People who spend more time in the sun as children subsequently have a lower risk of developing multiple sclerosis (MS), a US study shows. The University of Southern California team suggest UV rays offer protection by altering the cell immune responses or by boosting vitamin D levels. An earlier study found women who took vitamin D supplements were 40% less likely to develop MS. The latest research is published in the journal Neurology. MS is among the most common neurological diseases affecting around two million people worldwide. However, it is more common at higher latitudes, which generally have lower levels of ultraviolet radiation - the type produced by the sun. People in these countries are exposed to less sunlight, which triggers a chemical reaction in the body leading to vitamin D production. For the study, researchers surveyed 79 pairs of identical twins who had the same genetic risk of MS. In each pair, one of the twins had MS. The twins were asked to specify whether they or their twin spent more time outdoors during hot days, cold days, and summer, and which one spent more time basking in the sun, going to the beach and playing team sports as a child. The researchers found the twin with MS spent less time in the sun as a child than the twin who did not have MS. (C)BBC

Keyword: Multiple Sclerosis
Link ID: 10547 - Posted: 07.30.2007

By NICHOLAS WADE Medical researchers have made a significant advance in understanding multiple sclerosis, a common neurological disease that causes symptoms ranging from muscle weakness to paralysis. The disease is one in which the body’s immune system mistakenly attacks the electrical insulation of nerve fibers. The cause is part genetic and part environmental, but researchers trying to identify the relevant genes have endured repeated frustration. Their approach has been to guess what genes might be involved and see if patients have abnormal versions. This guesswork has produced more than 100 candidate genes in recent years, none of which could be confirmed except for long-known variants in the mechanism used by the immune system to recognize proteins that are foreign to the body. In three articles published online yesterday in The New England Journal of Medicine, three teams of researchers say they have identified, by separate routes, new genetic variants that contribute to the disease. One team used a new, advanced gene-hunting method called Whole Genome Association, which has racked up a string of successes with major diseases in the last few months. The other teams used the candidate gene approach, but because all three teams identified the same gene, the researchers say they are confident they have opened a new window into the cause and possible treatment of multiple sclerosis. Copyright 2007 The New York Times Company

Keyword: Multiple Sclerosis
Link ID: 10546 - Posted: 06.24.2010

SEATTLE: – One of the greatest medical mysteries of our time has taken a leap forward in medical understanding with new study results announced by Dr. Daniel D. Rubens of Children’s Hospital and Regional Medical Center in Seattle. Rubens’ study published in July, 2007 in Early Human Development found all babies in a Rhode Island study group who died of Sudden Infant Death Syndrome (SIDS) universally shared the same distinctive difference in their newborn hearing test results for the right inner ear, when compared to infants who did not have SIDS. This is the first time doctors might be able to identify newborns at risk for SIDS by a simple, affordable and routine hearing test administered shortly after birth. In the study, medical records and hearing tests of 31 babies who died from SIDS in Rhode Island were examined and compared to healthy babies. Rhode Island has a particularly robust database of newborn hearing test data. The cause of SIDS, known around the world as “crib death” and “cot death,” has eluded physicians and grieving parents for centuries. Responsible for many previously unexplainable deaths of infants usually two to four months old and striking boys more than girls, SIDS causes tragic, sudden death in approximately 1 in 1,000 newborns world-wide, making it the largest cause of death in young infants. In the United States approximately 3,600 deaths each year were attributed to SIDS from 1992-1999, according to an April, 2004 article in Archives of Pediatric and Adolescent Medicine. Death occurs during sleep, seemingly with no warning and no previous symptoms. Changes in infant care have been promoted including the “Back to Sleep” program discouraging sleeping on the stomach, and avoiding exposure to cigarette smoke. Various causes have been suggested, including disturbances in respiratory control and infant overheating, but to date nothing has proven conclusive.

