By Sandi Doughton As the culture wars rage over gay rights, a flock of sheep at Oregon State University may help answer a key question behind the controversy: Is homosexuality a matter of choice or biology? The Corvallis herd includes a group of rams that scientists delicately refer to as "male-oriented." These animals consistently ignore females and bestow all their amorous attentions on members of their own sex. Researcher Charles Roselli says a decade of study suggests sexual orientation is largely hard-wired into the sheep's brains before birth. Now, he's trying to figure out how that happens, zeroing in on genes and hormones. In a bold test of his ideas, he hopes to engineer the birth of gay rams by altering conditions in the womb. Sheep aren't people, but the Oregon work adds to a growing body of research that bolsters biological explanations for sexual orientation across species — including humans. Despite those scientific findings, some religious groups say homosexuality is a lifestyle that can be treated, if not prevented. One such group, the conservative Christian organization Focus on the Family, is sponsoring a one-day conference in Bothell Saturday. The social and political implications of the research are impossible to ignore, leading to unease on both sides of the gay-rights debate. If science proves homosexuality is innate, is there any basis to deny gays equal treatment — including the right to marry? But if scientists unravel the roots of sexual orientation, will it some day be possible to "fix" people who don't fit the norms or abort fetuses likely to be born gay? Copyright © 2005 The Seattle Times Company

Keyword: Sexual Behavior
Link ID: 7517 - Posted: 06.24.2010

Men who are no good at wooing the ladies may be able to blame their genes, after researchers have made a discovery in the humble fruit fly. Manipulation of a single gene in male fruit flies made them less adept at courting female mates, a US and an Austrian team have both found. While humans do not possess this gene, we do share many with fruit flies. The research, in the journals Nature and Cell, suggested sexual behaviour has a strong biological basis. Others still argue that it is down to upbringing. Professor Barbara Taylor and colleagues at Oregon State University in the US and Dr Barry Dickson and colleagues at the Austrian Academy of Sciences looked at the 'fruitless' gene, which is present in both male and female fruit flies. Ordinarily, it is only in males that this gene results in the creation of proteins that guide male sexual behaviour patterns, such as approaching females, tapping and singing to them and performing courtship dances. When the researchers manipulated the male fruit flies so that they had a faulty fruitless gene the flies no longer showed typical male sex-related behaviours Conversely, when females had their genes manipulated so that they produced the male proteins, they began to show classic patterns of male sexual behaviour. Professor Taylor said: "In a physical sense, the females looked perfectly normal, but they acted like males and, if they were physically able to, I would not be surprised if they would have attempted to mate other females." "Research of this type is telling us quite a bit about they ways in which things we believe are developmental actually have a biological and genetic underpinning," she said. Co-author of the US study, which appears in Neuron, Dr Jeffrey Hall, said he would not be surprised to learn that human sexual behaviours also had similar mechanisms underpinning them. (C)BBC

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7516 - Posted: 06.17.2005

St. Paul, Minn. – A new study shows that the prognosis is good for people who have epilepsy surgery, even 30 years after the surgery. The study is published in the June 14 issue of Neurology, the scientific journal of the American Academy of Neurology. “Few studies have looked at the long-term prognosis for epilepsy surgery,” said neurologist and study author William H. Theodore, MD, of the National Institute of Neurological Disorders and Stroke in Bethesda, Md. “We found that 50 percent of the patients were free of seizures 30 years after the surgery.” In epilepsy, surgery is generally considered for those whose seizures do not respond to medication. The study involved people who had a temporal lobectomy, which is the surgical removal of the portion of the brain where seizures most often occur. The study examined 48 people who had a temporal lobectomy at the National Institutes of Health in Bethesda an average of nearly 30 years previously. The patients or their families were questioned about whether they had experienced seizures at one year after the surgery, and at five, 10, and 30 years after the surgery. At 30 years, 14 people were free of seizures and taking no epilepsy drugs; 10 people were free of seizures while taking epilepsy medication. Those who had seizures within the first year after surgery were least likely to be free of seizures in the future.

