News 18 juni 2009
Scientists Find Faster, Cheaper Way
to Identify Cancer-Causing Genes
Researchers at the University of Virginia Health System have found a new way to study how
genes function in living organisms, and their approach could substantially cut the time
and costs that drug makers spend in searching for potential targets for new cancer
therapies. “A big problem in biology is that there are many thousands of genes.
Testing the function of any one of them in a living organism, such as a mouse, has
traditionally been slow and very expensive,” notes Ian Macara, PhD, professor of
microbiology at UVA’s School of Medicine and co-author of a study published in the
June 15 issue of Genes & Development. “The new technology is hundreds of times
cheaper and many times faster than traditional approaches. While we used it to study the
function of a specific breast-developing gene, our method can be replicated in screening
for genes that can suppress tumors or cause cancer.” In Genes & Development, UVA
researchers describe how they isolated mammary gland stem cells from mice and then
infected the cells with a virus that enabled the scientists to manipulate a particular
gene and cause it to glow green. When transplanted in mice that had undergone
mastectomies, the altered stem cells regenerated entire new breasts within a few months.
Because the target gene glowed green, researchers could monitor its role in the
development of the new breast.
Fibromyalgia Patients Show
Decreases in Gray Matter Intensity
Previous studies have shown that fibromyalgia is associated with reductions in gray matter
in parts of the brain, but the exact cause is not known. Using sophisticated brain imaging
techniques, researchers from Louisiana State University, writing in The Journal of Pain,
found that alterations in levels of the neurotransmitter dopamine might be responsible for
gray matter reductions. For the study, magnetic imaging resonance data from 30 female
fibromyalgia patients were compared with 20 healthy women of the same age. The primary
objective of the study was to confirm original findings about reduced gray matter density
in a larger sample of fibromyalgia patients. They explored whether there is a correlation
between dopamine metabolic activity and variations in the density of gray matter in
specific brain regions. Results showed there were significant gray matter reductions in
the fibromyalgia patients, which supports previous research. In addition, the fibromyalgia
patients showed a strong correlation of dopamine metabolism levels and gray matter density
in parts of the brain in which dopamine controls neurological activity. The authors
concluded that the connection between dopamine levels and gray matter density provide
novel insights to a possible mechanism that explains some of the abnormal brain morphology
associated with fibromyalgia.
Study Pinpoints Links of Depression
with Chronic Pain
It is well known that chronic pain and clinical depression go together, but a study in The
Journal of Pain, published by the American Pain Society, shows that the connection between
pain and depression is strongest in middle-age women and African Americans.
Discovery of the cell's water gate
may lead to new cancer drugs
The flow of water into and out from the cell may play a crucial role in several types of
cancer. Scientists at the University of Gothenburg have now found the gate that regulates
the flow of water into yeast cells. The discovery, which will be published in the journal
PLoS Biology, raises hopes of developing a drug that inhibits the spread and growth of
tumours. All living organisms must be able to regulate the flow of water into and out from
cells, in order to maintain cell form and size. This regulation is carried out by special
proteins known as "aquaporins". These act as water channels and control the flow
of water into and out from the cell.
Crustacean shell with polyester
creates mixed-fiber material for nerve repair
In the clothing industry it's common to mix natural and synthetic fibers. Take cotton and
add polyester to make clothing that's soft, breathable and wrinkle free. Now researchers
at the University of Washington are using the same principle for biomedical applications.
Mixing chitosan, found in the shells of crabs and shrimp, with an industrial polyester
creates a promising new material for the tiny tubes that support repair of a severed
nerve, and could serve other medical uses. The hybrid fiber combines the biologically
favorable qualities of the natural material with the mechanical strength of the synthetic
polymer. "A nerve guide requires very strict conditions. It needs to be
biocompatible, stable in solution, resistant to collapse and also pliable, so that
surgeons can suture it to the nerve," said Miqin Zhang, a UW professor of material
science and engineering and lead author of a paper now available online in the journal
Advanced Materials. "This turns out to be very difficult."After an injury that
severs a peripheral nerve, such as one in a finger, nerve endings continue to grow. But to
regain control of the nerve surgeons must join the two fragments. For large gaps surgeons
used to attempt a more difficult nerve graft. Current surgical practice is to attach tiny
tubes, called nerve guides, that channel the two fragments toward each other. Today's
commercial nerve guides are made from collagen, a structural protein derived from animal
cells. But collagen is expensive, the protein tends to trigger an immune response and the
material is weak in wet environments, such as those inside the body. The strength of the
nerve guide is important for budding nerve cells.
