Roxanne Khamsi For years, experts have feared that thousands of people are unknowingly carrying and transmitting the human form of mad cow disease: new-variant Creutzfeldt-Jakob disease (vCJD). Now a blood test could help to ease their worries, or confirm their worst nightmare. Researchers have succeeded in reliably detecting the malformed proteins that cause vCJD in blood samples taken from hamsters. Their test takes only a few days to complete. If the procedure works as well in humans, it could be used to check stocks in blood banks. At the moment there is no such screening process; two of the people who have died of vCJD in Britain are thought to have picked up the disease from transfusions. If improved, the test might also be used to screen animals for the disease before they enter the food chain. The rare disease is thought to be caused by the formation of abnormal proteins in the brain known as prions. These misshapen proteins apparently multiply by changing the conformation of normal proteins that they come into contact with, eventually leading to a fatal neurodegenerative illness. ©2005 Nature Publishing Group

Keyword: Prions
Link ID: 7810 - Posted: 06.24.2010

KILLER whales and chimpanzees both pass on "traditions" to other members of their group, according to two separate studies of feeding behaviour. The findings add to evidence that cultural learning is widespread among animals. One study involved killer whales at Marineland in Niagara Falls in Ontario, Canada. An inventive male devised a brand new way to catch birds, and passed the strategy on to his tank-mates. The 4-year-old orca lures gulls into his tank by spitting regurgitated fish onto the water's surface. He waits below for a gull to grab the fish, then lunges at it with open jaws. "They are in a way setting a trap," says animal behaviourist Michael Noonan of Canisius College in Buffalo, New York, who made the discovery, "They catch three or four gulls this way some days." “The orca lures gulls into his tank by spitting regurgitated fish into the water. He waits for a bird to grab the fish and then lunges”Noonan had never seen the behaviour before, despite three years of observations for separate experiments. But a few months after the enterprising male started doing it, Noonan spied the whale's younger half-brother doing the same thing. Soon the brothers' mothers were enjoying feathered snacks, as were a 6-month-old calf and an older male. Noonan presented the research this month at the US Animal Behavior Society meeting in Snowbird, Utah. Wild dolphins off the west coast of Australia were the first marine mammals in which cultural learning was observed. They apparently learn from group-mates how to use sponges to protect their snouts while scavenging (New Scientist, 11 June, p 12). But the evidence from killer whales is much more conclusive because the process was observed from start to finish. © Copyright Reed Business Information Ltd.

Keyword: Learning & Memory; Evolution
Link ID: 7809 - Posted: 06.24.2010

By Caroline Ryan "Schizophrenia is the price that homo sapiens pay for language." That is the controversial theory of one leading psychiatrist. Professor Tim Crow believes that the difference in the development of the human brain from the primate brain - which allows us to process thought and speech - is linked to why psychotic illnesses occur. The human brain has developed to have a strong regional bias, so each side of the brain performs certain roles - for example, speech is controlled by the left side of the brain. Professor Crow of the mental health charity Sane's Prince of Wales International Centre in Oxford, suggests the division boundaries between certain areas of the brain, particularly those which are concerned with language and thought, are "blurred" in people with psychoses. People with these conditions may hear their inner thoughts as external voices, or believe thoughts have been inserted in their head, suggesting the normal divisions do not exist. The reason for this, he says, is that their brains do not have the bias, or asymmetry, seen in healthy people. Brain asymmetry means that areas control certain things, so the left-hand side controls language. He said: "Asymmetry appears to be less pronounced in people with psychoses." (C)BBC

