Once, leptin seemed like the ultimate fat-shedding drug: a natural appetite-quelling hormone whose absence causes obesity. Boost someone's blood levels of leptin, obesity researchers suspected, and they'd eat less. A clinical trial nixed that idea when obese people didn't respond to leptin treatment. But a new study shows that that low leptin can lead to chubbiness, suggesting that the hormone might help some people shed pounds. In 1994 scientists discovered that mice missing both copies of their leptin gene develop excessive body fat, extreme hunger, and sterility. Soon afterwards, endocrinologist Stephen O'Rahilly of Addenbrooke's Hospital in Cambridge, U.K., identified two cousins with defects in both copies of their leptin genes. They produce virtually no leptin and show the hallmarks of mouse leptin deficiency. The childrens' parents weren't grossly obese, even though each carried one defective and one normal copy of the leptin gene. Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Obesity
Link ID: 903 - Posted: 11.02.2001

By Roger Highfield THE seat of temperance has been located by experiments on men watching X-rated films, revealing a region in the front of the brain that can control our most primitive sexual urges. Researchers at the University of Montreal in Canada discovered the areas of the brain that play this inhibitory role by asking a dozen men to watch clips of erotic movies and films that were sexually neutral. In the Journal of Neuroscience, Mario Beauregard, Johanne Levesque and Pierre Bourgouin report that when the men gave free rein to sexual arousal there was activation of a brain centre called the limbic system, or "emotional brain". © Copyright Telegraph Group Limited 2000.

Keyword: Attention; Brain imaging
Link ID: 902 - Posted: 11.02.2001

PHILIP BALL Canaries owe their complex songs to good voice control, according to a new mathematical model. By manipulating the air pressure and muscles in their vocal organ, the syrinx, birds can produce a huge repertoire of sound, Tim Gardner of Rockefeller University in New York and colleagues calculate1. The team hopes that uncovering the mechanics of sound generation in birdsong might help to explain how the animals' singing is linked to brain activity, and thus how birds learn their songs. Male canaries and other birds use song as a mating call - a singer's prowess may advertise his fitness and wow females. 1.Gardner, T., Cecchi, G., Magnasco, M., Laje, R. & Mindlin, G. B. Simple motor gestures for birdsongs. Physical Review Letters, 87, 208101 (2001). © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Animal Communication; Language
Link ID: 901 - Posted: 11.02.2001

CHAMPAIGN, Ill. - A new approach to improving the detection and removal of tumors has been developed by scientists at the University of Illinois. Similar in operation to ultrasound, optical coherence tomography (OCT) is an optical technique that allows high-resolution imaging of tissue. The technique works by focusing a beam of near-infrared light (like that used in CD players) into tissue and measuring the intensity and position of the resulting reflections. To make OCT work better, UI researchers have developed injectable contrast agents that will help identify tumors early in their growth. "OCT is a relatively new technology that is just beginning to be used in the clinical setting," said Stephen Boppart, a professor of electrical and computer engineering and of bioengineering. "No doubt there will be many instances where we will need to improve the contrast." In collaboration with UI chemistry professor Ken Suslick, Boppart and his students have developed microspheres that enhance the contrast for OCT. The tiny spheres – filled with air or some other light-scattering media – create a stronger signal than the surrounding tissue.

Keyword: Brain imaging
Link ID: 900 - Posted: 06.24.2010

- Researchers have discovered that a gene previously implicated in a variety of forms of cancer is also a key regulator of neural stem cell proliferation. Understanding how the protein expressed by the gene PTEN promotes the proliferation of neural stem cells could aid efforts to use stem cells in treating neurological disorders. Howard Hughes Medical Institute investigator Hong Wu and colleagues at the UCLA School of Medicine reported on the regulatory role of Pten in the November 1, 2001, Science Express, the online counterpart of the journal Science. ©2001 Howard Hughes Medical Institute

Keyword: Stem Cells
Link ID: 899 - Posted: 11.02.2001

By CHRISTOPHER NEWTON, Associated Press Writer WASHINGTON (AP) - When you're asleep, your mind uses dream time to process information for use when you're awake. Or not. New research papers from sleep scientists, featured in the November issue of Science magazine, reach opposite conclusions. Robert Stickgold, a professor at the Department of Psychiatry at Harvard Medical School, produced research he believes provides compelling evidence that the mind works hard at night. "The brain is taking information and helping us put it into a form that we can understand," Stickgold said. "Understanding the complexity of the world is one of our brain's most difficult tasks. It needs more than our hours of awake time to get the job done." Across the divide is Jerome Siegel, a researcher at the Center for Sleep Research of the Department of Veterans Affairs. Siegel's analysis, which looks into dozens of studies done on dreams and learning, found no evidence that the sleeping mind does anything important. © 2001 Associated Press. All Rights Reserved.