Keyword: Hearing; Sleep
Link ID: 10545 - Posted: 06.24.2010

Heidi Ledford People with one of two common gene variants may be at increased risk of developing the autoimmune disorder multiple sclerosis (MS), researchers say. Both variants encode components of the immune system that are involved in preventing the body from attacking its own cells. Two papers1,2 published today in Nature Genetics independently pinpoint one of the variants, in the 'interleukin-7 receptor alpha chain' (IL7R) gene. A third research team scanned the full genome for variants associated with MS, and found both IL7R and another interleukin receptor gene — 'interleukin-2 receptor alpha' (IL2R) — among the top hits3. In MS the body's immune system attacks the insulating sheath that surrounds and protects neurons, leading loss of motor function and cognitive decline. Interleukin-2 and interleukin-7 are immune system proteins that play a role in the function of regulatory T-cells, which help suppress autoimmunity. The three research teams analyzed thousands of patients of European descent, and found that a single base pair difference in the IL7R gene increased the risk of having MS by about 20%. That risk is too low to make IL7R useful for a genetic test, cautions Margaret Pericak-Vance, a geneticist at the University of Miami in Florida, and an author on one of the studies. "A lot of people carry this particular variant, and they don't get multiple sclerosis," she says. Roughly 70% of the European population is likely to have the variant. ©2007 Nature Publishing Group

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 10544 - Posted: 06.24.2010

Paul Marks Your ability to recall emotional events – such as meeting the love of your life, or the trauma of a painful car crash – is governed by a common variation in a single gene, according to a new study. We recall emotionally charged events far more than mundane ones because they tend to be advantageous in evolutionary terms. Remembering favourable or dangerous events helps our survival far more than recalling the daily commute to work, for example. Highly emotive incidents trigger the brain to release the hormone and neurotransmitter noradrenaline. This stimulates the amygdala – part of the brain involved with processing emotional reactions – to store memories in the hippocampus and other parts of the brain, says Dominique de Quervain, a neuroscientist at the University of Zurich in Switzerland. Yet for some reason, recall of emotional events varies a great deal from person to person. So de Quervain wondered if common variations in a gene called ADRA2B, which codes for the noradrenaline receptor, could be responsible. Some 30 per cent of Caucasians and 12 per cent of Africans possess this variant, he says. To find out, he and colleagues in Germany and Uganda showed photos of strongly positive, neutral and strongly negative emotional events to two large groups of people. They later asked the group members to recall them and describe them in writing. © Copyright Reed Business Information Ltd.

Keyword: Emotions; Genes & Behavior
Link ID: 10543 - Posted: 06.24.2010

By Charles Q. Choi A male crayfish with larger-than-normal claws typically needs only to flash his menacing weapons to drive opponents away. Now researchers find these critters are frequently bluffing — the enlarged claws often aren't stronger at all. These findings raise the question of how often males in the animal kingdom are just bluffing with their natural weaponry. "Dishonesty during disputes may be far more prevalent that we previously imagined," said researcher Robbie Wilson, a zoologist at the University of Queensland in Australia. Wilson and an international team of researchers investigated the Australian slender crayfish (Cherax dispar). The small, lobster-like crustaceans are extraordinarily aggressive beasts, with combat often resulting in death or the loss of a limb. "When you pick them up, they'll want to take your finger off right away," Wilson said. These two- to three-inch long creatures were collected from the creeks on the sand islands off southeast Queensland. Crayfish are freshwater creatures, while lobsters are marine animals. The bluffing finding emerged when the scientists randomly pit 32 adult male crayfish against each other, two at a time, in plastic aquariums. © 2007 MSNBC.com © 2007 Microsoft

Keyword: Aggression
Link ID: 10542 - Posted: 06.24.2010

By Michael Balter Humans are highly social, but we don't get pally with just anybody. Before forming relationships with other people, we normally size them up to see how trustworthy they are. A new study suggests that this behavior stems from an evolutionary reorganization in a part of the brain responsible for detecting other people's emotions. The amygdala, a small, almond-shaped area deep within our brains, appears to be essential in helping us read the emotions of others. Research shows that the structure is crucial for detecting fear, but scientists have also found evidence that it can help spot a wide variety of mental states (ScienceNOW, 7 April 2006). Last year, for example, scientists noted that the amygdalas of patients with autism, which is characterized by decreased social interaction and an inability to understanding the feelings of others, have fewer nerve cells, especially in a subdivision called the lateral nucleus. To see how the amygdala varies in different primate species, a team led by anthropologist Katerina Semendeferi of the University of California, San Diego, measured brain area in autopsy material from 12 ape and human specimens. The researchers found that although the human amygdala was much larger than those of the apes, it was actually the smallest when compared to overall brain size. © 2007 American Association for the Advancement of Science.

