News 19 march 2009
Scientists closer to understanding
how to control high blood sugar
Scientists are closer to understanding
which proteins help control blood sugar, or glucose, during and after exercise. This
understanding could lead to new drug therapies or more effective exercise to prevent Type
2 diabetes and other health problems associated with having high blood sugar. Insulin
resistance happens when insulin produced by the body doesn't properly stimulate the
transport of glucose into the cells for energy. Too much glucose in the bloodstream can
cause a host of medical problems, including Type 2 diabetes, said Gregory Cartee,
professor at the University of Michigan School of Kinesiology. Insulin and muscle
contractions are the two most important stimuli to increase glucose transport into muscle
cells. Cells then use the glucose for energy. However, scientists aren't entirely sure how
this works. Cartee and colleague Katsuhiko Funai, a graduate student researcher in
kinesiology, looked at how two different proteins believed to be important in stimulating
glucose transport react to two different enzymes also related to glucose transport. The
goal of the study was to understand the contribution of the two proteins, AS160 and
TBC1D1, in skeletal muscle stimulated by insulin. "We're trying to rule out or rule
in which proteins are important with exercise," Cartee said.
U.S. trial shows no early mortality
benefit from annual prostate cancer screening
The prostate cancer screening tests that
have become an annual ritual for many men don't appear to reduce deaths from the disease
among those with a limited life-expectancy, according to early results of a major U.S.
study involving 75,000 men. Results released today from the Prostate, Lung, Colorectal and
Ovarian (PLCO) Cancer Screening Trial show that six years of aggressive, annual screening
for prostate cancer led to more diagnoses of prostate tumors but not to fewer deaths from
the disease. The study, led by researchers at Washington University School of Medicine in
St. Louis and conducted at 10 sites, will appear online March 18 in the New England
Journal of Medicine (and in the journal's print edition on March 26). "The important
message is that for men with a life expectancy of seven to 10 years or less, it is
probably not necessary to be screened for prostate cancer," says the study's lead
author and principal investigator Gerald Andriole, M.D., chief urologic surgeon at the
Siteman Cancer Center at Washington University School of Medicine and Barnes-Jewish
Hospital.
Scientists trial device to treat
chemotherapy-related nausea
Trials to test acupressure wrist bands as a
drug-free alternative for chemotherapy-related nausea are to take place at the University
of Liverpool. More than 75% of patients undergoing chemotherapy experience nausea, which
can impact negatively on their quality of life. Acupressure wrist bands can reduce the
symptoms of travel sickness by applying force to the Nei Kuan pressure point on each
wrist. The national study of more than 700 patients, at nine NHS cancer centres, will now
measure the cost and clinical effectiveness of acupressure wrist bands in reducing and
controlling chemotherapy-related nausea. Led by Professor Mari Lloyd-Williams, from the
University’s Academic Palliative and Supportive Care Studies Group, the team will
analyse a wide range of patients, diagnosed with different types of cancer and undergoing
chemotherapy, in order to discover which patient groups would most benefit from the
intervention. Professor Lloyd-Williams said: “Developments in anti-emetic drugs
– used to combat nausea and vomiting – have decreased the symptoms suffered by
chemotherapy patients but nausea remains a debilitating and poorly controlled symptom.
“Patients rank nausea and vomiting amongst the most distressing side effects of
chemotherapy. In some cases, poorly controlled symptoms can lead to patients choosing to
stop potentially curative treatment. These symptoms can contribute towards a loss of
social life, prevent people from working, and lead to anxiety and depression.
Report warns of jury service
'trauma'
A new report by psychologists at the
University of Leicester warns of the dangers of jurors facing trauma because of their
exposure to harrowing and gruesome evidence. In the first study of its kind, the research
highlights how women jurors are more vulnerable, particularly if the trial covers material
that resonates with their personal histories. The research confirms that jury service,
particularly for crimes against people, can cause significant anxiety, and for a
vulnerable minority it can lead to severe clinical levels of stress or the symptoms of
post traumatic stress disorder. The study led by clinical psychologist Dr Noelle Robertson
has been published in The Howard Journal. It warns of the perils of undergoing jury
service- and the fact that people cannot talk about their experiences for fear of being
held in contempt of court. Dr Robertson, with University of Leicester colleagues Professor
Emeritus Graham Davies and graduate student Alice Nettleingham, is the first UK
exploratory study to look at the possible traumatisation of jurors.