Powerful Nutrient Cocktail Can Put
Kids with Crohn's into Remission
Treating children with inflammatory bowel disease (IBD) usually involves the same
steroids-based medication prescribed to adults. But such treatments can have negative side
effects for kids and teens dealing with IBD. Dr. Raanan Shamir of Tel Aviv University's
Sackler School of Medicine and Schneider Children's Medical Centre shows that there is
another path to treating IBD in children: a nutritional formula that was first developed
for astronauts. This supplement puts 60-70% of children with Crohn's disease, a common IBD
disorder, into remission — a success rate similar to that of traditional
steroid-based drugs, but without side effects like malnutrition and growth retardation.
Study finds reproductive health
effects from low doses of bisphenol-A
New research from North Carolina State University and the National Institute of
Environmental Health Sciences (NIEHS) shows significant reproductive health effects in
rats that have been exposed to bisphenol-A (BPA) at levels equivalent to or below the dose
that has been thought not to produce any adverse effects. BPA is a chemical found in baby
bottles, water bottles, canned foods and an array of other consumer products. The
potential health effects of BPA are currently the subjects of intense debate. The study
found that female rats exposed to a BPA dose of 50 micrograms per kilogram of body weight
(µg /kg) in their first four days of life experienced early onset of puberty. Female rats
exposed to 50 milligrams per kilogram of body weight (mg/kg) during their first four days
of life developed significant ovarian malformations and premature loss of their estrus
cycle. "The 50 mg/kg level is important," says lead researcher Dr. Heather
Patisaul, "because it is equivalent to the U.S. Environmental Protection Agency's
'Lowest Observable Adverse Effect Level' for BPA. So, by definition, we should not have
seen significant effects at or below this level, but we did." Patisaul, an assistant
professor of biology at NC State, explains that the 50 µg /kg level is also significant
because it is EPA's listed reference dose for BPA – meaning it is the level of BPA
that EPA says a person can be exposed to on a daily basis without expecting any adverse
effects after a lifetime of exposure. Patisaul stresses that the research was done on
rats, making it difficult to determine its applicability to humans, but notes that
"this adds to a growing body of evidence that exposure to low doses of BPA during
development can impact female reproductive health." The female rats in the study were
exposed during the first four days of life because that is a sensitive developmental
window for the rats, similar to a sensitive developmental stage that takes place for
humans when they are still in the womb. While exposure to the lowest dose, 50 µg /kg,
resulted in early onset of puberty in the rats, exposure to higher dose had more
complicated results.
Brain detects happiness more
quickly than sadness
People make value judgements about others based on their facial expressions. A new study,
carried out be Spanish and Brazilian researchers, shows that – after looking at a
face for only 100 milliseconds – we can detect expressions of happiness and surprise
faster than those of sadness or fear. Our brains get a first impression of people's
overriding social signals after seeing their faces for only 100 milliseconds (0.1
seconds). Whether this impression is correct, however, is another question. Now an
international group of experts has carried out an in-depth study into how we process
emotional expressions, looking at the pattern of cerebral asymmetry in the perception of
positive and negative facial signals. The researchers worked with 80 psychology students
(65 women and 15 men) to analyze the differences between their cerebral hemispheres using
the "divided visual field" technique, which is based on the anatomical
properties of the visual system. "What is new about this study is that working in
this way ensures that the information is focused on one cerebral hemisphere or the
other", J. Antonio Aznar-Casanova, one of the authors of the study and a researcher
at the University of Barcelona (UB), tells SINC.
