By RANDI HUTTER EPSTEIN, M.D. NEW HAVEN — Two floors below the main level of Yale’s medical school library is a room full of brains. No, not the students. These brains, more than 500 of them, are in glass jars. They are part of an extraordinary collection that might never have come to light if not for a curious medical student and an encouraging and persistent doctor. The cancerous brains were collected by Dr. Harvey Cushing, who was one of America’s first neurosurgeons. They were donated to Yale on his death in 1939 — along with meticulous medical records, before-and-after photographs of patients, and anatomical illustrations. (Dr. Cushing was also an accomplished artist.) His belongings, a treasure trove of medical history, became a jumble of cracked jars and dusty records shoved in various crannies at the hospital and medical school. Until now. In June 2010, after a colossal effort to clean and organize the material — 500 of 650 jars have been restored — the brains found their final resting place behind glass cases around the perimeter of the Cushing Center, a room designed solely for them. These chunks of brains floating in formaldehyde bring to life a dramatic chapter in American medical history. They exemplify the rise of neurosurgery and the evolution of 20th-century American medicine — from a slipshod trial-and-error trade to a prominent, highly organized profession. Copyright 2010 The New York Times Company

Keyword: Miscellaneous
Link ID: 14396 - Posted: 08.24.2010

By John Biemer, Special to the Chicago Tribune Catholic nuns are known for their acts of charity, but Sister Adrienne Schmidt has found a way to give beyond the grave: She will donate her brain to science. First, though, she is exercising it in an annual battery of memory tests administered by researchers at Chicago's Rush University. Schmidt, 82, repeats two-digit numbers, then three, four, five, six and seven digits. She names as many animals as she can in a minute. She listens to a 30-second story about a school cafeteria cook who is robbed of $56. Half an hour later, she must repeat as many details as she can. The yearly tests are designed to provide a history of how her brain is aging. When the time comes, Schmidt's brain will join hundreds of others in 38 cooling units in a laboratory at the school's medical center. Schmidt is one of the original participants in Rush University's Religious Orders Study, which began in 1993. It is one of a handful of studies nationwide that uses donated brains with a rich and detailed clinical history gleaned from years of memory tests and physical exams. Funding for the study is slated to run out next year, but researchers are preparing a federal grant proposal in hopes of extending the study five years, because it continues to yield a bounty of results. Copyright © 2010, Los Angeles Times

Keyword: Alzheimers; Learning & Memory
Link ID: 14395 - Posted: 08.24.2010

by Martin Enserink There's a new twist in the ongoing battle over whether a virus is linked to chronic fatigue syndrome (CFS). After the journal held it for 2 months, a study supporting a link between a mouse retrovirus and CFS was published today in the Proceedings of the National Academy of Science (PNAS). Many are still doubtful of the link, but they're impressed by the authors' efforts to ensure accuracy. In the new study, conducted by scientists at the National Institutes of Health (NIH), the U.S. Food and Drug Administration (FDA), and Harvard University, researchers scanned for traces of a virus known as XMRV in samples taken from 37 CFS patients, collected by Harvard Medical School CFS specialist Anthony Komaroff in the mid-1990s. They found evidence for the virus in 32 (87%) of the patients, but in only three out of 44 healthy controls (6.8%). It remains to be seen whether the infection causes the disease or vice versa, says NIH virologist and co-author Harvey Alter—but he's "confident" that the findings are correct. XMRV—less succinctly known as xenotropic murine leukemia virus-related virus—was first implicated for its potential involvement in prostate cancer, a link that's still under intense debate. Then, in a Science paper published last year, a team led by retrovirologist Judy Mikovits of the Whittemore Peterson Institute for Neuro-Immune Disease (WPI) in Reno, Nevada, found evidence of infection in 67% of CFS patients, compared with just 3.4% of healthy controls. But since then, four other papers failed to find the link, or any evidence of XMRV infection in humans at all. The last of the four, by researchers at the U.S. Centers for Disease Control and Prevention (CDC), was also held for a while, at the researchers' request, while they tried to figure out how government labs could come to such opposite conclusions. The CDC paper was eventually published on 1 July in Retrovirology. © 2010 American Association for the Advancement of Science.

