SUNDAY - October 7, 2007----------------------------------------News Archive/Return to Today's News Alerts

Moving Story of Woman Who Made a Stem Cell Breakthrough.

Alone after losing her husband and daughter in a Russian flu epidemic, 60-year-old Elena Revazova came to California in 1997 and began looking for distant relatives. She had been the chief scientist at Russia's national cancer institute. But in the United States she lived in obscurity, taking a volunteer research job at the University of California Los Angeles veterans hospital because she figured no one would hire a 60-year-old woman with poor English, despite two Ph.D.s and a medical degree.

A decade later, Revazova's work is back in the scientific spotlight. An Oceanside company she helped start, International Stem Cells, gained worldwide attention with the publication last summer of work done by Revazova and her team of scientists, who coaxed unfertilized human eggs to produce embryonic stem cells.

The company showed that the embryonic stem cells could be grown into more human embryonic stem cells, as well as differentiated into some of the 200 different cell types in the body.

That work, scientists said, could provide a source of human embryonic stem cells that sidestep the moral ethical debate swirling around the cells. It could also provide a source of stem cells that would not provoke a negative immune response when injected into humans – at least in women who provide the eggs.

“It's a big deal, it's a very nice advance,” said Kent Vrana of Pennsylvania State University, when the article was published online in the journal Cloning and Stem Cells. Vrana had done similar work in monkeys.

The company is the first to intentionally create these so-called human parthenogenetic cells – though another article published last summer suggested that Korean stem cell researcher Woo Suk Hwang may have created parthenogenetic cells when he falsely claimed instead to have cloned human embryonic stem cells.

International Stem Cell is hoping to create a bank of these parthenogenetic stem cells that can be used by researchers around the globe, and to use cells to create new therapies for diabetes and diseases of the eye and liver.

This month, a scientific journal article by the company showed that they turned the embryonic stem cells into cornea tissue. The company, which went public in January through a reverse merger with an inactive company, has been selling shares over the counter. Shares closed yesterday at $1.15, up 5 cents.

The founding of the company goes back to Revazova volunteering at the VA hospital. more...

Article by Terri Somers, September 28, 2007 a UNION-TRIBUNE STAFF WRITER.

FDA Officials Hope To Boost Generic Drug Approvals.

The U.S. Food and Drug Administration announced an internal initiative that agency officials hope will result in additional generic drugs approved annually. Agency officials concede they've struggled to keep up with a growing number of generic drug applications. In fiscal year 2007, which ended Sept. 30, the FDA approved a record 682 generic drug applications, but it also received a record 880 applications, which added to a backlog of drug applications. From about 1999 to 2003 the agency received roughly 300 applications annually.

Gary Buehler, the director of the FDA's Office of New Drugs, said the current backlog is about 1,300 applications, up from 800 last year. Half of those can't be fully processed, however, because the brand-name drug the generic drug maker is seeking to copy hasn't yet lost patent protection or exclusivity. The agency is supposed to review generic drug applications within six months, but the average review time is about 16 months. Until recently the agency had a first-in, first-out policy. Now, Buehler said the agency is prioritizing applications for first generic products if there are no blocking patents or exclusivity protections on the reference listed drug, or the brand name drug. A first generic product is the first generic for particular brand-name drug.

The agency said it was streamlining certain procedures for generic drug reviews on technical issues involving chemistry and manufacturing issues and conducting team reviews of multiple applications of the same drug product. The agency also said it would step up efforts to train generic drug makers on proper drug application submissions.

Published September 13, 2007 at Cell Stem Cell.

Something in the Way She Moves?

In a particularly stimulating study, researchers have found that lap dancers--women who work in strip joints and, for cash, gyrate in the laps of seated men--earn more when they are in the fertile phase of their menstrual cycle. The finding suggests that women subtly signal when they are most fertile, although just how they do it is not clear.

Women, unlike many mammals, don't come into heat or estrus, a state of obvious fertility that attracts potential mates. Common wisdom has it that estrus was lost as humans evolved. The notion is that women evolved "concealed ovulation" along with around-the-month sexual receptivity the better to manipulate males by keeping them in the dark, says Geoffrey Miller, an evolutionary psychologist at the University of New Mexico in Albuquerque. But now Miller and colleagues have found evidence that a woman’s state of fertility may not be so secret after all.

