Archive for May 2012
Researchers have shown in mice how immune cells in the brain target and remove unused connections between brain cells during normal development. This research, supported by the National Institutes of Health, sheds light on how brain activity influences brain development, and highlights the newly found importance of the immune system in how the brain is wired, as well as how the brain forms new connections throughout life in response to change.
Disease-fighting cells in the brain, known as microglia, can prune the billions of tiny connections (or synapses) between neurons, the brain cells that transmit information through electric and chemical signals. This new research demonstrates that microglia respond to neuronal activity to select synapses to prune, and shows how this pruning relies on an immune response pathway – the complement system – to eliminate synapses in the way that bacterial cells or other pathogenic debris are eliminated. The study was led by Beth Stevens, Ph.D., assistant professor of neurology at Boston Children’s Hospital and Harvard Medical School.
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Researchers at New York University and Albert Einstein College of Medicine of Yeshiva University have discovered new ways neurons work together to ease the transition between sleep and wakefulness. Their findings, which appear in the journal Neuron, provide additional insights into sleep-wake patterns and offer methods to explore what may disrupt them.
Their study explored the biological, or circadian, clocks of Drosophila fruit flies, which are commonly used for research in this area. This is because it is relatively easy to find mutants with malfunctioning biological clocks and then to identify the genes underlying the altered behavior. Such studies in fruit flies have allowed the identification of similar “clock genes” in mammals, which function in largely the same manner as they do in a fly’s clock. Read the rest of this entry »
In a medical first, scientists in Haifa, Israel, took skin cells from two heart failure patients and reprogrammed them into stem cells that generated healthy, beating heart muscle cells in the lab. Though human testing is likely a decade off, the hope is that such cells can be used to help people with heart failure repair their damaged hearts with their own skin cells.
In the current study, scientists first mixed the newly developed heart cells with pre-existing heart tissue — within days, the cells were beating together. The heart tissue was then transplanted into rats, where it integrated with the rats’ healthy heart cells.
DR. JOHN D. CUNNINGHAM / GETTY IMAGES
HIV patients treated with genetically modified T cells remain healthy up to 11 years after initial therapy, researchers from the Perelman School of Medicine at the University of Pennsylvania report in the new issue of Science Translational Medicine. The results provide a framework for the use of this type of gene therapy as a powerful weapon in the treatment of HIV, cancer, and a wide variety of other diseases.
“We have 43 patients and they are all healthy,” says senior author Carl June, MD, a professor of Pathology and Laboratory Medicine at Penn Medicine. “And out of those, 41 patients show long term persistence of the modified T cells in their bodies.” Read the rest of this entry »
Older adults who drank coffee — caffeinated or decaffeinated — had a lower risk of death overall than others who did not drink coffee, according a study by researchers from the National Cancer Institute (NCI), part of the National Institutes of Health, and AARP.
Coffee drinkers were less likely to die from heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections, although the association was not seen for cancer. These results from a large study of older adults were observed after adjustment for the effects of other risk factors on mortality, such as smoking and alcohol consumption. Researchers caution, however, that they can’t be sure whether these associations mean that drinking coffee actually makes people live longer. The results of the study were published in the May 17, 2012 edition of the New England Journal of Medicine. Read the rest of this entry »
A study from Massachusetts General Hospital (MGH) researchers suggests that specific populations of tumor cells have different roles in the process by which tumors make new copies of themselves and grow. In their report in the May 15 issue of Cancer Cell, researchers identify a tumor-propagating cell required for the growth of a pediatric muscle tumor in a zebrafish model and also show that another, more-differentiated tumor cell must first travel to sites of new tumor growth to prepare an environment that supports metastatic growth.
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For decades, scientists have studied Caenorhabditis elegans – tiny, transparent worms – to glean clues about how neurons develop and function. A new Harvard study suggests that the worms’ nervous system is much more capable and complex than previously thought, and has a way to monitor its own motion, a model one day could serve to develop treatments for disorders like schizophrenia.
While most research into the worms’ neurons has shown that each performs as a single functional unit, Yun Zhang, Associate Professor of Organismic and Evolutionary Biology and Center for Brain Science, together with her colleagues Michael Hendricks, Heonick Ha and Nicolas Maffey, has uncovered evidence that, in some neurons, different compartments of a single neuron exhibit activities independently of each other. These local activities within the individual neurites represent self-motion signals and control movement. The work is described in a paper published on May 13 in Nature.
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A novel mechanism for anxiety behaviors, including a previously unrecognized inhibitory brain signal, may inspire new strategies for treating psychiatric disorders, University of Chicago researchers report.
