Peter Weiss In a Los Angeles laboratory, researchers have let loose scores of what amount to living micromachines. Dwarfed by a comma, each tiny device consists of an arch of gold coated along its inner surface with a sheath of cardiac muscle grown from rat cells. With each of the muscle bundles' automatic cycles of contraction and relaxation, the device takes a step. Viewed under a microscope, "they move very fast," says bioengineer Jianzhong Xi of the University of California, Los Angeles (UCLA). "The first time I saw that, it was kind of scary." Xi and his UCLA colleagues Jacob J. Schmidt and Carlo D. Montemagno describe their musclebots in the February Nature Materials. Microcontraptions of this sort may someday make pinpoint deliveries of drugs to cells or shuttle minuscule components during the manufacture of other itsy machines or structures, Xi says. Variations on the same design could lead to muscle-driven power supplies for microdevices or laboratory test beds for studying properties of muscle tissue. Because the musclebot is both minuscule and designed to operate in body fluids, "this is the Fantastic Voyage kind of thing" that might someday roam the bloodstream and carry out on-the-spot surgery or disease treatments, comments physicist James Castracane of the State University of New York in Albany. Copyright ©2005 Science Service.

Keyword: Muscles
Link ID: 6733 - Posted: 06.24.2010

Reviewed by Elizabeth Svoboda Alex, an African Grey parrot, knows what he wants and intends to get it. "Want nut!" he squawks at his scientist owner, Irene Pepperberg. Before he can get his reward, though, he has to perform a task. "What matter?" Pepperberg asks Alex, showing him a cloth ball. "Wool," he answers correctly -- he can also identify wood, plastic, metal and paper -- then munches on his requested treat. Unlike some parrots with a vast capacity for mimicry, Alex has a "vocabulary" of only about 100 words, but he has an important cognitive advantage: He actually seems to know what he's talking about. Watching Alex and Pepperberg interact, it's easy to conclude that the parrot, like Hugh Lofting's Gub-Gub the pig or Jip the dog, has mastered the fundamentals of human language. Not so fast, says Stephen R. Anderson, a professor of linguistics and cognitive science at Yale University. Alex and animals like him -- such as Koko, the famous gorilla who has learned more than 1,000 hand signs from her keepers -- are remarkable, he concedes. Nevertheless, their feats don't prove that the fictional Dr. Dolittle was right in his belief that animals can talk. Why can't we say that Alex and Koko, who draw upon learned sets of symbols to communicate, are using language? Simple, Anderson answers in "Dr. Dolittle's Delusion": They lack syntax. In our amazement that birds and gorillas can correctly refer to individual objects, we lose sight of how intricate linguistic structure is and how unequipped animals are to grasp it. Through years of training, Alex has learned to apply English words to things in his environment ("wool" for the cloth ball, "nut" for his beloved cashews), but no reward can coax him to string these expressions into a meaningful new combination of words, as humans can. Likewise, although Koko scores 60 percent correct in tests in which she gives a sign for each object presented to her, her attempts to combine signs result in magnetic-poetry-like hodgepodge such as "You Koko love knee do." ©2005 San Francisco Chronicle

Keyword: Language
Link ID: 6732 - Posted: 06.24.2010

St. Louis, -- Brain cells in a mouse model of Alzheimer's disease have surprised scientists with their ability to recuperate after the disorder's characteristic brain plaques are removed. Researchers at Washington University School of Medicine in St. Louis injected mice with an antibody for a key component of brain plaques, the amyloid beta (Abeta) peptide. In areas of the brain where antibodies cleared plaques, many of the swellings previously observed on nerve cell branches rapidly disappeared. "These swellings represent structural damage that seemed to be well established and stable, but clearing out the plaques often led to rapid recovery of normal structure over a few days," says senior author David H. Holtzman, M.D., the Charlotte and Paul Hagemann Professor and head of the Department of Neurology. "This provides confirmation of the potential benefits of plaque-clearing treatments and also gets us rethinking our theories on how plaques cause nerve cell damage." Prior to the experiment, Holtzman and some other scientists had regarded plaque damage to nerve cells as a fait accompli--something that the plaques only needed to inflict on nerve cells once. According to Holtzman, the new results suggest that plaques might not just cause damage but also somehow actively maintain it. The study, will appear in the Feb. 5 issue of the Journal of Clinical Investigation.