Keyword: Emotions
Link ID: 10541 - Posted: 06.24.2010

Cochlear implants bring hearing to thousands of otherwise deaf people. However, they have their limitations. John Middlebrooks of the University of Michigan's Kresge Hearing Research Institute explains how a new implant could improve pitch perception. Below is a transcript of the interview: This is an image of the cochlea of the human inner ear. The cochlea is a sort of a spiral snail shell. It has two and a half turns in the human. So here’s one, two, and a half turns. Now we see here a conventional cochlear implant. And notice that the cochlear implant only goes about one of the turns of the cochlea, so it doesn’t reach the apical turns of the cochlea that are sensitive to the lowest frequencies. Also notice that the cochlear implant resides within a bony chamber here called the scala tympani, so the signal from the cochlear implant has to go across this wall of bone to reach the auditory nerve fibers. The nerve implant that we’re testing now actually is inserted into the auditory nerve fibers so that the electrodes of the nerve implant lie in intimate contact with those auditory nerve fibers. Who are cochlear implants for? How do they work? Cochlear implants are used for people who are profoundly or severely deaf, so these are people that have often essentially no hearing through a conventional hearing aid. And these people have lost the hair cells that transduce sound into neural activity. So we can replace the function of those hair cells with a microphone and … electrodes. © ScienCentral, 2000-2007.

Keyword: Hearing; Robotics
Link ID: 10540 - Posted: 06.24.2010

Bruce Bower Although a variety of personal traits influence weight gain, obesity is socially contagious, moving from person to person through networks of friends and relatives, a new investigation finds. The study, the first to examine how social ties influence the development of obesity over time, finds that if one person becomes obese, others who know that person well have an increased risk of also becoming obese within the next 4 years. This effect occurs especially strongly among people identifying each other as friends. The proliferation of permissive attitudes about weight gain and large body sizes among social groups has contributed to soaring U.S. obesity rates, propose medical sociologist Nicholas A. Christakis of Harvard Medical School in Boston and political scientist James H. Fowler of the University of California, San Diego. "Obesity is not just an individual problem, it's a collective problem," Christakis says. The new findings appear in the July 26 New England Journal of Medicine. Christakis and Fowler tapped into previously unexamined data on 12,067 adults who underwent health assessments every 2 to 4 years, from 1971 to 2003, as part of the Framingham Heart Study. The researchers traced social networks for study participants by consulting records of contact information for each volunteer's close friends and relatives, many of whom also participated in the Framingham study and whose weights could also be tracked. ©2007 Science Service.

Keyword: Obesity
Link ID: 10539 - Posted: 06.24.2010

By Tuan C. Nguyen Until recently, wildlife biologists considered foxes, wolves and coyotes to be monogamous, a strategy that was presumed to give offspring a better chance of surviving, since monogamy often means that females have the helping hand of a male in raising newborns to adulthood. But a new study of Arctic foxes, detailed in the Canadian Journal of Zoology, finds that some do sleep around. Using a technique called microsatellite DNA fingerprinting, researchers at the University of Alberta in Edmonton and the University of Quebec at Rimouski looked at genetic samples from 49 Arctic foxes trapped in dens on Bylot Island, Nunavut. In three-quarters of the dens, fox cubs were the offspring of a single male and female. But in a quarter of the cases, the Arctic foxes proved to be less exclusive, with one litter providing the first genetic evidence of polyandry. "The generalization that mating couples stuck together usually came from field observations," said researcher Lindsey Carmichael of the University of Alberta in Edmonton. "People would often see pairs of foxes together and so they would just assume that was their standard mating pattern." There are various reasons for polyandry. © 2007 MSNBC.com © 2007 Microsoft

