Health Canada has issued a warning about serious skin and allergic reactions related to Alertec, a drug used to relieve excessive sleepiness due to narcolepsy, obstructive sleep apnea and shift-work sleep disorders. The federal agency said patients taking Alertec (modafinil) should seek immediate medical attention if they have any of the following symptoms: skin rash, hives, sores in the mouth, blisters and skin peeling; swelling of the face, eyes, lips, tongue or throat; trouble swallowing or breathing; or a hoarse voice. Alertec, made by Shire Canada Inc., is not approved in Canada for use in children for any condition. The drug can cause mental problems, such as depression, anxiety, hallucinations, mania and suicidal thoughts, although these events were rare during controlled studies. Health Canada says anyone experiencing such psychiatric conditions should stop taking Alertec and seek medical attention. Those taking the drug should tell their doctor if they have any heart problems, chest pain, have had a heart attack or a history of psychiatric disorders. © The Canadian Press, 2007

Keyword: Narcolepsy; Sleep
Link ID: 11130 - Posted: 06.24.2010

Brian Vastag About half of all depressed people who take standard antidepressant drugs fail to improve. Some suffer unpleasant side effects and abandon the medicines, while others simply don't feel better. Commercial tests claim to predict, by a genetic analysis, how well individual patients will fare on different antidepressants, but a panel convened by the Centers for Disease Control and Prevention (CDC) in Atlanta now says that the tests don't work as advertised. The panel "discourages" use of such tests until further studies clarify their value, according to a statement the group published in the December Genetics in Medicine. "That isn't to say that eventually there won't be a role for these tests. We just don't know what that role is yet," says panel member Joan Scott of the Genetics and Public Policy Center in Washington, D.C. The tests scan a person's DNA for variations in genes for two key liver enzymes. These enzymes break down selective serotonin reuptake inhibitors (SSRIs), a standard class of antidepressants that includes fluoxetine (Prozac) and nearly a dozen other drugs. Variations in the two enzymes affect how quickly different people clear SSRIs from their blood, which in turn influences the drugs' effectiveness. ©2007 Science Service

Keyword: Depression; Genes & Behavior
Link ID: 11129 - Posted: 06.24.2010

(HealthDay News) -- Developmental problems involving a walnut-shaped part of the brain called the amygdala -- linked to fear, anxiety and other emotions -- may explain why mental illness and addiction often appear together, researchers say. Many kinds of addiction -- such as those for alcohol, drugs and nicotine -- occur in people with various kinds of mental illness, including depression, schizophrenia and anxiety disorders, according to background information in an American Psychological Association news release about the Indiana University study. Two to five of every 10 anxious or depressed people, and four to eight of every 10 people with schizophrenia, biopolar disorder or antisocial personality, also have some form of addiction, according to epidemiological data. In this study, published in the December issue of Behavioral Neuroscience, the researchers compared the behavior of adult rats whose amygdalas were surgically damaged in infancy and adult rats with intact amygdalas. Rats with the damaged amygdalas showed less fear and caution than normal and were significantly more sensitive to cocaine after just one exposure to the drug. Rats with damaged amygdalas that received repeated cocaine injections developed "even stronger expressions of the enduring changes in behavior -- suggesting an overall hypersensitivity to the addictive process," the researchers noted. © 2007 Forbes.com LLC™

