News 26 march 2009
Vitamin B and Folic Acid
Supplements Prevent Migraines
Increased intake of folic acid and other B
vitamins may reduce the frequency and severity of migraine attacks, according to a study
conducted by researchers from the Genomics Research Center at Australia's Griffith
University.
URI scientists reveal mechanism
that regulates cancer-causing gene
Two University of Rhode Island scientists
have revealed how a cancer causing protein is regulated by reactive oxygen species (ROS)
-- a type of stress signal. Their findings provide new insight into how this protein
normally behaves in human cells and may help in the design of drugs targeting specific
cancers. Doctoral student David J. Kemble and Professor Gongqin Sun in the URI Department
of Cell and Molecular Biology are the first to provide a biochemical mechanism describing
how certain protein tyrosine kinases sense and respond to oxidation. This sensing system
was found to uniquely apply to two families of proteins implicated in numerous cancers:
the Src and Fibroblast Growth Factor Receptor families of tyrosine kinases. Their results
were published online March 9 in the Proceedings of the National Academy of Sciences. Src
was the first enzyme identified as a cancer-causing gene in the early 1900's. For years
scientists have been studying how the enzymes are expressed in cancer cells – what do
they do and what controls them. According to Kemble and Sun, Src is a master regulator of
cell function, controlling cell metabolism, division, and death. In normal cells, the
function of Src is turned off, and it is turned on only when certain stimulatory signals
activate it. When the regulatory mechanisms that control Src activity are disrupted, Src
may be turned on all the time, which turns the host cell into a cancer cell. Thus, it is
crucial to understand how Src function is controlled.
Hormone-mimics in plastic water
bottles - just the tip of the iceberg?
Plastic packaging is not without its
downsides, and if you thought mineral water was ‘clean’, it may be time to think
again. According to Martin Wagner and Jörg Oehlmann from the Department of Aquatic
Ecotoxicology at the Goethe University in Frankfurt am Main, Germany, plastic mineral
water bottles contaminate drinking water with estrogenic chemicals. In an analysis1 of
commercially available mineral waters, the researchers found evidence of estrogenic
compounds leaching out of the plastic packaging into the water. What’s more, these
chemicals are potent in vivo and result in an increased development of embryos in the New
Zealand mud snail. These findings, which show for the first time that substances leaching
out of plastic food packaging materials act as functional estrogens, are published in
Springer’s journal Environmental Science and Pollution Research.
Questioning Why Healthcare
Information Technology Manufacturers Are Free of All Liability When Their Products Can
Result in Medical Errors
Even when their products are implicated in
harm to patients, manufacturers of healthcare information technology (HIT) currently enjoy
wide contractual and legal protection that renders them virtually
“liability-free,” writes Ross Koppel, Ph.D., of the University of Pennsylvania
School of Medicine, in the March 25th issue of the Journal of the American Medical
Association. The current system needs to be changed so that all liability does not rest
entirely with physicians, nurses, hospitals, and clinics, even when these users of faulty
HIT scrupulously follow vendor instructions, according to Dr. Koppel’s piece,
co-authored with David Kreda, a software designer. The HIT industry avoids liability by
relying on a legal doctrine known as “learned intermediaries” that holds
physicians, nurses, pharmacists, and healthcare technicians responsible for HIT errors
because are presumed to be able to identify—and correct— medical mistakes
generated by software faults. “HIT vendors claim that, because they cannot practice
medicine, clinicians should be accountable for identifying errors resulting from faulty
software or hardware,” said Koppel. “But errors or lack of clarity in HIT
software can create serious, even deadly, risks to patients that clinicians cannot
foresee.”
Missing or mutated
"clock" gene linked to vascular disease
The circadian clocks that set the rhythmic
motion of our bodies for wakeful days and sleepy nights can also set us up for vascular
disease when broken, Medical College of Georgia researchers say. Mice with mutated or
missing "clock" genes are prone to thick, inflexible blood vessels with narrow
passageways, unhealthy changes typically associated with risk factors such as smoking,
high blood pressure and cholesterol, according to research in this week's issue of
Circulation. "Having a bad or broken clock seems to promote vascular disease,"
says Dr. Daniel Rudic, vascular biologist in the MCG Schools of Medicine and Graduate
Studies and the study's corresponding author.
