Tracy Staedter, Discovery News — An artificial cornea very similar to the real thing could return sight to people with damaged corneas. The lab-made tissue, developed by a team of researchers at Stanford University, imitates the properties of a natural cornea so closely that it may even fool the immune system of the recipient. The prosthetic device could reduce the need for human tissue, especially in developing countries where donors are more scarce. "Our goal is to really replace the need for human cornea tissue," said Christopher Ta, an assistant professor of ophthalmology and ophthalmology residency director at the Stanford University Medical Center. Ta leads the research with Curtis Frank, professor of chemical engineering. Between 10 and 12 million people worldwide have impaired sight because of damaged or diseased corneas — the clear tissue over the eye that protects it from dust and germs and focuses light onto the retina. Almost 45,000 patients worldwide receive corneal transplants each year. In the United States, such donations are plentiful and well organized by eye banks. © 2006 Discovery Communications Inc.

Keyword: Vision
Link ID: 9415 - Posted: 06.24.2010

UPTON, NY -- Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have found new clues to how the brain and the stomach interact with emotions to cause overeating and obesity. By looking at how the human brain responds to "fullness" messages sent to the brain by an implanted device that stimulates the stomach, the scientists have identified brain circuits that motivate the desire to overeat in the obese -- the same circuits that cause addicted individuals to crave drugs. The scientists have also verified that these circuits play a critical role in eating behaviors linked to soothing negative emotions. The study appears in the October 17, 2006 issue of the Proceedings of the National Academy of Sciences, published online in PNAS Early Edition the week of October 2. "This study opens new territory in understanding how the body and brain connect to each other, and how this connection is tied to obesity," said lead author Gene-Jack Wang of Brookhaven Lab's Center for Translational Neuroimaging. "We were able to simulate the process that takes place when the stomach is full, and for the first time we could see the pathway from the stomach to the brain that turns 'off' the brain's desire to continue eating." Wang and colleagues studied the brain metabolism of seven obese individuals who had gastric stimulators implanted for one to two years. The stimulator, an investigational device much like a pacemaker, provides low levels of electrical stimulation to the vagus nerve, causing the stomach to expand and produce peptides that send messages of "fullness" to the brain. The device has been shown to reduce the desire to eat.

Keyword: Obesity
Link ID: 9414 - Posted: 10.03.2006

Howard Hughes Medical Institute researchers have found that mutations in a single structural protein can determine whether an insect develops the highly organized, light-harvesting eye that flies have, or the optically simpler compound eye of a beetle or bee. In their experiments, the scientists showed that flies without this structural protein develop a more primitive eye. This outcome was reversed in the laboratory when researchers supplied the missing protein to a more primitive eye system, inducing it to “evolve” into the more advanced eye. “It’s not unusual to see alterations in regulatory proteins with a profound effect on form and function. This new finding, however, is unique because it illustrates how a change in a single structural protein can lead to such a spectacular change in form and function.” Charles S. Zuker These findings “help illustrate the beauty and power of evolution — how small changes can have such an incredible impact,” said HHMI investigator Charles S. Zuker, who led the study. Zuker and his colleagues at the University of California, San Diego reported their findings October 1, 2006, in an advance online publication in the journal Nature. The lead author of the paper was Andrew Zelhof. Robert Hardy and Ann Becker were co-authors. © 2006 Howard Hughes Medical Institute.

Keyword: Vision; Evolution
Link ID: 9413 - Posted: 06.24.2010

A gene that helps to stave off the effects of multiple sclerosis (MS) has been discovered by scientists. A Danish-UK team found that a known risk gene for MS, called DR2b, is always partnered by a twin gene - DR2a. The researchers, writing in the journal Nature, said DR2a tempers the effects of the risk gene and reduces the severity of MS symptoms. They believe in the future the gene's symptom-fighting features could be exploited for potential treatments. There are about 85,000 people with MS in the UK. The precise cause of the disease, in which the body's immune system attacks the central nervous system, is unknown, but a range of genetic and environmental factors are being explored. Two-thirds of MS sufferers carry the pair of DR2 genes, but carrying the genes does not necessarily mean a person will go on to develop MS. The researchers looked at mice that carried different combinations of the twin genes. They discovered the mice with just the risk gene, DR2b, had a form of multiple sclerosis with extremely aggressive symptoms. Those carrying both genes were less likely to get MS, and if they did, they had a milder form of the disease. The scientists said they believed the two genes were interacting. They said the risk gene, DR2b was "influencing" the immune system to attack the body, while the DR2a gene was counteracting this attack and dampening the effects. (C)BBC

