By Coco Ballantyne Liquid H2O is the sine qua non of life. Making up about 66 percent of the human body, water runs through the blood, inhabits the cells, and lurks in the spaces between. At every moment water escapes the body through sweat, urination, defecation or exhaled breath, among other routes. Replacing these lost stores is essential but rehydration can be overdone. There is such a thing as a fatal water overdose. Earlier this year, a 28-year-old California woman died after competing in a radio station's on-air water-drinking contest. After downing some six liters of water in three hours in the "Hold Your Wee for a Wii" (Nintendo game console) contest, Jennifer Strange vomited, went home with a splitting headache, and died from so-called water intoxication. There are many other tragic examples of death by water. In 2005 a fraternity hazing at California State University, Chico, left a 21-year-old man dead after he was forced to drink excessive amounts of water between rounds of push-ups in a cold basement. Club-goers taking MDMA ("ecstasy") have died after consuming copious amounts of water trying to rehydrate following long nights of dancing and sweating. Going overboard in attempts to rehydrate is also common among endurance athletes. A 2005 study in the New England Journal of Medicine found that close to one sixth of marathon runners develop some degree of hyponatremia, or dilution of the blood caused by drinking too much water. © 1996-2007 Scientific American, Inc.

Keyword: Miscellaneous
Link ID: 10450 - Posted: 06.24.2010

Some people with schizophrenia who become violent may do so for reasons unrelated to their current illness, according to a new study analyzing data from the Clinical Antipsychotic Trials for Intervention Effectiveness (CATIE). CATIE was funded by the National Institutes of Health’s National Institute of Mental Health (NIMH). The study was published online on June 30, 2007, in the journal Law and Human Behavior. “Most people with schizophrenia are not violent,” said NIMH Director Thomas R. Insel, M.D. “But this study indicates that the likelihood of violence is higher among people with schizophrenia who also have a history of other disorders, namely childhood conduct problems.” Using data from 1,445 CATIE participants, Jeffrey Swanson, Ph.D., of Duke University, and colleagues examined the relationship between childhood antisocial behavior, including conduct disorder symptoms, and adult violence among people with schizophrenia. The overall percentage of participants who committed acts of violence was 19 percent. Those with a history of childhood conduct problems reported violence twice as frequently (28 percent) as those without conduct problems (14 percent). In both groups, violence was more likely among those who were unemployed or underemployed, living with family or in restrictive settings (such as a halfway house or hospital), been recently arrested, or involved with the police. Violence was associated with alcohol and substance abuse in both groups.

Keyword: Schizophrenia
Link ID: 10449 - Posted: 06.24.2010

Louis Buckley Rats that benefit from the charity of others are more likely to help strangers get a free meal, researchers have found. This phenomenon, known as 'generalized reciprocity', has only ever been seen before in humans. A good example, says Michael Taborsky of the University of Bern, Switzerland, is what happens when someone finds money in a phone box. In controlled experiments such people have been shown to be much more likely to help out a stranger in need following their good luck. In humans, such benevolence can be explained by cultural factors as well as by underlying biology, says Taborsky. But if similar behaviour can be found in other animals, he reasons, an evolutionary explanation would be far more likely. To test for this behaviour in animals, Taborsky trained rats to pull a lever that produced food for its partner, but not for itself. Rats who had received a free meal in this way were found to be 20% more likely to help out an unknown partner than rats who had received no such charity1. Taborsky believes this behaviour isn't confined to just rats and humans. "I'm convinced generalized reciprocity will be very widespread and found in many different animal species, as our study suggests that an underlying evolutionary mechanism is responsible." ©2007 Nature Publishing Group

