Archive for March 2011
Posted March 27, 2011on:
Until now, there have been no witnesses to the death of brain cells in people with Parkinson’s disease.
And like any murder mystery, this has slowed the search for the killer.
In a big break in the case, Stanford University scientists say they have re-enacted this tragedy in a petri dish — growing the young neurons from the donated skin cells of Parkinson’s patient Genia Brin, the mother of Google co-founder Sergey Brin — and then watching them sicken and perish.
This feat, co-authored in this month’s issue of the journal Cell by Stanford’s Renee Reijo Pera, could accelerate the search for a cure of the crippling disorder. The research makes it possible, for the first time in medical history, to study the diseased cells and test compounds that might slow or even prevent their development.
“For the first time ever, we have them in a dish where we can study them directly. We can see exactly why they’re dying, and test drugs in them,” said Dr. William Langston of the Sunnyvale-based Parkinson’s Institute, who contributed to the effort.
Posted March 27, 2011on:
There are billions of neurons in the brain and at any given time tens of thousands of these neurons might be trying to send signals to one another. Much like a person trying to be heard by his friend across a crowded room, neurons must figure out the best way to get their message heard above the din.
Researchers from the Center for the Neural Basis of Cognition, a joint program between Carnegie Mellon University and the University of Pittsburgh, have found two ways that neurons accomplish this, establishing a fundamental mechanism by which neurons communicate. The findings have been published in an online early edition of Proceedings of the National Academy of Sciences (PNAS).
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Researchers have developed a way to create uniformly sized cell membranes, small cellular packages that can be used like tiny terrariums to study the inner workings of the cell and even create new molecules.
Sandro Matosevic and Brian Paegel of the Scripps Research Institute in Jupiter, Florida, have developed a chip-based method that creates uniformly sized vesicles in assembly-line fashion. Sized between 20 and 70 micrometers in diameter, the vesicles are large enough to be loaded with DNA and the biochemical machinery to act as synthetic cells. The synthetic packaging will help researchers study the proteins in cell membranes, which play important roles as gatekeepers of the cell. Many drugs, for example, act on these membrane proteins or otherwise use them to get inside cells in order to do their job.
Islands in the stream: Water droplets suspended in oil travel down a channel in a microfluidic chip. A stream of water flows alongside, forming an oil-water interface.
Credit: Brian Paegel lab, Scripps Institute
A sleepless night can make us cranky and moody. But a lesser known side effect of sleep deprivation is short-term euphoria, which can potentially lead to poor judgment and addictive behavior, according to new research from the University of California, Berkeley.
Researchers at UC Berkeley and Harvard Medical School studied the brains of healthy young adults and found that their pleasure circuitry got a big boost after a missed night’s sleep. But that same neural pathway that stimulates feelings of euphoria, reward and motivation after a sleepless night may also lead to risky behavior, their study suggests.
By mutating a single gene, researchers at MIT and Duke have produced mice with two of the most common traits of autism — compulsive, repetitive behavior and avoidance of social interaction.
They further showed that this gene, which is also implicated in many cases of human autism, appears to produce autistic behavior by interfering with communication between brain cells. The finding, reported in the March 20 online edition of Nature, could help researchers find new pathways for developing drugs to treat autism, says senior author Guoping Feng, professor of brain and cognitive sciences and member of the McGovern Institute for Brain Research at MIT.
A novel approach to pancreatic cancer treatment that activates the immune system works in some patients, according to a new study.
The treatment works by destroying the ”scaffolding” around cancer cells, says researcher Robert H. Vonderheide, MD, DPhil, an associate professor of medicine in the division of hematology/oncology and the Abramson Family Cancer Research Institute, University of Pennsylvania.
“The therapy is an antibody,” he says. ”Instead of binding to the cancer, this antibody binds to a molecule in the immune system, and that is CD40,” he tells WebMD. Next, the immune system is activated, allowing it to attack the so-called scaffolding around the cancer cells. The scaffolding is destroyed and the tumor falls apart.
The process is somewhat like attacking a brick wall by dissolving the mortar in the wall, he says.
