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Ranitidine, a widely used substance used as an antihistaminic drug against gastric ulcers, may become a new treatment for cerebral ischemia caused by craneoencephalic infarcts or traumatisms, the third leading cause of deaths in industrialised countries. In experiments with a model of cerebral ischemia using rats, a team from the Institute of Neurosciences of the Universitat Auṭnoma de Barcelona (Spain) has observed how the presence of ranitidine reduces neuronal death by a quarter. The substance reaches its maximum effect six hours after the lesion has occurred, which will facilitate treatment in real cases with humans. The scientists of the Institute of Neurosciences at the UAB have studied ranitidine's effects on an experimental model using neurons from rats' brains. The cells underwent a lack of oxygen and glucose analogous to that which they suffer, within the brain, when there is a lack of blood flow (what happens when there is a cerebral ischemia) caused by an infarct or a traumatism. When a lesion of this type occurs, the cells either die directly or, in many cases, they becomes victims of a slow programmed death called apoptosis, a kind of "suicide" at a cellular level.
Keyword: Stroke; Apoptosis
Link ID: 6597 - Posted: 12.16.2004
In experiments with fruit flies, Johns Hopkins researchers have found that blindness induced by constant light results directly from the loss of a key light-detecting protein, rather than from the overall death of cells in the retina, which in humans is a light-sensitive tissue at the back of the eye. The research, reported in the Dec. 14 issue of Current Biology, overturns the long-standing belief that blindness from chronic light exposure is a direct result of overall retinal degeneration and cell death. Although many animals, and presumably humans, lose both their retinal cells and vision after exposure to low levels of light for long periods, the relationship between exposure and blindness had been poorly understood. In the Hopkins experiments, flies whose light-detecting protein rhodopsin was engineered to resist destruction retained their vision twice as long as normal flies, although over time they developed blindness due to delayed decay of rhodopsin. The researchers measured vision damage indirectly by measuring loss of the electrical signals normally initiated by rhodopsin when exposed to light. "Everyone assumed that the blindness caused by chronic light exposure was an effect of the degeneration and loss of the retinal cells, but our experiments show these are two distinct events caused by two distinct processes," says Craig Montell, Ph.D., professor of biological chemistry in Hopkins' Institute for Basic Biomedical Sciences. "Understanding how degradation of rhodopsin and other visual proteins contributes to vision loss may help us in the future to reduce the severity of blindness in rare people susceptible to chronic exposure to light."
Keyword: Vision
Link ID: 6596 - Posted: 12.16.2004
Perhaps the Beanie Baby craze wasn't so weird after all. Most people have a collection of some kind at some point in their lives. Indeed, historical studies show that acquiring and retaining objects, even when they are not necessary for survival, is not only nearly universal, but also has been part of human behavior since the earliest human societies. Yet despite the ubiquitous nature of this trait, very little is known about what drives humans to collect. By studying patients who developed abnormal hoarding behavior following brain injury, neurology researchers in the University of Iowa Roy J. and Lucille A Carver College of Medicine have identified an area in the prefrontal cortex that appears to control collecting behavior. The findings suggest that damage to the right mesial prefrontal cortex causes abnormal hoarding behavior by releasing the primitive hoarding urge from its normal restraints. The study was published online in the Nov. 17 Advance Access issue of the journal Brain. Hoarding behavior is common among animals; around 70 species hoard and mostly they hoard food, which makes sense from a survival standpoint. Studies of hoarding behavior in rodents have shown that collecting is driven by certain primitive structures deep in the brain and most mammals, including humans, share these subcortical regions.