Keyword: Multiple Sclerosis
Link ID: 9412 - Posted: 10.02.2006

ATLANTA -- Emory University researchers have found that giving progesterone to trauma victims shortly following brain injury appears to be safe and may reduce the risk of death and the degree of disability. The results of this study--the first clinical trial of its kind in the world--will be available online in the October issue of the peer-reviewed journal, Annals of Emergency Medicine, on October 2. Researchers say the next step will be to confirm their findings in a much larger group of traumatic brain injury (TBI) patients. "Progesterone treatment for TBI has been extensively studied in laboratory animals for more than 15 years, but this is the world's first use of progesterone to treat brain injury in humans," says Arthur Kellermann, MD, MPH, professor and chair of the Department of Emergency Medicine, Emory University School of Medicine and a co-author of the study. "Emory scientist Donald Stein was the first to discover that progesterone has neuroprotective effects, and much of the foundational work on progesterone for TBI was from his laboratory. Their results were so impressive, that we felt it was time to take this treatment to the bedside for testing in patients who had suffered a serious brain injury. We are grateful to the National Institute of Neurological Disorders and Stroke (a division of the National Institutes of Health) for their support of this work," says Kellermann. Approximately 1.5 to 2 million people in the U.S. sustain a TBI each year, leading to 50,000 deaths and 80,000 new cases of long-term disability. It is also a major cause of death and disability among children and military personnel.

Keyword: Brain Injury/Concussion; Hormones & Behavior
Link ID: 9411 - Posted: 10.02.2006

PITTSBURGH, Although drugs that target the brain's serotonin system are widely used to treat depression, the basic biological mechanism by which they help to alleviate symptoms is poorly understood. Now, new University of Pittsburgh research suggests these drugs work by acting on a specific serotonin receptor called the 5-HT1A autoreceptor, which the study's investigators found plays a key role in regulating the response of the amygdala. The findings, published in the journal Nature Neuroscience, also provide a model of how specific changes in 5-HT1A autoreceptors and associated amygdala reactivity may impact a person's risk for developing depression. Much like a rheostat, these serotonin receptors regulate the brain's emotional responses and may contribute to one's vulnerability for depression and other psychiatric disorders. The amygdala is a critical component of brain circuitry that processes clues from the environment about potential threats and generates appropriate behavioral and physiological responses – such as the "fight or flight" response – to these challenges. Research has indicated that depression and other mood disorders, such as anxiety, are associated with emotional brain circuitry problems involving the amygdala. The 5-HT1A autoreceptor is located on the surface of serotonin neurons, which are responsible for producing the serotonin neurotransmitter and delivering it to several areas of the brain, including the amygdala.

Keyword: Depression
Link ID: 9410 - Posted: 06.24.2010

Scientists have identified gene mutations responsible for a psychiatric disorder that causes people to compulsively pull their own hair. Trichotillomania is often accompanied by other symptoms, such as anxiety, depression, obsessive compulsive disorder or Tourette's syndrome. People with the disorder may have hair loss or bald patches, but often mask their habit. The Duke University study appears in the journal Molecular Psychiatry. The researchers focused on a gene called SLITKR1, as it had previously been linked to Tourette's. They found two mutant versions of the gene were more common in trichotillomania patients. The mutations were found to account for only a small percentage of cases. However, the team believe the findings are significant because they suggest the condition can have a biological basis. Lead researcher Dr Stephan Züchner said "Society still holds negative perceptions about psychiatric conditions such as trichotillomania. "But, if we can show they have a genetic origin, we can improve diagnosis, develop new therapies and reduce the stereotypes associated with mental illness." Currently, there is no specific treatment for trichotillomania, although it is sometimes successfully managed with drugs used for depression and anxiety disorders. The Duke team studied 44 families with one or more members who had trichotillomania. They found the key mutations were found in individuals with the condition, but not in unaffected family members. The SLITRK1 gene is involved in forming connections between brain cells. (C)BBC

