Archive for December 2009
Posted December 31, 2009on:
An international team of scientists led by researchers at The Scripps Research Institute has developed a straightforward technique to determine the ethnic origin of stem cells.
The Scripps Research scientists initiated the study—published in the January 2010 edition of the prestigious journal Nature Methods—because the availability of genetically diverse cell lines for cell replacement therapy and drug development could have important medical consequences. Research has shown that discordance between the ethnic origin of organ donors and recipients can influence medical outcomes for tissue transplantation, and that the safety and effectiveness of specific drugs can vary widely depending on ethnic background.
Advances in antiaging drugs, acoustic brain surgery, flu vaccines–and the secret to IQ.
For years, practitioners of alternative medicine have been touting the benefits of ginkgo, especially for maintaining brain health, but a new study finds that the centuries-old nostrum does little to slow the cognitive decline of aging.
Researchers at six universities across the U.S., led by Dr. Steven DeKosky at the University of Virginia School of Medicine, report that elderly people taking ginkgo supplements showed no notable differences in scores on brain-function tests from people taking placebo pills. The team, which published its results Tuesday, Dec. 29, in the Journal of the American Medical Association, tested volunteers on a range of tasks, including memory, attention, language, and visual and spatial constructions, and found that the extract from the ancient tree did little to slow the decline of these functions
The link between obesity and death from heart disease may be even worse than previously thought, but health problems associated with being underweight may have been exaggerated, a new study shows.
Previous studies have shown that a higher than normal body mass index (BMI), a barometer of unhealthy weight levels, is associated with higher rates of death from cardiovascular disease. Studies also have shown a link between being underweight, or having a low BMI, with increased mortality from such problems as respiratory disease and lung cancer.
But scientists at the University of Bristol in the U.K. and the Karolinska Institute in Sweden now say they’ve found that the risks of death from cardiovascular disease for people who are overweight or obese may have been understated, and the adverse consequences of having a low BMI have been overstated.
Two newly discovered genes may act as master control switches in the progression of the most aggressive form of brain cancer, glioblastoma.Researchers say the two genes are active in about 60% of all glioblastoma patients and identifying these genes could help identify those with this type of aggressive brain tumor.Glioblastoma is among the most lethal types of brain cancer because it rapidly spreads throughout the brain and creates inoperable brain tumors. Senator Edward Kennedy died of glioblastoma only 16 months after he was diagnosed with the disease.
The human brain works at a far higher level of complexity than previously thought. What has been given little attention up to now in the information processing of neuronal circuits has been the time factor. “Liquid computing” — a new theory about how these complex networks of nerve cells actually work from computer scientists at Graz University of Technology — has just passed its first test.
An interdisciplinary co-operation with neuroscientists from the Max-Planck Institute (MPI) for Brain Research in Frankfurt managed to show that early processing stages in the brain pool information over a longer period. For the evaluation of the experiments, the researchers also had to crack the neuronal code. Read the rest of this entry »
A new type of gene therapy may help stop the progression of emphysema in young people who have an inherited form of the deadly disease.
Researchers say previous attempts to correct the gene mutation that predisposes young people to emphysema have failed to achieve lasting results.
But a new study shows a different approach that targets cells known as alveolar macrophages to deliver the gene therapy to the lungs of mice with this form of inherited emphysema was successful in treating the condition for two years.
In a lab at the University of Pennsylvania, a plastic dish holds two rows of tiny black dots, pairs of them connected by dozens of thin, hairlike filaments. Each dot is a cluster of thousands of neurons, explains Douglas Smith, who is a professor of neurosurgery and the director of Penns Center for Brain Injury and Repair. The fibers that stretch between them actually comprise thousands of axons, long, slender projections that conduct electrical impulses away from each neurons central body. These bundles–each one a lab-engineered nerve–represent physical bridges that Smith hopes will help researchers like him mend previously irreparable injuries.