Keyword: Schizophrenia; Language
Link ID: 7808 - Posted: 08.27.2005

Scientists have identified a chemical that can sneak through the blood-brain barrier to treat tumours. The barrier exists to prevent toxic substances getting into the brain, which makes it hard to deliver drugs. Researchers found enough of the chemical, JV-1-36, could bypass the guard to block tumour growth. The University of Saint Louis study, in Proceedings of the National Academy of Science, suggests the compound may also be useful in treating other cancers. The team carried out tests on mice who had had malignant glioblastomas, the most common form of brain tumour, implanted. They then gave an intravenous injection of JV-1-36, which inhibits the effect of the hypothalamic growth hormone-releasing hormone (GHRH). GHRH's role should be to trigger the hormone that makes children grow, but it has also been found to fuel the growth of cancerous tumours. Receptors for the hormone have been found in other cancer cells including breast, ovary, prostate, pancreas and colon. The researchers found that the P-gp system, which acts as an extra "security guard" at the blood brain barrier and usually keeps anti-cancer drugs out of the brain, blocked some of the JV-1-36, but let much of it pass into the brain. The researchers say the compounds gets into the brain by dissolving into the cell membranes which comprise the blood-brain barrier, and not being picked up by P-gp. They say this appears to be because it is not recognised as being a "foreign" substance. (C)BBC

Keyword: Glia; Hormones & Behavior
Link ID: 7807 - Posted: 08.27.2005

Christen Brownlee By fusing an embryonic stem cell with an adult skin cell, researchers have created cells that retain valuable embryonic characteristics but carry the adult cell's genes. This new method might eventually lead to stem cell lines that match a patient's DNA while avoiding the destruction of human embryos, a process that some people find morally unacceptable. Scientists envision someday using embryolike cells to grow tissues for transplant or transplanting such cells into a patient, where they would grow to replace damaged or diseased tissues. If these cells carried a patient's genetic material, they might sidestep the risk of a destructive immune reaction. Some scientists also predict that cells with embryonic properties could give researchers a new way to study genetic diseases. Cells that carry the DNA from a patient with a genetic disease could differentiate in a petri dish, permitting scientists to observe how disease characteristics develop. Korean scientists recently created the first lines of embryonic stem cells derived from clones made with people's cells. However, the team used more than 100 human eggs, which are difficult to obtain, and created early human embryos, which they destroyed to harvest stem cells (SN: 5/21/05, p. 323: http://www.sciencenews.org/articles/20050521/fob1.asp). Copyright ©2005 Science Service.

Keyword: Stem Cells
Link ID: 7806 - Posted: 06.24.2010

By Shankar Vedantam The brain areas involved in daydreaming, musing and other stream-of-consciousness thoughts appear to be the same regions targeted by Alzheimer's disease, researchers are reporting today in an unusual study that offers new insights into the roots of the deadly illness. The strong correlation between the two suggests there might be a link between the sort of thinking that people regularly do when not involved in purposeful mental activity and the degenerative disease that is characterized by forgetfulness and dementia, said scientists who conducted the federally funded study. Randy Buckner, a neuroscientist at Washington University in St. Louis, said the implications of the finding are far from clear. It is too early to suggest that daydreaming is dangerous, he said, or that avoiding such musings could affect the risk of Alzheimer's disease. Rather, he and others said, the study adds to the evidence that everyday mental and physical activities play an important role in the course of neurological disease. "It suggests an avenue between brain activity patterns and Alzheimer's disease that we just hadn't been thinking about," said Buckner, who led the study. "It is going to take some time to understand the relative potential of this link." © 2005 The Washington Post Company

Keyword: Alzheimers
Link ID: 7805 - Posted: 06.24.2010

BOSTON--Dana-Farber Cancer Institute researchers say they have uncovered a molecular explanation for the episodic attacks of irrational and demented behavior in porphyria, the disease believed to have afflicted "Mad" King George III, the British ruler blamed for the loss of the American colonies in the Revolutionary War. The mental and physical symptoms of porphyria, a rare genetic blood disease which a number of modern researchers believe plagued King George intermittently throughout his tumultuous reign, can be brought on by fasting and exposure to certain drugs, and is successfully treated by feedings of sugar and high-carbohydrate food. A biological explanation for these nutritional effects has been lacking. The Dana-Farber scientists say in a report featured on the cover of the August 26 issue of Cell that the nutritional component of porphyria involves a key master metabolic molecule, PGC-1 alpha, in cells of the liver. The gene that makes PGC-1 alpha was isolated in 1998 in the laboratory of Bruce Spiegelman, PhD, who is senior author of the new report. Postdoctoral fellow Christopher Handschin, PhD, is lead author. "We've explained how porphyria symptoms can occur in episodic attacks triggered by fasting, and why they can be treated by feeding carbohydrates and glucose," says Spiegelman.

