By Jocelyn Selim An expanding waistline may have less to with what a person eats than what’s already inside, say microbiologists Jeffrey Gordon and Fredrik Backhed at the Washington University School of Medicine in Saint Louis. Variations in the population of bacteria living in the gut may explain why some people pack on extra pounds while others stay slim. Gordon and Backhed base their claim on a study of two groups of mice, one exposed to normal intestinal microbes and another raised in a germ-free bubble. The germ-free mice had 42 percent less body fat, even though they were fed one-third more calories. When the animals were inoculated with bacteria from their normal counterparts, the bubble mice increased their body fat by 57 percent in just two weeks. “We know that gut microbes have ways of breaking down otherwise indigestible carbohydrates, increasing the calories available to the animal, but we thought something else must be at work,” Gordon says. His team therefore also looked at a hormone that limits fat storage in the body. They found that the gut bacteria secrete a substance that interferes with the hormone, causing even more of the calories to be stored as fat than would happen normally. The result is that microbe-containing mice pork up, even on a moderate diet. © 2004 The Walt Disney Company.

Keyword: Obesity
Link ID: 7353 - Posted: 06.24.2010

Those with the genetic condition Down syndrome often suffer a spectrum of problems, such as mental retardation. Their burden, however, may become lighter in the future thanks to increasing research. Some of the research links Down syndrome with Alzheimer’s disease, a memory-robbing brain disorder. Based on this connection, scientists have started testing therapies in people with Down syndrome that have benefited patients with Alzheimer’s disease. Circa 1920s, a diagnosis of Down syndrome was particularly heart crushing. Babies born with the condition often died during childhood. Down syndrome (DS), known for causing delays in intellectual development, also can be associated with serious health conditions, like heart problems. These troubles may turn life-threatening, especially when undertreated. Today, however, factors including changes in attitudes toward DS and more aggressive medical practices mean that the approximately 350,000 Americans living with the condition can expect to reach age 50 and beyond. What’s more, although individuals with DS currently still face a spectrum of obstacles, such as mental retardation, a growing amount of research may help further lighten their burden in the future. Much of the progress hinges on recent studies that link DS with Alzheimer’s disease, a memory-robbing brain disorder. Copyright © 2005 Society for Neuroscience

Keyword: Development of the Brain
Link ID: 7352 - Posted: 06.24.2010

Preliminary findings from a study of children with attention deficit hyperactivity disorder (ADHD) show that sensory intervention -- for example, deep pressure and strenuous exercise -- can significantly improve problem behaviors such as restlessness, impulsivity and hyperactivity. Of the children receiving occupational therapy, 95 percent improved. This is the first study of this size on sensory intervention for ADHD. The Temple University researchers, Kristie Koenig, Ph.D., OTR/L, and Moya Kinnealey, Ph.D., OTR/L, wanted to determine whether ADHD problem behaviors would decrease if underlying sensory and neurological issues were addressed with occupational therapy. Their study, "Comparative Outcomes of Children with ADHD: Treatment Versus Delayed Treatment Control Condition," will be presented Friday, May 13, at the American Occupational Therapy Association meeting in Long Beach, Calif. Children with ADHD have difficulty paying attention and controlling their behavior. Experts are uncertain about the exact cause of ADHD, but believe there are both genetic and biological components. Treatment typically consists of medication, behavior therapy or a combination of the two. "Many children with ADHD also suffer from sensory processing disorder, a neurological underpinning that contributes to their ability to pay attention or focus," explained Koenig. "They either withdraw from or seek out sensory stimulation like movement, sound, light and touch. This translates into troublesome behaviors at school and home."

