Education: States’ standardized tests have a negative impact on parents’ civic engagement

New research from a political scientist at the University of Massachusetts Amherst has found that parents of public school students in states with more extensive and stringent student assessment systems express lower trust in government, less confidence in government efficacy, and more negative views of their children’s schools, thereby threatening civic engagement and the potential for future education reform.In a study published by the journal Political Behavior, associate professor Jesse Rhodes merged data from an original survey of public school parents with quantitative measures of the scope and alignment of state standards, testing, and accountability policies, to determine whether and how education reforms influence the parents’ political attitudes and behaviors.He found that highly developed assessment policies alienate parents from government and discourage parental involvement in education, an effect he terms “demobilization.” Parental trust in government was 11 percent lower in states with the most extensive assessment policies, and parental assessments of government effectiveness were 15 percent lower, compared to states with less developed testing polices.Over the past decade, federal education policies such as No Child Left Behind and Race to the Top have led states to develop and adopt education reforms, including content standards specifying what children should know and be able to do, assessments measuring student progress toward those standards and systems of policies holding schools accountable for performance. As years have passed these policies have extended to a greater number of subjects and a wider range of education levels, but there is considerable state-by-state variation in the policies.While previous studies have examined how these policies affect student achievement, Rhodes’ research is the first to assess how they affect the citizenship practices of public school parents — a key education stakeholder.”Today, with trust in government near an all-time low, government’s authority to accomplish collective objectives is arguably at low ebb,” Rhodes writes in the study. “My findings indicate that standards-based reform policies may be further threatening the foundation of public support that government needs to function effectively.”In addition to their negative views of government, Rhodes also found that parents in states with more developed assessment systems were less likely to become engaged in some parental involvement behaviors, especially contacting teachers and participating in school fundraisers. The likelihood that parents would contact their children’s teachers was 17 percent lower in states with the most stringent testing policies, and the chance they would participate in school fundraisers was 28 percent lower. Parents residing in states with more developed assessment systems were more likely to attend their local school board meetings, but Rhodes argues that this involvement is stimulated by anger and dissatisfaction with the perceived negative consequences of state assessments.He argues that these policies tend to depress civic engagement among parents because they provide few opportunities for parental input and can introduce undesirable changes into schools.”My findings suggest that a major reassessment of standards, testing, and accountability policies is necessary,” Rhodes concludes. “At a minimum, standards-based reforms must be redesigned so that they engage parents more directly in the process of policy design and administration and allay parental concerns about counter-productive consequences. However, given the seriousness of the problems identified here, it is possible that an even more searching reevaluation of the standards-based agenda is necessary. Today, the question for policymakers and citizens is how to design education policies that advance the objective of high achievement for all students while strengthening the practice of citizenship for all adults.”Story Source:The above story is based on materials provided by University of Massachusetts Amherst. Note: Materials may be edited for content and length.

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‘RoboClam’ replicates a clam’s ability to burrow while using little energy

The Atlantic razor clam uses very little energy to burrow into undersea soil at high speed. Now a detailed insight into how the animal digs has led to the development of a robotic clam that can perform the same trick.The device, known as “RoboClam,” could be used to dig itself into the ground to bury anchors or destroy underwater mines, according to its developer, Amos Winter, the Robert N. Noyce Career Development Assistant Professor of Mechanical Engineering at MIT.Despite its rigid shell, the Atlantic razor clam (Ensis directus) can move through soil at a speed of 1 centimeter per second. What’s more, the animal is able to dig up to 0.5 kilometers using only the amount of energy contained in a AA battery. “The clam’s trick is to move its shells in such a way as to liquefy the soil around its body, reducing the drag acting upon it,” Winter says. “This means it requires much less force to pull its shell into the soil than it would when moving through static soil.”To develop a robot that can perform the same trick, Winter and his co-developer, Anette Hosoi, professor of mechanical engineering and applied mathematics at MIT, needed to understand how the clam’s movement causes the soil to liquefy, or turn into quicksand, around its shell. Now, in a paper to be published in the journal Bioinspiration and Biomimetics, the researchers reveal for the first time the mechanics behind this process, and describe how their robot is able to mimic this action.Mechanics of quicksandWhen the razor clam begins to dig, it first retracts its shell, releasing the stress between its body and the soil around it. This causes the soil to begin collapsing, creating a localized landslide around the animal. As the clam continues to contract, reducing its own volume, it sucks water into this region of failing soil. The water and sand particles mix, creating a fluidized substrate — quicksand.But the timing is crucial. …

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Pre-term birth leads to increased risk of asthma, wheezing disorders