Keyword: Evolution
Link ID: 10448 - Posted: 06.24.2010

By Rob Stein Scientists reported yesterday that they have uncovered a biological switch by which stress can promote obesity, a discovery that could help explain the world's growing weight problem and lead to new ways to melt flab and manipulate fat for cosmetic purposes. In a series of experiments on mice, researchers showed that the neurochemical pathway they identified promotes fat growth in chronically stressed animals that eat the equivalent of a junk-food diet. The international team also showed that blocking those signals can prevent fat accumulation and shrink fat deposits and that stimulating the pathway can strategically create new deposits -- possibly offering new ways to remove fat as well as to mold youthful faces, firmer buttocks and bigger breasts. "It's very exciting," said Zofia Zukowska of Georgetown University's Department of Physiology and Biophysics, who led the research, published online by the journal Nature Medicine. "This could be revolutionary." While cautioning that the safety and effectiveness of the approach remain to be proven in people, other researchers said the findings reveal new clues about the basic biology of fat and why obesity has been increasing so quickly, particularly in Western countries. "There is a lot of uncontrollable stress right now in our societies. There's also a lot of inexpensive high-fat food," said Mary F. Dallman of the University of California at San Francisco, who co-wrote a commentary accompanying the research. "This could help explain the obesity epidemic." © 2007 The Washington Post Company

Keyword: Obesity
Link ID: 10447 - Posted: 06.24.2010

By BENEDICT CAREY AT times, adult life can feel like an extended exercise in escaping high school, a scramble to shed wallflower memories, to show all those snickering swells what happens when a worm grows wings or a spine (or a hedge fund). A study released a little over a week ago, which found that eldest children end up, on average, with slightly higher I.Q.’s than younger siblings, was a reminder that the fight for self-definition starts much earlier than freshman year. Families, whatever the relative intelligence of their members, often treat the firstborn as if he or she were the most academic, and the younger siblings fill in other niches: the wild one, the flirt. These imposed caricatures, in combination with the other labels that accumulate from the sandbox through adolescence, can seem over time like a miserable entourage of identities that can be silenced only with hours of therapy. But there’s another way to see these alternate identities: as challenges that can sharpen psychological skills. In a country where reinvention is considered a birthright, many people seem to treat old identities the way Houdini treated padlocked boxes: something to wriggle free from, before being dragged down. And psychological research suggests that this ability can be a sign of mental resilience, of taking control of your own story rather than being trapped by it. Copyright 2007 The New York Times Company

Keyword: Intelligence
Link ID: 10446 - Posted: 06.24.2010

Rowan Hooper Yawning is not something we usually aim to provoke among our readers, but have a yawn now. Does your brain feel cooler? Do you feel more attentive? According to psychologists Andrew Gallup and Gordon Gallup of the State University of New York at Albany, that is why we yawn: to boost blood flow and chill the brain. Not only that, brain-cooling explains why you can "catch" a yawn, says Gordon Gallup. "We think contagious yawning is triggered by empathic mechanisms which function to maintain group vigilance." In other words, yawn-catching evolved to help raise the attentiveness of the whole group. The pair recruited 44 college students to watch, individually, films of people yawning and recorded the number of contagious yawns each volunteer made. Students were told to inhale and exhale in one of four ways: strictly orally; strictly nasally; orally while wearing a nose plug; or just breathe normally. Fifty per cent of people told to breathe normally or through their mouths yawned while watching other people yawn, while none of those told to breathe through their noses yawned. The researchers also found that subjects who held a cold pack to their forehead did not catch yawns from the film, while those who held a warm or room-temperature pack yawned normally (Evolutionary Psychology, vol 5, p 92). © Copyright Reed Business Information Ltd.

Keyword: Sleep
Link ID: 10445 - Posted: 06.24.2010

Helen Pilcher Female mice make new brain cells when they detect a dominant male's urine, researchers have found. The discovery gives a clue as to how the chemical messages shape their receiver's taste in mates. Urine is rich in the sex pheromones that many animals use to recognize and choose their mates. But how they work is unclear. So Samuel Weiss from the University of Calgary in Alberta, Canada, and his colleagues looked at their effects on the brain. The team housed adult female mice with soiled litter for a week. Animals exposed to urine from dominant males showed around a 25% increase in new neurons in two brain regions. Those exposed to clean bedding, or urine from females or subordinate males showed no such increase. The results, published in Nature Neuroscience1, suggest that pheromones from dominant males stimulate the female brain to make new neurons. Female mice prefer dominant males, but females given a chemical that blocks neuron production became indifferent to status. "Adult neurogenesis may be involved in female mate selection," says Weiss. ©2007 Nature Publishing Group