When intestinal bacteria go surfing
The EHECs adhere to the surface of the
mucosal cells and alter them internally: a part of the cellular supportive skeleton - the
actin skeleton - is rearranged in such a manner that the cell surface beneath the bacteria
forms plinth-like growths, so-called pedestals. The bacteria are securely anchored to this
pedestal; the pedestals, in contrast, are mobile. This enables the bacteria, seated upon
them, to surf over the cell surface and reproduce upon it, without being flushed from the
intestine. But how do the bacteria bring the host cells to convert the actin skeleton?
Researchers at the Helmholtz Centre for Infection Research (HZI) have now identified the
signal pathway that leads to the formation of this pedestal. "Prerequisite for this
signal pathway is a special secretion system - a sort of molecular syringe, through which
the bacteria insert entire proteins in the host cell," explains Theresia Stradal,
head of the Signal Transduction and Motility research group at HZI. Two factors, Tir and
EspFU, are brought into the host cell from the bacterium for pedestal formation. Following
this, the host cell presents Tir on its surface; the bacterium recognises "its"
molecule Tir and adheres to the host cell. EspFU then triggers the signal for local actin
conversion. "It has been unclear thus far how the two bacterial effectors Tir and
EspFU enter into contact with one another in the host cell," says Theresia Stradal.
Her research group has now found the missing link: "The molecule comes from the host
cell, is called IRSp53 and gathers on the cell surface, directly beneath the bacteria
sitting on it," explains cell biologist Markus Ladwein, who is also involved in the
project. IRSp53, then, establishes the connection between Tir and EspFU. It ensures that
actin conversion is concentrated locally. Together with the biochemist Dr. Stefanie Weiß,
a former post-graduate student with the research group, Markus Ladwein also provided the
counter evidence: "Cells in which IRSp53 is lacking are no longer able to form
pedestals for the bacteria."
Study finds biological clue in
brain tumour development
Scientists at The University of Nottingham
have uncovered a vital new biological clue that could lead to more effective treatments
for a children’s brain tumour that currently kills more than 60 per cent of young
sufferers. Clinician –scientists at the University’s Children’s Brain
Tumour Research Centre, working on behalf of the Children’s Cancer and Leukaemia
Group (CCLG), have studied the role of the WNT biological pathway in central nervous
system primitive neuroectodermal tumours (CNS PNET), a type of brain tumour that
predominantly occurs in children and presently has a very poor prognosis. In a paper
published in the British Journal of Cancer, they have shown that in over one-third of
cases, the pathway is ‘activated’, suggesting that it plays a role in tumour
development. The research also highlighted a link between WNT pathway activation and
patient survival — patients who had a CNS PNET tumour that was activated survived for
longer than those without pathway activation. The reason for the link between WNT pathway
activation and better patient prognosis is as yet unclear. It could be that these tumours
represent a less aggressive subset or that pathway activation itself actually harms the
tumour. However, the pathway could represent an important new target for the treatment of
more effective drugs, with fewer side effects.
Study finds extensive patient
sharing among hospitals; could impact spread of infectious diseases
Findings from the first in-depth study of
patient sharing show that hospitals share large numbers of patients with other acute care
facilities without knowing it. In the new study released today at the annual meeting of
the Society for Healthcare Epidemiology of America (SHEA), researchers found that only one
in nine shared patients is directly transferred from one hospital to another, whereas most
patients were discharged before being readmitted to another hospital. This high
underestimation of patient sharing has important implications for handling the potential
spread of infectious disease among acute care facilities, since patient sharing could be
an avenue of transmission if a major disease outbreak were to occur. "We were
surprised to find extensive interlinking of all the hospitals included in the study,"
said Susan S. Huang, MD, MPH, assistant professor and hospital epidemiologist, University
of California Irvine School of Medicine and SHEA member. "The level of patient
sharing among hospitals is grossly underestimated because patients often don't transfer
directly between hospitals." The study included nearly 240,000 patient admissions.
