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Youth Tobacco Use: Downward Trend Is
Slowing
CDC Report Shows Current Cigarette Smoking by High School Students Is About
17%
By Bill Hendrick
Current tobacco use by middle and high school students has declined over the
past decade, but this trend has slowed in recent years and more work is
needed to combat the problem, the CDC says.
The CDC, reporting in its Morbidity and Mortality Weekly Report, says
comprehensive anti-tobacco programs need more funding and that the federal
government should enforce legislation that requires larger, graphic health
warnings on cigarette packages and in advertisements.
Further, broader tobacco-free policies, tobacco tax increases, and
advertisement restrictions would help further reduce both youth and adult
tobacco use, the report says.
The analysis was based on data from the National Youth Tobacco Survey, a
school-based study that collects information on tobacco use and related
behaviors. In this study, 22,679 young people participated; they were asked
to complete self-administered questionnaires each year from 2000 to 2009.
Besides cigarettes, youths were asked about use in the past month of cigars,
smokeless tobacco, pipes, small brown cigarettes wrapped in leaves, called
bidis, and clove cigarettes, or kreteks.
Current use was defined as use on at least one occasion in the past 30 days.
Experimentation was defined as ever having smoked a cigarette, even a puff
or two, but fewer than 100 cigarettes.
Among other things, the report says that, from 2000 to 2009:
Prevalence of current tobacco use reported by high school kids declined from
34.5% to 23.9%.
Prevalence of current cigarette use
dropped from 28% to 17.2%.
Experimentation with tobacco dropped
from 39.4% to 30.1%.
Prevalence of current tobacco use among
middle school students declined from 15.1% to 8.2%.
Prevalence of current cigarette use
among middle school kids dropped from 11% to 5.2%.
Among middle school kids,
experimentation with cigarettes declined from 29.8% to 15%.
The report notes that in 2009, some
8.2% of middle school students and 23.9% of those in high school reported
they used tobacco in some form.
Decreases from 2006 to 2009 were found only among middle school students for
current cigarette use in girls, dropping from 6.4% to 4.7%, and in
non-Hispanic whites, from 6.5% to 4.3% in the same years.
Among high school kids, declines were only in girls for current tobacco use,
dropping from 21.3% to 18.2%, and in current cigarette use, declining from
18.4% to 14.8%, and in non-Hispanic whites for use of bidis, from 2.6% to
1.7%.
"The general lack of significant change during the shorter period indicates
that the current rate of decline in tobacco use is relatively slow," the
researchers write.
Cigarette use and overall tobacco use among high school students both remain
above target levels, the CDC says.
"The findings from this report suggest further efforts are needed to counter
tobacco industry influences on youths," the CDC report says. "New Food and
Drug Administration regulations which prohibit the distribution of free
samples of smokeless tobacco to youths and prohibit tobacco brand name
sponsorship of any athletic, musical or other social or cultural events are
designed to help prevent tobacco use among youths."
Source:
Morbidity and Mortality Weekly Report, vol 59: pp 1063-1068.
Shared Decision-Making Is Better Than Solo
Study Shows Decisions Are Better When Two People of Equal Ability Work
Together
By Salynn Boyles
The old adage "two heads are better than one" really is true when both heads
are equally competent, new research finds.
In a study of shared decision-making, researchers from the University
College London (UCL) showed that two people of equal abilities solved
problems better when they worked together.
But when a competent person was paired with someone who wasn't so competent,
group and individual performance suffered.
The findings challenge the prevailing wisdom that groups rarely outperform
their best individual members, neuroscientist and researcher Chris Frith
tells.
The study appears in the Aug. 27 issue of Science.
"Our model showed that two equal heads are better than one for solving a
problem," he says. "But if the abilities of two people are very different,
they are probably better off working alone."
Joint Decisions Often Better
Bahador Bahrami, PhD, designed the study to test the "two heads" hypothesis
during his time as a UCL research fellow.
In one experiment, pairs of volunteers were briefly shown weak images on
separate computer screens and asked to recall when they saw an "oddball"
image with a slightly higher contrast than the others. When their answers
did not agree, the two volunteers discussed the matter and came up with a
joint decision.