Keyword: Hormones & Behavior; Neurogenesis
Link ID: 10444 - Posted: 06.24.2010

Proteins which cause mad cow disease may also protect against Alzheimer's disease, UK researchers say. Prions naturally present in the brain appear to prevent the build up of a key protein associated with the condition. In laboratory tests, beta amyloid, the building block of Alzheimer's "plaques", did not accumulate if high levels of the prions were present. The findings could lead to new treatments, the Proceedings of the National Academy of Sciences reported. In variant Creutzfeldt-Jakob disease (vCJD), the human version of mad cow disease, the normal version of the prion protein present in brain cells is corrupted by infectious prions causing it to change shape, resulting in brain damage and death. But little is known about purpose of the normal prion proteins. Due to the similarities between Alzheimer's and diseases such as variant CJD, researchers at the University of Leeds, looked for a link. They found that in cells in the laboratory, high levels of the prions reduced the build-up of beta-amyloid protein, which is found in the brains of people with Alzheimer's disease. In comparison, when the level of the prions was low or absent, beta amyloid formation was found to go back up again, suggesting they have a preventive effect on the development of the condition. The researchers also looked at mice who had been genetically engineered to lack the prion proteins and again found that the harmful beta-amyloid proteins were able to form. (C)BBC

Keyword: Alzheimers; Prions
Link ID: 10443 - Posted: 06.30.2007

By GARDINER HARRIS WASHINGTON, — As states begin to require that drug companies disclose their payments to doctors for lectures and other services, a pattern has emerged: psychiatrists earn more money from drug makers than doctors in any other specialty. How this money may be influencing psychiatrists and other doctors has become one of the most contentious issues in health care. For instance, the more psychiatrists have earned from drug makers, the more they have prescribed a new class of powerful medicines known as atypical antipsychotics to children, for whom the drugs are especially risky and mostly unapproved. Vermont officials disclosed Tuesday that drug company payments to psychiatrists in the state more than doubled last year, to an average of $45,692 each from $20,835 in 2005. Antipsychotic medicines are among the largest expenses for the state’s Medicaid program. Over all last year, drug makers spent $2.25 million on marketing payments, fees and travel expenses to Vermont doctors, hospitals and universities, a 2.3 percent increase over the prior year, the state said. The number most likely represents a small fraction of drug makers’ total marketing expenditures to doctors since it does not include the costs of free drug samples or the salaries of sales representatives and their staff members. According to their income statements, drug makers generally spend twice as much to market drugs as they do to research them. Copyright 2007 The New York Times Company

Keyword: Schizophrenia; Depression
Link ID: 10442 - Posted: 06.24.2010

Bruce Bower Many researchers have asserted that only people will assist strangers without receiving anything in return, sometimes at great personal cost. However, a new study suggests that chimpanzees also belong to the Good Samaritan club, as do children as young as 18 months of age. Without any prospect of immediate benefit, chimps helped both people and other chimps that they didn't know, and the 18-month-olds spontaneously assisted adults they'd never seen before, say psychologist Felix Warneken of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his colleagues. The roots of human altruism reach back roughly 6 million years to a common ancestor of people and chimps, the researchers propose in the July PLoS Biology. "Learning and experience are involved in altruistic helping, but our claim is that there is a predisposition [in chimps and people] to develop such behavior without explicit training," Warneken says. His team conducted three experiments with adult chimps living on an island sanctuary in Uganda and two experiments with 18-month-old German children. In the chimp version of the first experiment, 36 animals watched one at a time from a barred enclosure as an experimenter in an adjacent room—who had had virtually no prior contacts with the animals—reached through the bars for a stick on the other side. The stick was within reach of only the observing chimp. ©2007 Science Service

