By Kathleen Raven A compound already sitting on the shelves of biomedical laboratories and emergency room supply closets seems to interrupt the formation of neurodegenerative protein clumps found in Huntington’s disease, according to a preliminary animal study published August 7 in the Journal of Neuroscience. This versatile agent, called methylene blue, gets a mention in medical literature as early as 1897 and was used to treat, at one time or another, ailments ranging from malaria to cyanide poisoning. The U.S. Food and Drug Administration has never formally approved it as a therapy for any illnesses. But that fact hasn’t stopped biomedical researchers from tinkering with the agent’s apparent ability to improve cognitive function. And although the new paper out today relies on a Huntington’s disease model in flies and mice, scientists are hopeful. "Because of existing knowledge of methylene blue and the fact that it’s not harmful to humans, I would hope that progress toward clinical trials could go relatively quickly," says Leslie Thompson, a neurobiologist at University of California–Irvine and lead author on the new study. Huntington’s disease occurs when the C-A-G sequence of DNA base pairs repeat too often on the HTT gene, resulting in an abnormally long version of the huntingtin protein, that therefore folds incorrectly and forms clumps in the brain. The illness usually begins to affect people in their 30s and 40s, causing movement problems and early death. No drug is currently available to stop the disease from progressing. © 2012 Scientific American

Keyword: Huntingtons
Link ID: 17168 - Posted: 08.15.2012

by Michael Slezak A lack of anti-Müllerian hormone in boys with autistic spectrum disorder (ASD) may lead to a greater number of symptoms. Michael Pankhurst and Ian McLennan from the University of Otago in New Zealand say hormones like anti-Müllerian hormone (AMH) that control the speed at which the body and brain develop might play a central role in the way that ASD progresses through childhood. The pair analysed the level of AMH in 82 boys with ASD. The lower the level of AMH in their blood, the greater the number of autistic traits they displayed. In an earlier study, McLennan and his colleagues found that an increased level of AMH was associated with slower overall growth and development in boys. Together, he thinks the two studies suggest that a lack of AMH could cause the brain to develop too quickly, leading to an increased number of symptoms in boys with ASD. "Rapid development is associated with a greater frequency of developmental disorders," says McLennan. A complex system that develops quickly is more likely to contain errors than one that develops more slowly, he explains. Surprisingly, there was no difference between the average level of anti-Müllerian hormone in the children with ASD and 16 boys without autism. McLennan says this shows that the hormone doesn't cause ASD, but may increase the number of symptoms in people who have the condition. © Copyright Reed Business Information Ltd.

Keyword: Autism; Hormones & Behavior
Link ID: 17167 - Posted: 08.15.2012

Analysis by Jesse Emspak A glass inspired by spider's webs is being used to keep birds from smacking into windows. Birds can't see glass well, and so many of them die when they hit picture windows. Humans can't see glass well either, which might explain why some people try to walk through glass doors. But most people know that the refection of the sky and landscape in a window isn't real -- unfortunately, birds don't. According to the Fatal Light Awareness Program, a building with glass walls or windows can kill up to 10 birds per day, and estimates of worldwide deaths from such collisions reach hundreds of millions of birds each year. On Lindisfarne Island, off the northeastern coast of England, local authorities wanted to do something about it. Hundreds of species of migratory birds pass through every year. So officials decided to cover a lookout tower with glass designed by Arnold Glas, a German company. Called Ornilux, the glass has a spiderweb-like pattern that humans can't see unless they stand very close (see image below, right). But because glass reflects ultraviolet light, birds can see the pattern very well. Spider webs, particularly those of orb weaver spiders, work the same way, reflecting UV and alerting the bird that there is something there. While flying through a web wouldn't hurt a bird, the bird doesn't know that. So they avoid them. The glass was tested in a flight tunnel in the United States. Birds were allowed to fly to one end of the tunnel which was covered with two types of glass, one with the UV-reflective coating. The birds avoided hitting the coated glass up to 68 percent of the time. © 2012 Discovery Communications, LLC.