Keyword: Emotions; Genes & Behavior
Link ID: 9409 - Posted: 09.30.2006

Bruce Bower The comfortably furnished room in a corner of the Johns Hopkins University School of Medicine in Baltimore seems an unlikely setting for spiritual transcendence. Yet one after another, volunteers last year entered the living room–like space, reclined on the couch, swallowed a pill, and opened themselves to a profound mystical journey lasting several hours. For many of them, the mundane certainty of being a skin-bounded person with an individual existence melted away. In its place arose a sense of merging with an ultimate reality where all things exist in a sacred, unified realm. Participants felt intense joy, peacefulness, and love during these experiences. At times, though, some became fearful, dreading unseen dangers. The pills that enabled these mystical excursions contained psilocybin, the active ingredient in so-called magic mushrooms that some societies have used for centuries in religious ceremonies. Psilocybin boosts transmission of the brain chemical serotonin, much as LSD and some other hallucinogenic drugs do. Johns Hopkins psychopharmacologist Roland R. Griffiths and his colleagues have taken psilocybin out of its traditional context and far from the black-light milieu of its hippie-era heyday. Griffiths' team is investigating the drug's reputed mind-expanding effects in a rigorous, scientific way with ordinary people. In the group's recent test, psilocybin frequently sparked temporary mystical makeovers in volunteers who didn't know what kind of pill they were taking. What's more, some of these participants reported long-lasting positive effects of their experiences. ©2006 Science Service.

Keyword: Drug Abuse
Link ID: 9408 - Posted: 06.24.2010

A new McGill University study that used thermal imaging technology for the first time ever to measure sexual arousal rates has turned the conventional wisdom that women become aroused more slowly than men on its head. "Comparing sexual arousal between men and women, we see that there is no difference in the amount of time it takes healthy young men and women to reach peak arousal," said Dr. Irv Binik, psychology professor and founder and director of the Sex and Couple Therapy Service of Royal Victoria Hospital, which is part of the McGill University Health Centre (MUHC). Thermal imaging, or thermography, is infrared imaging using thermographic cameras that detect radiation emitted by objects based on their temperature. Because of its usefulness in detecting warm objects in the dark, most people know it as the technology used in night vision goggles for military operations. Previously, sex researchers have measured arousal with instruments that require genital contact and manipulation. Binik focused thermographic cameras on his subjects' genitals while they watched a montage of material from pornography to horror movies to The Best of Mr. Bean to Canadian tourism travelogues to provide a base of control data. During the arousal experiment, the male and female subjects watched separate sexually explicit films procured from the Kinsey Institute and determined to be sexually arousing to specific genders. They watched the images through special video goggles to minimize distractions. © 2006 McGill University

Keyword: Sexual Behavior
Link ID: 9407 - Posted: 06.24.2010

Irritable Bowel Syndrome (IBS) is linked to low birth weights, according to a Norwegian study. Scientists have discovered that people born weighing less than 2.5kg (5.5lb) were at a greater risk of developing IBS than heavier babies. They believe this may be related to development of the digestive system. The study, published in the journal Gut, looked at 3,334 pairs of female and male identical and non-identical twins born between 1967 and 1979. They compared the recorded birth weight of the volunteers with whether they had gone on to suffer from IBS. Roughly one in 20 had suffered from IBS, a common and painful condition that has a wide range of symptoms, including regular abdominal pain, diarrhoea and constipation. Women were more likely to have IBS than men. The researchers found that those born weighing less than 2.5kg were more likely to have had IBS - although they were unable to quantify the exact size of the effect. For those born weighing less than 1.5kg, the difference was more marked: they were 2.5 times more likely to have had IBS when compared with those weighing above 2.5kg. Lead researcher Dr May-Bente Bengston, of the University of Oslo, said this was a "significantly higher risk". They also found that the twins with the low birth weight were more likely to develop IBS about eight years earlier than those weighing over 1.5kg. (C)BBC