Keyword: Miscellaneous
Link ID: 7804 - Posted: 08.26.2005

NEW YORK, NY, – An increasingly common method of heroin detoxification under general anesthesia is ineffective and unsafe, according to a study by psychiatrists at Columbia University Medical Center and the New York State Psychiatric Institute at Columbia. The study, published in the August 24 Journal of the American Medical Association (JAMA), is the first rigorously controlled trial to monitor all of the critical outcomes associated with the procedure, including comfort, treatment retention, abstinence rates and the ability to receive the full and effective dose of naltrexone, a drug that blocks activation on the receptor sites in the brain where the opioids attach. Heroin addiction is notoriously difficult to overcome. The nervous system of heroin users adapts over time to accommodate to chronic exposure to the opioid, and its sudden absence during detoxification results in excruciating withdrawal symptoms, including nausea, diarrhea, abdominal pain, insomnia and irritability. Despite improvements in recent decades, medically supervised heroin withdrawal remains plagued by patient discomfort and high dropout rates. This has led to the growth of ultra-rapid, anesthesia-assisted opioid withdrawal procedures, which have been publicized as a fast, painless way to withdraw from opioids.

Keyword: Drug Abuse
Link ID: 7803 - Posted: 06.24.2010

A study published in the current issue of Psychological Science investigates the controversy about whether bisexual men exist. In terms of behavior and identity, they clearly exist as there are men who have sex with both men and women. Upon measuring genital, as well as, self-reported sexual arousal to male and female stimuli, researchers found that, in general, bisexual men did not have a strong genital arousal to both male and female sexual stimuli. Instead, they had strong genital arousal to one sex or the other, but not to both. Most of the time, bisexual men had a genital arousal pattern similar to that of gay men, with stronger genital arousal to male stimuli. However, a subset of bisexual men had genital arousal patterns similar to those of heterosexual men. In contrast to genital arousal patterns, self-reported sexual arousal of bisexual men was substantial to both sexes. The researchers interpreted their results as a lack of a bisexual arousal pattern. "Rather they [the bisexual men] seem to be interpreting or reporting their arousal patterns differently than other men do," researchers Gerulf Rieger, Meredith L. Chivers, and J. Michael Bailey state.

Keyword: Sexual Behavior
Link ID: 7802 - Posted: 08.26.2005

NEW BRUNSWICK/PISCATAWAY, N.J. -- Rutgers' Bonnie Firestein likens nerve cells to trees -- some are short and bushy with many branches while others are tall with a few branches coming out of one or two main trunks. Different branching patterns correlate with specific disorders and Firestein's quest is to discover how these dissimilar patterns come about and why. A new paper by Firestein and her colleagues at Rutgers, The State University of New Jersey, examines the role of the protein snapin in nerve branch, or dendrite, patterning and its potential as a drug target in therapies aimed at learning and memory disorders. The article will appear in the journal Molecular Biology of the Cell but appeared online today at MBC in Press (www.molbiolcell.org/in_press.shtml). While disorders like autism may arise from a multiplicity of causes, research at the cellular level, such as that of Firestein and her Rutgers team, is creating an important point of entry for early intervention with therapeutic drugs. Dendrites are the input centers of neurons -- where nerve cells receive information that they pass on to another nerve cell or to the brain. When there is an abnormal decrease in dendrite branches, there are fewer sites to receive information and communication may be impeded. Individuals with disorders such as autism and Rett syndrome display not only fewer branches, but also show two quite different dendrite patterns.