Keyword: Vision
Link ID: 17166 - Posted: 08.15.2012

By Susan Milius COLLEGE PARK, Md. — A mantis shrimp, which has one of the most elaborate visual systems ever discovered, turns out to be pretty lousy at distinguishing one color from another. The puzzling underachievement may mean that the mantis shrimp brain perceives color in a way new to science, says Hanne Thoen of the University of Queensland in Brisbane, Australia. She presented results from her ongoing study August 6 at the 10th International Congress of Neuroethology. The stalked eyes of mantis shrimp species that live in shallow water can have up to 16 kinds of photoreceptor cells, 12 of which are specialized for different colors. People make do with four kinds, three of which pick up colors. Yet tests with pairs of increasingly similar colors found that the mantis shrimp Haptosquilla trispinosa flunks out when choices narrow to colors 15 nanometers apart in wavelength, Thoen said. At sweet spots in the color spectrum, people can distinguish between colors only 1 or 2 nanometers apart. “Hanne’s results are a bit of a shock to us,” says Thomas Cronin of the University of Maryland, Baltimore County, whose lab also studies mantis shrimp vision. Thoen tested the color vision of mantis shrimp by training them to scoot out of their burrows toward a pair of optical fibers and punch at the one glowing a particular color. As she narrowed the color gap between the two fibers, she could tell when the animals no longer discerned a difference. © Society for Science & the Public 2000 - 2012

Keyword: Vision; Evolution
Link ID: 17165 - Posted: 08.15.2012

By Michelle Andrews, Alzheimer’s disease can’t be prevented or cured, and it ranks second only to cancer among diseases that people fear. Still, in an international study last year from the Harvard School of Public Health, about two-thirds of respondents from the United States said they would want to know if they were destined to get the disease. Although there are no definitive tests that predict whether most people will get the disease, people sometimes want such information for legal and financial planning purposes or to help weigh the need for long-term-care insurance. Current tests to identify the risk of developing Alzheimer’s disease when no symptoms are present provide only limited information, and health insurance generally doesn’t cover them. But that’s not stopping some people from trying to learn more. Most of the 5 million people who have Alzheimer’s developed it after age 60. In these cases, the disease is likely caused by a combination of genetic, lifestyle and environmental factors. About 5 percent of Alzheimer’s patients have inherited an early-onset form that is generally linked to a mutation on one of three chromosomes. Research suggests that the brain may show signs of Alzheimer’s decades before obvious symptoms appear. Scans can identify the presence of beta-amyloid, a protein that is often deposited in the brains of people with the disease, for example. Changes in proteins in the blood or cerebrospinal fluid may also be associated with Alzheimer’s disease. © 1996-2012 The Washington Post

Keyword: Alzheimers
Link ID: 17164 - Posted: 08.14.2012

By ABBY ELLIN After downing 70 chicken wings in about an hour, Andrew Walen realized he had a problem. Oh, he had known something was wrong over the years. Normal people don’t consume 4,500 calories worth of food in one sitting, or order takeout for four when dining alone. But it took a maniacal feeding frenzy for him to finally accept the reality: He was a binge eater, and he had absolutely no control around food. “Ultimately, it was about numbing out and self-loathing,” said Mr. Walen, now 39 and a therapist in Columbia, Md. “There was this voice in my head that said, ‘You’re no good, worthless,’ and I turned to food.” Mr. Walen is one of an estimated eight million men and women in the United States who struggle with binge eating, defined as consuming large amounts of food within a two-hour period at least twice a week without purging, accompanied by a sense of being out of control. While about 10 percent of patients with anorexia and bulimia are men, binge eating is a problem shared almost equally by both sexes. A study published online in October and then in the March issue of The International Journal of Eating Disorders found that among 46,351 men and women ages 18 to 65, about 11 percent of women and 7.5 percent of men acknowledged some degree of binge eating. “Binge eating among men is associated with significant levels of emotional distress, obesity, depression and work productivity impairment,” said Richard Bedrosian, a study author and director of behavioral health and solution development at Wellness and Prevention Inc., which works with employers and health plans. Copyright 2012 The New York Times Company

