A tiny protein called ADDL could be the key to Alzheimer's By Tom Valeo Scientists have long suspected that the protein clumps and tangles identified by Alois Alzheimer in 1907 somehow cause the disease that bears his name, probably by killing neurons. Now some researchers are blaming a much smaller form of protein, one that apparently produces memory deficits merely by binding to neurons and disrupting their ability to transmit signals. The search has begun for an antibody that would destroy these tiny proteins--or ADDLs--thereby preventing the onset of Alzheimer's disease and possibly even reversing the early symptoms. The discovery of ADDLs explains glaring anomalies in the conventional thinking about Alzheimer's, which holds that fragments of amyloid precursor protein, produced by normal neurons, aggregate into sticky, insoluble plaques that damage neurons. The problem with this theory is that virtually every older person carries some amyloid plaque, but only a few develop Alzheimer's. Conversely, those with Alzheimer's often have relatively few plaques. Another proposed culprit is the presence of tangles of tau protein, which form inside neurons and coincide with the collapse of microtubules that support the cell body and transport nutrients. The tau tangles correlate much better with the disease but tend to appear later, suggesting that they are a consequence, not a cause. © 1996-2004 Scientific American, Inc.

Keyword: Alzheimers
Link ID: 5509 - Posted: 06.24.2010

PROVIDENCE, R.I. — Male bullfrogs communicate with other bullfrogs through calls made up of a series of croaks, some of which contain stutters, according to a new Brown University study which describes a pattern not previously identified in scientific literature. Researchers recorded 2,536 calls from 32 male bullfrogs in natural chorus and analyzed the number of croaks in each call and the number of stutters in each croak. It is known that the male bullfrog’s call attracts females for mating, maintains territorial boundaries with other males, and indicates that the frog is healthy and aggressive. “Some animals have evolved large, complex vocabularies to communicate, while others say a lot with very limited numbers of calls,” said Andrea Simmons, professor of psychology, who presented the findings at 75th meeting of the Acoustical Society of America Monday, May 24, 2004. “A fundamental question in the study of communication by sound is ‘how much information can a sender convey in a single sound’?”

Keyword: Animal Communication; Sexual Behavior
Link ID: 5508 - Posted: 06.24.2010

Amyloid fibers, those clumps of plaque-like proteins that clog up the brains of Alzheimer's patients, have perplexed scientists with their robust structures. In laboratory experiments, they are able to withstand extreme heat and cold and powerful detergents that cripple most other proteins. The fibers are in fact so tough that researchers now are exploring ways that they can be used in nanoscale industrial applications. While they are not necessarily the cause of Alzheimer's, they are associated with it and with many other neurological conditions, and researchers don't yet have a way to assail these resilient molecules. A study published this week in the advance online publication of the journal Science suggests that yeast may succeed where scientists have not. The research by a team at Whitehead Institute for Biomedical Research reports on a natural biological process by which yeast cells dismantle amyloid fibers. "These proteins are remarkably stable," says Susan Lindquist, director of Whitehead and lead researcher on the project. "This is the first time that anyone has found anything that can catalytically take apart an amyloid fiber."

Keyword: Alzheimers
Link ID: 5507 - Posted: 05.22.2004

John Travis As fans of the famous Westminster Dog Show will attest, dogs come in all shapes and sizes. The most thorough DNA analysis yet of purebred dogs suggests that canine breeds, typically defined by physical features and family history, can also be discerned genetically with great accuracy. "At a DNA level, breeds are a very real concept. Every poodle is more closely related to a poodle than it is to a dog of any other breed," says Elaine Ostrander of the Fred Hutchinson Cancer Research Center in Seattle. In the May 21 Science, she and her colleagues describe their analysis of DNA from 85 dog breeds. The new study is the latest spin—off from efforts to use man's best friend to investigate human health. Over the past few centuries, dog owners have created hundreds of breeds with strikingly different temperaments and physical characteristics. This inbreeding, however, has generated many breed-specific problems, such as deafness and osteoporosis, that also afflict people. Copyright ©2004 Science Service. All rights reserved.

