A study of twins suggests that a gene key to eye development plays a crucial role in people becoming short-sighted. Researchers from St Thomas' Hospital in London said faulty versions of the PAX6 gene could make people more susceptible to the condition. But they said sitting too close to the TV or playing too many computer games could exacerbate someone's risk. Around a quarter of the UK population are short-sighted, but it has reached epidemic proportions in the Far East. In Japan, two thirds of teenagers are already myopic. The problem is said to even worse in Singapore, where 80% of 18-year-old male army recruits are short sighted, compared with 25% just 30 years ago. The problem in Singapore is so bad that employers such as the police are struggling to find people who meet their requirements. Previous research looking at whether the causes of short-sightedness (myopia) were genetic or environmental had found inherited factors accounted for 89%, and the environment 11%. (C)BBC

Keyword: Vision; Genes & Behavior
Link ID: 5905 - Posted: 07.29.2004

In 2002, researchers from Imperial College in London discovered that a natural hormone made in the gut called PYY3-36 appears to signal to the brain that the stomach is full. They reported it reduced food intake and body weight in rodents, and in a small study in humans. "By giving this hormone we naturally cause the brain to feel less like eating, and this is an important breakthrough in the possibilities for treating obesity," Steve Bloom, a researcher at Hammersmith Hospital and professor at Imperial College, told ScienCentral last year. "This is a very interesting discovery because for once, the scientist has found something that means an active treatment quite quickly. And what we are hoping is that we will be able to go to a direct demonstration of real weight loss and no side effects." But for those or any scientific results to be accepted by other scientists, they need to be confirmed in similar experiments. Obesity researcher Matthias Tschoep was one of 42 scientists from 12 different labs around the world that independently tested PYY3-36 in rodents. His lab at the University of Cincinnati Medical Center's Genome Research Institute repeatedly failed to see the same results, finding no significant effect on food intake or body weight. © ScienCentral, 2000- 2004.

Keyword: Obesity
Link ID: 5904 - Posted: 06.24.2010

To date epilepsy research has mainly concentrated on the transmission of the nerve cell signals to what are known as the synapses. However, recent observations by medical researchers from the US, France and the University of Bonn support the idea that in 'falling sickness' the signal processing in the nerve cells (neurons) is altered: normally specific ion channels absorb the neuronal activity. In rats suffering from epilepsy, however, this signals brake seems impaired: they have far fewer functioning ion channels than healthy rats. The results are published in the latest edition of the prestigious scientific journal 'Science' (23rd July, vol. 305, no. 5683). They offer hope of new therapeutic possibilities. Epilepsy is a common disease: in Germany alone there are 600,000 people whose nerve cells in the brain occasionally switch from healthy chaos to common mode. The result of the uncontrolled mass discharge of neurons is loss of consciousness and spastic convulsions of the muscles, during which those affected can seriously injure themselves. Yet how this synchronised paroxysmic activity develops at the level of nerve cells is still largely a mystery. Nerve cells are interlinked via a large number of branching networks through which they communicate with each other. Each neuron has a series of dendrites which receive signals from other neurons at what are known as synapses. The cell 'processes' these incoming signals like a kind of biological microprocessor and transmits as a result electrical pulses via a special projection, the axon, to the dendrites of other neurons.

Keyword: Epilepsy
Link ID: 5903 - Posted: 07.29.2004

By Jennifer Viegas, Discovery News — Butterflies may seem to be silent loners, but new research reveals that many species of these colorful insects actively communicate with one another using Morse Code-like clicks, according to a recent University of Florida press release. The finding adds to the growing body of evidence that many insects can hear and that they communicate using sound. The research might also help humans. Studies on the tiny auditory organs of butterflies could lead to the development of improved hearing aids and miniature microphones. UF researcher Mirian Hay-Roe first heard the butterfly clicks when she shared greenhouse space with a colleague who was working with blue and white longwing butterflies, Heliconius cydno. The longwings seemed to bully Hay-Roe's butterflies, which were a different species. They chased the insect newcomers around the greenhouse. It was during the air turf war that Hay-Roe heard a number of faint clicks. As the longwings flew, they often clicked to each other and apparently to the interlopers. Copyright © 2004 Discovery Communications Inc.