Researchers assessed direct and indirect transfers among all 31 acute care hospitals in
Orange County, CA, a large metropolitan county of three million people, using a
retrospective evaluation of 2005 California Hospital Discharge Data. Huang and colleagues
examined the likelihood that adult patients admitted to each hospital in 2005 would
subsequently be transferred or admitted to another hospital in the county in the 365 days
following their discharge. This research did not include skilled nursing homes,
psychiatric hospitals or rehabilitation facilities, which according to Huang could mean
that the amount of patient sharing among all healthcare facilities is even higher than
their study found. A large number of people (22 percent) who are discharged from acute
care facilities are readmitted elsewhere within one year. Huang attributed the intricate
and broad connections among hospitals to three primary factors: patient choice, insurer
agreements among hospitals and immediacy of needing care.
Why we have difficulty recognizing
faces in photo negatives
Humans excel at recognizing faces, but how
we do this has been an abiding mystery in neuroscience and psychology. In an effort to
explain our success in this area, researchers are taking a closer look at how and why we
fail. A new study from MIT looks at a particularly striking instance of failure: our
impaired ability to recognize faces in photographic negatives. The study, which appears in
the Proceedings of the National Academy of Sciences this week, suggests that a large part
of the answer might lie in the brain's reliance on a certain kind of image feature. The
work could potentially lead to computer vision systems, for settings as diverse as
industrial quality control or object and face detection. On a different front, the results
and methodologies could help researchers probe face-perception skills in children with
autism, who are often reported to experience difficulties analyzing facial information.
Anyone who remembers the days before digital photography has probably noticed that it's
much harder to identify people in photographic negatives than in normal photographs.
"You have not taken away any information, but somehow these faces are much harder to
recognize," says Pawan Sinha, an associate professor of brain and cognitive sciences
and senior author of the PNAS study. Sinha has previously studied light and dark
relationships between different parts of the face, and found that in nearly every normal
lighting condition, a person's eyes appear darker than the forehead and cheeks. He
theorized that photo negatives are hard to recognize because they disrupt these very
strong regularities around the eyes. To test this idea, Sinha and his colleagues asked
subjects to identify photographs of famous people in not only positive and negative
images, but also in a third type of image in which the celebrities' eyes were restored to
their original levels of luminance, while the rest of the photo remained in negative.
Research yields potential target
for cancer, wound healing and fibrosis
Research conducted by Allison Berrier, PhD,
Assistant Professor of Oral and Craniofacial Biology at the LSU Health Sciences Center New
Orleans School of Dentistry, and colleagues, provides insights that may help scientists
design novel approaches to control wound healing and fight diseases such as cancer and
fibrosis. The paper, ?1 Integrin Cytoplasmic Domain Residues Selectively Modulate
Fibronectin Matrix Assembly and Cell Spreading through Talin and Akt-1, will be published
in the March 20, 2009 issue of the Journal of Biological Chemistry. The research team also
included Drs. J. Angelo Green and Kenneth Yamada at the National Institute of Dental and
Craniofacial Research, as well as Dr. Roumen Pankov at Sofia University in Sofia,
Bulgaria. The research concerns the regulation of integrins – proteins on the surface
of cells that serve dual roles of anchoring cells within tissues and controlling cell
behavior. Integrins anchor to extracellular proteins found outside the cell and this
contact regulates important cellular activities that are critical for survival,
proliferation and differentiation in both healthy tissues and tumors. Integrins are
involved in the cellular response to injury and infection and are needed to repair damaged
tissue. Of the many integrins that exist, the beta-1 integrin is of great interest because
it is involved in nearly every cell in the body. Its importance is demonstrated by the
fact that mice, which are typically used as models for disease, cannot survive without the
beta-1 integrin gene. Beta-1 integrin is a cell surface protein that spans the membrane
and has a portion of the protein outside the cell and a portion of the protein inside the
cell. The beta-1 integrin tail is the portion found inside the cell. The beta-1 integrin
tail has two functions -- it connects integrins to the cellular infrastructure and to
signaling pathways. This study advances earlier research on the beta-1 integrin tail, that
revealed the ability of this integrin tail to provide a scaffold for signaling proteins
that control cell survival. The extracellular matrix is a complex mixture containing
proteins such as fibronectin and collagen that provide structural support to cells and
traction for cell movement. If cells are placed on top of extracellular matrix proteins
the cells become activated by their integrins and trigger signaling for the cell to expand
or spread over the matrix. Cell spreading is an intermediate step during cell migration on
matrix proteins. Prior to the current study it was not clear whether the beta-1 integrin
tail recruits the same or different proteins inside the cell to control two different
integrin receptor functions outside the cell, namely, formation of fibronectin fibrils and
cell spreading.