Keyword: Stress; Depression
Link ID: 14394 - Posted: 08.24.2010

By Nathan Seppa In case it isn’t already clear that amphetamine abuse is a bad idea, researchers now report that abusers face more than three times the risk of developing a tear in the aorta, the huge artery carrying blood out of the heart. Physicians consider such a tear an emergency with catastrophic potential. The new findings appear in the August American Heart Journal. An aortic tear, also called aortic dissection, brings on “the most horrible chest pain imaginable,” says David Waters, a cardiologist at San Francisco General Hospital and the University of California, San Francisco. “Patients say, ‘I think I’m going to die,’ and they’re right,” he says. Without treatment, the fatality rate is ultimately about 75 percent, according to the Merck Manual Online. In the new study, researchers scanned the medical records of nearly 31 million patients nationwide, ages 18 to 49, who were hospitalized between 1995 and 2007. Codes on these records showed that 3,116 had an aortic dissection. The researchers also took note of codes that revealed amphetamine abuse or dependence. Use of methamphetamines, an increasingly popular street drug, would show up in the codes as amphetamines. Amphetamine abusers faced 3.3 times the risk of developing a torn aorta that nonusers did, the data showed. Researchers calculated that amphetamine abuse or dependence accounted for slightly less than 1 percent of all aortic dissections in the database. © Society for Science & the Public 2000 - 2010

Keyword: Drug Abuse
Link ID: 14393 - Posted: 08.24.2010

Women who report feeling stressed early in their monthly cycle were more likely than those who were less stressed to report more pronounced symptoms before and during menstruation, according to a study by researchers at the National Institutes of Health and other institutions. The association raises the possibility that feeling stressed in the weeks before menstruation could worsen the symptoms typically associated with premenstrual syndrome and menstruation. Women who reported feeling stressed two weeks before the beginning of menstruation were two to four times more likely to report moderate to severe symptoms than were women who did not feel stressed. Premenstrual syndrome (http://www.nichd.nih.gov/health/topics/menstruation_and_the_menstrual_cycle.cfm.)is a group of physical and psychological symptoms occurring around the time of ovulation, which may extend into the early days of menstruation. Symptoms include feelings of anger, anxiety, mood swings, depression, fatigue, decreased concentration, breast swelling and tenderness, general aches, and abdominal bloating. "We were interested in identifying factors that might predict who might be most at risk for having more severe symptoms," said Audra Gollenberg, Ph.D., a postdoctoral fellow in NICHD's Division of Epidemiology, Statistics and Prevention Research. "It may be possible to lessen or prevent the severity of these symptoms with techniques that help women to cope more effectively with stress, such as biofeedback, exercise, or relaxation techniques."

Keyword: Stress; Hormones & Behavior
Link ID: 14392 - Posted: 08.24.2010

By Nicholette Zeliadt Our sleep patterns, eating habits, body temperature and hormone levels are driven by the rhythmic activity of body's circadian clock. Travel across time zones or shift work can knock those rhythms out of whack, possibly leading to sleep problems, bipolar disorder, metabolic syndrome and even cancer. The lack of convenient and reliable methods to monitor the internal clock's activity has severely limited the study of circadian-related disease, but now, scientists report that they can easily track the circadian rhythms by analyzing a person's plucked hairs. The finding could one day help doctors diagnose and treat patients suffering from circadian dysfunction. The body's master clock, located in the brain region called the hypothalamus, is set by light, which activates clock genes that are responsible for keeping this timekeeper ticking correctly. Within the past decade, scientists have discovered that organs outside the brain (such as the skin, liver and pancreas) also keep track of time with 24-hour fluctuations in clock gene expression. Previous studies have attempted to monitor molecular timekeeping in blood cells or in cells lining the mouth, but these approaches are technically challenging. In an attempt to develop a simpler, noninvasive method to clock circadian rhythms, researchers led by Makoto Akashi of the Research Institute for Time Studies at Yamaguchi University in Japan obtained hairs plucked from volunteers' heads or chins and analyzed clock gene expression in hair follicle cells. They report online this week in the Proceedings of the National Academy of Sciences that the patterns of circadian gene expression in the hair follicle cells accurately reflected the subjects' behavioral rhythms, "demonstrating that this strategy is appropriate for evaluating the human peripheral circadian clock." © 2010 Scientific American

