Links for Keyword: Neuroimmunology
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Ewen Callaway A study showing how HIV could prevent the brain from making new neurons offers an explanation for why some AIDS patients get dementia — and suggests a possible treatment. Dementia due to HIV is the leading cause of cognitive decline in people under 40 years of age, says Stuart Lipton, a biologist at the Burnham Institute for Medical Research in La Jolla, California, who led the study in Cell Stem Cell1. Researchers aren't sure what causes the condition, which afflicts 10-30% of people with HIV and causes symptoms including forgetfulness and leg weakness. If untreated with antiretroviral drugs, sufferers can turn comatose. Biologists have two theories to explain AIDS-related dementia. It could be that when HIV infects a type of white blood cell called a macrophage, the cell pumps out inflammatory chemicals to battle the infection that also, unfortunately, wipe out neurons. Or HIV could inflict its damage more directly. One previous study showed that a protein in the virus's shell — called gp120 — can stop brain stem cells from dividing2. Such new stem cells are needed to make new neurons. To investigate, Lipton and postdoc Shu-ichi Okamoto studied a strain of mice genetically engineered to make the virus's gp120 protein. Under the microscope, the mouse brains look just like those of humans with AIDS-related dementia, says Lipton. ©2007 Nature Publishing Group
Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 11: Emotions, Aggression, and Stress
Link ID: 10607 - Posted: 06.24.2010
PITTSBURGH—Happiness and other positive emotions play an even more important role in health than previously thought, according to a study published in the journal Psychosomatic Medicine by Carnegie Mellon University Psychology Professor Sheldon Cohen. The paper will be available online at www.psychosomaticmedicine.org/. This recent study confirms the results of a landmark 2004 paper in which Cohen and his colleagues found that people who are happy, lively, calm or exhibit other positive emotions are less likely to become ill when they are exposed to a cold virus than those who report few of these emotions. In that study, Cohen found that when they do come down with a cold, happy people report fewer symptoms than would be expected from objective measures of their illness. In contrast, reporting more negative emotions such as depression, anxiety and anger was not associated with catching colds. That study, however, left open the possibility that the greater resistance to infectious illness among happier people may not have been due to happiness, but rather to other characteristics that are often associated with reporting positive emotions such as optimism, extraversion, feelings of purpose in life and self-esteem. Cohen's recent study controls for those variables, with the same result: The people who report positive emotions are less likely to catch colds and also less likely to report symptoms when they do get sick. This held true regardless of their levels of optimism, extraversion, purpose and self-esteem, and of their age, race, gender, education, body mass or prestudy immunity to the virus.
WASHINGTON — Underscoring the value of good prenatal care, new research suggests that early infection may create a cognitive vulnerability that appears later during stress on the immune system. Researchers at the University of Colorado at Boulder have reported that rats who experienced a one-time infection as newborns didn’t learn as well as adult rats who were not infected as pups, after their immunity was challenged. The research is in February’s Behavioral Neuroscience, published by the American Psychological Association (APA). The findings fit into a growing body of evidence that even a one-time infection can potentially permanently change physiological systems, a phenomenon called “perinatal programming.” Understanding how infection in newborns can disrupt memory in immune-challenged adults may help scientists to understand how exposure to germs or environmental stressors before or just after birth may foster susceptibility to neuropsychiatric and neurodegenerative diseases. For example, prenatal viral infection has been implicated in schizophrenia, autism and cerebral palsy; bacterial infection is a risk factor for Parkinson’s disease. Up to 20 percent of pregnancies have complications involving infections of the uterus and its contents, a number that will rise as more children are born premature. © 2005 American Psychological Association
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 13: Memory, Learning, and Development
Link ID: 6821 - Posted: 06.24.2010
In the midst of a flu epidemic, some good news—researchers think they've solved the age-old medical mystery of why shy, sensitive people are more vulnerable to infectious disease. From the common cold to life-threatening infections, researchers have known for a while that shy people—whom ancient Greek physicians described as having a "melancholic temperament"—are more vulnerable to infectious diseases than their more outgoing counterparts. "We knew that these shy, sensitive introverted people were more vulnerable to infectious diseases," says Steve Cole, assistant professor of hematology-oncology at the David Geffen School of Medicine and a member of the UCLA AIDS Institute. "But we didn't know why that was. What physical biology leaves them more vulnerable to these kinds of diseases?" © ScienCentral, 2000-2003.