Researchers make progress toward
early identification of muscular dystrophy
The saying "Knowing is half the battle" is never more true than when discussing
early treatment of disease. Muscular dystrophy is one such disease where patients can
benefit from early treatment. Now, new research is moving doctors and scientists closer to
disease diagnosis in advance of patient symptoms. A team of University of Birmingham
researchers used mice as model animals to study the key proteins involved in two types of
muscular dystrophy (MD): the most severe MD form, Duchenne Muscular Dystrophy (DMD), and a
more mild form, Limb Girdle MD (LGMD-1c). As described in their new report published in
Disease Models & Mechanisms (DMM), dmm.biologists.org, the researchers found disrupted
stem cell function and delays of skeletal muscle formation in embryos of MD-like mice.
.The severity of these embryonic abnormalities closely corresponded to the severity of
symptoms seen in DMD or Limb Girdle MD. This study demonstrates that there are prenatal
signs for muscular dystrophy, and suggests that both types of MD might be detected in
utero or shortly after birth. This work has the potential to create a better quality of
life for DMD children. It is now clear that early treatment significantly improves life
expectancy and quality of life for DMD children. However, diagnosis is often delayed until
the disease is well under way, around ages 3-5 years, and treatment thus often begins
between ages 4-8 years, when the disease is already established. This new research
indicates that understanding these MD-associated proteins can lead to earlier diagnoses
and treatment for DMD/LGMD patients. This in turn leads to longer life and enhanced
quality of life for individuals affected by these diseases.
Statins don't lower risk of
pneumonia in elderly
Taking popular cholesterol-lowering statin drugs, such as Lipitor® (atorvastatin), does
not lower the risk of pneumonia. That's the new finding from a study of more than 3,000
Group Health patients published online on June 16 in advance of the British Medical
Journal's June 20 print issue. "Prior research based on automated claims data had
raised some hope—and maybe some hype—for statins as a way to prevent and treat
infections including pneumonia," said Sascha Dublin, MD, PhD, a physician at Group
Health and assistant investigator at Group Health Center for Health Studies. "But
when we used medical records to get more detailed information about patients, our findings
didn't support that approach." In fact, Dublin's population-based case-control study
found that pneumonia risk was, if anything, slightly higher (26%) in people using a statin
than in those not using any; and this extra risk was even higher (61%) for pneumonia
severe enough to require being hospitalized. "As a doctor, I'm a fan of statins for
what they've been proven to do: lowering cholesterol and risk of heart disease and stroke
in people who've had either disease or are at risk for them," said Dublin. Statins
are HMG coenzyme A reductase inhibitors, which also include Zocor® (simvastatin) and
Mevacor® (lovastatin). This class of medications lessens inflammation, which plays a role
in infections. "But now we and some others have found that statins may have gotten
some unearned credit for health benefits that they don't actually have, including
preventing pneumonia," Dublin said.Suggestions from prior research had led to calls
for expensive randomized controlled trials of statins to prevent or treat infection.
"But our study indicates that such trials would be an ill-advised use of limited
research funds at this time," she added.
Putting a name to a face may be key
to brain's facial expertise
Our tendency to see people and faces as individuals may explain why we are such experts at
recognizing them, new research indicates. This approach can be learned and applied to
other objects as well."This new research adds to the evidence that the brain
processes faces differently because of our expertise with them. It also tells us what it
is about our experience with faces that leads us to treat them holistically," Isabel
Gauthier, associate professor of psychology at Vanderbilt University and one of the
study's co-authors, said. "This knowledge may be useful in the development of
training protocols for individuals with difficulties in face perception, such as
individuals with autism spectrum disorders." The research is currently in press at
Psychological Science. Gauthier's co-authors are Alan Wong, who completed the study as his
doctoral thesis in psychology at Vanderbilt, and Thomas Palmeri, associate professor of
psychology. Wong is now an assistant professor at Chinese University of Hong Kong.
"Our findings suggest that facial expertise does not just develop with any type of
experience," Wong said. "Learning to recognize a set of objects as individuals
may work, but categorizing them at a more general level, or learning to manipulate them,
would not. We develop different types of expertise in recognizing different objects not
just due to their unique appearance, but also because of the types of experience we have
had with them."For decades, scientists have debated whether we are better able to
recognize faces because we have evolved a brain system dedicated to this task or because
we have extensive practice recognizing faces. Researchers agree that we recognize faces
holistically, which is not how we generally recognize other objects. For example, we find
it almost impossible to attend to only one part of a face and ignore the rest, while we
might recognize a car by its grill, taillights or branding.
