Scientists Stem cells created from eggs
Thu, 28 Jun 2007 12:07:59 GMT
By MALCOLM RITTER, AP Science Writer
NEW YORK - Scientists say they've created embryonic stem cells by stimulating unfertilized eggs, a significant step toward producing transplant tissue that's genetically matched to women.
The advance suggests that someday, a woman who wants a transplant to treat a condition like diabetes or a spinal cord injury could provide eggs to a lab, which in turn could create tissue that her body wouldn't reject.
Ethicists disagreed on whether the strategy would avoid the long-standing ethical objections to creating embryonic stem cells by other means.
Such cells can develop into virtually any tissue of the body, and scientists hope to harness them for producing specialized tissues like nerve cells or pancreas cells to treat a range of illnesses. But the process of harvesting the stem cells destroys embryos, which many people oppose.
To create tissues that genetically match a patient, some scientists are trying to develop a process called therapeutic cloning, in which DNA from the patient is inserted into an unfertilized egg, an embryo is produced and stem cells are harvested. But nobody has made that work in humans.
The new work tries another tack: stimulating a woman's unfertilized egg to begin embryonic development. Scientists believe this development can't continue long enough to produce a baby, but as the new work shows, it can produce stem cells that are genetically matched to the egg donor.
Such an approach could not provide matched cells for men, of course.
The work, published online by the journal Cloning and Stem Cells, is reported by scientists from Lifeline Cell Technology of Walkersville, Md., and from Moscow.
Jeffrey Janus, president of Lifeline and an author of the study, noted that stem cells produced by the method might prove useful for patients other than the egg donor, in combination with anti-rejection therapy. That's the case with standard stem cell lines created from ordinary embryos, he said.
He and colleagues report producing six lines of embryonic stem cells, one of which had chromosome abnormalities. They obtained their eggs from five women who were having eggs harvested for test-tube fertilization, and who agreed to donate some for the research.
"It's a big deal, it's a very nice advance," said Kent Vrana of Pennsylvania State University, who has done similar work in monkeys. The process appears efficient, he said, and it provides "an additional tool" beyond therapeutic cloning.
George Daley, a scientist at the Harvard Stem Cell Institute, called the work interesting.
"It's a new type of embryonic stem cell line from a different kind of embryo," he said. "We just don't know whether these cells will be as good as embryonic stem cells from naturally fertilized embryos."
One question, he said, is whether the lack of a father's DNA contribution would impair the performance of the stem cells. DNA in sperm carries particular markers that differ from those found on DNA in an egg, and these markers affect the activity of specific genes.
Ronald M. Green, a Dartmouth College ethicist, said he believes the egg-stimulation process will prove an ethically acceptable way to create stem cells.
"People will see that these are activated eggs ... they do not of themselves ever develop into a human being," he said. "This is not anything biologically or morally like a human embryo, and it's a very good way of trying to provide human embryonic stem cells that does not involve the destruction of an embryo."
But the Rev. Tad Pacholczyk of the National Catholic Bioethics Center in Philadelphia disagreed.
"My view is that if these grow as organized embryos for the first few days and then arrest, they may just be very short-lived human beings," he said.
"One is very possibly dealing with a defective human being. And at a minimum, the benefit of the doubt should be given here, and these embryos should not be created for the purposes of destroying them."
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On the Net:
Cloning and Stem Cells: http://www.liebertpub.com/clo
Antidepressants not big risk for defects
Thu, 28 Jun 2007 05:40:40 GMT
By JEFF DONN, Associated Press Writer
BOSTON - Newborns face little risk of birth defects from antidepressants taken by many women early in pregnancy, say the reassuring findings of the two biggest studies of this controversial link.
The research focuses on the class of drugs chosen most often for depression and anxiety, including the brands Prozac, Paxil and Zoloft.
Paxil carries a warning of possible heart defects in newborns, and experts don't expect the new research to change that. However, they find the new studies comforting for women struggling with depression.
