News 31 juli 2009
Research shows rates of severe
childhood obesity have tripled
Rates of severe childhood obesity have tripled in the last 25 years, putting many children
at risk for diabetes and heart disease, according to a report in Academic Pediatrics by an
obesity expert at Brenner Children's Hospital, part of Wake Forest University Baptist
Medical Center. "Children are not only becoming obese, but becoming severely obese,
which impacts their overall health," said Joseph Skelton, M.D., lead author and
director of the Brenner FIT (Families in Training) Program. "These findings reinforce
the fact that medically-based programs to treat obesity are needed throughout the United
States and insurance companies should be encouraged to cover this care." The research
was published on-line and will appear in the September print edition. Skelton and
colleagues compared data from the National Health and Nutrition Examination Survey
(NHANES). They looked at the prevalence of obesity and severe obesity in a study
population of 12,384 children, representing approximately 71 million U.S. children ages 2
to 19 years. Severe childhood obesity is a new classification for children and describes
those with a body mass index (BMI) that is equal to or greater than the 99th percentile
for age and gender. For example, a 10-year-old child with a BMI of 24 would be considered
severely obese, Skelton said, whereas in an adult, that is considered a normal BMI. An
expert committee convened by the American Medical Association, the Centers for Disease
Control and the Department of Health and Human Services proposed the new classification in
2007. The research by Skelton and colleagues is the first of its kind to use the new
classification and detail the severity of the problem. They found that the prevalence of
severe obesity tripled (from 0.8 percent to 3.8 percent) in the period from 1976-80 to
1999-2004. Based on the data, there are 2.7 million children in the U.S. who are
considered severely obese. Increases in severe obesity were highest among blacks and
Mexican-Americans and among those below the poverty level. For example, the percentage of
Mexican-American children in the severely obese category was 0.9 percent in 1976-80 and
5.2 percent in 1999-2004.
NIST scientists study how to stack
the deck for organic solar power
A new class of economically viable solar power cells—cheap, flexible and easy to
make—has come a step closer to reality as a result of recent work* at the National
Institute of Standards and Technology (NIST), where scientists have deepened their
understanding of the complex organic films at the heart of the devices. Organic
photovoltaics, which rely on organic molecules to capture sunlight and convert it into
electricity, are a hot research area because in principle they have significant advantages
over traditional rigid silicon cells. Organic photovoltaics start out as a kind of ink
that can be applied to flexible surfaces to create solar cell modules that can be spread
over large areas as easily as unrolling a carpet. They'd be much cheaper to make and
easier to adapt to a wide variety of power applications, but their market share will be
limited until the technology improves. Even the best organic photovoltaics convert less
than 6 percent of light into electricity and last only a few thousand hours. "The
industry believes that if these cells can exceed 10 percent efficiency and 10,000 hours of
life, technology adoption will really accelerate," says NIST's David Germack.
"But to improve them, there is critical need to identify what's happening in the
material, and at this point, we're only at the beginning." The NIST team has advanced
that understanding with their latest effort, which provides a powerful new measurement
strategy for organic photovoltaics that reveals ways to control how they form. In the most
common class of organic photovoltaics, the "ink" is a blend of a polymer that
absorbs sunlight, enabling it to give up its electrons, and ball-shaped carbon molecules
called fullerenes that collect electrons. When the ink is applied to a surface, the blend
hardens into a film that contains a haphazard network of polymers intermixed with
fullerene channels. In conventional devices, the polymer network should ideally all reach
the bottom of the film while the fullerene channels should ideally all reach the top, so
that electricity can flow in the correct direction out of the device. However, if barriers
of fullerenes form between the polymers and the bottom edge of the film, the cell's
efficiency will be reduced.
