When Ronald Reagan announced in 1994 that he was suffering from Alzheimer's, he became a prominent face of a disease which afflicts about 4.5 million Americans. Like many Alzheimer's patients, Reagan lived a long time with the disease; a person with Alzheimer's will live an average of eight years and as many as 20 years or more from the onset of symptoms, as estimated by relatives. Reagan lost his battle with Alzheimer's on Saturday, June 5, after ten years of suffering from the debilitating effects of the disease. Today, we're still not sure what causes it. "We think Alzheimer's has several causes, although the actual cause is unknown," says Paul Thompson of the UCLA Laboratory for Neuroimaging. "You might be at genetic risk for it, or there might be different chemicals in the body that actually control your risk for getting Alzheimer's." Researchers have theorized that fibrous masses of protein in the brain play a role in Alzheimer's disease. Called amyloids, these plaques block nerve communication. What's more, scientists have had trouble finding a way to dissolving these plaques once they form. "They're so tough," says Susan Lindquist, director of the Whitehead Institute for Biomedical Research. "They're resistant to detergents, they're resistant to salt, they're resistant to freezing or boiling, they're resistant to organic solvents, even." © ScienCentral, 2000-2004.

Keyword: Alzheimers
Link ID: 5616 - Posted: 06.24.2010

In the brain, nerve cells, or neurons, grow new connections, which resemble branches on a tree. These branches send and receive signals, and their growth is vital to normal brain function; the more branches there are, the more sites by which a neuron can send and receive information. "While you're an adult, your brain doesn't just stop growing and doesn't just stop making new connections. It actually forms new connections all the time," says Bonnie Firestein, professor of cell biology and neuroscience at Rutgers University. "We know that when you're learning something, you have new connections made. So, the brain is constantly growing and constantly changing." Firestein has found that a brain chemical called cypin helps nerve cells sprout new branches of communication, and the more cypin you have, the more branches you have. "We know that if you decrease cypin, in our system, you have a lower amount of branches," she explains. "So, right now…we just know that cypin is really important for making the correct number of branches, and that if you increase cypin you get more branches, and that it's been shown that more branches generally corresponds to learning and memory. When you're learning, you're making the nerve cells active, you're having increases in cypin, and then you're having more branches or more wiring so that you can learn." © ScienCentral, 2000-2004.

Keyword: Development of the Brain
Link ID: 5615 - Posted: 06.24.2010

Would you know what species to mate with if you'd grown up alone and didn't have a mirror? That's the challenge faced by the Australian brush turkey, which hatches alone in a warm mound of rotting leaf litter. Now, with the help of remote-control robots made from toy car motors and the skins of dead chicks, a research team has gleaned the first insights into how the brush turkey recognizes its own kind. Most birds learn to identify their own species by "imprinting" on their parents while their nervous system is still at an impressionable stage, but for brush turkeys (family Megapodiidae) that's not an option. Females lay eggs in a compost heap built by the male, then leave the incubation up to the heat from decomposition. That means the chicks can't imprint. "It's the most nonavian life history you can get among creatures that are still feathered and lay hard-shelled eggs," notes Mark Hauber, a behavioral ecologist at the University of Auckland in New Zealand. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Sexual Behavior; Development of the Brain
Link ID: 5614 - Posted: 06.24.2010

By Mari N. Jensen When algae find themselves in hot water, the normally asexual organisms get all stressed out and turn sexual. Blame it on the free radicals, says a team of researchers. Colonies of the multicellular green alga Volvox carteri exposed to temperatures of 111 degrees Fahrenheit (42.5 degrees Celsius) had twice the amount of free radicals, oxidants that can damage biological structures, as unheated colonies. High levels of oxidants within their cells activated the algae's sex-inducer gene, the researchers report. Then the fun starts. The sex-inducer gene promotes the production of the sex-inducer, a pheromone the colony releases to guarantee willing mating partners. "We're the first to show that oxidants are responsible for sex in this organism," said UA professor Richard E. Michod, head of UA's department of ecology and evolutionary biology and a coauthor on the research. "This is the first demonstration that stress turns on sex-inducer genes." © 2004 Arizona Board of Regents

