Carl T. Hall, Chronicle Science Writer Researchers in San Diego have designed mice containing fully functional human nerve cells as a novel way to study and potentially treat neurodegenerative diseases such as Parkinson's and Alzheimer's. The neurons were formed in the brains of mice that had been injected with human embryonic stem cells as 2-week-old embryos. Studies at the Salk Institute for Biological Sciences in La Jolla showed that the human cells migrated throughout the mouse brain and took on the traits of their mouse-cell neighbors. The results present direct evidence that primitive human stem cells can be cultured in the lab, be injected into an animal, and then develop into a particular type of desired cell. The report appears in this week's Proceedings of the National Academy of Sciences. Scientists said it was the first time cultured human embryonic stem cells have been shown to develop into a particular type of cell in the body of another living species. Creation of a so-called "mouse-human chimeric nervous system" stops well short of spawning a mouse with a human-like cerebral cortex. In fact, all the brain structures of the four mice used in the Salk experiments had been formed before the human cells were injected, and less than 0.1 percent of the mice brain cells were found to be of human origin. ©2005 San Francisco Chronicle

Keyword: Stem Cells; Parkinsons
Link ID: 8309 - Posted: 06.24.2010

A new study designed to test whether androgenic-anabolic steroids may be addictive found that hamsters exposed to the compounds demonstrated addictive behavior over time. The research, conducted by the University of Southern California's Keck School of Medicine was released at the American College of Neuropsychopharmacology's (ACNP) annual conference. "Most people use anabolic steroids to enhance their physical performance, but they deny that steroids may be addictive," noted lead researcher Ruth Wood, PhD, Professor of Cell and Neurobiology at USC. "Unlike other commonly abused drugs, the primary motivation for steroid users is not to get high, but rather to achieve enhanced athletic performance and increased muscle mass. The complex motivation for steroid use makes it difficult to determine the addictive properties of anabolic steroids in humans. Our goal was to create an experimental model of addiction where athletic performance and other reinforcing effects are irrelevant." Wood's study is among the first to examine the potential for anabolic steroid addiction. The research was modeled after well-established methods used to study highly addictive drugs, such as cocaine and heroin. Hamsters were implanted with small cannulas for self-administration of commonly abused steroids into their brains. The animals then spent four hours per day in a chamber with access to two delivery mechanisms. When the hamster operated the active mechanism, he received 1 microgram of testosterone, or one of several commonly abused steroids: nandrolone, drostanolone, stanozolol, or oxymetholone. The inactive mechanism produced no response. A computer recorded the number of times each animal used the active and inactive delivery mechanisms. Overall, the animals showed a marked preference for testosterone, nandrolone or drostanolone, engaging the active delivery mechanism twice as often as the control.

Keyword: Drug Abuse; Hormones & Behavior
Link ID: 8308 - Posted: 12.14.2005

Researchers have discovered a new drug that raises the level of endocannabinoids--the 'brain's own cannabis'--providing anti-depressant effects. The new research published in this week's Proceedings of the National Academy of Sciences (PNAS), suggests the new drug, called URB597, could represent a safer alternative to cannabis for the treatment of pain and depression, and open the door to new and improved treatments for clinical depression--a condition that affects around 20% of Canadians. In preclinical laboratory tests researchers found that URB597 increased the production of endocannabinoids by blocking their degradation, resulting in measurable antidepressant effects. "This is the first time it has been shown that a drug that increases endocannabinoids in the brain can improve your mood," says the lead investigator Dr. Gabriella Gobbi, an MUHC and Université de Montréal researcher. Endocannabinoids are chemicals released by the brain under certain conditions, like exercise; they stimulate specific brain receptors that can trigger feelings of well-being. The researchers, which included scientists from the University of California at Irvine, were able to measure serotonin and noradrenaline activity as a result of the increased endocannabinoids, and also conducted standard experiments to gauge the 'mood' of their subjects and confirm their findings.