Keyword: Sexual Behavior
Link ID: 10538 - Posted: 06.24.2010

Louis Buckley Gender-bending chemicals could provide a new way to combat invasive species, say researchers. Originally conceived as a cure for the enormous populations of Asian carp and tilapia plaguing the Mississippi River, scientists now think the approach could be used to battle unwelcome crustaceans, molluscs, fish, amphibians and reptiles around the world. Invasions of exotic species are thought to be second only to habitat destruction as a threat to global biodiversity. The traditional approach to dealing with these interlopers has been to introduce a known predator and let nature take its course. But this has led to numerous disasters — for example, cane toads swamped Australia after being introduced to control the cane beetles blighting the country's sugar crop. In Florida, tilapia were deliberately introduced to control an aquatic weed, Hydrilla, that has been choking US rivers since the 1960s. Two species of snail were also introduced at a later date by the authorities, says Gutierrez, but neither they nor the tilapia chose to feed on Hydrilla, both preferring native species to the invader. In 2004, alerted to Florida's problems with invasive species, Juan Gutierrez, a bio-mathematician at Florida State University, constructed a mathematical model of a population in which males carry two different sex chromosomes (XY) and females are XX. In many species of fish, amphibians, and other animals, gender is determined not only by sex chromosomes, as it is in humans, but also by environmental conditions such as the presence of hormones, explains Gutierrez. ©2007 Nature Publishing Group

Keyword: Sexual Behavior; Evolution
Link ID: 10537 - Posted: 06.24.2010

Cochlear implants have been around for years, restoring hearing for many people. But, as this ScienCentral video explains, a new version is improving the quality of what patients hear. Dr. David Acus of Herrick Memorial Hospital in Tecumseh, Michigan was a twenty-five year veteran of the emergency room when hearing loss forced him to quit his job. Then he got a cochlear implant. “The cochlear implant is wonderful. It’s allowed me to go back to work.” In a healthy ear, vibrations are translated into electrical signals inside the cochlea, a small bony structure of the inner ear. The signals are sent to the brain via the auditory nerve. Congenital problems, injury, illness, or aging can cause hearing loss. One solution is to insert an electrical array into the cochlea that translates external sounds into electrical impulses. These conventional cochlear implants are remarkably effective, and have improved the hearing of nearly 100,000 deaf people worldwide. However, the implants stimulate the ear's auditory nerve indirectly, through the bony wall of the cochlea. Neuroscientist John Middlebrooks of the University of Michigan points out that muddles music and vocal tones. “It’s a little bit like playing a piano with boxing gloves on your hands: you can make a big sound, and you can touch all the keys, but you can’t play single keys individually.” © ScienCentral, 2000-2007.

Keyword: Hearing; Robotics
Link ID: 10536 - Posted: 06.24.2010

Daniel Cressey Frequent cannabis use more than doubles the risk of developing psychotic illnesses such as schizophrenia, according to the most rigorous analysis of the evidence to date. The finding, which comes from a new study that combines results from 35 previous surveys, represents a significant U-turn from previous suggestions that cannabis is harmless to mental health. The analysis is published in medical journal The Lancet, which in 1995 began one of its issues with the sentence: "The smoking of cannabis, even long term, is not harmful to health."1 In fact, having used the drug even once increases your risk of developing psychotic problems by 41%, according to the new research2. This suggests that 14% of all psychotic illness in Britain is caused by cannabis use. "The message that has to be made clear is there are potentially quite serious risks from using cannabis," says study author Stanley Zammit of Cardiff University, UK. "For psychotic outcomes there certainly is enough evidence to warn people of the risk." Zammit adds that the new analysis is the "most thorough" to date. "This adds a certain robustness to the evidence," he says. There is now sufficient evidence to warn young people that using cannabis could increase their risk of developing a psychotic illness later in life' ©2007 Nature Publishing Group

Keyword: Drug Abuse; Schizophrenia
Link ID: 10535 - Posted: 06.24.2010

Scientists believe they have identified the gene for itchiness, raising the hope of treatment for the condition. The GRPR "itch gene" was found in spinal cord nerve cells by a Washington University team. The researchers, who carried out tests on mice, say it is responsible for relaying itch signals from the skin to the brain, via the spinal cord. They say if they are right, it may hold the key for helping people with severe itching, the Nature journal reported. Chronic itching can be caused by skin disorders like eczema or can stem from deeper problems such as kidney failure or liver disease. It can also be a serious side-effect of cancer therapies or powerful painkillers like morphine. In the most serious cases it can lead to sleep problems and scarring, and yet researchers say there is little treatment available for it. Historically, scientists have regarded itching as a less intense version of pain and have tailored their research to understanding pain. In fact, it was during such research that the GRPR (gastrin-releasing peptide receptor) gene first came to the scientists' attention. The gene stood out as they noticed it was only present in a few spinal cord cells, but after carrying out tests on mice they realised it was not related to the pain pathway. However, they did find it had an impact when itching tests were carried out. Mice who had the gene neutralised did not react as much as those with the gene when given itchy stimuli. (C)BBC

