Scientists have identified a group of brain cells which have the power to control appetite and could be a major cause of eating disorders such as obesity. In experiments in rodents, cells called tanycytes were found to produce neurons which specifically regulate appetite. The University of East Anglia researchers say their find means appetite is not fixed at birth. Their study is published in the Journal of Neuroscience. It was previously thought that nerve cells in the brain associated with appetite regulation were generated entirely during an embryo's development in the womb and could not be altered. But the UEA study's discovery of these tanycytes, which act like stem cells, in the brains of young and adult rodents shows that appetite can be modified. Researchers looked in detail at the hypothalamus section of the brain, which is known to regulate sleep, energy expenditure, appetite, thirst and many other critical biological functions. They studied the nerve cells that regulate appetite using a 'genetic fate mapping' technique and found that some cells added neurons to the appetite-regulating circuitry of the mouse brain after birth and into adulthood. BBC © 2013

Keyword: Obesity
Link ID: 17998 - Posted: 04.08.2013

Steve Connor The rise in the number of overweight children in Britain may be as much to do with their genes as their diet and exercise levels, according to a study that has identified a handful of genetic mutations linked with childhood obesity. Scientists have discovered that children with the most severe kinds of obesity are more likely than other children to have one or more of four genetic variations in their DNA, which could influence such things as appetite and food metabolism. The discovery is part of a wider search for the genes involved in increasing a person’s risk of becoming overweight when exposed to an “obesogenic environment” of high-calorie food and inactivity – which is known to affect some people more than others. The study looked at 1,000 children with the most severe form of early-onset obesity, which is highly likely to result in obesity in adulthood. Some of the 10-year-olds in the study weighed between 80kg and 100kg (12.5st-15.7st). Some of the genetic variations revealed by the study were rare but others are relatively common, suggesting an interaction between genetics and environment, which could explain why certain children become obese while others do not even when they share a similar upbringing. Obesity among British children aged between two and ten has risen since 1995 from 10.1 per cent to 13.9 per cent in 2011. This rise cannot be due to a change in genes alone, because it takes many generations to alter the frequency of genetic mutations in the population. © independent.co.uk

Keyword: Obesity; Aggression
Link ID: 17997 - Posted: 04.08.2013

By Neil Bowdler BBC News UK-based scientists have designed an 'intelligent' microchip which they claim can suppress appetite. Animal trials of the electronic implant are about to begin and its makers say it could provide a more effective alternative to weight-loss surgery. The chip is attached to the vagus nerve which plays a role in appetite as well as a host of other functions within the body. Human trials of the implant could begin within three years, say its makers. The work is being led by Prof Chris Toumazou and Prof Sir Stephen Bloom of Imperial College London. It involves an 'intelligent implantable modulator', just a few millimetres across, which is attached using cuff electrodes to the vagus nerve within the peritoneal cavity found in the abdomen. The chip and cuffs are designed to read and process electrical and chemical signatures of appetite within the nerve. The chip can then act upon these readings and send electrical signals to the brain reducing or stopping the urge to eat. The researchers say identifying chemicals rather than electrical impulses will make for a more selective, precise instrument. The project has just received over 7m euros (£5.9m; $9m) in funding from the European Research Council. A similar device designed by the Imperial team has already been developed to reduce epileptic seizures by targeting the same vagus nerve. "This is a really small microchip and on this chip we've got the intelligence which can actually model the neural signals responsible for appetite control," Prof Toumazou told the BBC. BBC © 2013