Keyword: Genes & Behavior; Evolution
Link ID: 5506 - Posted: 06.24.2010

Almost 4000 Britons aged between 10 and 30 may be harbouring the prion proteins that cause the human form of mad cow disease. The new estimate comes from direct analyses of human biopsies, and is much higher than epidemiological projections of the likely number of deaths from variant Creutzfeldt-Jakob Disease (vCJD). The investigators discovered three infected tonsil or appendix samples from a total of 12,674 stored between 1995 and 1999. However, because so few positive samples were found, the projected total of 3808 can only be speculative. Furthermore, harbouring the prions may not necessarily lead to vCJD. "I don't think too much should be read into our findings, but they should be investigated further," says David Hilton, of the Derriford Hospital in Plymouth, UK, who led the study. He notes that only one of the three positive samples matched the usual pattern of prion accumulation seen in confirmed vCJD cases. © Copyright Reed Business Information Ltd.

Keyword: Prions
Link ID: 5505 - Posted: 06.24.2010

Music's ability to make us feel chirpy, sad, excited or just plain bored can be accurately predicted by only a few of its basic elements, an Australian scientist has discovered. "Among other things, loudness, tempo and pitch have a measurable impact on people's emotional response to music," says University of NSW music psychologist, Dr Emery Schubert. His is the first study of its kind to mathematically quantify the emotional impact of music. Sixty-seven subjects listened to four classical musical compositions while they moved a mouse over a computer screen to indicate the emotion they felt was being expressed musically. Their mouse movements indicated whether they found the music to be happy or sad and arousing or sleepy, on what Dr Schubert calls a "two-dimensional emotional space". These movements were automatically recorded by the computer once each second throughout the musical performance. "The results tell us that arousal is associated with a composition's loudness and to a lesser extent its tempo," says Dr Schubert, whose paper is to be published in the forthcoming issue of the journal, Music Perception. This was evident in the four compositions examined -- Slavonic Dance Opus No. 46 (Anton Dvorak), Concerto de Arunquez (Joaquin Rodrigo), Pizzicato Polka (Johan Strauss Jr and Josef Strauss) and 'Morning' (Edvard Grieg).

Keyword: Hearing; Emotions
Link ID: 5504 - Posted: 05.22.2004

Researchers continue to struggle to find a chemical cure for the seriously overweight By Stuart Blackman I'm a potential obese person," says Steve Bloom of Imperial College London. "I feel hungry all the time and have to keep [jogging] and restraining myself when they put chocolate biscuits on the table.... I keep my weight down, but I've still got a potbelly. And that's in spite of being an [obesity] expert and knowing what I'm supposed to do." Which, presumably, is to burn off and eliminate as many calories as one eats. It's an equation that is getting increasingly out of kilter, and a problem that science has been trying to tackle. A recent review describes the past 10 years as the "golden age" of obesity research.1 In that time, researchers have worked on a smorgasbord of molecules involved in body weight regulation via many overlapping systems and pathways. They have identified genes, including melanocortin 4 receptor and prohormone convertase 1, in which mutations lead to morbid obesity through their effects on appetite and metabolism. © 2004, The Scientist LLC, All rights reserved.

Keyword: Obesity
Link ID: 5503 - Posted: 06.24.2010

— Researchers have devised a genetic technique to distinguish the neurons in the spinal cord that control the sequential stepping of the left and right limbs. Their findings have literally taken them a step closer to understanding the neural circuitry that coordinates walking movements - which has been one of the main obstacles in developing new treatments for paralysis. According to the researchers, using genetic techniques to identify specific spinal neural networks could greatly enhance our knowledge of the intricate neural circuitry involved in spinal motor control. Moreover, a better understanding of this area is absolutely crucial in developing strategies to restore motor function caused by paralysis due to spinal injury or disease. The approach that the researchers used to identify these neurons will likely find broader application and be useful in defining the “local” circuitry that governs other rhythmic processes such as breathing, as well as reflex behaviors that do not involve the brain. ©2004 Howard Hughes Medical Institute