Some volunteers were better at the task than others, but the joint decisions
proved to be more accurate more often than individual ones when two people
were paired who were equally good or equally bad at identifying the oddball
images.
Frith believes this may be because individuals tend to lose focus over time.
"Attention spans can wander in trials like this, but it is not likely to
happen to two people at the same time," he says.
In another experiment designed to explore the impact of incompetence on
shared decision- making, one person was shown clear images while that
person's partner was shown images that were much more difficult to see.
In this case, when the volunteer with the good information conferred with a
partner made incompetent by bad information, joint decisions tended to be
worse than individual ones made by the better performing partner.
Real-World Applications
The findings suggest people can work together most effectively when they
understand their individual competence level, Frith says.
"Joint decisions don't work when a member of the team is incompetent, but
doesn't know it," he says.
Bahrami acknowledges that such self-insight is uncommon in the real world.
"If you ask a group of people whether they are above-average drivers, most
of them will say yes," he says. "But this is logically wrong because
everyone can't be above average."
He does believe the findings have real-world applications, especially in
situations where competence is quantifiable.
"If you have a stock trader with a very good track record for picking stocks
and one with a poor record, the company may earn less money if they are
asked to work as a team," he says. "But two highly competent ones might make
more money for the company by working together."
Source:
Bahrami, B. Science, Aug. 27, 2010; vol 329: pp1081-1085.
Bahador Bahrami, PhD, research fellow, University College London, U.K.
Chris Frith, FRS, FBA, emeritus professor, Wellcome Trust Centre for
Neuroimaging, University College London.
Niels Bohr visiting professor, University of Aarhus, Denmark.
News release, Wellcome Trust Center for Neuroimaging, University College
London.
Egg Recall: FDA Finds Salmonella on Suspect Farms
Salmonella ID'd in Chicken Manure, Pullet Feed at Source of Recalled Eggs
By Daniel J. DeNoon
The farms implicated in the nationwide egg recall are indeed contaminated
with salmonella, FDA investigators find.
Fortunately, the FDA earlier this month pressured Wright County Egg and
Hillandale Farms -- two Iowa facilities that are part of the same company --
into voluntarily recalling over a half billion eggs. It's by far the largest
U.S. egg recall on record.
Now, for the first time, the FDA says its investigators have found
salmonella in four samples from the suspect facilities:
a sample from chicken manure
a manure sample found on a barn walkway
a sample from chicken feed made at a
pullet-raising facility that supplies hens to the two egg farms
a sample from a feed ingredient
FDA investigators are still testing
hundreds of other samples. In a few days, they will file a full report on
the extent of salmonella contamination at the facilities, Jeff Farrar, DVM,
PhD, MPH, FDA associate commissioner for food protection, said at a news
teleconference.
The salmonella found by investigators matches the DNA fingerprint of
salmonella that has sickened egg consumers in a nationwide outbreak, Sherri
McGarry, emergency coordinator for the FDA's food safety branch, said at the
news conference.
"Although it is a common salmonella strain, this finding in feed indicates
that Wright County Egg and Hillandale Farms are the likely sources of
contaminated eggs," McGarry said.
Meanwhile, the CDC continues to receive reports of people coming down with
salmonella food poisoning, Chris Braden, MD, acting director of the CDC's
center for food borne diseases, said at the news conference.
Braden said the CDC has now received 2,403 confirmed reports of salmonella
from May 1 through Aug. 25. Over the last five years, an average 933
salmonella illnesses are reported during this period. That means some 1,470
reported cases are due to the outbreak linked to eggs.
The CDC estimates that for every reported case, there are 30 to 38
unreported cases. That suggests that contaminated eggs have sickened some
44,100 to 55,860 Americans. Since reports take two to three weeks to reach
the CDC -- and since many contaminated eggs may still be in consumers'
refrigerators -- more illness reports are expected.
However, the CDC has not seen any new clusters of illness since the 26
previously reported. That suggests that there is no new source of
outbreak-associated salmonella.
Farrar said it's likely that new brand names will be added to the egg
recall. The FDA has an updated list of recalled eggs on its web site.