Another McGill/JGH breakthrough
opens door to early Alzheimer's diagnosis
A new diagnostic technique which may greatly simplify the detection of Alzheimer's disease
has been discovered by researchers at McGill University and the affiliated Lady Davis
Institute for Medical Research at Montreal's Jewish General Hospital (JGH). Their results
were published June 8 in the Journal of Alzheimer's Disease. There is currently no
accepted blood test for Alzheimer's, and the diagnosis is usually based on expensive and
labour-intensive neurological, neuropsychological and neuroimaging evaluations. Dr. Hyman
Schipper and colleagues at the Lady Davis Institute and McGill University utilized a new
minimally-invasive technique called near-infrared (NIR) biospectroscopy to identify
changes in the blood plasma of Alzheimer's patients, changes which can be detected very
early after onset, and possibly in pre-clinical stages of the disease. Biospectroscopy is
the medical form of spectroscopy, the science of detecting the composition of substances
using light or other forms of energy. In NIR spectroscopy, different substances emit or
reflect light at specific, detectable wavelengths.
Novel light-sensitive compounds
show promise for cancer therapy
Chemists at the University of California, Santa Cruz, have developed novel compounds that
show promise for photodynamic cancer therapy, which uses light-activated drugs to kill
tumor cells. The new compounds, called dye-sensitized ruthenium nitrosyls, are absorbed by
cancer cells and respond to specific wavelengths of light by releasing nitric oxide, which
triggers cell death. "For cancer treatment, you want localized delivery of a very
high concentration of nitric oxide. We've designed these molecules to do just that,"
said Pradip Mascharak, professor of chemistry and biochemistry at UCSC. Nitric oxide is a
simple molecule with a wide range of biological effects. Long known for its role in
regulating blood pressure, it has attracted the attention of cancer researchers in recent
years. According to Mascharak, one advantage of nitric oxide for cancer treatment is that
it induces an orderly type of cell death known as apoptosis. Also known as
"programmed cell death," apoptosis does not lead to the inflammation, pain, and
swelling normally associated with damage to cells and tissues in the body. The drugs
currently used in photodynamic therapy, called photosensitizers, produce a highly reactive
form of oxygen when activated by light. The reactive oxygen kills cells in a way that
tends to cause local swelling and inflammation. Mascharak and graduate student Michael
Rose have synthesized several different ruthenium nitrosyls in their lab. They described
these compounds in detail in a recent paper published in Inorganic Chemistry (published
online May 29, 2009). In another paper published last year in the Journal of the American
Chemical Society, the researchers reported that the compounds were effective against
breast cancer cells in laboratory experiments. "We know it works in cancer cells, so
now we're very confident about taking it to the next level," Mascharak said.
"The idea for cancer therapy would be to embed the compounds in a matrix that you can
place in the treatment site, then shine light on it to produce a high concentration of
nitric oxide."
Trans fats hinder multiple steps in
blood flow regulation pathways
Partially hydrogenated vegetable oils in processed foods contain trans fatty acids that
interfere with the regulation of blood flow. A new report reveals a new way in which these
"trans fats" gum up the cellular machinery that keeps blood moving through
arteries and veins. In the August 2009 issue of the international journal Atherosclerosis,
University of Illinois emeritus veterinary biosciences professor Fred Kummerow reports for
the first time that trans fats interfere with more than one key enzyme in the regulation
of blood flow. Kummerow begins by describing the two main causes of heart disease –
sudden blood clots in the coronary arteries, and atherosclerosis, the buildup of plaque in
the arteries to the point where it interferes with blood flow. "The arteries of
someone who dies from atherosclerosis look like old scrub boards as a result of the
formation of plaques," Kummerow said. "They look corrugated, and this plaque
buildup continues to the point where it will stop blood flow." Trans fats contribute
to both of these causes of heart disease, Kummerow said. Trans fats are made through
hydrogenation, which involves bubbling hydrogen through hot vegetable oil, changing the
arrangement of double bonds in the essential fatty acids in the oil and
"saturating" the "unsaturated" carbon chain with hydrogen. Because
double bonds are rigid, altering them can straighten or twist fat molecules into new
configurations that give the fats their special qualities, such as the lower melting point
of margarine that makes it creamy at room temperature. Kummerow, 94, has spent nearly six
decades studying lipid biochemistry, and is a long-time advocate for a ban on trans fats
in food.