Platelets can quickly stanch the bleeding from a cut in your finger, but the hemorrhaging caused by a car crash or a battlefield injury might overwhelm the blood-clotting abilities of these cell fragments. Now, researchers report that they have designed a potential helper for such situations, a synthetic platelet that they show can curtail blood loss in animals.
After an injury, platelets stick to the walls of damaged vessels, to each other, and to clotting proteins, forming a plug. Platelet transfusions can boost clotting in trauma patients, wounded soldiers, and people with low platelet counts because of disease or cancer treatment. But platelets obtained from donated blood have several drawbacks, including a shelf life of only 5 days–versus 6 weeks for red blood cells–and a risk of bacterial infections.
Researchers have devised replacement platelets, such as red blood cells outfitted with a three-amino-acid sequence called RGD that natural platelets latch on to, thus potentially inducing a clot. So far, none of these alternatives has reached the emergency room. “If there was a suitable platelet substitute, that would be a tremendous achievement for clinical medicine,” says hematologist Marcel Levi of the University of Amsterdam in the Netherlands.
Platelet helper. Artificial platelets (green) crowd a blood clot.
CREDIT: J. BERTRAM ET AL., SCIENCE TRANSLATIONAL MEDICINE
Posted December 18, 2009on:
Two mice. One weighs 20 grams and has brown fur. The other is a hefty 60 grams with yellow fur and is prone to diabetes and cancer. They’re identical twins, with identical DNA
So what accounts for the differences?
It turns out that their varying traits are controlled by a mediator between nature and nurture known as epigenetics. A group of molecules that sit atop our DNA, the epigenome (which means “above the genome”) tells genes when to turn on and off. Duke University’s Randy Jirtle made one of the mice brown and one yellow by altering their epigenetics in utero through diet. The mother of the brown, thin mouse was given a dietary supplement of folic acid, vitamin B12 and other nutrients while pregnant, and the mother of the obese mouse was not. (Though the mice had different mothers, they’re genetically identical as a result of inbreeding.) The supplement “turned off” the agouti gene, which gives mice yellow coats and insatiable appetite
Scientists have unlocked the entire genetic code of two of the most common cancers – skin and lung – a move they say could revolutionise cancer care.
Not only will the cancer maps pave the way for blood tests to spot tumours far earlier, they will also yield new drug targets, says the Wellcome Trust team.
Scientists around the globe are now working to catalogue all the genes that go wrong in many types of human cancer.
The UK is looking at breast cancer, Japan at liver and India at mouth.
China is studying stomach cancer, and the US is looking at cancers of the brain, ovary and pancreas.
Taking a hint from natural antibiotics, a startup spun out of Stanford University is developing a way to chemically alter existing drugs to dramatically improve their half-life
By sequestering the drugs within cells, the researchers hope to protect them from the bodys efforts to destroy them. So far, the company has developed long-lasting versions of a protease inhibitor to fight HIV, as well as the antibiotic carbapenem. Amplyx is now developing new versions of a number of drugs that fight infection, and aims to test them in clinical trials within the next two years.
Hiding drugs: In this human blood smear, a modified protease inhibitor shown in green is sequestered inside a white blood cell. The cell’s DNA is shown in blue. The drug slowly leaches out into the plasma, greatly extending the drug’s half-life.Credit: Paul MerrinakResearchers at Amplyx Pharmaceuticals decorate drug compounds with molecules designed to bind to specific proteins within cells, as well as binding to the drugs treatment target.
Since the 1950s, researchers have been trying to mimic the abilities of red blood cells. These flexible discs carry oxygen throughout the body, squeezing through the smallest capillaries to do so. But the physical characteristics of red blood cells, including their doubly concave shape, have made them difficult to copy with precision.
In research published Monday in the Proceedings of the National Academy of Sciences, a group specializing in drug delivery has found a way to create biodegradable, biocompatible particles with the size, shape, and flexibility of red blood cells. The group believes these artificial cells might be particularly effective not just for carrying oxygen but also as therapeutic and imaging agents.
Every cup of coffee a person drinks per day may lower the risk of diabetes by 7%.