By comparing the genome sequence of healthy and cancerous cells in 38 people diagnosed with multiple myeloma—an aggressive blood cancer—scientists have created a molecular map of what goes awry in this disease.
The findings, published today in Nature, point to new targets for drug development, and also suggest that some patients will respond to drugs currently being tested for other types of cancers.
The study is also the first published analysis of multiple whole genomes of the same cancer, reflecting continuing advances in sequencing technologies and the ability to analyze whole-genome data.
Biological systems, including cells, tissues and organs, can function properly only when their parts are working in harmony. These systems are often dauntingly complex: Inside a single cell, thousands of proteins interact with each other to determine how the cell will develop and respond to its environment.
To understand this great complexity, a growing number of biologists and bioengineers are turning to computational models. This approach, known as systems biology, has been used successfully to model the behavior of cells grown in laboratory dishes. However, until now, no one has used it to model the behavior of cells inside a living animal.
Researchers in Japan have made fertile mammalian sperm in a culture dish, a feat long thought to be impossible. The technique, reported today in Nature1, could help to reveal the molecular steps involved in sperm formation and might even lead to treatments for male infertility.
Biologists have been trying to make sperm outside the body for almost a century. Failure has often struck at the stage of meiosis, a type of cell division during which paired chromosomes swap DNA and the number of chromosomes per cell is halved. The result of this process is sperm cells ready to fuse with an egg.
An experimental gene therapy injected into the brains of patients with Parkinson’s disease improved tremor, stiffness, and other movement symptoms and was safe with few side effects over six months of follow-up, a study shows.
The small study represents the first successful clinical trial comparing a gene-based treatment to sham treatment in Parkinson’s or any neurologic disorder, says Michael Kaplitt, MD, PhD, who developed the gene therapy more than a decade ago. He hopes to market it if phase III trials confirm its effectiveness.
Kaplitt is vice president for research in the department of neurological surgery at Weill Cornell Medical College in New York City. He is a co-founder of the company Neurologix, which is developing the treatment and funded the study.
Although it won’t be obvious to UCSF Medical Center patients, behind the scenes a family of giant robots now counts and processes their medications. With a new automated hospital pharmacy, believed to be the nation’s most comprehensive, UCSF is using robotic technology and electronics to prepare and track medications with the goal of improving patient safety.
Not a single error has occurred in the 350,000 doses of medication prepared during the system’s recent phase in.
The robots tower over humans, both in size and ability to deliver medications accurately. Housed in a tightly secured, sterile environment, the automated system prepares oral and injectable medicines, including toxic chemotherapy drugs. In addition to providing a safer environment for pharmacy employees, the automation also frees UCSF pharmacists and nurses to focus more of their expertise on direct patient care.
With the flick of a precisely placed light switch, mice can be induced to cower in a corner in fear or bravely explore their environment. The study highlights the power of optogenetics technology—which allows neuroscientists to control genetically engineered neurons with light—to explore the functions of complex neural wiring and to control behavior.
In the study, Karl Deisseroth and collaborators at Stanford University identified a specific circuit in the amygdala, a part of the brain that is central to fear, aggression, and other basic emotions, that appears to regulate anxiety in rodents. They hope the findings, published today in the journal Nature, will shed light on the biological basis for human anxiety disorders and point toward new targets for treatment.
Women who drink a cup or more of coffee each day may be less likely to have a stroke, compared to women who drink less coffee, according to new research in the journal Stroke.
The new findings should not be taken to mean that everyone should start drinking coffee to lower their stroke risk, as the medical literature has been somewhat mixed regarding the effects of coffee on cardiovascular risk.
Of 34,670 women aged 49 to 83, women who drank more than a cup of coffee each day had a 22% to 25% lower risk for stroke than women who drank less coffee.
Women who reported drinking anywhere from one to five or more cups of coffee a day showed similar benefits in stroke reduction. Drinking more coffee did not reduce stroke risk any further, the study showed.
Eating fatty fish one or more times a week may reduce your risk for developing age-related macular degeneration, a leading cause of vision loss in people aged 60 and older. The new findings appear online in the Archives of Opthalmology.About 9 million Americans aged 40 and older show signs of age-related macular degeneration AMD and 7.3 million more people have an early form of this potentially vision-robbing disease.