Keyword: Regeneration; Development of the Brain
Link ID: 5502 - Posted: 06.24.2010

— The first detailed genetic comparison of purebred domestic dogs promises to rewrite the textbooks with new information about breed classification and insights that may improve canine health by boosting understanding of the more than 350 inherited disorders, including cancer, heart disease, epilepsy, blindness and deafness, which affect dogs. In analyzing and carefully comparing the genetic information from dogs representing 85 breeds, the researchers were surprised to discover previously unappreciated relationships between existing breeds and new details that suggest completely unexpected breeds to be among the most ancient descendents of dogs' wolf-like ancestors. The researchers, led by Elaine A. Ostrander and Howard Hughes Medical Institute researcher Leonid Kruglyak, reported their findings in an article published in the May 21, 2004, issue of the journal Science. Kruglyak and Ostrander are at the Fred Hutchinson Cancer Research Center. Other co-authors are from the University of Washington and the University of Missouri. ©2004 Howard Hughes Medical Institute

Keyword: Genes & Behavior; Evolution
Link ID: 5501 - Posted: 06.24.2010

Scientists studying our brains may have found why mistakes can happen when we try to do too many things at one time. As this ScienCentral News video reports, they have found we need a little time to process everything we do. The next time you're driving, changing the radio station, talking on your cell phone, reading a road sign, and keeping an eye out for rogue bicyclists, you might want to try paying attention to one task at a time. "Attentional blink" is term psychologists use to describe our ability to be aware of an event or object, such as a sign on the road or someone's face, even if we are paying attention to another visual event. But what goes on in the brain during the attentional blink? Rene Marois, a psychologist at Vanderbilt University, wanted to find out. Marois and his team used functional magnetic resonance imaging (fMRI) to monitor the brains of 20 participants while they were presented with a barrage of visual information. The researchers mixed in an image of a face and an intact scene among a bunch of other scrambled indoor and outdoor scenes. The intact scene was shown about a half a second after the image of the face. © ScienCentral, 2000-2004.

Keyword: Attention; Brain imaging
Link ID: 5500 - Posted: 06.24.2010

Removal of an enzyme that regulates the activity of many proteins can suppress key features of Alzheimer's disease in experimental models, researchers at the Gladstone Institute of Neurological Disease (GIND) recently reported in the Journal of Neuroscience. Using well-established mouse models of Alzheimer's disease, the investigators examined how changing levels of the enzyme Fyn affects key aspects of the disease, including accumulation of large clumps of amyloid proteins in the brain (so-called plaques) and changes in the complex neuronal networks in which memories are formed and stored. Genetic engineering strategies were used to increase or decrease the expression of Fyn, which regulates many other proteins through the attachment of specific groups of atoms known as phosphate groups. The researchers determined that changing levels of Fyn had no effect on plaque formation or aberrant sprouting (the abnormal growth of nerve terminals, in which neuchemical messages are stored), indicating that these pathologies involve discrete molecular mechanisms. However, they observed that blocking Fyn expression prevented amyloid proteins from damaging synapses, the specialized connections between brain cells, and improved the longevity of mice. (Experimental mice with Alzheimer's-like disease otherwise die prematurely.) In contrast, increasing Fyn in the brain worsened synaptic damage, and also increased the number of premature deaths in the mice.