Sources:
Jeff Farrar, DVM, PhD, MPH, commissioner for food protection, FDA.
Chris Braden, MD, acting director, center for food borne diseases, CDC.
Sherri McGarry, emergency coordinator, food safety branch, FDA.
FDA web site.
Black Rice Is Cheap Way to Get Antioxidants
Study Shows Black Rice Is Good Source of Healthy Antioxidants and Vitamin E
By Bill Hendrick
Inexpensive black rice contains health-promoting anthocyanin antioxidants,
similar to those found in blackberries and blueberries, new research from
Louisiana State University indicates.
"Just a spoonful of black rice bran contains more health promoting
anthocyanin antioxidants than are found in a spoonful or blueberries, but
with less sugar and more fiber and vitamin E antioxidants," Zhimin Xu, PhD,
of Louisiana State University Agricultural Center, says in a news release.
"If berries are used to boost health, why not black rice and black rice
bran?"
Xu and colleagues analyzed samples of black rice bran from rice grown in the
Southern U.S.
He says black rice bran would be a unique and inexpensive way to increase
people's intake of antioxidants, which promote health.
Black rice is rich in anthocyanin antioxidants, substances that show promise
for fighting cancer, heart disease, and other health problems, Xu says.
He adds that food manufacturers could use black rice bran or bran extracts
to boost the health value of breakfast cereals, beverages, cakes, cookies,
and other foods.
Black Rice vs. Brown Rice
The most widely produced rice worldwide is brown. Millers of rice remove the
chaff, or outer husks, from each grain to make it brown.
White rice is made when rice is milled more than is done for brown rice; the
bran is also removed, Xu says.
The bran of brown rice contains high levels of one of the vitamin E
compounds known as "gamma-tocotrienol" as well as "gamma-oryzanol"
antioxidants.
Many studies have shown that these antioxidants can reduce blood levels of
LDL "bad" cholesterol and may fight heart disease.
So black rice bran may be even healthier than brown rice, Xu says.
He and his colleagues also showed that pigments in black rice bran extracts
can produce a variety of colors, from pink to black, and may be a healthier
alternative to artificial food colorants that manufacturers now add to some
foods and beverages.
He writes that several studies have linked some artificial colorants to
cancer, behavioral problems in children, and other adverse health effects.
Currently, black rice is used mainly in Asia for food decoration, noodles,
sushi, and pudding, and Xu says that he would like to see it eaten by more
Americans.
Black rice bran could be used to boost the health value of foods, such as
snacks, cakes, and breakfast cereals, Xu and his colleagues suggest.
This study was presented at a medical conference in Boston. The findings
should be considered preliminary because they have not yet undergone the
"peer review" process, in which outside experts scrutinize the data prior to
publication in a medical journal.
Source:
News release, American Chemical Society.
2010 National Meeting of the American Chemical Society, Boston, Aug. 22-26,
2010.
Type 2 Diabetes May Have Link to Alzheimer's
Study Shows Insulin Resistance May Raise Risk of Brain Plaques Associated
With Alzheimer's
By Denise Mann
People with insulin resistance or type 2 diabetes may be at increased risk
for developing telltale brain plaques that are closely linked to Alzheimer's
disease, a study shows.
The new findings, which appear in the Aug. 25 issue of Neurology, may give
more evidence of the connection between diabetes and Alzheimer's disease.
In insulin resistance, the hormone insulin, produced by the pancreas,
becomes less effective in lowering blood sugar. People with insulin
resistance are at risk for developing type 2 diabetes.
"Type 2 diabetes and Alzheimer's disease are two epidemics growing at
alarming levels around the world," says study researcher Kensuke Sasaki, MD,
PhD, with Kyushu University in Fukuoka, Japan, in a news release. "With the
rising obesity rates and the fact that obesity is related to the rise in
type 2 diabetes, these results are very concerning."
Checking for Signs of Alzheimer's
In the new study, 135 Japanese men and women underwent diabetes screening
tests in 1988 and were followed for up to 15 years for signs of Alzheimer's
disease. Overall, 16% showed signs of clinical Alzheimer's disease before
they died; 65% of people in the study also showed evidence of plaques in
their autopsied brains after death.