Keyword: Obesity; Aggression
Link ID: 17965 - Posted: 03.30.2013

By DENISE GRADY The bacterial makeup of the intestines may help determine whether people gain weight or lose it, according to two new studies, one in humans and one in mice. The research also suggests that a popular weight-loss operation, gastric bypass, which shrinks the stomach and rearranges the intestines, seems to work in part by shifting the balance of bacteria in the digestive tract. People who have the surgery generally lose 65 percent to 75 percent of their excess weight, but scientists have not fully understood why. Now, the researchers are saying that bacterial changes may account for 20 percent of the weight loss. The findings mean that eventually, treatments that adjust the microbe levels, or “microbiota,” in the gut may be developed to help people lose weight without surgery, said Dr. Lee M. Kaplan, director of the obesity, metabolism and nutrition institute at the Massachusetts General Hospital, and an author of a study published Wednesday in Science Translational Medicine. Not everyone who hopes to lose weight wants or needs surgery to do it, he said. About 80 million people in the United States are obese, but only 200,000 a year have bariatric operations. “There is a need for other therapies,” Dr. Kaplan said. “In no way is manipulating the microbiota going to mimic all the myriad effects of gastric bypass. But if this could produce 20 percent of the effects of surgery, it will still be valuable.” In people, microbial cells outnumber human ones, and the new studies reflect a growing awareness of the crucial role played by the trillions of bacteria and other microorganisms that live in their own ecosystem in the gut. Perturbations there can have profound and sometimes devastating effects. © 2013 The New York Times Company

Keyword: Obesity
Link ID: 17959 - Posted: 03.28.2013

Alternating between periods of eating and fasting is gaining in popularity among dieters and generating criticism in nutritional circles. Intermittent fasting, sometimes known as the 5:2 diet, asks people to eat very little or nothing at times, such as eating normally for five days a week and fasting for the other two. Brad Pilon designed one of the first intermittent fasts that became popular after he published a guide, Eat Stop Eat. Pilon said the diet allows followers to eat the foods they crave most of the time and still lose weight. "In the fasted state your body's set up to burn the calories you stored while eating," said Pilon. "So it's set up specifically for the act of burning body fat." Cutting down on weekly calorie intake is generally recommended. And there's research underway into the hypothesis that restricting calories could extend a healthy lifespan. Critics of intermittent fasting say that besides burning unwanted fat, the body will also burn its building blocks. "So when those energy stores start to drop the body looks for other sources and it goes to the muscles and burns muscle," said Margaret De Melo, a registered dietician at Toronto Western Hospital. © CBC 2013

Keyword: Obesity
Link ID: 17954 - Posted: 03.27.2013

By Sandra G. Boodman, A year after her daughter’s stomach problems began, Margaret Kaplow began having pains of her own. When she sat down to dinner with her family, Kaplow’s gut would clench involuntarily as she waited to see if this was one of the nights Madeline would eat a few bites before putting down her fork, pushing away from the table and announcing, “I don’t feel good.” For nearly six years, Maddie Kaplow’s severe, recurrent abdominal pain, which began shortly before her 13th birthday, was attributed to a host of ailments. Specialists in the District, Maryland and Virginia decided at various times that she had a gluten intolerance, a ruptured ovarian cyst, a diseased appendix or irritable bowel syndrome (IBS). Some were convinced that her problem was psychological and that she was a high-strung teenaged girl seeking attention. “It was a freaking nightmare,” Kaplow recalled of those years. She said she never believed her daughter was exaggerating or faking her symptoms. And each time a new diagnosis was made, Kaplow said, she felt elated that a doctor had figured out the cause of Maddie’s pain, which would turn into crushing disappointment when it recurred. It was only after she landed in a college infirmary 400 miles from her Northern Virginia home that doctors finally determined what was wrong and treated Maddie for the illness that dominated her adolescence. © 1996-2013 The Washington Post