Keyword: Anorexia & Bulimia; Sexual Behavior
Link ID: 17163 - Posted: 08.14.2012

Prosthetic retina helps to restore sight in mice Geoff Brumfiel Two neuroscientists have created a prosthesis that can partially restore the sight to blind mice. The device could eventually be developed for use in humans. More than 20 million people worldwide become blind owing to the degeneration of their retina, the thin tissue at the back of the eye that turns light into a neural signal. Only one prosthesis has been approved for treatment of the condition — it consists of an array of surgically implanted electrodes that directly stimulate the optic nerve and allow patients to discern edges and letters. Patients cannot, however, recognize faces or perform many everyday tasks. Sheila Nirenberg, a physiologist at the Weill Medical College at Cornell University in New York thinks that the problem is at least partially down to coding. Even though the retina is as thin as tissue paper, it contains several layers of nerves that seem to encode light into neural signals. "The thing is, nobody knew the code," she says. Without it, Nirenberg believes that visual prostheses will never be able to create images that the brain can easily recognize. Now, she and her student, Chethan Pandarinath, have come up with a code and developed a device that uses it to restore some sight in blind mice. The duo began by injecting nerve cells in the retinas of their mice with a genetically engineered virus. The virus had been designed to insert a gene that causes the cells to produce a light-sensitive protein normally found in algae. When a beam of light was then shown into the eye, the protein triggered the nerve cells to send a signal to the brain, performing a similar function to healthy rod and cone cells. © 2012 Nature Publishing Group

Keyword: Vision; Robotics
Link ID: 17162 - Posted: 08.14.2012

By Bruce Bower An ancient finger bone recently landed a genetic sucker punch on scientists studying human evolution. DNA extracted from this tiny fossil, unearthed in Siberia’s Denisova Cave, unveiled a humanlike population that interbred with people in East Asia at least 44,000 years ago. Denisovans supplied nearly 5 percent of the genes of native groups now living in Australia, New Guinea and on several nearby islands. That molecular shocker followed a revelation that the genetic instruction books of people from Australia to the Americas contain a roughly 2.5 percent contribution from Neandertals, modern humans’ evolutionary cousins that died out around 30,000 years ago. Pulling the DNA shades up on ancient human dalliances with Neandertals and closely related Denisovans has sparked a scientific consensus that members of mobile human groups interbred with closely related populations in the Homo genus during the Stone Age. “The question is no longer ‘When did ancient populations such as Neandertals go extinct?’ but ‘What happened to those populations and to modern humans as a result of interbreeding?’ ” says anthropologist John Hawks of the University of Wisconsin–Madison. Clear signs of interbreeding have left archaeologists and other students of the Stone Age scrambling to revisit existing ideas about Homo sapiens’ evolutionary past. A dominant theory holding that humans evolved in Africa and left on neat one-way routes to Asia and Europe has to be revised. Instead, these ancient people must have followed a tangled web of paths taking them to other continents and sometimes reversing course. During these travels, humans encountered Neandertals, Denisovans and probably other humanlike populations that were already traipsing interconnected avenues through Asia and Europe. © Society for Science & the Public 2000 - 2012

Keyword: Evolution
Link ID: 17161 - Posted: 08.14.2012

by Carol Cruzan Morton Migraines are a battle of the sexes that women might prefer not winning. Each year, roughly three times more women than men—up to 18% of all women—suffer from the debilitating headaches, as tallied by epidemiological surveys in Europe and the United States. A new brain imaging study may explain the divide: The brains of women with migraines appear to be built differently than those of their male counterparts. To conduct the study, researchers headed by David Borsook, a neurologist and neurobiologist of Boston Children’s Hospital and Harvard Medical School, recruited 44 men and women, half of whom were migraine sufferers. The women who had migraines rated them as being as intense as the men did, but they tended to find them more unpleasant. Borsook says the distinction is analogous to the loudness of fingernails scratching on a chalkboard versus the torment of hearing the sound. The team then scanned the brains of the volunteers. The researchers gathered two kinds of data sets, one that captured brain shapes and features, and one that measured brain activity. Female migraine sufferers showed slightly thicker gray matter in two regions: one, the posterior insula, is well-known in pain processing; the other, the precuneus, has been recently linked to migraines but is more widely known as a fundamental brain hub that may house a person's consciousness or sense of self. The other volunteers, including the male migraine sufferers, did not show this thickening. All of the scans were done when people did not have a migraine. To figure out what those structural changes meant, lead author Nasim Maleki, a medical physicist at Boston Children's Hospital and Harvard Medical School, returned to the MRI scans of only those men and women with episodic migraines. © 2010 American Association for the Advancement of Science.