A new review of research on the link between lifestyle factors, like coffee and tea consumption, and diabetes risk suggests that drinking regular or decaffeinated coffee and tea all lower the risk of type 2 diabetes.
Ever since he first discovered the lifespan-extending effects of proteins called sirtuins 15 years ago, MIT Professor Leonard Guarente has been accumulating evidence to demonstrate a link between sirtuins and the effects of calorie restriction on lifespan.
For decades, it has been known that cutting normal calorie consumption by 30 to 40 percent can boost lifespan and improve overall health in animals such as worms and mice. Guarente believes that those effects are controlled by sirtuins — proteins that keep cells alive and healthy in the face of stress by coordinating a variety of hormonal networks, regulatory proteins and other genes.
In his latest work, published yesterday in the journal Genes and Development, Guarente adds to his case by reporting that sirtuins bring about the effects of calorie restriction on a brain system, known as the somatotropic signaling axis, that controls growth and influences lifespan length.
Unlike most researchers, the engineers at ImThera Medical just might consider it a compliment if someone called their product a “snooze.” The experimental device is designed to treat sleep apnea, a breathing disorder that can disrupt sleep and trigger serious complications, including an increased risk for heart disease and stroke, as well as daytime sleepiness so severe that sufferers often fall asleep at the wheel. The implant, which wraps around a nerve connected to the tongue, is now being tested in a small clinical trial in Europe.
gene which is essential for stem cells’ capabilities to become any cell type has been identified by researchers at the Hebrew University of Jerusalem and the University of California, San Francisco.
The discovery represents a further step in the ever-expanding field of understanding the ways in which stem cells develop into specific cells, a necessary prelude towards the use of stem cell therapy as a means to reverse the consequences of disease and disability. Read the rest of this entry »
Posted December 14, 2009on:
Scientists have resolved a question about how a popular class of drugs used to treat schizophrenia works using biosensors that reveal previously hidden components of chemical communication in the brain.
A previously incurable blood disorder – sickle-cell disease – has been successfully treated in 9 of 10 adults who received stem cells transplanted from tissue-matched siblings.
Posted December 13, 2009on:
Researchers at Yale have demonstrated a device that uses a magnetic liquid to separate blood cells based on their size and shape in just minutes.The device applies a magnetic field to a liquid containing magnetic nanoparticles. The nanoparticles create waves that carry cells along depending on their size, shape and mechanical properties. The researchers, led by electrical engineering professor Hur Koser, hope to develop a cheap alternative to cell-sorting techniques that are time-consuming and sometimes require expensive labeling.
A team of Princeton University scientists has produced a systematic listing of the ways a particular cancerous cell has “gone wrong,” giving researchers a powerful tool that eventually could make possible new, more targeted therapies for patients.
What would happen if some soft tissue cells in your body randomly got the message to transform into stiff bone cells? Patients born with a disease called fibrodysplasia ossificans progressiva (FOP) are locked into this fate, often becoming severely disabled before adulthood.
The disease first manifests itself at birth, when a baby appears normal but has bent big toes. By early childhood, however, some of the body’s connective tissues—including muscles, ligaments and tendons—have begun ossifying into skeletal bone, locking the joints and distorting posture and movement. Some bone formation appears to be spontaneous, while some can be brought on by trauma from surgery or even a mild impact.
If youve been diagnosed with breast cancer, you may want to cut down on alcoholic beverages.Thats the suggestion of researchers who found that cancer is 34% more likely to come back in breast cancer survivors who drink more than three drinks a week, compared with those who abstain or drink less.Drinking more than three drinks a week also raised the risk of dying from breast cancer by 51%, says Marilyn L. Kwan, PhD, a staff scientist at Kaiser Permanente in Oakland, Calif.
Scientists at New York University report they have developed a drug-free, noninvasive way to temporarily block the return of fearful memories in people.
The technique, the researchers contend, could eventually change the way scientists view how the brain’s memory storage process works and perhaps even lead to new ways to treat anxiety disorders, including posttraumatic stress disorder.