Keyword: Epilepsy
Link ID: 7515 - Posted: 06.24.2010

Immediate, large rewards cause animals to make fast, correct decisions. But the real world is fettered with choices that don't lead to timely, big bonuses--such as having to slog through cleaning our plate to get to dessert. A new study fingers a region of the brain called the thalamus, which may give us the motivation to eat the green beans of life so we can have our cheesecake. Scientists trying to understand the circuits in the brain that reward animals for making choices have long focused on two regions: the cortex, where the higher functions such as paying attention reside, and the basal ganglia, where the neurotransmitter dopamine acts to make the brain feel rewarded. A third region, the thalamus, connects to both areas, but neuroscientists have long thought that it functions mainly in relaying sensory information. Neuroscientist Minoru Kimura at the Kyoto Prefectural University of Medicine in Japan wondered if the thalamus might play a role in a decision-making that led to smaller, less immediate rewards. To find out, Kimura and colleagues hooked up two rhesus monkeys to electrodes that recorded signals coming from a specific part of the thalamus. Then the team had the monkeys hold down a lever until a button lit up as red or green. When the light was red, the animals were trained to let go of the lever and press the button. When they did this, they got a large amount of water--a big reward. But when the button shone green and the monkeys were trained to hold the lever down, they received significantly less water--a small reward. In addition, a less-compensated task was usually followed by a task that rewarded the big drink of water. The team found that the neurons in the thalamus stayed silent when the red light came on (i.e., when the monkeys anticipated a large reward) but flared when the green light came on (i.e., when the monkeys were resigned to a small reward). To see if the neurons controlled the animals' behavior, the researchers stimulated the nerve cells via implanted electrodes just as the button lit up. Even if the animal was supposed to perform the large reward task, stimulating the neurons caused them to perform the small reward task instead, the team reports 17 June in Science. Copyright © 2005 by the American Association for the Advancement of Science.

Keyword: Drug Abuse
Link ID: 7514 - Posted: 06.24.2010

Researchers have discovered that a set of light-responsive retinal cells that form connections to the circadian clock are functional very early in development, from the day of birth. Although the cells are sensitive to light, they do not participate in image formation, a process that matures later on. The work has been reported in the journal Current Biology by Sumathi Sekaran, of Imperial College London, and colleagues there and at John Hopkins University and the University of Manchester. The visual system is known to be composed of the classical image-forming pathway, which involves the function of rod and cone photoreceptors, as well as the more recently discovered non-image-forming pathway, which involves specialized neurons called intrinsically photoreceptive retinal ganglion cells (ipRGCs). Although extensive research has characterized the delayed functional maturation of rod and cone photoreception, information pertaining to the development of the ipRGCs has been lacking. It was known, however, that a photopigment present in mature ipRGCs, retinal melanopsin, is expressed long before the classical rod and cone photopigments. The new research directly studied the functional development of the ipRGCs in mice via a range of approaches, including the examination of melanopsin expression, the physiological recording of ganglion-cell light responses, and the measuring of functional outputs of these cells to higher brain regions. The researchers found that, quite remarkably, the melanopsin-expressing ganglion cells are present in abundance and act as functional photoreceptors from the day of birth, when it has been widely assumed the mouse retina lacks photodetection. At the time of birth, a significant percentage of cells in the retinal ganglion-cell layer express melanopsin and respond to light.