Keyword: Alzheimers
Link ID: 6731 - Posted: 01.21.2005

According to the Centers for Disease Control, tobacco use remains the leading preventable cause of death in the United States, causing more than 440,000 deaths each year and resulting in an annual cost of more than $75 billion in direct medical costs. The substance that makes cigarettes addictive is nicotine, which enhances the release of a neurotransmitter called dopamine, which is associated with the pleasure people get from eating, sex, and drugs. But Henry Lester, a neuroscientist at the California Institute of Technology, says nailing down exactly how nicotine behaves in the brain has been difficult. "We have known for, oh goodness, 450 years that nicotine does act on the body," he says. "But it's been unclear until the present which particular molecules it does act on. The question is, which of the various—and there are more than a dozen nicotine receptors in the body—is the one responsible for nicotine addiction?" Lester and his team believe they may have come closer to the answer. The brain has more than a dozen molecules—each with several "subunit" proteins—that respond to nicotine. These "nicotinic receptors" might act together or independently to cause addiction. Lester and his colleagues picked just one of them—the subunit alpha4 receptor—and genetically enhanced it in mice, creating "hypersensitive knock-in" mice. © ScienCentral, 2000- 2005.

Keyword: Drug Abuse
Link ID: 6730 - Posted: 06.24.2010

While there are essentially no disparities in general intelligence between the sexes, a UC Irvine study has found significant differences in brain areas where males and females manifest their intelligence. The study shows women having more white matter and men more gray matter related to intellectual skill, revealing that no single neuroanatomical structure determines general intelligence and that different types of brain designs are capable of producing equivalent intellectual performance. “These findings suggest that human evolution has created two different types of brains designed for equally intelligent behavior,” said Richard Haier, professor of psychology in the Department of Pediatrics and longtime human intelligence researcher, who led the study with colleagues at UCI and the University of New Mexico. “In addition, by pinpointing these gender-based intelligence areas, the study has the potential to aid research on dementia and other cognitive-impairment diseases in the brain.” Study results appear on the online version of NeuroImage. © Copyright 2002-2005 UC Regents

Keyword: Intelligence
Link ID: 6729 - Posted: 06.24.2010

Roxanne Khamsi One assumption lies at the root of efforts to keep the meat we eat safe from mad cow disease: that tissues beyond an animal's brain, spinal cord and immune system are free of the prions that cause the disease. A disturbing study now shows that assumption to be false. Researchers have found that if an animal falls ill with another infection, its immune response can carry large numbers of prions to organs throughout its body. "The rules no longer apply," warns pathologist Adriano Aguzzi at Zurich University Hospital, Switzerland, who led the research. Mad cow disease, more correctly known as bovine spongiform encephalopathy (BSE), is believed to be caused by rogue proteins called prions. When these prions enter the human food chain, they can cause the equivalent disease in humans, called new-variant Creutzfeldt-Jakob disease (vCJD). ©2005 Nature Publishing Group

Keyword: Prions
Link ID: 6728 - Posted: 06.24.2010

Roxanne Khamsi Can a drink a day prevent mental decline? The finding that older women who consume moderate amounts of alcohol score better on cognitive tests suggests that it can. An investigation has revealed for the first time that the brain can benefit from consumption of both beer and wine. In the early 1990s, researchers often referred to the 'French paradox' to support the idea that wine promotes good health1. The phrase refers to the fact that French people have a lower risk of heart attack than Americans do, even though their diets contain similar levels of fat. More recent studies have also linked modest beer consumption with a decreased risk in heart disease2. But although researchers know that moderate drinking benefits the heart, there haven't been any significant studies of whether moderate alcohol intake has any effect on the brain. ©2005 Nature Publishing Group