The possibility of birth defects from antidepressants has put doctors and patients in a tricky quandary. Birth defects obviously hurt newborns, but depressed mothers who can't give proper care also endanger their babies.
Confusing matters, researchers have wondered if the concern about birth defects should extend beyond Paxil to this entire class of drugs, known as selective serotonin-reuptake inhibitors, or SSRIs. The two latest studies, appearing Thursday in The New England Journal of Medicine, relieve some of that worry, say birth specialists.
"Yeah, there's a risk, but the risk overall is probably pretty small," said Dr. Susan Ramin, obstetrics chairman at the University of Texas Medical School in Houston, who was familiar with the findings.
The two studies — one from the federal Centers for Disease Control and the other from Boston University — use more cases of birth defects than previous research to consider links between the abnormalities and SSRIs. The Boston University study was funded partly by the National Institutes of Health and Paxil maker GlaxoSmithKline PLC.
Together, the two studies looked at 19,471 newborns with birth defects and 9,952 without them. Then they considered what SSRIs the mothers in both groups took during the first three months of pregnancy and mapped the patterns of birth defects.
Neither study was able to tie SSRIs as a group to either heart defects or most other defects. That reassurance is especially welcome because depressed women fret even more than other mothers about the health of their newborns, said Dr. Stephan Quentzel, a psychiatrist who treats pregnant women at Beth Israel Medical Center in New York City.
Also, a mother's untreated depression can lead to poor care or turmoil at home, a weaker maternal bond, and other problems for a newborn. "The fetus and the newborn are almost always worse off if the mom is depressed than if ... exposed to the vast majority of antidepressants," Quentzel said.
However, doctors and mothers have been very wary about medications and birth defects since Europe's thalidomide scandal of deformed babies in the 1960s. Defects from all causes are expected in about 3 percent of births, enough to make many mothers nervous.
The concern about SSRIs grew out of GlaxoSmithKline's own alert in 2005 about possible heart defects in newborns whose mothers took Paxil early in pregnancy. The U.S. Food and Drug Administration added its own warning. Last year, a separate study linked SSRIs taken late in pregnancy to a lung disorder in newborns.
The latest studies do not consider that disorder, known as persistent pulmonary hypertension. But they suggest that the risk of other defects from an SSRI — even if confirmed — would add only a fraction of 1 percent to the overall danger, researchers said.
Paxil did appear to triple the risk of a defect in blood flow from the heart, both studies found. But that additional danger would still be modest, experts said.
The studies further hinted at possible ties between other SSRIs and a handful of other defects, but researchers said the numbers of newborns with specific defects were too small to draw strong conclusions.
"Based on these studies, it's correct to say: no major risk," said Carol Louik, a public health expert who led the Boston study. "I wouldn't say, 'No risk.'"
Researchers said women should talk over the potential risks and benefits with their doctors, preferably before pregnancy.
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The New England Journal of Medicine: http://nejm.org/
Birth defects facts from Centers for Disease Control: http://www.cdc.gov/ncbddd/bd/facts.htm
Too much video gaming not addiction yet
Thu, 28 Jun 2007 05:40:09 GMT
By LINDSEY TANNER, AP Medical Writer
CHICAGO - The American Medical Association on Wednesday backed off calling excessive video-game playing a formal psychiatric addiction, saying instead that more research is needed.
A report prepared for the AMA's annual policy meeting had sought to strongly encourage that video-game addiction be included in a widely used diagnostic manual of psychiatric illnesses.
AMA delegates instead adopted a watered-down measure declaring that while overuse of video games and online games can be a problem for children and adults, calling it a formal addiction would be premature.
"While more study is needed on the addictive potential of video games, the AMA remains concerned about the behavioral, health and societal effects of video game and Internet overuse," said Dr. Ronald Davis, AMA's president. "We urge parents to closely monitor children's use of video games and the Internet."