Keyword: Sleep; Learning & Memory
Link ID: 898 - Posted: 11.02.2001

Reclassifying cannabis isn't enough to break the link to hard drugs The great cannabis debate has been reignited in Britain by a government proposal to reclassify weed as a "softer" drug. If it's passed, Britain will be become one of many countries that are reducing the penalties for cannabis use. So is this move part of a dangerous liberal trend that will lead to an explosion in the use of cannabis and other, more dangerous drugs? Or is it a long overdue step that does not go far enough towards breaking the link between marijuana, hard drugs and crime? In Britain's three-tier classification system, cannabis is currently in Class B, along with amphetamines - a position that many argue is out of keeping with the danger it poses. The proposal is to reduce it to Class C, along with drugs such as anabolic steroids. From New Scientist, 3 November 2001 © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse
Link ID: 897 - Posted: 11.02.2001

The axon is vital for cellular communication. Yet, in the adult spinal cord and brain these thin processes that jut out from nerve cells have trouble regenerating after an injury. The result is permanent impairments, such as a loss of movement. For years, scientists have searched to understand why axons refuse to rebuild. Now increasing research finds that a covering on the axon, termed myelin, is at least partly to blame. The discovery is helping researchers get closer to developing human treatments that could repair damage and restore function. After an unexpected detour on Saturday's bike ride, the gouged skin on your knee easily repairs itself. No such luck for your damaged spinal cord. Copyright © 2001 Society for Neuroscience. All rights reserved.

Keyword: Glia; Multiple Sclerosis
Link ID: 896 - Posted: 11.01.2001

Mild Head Injury Increases The Brain's Vulnerability To Further Damage (Philadelphia, PA) They may want to 'shake it off' and get back into the game, but a single head injury--even a mild one--can put athletes at risk for further traumatic brain injuries. According to researchers at the University of Pennsylvania School of Medicine, the brain has an increased vulnerability to severe, perhaps permanent, injury for at least 24 hours following a concussion. Their results, published in the November issue of the Journal of Neurosurgery, have serious implications for victims of accidents and abuse, as well as amateur and professional athletes. The researchers believe their work provides a new model for looking at repetitive head injuries (RHI). The prospect that athletes may be returning to the field too soon after a head injury is alarming, say the researchers. Indeed, the research was funded by NFL Charities, the philanthropic arm of the National Football League.

Keyword: Brain Injury/Concussion
Link ID: 892 - Posted: 11.01.2001

A sharp drop in stress hormones after giving birth to a child may predispose some women to develop certain conditions in which the immune system attacks the body's own tissues, according to researchers at the National Institutes of Health. The study was conducted by researchers at the National Institute of Child Health and Human Development (NICHD) and the National Institute of Arthritis, Musculoskeletal and Skin Diseases. The study appeared in the October issue of The Journal of Clinical Endocrinology and Metabolism. "This finding has important implications for understanding why immune disorders may subside during pregnancy, but flare up again after birth," Duane Alexander, M.D., director of the NICHD.

Keyword: Hormones & Behavior; Multiple Sclerosis
Link ID: 891 - Posted: 11.01.2001

When it comes to the origins of placental mammals, fossils and DNA rarely see eye to eye. Some molecular clocks based on genetic differences estimate that major lineages began to split and diversify as far back as 100 million years ago. But the oldest undisputed fossils of placental mammals--those that bear live young rather than lay eggs or gestate them outside the womb like marsupials--date to only 65 million years ago. Now a team of paleontologists argues that an 85-million-year-old extinct mammal called a zalambdalestid is placental, which may help reconcile the molecular data with the fossils. Five years ago, paleontologist David Archibald at San Diego State University proposed that a different group of 85-million-year-old mammals called the zhelestids was placental, closely related to the lineage that led to the hoofed mammals (Science, 24 May 1996, p. 1150). The claim remains controversial. Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 890 - Posted: 11.01.2001

TOM CLARKE "Potassium channels underlie all our movements and thoughts," says Rod MacKinnon of Rockefeller University in New York. His team has now unravelled the molecular mechanics of these minute protein pores. Some say the work merits a Nobel Prize. Potassium (K+) channels power the transmission of nerve signals through the body and the brain by ushering K+ ions in and out of our cells. MacKinnon and his colleagues have taken high-resolution snapshots of the channels in action, revealing how, and how fast, individual K+ ions pass through1,2. It's a remarkable feat - the K+ channel's aperture is more than a hundred thousand times thinner than a sheet of paper, at under six Angstroms wide. 1.Morais-Cabral, J. H., Zhou, Y. & MacKinnon, R. Energetic optimisation of ion conduction rate by the K+ selectivity filter. Nature, 414, 37 - 42, (2001). 2.Zhou, Y., Morais-Cabral, J. H., Kaufman, A. & MacKinnon, R. Chemistry of ion hydration and coordination revealed by a K+ channel-Fab complex at 2.0 A resolution. Nature, 414, 43 - 48, (2001). 3.Doyle, D. A. et al. The structure of the potassium channel: molecular basis of K+ conduction and selectivity. Science, 280, 69 - 77, (1998). © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Biomechanics
Link ID: 889 - Posted: 11.01.2001

Drug users who inject heroin after completing 21-day methadone programs or after release from jail or prison may have a high risk of overdose, according to UCSF researchers. The researchers explained that lowered tolerance levels in each of these situations may increase overdose risk. Researchers with the Urban Health study in the UCSF Department of Family and Community Medicine and the Institute for Health Policy Studies also noted that among heroin injectors, the use of substances such as sedatives and alcohol that contribute to central nervous system depression may promote high risk injection behavior and enhance the respiratory depressant effects of heroin.