Keyword: Biological Rhythms
Link ID: 14391 - Posted: 08.24.2010

by Paul Marks How do you give a robot a sharper sense of smell? By using genetically modified frog cells, according to Shoji Takeuchi, a bioengineer at the University of Tokyo in Japan. Today's electronic noses are not up to the job, he says. Although e-noses have been around for a while – and are used to sniff out rotten food in production lines – they lack accuracy. That's because e-noses use quartz rods designed to vibrate at a different frequency when they bind to a target substance. But this is not a foolproof system, as subtly different substances with similar molecular weights may bind to the rod, producing a false positive. Instead, Takeuchi believes there is nothing quite as good as biology for distinguishing between different biomolecules, such as disease markers in our breath. So he and his team have developed a living smell sensor. First, immature eggs, or oocytes, from the African clawed frog Xenopus laevis were genetically modified to express the proteins known to act as smell receptors. He chose X. laevis cells as they are widely studied and their protein expression mechanism is well understood. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste); Robotics
Link ID: 14390 - Posted: 08.24.2010

Dr. Shelby Freedman Harris and Dr. Michael Thorpy of Montefiore Medical Center respond: Delayed sleep phase disorder and insomnia are two different disorders. Patients with delayed sleep phase disorder, or D.S.P.D., usually have difficulty falling asleep, but once they fall asleep they have no difficulty obtaining a full night’s sleep and typically sleep until late morning or early afternoon. Those with insomnia, on the other hand, may have difficulty falling asleep or staying asleep, wake too early or feel that sleep is not restorative. Most insomnia patients have a combination of these symptoms, such as difficulty falling asleep as well as staying asleep. Insomnia is also usually due to some specific cause, such as a medical or psychiatric disorder like depression. Our bodies are biologically programmed, through circadian rhythms, to sleep at night and be alert during the day. In some people, these rhythms can shift, causing sleep and wake times to fall outside a desired schedule. In delayed sleep phase disorder, the sleep cycle is pushed later into the night, with a delayed natural morning wake time. Many patients with delayed sleep phase disorder consider themselves “night owls.” It’s common for us to delay our sleep and wake times because of late-night parties and other social activities, but this does not mean we have the disorder. People with delayed sleep phase disorder are unable to return to a normal schedule, despite trying, and end up spending a prolonged time in bed awake before falling asleep. If you are able to fall asleep easily on resuming a normal bedtime after a few late nights, then you do not have delayed sleep phase disorder. Copyright 2010 The New York Times Company

Keyword: Sleep; Biological Rhythms
Link ID: 14389 - Posted: 08.23.2010

By Karen Weintraub It was the week the medication didn’t work that convinced Melissa Zolecki. She thinks her son Matthew got a bottle of inactive dummy pills that week by accident. And the change in his behavior was striking. The MIND Institute at the University of California Davis is testing an antibiotic called minocycline against a placebo in 60 children with Fragile X. The Fragile X Research Foundation of Canada is studying the benefits of the same drug in 20 teenagers and young adults. Seaside Therapeutics is testing the drug arbaclofen , which it is calling STX209, against a placebo in 60 children and adults, to determine its safety and an appropriate dose. Some of those study participants will continue on the drug past the initial four-week trial. Roche is testing a similar drug it is calling RO4917523 against a placebo in 60 adults with Fragile X. Novartis recently completed testing the safety and dosing of a drug called AFQ056 against a placebo in 30 adults with Fragile X. Stanford University researchers are testing the drug donepezil, a medication that enhances the function of the brain chemical acetylcholine. This trial includes 50 patients ages 12 to 21. © 2010 NY Times Co.