Keyword: Sexual Behavior; Evolution
Link ID: 5613 - Posted: 06.24.2010

A new study indicates that postnatal exposure to thimerosal, a mercury preservative commonly used in a number of childhood vaccines, can lead to the development of autism-like damage in autoimmune disease susceptible mice. This animal model, the first to show that the administration of low-dose ethylmercury can lead to behavioral and neurological changes in the developing brain, reinforces previous studies showing that a genetic predisposition affects risk in combination with certain environmental triggers. The study was conducted by researchers at the Jerome L. and Dawn Greene Infectious Disease Laboratory at the Mailman School of Public Health, Columbia University. Over the past 20 years, there has been a striking increase--at least ten-fold since 1985--in the number of children diagnosed with autism spectrum disorders. Genetic factors alone cannot account for this rise in prevalence. Researchers at the Mailman School, led by Dr. Mady Hornig, created an animal model to explore the relationship between thimerosal (ethylmercury) and autism, hypothesizing that the combination of genetic susceptibility and environmental exposure to mercury in childhood vaccines may cause neurotoxicity. Cumulative mercury burden through other sources, including in utero exposures to mercury in fish or vaccines, may also lead to damage in susceptible hosts. Timing and quantity of thimerosal dosing for the mouse model were developed using the U.S. immunization schedule for children, with doses calculated for mice based on 10th percentile weight of U.S. boys at age two, four, six, and twelve months.

Keyword: Autism
Link ID: 5612 - Posted: 06.09.2004

Gene therapy succeeds in mice with brain disease. ERIKA CHECK Gene therapy could ease the symptoms of some devastating brain disorders, according to evidence presented to US conference last week. Many neurodegenerative diseases are caused when the brain makes mutant proteins that build up in the brain, causing gradually worsening symptoms. These brain-wasting diseases are devastating and incurable. They include Huntington’s disease, which affects around 250,000 people in the United States. Beverley Davidson of the University of Iowa in Iowa City and her colleagues hope that gene therapy will help treat such diseases. The approach involves trying to correct genetic abnormalities by injecting an animal or person with corrective sequences of DNA or RNA. The researchers tested their therapy in mice with a disorder that mimics a disease called spinocerebellar ataxia type 1, which leaves sufferers progressively less able to walk. The therapy eliminated pockets of damaged brain tissue from the mice and corrected the physical symptoms of the disease. © Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Huntingtons
Link ID: 5611 - Posted: 06.24.2010

— Muscular dystrophy is a group of genetic diseases characterized by progressive muscle degeneration. Working with mice with a type of the disease, researchers have found that by expressing an enzyme that attaches sugar molecules to a protein essential for proper muscle structure, they can restore normal muscle function. Interestingly, the scientists found evidence of similar benefits when they expressed the protein, known as LARGE, in cells from patients with similar types of muscular dystrophies with distinct gene defects, suggesting that this approach may have clinical benefits for patients with the debilitating disease. The study, led by Howard Hughes Medical Institute investigator Kevin P. Campbell at the University of Iowa College of Medicine, was published online in the journal Nature Medicine on June 6, 2004. Campbell's co-authors on the paper were from the University of Iowa, the University of Toronto, Uppsala University in Sweden, and the National Center of Neurology and Psychiatry in Tokyo. The study complements additional work by Campbell and colleagues from the Scripps Research Institute in California, the California Pacific Medical Center Research Institute, and Uppsala University, which elucidated the critical role of LARGE in the processing of a protein required to link muscle cells to their surrounding matrix. This work was published in an advance online publication of Cell on June 3, 2004. ©2004 Howard Hughes Medical Institute

Keyword: Muscles; Movement Disorders
Link ID: 5610 - Posted: 06.24.2010

By GINA KOLATA Ask anyone: Americans are getting fatter and fatter. Advertising campaigns say they are. So do federal officials and the scientists they rely on. But Dr. Jeffrey Friedman, an obesity researcher at Rockefeller University, argues that contrary to popular opinion, national data do not show Americans growing uniformly fatter. Instead, he says, the statistics demonstrate clearly that while the very fat are getting fatter, thinner people have remained pretty much the same. Let it be said that Dr. Friedman, a Howard Hughes Medical Institute investigator and the discoverer of the gene for leptin, a hormone released by fat cells, is not fat. He is tall and gangly, with the rumpled look of an academic scientist. As an obesity researcher, he might be expected to endorse the prevailing view that obesity in this country is out of control. But Dr. Friedman said he was outraged by the acceptance of what he sees as a hurtful myth, one that encourages people to believe that if you are fat, it is your fault. Copyright 2004 The New York Times Company