Keyword: Depression; Drug Abuse
Link ID: 8307 - Posted: 12.14.2005

By Sally Squires Washington Post Staff Writer If you haven't heard of hoodia or green tea extract, you haven't been checking your e-mail or spending much time on the Web. Since the Food and Drug Administration (FDA) last year banned ephedra, the long-standing leader among supplements promoted to help people lose weight, hoodia and green tree extract have taken a high profile among the products being offered to fill the void. E-mail blasts promoting them are sent to millions of addresses, and Web sites promoting them are ubiquitous online. With two-thirds of U.S. adults overweight or obese and many of them unhappy about it, Americans' hunger for diet supplements is nothing new. Neither is the fact that little science has been done to prove that heavily promoted products are effective or even safe. Still, sales are huge. These herbal products offer the promise of a natural remedy for weight loss, and they're available without a prescription. Together, over-the-counter weight loss products -- which also include bitter orange, chitosan, guar gum, L-carnitine and dozens more -- account for nearly $2 billion in annual sales in the United States, according to the Nutrition Business Journal. Even ephedra, banned last year by the FDA after its use was linked to several deaths, is creeping back on the market, thanks to a federal court decision that opened a legal crack to manufacturers. © 2005 The Washington Post Company

Keyword: Obesity
Link ID: 8306 - Posted: 06.24.2010

By CARL ZIMMER I drove into New Haven on a recent morning with a burning question on my mind. How did my daughter do against the chimpanzees? A month before, I had found a letter in the cubby of my daughter Charlotte at her preschool. It was from a graduate student at Yale asking for volunteers for a psychological study. The student, Derek Lyons, wanted to observe how 3- and 4-year-olds learn. I was curious, so I got in touch. Mr. Lyons explained how his study might shed light on human evolution. His study would build on a paper published in the July issue of the journal Animal Cognition by Victoria Horner and Andrew Whiten, two psychologists at the University of St. Andrews in Scotland. Dr. Horner and Dr. Whiten described the way they showed young chimps how to retrieve food from a box. The box was painted black and had a door on one side and a bolt running across the top. The food was hidden in a tube behind the door. When they showed the chimpanzees how to retrieve the food, the researchers added some unnecessary steps. Before they opened the door, they pulled back the bolt and tapped the top of the box with a stick. Only after they had pushed the bolt back in place did they finally open the door and fish out the food. Copyright 2005The New York Times Company

Keyword: Learning & Memory; Development of the Brain
Link ID: 8305 - Posted: 12.13.2005

By WILLIAM J. BROAD For centuries, the tusk of the narwhal has fascinated and baffled. Narwhal tusks, up to nine feet long, were sold as unicorn horns in ages past, often for many times their weight in gold since they were said to possess magic powers. In the 16th century, Queen Elizabeth received a tusk valued at £10,000 - the cost of a castle. Austrian lore holds that Kaiser Karl the Fifth paid off a large national debt with two tusks. In Vienna, the Hapsburgs had one made into a scepter heavy with diamonds, rubies, sapphires and emeralds. Scientists have long tried to explain why a stocky whale that lives in arctic waters, feeding on cod and other creatures that flourish amid the pack ice, should wield such a long tusk. The theories about how the narwhal uses the tusk have included breaking ice, spearing fish, piercing ships, transmitting sound, shedding excess body heat, poking the seabed for food, wooing females, defending baby narwhals and establishing dominance in social hierarchies. But a team of scientists from Harvard and the National Institute of Standards and Technology has now made a startling discovery: the tusk, it turns out, forms a sensory organ of exceptional size and sensitivity, making the living appendage one of the planet's most remarkable, and one that in some ways outdoes its own mythology. The find came when the team turned an electron microscope on the tusk's material and found new subtleties of dental anatomy. The close-ups showed that 10 million nerve endings tunnel from the tusk's core toward its outer surface, communicating with the outside world. The scientists say the nerves can detect subtle changes of temperature, pressure, particle gradients and probably much else, giving the animal unique insights. Copyright 2005 The New York Times Company

