Washington, D.C., and at the Universita di Pavia in Italy used gene expression arrays to determine which genes become activated in damaged brain tissue after a concussion. They found that cell cycle genes involved in cell division set off both glial proliferation and neuronal apoptosis. The researchers then injected an experimental drug called flavopiridol, which inhibits cell cycle enzymes, into the cerebral fluid of rats 30 minutes after they were given a moderately severe concussion. Rats that were not treated developed a large hole in their brains visible with magnetic resonance imaging (MRI). But in the treated rats, there was scarcely a trace of brain damage on MRI after 4 weeks, and they performed as well as normal rats on motor and cognitive tests, while brain damaged rats did not. "This degree of protection was really remarkable. Lots of drugs have shown neural protection in similar models, but they haven’t provided anywhere near this level of benefit," says Faden, whose group's report appears online this week in the Proceedings of the National Academy of Sciences. Copyright © 2005 by the American Association for the Advancement of Science.

Keyword: Brain Injury/Concussion
Link ID: 7362 - Posted: 06.24.2010

Providence, RI – Leading researchers in colic and infant development say that a simple analysis of babies' cries can provide a window into their neurological and medical status. In a research review in the current issue of Mental Retardation and Developmental Disabilities, Linda LaGasse, PhD, and Barry Lester, PhD, with the Bradley Hasbro Children's Research Center (BHCRC) and Brown Medical School looked at previous studies that analyzed the acoustics of a baby's cry. The authors cite the characteristics of a cry that can indicate problems in a baby's nervous system, as well as sudden infant death syndrome (SIDS). In addition, they cite the importance of how parents react to their squalling offspring. "The cry signal has enormous potential diagnostic value; for example, very high pitched cries can tell us that something may be wrong with the infant, so the cry signal can be an early warning that leads to further neurological testing," says LaGasse. Overall, studies have repeatedly shown that infants at medical risk (like premature babies), and infants who have been exposed to lead or drugs, cry at a higher and more variable frequency than normal, but at lower amplitude, and with short utterances. These types of cry signals point toward a capacity problem in the respiratory system as well as an increased tension and instability of neural control of the vocal tract.

Keyword: Language; Development of the Brain
Link ID: 7361 - Posted: 06.24.2010

— Surges of solar activity may cause whales to run aground, possibly by disrupting their internal compasses, German scientists suggest. University of Kiel researchers Klaus Vaneslow and Klaus Ricklefs looked at sightings of sperm whales found beached in the North Sea between 1712 and 2003. They then compared this record with another set of historical data — astronomers' observations of sunspots, which is an indicator of solar radiation. More whale strandings occurred when the sun's activity is high, they found. The sun experiences cycles of activity which range from eight to 17 years, with 11 years being the average. Short cycles are linked with periods of high energy output, while long cycles are believed to be low energy. Changes in levels of solar radiation have a big effect on Earth's magnetic field. The most notable events are bouts of highly-charged particles, called solar flares, that cause the shimmering Northern Lights, also called aurorae, in the magnetic fields in polar regions. Big solar flares can also disrupt telecommunications and power lines and knock out delicate electronic circuitry on satellites. Copyright © 2005 Discovery Communications Inc.

Keyword: Animal Migration
Link ID: 7360 - Posted: 06.24.2010

Mark Peplow Our ability to learn language is already on the wane by our third year of life, according to a study of profoundly deaf children given cochlear implants to restore some of their hearing. The research supports the widely held belief that there is a 'sensitive period' for language learning, during which the capacity to acquire vocabulary and grammar is heightened. "But I was surprised we found evidence that this sensitive period occurs so early in life," says Mario Svirsky, an acoustic engineer from the Indiana University School of Medicine in Indianapolis, who led the study. Svirsky and his colleague Rachael Frush Holt looked at 96 children who had received implants during their first four years of life. The implants, which are surgically inserted in the ear, convert sound into electrical signals that the brain can interpret, allowing many deaf people to hear. The team then tested the children's language development and speech comprehension every few months for several years after the procedure. Svirsky found that the rate of language learning was greatest for those given implants before they turned two. This was measured with the widely used Reynell Developmental Language Scales, which test a child's vocabulary and understanding of grammar. Children given implants at three or four years of age acquired language skills more slowly, although Svirsky stresses that these children still benefited from the devices. ©2005 Nature Publishing Group

Keyword: Language; Hearing
Link ID: 7359 - Posted: 06.24.2010

An extract from a plant known in the US as “the vine that ate the South” may help reduce alcohol consumption in heavy drinkers, a small-scale study suggests. Previous research has shown that kudzu plant extract has helped reduce alcohol drinking in rats and hamsters, but this is the first study to show the effect in humans. The plant was introduced to the US to combat soil erosion but has now become a persistent weed. In the study, people who were given kudzu extract for seven days drank about one beer less in a monitored 1.5-hour drinking session than people who took the placebo, say researchers at McLean Hospital, Harvard Medical School and New England Research Institutes in Massachusetts, US. Those treated also drank more slowly. The 14 subjects were all heavy drinkers, consuming an average of 25 alcoholic beverages per week, but none of them were alcohol dependent or had a family history of alcoholism. The experimental group took two 500-milligramme kudzu capsules three times a day. Then they came into a laboratory which simulated a living room, with a television, stereo and bookshelf. A small kitchen was stocked with their favourite beer. Between swigs, the subjects were required to put their beer onto an end table with a built-in scale so researchers could track exactly how much beer they were drinking. © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse
Link ID: 7358 - Posted: 06.24.2010