News 30 juli 2009
U of T team helps to
"barcode" the world's plants
An international team of scientists, including botanists from the University of Toronto,
have identified a pair of genes which can be used to catalogue the world's plants using a
technique known as DNA barcoding — a rapid and automated classification method that
uses a short genetic marker in an organism's DNA to identify it as belonging to a
particular species. "Barcoding provides an efficient means by which we can discover
the many undescribed species that exist on earth," says Spencer Barrett, a professor
of ecology and evolutionary biology at the University of Toronto and the head of the
Canadian plant barcoding working group. "This discovery is important because
understanding biodiversity is crucial to long-term human existence on the planet."
DNA barcoding has been widely used to identify animal species since its invention five
years ago. But its use for plants was delayed because of the complex nature of plant
genetics and disagreements over the appropriate DNA regions to use.
Study finds significant number of
kids experience family homelessness
A new multisite study by UCLA and RAND Corp. researchers and colleagues has found that 7
percent of fifth-graders and their families have experienced homelessness at some point in
their lives and that the occurrence is even higher — 11 percent — for African
American children and those from the poorest households. The study also found that
children who had experienced homelessness at some point during their lives were
significantly more likely to have an emotional, behavioral or developmental problem; were
more likely to have witnessed serious violence with a knife or a gun; and were more likely
to have received mental health care. The research is the first population-based study to
describe the lifetime prevalence of family homelessness among children and its association
with health and health care. The findings will be published in the August issue of the
American Journal of Public Health and are currently available online by subscription.
ISU researchers find possible
treatment for Spinal Muscular Atrophy
Spinal Muscular Atrophy is the second-leading cause of infant mortality in the world.
Ravindra Singh, associate professor in biomedical sciences at Iowa State University's
College of Veterinary Medicine, would like to see Spinal Muscular Atrophy lose its high
ranking and even slide off the list altogether. Most Spinal Muscular Atrophy sufferers --
more than 95 percent -- have a mutated or deleted gene called Survival Motor Neuron 1
(SMN1) that doesn't correctly do its job of creating functional SMN proteins. Singh's
solution is to replace that poor-performing gene with another gene. Humans need a certain
level of SMN protein to ward off Spinal Muscular Atrophy. When SMN1 fails to create
functioning proteins, Spinal Muscular Atrophy is the result.
Researchers Develop
“Brain-Reading” Methods To Uncover A Person’s Mental State
It is widely known that the brain perceives information before it reaches a person’s
awareness. But until now, there was little way to determine what specific mental tasks
were taking place prior to the point of conscious awareness. That has changed with the
findings of scientists at Rutgers University in Newark and the University of California,
Los Angeles who have developed a highly accurate way to peer into the brain to uncover a
person’s mental state and what sort of information is being processed before it
reaches awareness. With this new window into the brain, scientists now also are provided
with the means of developing a more accurate model of the inner functions of the brain. As
reported in a forthcoming (Oct. 2009) issue of Psychological Science, the findings
obtained by Stephen José Hanson, psychology professor at Rutgers; Russell A. Poldrack,
professor at UCLA, and Yaroslav Halchenko, (now a post-doctoral student at Dartmouth
College), have provided direct evidence that a person’s mental state can be predicted
with a high degree of accuracy through functional magnetic resonance imaging (fMRI). The
research also suggests that a more comprehensive approach is needed for mapping brain
activity and that the widely held belief that localized areas of the brain are responsible
for specific mental functions is misleading and incorrect. The research was funded with
grants from the U.S. Office of Naval Research, the James S. McDonnell Foundation and
National Science Foundation. The McDonnell Foundation recently awarded Hanson another $1
million for ongoing studies in this area.
Molecule Plays Early Role In
Nonsmoking Lung Cancer
The cause of lung cancer in never-smokers is poorly understood, but a study led by
investigators at the Ohio State University Comprehensive Cancer Center and at the National
Cancer Institute has identified a molecule believed to play an early and important role in
its development. The findings, published online recently in the Proceedings of the
National Academy of Sciences, may lead to improved therapy for lung cancer in both
never-smokers and smokers, including those with tumors resistant to targeted drugs such as
gefitinib. The study examined lung tumors from people who had never smoked and found high
levels of a molecule called miR-21. The levels were even higher in tumors that had
mutations in a gene called EGFR, a common feature of lung cancer in never-smokers.