Keyword: Evolution; Emotions
Link ID: 10441 - Posted: 06.24.2010

Many people with early dementia can drive safely, a survey has suggested. The risk of crashes among Alzheimer's patients is "acceptably low" for up to three years after the disease becomes clinically apparent, they claim. The conclusions in the British Medical Journal are based on medical data published between 1966 and 2007. Anyone holding a UK driving licence must, by law, inform the DVLA if they have a medical condition that might affect the safety of their driving. The DVLA says that people with poor short-term memory are a higher risk and should not be driving. Lead researcher Professor Desmond O'Neill, of the Trinity Centre for Health Sciences and Meath Hospital in the Republic of Ireland, says there is a misconception about the impact of age-related disease on driving. He said many medical journals had reported an apparent increase in crashes per mile driven for older people, yet several studies have established that this is related to low mileage rather than to age. And surveys of drivers aged more than 80 consistently show prudent driving behaviours, said Professor O'Neill. He says the challenge for doctors and the licensing agency is to balance mobility and safety in a growing population of older drivers. Stopping driving can limit access to family, friends, and services and is an independent risk factor for entry into a nursing home, he said. (C)BBC

Keyword: Alzheimers
Link ID: 10440 - Posted: 06.29.2007

Children with cerebral palsy are just as happy as children without the condition are, a study has shown. Their physical impairment does not have a negative effect on their relationships, moods or welfare, researchers report in The Lancet. Experts said the study of 500 children aged 8-12 years with cerebral palsy underlined the importance of supporting disabled children to lead full lives. Cerebral palsy affects around one in 400 children in the UK. It results from the failure of a part of the brain to develop before birth or in early childhood, or brain damage which permanently affects body movement and muscle coordination. Most children with cerebral palsy are born with it, although it may not be detected until months or years later. Previous studies have attempted to look at the quality of life of children with cerebral palsy but they focused on physical effects of the condition or relied on the views of parents. A team of European researchers, led by the University of Newcastle, asked the children themselves about several aspects of their lives and compared their responses with those from children of the same age in the general population. The questionnaire covered areas such as physical and psychological wellbeing, moods and emotions, self-perception and relationships with parents, friends and school. On most of the areas, children with cerebral palsy had similar scores to the general population. The only exceptions were schooling for which the results were not clear and physical wellbeing which could not be compared. (C)BBC

Keyword: Development of the Brain
Link ID: 10439 - Posted: 06.29.2007

Italian scientists have developed a pill that expands in the stomach to make dieters feel full. They liken the effect to eating a bowl of spaghetti and say the pill can stop hunger for a few hours. It is made from a hydrogel, which the team developed when trying to make more absorbent nappy linings, and may help in the battle against obesity. So far it has been tested on 20 people but experts warned bigger trials would be needed to test safety. Professor Luigi Ambrosio, lead researcher on the study at Italy's National Research Council, realised when they developed the hydrogel it may have a similar effect to gastric banding - a surgical procedure that reduces the size of the stomach. The tiny pill is powdery when dry but when swallowed with a glass of water turns to a jelly-like ball in the stomach. It is made from an organic compound called cellulose so can break down in the body and pass through the digestive system. The pill, which has yet to be named, is being tested in a further 90 overweight volunteers who will be monitored to see how much weight they lose and if there are any adverse effects. Professor Ambrosio said the pill should be taken about 30 minutes to one hour before each meal. It passes through the digestive system within five to six hours. "One of our researchers tried the pill - he took it at about 11am and was still full at six in the evening. It's like eating a bowl of spaghetti." (C)BBC