Keyword: Alzheimers
Link ID: 5499 - Posted: 05.20.2004

Chicago, Ill. -- Restless legs syndrome (RLS) may sound like something right out of a 1950s horror flick. And for some sufferers, it is. This affliction causes an irresistible urge to move the legs often accompanied by creepy-crawly sensations in the legs. The sensations are only relieved by movement, and become worse as the sun goes down. Night after night this sleeplessness occurs for the millions who suffer with RLS and their partners. Because little is known about what causes RLS, researchers at Penn State College of Medicine and Johns Hopkins University went looking for answers. The team, led by James Connor, Ph.D., professor and interim chair, Department of Neuroscience and Anatomy, Penn State College of Medicine, performed the first-ever autopsy analysis of the brains of people with RLS. This research, presented June 5 at the Association of Professional Sleep Societies meeting in Chicago, uncovered a possible explanation for this syndrome. "We found that, although there are no unique pathological changes in the brains of patients with RLS, it appears that cells in a portion of the mid-brain aren't getting enough iron," Connor said. "It was a relief to many that there was no neurodegeneration, or loss or damage of brain cells, like we see in Parkinson's and Alzheimer's disease."

Keyword: Sleep
Link ID: 5498 - Posted: 05.20.2004

BY JAMIE TALAN, STAFF WRITER Smokers who say lighting up helps them concentrate may actually be right, according to new findings on how nicotine affects the brain. While the work is based on research on animals, scientists at Columbia University College of Physicians and Surgeons say they suspect nicotine blocks some of the human brain's "background noise" so a person can pay attention to more important information. David Sulzer, associate professor of neurology and psychiatry and lead author of the study that appears in Nature Neuroscience, said this finding may explain why most people with schizophrenia smoke a lot. Nicotine may be filtering the stimuli that seems to flood the schizophrenic brain and leads to a jumble of thought and behavior. Smoking may help tune out some of this excess information, Sulzer said. Copyright © 2004, Newsday, Inc.

Keyword: Attention; Drug Abuse
Link ID: 5497 - Posted: 06.24.2010

Scientists have found a drug which appears to slow the progress of the debilitating condition Huntington's Disease, which currently has no cure. Animal tests by Cambridge University researchers showed that rapamycin also delays the onset of the disease. The drug is already used in humans to prevent organ rejection after transplants. Huntington's Disease groups hailed the research, published in Nature Genetics, as a significant advance. The disease, caused by a mutation in the huntingtin protein which makes it become toxic, is an inherited condition. It affects the central nervous system and can lead to loss of muscle control, dementia and depression. Huntington's normally affects people in middle age, but it can strike at any time. It is estimated that around 50,000 people in the UK either suffer from the disease or are at risk of developing it. (C)BBC

Keyword: Huntingtons
Link ID: 5496 - Posted: 05.19.2004

Even the least graceful among us has motor control the most high-tech unmanned undersea vehicle would envy, thanks to a region of the brain that allows our bodies to carry out complex maneuvers. The Office of Naval Research, which traditionally relies on the power of the human mind to achieve breakthroughs in science and technology, now also is harnessing the working principle of the brain to control the maneuvers of UUVs. This summer at the Naval Undersea Warfare Center in Newport, RI, a mobile autonomous research vehicle (MARV) fitted with an agile "brain-based" controller will attempt to smoothly and quietly maneuver itself in and out of a docking tube. This tricky feat could be critical to future missions in which UUVs might carry out missions too dangerous for humans. ONR project sponsor Tom McKenna says that the controller, developed jointly by Russia's Nizhny Novgorod State University and Institute for Applied Sciences and New York University Medical School, mimics the part of the human brain that controls balance and limb movement, known as the olivo-cerebellar system.

Keyword: Robotics
Link ID: 5495 - Posted: 05.19.2004

By SANDRA BLAKESLEE An examination of scientific studies worldwide has found no convincing evidence that vaccines cause autism, according to a committee of experts appointed by the Institute of Medicine. In particular, no link was found between autism and the measles-mumps-rubella vaccine or vaccines that contain a mercury preservative called thimerosal. The committee released its eighth and final report yesterday in Washington. Some parents of autistic children immediately protested. Mark Blaxill, the father of an 8-year-old girl with autism, said the committee's conclusions were premature. Studies are under way that should not be dismissed, said Mr. Blaxill, who is a director of the Coalition for SafeMinds, an advocacy group that finances research on the possible connection between autism and vaccines. Representative Dave Weldon, a physician and a Republican from Florida who is an advocate for the parents, said the report was "based on preliminary, incomplete information and may ultimately be repudiated." Copyright 2004 The New York Times Company