Keyword: Drug Abuse
Link ID: 888 - Posted: 11.01.2001

Neuroscientist shares prize with university colleague from Berkeley NEW YORK, October 30, 2001 - The Ameritec Foundation has selected Professor Marie T. Filbin of Hunter College of the City University of New York as co-recipient of the 2001 Ameritec Prize for significant accomplishment toward a cure for paralysis. Director of the college's Specialized Neuroscience Research program, Professor Filbin-the first female winner-shares the prize with Professor Mu-Ming Poo of the University of California at Berkeley. Their research, conducted independently, relates to the role played by a molecule called cyclic AMP in affecting the regeneration of nerve axons after injury. Both scientists will receive the prize at the Neurotrauma Symposium in San Diego on November 10, 2001.

Keyword: Regeneration
Link ID: 884 - Posted: 10.31.2001

By CLAUDIA DREIFUS On a warm recent afternoon, the conservative author and social critic Dr. John H. McWhorter, 36, was sitting in a New York sushi parlor, discussing his other profession: linguistics professor at the University of California at Berkeley with an expertise in language change and evolution. Dr. McWhorter had come to New York from his home base in Oakland, Calif., to attend a meeting at the Manhattan Institute and to put the final touches on his sixth book, a meditation on the natural history of language. The work, "The Power of Babel," is to be issued in January. "Languages have been a passion since I was a small child," he said. "I used to teach them to myself as a hobby. I speak three and a bit of Japanese, and can read seven." Copyright 2001 The New York Times Company

Keyword: Language; Evolution
Link ID: 881 - Posted: 10.31.2001

Army ants team little with large to lift heavy loads. JOHN WHITFIELD If you can't see the point of the miniature back wheel on a penny-farthing bicycle, try riding a unicycle or watch an ant colony. Ants have realized that, to carry a heavy load, two supports are better than one - even if they seem comically mismatched. When army ants partner up to carry a lump of food too big for a single ant to transport, an unusually large worker ant takes the front, and an unusually small one, the back. 1.Franks, N. R., Sendova-Franks, A. B. & Anderson, C. Division of labout within teams of New World and Old World army ants. Animal Behaviour, 62, 635 - 642, (2001). © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Evolution
Link ID: 877 - Posted: 10.30.2001

COLUMBUS, Ohio -- Engaging in stressful tasks like trying to meet a deadline may strengthen the immune system while exposure to stress that must be endured passively - like watching violence on TV - may weaken it, a researcher at the Ohio State University says. The conclusion is based on a study that was designed to draw out the different effects that active and passive coping might have on the body's defenses. It presents some of the strongest evidence yet that certain kinds of stress can promote good health.

Keyword: Stress
Link ID: 876 - Posted: 10.30.2001

The Daily Press Public awareness of brain injury is very low, so this is the perfect time to get information out about this "silent epidemic." According to a recent Harris poll, one in three people are unfamiliar with the term brain injury and over 50 percent believe that HIV/AIDS and spinal cord injury occur more frequently than brain injury. Figures from the Centers for Disease Control (CDC) show there are 1.5 million new brain injuries each year while there are 11,000 spinal cord injuries and 43,000 new cases of AIDS annually.

Keyword: Miscellaneous
Link ID: 875 - Posted: 10.30.2001

By GREG KLINE © 2001 THE NEWS-GAZETTE Published Online October 29, 2001 Some Alzheimer's treatments target a protein that appears to impair brain activity related to learning and memory. Some nerve gases target the same protein, essentially to send the brain, and the body with it, into overdrive and then spiraling out of control. Little wonder then that both national health and defense officials are interested in new University of Illinois research that sheds more light on the workings of the protein acetylcholingsterase, or AChE, by looking at what it does in the brain of a bee.

Keyword: Learning & Memory; Alzheimers
Link ID: 874 - Posted: 10.30.2001

By Judith Blake Seattle Times staff reporter It's been 40 years since a small group of grieving but resolute parents in Washington banded together to fight sudden infant death syndrome, yet SIDS remains in some ways a mystery, its cause unknown. Even so, partly through their work and that of many others, death rates from SIDS have fallen dramatically since then, and scientists are learning more every day about ways to thwart this cruel killer of sleeping babies. Copyright © 2001 The Seattle Times Company

Keyword: Development of the Brain
Link ID: 873 - Posted: 10.30.2001