Keyword: Obesity
Link ID: 10438 - Posted: 06.29.2007

Alex Quinn Species in the genotypic group, like mammals and birds, have sex chromosomes, which in reptiles come in two major types. Many species—such as several species of turtle and lizards, like the green iguana—have X and Y sex chromosomes (again, like mammals), with females being "homogametic," that is, having two identical X chromosomes. Males, on the other hand, are "heterogametic," with one X chromosome and one Y chromosome. Other reptiles governed by GSD have a system, similar to one found in birds, with Z and W sex chromosomes. In this case—which governs all snake species—males are the homogametic sex (ZZ) and females are the heterogametic sex (ZW). In temperature-dependent sex determination, however, it is the environmental temperature during a critical period of embryonic development that determines whether an egg develops as male or female. This thermosensitive period occurs after the egg has been laid, so sex determination in these reptiles is at the mercy of the ambient conditions affecting egg clutches in nests. For example, in many turtle species, eggs from cooler nests hatch as all males, and eggs from warmer nests hatch as all females. In crocodilian species—the most studied of which is the American alligator—both low and high temperatures result in females and intermediate temperatures select for males. A widely held view is that temperature-dependent and genotypic sex determination are mutually exclusive, incompatible mechanisms—in other words, a reptile's sex is never under the influence of both sex chromosomes and environmental temperature. © 1996-2007 Scientific American, Inc.

Keyword: Sexual Behavior
Link ID: 10437 - Posted: 06.24.2010

Andy Coghlan One of the nasty tricks that diabetes has up its sleeve is the ability to carry on harming people long after they have got the level of glucose in their blood under control. Now researchers think they may be able to stop this, using cheap available drugs. The idea builds on the discovery that when cells are exposed to the high levels of glucose typical of diabetes, proteins within the cells' mitochondria suffer damaging changes. The proteins become permanently attached to sugar-like molecules called glycans, and this not only prevents them doing their job properly but also makes them produce harmful molecules called reactive oxygen species. The reactive oxygen species circulate throughout the body, attacking and damaging tissues, particularly in the limbs and eyes. Because the changes to the cellular proteins are not reversible, they continue to pump out these molecules even when glucose levels have returned to normal. "This contributes to the development of diabetic complications," says Antonio Ceriello of the University of Warwick in Coventry, UK, whose team now think there may be a way to stop this happening. The clue came from lab experiments in which they took damaged cells that had been previously exposed to high levels of glucose, and showed that the reactive molecules could be neutralised by exposing the cells to antioxidants such as alpha-lipoic acid (Diabetologia, DOI: 10.1007/s00125-007-0684-2). © Copyright Reed Business Information Ltd.

Keyword: Obesity
Link ID: 10436 - Posted: 06.24.2010

Analyses of a national sample of individuals with alcohol dependence (alcoholism) reveal five distinct subtypes of the disease, according to a new study by scientists at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health (NIH). "Our findings should help dispel the popular notion of the ‘typical alcoholic,’” notes first author Howard B. Moss, M.D., NIAAA Associate Director for Clinical and Translational Research. “We find that young adults comprise the largest group of alcoholics in this country, and nearly 20 percent of alcoholics are highly functional and well-educated with good incomes. More than half of the alcoholics in the United States have no multigenerational family history of the disease, suggesting that their form of alcoholism was unlikely to have genetic causes.” “Clinicians have long recognized diverse manifestations of alcoholism,” adds NIAAA Director Ting-Kai Li, M.D, “and researchers have tried to understand why some alcoholics improve with specific medications and psychotherapies while others do not. The classification system described in this study will have broad application in both clinical and research settings.” A report of the study is now available online in the journal Drug and Alcohol Dependence. Previous efforts to identify alcoholism subtypes focused primarily on individuals who were hospitalized or otherwise receiving treatment for their alcoholism.

Keyword: Drug Abuse
Link ID: 10435 - Posted: 06.24.2010

By BENEDICT CAREY Taking an antidepressant like Prozac may increase a pregnant woman’s risk of having a baby with a birth defect, but the chances appear remote and confined to a few rare defects, researchers are reporting today. The findings, appearing in two studies in The New England Journal of Medicine, support doctors’ assurances that antidepressants are not a major cause of serious physical problems in newborns. But the studies did not include enough cases to adequately assess risk of many rare defects; nor did they include information on how long women were taking antidepressants or at what doses. The studies did not evaluate behavioral effects either; previous research has found that babies suffer withdrawal effects if they have been exposed to antidepressants in the womb, and that may have implications for later behavior. “These are important papers, but they don’t close the questions of whether there are major effects” of these drugs on developing babies, said Dr. Timothy Oberlander, a developmental pediatrician at the University of British Columbia, who was not involved in the studies. “There are many more chapters in this story yet to be told.” Copyright 2007 The New York Times Company