“Several important lung cancer drugs target EGFR mutations, but these agents are
ineffective in about 30 percent of cases in which the mutation is present,” says
co-principal investigator Dr. Carlo M. Croce, professor of molecular virology, immunology
and medical genetics at the Ohio State University Comprehensive Cancer Center - James
Cancer Hospital and Solove Research Institute. “Our study suggests that developing
agents to inhibit miR-21 might improve these anti-EGFR therapies.”
Maternal, paternal genes'
tug-of-war may last well into childhood
An analysis of rare genetic disorders in which children lack some genes from one parent
suggests that maternal and paternal genes engage in a subtle tug-of-war well into
childhood, and possibly as late as the onset of puberty.This striking new variety of
intra-family conflict, described this week in the Proceedings of the National Academy of
Sciences, is the latest wrinkle in the two-decades-old theory known as genomic imprinting,
which holds that each parent contributes genes that seek to nudge his or her children's
development in a direction most favorable, and least costly, to that parent.
"Compared to other primates, human babies are weaned quite early, yet take a very
long time to reach full nutritional independence and sexual maturity," says author
David Haig, George Putnam Professor of Organismic and Evolutionary Biology in Harvard
University's Faculty of Arts and Sciences. "Human mothers are also unusual among
primates in that they often care for more than one child at a time. Evidence from
disorders of genomic imprinting suggests that maternal and paternal genes may skirmish
over the pace of human development." Previous research has offered evidence of a
genetic struggle for supremacy only during fetal development: In the womb, some genes of
paternal origin have been shown to promote increased demands on mothers, leading to fetal
overgrowth, while genes of maternal origin tend to have the opposite effect. This new work
suggests maternal and paternal genes continue to engage in internal genetic conflict past
childbirth. "This analysis suggests that human life history, and especially humans'
unusual extended childhood, may reflect a compromise between what's best for mothers,
fathers, and the offspring themselves," Haig says.
Common household pesticides linked
to childhood cancer cases in Washington area
A new study by researchers at the Georgetown's Lombardi Comprehensive Cancer Center finds
a higher level of common household pesticides in the urine of children with acute
lymphoblastic leukemia (ALL), a cancer that develops most commonly between three and seven
years of age. The findings are published in the August issue of the journal Therapeutic
Drug Monitoring. Researchers caution that these findings should not be seen as
cause-and-effect, only that the study suggests an association between pesticide exposure
and development of childhood ALL. "In our study, we compared urine samples from
children with ALL and their mothers with healthy children and their moms. We found
elevated levels of common household pesticides more often in the mother-child pairs
affected by cancer," says the study's lead investigator, Offie Soldin, PhD, an
epidemiologist at Lombardi. Soldin cautions, "We shouldn't assume that pesticides
caused these cancers, but our findings certainly support the need for more robust research
in this area." The study was conducted between January 2005 and January 2008 with
volunteer participants from Lombardi and Children's National Medical Center who live in
the Washington metropolitan area. It included 41 pairs of children with ALL and their
mothers (cases), and 41 pairs of healthy children and their mothers (controls). For
comparison purposes, the case pairs were matched with control pairs by age, sex and county
of residence. Previous studies in agricultural areas of the country have suggested a
relationship between pesticides and childhood cancers, but researchers say this is the
first study conducted in a large, metropolitan area.
Chicago team uses artificial
intelligence to diagnose metastatic cancer
When doctors are managing care for women with breast cancer, the information available to
them profoundly influences the type of care they recommend. Knowing whether a woman's
cancer has metastasized, for instance, directly affects how her doctors will approach
treatment -- which may in turn influence the outcome of that treatment. Determining
whether a tumor has metastasized is not always straightforward, however. Radiologists
often start by using diagnostic ultrasound to non-invasively probe the nearby lymph nodes
-- tissues where cancer cells first migrate once they metastasize. But in the early stages
of cancer, lymph nodes often appear completely normal even if the cancer has metastasized.
