By LAWRENCE K. ALTMAN BARCELONA, Spain, — The vast majority of young gay and bisexual men in the United States who were found to have the AIDS virus in a new study were unaware of their infection, according to findings reported as the 14th International AIDS Conference opened here today. The rates of unawareness among minority gay men ages 15 to 29 in the study were staggeringly high. Among those found to have H.I.V., the AIDS virus, 90 percent of blacks, 70 percent of Hispanics and 60 percent of whites said they did not know they were infected. Most of these infected men perceived themselves to be at low risk of being infected, despite having engaged in frequent high-risk sex like unprotected anal intercourse, said Duncan MacKellar, an epidemiologist from the federal Centers for Disease Control and Prevention in Atlanta, which conducted the study. Copyright 2002 The New York Times Company

Keyword: Sexual Behavior
Link ID: 2292 - Posted: 06.24.2010

By CARLA BARANAUCKAS Dr. W. Maxwell Cowan, an internationally known neurobiologist and a retired vice president of the Howard Hughes Medical Institute, died June 30 at his home in Rockville, Md. He was 70. The cause was prostate cancer, said the Robert A. Pumphrey Funeral Home in Bethesda, Md. As the chief scientific officer of the Hughes Institute, Dr. Cowan played a central role in determining how millions of dollars for biomedical research was directed from 1987 to 2000. The institute, which was founded by Howard Hughes and has an endowment of about $11 billion, employs about 350 university scientists known as Hughes investigators and finances their research. Copyright 2002 The New York Times Company

Keyword: Miscellaneous
Link ID: 2291 - Posted: 07.08.2002

The Dynamic Brain Atlas could be a giant leap forward for neuroscience BY THOMAS K. GROSE When a doctor looks at a patient's brain scan, some problems are immediately clear. Tumors, for instance, aren't easily hidden. Other subtle abnormalities are harder to detect, however. So for years, doctors have relied on brain atlases — compendiums of scans of normal brains in book form — to make comparisons and spot differences. But book atlases are far from infallible. "The traditional atlas is an extrapolation of the general population," explains Jo Hajnal, a physicist at the MRC Clinical Services Centre at London's Imperial College. "They contain only whatever the preparer thought was useful," he adds. Now computer technology is giving physicians a much more powerful diagnostic tool: brain atlas images customized to each patient. Hajnal is part of a team of researchers at Imperial College and King's College London that has devised a Dynamic Brain Atlas, which runs from a networked laptop. The current prototype can access hundreds of images stored in databases around the world and create a composite image that closely approximates each patient's brain. Copyright © 2002 Time Inc. All rights reserved.

Keyword: Brain imaging
Link ID: 2290 - Posted: 06.24.2010

By Georgina Kenyon Tracey Sullivan, 30 of Kew, London always feels terrible in the mornings. She has done ever since she was a teenager. At least she did until she started sleeping every second night. "I think I've cracked it. All this time I think I have been running on a 48 hour clock," she claimed. Chronic tiredness is a common problem, especially among the over-worked in London. But most people believe they need more sleep, not less. "When I tried to sleep properly each night, about six or seven hours, I could never wake up properly. When the alarm went off at 7am, I could hardly drag myself to work each day and I would not wake up totally until late afternoon," said Tracey. (C) BBC

Keyword: Sleep
Link ID: 2289 - Posted: 07.07.2002

A study of African tribes found that the one with a fish-based diet had lower levels of a hormone which influences appetite. It suggests that people eating a fish-rich diet may find it easier to control their appetite - and perhaps their weight. The tribes came from neighbouring regions, and ate a diet with the same number of calories - but composed of different types of food. One was predominantly fish-based, while the other ate a vegetarian diet. Researchers, from the Mayo Clinic in Rochester, Minnesota, looked at the levels of a hormone called leptin in men and women. This hormone is produced by fat cells, and its role, in people with normal weight, is to tell people when they have had enough food. (C) BBC

Keyword: Obesity
Link ID: 2288 - Posted: 07.07.2002

Scientists have stumbled on a secret weapon against snails and slugs. They have discovered the garden pests are poisoned by caffeine. A strong cup of coffee is enough to send the creatures into a writhing frenzy, followed soon by death. Scientists think caffeine acts as a potent neurotoxin against the pests. The finding may be of use to gardeners and commercial growers. Slugs and snails are notoriously difficult to deter from attacking plants. The chemicals currently used to control them are not permitted as residues on food crops. (C) BBC