Keyword: Animal Communication; Hearing
Link ID: 5902 - Posted: 06.24.2010

Ground squirrels emit an ultrasound squeal to warn other animals that a predator is approaching, researchers have discovered. Bats and toothed whales are already known to use ultrasound for echolocation, but little is known about ultrasound communication in the rest of the animal kingdom. Some rodents, including rats and hamsters, emit ultrasound calls, but no one is sure what they mean. To investigate, David Wilson and James Hare of the University of Manitoba in Winnipeg, Canada, studied how Richardson's ground squirrels (Spermophilus richardsonii), a burrowing rodent, responded to the approach of humans. Usually, the animals made audible alarm calls, opening their mouths wide and thrusting their bodies forward. But occasionally, a squirrel would do this but make no sound, its open mouth producing only a faint whisper of rushing air. © Copyright Reed Business Information Ltd.

Keyword: Hearing; Animal Communication
Link ID: 5901 - Posted: 06.24.2010

Scientists isolate nerve cells that choreograph male fly's courtship behavior When a male fruit fly encounters a prospective mate, he initiates courtship by following her around and gently tapping her with his leg. If she seems interested, he serenades her with a love song. Singing is followed by more intimate acts that sometimes lead to successful mating. Now Stanford University scientists have discovered that this elaborate courtship behavior is actually choreographed by a cluster of nerve cells embedded in the central nervous system of the male fly. When these cells fail to function properly, the courtship ritual breaks down and the male is transformed from a suave Casanova into a clumsy brute that tries to force himself on unwilling females. These findings, published in the July 29 edition of the journal Nature, may eventually help scientists understand how the brain orchestrates sexual behavior in a variety of species - from flies to reptiles to humans, according to the researchers. "The fruit fly is a model organism whose basic cellular functions are very similar to what they are in people," said Bruce S. Baker, the Dr. Morris Herzstein Professor in Biology at Stanford and co-author of the Nature study. "It wouldn't surprise me to learn that human sexual behaviors also have underneath them a basic circuitry in the nervous system that mediates attraction and mating."

Keyword: Sexual Behavior
Link ID: 5900 - Posted: 07.29.2004

Infusions migrated to damaged spots in test rats' brains David Perlman, Chronicle Science Writer Stem cells derived from human fetuses and used in early experiments with anesthetized rats show long-term promise in treating strokes, according to a team of Stanford University brain researchers. The stem cells have shown the ability to migrate into spaces filled with dead brain cells in laboratory rats suffering from the same types of strokes that can disable and kill humans, the scientists report. In human stroke victims, an abrupt loss of blood supply to the brain can kill various types of neurons as well as other brain and blood cells. In the new experiments, researchers led by Dr. Gary Steinberg, a Stanford neurosurgeon, infused fetal stem cells close to the spots in the rat brains where stroke-killed cells created a gap in the network of normal neurons. The experiments and their results are being described by Steinberg and his Stanford group in the current online edition of the Proceedings of the National Academy of Sciences. ©2004 San Francisco Chronicle

Keyword: Stroke; Stem Cells
Link ID: 5899 - Posted: 06.24.2010

Up to three in 10 people who are injured do not recover as quickly as expected for psychological reasons, according to new study. In 5% to 10% of cases a minor physical injury becomes a major problem, affecting insurance claims and the length of time off work, it found. The work was done for the Association of British Insurers and International Underwriting Association. Insurers want to intervene earlier to prevent cases becoming too expensive. The report found that the recovery of between 20% and 30% of people injured in car accidents or at work was hampered by psychological factors. The organisations commissioned the research after evidence showed factors such as depression were affecting people's recovery from accidents. The report said the problem helps to explain why many injury claims take much longer to settle and at far greater cost than first seemed likely. Chief executive of the Motor Insurers' Bureau Ashton West, who chaired the research panel, said insurers would usually expect injuries such as back sprain or whiplash to clear up quickly. (C)BBC

Keyword: Neuroimmunology; Depression
Link ID: 5898 - Posted: 07.28.2004

Just a few months ago, a paper was published, with very little fanfare, in an obscure medical journal. But the contents of the paper were astonishing. In it was a potential solution to what has been called the biggest medical mystery of all time. Two young doctors had tracked down the probable cause of one of the most baffling epidemics of the 20th Century - a disease called Encaphilitis Lethargica. Encaphilitis Lethargica was a devastating illness that swept the world in the 1920's. It attacked the brain, leaving victims like living statues, speechless and motionless. During the outbreak, nearly a million died, and millions more were left frozen inside their useless bodies, in institutions. Noone knew what had caused it, or how to treat it. For virologist Professor John Oxford, the disease was not just a disease of the past. As an expert on the condition, he was convinced that it could reappear. "I certainly do think that whatever caused it could strike again. And until we know what caused it we won't be able to prevent it happening again." And in 1993, it seemed his fears were being realised. (C)BBC