Over a 60-day period, the researchers collected data from 5300 lap dances. They divided the answers according to whether the dancers were in the menstrual phase, the high-fertility estrous phase, or the luteal phase. The result, as they report online this week in the journal Evolution and Human Behavior: Of the 11 women with normal menstrual cycles, those in the estrous phase pulled in about $70 an hour--compared with $50 for those in the luteal phase, and only $35 an hour for those who were menstruating. The other seven women were on birth control pills. They earned less across the board, and there was no peaking at the estrous phase.

"Current nerve blocks cause paralysis and total numbness," Dr. Woolf says. "This new strategy could profoundly change pain treatment in the perioperative setting."

Published October 4, 2007 in Evolution and Human Behavior.

Discovery May Explain Why Cancer Cells Never Stop Dividing.

A group working at the Swiss Institute for Experimental Cancer Research (ISREC) in collaboration with the University of Pavia has discovered that telomeres, the repeated DNA-protein complexes at the end of chromosomes that progressively shorten every time a cell divides, also contain RNA. This discovery, published online October 4 in Science Express, calls into question our understanding of how telomeres function, and may provide a new avenue of attack for stopping telomere renewal in cancer cells.

Inside the cell nucleus, all our genetic information is located on twisted, double stranded molecules of DNA which are packaged into chromosomes. At the end of these chromosomes are telomeres, zones of repeated chains of DNA that are often compared to the plastic tips on shoelaces because they prevent chromosomes from fraying, and thus genetic information from getting scrambled when cells divide. The telomere is like a cellular clock, because every time a cell divides, the telomere shortens. After a cell has grown and divided a few dozen times, the telomeres turn on an alarm system that prevents further division. If this clock doesn’t function right, cells either end up with damaged chromosomes or they become “immortal” and continue dividing endlessly – either way it’s bad news and leads to cancer or disease. Understanding how telomeres function, and how this function can potentially be manipulated, is thus extremely important.

The DNA in the chromosome acts like a sort of instruction manual for the cell. Genetic information is transcribed into segments of RNA that then go out into the cell and carry out a variety of tasks such as making proteins, catalyzing chemical reactions, or fulfilling structural roles. It was thought that telomeres were “silent” – that their DNA was not transcribed into strands of RNA. The researchers have turned this theory on its head by discovering telomeric RNA and showing that this RNA is transcribed from DNA on the telomere.

Why is this important" In embryonic cells (and some stem cells), an enzyme called telomerase rebuilds the telomere so that the cells can keep dividing. Over time, this telomerase dwindles and eventually the telomere shortens and the cell becomes inactive. In cancer cells, the telomerase enzyme keeps rebuilding telomeres long past the cell’s normal lifetime. The cells become “immortal”, endlessly dividing, resulting in a tumor. Researchers estimate that telomere maintenance activity occurs in about 90% of human cancers. But the mechanism by which this maintenance takes place is not well understood. The researchers discovered that the RNA in the telomere is regulated by a protein in the telomerase enzyme. Their discovery may thus uncover key elements of telomere function.

The prevalence of dermoid sinus in the dogs, a painful disorder where the skin fails to separate from the nerve chord, affects nearly one-tenth of Rhodesian ridgebacks, says team-member Claire Wade. “Often the animals have to be put down,” she says. Dogs lacking the duplication of genes are unridged; those with one copy have a normal ridge; but having two copies also carries an 80% risk of dermoid sinus. The mechanism paves the way for geneticists to use the dog genome to help identify genes involved in disorders such as diabetes that also affect humans.

Published October 4, 2007 in Science Express.

FRIDAY - October 5, 2007----------------------------------------News Archive/Return to Today's News Alerts

Eat Fish While Pregnant Says National Healthy Mothers, Healthy Babies coalition.

Women who want to become pregnant, are pregnant or breast-feeding should eat at least 12 ounces of fatty fish such as tuna every week to help themselves and their babies.

