Katharine Sanderson Special properties of mouse urine are being harnessed to build artificial noses — devices that can sniff out trace quantities of explosives or pollutants, or pick out different smells for food quality control. Electronic noses currently on the market use materials that change their physical properties when the target molecule is caught on them. Some polymers, for example, change their conductivity when a small molecule such as ammonia binds to their surface. But these materials are sometimes not very sensitive, tend to degrade over time, and are generally suitable only for niche applications. Krishna Persaud from the University of Manchester, UK, turned to mouse urine because of the high concentrations of small and hardy major urinary proteins (MUPs) it contains. These proteins can hold scent molecules tightly and release them slowly — a handy trick for mice marking their territory. Similar proteins are found in mice and other animals’ noses to help them detect odours. Persaud recreated mice MUPs and coated them on a quartz-crystal microbalance — a device that has been used in sensors for many years. The crystals used in these devices vibrate at a specific frequency when a current runs through them. If the mass of the crystal changes — by a small molecule landing on it and attaching to the protein coat, for example — so does the vibration frequency, which can be measured. These devices are sensitive to just a few nanograms and can detect molecules at concentrations of a few parts per million. © 2008 Nature Publishing Group

Keyword: Chemical Senses (Smell & Taste)
Link ID: 11612 - Posted: 06.24.2010

Prions have traditionally been linked with the development of Creutzfeld-Jakob Disease (CJD), the brain-wasting equivalent of mad cow disease (also known as bovine spongiform encephalopathy). (CBC)Prions — infectious agents that cause diseases like the human variant of mad cow disease — also have protective properties, new research suggests. When functioning normally, prion proteins protect neurons in the brain from becoming overstimulated and dying, indicates the study, published in the May 5 issue of the Journal of Cell Biology. Prions have traditionally been linked with the development of neurodegenerative diseases like Creutzfeld-Jakob Disease (CJD), the brain-wasting equivalent of mad cow disease (also known as bovine spongiform encephalopathy, or BSE). In this role, abnormal prions cause plaques to form on the neurons preventing them from functioning properly. Researchers at Rockefeller University discovered that when they removed prion proteins from the brain cells of mice, their neurons overreacted to electrical and drug-induced stimulation, eventually dying. The authors believe that prion proteins only turn deadly when they are physically altered, as they can no longer regulate the behaviour of the neurons and offer a neuroprotective effect. Researchers aren't sure how this transformation occurs. © CBC 2008

Keyword: Prions
Link ID: 11611 - Posted: 06.24.2010

Mike Stobbe -- People who sleep fewer than six hours a night -- or more than nine -- are more likely to be obese, according to a new government study that is one of the largest to show a link between irregular sleep and big bellies. The study also linked light sleepers to higher smoking rates, less physical activity and more alcohol use. The research adds weight to a stream of studies that have found obesity and other health problems in those who don't get proper shuteye, said Dr. Ron Kramer, a Colorado physician and a spokesman for the American Academy of Sleep Medicine. "The data is all coming together that short sleepers and long sleepers don't do so well," Kramer said. The study released Wednesday is based on door-to-door surveys of 87,000 U.S. adults from 2004 through 2006 conducted by the National Center for Health Statistics, part of the Centers for Disease Control and Prevention. Such surveys can't prove cause-effect relationships, so -- for example -- it's not clear if smoking causes sleeplessness or if sleeplessness prompts smoking, said Charlotte Schoenborn, the study's lead author. © 2008 Discovery Communications, LLC