Despite a lack of scientific proof, Jacob Schulist, 14, of Hales Corners, Wis., says he's certain he was addicted to video games — and that the AMA's vote was misguided.
Until about two months ago, when he discovered a support group called On-Line Gamers Anonymous, Jacob said he played online fantasy video games for 10 hours straight some days.
He said his habit got so severe that he quit spending time with family and friends.
"My grades were horrible, I failed the entire first semester" this past school year because of excessive video-game playing, he said. "It's like they're your life."
Delegates voted to have the AMA encourage more research on the issue, including seeking studies on what amount of video-game playing and other "screen time" is appropriate for children.
Under the new policy, the AMA also will send the revised video-game measure to the American Psychiatric Association, asking it to consider the full report in its diagnostic manual; the next edition is to be completed in 2012.
Dr. Louis Kraus, a psychiatric association spokesman, said the report will be a helpful resource.
The AMA's report says up to 90 percent of American youngsters play video games and that up to 15 percent of them — more than 5 million kids — might be addicted.
The report, prepared by the AMA's Council on Science and Public Health, also says "dependence-like behaviors are more likely in children who start playing video games at younger ages."
Internet role-playing games involving multiple players, which can suck kids into an online fantasy world, are the most problematic, the report says. That's the kind of game Schulist says hooked him.
Kraus, chief of child and adolescent psychiatry at Chicago's Rush Medical Center, said behavior that looks like addiction in video-game players may be a symptom of social anxiety, depression or another psychiatric problem.
He praised the AMA report for recommending more research.
"They're trying very hard not to make a premature diagnosis," Kraus said.
In other action on the final day of the AMA's annual policy meeting, delegates:
• Voted to have the AMA support government policies requiring fast-food restaurant chains to provide menus detailing nutritional information including calories, fat and sodium content. A key way to fighting the obesity epidemic "is that people know what they're eating," Davis said.
• Recommended more research on a potential link between high fructose corn syrup and obesity. A measure had sought to have the AMA seek government restrictions on the popular sweetener and food labels declaring that excessive consumption of it may lead to obesity.
• Rejected a move to lobby for limits on the noise levels of in-ear headphones used with iPods and other music-playing devices. A resolution supporting limits said devices with in-ear headphones can generate sound well above 100 decibels — more noise than a chain saw makes and levels that have been linked with permanent hearing loss. AMA delegates voted instead to seek more research on the issue.
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On the Net:
AMA: http://www.ama-assn.org
On-Line Gamers Anonymous: http://www.olganon.org
Study With calcium food trumps pills
Wed, 27 Jun 2007 23:20:45 GMT
By CHERYL WITTENAUER, Associated Press Writer
ST. LOUIS - Most women know that calcium is critical in preventing osteoporosis, the disease of progressive bone loss and fractures that affects millions of Americans.
But which source is better — calcium-rich foods or supplements? A preliminary study by researchers at Washington University School of Medicine suggests dietary calcium may be better at protecting bone health.
Though not definitive, the study found that women who get most of their daily calcium from food have healthier bones and higher bone density than women whose calcium comes mainly from supplemental tablets.
That was true even though the supplement-takers had higher average levels of calcium.
Calcium from dietary sources is generally better absorbed than that from supplements, which could help explain the difference, said the study's lead author, Dr. Reina Armamento-Villareal.
Those getting calcium from foods also had more estrogen in their bodies; the hormone is needed to maintain bone mineral density. Researchers can't yet explain the food-estrogen connection.
The research is preliminary and offers "a springboard to do something more, a hypothesis to test," said Armamento-Villareal, a bone specialist and assistant professor in the School of Medicine's division of bone and mineral diseases. It was published in the May issue of the American Journal of Clinical Nutrition.
Researchers asked 183 postmenopausal women to meticulously document their diet and their calcium supplement intake for seven days. They tested their bone mineral density and their urine for levels of estrogen.
The women then were divided into three groups: those who got at least 70 percent of their daily calcium from supplements, those who got the same amount from dairy products and other food, and those whose calcium-source percentages fell somewhere in between.