Keyword: OCD - Obsessive Compulsive Disorder
Link ID: 6595 - Posted: 12.16.2004
ATLANTA -- Scientists with the Center for Behavioral Neuroscience, a research consortium based at Georgia State University, have for the first time used a form of magnetic resonance imaging to reveal anatomical features of the nervous system in a live crayfish, a crustacean whose brain measures only 3 millimeters wide. The technique, which is reported and highlighted in an accompanying commentary in the Dec. 15 issue of The Journal of Experimental Biology, provides a powerful new tool for understanding the neurobiology of behavior in invertebrate animal models. Conventional MRI technology employs high-intensity magnetic fields to excite protons in the water molecules of soft tissue. Scanners detect the excitation and image cross-sectional slices of an organ, such as the brain. To image a live crayfish, whose physiology does not normally respond to magnetic fields, CBN researchers injected manganese, a contrast-enhancing agent that crayfish cells absorb, through a long tube into its circulatory system. The infusion took place while the animal was positioned inside the MRI scanner.
Keyword: Brain imaging
Link ID: 6594 - Posted: 12.16.2004
Pharaoh ants use an appreciation of geometry to find their way home. Worker pharaoh ants travel to and from their colony along a series of branching paths scented with pheromones. But until now it was unclear how the ants knew which branch would lead them home. Duncan Jackson and his colleagues at the University of Sheffield, UK, noticed that various species of leafcutter and pharaoh ants - Monomorium pharaonis - lay trails radiating out from the nest that fork at an angle of 50° to 60°. When a returning ant reaches a fork in the trail, it usually takes the path which deviates least. In other words, it will change direction slightly to the right or left but will not make an acute turn back on itself. This means it always takes the path that leads back to the colony.
Keyword: Chemical Senses (Smell & Taste)
Link ID: 6593 - Posted: 12.16.2004
Helen Pearson The infectious proteins called prions that cause the human form of mad cow disease may hitch into the body on the back of another meat protein, US researchers have shown. The finding may help to explain how the rogue prions jump between species. Disease-causing prions are thought to have passed into people when they ate beef from infected cattle, triggering the brain wasting condition called new-variant Creutzfeldt-Jakob disease, or vCJD. But researchers have not been sure exactly how prions enter the body. To find out, Neena Singh and her team at Case Western Reserve University in Cleveland, Ohio, mimicked the process of eating and digesting infected meat. They mashed up brain tissue that contained prions from patients who had a form of Creutzfeldt-Jakob disease. They then exposed it to a range of harsh digestive enzymes from the mouth, stomach and intestine, which normally break proteins into pieces. Prions, which are known to be enormously tough, escape this attack almost unscathed, they showed, as does a second type of protein called ferritin, which stores iron and is abundant in meat. The two proteins seem to stick together, they report in the Journal of Neuroscience1. ©2004 Nature Publishing Group
Keyword: Prions
Link ID: 6592 - Posted: 06.24.2010
Using a precisely targeted laser, researchers have snipped apart a single neuron in the roundworm C. elegans — an achievement that opens a new avenue for studying nerve regeneration in this genetically manipulable animal. Indeed, their initial studies have demonstrated that the severed nerves of worms are capable of regenerating and regaining full function. According to the researchers, studying nerve regeneration in the worm could provide answers to questions that are not accessible currently by doing experiments in more complex animals, including mice and zebrafish. “Until now there has been little study of nerve regeneration using genetic methodology, because most studies have been done on higher vertebrate organisms.” Yishi Jin A research team that included Yishi Jin, a Howard Hughes Medical Institute investigator at the University of California, Santa Cruz (UCSC), Andrew Chisholm, also of UCSC, and Adela Ben-Yakar, who was at Stanford University and is now at the University of Texas at Austin, reported its achievement in the December 16, 2004, issue of the journal Nature. Other co-authors are from Stanford University and UCSC. © 2004 Howard Hughes Medical Institute
Keyword: Regeneration
Link ID: 6591 - Posted: 06.24.2010