Fish including mackerel, sardines, light tuna and salmon are rich in omega-3 fatty acids - components of fat known to help brain development. Walnuts, flaxseed oil and leafy green vegetables also contain the compounds.

Women need the nutrients to prevent postpartum depression and babies need them for brain and motor skill development, the National Healthy Mothers, Healthy Babies (HMHB) coalition says.

The coalition, which includes the American Academy of Pediatrics, the National Institute on Child Health and Human Development and the Centers for Disease Control and Prevention, says "90 percent of women are consuming less than the recommended amount of fish."

The HMHB coalitiona recommends eating a minimum of 12 ounces per week of fish like salmon, tuna, sardines and mackerel, and can do so safely. The Group found that eating fish is the optimal way to gain the benefits of long-chain omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Seafood is the richest dietary source of DHA and EPA in Americans’ diets. The Group also recognized that selenium, an essential mineral found in certain ocean fish, accumulates and appears to protect against the toxicity from trace amounts of mercury. Mercury is released mainly in industrial and power-plant emissions. It settles into lakes and oceans and builds up in the flesh of fish and the animals that eat the fish. So choose your fish wisely and eat leafy green vegetables as well when pregnant.

Published October 4, 2007 at National Healthy Mothers, Healthy Babies: For Pregnant Women, Benefits of Eating Ocean Fish Outweigh Concerns from Trace Levels of Mercury.

Found - Connection Between Caloric Restriction and Longevity.

For nearly 70 years scientists have known that caloric restriction prolongs life. In everything from yeast to primates, a significant decrease in calories can extend lifespan by as much as one-third. But getting under the hood of the molecular machinery that drives this longevity has remained elusive. Now researchers
from Harvard Medical School, in collaboration with scientists from Cornell Medical School and the National Institutes of Health, have discovered two genes in mammalian cells that act as gatekeepers for cellular longevity. When cells experience certain kinds of stress, such as caloric restriction, these genes rev up and help protect cells from diseases of aging.

“We’ve reason to believe now that these two genes may be potential drug targets for diseases associated with aging,” says David Sinclair, associate professor of pathology at Harvard Medical School and senior author on the paper. The new genes that Sinclair’s group have discovered, in collaboration with Anthony Sauve of Cornell Medical School and Rafael de Cabo of NIH, are called SIRT3 and SIRT4. They are members of a larger class of genes called sirtuins. (Another gene belonging to this family, SIRT1, was shown last year to also have a powerful impact on longevity when stimulated by the red-wine molecule resveratrol.) In this paper, the newly discovered role of SIRT3 and SIRT4 drives home something scientists have suspected for a long time: mitochondria are vital for sustaining the health and longevity of a cell.

Mitochondria, a kind of cellular organ that lives in the cytoplasm, are often considered to be the cell’s battery packs. When mitochondria stability starts to wane, energy is drained out of the cell, and its days are numbered. In this paper, Sinclair and his collaborators discovered that SIRT3 and SIRT4 play a vital role in a longevity network that maintains the vitality of mitochondria and keeps cells healthy when they would otherwise die. When cells undergo caloric restriction, signals sent in through the membrane activate a gene called NAMPT. As levels of NAMPT ramp up, a small molecule called NAD begins to amass in the mitochondria. This, in turn, causes the activity of enzymes created by the SIRT3 and SIRT4 genes - enzymes that live in the mitochondria - to increase as well. As a result, the mitochondria grow stronger, energy-output increases, and the cell’s aging process slows down significantly. (Interestingly, this same process is also activated by exercise.)

Published September 21, 2007 in Cell.


p53 Key Player in Cell’s Ability to Detect and Repair DNA Damage.

Scientists know that inside each cell, a little engine called RNA polymerase II does one essential job: It copies instructions from genes in the nucleus that get carried to production units in the rest of the cell to support our daily needs. Now researchers at the University of Michigan Medical School have shown that RNA polymerase II also constantly scans the cell’s DNA for damage. When certain types of damage in DNA halt the action of RNA polymerase II, a stress signal is generated that alerts a key tumor-suppressor protein called p53.

p53 is a master protein that responds to DNA damage by marshaling hundreds of genes to repair or eliminate damaged cells, have been the subject of thousands of studies. Mutations in the p53 gene occur in more than half of all cancers.

