News 20 mei 2009
Protein that suppresses androgen
receptors could improve prostate cancer diagnosis, treatment
A protein that helps regulate expression of androgen receptors could prove a new focal
point for staging and treating testosterone-fueled prostate cancer, Medical College of
Georgia researchers say. Levels of the protein, ?arrestin2, are lower in some prostate
cancer cells than in normal prostate cells while expression of testosterone-fed androgen
receptors is higher, they report in Proceedings of the National Academy of Sciences Online
Early Edition this week. "An increase in the number of androgen receptors is believed
responsible for prostate cancer progression in men with advanced disease," says the
study's corresponding author, Dr. Yehia Daaka, Distinguished Chair in Oncologic Pathology
in the MCG School of Medicine.
ISU researcher identifies genetic
pathway responsible for much of plant growth
Researchers at Iowa State University have discovered a previously unknown pathway in plant
cells that regulates plant growth. Yanhai Yin, an assistant professor in genetics,
development and cell biology, examined signaling mechanisms of a plant hormone called
brassinosteroids. The hormone controls the growth of cells. The brassinosteroids (BRs)
have a major impact on how large the plant grows, says Yin. "Previously, we knew that
steroids promote growth," said Yin. "In model plants like Arabidopsis (a
relative of mustard) and crops such as corn and rice, if you have more steroids, you have
more growth, and if you have less steroids, you have less growth and the plant is
smaller." Now Yin knows that the HERK1 (named for Hercules -- the Greek and Roman god
who possessed superhuman strength) pathway, induced by BRs, is controlling much of that
growth.
Schizophrenia does not increase
risk of violent crime
A new study from the Swedish medical university Karolinska Institutet and the University
of Oxford finds that the severe mental disorder schizophrenia only marginally increases
the risk of committing violent crime. Rather, the overrepresentation of individuals with
schizophrenia in violent crime is almost entirely attributable to concurrent substance
abuse.In the debate surrounding violent crimes referred to as "acts of madness"
or the like, it is often assumed that the violence is a direct result of the perpetrator's
mental illness. Previous research suggests that people with schizophrenia, a major
psychotic disorder, are at higher risk for violent behaviour. However, there has been some
uncertainty as to the magnitude of this risk increase and if it can really be attributed
to the violence itself or to other factors. The new study, presented in the May 20 issue
of the scientific journal JAMA, is the largest in this field to date. In it, researchers
compared the rate of violent crime in over 8,000 people diagnosed with schizophrenia
between 1973 and 2006, and a control group of 80,000 people from the general population of
Sweden. Twenty-eight per cent of those with schizophrenia and co-occurring substance abuse
were convicted of violent crime, compared to eight per cent of those with schizophrenia
and no substance abuse, and five per cent of the general population.
Old Stain in a New Combination
Methylene blue can curb the spread of malaria parasites when administered together with
new malaria medication / Heidelberg researchers publish in PLoS One. New combinations of
agents based on the oldest synthetic malaria drug, the methylene blue stain, can curb the
spread of malaria parasites and make a significant contribution to the long-term
eradication called for by the international “Roll Back Malaria Initiative.” In a
study on 160 children with malaria in Burkina Faso, specialists in tropical medicine from
the Heidelberg University Hospital have shown that in combination with newer malaria
drugs, methylene blue prevents the malaria pathogen in infected persons from being
re-ingested by mosquitoes and then transmitted to others and is thus twice as effective as
the standard therapy. The results of the study were published in May 2009 in the online
journal PLoS One. Malaria is still one of the deadliest tropical diseases. Every year, 300
million people are infected with malaria and more than one million of them die or suffer
severe brain damage. Children under five years are particularly susceptible.
Protein identified as critical to
insulating the body's wiring could also become treatment target
A new protein identified as critical to insulating the wiring that connects the brain and
body could one day be a treatment target for divergent diseases, from rare ones that lower
the pain threshold to cancer, Medical College of Georgia researchers say. They report this
week in Proceedings of the National Academy of Sciences Online Early Edition that in the
peripheral nervous system that controls arms and legs, the protein erbin regulates the
protein neuregulin 1, stabilizing and interacting with the ErbB2 receptor on Schwann cells
so they can make myelin, which insulates the wiring. Their studies in mice have shown that
when erbin is missing or mutated, the insulation is inadequate, slowing communication.