By testing the controversial role of a gene called Glo1 in anxiety, scientists uncovered a new inhibitory factor in the brain: the metabolic by-product methylglyoxal. The system offers a tantalizing new target for drugs designed to treat conditions such as anxiety disorder, epilepsy, and sleep disorders.
The study, published in the Journal of Clinical Investigation, found that animals with multiple copies of the Glo1 gene were more likely to exhibit anxiety-like behavior in laboratory tests. Further experiments showed that Glo1 increased anxiety-like behavior by lowering levels of methylglyoxal (MG). Conversely, inhibiting Glo1 or raising MG levels reduced anxiety behaviors. Read the rest of this entry »
Researchers have identified a compound that could correct a mutation and stop cancer from spreading — a development that could eventually be used to treat tens of thousands of cancer patients in the United States each year.
In a study published today in the journal Cancer Cell, four scientists from the Cancer Institute of New Jersey and the Institute for Advanced Study laid out their work involving a compound that corrects a mutation in the valuable p53 protein — “a kind of common denominator” in a wide ranger of cancers, including ovarian, pancreatic, breast, lung, esophageal and others.
The p53 protein is a kind of intracellular security force that cracks down on cells when they go rogue, but which is hijacked by cancer, allowing malignant cells to spread.
The compounds tested — called thiosemicarbazones — have been intermittently investigated as cancer-fighters for decades, but are only now being singled out as a treatment for a specific group of cancers. The researchers found the compounds shrank or slowed the growth of tumor cells in mice.
Medicine’s focus has long been on treating specific diseases. We have radiation treatments to combat cancer tumors, cholesterol-lowering drugs to stave off heart attacks, and insulin to control diabetes.
But imagine if there were a drug that would slow down the aging process itself, a drug that didn’t just treat a single disease but instead targeted multiple diseases of old age at once? It may sound far-fetched, but that’s precisely what longevity scientists are working hard to produce.
“It’s not just that we’re trying to make people live longer; we’re trying to make people live healthier. This is an exciting time for research,” says Felipe Sierra, director of the Division of Aging Biology at the National Institute on Aging.
Indeed, top-notch research labs are rolling out studies at a rapid rate, and a growing chorus of experts believe the advances being made will ultimately lead to a crop of drugs capable of extending healthy lifespans. Signs of progress are abundant in medical journals.
Posted May 14, 2012on:
A group of American researchers from MIT, Indiana University, and Tufts University, led by Erin Treacy Solovey, have developed Brainput — pronounced brain-put, not bra-input — a system that can detect when your brain is trying to multitask, and offload some of that workload to a computer.
The idea of using computers to do our grunt work isn’t exactly new — without them, the internet wouldn’t exist, manufacturing would be a very different beast, and we’d all have to get a lot better at mental arithmetic. I would say that the development of cheap, general purpose computers over the last 50 years, and the freedoms they have granted us, is one of mankind’s most important advancements. Brainput is something else entirely though.
Using functional near-infrared spectroscopy (fNIRS), which is basically a portable, poor man’s version of fMRI, Brainput measures the activity of your brain. This data is analyzed, and if Brainput detects that you’re multitasking, the software kicks in and helps you out. In the case of the Brainput research paper, Solovey and her team set up a maze with two remotely controlled robots. The operator, equipped with fNIRS headgear, has to navigate both robots through the maze simultaneously, constantly switching back and forth between them. When Brainput detects that the driver is multitasking, it tells the robots to use their own sensors to help with navigation. Overall, with Brainput turned on, operator performance improved — and yet they didn’t generally notice that the robots were partially autonomous.
Positive emotions like joy and compassion are good for your mental and physical health, and help foster creativity and friendship. But people with bipolar disorder seem to have too much of a good thing. In a new article to be published in the August issue of Current Directions in Psychological Science, a journal of the Association for Psychological Science, psychologist June Gruber of Yale University considers how positive emotion may become negative in bipolar disorder.
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Humans walk on two feet and (mostly) lack hair-covered bodies, but the feature that sets us furthest apart from other apes is a brain capable of language, art, science, and other trappings of civilisation.
Now, two studies published online today in Cell1, 2 suggest that DNA duplication errors that happened millions of years ago might have had a pivotal role in the evolution of the complexity of the human brain. The duplications — which created new versions of a gene active in the brains of other mammals — may have endowed humans with brains that could create more neuronal connections, perhaps leading to greater computational power.
ANN CUTTING / GETTY IMAGES
A pill that has long been used to treat HIV has moved one step closer to becoming the first drug approved to prevent healthy people from becoming infected with the virus that causes AIDS.