Marine biologists have confirmed sharks can detect changes in magnetic fields. This ability has long been suspected by researchers who have observed the fish migrating huge distances in the ocean along straight lines. A Hawaii University team has trained captive sharks to swim over targets in their tank whenever an artificial magnetic field is activated. The new study, by Dr Carl Meyer and colleagues, is reported in Interface, a journal of the UK's Royal Society. "This significant advance in demonstrating the existence of a 'compass' sense should now make it possible to investigate exactly how this sense works and how sensitive sharks are to the Earth's magnetic field," the team tells Interface. The Hawaii group used six sandbar sharks and one scalloped hammerhead in their research. They kept the animals in a 7m-diameter tank. The fish were trained to associate the presence of food in a 1.5m by 1.5m target area on the enclosure floor with the switching on of a magnetic field, derived from a copper coil surrounding the tank In a series of trials, the field was then activated at random times and the fish were seen to move on the feeding zone even when there was no food present, proving the existence of their "compass". "Activating the artificial field produced an immediate response in the conditioned sharks," the team says. "They changed from swimming steadily around the perimeter of the tank to swimming faster, turning rapidly and converging on the target in anticipation of a food reward." Tiger sharks, blue sharks and scalloped hammerhead sharks are all known to swim in straight lines for long periods across hundreds of kilometres of open ocean, and then later orient themselves to underwater mountains, or seamounts, where geomagnetic anomalies exist. Scientists want to understand how sharks are able to detect magnetic fields. Other animals that do it, such as trout and pigeons, possess the iron mineral magnetite in their bodies. (C)BBC
Keyword: Miscellaneous
Link ID: 6590 - Posted: 12.15.2004
The development of a laboratory model for a rare, inherited form of blindness holds promise that scientists might one day be able to test new treatments to prevent or cure this devastating disease of the retina. This finding, from investigators at St. Jude Children's Research Hospital and Columbia University, will be published in the Dec. 20 issue of Molecular Brain Research (MBR). The model for this disease, called Leber congenital amaurosis (LCA), is especially important because no treatments are currently available to prevent it. There are not enough patients to enroll in large clinical trials to test new prevention treatments; therefore, any potential new therapy must have a high probability of working. This is especially the case with LCA. Diseases with such a limited patient population discourage the expensive commercial research and development needed to find an effective treatment for it, according to Michael A. Dyer, Ph.D., assistant member of St. Jude Developmental Neurobiology. Dyer is first author of the MBR report. The investigators are now using the model to develop a gene therapy to prevent this form of blindness. "The development of this model reflects an important goal at St. Jude of finding cures for rare devastating childhood diseases beyond cancer," Dyer said.
Keyword: Vision; Genes & Behavior
Link ID: 6589 - Posted: 12.15.2004
By Kelly Hearn, AlterNet. For Gene Haislip, a former official of the U.S. Drug Enforcement Agency, the perennial debate over Ritalin, the stimulant commonly prescribed for children with "attention deficit hyperactivity disorder (ADHD)," is an aching reminder of a moral battle he fought – and lost – to big drug companies. For 17 years, the now retired director of the DEA´s Office of Diversion Control set production quotas for controlled substances like methylphenidate (MPH), the federally restricted stimulant commonly known as Ritalin. During that time, he fought hard to raise public awareness about over-prescribing of stimulants to children, about the drug's high rate of street diversion, and about its long-term health impact on young patients. "This affects the most sensitive part of our population," says Haislip, now a consultant for drug companies on issues of compliance to federal law. "When I was at the DEA, we created awareness about this issue. But the bottom line is we didn't succeed in changing the situation because this – prescribing methylphenidate, for example – is spiraling. "A few individuals in government expressing concern can't equal the marketing power of large companies," he adds. "I have doubts that the truth is driving this issue. It seems that market forces and money is behind it." © 2004 Independent Media Institute.