Keyword: Pain & Touch; Hormones & Behavior
Link ID: 17160 - Posted: 08.14.2012

By NATALIE ANGIER Deseada Parejo, a biologist at the Arid Zones Experimental Research Station in Almería, Spain, was studying family dynamics behavior in Eurasian rollers — spectacular jay-size birds with long, slender tails and the Cray-Pas colors of parakeets. On removing one of the nestlings for a standard check of size and weight, she practically jumped at its horror-film response: The tiny chick gaped its mouth wide and vomited up a big dose of sticky orange liquid, enough to fill half a teaspoon. Dr. Parejo touched a second chick, a third, a sixth, and got the same expulsory retort. “I have worked with many other bird species,” she said, “but I never found anything similar to this vomiting behavior before.” Not only that: The fluid had a distinctive, evolving odor. “It’s like orange juice at first,” she said. “Then it begins to smell like insects, like the prey the parents provide.” In the current issue of Biology Letters, Dr. Parejo and her colleagues describe their study of this noteworthy aroma, which they designate the roller nestlings’ “smell of fear.” The researchers said that while the reflux reflex might well serve as a defense mechanism — helping to repel nest predators like snakes and rodents — they were interested in a different question: whether the parents could detect the olfactory cry of alarm, and if so, how they reacted. The answer to the first question was yes. But the parental response to the eau of offspring terror was anything but heroic; instead, it was a bit like those childhood nightmares, where the louder you cry out to Mom and Dad in a crowd, the faster they leave you behind. © 2012 The New York Times Company

Keyword: Emotions; Chemical Senses (Smell & Taste)
Link ID: 17159 - Posted: 08.14.2012

By Tina Hesman Saey When a cold takes away a person’s sense of smell, part of the brain that helps link odors with memory, emotion and reward works overtime in preparation for the return of air flow. The way smell rebounds from a period of diminished sensory input distinguishes it from the other senses, researchers at the Northwestern University School of Medicine in Chicago report online August 12 in Nature Neuroscience. Other senses tend to back off when their functions are restricted. When a person wears a patch over one eye, for example, the part of the brain devoted to processing information from that eye weakens while the part linked to the other eye grows stronger. The same is true for hearing and touch, such as when a person goes deaf in one ear or loses a finger. To find out what happens to the olfactory system — the part of the brain that processes scents — when it’s completely odor deprived, Northwestern neuroscientist Joanna Keng Nei Wu and her colleagues set up a scent-free zone in a hospital’s research wing. Volunteers had to give up scented toiletries and spend a week with cotton stuffed up their nostrils to seal their noses off from the outside world. The researchers even took away the volunteers’ toothpaste, forcing them to brush with baking soda instead. Despite the hardships, it wasn’t difficult to find willing volunteers, Wu says. “We had a lot of medical students who wanted us to lock them up in the hospital for a week so they could study.” © Society for Science & the Public 2000 - 2012