Researchers at Brigham and Women’s Hospital (BWH) in Boston, Massachusetts, in collaboration with investigators at the Maastricht University Medical Centre and Maastricht University School of Public Health in the Netherlands and The University of Edinburgh in the United Kingdom, have published findings strongly suggesting that preterm birth (prior to 37 weeks gestation) increases the risk of asthma and wheezing disorders during childhood and that the risk of developing these conditions increases as the degree of prematurity increases.The findings are based on a systematic review and meta-analysis of 30 studies that investigated the association between preterm birth and asthma/wheezing disorders among 1.5 million children. These studies were conducted between 1995 and the present, a time span chosen to allow for recent changes in the management of prematurity.Across the studies, 13.7 percent of preterm babies developed asthma/wheezing disorders compared with 8.3 percent of babies born at term, representing a 70 percent increased risk. Children born very early (before 32 weeks gestation) had approximately three times the risk of developing asthma/wheezing disorders compared with babies born at term.”Worldwide, more than 11 percent of babies are born preterm,” said Aziz Sheikh, MD, corresponding author and Harkness Fellow in Health Care Policy and Practice in the Division of General Internal Medicine and Primary Care at Brigham and Women’s Hospital. “As asthma is a chronic condition, our findings underscore the need to improve our understanding of the mechanisms underlying the association between preterm birth and asthma/wheezing disorders in order to develop preventive and therapeutic interventions.”Story Source:The above story is based on materials provided by Brigham and Women’s Hospital. Note: Materials may be edited for content and length.

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Cochlear implant with no exterior hardware can be wirelessly recharged

Cochlear implants — medical devices that electrically stimulate the auditory nerve — have granted at least limited hearing to hundreds of thousands of people worldwide who otherwise would be totally deaf. Existing versions of the device, however, require that a disk-shaped transmitter about an inch in diameter be affixed to the skull, with a wire snaking down to a joint microphone and power source that looks like an oversized hearing aid around the patient’s ear.Researchers at MIT’s Microsystems Technology Laboratory (MTL), together with physicians from Harvard Medical School and the Massachusetts Eye and Ear Infirmary (MEEI), have developed a new, low-power signal-processing chip that could lead to a cochlear implant that requires no external hardware. The implant would be wirelessly recharged and would run for about eight hours on each charge.The researchers describe their chip in a paper they’re presenting this week at the International Solid-State Circuits Conference. The paper’s lead author — Marcus Yip, who completed his PhD at MIT last fall — and his colleagues Rui Jin and Nathan Ickes, both in MIT’s Department of Electrical Engineering and Computer Science, will also exhibit a prototype charger that plugs into an ordinary cell phone and can recharge the signal-processing chip in roughly two minutes.”The idea with this design is that you could use a phone, with an adaptor, to charge the cochlear implant, so you don’t have to be plugged in,” says Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor of Electrical Engineering and corresponding author on the new paper. “Or you could imagine a smart pillow, so you charge overnight, and the next day, it just functions.”Adaptive reuseExisting cochlear implants use an external microphone to gather sound, but the new implant would instead use the natural microphone of the middle ear, which is almost always intact in cochlear-implant patients.The researchers’ design exploits the mechanism of a different type of medical device, known as a middle-ear implant. Delicate bones in the middle ear, known as ossicles, convey the vibrations of the eardrum to the cochlea, the small, spiral chamber in the inner ear that converts acoustic signals to electrical. In patients with middle-ear implants, the cochlea is functional, but one of the ossicles — the stapes — doesn’t vibrate with enough force to stimulate the auditory nerve. A middle-ear implant consists of a tiny sensor that detects the ossicles’ vibrations and an actuator that helps drive the stapes accordingly.The new device would use the same type of sensor, but the signal it generates would travel to a microchip implanted in the ear, which would convert it to an electrical signal and pass it on to an electrode in the cochlea. …

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Opening ‘the X-files’ helped researchers to understand why women and men differ in height

Given its unique nature, the X chromosome has often been neglected when performing large-scale genetic studies. Because women have two copies of this chromosome and men only one, identifying genetic associations with X chromosomal genes can be particularly valuable in helping us to understand why some characteristics differ between sexes. Researchers from the University of Helsinki, Finland, have now identified novel X-chromosomal genetic variants that influence human height.The researchers analyzed thoroughly the commonly occurring genetic variation in chromosome X, one of the two sex-determining chromosomes, in almost 25,000 Northern European individuals with diverse health-related information available. The aim of the study was to find genetic factors that could explain individual differences in several traits, including BMI, height, blood pressure and lipid levels. In addition, the researchers also investigated whether the X chromosome would contribute to some of the well-known differences between men and women in certain traits, such as height. Hundreds of genetic variants having an effect on these traits have already been identified, but, given its unique nature, the X chromosome has been neglected in most of these previous studies.The results were published in PLOS Genetics journal, February 6th.”Studying the X chromosome has some particular challenges. The fact that women have two copies of this chromosome and men only one has to be taken into account in the analysis. We nevertheless wanted to take up the challenge since we had a strong belief that opening ‘the X files’ for research would reveal new, interesting biological insights,” says Dr. Taru Tukiainen who is currently working at the Massachusetts General Hospital in Boston.The study showed that a genetic variant close to ITM2A, a gene that has a role in cartilage development, is frequent among the people being shorter than average. The identified variant, which is present in more than a third of Europeans, was also shown to increase the expression of ITM2A, suggesting that the more the gene is expressed the shorter the person will be. …