Keyword: Biological Rhythms; Vision
Link ID: 7513 - Posted: 06.17.2005

By Jennifer Viegas, Discovery News — Elephants not only converse with each other, but each possesses its own unique, expressive voice, according to a new study on African elephants at Disney's Animal Kingdom in Florida. The findings suggest elephants live rich social lives and feel an array of human-like emotions. The data also strengthen claims that animal communication can be content-rich and emotionally complex. While careful human listeners might hear elephant conversations, elephants, particularly chatty females, converse in low-pitched rumbles that often are missed by human ears, according to two related studies, which have been accepted for publication in the journal Animal Behavior. Similar to humans ignoring conversations at other tables in a restaurant, elephant strangers do not pay much attention to each other. "Female friends exchange rumbles even when they are out of sight from one another, and their voices differ from one another, so I believe that they can recognize each other by their voices alone, just as humans and many other social animals can do," said Joseph Soltis, who led the study. Copyright © 2005 Discovery Communications Inc.

Keyword: Animal Communication; Language
Link ID: 7512 - Posted: 06.24.2010

PITTSBURGH, – Despite an intensive effort, researchers have yet to identify the genes that cause bipolar disorder, yet the practical benefits of such a discovery could reap rich rewards for those suffering from the mental illness. New research findings presented today at the Sixth International Conference on Bipolar Disorder suggest specific genetic linkages that are associated with the mental illness, bringing researchers much closer to finding the elusive gene or genes. Another study finds an association between an abnormal thyroid condition and bipolar disorder, pointing to the possibility that a simple blood test could help identify those at risk. To further investigate more specific genetic linkages, Marion Leboyer, M.D., Ph.D., of the University of Paris Faculty of Medicine, studied 87 bipolar sibling pairs from 70 European families who were participants in the European Collaborative Study on Early Onset Bipolar Affective Disorder and identified eight regions of genetic linkages that, while not necessarily the sole or unique ones associated with this disease, zeroed in on what may be the specific genes that predispose individuals to early onset of this debilitating disease. According to Dr. Leboyer, his studies of families with members who developed the illness as children or adolescents reduces those genetic and clinical variabilities that can complicate efforts to identify susceptibility genes. Finding these genes would help researchers develop more effective treatments or even prevent the disorder from occurring in at-risk individuals.

Keyword: Schizophrenia; Genes & Behavior
Link ID: 7511 - Posted: 06.24.2010

Friends, not family, are the key to a longer life, a new study suggests. While previous research has found that strong social networks help older people live longer, the work had not distinguished between contact with friends or relatives. The new study followed almost 1500 Australians, initially aged over 70. Those who at the start reported regular close personal or phone contact with five or more friends were 22% less likely to die in the next decade than those who had reported fewer, more-distant friends. But the presence or absence of close ties with children or other relatives had no impact on survival. The reasons are not entirely clear. Friends and confidantes might help with coping in times of stress and difficulty, the team suggests. They might also encourage healthy behaviours, such as seeking help for new medical symptoms. Journal reference: Journal of Epidemiological and Community Health (vol 59, p 538) © Copyright Reed Business Information Ltd.

Keyword: Neuroimmunology
Link ID: 7510 - Posted: 06.24.2010

SAO PAULO, Brazil (Reuters) - Two Brazilian doctors and amateur art lovers believe they have uncovered a secret lesson on human anatomy hidden by Renaissance artist Michelangelo in the Sistine Chapel's ceiling. Completed nearly 500 years ago, the brightly colored frescoes painted on the Vatican's famous sanctuary are considered some of the world's greatest works of art. They depict Biblical scenes such as the "Creation of Adam" in which God reaches out to touch Adam's finger. But Gilson Barreto and Marcelo de Oliveira believe Michelangelo also scattered his detailed knowledge of internal anatomy across 34 of the ceiling's 38 panels. The way they see it, a tree trunk is not just a tree trunk, but also a bronchial tube. And a green bag in one scene is really a human heart. The key to finding the numerous organs, bones and other human insides is to first crack a "code" they believe was left behind by the Florentine artist. Essentially, it is a set of sometimes subtle, sometimes overt clues, like the way a figure is pointing. "Why wasn't this ever seen before? First, because very few people have the sufficient anatomical knowledge to see these pieces like this. I do because that's my profession," said Barreto, who is a surgeon in the Brazilian city of Campinas. Barreto and his friend Oliveira are not the first physicians to see depictions of human organs in the Sistine Chapel, the Vatican church where popes are elected. Fifteen years ago, U.S. doctor Frank Meshberger pointed out the figure of God and his surrounding angels in the "Creation of Adam" panel resembled a cross-section of the human brain. Copyright © 2005 Yahoo! Inc.