Keyword: Development of the Brain
Link ID: 14388 - Posted: 08.23.2010

By LARRY O'HANLON Everyone looks better after you've tipped back a pint or two, and now we may know why. It turns out that alcohol dulls our ability to recognize cockeyed, asymmetrical faces, according to researchers who tested the idea on both sober and inebriated college students in England. To find out if alcohol interfered with the ability to distinguish faces where the left and right sides were uneven, he and his colleagues designed an experiment involving images of faces that were tinkered with to make them perfectly symmetrical or subtly asymmetrical. The results of the study were published by Halsey, Joerg Huber, Richard Bufton and A.C. Little in a recent issue of the journal Alcohol. "Over an evening Joerg, Richard and I went out to the university campus bars with a laptop and asked students to participate," Halsey said. Men appear to be less prone to losing this ability than women when drinking. This included students taking a quick breathalyzer test to confirm their alcohol consumption. The students were classified as either sober or intoxicated, then examined the images. © 2010 ABC News Internet Ventures.

Keyword: Drug Abuse; Sexual Behavior
Link ID: 14387 - Posted: 08.23.2010

By Katherine Harmon Children with autism often focus intently on a single activity or feature of their environment. New research might help to explain this behavioral trend, providing evidence that the brains of young people with autism are slower to integrate input coming from more than one sense at the same time. During study of the disorder decades ago, research into these basic tendencies was common. But in subsequent years, scientists have tended to focus more on complex issues, ranging from communication troubles to underlying genetic patterns. Recently, however, more studies have set their sights back on some of the simple processes that most people take for granted, such as sensory intake, as a way to better understand more high-level manifestations, such as social interaction issues. "We believe that these things interact in very significant ways," says Sophie Molholm, an associate professor of neuroscience at Albert Einstein College of Medicine and co-author of a new study about multi-sensory processing. The research, published online August 19 in Autism Research, used electroencephalograms (EEGs) to measure electrical activity in the brain through the scalp of subjects as they encountered various stimuli. Seventeen children (ages six to 16 years) with autism—and 17 age- and IQ-matched normally developing kids—watched a silent video of their choice throughout the testing. Meanwhile, tones and vibrations were administered in random order, sometimes separately, sometimes at the same time. The EEG readings were time-stamped to the stimuli and compared across all of the children to assess brain activity trends during single- and multi-sensory stimulation. Although the video presented visual stimuli, Molholm points out that because it was a consistent exposure throughout the experiments and the EEG readings were set to pick up on the sound and somatosensory stimuli and averaged out over so many tests, it becomes akin to "background brain activity that will sum to zero," she notes. "It's really just something to keep them busy." © 2010 Scientific American,

Keyword: Autism
Link ID: 14386 - Posted: 08.23.2010

By Susan Milius In a long-running war between bats and moths, at least one bat has gotten the upper wing. Western barbastelle bats in Europe typically ping out their echolocation calls softly enough to locate a moth for dinner before the moth hears them coming, says Holger Goerlitz of the University of Bristol in England. It’s the first documented case of a bat species outwitting its prey by quiet stealth, he and his colleagues say online in a Current Biology paper released August 19. The battle between bats and moths has become a classic system for studying the evolution of predators and their prey. In searching for moths, barbastelles echolocate at about the 94 decibel level, roughly the equivalent of a busy highway, Goerlitz reports. This bat version of whispering is 10 to 100 times lower in amplitude than other aerial-hunting bats’ echolocation calls. Those rank more in the range of jet engines and the vuvuzelas blaring at the latest World Cup, Goerlitz says. People can’t hear frequencies high enough to detect any of this bat racket — “quite lucky for us,” Goerlitz says. To measure the loudness of the barbastelle calls, researchers needed to know how far away from a microphone a flying bat was when it pinged. So they set up a microphone array where bats swooped through at night. The slight differences in times that the calls took to reach different microphones let researchers figure out the bat’s position for each of more than 100 calls. © Society for Science & the Public 2000 - 2010