Keyword: Stress
Link ID: 9406 - Posted: 09.28.2006

By RICHARD A. FRIEDMAN, M.D. What’s not to like about understanding and empathy? They’re comforting and reassuring. And they’re two things that make patients stick with their treatment, as any psychotherapist worth his or her salt can tell you. There is one little problem with psychotherapy when it relies on empathy and understanding alone, though: They often aren’t enough to get patients to change, let alone grow. Recently, I saw a 48-year-old professional single man in consultation who had been in therapy twice a week for six years. After telling me about his chronic depression, he went on to describe his life. “I had a miserable childhood,” he complained. “My father was an alcoholic who shouted all the time. My mother was a nonpresence and my brother checked out on drugs.” Then I asked him about what he did during his days. He was unemployed and supported in part by the neglectful parents whom he railed against. As is typical of narcissistic patients, he viewed his environment as having failed him and felt that he had not gotten the recognition in life that he deserved. “What do you hope to accomplish in therapy?” I asked him. “I just want to feel better and get rid of this depression.” “Tell me, how do you feel about your current therapist?” “Oh, she’s terrific. Warm, understanding and always available. But I don’t feel like I’m any better.” Copyright 2006 The New York Times Company

Keyword: Depression
Link ID: 9405 - Posted: 06.24.2010

By CLAUDIA DREIFUS When the neuroscientist Paul Greengard was named one of three winners of the 2000 Nobel Prize in Physiology or Medicine, he decided to use his award — almost $400,000 — to finance something new: the Pearl Meister Greengard Prize. “I hoped to bring more attention to the work of brilliant women scientists,” Dr. Greengard recently explained at his laboratory at Rockefeller University in New York. “Perhaps this will bring them further recognition and even a Nobel.” Dr. Greengard’s Nobel Prize, which was shared with Eric R. Kandel of Columbia University and Arvid Carlsson of Gothenberg University in Sweden, recognized his discoveries of how nerve cells communicate with one other. This year’s Nobel winners will be announced next week. Q. Why create the Pearl Meister Greengard Prize? A. There were two factors. One was the observation that there was still discrimination against women in science, even at the highest levels. On a personal level, I wanted to create something in honor of my mother, Pearl Meister, who died giving birth to me. Copyright 2006 The New York Times Company

Keyword: Depression
Link ID: 9404 - Posted: 06.24.2010

The term "blindsight" may sound like an oxymoron, but it's actually a bizarre effect in which people who have lost some of their vision from brain damage are still able to react to stimuli hidden in their blind spots. Researchers report that repeatedly stimulating the blind spots of partially blind people for several months can improve their ability to use blindsight in laboratory tests, suggesting that larger trials of the technique are warranted. Stroke, trauma or surgery can cause so-called cortical blindness by knocking out a portion of the visual cortex, the part of the brain that receives input from the eyes. Blindsight is thought to occur because the brain is capable of rerouting the visual information that the eyes are still receiving. Examples of the effect include being able to guess the color, motion and even emotional expression of visual stimuli placed in the blind spot at better than chance rates. Some groups have tried to identify improvements in blindsight after repeated stimulations, but such studies have generally involved introducing stimuli near the edges of the blind spot, which leaves open the possibility that subjects could have skewed the data by shifting their gaze. Hoping to eliminate this source of uncertainty, vision researcher Arash Sahraie of the University of Aberdeen in Scotland and his colleagues asked 12 cortically blind people to practice their blindsight for stimuli smack in the middle of their blind spots. Daily for three months, participants using home computers repeatedly guessed which of two stimuli was presented to them first--either a flickering circular field of black and white lines, designed to maximally stimulate their cortices, or a gray dot. © 1996-2006 Scientific American, Inc.