Keyword: Pain & Touch
Link ID: 8304 - Posted: 12.13.2005

Working with mice, University of Wisconsin-Madison researchers have developed the basis for a therapeutic strategy that could provide hope for children afflicted with Krabbe's disease, a fatal nervous system disorder. Writing this week (Dec. 12, 2005) in the Proceedings of the National Academy of Sciences (PNAS), a team of researchers at the UW-Madison School of Veterinary Medicine describes experiments that effectively promoted the ability of defective cells to take up and utilize an enzyme that is essential for the maintenance of a critical sheathing of nerve fibers. The work centers on devising strategies to treat inherited diseases of the nervous system in which cells fail to maintain myelin, a protective sheathing that envelops nerve fibers and acts like the insulation on an electric wire. Myelin ensures the effective transmission of the signals routinely conducted by the nervous system. For those afflicted with Krabbe's disease, the loss of myelin results in arrested motor and mental development, seizures, paralysis and, ultimately, death. The Wisconsin experiments, led by Ian Duncan, a UW-Madison professor of medical sciences who is an expert on diseases of myelin, explored how cells obtained from a mouse model of Krabbe's disease could be reinvigorated by replacing a missing enzyme, and thus allow the healthy maintenance of myelin.

Keyword: Development of the Brain
Link ID: 8303 - Posted: 12.13.2005

DURHAM, N.C. -- Researchers have discovered the first brain regulatory gene that shows clear evidence of evolution from lower primates to humans. They said the evolution of humans might well have depended in part on hyperactivation of the gene, called prodynorphin (PDYN), that plays critical roles in regulating perception, behavior and memory. They reported that, compared to lower primates, humans possess a distinctive variant in a regulatory segment of the prodynorphin gene, which is a precursor molecule for a range of regulatory proteins called "neuropeptides." This variant increases the amount of prodynorphin produced in the brain. While the researchers do not understand the physiological implications of the activated PDYN gene in humans, they said their finding offers an important and intriguing piece of a puzzle of the mechanism by which humans evolved from lower primates. They also said that the discovery of this first evolutionarily selected gene is likely only the beginning of a new pathway of exploring how the pressure of natural selection influenced evolution of other genes. They also said their finding demonstrates how evolution can act more efficiently to alter the regulatory segments, or "promoters," that determine genes' activity, rather than on the gene segment that determines the structure of the protein it produces. Such regulatory alteration, they said, can more readily generate variability than the hit-or-miss mutations that alter protein structure and function.

Keyword: Evolution; Development of the Brain
Link ID: 8302 - Posted: 12.13.2005

CHICAGO – Testosterone replacement therapy may help improve the quality of life for elderly men with mild cases of Alzheimer's disease, according to a study posted online today that will appear in the February 2006 print issue of Archives of Neurology, one of the JAMA/Archives journals. "There is a compelling need for therapies that prevent, defer the onset, slow the progression, or improve the symptoms of Alzheimer disease (AD)," the authors provide as background information in the article. They note that hormonal therapies have been the focus of research attention in recent years since male aging is associated with a gradual progressive decline in testosterone levels. "The gradual decline in testosterone level is associated with decreased muscle mass and strength, osteoporosis, decreased libido, mood alterations, and changes in cognition, conditions that may be reversed with testosterone replacement." The authors add that the age-related decline in testosterone is potentially relevant to AD as previous studies have found significantly lower concentrations of the hormone in middle-aged and elderly men who developed AD. Po H. Lu, Psy.D., from the David Geffen School of Medicine, University of California, Los Angeles, and colleagues conducted a 24-week, randomized study to evaluate the effects of testosterone therapy on cognition, neuropsychiatric symptoms, and quality of life in 16 male patients with mild AD and 22 healthy elderly men who served as controls. The study participants were randomized to receive packets of gel to apply on their skin that either contained testosterone or a placebo. Standardized tests were administered at least twice (baseline and end) during the study for the assessment of cognitive functions and quality of life.

Keyword: Alzheimers; Hormones & Behavior
Link ID: 8301 - Posted: 06.24.2010

Depression and anxiety are common problems for people whose epilepsy cannot be controlled by medication. A new study found that depression and anxiety improve significantly after epilepsy surgery. The study, which is published in the December 13, 2005, issue of Neurology, the scientific journal of the American Academy of Neurology, found that the rate of depression and anxiety disorders decreased by more than 50 percent up to two years after the surgery. People who no longer experienced any seizures after surgery were even more likely to be free of depression and anxiety. "These results are important because depression and anxiety can significantly affect the quality of life," said study author Orrin Devinsky, MD, Professor of Neurology, Neurosurgery, and Psychiatry at New York University School of Medicine and Director of the NYU Comprehensive Epilepsy Center. "For people with refractory epilepsy, studies show that depression is more likely to affect their quality of life than how often they have seizures or how many drugs they have to take." The study involved 360 people in seven U.S. epilepsy centers who were undergoing epilepsy surgery to remove the area of the brain producing the seizures. Epilepsy surgery is generally reserved for those whose seizures cannot be adequately controlled by medication. The majority of participants had surgery on the brain's temporal lobe. The participants' mental health and any symptoms of depression and anxiety were evaluated before surgery and at three months, one year, and two years after surgery.