People who had abnormal results on their blood sugar tests were more likely
to have plaques in their brain, the study shows. This relationship was more
pronounced among people who also had a form of the ApoE gene that's been
linked to a higher risk of developing Alzheimer's disease.
There was no link between insulin resistance and type 2 diabetes and risk
for developing brain tangles, another brain abnormality seen with
Alzheimer's disease, the study shows.
"Further studies are needed to determine if insulin resistance is a cause of
the development of these plaques," Sasaki says. If it is, "it's possible that
by controlling or preventing diabetes, we might also be helping to prevent
Alzheimer's disease."
The new study "supports the hypothesis that insulin resistance and type 2
diabetes is causally related to a higher risk of dementia including
Alzheimer's disease," writes Jose A. Luchsinger, MD, MPH, in an accompanying
editorial.
More studies are needed to figure out precisely how the conditions are
connected, he writes.
"This is urgent considering that over half of the U.S. population in the age
group most at risk for cognitive impairment has prediabetes or type 2
diabetes," he writes.
Some current trials are looking at how available insulin-sensitizing drugs
affect cognitive impairment.
Sources:
Matsuzaki, T. Neurology, Aug. 31, 2010; vol 75: pp 764-770.
Luchsinger, J.A. Neurology, Aug. 31, 2010; vol 75: pp 758-759.
News release, American Academy of Neurology.
New Drug May Treat Advanced Melanoma
No Cure, but Study Shows New Melanoma Drug Far Better Than Standard
Treatment
By Daniel J. DeNoon
It's no cure, and it works only for about half of melanoma patients, but a
new drug extends progression-free survival in patients dying of advanced
melanoma.
The vast majority of patients with advanced, metastatic melanoma gain only a
few months extra survival from standard treatment. But early tests show that
an experimental drug, dubbed PLX4032 by Plexxikon and Roche Pharmaceuticals,
offers far greater benefits.
The findings are particularly amazing as they come from a very early, phase
I clinical trial. Study leader Keith T. Flaherty, MD, is director of
developmental therapeutics at Massachusetts General Hospital.
"For those who respond to treatment, the average duration of
progression-free survival is nine months," Flaherty tells. "Some
patients are over a year and a half and cruising to two years. In melanoma,
that is good. ... The average time for standard treatment is two months."
There is a catch. The drug targets a specific genetic mutation that helps
melanoma tumor cells grow. Some 40% to 60% of melanoma patients have tumors
with this mutation.
For those who don't, the drug offers no help and possible harm. Fortunately,
a simple genetic test identifies patients likely to respond to the drug.
In its initial phase, the study enrolled 55 patients, 49 with metastatic
melanoma. An additional 32 patients with metastatic melanoma enrolled in the
study's extension phase. All patients carried the BRAF mutation targeted by
the new drug.
The result: 81% of patients with BRAF-positive melanoma responded to
treatment. Duration of response ranged from two to over 18 months. Three of
the melanoma patients no longer had detectable tumor in their bodies,
although Flaherty says such "complete responses" are not the same as cures.
"These results represent a major breakthrough," write Keiran S.M. Smalley,
PhD, and Vernon K. Sondak, MD, of Tampa's Moffitt Cancer Center in an
editorial that accompanies the Flaherty team's report in the Aug. 26 issue
of the New England Journal of Medicine. Smalley and Sondak were not involved
in the Flaherty study.
The drug "seems to be extremely effective and causes a very high response
rate that happens pretty quickly," Sondak tells . "It can cause improvement
even in people who failed standard treatments. It shows a benefit even in
patients with tumors in their livers and other places where
traditional treatment bogs down a lot."
New Melanoma Drug: Making It Better
Yes, the drug -- a pill taken twice daily -- has side effects. The most
common ones are a rash, sun sensitivity, joint discomfort, and fatigue. A
number of patients also developed non-deadly squamous-cell carcinomas on the
skin. Flaherty says these side effects tend to be moderate and manageable --
and that patients have a good quality of life while on therapy.
The drug's most important drawback is that it isn't a cure. Eventually,
tumor cells find new ways to grow and become resistant to the new drug.