Keyword: ADHD
Link ID: 7351 - Posted: 05.14.2005

Sid Perkins The aggressor swoops low over the treetops, piercing the night with a barrage of sonar pulses and searching for telltale data bouncing back. Some prospective targets perceive the ultrasound, take evasive action, and escape. Others, the unwary ones, are fair game. When the prowling aerialist senses the faint echoes bouncing off one of these prey, he turns toward the target, quickens his chirp rate, and homes in for the kill. This isn't a duel between modern fighter pilots, but an aerial battle that's been raging nightly for millions of years. It's bat versus insect. Bats are members of one of the most diverse groups of mammals, and the echolocation capability that enables some bat species to detect, track, and catch insects on the wing—even ones as small as mosquitoes—is a crucial part of bats' success. Sonar use has evolved independently among widely disparate groups of creatures. For aquatic mammals, such as porpoises and whales, the sequence of adaptations that led to echolocation is well preserved in the fossil record of their ancestors. But no such trail exists for bats, a group whose oldest known remains indicate that echolocation was already in use. In the handful of bird species that use sonar, the origin of that ability is even murkier. Some echolocating species have close relatives that apparently possess the anatomical means to echolocate but don't use it, implying that avian echolocation is a behavior that some species simply haven't learned. For insights into how echolocation evolved in birds and bats, scientists are turning to DNA, a modern source of information about ancient biological relationships. Copyright ©2005 Science Service.

Keyword: Hearing; Evolution
Link ID: 7350 - Posted: 06.24.2010

BERKELEY, CA – Researchers at the Department of Energy's Lawrence Berkeley National Laboratory have discovered an unsuspected subunit of the protein complex gamma-secretase, which plays a central role in Alzheimer's disease. The researchers have shown that the newly discovered component, the protein CD147, regulates the production of the toxic peptides that cause amyloid plaques, the brain lesions that are the defining feature of Alzheimer's. The role of the gamma-secretase complex in the amyloid-plaque formation pathway: after beta-secretase cleaves APP, the beta segment may be cleaved again by gamma-secretase acting inside the cell membrane, resulting in the formation of amyloid beta-peptides that exit the cell and instigate the formation of amyloid plaques in the brain. However, a newly discovered subunit of gamma-secretase, CD147, normally down-regulates the production of amyloid beta-peptides. "Alzheimer's is worse than a disease — it takes the soul of a human being," says Bing Jap of Berkeley Lab's Life Sciences Division, in whose laboratory the new component was identified. "As the population of this country ages, the incidence of Alzheimer's is increasing, at a terrible increase in cost to society. Research leading to prevention or treatment is urgent." The discovery and role of CD147 as a subunit of gamma-secretase by Jap and his colleagues Shuxia Zhou, Hua Zhou, and Peter Walian is reported in Proceedings of the National Academy of Sciences, in an article now in the online early edition of PNAS at http://www.pnas.org/cgi/content/abstract/0502768102v1?etoc.

Keyword: Alzheimers
Link ID: 7349 - Posted: 06.24.2010

By Denise Winterman It's 70 years since two "hopeless drunks" set up a group dedicated to helping others beat the bottle. Alcoholics Anonymous has become a global institution, although its message is not to everyone's taste. Even Alcoholics Anonymous describes its two founders as "hopeless" drunks. New York stockbroker Bill Wilson and Ohio surgeon Bob Smith were both battling the bottle when they met through a church group in 1935. After fighting his own addiction, Wilson helped Smith kick his, and together they devised the now famous 12-step programme that is the foundation of AA's approach. With a strong spiritual message, it asks people to acknowledge their powerlessness over alcohol, turn to a higher power - whatever they believe that to be - and take specific steps to change. AA is not without it critics, some of whom have likened it to a cult, but few argue that it hasn't helped millions of alcoholics worldwide. So is it the answer to the battle with the bottle? (C)BBC

Keyword: Drug Abuse
Link ID: 7348 - Posted: 05.13.2005

By Dr David Whitehouse Increased solar activity causing disturbances in the Earth's magnetic field may cause whales to run aground in the North Sea, say researchers. Analysis of whales stranded between 1712 and 2003 shows that more are stranded when solar activity is high. Writing in the Journal of Sea Research, scientists propose that whales use the Earth's magnetic field to assist navigation like homing pigeons do. As the Sun disrupts the magnetic field whales can become confused, they say. The Sun goes through a cycle with an average length of about 11 years, though individual cycle lengths have ranged from 8 to 17 years. Some evidence exists that shorter cycles produce a higher flux of radiation from the Sun. Dr Klaus Vaneslow and colleagues from the University of Kiel have analysed the lengths of solar cycles and find that 87 of the 97 reported sperm whale strandings over the past 300 years in the North Sea region occurred when the length of the Sun's activity cycle was below average. They argue that whales may be like pigeons and dolphins in having a magnetic sense based on small crystals of magnetite found in certain cells. Pigeons use such cells to sense the Earth's magnetic field to help in their navigation. Pigeon enthusiasts are well aware that the birds can go astray during times of high solar activity, when disturbances in the magnetic field confuse them. (C)BBC