Keyword: Hearing
Link ID: 14385 - Posted: 08.23.2010

By Emily Sohn Chemicals on our produce may contribute to behavior problems in our kids, suggest three new studies. The studies, which looked at a class of pesticides called organophosphates (OP), linked exposure to the chemicals with attention disorders in children, with perhaps the most dramatic impacts to kids who are exposed in the womb and those who are genetically most susceptible. Because pesticide residues linger on fruits and vegetables, the findings suggest that people either buy organic or take the time to wash their produce well. "We don't want women to not eat fruits and vegetables because it's very important to eat them during pregnancy," said Brenda Eskenazi, an epidemiologist and neuropsychologist at the University of California, Berkeley. "I just let water run really thoroughly over fruits, and I rub them so they're clean." Organophosphates are a set of common pesticides that work by attacking the nervous systems of insects. When people are exposed to high levels of the chemicals, they can develop anxiety, confusion impaired concentration, and other serious symptoms. More recently, scientists have started to wonder how chronic exposure at low levels might be affecting people, especially kids, whose nervous systems are still developing. To find out, Eskenazi and colleagues followed up on a long-term study that has tracked more than 300 Mexican-American women in an agriculturally intensive region of California since they first became pregnant in 1999 or 2000. When the women were pregnant, the researchers measured levels of pesticide breakdown products in their urine. More recently, they collected urine samples from the kids and evaluated measures of attention. © 2010 Discovery Communications, LLC.

Keyword: ADHD; Neurotoxins
Link ID: 14384 - Posted: 08.23.2010

By Steve Yanda Across the spectrum of athletics from youth soccer to the National Football League, concussions are one of the most worrisome of injuries: hard to diagnose and even harder to know when an athlete has recovered. Now, in an unusual combination of real sports and their digital imitators, a handful of colleges, including the University of Maryland, are turning to a video game for help. Athletic trainers in College Park and on other campuses are using the Wii Fit video game as an objective and practical -- if unproven -- method of assessing athletes' balance, an important yardstick for determining recovery from concussion. For the past year, Maryland and Ohio State have partnered to conduct research into the reliability of Wii Fit -- an exercise video game played on Nintendo's Wii console, which allows for physical interaction between player and game -- as an effective concussion management instrument. Darryl Conway, Maryland's head athletic trainer, said this will be the third year the school has used components of the game to conduct baseline testing of its athletes' balance. Proponents of using Wii Fit as a tool to examine concussions praise its simplicity and affordability -- not to mention its popularity with student-athletes. "The athletes love it because what we've done is we've incorporated this fun game that they're playing at home into their rehab system," said Tamerah Hunt, director of research at the Ohio State Sports Concussion Program. "But they're also enjoying it at a time when they're injured or at a time when their spirits are down, and they have to come into the athletic training room every day and they have to get all this treatment . . . and it's kind of a reaction of, 'Oh, this is fun.' " © 2010 The Washington Post Company

Keyword: Brain Injury/Concussion
Link ID: 14383 - Posted: 08.20.2010

By GINA KOLATA The failure of a promising Alzheimer’s drug in clinical trials highlights the gap between diagnosis — where real progress has recently been made — and treatment of the disease. It was not just that the drug, made by Eli Lilly, did not work — maybe that could be explained by saying the patients’ illness was too far advanced when they received it. It was that the drug actually made them worse, the company said. And the larger the dose they took, the worse were patients’ symptoms of memory loss and inability to care for themselves. Not only that, the drug also increased the risk of skin cancer. So when Lilly announced on Tuesday that it was ending its large clinical trials of that drug, semagacestat, researchers were dismayed. “Obviously, this is disappointing news, to say the least,” said Dr. Steven Paul, an Alzheimer’s researcher and a recently retired executive vice president at Lilly. Beyond the setback for Lilly, the study raises questions about a leading hypothesis of the cause of Alzheimer’s and how to treat it. The idea, known as the amyloid hypothesis, says the disease occurs when a toxic protein, beta amyloid, accumulates in the brain. The idea is that if beta amyloid levels are reduced, the disease might be slowed, halted or even prevented if treatment starts early enough. The Lilly drug, like most of the more than 100 Alzheimer’s drugs under development, blocks an enzyme, gamma secretase, needed to make beta amyloid. It was among the first shown to breach the blood-brain barrier and reduce levels of beta amyloid in the brain. And, company studies showed, it did reduce amyloid production. Copyright 2010 The New York Times Company