Keyword: Sleep; Obesity
Link ID: 11610 - Posted: 06.24.2010

Peter Aldhous Fathers get the baby blues too and, if they do, it can be bad news for their children's language development. Two-year-olds have a smaller vocabulary if their fathers have depression than if their mothers do. Postnatal depression in women is widely recognised and linked to emotional and behavioural difficulties in their children. Less well known is that some men also become depressed soon after a child is born. To explore the effects of paternal depression, a team led by paediatric psychologist James Paulson at the Eastern Virginia Medical School in Norfolk surveyed about 5000 families enrolled in the Early Childhood Longitudinal Study, which is backed by the US Department of Education and records symptoms of depression in parents. When the children were 9 months old, 14 per cent of the mothers and 10 per cent of the fathers were clinically depressed - about twice the rates in the general population. The surprise came when the researchers looked at whether this affected what proportion of 50 common words the children were using at 2 years of age. On average, the kids used 29. But significantly, while postnatal depression had no effect on vocabulary, 9-month-olds with depressed dads went on to use 1.5 fewer words at age 2 than those whose fathers were fine. © Copyright Reed Business Information Ltd.

Keyword: Depression; Development of the Brain
Link ID: 11609 - Posted: 06.24.2010

By Rick Weiss Four decades after scientists showed that migratory birds use Earth's magnetic field to orient themselves during their seasonal journeys, researchers have at last found a molecular mechanism that may explain how they do it. The work, described online yesterday in the journal Nature, was conducted in a test tube and does not prove that birds actually use the mechanism. And researchers aligned with a competing model say they are not convinced. But by identifying for the first time a molecule that reacts to very weak magnetic fields, the experiments prove the plausibility of a long-hypothesized method of avian navigation that has had a credibility problem because no one had ever found a molecule with the required sensitivity. "This is a proof of principle that a chemical reaction can act as a magnetic compass," said Peter Hore of the University of Oxford, who with fellow chemist Christiane Timmel led the research. Hore is testing similar molecules, called cryptochromes, isolated from the eyes of migratory birds. Devens Gust, a chemist at Arizona State University who worked with Hore and Timmel, said the molecules "seem to have the right structural and chemical features to allow them to show this effect." © 2008 The Washington Post Company

Keyword: Animal Migration
Link ID: 11608 - Posted: 06.24.2010

By R. Douglas Fields Hospitals and airplanes ban the use of cell phones, because their electromagnetic transmissions can interfere with sensitive electrical devices. Could the brain also fall into that category? Of course, all our thoughts, sensations and actions arise from bioelectricity generated by neurons and transmitted through complex neural circuits inside our skull. Electrical signals between neurons generate electric fields that radiate out of brain tissue as electrical waves that can be picked up by electrodes touching a person's scalp. Measurements of such brainwaves in EEGs provide powerful insight into brain function and a valuable diagnostic tool for doctors. Indeed, so fundamental are brainwaves to the internal workings of the mind, they have become the ultimate, legal definition drawing the line between life and death. Brainwaves change with a healthy person's conscious and unconscious mental activity and state of arousal. But scientists can do more with brainwaves than just listen in on the brain at work-they can selectively control brain function by transcranial magnetic stimulation (TMS). This technique uses powerful pulses of electromagnetic radiation beamed into a person's brain to jam or excite particular brain circuits. Although a cell phone is much less powerful than TMS, the question still remains: Could the electrical signals coming from a phone affect certain brainwaves operating in resonance with cell phone transmission frequencies? After all, the caller's cerebral cortex is just centimeters away from radiation broadcast from the phone's antenna. Two studies provide some revealing news. © 1996-2008 Scientific American Inc.