Keyword: Animal Migration
Link ID: 7347 - Posted: 05.13.2005

David Perlman, Chronicle Science Editor Consider the waggle dance of the honeybee, famed in science and controversial for nearly 50 years. Most scientists firmly believe the dance is a mysterious coded language that the bees use to direct their hive-mates how to fly toward distant food sources of nectar and pollen. Its insight as "language" won its German discoverer a Nobel Prize in 1973. Scores of experiments over the decades have claimed to support his theory. But UC Santa Barbara biologist Adrian Wenner, who has been a beekeeper in the Sacramento Valley since childhood, insists that it is just the scent of food that sends the honeybees flying in flocks -- and that scientists who believe in the language of the honeybee dance are merely "suckers for the exotic" whose experiments are designed to support the theory and not to challenge it. Now, a group of researchers, led by a British physicist who tagged three dozen bees with radar transponders to track their flight, claims their experiments confirm that the dance is "the most sophisticated example of non- primate communication that we know of." The latest effort to decipher the honeybee's "waggle dance" is being published today in the journal Nature by Joseph R. Riley of Britain's Rothamsted Research Center in rural Hertfordshire, together with Uwe Greggers of Berlin's Free University and other colleagues. ©2005 San Francisco Chronicle

Keyword: Animal Communication
Link ID: 7346 - Posted: 06.24.2010

COLUMBUS , Ohio –- The brains of one species of mouse actually shrink during the winter, causing the mice to have more difficulty with some types of learning, a new study found. The results showed that, during the short days of winter, white-footed mice had impaired spatial memory – the mental map that helps them remember important places in their environment. This is one of the first studies to show seasonal changes in the structure and the functioning of brains of mammals, said Randy Nelson, co-author of the study and professor of psychology and neuroscience at Ohio State University. The changes in the brain may help the mice conserve energy to survive during the cold winter season when food is scarce and conditions are harsh. “The brain uses a lot of energy relative to its weight,” Nelson said. “Like many mammals, mice need to reduce their energy costs during winter, and the brain is a good place to do that.” And while there are obviously many differences between mice and humans, studies like this may one day help researchers gain insight into seasonal brain dysfunctions in humans such as seasonal affective disorder, Nelson said. Nelson conducted the study with Leah Pyter, a graduate student in neuroscience at Ohio State , and Brenda Reader, an undergraduate psychology major at Ohio State . The findings were published in the May 4 issue of the Journal of Neuroscience.

Keyword: Biological Rhythms; Learning & Memory
Link ID: 7345 - Posted: 06.24.2010

For some kinds of birds, learning to sing is as much a part of growing up as learning to talk is for human children. They listen to their parents and other adults, memorize, imitate, practice, and in time are able to chirp a tune characteristic of their species that will help attract a mate. Now Rockefeller University scientists have found that young canaries can learn to accurately imitate a computer-generated song that sounds nothing like a canary. But as the birds mature, they edit their song, dropping some elements, rearranging others, and adding repetitions and phrasing typical of an adult canary melody. The results appear in the May 13 issue of Science. "This kind of reprogramming is reminiscent of the flexibility of phoneme rearrangement in human speech and is an aspect of vocal prowess in birds that had not been described before," says Fernando Nottebohm, Ph.D., Rockefeller's Dorothea L. Leonhardt Professor and head of the Laboratory of Animal Behavior. Young canaries normally learn their songs by closely copying a nearby adult, a process that takes six to eight months. However, even birds raised without a singing tutor develop a song with canary-like syllables and phrasing. Under those conditions the juveniles are thought to be guided by an innate program that leads to the development of normal adult song.

