By Tina Hesman Saey Two male squirrel monkeys now see the world in a whole new way — in full color. Female squirrel monkeys can see in color, but male squirrel monkeys are normally red-green colorblind because they lack pigments in the retina that detect those wavelengths of light. Now, researchers have performed gene therapy that allowed two male squirrel monkeys named Sam and Dalton to produce proteins that detect red light. As soon as the red-light-harvesting protein was made in the monkeys’ eyes, the animals were able to discriminate between red and green spots in color vision tests, Jay Neitz of the University of Washington in Seattle and his collaborators report online September 17 in Nature. The experiment wasn’t supposed to work, Neitz says. People born with cataracts don’t develop nerve connections that help the brain make sense of messages sent by the eye. If the defect isn’t corrected early, these people remain essentially blind even if their eyes return to full function later. Because there was no reason to assume color vision was different from other types of vision, the team had assumed it would not be possible to reverse the deficit in an adult animal. Neitz polled experts in the vision field on whether they thought producing photoreceptors in colorblind adult monkeys could give color vision. “Every single person said, ‘absolutely not.’” But the researchers decided to move forward with the experiment to see if they could get the pigment protein to be made in the eye. © Society for Science & the Public 2000 - 2009

Keyword: Vision; Genes & Behavior
Link ID: 13281 - Posted: 06.24.2010

Young children's exposure to lead in the environment is harming their intellectual and emotional development, according to UK researchers. The researchers say the toxic effects of lead on the central nervous system are obvious even below the current so-called safe level of lead in the blood. They are recommending the threshold should be halved. A spokesman for the Health Protection Agency said levels of exposure should be kept to the minimum. Lead has been removed from paint and petrol by law in the UK, but it is still widespread in the environment. The study from the University of Bristol Centre for Child and Adolescent Health set out to see if there was any effect on the behaviour and intellectual development of children who had ingested just below the so-called safe level of 10 microgrammes per decilitre (or tenth of a litre) of blood. The study is published in the journal, Archives of Diseases in Childhood. The Bristol researchers took blood samples from 582 children at the age of 30 months. They found 27% of the children had lead levels above five microgrammes per decilitre. They followed the children's progress at regular intervals and then assessed their academic performance and behavioural patterns when they were seven to eight years old. After taking account of factors likely to influence the results, they found that blood lead levels at 30 months showed significant associations with educational achievement, antisocial behaviour and hyperactivity scores five years later. With lead levels up to five microgrammes per decilitre, there was no obvious effect. But lead levels between five and 10 microgrammes per decilitre were associated with significantly poorer scores for reading ( 49% lower) and writing (51% lower). A doubling in lead blood levels to 10 microgrammes per decilitre was associated with a drop of a third of a grade in their Scholastic Assessment Tests (SATs). And above 10 microgrammes per decilitre children were almost three times as likely to display antisocial behaviour patterns and be hyperactive than the children with the lower levels of lead in their blood. (C)BBC

Keyword: Development of the Brain; Neurotoxins
Link ID: 13280 - Posted: 09.17.2009

by Nora Schultz, Berlin NEUROSCIENCE could do for schools what biomedical research has done for healthcare. That's the conclusion of the Decade of the Mind (DOM) symposium last week in Berlin, Germany, to discuss how the latest findings could be used to improve education. "In medicine, we have an excellent system in place to go from basic research to clinical practice, while in neuroscience we have the basic understanding of how the brain learns but still need to figure out how to translate this into the classroom," says Manfred Spitzer of the University of Ulm in Germany, one of the conference organisers. With brain imaging and, increasingly, genetic studies now complementing psychology research, a host of new findings could inform teachers about the conditions in which our brains can be primed to learn best. One of the main themes emerging at the DOM meeting was that the foundation of successful learning is improving executive function - a collection of cognitive processes important for self-control and focusing on the task at hand. Brain-imaging studies have mapped executive function to several regions, including the anterior cingulate gyrus, which also lights up during error detection and when children learn numeracy and literacy. Various studies presented at the meeting showed that improving a child's executive function could be achieved with relatively small changes, for example, by altering the timetabling of exercise sessions or encouraging the learning of a musical instrument (see "Stretch and learn" and "The Stephen King effect") Improving a child's ability to focus on the task at hand can be achieved with relatively small changes © Copyright Reed Business Information Ltd

Keyword: Learning & Memory; Development of the Brain
Link ID: 13279 - Posted: 06.24.2010