Keyword: Miscellaneous
Link ID: 11607 - Posted: 06.24.2010

By Molly Webster Let's do some sleep math. You lost two hours of sleep every night last week because of a big project due on Friday. On Saturday and Sunday, you slept in, getting four extra hours. Come Monday morning, you were feeling so bright-eyed, you only had one cup of coffee, instead of your usual two. But don't be duped by your apparent vim and vigor: You're still carrying around a heavy load of sleepiness, or what experts call "sleep debt"—in this case something like six hours, almost a full nights' sleep. Sleep debt is the difference between the amount of sleep you should be getting and the amount you actually get. It's a deficit that grows every time we skim some extra minutes off our nightly slumber. "People accumulate sleep debt surreptitiously," says psychiatrist William C. Dement, founder of the Stanford University Sleep Clinic. Studies show that such short-term sleep deprivation leads to a foggy brain, worsened vision, impaired driving, and trouble remembering. Long-term effects include obesity, insulin resistance, and heart disease. And most Americans suffer from chronic deprivation. A 2005 survey by the National Sleep Foundation reports that, on average, Americans sleep 6.9 hours per night—6.8 hours during the week and 7.4 hours on the weekends. Generally, experts recommend eight hours of sleep per night, although some people may require only six hours of sleep while others need ten. That means on average, we’re losing one hour of sleep each night—more than two full weeks of slumber every year. © 1996-2008 Scientific American Inc.

Keyword: Sleep
Link ID: 11606 - Posted: 06.24.2010

By Jennifer Couzin Can fat--even a lot of it--be healthy? A provocative study of fat transplants in mice suggests for the first time that the answer may be yes. Although some kinds of fat are known to be worse than others, no one had directly investigated whether certain types of fat might be a good thing. Researchers say that the work is preliminary but intriguing. For most overweight people, excess fat sits in one of two areas: deep inside the abdomen (visceral fat) or around the hips and legs (subcutaneous fat). Researchers have recognized for some time that visceral fat is the greater evil. People with lots of it are much more prone to diabetes, heart disease, and other problems than people with excess subcutaneous fat. But it's not clear exactly why. Is the fat itself different, or does its location in the body matter? To probe this question, C. Ronald Kahn, director of obesity research at the Joslin Diabetes Center in Boston, and his colleagues devised a relatively simple experiment. They transplanted fat in 42 naturally plump, healthy mice. The mice were divided into four groups that underwent different types of operations. In some, the researchers added visceral or subcutaneous fat to the abdomen. In others, they tucked visceral fat or subcutaneous fat under the animals' flanks, the rough equivalent to the hips. Thirteen other animals formed a control group; they were operated on but didn't receive extra fat. © 2008 American Association for the Advancement of Science.

Keyword: Obesity
Link ID: 11605 - Posted: 06.24.2010

Can Double Hearing Eric Bland -- A device screwed into the skull that transmits sound via bone can improve hearing in patients with certain kinds of hearing loss by as much as 50 percent, according to the largest study of devices, known as bone-assisted (or bone-anchored) hearing aids, or BAHAs. "This is a very important technology for a number of patients who have difficulty hearing," said Daniel Lee, a doctor at the Massachusetts Ear and Eye Infirmary in Boston, Mass., who was not involved in the study. "Patients are getting better choices for improving their hearing," said V. Suzanne Jeter, a researcher at Loyola University who presented the study at the 10th International Conference on Cochlear Implants and Other Implantable Auditory Technologies in San Diego. BAHAs have been used for years to restore hearing to patients who suffer from outer and middle ear problems like tumors, chronic infection, congenital disorders and other problems that stop sound from entering the inner ear. Unlike cochlear implants, the device cannot help deaf patients whose inner ear, which contains three tiny bones that contribute to hearing, has been damaged or destroyed. © 2008 Discovery Communications, LLC.

Keyword: Hearing
Link ID: 11604 - Posted: 06.24.2010

Alison Motluk Early child abuse may forever change the way genes are expressed in the brain, suggests a postmortem study of people who died by suicide. It is now well established that it isn't just what genes we inherit, but how they are turned on and off that influences our development. Most of these control switches are thrown before we are born, but some are set in early life, and to a lesser degree, throughout our lives. Genes are switched off when methyl groups are added to our DNA. Studies have shown that diet, stress and even maternal care can influence these "epigenetic" changes. In 2004, for instance, Moshe Szyf and his colleagues at McGill University in Montreal showed that rat pups neglected by their mothers had different levels of methylation and different stress responses from those that were well-cared for. They also showed that, with careful interventions, this could be reversed. Could early care in humans also affect methylation levels? Szyf knew that a sizable proportion of people who commit suicide were abused or neglected early in life. So his team examined the brains of 13 suicide victims who had a history of early neglect or abuse, and compared them to 11 age and gender matched controls, who had had normal upbringings but had died in sudden accidents. © Copyright Reed Business Information Ltd.