AMD targets the part of the eye that allows you to focus in on details the macula. The disease destroys the sharp, central vision needed to see objects clearly, read, and drive. In some people the disease progresses slowly; in others, a faster progression can lead to vision loss in both eyes.
Women in the new study who got the highest amounts of docosahexaenoic acid DHA, an omega-3 fatty acid found in fish, were 38% less likely to develop AMD than women who got the least DHA. Similar findings were seen regarding the highest consumption levels of eicosapentaenoic acid EPA, another omega-3 found in fatty fish.
Just about every week, it seems, a new study warns of another potential health risk linked to soft drinks.
The most recent headlines have raised concerns that diet sodas boost stroke risk. Diet and regular sodas have both been linked to obesity, kidney damage, and certain cancers. Regular soft drinks have been linked to elevated blood pressure.
Several hundred soda studies have been published over the last two decades, but most of the ones done in humans (as opposed to mice or rats) relied on people’s memories of what they drank.
Observational studies like these can point to possible concerns, but they can’t prove that sodas do, or don’t, pose a health risk.
If you drink sodas — especially if you drink a lot of them — what are you to make of all the headlines? Do you dismiss them, as the beverage industry does, as bad science and media hype? Or is it time to put the can down and take a hard look at what you’re drinking?
Researchers in Australia have identified four molecular characteristics, or biomarkers, of asthma and chronic obstructive pulmonary disease (COPD), which they say could lead to better ways to diagnose the respiratory conditions.
The biomarkers were discovered using a relatively new field of science known as proteomics, which is the study of the proteins that are involved in the make-up of an organism.
During about 30 percent of all heart attacks, the patient experiences no symptoms. However, unmistakable signs of the attack remain in the bloodstream for days. MIT researchers, working with Massachusetts General Hospital’s Cardiovascular Research Center, have now designed a tiny implant that can detect those signs, which could help doctors more rapidly determine whether a patient has had a heart attack.
In a study of mice, the team showed that the new implants can detect three proteins whose levels spike after a heart attack. Such devices could be used to monitor patients who are at high risk of heart attack, allowing doctors to respond more quickly if an attack occurs, preventing more severe heart disease from developing.
When designing new cancer drugs, biologists often target specific gene mutations found only in cancer cells, or in a subset of cancer cells. A team of MIT biologists is now taking a slightly different approach, targeting a trait shared by nearly all cancer cells — they have too many chromosomes.
MIT biology professor Angelika Amon has been studying this peculiarity, known as aneuploidy, for several years. In developing fetuses, aneuploidy causes death or birth defects. However, in cancer cells, aneuploidy appears to confer a survival advantage.
Filling up on fiber — particularly fiber from whole grains — may reduce your risk of dying from heart disease, infections, and respiratory diseases, says a new study published online in the Archives of Internal Medicine.
Men and women who ate the most dietary fiber were 22% less likely to die from any cause when compared to study participants who ate the least amount of fiber. The protective effect came mainly from cereal fiber in grains, not other sources of fiber such as fruits and vegetables.
Adult cells that have been reprogrammed into stem cells harbor a number of genetic mutations, some of which appear in genes that have been linked to cancer. While scientists don’t yet know how this might affect the use of the cells in medicine, they say the findings show that the cells need to be studied much more extensively.
“As we think about using [these] cells for therapy, we will want to consider what kinds of screening tests we want to do,” says Lawrence Goldstein, a professor of molecular biology at the University of California, San Diego. One of the major concerns about stem-cell-based therapies has been whether they carry a risk of cancer; both stem cells and cancer cells are distinguished by their ability to continually divide.
Memories fade with time, often to the annoyance of those who can’t recall important details. But scientists have now found a way to boost the recall of memories even after they’ve started to fade. Unfortunately, the method involves injecting an engineered virus directly into the brain, so those of us who are bad with names may want to wait a bit for the technique to be refined.