Keyword: Pain & Touch
Link ID: 17948 - Posted: 03.26.2013

By TARA PARKER-POPE The best path to a healthy weight may be a good night’s sleep. For years researchers have known that adults who sleep less than five or six hours a night are at higher risk of being overweight. Among children, sleeping less than 10 hours a night is associated with weight gain. Now a fascinating new study suggests that the link may be even more insidious than previously thought. Losing just a few hours of sleep a few nights in a row can lead to almost immediate weight gain. Sleep researchers from the University of Colorado recruited 16 healthy men and women for a two-week experiment tracking sleep, metabolism and eating habits. Nothing was left to chance: the subjects stayed in a special room that allowed researchers to track their metabolism by measuring the amount of oxygen they used and carbon dioxide they produced. Every bite of food was recorded, and strict sleep schedules were imposed. The goal was to determine how inadequate sleep over just one week — similar to what might occur when students cram for exams or when office workers stay up late to meet a looming deadline — affects a person’s weight, behavior and physiology. During the first week of the study, half the people were allowed to sleep nine hours a night while the other half stayed up until about midnight and then could sleep up to five hours. Everyone was given unlimited access to food. In the second week, the nine-hour sleepers were then restricted to five hours of sleep a night, while the sleep-deprived participants were allowed an extra four hours. Copyright 2013 The New York Times Company

Keyword: Obesity; Aggression
Link ID: 17918 - Posted: 03.19.2013

By GINIA BELLAFANTE Under the category “Summer Rentals That Have Gone Terribly Wrong,” there are perhaps few parallels to the experience of Charles Henry Warren, a Manhattan banker who, in 1906, took a house in Oyster Bay on Long Island’s North Shore. By the end of the season, Mr. Warren’s young daughter had developed typhoid. She was soon followed in illness by Mr. Warren’s wife, a second daughter, two maids and a gardener. At the time, typhoid, a bacterial illness spread through contaminated food and water, was largely a disease of the urban poor. The property’s owner, George Thompson, concerned that the house, on which he relied for rental income, would become associated with tenement filth in the minds of wealthy New Yorkers, invited a sanitary engineer to determine the source of the outbreak. What the medical investigator, George Soper, discovered was that the Warrens’ cook, Mary Mallon, an Irish immigrant, had left an imprint of malady in other quarters of upper-class Manhattan and its summer enclaves. Typhoid, he wrote, had erupted in every household in which Mallon had worked over the previous decade. An asymptomatic carrier of the disease, Ms. Mallon would be known to history as Typhoid Mary and spend most of the remainder of her life quarantined on North Brother Island in the East River, having failed to abide by a promise to cease working in the city’s kitchens. The events supply the narrative of “Fever,” a new novel by Mary Beth Keane, which arrives at a time when we are once again debating the parameters of public health policy’s encroachments on our behaviors. Last week, a State Supreme Court justice in Manhattan used the words “arbitrary and capricious” in striking down the Bloomberg administration’s efforts to limit the size of sugary drinks (which pertained to certain sweetened beverages but not others, and some retail environments but not all). The phrase, though, could have been similarly applied a century ago to the city’s treatment of Ms. Mallon, given that officials were not in the habit of isolating other healthy carriers whom they had identified as ignoring ordinances against the spread of the disease. © 2013 The New York Times Company

Keyword: Obesity
Link ID: 17907 - Posted: 03.18.2013

By Meghan Rosen Alcohol may give heavy drinkers more than just a buzz. It can also fuel their brains, a new study suggests. Long-term booze use boosts brain levels of acetate, an energy-rich by-product of alcohol metabolism, researchers report online March 8 in the Journal of Clinical Investigation. In the study, people who downed at least eight drinks per week also sucked more energy from acetate than their light-drinking counterparts. The extra energy may give heavy drinkers more incentive to imbibe, says study coauthor Graeme Mason of Yale University. And the caloric perk might help explain why alcohol withdrawal is so hard. “I think it's a very good hypothesis,” says biochemical geneticist Ting-Kai Li of Duke University. Scientists had suspected that heavy drinkers absorb and burn more acetate, but, he adds, “Graeme Mason showed that this is actually happening.” Acetate is best known as a chemical in vinegar. But when people drink a glass of wine or drain a can of beer, their liver breaks down the alcohol and pumps out acetate as leftovers. The bloodstream then delivers acetate throughout the body, including to the brain. Human brains typically run on sugar. But with enough acetate in the blood, Mason thought, brains might crank up their ability to burn it too. To find out if his suspicion was correct, Mason and his colleagues peered into the brains of seven heavy drinkers and seven light drinkers, who quaffed fewer than two drinks per week. © Society for Science & the Public 2000 - 2013