Keyword: Obesity
Link ID: 5609 - Posted: 06.08.2004

By BENEDICT CAREY Moody teenagers who visit therapists for help often wonder how useful all that talk about feelings and emotions really is. Now, many doctors are asking the same thing. Last week, researchers presented findings from a large government-financed study showing that depressed teenagers were much more likely to improve by taking Prozac than by undergoing a standardized form of talk treatment, cognitive behavior therapy. For parents desperately trying to help a depressed teenager, the study may appear to make their choices even more confusing. Already worried by Food and Drug Administration warnings that antidepressants can be dangerous for a small number of children and adolescents, parents now face the news that the best alternative, talk therapy, may be a waste of time. Yet experts say the results of the study are more complicated, and less discouraging, than they might seem at first glance. The study, to be published this year, offers some reassurance that the drugs are probably helping. At the same time, it makes clear that psychotherapy does have a place. Although statistically, therapy alone was no better than a placebo, it did lift depression in 43 percent of the teenagers studied, compared with 35 percent given dummy pills. Almost three-quarters of the adolescents who combined talk and drug treatments improved significantly, and the psychotherapy appeared to reduce the risk of suicide. Copyright 2004 The New York Times Company

Keyword: Depression; Development of the Brain
Link ID: 5608 - Posted: 06.08.2004

Because we live in a visually complex world, one of the major tasks of vision is to resolve ambiguous information into a stable image of our surroundings. By presenting subjects with differing versions of visually ambiguous images, researchers have identified the factors that are important for perceptual stabilization, a process that allows the visual system to overcome conflicting information and maintain a steady perception of an image. Visual perception is generally accurate and stable. However, when a visual stimulus provides conflicting or insufficient information, perception can be bi-stable or even multi-stable – that is, the way an image is perceived by the viewer can change or switch back and forth over time. By studying the visual system's solution when faced with such ambiguous conditions, Dr. Xiangchuan Chen from the University of Science and Technology of China and Dr. Sheng He from the University of Minnesota sought to tease out clues to the underlying mechanisms of visual perception. Earlier research had shown that perception can be stabilized when the ambiguous visual stimuli were presented intermittently. Memory of the recent perceptual experience had been proposed to explain this stabilization effect. But the nature of this "perceptual memory" has remained unclear.

Keyword: Vision
Link ID: 5607 - Posted: 06.24.2010

A meticulous series of experiments – and the fortuitous use of a vacuum cleaner – lead to breakthrough new insight on the genetic basis of epilepsy. Circadian rhythms -- the normal ups and downs of body rhythms – help organize physiological processes into a 24 hour cycle, affecting everything from body temperature, hormone levels and heart rate, to pain thresholds. Scientists have now discovered that the combined deletion of three circadian genes, encoding the PAR bZip transcription factor protein family, results in accelerated aging and severe epilepsy in mice. Owing to the roughly 95% identity of PAR bZip proteins between mice and humans, it is anticipated that PAR bZip mutations may also underlie some forms of human epilepsy. A copy of this important new study is being released in advance of its June 15th publication date by the journal Genes & Development (http://www.genesdev.org). "The objective of the study was to assign physiological functions to the small family of PAR bZip transcription factors," explains Dr. Ueli Schibler, principal investigator of the study and in whose lab the first PAR bZip transcription factor was found nearly 15 years ago. The PAR bZip transcription factor family is composed of three proteins (DBP, HLF and TEF), all of which display distinct patterns of circadian accumulation: In tissues with high amplitudes of circadian clock gene expression (like the liver), PAR bZip protein levels change up to 50-fold throughout the day. However, in the brain, where clock gene expression varies little, PAR bZip protein levels barely change.