Conflicts of interest in clinical
research
Although paying finder's fees to
researchers and clinicians to identify study participants could compromise the recruitment
process and harm human lives, many medical schools fail to address this conflict of
interest in their Institutional Review Board (IRB) policies. Leslie Wolf, an associate
professor of law at Georgia State University, studied the IRB policies posted on the Web
sites of 117 medical schools that received National Institutes of Health funding. Among
the study's findings, Wolf revealed that less than half of the IRB policies discuss
finder's fees or bonus payments as conflicts of interest, where research sponsors pay
members of the research team or clinicians to identify potential participants or for
meeting predetermined enrollment targets. "Since IRBs must review research protocols,
and also are in a position to educate investigators about these issues, I thought their
policies were an important place to look," Wolf said. "I thought they would have
tried to address it more frequently than they did. That's a gap in IRB guidance."
Finder's fees raise concern because researchers and their colleagues may be tempted to
enroll individuals in studies for which they are ineligible, Wolf said. Wolf is also
concerned that only 26 of the IRBs in the study mentioned potential conflicts when
physicians recruit their own patients and that only four percent ask doctors to tell their
patients that they are not obligated to participate. "It was talked about much less
frequently than either the employer/employee or the teacher/student role conflict. It's
been in the literature and patients may be particularly vulnerable," Wolf said.
Concerns about conflicts of interest are only continuing to grow as more stories appear in
the news, Wolf said. For instance, Ellen Roche, a healthy 24-year-old who died from lung
failure in 2002, while in a study sponsored by her employer, the Johns Hopkins Asthma and
Allergy Center. Roche became ill after she inhaled an experimental compound as part of a
study to understand the cause of asthma. An external committee that reviewed the
circumstances of the death expressed concerns that there were "subtle coercive
pressures" on employees to enroll in the Center's studies. Employees who participated
in the study not only received compensation for participation, but were given time off
from the workday to undergo study procedures. "There have been situations that people
have talked about in the media that undermine our confidence in research and could prevent
important research from going forward," Wolf said. "We need to have a
trustworthy research enterprise so that we can get good research that hopefully improves
the lives of the rest of us."
Preterm Birth Rate Drops
The nation’s preterm birth rate
declined slightly in 2007 – a finding that the March of Dimes hopes will prove to be
the start of a new trend in improved maternal and infant health. The preterm birth rate
declined for babies born at 34-36 weeks gestation (late preterm) and among babies born to
African American and white women. “We’re encouraged by this drop in the preterm
birth rate, and hope that the emphasis we’ve put on the problem of late preterm birth
is beginning to make a difference,” said Jennifer L. Howse, Ph.D., president of the
March of Dimes. “Through our Prematurity Campaign, we can build on this success and
begin to give more babies a healthy start in life.” The rate of preterm births (less
than 37 weeks gestation) dropped to 12.7 percent from 12.8 percent in 2006, a small but
statistically significant decrease, according to preliminary birth data for 2007 released
by the National Center for Health Statistics.
Barriers to diabetes care include
restaurants and high-risk lifestyles, says international review
Eating out, lack of social support and
high-risk lifestyles are just some of the barriers that stop patients with type 2 diabetes
from controlling their condition, according to a research review that covered 8,900
patients and 4,550 healthcare providers from 28 countries. The study, published in the
March issue of the Journal of Nursing and Healthcare of Chronic Illness, shows that
psychosocial, socioeconomic, physical, environmental and cultural factors can provide
major barriers to effective care. Researchers from Hong Kong and Northern Ireland (UK)
studied research carried out between 1986 and 2007 to try and identify how treatment
regimes could be improved. Their findings have enabled them to come up with a three-point
plan for nurses involved in diabetes care. “Diabetes is a chronic condition and
patients need to modify their lifestyle on a long-term basis to cope with it” says
Sandra Pun from the School of Nursing at The Hong Kong Polytechnic University.