Keyword: Drug Abuse
Link ID: 17887 - Posted: 03.11.2013

Surgically implanting pacemaker-like devices into the brains of people with severe anorexia might help improve their symptoms, a small Canadian study suggests. Anorexia affects an estimated 15,000 to 20,000 people in Canada, mainly young women who face a high risk of premature death. The mortality rate is between six to 11 per cent. About 60 to 70 per cent of people with anorexia recover fully with traditional treatments, said Dr. Blake Woodside, medical director of the eating disorders program at Toronto General Hospital. But in Wednesday's online issue of the medical journal The Lancet, Woodside and his co-authors describe using deep brain stimulation to treat six women with severe anorexia that did not respond to treatment. The treatment involves surgery to implant the electrical stimulators. It's considered minimally invasive and the stimulation can be turned off. In the pilot study, the average age of the women at diagnosis was 20 and they ranged in age from 24 to 57 when the surgery was performed. Five had a history of repeated hospital admissions for eating disorders. While the study was meant to test the safety of the procedure, not its effectiveness, Woodside's team found three of the six patients achieved and maintained a body mass index greater than their historical level. © CBC 2013

Keyword: Anorexia & Bulimia
Link ID: 17873 - Posted: 03.07.2013

By MICHAEL MOSS On the evening of April 8, 1999, a long line of Town Cars and taxis pulled up to the Minneapolis headquarters of Pillsbury and discharged 11 men who controlled America’s largest food companies. Nestlé was in attendance, as were Kraft and Nabisco, General Mills and Procter & Gamble, Coca-Cola and Mars. Rivals any other day, the C.E.O.’s and company presidents had come together for a rare, private meeting. On the agenda was one item: the emerging obesity epidemic and how to deal with it. While the atmosphere was cordial, the men assembled were hardly friends. Their stature was defined by their skill in fighting one another for what they called “stomach share” — the amount of digestive space that any one company’s brand can grab from the competition. James Behnke, a 55-year-old executive at Pillsbury, greeted the men as they arrived. He was anxious but also hopeful about the plan that he and a few other food-company executives had devised to engage the C.E.O.’s on America’s growing weight problem. “We were very concerned, and rightfully so, that obesity was becoming a major issue,” Behnke recalled. “People were starting to talk about sugar taxes, and there was a lot of pressure on food companies.” Getting the company chiefs in the same room to talk about anything, much less a sensitive issue like this, was a tricky business, so Behnke and his fellow organizers had scripted the meeting carefully, honing the message to its barest essentials. “C.E.O.’s in the food industry are typically not technical guys, and they’re uncomfortable going to meetings where technical people talk in technical terms about technical things,” Behnke said. “They don’t want to be embarrassed. They don’t want to make commitments. They want to maintain their aloofness and autonomy.” A chemist by training with a doctoral degree in food science, Behnke became Pillsbury’s chief technical officer in 1979 and was instrumental in creating a long line of hit products, including microwaveable popcorn. He deeply admired Pillsbury but in recent years had grown troubled by pictures of obese children suffering from diabetes and the earliest signs of hypertension and heart disease. In the months leading up to the C.E.O. meeting, he was engaged in conversation with a group of food-science experts who were painting an increasingly grim picture of the public’s ability to cope with the industry’s formulations — from the body’s fragile controls on overeating to the hidden power of some processed foods to make people feel hungrier still. It was time, he and a handful of others felt, to warn the C.E.O.’s that their companies may have gone too far in creating and marketing products that posed the greatest health concerns. © 2013 The New York Times Company