Keyword: Drug Abuse; Multiple Sclerosis
Link ID: 6727 - Posted: 06.24.2010

Harbour porpoises are being killed in increasing numbers by bottlenose dolphins around British coasts, possibly due to competition for food. The evidence comes from counts of porpoises washed up on coasts and from post-mortem examination of the animals. A lack of fish may be turning the dolphins on their cetacean relatives, according to some scientists. The findings, from researchers based at London's Natural History Museum, appear in BBC Wildlife magazine. Acting on their own, or with others, bottlenose dolphins ram the porpoises with their beaks, causing multiple injuries that include internal bleeding, rib fractures, ruptured lungs dislocated spines. The porpoises are less than two-thirds the size of the dolphins. Annual reports show a steady rise in the number of porpoise strandings, with 40 in 1995 and more than 120 in 2004. Most of the strandings in the study occurred on the Welsh coast. Post-mortem examinations reveal that of those 120, nearly three quarters were killed by bottlenose dolphins. This represents a three-fold increase in four years, according to the Strandings Co-ordination Group which is based at the Natural History Museum. Rod Penrose, a spokesman for the group commented: "A decline in harbour porpoise bycatch over the years in Wales has been replaced by this violent interaction between these two species. (C)BBC

Keyword: Aggression
Link ID: 6726 - Posted: 01.20.2005

Could the new weapon in the battle of the bulge be a nasal spray? Scientists are looking into a spray containing a naturally-occurring hormone, PYY3-36, which may tell the brain that the belly is full. In 2002, researchers from Imperial College in London discovered that the gastrointestinal hormone PYY3-36 appears to signal to the brain that the stomach is full. Steve Bloom, a researcher at Hammersmith Hospital and professor at Imperial College, reported it reduced food intake and body weight in rodents, and in a small study in humans. However, 42 scientists from 12 different labs around the world independently tested PYY3-36 in rodents and failed to see the same results, finding no significant effect on food intake or body weight. But now, a round of tests on rats by researchers at Creighton University School of Medicine and the Omaha Nebraska VA hospital is showing more positive results. "We now, I think, have clearly shown that PYY3-36 is a potent inhibitor of food intake," says Roger Reidelberger, professor of biomedical science at Creighton University. In the other studies, scientists used shots—either a placebo or the real thing—to deliver the hormone, causing Bloom and other scientists to suggest that if the rodents weren't properly adapted to being handled and injected, it may have stressed out the rodents and affected the results. Reidelberger reported in the journal Endocrinology that in the tests he and his team did, the hormone was delivered intravenously, to get a steady flow of lower doses."By infusing it like we do, over a period of hours, we can maintain the levels, much like what occurs under normal conditions after ingesting a meal," Reidelberger explains. © ScienCentral, 2000- 2005

Keyword: Obesity
Link ID: 6725 - Posted: 06.24.2010

Attention Deficit Hyperactivity Disorder (ADHD) affects three to five percent of all children, perhaps as many as two million American children, and two to three times more boys than girls. The most common ADHD behaviors fall into three categories: inattention, hyperactivity, and impulsivity; people with ADHD can have trouble with things like sitting still and focusing on tasks. In many cases, medications such as Ritalin are prescribed to children with ADHD. "They're kids who have difficulty at school, who have difficulty at home," explains Manzar Ashtari, professor of radiology and psychiatry at North Shore-Long Island Jewish Health System, who has studied ADHD in children for twenty years. "They're constantly fidgety, they lose things, they forget things, and they're very disruptive in their behavior and this will make them very lonely because they usually have no friends, and socially, basically, they are suffering, and that basically causes the parents to suffer as well." While ADHD is typically described as a chemical imbalance, Ashtari says she may have found a clue that helps explain physical differences in ADHD children's brains. Building on previous research on brain abnormalities in ADHD kids, Ashtari chose a new MRI-based technique called diffusion tensor imaging (DTI) to look at the white matter (which is composed of nerve fibers) in children's brains in more detail. DTI tracks water motion along the fibers that connect brain parts and transmit and receive information. After scanning 18 ADHD-diagnosed kids and 15 children without ADHD, she compared the structure and function of fibers in each group's brains, and found that "the motion of the water, the way it should be in normal controls, is not in ADHD kids." © ScienCentral, 2000- 2005. All rights reserved.