Keyword: Stress; Depression
Link ID: 11603 - Posted: 06.24.2010

Heidi Ledford It’s a classic mistake: you arrive at the grocery store hungry, and everything seems irresistible. Researchers have now worked out how a hunger-induced hormone called ghrelin can make all that food seem so desirable. The hormone stimulates the same ‘reward centres’ of the brain that have been linked to drug-seeking behaviour, they say. But it also activates regions of the brain involved with making memories: people injected with ghrelin remember pictures of food more clearly a day later. The appetite-stimulating effects of ghrelin are already being tested to see if the hormone can encourage eating in cancer patients. And inhibiting ghrelin has been discussed as one way to treat obesity. But the new results, published this week in Cell Metabolism 1, suggest that drugs that block ghrelin may have unwanted effects on memory, says study author Alain Dagher of McGill University in Montreal, Canada. Ghrelin was already known to trigger hunger: people given a ghrelin injection will pile their plates higher when turned loose on an all-you-can-eat buffet. Patients with the rare genetic disorder Prader-Willi syndrome have abnormally high levels of ghrelin and sometimes eat without ever feeling sated; some evenrupture their stomachs. © 2008 Nature Publishing Group

Keyword: Obesity; Learning & Memory
Link ID: 11602 - Posted: 06.24.2010

Parents of autistic children are twice as likely to have been hospitalized for a serious mental disorder than the parents of children without the disorder, suggests new research. A review of Swedish birth and hospital records by U.S. researchers reveals that if a child is autistic, their parents are twice as likely as other parents to have been hospitalized for a psychiatric disorder like schizophrenia. Depression and personality disorders were more common among mothers of autistic children (1.2 times more likely) than among mothers of non-autistic kids, suggests the study, published in Monday's issue of the journal Pediatrics. The study looked at 1,237 children born between 1977 and 2003 who were diagnosed with autism before age 10. To be deemed autistic, the children all had to have received a diagnosis of autism disorder, Asperger Syndrome or pervasive developmental disorder. Asperger Syndrome is a variant of autism in which individuals often exhibit extensive knowledge of a specific interest. Symptoms of pervasive developmental disorder include impairments in social interaction, imaginative activity, verbal and non-verbal communication skills, and a limited number of interests and activities that tend to be repetitive. © CBC 2008

Keyword: Autism; Genes & Behavior
Link ID: 11601 - Posted: 06.24.2010

By HENRY FOUNTAIN Songbirds have long been studied for insight into how the brain learns motor tasks — in a bird’s case, singing its characteristic song. Juvenile birds babble in screechy random bursts before they eventually develop a tonally and rhythmically precise song. Researchers have long known that a pathway called the high vocal center, or H.V.C., controls adult song, but whether that same pathway is responsible for babbling and changes as the bird ages has been an open question. “The general view that I had and others in the field had is that vocalization at any age is a function of the H.V.C.,” said Michale S. Fee, an associate professor at the Massachusetts Institute of Technology who has studied bird song for about a decade. But Dr. Fee and two graduate students, Dmitriy Aronov and Aaron S. Andalman, have reached a different conclusion. In experiments on zebra finches, they showed that the H.V.C. had no bearing on babbling. Instead, they report in Science, the behavior is controlled by a different circuit, with the tongue-twisting name of lateral magnocellular nucleus of the nidopallium, or LMAN. Copyright 2008 The New York Times Company