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Americans living longer, more healthy lives

Sep. 12, 2013 — Thanks to medical advances, better treatments and new drugs not available a generation ago, the average American born today can expect to live 3.8 years longer than a person born two decades ago. Despite all these new technologies, however, is our increased life expectancy actually adding active and healthy years to our lives? That question has remained largely unanswered — until now. In a first-of-its-kind study, researchers at the University of Massachusetts Medical School (UMMS) have found that the average 25-year-old American today can look forward to 2.4 more years of a healthy life than 20 years ago while a 65-year-old today has gained 1.7 years.Synthesizing data from multiple government-sponsored health surveys conducted over the last 21 years, Allison Rosen, MD, associate professor of Quantitative Health Sciences at UMMS, Susan Stewart, researcher at the National Bureau of Economic Research, and David Cutler, professor of economics at Harvard University, were able, for the first time, to measure how the quality-adjusted life expectancy (QALE) of all Americans has changed over time. The study’s findings are described in a paper published today in the American Journal of Public Health.”QALE tells us more than how long a person can expect to live,” said Dr. Rosen, senior author on the study. “It tells us what the relative quality of those added years are in terms of physical, emotional and mental well-being. Though many studies have measured this in different ways, this is really the first time we’ve been able to capture this type of information across the whole U.S. population over an extended period.”The data shows that Americans are living longer, reporting fewer symptoms of disease, have more energy and show fewer impairment in everyday tasks such as walking than a generation ago. …

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400-year study finds Northeast forests resilient, changing

Sep. 5, 2013 — A joint Harvard-Smithsonian study released today in the journal PLOS ONE reveals how much — and how little — Northeastern forests have changed after centuries of intensive land use.A hike through today’s woods will reveal the same types of trees that a colonial settler would have encountered 400 years ago. But the similarities end there. Jonathan Thompson, research associate at the Smithsonian Conservation Biology Institute and lead author of the new study, explains, “If you only looked at a tree species list, you’d have the impression that Northeast forests haven’t changed. But once you start mapping the trees, and counting them up, a different picture emerges.” Thompson adds, “In some ways the forest is completely transformed.”To draw these conclusions, Thompson and his colleagues compared colonial-era tree records to modern US Forest Service data across a 9-state area stretching from Pennsylvania to Maine.Their results show stark contrasts between pre-colonial forests and today. Maples have exploded across the Northeast, their numbers increasing by more than 20 percent in most towns. Other tree types have declined sharply. Beeches, oaks, and chestnuts show the most pronounced loss — big trouble, Thompson notes, for wildlife that depend on tree nuts for winter survival.Pine numbers have shifted more than any other tree type, increasing in some places, decreasing elsewhere. Thompson pins this variability to ecology and economy: “Pine is valuable for timber, but quick to return after cutting. It has a social and environmental dynamism to it.”The nine states in the study share a similar — and notable — forest history: during the 18th and 19th centuries, more than half the forestland was cleared for agriculture and cut for timber. …

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NASA’s Chandra Observatory catches giant black hole rejecting material

Aug. 29, 2013 — Astronomers using NASA’s Chandra X-ray Observatory have taken a major step in explaining why material around the giant black hole at the center of the Milky Way Galaxy is extraordinarily faint in X-rays. This discovery holds important implications for understanding black holes.New Chandra images of Sagittarius A* (Sgr A*), which is located about 26,000 light-years from Earth, indicate that less than 1 percent of the gas initially within Sgr A*’s gravitational grasp ever reaches the point of no return, also called the event horizon. Instead, much of the gas is ejected before it gets near the event horizon and has a chance to brighten, leading to feeble X-ray emissions.These new findings are the result of one of the longest observation campaigns ever performed with Chandra. The spacecraft collected five weeks’ worth of data on Sgr A* in 2012. The researchers used this observation period to capture unusually detailed and sensitive X-ray images and energy signatures of super-heated gas swirling around Sgr A*, whose mass is about 4 million times that of the sun.”We think most large galaxies have a supermassive black hole at their center, but they are too far away for us to study how matter flows near it,” said Q. Daniel Wang of the University of Massachusetts in Amherst, who led of a study published Thursday in the journal Science. “Sgr A* is one of very few black holes close enough for us to actually witness this process.”The researchers found that the Chandra data from Sgr A* did not support theoretical models in which the X-rays are emitted from a concentration of smaller stars around the black hole. Instead, the X-ray data show the gas near the black hole likely originates from winds produced by a disk-shaped distribution of young massive stars.”This new Chandra image is one of the coolest I’ve ever seen,” said co-author Sera Markoff of the University of Amsterdam in the Netherlands. “We’re watching Sgr A* capture hot gas ejected by nearby stars, and funnel it in towards its event horizon.”To plunge over the event horizon, material captured by a black hole must lose heat and momentum. …