Keyword: Alzheimers
Link ID: 14382 - Posted: 08.20.2010

By HELEN EPSTEIN For the fortunate, pain is temporary and finite, with a clear beginning, middle and end. But for more than 70 million Americans, including Melanie Thernstrom, pain is chronic, and the primary reason that they seek medical care. The medical profession has been slow to recognize this development. There is currently one board-certified pain specialist in the United States for every 25,000 patients, she writes in her new book, “The Pain Chronicles.” That number, however, is likely to grow as pain is redefined not as a symptom but as a disease that “can eventually rewrite the central nervous system, causing pathological changes to the brain and spinal cord, and ... greater pain.” There have been hundreds of books published in the last decades on pain and its management, but none that combine memoir, scholarly research and journalistic reportage in the way Ms. Thernstrom, the author of two previous books, does. A stellar example of literary nonfiction (parts of which first appeared in The New York Times Magazine), the book recounts the author’s own years with chronic pain and the preconceptions she brought to it (including the idea of pain as the price for romantic love); summarizes its social, cultural and medical history; and gives us a reporter’s view of state-of-the-art treatment. The book has a patchwork quilt structure: more than one hundred small captioned patches (or dispatches), organized into five parts and threaded with personal narrative. This invites differently motivated readers to skip or skim. You can chuckle over the aperçus of poets and philosophers like Aristotle, Coleridge, Dickinson, Sontag, and Foucault in the section entitled “Pain as Metaphor.” You can become absorbed, as I was, in the fascinating struggle over the use of anesthesia (and, later, opiates) in “Pain as History,” or play voyeur during absorbing clinical vignettes of “Pain as Disease.” Copyright 2010 The New York Times Company

Keyword: Pain & Touch
Link ID: 14381 - Posted: 08.20.2010

By David Biello Ketamine—a powerful anesthetic for humans and animals that lists hallucinations among its side effects and therefore is often abused under the name Special K—delivers rapid relief to chronically depressed patients, and researchers may now have discovered why. In fact, the latest evidence reinforces the idea that the psychedelic drug could be the first new drug in decades to lift the fog of depression. "We were trying to figure out what ketamine was doing to produce this rapid response," which can take as little as two hours to begin to act, says neuroscientist Ron Duman of the Yale University School of Medicine. So Duman and his colleagues gave a small amount of ketamine (10 milligrams per kilogram of body weight) to rats and watched the drug literally transform the animals' brains. "Ketamine… can induce a rapid increase in connections in the brain, the synapses by which neurons interact and communicate with each other, " Duman says. "You can visually see this response that occurs in response to ketamine." More specifically, as the researchers report in the August 20 issue of Science, ketamine seems to stimulate a biochemical pathway in the brain (known as mTOR) to strengthen synapses in a rat's prefrontal cortex—the region of the brain associated with thinking and personality in humans. And the ketamine helped rats cope with the depression analog experience brought on by forcing the rodents to swim or exposing them to inescapable stress. "Preclinical and clinical studies show that repeated stress or depression can cause a decrease in connections and an atrophy of connections in the same region of the brain," Duman explains, noting that magnetic resonance imaging shows that some depressed patients have a smaller prefrontal cortex as a result. "Ketamine has the opposite effect and can oppose or reverse the effects of depression" for roughly seven days per dose. © 2010 Scientific American