Changes in gene may stunt lung
development in children
Mutations in a gene may cause poor lung
development in children, making them more vulnerable to diseases such as chronic
obstructive pulmonary disease (COPD) later in life, say researchers at the University of
Pittsburgh Graduate School of Public Health and the German Research Center for
Environmental Health. Their study, published online in Physiological Genomics, measured
expression levels of the gene and its variants in both mouse lungs and children ages 9 to
11. Study authors, led by George Leikauf, Ph.D., professor of occupational and
environmental health at the University of Pittsburgh Graduate School of Public Health, and
Holger Schulz, M.D., professor of medicine at the Institute of Lung Biology and Disease,
German Research Center for Environmental Health, Munich, focused on a gene called
superoxide dismutase 3 (SOD3), previously shown to protect the lungs from the effects of
asbestos and oxidative stress. "People lose lung function as they age, so it's
important to identify possible genetic targets that control healthy development of the
lungs during childhood," said Dr. Leikauf. Drs. Leikauf, Schulz and colleagues
compared SOD3 expression levels in strains of mice with poor lung function to one with
more efficient airways and lungs two times the size. As with people, the lungs of mice
fully form as they mature to adulthood. The better-functioning strain maintained higher
levels of SOD3 – levels in these mice were four times higher at the final stage of
lung development. They also found the presence of single nucleotide polymorphisms, or
SNPs, variations in DNA sequences, in SOD3 that were linked to lung function in mice.
DNA repair mechanisms relocate in
response to stress
Like doctors making house calls, some DNA
repair enzymes can relocate to the part of the cell that needs their help, a collaborative
team of scientists at Emory University School of Medicine has found. The signal that
prompts relocation is oxidative stress, an imbalance of cellular metabolism connected with
several human diseases. The study integrated the expertise of three Emory groups and
resulted in a new level of understanding of the cell's response to genetic damage. The
finding could lead to new targets for anti-cancer drugs that interfere with DNA repair,
says Paul Doetsch, PhD, professor of biochemistry, radiation oncology, and hematology and
oncology at Emory University School of Medicine. The results were published in the
February 1 issue of Molecular and Cellular Biology. The journal's editors chose an image
of yeast cells with fluorescent DNA repair enzymes for the cover. "DNA damage and
oxidative stress are very closely related," Doetsch says. "For example, the way
radiation inflicts most of its damage on DNA is through oxidative stress. The more we know
about how cells respond to oxidative stress, the more chances there could be to influence
those responses for diagnostic or therapeutic purposes." The DNA inside cells is
continually under assault by heat, radiation and oxygen. Cells have an extensive set of
repair enzymes that comb through DNA, continually excising and re-copying damaged
segments. To complicate matters, mitochondria (cells' miniature power plants) have their
own DNA.
New Study Finds Financial Advice
Causes "Off-Loading" in the Brain
A study using functional magnetic resonance
imaging (fMRI) shows that expert advice may shut down areas of the brain responsible for
decision-making processes, particularly when individuals are trying to evaluate a
situation where risk is involved. The study was published in the March 2009 issue of the
Public Library of Science (PLOS One). During times of uncertainty such as an economic
recession, many people feel unqualified to sort out the implications of their financial
decisions. Often they will seek the advice of a consultant on what choices to make. In a
study led by Gregory Berns, MD, PhD, professor of neuroeconomics and psychiatry at Emory
University School of Medicine, researchers investigated the neural mechanisms through
which advice is integrated into the financial decision making process. "While the
field of neuroeconomics has made progress in understanding the neurobiological basis of
risky decision-making, the neural mechanisms through which external information is
integrated in that process had not been studied before this," says Berns.
Gene variants may determine lung
function and susceptibility to maternal smoking
A tiny variation within a single gene can
determine not only how quickly and well lungs grow and function in children and
adolescents, but how susceptible those children will be to exposure to second-hand tobacco
smoke, even in utero, according to researchers from the University of Southern California.
"Many factors can affect lung function and growth, including genetic variation and
environmental exposures such as tobacco smoke and air pollutants," said Carrie
Breton, Sc.D., lead author of the study conducted at the University of Southern
California. "We wanted to determine whether specific gene variations would have
measurable and predictable effects on lung function growth and susceptibility to
environmental insults. We looked at a class of genes known to be involved in antioxidant
defense, the glutathione-s transferase (GST) genes. Overall, we found that variation in
several of the GST genes was important. This was particularly true for children of mothers
who had smoked during pregnancy." The researchers analyzed eight years' worth of lung
function metrics and genotyping data from more than 2,100 children from two cohorts of
fourth-graders. The lung function measurements used were maximal mid expiratory flow rate
(MMEF), forced vital capacity (FVC) and forced expiratory volume in one second (FEV1).