Little-known protein found to be
key player
- Italian and U.S. biologists this week report that a little-understood protein previously
implicated in a rare genetic disorder plays an unexpected and critical role in building
and maintaining healthy cells. Even more surprising, their report in the journal Nature
shows that the protein, called "atlastin," does its work by fusing intracellular
membranes in a previously undocumented way. "If you'd asked me a year ago whether
this was possible, I would have said, 'No,'" said study co-author James McNew,
associate professor of biochemistry and cell biology at Rice University. "In fact,
that's exactly what I told (co-author) Andrea Daga when we first spoke about the idea a
year ago." McNew has spent the past 15 years studying SNARE proteins, a specialized
family of proteins that carries out membrane fusion. It's a vital process that happens
thousands of times a second in every cell of our bodies. "It is fitting that the
discovery of a new protein capable of fusing membranes comes 10 years after the
demonstration that SNAREs can fuse lipid bilayers," said Daga, a researcher at the
Eugenio Medea Scientific Institute in Conegliano, Italy. In the new study, Daga's and
McNew's research teams used fruit flies to study how atlastin functions. The atlastin in
fruit flies is very similar to the human version of the protein and serves the same
function. "Prior to this, there were only two defined ways in which you could take
biological membranes and put them together in a specific way," said McNew, a faculty
investigator at Rice's BioScience Resesarch Collaborative. "Atlastin is the third,
and it's the only one that requires enzymatic activity, so it's distinctly
different." Using a range of tests on purified proteins, live fruit flies and cell
cultures, the Italian and U.S. teams examined the effect of both an overabundance and a
scarcity of atlastin on cell function and on fruit fly development. They also created
mutant versions of the protein to see how it functioned -- or failed to function -- when
some parts were disabled.
Diabetes gene raises odds of lower
birth weight
Pediatric researchers have found that a gene previously shown to be involved in the
development of type 2 diabetes also predisposes children to having a lower birth weight.
The finding sheds light on a possible genetic influence on how prenatal events may set the
stage for developing diabetes in later childhood or adulthood. Researchers from The
Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine
published the study July 10 in the online version of the journal Diabetes. "It's a
bit unusual to find a gene linked to both prenatal events and to a disease that occurs
later in life," said study leader Struan F.A. Grant, Ph.D., a researcher at the
Center for Applied Genomics of The Children's Hospital of Philadelphia. "This gene
variant carries a double whammy, in raising the risk of both lower birth weight and the
development of type 2 diabetes in later life." Type 2 diabetes occurs either when the
pancreas produces too little insulin or when the body cannot efficiently use the insulin
that is produced. Formerly called adult-onset diabetes and still most common in adults,
type 2 diabetes has been increasing sharply among children.
Freshly crushed garlic better for
the heart than processed
A new study reports what scientists term the first scientific evidence that freshly
crushed garlic has more potent heart-healthy effects than dried garlic. Scheduled for the
Aug. 12 issue of the Journal of Agricultural and Food Chemistry, it also challenges the
widespread belief that most of garlic's benefits are due to its rich array of
antioxidants. Instead, garlic's heart-healthy effects seem to result mainly from hydrogen
sulfide, a chemical signaling substance that forms after garlic is cut or crushed and
relaxes blood vessels when eaten. In the study, Dipak K. Das and colleagues point out that
raw, crushed garlic generates hydrogen sulfide through a chemical reaction. Although best
known as the stuff that gives rotten eggs their distinctive odor, hydrogen sulfide also
acts as a chemical messenger in the body, relaxing blood vessels and allowing more blood
to pass through. Processed and cooked garlic, however, loses its ability to generate
hydrogen sulfide. The scientists gave freshly crushed garlic and processed garlic to two
groups of lab rats, and then studied how well the animals' hearts recovered from simulated
heart attacks. "Both crushed and processed garlic reduced damage from lack of oxygen,
but the fresh garlic group had a significantly greater effect on restoring good blood flow
in the aorta and increased pressure in the left ventricle of the heart," Das said.