Keyword: Miscellaneous
Link ID: 7509 - Posted: 06.24.2010

By David Brown and Shailagh Murray Terri Schiavo suffered severe, irreversible brain damage that left that organ discolored and scarred, shriveled to half its normal size, and damaged in nearly all its regions, including the one responsible for vision, according to an autopsy report released yesterday. Although the meticulous postmortem examination could not determine the mental state of the Florida woman, who died March 31 after a judicial and legislative battle over her "right to die," it did establish the permanence of her physical condition. Schiavo's brain damage "was irreversible . . . no amount of treatment or rehabilitation would have reversed" it, said Jon R. Thogmartin, the pathologist in Florida's sixth judicial district who performed the autopsy and announced his findings at a news conference in Largo, Fla. Still unknown is what caused Schiavo, 41, to lose consciousness on a winter morning in 1990. Her heart beat ineffectively for nearly an hour, depriving her brain of blood flow and oxygen. A study of her organs, fluids, bones and cells, as well as voluminous medical records, failed to support strangulation, beatings, a drug overdose, complications of an eating disorder or a rare molecular heart defect. All had been offered as theories over the past 15 years. Thogmartin said the cause will probably never be known. © 2005 The Washington Post Company

Keyword: Miscellaneous
Link ID: 7508 - Posted: 06.24.2010

As any guy who's been dragged onto the dancefloor knows, getting the girl means sometimes you have to dance. In some species of fruit flies male sex appeal seems to boil down to how well he can dance, as well as how good he looks while he struts his stuff. But, since flies don't have fashion consultants, it's his genes that supply him with the showy black spots he displays on on the tips of his wings. "The species that have these spots have an elaborate courtship ritual where they dart out in front of the females and they extend their wings and do a little dance while they display these spots," says Sean Carroll, genetics professor at the University of Wisconsin-Madison and Howard Hughes Medical Institute. "It's quite clear that these spots are a visual cue that the females are picking up on in the selection of mates, and the success of mating of males being linked to their possession of this trait — that process is called sexual selection and it's a very powerful evolutionary force." Since fruit flies have long been the workhorses of genetics, Carroll and his colleagues used them to study how such traits evolve at the genetic level — to learn how genes change through evolution to produce such styles in the males of many species. "We see all sorts of coloration used in all sorts of biological roles, but attracting mates is the predominate one. Think of the spots of the peacock, think of the fancy feather color patterns of male birds," Carroll explains. © ScienCentral, 2000-2005.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7507 - Posted: 06.24.2010

Personality and talents are usually chalked up to a mysterious mix of heredity and environment. A provocative new study, however, hints at a third factor: bits of genetic material that spontaneously hop around the genome of neurons in the developing brain, altering patterns of gene expression. The scientists who discovered the phenomenon propose that it adds a random twist to neural development that ensures that no two brains--not even those of identical twins--are put together in exactly the same way. The researchers, led by Fred Gage at the Salk Institute for Biological Sciences in La Jolla, California, were investigating how neural stem cells decide whether to turn into neurons or support cells. Searching for genes that might guide this decision, the team noticed that rat cells in the process of becoming neurons contained increased levels of RNA corresponding to so-called L1 retrotransposons, bits of DNA that can jump around in the genome, sometimes altering the activity of genes they land in. Intrigued, the team inserted a human version of L1 into rat neural stem cells, along with a marker that would make the cells glow green whenever L1 made a jump. Many cells lit up, and when the researchers took a closer look, they found that L1 jumped into several genes typically expressed by neurons. In some cases, the jump altered gene expression in a way that influenced the stem cells' fate--making them more likely to turn into neurons, for example. Additional experiments with transgenic mice indicated that L1 had hopscotched in a subset of brain cells, but not in the cells of most other tissues. In principle, Gage says, this process could generate distinct neural circuitry in each individual by altering the proportion of neuron types or levels of gene expression in the brain. Copyright © 2005 by the American Association for the Advancement of Science.