"Erbin is like a tuner to make signaling stronger or weaker," says Dr. Lin Mei,
the study's corresponding author and director of MCG's Institute of Molecular Medicine and
Genetics. Without erbin, the myelin production system falls apart. Eventually raw,
over-exposed nerves can die.
Mutant genes in high-risk childhood
leukemias identified
A research team has pinpointed a new class of gene mutations, which identify cases of
childhood acute lymphoblastic leukemia (ALL) that have a high risk of relapse and death.
The finding suggests specific drugs that could treat this high-risk leukemia subtype in
children, particularly because such drugs are already in clinical trials for similar blood
diseases in adults. While the cure rate in pediatric ALL has reached about 85 percent, the
remaining high-risk cases have proven especially intractable because they arise from
different, unidentified genetic mutations. Discovery of the mutations was led by
scientists from St. Jude Children's Research Hospital, the Children's Oncology Group
(COG), the University of New Mexico Cancer Research and Treatment Center, Albuquerque,
N.M., and the National Cancer Institute (NCI), part of the National Institutes of Health
(NIH). This research was done as part of the NCI Therapeutically Applicable Research to
Generate Effective Treatments (TARGET) initiative, which seeks to utilize the study of
genomics to identify therapeutic targets in order to develop more effective treatments for
childhood cancers. The article appears online May 18 in the early edition of the
Proceedings of the National Academy of Sciences. "We have made such great progress in
curing children with ALL that the main challenge is now the remaining high-risk
patients," said St. Jude Scientific Director, James Downing, M.D., a co-senior author
of the study. "We still do not know how to accurately identify these patients and
effectively treat them to provide the highest chance for a cure. The problem is that this
high-risk group is likely a heterogeneous mixture of biologic subtypes." The new
study builds on the researchers' previous genetic analysis of the leukemic cells from
pediatric ALL patients.
Strong immune response to new siRNA
drugs in development may cause toxic side effects
Small synthetic fragments of genetic material called small interfering RNA (siRNA) can
block production of abnormal proteins; however, these exciting new drug candidates can
also induce a strong immune response, causing toxic side effects. Understanding how siRNA
stimulates this undesirable immune activity, how to test for it, and how to design siRNA
drugs to avoid it are critical topics explored in a timely review article published online
ahead of print in Oligonucleotides, a peer-reviewed journal published by Mary Ann Liebert,
Inc. (www.liebertpub.com) The article is available free online at www.liebertpub.com/oli
siRNAs are duplex structures comprised of short oligonucleotide sequences. The discovery
that naturally occurring and synthetic siRNAs can effectively prevent expression of a
disease gene sparked intense interest in developing siRNAs as drugs. However, depending on
the structure and sequence of a siRNA and how it is delivered, it may induce a potent
innate immune response in humans, stimulating the release of inflammatory chemicals such
as cytokines and interferons. Exploring the possibility of designing synthetic siRNAs and
developing novel delivery methods that would exploit the drug-like capabilities of siRNA
while preventing toxic side effects, researchers are working to understand the mechanism
by which siRNA stimulates the immune system. In the article entitled, "siRNA and
Innate Immunity," Marjorie Robbins, Adam Judge, and Ian MacLachlan, from Tekmira
Pharmaceuticals (Burnaby, British Columbia, Canada), describe the different possible
mechanisms for siRNA-mediated immune activation in various cell types, present preferable
siRNA sequences and strategies for chemically modifying the siRNA to minimize its
immunostimulatory effects, and suggest experimental methods for studying the safety of
siRNA therapeutics.