Keyword: Parkinsons
Link ID: 5897 - Posted: 07.28.2004

By Hunter G. Hoffman In the science-fiction thriller The Matrix, the heroes "plugged in" to a virtual world. While their bodies rested in reclining chairs, their minds fought martial-arts battles, dodged bullets and drove motorcycles in an elaborately constructed software program. This cardinal virtue of virtual reality--the ability to give users the sense that they are "somewhere else"--can be of great value in a medical setting. Researchers are finding that some of the best applications of the software focus on therapy rather than entertainment. In essence, virtual reality can ease pain, both physical and psychological. For the past several years, I have worked with David R. Patterson, a pain expert at the University of Washington School of Medicine, to determine whether severely burned patients, who often face unbearable pain, can relieve their discomfort by engaging in a virtual-reality program during wound treatment. The results have been so promising that a few hospitals are now preparing to explore the use of virtual reality as a tool for pain control. In other projects, my colleagues and I are using virtual-reality applications to help phobic patients overcome their irrational fear of spiders and to treat post-traumatic stress disorder (PTSD) in survivors of terrorist attacks. At least two software companies are already leasing virtual-reality programs and equipment to psychologists for phobia treatment in their offices. And the Virtual Reality Medical Center, a chain of clinics in California, has used similar programs to successfully treat more than 300 patients suffering from phobias and anxiety disorders. Although researchers must conduct more studies to gauge the effectiveness of these applications, it seems clear that virtual therapy offers some very real benefits. © 1996-2004 Scientific American, Inc.

Keyword: Pain & Touch; Robotics
Link ID: 5896 - Posted: 06.24.2010

Crayfish catch z's much like mammals do, a new study finds. When the crustaceans crash out, their brains emit slow waves of electricity surprisingly similar to those seen in the brains of slumbering mammals. In terms of behavior, sleep is characterized by an animal's indifference to the outside world and its need to compensate for doze deficits. In mammals and other vertebrates, sleep also evokes slow, regular waves of electrical activity in the brain. However, although studies in fruit flies and bees hint at proper sleep, slow waves have not been found in these animals. Now, in a paper published online this week in the Proceedings of the National Academy of Sciences, researchers report that crayfish exhibit slow waves, as well as the behavioral signs of sleep. Fidel Ramón of the National Autonomous University of Mexico and his colleagues first watched crayfish (Procambarus clarkia) around the clock. They noticed that when the animals struck a particular pose, lying motionless on one side and holding on to the tank with just one appendage, they also seemed practically comatose. These groggy animals were less responsive to being shaken by a motor--the equivalent of a cell phone on vibrate--compared to animals strutting around the bottom of aquaria. When the researchers flashed regularly timed lights, like strobes at a disco, the nappers, unlike alert crayfish, didn't seem to notice when the scientists skipped a flash. Finally, the researchers found that sleep-deprived crayfish made up for lost shut-eye the next night, a telltale sign of a regular snoozer. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Sleep
Link ID: 5895 - Posted: 06.24.2010

Fetal alcohol syndrome (FAS) is a permanent condition that can occur in a newborn if a woman drinks alcohol during pregnancy. It's often characterized by abnormal facial features, growth retardation, and central nervous system problems. Children with FAS may have physical disabilities, but the damage may also be limited to problems with learning, memory, attention, and problem solving. "Alcohol is the most widely abused drug in the Western world," says Ann Streissguth, director of the Fetal Alcohol and Drug Unit at the University of Washington. "In our work we find that one per 100 live births are affected by prenatal alcohol exposure and that is so important. That makes it the largest known cause of mental retardation and developmental disabilities." Experts have long warned expectant mothers to not drink, especially early in pregnancy, when the baby's body is forming. John Olney, professor of psychiatry and neuropathology at Washington University in St. Louis, is studying how alcohol hurts the fetal brain in later in the pregnancyby triggering nerve cells, which are just forming connections, to commit suicide. © ScienCentral