UCF researcher's nanoparticles
could someday lead to end of chemotherapy
Nanoparticles specially engineered by University of Central Florida Assistant Professor J.
Manuel Perez and his colleagues could someday target and destroy tumors, sparing patients
from toxic, whole-body chemotherapies. Perez and his team used a drug called Taxol for
their cell culture studies, recently published in the journal Small, because it is one of
the most widely used chemotherapeutic drugs. Taxol normally causes many negative side
effects because it travels throughout the body and damages healthy tissue as well as
cancer cells. The Taxol-carrying nanoparticles engineered in Perez's laboratory are
modified so they carry the drug only to the cancer cells, allowing targeted cancer
treatment without harming healthy cells. This is achieved by attaching a vitamin (folic
acid) derivative that cancer cells like to consume in high amounts. Because the
nanoparticles also carry a fluorescent dye and an iron oxide magnetic core, their
locations within the cells and the body can be seen by optical imaging and magnetic
resonance imaging (MRI). That allows a physician to see how the tumor is responding to the
treatment. The nanoparticles also can be engineered without the drug and used as imaging
(contrast) agents for cancer. If there is no cancer, the biodegradable nanoparticles will
not bind to the tissue and will be eliminated by the liver. The iron oxide core will be
utilized as regular iron in the body.
Study finds autistics better at
problem-solving
Autistics are up to 40 percent faster at problem-solving than non-autistics, according to
a new Université de Montréal and Harvard University study published in the journal Human
Brain Mapping. As part of the investigation, participants were asked to complete patterns
in the Raven's Standard Progressive Matrices (RSPM) – test that measures
hypothesis-testing, problem-solving and learning skills. "While both groups performed
RSPM test with equal accuracy, the autistic group responded more quickly and appeared to
use perceptual regions of the brain to accelerate problem-solving," says lead author
Isabelle Soulières, a post-doctoral fellow at Harvard University who completed the
experiment at the Université de Montréal. "Some critics agued that autistics would
be unable to complete the RSPM because of its complexity, yet our study shows autistics
complete it as efficiently and have a more highly developed perception than
non-autistics." Fifteen autistics and 18 non-autistics were recruited for the study.
Participants were 14 to 36 years old and matched according to their preliminary results on
the Wechsler Adult Intelligence Scale. All subjects underwent magnetic resonance imaging
to explore their neural activity during RSPM problem-solving. While autism is a common
neurodevelopmental disability characterized by profound differences in information
processing and analysis, this study showed that autistics have efficient reasoning
abilities that build on their perceptual strengths. "This study builds on our
previous findings and should help educators capitalize on the intellectual abilities of
autistics," says senior researcher Laurent Mottron, the new Marcel & Rolande
Gosselin Research Chair in Autism Cognitive Neuroscience of the Université de Montréal
and psychiatry professor. "The limits of autistics should constantly be pushed and
their educational materials should never be simplified."
Research proves tai chi benefits
for arthritis
A new study by The George Institute for International Health has found Tai Chi to have
positive health benefits for musculoskeletal pain. The results of the first comprehensive
analysis of Tai Chi suggest that it produces positive effects for improving pain and
disability among arthritis sufferers. The researchers are now embarking on a new trial to
establish if similar benefits can be seen among people with chronic low back pain.
"This is the first robust evidence to support the beneficial effects of Tai Chi. Our
study proves that Tai Chi relieves pain and disability among people with arthritis and
shows a positive trend towards effects for overall physical health. We now want to see if
these benefits are the same for people suffering from low back pain", said author Dr
Chris Maher at The George Institute. Musculoskeletal pain, such as that experienced by
people with arthritis, places a severe burden on the patient and community and is
recognised as an international health priority. Arthritis is the major cause of disability
and chronic pain in Australia, with 3.85million Australians affected. Low back pain is the
most prevalent and costly musculoskeletal condition in Australia, estimated to cost up to
$1billion per annum with indirect costs exceeding $8billion.
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