Keyword: ADHD
Link ID: 6724 - Posted: 06.24.2010

ST. LOUIS -- If you're a middle-aged guy who's packed on the pounds and now is battling to take them off, it's a 50-50 shot that your jeans are fitting tighter because of your genes, according to a Saint Louis University School of Public Health study. "About 50 percent of adult onset weight change remains genetic," says James C. Romeis, Ph.D., professor of health services research at Saint Louis University School of Public Health and the principal investigator of the study, which was published in a recent issue of Twin Research. Romeis studied sets of twins who served in the military during the Vietnam War –some identical (who share the same genes) and some fraternal (who share half their genes) – and found that genes account for more than 50 percent of the change in Body Mass Index. How we deal with our environment – what we eat, the amount we eat and how much we exercise – accounts for the other 50 percent. It's tough enough for Joe Six Pack to take off weight. But for those whose genes predispose them to be heavy, weight loss is going to be difficult – really difficult – and take extra effort.

Keyword: Obesity; Genes & Behavior
Link ID: 6723 - Posted: 06.24.2010

Transcranial magnetic stimulation (TMS), in which the brain is stimulated using a magnetic coil held outside the skull, has shown some promise in both studying the brain and in treating mental disorders such as depression, epilepsy, and Parkinson's disease. Such magnetic fields induce tiny electrical currents inside the skull that alter the activity of neural pathways. While TMS offers the advantages of relative safety and noninvasiveness, the results of its use in both research and treatment have been disappointing. In human studies, neurological effects of TMS have been transient, rarely lasting longer than 30 minutes. Now, researchers led by John Rothwell of the Institute of Neurology at University College London have devised a new TMS method that produces rapid, consistent, and controllable changes in the motor cortex of humans that last more than an hour. Their findings offer the potential for both more useful research studies using TMS as well as greater therapeutic application. In their studies, the researchers applied various patterns of repetitive magnetic pulses to the scalps of volunteer subjects. They aimed the pulses at the motor cortex that controls muscle response, because effects on the motor cortex can be objectively measured by recording the amount of electrical muscle response to stimulation. Specifically, the researchers positioned the magnetic coil over the motor cortex area that controls hand movement, and they measured response by determining the amount of muscle response in a small muscle in the subjects' hands.

Keyword: Miscellaneous
Link ID: 6722 - Posted: 01.20.2005

Jessica Ebert Cuttlefish may be the most talented quick-change artists in the animal kingdom. Single males can adopt a sophisticated feminine disguise to help them get near females that are guarded by large males. Now researchers have proved that the mimics, who can change their appearance instantaneously, are successfully mating with such females. Each year, during the winter, thousands of giant Australian cuttlefish (Sepia apama) gather on the southern coast of the continent to mate. The competition between males for the females is intense. On average, four males fight over each female, but the ratio can be as high as eleven to one. The winner of each challenge, usually a large male, guards his mate closely. But smaller males still manage to secure about a third of all matings. There is a range of tactics from which a 'sneaker' male can choose. The options include waiting until the consort male is busy fending off a challenge; meeting his mate under a rock as she prepares to lay an egg; and disguising oneself as an female. ©2005 Nature Publishing Group

Keyword: Sexual Behavior
Link ID: 6721 - Posted: 06.24.2010

Scientists say they now know more about what happens in the brains of former drug addicts when they crave cocaine. Tests on rats by US National Institute on Drug Abuse researchers found a way of blocking craving messages in their brains and preventing a relapse. Nature Neuroscience says the findings suggest the danger time is not straight after addicts stop taking the drug, but after they go long periods without it. The study found a protein in the brain plays a part in triggering cravings. In their study, the team trained rats to press a lever to receive an intravenous injection of cocaine. The rats were also trained to associate certain cues, such as a light, with the availability of the drug. Once this behaviour pattern was established, the researchers withheld both cocaine and cues associated with the drug from the rats for a month. When the rats were again exposed to the cues after 30 days of withdrawal, they showed much higher levels of craving than they did after just one day. When the researchers examined the rats, they looked at the activation of a protein called extracellular-signal regulated kinase (ERK) in the amygdala, a part of the brain involved in motivation and emotion. (C)BBC