By Jesse Bering It’s my impression that many straight people believe that there are two types of gay men in this world: those who like to give, and those who like to receive. No, I’m not referring to the relative generosity or gift-giving habits of homosexuals. Not exactly, anyway. Rather, the distinction concerns gay men’s sexual role preferences when it comes to the act of anal intercourse. But like most aspects of human sexuality , it’s not quite that simple. I’m very much aware that some readers may think that this type of article does not belong on this website. But the great thing about good science is that it’s amoral, objective and doesn’t cater to the court of public opinion. Data don’t cringe; people do. Whether we’re talking about a penis in a vagina or one in an anus, it’s human behavior all the same. The ubiquity of homosexual behavior alone makes it fascinating. What’s more, the study of self-labels in gay men has considerable applied value, such as its possible predictive capacity in tracking risky sexual behaviors and safe sex practices. People who derive more pleasure (or perhaps suffer less anxiety or discomfort) from acting as the insertive partner are referred to colloquially as “tops,” whereas those who have a clear preference for serving as the receptive partner are commonly known as “bottoms.” There are plenty of other descriptive slang terms for this gay male dichotomy as well, some repeatable (“pitchers vs. catchers,” “active vs. passive,” “dominant vs. submissive”) and others not—well, not for Scientific American , anyway. © 1996-2009 Scientific American Inc.

Keyword: Sexual Behavior
Link ID: 13278 - Posted: 06.24.2010

By C. CLAIBORNE RAY Q. Is addiction to nicotine stronger than addiction to cocaine? A. The two addictions are believed to involve similar brain pathways, and craving for both drugs has been found in one study to be reduced by mecamylamine, a drug used to block the rewarding effects of nicotine. But a 2006 study in the journal Addiction by Jack E. Henningfield, a researcher for the National Institute on Drug Abuse, examined the strength of the addictions on several measures and concluded that nicotine addiction could not be considered stronger than cocaine addiction. All drugs of abuse stimulate the release of the neurotransmitter dopamine. This is believed to be involved in producing feelings of pleasure and reward, and eventually in cravings for the drug when it is withdrawn. Nicotine, like cocaine, activates nerve cells in the brain’s mesolimbic system that contain dopamine. In the study comparing addictions to the two, the researchers considered several lines of evidence — including patterns of use, mortality and potential for physical dependence — and found that while both are highly addicting drugs, current evidence does not show nicotine to be more addicting than cocaine. For both, the study said, patterns of use and dependence are strongly influenced by factors like availability, price, regulations and social pressures, as well as pharmacological characteristics. Copyright 2009 The New York Times Company

Keyword: Drug Abuse
Link ID: 13277 - Posted: 06.24.2010

By Bruce Bower Some mental disorders aren’t merely common—they’re the norm. Depression, anxiety disorders, alcohol dependence and marijuana dependence affect roughly twice as many people as had previously been estimated, a new study finds. Nearly 60 percent of the population experiences at least one of these mental disorders by age 32, say study directors and psychologists Terrie Moffitt and Avshalom Caspi, both of Duke University in Durham, N.C. That figure probably gets higher by the time people reach middle age, Moffitt suggests, as additional people develop at least one of these four ailments for the first time. In a paper published online September 1 and in an upcoming Psychological Medicine, Moffitt and Caspi present results from a study of more than 1,000 New Zealanders assessed for mental disorders 11 times between ages 3 and 32. This study took a prospective approach, following people as they aged, and assessed prevalence rates based on long-term data. Moffitt’s team focused most intensely on the period from age 18 to 32, when these disorders first start to appear. Earlier prevalence estimates for mental disorders in the United States and New Zealand relied on self-reports and therefore adults’ ability to remember and willingness to recount their own past emotional problems. “Like flu, if you follow a cohort of people born in the same year, as they age almost all of them will sooner or later have a serious bout of depression, anxiety or a substance abuse problem,” Moffitt says. © Society for Science & the Public 2000 - 2009