Keyword: Language
Link ID: 7344 - Posted: 05.13.2005

— Box jellyfish, which have no brain and only a basic nervous system, are enjoying newfound evolutionary status with research revealing they have surprisingly sophisticated eyes. And it appears Australian jellyfish may have the most sophisticated visual systems of all. Researchers from Lund University in Sweden studied a small Caribbean species of jellyfish, Tripedalia cystophora, found in mangrove swamps in Puerto Rico. They report in the current issue of the journal Nature that the jellyfish boast impressive optical apparatus: a total of 24 eyes clustered at each of the creature's four corners. While 16 eyes are simple "pigment pits" to collect light, the remaining eight, a pair in each eye cluster, have complex lenses. Despite this complexity, the position of the retinas means the images the jellyfish receive are blurred. But researchers believe the sophisticated optical set-up is designed to give jellyfish a wide field of vision to help them navigate, rather than to focus on prey. Copyright © 2005 Discovery Communications Inc.

Keyword: Vision; Evolution
Link ID: 7343 - Posted: 06.24.2010

Cocaine abuse is becoming increasingly prevalent among women of childbearing age, and is associated with numerous adverse perinatal outcomes. New research, published in The Journal of Physiology, by Professor Lubo Zhang and his research team from Loma Linda University School of Medicine in California presents the exciting novel finding that cocaine exposure in utero has lasting and lifelong adverse effects on the heart in adulthood, particularly if you are male! Professor Zhang's research group has been studying the effect of adverse intrauterine environment on fetal heart development and its lifelong pathophysiological consequences in the adult heart. Using an animal model of the pregnant rat, they found that fetal exposure to cocaine during gestation resulted in an increase in heart susceptibility to ischaemia and reperfusion injury in late adult life. Interestingly, the effect of prenatal cocaine exposure on cardiac vulnerability in adult offspring is gender-dependent, with the male heart being more susceptible to increased ischaemia/reperfusion injury induced by prenatal cocaine exposure. Earlier work by professor Zhang's group showed that fetal chronic hypoxia also increased cardiac vulnerability to ischaemia and reperfusion injury in late adult life. Epidemiological studies in humans have shown an association of fetal undernutrition in the womb and an increased risk of hypertension and ischaemic heart disease in adulthood.

Keyword: Drug Abuse; Development of the Brain
Link ID: 7342 - Posted: 05.13.2005

Pamela Fayerman, Pregnant women alert: if you're being plagued by maternal forgetfulness, blame it on your unborn daughters. A new Simon Fraser University study, to be published Thursday in NeuroReport, is the first to show that women carrying male fetuses consistently do better on the hardest memory function tests than women pregnant with girls. "Dumb-mom syndrome" -- as the cognitively compromised state has been jokingly named -- was the focus of an 18-month study by SFU psychology department researchers trying to find out whether pregnancy changed cognition. "We were quite shocked by the results because when we began, we weren't thinking about fetal sex as being a factor," said study co-author Neil Watson, a professor who specializes in neuroscientific research. Watson and co-investigator, PhD candidate Claire Vanston, enrolled 43 Vancouver-area women into the study, subjecting them to a battery of cognition tests from early in their pregnancies to several months after they gave birth. They found that while there was no difference in general intellect between women bearing boys and those with girls, the former group outperformed the latter in tasks involving certain aspects of short-term memory. Watson said in an interview that previous studies have delved into whether attention, concentration and memory are as impaired in pregnancy as anecdotal reports have suggested. But such studies have yielded inconsistent results. Those that did find cognition impacts attributed them to fluctuations in female hormones that steadily increase throughout pregnancy. Copyright © 2005 CanWest Interactive Inc.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 7341 - Posted: 06.24.2010

St. Paul, Minn. – People with very mild Alzheimer’s disease are still competent to make decisions about their treatment, while those with moderate Alzheimer’s may no longer be able to competently make those decisions, according to a study published in the May 10 issue of Neurology, the scientific journal of the American Academy of Neurology. The study also found that people who were aware of their Alzheimer’s diagnosis, symptoms, and prognosis were more likely to be able to make competent decisions, regardless of the severity of their disease. “These results are yet another reason why people should consult a doctor if they notice any warning signs of Alzheimer’s in themselves or a loved one,” said study author Jason Karlawish, MD, of the University of Pennsylvania in Philadelphia. “An early diagnosis can help assure that patients can participate in decisions about their care.” For the study, researchers interviewed 48 people with very mild to moderate Alzheimer’s disease and 102 caregivers of people with mild to severe Alzheimer’s. The patients’ decision-making abilities were measured by giving them information about the benefits and risks of a hypothetical treatment for Alzheimer’s and asking them to make a choice whether they would take the treatment. Then experts assessed whether they were competent to make the decision. Of the 48 patients, 19 were found to be competent in making the decision.