Keyword: Epilepsy; Depression
Link ID: 8300 - Posted: 12.13.2005

Roxanne Khamsi Eye cells transplanted into the brain have mitigated the symptoms of Parkinson's disease in a preliminary trial involving six patients. The findings of the small study suggest that injections of such cells can partly reverse the motion difficulties associated with the illness. The eye cells seem to produce a natural form of a drug that is frequently given to patients, but release it in a steady, even flow that prevents some of the nasty side-effects of the medicine. Parkinson's disease is a debilitating neurological disorder thought to affect brain cells' ability to produce the powerful cell-signalling molecule dopamine. For the past three decades, patients with this disorder have typically received a medication called levodopa (L-DOPA), which replaces lost dopamine. Doses of L-DOPA help to alleviate some of the symptoms of Parkinson's disease, which include tremor, muscle rigidity and slowed motion. But only for a while. Over time, patients respond less and less to L-DOPA. But upping the dosage can lead to a side-effect known as dyskinesias: involuntary movements resulting in fragmented or jerky motions. ©2005 Nature Publishing Group

Keyword: Parkinsons
Link ID: 8299 - Posted: 06.24.2010

Andreas von Bubnoff Researchers have managed to teach people suffering chronic pain to reduce their own discomfort simply by controlling their thoughts. It's unclear how long the effect lasts, but the researchers hope that this approach could one day be used to treat chronic pain, which affects tens of millions of people in the United States alone and is a major reason for sick leave. The team, led by Christopher deCharms, showed eight patients real-time functional magnetic resonance imaging, or fMRI, of the activity in their rostral anterior cingulate cortex (rACC), a part of the brain known to be involved with pain control. They asked participants to try to increase or decrease activity in this area, by focusing on their pain or by distracting themselves from it. After only a few training sessions, most patients could reduce the activity in their rACC on command. These patients said that their pain lessened by about 50%, the researchers report this week in the Proceedings of the National Academies of Sciences1. The method also worked with healthy people involved in the study who were given painful stimuli to their hands and asked to try and control their response. ©2005 Nature Publishing Group

Keyword: Pain & Touch
Link ID: 8298 - Posted: 06.24.2010

A brain mechanism that may link violent computer games with aggression has been discovered by researchers in the US. The work goes some way towards demonstrating a causal link between the two - rather than a simple association. Many studies have concluded that people who play violent video games are more aggressive, more likely to commit violent crimes, and less likely to help others. But critics argue these correlations merely prove that violent people gravitate towards violent games, not that games can change behaviour. Now psychologist Bruce Bartholow from the University of Missouri-Columbia and colleagues have found that people who play violent video games show diminished brain responses to images of real-life violence, such as gun attacks, but not to other emotionally disturbing pictures, such as those of dead animals, or sick children. And the reduction in response is correlated with aggressive behaviour. The brain activity they measured, called the P300 response, is a characteristic signal seen in an EEG (electroencephalogram) recording of brain waves as we register an image. The P300 reflects an evaluation of the emotional content of an image says Bartholow, being larger if people are surprised or disturbed by an image, or if something is novel. © Copyright Reed Business Information Ltd.