Keyword: Pain & Touch
Link ID: 10534 - Posted: 07.27.2007

Obesity Spreads In Social Circles As Trends Do, Study Indicates By Rob Stein Obesity appears to spread from one person to another like a virus or a fad, researchers reported yesterday in a first-of-its-kind study that helps explain -- and could help fight -- one of the nation's biggest public health problems. The study, involving more than 12,000 people tracked over 32 years, found that social networks play a surprisingly powerful role in determining an individual's chances of gaining weight, transmitting an increased risk of becoming obese from wives to husbands, from brothers to brothers and from friends to friends. The researchers found that when one spouse became obese, the other was 37 percent more likely to do so in the next two to four years, compared with other couples. If a man became obese, his brother's risk rose by 40 percent. The risk climbed even more sharply among friends -- between 57 and 171 percent, depending on whether they considered each other mutual friends. Moreover, friends affected friends' risk even when they lived far apart, and the influence cascaded through three degrees of separation before petering out, the researchers found. "It's almost a cliche to speak of the obesity epidemic as being an epidemic. But we wanted to see if it really did spread from person to person like a fashion or a germ," said Nicholas A. Christakis of Harvard Medical School, who led the study, being published tomorrow in the New England Journal of Medicine. "And the answer is, 'Yes, it does.' We are finding evidence for a kind of social contagion." © 2007 The Washington Post Company

Keyword: Obesity
Link ID: 10533 - Posted: 06.24.2010

Many people believe potentially harmful myths about epilepsy, a study from University College London suggests. A third would put something in the mouth of a person having a seizure to stop them swallowing their tongue - but doing so could block their airways. And 67% of the 4,605 people asked would call an ambulance immediately, Epilepsy and Behavior journal reports. This is only needed for first seizures, those lasting over five minutes, if the person is hurt or has several seizures. The authors questioned 4,605 staff and students from the university on what happens when someone has a seizure and how they should be helped. Seizures are caused by sudden bursts of electrical activity in the brain, which stops the brain communicating normally with the body, and epilepsy is diagnosed in people who have regularly recurring seizures. Symptoms depend on the type of seizure, and experts recommend that if someone has a seizure, objects around them are removed and their head is cushioned if they are on the floor. Apart from that the seizure should be allowed to run its course. The authors focused on four key myths surrounding seizures: the need to call an ambulance, the need to put something in their mouth so they do not swallow their tongue, and the incidence of foaming at the mouth and violence in seizures. In fact, foaming and violence are not common symptoms of seizures but many people still believed these myths. (C)BBC

Keyword: Epilepsy
Link ID: 10532 - Posted: 07.25.2007

Randy Harris THE first farm animal Gene Baur ever snatched from a stockyard was a lamb he named Hilda. That was 1986. She’s now buried under a little tombstone near the center of Farm Sanctuary, 180 acres of vegan nirvana here in the Finger Lakes region of upstate New York. Back then, Mr. Baur was living in a school bus near a tofu factory in Pennsylvania and selling vegetarian hot dogs at Grateful Dead concerts to support his animal rescue operation. Now, more than a thousand animals once destined for the slaughterhouse live here and on another Farm Sanctuary property in California. Farm Sanctuary has a $5.7 million budget, fed in part by a donor club named after his beloved Hilda. Supporters can sign up for a Farm Sanctuary MasterCard. A $200-a-seat gala dinner in Los Angeles this fall will feature seitan Wellington and stars like Emily Deschanel and Forest Whitaker. As Farm Sanctuary has grown, so too has its influence. Soon, due in part to the organization’s work, veal calves and pregnant pigs in Arizona won’t be kept in cages so tight they can’t turn around. Eggs from cage-free hens have become so popular that there is a national shortage. A law in Chicago bans the sale of foie gras. Copyright 2007 The New York Times Company