Finding and repairing DNA lesions is a non-stop job for cells.

As many as 20,000 lesions occur daily in a cell’s DNA, Ljungman says. Many stresses result from oxidation and other internal cell processes. In addition, our DNA is also challenged by sunlight, radiation and reactive chemicals found in food. “So much damage happens all the time,” Mats Ljungman, Ph.D., a University of Michigan Medical School researcher and lead author of this study says. “That puts pressure on cells to efficiently scan the DNA and do something about it. That’s what we think the transcription machinery is doing.”

RNA polymerase II is the main enzyme involved in transcription, the process of reading the genetic code. The U-M team did a series of experiments to find out what happens when transcription is blocked. They found that using transcription-blocking agents such as ultraviolet light resulted in activation of the p53 stress response, independent of other cell processes. When they micro-injected an anti-RNA polymerase agent into human cell nuclei, they found that p53 proteins then accumulated in the cell nucleus — one aspect of the stress response — even when no DNA damage occurred. Ljungman and his colleagues also discovered what happens when RNA polymerase II gets stuck on a kink or other lesion in the DNA. It sends a signal via two proteins that activate p53.

“These two proteins are saying, ‘Transcription has stopped,’” says Ljungman. These early triggers act like the citizen who smells smoke and sounds a fire alarm, alerting the fire department. Then p53, like a team of fire fighters, arrives and evaluates what to do. To reduce the chance of harmful mutations that may result from DNA damage, p53 may kill cells or stop them temporarily from dividing, so that there is time for DNA repair.

Published July 31, 2007 in Proceedings of the National Academy of Sciences (PNAS).

UCSD Scientists Studying How Knots Form.

Electrical cables, garden hoses and strands of holiday lights seem to get themselves hopelessly tangled with no help at all. Now research initiated by an undergraduate student at the University of California, San Diego has resulted in the first model of how knots form.

The study, published this week in the journal Proceedings of the National Academy of Sciences, investigated the likelihood of knot formation and the types of knots formed in a tumbled string. The researchers say they were interested in the problem because it has many applications, including to the biophysics research questions their group usually studies.

“Knot formation is important in many fields,” said Douglas Smith, an assistant professor of physics who was the senior author on the paper. “For example, knots often form in DNA, which is a long string-like molecule. Cells have enzymes that undo the knots by cutting the DNA strands so that they can pass through each other. Certain anti-cancer drugs stop tumor cells from dividing by blocking the unknotting of DNA.”

A experiment was set up consisting of a plastic box spun by a computer-controlled motor. A piece of string was dropped into the box and tumbled around like clothes in a dryer. Knots formed very quickly, within 10 seconds. The researchers repeated the experiment more than 3,000 times varying the length and stiffness of string, box size and speed of rotation. Then they classified the resulting knots.

“It is virtually impossible to distinguish different knots just by looking at them,” said Raymer. “So I developed a computer program to do it. The computer program counts each crossing of the string." The published paper cites other researchers who have proposed a similar effect to explain why knotting of the umbilical cord of fetuses is relatively rare, occurring only about one percent of the time.

Published October 4, 2007 in Proceedings of the National Academy of Sciences (PNAS).
THURSDAY - October 4, 2007----------------------------------------News Archive/Return to Today's News Alerts

Less Weight Gain in Pregnancy Suggested for Obese Women.

Many pregnant obese women should gain less weight than currently recommended and women who are severely obese should actually lose weight during pregnancy, researchers here said.

Women with a prepregnancy body mass index of 30 to 34.9 kg/m2 should gain no more than 10 to 25 pounds during pregnancy to minimize the risk of preeclampsia, Caesarean delivery, and an infant who's large or small for gestational age, according to the findings of a cohort study in the October issue of the journal Obstetrics & Gynecology.