"FEV1 is a measure of large airways, FVC of total lung volume and MMEF of smaller
airways, so they measure slightly different things and we wouldn't necessarily expect to
see all outcomes behaving the same," said Dr. Breton. They found that for three of
the specific haplotypes (patterns of genetic variation within genes) they investigated,
each had a significant effect on lung function.
Nutritious new low-sugar juice
targeted for diabetics, individuals with high blood sugar
Scientists in China are reporting
development of a low-calorie, low-sugar vegetable juice custom-designed for millions of
individuals with diabetes and pre-diabetic conditions that involve abnormally high blood
sugar. They reported on the new drink here at the 237th National Meeting of the American
Chemical Society. Heqin Xing, Ph.D., and Xiuqi Liu of Jilin University in Changchun,
China, described a cost-effective method of preparing a special type of vegetable drink
using lactic acid-producing bacteria (LAB) to remove carbohydrates while retaining good
taste, vitamins and other nutrients. "This is an exciting development," Liu
said. "The process significantly removes sugar but retains the nutritional content of
the juice's raw materials." To develop the juice — made from pumpkin, balsam
pear, onion and carrots — Xing and Liu turned to an age-old technique in the art of
food production. For thousands of years, people have cultured food — including
everyday eats such as yogurt, cheeses and sausage — by using the same LAB.LAB
microbes produce a compound commonly found in sour milk products called lactic acid.
Because of LAB's healthy link to food production, this class of bacteria is also referred
to as probiotics. In the study, LAB reduced sugar content of the vegetable juice by
transforming carbohydrates into lactic acid by a routine conversion process called
fermentation. As this process increases the juice's acidity, it extends its shelf life as
it inhibits growth of other bacteria. Compared to other microorganisms, LAB are known for
their ability to withstand acidic environments. In addition to the lactic acid's
protection against contamination, the acidity from fermentation could enhance flavors in
the beverage.
EPA new strategic plan for
evaluating the toxicity of chemicals
EPA is releasing a new approach to advance
the science upon which the agency bases its regulatory decisions and policies, resulting
in better protection for human health and the environment. Today, EPA released the
"U.S. Environmental Protection Agency's Strategic Plan for Evaluating the Toxicity of
Chemicals." This strategic plan outlines a new scientific approach that will allow
EPA to assess risks from many chemicals and mixtures by adopting new toxicity testing
methods that use recent advances in molecular biology, genomics, and computational
sciences. When fully implemented, EPA will be able to screen thousands of environmental
chemicals quickly for potentially harmful effects. The strategic plan will also allow EPA
scientists to look at how children may react differently to the same chemicals as adults,
thus providing better health protection for children.
Bad news for insomniacs - 'hunger
hormones' affected by poor sleep
Insomnia has long been associated with poor
health, including weight gain and even obesity. Now researchers at UCLA have found out
why. In a study to be published in the May issue of the journal Psychoneuroendocrinology
and currently available online by subscription, Sarosh Motivala, an assistant professor of
psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, and
colleagues looked at two hormones that are primarily responsible for regulating the body's
energy balance, telling the body when it is hungry and when it is full. The study found
that chronic insomnia disrupts one of these two hormones. To date, no study has evaluated
nocturnal levels of the two hormones, ghrelin and leptin, in primary insomnia patients.
Ghrelin, a peptide secreted by the stomach, stimulates appetite and increases before
meals. Leptin, which affects body weight and is secreted primarily by fat cells, signals
the hypothalamus regarding the degree of fat storage in the body; decreased leptin tells
the body there is a calorie shortage and promotes hunger, while increased levels promote
energy expenditure. In the study, researchers compared healthy sleepers with those
suffering from chronic insomnia and measured the levels of the two hormones at various
times throughout the night. They found that while leptin levels averaged out over the
night to be roughly the same between the two groups, levels of ghrelin were 30 percent
lower in insomnia sufferers. On the face of it, a decreased level of ghrelin would seem to
inhibit weight gain; it is an increase in ghrelin, after all, that stimulates appetite.
But Motivala compared his findings with other, earlier studies on sleep deprivation and
speculates that a switch may occur during the day: Sleep loss leads to increased ghrelin
and decreased leptin, a "double whammy" that stimulates appetite. Motivala is
currently working on a study to examine this switch.