Keyword: Drug Abuse; Apoptosis
Link ID: 5894 - Posted: 06.24.2010

Helen Pilcher Lithium, a common treatment for manic depression, might also help to stave off Alzheimer's disease. Patients who take the drug to stabilize their mood disorder are less likely to succumb to dementia, a study reveals. For the last 30 years, lithium has been used to control the mood swings of patients with bipolar disorder, also known as manic depression. But over the last decade, an increased understanding of how the drug works has widened the scope for its use. Researchers now think that the simple salt could slow the progress of degenerative brain disorders, such as Huntington's and Alzheimer's disease. Paula Nunes and colleagues from the University of São Paulo, Brazil, studied 74 elderly people with bipolar disorder. Four percent of those taking lithium had Alzheimer's disease, compared with 21% of patients who were not taking the drug. The researchers conclude that lithium therapy may lower the risk of developing Alzheimer's disease. They presented their data at the 9th International Conference on Alzheimer's Disease and Related Disorders in Philadelphia, Pennsylvania, last week. ©2004 Nature Publishing Group

Keyword: Alzheimers; Depression
Link ID: 5893 - Posted: 06.24.2010

The environment plays an important role in memory retrieval, says a new University of Toronto study. In a study of olfactory learning published in the July 27 issue of Current Biology, U of T's Eric Law, a PhD candidate, and his supervisor, Professor Derek van der Kooy of the Department of Medical Genetics and Microbiology, used C. elegans, a worm whose genome has been completely sequenced, to demonstrate that animals absorb information about their environment and modulate their behaviour accordingly. The researchers first placed worms on agar plates treated with a salt medium, exposed them to the smell of benzaldehyde and trained them to associate the smell with starvation. If a worm was returned to the salt medium where it had been trained, it showed a distaste for the benzaldehyde odour, but it did not demonstrate this memory in a different salt medium. Law likened the results to remembering something more easily if you were in the same environment where you had first learned it. "During training, the worms learn about whether smell predicts starvation, and it becomes apparent that environmental cues can also trigger the memory of odour as a cue for starvation," said Law. "This is something people intuitively said was important. This is an important bridge between psychology and neurobiology. Affecting an environment affects your ability to learn."

Keyword: Learning & Memory
Link ID: 5892 - Posted: 07.28.2004

CHAMPAIGN, Ill. -- Feeling sick can be "all in the head" for people with inflammatory disorders or for those receiving immunotherapy, say Robert Dantzer and Keith Kelley, professors in the department of animal sciences at the University of Illinois at Urbana-Champaign. "For the first time, we have evidence of a strong relationship between a molecular event and the development of psychopathology," Dantzer said. The two scientists, who have collaborated for 25 years, have identified how a molecular pathway in the brain may explain why some patients suffering from inflammatory diseases develop depression. "The goal of our research is to understand the mechanisms that are responsible for causing depression in patients with inflammatory diseases," Dantzer said. Depressive disorders occur in 12 to 30 percent of patients who suffer from various diseases with an inflammatory component, including coronary heart disease and autoimmune diseases such as rheumatoid arthritis and inflammatory bowels. These mood disorders usually are attributed to psychological problems encountered by patients having to deal with the suffering and disability brought about by their diseases.

Keyword: Neuroimmunology; Depression
Link ID: 5891 - Posted: 07.28.2004

By DONALD G. McNEIL Jr. I haven't slept well for years. If I set an alarm for 6:30 a.m., my eyes open at 5, and I try to doze to the radio. I drink four cups of coffee a day. I don't think I have ever fallen asleep at the wheel, but I often pull over nodding off. I used to work nights, which first threw my rhythm off. But I liked having days with my daughters and not being a creature of habit, perhaps because my father, who slept nine hours a night, was someone you could set a clock by. Lately, though, it had gotten ridiculous. So when the new sleep lab at Downstate Medical Center in Brooklyn offered to let me bring my pillow over for a test snooze, I jumped. True sleep disorders can be serious. Apnea sufferers whose blocked throats suppress their blood-oxygen levels below 80 percent saturation can die of arrhythmia or stroke. Narcoleptics suffer car accidents and fall down stairs. People with REM (rapid eye movement) behavior disorder, who lack the normal muscle paralysis that keeps most sleepers from acting out their dreams, have been known to beat and choke their spouses. Copyright 2004 The New York Times Company