Keyword: Neurotoxins
Link ID: 2287 - Posted: 07.07.2002

Workaholics, take note: new research indicates that morning sleep and afternoon naps aid mental and physical learning. Scientists have known for some time that sleep can improve the brain’s acquisition of new facts and skills, but its effect on previously learned knowledge was not known. To that end, two studies published this month in the journals Neuron and Nature Neuroscience suggest that snoozing can reverse "burnout" from information overload and improve motor skill development. In the first study, Sara Mednick of Harvard University and her colleagues investigated the role of sleep in perceptual learning by training subjects to report the direction of colored bars superimposed on other lines on a computer screen. Their performance progressively worsened throughout the day. If the researchers allowed individuals to nap for 30 minutes, however, the deterioration halted; a one-hour snooze enabled performance to bounce back to initial morning levels. © 1996-2002 Scientific American, Inc. All rights reserved.

Keyword: Sleep; Learning & Memory
Link ID: 2286 - Posted: 06.24.2010

By GINA KOLATA IT seems a fairly obvious idea: when science experiments are successful, the results are published in a well-respected journal for all to see and the body of human knowledge expands. But the sad truth about science is that most experiments fail and the hypotheses that seduced researchers turn out not to be true or, at least, the studies provide no evidence that they are true. Are such studies any less important, any less successful? And what happens to them? Generally, if the negative studies are large and the hypotheses well known, they will be published. That happened, for example, with studies of thousands of cellphone users finding no evidence that cellphone radiation predisposes to brain cancer. It also happened with a study published last month finding no evidence that men who had vasectomies are more likely to get prostate cancer. Copyright 2002 The New York Times Company

Keyword: Miscellaneous
Link ID: 2285 - Posted: 07.07.2002

Our bodies may look symmetric from the outside, but inside, organs such as the heart or the liver are tucked or oriented to the left or right. New research suggests that fluid driven by tiny swirling hairs called cilia may activate certain genes in the growing embryo that lay the groundwork for this asymmetry. Based on experiments with mice, some scientists had speculated that cilia nestled in a dimple at the top of the embryo called the node might push fluid down the left side of the embryo, carrying a signal that somehow triggers certain genes to activate. Other scientists doubted the idea. The new experiments suggest that the cilia-driven flow is indeed important. Researchers led by developmental biologist Hiroshi Hamada at the University of Osaka used a pump to reverse the normal leftward flow of fluid over mouse embryos. This caused two key genes normally activated solely on the left side of the body to be expressed on the right side, the team reports in the 4 July issue of Nature. Copyright © 2002 by the American Association for the Advancement of Science.

Keyword: Laterality; Development of the Brain
Link ID: 2284 - Posted: 06.24.2010

Hormone links obesity and insulin resistance in mice, but doubts persist about impact on type 2 diabetes research By Eugene Russo Diabetes researchers have long known about the connection between obesity and insulin resistance, but they have yet to identify the hormonal machinery responsible for that connection. In this Hot Paper, published 18 months ago, investigators appeared to have uncovered a major part of that machinery when they discovered the resistin hormone in mice.1 More recent findings, however, have cast doubt on resistin's relevance in human diabetes. Senior author Mitchell Lazar, director of the University of Pennsylvania Diabetes Center, notes two major factors that helped lead his group to discover resistin. First, based on findings related to leptin, the now infamous hormonal fat-regulator, Lazar knew that fat not only serves to store energy, but also helps communicate with other tissues. Leptin, and other fat-secreted molecules, are proof that fat cells make unique signaling molecules that communicate with other parts of the body. 1. C.M. Steppan et al., "The hormone resistin links obesity to diabetes," Nature, 409:307-12, Jan.18, 2001. The Scientist 16[14]:39, Jul. 8, 2002 © Copyright 2002, The Scientist, Inc. All rights reserved.