Keyword: Drug Abuse; Schizophrenia
Link ID: 11128 - Posted: 06.24.2010

For people in their 60s, regular walking appears to lower the risk of dementia. The finding, published this week in the medical journal Neurology, is the latest study to show that exercise helps delay some of the worst ravages of aging for both the body and the mind. The recent research tracked the exercise habits of 749 men and women in Italy who were over age 65 and were in good health, with no indication of memory problems at the beginning of the study. After four years, they found that the most-frequent walkers had a 27 percent lower risk for developing vascular dementia than those people who walked the least. What’s important about the study is that it again shows exercise doesn’t have to be excruciating to reap the benefits. “It’s important to note that an easy-to-perform moderate activity like walking provided the same cognitive benefits as other, more demanding activities,” said study author Dr. Giovanni Ravaglia of University Hospital S. Orsola Malpighi, in Bologna, Italy. Last year, the Annals of Internal Medicine reported on a study of more than 1,700 adults over 65 that also showed regular walkers have lower dementia risk. In that study, walkers who exercised three or more times a week showed a dementia risk of 13 per 1,000 person years, but the adults who walked less often had a risk of 19.7 per 1,000 person years. That translates to a nearly 40 percent reduction in risk. Copyright 2007 The New York Times Company

Keyword: Alzheimers
Link ID: 11127 - Posted: 06.24.2010

Men are naturally more comedic than women because of the male hormone testosterone, an expert claims. Men make more gags than women and their jokes tend to be more aggressive, Professor Sam Shuster, of Norfolk and Norwich University Hospital, says. The unicycling doctor observed how the genders reacted to his "amusing" hobby. Women tended to make encouraging, praising comments, while men jeered. The most aggressive were young men, he told the British Medical Journal. Previous findings have suggested women and men differ in how they use and appreciate humour. Women tend to tell fewer jokes than men and male comedians outnumber female ones. Research suggests men are more likely to use humour aggressively by making others the butt of the joke. And aggression - generally considered to be a more masculine trait - has been linked by some to testosterone exposure in the womb. Professor Shuster believes humour develops from aggression caused by male hormones. He documented the reaction of over 400 individuals to his unicycling antics through the streets of Newcastle upon Tyne. Almost half of people responded verbally - more being men. Very few of the women made comic or snide remarks, while 75% of the men attempted comedy - mostly shouting out "Lost your wheel?", for example. (C)BBC

Keyword: Hormones & Behavior; Emotions
Link ID: 11126 - Posted: 12.21.2007

CHICAGO - Children who have long, frequent or aggressive temper tantrums may be at risk of depression or disruptive disorders, U.S. researchers said on Thursday. They said tantrums were often the sign of a sick, hungry or overstimulated child. For most parents, they were a normal part of development and should be viewed as a teaching opportunity. But parents of children who hurt themselves or others and those who cannot calm themselves without help should seek medical help, they found. Healthy children tended to have less aggressive, and generally shorter tantrums. “I think parents to some degree should expect their children to have tantrums,” said Dr. Andy Belden of Washington University School of Medicine in St. Louis, whose study appeared in the Journal of Pediatrics. “If they are having extreme tantrums consistently. If almost every time they are having a tantrum they are hurting themselves or other people, that is a valid reason to go and talk to your pediatrician,” Belden said in a telephone interview. Copyright 2007 Reuters

Keyword: Development of the Brain; Depression
Link ID: 11125 - Posted: 06.24.2010

By Nikhil Swaminathan A new discovery about the function of neurons could help scientists understand how the brain assembles information during learning and memory formation. Scientists have found that when electrical impulses are passed from one neuron to another, they not only strengthen the synapse (connection) between them, but they also give a boost to neighboring synapses, priming them to learn more quickly and easily. Researchers report in Nature that the extra kick, which lasts from five to 10 minutes, may be key to memory formation. The residual effect "had been predicted based on so-called classic models of plasticity"—the ability of the brain to adapt by strengthening or weakening connections between neurons—but had not previously been proved, says study co-author Karel Svoboda, a biophysics group leader at the Howard Hughes Medical Institute's Janelia Farm Research Campus in Ashburn, Va. "You'd like to have clustered plasticity of this sort" to keep memories grouped together. Neurons, or nerve cells, each have a pair of projections—the axon and the dendrite, which transmit and receive impulses, respectively. The dendrite, a treelike structure, has several branches dotted with hundreds synaptic receiving terminals called "spines," each connected to the axons of scores of other neurons. When one of these spines receives stimulation (through the synapse it creates with another cell's axonal projection), the spine expands into the synapse, strengthening the link between its neuron and the other cell. This process of enhanced communication through a synapse is called long-term potentiation (LTP) and is thought to be the basis of learning. © 1996-2007 Scientific American Inc.