However, women with a BMI of 35 to 39.9 kg/m2 should gain no more than 9 pounds and women with a BMI of 40 kg/m2 or more should lose up to 9 pounds to achieve the best outcomes, reported Raul Artal, M.D., of Saint Louis University, and colleagues. Current Institute of Medicine (IOM) guidelines for obese women advise weight gain of at least 15 pounds without an upper limit or distinguishing between levels of obesity. Reevaluating these guidelines, the researchers said, could have important clinical and public health implications because of the increasing prevalence of obesity among women of childbearing age, the tendency for weight retention after birth, and the high prevalence of perinatal complications with obesity.

The authors noted that the study "shows only statistical associations and does not imply causality. The latter can only be achieved by conducting a prospective randomized controlled trial of obese women to determine the effect of
controlled gestational weight gain on specific pregnancy outcomes."

Published October, 2007 in Obstetrics & Gynecology.

Breast Milk Boosts Brain Development in Preemies.

Even extremely low birth weight premature babies should be given breast milk while they are in a hospital's intensive care unit because it appears to boost their mental development, concludes a study in the journal Pediatrics. The study found that preemies fed breast milk had greater mental
development scores at 30 months of age than infants who were not fed breast milk.

“The study involved 773 U.S. babies born extremely underweight - less than 2.2 pounds (1 kg) - between 1999 and 2002. The children were divided into five groups by the quantity of breast milk they ingested while in the NICU. The majority of the infants had been given at least some breast milk while in the NICU administered by a feeding tube that dripped the breast milk into their stomachs; 593 ingested some breast milk, while 180 ingested none. Both groups experienced the same amount of physical growth. But the babies given breast milk got higher scores on a test measuring their overall intelligence at 30 months of age, with the highest scores showing up among the children who had received the most breast milk as infants.

These findings strongly suggest that, whenever possible, preterm infants should routinely be given breast milk during their stay in the intensive care unit," said Dr. Duane Alexander, director of the National Institute of Child Health and Human Development, which backed the study. Previous studies have found that infants who ingest breast milk are able to leave the neonatal intensive care unit sooner than infants receiving formula.

The Canadian Paediatric Society recommends that children be breastfed exclusively for at least six months.

Published October, 2007 in Pediatrics.

Stem Cells 'Prompt Cancer Spread' - But May Be Reversable.

Dangerous changes in cancer cells which allow them to spread around the body could be triggered by the body's own stem cells, say Whitehead Institute scientists. A team found human breast cancers in mice are more likely to spread if mixed with stem cells from the bone marrow. They believe these changes could be blocked or reversed - making the cancer less deadly.

It appears the presence of the stem cells produces genetic changes in the cancer cells that make them metastasise - but once the cells spread, they change back to their original genetic state. This, the researchers say, not only makes these key genes hard to spot, but means that dangerous changes in cancer cells are potentially reversible.

"Although these results don't tell us if exactly the same situation is present in cancers within humans - as they have been done using mice - it's a good indicator that these stem cells may play a role in breast cancer, and could point towards targets for future treatments." Published October 4, 2007 in Nature.



WEDNESDAY - October 3, 2007----------------------------------------News Archive/Return to Today's News Alerts

Residual Fetal Cells in Women Both Detrimental and Beneficial.

Fetal cells that persist in a woman's body long after pregnancy - a common occurrence known in scientific circles as fetal microchimerism - in some cases may reduce the woman's risk of breast cancer, according to researchers at Fred Hutchinson Cancer Research Center. The findings add to the Jekyll and Hyde characteristics of fetal microchimerism, or FMc, which has been found to be both detrimental and beneficial to women's health.

In this latest prospective study, scientists V.K. Gadi, M.D., Ph.D. and J. Lee Nelson, M.D., of the Hutchinson Center's Clinical Research Division, examined the blood of 82 women post-pregnancy, 35 of whom had had breast cancer. They looked for male DNA in the blood, presuming it was present due to a prior pregnancy. Fetal microchimerism (FMc) was found significantly more often in healthy women than women with a history of breast cancer, 43 percent versus 14 percent respectively. The scientists concluded that FMc may contribute to reduction of breast cancer based on the hypothesis that residual fetal cells may provide immune surveillance of malignant cells in the mother. They caution that further studies are needed to confirm the theory.