Keyword: Drug Abuse; Aggression
Link ID: 17843 - Posted: 02.25.2013

By Tina Hesman Saey Like the sun, insulin levels rise and fall in a daily rhythm. Disrupting that cycle may contribute to obesity and diabetes, a new study suggests. Many body systems follow a daily clock known as a circadian rhythm. Body temperature, blood pressure and the release of many hormones are on circadian timers. But until now, no one had shown that insulin — a hormone that helps control how the body uses sugars for energy — also has a daily cycle. Working with mice, researchers at Vanderbilt University in Nashville have found that rodents are more sensitive to insulin’s effects at certain times of day. Disrupting the animals’ circadian timers interferes with the hormone’s daily rise and fall and makes mice prone to obesity. If the findings hold up in humans, they could help explain why people who work night shifts tend to be overweight and suffer health problems. The discovery may also tie the obesity epidemic in part to staying up late and eating at the wrong time. Many people had thought that it was best for the body to maintain insulin at a relatively constant level, says Carl Johnson, a circadian biologist who led the new study. “But that’s not how organisms have adapted,” he says. Since the environment cycles through light and dark, body processes often coordinate with that rhythm. To uncover insulin’s natural rhythm, Johnson and his colleagues performed an “insulin clamp” procedure on mice. The clamp infuses glucose or insulin around the clock into mice that are moving freely in their cages. Measuring how much insulin or glucose the mice need to maintain constant blood sugar levels tells the researchers how responsive the animals are to the hormone at any given time of day. © Society for Science & the Public 2000 - 2013

Keyword: Biological Rhythms; Aggression
Link ID: 17831 - Posted: 02.23.2013

Diet pop and other artificially sweetened products may cause us to eat and drink even more calories and increase our risk for obesity and Type 2 diabetes, researchers are learning. Former McGill University researcher Dana Small specializes in the neuropsychology of flavour and feeding at Yale University in New Haven, Conn. Small said there's mounting evidence that artificial sweeteners have a couple of problematic effects. Sugar substitutes such as sucralose and aspartame are more intensely sweet than sugar and may rewire taste receptors so less sweet, healthier foods aren't as enjoyable, shifting preferences to higher calorie, sweeter foods, she said. Small and some other researchers believe artificial sweeteners interfere with brain chemistry and hormones that regulate appetite and satiety. For millennia, sweet taste signalled the arrival of calories. But that's no longer the case with artificial sweeteners. "The sweet taste is no longer signalling energy and so the body adapts," Small said in an interview with CBC News. "It's no longer going to release insulin when it senses sweet because sweet now is not such a good predictor of the arrival of energy." Susan Swithers, a psychology professor at Purdue University in West Lafayette, Ind., studies behavioural neuroscience. "Exposure to high-intensity sweeteners could change the way that sweet tastes are processed," she says. © CBC 2013

Keyword: Obesity; Aggression
Link ID: 17825 - Posted: 02.19.2013

By Jason Bittel Bears hibernate. They spend all year eating salmon, blueberries, and picnic baskets and then, sometime around baseball playoffs, they all wander off to a cave full of treasure and explorers’ skulls where they curl up in a big furry ball and snore away the winter. Everybody knows this! Even small children too young to attend to their own biological functions know how these wild animals make it through a period of harsh weather and food shortage. But beyond the fact that bears den up in winter, what do we really know of these lumbering slumber beasts and the secrets they keep beneath the ice and snow? Let’s start with this bit of housekeeping—cursory Googling of bears and hibernation will lead you to all sorts of trash talk saying bears aren’t “true hibernators.” True hibernators, such as Arctic ground squirrels, are capable of dropping their body temperatures below the freezing point of water, conditions so cold that neurons in the brain’s cortex are physically incapable of firing. Not to mention you can do all sorts of awful things to true hibernators while they slumber—like, oh, I don’t know, locking marmots in airtight jars filled with carbonic acid and hydrogen. (Easy, PETA. We’re talking 1832.) I know what you’re thinking: First Lance Armstrong, then Manti Te’o, and now this. But before you sit the kids down and blow their fragile little minds with the message that bears may not be true hibernators, consider that science is something of a moving target. The more we learn, the more questions we raise. © 2013 The Slate Group, LLC