Keyword: Animal Communication; Language
Link ID: 11600 - Posted: 06.24.2010

More evidence is being put forward that breastfed babies eventually become more intelligent than those who are fed with formula milk. Canada's McGill University found breastfed babies ended up performing better in IQ tests by the age of six. But the researchers were unsure whether it was related to the breast milk itself or the bond from breastfeeding. The study of nearly 14,000 children is the latest in a series of reports to have found such a positive link. However, one problem has been that some of the research has struggled to identify whether the findings were related to the fact that mothers from more affluent backgrounds were more likely to breastfeed and it was factors related to the family circumstances that was really influencing intelligence. But the latest study attempted to take this into account by following the progress of children born in hospitals in Belarus, some of which ran breastfeeding promotion schemes to boost rates across all groups. They found that those who breastfed exclusively for the first three months - with many also continuing to 12 months - scored an average of 5.9 points higher on IQ tests in childhood. Teachers also rated these children significantly higher academically than control children in both reading and writing, the Archives of General Psychiatry reported. Lead researcher Professor Michael Kramer said: "Long-term, exclusive breastfeeding appears to improve children's cognitive development." (C)BBC

Keyword: Development of the Brain; Intelligence
Link ID: 11599 - Posted: 05.06.2008

Older people who have low levels of Vitamin D may be at a higher risk of depression, a new study has found. The new research shows that people deficient in vitamin D have high levels of parathyroid hormone, which has been linked to depression. The researchers estimate that 13 per cent of all people over 65 are depressed. Dutch scientists measured the blood levels of vitamin D and parathyroid hormones in 1,282 study participants between the ages of 65 and 95. They found that 26 of them were suffering from a major depressive disorder, 169 had minor depression and 1,087 did not suffer from depression. The study found that 38.8 per cent of men and 56.9 per cent of women had insufficient vitamin D levels. In those people who had both major and minor depression, vitamin D levels were 14 per cent lower than in people who did not suffer from depression. © CBC 2008

Keyword: Depression
Link ID: 11598 - Posted: 06.24.2010

By HOWARD MARKEL, M.D. Like most patients assigned to my substance abuse clinic these days, John, a stylish 22-year-old cosmetology student, did not arrive voluntarily. After two drunken driving violations, one in which another motorist was injured, a judge ordered John to attend a weekly recovery group I conduct for young adults facing similar legal troubles. But that was hardly the biggest stick the judge had at his disposal. “This Scram keeps me from even thinking about drinking,” John immediately told me as he raised a pant leg and pointed to a boxy plastic ankle bracelet that looked neither cool nor comfortable. Scram, for Secure Continuous Remote Alcohol Monitor, records the wearer’s alcohol intake by measuring air and perspiration emissions from the skin every hour. It detects blood alcohol levels as low as 0.02 percent, which corresponds to one drink or less an hour, and can even tell when the alcohol was consumed. Once a day, John has to be near a modem so it can transmit data from the last 24 hours to a monitoring agency and his probation officer. Copyright 2008 The New York Times Company

Keyword: Drug Abuse
Link ID: 11597 - Posted: 06.24.2010

By Sandra G. Boodman Bruce Munro wonders how things might have turned out if he hadn't lost it and dialed 911. The retired obstetrician had watched with mounting alarm as his wife, Bettie, seemed to get sicker by the day. For decades her health had been stable, regulated by medicines she took to control her cholesterol, blood pressure, Type 2 diabetes, a thyroid condition and a mood disorder. But in March 2006, Bettie Munro had developed a tremor that became very bad very fast. Doctors assumed she was suffering from a rapidly progressive case of Parkinson's disease, but the neurologist treating her was baffled about why the increasingly potent drugs he prescribed didn't seem to help. On Dec. 22, 2006, while Munro was getting his wife dressed for the day, he snapped. She had fallen three times and could no longer feed herself. "I thought, 'This is it, I can't handle this at home,' " Munro recalled. He picked up the phone and called for help. An ambulance whisked Bettie Munro from their house in a Loudoun County retirement community to Inova Loudoun Hospital. © 2008 The Washington Post Company