The stress a married couple experiences during a 30-minute argument can delay their bodies’ ability to heal a wound by at least a day, according to a new study. And if the couples’ relationship endures routine hostility, the delay can be even longer. There could be important implications for people suffering from chronic wounds, such as skin ulcers. “We knew that chronic stress causes reduced immunity, but to find that an argument of just half an hour has such a profound effect on wound healing is quite shocking,” says Patricia Price at the Wound Healing Research Unit at Cardiff University, Wales, who was not involved in the study. Researchers at Ohio State University College of Medicine in the US inflicted small wounds on 42 otherwise healthy married couples, whose ages ranged from 22 to 77. Each partner was wounded on the forearm with a punch biopsy device, which scrapes off eight patches of the skin's surface, each 8 millimetres in diameter, to leave small open sores. Before a blister could form, another device was used to create a protective bubble over each wound from which the researchers could extract the fluids that normally fill such blisters. © Copyright Reed Business Information Ltd.
Mice that are briefly stressed out before receiving a vaccine develop a better immune response than mice under no psychological stress, a new study reveals. This advantageous immunity persists for at least nine months - a good chunk of a mouse lifespan - and is likely to arise because an acutely stressed immune system develops better memories for foreign invaders, the study’s authors suggest. “Stress can influence different features of the immune response in different ways, sometimes improving and sometimes suppressing” this response, says Monika Fleshner, of the University of Colorado at Boulder, US. While chronic stress suppresses “nearly every feature of the immune system,” acute stress can enhance some features, she says. Firdaus Dhabhar and Kavitha Viswanathan at Ohio State University, US, injected mice with a small amount of protein called keyhole limpet hemocyanin (KLH), which triggers the body’s immune response in a way similar to many proteins, according to Dhabhar. Half of the mice were put in small, unfamiliar wire cages for two and a half hours immediately before receiving their immunisations, while the other half stayed in their regular cages. Nine months later, the researchers injected the animals with KLH at a different skin site. Mice that had been confined before being immunised developed much more skin inflammation than did the non-stressed mice - a sign that their bodies’ immune systems responded more intensely to the new injections. The researchers show that many more immune cells rushed to the injection sites in mice that had been stressed. © Copyright Reed Business Information Ltd
John Pickrell People with many younger siblings are more likely to develop brain tumours, according to a new study. Those with four or more siblings have twice the risk of brain cancer compared to only-children, the study found. The finding suggests that an infectious agent, such as a virus, may be involved in some brain cancers, say the researchers, who compared over 13,000 incidences of the disease. The study also found there was a two- to fourfold increase in brain tumour rates among children younger than 15 who had three or more younger siblings compared to children of the same age who had no siblings. But there was no association between the number of older siblings and brain tumours. "We know very little about why people develop brain tumours," says epidemiologist Andrea Altieri, who led the study at the German Cancer Research Centre in Heidelberg. The only previously established risk factors for brain tumours are large doses of radiation, a family history of brain cancer and rare genetic disorders, he says, but these together only explain about 5% of cases. Other studies have shown a link between the number of siblings and cancers such as lymphomas and leukaemia. Sibling number is thought to be a so-called "indirect marker" of infection in childhood, says Altieri. “The number of siblings a person has indicates the level of exposure they had to infection at an early age, since children come in close contact with each other and thereby share exposures to many infectious agents.” © Copyright Reed Business Information Ltd.
Low levels of social connectedness can adversely affect the body - lowering immune response and affecting heart health - highlight two new studies. One study demonstrates that first-year college students who mixed with fewer people or felt lonely had a lower immune response to influenza vaccination than their more gregarious or socially contented classmates. A second study suggests that men who are socially isolated have elevated levels of a blood marker for inflammation, which has a role in atherosclerosis. It was known that isolation has detrimental effects on heart health, but the study gives clues as to how this is mediated, says Sarah Pressman, a health psychologist a Carnegie Mellon University in Pittsburgh, US. Pressman and colleagues found small social networks and loneliness lowered the antibody response of students to the flu jab. But surprisingly, the effects were independent of one another. “Loneliness is the perception of being alone,” she explains, whereas social networks can be counted objectively as the number of people with whom a person has contact. “You can have very few friends but still not feel lonely. Alternatively, you can have many friends yet feel lonely,” says Pressman. © Copyright Reed Business Information Ltd.