Keyword: Vision
Link ID: 9403 - Posted: 06.24.2010

by Stephanie Bird Imagine two scenarios. In the first, you are driving down the street and are suddenly overcome by a fit of sneezing. You veer off to the right, and by the time you come to a stop, you realize, to your horror, that you have hit a young woman walking on the sidewalk. She is pinned against a brick wall and, despite emergency treatment, will be paralyzed below the waist for life. In the second scenario, you are driving a pickup truck on a fine summer morning when you suddenly notice a bee buzzing around inside. You are frightened because you think you might be allergic to bee stings, and while trying to kill the bee with a handy newspaper, you swerve into oncoming traffic, hitting a small car head-on. The driver, a young father of two, is killed. Are you morally responsible in either of these cases (both of which actually occurred), and should you be held legally responsible? In each case, you can honestly say you didn’t mean to cause harm, and it makes a difference that there was neither conscious nor unconscious intent. Still, could you have foreseen the potential consequences of your distraction? We expect people to exercise self-control. We all know that it is difficult but not impossible to stifle a sneeze; you might do so in a classroom, for instance. We could argue that we have even more control over how we respond to our fears than we do to our impulses. Shouldn’t we be expected, then, to not allow ourselves to be distracted by fear of a bee sting when engaged in something as risky as driving? © 2002 Science & Spirit Magazine.

Keyword: Emotions
Link ID: 9402 - Posted: 06.24.2010

(SACRAMENTO, Calif.) -- A man's stereotypical self-image as the "strong, silent type" and the stigma of depression are major reasons why older men are less likely than women to be referred to studies of depression, to seek treatment for depression, and to recognize and express symptoms of depression, according to clinicians and recruiters interviewed for a new study from the UC Davis Department of Psychiatry and Behavioral Sciences. The study provides some of the strongest evidence to date that depressed older men are less likely than women to receive treatment for their depression, underscoring the importance of these barriers. Among some older men, the study found, traditional views of masculinity and the stigma associated with mental illness lead to a tendency to reject a diagnosis of depression, and to conceal or mask symptoms of the condition. Authored by UC Davis associate professor of psychiatry professor Ladson Hinton, the study appears in the October 2006 edition of the American Journal of Geriatric Psychiatry. The study contributes further evidence to gender disparities in depression care documented in previous studies, and identifies reasons for these disparities. The findings are important in the arena of public health because of depression's association with suicide in older adults. Older men have higher rates of completed suicide: 31.8 per 100,000 in men age 65 and older, compared with 4.1 per 100,000 in older women. The reasons for gender disparities in depression care among older adults are poorly understood.

Keyword: Depression
Link ID: 9401 - Posted: 09.28.2006

John Pickrell The queens of bees, ants and wasps that indulge in the most promiscuous and lengthy sex marathons produce the healthiest colonies, a new study reveals. Honeybee queens that mated with multiple drones were shown to foster bee hives with wider genetic variation. This variation meant they were much better able to fend off a debilitating disease, researchers found. For many social insect queens, mating is a costly activity. In honeybees, for example, it involves her flying many kilometres from the hive to rendezvous sites with male drones – the longer she stays to mate, the more precious energy she expends, and the greater the chance there is that she will be devoured by predators. This has made experts wonder why the queens of some species of social insects indulge in multiple sexual encounters, while others make do with a single male. Ideas include that the resulting genetic variation could help improve the division of labour in a colony, or that multiple mating might simply be a strategy to collect more sperm. But perhaps the most convincing theory is that queens that take many lovers produce colonies that are better protected against disease. "Insects living very closely in nutrient-rich environments are hotbeds for micro-organisms – they need mechanisms to protect against disease," says apiculturalist (bee expert) David Tarpy at North Carolina State University in Raleigh, US. © Copyright Reed Business Information Ltd