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Social giving makes us happier

Aug. 20, 2013 — People usually feel good when they make a charitable donation, but they feel even better if they make the donation directly to someone they know or in a way that builds social connection. Research to be published in the International Journal of Happiness and Development investigates for the first time how social connection helps turn generous behavior into positive feelings on the part of the donor.Share This:Lara Aknin of Simon Fraser University, in Burnaby, British Columbia, Canada, and colleagues at the University of British Columbia, Vancouver and Harvard Business School, Massachusetts, USA, wanted to examine when the emotional benefits of giving to charity become manifest. They carried out three studies of charitable donations, or more precisely pro-social spending, and found that spending money on others or giving money to charity leads to the greatest happiness boost when giving fosters social connection. The overarching conclusion is that donors feel happiest if they give to a charity via a friend, relative or social connection rather than simply making an anonymous donation to a worthy cause.The research has implications for not-for-profit organizations hoping to maximize donations, suggesting that recruiting advocates and helping them build on their social connections could have benefits for the donors too. Extending these findings, it is possible that if donors have a greater sense of happiness when giving involves making a social connection one might imagine that the positive emotions might even lead to more frequent and perhaps bigger donations. Extrapolating further from the research happy donors might themselves be more likely to become advocates for a given cause or benefit it through their spontaneous word-of-mouth marketing.” The findings also complement earlier research that has demonstrated a positive effect on happiness of social interaction and taking part in voluntary work.”While additional factors other than social connection likely influence the happiness gained from pro-social spending our findings suggest that putting the social in pro-social is one way to transform good deeds into good feelings,” the team concludes.Share this story on Facebook, Twitter, and Google:Other social bookmarking and sharing tools:|Story Source: The above story is based on materials provided by Inderscience Publishers, via EurekAlert!, a service of AAAS. Note: Materials may be edited for content and length. For further information, please contact the source cited above. Need to cite this story in your essay, paper, or report? …

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New MR analysis technique reveals brain tumor response to anti-angiogenesis therapy

Aug. 18, 2013 — A new way of analyzing data acquired in MR imaging appears to be able to identify whether or not tumors are responding to anti-angiogenesis therapy, information that can help physicians determine the most appropriate treatments and discontinue ones that are ineffective. In their report receiving online publication in Nature Medicine, investigators from the Martinos Center for Biomedical Imaging at Massachusetts General Hospital (MGH), describe how their technique, called vessel architectural imaging (VAI), was able to identify changes in brain tumor blood vessels within days of the initiation of anti-angiogenesis therapy.”Until now the only ways of obtaining similar data on the blood vessels in patients’ tumors were either taking a biopsy, which is a surgical procedure that can harm the patients and often cannot be repeated, or PET scanning, which provides limited information and exposes patients to a dose of radiation,” says Kyrre Emblem, PhD, of the Martinos Center, lead and corresponding author of the report. “VAI can acquire all of this information in a single MR exam that takes less than two minutes and can be safely repeated many times.”Previous studies in animals and in human patients have shown that the ability of anti-angiogenesis drugs to improve survival in cancer therapy stems from their ability to “normalize” the abnormal, leaky blood vessels that usually develop in a tumor, improving the perfusion of blood throughout a tumor and the effectiveness of chemotherapy and radiation. In the deadly brain tumor glioblastoma, MGH investigators found that anti-angiogenesis treatment alone significantly extends the survival of some patients by reducing edema, the swelling of brain tissue. In the current report, the MGH team uses VAI to investigate how these drugs produce their effects and which patients benefit.Advanced MR techniques developed in recent years can determine factors like the size, radius and capacity of blood vessels. VAI combines information from two types of advanced MR images and analyzes them in a way that distinguishes among small arteries, veins and capillaries; determines the radius of these vessels and shows how much oxygen is being delivered to tissues. The MGH team used VAI to analyze MR data acquired in a phase 2 clinical trial — led by Tracy Batchelor, MD, director of Pappas Center for Neuro-Oncology at MGH and a co-author of the current paper — of the anti-angiogenesis drug cediranib in patients with recurrent glioblastoma. The images had been taken before treatment started and then 1, 28, 56, and 112 days after it was initiated.In some patients, VAI identified changes reflecting vascular normalization within the tumors — particularly changes in the shape of blood vessels — after 28 days of cediranib therapy and sometimes as early as the next day. Of the 30 patients whose data was analyzed, VAI indicated that 10 were true responders to cediranib, whereas 12 who had a worsening of disease were characterized as non-responders. …

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Stressed bacteria stop growing: Mechanism discovered