Keyword: Learning & Memory
Link ID: 11124 - Posted: 06.24.2010

Matt Kaplan Birds that sing in harmonious duets with one another have always been considered monogamous partners, with the singing thought to help in building faithful relationships. Now, research has shown at least that one such species sleeps around. Lauryn Benedict of the Museum of Vertebrate Zoology at the University of California, Berkeley, studied duetting California towhees (Pipilo crissalis ). She found that although female birds sang with the same male every day, more than one-quarter of their chicks were not fathered by her ‘husband’. “I’ve never caught a female in the act of cheating, they’re very secretive about their trysts,” says Benedict. But the duetting pairs copulate regularly together, she says. Ornithologists "perceived the beautiful harmonies of these birds as creating a sense of fidelity, but I suspected we were missing something”, says Daniel Mennill of the University of Windsor in Ontario. It’s uncertain whether the males in the pairs are also cheating, or how they would react if they caught their partner sneaking around. In the reed bunting (Emberiza schoeniclus ) and a few other bird species, the male feeds the young less often if it suspects the female of cheating, presumably because he knows the kids might not be his, says Benedict. © 2007 Nature Publishing Group

Keyword: Sexual Behavior; Language
Link ID: 11123 - Posted: 06.24.2010

Women with severe premenstrual syndrome (PMS) may have a permanently depressed nervous system, research suggests. A Japanese team found that PMS was tied to decreased activity in the autonomic nervous system - which controls the body's equilibrium - each month. The effect was most pronounced in women with the most severe, and potentially debilitating, PMS symptoms. The study, by Osaka's International Buddhist University, appears in the journal BioPsychoSocial Medicine. For some women PMS is a minor monthly annoyance, but for others, more severe symptoms seriously disrupt their lives. It is known that the condition is linked to hyper-sensitivity to the hormone progesterone, which is released by the body after ovulation. However despite the number of women affected, science has yet to offer a full explanation or universal treatment. The Japanese team measured heart rate variability and hormone levels in 62 women, and also used questionnaires to evaluate physical, emotional and behavioural symptoms. They found that women troubled by PMS showed decreased nervous activity in the late luteal phase, which precedes menstruation. Those with the most marked symptoms - known as premenstrual dysphoric disorder (PMDD) - had lower rates of nerve activity than the other groups during the entire menstrual cycle. Researcher Dr Tamaki Matsumoto said the underlying biological mechanism of PMS remained unclear. (C)BBC

Keyword: Hormones & Behavior
Link ID: 11122 - Posted: 12.20.2007

Brendan Maher Researchers have reversed almost all symptoms of fragile-X syndrome in a mouse model for the disease. In humans, fragile X is the most common form of heritable mental retardation and one of the leading known causes of autism. The findings, published today in Neuron, add to evidence suggesting a cause of fragile X defects — with possible therapeutic implications. Mouse studies could translate to help for humans with Fragile X.Getty“I think it’s an exciting set of findings that indicates a clear route to attempt treatment for a significant set of fragile-X symptoms,” says Thomas Jongens, a neurogeneticist at the University of Pennsylvania School of Medicine in Philadelphia, who was not involved in the research. Male mice have only one copy of the gene that encodes the fragile-X mutant related protein FMRP, which is — as its name suggests — mutated in the disease. When this gene is knocked out, the males produce a useful, if imperfect, model for the human disease. A team led by Mark Bear, director of the Picower Institute for Learning and Memory at the Massachusetts Institute of Technology in Cambridge, crossed these mice with other mice lacking a copy of a specific receptor protein called mGluR5. Earlier work had suggested that overproduction of mGluR5 could be responsible for fragile X defects. © 2007 Nature Publishing Group