The Food and Drug Administration said Tuesday that Gilead Sciences’ Truvada appears to be safe and effective for HIV prevention. It concluded that taking the pill daily could spare patients “infection with a serious and life-threatening illness that requires lifelong treatment.”
On Thursday a panel of FDA advisers will consider the review when it votes on whether Truvada should be approved as a preventative treatment for people who are at high risk of contracting HIV through sexual intercourse. The FDA is not required to follow the advice of its panels, but it usually does.
Chemotherapy saves lives, but it can take a considerable toll on the body. Now, by inserting a mutated gene into cancer patients, researchers have found a way to protect them against the side effects of chemotherapy and boost their odds of surviving a particularly aggressive type of cancer.
Patients with glioblastoma, a fast-growing and usually fatal brain cancer, face overwhelming odds. Half die within 13 months of diagnosis, and very few survive long-term. Treatment is part of the problem. Many glioblastomas are resistant to chemotherapy because they harbor an overactive gene called MGMT, which repairs the cancer cells after chemotherapy damages them. To counteract the gene, physicians sometimes add an MGMT-blocking drug, benzylguanine, to the chemotherapy regimen to make the cancer cells easier to kill. But benzylguanine also makes healthy blood and bone marrow cells easy to kill.
To find a way around these severe side effects, Kiem and colleagues zeroed in on a mutated version of MGMT called P140K. The gene enables cells to resist chemotherapy and benzylguanine. The team wondered what would happen if healthy cells had P140K.
The typical naked mole rat lives 25 to 30 years, during which it shows little decline in activity, bone health, reproductive capacity and cognitive ability. What is the secret to this East African rodent’s long, healthy life?
Scientists from the United States and Israel found a clue. From infancy to old age, naked mole rats are blessed with large amounts of a protein essential for normal brain function.
“Naked mole rats have the highest level of a growth factor called NRG-1 in the cerebellum. Its levels are sustained throughout their life, from development through adulthood,” said Yael Edrey, doctoral student at The University of Texas Health Science Center San Antonio’s Barshop Institute for Longevity and Aging Studies.
Magnet-making bacteria may be building biological computers of the future, researchers have said.
A team from the UK’s University of Leeds and Japan’s Tokyo University of Agriculture and Technology have used microbes that eat iron. As they ingest the iron, the microbes create tiny magnets inside themselves, similar to those in PC hard drives.
The research may lead to the creation of much faster hard drives, the team of scientists say. The study appears in the journal Small.
As technology progresses and computer components get smaller and smaller, it becomes harder to produce electronics on a nano-scale. So researchers are now turning to nature – and getting microbes involved.
Tiny magnets form inside magnetic bacteria
Posted May 7, 2012on:
If you’re counting calories to lose weight, that may be only part of the weight loss equation says a new research report published online in The FASEB Journal (http://www.fasebj.org). In the report, French scientists show that impairments to a gene known to be responsible for our internal body clocks, called “Rev-Erb alpha,” leads to excessive weight gain and related health problems. This provides new insights into the importance of proper alignment between the body’s internal timing and natural environmental light cycles to prevent or limit excessive weight gain and the problems this weight gain causes.
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British researchers writing in the journal Nature said they had found a major pathway leading to brain cell death in mice with prion disease, the mouse equivalent of Creutzfeld-Jacob Disease (CJD).
They then worked out how to block it, and were able to prevent brain cells from dying, helping the mice live longer.
The finding, described by one expert as “a major breakthrough in understanding what kills neurons”, points to a common mechanism by which brain diseases such as Alzheimer’s, Parkinson’s and CJD damage the nerve cells.
In neurodegenerative diseases, proteins “mis-fold” in a various ways, leading to a buildup of misshapen proteins, the researchers explained in the study.
These misshapen proteins form the plaques found in the brains of patients with Alzheimer’s and the Lewy bodies found in Parkinson’s disease
Researchers have remotely activated genes inside living animals, a proof of concept that could one day lead to medical procedures in which patients’ genes are triggered on demand.
The work, in which a team used radio waves to switch on engineered insulin-producing genes in mice, is published today in Science1.
Jeffrey Friedman, a molecular geneticist at the Rockefeller University in New York and lead author of the study, says that in the short term, the results will lead to better tools to allow scientists to manipulate cells non-invasively. But with refinement, he thinks, clinical applications could also be possible.