Keyword: Aggression; Emotions
Link ID: 8297 - Posted: 06.24.2010

Using drugs to block chemical brain signals may stop epileptic seizures in children and the onset of a chronic form of the condition, a study says. Researchers found seizures in the developing brain could be triggered by pulses of a brain chemical known as GABA impacting on nerve cells. The French Institute of Neurobiology team said such reactions left the nerve cells prone to regular seizures. The study on rats features in the journal Neuron. One in 20 people will have a seizure at some point, but many will "grow out of it" by the time they reach adulthood. However, for some it develops into a more serious condition - about 450,000 in the UK have regular epilepsy seizures. The French team looked at how seizures in early life developed into chronic epilepsy. Analysing the brains of baby rats, they used drugs to both block GABA signals and also to prompt seizures. They found that GABA-triggered nerve cells prompted seizures in young brains and these seizures featured so-called fast oscillations of electrical activity that are required to transform nerve cells into an "persistent epileptic state". When they carried out experiments on adult rats, the researchers found GABA signals were also involved in seizures, but did not lead to the development of chronic epilepsy. There are many different factors which can induce a seizure, of which GABA signals are just one. Other chemical imbalances, alcohol and fatigue can all play a role. Report author Yehezkel Ben-Ari said the findings could help inform the development of new drugs. (C)BBC

Keyword: Epilepsy
Link ID: 8296 - Posted: 12.10.2005

A brain protein switches from 'Jekyll to Hyde' - building memories, but also playing a role in killing brain cells in conditions such as dementia. Harvard Medical School researchers say the switch is caused by the brain trying to compensate for the damage done by such conditions. Writing in Neuron, they said their study of mice could offer clues about what happens in human brains. Dementia researchers agreed the work could further understanding. The researchers focused on enzymes in the brain which control its biochemistry. Abnormal patterns had already been seen in the brains of patients with Alzheimer's disease. The researchers looked at the influence of a protein called p25 which appears to play a role in triggering these abnormal patterns - in certain circumstances. In the study, the researchers "switched on" p25 at will in the brain's learning and memory centre, the hippocampus. In these mice, they found that switching on p25 for only two weeks boosted learning and memory compared to normal mice. But if the p25 was switched on for six weeks, mice displayed impaired learning and memory in tests. Physiological studies showed that these mice showed significant brain damage and lost nerve cells in the hippocampus. But those who had elevated p25 levels for just two weeks had no such effects. (C)BBC

Keyword: Alzheimers; Learning & Memory
Link ID: 8295 - Posted: 12.10.2005

By Shankar Vedantam Washington Post Staff Writer The 48-year-old man turned down a job because he feared that a co-worker would be gay. He was upset that gay culture was becoming mainstream and blamed most of his personal, professional and emotional problems on the gay and lesbian movement. These fixations preoccupied him every day. Articles in magazines about gays made him agitated. He confessed that his fears had left him socially isolated and unemployed for years: A recovering alcoholic, the man even avoided 12-step meetings out of fear he might encounter a gay person. "He had a fixed delusion about the world," said Sondra E. Solomon, a psychologist at the University of Vermont who treated the man for two years. "He felt under attack, he felt threatened." Mental health practitioners say they regularly confront extreme forms of racism, homophobia and other prejudice in the course of therapy, and that some patients are disabled by these beliefs. As doctors increasingly weigh the effects of race and culture on mental illness, some are asking whether pathological bias ought to be an official psychiatric diagnosis. © 2005 The Washington Post Company

Keyword: Emotions
Link ID: 8294 - Posted: 06.24.2010

At the end of the day, what makes you you? Author Shannon Moffett attempts to answer that question, among others, in The Three-Pound Enigma: The Human Brain and the Quest to Unlock Its Mysteries. In an age when we are becoming immune to the wonders of medicine due simply to the frequency of new discoveries and breakthroughs, it is both humbling and inspiring to find how very much there still is to learn about the three-pound organ at the top of our spinal column that we call home. Moffett opens her book with a bang, literally, introducing the reader to neurosurgeon Roberta Glick, whose main case of the day involves removing a precariously located bullet in a patient’s brain. Between describing the complex physical and neurological processes that Glick must not impair while removing the bullet, Moffett provides a compelling character portrait of the doctor herself, including her self-described “geriatric motherhood” (due to the demands of her profession, Glick waited to have children until she was almost forty), as well as a technically competent introduction to the physical structure of the brain. The author’s skillful combination of character description with straightforward medical and scientific description of the brain and our mental processes is in evidence throughout the entire book. Although many science books are not lauded for their attention to character or story details, Moffett’s succeeds as both a highly readable and surprisingly suspenseful book, as well as a comprehensively detailed one. In subsequent chapters she interviews various brain and consciousness specialists, including John Gabrielli (an authority on memory), Christof Koch and Francis Crick (Crick is more well-known as the co-discoverer, along with James Watson, of DNA), who are busily engaged trying to chart the future of research on consciousness, and various sleep, psychiatry, and meditation specialists who are looking for their own ways to unlock the secrets of our mental beings.