Keyword: Chemical Senses (Smell & Taste)
Link ID: 17158 - Posted: 08.14.2012

By RUTH PADAWER The night before Susan and Rob allowed their son to go to preschool in a dress, they sent an e-mail to parents of his classmates. Alex, they wrote, “has been gender-fluid for as long as we can remember, and at the moment he is equally passionate about and identified with soccer players and princesses, superheroes and ballerinas (not to mention lava and unicorns, dinosaurs and glitter rainbows).” They explained that Alex had recently become inconsolable about his parents’ ban on wearing dresses beyond dress-up time. After consulting their pediatrician, a psychologist and parents of other gender-nonconforming children, they concluded that “the important thing was to teach him not to be ashamed of who he feels he is.” Thus, the purple-pink-and-yellow-striped dress he would be wearing that next morning. For good measure, their e-mail included a link to information on gender-variant children. When Alex was 4, he pronounced himself “a boy and a girl,” but in the two years since, he has been fairly clear that he is simply a boy who sometimes likes to dress and play in conventionally feminine ways. Some days at home he wears dresses, paints his fingernails and plays with dolls; other days, he roughhouses, rams his toys together or pretends to be Spider-Man. Even his movements ricochet between parodies of gender: on days he puts on a dress, he is graceful, almost dancerlike, and his sentences rise in pitch at the end. On days he opts for only “boy” wear, he heads off with a little swagger. Of course, had Alex been a girl who sometimes dressed or played in boyish ways, no e-mail to parents would have been necessary; no one would raise an eyebrow at a girl who likes throwing a football or wearing a Spider-Man T-shirt. © 2012 The New York Times Company

Keyword: Sexual Behavior; Development of the Brain
Link ID: 17157 - Posted: 08.13.2012

By Karen Weintraub Paul Barney had his first seizure four days after his fourth birthday. By the time he was 10, his mom worried that if they didn’t get the seizures under control soon, he might lose IQ points along with his ready smile. When Brian Manning, 11, had a seizure on the school playground – instead of in his bed as usual – his parents knew it was time for drastic action. He’d already had brain surgery once, but doctors said he might need five or six more operations. Or he could have one, to completely remove the right half of his brain. Both boys have epilepsy and recently underwent surgery at Boston Children’s Hospital. And both represent the promise and frustration of epilepsy treatment today. Patients have more options, and there is more awareness, less stigma, and a better understanding of epilepsy than there has ever been. But available medications can’t control seizures in about one-third of patients, including Paul and Brian, and while surgery is safer, it still comes with high risks. It also remains unclear what causes the electrical disturbance in patients’ brains that triggers seizures. Roughly 1 in 26 Americans will develop epilepsy at some point in life – more than will have autism, AIDS, or Parkinson’s disease. Some patients do fine between seizures and can function normally. In others, their brains are constantly being disrupted, like a radio station filled with static, according to Dr. Blaise Bourgeois the director of the Division of Epilepsy and Clinical Neurophysiology at Boston Children’s. © 2012 NY Times Co.

Keyword: Epilepsy
Link ID: 17156 - Posted: 08.13.2012

By SABRINA TAVERNISE Adolescents in states with strict laws regulating the sale of snacks and sugary drinks in public schools gained less weight over a three-year period than those living in states with no such laws, a new study has found. The study, published Monday in Pediatrics, found a strong association between healthier weight and tough state laws regulating food in vending machines, snack bars and other venues that were not part of the regular school meal programs. Such snacks and drinks are known as competitive foods, because they compete with school breakfasts and lunches. The conclusions are likely to further stoke the debate over what will help reduce obesity rates, which have been rising drastically in the United States since the 1980s. So far, very little has proved effective and rates have remained stubbornly high. About a fifth of American children are obese, according to the Centers for Disease Control and Prevention. Public health experts have urged local and state governments to remove competitive foods from schools, and in recent years states have started to pass laws that restrict their sale, either banning them outright or setting limits on the amount of sugar, fat or calories they contain. The study tracked weight changes for 6,300 students in 40 states between 2004 and 2007, following them from fifth to eighth grade. They used the results to compare weight change over time in states with no laws regulating such food against those in states with strong laws and those with weak laws. © 2012 The New York Times Company