Keyword: Autism; Learning & Memory
Link ID: 7801 - Posted: 08.26.2005

New research performed in rats suggests that orexin, a brain chemical involved in feeding behavior, arousal, and sleep, also plays a role in reward function and drug-seeking behavior. Dr. Glenda Harris and her colleagues at the University of Pennsylvania showed that the activation of orexin-secreting brain cells in the hypothalamus, a brain region that controls many vital functions such as eating, body temperature, fat metabolism, etc. is strongly correlated with food- and drug-seeking behaviors. Past anatomical studies have shown that these cells in the lateral hypothalamus also project to adjacent reward-associated areas of the brain. This study suggests that orexin may be a factor in modulating reward-seeking characteristic of substance abuse. The findings help to better identify neural pathways involved in drug abuse, craving and relapse, which may ultimately help scientists find more effective therapies. This study is published online August 14, 2005 in the journal Nature.

Keyword: Drug Abuse; Obesity
Link ID: 7800 - Posted: 08.26.2005

Roxanne Khamsi The discovery of a group of pitch-sensitive cells in the brain has sent reverberations through the field of music perception. Researchers think that studying these neurons will reveal how our minds grasp songs and speech. Most people can hear that two instruments are playing the same note, even if they sound as different as a trumpet and a piano. Our perception of fundamental sound frequency or 'pitch' remains constant despite differences in an instrument's acoustical traits. This holds true even when the fundamental frequency is actually missing from a complex sound. If several strings are plucked such that they vibrate at their higher harmonics, at 800, 1,000 and 1,200 hertz for example, we will perceive the sound as belonging to the same pitch as the primary harmonic of those strings: 200 hertz. For centuries scholars have puzzled over how the brain does this. In recent years, researchers have looked at the role played by the primary auditory cortex, the brain region known to digest sounds. Human brain scans have indicated that a peripheral bit of this brain region is active when we try to identify pitch. But no one could find cells that responded to specific frequencies, leaving it a mystery how we interpret them. ©2005 Nature Publishing Group

Keyword: Hearing
Link ID: 7799 - Posted: 06.24.2010

Carina Dennis Women have long been known to experience more pain than men. And the idea that sex hormones are to blame has just been bolstered by a study into pain thresholds in a unique study group: people undergoing sex-change operations. Men taking female hormones often start to experience chronic pain, says Anna Maria Aloisi, a physiologist from the University of Siena in Italy. In a study of 54 men taking oestrogen and anti-androgens as treatment to become women, 30% reported developing pains, primarily chronic headaches, during their treatment. "We found that oestrogen in high amounts induced pain in these men," says Aloisi, who presented her work at the 11th World Congress on Pain in Sydney, Australia, this week. In another study of women taking testosterone to become men, says Aloisi, more than half found their aches and pains improved. "They seemed to feel better generally," she adds. The results back up previous research on sex differences in pain. Although no one knows exactly how sex hormones affect pain tolerance, researchers think testosterone dulls pain by muting the excitatory pain pathways in the central nervous system, while oestrogen heightens pain by blocking the inhibitory mechanisms that damp pain sensing. ©2005 Nature Publishing Group