Keyword: Miscellaneous
Link ID: 8293 - Posted: 06.24.2010

The electric eel generates large electric currents by way of a highly specialized nervous system that has the capacity to synchronize the activity of disc-shaped, electricity-producing cells packed into a specialized electric organ. The nervous system does this through a command nucleus that decides when the electric organ will fire. When the command is given, a complex array of nerves makes sure that the thousands of cells activate at once, no matter how far they are from the command nucleus. Each electrogenic cell carries a negative charge of a little less than 100 microvolts on its outside compared to its inside. When the command signal arrives, the nerve terminal releases a minute puff of acetylcholine, a neurotransmitter. This creates a transient path with low electrical resistance connecting the inside and the outside of one side of the cell. Thus, each cell behaves like a battery with the activated side carrying a negative charge and the opposite side a positive one. Because the cells are oriented inside the electric organ like a series of batteries piled into a flashlight, the current generated by an activated cell "shocks" any inactive neighbor into action, setting off an avalanche of activation that runs its course in just two milliseconds or so. This practically simultaneous start-up creates a short-lived current flowing along the eel's body. If the eel lived in air, the current could be as high as one ampere, turning the creature's body into the equivalent of a 500-volt battery. But eels live in water, which provides additional outlets for the current. They thus generate a larger voltage, but a divided, and therefore diminished, current. © 1996-2005 Scientific American, Inc.

Keyword: Pain & Touch
Link ID: 8292 - Posted: 06.24.2010

Stock market traders are trained to keep a cool head where money is concerned. But what about the rest of us? "I think the people who you see trading on the floor of the exchanges have so much experience that they probably, to a great extent, not completely but to a great extent, learn to control their emotions or work with their emotions," says economist George Loewenstein, from Carnegie Mellon University. "It's the individual investors that are often led astray by their emotions." Loewenstein and his research team have been studying the role of emotion in decision-making. "My collaborators and I are very interested in the role of immediate emotions in human behavior, the idea that people's behavior is determined, not by an assessment of the consequences of decisions, but simply by the immediate emotions that they're experiencing," he explains. "Emotions are clearly very important for human functioning, and people who have damage to emotional parts of the brain exhibit all sorts of different problems. But emotions also have a downside… they can lead people to be very aggressive, they can lead people to be very impatient." In particular, Loewenstein's group is interested in whether it is possible that people with damage to the emotion parts of the brain might make better decisions, economically more advantageous decisions, than normal people in certain circumstances. Research has shown that normal people tend to be pathologically risk averse. © ScienCentral, 2000-2005.

Keyword: Emotions
Link ID: 8291 - Posted: 06.24.2010

By Marc Kaufman and Shankar Vedantam The Food and Drug Administration warned pregnant women and their doctors away from the antidepressant Paxil yesterday because of an increased risk of heart defects in newborns. With the warning, the agency for the first time placed a popular antidepressant -- one in the same drug class as Prozac and Zoloft -- into its second-highest category for risk of birth defects. The agency did not say Paxil could never be used by pregnant women, but it did say the FDA "is advising patients that this drug should usually not be taken during pregnancy." The advisory is based on early results from two studies, which found that women who took Paxil in the first three months of pregnancy were 1 1/2 to two times more likely to give birth to a child with a heart defect than women who took other antidepressants or pregnant women overall. The studies found that Paxil had a risk of birth defects that other common antidepressants did not. "If you're on Paxil and pregnant, our advice is to talk to your physician and consider switching to a different drug," said Robert Temple, the FDA's director of medical policy. "Abrupt withdrawal of Paxil has its own problems, but the clear suggestion here is that you might want to think about a change." © 2005 The Washington Post Company

Keyword: Depression; Development of the Brain
Link ID: 8290 - Posted: 06.24.2010