Keyword: Depression; Development of the Brain
Link ID: 10434 - Posted: 06.24.2010

Symptoms of mental retardation and autism have been reversed for the first time in laboratory mice. US scientists created mice that showed symptoms of Fragile X Syndrome - a leading cause of mental retardation and autism in humans. They then reversed symptoms of the condition by inhibiting the action of an enzyme in the brain. The study, by Massachusetts Institute of Technology, appears in Proceedings of the National Academy of Sciences. Fragile X Syndrome is linked to mutation in a gene carried on the X chromosome called FMR1. It can cause symptoms ranging from mild learning disabilities to severe autism. The researchers, based at MIT's Picower Institute for Learning and Memory, targeted an enzyme called PAK which affects the number, size and shape of connection between brain cells. They found that inhibiting the enzyme stopped mice with Fragile X Syndrome behaving in erratic ways. Prior to treatment they showed signs of hyperactivity, purposeless and repetitive movements. Further analysis showed that not only were structural abnormalities in connections between brain cells righted, proper electrical communication was restored between the cells. In the brain small protrusions called dendritic spines are responsible for communication between cells. People with Fragile X Syndrome have more dendritic spines than usual, but each is longer and thinner, and transmits weaker electric signals. Blocking PAK activity in the lab mice corrected these abnormalities. (C)BBC

Keyword: Autism; Genes & Behavior
Link ID: 10433 - Posted: 06.28.2007

By Melinda Wenner Female timber rattlesnakes tend to be stay-at-home moms while the males wander the streets — sometimes even suburban streets, according to new research. A team of researchers is seeking out these sneaky rattlers, implanting tracking devices inside them and then turning them loose in order to learn more about their behavior. Wayne Drda, a researcher at the Tyson Research Center at Washington University in St. Louis, and his colleagues recently also learned that, contrary to popular belief, timber rattlesnakes are shy and rarely use their rattlers. This is because they are well camouflaged, and rattling gives away their location. They have also found that females and males behave quite differently. While the females stay with their young for up to 10 days after birth, the males prefer to wander around. Most snakes, however, do return to the same sites year after year. Unfortunately for the snakes, their wanderlust — as well as their tendency to pop up in suburban neighborhoods, where families have unknowingly encroached upon their turf — puts them in danger of being killed by fearful residents. © 2007 MSNBC.com © 2007 Microsoft

Keyword: Sexual Behavior
Link ID: 10432 - Posted: 06.24.2010

By NATALIE ANGIER Not long ago, my daughter proposed a way she could earn some extra cash beyond her weekly allowance. Would I give her a quarter, she wanted to know, every time she cleaned the cat box? Twenty-five cents to clean the cat box? I squealed with unconcealed joy. Truly we’d hit commensal pay dirt here. She had fiscal motivation, and I could use the olfactory vacation. But then I read a few items about Toxoplasma gondii, the parasitic protozoa that can be lurking in cat scat, and I changed my mind. I told my daughter that she should skip the litter patrol and try cleaning the refrigerator instead. I’m not normally a fluttering, overprotective mother, and I know that the risk of contracting the toxoplasma pathogen or any serious infectious illness from the cat box is tiny. Still, we’re talking parasites here, and parasitism is an evolutionary force to be reckoned with, a source of nearly bottomless cunning and breathtaking bio-inventiveness. Predators want to kill you and eat you right there on the veldt. Parasites, by contrast, want to keep you alive, the better to serve as a parasite paradise, a cozy haven where they can grow at their own pace, suckle on your moist, nourishing tissues, multiply their numbers and finally, one way or another, pass those numbers along. Toxoplasma, it seems, is a member of a particularly insidious genus of parasite, which seek perpetuity by controlling their hapless hosts’ minds. So maybe I’m hyperventilating here, but if any mind in my house is to be monkeyed with, I would really prefer it be mine. Copyright 2007 The New York Times Company

Keyword: Miscellaneous
Link ID: 10431 - Posted: 06.24.2010