Experimental treatment halts
hypoxic-ischemic brain injury in newborns
Inhibiting an enzyme in the brains of newborns suffering from oxygen and blood flow
deprivation stops a type of brain damage that is a leading cause of cerebral palsy, mental
retardation and death, according to researchers at Cincinnati Children's Hospital Medical
Center. Reporting their results in the Journal of Neuroscience, the scientists show
blocking the brain enzyme, tissue-type plasminogen activator (tPA), prevents progressive
brain damage triggered by the lack of oxygen and blood supply. The experimental
pre-clinical treatment involved putting a naturally occurring substance called plasminogen
activator inhibitor-1 (PAI-1) into the brains of newborn rats, said Chia-Yi Kuan, M.D.
PhD, senior investigator on the study and a researcher in the divisions of Developmental
Biology and Neurology at Cincinnati Children's. Besides demonstrating the brain's
plasminogen activator system plays a pivotal role in neonatal cerebral hypoxic-ischemic
brain injury, Dr. Kuan said the study also shows this system may be a promising
therapeutic target in infants suffering hypoxic-ischemic encephalopathy (HIE).
Identification of a treatment target is a vital step to finding better ways to treat
newborns with HIE. "Not only is hypoxic-ischemic encephalopathy an important cause of
perinatal mortality and permanent neurological morbidities, but there are no specific
medications against HIE in current medical practice," explained Ton J. DeGrauw, M.D.,
Ph.D., director of Neurology at Cincinnati Children's. "This is why the findings of
this study may have important clinical implications because, in a rodent model of HIE,
they that show inhibiting plasminogen activators in functional areas of the brain is
powerful strategy for brain protection." Earlier studies have pointed to the role
certain brain proteases, or enzymes, play in adult brain injury following stroke, but very
little has been known about what these enzymes do in neonatal cerebral hypoxic-ischemia,
according to the researchers. The enzyme in this case, tPA, normally breaks down proteins
and other molecules to eliminate blood clots.
Childhood adversities have a
predictive role in peptic ulcer
Helicobacter pylori, nonsteroidal anti-inflammatory drug use and smoking are the most
important risk factors for peptic ulcer. Alcohol intake may also play a role in the
development of gastric ulcers. Psychological stress may also have an impact on the onset
and course of ulcer disease. However, very little is known as to whether childhood
adversities involving financial problems, conflicts in the family, problems with alcohol,
and matters of personal security are associated with peptic ulcer. A research article to
be published on July 21,2009 in the World Journal of Gastroenterology addresses this
question. Dr. Markku Sumanen and his colleagues of the Health and Social Support Study
(HeSSup) investigated this subject in a nationwide sample of working-aged people in
Finland. The participants were asked whether or not a doctor had told them that they have
or have had a peptic ulcer. They were also asked to think about their childhood
adversities in terms of the following questions: 1) "Did your parents divorce?"
2) "Did your family have long-lasting financial difficulties?" 3) "Did
serious conflicts arise in your family?" 4) "Were you often afraid of some
member of your family?" 5) "Was someone in the family seriously or chronically
ill?" 6) "Did someone in the family have problems with alcohol?" The most
common childhood adversities to emerge were long-lasting financial difficulties in the
family, serious conflicts in the family and someone in the family having been seriously or
chronically ill. All adversities reported were more common among peptic ulcer patients
than among other respondents. Alcohol problems in the family and fear of some member of
the family were also more common among peptic ulcer patients than among other respondents.
With regard to parental divorce there was no statistically significant difference between
the two groups. Age- and sex-adjusted odds ratios (ORs) of childhood adversities for
peptic ulcer were statistically significant, indicating that participants with childhood
adversities had a higher proportional risk of developing peptic ulcer. Adjusting also for
smoking, heavy drinking, stress and current NSAID use had no further influence.
Long-lasting financial difficulties in the family had the greatest influence.According to
the findings there is reason to believe that stress factors during childhood maintain a
connection with the development of peptic ulcers. Childhood adversities are not
necessarily true risk factors for peptic ulcer, but may play a predictive role in the
development of the disease. A more comprehensive understanding of peptic ulcer patients is
worth aspiring to.