"Nine months extra progression-free survival is not what patients come to us
for," Flaherty says. "But we think there are ways to make it better."
"While we need a lot of research, there are many achievable ways to combat
that resistance," Sondak says. "Once we understand it a little better and
develop new drug combinations, we can keep moving the bar and get responses
in more people that last longer and longer. Maybe, eventually, even to the
point where we cured this person."
New Melanoma Drug: Turning Point for Cancer Research?
Sondak says that the new drug's success has huge implications for the entire
field of cancer research.
"What I think is exciting is the broad perspective: Melanoma isn't the only
cancer with this mutation, just the one where it is most common," he says.
"And what's really good news is the success of this idea that you can target
a cancer gene and do something good. Now we can start looking for similar
mutations in other genes important in other cancers. We now have another
proof that this is a fertile line of research."
Today's exciting results come just eight years after the first genetic study
found that the BRAF mutation is important for tumor growth.
"So in a very short time, from discovery of the mutation to publication of
the Flaherty trial results, we went through all those individual steps and
went very, very quickly to a point where everyone could see we had a drug
with much better responses than any other melanoma treatment," Sondak says.
"To me that is the excitement. It shows the cancer research we are doing is
paying off."
What Should Today's Melanoma Patients Do?
Despite all this excitement, the reality is that PLX4032 is not yet ready
for prime time. A phase III clinical trial is now enrolling patients with
BRAF-positive tumors. In that trial, some patients will get the drug (in a
version dubbed RO5185426) and others will get standard treatment.
Only after this trial is completed and analyzed will it be known whether the
drug truly works -- and only then will it be available to patients.
There's a bit more good news for the future. A similar drug from
GlaxoSmithKline, called GSK2118436, is enrolling patients in a phase II
study.
What Should Today's Melanoma Patients Do?
"The bottom line is that if I were a patient, I would be looking for either
one in a clinical trial," Flaherty says.
Another big question is what the new drug might mean for patients with
early-stage melanoma. Stage I tumors can be cured with surgery. But melanoma
is infamous for how quickly it can spread through the body from a small skin
tumor. About half of patients with metastatic melanoma had previously had
apparently curative melanoma surgery.
It's not at all clear whether giving one of the new BRAF inhibitors to such
patients would keep their cancers from coming back.
"Getting to the clinical trial evaluation of this is urgent and we are
getting that under way," Flaherty says. "We don't know if eradicating
microscopic cancer cells is the same trick as beating down large tumors. But
with two other targeted therapies, Gleevec and Herceptin, it does appear
that they truly can prevent recurrences. We are just as hopeful for this
drug."
Sources:
Flaherty, K.T. The New England Journal of Medicine, Aug. 26, 2010; vol 363:
pp 809-819.
Smalley, K.S.M. and Sondak, V.K. The New England Journal of Medicine, Aug.
26, 2010; vol 363: pp 876-878.
Keith T. Flaherty MD, director of developmental therapeutics, cancer center,
Massachusetts General Hospital, Boston.
Vernon K. Sondak, MD, chair, department of cutaneous oncology, Moffitt
Cancer Center, Tampa, Fla.
Clinical Trials.gov.
Broccoli, Plantains May Stop Crohn's Disease Relapse
Broccoli and Plantain Fibers Prevented E. Coli Movement by 45% to 82% in
Study
By Bill Hendrick
Fibers from broccoli and plantain plants may block a key stage in the
development of Crohn’s disease, a new study finds.
Crohn’s is an inflammatory bowel disorder that affects about seven of every
100,000 people in North America.
Researchers in Europe tested soluble fibers from broccoli, plantains, leeks,
apples, and the food processing additives polysorbate 60 and 80. They wanted
to see if the fibers could reduce the movement of E. coli bacteria across
cells lining the bowel, perhaps protecting against Crohn’s disease.
They found that broccoli and plantain fibers prevented E. coli movement by
between 45% and 82%; leek and apple fibers showed no impact. The food
additive polysorbate 80, however, substantially increased E. coli movement.