Keyword: Depression; Drug Abuse
Link ID: 13276 - Posted: 06.24.2010

By NICHOLAS WADE The first words ever spoken, so fable holds, were a palindrome and an introduction: “Madam, I’m Adam.” A few years ago palindromes — phrases that read the same backward as forward — turned out to be an essential protective feature of Adam’s Y, the male-determining chromosome that all living men have inherited from a single individual who lived some 60,000 years ago. Each man carries a Y from his father and an X chromosome from his mother. Women have two X chromosomes, one from each parent. The new twist in the story is the discovery that the palindrome system has a simple weakness, one that explains a wide range of sex anomalies from feminization to sex reversal similar to Turner’s syndrome, the condition of women who carry only one X chromosome. The palindromes were discovered in 2003 when the Y chromosome’s sequence of bases, represented by the familiar letters G, C, T and A, was first worked out by David C. Page of the Whitehead Institute in Cambridge, Mass., and colleagues at the DNA sequencing center at Washington University School of Medicine in St. Louis. They came as a total surprise but one that immediately explained a serious evolutionary puzzle, that of how the genes on the Y chromosome are protected from crippling mutations. Unlike the other chromosomes, which can repair one another because they come in pairs, one from each parent, the Y has no evident backup system. Nature has prevented it from recombining with its partner, the X, except at its very tips, lest its male-determining gene should sneak into the X and cause genetic chaos. Copyright 2009 The New York Times Company

Keyword: Sexual Behavior
Link ID: 13275 - Posted: 06.24.2010

By Jeanna Bryner Some animals are more thoughtful than others, according to a comparative psychologist who says evidence is mounting that dolphins, macaque monkeys and other animals share our ability to reflect upon, monitor or regulate their states of mind. J. David Smith of the University at Buffalo notes that humans are capable of metacognition, or thinking about thinking. "Humans can feel uncertainty. They know when they do not know or remember, and they respond well to uncertainty by deferring response and seeking information," Smith writes in the September issue of the journal Trends in Cognitive Sciences. And accumulating research, he says, suggests metacognition is not unique to humans. Story continues below ↓advertisement | your ad here "The idea is that some minds have a cognitive executive that can look in on the human's or the animal's thoughts and problem-solving and look at how its going and see if there are ways to guide it or if behavior needs to pause while more information is obtained," Smith told LiveScience. Robert Hampton, assistant professor of psychology at Emory University in Georgia, who studies neuroscience and animal behavior, agrees that some animals show metacognition. "Work with primates has shown many parallels with human metacognitive performance," said Hampton, who was not involved in the current review study. "In particular, some of the studies done by Dr. Smith and colleagues have shown close correspondence between the performance of humans and monkeys in nearly identical metacognitive tests." © 2009 LiveScience.com.

Keyword: Attention
Link ID: 13274 - Posted: 06.24.2010

By Daniele Seiss I did it, I thought in disbelief, and I even sprinted at the end. Did anyone notice, I wondered. I somehow managed to find it in me to sprint across the finish line. Then I tried not to collapse right there on the road. My body ached, and after hours of sweating, I was quickly becoming chilled in the 50-degree wind. Desperately trying to keep moving, I suddenly found myself in a crowd of post-marathoners shuffling slowly, cattlelike, along a barricaded corridor, as volunteers handed out water and enshrouded us with thin mylar blankets and then others handed us medals, all alike, to commemorate our run. This should have been my greatest hour. After all, I had secured the grail of marathons, the holy Boston, something I had been dreaming about for years. Yet it seemed strangely pointless, so after-the-fact, so anticlimactic. And then it dawned on me. Finishing the Boston Marathon was nothing in comparison to the real hurdle I'd been able to surmount and the one that had turned me into a runner in the first place: major lifelong depression. Long before Boston, in fact, running had saved my life. I can't even say for certain when dark thoughts started to take control of my life. But I remember, when I was just 6 years old, crying every day. I didn't sleep at night. When I did, I had nightmares. I stopped eating. When I did eat, I often couldn't keep the food down. I felt that something terrible was going to happen, to my parents or to me. I was soon plagued by bad headaches. The condition became severe, and I began to develop paranoid thoughts and panic attacks, though at the time no one, including me, would recognize that's what was going on. © 2009 The Washington Post Company

Keyword: Depression
Link ID: 13273 - Posted: 06.24.2010

By Katherine Harmon From polite petitions to fierce fires, activists opposed to animal research have made their position clear in the U.S. and abroad for many years. But now, medical researchers are being encouraged to press on—and speak out. Two new commentaries, published online today in The Journal of Neuroscience, highlight recent threats that have befallen some researchers who perform research on animals. "We have seen our cars and homes firebombed or flooded, and we have received letters packed with poisoned razors and death threats via e-mail and voicemail," Dario Ringach of the David Geffen School of Medicine and J. David Jentsch of the University of California Los Angeles (UCLA) wrote in one of the papers. "These threats do not endanger just these individuals alone, but also the scientific community at large and the health and well-being of millions affected by their research," Thomas Carew, president of The Society of Neuroscience (SfN), said in a prepared statement responding to the commentaries. "Today, it is unacceptable that in the pursiut of better health and understanding of disease, researchers, their families, and their communities face violence and intimidation by extremists." "Responsible research has played a vital role in nearly every major medical advance of the last century, from heart disease to polio, and is essential to future advances," Carew continued. Animal rights groups, however, maintain that most drugs developed and tested on animals never pass human safety or efficacy trials and never make it to market. © 1996-2009 Scientific American Inc.