Keyword: ADHD; Drug Abuse
Link ID: 6588 - Posted: 06.24.2010
A mutant gene that starves the brain of serotonin, a mood-regulating chemical messenger, has been discovered and found to be 10 times more prevalent in depressed patients than in control subjects, report researchers funded by the National Institutes of Health's National Institute of Mental Health (NIMH) and National Heart Lung and Blood Institute (NHLBI). Patients with the mutation failed to respond well to the most commonly prescribed class of antidepressant medications, which work via serotonin, suggesting that the mutation may underlie a treatment-resistant subtype of the illness. The mutant gene codes for the brain enzyme, tryptophan hydroxylase-2, that makes serotonin, and results in 80 percent less of the neurotransmitter. It was carried by nine of 87 depressed patients, three of 219 healthy controls and none of 60 bipolar disorder patients. Drs. Marc Caron, Xiaodong Zhang and colleagues at Duke Unversity announced their findings in the January 2005 Neuron, published online in mid-December. "If confirmed, this discovery could lead to a genetic test for vulnerability to depression and a way to predict which patients might respond best to serotonin-selective antidepressants," noted NIMH Director Thomas Insel, M.D.
Keyword: Depression; Genes & Behavior
Link ID: 6587 - Posted: 12.15.2004
Galanin is one of several neuropeptides known to increase food intake. Previous findings have suggested that galanin may also be involved in alcohol consumption and/or the motivation to drink alcohol beverages. Most recently, researchers have discovered that giving galanin microinjections to rodents can increase their voluntary alcohol intake. Their findings are published in the December issue of Alcoholism: Clinical & Experimental Research. "Galanin's well-known effects of increasing food intake, especially the intake of fat-rich diets, was one of the early reasons we investigated it," said Michael J. Lewis, a senior fellow working with Dr. Bart Hoebel in his laboratory in the Department of Psychology at Princeton University and Sarah Leibowitz at Rockefeller University, and corresponding author for the study. "Alcohol is the only drug of abuse that can also qualify as a calorie-rich food, and it undoubtedly has important interactions with systems that control food intake and nutrition." Lewis added that alcohol, galanin and food intake have another area of commonality: all are stimulants of the neurotransmitter dopamine, which has been linked by numerous studies to the rewarding effects and "high" produced by potent drugs of abuse such as nicotine, cocaine and heroin.
Keyword: Drug Abuse; Obesity
Link ID: 6586 - Posted: 12.15.2004
People who have migraines are twice as likely to have a stroke as others, researchers estimate. Experts in Canada and the US looked at 14 studies that had shown a link to quantify the exact risk involved. Migraines roughly doubled the stroke risk, while migraines with 'auras' more so than those without interruptions to the sufferers' vision. Women with migraines who were on the oral contraceptive pill appeared to be at particular risk, reserach found. The increased risk of stroke is probably down to the reduced blood flow to the brain which usually occurs in a migraine, the researchers believe. The studies looked at by Dr Ali Samii, neurologist at the University of Washington, and his colleagues, suggest the risk of stroke for migraine sufferers is 2.16 times that for non-sufferers. Those who have migraines with auras are 2.27 times as likely to suffer a stroke and in those with migraines without auras the risk is increased 1.86 times. Three of the studies showed that women migraine sufferers who were also taking oral contraceptives were up to eight times more likely to suffer a stroke than those not taking the pill. The researchers said the latter results were slightly at odds with other studies, which suggest a smaller degree of increased risk for such women - about double. Therefore, they say much more research should be carried out to establish what the risk is. "Given that the use of oral contraceptives is prevalent among young women, the potential risk of stroke among women with migraine who are also users of oral contraceptives must be further investigated," they said in their paper which is due to be published in the British Medical Journal. (C)BBC
Keyword: Stroke; Pain & Touch
Link ID: 6585 - Posted: 12.14.2004