Keyword: Obesity; Development of the Brain
Link ID: 17155 - Posted: 08.13.2012

By Karen Weintraub Dr. Steven E. Hyman, a neuroscientist and former Harvard provost, now directs the Stanley Center for Psychiatric Research at the Broad Institute, which is trying to better understand and develop treatments for conditions like depression, anxiety, schizophrenia, bipolar disorder, ADHD, obsessive-compulsive disorder, and autism. Q. There haven’t been a lot of drugs developed recently to treat these conditions. A. The modern era of neuropsychopharmacology began brilliantly in the early 1950s. There has been enormous progress in making drugs safer and more tolerable. [But effectiveness has not improved substantially.] We’ve reached a fairly unsatisfactory place in the treatment of these devastating illnesses. Q. Big drug companies are now getting out of the business of developing new medications for these conditions. A. The pharmaceutical industry is basically giving up and throwing in the towel. Their exit is both a symptom of the difficulty and a problem. Q. What does this mean for someone with one of these conditions? A. I don’t want to be inappropriately negative. If somebody has OCD or panic disorder or depression, the combination of cognitive behavioral therapy and a well chosen SSRI-like drug [like Prozac] will, for a reasonable fraction of those patients, markedly improve their lives, although there will be side effects and residual symptoms. © 2012 NY Times Co.

Keyword: Schizophrenia; OCD - Obsessive Compulsive Disorder
Link ID: 17154 - Posted: 08.13.2012

By KATIE HAFNER SEATTLE — Dr. Richard Wesley has amyotrophic lateral sclerosis, the incurable disease that lays waste to muscles while leaving the mind intact. He lives with the knowledge that an untimely death is chasing him down, but takes solace in knowing that he can decide exactly when, where and how he will die. Under Washington State’s Death With Dignity Act, his physician has given him a prescription for a lethal dose of barbiturates. He would prefer to die naturally, but if dying becomes protracted and difficult, he plans to take the drugs and die peacefully within minutes. “It’s like the definition of pornography,” Dr. Wesley, 67, said at his home here in Seattle, with Mount Rainier in the distance. “I’ll know it’s time to go when I see it.” Washington followed Oregon in allowing terminally ill patients to get a prescription for drugs that will hasten death. Critics of such laws feared that poor people would be pressured to kill themselves because they or their families could not afford end-of-life care. But the demographics of patients who have gotten the prescriptions are surprisingly different than expected, according to data collected by Oregon and Washington through 2011. Dr. Wesley is emblematic of those who have taken advantage of the law. They are overwhelmingly white, well educated and financially comfortable. And they are making the choice not because they are in pain but because they want to have the same control over their deaths that they have had over their lives. © 2012 The New York Times Company

Keyword: ALS-Lou Gehrig's Disease
Link ID: 17153 - Posted: 08.13.2012

by Krystnell A. Storr Imagine feeling like you’re lifting a 50-kilogram weight just by pulling at thin air. That’s just one of the possible applications of new "smart fingertips" created by a team of nanoengineers. The electronic fingers mold to the shape of the hand, and so far the researchers have shown that they can transmit electric signals to the skin. The team hopes to one day incorporate the devices into a smart glove that creates virtual sensations, fooling the brain into feeling everything from texture to temperature. Scientists have already developed circuits that stimulate our sense of touch. Some are used in Braille readers that allow blind people to browse the Internet. The devices work by sending electric currents to receptors in the skin, which interpret them as real sensations. However, most of these circuits are built on flat, rigid surfaces that can’t bend, stretch, or fold, says Darren Lipomi, a nanoengineer at the University of California, San Diego, who was not involved in the new study. Hoping to create circuits with the flexibility of skin, materials scientist John Rogers of the University of Illinois, Urbana-Champaign, and colleagues cut up nanometer-sized strips of silicon; implanted thin, wavy strips of gold to conduct electricity; and mounted the entire circuit in a stretchable, spider web-type mesh of polymer as a support. They then embedded the circuit-polyimide structure onto a hollow tube of silicone that had been fashioned in the shape of a finger. Just like turning a sock inside out, the researchers flipped the structure so that the circuit, which was once on the outside of the tube, was on the inside where it could touch a finger placed against it. © 2010 American Association for the Advancement of Science