Researcher Daniela Schiller, PhD, and colleagues at NYU say in a new study published in the journal Nature that they’ve been able to reshape memories. The process involves resurrecting unpleasant memories and creating a window of opportunity for reshaping the fears, a period called “reconsolidation.”
Scientists have discovered a new type of stem cell in the skin that acts surprisingly like certain stem cells found in embryos: both can generate fat, bone, cartilage, and even nerve cells. These newly-described dermal stem cells may one day prove useful for treating neurological disorders and persistent wounds, such as diabetic ulcers, says Freda Miller, an HHMI international research scholar. Read the rest of this entry »
Giving women more of the male hormone testosterone can turn them into fairer and more amiable game players, according to tests.A single dose of testosterone was enough to have this effect, European scientists found, but only if the woman was oblivious to the treatment.If she realised she had received the hormone and not a dummy drug, she turned to greed and selfishness.
The work in Nature magazine suggests the mind can win over hormones.Testosterone induces anti-social behaviour in humans, but only because of our own prejudices about its effect rather than its biological activity, suggest the authors.
They believe the same is true in men, although they only studied women.
Besides treating depression, the antidepressant Paxil may affect personality traits in positive ways, a new study suggests.
Researchers say Paxil and likely other antidepressants in the class of drugs called selective serotonin reuptake inhibitors (SSRIs) may improve higher levels of neuroticism and lower levels of extraversion that are commonly seen with depression.
Neuroticism is characterized as being inclined to have negative emotions such as anxiety, hostility, self-consciousness, impulsivity, and sensitivity to stress.
Extraversion refers to being inclined to have positive emotions, assertiveness, and gregariousness.
Drinking coffee regularly may help lower the risk of advanced prostate cancer, a study shows.
The study, presented this week at a conference of the American Association for Cancer Research in Houston, shows men who drank the most coffee were nearly 60% less likely to develop advanced prostate cancer than non-coffee drinkers.
Researchers say it's too early to start recommending that men start drinking coffee to help prevent prostate cancer, but the results are encouraging.
Moderate intake of soy foods by breast cancer survivors appears to be not only safe but beneficial, according to a new study.Women who had a higher soy intake had a lower mortality and lower risk of relapse [than women with a low intake],” says researcher Xiao Ou Shu, MD, PhD, professor of medicine at Vanderbilt University Medical Center in Nashville, Tenn.Previous research has yielded conflicting findings, with some studies finding that soy foods reduce breast cancer risk but others finding that genistein, an estrogen-like compound known as an isoflavone in soy, helps breast cancer cells grow in the lab and promotes tumor growth in animals.
Healthy levels of vitamin D may help patients with a certain type of non-Hodgkin's lymphoma live longer.
Researchers at the Mayo Clinic have discovered that patients with diffuse large B-cell lymphoma (DLBCL) and low vitamin D levels are two times more likely to die from the cancer than patients with optimal levels. Deficient vitamin D levels also increased the chances of cancer progression.
An experimental drug developed by Danish startup Santaris effectively controls the hepatitis C virus in chimpanzees without creating drug-resistant forms of the virus–a major advantage over other compounds in clinical development. The compound, a synthetic nucleic acid that binds to a microRNA molecule required for viral reproduction, is now in early-stage clinical trials. It is the first microRNA-targeting drug to be tested in humans.