Plant Fibers Help Against Crohn’s
Results were confirmed in tissue samples taken from patients undergoing
surgery for other disorders of the digestive tract.
Researchers conclude that supplementing diets with fibers from broccoli and
plantains might prevent relapse of Crohn’s disease. One of the key stages in
the development of Crohn’s occurs when cells lining the bowel are attacked
by bacteria, especially E. coli.
Crohn’s disease most often affects the small and large intestines, but may
occur in any area of the digestive tract. It most often occurs in people
between the ages of 15 and 40. The main symptoms include abdominal pain,
persistent diarrhea, fever, fatigue, and loss of appetite.
Crohn’s Disease Common in Developed Countries
Crohn’s disease is common in the United States and other developed countries
where the typical diet is low in fiber and high in processed food. The
researchers conclude that more research is needed to determine the effects
of dietary changes in soluble plant fibers on Crohn’s disease.
The study, by scientists at the University of Liverpool in England,
Linkoping University in Sweden, and at the Rowett Institute of Nutrition and
Health at the University of Aberdeen in Scotland, is published in the
journal Gut.
Source:
News release, University of Liverpool.
Roberts, C. Gut, published online August 2010.
Short-Term Overeating Has Lasting Impact
Study Shows Long-Term Weight Gain Can Result From Just 1 Month of Overeating
By Kathleen Doheny
Overeating even for short periods of time appears to have long-term effects,
according to a new study that lends some scientific oomph to the old saying
about "a moment on the lips, forever on the hips."
''Our study suggests that a short period of hyper-alimentation [overeating]
can have later long-term effects by increasing body weight and fat mass in
normal-weight individuals," says researcher Asa Ernersson, a PhD student at
Linkoping University in Sweden.
The study is published in Nutrition & Metabolism.
Effects of Overeating: Study Details
Ernersson tracked 18 men and women, average age 26, who increased their
energy intake by about 70% and capped their physical activity at no more
than 5,000 steps a day (roughly 2.5 miles) for four weeks.
''The participants' daily energy intake before the study was on average
about 2,270 calories per day and during the intervention they increased
their daily energy intake by an average of 70% compared to before the
intervention," Ernersson tells.
That translates to nearly 4,000 calories a day.
The diet was not healthy. "During the intervention the diet was mainly from
fast foods, [such] as hamburger, pizza and french fries," Ernersson says.
Ernersson evaluated weight, body mass index, and other data at the start of
the study, after the four-week eating binge, again six and 12 months later,
and two and a half years later. He compared the feasting group with another
group of 18 (average age 25) who didn't feast or have a cap on their
physical activity.
The results:
The feasting group gained an average of 14 pounds after their one-month
binge, while body weight overall in the comparison group stayed the same.
At six months, the feasting participants had lost about 50% of the weight
gain but still had higher body weight than they did at the study start. Five
participants had returned to nearly the weight they had at the start.
At 12 months, the overall weight of the feasting group was still higher than
at the study start.
At 2.5 years, the weight of the comparison group was the same overall, but
those in the feasting group had a further rise. The average weight at study
start -- 149 pounds -- had risen to an average of 160 pounds.
Fat mass also increased in those who feasted -- from 20% of total body
weight to nearly 24% after one month. At 12 months, it went down to 22.6%,
but was still higher than at the study start
The change in fat mass was larger than expected, according to Ernersson.
"Based on this, it can be recommended to avoid very high food intake that
might occur during shorter periods," Ernersson says. The researcher concedes
that the study has limitations and that the findings need to be confirmed in
future research.
Overeat Now, Pay Later: Other Opinions
The study findings add credibility to what nutrition experts have told us
for years about moderation, says Alice Lichtenstein, DSc, the Gershoff
Professor of Nutrition Science and Policy at the Friedman School at Tufts
University, Boston.
"Given what we currently know, I think the best advice we can give people is
to moderate food intake and physical activity to achieve and maintain a
healthy body weight," she says.
''Although there are times when overindulgence is difficult to avoid, for
example, Thanksgiving Day, it is important to not turn that event into
Thanksgiving weekend."