Keyword: Development of the Brain; Genes & Behavior
Link ID: 11121 - Posted: 06.24.2010

Jennifer Viegas, -- People aren't the only primates who will pay for sex, new research shows. Male longtailed macaques exchange grooming for the right to mate with females whose fur they cleaned. The findings, which have been accepted for publication in the journal Animal Behavior, present the first evidence that a "social market" influences sexual interaction in a non-human primate. "I found that the amount of grooming a male performs on a female during a sexual interaction is related to the supply/demand ratio of females per male around the male-female pair at the time of the grooming," explained Michael Gumert, who conducted the research. Put another way, male monkeys -- especially lower status ones -- have to groom more to get more action when fewer females are around. Grooming in macaques involves using the teeth and hands to pick through the fur of the recipient to remove dirt, tangles and parasites. The activity often sexually excites the monkeys, particularly the males, so many scientists suspect it evolved into foreplay in humans. © 2007 Discovery Communications, LLC

Keyword: Sexual Behavior
Link ID: 11120 - Posted: 06.24.2010

Heidi Ledford Stimulating just one neuron can be enough to affect learning and behaviour, researchers have found. The results, published this week by Nature, conflict with the long-held notion that many neurons — in the order of thousands — are required to generate a behavioural reaction. The findings lend support to the ‘sparse-coding’ hypothesis of neural networks, which suggests that only a few neurons need to fire to generate a response. That theory has been hotly debated, says Karel Svoboda, a neurobiologist at the Janelia Farm research campus at Howard Hughes Medical Institute in Ashburn, Virginia, and one of the study's authors. “There are lots of fights about whether or not neural codes are sparse,” he says. Svoboda and his colleagues, as well as an independent group of researchers lead by Michael Brecht of the Humboldt University in Berlin, Germany, tackled the debate by studying the region in the rodent brain that receives sensory inputs from the whiskers. That region, called the barrel cortex, is made up of roughly two million neurons. Each whisker transmits signals to a group of cells clustered in the barrel-shaped arrangement that gives the region its name. © 2007 Nature Publishing Group

Keyword: Pain & Touch; Development of the Brain
Link ID: 11119 - Posted: 06.24.2010

CHICAGO - Nerves that sense the icy slap of an arctic wind or just a cool breeze take their orders from a single protein, U.S. researchers said on Monday, shedding new light on how we experience cold. Prior studies have suggested cold-sensing neurons are specialized, with some detecting painful cold sensations and others detecting more pleasant ones. But researchers at the University of Southern California have found that even though most cold-sensing neurons make use of a single protein known as TRPM8, they can detect a range of sensations. “We all know when we stimulate our teeth with cold we get this distinct cold sensation,” said David McKemy, whose study appears in the Journal of Neuroscience. “You get this sharp transient shooting pain and this dulled, aching sensation,” McKemy said in a telephone interview. Other groups have attributed that to two different cold sensory neurons. “There was a notion that there were neurons called cool fibers and there were others involved in detecting cold pain,” he said. He said he had expected neurons that express, or produce, TRPM8 to be of the pleasant cool variety. Copyright 2007 Reuters