Keyword: Animal Rights
Link ID: 13272 - Posted: 06.24.2010

Depression can damage a cancer patient's chances of survival, a review of research suggests. The University of British Columbia team said the finding emphasised the need to screen cancer patients carefully for signs of psychological distress. The study, a review of 26 separate studies including 9,417 patients, features in the journal Cancer. It found death rates were up to 25% higher in patients showing symptoms of depression. In patients actually diagnosed with major or minor depression, death rates were up to 39% higher. The increased risks remained even after other clinical characteristics that might affect survival were taken into consideration. However, the researchers said more research was needed before any definitive conclusions could be drawn, as it was difficult to rule out the impact of other factors. They also stressed that, overall, the increased risk of dying from cancer due to depression was small - so patients should not feel they had to maintain a positive attitude to beat their disease. The studies looked at by the British Columbia team focused on a range of survival times, from one year to 10 years. The researchers could find no firm evidence to show that depression impacted on the progression of disease - although the number of studies which specifically looked at this was very limited. Research on animals has suggested that stress can have an effect on tumour growth and the spread of cancer to other parts of the body. It is possible that depression could have an impact on hormones or the immune system, or that depressed people tend to engage in behaviour which might affect how long they live. (C)BBC

Keyword: Depression; Neuroimmunology
Link ID: 13271 - Posted: 09.14.2009

From left are Matt Birk, Lofa Tatupu and Sean Morey, who agreed to donate their brains after death to a Boston University medical school program that studies sports brain injuries.From left are Matt Birk, Lofa Tatupu and Sean Morey, who agreed to donate their brains after death to a Boston University medical school program that studies sports brain injuries. (Associated Press) Three active NFL players will donate their brains after death to a Boston University medical school program that studies sports brain injuries. Centre Matt Birk of the Baltimore Ravens, linebacker Lofa Tatupu of the Seattle Seahawks and receiver Sean Morey of the Arizona Cardinals join 40 retired NFL players already in the program's brain donation registry, the university announced Monday. "One of the most profound actions I can take personally is to donate my brain to help ensure the safety and welfare of active, retired, and future athletes for decades to come," Morey said. The program takes brain and spinal cord tissue donations so researchers can better understand the long-term effects of repeated concussions. Brain trauma is a growing health concern, after the discovery of the neurodegenerative disease chronic traumatic encephalopathy in a number of athletes. The condition can lead to memory loss, emotional instability, erratic behaviour, depression and impulse control problems, and can gradually lead to dementia and in some cases death. The disease results from repetitive trauma to the brain. © CBC 2009

Keyword: Brain Injury/Concussion
Link ID: 13270 - Posted: 06.24.2010

By Terry J. Allen Researchers investigating a deadly disease cluster near a New Hampshire lake are tracking clues that stretch from a delicacy eaten on Guam to a 3.5 billion-year-old type of bacteria and the green scum that coats many New England waters. The scum - blooms of cyanobacteria often misnamed blue-green algae - produces a toxin that doctors at Dartmouth-Hitchcock Medical Center in Lebanon, N.H., suspect might have triggered cases of amyotrophic lateral sclerosis along the north shore of nearby Mascoma Lake. Using patient records and mapping software, the Dartmouth-Hitchcock team looked for ALS clusters in Maine, New Hampshire, and Vermont. Their preliminary data suggest that the disease, also known as Lou Gehrig’s disease, is about 2.5 times more prevalent among people who live within a half-mile of water bodies with past or current cyanobacteria colonies. The incidence of ALS was highest near Mascoma Lake, where nine patients have been diagnosed since 1990, all but one since 2000 - a rate at least 10 times the US average of two in 100,000 people diagnosed annually. The neurodegenerative disease eventually immobilizes patients and, inevitably, destroys their ability to swallow and breathe. In one survey, doctors said ALS is the diagnosis they most dread giving. © 2009 NY Times Co.