Keyword: Epilepsy; Biological Rhythms
Link ID: 5606 - Posted: 06.24.2010

ST. PAUL, Minn. – Despite limited evidence of effectiveness, many epilepsy and multiple sclerosis patients believe marijuana is an effective treatment and are actively using it, according to two Canadian studies published in the June 8 issue of Neurology, the scientific journal of the American Academy of Neurology. Multiple sclerosis patients in Halifax, Nova Scotia, and epilepsy patients in Edmonton, Alberta, recently participated in a questionnaire and a telephone survey, respectively, regarding patterns, prevalence and perceived effects of marijuana use. Results of these surveys may raise more questions than they answer. In the study of epilepsy patients from the University of Alberta Epilepsy Clinic, 136 subjects responded to the phone survey. Of these, nearly half had used marijuana in their lifetime; one in five had used marijuana in the past year; 20 (15 percent) had used in the past month; 18 (13 percent) used more than 48 days per year; and 11 (8 percent) used more than half the days of the year. Four patients were actually considered marijuana dependent. Odds of frequent marijuana use were eight times greater for patients with frequent seizures and 10 times greater for those who had had epilepsy for at least five years.

Keyword: Drug Abuse; Pain & Touch
Link ID: 5605 - Posted: 06.24.2010

BY TOM SIEGFRIED (KRT) - Some scientists wonder how smart it is to enhance how smart people are. At first glance, it seems like a no-brainer. Smarts are in short supply in the world today, and you'd be tempted to think the more, the better. On the other hand, some ostensibly smart people do some pretty stupid things. Making people smarter might have its dumb side. At the very least, the issue calls for some thoughtful consideration, many neuroscientists and bioethicists believe. Society may soon have to face some tough choices about whether the mental equivalent of Viagra poses more risks than benefits. In the past, the question has been moot, because nobody knew how to enhance mental function, anyway. Even though the "smart pill" industry has become big business, most studies don't show such pills to be very effective. © 2004, The Dallas Morning News.

Keyword: Learning & Memory
Link ID: 5604 - Posted: 06.24.2010

You know the location of your cousin’s house. How to prepare a grilled cheese sandwich. When to wear rain boots. How to calculate a tip for the pizza delivery guy. The list goes on and on. Thanks to memory you can easily navigate life. Many people, however, are not so fortunate. Alzheimer’s disease (AD), for example, which affects some 4 million older Americans, destroys memory and thinking capabilities. Individuals with AD may have trouble recalling addresses, major events, or the name of the president. Making meals and managing finances can become difficult. Over time problems with memory and thinking get even worse. Speech abilities diminish. Dressing and other simple tasks require assistance. For years, the biological basis of memory was unclear, which hindered the search for treatments to improve memory and thinking in those with disorders like AD. Now, a series of recent discoveries have advanced the field. The studies uncover several brain components that appear to play significant roles in memory. What’s more, evidence indicates that methods that target the components can enhance memory. Copyright © 2004 Society for Neuroscience

Keyword: Learning & Memory
Link ID: 5603 - Posted: 06.24.2010

Expressing high levels of a sugar-adding protein known as LARGE in mice that lack the protein can prevent muscular dystrophy in these animals, according to studies by researchers at the University of Iowa Roy J. and Lucille A. Carver College of Medicine. Furthermore, the research suggests that LARGE protein also can restore normal function to a critical muscle protein that is disrupted by glycosylation (sugar-adding) defects in several different human muscular dystrophies. The team's findings, which appear June 6 in an advanced online publication of Nature Medicine and online in the journal Cell on June 3, might lead to new treatments for this particular class of muscular dystrophies and other muscle diseases caused by glycosylation defects. A group of muscular dystrophies, which include Fukuyama Congenital Muscular Dystrophy, Walker-Warburg Syndrome and Muscle-Eye-Brain disease, are caused by mutations in glycosylation enzymes – proteins that add sugars to other proteins. In these diseases, defects in the sugar-adding mechanism disrupt the properties of alpha-dystroglycan, a protein critical for normal muscle function.