Prior research into FMc, some of it performed at the Hutchinson Center, indicates that while the presence of fetal cells in women may confer immune protection and promote cell repair, such cells also may be harbingers of some autoimmune diseases. It is well established that women who have given birth have a lower risk of breast cancer. And, allogeneic (from another individual) stem-cell transplants are used to treat many types of blood cancers by replacing a diseased immune system with a healthy one.

Additionally, fetal cells are commonly found in the circulating blood of healthy women who have given birth. Fetal cells represent a naturally acquired source of allogeneic immune cells; in prior studies the prevalence of T, B, natural-killer (NK) and antigen-presenting cells of fetal origin in healthy women ranged from 30 percent to 70 percent, depending on the cell type. Published October 1, 2007 in Cancer Research.


Study Fuels Debate - Do Exercise & Body Size Influence Ovarian Cancer Risk.

The study, presented by Australian researchers at the European Cancer Conference (ECCO 14) in Barcelona, found some evidence suggesting exercise might increase the risk of ovarian cancer; however, it found no link with body size.

The study included 24,479 Australian women aged between 27 and 75, followed for an average of 13 years. Body measurements such as waist circumference, weight, fat mass and non-fat mass were taken and the women were questioned about the frequency and intensity of their physical activity outside of work. Those answers were combined into a formula to score physical activity levels. During the study, 90 of the women were diagnosed with ovarian cancer. Thirteen of those women did no exercise, 21 reported low levels of physical activity, 37 reported medium levels and 19 were classified as engaging in high levels of physical activity.

“Two strengths of our study were that while most other studies of this type have used self-reported weight and height to calculate BMI, we directly measured these in all of our participants. Unlike most other studies, we also directly measured fat mass,” Chionh said. “This approach makes the measurements more reliable.”

Some studies have shown that higher levels of physical activity are linked with decreased oestrogen levels in women. This may trigger the pituitary gland to release more gonadotropin hormones, which have been theorised to lead to possible development of ovarian cancer by stimulating oestrogen or oestrogen precursors that cause excessive proliferation of ovarian cells.

Another study has shown that higher levels of physical activity are linked with increased androgen levels, which have also been hypothesised to play a role in ovarian cancer development.

A third hypothesis is linked with a study showing that higher levels of vigorous exercise lead to an increased frequency of ovulation. Scientists have hypothesised that after each ovulation, there is a proliferation and repair of ovarian cells, which leads to recurrent minor trauma. Therefore, with more ovulatory cycles, there is an increased risk of developing ovarian cancer. Presented September 27 , 2007 at the Ecco 14 conference, Barcelona, Spain.


Testing Women for Group B Strep During Pregnancy.

A research paper confirms what medical charity Group B Strep Support has been saying for years - that testing pregnant women for group B strep would save lives and save the government money. The article in the British Medical Journal reports that most group B Streptococcal (GBS) infection in newborn babies could be prevented by changing current best practices. The report found that offering testing for group B Strep to all pregnant women was the most cost effective option, with antibiotics being offered in labor when it is found.

Group B Strep causes infections such as meningitis, septicaemia and pneumonia. It affects 700 babies every year in the UK, killing 75 and leaving 40 with serious long-term mental or physical problems. GBS infection can usually be prevented by giving antibiotics during labor to women whose babies are most at risk of developing these infections.

Jane Plumb adds: 'We need to offer women testing for group B Strep late in pregnancy and, if GBS is found, then they need to decide with their health professionals, what action if any to take in labor''.

Published October 1, 2007 in Best Treatments BMJ.

Physical Exercise During Pregnancy and the Risk of Miscarriage.

According to a recent study carried out in Denmark women who exercise intensively during the first phase of pregnancy are 3.7 times more likely to miscarry. The researchers say the women most at risk are those who do high impact exercise such as jogging and racketball but women who exercise strenuously for at least seven hours a week during the first trimester of pregnancy run the highest risk..

After the 18th week of pregnancy the risk almost completely disappeared.