Aug. 15, 2013 — Whether a man, a mouse or a microbe, stress is bad for you. Experiments in bacteria by molecular biologists in Peter Chien’s lab at the University of Massachusetts Amherst, with others at MIT, have uncovered the mechanism that translates stress, such as exposure to extreme temperature, into blocked cell growth.It turns out that stressful conditions cause some proteins to be literally bent out of shape, or misfolded, and they stop working, says Chien. “You might think of this as microbial temper tantrums. Bacteria deal with stress by destroying proteins. Specifically, we’ve shown that certain kinds of bacteria respond to high temperatures by destroying proteins needed for DNA replication. Therefore, they stop growing. The signal for this destruction turned out to be the buildup of proteins that were misfolded because of the stress.”Under favorable conditions, cells strive to grow, which means initiating DNA replication. But in stressful conditions, cells must prevent the initiation of replication and instead shift their priorities to protective functions.As Chien explains, all cells including bacteria contain a huge variety of proteins, molecules that help cells do all the chemical reactions needed for life. Shape determines what kind of functions each protein can perform. …

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Brain scans may help diagnose dyslexia

Aug. 13, 2013 — bout 10 percent of the U.S. population suffers from dyslexia, a condition that makes learning to read difficult. Dyslexia is usually diagnosed around second grade, but the results of a new study from MIT could help identify those children before they even begin reading, so they can be given extra help earlier.The study, done with researchers at Boston Children’s Hospital, found a correlation between poor pre-reading skills in kindergartners and the size of a brain structure that connects two language-processing areas.Previous studies have shown that in adults with poor reading skills, this structure, known as the arcuate fasciculus, is smaller and less organized than in adults who read normally. However, it was unknown if these differences cause reading difficulties or result from lack of reading experience.”We were very interested in looking at children prior to reading instruction and whether you would see these kinds of differences,” says John Gabrieli, the Grover M. Hermann Professor of Health Sciences and Technology, professor of brain and cognitive sciences and a member of MIT’s McGovern Institute for Brain Research.Gabrieli and Nadine Gaab, an assistant professor of pediatrics at Boston Children’s Hospital, are the senior authors of a paper describing the results in the Aug. 14 issue of the Journal of Neuroscience. Lead authors of the paper are MIT postdocs Zeynep Saygin and Elizabeth Norton.The path to readingThe new study is part of a larger effort involving approximately 1,000 children at schools throughout Massachusetts and Rhode Island. At the beginning of kindergarten, children whose parents give permission to participate are assessed for pre-reading skills, such as being able to put words together from sounds.”From that, we’re able to provide — at the beginning of kindergarten — a snapshot of how that child’s pre-reading abilities look relative to others in their classroom or other peers, which is a real benefit to the child’s parents and teachers,” Norton says.The researchers then invite a subset of the children to come to MIT for brain imaging. The Journal of Neuroscience study included 40 children who had their brains scanned using a technique known as diffusion-weighted imaging, which is based on magnetic resonance imaging (MRI).This type of imaging reveals the size and organization of the brain’s white matter — bundles of nerves that carry information between brain regions. …

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New data reveal extent of genetic overlap between major mental disorders

Aug. 11, 2013 — The largest genome-wide study of its kind has determined how much five major mental illnesses are traceable to the same common inherited genetic variations. Researchers funded in part by the National Institutes of Health found that the overlap was highest between schizophrenia and bipolar disorder; moderate for bipolar disorder and depression and for ADHD and depression; and low between schizophrenia and autism. Overall, common genetic variation accounted for 17-28 percent of risk for the illnesses.”Since our study only looked at common gene variants, the total genetic overlap between the disorders is likely higher,” explained Naomi Wray, Ph.D., University of Queensland, Brisbane, Australia, who co-led the multi-site study by the Cross Disorders Group of the Psychiatric Genomics Consortium (PGC), which is supported by the NIH’s National Institute of Mental Health (NIMH). “Shared variants with smaller effects, rare variants, mutations, duplications, deletions, and gene-environment interactions also contribute to these illnesses.”Dr. Wray, Kenneth Kendler, M.D., of Virginia Commonwealth University, Richmond, Jordan Smoller, M.D., of Massachusetts General Hospital, Boston, and other members of the PGC group report on their findings August 11, 2013 in the journal Nature Genetics.”Such evidence quantifying shared genetic risk factors among traditional psychiatric diagnoses will help us move toward classification that will be more faithful to nature,” said Bruce Cuthbert, Ph.D., director of the NIMH Division of Adult Translational Research and Treatment Development and coordinator of the Institute’s Research Domain Criteria (RDoC) project, which is developing a mental disorders classification system for research based more on underlying causes.Earlier this year, PGC researchers — more than 300 scientists at 80 research centers in 20 countries — reported the first evidence of overlap between all five disorders. People with the disorders were more likely to have suspect variation at the same four chromosomal sites. But the extent of the overlap remained unclear. In the new study, they used the same genome-wide information and the largest data sets currently available to estimate the risk for the illnesses attributable to any of hundreds of thousands of sites of common variability in the genetic code across chromosomes. They looked for similarities in such genetic variation among several thousand people with each illness and compared them to controls — calculating the extent to which pairs of disorders are linked to the same genetic variants.The overlap in heritability attributable to common genetic variation was about 15 percent between schizophrenia and bipolar disorder, about 10 percent between bipolar disorder and depression, about 9 percent between schizophrenia and depression, and about 3 percent between schizophrenia and autism.The newfound molecular genetic evidence linking schizophrenia and depression, if replicated, could have important implications for diagnostics and research, say the researchers. …