Another interesting finding of the study, says Joan Salge Blake, RD, a
professor of nutrition at Boston University, is that the feasting seems to
have affected some more than others. "It sounds like some could get back to
their previous weight," she says. But some were not able to.
The take-home message is clearly not to overeat in the first place, says
Blake, who is also a spokeswoman for the American Dietetic Association.
"Once you gain it, it is very challenging to take it off.'' Prevention of
weight gain is the best strategy, she says.
Lichtenstein can't help but wonder what might happen if researchers looked
at the opposite situation: short-term underrating coupled with increased
physical activity, and what effect that might have on body composition
long-term.
Sources:
Asa Ernersson, PhD student, Linkoping University, Sweden.
Ernersson, A. Nutrition & Metabolism, Aug. 25, 2010.
Joan Salge Blake, RD, professor of nutrition, Boston University;
spokeswoman, American Dietetic Association.
Alice H. Lichtenstein, DSc, Gershoff Professor of Nutrition Science and
Policy, Friedman School, Tufts University, Boston.
First Biosynthetic Corneas Implanted
Nerve, Cell Regeneration Occurred in Nine of 10 Patients
By Salynn Boyles
Corneas made in the lab using genetically engineered human collagen could
restore sight to millions of visually impaired people waiting for
transplants from human donors, researchers say.
In a newly released study, investigators from Canada and Sweden reported
results from the first 10 people in the world treated with the biosynthetic
corneas.
Two years after having the corneas implanted, six of the 10 patients had
improved vision. Nine of the 10 experienced cell and nerve regeneration,
meaning that corneal cells and nerves grew into the implant.
“This is the first time we have been able to regenerate a cornea in humans,”
researcher May Griffith, PhD, of the Ottawa Hospital Research Institute and
the University of Ottawa tells. “We are still in the prototype stage, but
this shows that regenerating a human cornea is possible.”
Too Few Corneas Available
Acting as the window to the eye, the cornea is made up largely of water and
the fibrous protein collagen.
Worldwide, more than 10 million people have impaired vision or blindness as
a result of corneal damage, but only a small fraction ever receive
transplants from cadaver donors.
A shortage of human donor tissue coupled with the threat of graft rejection
from donor corneal transplants has driven the search for other ways of
treating corneal damage. Although synthetic corneal replacements made from
plastic are available, they have many drawbacks and are considered an option
for only a small percentage of people.
It has been 10 years since Griffith and colleagues first reported the
development of a material with the potential to grow healthy new tissue in
people with damaged corneas.
To make the material, the researchers placed a human gene that regulates the
natural production of collagen into specially programmed yeast cells. They
then molded the resulting material into the shape of a cornea.
After several years of testing in her lab, Griffith began collaborating with
Swedish eye surgeon Per Fagerholm of Linkoping University, who implanted the
engineered collagen corneas into the 10 patients in Sweden.
None of the patients experienced graft rejection or required long-term
immune suppression -- two potential side effects with human donor corneal
transplants. The corneas were sensitive to touch and produced normal tears.
The results were published in the journal Science Translational Medicine.
The research was primarily funded by grants from the Canadian Stem Cell
Network, the Swedish Research Council, and the Marie Curie International
Fellowship. The human collagen used to develop the corneas was provided by
biotechnology company FibroGen Inc.
Researcher: More Study Needed
Griffith and colleagues are in the planning stages of a larger study to test
what she calls an improved version of the lab-made cornea. If results from
that trial prove promising, an even larger study will follow, she says.
“This is one instance in regenerative medicine where we are making good
strides, but we aren’t there yet,” she says.
Ophthalmologist and eye surgeon Walter Stark, MD, agrees.
Stark directs the center for cataract and corneal diseases at the Johns
Hopkins Hospital Wilmer Eye Institute in Baltimore and is a professor of
ophthalmology at Johns Hopkins School of Medicine.
He says the lab-made material used in the study is very fragile, making it
appropriate for patients with surface corneal damage but not for those with
damage to the innermost layer of the cornea, known as the endothelium.
“This research shows the potential for these bioengineered corneas,” he
says. “But the outcomes in this study were not nearly as good as those
achieved with human donor corneas. This may become an excellent technique,
but right now it is not ready for clinical use.”