Keyword: Pain & Touch
Link ID: 11118 - Posted: 06.24.2010

Inhaled cannabis smoke has more harmful toxins than tobacco, scientists have discovered. The Canadian government research found 20 times as much ammonia, a chemical linked to cancer, New Scientist said. The Health Canada team also found five times as much hydrogen cyanide and nitrogen oxides, which are linked to heart and lung damage respectively. But tobacco smoke contained more of a toxin linked to infertility. Experts said users must be aware of the risks. About a quarter of the population in the UK smokes tobacco products, while a sixth of 15 to 34-year-olds have tried cannabis in the past year, making it the most commonly used drug. Previous research has shown cannabis smoke is more harmful to lungs than tobacco as it is inhaled more deeply and held in the lungs for a longer period. However, it has also been acknowledged that the average tobacco user smokes more than a cannabis user. Researchers from Health Canada, the government's health research department, used a smoking machine to analyse the composition of the inhaled smoke for nearly 20 harmful chemicals. They also looked at the sidestream smoke, given off from the burning tip of the product and responsible for 85% of the smoked inhaled through passive smoking. In most cases, the comparison on sidestream smoke broadly mirrored that of inhaled smoke. However, in the case of polycyclic aromatic hydrocarbons, the toxin linked to infertility, the researchers found concentrations were actually higher in cigarette smoke. The study also showed little difference in the concentrations of a range of chemicals, including chromium, nickel, arsenic and selenium. (C)BBC

Keyword: Drug Abuse
Link ID: 11117 - Posted: 12.19.2007

Scientists have figured out why your skin tenses up and your teeth chatter when an icy blast of wintry wind whips past: The brain’s wiring system monitors the temperature of the skin and decides when the shivering should commence. Shivering is one of the many automatic and subconscious functions that the body performs to regulate itself. Other so-called homeostatic functions include the adjustment of breathing rates, blood pressure, heart rate and weight regulation. Shivering is essentially the body's last-ditch effort to keep itself warm. "Shivering, which is actually heat production in skeletal muscles, requires quite a bit of energy and is usually the last strategy the body uses to maintain its internal temperature to survive in a severe cold environment," said Oregon Health & Science University research fellow Kazuhiro Nakamura. Nakamura and his colleagues studied rats and traced the shivering sensory pathway from the rodents' skin to specialized cells in a portion of the brain called the lateral parabrachial nucleus. These cells can then transmit information to another part of the brain, the preoptic area, which decides when the body should start shivering. © 2007 LiveScience.com

Keyword: Miscellaneous
Link ID: 11116 - Posted: 06.24.2010

Jennifer Viegas, Discovery News -- Treatments for depression range from medicines that can come with scary side effects to electric shock therapy, but a new paper suggests a simple cold shower might sometimes cure, and even prevent, the debilitating mood disorder. Cleanliness may be a pleasant side effect, but the key lies in the water temperature. The study's author, Nikolai Shevchuk, believes the biological explanation revolves around a part of the brainstem known, appropriately enough, as the locus ceruleus, or "blue spot." Shevchuk, who formulated the theory while working in the Department of Radiation Oncology at Virginia Commonwealth University School of Medicine, told Discovery News that short, cold showers may stimulate the blue spot, which is the brain's primary source of noradrenaline -- a chemical that could help mediate depression. "The possible antidepressant effect may also have to do with the mild electroshock delivered to the brain by a cold shower, because of the unusually high density of cold receptors in the skin," he added, explaining that these nerve endings are 3-10 times higher in density than those registering warmth. © 2007 Discovery Communications, LLC.

Keyword: Depression
Link ID: 11115 - Posted: 06.24.2010

Heidi Ledford Animals need to get oxygen to their brain during long dives.ALAMYMarine mammals have an uncanny ability to remain awake and alert while holding their breath during long dives. New research shows that this might be thanks to high concentrations of oxygen-binding proteins in the brain. The proteins, called globins, could help these mammals to remain active long after blood oxygen levels sink low enough to cause a human to black out. Some marine mammals can spend more than 90 minutes under water, altering their physiology to make the most of their limited oxygen supply. Their heartbeats slow down, and blood flow is prioritized to the brain by mobilizing oxygen stores in muscles and constricting blood vessels leading to peripheral tissues. They can also suppress their shivering instinct in cold waters, allowing their body temperature to drop, again conserving oxygen (see Seals don't shiver in chilly waters). These changes are similar to those seen in hibernation, leading some to speculate that diving mammals enter a sort of torpor. But Terrie Williams, a marine-mammal physiologist at the University of California at Santa Cruz, has observed mammals during their dives and knows that they often remain active. "They’re alert, their eyes are moving around watching you," says Williams. "These are not animals that appear to be asleep or hibernating. They’re on top of their game." © 2007 Nature Publishing Group