Keyword: ALS-Lou Gehrig's Disease ; Neurotoxins
Link ID: 13269 - Posted: 06.24.2010

By Siri Carpenter Early birds may get the best worms—or at least the best garage sale deals—but they also tire out more quickly than night owls do. In a new study researchers Christina Schmidt and Philippe Peigneux, both at the University of Liège in Belgium, and their colleagues first asked 16 extreme early risers and 15 extreme night owls to spend a week following their natural sleep schedule. Then subjects spent two nights in a sleep lab, where they again followed their preferred sleep patterns and underwent cognitive testing twice daily while in a functional MRI scanner. An hour and a half after waking, early birds and night owls were equally alert and showed no difference in attention-related brain activity. But after being awake for 10 and a half hours, night owls had grown more alert, performing better on a reaction-time task requiring sustained attention and showing increased activity in brain areas linked to attention. More important, these regions included the suprachiasmatic area, which is home to the body’s circadian clock. This area sends signals to boost alertness as the pressure to sleep mounts. Unlike night owls, early risers didn’t get this late-day lift. Peigneux says faster activation of sleep pressure appears to prevent early birds from fully benefiting from the circadian signal, as evening types do. © 1996-2009 Scientific American Inc.

Keyword: Biological Rhythms; Attention
Link ID: 13268 - Posted: 06.24.2010

By NATALIE ANGIER Should anybody in the reliably pestilent health care debate be casting about for a mascot organ to represent some of the biggest medical crises that we Americans face, allow me to nominate a nonobvious candidate: the pancreas. It may lie in the hidden depths of the abdominal cavity, and its appearance, size and purpose may be obscure to the average person. Yet the pancreas turns out to be a linchpin in two epidemics that are all too familiar. As the organ entrusted with the manufacture of insulin and other hormones that help control blood sugar, the pancreas gone awry is a source of diabetes, which afflicts more than 23 million people in this country, including the newest member of the Supreme Court. And as the tireless brewer of digestive juices that help shear apart the amalgamated foodstuffs that we consume each day, the pancreas is at the frontlines of our expanding waistlines, the mass outbreak of fatness that has already claimed 60 percent of Americans and shows no sign of slackening. Researchers are discovering that the pancreas helps mediate much of the appetite-related cross talk between the brain and the gastrointestinal tract, the streams of chemical signals that say, I’m starving down here, how about some dinner, or, enough already, step away from that dessert cart and no one will be hurt. By better understanding the precise role of the pancreas in conveying sensations of hunger or satiety, suggested Rodger A. Liddle of Duke University Medical School, we may find new ways to combat obesity. Copyright 2009 The New York Times Company

Keyword: Obesity; Hormones & Behavior
Link ID: 13267 - Posted: 06.24.2010

by Linda Geddes High cholesterol isn't just bad for the heart – it could also make it harder for women to become sexually aroused. That might mean that cholesterol-lowering drugs like statins would help to treat so-called female sexual dysfunction (FSD). Hyperlipidemia, or raised levels of cholesterol and other fats in the blood, is associated with erectile dysfunction in men, because the build-up of fats in blood vessel walls can reduce blood flow to erectile tissue. Since some aspects of female sexual arousal also rely on increased blood flow to the genitals, Katherine Esposito and her colleagues at the Second University of Naples in Italy compared sexual function in premenopausal women with and without hyperlipidemia. Women with hyperlipidemia reported significantly lower arousal, orgasm, lubrication, and sexual satisfaction scores than women with normal blood lipid profiles. And 32 per cent of the women with abnormal profiles scored low enough on a scale of female sexual function to be diagnosed with FSD, compared with 9 per cent of women without normal levels. Women's sexual desire was not affected by hyperlipidemia, however. In a separate paper, Annamaria Veronelli at the University of Milan, Italy, and her colleagues found that female sexual dysfunction was also associated with diabetes, obesity and an underactive thyroid gland. "These two papers suggest that there are strong connections between women's sexual arousal and organic diseases in the same way that men's sexual problems arise," says Geoffrey Hackett, a urologist at the Holly Cottage Clinic in Fisherwick, UK. "This is currently not even considered in women." © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 13266 - Posted: 06.24.2010