The researchers say there was no increased danger of miscarriage to women who swam during any phase of pregnancy. The study was based on interviews with 92,671 pregnant women in Denmark which were analysed by Anne Marie Nybo Andersen and colleagues from the University of Southern Denmark.

The researchers however do also say that expectant mothers should not be discouraged from taking mild to moderate exercise, but suggest their findings indicate the need for a review of exercise guidelines for pregnant women.

Published in the September 2007 issue of the journal BJOG: An International Journal of Obstetrics and Gynaecology.

Low Maternal Cholesterol a Risk for Preterm Birth.

"Total serum cholesterol below the 10th percentile in the second trimester was the strongest predictor of preterm delivery in low-risk mothers, reports Maximilian Muenke, M.D., of the National Human Genome Research Institute of the National Institutes of Health, and colleagues. This association was almost entirely among white women with no significant effect noticed among black women.

No studies have previously looked at a lower boundary for cholesterol in pregnancy. So, a retrospective study was done of 118 women with total cholesterol below the 10th percentile (159 mg/dL at a mean gestational age 17.6 weeks) and 940 women with higher total cholesterol; only nonsmoking women ages 21 to 34 without diabetes who gave birth to a single, live infant were included.

Although this pilot study included a highly selected population and requires validation, "the consistent finding that low maternal serum cholesterol was the strongest predictor of preterm delivery in every model tested" supports the association between low cholesterol and risk of preterm birth, said Dr. Muenke. Published October, 2007 in Pediatrics.

TUESDAY - October 2, 2007----------------------------------------News Archive/Return to Today's News Alerts

Computer Simulation Shows How Proteins Vibrate In a Crystal.
Understanding how proteins - life's worker molecules - interact with each other is a major goal of biological sciences. Now, an international collaboration directed by an Oak Ridge National Laboratory (ORNL) researcher has performed the first-ever atomic-detail computer simulation of how proteins vibrate in a crystal.


Jeremy Smith, who leads ORNL's Center for Molecular Biophysics, said experimental testing of the theoretical work will require the capabilities of the Office of Science's recently completed Spallation Neutron Source at ORNL. Phonon dispersion relations provide information on how proteins interact with each other. That could be useful for understanding protein-protein interactions in the living cell. Until now, researchers have lacked the computing power to allow atomic-detail lattice dynamical calculations.

"Atomic-detail crystal dynamics calculations have not been possible before, and now we also have an experimental tool--the SNS--that will have the capability to test our simulations. We are looking forward to seeing the next generation of instruments at SNS demonstrate their talents." Smith said, humbly adding, "Hopefully, the calculations won't be too painfully off the mark."

Smith believes the SNS and its arsenal of specialized analytical instruments will be able to confirm - or contradict - what the simulations indicate. Published October 2, 2007 on website of the Oak Ridge National Laboratory.

The Cell Size Problem.
How does a cell know when it is big enough to divide? For more than 100 years, scientists have tried to figure this out.

In research conducted in budding yeast (Saccharomyces cerevisiae), scientists at Rockefeller University have now identified the cellular event that marks the moment when a cell knows it is big enough to commit to cell division and spawn genetic replicas of itself. The findings, reported in the Aug. 23 issue of the journal Nature , provide a precise and quantitative framework for studying the possible mechanisms that allow cells to monitor and sense their size.

During the first phase of the cell cycle, known as G1, yeast cells grow and begin to form a bud; in the final stage, the cell splits into two - one bigger than the other. Although researchers have identified several key proteins coordinating cell growth and division during G1, they hadn't identified the core mechanism that senses whether a cell possesses enough resources to divide. Scientists needed a way to organize and sort molecular candidates involved in cell size control from those that played other roles.

Graduate student Stefano Di Talia, a biophysicist, and postdoc Jan Skotheim, an applied mathematician, provided the tools. Working with Eric Siggia, head of the Laboratory of Theoretical Condensed Matter Physics, and Fred Cross, head of the Laboratory of Yeast Molecular Genetics, Di Talia and Skotheim showed that a unique cellular event - the exiting of the protein Whi5 from the nucleus - separates G1 into two independent steps: one controlled by a sizer (T1) and one controlled by a timer (T2). T1 begins when the mother and daughter cells have completely separated from each other; T2 starts in G1 once Whi5 has exited the nucleus and lasts until the new daughter cell forms its own bud.