Keyword: Miscellaneous
Link ID: 17812 - Posted: 02.18.2013

By SARAH LYALL IPSWICH, England — Who knows what the worst moment was for Paul Mason — there were so many awful milestones, as he grew fatter and fatter — but a good bet might be when he became too vast to leave his room. To get him to the hospital for a hernia operation, the local fire department had to knock down a wall and extricate him with a forklift. That was nearly a decade ago, when Mr. Mason weighed about 980 pounds, and the spectacle made him the object of fascinated horror, a freak-show exhibit. The British news media, which likes a superlative, appointed him “the world’s fattest man.” Now the narrative has shifted to one of redemption and second chances. Since a gastric bypass operation in 2010, Mr. Mason, 52 years old and 6-foot-4, has lost nearly two-thirds of his body weight, putting him at about 336 pounds — still obese, but within the realm of plausibility. He is talking about starting a jewelry business. “My meals are a lot different now than they used to be,” Mr. Mason said during a recent interview in his one-story apartment in a cheerful public housing complex here. For one thing, he no longer eats around the clock. “Food is a necessity, but now I don’t let it control my life anymore,” he said. But the road to a new life is uphill and paved with sharp objects. When he answered the door, Mr. Mason did not walk; he glided in an electric wheelchair. And though Mr. Mason looks perfectly normal from the chest up, horrible vestiges of his past stick to him, literally, in the form of a huge mass of loose skin choking him like a straitjacket. Folds and folds of it encircle his torso and sit on his lap, like an unwanted package someone has set there; more folds encase his legs. All told, he reckons, the excess weighs more than 100 pounds. © 2013 The New York Times Company

Keyword: Obesity
Link ID: 17772 - Posted: 02.06.2013

By Nathan Seppa The link between obesity and vitamin D deficiency appears to be a one-way street. A large study of the genetics underpinning both conditions finds that obesity may drive down vitamin D levels, but a predisposition to the vitamin deficiency doesn’t lead to obesity. The findings also suggest that boosting vitamin D levels won’t reverse obesity. An association between the two has been observed for years, but determining cause and effect has been difficult. “I find this very plausible and a correct interpretation of the data,” says Robert Heaney, an endocrinologist at Creighton University in Omaha, Neb. “I think it’s worth reporting.” In the new study, researchers tapped into a huge international database, accessing the genetic profiles of more than 42,000 people. The scientists noted whether a person harbored any of 12 genetic variants associated with being overweight. Not surprisingly, people with these variants were more likely to be obese than those without them. People with these obesity-associated gene variants were also apt to have low vitamin D levels, Elina Hyppönen, an epidemiologist and nutritionist at University College London, and colleagues report online February 5 in PLOS Medicine. When the researchers tested for four genetic variants linked to low vitamin D levels, they found that people with the variants were not necessarily prone to obesity. The researchers checked both findings against a separate database of people and got similar results. © Society for Science & the Public 2000 - 2013

Keyword: Obesity
Link ID: 17767 - Posted: 02.06.2013

by Michael Balter CAMBRIDGE, UNITED KINGDOM—Siberia may not be everyone's idea of a tourist destination, but it has been home to humans for tens of thousands of years. Now a new study of indigenous Siberian peoples presented here earlier this month at a meeting on human evolution reveals how natural selection helped people adapt to the frigid north. The findings also show that different living populations adapted in somewhat different ways. Siberia occupies nearly 10% of Earth's land mass, but today it's home to only about 0.5% of the world's population. This is perhaps not surprising, since January temperatures average as low as -25°C. Geneticists have sampled only a few of the region's nearly one dozen indigenous groups; some, such as the 2000-member Teleuts, descendants of a once powerful group of horse and cattle breeders also known for their skill in making leather goods, are in danger of disappearing. Previous research on cold adaptation included two Siberian populations and implicated a couple of related genes. For example, genes called UCP1 and UCP3 tend to be found in more active forms in populations that live in colder climes, according to work published in 2010 by University of Chicago geneticist Anna Di Rienzo and her colleagues. These genes help the body's fat stores directly produce heat rather than producing chemical energy for muscle movements or brain functions, a process called "nonshivering thermogenesis." The new study sampled Siberians much more intensely, including 10 groups that represent nearly all of the region's native populations. © 2010 American Association for the Advancement of Science