Keyword: Obesity
Link ID: 2283 - Posted: 06.24.2010

WASHINGTON - New studies reveal that a learned compensatory response can trigger "drug tolerance," a physiological process central to addiction. Drug tolerance makes people need more and more drug to get the same effect, whether pain relief or a "high." Its newly discovered psychological aspect -- in which a drug-predictive cue primes the body to react "as if" the drug effect is imminent -- might be used to treat addiction more effectively. In short, if drug tolerance can be learned, there is a chance it can be unlearned, reducing or eliminating the tolerance-related cravings and other withdrawal symptoms that can lead addicts to relapse. The findings appear in the July issue of the Journal of Experimental Psychology: Animal Behavior Processes , which is published by the American Psychological Association (APA). This study used rats, but addiction researchers frequently generalize from rats to humans because "rats, like humans, can become dependent on addictive drugs, and display drug tolerance and drug withdrawal symptoms," says co-author Shepard Siegel, Ph.D., of McMaster University in Hamilton, Ontario. © PsycNET 2002 American Psychological Association

Keyword: Drug Abuse; Learning & Memory
Link ID: 2282 - Posted: 06.24.2010

Scientists have discovered a reason why having sex could be bad for your health.The research reveals that hormones are the key to mating insects having a shorter life expectancy. The findings may also give clues as to why the same principle appears to hold true for other creatures - including humans. Mealworm beetles, more commonly bought as food for pet reptiles and birds, were used in the research by Dr Jens Rolff and Dr Michael Siva-Jothy at the University of Sheffield. A hormone released after mating adversely affected an enzyme vital to keep the immune system functioning. The beetles were therefore more susceptible to infection, and less likely to live as long. (C) BBC

Keyword: Sexual Behavior
Link ID: 2281 - Posted: 07.06.2002

Exclusive from New Scientist Print Edition Drugs such as Viagra should work for some women - especially if they have a big G spot. This spot, famed for producing spectacular orgasms, turns out to be awash with the enzymes that these drugs act on. The term G spot, coined by Ernest Gräfenberg in 1950, refers to an area a few centimetres up inside the vagina on the side closest to a woman's stomach (see diagram). Buried in the flesh here are the Skene's glands, the female equivalent of the prostate gland. In men, the prostate produces the watery component of semen. In women, Skene's glands are also thought to produce a watery substance that may explain female "ejaculation". The tissue surrounding these glands, which includes the part of the clitoris that reaches up inside the vagina, swells with blood during sexual arousal. And there's some evidence that nerves in the area produce an orgasm different to one produced by clitoral stimulation. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 2280 - Posted: 06.24.2010

By Larry O'Hanlon, Discovery News — Lizards, it seems, have a fancy for television, when the programming suits their tastes. Australian biologists have found that male Jacky dragons, Amphibolurus muricatus, can get just as riled by videos of aggressive territorial males as by the real thing. In a test to demonstrate that reptiles can perceive video images similar to the way humans can, male Jacky dragons responded to video lizards as if they were the real things. It opens up doors to more research on how reptiles and other animals communicate with one another, as well as how communication evolved among animals. "It's studying lizards, but it's a model system for how behavior evolved," said animal behavior biologist Terry Ord, who recently moved from Macquarie University, in Australia to Indiana University. Ord and his Macquarie University colleagues published their work in the current issue of the journal Animal Behavior. Copyright © 2002 Discovery Communications Inc

Keyword: Aggression; Sexual Behavior
Link ID: 2279 - Posted: 06.24.2010

By ADAM LIPTAK FORT LAUDERDALE, Fla., — The unsolicited Prozac arrived in a hand-addressed manila envelope. It came from a Walgreens drugstore not far from here, and there was a "Dear Patient" form letter inside. "Enclosed you will find a free one month trial of Prozac Weekly," it said. "Congratulations on being one step to full recovery." The mailing infuriated one recipient, a 59-year-old home caregiver who filed a class-action lawsuit this week in state court here. "They're going after me because I have a problem," said the caregiver, who agreed to an interview in her lawyer's office here on the condition that her name be withheld. Copyright 2002 The New York Times Company