The work was done in rats, and the memories in question are associations between a specific taste—saccharine, for example—and an unpleasant stimulus, caused by injection of a nausea-inducing drug (the approach is called “conditioned taste aversion”). Unless the unpleasant association is reinforced, the memories will slowly fade with time, although the aversion doesn’t disappear entirely during the two-week period that the authors were
New research lends support to the idea that exposure to a wide range of microbes explains why farm kids have lower asthma rates than city kids.
School-aged children in the studies who lived on farms were about 30% to 50% less likely to have asthma than non-farm children who lived nearby.
Farm-dwelling children were also exposed to more bacteria and fungi than the other children.
The studies, which appear in the Feb. 24 edition of the New England Journal of Medicine, suggest a role for the so-called hygiene hypothesis in the development of childhood asthma.
According to the hypothesis, exposure to bacteria and fungi from environmental sources like dirt and animal hair early in life protects against asthma and allergies by helping the immune system develop normally.
It is theorized that increasingly clean environments may at least partially explain why asthma rates have doubled in developed nations in just the last three decades.
When your brain encounters sensory stimuli, such as the scent of your morning coffee or the sound of a honking car, that input gets shuttled to the appropriate brain region for analysis. The coffee aroma goes to the olfactory cortex, while sounds are processed in the auditory cortex.
That division of labor suggests that the brain’s structure follows a predetermined, genetic blueprint. However, evidence is mounting that brain regions can take over functions they were not genetically destined to perform. In a landmark 1996 study of people blinded early in life, neuroscientists showed that the visual cortex could participate in a nonvisual function — reading Braille.
High-resolution images from a laser-based tool developed at Duke University could help doctors better diagnose melanoma, the deadliest form of skin cancer.
The improved diagnoses could potentially save thousands of lives and millions of dollars in unnecessary healthcare costs each year.
The tool probes skin cells using two lasers to pump small amounts of energy, less than that of a laser pointer, into a suspicious mole. Scientists analyze the way the energy redistributes in the skin cells to pinpoint the microscopic locations of different skin pigments.
For the first time, scientists have the ability to identify substantial chemical differences between cancerous and healthy skin tissues, said Thomas Matthews, a Duke graduate student who helped develop the new two-laser microscopy technique.
The Duke team imaged 42 skin slices with the new tool. The images show that melanomas tend to have more eumelanin, a kind of skin pigment, than healthy tissue. Using the amount of eumelanin as a diagnostic criterion, the team used the tool to correctly identify all eleven melanoma samples in the study. The results appear in the Feb. 23 Science Translational Medicine.
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In the brains of people blind from birth, structures used in sight are still put to work — but for a very different purpose. Rather than processing visual information, they appear to handle language.
Linguistic processing is a task utterly unrelated to sight, yet the visual cortex performs it well.
“It suggests a kind of plasticity that’s even broader than the kinds observed before,” said Marina Bedny, a cognitive neuroscientist at the Massachusetts Institute of Technology. “It’s a really drastic change. It suggests there isn’t a predetermined function an area can serve. It can take a wide range of possible functions.”
In a study published Tuesday in the Proceedings of the National Academy of Sciences, Bedny’s team monitored the brain activity of five congenitally blind individuals engaged in language-intensive tasks.
Immense neurological plasticity was suggested by research conducted in the late 1990s on “rewired” ferrets — after their optical nerves were severed and rerouted into their auditory cortices, they could still see — but such studies, already ethically troubling in animals, would be unconscionable in humans
A handheld device that detects proteins produced by tumor cells could give doctors a fast, accurate way to diagnose and monitor cancer. Tumor-marker testing usually requires pea-size tissue samples and can take days in a laboratory to yield results. The new detector, by contrast, requires a tiny speck of tissue, takes less than an hour to process samples, and could be used in a doctor’s office instead of a hospital.
The device, which was developed by researchers at Harvard Medical School, attaches to a smartphone, providing a user-friendly interface for doctors to view results. In tests on patient tissue samples, the researchers accurately detected cancer 96 percent of the time. They reported the results last week in the journal Science Translational Medicine.
Photo: C. Min/H. Lee/R. Weissleder/Harvard Medical School