Nanoparticles induced cell excitation to increase insulin expression and release in vitro (credit: Sarah A. Stanley et al./Science)
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Gaining access to the inner workings of a neuron in the living brain offers a wealth of useful information: its patterns of electrical activity, its shape, even a profile of which genes are turned on at a given moment. However, achieving this entry is such a painstaking task that it is considered an art form; it is so difficult to learn that only a small number of labs in the world practice it.
But that could soon change: Researchers at MIT and Georgia Tech have developed a way to automate the process of finding and recording information from neurons in the living brain. The researchers have shown that a robotic arm guided by a cell-detecting computer algorithm can identify and record from neurons in the living mouse brain with better accuracy and speed than a human experimenter.
The new automated process eliminates the need for months of training and provides long-sought information about living cells’ activities. Using this technique, scientists could classify the thousands of different types of cells in the brain, map how they connect to each other, and figure out how diseased cells differ from normal cells.
Graphic coutresy of the Boyden Lab
Worrywarts, fidgety folk and the naturally nervy may have a real cause for concern: accelerated cancer. In a new study led by researchers at the Stanford University School of Medicine, anxiety-prone mice developed more severe cancer then their calm counterparts.
The study, to be published online April 25 in PLoS ONE, found that after hairless mice were dosed with ultraviolet rays, the nervous ones — with a penchant for reticence and risk aversion — developed more tumors and invasive cancer. Consistent anxiety also came with sensitivity to chronic stress and a dampened immune system. Though other researchers have already linked chronic stress to higher risks for cancer and other maladies, the study is the first to biologically connect the personality trait of high anxiety to greater cancer threats.
Researchers have rejuvenated aged hematopoietic stem cells to be functionally younger, offering intriguing clues into how medicine might one day fend off some ailments of old age.
Scientists at Cincinnati Children’s Hospital Medical Center and the Ulm University Medicine in Germany report their findings online May 3 in the journal Cell Stem Cell. The paper brings new perspective to what has been a life science controversy — countering what used to be broad consensus that the aging of hematopoietic stem cells (HSCs) was locked in by nature and not reversible by therapeutic intervention. Read the rest of this entry »
The U.S. government is looking for the next AZT, Viagra and thalidomide — substances that washed out as treatments for one disease but later turned out to work well against a totally different ailment.
AZT failed as a cancer drug but became the first antiviral to work against HIV. Viagra didn’t succeed as a treatment for angina but turned out to be great against impotence. Thalidomide, the notorious morning sickness pill that caused thousands of birth defects in Europe, is a treatment for leprosy and multiple myeloma.
Whether someone is a “go-getter” or a “slacker” may depend on individual differences in the brain chemical dopamine, according to new research in the May 2 issue of The Journal of Neuroscience. The findings suggest that dopamine affects cost-benefit analyses.
The study found that people who chose to put in more effort — even in the face of long odds — showed greater dopamine response in the striatum and ventromedial prefrontal cortex, areas of the brain important in reward and motivation. In contrast, those who were least likely to expend effort showed increased dopamine response in the insula, a brain region involved in perception, social behavior, and self-awareness. Read the rest of this entry »
The first blind patients to be fitted with electronic eye implants in a UK clinical trial have regained “useful vision” only weeks after surgery.
Chris James was able to see outlines of objects for the first time in 20 years after surgeons fitted him with the device during an eight-hour operation.
The 51-year-old from Wiltshire, who lost his sight to the disease retinitis pigmentosa (RP), is one of two patients taking part in the first UK trial of the technology that began in April.
Doctors said that both patients showed improvements in their eyesight that “exceeded expectations”
Researchers have found new evidence showing that resveratrol, a compound found in red wine, may play a role in preventing cell aging.
The study in rodents found that when mice had a particular gene — SIRT1 — knocked out, or turned off, resveratrol had no effect on them. But tests of muscle tissue in mice with a normal SIRT1 gene that were given resveratrol found that the substance boosted mitochondrial function.
Mitochondria provide the energy that cells need to function. A decrease in mitochondrial energy production has been linked to a variety of diseases, including diabetes and Alzheimer’s disease, as well as to the aging process itself, said senior study author David Sinclair, a professor of genetics at Harvard Medical School in Boston.
But don’t go reaching for that Chianti yet. Yes, resveratrol is found in the skin of red grapes. But “the amounts we gave to our mice would be like drinking 100 glasses of red wine a day,” Sinclair said.
Instead, the goal is to develop synthetic resveratrol compounds that activate SIRT1 and could be taken as medication. “My colleagues are in the middle of developing better molecules that we hope will be medicines that will be used to treat diseases of aging, not to extend lifespan, though that may be a side effect,” Sinclair said.