Keyword: Drug Abuse
Link ID: 6720 - Posted: 01.19.2005

DISCOVER, FEBRUARY 2005 If you want to find alien life-forms, hold off on booking that trip to the moons of Saturn. You may only need to catch a plane to East Lansing, Michigan. The aliens of East Lansing are not made of carbon and water. They have no DNA. Billions of them are quietly colonizing a cluster of 200computers in the basement of the Plant and Soil Sciences building at Michigan State University. To peer into their world, however, you have to walk a few blocks west on Wilson Road to the engineering department and visit the Digital Evolution Laboratory. Here you'll find a crew of computer scientists, biologists, and even a philosopher or two gazing at computer monitors, watching the evolution of bizarre new life-forms. These are digital organisms-strings of commands-akin to computer viruses. Each organism can produce tens of thousands of copies of itself within a matter of minutes. Unlike computer viruses, however, they are made up of digital bits that can mutate in much the same way DNA mutates. A software program called Avida allows researchers to track the birth, life, and death of generation after generation of the digital organisms by scanning columns of numbers that pour down a computer screen like waterfalls. After more than a decade of development, Avida's digital organisms are now getting close to fulfilling the definition of biological life. “More and more of the features that biologists have said were necessary for life we can check off,” says Robert Pennock, a philosopher at Michigan State and a member of the Avida team. “Does this, does that, does this. Metabolism? Maybe not quite yet, but getting pretty close.” Copyright 2004 Carl Zimmer

Keyword: Evolution
Link ID: 6719 - Posted: 06.24.2010

Hypnosis has been misunderstood as a nightclub stunt, a loss of control and a type of sleep, but it's been a therapeutic tool for centuries. Dr. David Spiegel, associate chair of psychiatry and behavioral sciences at Stanford University School of Medicine describes hypnosis as a "focused state of attention." "Being hypnotized is something like looking through a telephoto lens," Spiegel explains. "What you see you see with great detail, but you're less aware of the surroundings, of the context in which you're experiencing it. So it's like getting so caught up in a good movie that you forget you're watching the movie, you enter the imagined world. That's what a hypnotic state is like. You wake up and pay attention in a highly focused way. So the parts of the brain that are involved in attention, the frontal cortex, for example, are turned on when you're hypnotized." Spiegel uses hypnosis—specifically, he teaches self-hypnosis—to help adults and children control their pain and anxiety during certain surgical procedures. He taught a self-hypnosis technique to 23 children aged four to 15 who had to undergo a stressful medical test called a voiding cystourethrography. He reported in the journal Pediatrics that they showed less distress, and the test was easier to conduct, and took nearly a third less time, compared to 21 children who underwent routine treatment. "In the last five years we've begun doing randomized trials for acute surgical and medical pain," he says, "and we've got a number a studies now that show that hypnosis reduces pain, reduces anxiety, reduces the amount of medication people need, reduces complications, and makes the procedures shorter, 17 to 20 minutes per procedure." © ScienCentral, 2000- 2005.

Keyword: Pain & Touch
Link ID: 6718 - Posted: 06.24.2010

New research published in the premier issue of Cell Metabolism finds that a single brain region is sufficient for normal control of blood sugar and activity level by the fat hormone leptin. The same region also exerts significant, though more modest, control over leptin's effects on body weight. The findings in mice provide insight into potential mechanisms underlying type II diabetes and suggest new avenues for treatment, according to the researchers. Secreted by fat cells, leptin signals the status of the body's energy content to the brain and is required for normal body weight and glucose balance. Mice lacking leptin develop obesity, diabetes, and inactivity, among other symptoms. The new results suggest that leptin signaling acts directly on the brain region known as the hypothalamic arcuate nucleus (ARH) to control insulin and glucose levels in the bloodstream, report Joel Elmquist and Bradford Lowell, both of Beth Israel Deaconess Medical Center and Harvard Medical School, and their colleagues. ARH neurons also mediate the majority, if not all, of the hormone's action on locomotor activity, they found. Leptin receptors in the ARH accounted for approximately 22 percent of the hormone's effects on body weight, the group reports, suggesting that other brain regions are also important to this hormonal function.