Keyword: Alzheimers
Link ID: 7340 - Posted: 06.24.2010

US scientists have invented a pill that can boost memory. The drug CX717 belongs to a family of compounds called ampakines and works by boosting the brain chemical glutamate that makes learning and recall easy. UK trials on 16 sleep-deprived volunteers showed it improved wakefulness and mental ability. Its creator, Dr Gary Lynch from the University of California, told New Scientist it could be used to treat jet lag and diseases like Alzheimer's. Manufacturer Cortex is considering CX717 as a possible treatment for narcolepsy - excessive daytime sleepiness - and attention deficit hyperactivity disorder (ADHD) - a condition which impairs a child's ability to concentrate. It could also be taken by healthy people as a pick-me-up. But it will have to undergo further clinical trials before going on sale. Dr Lynch explained how the drug works. "What it's doing is causing the neurons to communicate with each other a little better. "As you get tired, communication between brain cells begins to fail. When you take the pill, the communication is better." He said the drug appeared to have no side effects and because it was not a physical stimulant, like amphetamines, users would still be able to sleep. In the UK trial, led by Julia Boyle and colleagues from the University of Surrey, healthy male volunteers aged 18 to 45 agreed to test the drug. The volunteers started with a full night's sleep and the following morning and evening were asked to complete a battery of tests assessing memory, attention, alertness, reaction time and problem solving. At 11pm they took either the real or dummy pills and stayed up through the night, being retested at midnight, 1am, 3am, 5am and 9am. (C)BBC

Keyword: Learning & Memory
Link ID: 7339 - Posted: 05.12.2005

By Marc Kaufman Soon after the Food and Drug Administration overruled its advisory panel last year and rejected an application to make an emergency contraceptive more easily available, critics of the agency said it had ignored scientific evidence and yielded to pressure from social conservatives. The agency denied the charge, but an outspoken evangelical conservative doctor on the panel subsequently acknowledged in a previously unreported public sermon that he was asked to write a memo to the FDA commissioner soon after the panel voted 23 to 4 in favor of over-the-counter sales of the contraceptive, called Plan B. He said he believes his memo played a central role in the rejection of that recommendation. The new information comes from a videotaped sermon in October by W. David Hager. On the tape, he said he was asked to write a "minority report" that would outline why over-the-counter sales should be rejected. Speaking at the Asbury College chapel in Wilmore, Ky., Hager said, "I was asked to write a minority opinion that was sent to the commissioner of the FDA. For only the second time in five decades, the FDA did not abide by its advisory committee opinion, and the measure was rejected." © 2005 The Washington Post Company

Keyword: Sexual Behavior
Link ID: 7338 - Posted: 06.24.2010

Radar has helped resolve a long-standing controversy about the purpose of a strange dance performed by bees, Nature magazine reports. The famous "waggle" dance contains information about the whereabouts of nectar, just as was originally proposed in the 1960s, scientists now claim. The theory met with scepticism, partly because people did not believe bees could decode such a complex message. But now radar tracking has proved they do follow waggle dance instructions. Bee-keepers have long puzzled over the mysterious little performance, which bees stage for their hive-mates when they return home from a foraging mission. On entering the hive after gathering nectar, a bee will run around in a tight figure of eight dance, waggling its abdomen as it does so. All the other bees gather around, apparently scrutinising the ceremonial manoeuvre. "It is, at first sight, a rather confusing and not very organised movement," said co-author Joe Riley of Rothamsted Research, UK. "But if you watch it carefully you can recognise the very distinct and organised pattern." It wasn't until the 1960s that a plausible explanation for the dance was proposed, by Nobel Prize winning zoologist Karl von Frisch. He suggested that the bees are delivering a complex set of instructions about how to find a rich nectar source. The direction the bees point while performing the dance, Professor von Frisch speculated, indicates the direction of the food source in relation to the Sun; while the intensity of the waggles indicate how far away it is. (C)BBC