Eating a low calorie diet may help to reduce the risk of Parkinson's disease, research suggests. A team from the US National Institute on Ageing found a long-term reduction in caloric intake protects rhesus monkeys from developing the disease. They believe restricting caloric intake switches on mechanisms which protect the brain cells lost in people diagnosed with Parkinson's. Details are published in Proceedings of the National Academy of Sciences. A number of studies have suggested the normal ageing process causes a loss of brain cells that produce a key chemical called dopamine in an area of the brain called the substantia nigra. It is thought that Parkinson's disease speeds up the loss of these cells, leading to the problems with movement associated with the condition. Limiting the number of calories in the diet has been shown to have a powerful effect in slowing down the ageing process. The US team decided to examine whether it could also prevent the development of Parkinson's symptoms in monkeys. For six months monkeys received a diet with 30% fewer calories than the control diet. At that point, the monkeys were injected with a toxin that causes a Parkinson-like disease. The calorie-restricted monkeys showed better control over their movement, and higher levels of dopamine in their brains. They also had higher levels of a growth factor, GDNF, which the researchers believe may protect brain cells from destruction. The researchers say their work suggests that long-term caloric restriction may reduce the risk of developing Parkinson's by turning on production of this protective growth factor. (C)BBC
Keyword: Parkinsons; Obesity
Link ID: 6584 - Posted: 12.14.2004
By ANAHAD O'CONNOR Looking back, Denise Watkins is convinced a sore throat disabled her son one year ago. His bizarre obsessions emerged not long after, first the constant nightmares about snakes and alligators, then the relentless hand washing that left his skin raw and chapped. Mrs. Watkins, who lives in Lakeland, Fla., was told that her son, Will, had obsessive-compulsive disorder. But it seemed odd, Ms. Watkins thought. Will was only 5 years old, and his illness seemed to burst out of nowhere. "In a matter of weeks," she said, "this was a totally different child." Then one day, buried on a Web site about mental illness, her husband noticed a small "blip" on children who develop a sudden, severe form of obsessive-compulsive disorder after a bout of strep throat. Mrs. Watkins read the description, decided that Will fit the pattern, and thus became part of a small but growing number of parents who blame a common bacterial infection for the psychiatric illness of a son or daughter. About one child in 1,000 may be afflicted, but some experts say the number is higher if milder cases that escape notice are included. The condition is known as Pandas, or pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection, and scientists know so little about it that some question whether it even exists. Copyright 2004 The New York Times Company
Keyword: Emotions
Link ID: 6583 - Posted: 12.14.2004
By ANAHAD O'CONNOR SEATTLE - Sitting in a small evaluation room at the University of Washington, apprehension written on her face, Christa Zamora turned her eyes toward her son Connor and contemplated his future. A talkative and animated 2-year-old, Connor appears normal, Ms. Zamora said, but it is too soon to be certain. Doctors diagnosed autism in her older son, Cameron, just before he turned 3. And with Connor, who is also at risk for developing the devastating neurological disorder, which runs in families, she has decided to be proactive, enrolling him in an early diagnosis study for children as young as 16 months. "I'm very concerned," said Ms. Zamora, who is also worried about her third child, a boy due in February. "Connor seems to be past the danger zone. But Cameron repeats himself a lot, and sometimes I see Connor doing the very same things." Across the country, thousands of toddlers like Connor are joining studies that could signal new hope for a baffling childhood disorder. Copyright 2004 The New York Times Company
Keyword: Autism
Link ID: 6582 - Posted: 12.14.2004
Every year, millions of people try to look younger by taking injections of Botox, a prescription drug that gets rid of facial wrinkles by temporarily paralyzing muscles in the forehead. Although best known as a cosmetic procedure, Botox injections also have been approved by the Food and Drug Administration (FDA) to treat uncontrolled blinking (blepharospasm), lazy eye (strabismus), involuntary muscle contractions in the neck (cervical dystonia) and acute underarm sweating (severe primary axillary hyperhidrosis). Botox users might be surprised to learn that they're actually receiving minute injections of a bacterial neurotoxin called botulinum, one of the most poisonous substances known. Exposure to large amounts of botulinum bacteria can cause a paralytic, sometimes-fatal disease called botulism. Last month, several Floridians were hospitalized with botulism after receiving injections of an anti-wrinkle treatment that authorities suspect was a cheap, non-FDA-approved imitation of Botox. The botulinum toxin works by invading nerve cells, where it releases an enzyme that prevents muscle contraction. In recent years, scientists have determined that the enzyme binds to specific sites on proteins called SNAREs, which form a complex in the synapse between nerve and muscle cells. Without SNAREs, nerves cannot release the chemical signals that tell muscle cells to contract, and paralysis results.