Keyword: Obesity
Link ID: 6717 - Posted: 01.19.2005

UCLA/VA scientists have identified a new gene that controls how the body produces and uses fat. Called lipin, the gene may provide a new target for therapies to control obesity, diabetes and other weight-related disorders. The first issue of the new journal Cell Metabolism publishes the findings in its January 2005 edition. "Lipin regulates how the body stores and burns fat. Our findings suggest that differences in lipin levels may play a role in why some people are more prone to weight gain than others who consume the same calories," said principal investigator Karen Reue, Ph.D., a professor of medicine and human genetics at the David Geffen School of Medicine at UCLA and a researcher at the Veterans Affairs Greater Los Angeles Healthcare System. In 2001, Reue's laboratory was the first to isolate the lipin gene and link it to lipodystrophy, a wasting disorder in which the body is unable to produce fat. She also found that too little lipin prevented both genetic and diet-related obesity. For this study, Reue and coauthor Jack Phan, Ph.D., tested whether too much lipin would produce the opposite effect. Her team developed animal models using two sets of specially bred mice. Each group had a genetic mutation that boosted the level of lipin – one group in their fat tissue and the other group in their muscles.

Keyword: Obesity
Link ID: 6716 - Posted: 06.24.2010

A naturally occurring hallucinogen advocated by some clinicians as a potent anti-addiction drug has been rigorously studied for the first time, confirming its ability to block alcohol craving in rodents, and clarifying how it works in the brain. The new research findings about the drug Ibogaine open the way for development of other drugs to reverse addiction without Ibogaine's side effects, potentially adding to the small arsenal of drugs that effectively combat addiction. Derived from a West African shrub, Ibogaine has been championed for years by a cadre of clinicians and drug treatment advocates impressed with its ability to reverse withdrawal symptoms and craving for alcohol and various drugs of abuse. It has been used outside of the U.S. to treat addiction by American and other clinicians. But its side effects, including hallucinations, which made it popular in the 1960s drug culture, and evidence of toxicity to certain nerve cells in rodent studies have discouraged careful studies of its clinical potential against drug and alcohol addiction. The FDA has not approved use of Ibogaine in the U.S. Scientists at UCSF's Ernest Gallo Clinic and Research Center have now shown definitively in experiments with mice and rats that Ibogaine does reduce alcohol consumption, and they have determined that it does so by increasing the level of a brain protein known as glial cell line-derived neurotrophic factor, or GDNF. In a separate study, they demonstrated that GDNF by itself decreases alcohol consumption.

Keyword: Drug Abuse
Link ID: 6715 - Posted: 01.19.2005

By JANE E. BRODY A woman who lived for years in my neighborhood periodically appeared at a window and shouted obscenities into the street. Passers-by were appalled, but I felt what had to be the painful humiliation of someone who had no ability to control this seemingly antisocial behavior. I realized that the woman was afflicted with Tourette's syndrome, a lifelong neurological disorder with symptoms that contrary to popular belief, only rarely include the involuntary shouting of obscenities. I now know that the disorder is associated with a wide range of confusing symptoms that often result in delays in diagnosis and treatment that can last years. The problem was eloquently described in a two-part article last August in Contemporary Pediatrics. In his report, Dr. Samuel H. Zinner, a pediatrician at the University of Washington specializing in developmental and behavioral problems, points out that the syndrome "often goes undiagnosed or misdiagnosed." "Misconceptions about this tic disorder are customary," he adds, "with the syndrome often perceived as characterized by bizarre, fitful behaviors or comical outbursts of uncontrollable profanity." Copyright 2005 The New York Times Company

Keyword: Tourettes
Link ID: 6714 - Posted: 01.18.2005