Keyword: Pain & Touch; Sexual Behavior
Link ID: 7798 - Posted: 06.24.2010

IN INTERNET chat rooms, veterans ask if anyone else is having a similar experience. "I had an incident where a small Iraqi boy had his leg blown off. His screams haunt my thoughts. Is what I am experiencing normal?" asks IraqCowboy. "They gave me sleeping pills, but it doesn't stop the nightmares," says Chucky. "The doctor says my husband has PTSD," posts Sam. "Does that count as a combat-related illness?" What is now known as PTSD, or post-traumatic stress disorder, was called shell shock back in the days of the first world war. Sufferers have harrowing flashbacks, and alternate between emotional numbness and outbursts of rage, guilt and depression. Previously well-adjusted soldiers suffer impaired memory and attention, insomnia and anxiety, and are more likely to take drugs and alcohol later in life. That much is well recognised. What is less well known is that PTSD can trigger physical as well as psychological ill health. And as the US agonises over how long its soldiers should stay in Iraq, New Scientist has pieced together evidence showing that veterans will be paying the price of combat for decades to come. Recent and soon-to-be published research reveals that soldiers who fought in theatres as diverse as Vietnam and Lebanon are not only more likely to die from an accident on their return, but are also twice as likely to develop cardiovascular disease, diabetes and even cancer later in life. And these problems are particularly likely to afflict troops who experience the close-quarters fighting taking place in Iraq. © Copyright Reed Business Information Ltd.

Keyword: Stress
Link ID: 7797 - Posted: 06.24.2010

Researchers have discovered how the abnormal repetition of a genetic sequence can have disastrous consequences that lead to the death of neurons that govern balance and motor coordination. The studies bolster the emerging theory that neurodegenerative disorders can be caused by having extra copies of a normal protein, not just a mutated one. People who are afflicted with the rare neurodegenerative disorder spinocerebellar ataxia type 1 (SCA1) suffer damage to cerebellar Purkinje cells caused by a toxic buildup of the protein Ataxin-1. Researchers knew that SCA1, Huntington's disease and other related disorders arise because of a “genetic stutter,” in which a mutation causes a particular gene sequence to repeat itself. These abnormal genetic repeats cause the resulting proteins to contain unusually long repetitive stretches of the amino acid glutamine. The new findings, which are published in the August 26, 2005, issue of the journal Cell, provide a molecular explanation for Ataxin-1's assault on cerebellar Purkinje cells. The findings should help to understand a range of diseases, including Huntington's disease, which are caused by an abnormal number of repetitive gene sequences. The discovery may also offer a new conceptual approach to understanding the pathology of Parkinson's disease and Alzheimer's disease, according to Huda Y. Zoghbi, a Howard Hughes Medical Institute investigator at the Baylor College of Medicine. © 2005 Howard Hughes Medical Institute.

Keyword: Movement Disorders
Link ID: 7796 - Posted: 06.24.2010

Using muscle tissue from tarantulas, an HHMI international research scholar and his colleagues have figured out the detailed structure and arrangement of the miniature molecular motors that control movement. Their work, which takes advantage of a new technique for visualizing tissues in their natural state, provides new insights into the molecular basis of muscle relaxation, and perhaps its activation too. “We have solved the structure of the array of miniature motors that form our muscles and found out how they are switched off,” said Raúl Padrón, a HHMI international research scholar in the Department of Structural Biology at the Venezuelan Institute for Scientific Research (Instituto Venezolano de Investigaciones Científicas or IVIC) in Caracas, Venezuela. The findings are reported in the August 25, 2005, issue of the journal Nature. Padrón and his colleagues focused their studies on striated muscle—the type of muscle that controls skeletal movement and contractions of the heart. Striated muscles are made of long cylindrical cells called muscle fibers. Within the fibers, millions of units known as sarcomeres give rise to movement of skeletal muscles. Sarcomeres are composed mainly of thick filaments of myosin, the most common protein in muscle cells, responsible for their elastic and contractile properties. The thick filaments are arranged in parallel with thin filaments of another muscle protein, actin. When the actin and myosin filaments slide along one another, the muscle contracts or relaxes. © 2005 Howard Hughes Medical Institute.