Keyword: Pain & Touch; Robotics
Link ID: 17152 - Posted: 08.13.2012

By Eric Kandel Our attraction to faces, and particularly to eyes, appears to be innately determined. Infants as well as adults prefer to look at eyes rather than other features of a person’s face, and both infants and adults are sensitive to gaze. The direction of a person’s gaze is very important in our processing of the emotions displayed by that person’s face, because the brain combines information from gaze with information from facial expressions. Reginald Adams from Pennsylvania State University and Robert Kleck from Dartmouth College have found that a direct gaze and an expression of happy emotion facilitate the communication and processing of joy, friendliness, and approach-oriented emotions presumably because, as Uta Frith has found, only direct gaze recruits the dopaminergic reward system. In contrast, an averted, sad, or fearful gaze communicates the avoidance-oriented emotions of fear and sadness. Although gaze and facial expression are processed together, other aspects of beauty, such as gender and age, are processed independently. In a biological experiment designed to examine the neural correlates of beauty—that is, the mechanisms in our brain that account for our sense of beauty—John O’Doherty and his colleagues explored the role of the smile. They found that the orbitofrontal (ventrolateral) region of the prefrontal cortex, the region that is activated by reward and thought to be the apex of the representation of pleasure in the brain, is also activated by attractive faces. Moreover, the response of this region is enhanced by the presence of a smile. © 2012 Scientific American,

Keyword: Emotions; Vision
Link ID: 17151 - Posted: 08.13.2012

by Sara Reardon Freedom of information requests have revealed that pregnant women may not have been given all the facts before taking an experimental treatment to prevent female fetuses from being masculinised as a result of a rare genetic disorder. Research has provided some evidence that dexamethasone, a drug normally prescribed to relieve inflammation, can prevent girls with a rare hormonal disease from developing male genitalia and same-sex attraction if they are treated as fetuses. But as yet, no clinical studies show that this treatment is safe, says Alice Dreger of Northwestern University in Evanston, Illinois. She claims that researchers have misled an unknown number of pregnant women into taking the experimental treatment without properly informing them of its risks. Since the 1980s, Maria New of Mount Sinai School of Medicine in New York has studied and popularised the idea of prescribing dexamethasone "off-label" to women at risk of having foetuses with congenital adrenal hyperplasia (CAH). The treatment is now taught as standard practice in medical schools. But because the drug must be given very early in pregnancy before the fetus' gender or CAH status is known, many fetuses are treated unnecessarily. A child with two carrier parents has a one-in-four chance of having the disease, and the treatment only works for girls. There is little research available on the effects of dexamethasone, which mimics a steroid hormone. And because dexamethasone doesn't cure CAH but only prevents masculinisation of girls, it can be difficult to distinguish possible effects of the drug from other treatments the children receive after birth. © Copyright Reed Business Information Ltd.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 17150 - Posted: 08.11.2012

By Tina Hesman Saey If variety lends life flavor, then humans are kicking things up to a previously unrecognized notch on the spice-o-meter. New efforts to decipher the genetic blueprints of thousands of people have turned up more than half a million tweaks in human DNA, many more than scientists expected. Most of these tweaks are new to science, and a majority fall into a class called “rare variants,” found in 0.5 percent of the population or less. Some of the variety recently uncovered is so uncommon that it shows up in people living in a single geographic region, or even in only one person. Despite their limited spread, the newly discovered rare variants could profoundly affect susceptibility to disease or how well drugs work. They may also help researchers reconstruct recent human migrations around the world. For years, scientists have been examining the chemical units of DNA called nucleotides that act as letters in the human genetic instruction book. So researchers thought they had a good handle on how often to expect single-letter changes in the A’s, G’s, T’s and C’s in that book. Such changes stem from errors in copying and are spotted via comparison with some majority-rule blueprint. They can go by terms like “single nucleotide polymorphisms” or “mutations” depending on where and when they show up. When looking at 202 genes predicted to be important in diseases from 14,002 people, John Novembre of the University of California, Los Angeles and colleagues unearthed five times as many rare genetic variants as expected. © Society for Science & the Public 2000 - 2012

Keyword: Genes & Behavior
Link ID: 17149 - Posted: 08.11.2012