Keyword: Movement Disorders; Schizophrenia
Link ID: 11596 - Posted: 06.24.2010

By CARL ZIMMER “Why are humans so smart?” is a question that fascinates scientists. Tadeusz Kawecki, an evolutionary biologist at the University of Fribourg, likes to turn around the question. “If it’s so great to be smart,” Dr. Kawecki asks, “why have most animals remained dumb?” Dr. Kawecki and like-minded scientists are trying to figure out why animals learn and why some have evolved to be better at learning than others. One reason for the difference, their research finds, is that being smart can be bad for an animal’s health. Learning is remarkably widespread in the animal kingdom. Even the microscopic vinegar worm, Caenorhadits elegans, can learn, despite having just 302 neurons. It feeds on bacteria. But if it eats a disease-causing strain, it can become sick. The worms are not born with an innate aversion to the dangerous bacteria. They need time to learn to tell the difference and avoid becoming sick. Many insects are also good at learning. “People thought insects were little robots doing everything by instinct,” said Reuven Dukas, a biologist at McMaster University. Copyright 2008 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 11595 - Posted: 06.24.2010

By ALIYAH BARUCHIN A formerly controversial high-fat diet has proved highly effective in reducing seizures in children whose epilepsy does not respond to medication, British researchers are reporting. As the first randomized trial of the diet, the new study lends legitimacy to a treatment that has been used since the 1920s but has until recently been dismissed by many doctors as a marginal alternative therapy. “This is the first time that we’ve really got Class 1 evidence that this diet works for treatment of epilepsy,” said Dr. J. Helen Cross, professor of pediatric neurology at University College London and Great Ormond Street Hospital. She is a principal investigator on the study, which will appear in the June issue of The Lancet Neurology. Though its exact mechanism is uncertain, the diet appears to work by throwing the body into ketosis, forcing it to burn fat rather than sugar for energy. Breakfast on the diet might consist of bacon, eggs with cheese, and a cup of heavy cream diluted with water; some children drink oil to obtain the fats that they need. Every gram of food is weighed, and carbohydrates are almost entirely restricted. Breaking the diet with so much as a few cookies can cause seizures to flare up. Copyright 2008 The New York Times Company

Keyword: Epilepsy; Obesity
Link ID: 11594 - Posted: 06.24.2010

By EDWARD ROTHSTEIN When it comes to LSD, I have to confess: I inhaled. But I inhaled like so many other denizens of the 1960s and early ’70s, whether they actually took the drug or not. I inhaled because you couldn’t fail to inhale. LSD — its aura if not its substance — was a component of the air we breathed. This hallucinogen infused the exhalations of musicians, philosophers, advertisers and activists. There seemed nothing “counter” about this culture; it was prevalent. At the time there seemed to be as many head shops in New York as there are Starbucks now; acid rock played in those darkened spaces to acid heads, as beams of black light caused DayGlo Op-Art images to shimmer dizzyingly. Typefaces ballooned and swooped, melting across posters and album jackets in drug-induced swoons. Lucy was in the sky with diamonds, the Byrds were eight miles high, the Magical Mystery Tour was overbooked; Carlos Castaneda played out his fantasies. The era’s hallmark drug was championed with as much messianic fervor as the era’s countercultural politics. And I, and seemingly everyone else I knew, ingested that culture even if not the drug itself, not even realizing how strange that culture was. It seems even stranger with the passing of time. So while the death at 102 last week of Albert Hofmann may have tempted some to resurrect tales of spiritual adventures under the influence, or to invoke the now familiar quip that if you can remember the ’60s you weren’t there, there are other flashbacks — LSD-induced or not — to consider. Copyright 2008 The New York Times Company

Keyword: Drug Abuse
Link ID: 11593 - Posted: 06.24.2010