Keyword: Stroke
Link ID: 11114 - Posted: 06.24.2010

CHICAGO - A mutation in a single gene may raise one's risk of developing amyotrophic lateral sclerosis (ALS), also know as Lou Gehrig's disease, by as much as 30 percent, offering a potential new target for drug research, Dutch scientists said on Sunday. They said a variant in the DPP6 gene may give rise to ALS in people without a family susceptibility to the untreatable and fatal disease. Familial ALS, which accounts for 10 percent of all cases of the disease, has been linked with mutations in a number of other genes. Researchers have had less luck finding a gene associated with non-familial, sporadic ALS, which accounts for 90 percent of ALS cases. But researchers at the University Medical Center Utrecht said a SNP or single-letter change in the genetic code of the DPP6 gene is "consistently and strongly associated with susceptibility to amyotrophic lateral sclerosis in different populations of European ancestry." The DPP6 gene controls an enzyme found mostly in the brain that has been linked with spinal cord injury in rats. (c) Reuters 2007.

Keyword: ALS-Lou Gehrig's Disease ; Genes & Behavior
Link ID: 11113 - Posted: 12.18.2007

By RICHARD A. FRIEDMAN, M.D. In a few days, the winter solstice will plunge us into the longest and darkest night of the year. Is it any surprise that we humans respond with a holiday season of relentless cheer and partying? It doesn’t work for everyone, though. As daylight wanes, millions begin to feel depressed, sluggish and socially withdrawn. They also tend to sleep more, eat more and have less sex. By spring or summer the symptoms abate, only to return the next autumn. Once regarded skeptically by the experts, seasonal affective disorder, SAD for short, is now well established. Epidemiological studies estimate that its prevalence in the adult population ranges from 1.4 percent (Florida) to 9.7 percent (New Hampshire). Researchers have noted a similarity between SAD symptoms and seasonal changes in other mammals, particularly those that sensibly pass the dark winter hibernating in a warm hole. Animals have brain circuits that sense day length and control the timing of seasonal behavior. Do humans do the same? In 2001, Dr. Thomas A. Wehr and Dr. Norman E. Rosenthal, psychiatrists at the National Institute of Mental Health, ran an intriguing experiment. They studied two patient groups for 24 hours in winter and summer, one group with seasonal depression and one without. Copyright 2007 The New York Times Company

Keyword: Depression; Biological Rhythms
Link ID: 11112 - Posted: 06.24.2010

Carl Zimmer, New York Times The word "big" doesn't do justice to whales. Humpback whales can weigh up to 40 tons. Fin whales have been known to reach 80 tons. Blue whales, the biggest animals to have ever lived, reach 160 tons - the same mass as about 2,000 grown men or 5 million grown mice. It takes a lot of food to build such giant bodies, but how exactly the biggest whales get so much has long been a mystery. "We don't have much of a sense of these animals in their natural environments," said Nick Pyenson, a biologist at UC Berkeley. For decades, whale experts had only indirect clues. "It's primarily from dead animals or from a few people standing on a ship seeing whales come to the surface," he said. With so little information, scientists have struggled to make sense of several enigmas about the biggest whales. "It's always been a mystery why they have really short dives for their body size," Pyenson said. The bigger a marine mammal is, the longer it should be able to dive for food, because it has more muscle tissue in which it can store oxygen. Other species follow this pattern, but the biggest whales do not. Pyenson and his colleagues may have solved some of the gastronomical mysteries of these leviathans by creating the first detailed biomechanical model of a feeding fin whale. In essence, they have created the world's biggest gulp. © 2007 Hearst Communications Inc.

Keyword: Obesity
Link ID: 11111 - Posted: 06.24.2010