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New study redefines how plaques grow in heart disease

Aug. 11, 2013 — The growth of deadly plaque inside the walls of arteries may not happen as scientists believed, research from the University of Toronto and Massachusetts General Hospital has found.The research also suggests a new potential target in the treatment of atherosclerosis, a leading cause of cardiovascular disease and death globally.The research team found that macrophages, white blood cells that drive atherosclerosis, replicate inside plaques. Moreover, this growth is not reliant on cells outside the plaques called monocytes, as scientists had assumed.”Until now, the thinking was that inflammatory macrophages arise mainly from the recruitment of their precursors — monocytes — from the bloodstream,” said Clint Robbins, lead author on the study and an Assistant Professor in U of T’s Departments of Laboratory Medicine and Pathobiology, and Immunology. “Our study shows that the accumulation of macrophages also depends on their proliferation locally within the developing plaque.”The journal Nature Medicine published the study results today.The impact of the research on clinical treatments could be large. Many pharmaceutical companies are pouring resources into potential therapies that can block the recruitment of white blood cells into plaques. But if macrophages self-sustain through local cell division, blocking recruitment may not be the best strategy.”I think this work will force some major re-evaluations,” said Filip Swirski, the study’s principal investigator who is a scientist in the Center for Systems Biology at Massachusetts General Hospital and an Assistant Professor at Harvard Medical School. “People have been thinking of targeting monocyte influx to treat atherosclerosis, but they need to consider macrophage proliferation as an additional or alternative approach, especially in established disease.”That approach might be better than targeting circulating monocytes, since interrupting disease-causing processes within plaques could spare other beneficial immune responses that monocytes control, said Swirski.As well, it could help improve the current standard of care in treating atherosclerosis: statin therapy. Statins, in addition to lowering blood lipids that contribute to plaque, have anti-inflammatory properties. The researchers are now looking at whether statins might limit the spread of macrophages within plaques.”Additional targeting of macrophage proliferation may further decrease inflammation in atherosclerosis and prove clinically advantageous,” said Robbins, who is also a scientist in the Toronto General Research Institute at University Health Network.The researchers conducted their study in mice, and they caution that much more research is needed to see how the work will translate to humans. But encouragingly, they found evidence of macrophage growth in plaques from human carotid arteries.Next, the team will compare macrophage proliferation to monocyte recruitment during different stages of atherosclerosis, and look at whether all macrophages, or only subsets, replicate.

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Placebo effects of different therapies not identical

July 31, 2013 — Not all placebos are equal, and patients who respond to one placebo don’t always respond to others, according to research published July 31 in the open access journal PLOS ONE by Jian Kong from Massachusetts General Hospital, Harvard Medical School and colleagues from other institutions.Share This:The researchers tested the analgesic effects of genuine acupuncture, sham acupuncture and a placebo pill on healthy participants’ pain sensitivity. Participants were not told what treatment they were receiving, but were informed that the pill was Tylenol, a well-known painkiller and different schools of acupuncture: electroacupuncture and manual acupuncture (sham acupuncture). A control group received no treatment at all. Shortly before and after each treatment, a warm electrode was placed on participants’ forearms and the temperature gradually increased. They were asked to indicate when the heat first became painful and when it became too hot to tolerate to identify pain thresholds and tolerance.No significant associations were found between participants’ responses to the different treatments, suggesting that none of these individuals could be identified as placebo ‘responders’ or ‘non-responders’. However, participants’ expectations that the treatment would help relieve pain correlated with their pain thresholds and tolerance.According to the authors, these and other parameters in their study suggest that responses to a placebo depend on diverse factors including the route of administration (pills or acupuncture), environmental cues, and learning based on verbal suggestions or conditioning. Kong adds, “It implies that placebo responses may not be dependent on stable individual traits but rather are more a characteristic of the circumstances of individuals or a combination of both trait and state.”In addition, they also found subjects’ responses to sham acupuncture correlated significantly with their response to genuine acupuncture. This suggest that people who responded to genuine acupuncture were significantly more likely to experience pain relief from sham acupuncture, but the authors clarify that this does not indicate the two are the same. Instead, they suggest that acupuncture may have non-specific pain-relieving effects that may contribute to this observation.Share this story on Facebook, Twitter, and Google:Other social bookmarking and sharing tools:|Story Source: The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length. …

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Stimulating brain cells can make false memories