A new study of the Max Planck Institute for Biology of Ageing could help to understand the positive effect of dietary restriction on healthy ageing. Previous evidence from different organisms (fruit flies and mice) have shown that dietary restriction increases longevity, but with a potential negative side effect of diminished fertility. So the female fruit fly reproduces less frequently with a reduced litter size on a low calorie diet, but its reproductive span lasts longer. This is the result of an evolutionary trait, as scientists believe: essential nutrients are diverted towards survival instead of reproduction. (Nature, December 3, 2009) Read the rest of this entry »
The body is a battle zone. Cells constantly compete with one another for space and dominance. Though the manner in which some cells win this competition is well known to be the survival of the fittest, how stem cells duke it out for space and survival is not as clear. A study on fruit flies published in the October 2 issue of Science by Johns Hopkins researchers describes how stem cells win this battle by literally sticking around. Read the rest of this entry »
Researchers from Yale University and Mirna Therapeutics, Inc., reversed the growth of lung tumors in mice using a naturally occurring tumor suppressor microRNA. The study reveals that a tiny bit of RNA may one day play a big role in cancer treatment, and provides hope for future patients battling one of the most prevalent and difficult to treat cancers. Read the rest of this entry »
The electroencephalogram (EEG) has been widely used in research and medicine for more than eighty years. The ability to measure the electric activity in the brain by means of electrodes on the head is a handy tool to study brain functions as it is noninvasive and easy to apply. However, the interpretation of the EEG signals remains difficult. The main reason for this is that the exact relationship between the activities generated in the brain to that measured on the scalp is unclear. Read the rest of this entry »
In the first study to demonstrate a clear positive association between adolescent fitness and adult cognitive performance, Nancy Pedersen of the University of Southern California and colleagues in Sweden find that better cardiovascular health among teenage boys correlates to higher scores on a range of intelligence tests – and more education and income later in life. Read the rest of this entry »
A desktop instrument recently approved by the U.S. Food and Drug Administration might finally bring pharmacogenomic testing–the use of a patients genetic information for drug prescription decisions–to the mainstream. The device, made by Nanosphere, a startup based in Northbrook, IL, can, in a matter of hours, detect genetic variations in blood that modulate the effectiveness of some drugs. Dubbed Verigene, the technology employs a combination of microfluidics and nanotechnology, housed in a single plastic cartridge, to pull DNA from a blood sample and then screen it for the relevant sequences.
Previous studies have shown a link between low vitamin D status and heart disease. Now a new study shows that patients with high blood pressure who possess a gene variant that affects an enzyme critical to normal vitamin D activation are twice as likely as those without the variant to have congestive heart failure. Read the rest of this entry »
Scientists have long known that the human immune system has a method for detecting and destroying precancerous cells. But finding the cells behind this defense mechanism in order to study and perhaps even mimic them has proved quite the challenge. Since the malignant precancerous cells are eradicated before we even know they exist, identifying the cells that killed them seemed nearly impossible. Now European researchers have built a microfluidic biosensor that traps single immune cells together with single tumor cells, allowing the researchers to pick the most potent of these cancer killers out of a crowded field.
Can stem cells safely repair heart attack damage? Yes, a clinical trial suggests.Bone marrow stem cells are supposed to home in on damaged parts of the heart. Once there, they send out signals that help the body repair the injury. Theres also evidence, from animal studies, that the stem cells themselves engraft to the heart and help repopulate dead cells with new, living cells.Now theres evidence from actual patients who suffered heart attacks.
Nanoparticles that deliver two or more drugs simultaneously can significantly shrink pancreatic cancer tumors and also reduce its spread, say researchers at Massachusetts General Hospital. Tayyaba Hasan, who is also a professor of dermatology at Harvard Medical School, led the development and testing of two “nanocells.” These nanocells combine light-based therapy with molecules that inhibit the growth of cancer cells or of the blood vessels that feed them.
Though the particles have only been studied in mice so far, the cancer-research community is excited. Pancreatic cancer remains one of the deadliest and hardest cancers to treat; mortality rates have changed very little in the last 30 years. After diagnosis, patients tend to live only six months, and less than 5 percent survive for five years. “In terms of a patient population, there is very little we can do for them once we find the cancer,” says Craig Thompson, director of the Abramson Cancer Center at the University of Pennsylvania.
A healthy body may be the first step to achieving a healthy mind and appetite for learning.
A large new study links cardiovascular fitness in early adulthood to increased intelligence, better performance on cognitive tests, and higher educational achievement later in life.
Researchers say the results suggest that promoting physical and cardiovascular fitness as a public health strategy could maximize educational achievement as well as prevent disease at the societal level.