US researchers have pinned down new differences in the brain chemistry of people with attention deficit hyperactivity disorder (ADHD). They found ADHD patients lack key proteins which allow them to experience a sense of reward and motivation. The Brookhaven National Laboratory study appears in the Journal of the American Medical Association. It is hoped it could help in the design of new ways to combat the condition. Previous research looking at the brains of people with ADHD had uncovered differences in areas controlling attention and hyperactivity. But this study suggests ADHD has a profound impact elsewhere in the brain too. Researcher Dr Nora Volkow said: "These deficits in the brain's reward system may help explain clinical symptoms of ADHD, including inattention and reduced motivation, as well as the propensity for complications such as drug abuse and obesity among ADHD patients." The researchers compared brain scans of 53 adult ADHD patients who had never received treatment with those from 44 people who did not have the condition. All of the participants had been carefully screened to eliminate factors which could potentially skew the results. Using a sophisticated form of scan called positron emission tomography (PET), the researchers focused on how the participants' brains handled the chemical dopamine, a key regulator of mood. In particular they measured levels of two proteins - dopamine receptors and transporters - without which dopamine cannot function effectively to influence mood. ADHD patients had lower levels of both proteins in two areas of the brain known as the nucleus accumbens and midbrain. (C)BBC

Keyword: ADHD; Drug Abuse
Link ID: 13265 - Posted: 09.12.2009

How could something that feels so good — a long night's sleep — have negative consequences? Unfortunately, that is one possibility that results of a new study suggest: Older adults who sleep nine or more hours each day may have a higher risk of developing dementia than those who spend fewer hours in bed. Spanish researchers found that among nearly 3,300 older adults they followed for three years, those who slept nine or more hours per day, daytime naps included, were about twice as likely to develop dementia as those who typically slept for seven hours. These "long sleepers" were at increased risk even when the researchers accounted for several factors that can affect both sleep and dementia risk — including age, education, and smoking and drinking habits. Story continues below ↓advertisement | your ad here Still, the findings show only an association between longer sleep and dementia, and do not prove that extra hours in bed, per se, contribute to mental decline. "It remains to be established how the relation between longer sleep duration and dementia is mediated," Dr. Julian Benito-Leon, of University Hospital '12 de Octubre' in Madrid, told Reuters Health in an email. One possibility, according to Benito-Leon, is that increased fatigue and sleep is an initial sign of early dementia in some people. Another theory is that one or more underlying health problems may increase older adults' need for sleep, as well as contribute to dementia. The breathing disorder sleep apnea, for instance, causes fatigue and has been linked to impairments in thinking and memory in older adults. Copyright 2009 Reuters.

Keyword: Sleep; Alzheimers
Link ID: 13264 - Posted: 06.24.2010

By Steve Connor, Science Editor A natural chemical found in the sweat of men has been shown to act as a primitive love potion that increases their attractiveness in the eyes of women, a study has found. The substance, which is derived from the male sex hormone testosterone, has a small but significant effect on judgements made by women in a speed-dating situation of a male stranger's attractiveness. Tamsin Saxton of the University of St Andrews studied the influence of androstadienone by dabbling a drop of it on the upper lip of 50 women who took part in the evening trial before they "dated" a series of men. Women of all ages rated the men slightly higher on a scale of attractiveness when given the substance, compared to water or clove oil, but the effect was greatest in younger women aged between 18 and 22, Dr Saxton said. "For some of the women we gave them androstadienone and we put it in clove oil solution so they just smelt clove oil. Some of the women had clove oil alone, and the third group had just water so there was no odour at all," she told the British Science Festival. "We got the women to mark how attractive they thought the men were on a one to seven scale after they interacted with each man," she said. ©independent.co.uk

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 13263 - Posted: 06.24.2010

By SANDRA BLAKESLEE Researchers are reporting that they have solved a longstanding mystery about the rapid spread of a fatal brain infection in deer, elk and moose in the Midwest and West. The infectious agent, which leads to chronic wasting disease, is spread in the feces of infected animals long before they become ill, according to a study published online Wednesday by the journal Nature. The agent is retained in the soil, where it, along with plants, is eaten by other animals, which then become infected. The finding explains the extremely high rates of transmission among deer, said the study’s lead author, Dr. Stanley B. Prusiner, director of the Institute for Neurodegenerative Diseases at the University of California, San Francisco. First identified in deer in Colorado in 1967, the disease is now found throughout 14 states and 2 Canadian provinces. It leads to emaciation, staggering and death. Unlike other animals, Dr. Prusiner said, deer give off the infectious agent, a form of protein called a prion, from lymph tissue in their intestinal linings up to a year before they develop the disease. By contrast, cattle that develop a related disease, mad cow, do not easily shed prions into the environment but accumulate them in their brains and spinal tissues. There is no evidence to date that humans who hunt, kill and eat deer have developed chronic wasting disease. Nor does the prion that causes it pass naturally to other animal species in the wild. Copyright 2009 The New York Times Company

Keyword: Prions
Link ID: 13262 - Posted: 06.24.2010