Now a team of researchers at the University of Chicago has designed a computer program
that uses artificial intelligence to analyze the features of ultrasound images in order to
help doctors predict earlier whether a woman's cancer has metastasized. The team will
discuss the first preclinical results obtained using this program at the upcoming meeting
of the American Association of Physicists in Medicine (AAPM), which takes place from July
26 - 30, 2009 in Anaheim, California. Currently there are no automated methods approved by
the Food and Drug Administration for diagnosing cancer, but on Wednesday the team will
report the results of a preliminary pilot study that retrospectively reanalyzed the
diagnostic ultrasounds of 50 women with suspected breast cancer who all had lymph nodes
that appeared normal in the ultrasound -- suggesting that their cancers had not
metastasized.
Stress signals link pre-existing
sickness with susceptibility to bacterial infection
Mitochondrial diseases disrupt the power generating machinery within cells and increase a
person's susceptibility to bacterial infection, particularly in the lungs or respiratory
tract. A new study published in Disease Models & Mechanisms (DMM), shows that
infection with the pneumonia causing bacteria Legionella, is facilitated by an increased
amount of a signaling protein that is associated with mitochondrial disease. Patients with
mitochondrial disease exhibit a wide range of symptoms including diabetes, blindness,
deafness, stroke-like episodes, epilepsy, ataxia, muscle weakness and kidney disease. The
metabolic abnormalities that cause these effects also induce a stress signal intended to
help the body overcome its energy deficit. The stress-signal induces the production of
more mitochondria, the energy generating 'powerplants' of the body, in the hopes that more
mitochondria will result in a better power supply. Researchers now show that the
stress-signal associated with mitochondrial disease facilitates the growth and
reproduction of the lung-infecting bacteria, Legionella. Cells with mitochondrial disease
increase their production of a signaling protein called AMP-activated protein kinase
(AMPK), to promote the generation of more energy producing mitochondria. Infectious
bacteria, like Legionella, target the mitochondria and might use them to supplement their
own needs and survival requirements. By manipulating AMPK levels, scientists were able to
directly influence the ability of bacteria to replicate inside of the single-celled
organism, Dictyostelium.
High calcium level in arteries may
signal serious heart attack risk
Researchers may be able to predict future severe cardiac events in patients with known,
stable coronary artery disease (CAD) using coronary calcium scoring, according to a study
published in the online edition of Radiology."The amount of calcium in the coronary
vessels, as measured by CT, is of high predictive value for subsequent serious or fatal
heart attack in these patients, independent of the patient's age, sex and other coronary
risk factors," said the study's lead author, Marcus Hacker, M.D., resident physician
in the Department of Nuclear Medicine, leader of the research unit for nuclear cardiology
and assistant medical director at Ludwig Maximilians University in Munich, Germany. CAD is
the most common type of heart disease. According to the National Heart, Lung and Blood
Institute, it is the leading cause of death in the U.S. for both men and women, killing
more than 500,000 Americans each year. CAD is a condition in which plaque, consisting of
cholesterol, calcium, fat and other substances, builds up inside the arteries that supply
blood to the heart. When plaque builds up in the coronary arteries, blood flow to the
heart is reduced and may lead to arrhythmia, heart attack or heart failure. Single photon
emission computed tomography (SPECT) myocardial perfusion imaging is a nuclear medicine
diagnostic procedure that provides excellent three-dimensional images of the coronary
arteries to assist in the diagnosis and treatment of CAD. Currently, calcium
scoring—measuring the amount of calcium in the arteries—is used as a screening
exam and in cases of suspected CAD, but not in cases of known CAD.