Sources:
Fagerholm, P. Science Translational Medicine, Aug. 25, 2010; vol 2.
May Griffith, MD, senior scientist, Ottawa Hospital Research Institute;
professor, department of cellular and molecular medicine and ophthalmology,
University of Ottawa.
Walter Stark, MD, distinguished professor of ophthalmology, Johns Hopkins
School of Medicine; director, cataract and corneal disease center, Johns
Hopkins Hospital Wilmer Eye Institute.
News release, Ottawa Hospital Research Institute.
News release, FibroGen Inc.
Stress May Raise Risk of Premenstrual Syndrome
Study Shows PMS Symptoms Could Be More Severe if Women Are Stressed Before
Menstruation
By Denise Mann
Feeling stressed out in the weeks preceding your menstrual cycle may raise
your risk for experiencing more severe premenstrual syndrome (PMS) symptoms,
a study shows.
Women who reported high levels of stress in the two weeks before they got
their period were two to three times more likely to experience depression,
sadness, and crying spells as well as physical PMS symptoms such as body
aches, bloating, low back pain, cramps, and headache, compared to women who
did not feel stressed early on in their cycles.
The study appears in the Journal of Women's Health.
"Stress early in the cycle is a risk factor for PMS, and combating stress
with yoga, exercise, biofeedback, or meditation may help prevent PMS
symptoms or make them much more manageable," says study researcher Audra L.
Gollenberg, PhD. She was a postdoctoral fellow at the National Institute of
Child Health and Human Development in Bethesda, Md., when she conducted the
study.
"The symptoms may not go away completely, but stress-reduction techniques
could make symptoms more manageable to the point that some women may not
need medication," Gollenberg tells.
"More than 50% of women report some degree of PMS symptoms and this is
responsible for missed days at work, and if we can find things to prevent or
mediate PMS without medications, that is a good thing," says Gollenberg, who
is now an assistant professor of public health at Shenandoah University in
Winchester, Va.
The new study included 259 women ages 18 to 44 who filled out questionnaires
about their stress levels and their physical and psychological PMS symptoms
throughout their four-week cycle. Women also tracked their ovulation using
an at-home fertility monitor. All but nine women reported this information
for two menstrual cycles.
Among women who tracked their stress levels and symptoms for two cycles,
those who were stressed in the weeks before the beginning of one cycle, but
not the other, usually had more severe premenstrual symptoms after the weeks
where they reported more stress.
Women who had high stress before both cycles were 25 times more likely to
experience physical and psychological PMS symptoms than those who reported
low stress before both cycles.
"Developing a stress-reduction intervention and testing to see if it reduces
PMS would be an interesting next step," says Gollenberg.
Window of Opportunity to Treat PMS
The new study "sheds an interesting light on PMS because it shows us that
things are going on at other points in the cycle," says Shari Brasner, MD,
an assistant professor of obstetrics and gynecology at Mount Sinai School of
Medicine in New York City.
Many PMS treatments target the few bad days on or around that time of the
month. But"this opens my eyes and hopefully many others' eyes that we may
have a bigger window of opportunity to intervene, treat, and make a real
difference for women with PMS," she says.
"Starting much earlier may make more sense as would incorporating
non-pharmacological strategies like stress reduction," Brasner tells.
"Relaxation and counseling may help if a woman's stress levels are high,"
agrees Theodoros Vlachos, MD, vice chief of gynecology at Beaumont Hospital
in Royal Oak, Mich. He is not sure if the stress causes the PMS or the
anxiety about upcoming PMS causes the stress. "It may be the
chicken or the egg," he says.
Sources:
Gollenberg, A.L. Journal of Women's Health, May 2010; vol 19: pp 959-967.
Audra L. Gollenberg, PhD, assistant professor, public health, Shenandoah
University, Winchester, Va.
Theodoros Vlachos, MD, vice chief, gynecology, Beaumont Hospital, Royal Oak,
Mich.
Shari Brasner, MD, assistant professor, obstetrics and gynecology, Mount
Sinai School of Medicine, New York City.
Courtesy: Rasool Simjee |
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Rasool Simjee