Aug. 1, 2013 — Any crime scene investigator can tell you that memories are unreliable; the way people remember a place or event changes over time and varies between individuals. But for the mice in one lab at MIT, the accuracy of memories is even more suspect. Howard Hughes Medical Institute researchers in that lab have discovered how to alter the animals’ memories by turning on neurons in the brain that are associated with the memories and updating them with new information.The new findings, which appear in the journal Science, illustrate that a mouse can be made to fear a cage by giving it a foot shock while at the same time reactivating a memory of the cage to associate the two.”The kinds of things that once existed only in the realm of science fiction movies like Inception and Eternal Sunshine of the Spotless Mind are now experimentally possible,” says Steve Ramirez, a graduate student in the lab of HHMI investigator Susumu Tonegawa and first author of the new work.Researchers knew that memories are stored by the brain in a small set of neurons. Understanding how this information is encoded could be key to understanding how human memory works as well as memory disorders. But identifying exactly which neurons are linked to specific memories has been technically challenging.Ramirez and Tonegawa, along with Xu Liu, a postdoctoral fellow in Tonegawa’s lab at the Massachusetts Institute of Technology, had previously developed a way to pinpoint the specific handful of neurons that are activated in the brains of mice in any particular situation. The technique relies on optogenetics, a method of controlling brain cells through bursts of light developed by HHMI early career scientist Karl Deisseroth at Stanford University. The researchers engineered brain cells to produce a light-sensitive protein whenever the neurons were activated in a new setting or situation. Then, by shining a light onto the brain through a fiber optic cable connected to the mouse’s skull, they could reactivate only that subset of neurons. Even without reactivating the cells, they could determine which cells had been activated by measuring which contained the light-sensitive protein. …

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Cross-country collaboration leads to new leukemia model

July 31, 2013 — Eight years ago, two former Stanford University postdoctoral fellows, one of them still in California and the other at the Harvard Stem Cell Institute (HSCI) in Cambridge, began exchanging theories about why patients with leukemia stop producing healthy blood cells. What was it, they asked, that caused bone marrow to stop producing normal blood-producing cells?And after almost a decade of bicoastal collaboration, Emmanuelle Passegué, now a professor in the Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research at the University of California, San Francisco, and Amy Wagers, a professor in Harvard’s Department of Stem Cell and Regenerative Biology, have the answer.They have found that cancer stem cells actively remodel the environment of the bone marrow, where blood cells are formed, so that it is hospitable only to diseased cells. This finding could influence the effectiveness of bone marrow transplants, currently the only cure for late-stage leukemia, but with a 25 percent success rate due to repopulation of residual cancer cells.Their results, which were recently published online in Cell Stem Cell, show that leukemia cells cannot replicate in the bone marrow niche as well as healthy blood-forming stem cells can, so the cancer cells gain the advantage by triggering bone marrow-maintenance cells to deposit collagen and inflammatory proteins, leading to fibrosis — or scarring — of the bone marrow cavity.”They remodel the microenvironment so that it is basically callous, kicking the normal stem cells out of the bone marrow and encouraging the production of even more leukemic cells,” Passegué said. This model is a shift from the widely held theory that cancer cells simply crowd out the healthy cells.Passegué and Wagers stayed in touch, despite the distance between their laboratories, via annual, two-day, “off-the-record” symposiums of junior investigators at the Harvard Stem Cell Institute and the California Institute for Regenerative Medicine (CIRM). The meetings, which began in 2005 and have continued, require all registrants to keep presentations no longer than 15 minutes and only to discuss unpublished work. “It’s sort of Las Vegas rules,” Wagers said.At the second such meeting, Passegué was intrigued by Wagers’ cell isolation-based approach to studying the bone marrow niche, the environment where stem cells are found. In the ensuing years, the two scientists swapped protocols, chemical reagents, mice, and even postdoctoral researchers in the pursuit of discovering what causes healthy blood cell dysfunction in leukemia. “Wagers was really involved as a creative spirit in the development of this story,” Passegué said.The observation that leukemia cells can remodel the bone marrow niche parallels work done by HSCI co-director David Scadden of the Harvard-affiliated Massachusetts General Hospital, who demonstrated that particular genetic modifications of bone-forming cells initiate changes in the marrow cavity that suppress normal blood formation and promote the emergence of leukemic cells. “So there’s this bidirectional communication that’s self-reinforcing, “Wagers said. “And if there’s a communication loop like that, you can think about interrupting in many different ways.”Passegué wants to understand how bone-marrow support cells are manipulated to sustain leukemia cells, instead of normal blood cells, in order to design therapies that block these detrimental changes. …

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Genetic key to conquering cholera