Keyword: Depression
Link ID: 2278 - Posted: 06.24.2010

By YUDHIJIT BHATTACHARJEE In the grand story of evolution that scientists have been reconstructing since Charles Darwin's voyage on H.M.S. Beagle, the chapter on mate selection reads something like this: males compete among themselves to attract females, showing off their antlers, bright plumage or other ornaments that signal good health. Females watch the display from the sidelines, aloof and picky, like wealthy patrons at an art exhibition. When a male meets a female's approval, she agrees to court him and finally grants him permission to impregnate her. That account of mate choice, in which males do all the dancing-to-impress and females sit on the judging panel, is being increasingly viewed by scientists as too simplistic — a broad-brush picture that tells only part of the story. Copyright 2002 The New York Times Company

Keyword: Evolution; Sexual Behavior
Link ID: 2277 - Posted: 06.24.2010

NewScientist.com news service A rapid way to create a 3D map of the brain's genetic activity should help researchers pinpoint the neurological underpinnings of autism, schizophrenia and other brain disorders. Desmond Smith of the University of California, Los Angeles and his colleagues developed the technique called "voxelation" to study Parkinson's disease in a mouse model. "We could see mass migrations of gene activity. It was very dramatic," says Smith. The team found that one group of genes shifted their activity away from the striatum - a region known to be highly disrupted by Parkinson's disease. Their analysis also revealed that genes involved with communication between cells seem to figure prominently in the disease. © Copyright Reed Business Information Ltd.

Keyword: Brain imaging; Genes & Behavior
Link ID: 2276 - Posted: 06.24.2010

WINSTON-SALEM, N.C. – Wake Forest University School of Medicine scientists are closing in on why drinking alcohol before bedtime paradoxically improves sleep that evening, but disrupts sleep during the early morning hours. In a presentation at the Research Society on Alcoholism in San Francisco, Dwayne W. Godwin, Ph.D. explained that a key brain region involved in sleep, the thalamus, is "exquisitely sensitive to alcohol." The cells in the thalamus possess an ion channel that behaves differently depending on the amount of alcohol that has been drunk. "Low doses of alcohol increase activity; high doses shut it down," said Godwin, associate professor of neurobiology and anatomy. Copyright: Wake Forest University School of Medicine

Keyword: Drug Abuse; Sleep
Link ID: 2275 - Posted: 06.24.2010

The skull and jawbone of a small, lightly-built individual, discovered at an archeological site in Dmanisi, Georgia, may call into question the prevailing idea that larger brain size was behind the migration of human ancestors out of Africa. An international research team describes their find in the journal Science, published by the American Association for the Advancement of Science. The scientists found a petite new individual, with a small brain, thin brow ridge, short nose, and huge canine teeth, according to co-author David Lordkipanidze of the Georgian Academy of Sciences, in Tbilisi. This was the third specimen found at the site. By comparison, the other two skulls had room for substantially larger brains. All three specimens are approximately 1.75 million years old, making them the largest collection of individuals from any one site older than around 800,000 years. Lordkipanidze and his colleagues have tentatively concluded that the three belong to the same species, Homo erectus, thought to be the first hominid species to leave Africa. The Dmanisi fossils most closely resemble the African version of Homo erectus, called Homo ergaster.

Keyword: Evolution
Link ID: 2274 - Posted: 07.06.2002

Evidence is mounting that sleep – even a nap – appears to enhance information processing and learning. New experiments by NIMH grantee Alan Hobson, M.D., Robert Stickgold, Ph.D., and colleagues at Harvard University show that a midday snooze reverses information overload and that a 20 percent overnight improvement in learning a motor skill is largely traceable to a late stage of sleep that some early risers might be missing. Overall, their studies suggest that the brain uses a night's sleep to consolidate the memories of habits, actions and skills learned during the day. The bottom line: we should stop feeling guilty about taking that "power nap" at work or catching those extra winks the night before our piano recital. Reporting in the July, 2002 Nature Neuroscience, Sara Mednick, Ph.D., Stickgold and colleagues demonstrate that "burnout" – irritation, frustration and poorer performance on a mental task -- sets in as a day of training wears on. Subjects performed a visual task, reporting the horizontal or vertical orientation of three diagonal bars against a background of horizontal bars in the lower left corner of a computer screen.

Keyword: Sleep
Link ID: 2273 - Posted: 06.24.2010