Keyword: Animal Communication; Language
Link ID: 7337 - Posted: 05.12.2005

As far back as the American Civil War doctors have documented cases where patients seemed to experience phantom pains in an uninjured arm or leg after suffering an injury to their opposite limb. While working to understand the biological causes of chronic pain, neurologist Anne Louise Oaklander became curious about these types of phantom pain, having heard surprising complaints from some of her patients. "I had a number of patients who mentioned to me that they had symptoms of injury in the opposite limb, as well as in the injured limb," explains Oaklander, MD, director of the Nerve Injury Unit at Massachusetts General Hospital in Boston. Oaklander's research group has shown that the so-called "mirror-image pain" can't be simply explained away by overuse of the uninjured limb, or as psychological. "These seemingly bizarre complaints have contributed to the impression that some chronic pain patients are crazy," she says. But, studying mirror-image pain in patients suffering from shingles – a condition caused by the virus that produces chicken pox in children, which inflicts adults with a painful rash or blisters on one side of the body – she showed that the answer is even more of a mystery – nerve damage on one side can actually lead to "crossover" nerve damage in the exact same spot on the opposite side of the body. "Many people interpreted our shingles study as due to just the virus getting into the spinal chord and traveling over to the opposite side of the body, and that certainly is a reasonable interpretation, and the most obvious one," Oaklander says. But she had seen this crossover effect in patients with all kinds of injures, such as cut fingers, sprained ankles and broken legs. So she went on to study the mirror-pain related to direct injuries where no viruses were involved. (C) ScienCentral, 2000-2005.

Keyword: Pain & Touch
Link ID: 7336 - Posted: 06.24.2010

An understanding of exactly how the brain controls breathing is fundamental to the treatment of respiratory disorders. We know that breathing is an automatic rhythmic process that persists without conscious effort whether we are awake or asleep, but the question that has intrigued many scientists for well over 100 years is what maintains this almost fail safe vital rhythm throughout life? Experimental Physiology editor Julian Paton invited two world renowned scientists Dr. Guyenet from the University of Charlottesville and Dr. Richerson from Yale University, to use the journal as a forum to discuss the issue and attempt to resolve their differences in opinion. Both authors agree that the respiratory rhythm requires specialised nerve cells (central chemoreceptors) to power the rhythm, but the issue highly debated by Guyenet and Richerson is the precise location and cell types involved. Guyenet proposes that these nerve cells are located in a ventral area of the brainstem (the retrofacial region) and loaded with a transmitter substance called glutamate. Their close proximity to the ventral surface of the brain allows them to sense and react to changes in the pH of the cerebrospinal fluid; this is deemed an essential property of a central chemoreceptor. Richerson, on the other hand, stipulates that central chemoreceptors are found close to the midline blood vessels of the brainstem allowing them to 'taste' the pH of the blood. His cells do not contain glutamate but a substance called serotonin.

Keyword: Miscellaneous
Link ID: 7335 - Posted: 05.12.2005

Michael Hopkin The season in which a woman is born influences the age at which she will go through the menopause, suggests a survey of northern Italians. The survey, which looked at nearly 3,000 post-menopausal women at three clinics, revealed that those born in March showed the earliest menopause, at an average age of 48.9 years. At the other end of the scale, those born in October remained fertile until an average age of 50.3, with many lasting beyond 55. The difference may arise because spring babies tend to be born with a smaller stash of eggs in their ovaries, suggests Angelo Cagnacci of the Modena General Hospital, who led the study. They might therefore run out earlier in life, leading to an earlier menopause. Cagnacci's team quizzed the women on the age at which they entered menopause, and a suite of other factors thought to influence menopause timing: the age at which they first became fertile, whether they ever smoked, their education level and their type of employment. After accounting for these differences, a clear seasonal pattern emerged, the team reports in the journal Human Reproduction1. Previous studies have shown other differences based on time of birth. Babies born in autumn tend to be heavier, for example, and to live longer. ©2005 Nature Publishing Group

Keyword: Biological Rhythms; Sexual Behavior
Link ID: 7334 - Posted: 06.24.2010