July 19, 2013 — Researchers have long understood that genetics can play a role in how susceptible people are to contracting cholera, but a team of Harvard scientists is now uncovering evidence of genetic changes that might also help protect some people from contracting the deadly disease.Based on genetic data gathered from hundreds of people in Bangladesh, a research team made up of Harvard faculty and scientists from the Broad Institute and Massachusetts General Hospital were able to a number of areas in the genome — some of which are responsible for certain immune system functions, while others are related to fluid loss — that appear to be related to cholera resistance. Later tests showed genetic differences between people who had contracted the disease and those who had been exposed, but did not become ill. Their results are described in a paper published earlier this month in Science Translational Medicine.”This study is exceptionally exciting for us because it shows the power of this approach,” said Associate Professor of Organismic and Evolutionary Biology Pardis Sabeti, one of two senior co-authors of the paper. “This is the first time we’ve taken a genomic-wide approach to understanding cholera resistance. But it’s a first step, and there is a lot of exploration to go from here. For a disease that’s so ancient and widespread there’s very little that’s known about host immunity.”The hope, Sabeti added, is that by better understanding why some people appear to be immune, it will help in our efforts to develop vaccines and therapies, so outbreaks like those that occurred in recent years in Haiti and Africa might one-day be avoided.”It is a very scary disease,” she said. “We now have treatments with oral rehydration therapy, but it is still devastating, and in extreme cases, cholera can kill in hours.””We also haven’t been able to develop a particularly effective vaccine,” added Elinor Karlsson, a Post-Doctoral Fellow in Organismic and Evolutionary Biology, the first author of the paper. “The vaccine that’s available wears off after a few years, whereas people who are exposed to the disease develop a long-lasting immunity…and nobody is quite sure why that is. This research is another way of tackling that problem, and it’s a way no one has come at it before.”To understand the genetic differences between those with and without resistance, researchers first gathered genetic data on 42 family groups — called “trios” — that included a mother, father and child. Using that data, researchers identified more than 300 areas of the genome that appeared to be under pressure due to natural selection, suggesting that genes in those regions might be adapting to deal with the threat of cholera.”We found 305 areas — or about two percent of the genome — that appeared to be under selection,” Karlsson said. …

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Lizards show evolution is predictable

July 19, 2013 — If you could hit the reset button on evolution and start over, would essentially the same species appear? Yes, according to a study of Caribbean lizards by researchers at the University of California, Davis, Harvard University and the University of Massachusetts. The work is published July 19 in the journal Science.The predictability of evolution over timescales of millions of years has long been debated by biologists, said Luke Mahler, a postdoctoral fellow at UC Davis and first author on the paper. For example, the late Stephen Jay Gould predicted that if you “rewound the tape” on evolution and started over, you would get an entirely different outcome, arguing that small events — a storm that wiped out a particular pond, a poor season for insects — could have a disproportionate effect.On the other hand, there are a number of examples of species in similar habitats that evolve independently into similar-looking forms, such as the cichlid fishes of African lakes.”It’s a big question in evolutionary biology, but very hard to test,” Mahler said.Mahler found his test subjects in the Anole lizards that live on four neighboring islands — Cuba, Hispaniola (the countries of Haiti and the Dominican Republic), Jamaica and Puerto Rico. Anoles began colonizing these islands, all similar in climate and ecology, about 40 million years ago, and once there, they began to multiply, resulting in a diversity of species on each.The researchers studied 100 of the 119 Anole lizard species from the islands, taking measurements of their bodies from wild and museum specimens and comparing them across islands.They found a striking degree of convergence — on each island, evolution had produced a set of very similar-looking lizards occupying similar environmental niches.”The adaptive radiations match on all four islands — with few exceptions, each species on an island has a match on the other islands,” Mahler said.By combining the body-form data with a family tree of the Anoles, Mahler and colleagues were able to construct an “adaptive landscape” for the lizards. An adaptive landscape is a fundamental concept in evolutionary biology but difficult to show in practice. Peaks on an adaptive landscape represent various combinations of features that will be favored by natural selection, whereas valleys are just the opposite. Species with similar habits will tend to cluster on the same peak.For Anole lizards, their niche might be living on tree-trunks, or among twigs high in a tree, or down in the grasses on the ground. Each calls for different adaptations, and creates a different adaptive peak.The adaptive landscapes of all four islands are very similar, the researchers found. Looking back at the lizards’ evolutionary history, they were able to determine when a particular peak was colonized, or when a species hopped from one peak to another. …

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Complete description of gene expression in the human retina

July 18, 2013 — Investigators at Massachusetts Eye and Ear and Harvard Medical School have published the most thorough description of gene expression in the human retina reported to date. In a study published today in the journal BMC Genomics, Drs. Michael Farkas, Eric Pierce and colleagues in the Ocular Genomics Institute (OGI) at Mass. Eye and Ear reported a complete catalog of the genes expressed in the retina.The retina is the neural tissue in the back of the eye that initiates vision. It is responsible to receiving light signals, converting them into neurologic signals and sending those signals to the brain so that we can see. If one thinks of the eye as a camera, the retina in the “film” in the camera. For these studies, the investigators used a technique called RNA sequencing (RNA-seq) to identify all of the messenger RNAs (mRNAs) produced in the human retina. The resulting catalog of expressed genes, or transcriptome, demonstrates that the majority of the 20,000+ genes in the human body are expressed in the retina. This in itself is not surprising, because the retina is a complex tissue composed of 60 cell types.In a more surprising result, Dr. Farkas and colleagues identified almost 30,000 novel exons and over 100 potential novel genes that had not been identified previously. …

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