Keyword: Genes & Behavior; Aggression
Link ID: 17730 - Posted: 01.29.2013

When you eat could play an important role in weight loss, a new study suggests. Researchers looked at the role of meal timing in 420 men and women in southeast Spain participating in a 20-week weight-loss treatment following several studies in animals showing a relationship between the timing of feeding and weight regulation. Lunch was the main meal among the Mediterranean population studied.Lunch was the main meal among the Mediterranean population studied. (Eric Gaillard/Reuters) "Our results indicate that late eaters displayed a slower weight-loss rate and lost significantly less weight than early eaters, suggesting that the timing of large meals could be an important factor in a weight loss program," Frank Scheer, director of the medical chronobiology program at Brigham and Women's Hospital in Boston, said in a release. Of the participants, 51 per cent were early eaters who ate their main meal, lunch, before 3 p.m. The other 49 per cent had lunch after three. The researchers found energy and nutrient intake, estimates of calories burned, appetite hormones and hours of sleep were similar between both groups. "Nevertheless, late eaters were more evening types, had less energetic breakfasts and skipped breakfast more frequently than early eaters," Scheer and his co-authors wrote in Tuesday's issue of the International Journal of Obesity. They suggested that new weight loss strategies should incorporate the timing of food as well as the classic look at calorie intake and distribution of carbohydrates, fats and protein. © CBC 2013

Keyword: Obesity; Aggression
Link ID: 17728 - Posted: 01.29.2013

by Sara Reardon In the Arctic winter, it is not even worth getting up in the morning. It's freezing cold and the sun never rises, making it impossible to tell night from day. So each autumn, when the Arctic ground squirrel (Spermophilus parryii) heads underground to hibernate for eight months, it doesn't even bother setting its circadian clock. During hibernation, the squirrel goes into a state akin to suspended animation. It cuts itself off from the world and allows its body temperature to drop to -3 °C while it sleeps – the lowest ever body temperature recorded in a mammal. Once it wakes up for the summer, however, the squirrel can switch its daily clock back on. The squirrels' sub-zero tolerance was first discovered almost 25 years ago. Curious how the animals manage to survive the frigid Arctic winter where temperatures regularly drop to -30 °C, Brian Barnes of the University of Alaska in Fairbanks implanted radio transmitters into the stomachs of captive squirrels, which transmitted information on their body temperature, before letting them build burrows for the winter. Once the squirrels went into their deep sleep, Barnes found that their core body temperature dropped from about 36 °C to -3 °C. To prevent their blood from freezing, the squirrels cleanse it of any particles that water molecules could form ice crystals around. This allows the blood to remain liquid below zero, a phenomenon known as supercooling. © Copyright Reed Business Information Ltd.

Keyword: Miscellaneous
Link ID: 17715 - Posted: 01.26.2013

Experts are questioning whether diet drinks could raise depression risk, after a large study has found a link. The US research in more than 250,000 people found depression was more common among frequent consumers of artificially sweetened beverages. The work, which will be presented at the American Academy of Neurology's annual meeting, did not look at the cause for this link. Drinking coffee was linked with a lower risk of depression. People who drank four cups a day were 10% less likely to be diagnosed with depression during the 10-year study period than those who drank no coffee. But those who drank four cans or glasses of diet fizzy drinks or artificially sweetened juice a day increased their risk of depression by about a third. Lead researcher Dr Honglei Chen, of the National Institutes of Health in North Carolina, said: "Our research suggests that cutting out or down on sweetened diet drinks or replacing them with unsweetened coffee may naturally help lower your depression risk." But he said more studies were needed to explore this. BBC © 2013

Keyword: Depression; Aggression
Link ID: 17676 - Posted: 01.12.2013