By Gisela Telis Social bees have surprisingly strong body armor against microbes, researchers have found. And the more gregarious the bees--the larger their colonies and the more closely related--the better they are at beating disease. The discovery is the first clear link between the evolution of immune systems and social behavior, and it dangles a new hope for bioprospectors on the trail of the next generation of antibiotics. Insects, like humans, face greater risks of catching and spreading infectious diseases when they're crowded together. Scientists have long suspected that bees and other bugs combat the added risk that being social incurs by evolving stronger disease defenses, such as secreting antimicrobial agents to cover their bodies. The theory is that bigger colonies with more crowded conditions would require insects to evolve better immune defenses, which in turn enable the insects to evolve still-bigger colonies. To test the idea, biologists Adam Stow, Andrew Beattie, and their colleagues at Macquarie University in New South Wales and the South Australian Museum in Adelaide collected bees from across the social spectrum: blue-banded bees and teddy bear bees, which are solitary and live in their own nests without partners or workers; semisocial reed bees that partner with their sisters and their offspring in small colonies; and Australian native honey bees, which form large colonies of closely related individuals with sophisticated divisions of labor. The scientists then washed the protective coatings from the bees' bodies and applied the resulting solution to the notorious Staphylococcus aureus (staph) bacterium. © 2007 American Association for the Advancement of Science.
Bruce Bower People with generally positive outlooks show greater resistance to developing colds than do individuals who rarely revel in upbeat feelings, a new investigation finds. Frequently basking in positive emotions defends against colds regardless of how often one experiences negative emotions, say psychologist Sheldon Cohen of Carnegie Mellon University in Pittsburgh and his colleagues. They suspect that positive emotions stimulate symptom-fighting substances. "We need to take more seriously the possibility that a positive emotional style is a major player in disease risk," Cohen says. In a study published in 2003, his group exposed 334 healthy adults to one of two rhinoviruses via nasal drops. Those who displayed generally positive outlooks, including feelings of liveliness, cheerfulness, and being at ease, were least likely to develop cold symptoms. Unlike the negatively inclined participants, they reported fewer cold symptoms than were detected in medical exams. The new study, which appears in the November/December Psychosomatic Medicine, replicates those results and rules out the possibility that psychological traits related to a positive emotional style, rather than the emotions themselves, guard against cold symptoms. Those traits include high self-esteem, extroversion, optimism, and a feeling of mastery over one's life. ©2006 Science Service.
By Jocelyn Kaiser Nobody likes coming down with a fever, but feeling hot may do a body good. Researchers report online 5 November in Nature Immunology that a fever in mice revs up the immune response by helping white blood cells enter lymph nodes, where they join the battle against microbial invaders. All mammals can develop fever when they're sick enough, and even cold-blooded animals with infections, such as fish and lizards, will seek warmth to raise their body temperatures. This suggests that fever somehow helps the body conquer the bugs. Immunologist Sharon Evans of Roswell Park Cancer Institute in Buffalo, New York, and coworkers are studying how fever affects the movement of white blood cells, or lymphocytes, from the blood into lymphoid tissue, where they learn to recognize and fight pathogens. Lymphocytes constantly circulate through blood vessels within lymph nodes and other lymphoid organs, but only some actually enter lymphoid tissue by crossing the walls of the vessels, known as high endothelial venules (HEVs). Fever increases blood flow, which means more lymphocytes flow through lymphoid tissues. Evans' team had previously shown that fever also assists the passage of lymphocytes into lymphoid tissue, but they hadn't figured out what was happening on a molecular level. © 2006 American Association for the Advancement of Science.
Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 11: Emotions, Aggression, and Stress
Link ID: 9594 - Posted: 06.24.2010
Helen Pearson A messy birth could be good for the baby's digestion. So say researchers in Germany, who have found evidence that baby mice squeezing through the birth canal swallow bacterial molecules that help their gut grow healthily. The finding suggests that kids born by caesarean might miss out. Swarms of friendly bacteria normally live in our guts, and cells lining the intestinal tubes do not attack them. Mathias Hornef at the University Clinic of Freiburg, Germany, and his colleagues, have found that, in mice at least, these intestinal cells 'learn' not to harm the bugs sometime around birth. The team extracted intestinal cells from mice embryos before birth and exposed them to a component of bacteria. The embryonic cells reacted and produced inflammatory molecules. But the same gut cells from one-day-old newborn mice or adult mice did not. Somehow, the cells in the more developed mice had learned to ignore the bacterial trigger. The researchers think that bacterial scraps naturally slopping around in the birth canal and mother's faeces are swallowed by the baby mice as they make their entry into the world. These molecules pass down into the gut, where they stimulate the gut cells; a single exposure is enough to teach the cells to tolerate friendly bugs in the future. ©2006 Nature Publishing Group
Praying for someone might give you hope, but it won't help them recover from heart surgery. It may even harm them. That's the surprising result from a multi-year clinical trial on the therapeutic effects of prayer. Herbert Benson and Jeffery Dusek of the Mind/Body Medical Institute at Beth Israel Deaconess Medical Center in Chestnut Hill, Massachusetts, and their colleagues followed the fates of 1802 patients undergoing coronary bypass operations. Several Christian prayer groups prayed for one set of patients, while another did not receive any prayers. Although all these patients knew they were in the trial, neither they nor their doctors knew which of the groups they were in. The prayers made no detectable difference. In the first month after surgery, 52 per cent of prayed-for patients and 51 per cent of non-prayed-for patients suffered one or more complications, the researchers found (American Heart Journal, vol 151, p 934). A third group of patients received the same prayers as the first group, but were told they were being prayed for. Of these, 59 per cent suffered complications - significantly more than the patients left unsure of whether they were receiving prayers. © Copyright Reed Business Information Ltd
By JR Minkel In 2002 a clinical trial of an experimental Alzheimer's vaccine was halted when a few patients began experiencing brain inflammation, a result of the immune system mounting an attack against the body. Now some researchers claim that inducing a mild autoimmune reaction could actually protect the central nervous system from a spectrum of neurodegenerative conditions, from glaucoma and spinal cord injury to Parkinson's and Alzheimer's disease. "This is a hot-button issue right now," says Howard Gendelman of the University of Nebraska Medical Center in Omaha. It all started with glaucoma. Once thought to result primarily from high pressure in the eyeball constricting the optic nerve, the disease has lately come to be seen as a form of neurodegeneration, propagating from the injured optic nerve to healthy cells in the brain. Before monkey studies had demonstrated as much, neuroimmunologist Michal Schwartz of the Weizmann Institute in Rehovot, Israel, observed in the late 1990s that crushing a small portion of a rat optic nerve creates a large zone of sickened cells. She and her team also found that T cells, the immune system's attackers, gathered at these wounds. © 1996-2006 Scientific American, Inc.
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 5: The Sensorimotor System
Link ID: 8368 - Posted: 06.24.2010
By David Kohn Blanche Cardarelli is a very friendly person. Almost every day, she spends at least a few hours hanging out with one group of people or another. She belongs to seven social clubs and, by her count, has dozens of friends. "I like people. I like being around people," says Cardarelli, a former homemaker who lives in the Middleborough section of Essex. "You can either sit home and watch TV or you can go out." Cardarelli, a widow who is in her early 70s ("I don't give my age away because that keeps my boyfriends around," she jokes), has a good chance of living for many more years, at least according to a study of almost 1,500 people aged 70 and older. The research, which appears in the July issue of the Journal of Epidemiology and Community Health, found that people who had more friends and who spent more time with them tended to live longer. Intriguingly, the researchers found that spending time with family did not seem to lengthen life. The study followed subjects for 10 years. The most interactive group, people who had five or more close friends and talked with them regularly, were 22 percent less likely to die than those who were least connected - no close friends and few social contacts of any kind. Copyright © 2005, The Baltimore Sun