Keyword: Development of the Brain; Genes & Behavior
Link ID: 7506 - Posted: 06.24.2010

In experiments with mice, researchers have found that nicotine triggers the same neural pathways that give opiates such as heroin their addictively rewarding properties--including associating an environment with the drug's reward. However, unlike opiates, nicotine does not directly activate the brain's opiate receptors, but activates the natural opioid reward pathway in the brain. The researchers, led by Julie Blendy of the Transdisciplinary Tobacco Use Research Center (TTURC) at the University of Pennsylvania, said their findings suggest more effective ways that opiate blockers could be used to help smokers quit. In their experiments reported in the June 16, 2005, issue of Neuron, the researchers administered nicotine to mice and analyzed the levels of a protein called CREB--known to control genes involved in the reward pathway of opiates and other abused drugs. They found that not only was CREB activated in the reward regions of the nicotine-treated animal's brains, but also that the drug naloxone, which blocks the opiate receptors, blocked CREB activation. Also, mutant mouse strains lacking the opioid receptor did not show an increase in CREB activity when they received nicotine. The researchers also studied the relationship among nicotine, the environment, and this reward pathway. They conditioned mice to associate a specific test chamber with receiving nicotine, finding that the mice would prefer to stay in that chamber when given a choice. The researchers found that just placing the conditioned mice in the chamber activated CREB. They also found that naloxone blocked this conditioned increase in CREB, and that mutant mice lacking CREB or pretreated with naloxone did not show any reward response to nicotine.

Keyword: Drug Abuse; Learning & Memory
Link ID: 7505 - Posted: 06.16.2005

Many of the medications widely used to manage chronic insomnia have not yet been rigorously evaluated for long-term use, according to an independent scientific panel convened this week by the National Institutes of Health. This is a critical consideration because for many patients, insomnia can persist for decades. The panel also stressed that many chronic insomnia sufferers could benefit from currently underused behavioral and cognitive therapies. The panel was concerned that many of the drugs now used to treat insomnia, such as antidepressants and antihistamines, have not been approved for this indication; their efficacy in treating chronic insomnia has not been proven. Even those medications that have been approved for insomnia are approved only for short-term use, leaving chronic sufferers with few proven options. The panel noted that newer benzodiazepine receptor agonist medications have been developed that have fewer and less severe adverse effects than other medications, and show promise for long-term use, but this requires further evaluation. The panel also expressed concern that many insomnia sufferers self-medicate with alcohol, despite the numerous risks involved and the clear evidence that alcohol actually has a negative overall effect on the quality of sleep. Research indicates that behavioral methods such as relaxation training can be effective to treat insomnia when combined with cognitive therapies specifically targeted at anxiety-producing beliefs and erroneous beliefs about sleep and sleep loss. Moreover, this approach is unlikely to carry adverse side effects, and its benefits may be longer lasting than pharmacological interventions. There are few practitioners trained in these therapies, however.

Keyword: Sleep
Link ID: 7504 - Posted: 06.16.2005

CORVALLIS, Ore. – New research has shown that the manipulation of a single gene in female fruit flies can make their sexual behavior resemble that of males, in a study that demonstrates the power of individual genes and the profound impact of genetics on complex sexual behavior. The findings were published today in the journal Nature by scientists from Oregon State University, Stanford University and Brandeis University. The research was done with the gene "fruitless," which is present in both male and female fruit flies and some other insect species. Ordinarily, only in males does this gene result in the creation of proteins that guide male sexual behavior patterns – such as approaching females, tapping them, singing to them and performing little courtship dances. However, through genetic manipulations the research group of university scientists was able to cause these same proteins to be produced in females, and when they were, the females showed classic patterns of male sexual behavior. "When this genetic process was triggered in females, they acted as if they were masculinized," said Barbara Taylor, a professor of zoology at OSU. "And this was a single gene expressed in just a very small number of cells, controlling a surprisingly complex behavior. In a physical sense the females looked perfectly normal, but they acted like males and, if they were physically able to, I would not be surprised if they would have attempted to mate other females."