The "diet group" took in the least calcium, an average of 830 milligrams per day. Yet, the group had higher bone density in their spines and hip bones than women in the "supplement group," who consumed 1,030 milligrams per day.
Women in the "diet plus supplement group" tended to have the highest bone mineral density as well as the highest calcium intake at 1,620 milligrams per day.
An analysis showed that women in the "diet group" and the "diet plus supplement group" had higher levels of estrogen, needed for bone mineral density.
Dr. Robert Recker, who heads osteoporosis research at the Creighton University School of Medicine in Omaha, noted weaknesses in the study, which he said "is certainly not definitive."
Those who got calcium from their diet might have also taken in more vitamin D from milk, which would aid in calcium absorption. As for the estrogen connection, they might have eaten plant sources containing more of the hormone, he said.
"Nevertheless it's not to be ignored," Recker said. "Observation studies are very good for generating a hypothesis to be tested later in an outright experiment."
Dairy foods and calcium-fortified orange juice are excellent sources of calcium. Dark green, leafy vegetables also contain it, though it is not as readily absorbed as calcium from dairy, researchers said.
Armamento said she'd like to do a long-term study of teenagers whose bones are still developing to see what, if any, differences might emerge among young women taking calcium from diet versus supplements.
"It's a lifestyle issue," she said, noting that some teenagers avoid dairy products.
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On the Net:
American Journal of Clinical Nutrition: http://www.ajcn.org/
Washington University School of Medicine: http://medschool.wustl.edu/
Creighton University Medical Center, Osteoporosis Research Center:
http://osteoporosis.creighton.edu/
Overweight elderly don39t have higher death rates
Thu, 28 Jun 2007 18:44:17 GMT
NEW YORK -
After the age of 80, carrying a
few extra pounds may not subtract years from your lifespan, a
new study from Japan shows.
Among a group of 80-year-olds followed for four years, the
researchers found that underweight individuals were more likely
to die from cancer, heart disease or pneumonia than
normal-weight or overweight people. &;Overweight status was
associated with longevity and underweight with short life,&; Dr.
Yutaka Takata and colleagues from Kyushu Dental College in
Kitakyushu City conclude.
While being overweight has been tied to a greater risk of
heart disease, studies have also found that being underweight
with heart disease may carry an increased risk of morbidity and
mortality, Takata and his team note.
To better understand the controversial relationship between
body mass index and mortality from heart disease, as well
as all-cause mortality, the researchers looked at men and women
who were 80-years-old.
Fifty-two were underweight, with an average BMI of 17.2;
another 468 were normal-weight, with BMIs averaging 21.8; and
155 were overweight, with an average BMI of 27.3. Just five
people in the study were obese ,
so they were included in the overweight group. People with BMIs
between 18.5 and 25 are considered normal weight, while
individuals with BMIs of 25 or greater are classified as
overweight.
Mortality rates from heart disease, pneumonia and cancer
for normal-weight and overweight individuals weren't
significantly different, the researchers found. But underweight
men and women were nearly four times as likely to die from any
cause compared with as overweight individuals, and nearly 18
times more likely to die from cancer. Heart disease mortality
in the underweight group was almost four times greater than
among normal-weight individuals.
Other studies have found a protective effect of extra
pounds among older individuals, Takata and his colleagues note;
for example, among elderly US men, the lowest mortality is seen
among men with BMIs of 26 and among women with BMIs of 29.6.
While Takata and his colleagues attempted to control for the
effects of illness, it is still possible that existing disease
accounted for some of the increased mortality risk seen among
the underweight individuals, they note.
&;It is likely that only mild obesity (but not severe
obesity) or overweight status in older people and in patients
with heart disease may be associated with a lower mortality
rate from any disease, as well as with lower mortality from
cardiovascular disease,&; the researchers conclude.
SOURCE: Journal of the American Geriatrics Society, June
2007.