Keyword: Biomechanics; Muscles
Link ID: 7795 - Posted: 06.24.2010

By Shankar Vedantam The brain areas involved in daydreaming, musing and other stream-of-consciousness thoughts appear to be the same regions targeted by Alzheimer's disease, researchers are reporting today in an unusual study that offers new insights into the roots of the deadly illness. The strong correlation between the two suggests there might be a link between the sort of thinking that people regularly do when not involved in purposeful mental activity and the degenerative disease that is characterized by forgetfulness and dementia, said scientists who conducted the federally funded study. Randy Buckner, a neuroscientist at Washington University in St. Louis, said the implications of the finding are far from clear. It is too early to suggest that daydreaming is dangerous, he said, or that avoiding such musings could affect the risk of Alzheimer's disease. Rather, he and others said, the study adds to the evidence that everyday mental and physical activities play an important role in the course of neurological disease. "It suggests an avenue between brain activity patterns and Alzheimer's disease that we just hadn't been thinking about," said Buckner, who led the study. "It is going to take some time to understand the relative potential of this link." © Copyright 1996-2005 The Washington Post Company

Keyword: Alzheimers
Link ID: 7794 - Posted: 06.24.2010

CHICAGO (Reuters) - A human fetus is unlikely to feel pain before the third trimester, when consciousness begins to form, researchers said on Tuesday in a report that could fuel debate over proposed U.S. abortion legislation. Even if a fetus feels pain, doctors may not be able to anesthetize it without endangering the mother's health, including during an abortion, the researchers wrote in the Journal of the American Medical Association. Legislation under consideration by the U.S. Congress and some U.S. states would require doctors to inform women seeking abortions after the 22nd week of gestation that their fetus feels pain and offer to anesthetize the fetus. Supporters of the legislation say that when a fetus displays a withdrawal reflex or hormonal stress response, that is evidence of fetal pain. But the researchers at the University of California, San Francisco, questioned that view, saying the responses may be automatic and not signs of discomfort. Drawing on findings from thousands of medical-journal articles on the subject of fetal pain and related topics, the report's author, Susan Lee, wrote that "pain is a subjective sensory and emotional experience that requires the presence of consciousness." Copyright © 2005 Reuters Limited.

Keyword: Pain & Touch
Link ID: 7793 - Posted: 06.24.2010

The finding comes from a study of 200 parents (100 men and 100 women). The parents, who were about 38 years old and lived in the U.K., were asked how tall they are. "On average, males overestimated height while females reported their height relatively accurately," write the researchers in the Archives of Disease in Childhood. How far off were the men's estimates? That varied, but 27 percent overestimated their height by an inch or more, compared with 13 percent of the women, the study shows. Parents' height is often used to help predict a child's future height. Based on this study, it might be worth double-checking parents' self-reported height. "We recommend that efforts should be made to measure both parents at the earliest opportunity and record their heights in the child health record," write the researchers. They included W.F. Paterson of the child health department at the Royal Hospital for Sick Children in Glasgow, Scotland. ©MMV, CBS Broadcasting Inc.

Keyword: Sexual Behavior; Evolution
Link ID: 7792 - Posted: 06.24.2010

BUFFALO, N.Y. -- Neuroscientists from the University at Buffalo have described for the first time how rotenone, an environmental toxin linked specifically to Parkinson's disease, selectively destroys the neurons that produce dopamine, the neurotransmitter critical to body movement and muscle control. Microtubules, intracellular highways that transport dopamine to the brain area that controls body movement, are the crucial target, they report. Damage to microtubules prevents dopamine from reaching the brain's movement center, causing a back-up of the neurotransmitter in the transport system, the researchers found. The backed-up dopamine accumulates in the body of the neuron and breaks down, causing a release of toxic free radicals, which destroy the neuron. The study appeared in the Aug. 9 issue of the Journal of Biological Chemistry. "This study shows how an environmental toxin affects the survival of dopamine neurons by targeting microtubules that are critical for the survival of dopamine-producing neurons," said Jian Feng, Ph.D., assistant professor of physiology and biophysics in the UB School of Medicine and Biomedical Sciences and senior author on the study.

Keyword: Parkinsons; Neurotoxins
Link ID: 7791 - Posted: 08.24.2005