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7503 - Posted: 06.24.2010

Mice that are briefly stressed out before receiving a vaccine develop a better immune response than mice under no psychological stress, a new study reveals. This advantageous immunity persists for at least nine months - a good chunk of a mouse lifespan - and is likely to arise because an acutely stressed immune system develops better memories for foreign invaders, the study’s authors suggest. “Stress can influence different features of the immune response in different ways, sometimes improving and sometimes suppressing” this response, says Monika Fleshner, of the University of Colorado at Boulder, US. While chronic stress suppresses “nearly every feature of the immune system,” acute stress can enhance some features, she says. Firdaus Dhabhar and Kavitha Viswanathan at Ohio State University, US, injected mice with a small amount of protein called keyhole limpet hemocyanin (KLH), which triggers the body’s immune response in a way similar to many proteins, according to Dhabhar. Half of the mice were put in small, unfamiliar wire cages for two and a half hours immediately before receiving their immunisations, while the other half stayed in their regular cages. Nine months later, the researchers injected the animals with KLH at a different skin site. Mice that had been confined before being immunised developed much more skin inflammation than did the non-stressed mice - a sign that their bodies’ immune systems responded more intensely to the new injections. The researchers show that many more immune cells rushed to the injection sites in mice that had been stressed. © Copyright Reed Business Information Ltd

Keyword: Neuroimmunology; Stress
Link ID: 7502 - Posted: 06.24.2010

Roxanne Khamsi A vaccine developed to fight brain disorders such as Parkinson's disease has shown promise in preliminary animal trials. But experts caution that the positive results may not translate into an effective treatment for humans. The formation of abnormal protein aggregates in the brain, known as Lewy bodies, has been linked to several neurological disorders in adults. These include Parkinson's disease, a condition that can involve slow movements, tremors and impaired coordination. Genes may predispose someone to the disease, say researchers. Others point to environmental toxins as a potential trigger. Whatever the cause, doctors currently lack a cure for Parkinson's disease and related Lewy-body illnesses. Many think that getting the immune system to attack the protein aggregates is a good step towards finding a treatment. So several research teams have been pursuing therapeutic vaccines. Biologists have already succeeded in giving mice specially designed immune cells to save them from neurological damage. Now they have gone a step further by getting mice to produce their own immune protection through a series of injections. The vaccine, developed by Leslie Crews of the University of California, San Diego, and colleagues, is based on the protein in Lewy bodies, known as alpha-synuclein. An overdose of this protein, which acts at the tips of nerve cells, apparently creates these aggregates in mice. Animals genetically engineered to overproduce the protein also exhibit Parkinsonian symptoms. ©2005 Nature Publishing Group