Humans "damaging the
oceans"
Mounting evidence that human activity is changing the world’s oceans in profound and
damaging ways is outlined in a new scientific discussion paper released today. Man-made
carbon emissions “are affecting marine biological processes from genes to ecosystems
over scales from rock pools to ocean basins, impacting ecosystem services and threatening
human food security,” the study by Professor Mike Kingsford of the ARC Centre of
Excellence for Coral Reef Studies and James Cook University and colleague Dr Andrew
Brierley of St Andrews University, Scotland, warns. Their review, published in the latest
issue of the journal Current Biology, says that rates of physical change in the oceans are
unprecedented in some cases, and change in ocean life is likely to be equally quick. These
include changes in the areas fish and other sea species can inhabit, invasions,
extinctions and major shifts in marine ecosystems. “In the past, the boundaries
between geological ages are marked by sudden losses of species. We may now be entering a
new age in which climate change and other human-caused factors such as fishing are the
major threats for the oceans and their life,” Andrew and Mike say. “Given how
essential the oceans are to how our entire planet functions it is vital that we intervene
before more tipping points are passed and the oceans go down the sort of spiral of decline
we have seen in the world’s tropical forests and rangelands, for example.”
Duke scientists create airway
spheres to study lung diseases
Using both animal and human cells, Duke University Medical Center scientists have
demonstrated that a single lung cell can become one of two very different types of airway
cells, which could lead to a better understanding of lung diseases. From this single
"basal" cell, a small, squat stem cell that divides to replenish the lung lining
layer, scientists created 3-D hollow spheres that were lined inside with both ciliary and
secretory cells. This 3-D model can be used to study dynamic processes underlying lung
diseases, including cancer, said Brigid Hogan, Ph.D., chair of the Duke Department of Cell
Biology and senior researcher of the study, which was published in PNAS Early Edition.
"Now that we have this 3-D model and information about the gene expression
'signature' of basal cells, we are in a strong position to see what happens when lung-cell
behavior goes awry," Hogan said. "We might, for example, be able to activate an
oncogene (a cancer-causing gene) or other factors to see how lung cancer might develop in
the airways. Amazingly, almost nothing is known about lung basal cells, which are so
important to health and make up nearly a third of the cells in the human
airways."Normally, basal stem cells maintain the airways by turning over slowly into
new ciliated cells and secretory cells. Ciliated cells resemble waving brooms that sweep
along particles and distribute secretions that are needed in the airways, and secretory
cells provide the antibacterial and lubricating secretions. These two types of cells are
neatly arranged in equal proportions in healthy lung airways. However, when lungs are
affected by maladies like cancer, chemical damage, cystic fibrosis or asthma, the balance
of these cells can be thrown off. By learning the role these basal cells play in
maintaining the airway tissue, the scientists were able to create an entirely new way to
study them.
Risų DTU develops magnetic Curie
valve that does not require power!
Christian Bahl is a Senior Scientist in the Fuel Cells and Solid State Chemistry Division
and works mainly with magnetic refrigeration. Magnetic refrigeration is an
energy-efficient cooling technique that could help save substantially on electricity
consumption in the long term. Through this, Christian Bahl has knowledge of the Curie
temperature of different substances. At the Curie temperature the material switches
between being magnetic and non magnetic. And precisely this property inspired the group to
create a shunt valve controlled by magnets. "If you imagine in your house at home
that you had one of our valves connected to the hot water circulation, running through
your radiators, then the valve would be able to lead the water through the radiators
again, provided the water is hot enough. The rest would go to reheating, "explains
Dan Eriksen who was employed on this project as a Development Engineer in July 2008. The
idea behind this new type of valve is that the liquid flows past a material with a certain
Curie temperature. When the liquid temperature falls below this temperature, the material
is attracted by a magnet outside the valve. If the temperature rises again, the material
is less attracted to the magnet, and is pushed back to its starting position by a spring.
This movement is used to activate the valve.
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