Keyword: Neurotoxins
Link ID: 6581 - Posted: 12.14.2004
The "Grand Theft Auto" series of video games is one of the industry's most popular, and also one of the most controversial. This holiday season brings another sequal: "Grand Theft Auto: San Andreas." In it, players control a character who participates in gangland wars, murders police officers and assaults prostitites. The game is expected to sell well enough to rival a blockbuster movie. "In this game, you play the part of a psychopath, basically," says Douglas Gentile, a psychologist at Iowa State University. "You run around the street, you can run down pedestrians with the car, you can do carjackings, you can do drive-by shootings, you can run down to the red-light district, pick up a prostitute, have sex with her in your car, and then kill her to get your money back. Most parents are unaware that this most popular game in the country has such very adult themes in it." Gentile is also research director for the National Institute on Media and the Family, a group which recently held a press conference on Capitol Hill along with concerned lawmakers to warn parents about the content of today's games. Perhaps even more controversial this year than "Grand Theft Auto" is "JFK: Reloaded," in which you recreate the assassination of John F. Kennedy. © ScienCentral, 2000- 2004
Keyword: Aggression
Link ID: 6580 - Posted: 06.24.2010
Bird songs have inspired musicians and poets alike. Now, researchers looking into what inspires young birds to learn them are finding they use a variety of methods to copy the adults' songs. Fernando Nottebohm, an animal behavior scientist at The Rockefeller University in New York City, and his postdoctoral associate Wan-Chun Liu observed and recorded groups of juvenile zebra finches learning to sing. They used a computer program developed at Rockefeller to analyze similarities in the singing patterns, and found that the birds tended to imitate sounds in two ways—by repeating an early syllable, or by approximating the whole song at once. Both styles appear to work well. Liu notes, "whatever strategy they are using, eventually they can produce a very good imitation from their father." Nottebohm explains the difference: "Imagine a series of repetitions of a same vowel—A A A A A A A A. Then the second A is gradually turned into an R, the third one into a T, the fourth one into an I, the fifth one into an S, the sixth one into a T, the seventh one into and I and the last one into a C. When you are done, and the changes are slow and proceed at different paces for each position in this eight letter run; A A A A A A A A has become A R T I S T I C. That, in a nutshell, is what the birds that follow the 'repetition strategy' end up doing. Those that work starting more globally produce a slurred, almost unrecognizable initial version of ARTISTIC, of about the right length, and then they start to improve each part of that statement, also gradually and a various speeds, ending up, like the colleagues, with the same statement." © ScienCentral, 2000- 2004.
Keyword: Language; Sexual Behavior
Link ID: 6579 - Posted: 06.24.2010
Of all the world's animals, only humans, some kinds of birds and perhaps some porpoises and whales learn the sounds they use to communicate with each other through a process of listening, imitation and practice. For the rest, including nonhuman primates, these sounds develop normally in the absence of external models. Now Rockefeller University scientists have found that zebra finches, songbirds native to Australia, use infant-like strategies to learn their song. Some finches focus on perfecting individual song components, referred to as "syllables," while others practice longer patterns called motifs. Which strategy they choose, or what combination of strategies, seems to depend on what their siblings are doing. In time, all are able to sing the same adult song. The results, reported in the December 13 online issue of Proceedings of the National Academy of Sciences, are the first to show a social influence on how birds learn their song by analyzing song-learning with birds kept in family groups rather than in isolation chambers. The Rockefeller team also shows for the first time that individual birds, of the same species, can follow different strategies to get to the same end point of singing the adult song. Until now, scientists thought that the vocal learning process in birds was mainly a matter of filling in details in a pre-existing developmental program. If so, then this program is, in zebra finches, a very flexible one.
Keyword: Sexual Behavior; Language
Link ID: 6578 - Posted: 12.14.2004