Keyword: Animal Rights
Link ID: 10531 - Posted: 06.24.2010

By Nikhil Swaminathan In work that may one day lead to earlier detection of children at risk of developing autism, a team of scientists has devised a genetic model for the enigmatic disorder. The two-tiered theory integrates families with one or more autistic children. An estimated one in every 150 children born in the U.S. develops autism, according to the Centers for Disease Control and Prevention (CDC); it is four times more prevalent in boys than in girls. The condition is characterized by cognitive deficiencies and symptoms ranging from antisocial (not responding to one's name and / or avoiding eye contact) to obsessive, repetitive behavior. The most popular theory about its genesis is that there are flaws in several genes passed down through generations of a family that culminate to predispose a child to the disorder, especially if exposed to certain environmental factors such as toxic chemicals or a lack of oxygen at birth. "People thought there was this uniform risk—if you have an autistic child, then there's some uniform, but fairly low, risk that you'll have another one," says Michael Wigler, a professor of genomics at Cold Spring Harbor Laboratory (CSHL) in Long Island, N.Y., and senior author of the new model described in Proceedings of the National Academy of Sciences USA. "None of the population geneticists, in my experience, had thought that there might be two classes of families: low risk and high risk." The team determined that most cases of autism arise from novel, spontaneous mutations passed down from one or both parents, resulting in large gaps in a person's genome often encompassing several genes, which are then disrupted or inactivated. In most instances, this mutation will result in an autistic child. However, in some cases—more likely in girls than boys—the recipient of this mutation will not produce any symptoms. © 1996-2007 Scientific American, Inc

Keyword: Autism
Link ID: 10530 - Posted: 06.24.2010

A new study has revealed more about how the medication ketamine, when used experimentally for depression, relieves symptoms of the disorder in hours instead of the weeks or months it takes for current antidepressants to work. While ketamine itself probably won’t come into use as an antidepressant because of its side effects, the new finding moves scientists considerably closer to understanding how to develop faster-acting antidepressant medications — among the priorities of the National Institute of Mental Health (NIMH), part of the National Institutes of Health. Ketamine blocks a receptor called NMDA on brain cells, an earlier NIMH study in humans had shown, but the new study in mice shows that this is an intermediate step. It turns out that blocking NMDA increases the activity of another receptor, AMPA, and that this boost in AMPA is crucial for ketamine’s rapid antidepressant actions. The study was reported online in Biological Psychiatry on July 23, by NIMH researchers Husseini K. Manji, MD, Guang Chen, MD, PhD, Carlos Zarate, MD, and colleagues. “Our research is showing us how to develop medications that get at the biological roots of depression. This new finding is a major step toward learning how to improve treatment for the millions of Americans with this debilitating disorder; toward eliminating the weeks of suffering and uncertainty they have to endure while they wait for their medications to work,” said NIH Director Elias Zerhouni, M.D. Almost 15 million American adults have a depressive disorder. During the long wait to begin feeling the effects of conventional medications, patients may worsen, raising the risk of suicide for some.

Keyword: Depression
Link ID: 10529 - Posted: 06.24.2010

By Shirley Wang Anthony Mauger woke up at 5 a.m. one morning nearly 10 years ago and heard a message in his head telling him to kill himself. He wrote a goodbye note to his wife, then jumped off the back deck of their Kensington home, falling the 14 feet hard enough to wake her with the sound of his thud. The 66-year-old organic chemist succeeded only in smashing his knees and skull. After surgery at Suburban Hospital, he was transferred to Potomac Valley Nursing and Wellness Center in Rockville for intensive psychiatric care. Mauger had been depressed for about six months, his wife, Inge, remembers. His sleep had been poor, and he was making strange claims that he could not go on vacation or walk. The slew of antidepressants Mauger tried made no difference. After four more months watching her husband deteriorate, Inge Mauger was desperate. "Nothing is happening," she said to his psychiatrist. "Isn't there anything you can do?" "We can try ECT," he replied. Better known as shock therapy and seared into our collective consciousness as the involuntary procedure depicted in "One Flew Over the Cuckoo's Nest," electroconvulsive therapy remains a controversial treatment, often used, as in Mauger's case, only after other treatments fail. Its popularity has waxed and waned in its 70-year history, but an estimated 100,000 Americans undergo ECT each year, according to a 1995 survey of more than 17,000 psychiatrists, and its use appears to be steady or increasing since then. © 2007 The Washington Post Company

Keyword: Depression
Link ID: 10528 - Posted: 06.24.2010