By measuring the sizes of budding yeast and how long they spend in G1 and in T1, Di Talia saw that daughter cells are much smaller than their mother cells and need to spend more time in T1 growing. Once daughter cells reach the required size for division, they spend as much time as their mothers in T2, replicating their DNA and producing daughter cells of their own.

Di Talia and his colleagues used genetics to identify a medley of proteins that coordinate cell growth and division during T1 and T2 - a crucial finding highlighting that the two parts of G1 as independent from each other and regulated differently. "If we continue to identify the molecular events that change how T1 is regulated," says Di Talia, "we can really hope to get to the core of what the size-sensing machinery is." Published August 23, 2007 in the journal Nature.

Origins of Mammalian Lymphatic Vasculature.
Understanding the development of the lymphatic vasculature system is integral to understanding its function in both health (mediating immunity and maintaining tissue fluid levels) and disease (lymphedema and spreading tumor metastasis).

Dr. Guillermo Oliver of St. Jude Children's Research Hospital and colleagues now present evidence resolving this century-old debate. The adult mammalian lymphatic vasculature is derived from a few embryonic lymph sacs. The debate surrounding the cellular origin of the lymphatic vasculature was: Does it arise from venous endothelial cells or does it arise in the mesenchyme and then establish venous connection later on in development"

Dr. Oliver used genetically modified mice to perform elegant lineage tracing experiments that established the mammalian lymphatic vasculature is venous-derived. Published October 1, 2007 in Genes & Development (G&D).

Bilingual Babies Learn New Words Differently.
Infants who are raised in bilingual homes learned two similar-sounding words in a laboratory task at a later age than babies who are raised in homes where only one language is spoken.

This difference, which is thought to be advantageous for bilingual infants, appears to be due to the fact that bilingual babies need to devote their attention to the general associations between words and objects (often a word in each language) for a longer period, rather than focusing on detailed sound information. This finding suggests an important difference in the mechanics of how monolingual and bilingual babies learn language.

These findings are from new research conducted at the University of British Columbia and Ottawa. Published in the September/October 2007 issue of the journal Child Development.

Stem Cells Secrete Healing Chemicals.
Many stem-cell researchers hope to treat diseases by recruiting adaptable stem cells to replace others that have been damaged. Now a report demonstrates a different approach, which rescued mice that otherwise would have died from a genetic heart defect before birth. Instead of replacing the defective cells, embryonic stem (ES) cells released chemical signals that caused the defective heart tissue to grow properly.

"Mouse embryos that lack multiple Id proteins die before birth because the wall of the heart is too thin. To buy themselves more time to study the blood vessels, the researchers injected 15 normal ES cells into early mouse embryos. About half of the embryos actually survived past birth, and exhibited normal-looking hearts. "It came as a complete shock to us that they were born." said Robert Benezra of the Memorial Sloan-Kettering Cancer Center.

Descendants of the injected ES cells accounted for just one in five cells in the rescued hearts, so the injected cells had not simply taken over. Instead, the researchers determined, exposure to two chemicals secreted by the ES cells prompted the defective cells to start producing different set of proteins and develop properly. One of these chemicals even reached the embryo across the placenta from ES cells injected earlier into the mother.

Exploiting the signaling molecules secreted by ES cells, rather than the cells themselves, may someday form the basis for new treatment. For example, molecules might be used directly, or the ES cells might be employed to deliver these healing chemicals to where they are needed. Still, "The first challenge is to see how general this is," Benezra cautions. In a commentary accompanying the Science report, Kenneth Chien, Alessandra Moretti and Karl-Ludwig Laugwitz suggest that other stem-cell researchers should make certain to check whether their results arise from the cells themselves, or from chemicals the cells may be secreting. This new finding, Chien remarks, is "one of the most exciting discoveries in the field of cardiac stem cells to date." Published September, 2007 in the Science.

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