Keyword: Depression; Drug Abuse
Link ID: 14380 - Posted: 08.20.2010

By Kay Lazar New research suggests that athletes who have had multiple head injuries, and possibly others such as military veterans exposed to repetitive brain traumas, may be prone to developing a disabling neurological disease similar to amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig’s disease. A team of researchers from Boston University School of Medicine and the Veterans Administration Hospital in Bedford said yesterday they have pinpointed evidence of a new disease that mimics ALS in the brains of two former National Football League players previously thought to have died of ALS. They also found the new disease in the brain of a deceased professional boxer who was a military veteran. In most cases, ALS strikes people — many in the prime of life — with no apparent rhyme or reason. The progressive nerve disorder, which affects an estimated 30,000 Americans, slowly paralyzes patients while leaving their mind intact. But if this early research is borne out by autopsies of additional athletes and veterans, it would support the idea that an ALS-type illness can be triggered by the traumas of sports and war. “We believe that these three cases are the tip of the iceberg,’’ said neurosurgeon Robert Cantu, who is a codirector of the BU Center for the Study of Traumatic Encephalopathy. “We don’t know whether this is linked to the increased incidence of ALS in the military, who are subject to blasts and other head injuries, but we are concerned that it may be.’’ The findings, the authors speculated, could mean that athletes and some others previously diagnosed with ALS actually had the related syndrome — perhaps even Gehrig himself, the New York Yankees star who is the iconic ALS sufferer. It’s a mystery that will never be solved, however, because Gehrig’s body was cremated. © 2010 NY Times Co

Keyword: ALS-Lou Gehrig's Disease ; Brain Injury/Concussion
Link ID: 14379 - Posted: 08.20.2010

by Michael Balter Why cooperate when you can be selfish? Many animal behaviors are self-centered and apparently evolved to pass on an individual's genes to future generations. Yet cooperative breeding, in which some members of a group help others to raise their young, has evolved independently many times, especially in birds and insects. A new study of birds concludes that parents get more help when they are sexually faithful to each other. Cooperation has been called an evolutionary paradox, and cooperative breeding is relatively rare, with members of only 3% to 10% of bird species helping to raise one another's young. Among the apes, only humans are cooperative breeders, although monkeys such as marmosets and tamarins do it, too. In the 1960s, British biologist William Hamilton proposed that natural selection could favor cooperation if individuals pass on their own genes by helping relatives raise offspring. But Hamilton argued that cooperation can arise only if such helpers are closely related to recipients and if the benefits outweigh the costs. Over the past few years, Jacobus Boomsma, an evolutionary biologist at the University of Copenhagen, has argued that strict monogamous behavior, such as an ant queen mating for life, spurred the evolution of cooperative breeding in some social insects. Monogamy helps fulfill Hamilton's conditions, because all siblings are equally related to each other and to each parent. Promiscuity, on the other hand, leads to many half-siblings and lowers the relatedness of individuals in a group. © 2010 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Evolution
Link ID: 14378 - Posted: 08.20.2010

By Nathan Seppa The prevalence of hearing loss in teenagers rose by nearly one-third in recent years compared with the rate in the 1980s and 1990s, a new study shows. The findings come as a surprise to the study’s authors, who had expected overall hearing to improve thanks to publicity about the risks of exposure to loud music and the advent of childhood vaccines against meningitis and pneumonia that can prevent many ear infections. But in the August 18 Journal of the American Medical Association, the scientists report that the portion of U.S. adolescents aged 12 to 19 with any hearing loss rose from 14.9 percent during the 1988 to 1995 period to 19.5 percent in 2005 and 2006. Researchers based the analysis on information gathered from nearly 3,000 kids in the earlier time frame and more than 1,700 in the later sampling. The findings suggest that as many as 6.5 million teens in the United States now have some hearing loss. The surveys used largely similar questionnaires and standard hearing tests in which “any hearing loss” was defined as a loss of 15 decibels in at least one ear. That is, a person was determined to have some hearing loss if a tone had to be increased by 15 dB or more beyond the standard detection level to be heard at least half the time. Hearing loss of 25 dB or greater is less common, particularly in children. But it also rose, from 3.5 to 5.3 percent, between the study time frames. The rate of hearing loss increased in high — but not low — frequencies, the researchers found. © Society for Science & the Public 2000 - 2010

Keyword: Hearing
Link ID: 14377 - Posted: 08.20.2010