Keyword: Sexual Behavior; Evolution
Link ID: 9400 - Posted: 06.24.2010

By Patricia McAdams Fetuses of mothers who show high rates of depression, anxiety and stress weigh less and are smaller than average at midterm, according to a recent study from the University of Miami School of Medicine. Psychobiologist Miguel Diego and colleagues found that the stress hormone cortisol seems to be one potential mechanism for transmitting a mother's stress to her unborn baby. "Maternal distress is accompanied by biochemical changes, such as increased cortisol, that can both directly and indirectly affect the fetus," Diego said. "Cortisol can directly cross through the placenta into the fetus, which could affect fetal development." The study, published in the September-October issue of Psychosomatic Medicine, may shed light on previous findings that women with prenatal depression, anxiety or stress are more likely to deliver premature and low-birth-weight babies. Cortisol "can also affect the mother's vascular function, thereby reducing blood flow to the fetus, which could affect fetal growth by diminishing the amount of oxygen and nutrients that are delivered," Diego said. © 2006 The Washington Post Company

Keyword: Stress; Development of the Brain
Link ID: 9399 - Posted: 06.24.2010

By JANE E. BRODY Conversations with my elderly aunt alternate between being comical and frustrating. I might say to her, “My grandsons are now swimming like fish,” and she will reply, “My friend’s dog died yesterday.” If I should ask, “What is your granddaughter doing this summer?” she is likely to reply with something like, “I went shopping in Brooklyn yesterday.” Though her mind remains razor sharp and she maintains an independent life in her late 80’s, her hearing is so poor that most people soon give up trying to engage her in conversation, unless they happen to enjoy such non sequiturs. But though family members have been urging her for years to get a hearing aid, she has refused, saying, “They’re too much trouble,” or that a friend had one and didn’t like it (although this friend wears hers every day). My aunt is one of 31.5 million Americans who suffer from hearing loss. They include a third of Americans over 60 and up to half of those over 75, most of whom have age-related hearing loss, a condition known medically as presbycusis. Hearing loss is the third most common chronic condition among older Americans, after hypertension and arthritis. Hearing difficulties in older people can have serious consequences, including social isolation, functional decline and depression. Hearing loss can also impair memory and cognitive function, according to a study by neuroscientists at Brandeis University. Copyright 2006 The New York Times Company

Keyword: Hearing
Link ID: 9398 - Posted: 06.24.2010

Jacquie van Santen Genes influence how you learn to read and spell (Image: iStockphoto) The genes involved in learning to sound out words are different from the ones involved in learning to recognise words by sight, according to an Australian study. The finding, published online in the journal Reading and Writing, adds fuel to the debate about the best way of teaching children to read. There are two particular skills that children need to learn if they are going to be good readers. The first is the sounding out process, known as phonics. The other skill is being able to recognise familiar words pretty much by sight. This helps when they read words such as 'yacht' that don't follow the phonics rule. Researchers including Associate Professor Anne Castles, from the University of Melbourne, tested different genetic models for reading and spelling in 691 sets of identical and non-identical twins to determine to what extent these skills are genetically based. Twins are ideal for this type of research because identical twins are more similar genetically than non-identical twins. ©2006 ABC

Keyword: Language; Genes & Behavior
Link ID: 9397 - Posted: 06.24.2010

By ERIKA KINETZ Hysteria is a 4,000-year-old diagnosis that has been applied to no mean parade of witches, saints and, of course, Anna O. But over the last 50 years, the word has been spoken less and less. The disappearance of hysteria has been heralded at least since the 1960’s. What had been a Victorian catch-all splintered into many different diagnoses. Hysteria seemed to be a vanished 19th-century extravagance useful for literary analysis but surely out of place in the serious reaches of contemporary science. The word itself seems murky, more than a little misogynistic and all too indebted to the theorizing of the now-unfashionable Freud. More than one doctor has called it “the diagnosis that dare not speak its name.” Nor has brain science paid the diagnosis much attention. For much of the 20th century, the search for a neurological basis for hysteria was ignored. The growth of the ability to capture images of the brain in action has begun to change that situation. Functional neuroimaging technologies like single photon emission computerized tomography, or SPECT, and positron emission tomography, or PET, now enable scientists to monitor changes in brain activity. And although the brain mechanisms behind hysterical illness are still not fully understood, new studies have started to bring the mind back into the body, by identifying the physical evidence of one of the most elusive, controversial and enduring illnesses. Copyright 2006 The New York Times Company

Keyword: Emotions
Link ID: 9396 - Posted: 06.24.2010