Discovery to aid in future
treatments of third-world parasites
Schistosomiasis, one of the most important of the neglected tropical diseases, is caused
by infection with parasitic helminths of the genus Schistosoma. These parasites are long
lived (>10 years) and dwell within blood vessels, where they produce eggs that become
the focus of intense, chronic inflammatory responses. In severe cases, this inflammation
is associated with life-threatening liver disease. No vaccine is currently available to
prevent schistosomiasis. Options for treating the disease are largely limited to one drug,
Praziquantel. Rates of re-infection in drug-treated individuals are high, and it is feared
that widespread use may foster the emergence of drug-resistant variants, such as has seen
with drug-resistant strains of tuberculosis. The body's immune response to schistosome
infection, as with all immune responses, is coordinated by cytokines, small proteins
secreted by immune cells. Due to their fundamental importance, cytokine research is a
significant focus of research at the Trudeau Institute. Because cytokines travel through
the body to relay critical information, it is difficult to identify the cells that produce
them and to learn about their role. Trudeau investigators have devised cytokine
"reporter mice" for tracking cells that produce the signature cytokine of the
so-called "Th2" immune response mounted against infections with parasitic worms,
interleukin-4 (IL-4). While it was previously known that the complex mixture of proteins
released by schistosome eggs induce Th2 responses and the production of IL-4, the specific
molecule(s) responsible for these effects were unknown. Research from the laboratories of
Markus Mohrs of the Trudeau Institute and Gabriele Schramm of the Research Centre Borstel
in Germany had previously shown that a protein called alpha-1 can support Th2 responses
but is unable to initiate them.
Placenta-derived stem cells may
help sufferers of lung diseases
An Italian research team, publishing in the current issue of Cell Transplantation (18:4),
which is now available on-line without charge at
http://www.ingentaconnect.com/content/cog/ct, has found that stem cells derived from human
placenta may ultimately play a role in the treatment of lung diseases, such as pulmonary
fibrosis and fibrotic diseases caused by tuberculosis, chemical exposure, radiation or
pathogens. These diseases can ultimately lead to loss of normal lung tissue and organ
failure. No known therapy effectively reverses or stops the fibrotic process.
Placenta-derived stem cells are known to be able to engraft in solid organs, including the
lungs. Human term placenta stem cells also demonstrate characteristics of high plasticity
and low immunogenicity. "The potential application of fetal membrane-derived cells as
a therapeutic tool for disorders characterized by inflammation and fibrosis is supported
in previous studies," says Dr. Ornella Parolini, the study's lead author. "In
line with the hypothesis that cells derived from the amniotic membrane have
immunomodulatory properties and have been used as an anti-inflammatory agent, we set out
to evaluate the effects of fetal membrane-derived cell transplantation in
chemically-treated (bleomycin) mice." According to Dr. Parolini, cells delivered via
intra-peritoneal transplant, regardless of the cells being allogenic or xenogenic (host's
own cells or from another individual respectively), the procedure resulted in a
significant anti-fibrotic effect on the lab animals. A "consistent" reduction in
lung fibrosis, says Dr. Parolini, "provides convincing proof" that
placenta-derived cells do confer benefits for bleomycin-induced lung injury. While the
severity of inflammation did not show an overall reduction, there was a marked reduction
in neutrophil (white blood cell) infiltration after both xeno-and-allo-transplantation.
"It is worth noting," says Dr. Parolini," that the presence of neutrophils
is associated with poor prognosis for several lung diseases. However, the mechanism by
which placenta-derived cells might affect infiltration by neutrophils is not known."
The researchers speculated that these cells may produce soluble factors that induce
anti-inflammatory effects.
Mines could provide geothermal
energy
Mine shafts on the point of being closed down could be used to provide geothermal energy
to local towns. This is the conclusion of two engineers from the University of Oviedo,
whose research is being published this month in the journal Renewable Energy. The method
they have developed makes it possible to estimate the amount of heat that a tunnel could
potentially provide. "One way of making use of low-intensity geothermal energy is to
convert mine shafts into geothermal boilers, which could provide heating and hot water for
people living nearby", Rafael Rodríguez, from the Oviedo Higher Technical School of
Mining Engineering, tells SINC. This type of energy, which is hardly used in Spain, is
obtained from the internal heat of the Earth. The engineer and his colleague María
Belarmina Díaz have developed a "semi-empirical" method (part mathematical and
part experimental) to calculate the amount of heat that could be produced by a mine tunnel
that is due to be abandoned, based on studies carried out while it is still in use.
"When the mine is still active one can access the tunnels easily in order to gather
data about ventilation and the properties of the rocks, as well as to take samples and
design better circuits, and even programme the closure of some sections in order to use
them for geothermal energy production", says the engineer, who stresses that,
although geothermal energy can be made use of once the mine is closed, "it is no
longer possible by that stage to make any modifications, or to gather any useful data to
evaluate and improve the system".
|
|
|
|