Keyword: Muscles; Movement Disorders
Link ID: 5602 - Posted: 06.24.2010

Local snoozing implies that slumber makes for better learning. TANGUY CHOUARD A good night's rest is hard work for parts of your brain, say US neuroscientists. Regions related to learning show increased activity in sleepers who spent their evening mastering a new skill, they say. The discovery shows that sleep is valuable for consolidating new information and is not a simple 'standby' mode. Local brain processing during the night led to new skills being more firmly cemented, the research indicates. Giulio Tononi of the University of Wisconsin-Madison and his colleagues measured electrical brain signals in subjects who learned a simple computer game before going to sleep. The kind of activity that occurs during sleep was increased in a penny-sized region in the brains of slumbering subjects who had learned the game. Just playing the game did not have this effect. The researchers conclude that sleep falls on brain circuits that have been changed, not just used, during the day. (C) Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Sleep; Learning & Memory
Link ID: 5601 - Posted: 06.08.2004

Scientists are working on a new decontamination method to kill the proteins that cause the human form of mad cow disease. They hope their work eradicates even the tiniest potential for patients to contract vCJD from surgical equipment. The technique, a form of electrolysis, has been successfully tested on some forms of protein. Its developers, from Exeter University, hope it will also prove an effective way to kill the superbug MRSA. Lead researcher Dr Claus Jacob told BBC News Online the technique took advantage of the fact that surgical instruments were made of metal, and so could conduct electricity. It works by connecting the instrument to a battery-type device, and feeding through a very low voltage electrical current. This produces a series of chemical reactions on the surface of the instrument, which generate highly reactive oxygen particles that destroy biological matter clinging to the surface of the instrument. In some respects, the technology mimics the way that the body's immune system generates similar oxygen particles to fight off bacterial infection. (C)BBC

Keyword: Prions
Link ID: 5600 - Posted: 06.06.2004

It may sound like a load of quackers but according to new research ducks have regional accents. "Cockney" ducks from London make a rougher sound, not unlike their human counterparts, so their fellow quackers can hear them above the city's hubbub. But their country cousins communicate with a softer, more relaxed sound, the team from Middlesex University found. Ducks, like humans, are influenced by their environment, said Dr Victoria De Rijke, who has been nicknamed Dr Quack. Her research team discovered the difference after recording the quacks of ducks at two separate locations. The birds at Spitalfields City Farm in the heart of the cockney east London, were found to be "much louder and vocally excitable" than the ducks recorded on Trerieve Farm in Downderry, Cornwall, said English language lecturer Dr De Rijke. "The Cornish ducks made longer and more relaxed sounds, much more chilled out. "The cockney (London) quack is like a shout and a laugh, whereas the Cornish ducks sound more like they are giggling," she added. "London ducks have the stress of city life and a lot of noise to compete with, like sirens, horns, planes and trains."

Keyword: Language; Evolution
Link ID: 5599 - Posted: 06.06.2004

By LESLIE BERGER TWO years after a bombshell dropped on hormone replacement therapy, there are signs that the rush away from the drugs is ending. In July 2002, a federal study, part of the Women's Health Initiative, was halted when its data showed the dangers of hormone therapy outweighing its long-term benefits. Sales of the drugs — estrogen and estrogen-progestin — plunged. But new figures show that in recent months the drop appears to be bottoming out. Some doctors report an upswing in demand from menopausal women unable to find other sources of relief. Drugmakers, who have introduced low-dose versions of the products, are making their first new marketing forays. And some prominent doctors are even beginning to argue that women have been needlessly scared away from treatment. Of course, the grand hope of the past is gone: that giving older women a substitute for the estrogen they produced in their youth could stave off heart disease, strokes and dementia. The new approach emphasizes the lowest dose for the shortest time — and only for relief of hot flashes and other menopausal symptoms. Copyright 2004 The New York Times Company

Keyword: Hormones & Behavior
Link ID: 5598 - Posted: 06.24.2010

Loss of cones in the retina may cause some types of colour blindness Scientists have found that some colour blind people are missing as many as one third of the normal number of specialised light-detecting cells. However, apart from colour blindness, the general quality of their sight appears unaffected. The researchers hope their work will enable earlier detection of eyesight disorders. The study, by the University of Rochester, is published in Proceedings of the National Academy of Sciences. The Rochester team used a technique called adaptive optics to study the retina of the eye in much closer detail than has previously been possible. It was originally developed to help astronomers see more clearly through the Earth's atmosphere. Lead researcher Dr Joseph Carroll said: "Not only are we excited to show how this method can reveal us living cells in a way never before possible, but it's revealed a mystery with profound implications. "If a third of the light-receiving cells in your eye are absent and you don't even notice it, it means that when a patient complains to a doctor about waning light sensitivity, then the damage must already be very serious." (C)BBC

Keyword: Vision
Link ID: 5597 - Posted: 06.05.2004