Keyword: Autism
Link ID: 5494 - Posted: 05.19.2004

By Charnicia E. Huggins NEW YORK (Reuters Health) - Various reports indicate that young people who use cannabis tend to experience psychological and social problems. However, there is no evidence that marijuana use is directly linked with such problems, according to the results of a study published in The Lancet. "Currently, there is no strong evidence that use of cannabis of itself causes psychological or social problems," such as mental illness or school failure, lead study author Dr. John Macleod of the University of Birmingham in the UK told Reuters Health. "There is a great deal of evidence that cannabis use is associated with these things, but this association could have several explanations," he said, citing factors such as adversity in early life, which may itself be associated with cannabis use and psychosocial problems.

Keyword: Drug Abuse
Link ID: 5493 - Posted: 05.19.2004

One of the nation's leading scientific institutions has come out with its most conclusive finding yet that there is no scientific evidence that childhood vaccines can cause autism. As this ScienCentral News video reports, the study comes after some parents failed to get their children immunized, sometimes with tragic results. When four-year-old Mary Catherine Walther was born, her mother Suzanne decided not to have her vaccinated. "I had been told that vaccines were dangerous," Walther explains. But when Mary Catherine was one year old, she got bacterial meningitis, a serious infection of the central nervous system that can cause brain damage, hearing loss, blindness, paralysis, coma and even death. It is prevented by the Haemophilus influenzae type B (Hib) vaccine. "When I found out, 'Oh, this is a germ, this is a germ that is a vaccine-preventable disease,' I was just stunned," says Walther. "I was really angry." Like Walther, many parents looking for information about vaccinations find media reports that treat claims of a link between vaccines and autism as fact. Now, after a four-year investigation, the Institute of Medicine (IOM) of the National Academy of Sciences has released its final report on vaccines and autism and found no connection. © ScienCentral, 2000-2004.

Keyword: Autism
Link ID: 5492 - Posted: 06.24.2010

By CAROL KAESUK YOON When it comes to choosing a mate, animals — be they butterflies, frogs, elephants or humans — have strong preferences. They gravitate to the one with the glittering scales, the warbling call, that ineffable something. Such predilections may seem harmless, except perhaps to those not preferred. But they can be major obstacles to scientists trying to breed rare species back into abundance with just a few potential mates. Although Noah may have had no problems working with a single pair of every animal, researchers often find that animals they try to mate will refuse to have anything to do with each other. What with famously recalcitrant lovers like giant pandas (not to mention cloud leopards, an endangered species whose males sometimes kill females presented to them), many animals simply cannot be enticed to love the one they're with. Now scientists working with a declining species, the harvest mouse, report that by using a few simple aromatic manipulations they have taken males that were once entirely unappealing to some females, and have made them altogether more alluring. The technique involves marking objects in the animals' cages with scents given off by the most appealing males. Copyright 2004 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 5491 - Posted: 06.24.2010

Following a low-carbohydrate, high-protein diet is a more effective way to lose weight than following a low fat diet, say US researchers. Two studies published in the journal Annals of Internal Medicine found weight loss was greatest when people followed an Atkins-style diet. Cholesterol levels also seemed to improve more on a low-carb diet compared to a low-fat diet. However, the research was funded by the Robert C Atkins Foundation. In the first study, researchers at Duke University Medical Center in Durham, North Carolina, assigned 120 obese volunteers to either a low-carbohydrate, high-protein diet or a low-fat, low-cholesterol, low-calorie diet. After six months, the people on the Atkins-style diet had lost an average of 26 pounds, compared to an average of 14 pounds in the conventional low-fat diet group. The low-carbohydrate, high-protein diet also had a good effect on fat levels. The Atkins dieters lost more body fat, lowered their triglyceride levels and raised their "good" HDL cholesterol levels more than the low-fat dieters. (C)BBC

Keyword: Obesity
Link ID: 5490 - Posted: 05.18.2004