Roxanne Khamsi People itching for a solution to seasonal allergies could get help from self-hypnosis, a team of Swiss researchers suggests. The study finds that simply focusing one's thoughts on allergen-free environments can reduce symptoms of hay fever by one-third. Although the arrival of spring brings better weather, it also triggers the release of plant pollens that cause allergies. Hay fever affects about 10-15% of adults in industrialized nations. To treat this, people turn to medications such as antihistamines, decongestants and sometimes steroids. But these can cause side-effects such as drowsiness, a dry mouth and raised blood pressure. Allergy sufferers have sought alternatives approaches, including psychotherapy-related methods, to ease their itchy eyes and runny noses. Wolf Langewitz of the University Hospital Basel, Switzerland, and his colleagues sought to find out how well self-hypnosis works. The team recruited 79 patients with moderate to severe allergic reactions to grass or tree pollen, who then received training on self-hypnosis. To achieve successful results using self-hypnosis, says Langewitz, one must first enter a trance-like state and then focus the mind on a particular theme. The whole process, he adds, can take as little as five minutes. ©2005 Nature Publishing Group
Friends, not family, are the key to a longer life, a new study suggests. While previous research has found that strong social networks help older people live longer, the work had not distinguished between contact with friends or relatives. The new study followed almost 1500 Australians, initially aged over 70. Those who at the start reported regular close personal or phone contact with five or more friends were 22% less likely to die in the next decade than those who had reported fewer, more-distant friends. But the presence or absence of close ties with children or other relatives had no impact on survival. The reasons are not entirely clear. Friends and confidantes might help with coping in times of stress and difficulty, the team suggests. They might also encourage healthy behaviours, such as seeking help for new medical symptoms. Journal reference: Journal of Epidemiological and Community Health (vol 59, p 538) © Copyright Reed Business Information Ltd.
Rest assured, the cells that guard your brain are no slackers. New movies of brain cells called microglia reveal that these sentries constantly extend and retract tiny arms to probe the fluid spaces between brain cells for signs of injury or infection. The findings present a radically new view of how these cells protect the brain. Microglia are the immune system's foot soldiers in the brain. They spring into action when damage occurs, creating a protective barrier around the injury and cleaning up dead cells and other debris. What the microglia do between crises has been unclear, largely because getting the cells under a microscope has required excising a chunk of brain tissue--thereby causing damage that sends the cells into emergency response mode. The new study gets around that obstacle by using genetically engineered mice whose microglia produce a fluorescent green protein. The research team, led by Axel Nimmerjahn at the Max Planck Institute for Medical Research in Heidelberg, Germany, created a window on the brain of 12 such mice by shaving away a small patch of skull until only a transparent sliver of bone remained. Using a noninvasive technique called two-photon microscopy, the team snapped pictures of glowing microglia near the surface of the brain for several hours and compiled the images into time-lapse movies. Copyright © 2005 by the American Association for the Advancement of Science.
By Rob Stein, Washington Post Staff Writer According to the Bible, "a merry heart doeth good like a medicine." Now, modern science may be validating that Old Testament proverb -- a good laugh may actually help fend off heart attacks and strokes. "We believe laughing is good for your health," said Michael Miller of the University of Maryland School of Medicine in Baltimore, who led the research. "And we think we have evidence to show why that's the case." A growing body of other evidence has suggested that negative emotions, particularly depression and stress, can be harmful, making people more prone to illness, more likely to experience suffering from their ailments and less likely to recover as quickly, or at all. One recent study even found sudden emotional shock can trigger life-threatening heart symptoms that many doctors mistake for a classic heart attack. Miller himself, along with his colleagues, had done a study that found people who have a negative reaction to social situations tend to be more prone to heart disease. But far less has been done to examine whether positive emotions can reduce the risk and complications of illness. © 2005 The Washington Post Company
A BIG brain is a sign of a healthy immune system, at least as far as male birds are concerned. Anders Møller at Pierre and Marie Curie University in Paris, France, and colleagues examined data from 127 bird species. They found that in species with larger brains for their body size, such as yellowhammers and barn swallows, the males also tended to have a larger spleen and bursa of Fabricius - two organs central to the immune system. The pattern did not hold for organs like the heart and liver not involved the immune system, or for females (Journal of Evolutionary Biology, DOI: 10.1111/j.1420-9101.2004.00805.x). Møller says that females choosing brainy males, perhaps by favouring a large song repertoire, may also be selecting for males with better immune systems. Previous research has shown that infections impair a bird's cognitive abilities, so a male displaying his braininess may also be showing off good genes for seeing off parasites. What's more the pattern may exist in other animals. "I can't see any reason why it should be restricted to birds," Møller says. © Copyright Reed Business Information Ltd.
Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 11: Emotions, Aggression, and Stress
Link ID: 6668 - Posted: 06.24.2010