Keyword: Sleep
Link ID: 5890 - Posted: 07.27.2004

By NICHOLAS BAKALAR At one time, any surgery under general anesthesia practically mandated a stay in the hospital, often to recover not from the surgery but from the effects of the anesthesia used during the operation. Patients were woozy for hours, unable to get out of bed, nauseated and vomiting, and even if they wanted to eat, they couldn't because their digestive systems were paralyzed. People receiving anesthesia were also at risk; a significant number died not from their disease but from the anesthetic drugs themselves. But new drugs and procedures developed in recent years have made anesthesia not only more comfortable, but much safer. Despite two recent highly publicized deaths from anesthesia in a New York hospital, such events, shocking as they are, do not constitute a trend. On the contrary, deaths from anesthesia in generally healthy patients have made a startling decline in the last two decades, decreasing to an estimated 1 in 250,000 cases from 1 in 10,000, according to the American Society of Anesthesiologists. And new drugs have become so easy to tolerate that many patients can undergo general anesthesia in the morning and be home, completely recovered, in time for dinner. Copyright 2004 The New York Times Company |

Keyword: Pain & Touch
Link ID: 5889 - Posted: 07.27.2004

Using satellite tracking to study the paths pigeons take on homeward-bound journeys, researchers have obtained strong new evidence to support a long-held theory: in some environments, pigeons instinctively learn to follow major roadways in navigating their flight. The new findings are reported by a research group headed by Dr. Hans-Peter Lipp of the University of Zürich. Anecdotal evidence from breeders of racing pigeons as well as initial aerial tracking studies together suggested that pigeons may follow roadways and use highway landmarks as turning points in their flight. However, the challenge of accurately tracking the birds stood in the way of solid quantitative analysis. In the new work, miniaturized GPS "flight-loggers," which pigeons carried on their backs, allowed researchers a clear and reliable picture of the birds' flight paths. Over three years, the researchers analyzed more than 200 flight paths of 20-80 km in length made by pigeons travelling toward their home loft from numerous release sites located in the general vicinity of Rome, Italy. They found that, when released from familiar sites, pigeons with homing experience were significantly attracted to highways and a railway track running in the approximate directions home. When these structures began to veer significantly from the beeline to the loft, some birds tended to break away and head in a more homeward direction, but others took a detour by following the highway until a main junction, at which point they followed a valley road in the direction of the loft.

Keyword: Animal Migration; Learning & Memory
Link ID: 5888 - Posted: 07.27.2004

Rearing experimental animals under special illumination, researchers have found new evidence that early visual experience is indispensable for the development of normal color perception. The wavelength composition of the light reflected from an object changes considerably in different conditions of illumination. Nevertheless, the color of the object remains the same. This property, so-called "color constancy," is the most important property of the color visual system. It has been unclear based on previous work whether the attribute of color constancy is innate or acquired after birth. In work reported this week, researcher Yoichi Sugita of the Neuroscience Research Institute, Tsukuba, Japan, shows that visual experience in early infancy is indispensable for normal development of the color constancy. He raised baby monkeys for nearly a year in a separate room where the illumination came from only monochromatic lights. After extensive training afterwards, the monkeys were able to perform color matching tasks, but their judgment of color similarity was quite different from that of normal animals. Furthermore, they had severe deficits in color constancy; their color vision was very much wavelength-dominated, such that they were unable to compensate for the changes in wavelength composition. These results indicate that early visual experience is indispensable for normal color perception.

Keyword: Vision; Development of the Brain
Link ID: 5887 - Posted: 07.27.2004

PROVIDENCE, R.I. -- For nearly a decade, scientists have known that leptin plays an important fat-burning role in humans. But the map of leptin's path through the body – the key to understanding how and why the hormone works – is still incomplete. Now a small but critical section of that map is charted, based on new research conducted at Brown Medical School and Rhode Island Hospital and at Harvard Medical School and Beth Israel Deaconess Medical Center. The research team found that leptin triggers production of the active form of a peptide – áMSH – in the hypothalamus, the small area in the base of the brain that controls hunger and metabolism. Researchers say this peptide, or small protein, is one of the body's most powerful metabolism booster signals, sending a fast, strong message to the brain to burn calories. This message is then sent to another part of the hypothalamus, where another peptide is produced and released. This stimulates the pituitary gland, which secretes a hormone that relays the message to the thyroid, the master of metabolism. Once activated, the thyroid gland then spreads word to the body's cells to increase energy production.

Keyword: Obesity; Hormones & Behavior
Link ID: 5886 - Posted: 06.24.2010