Action of ghrelin hormone increases
appetite and favors accumulation of abdominal fat
The ghrelin hormone not only stimulates the brain giving rise to an increase in appetite,
but also favours the accumulation of lipids in visceral fatty tissue, located in the
abdominal zone and considered to be the most harmful. This is the conclusion of research
undertaken at Metabolic Research Laboratory of the University Hospital of Navarra,
published recently in the International Journal of Obesity. Ghrelin is a hormone produced
in the stomach and the function of which is to tell the brain that the body has to be fed.
Thus, the level of this secretion increases before eating and decreases after. It is known
to be important in the development of obesity, given that, on stimulating the appetite, it
favours an increase in body weight, explained Ms Amaia Rodríguez Murueta-Goyena, doctor
in biology and main researcher of the study. However, researchers at the University
Hospital of Navarra have discovered that, besides stimulating the hypothalamus to generate
appetite, ghrelin also acts on the tabula rasa cortex. They observed how this hormone
favoured the accumulation of lipids in visceral fatty tissue. In concrete, it causes the
over-expression of the fatty genes that take part in the retention of lipids, explained Ms
Rodríguez. It is precisely this accumulated fat in the region of the abdomen that is
deemed to be most harmful, as it is accompanied by comorbilities, visceral obesity being
related to higher blood pressure or type 2 diabetes. Moreover, being located in the
abdominal zone and in direct contact with the liver, this type of fatty tissue favours the
formation of liver fat and increases the risk of developing resistance to insulin.
Normally, on being associated with hypertension, high levels of triglycerides, resistance
to insulin and hypercholesterolemia, visceral fat favours the metabolic syndrome, the
researcher pointed out. Ghrelin can show itself in acylated or deacylated form, the
difference being in the octanoic acid present in the composition of the former, according
to Ms Rodriguez. Previously it was thought that only the acylated form was active in the
process of weight increase, but many studies point to both hormones being biologically
functional.
New strategies for cell therapy to
regenerate damaged heart
Research undertaken at the Center for Applied Medical Research (CIMA) and the University
Hospital of Navarra has shown that, in animal models, stem cells derived from bone marrow
and adipose tissue enhance heart function after a cardiac attack. In concrete, bone marrow
cells act on the damaged tissue, while fatty cells have the ability to transform
themselves into both blood vessels and cardiac cells. The results obtained with rats are
maintained over a long time period, explained biochemist Mr Manuel Mazo, principal
researcher. When a person suffers a heart attack, the artery feeding the heart is
obstructed The affected tissue dies and the scar tissue left des not contract. It is a
serious problem as cardiac muscle does not regenerate, with grave consequences for the
functional capacity of the heart, a situation which can trigger heart failure, explained
the scientist.
Geothermal energy - Instant Steam
gets into hot water
Geothermal energy -- thermal energy stored in the Earth’s crust – currently
supplies less than 1% of the world's energy. But with the advent of new technologies, such
as engineered geothermal systems (EGS) -- which can extract enough heat from lower grade
geothermal resources to generate electricity – geothermal energy could potentially be
used to produce enough electricity to meet a large portion of the world's energy demands.
A memorandum of understanding (MOU) signed between Oxford Catalysts and Potter Drilling to
explore the application of Oxford Catalysts' Instant Steam technology to Potter Drilling's
hydrothermal spallation drilling technology could bring the dream of widespread geothermal
electricity generation much closer. Geothermal wells can be slow and expensive to drill
using conventional rotary drilling methods. This is because the wells are often sunk deep
into hard crystalline rocks which are difficult and slow to penetrate and which quickly
wear down the drill bits. The slow penetration rates combined with the need for frequent
trips out of the hole to change bits adds greatly to the cost of the wells. Potter
Drilling's spallation technology overcomes these problems by using superheated fluid to
drill through the rocks, rather than relying on the abrasive cutting power of a rotating
drill bit. Under the terms of the MOU the two companies will be carrying out trials to
explore the application of Oxford Catalysts' Instant Steam technology to generate the
necessary heat for use in Potter Drilling's spallation drilling tool. In these tests the
Instant Steam catalyst will be contained in the drill head, which is attached to a
flexible coiled pipe that can be pulled out of the well quickly when required.
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