Keyword: Parkinsons
Link ID: 7501 - Posted: 06.24.2010

The Clock gene, widely appreciated as a driver of circadian rhythms, has now been shown to aid in regulating the brain's reward circuitry, which is triggered by drugs of addiction, such as cocaine. The findings from this study and others continue to build the case that Clock is a key cog in the machinery that drives an ever widening range of behaviors. The researchers, including Howard Hughes Medical Institute investigator Joseph S. Takahashi at Northwestern University, published their findings June 13, 2005, in the early online edition of the Proceedings of the National Academy of Sciences. Other co-authors include Eric J. Nestler and colleagues from the University of Texas Southwestern Medical Center, the University of Crete and the Rosalind Franklin University of Medicine and Science in Chicago. Studies by Takahashi and other researchers have revealed that Clock regulates other genes involved in the biological clock machinery. Most biological clocks operate on a 24-hour, circadian (Latin for "about a day") cycle that governs functions such as sleeping and waking, rest and activity, fluid balance, body temperature, cardiac output, oxygen consumption and endocrine gland secretion. However, said Takahashi, there had also been intriguing connections between circadian rhythms and the effects of drugs of addiction. For example, drug addiction is associated with disruptions in sleep and circadian rhythmicity. And animal studies have shown a circadian effect of drug self-administration, which suggested that there may be a connection between the brain's circadian and reward pathways. © 2005 Howard Hughes Medical Institute.

Keyword: Biological Rhythms; Drug Abuse
Link ID: 7500 - Posted: 06.24.2010

Peter Pressman of the Cedars Sinai Medical Center in Beverly Hills, Calif. and Roger Clemens of the University of Southern California School of Pharmacy explain. Food craving, defined as an intense desire to eat a specific foodstuff, is a common occurrence across all cultures and societies. These yearnings, and those associated with nonfoodstuffs such as pagophagia (the practice of consuming ice) and geophagia (literally, earth-eating), are not linked to any obvious nutrient insufficiency. In some individuals food cravings and dietary restriction may be related; however, these observations are inconsistent with the majority of published studies. A number of mechanisms have been advanced to explain the physiological and pathological changes in behavior that lead to food cravings and a loss of control of over eating. The latter, of course, is a major concern with obesity and a number of eating disorders. Researchers have employed functional magnetic resonance imaging (fMRI) to explore the neural basis of cravings and the imaging data suggest that components of the amygdala, anterior cingulate, orbital frontal cortex, insula, hippocampus, caudate and dorsolateral prefrontal cortex are activated during periods of pining for food. It appears that there may be a network of neural regions that is involved with the emotion, memory and chemosensory stimuli of food craving. Eating is generally a pleasurable social experience. Using chocolate consumption as an example, it follows that there may be constituents in chocolate that influence satiation or alter our acceptance of the treat, including psychoactive or mood-altering endogenous compounds such as phenylethylamine, tyramine, serotonin, tryptophan and magnesium. It is important to note, however, that many other foods, including dairy products, also contain these compounds at higher concentrations but tend to have somewhat lesser appeal than chocolate does. © 1996-2005 Scientific American, Inc

Keyword: Obesity
Link ID: 7499 - Posted: 06.24.2010

By Lisa Melton Snoring is not just a recipe for marital discord; it can be life-threatening, too, when it is a part of sleep apnea. This disorder, in which breathing stops many times a night, can detonate dangerous cardiovascular stress. But scientists have long puzzled over why we should respond so fiercely to dips in the oxygen supply. Now a new study has identified the tissue and chemical changes that stir up the problem, a finding that could lead to novel drug treatments. In North America as many as 24 percent of adults suffer from sleep-disordered breathing, a problem exacerbated by obesity. People with obstructive sleep apnea cease breathing for about 15 seconds, every few minutes, hundreds of times a night. Besides feeling drowsy and exhausted the next day, people with sleep apnea face high blood pressure and risk heart attacks and stroke. Indeed, they are about three times as likely to die from a heart attack in the middle of the night as the general population, according to a study in the March 24 New England Journal of Medicine. "The consequences of this intermittent [oxygen deprivation], if it persists for years, can be very drastic," says physiologist Nanduri R. Prabhakar of Case Western Reserve University. Prabhakar has long been mystified by sleep apnea: Why does a brief shutdown of oxygen intake spark an extreme cardiovascular response? After all, people living at high altitude--for example, in the Andes--adapt perfectly well to a low-oxygen environment without developing hypertension. © 1996-2005 Scientific American, Inc

Keyword: Sleep
Link ID: 7498 - Posted: 06.24.2010