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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