Anaesthetics & Alzheimer’s
Researchers at the
University of Pennsylvania’s
School of Medicine have
discovered that common
inhaled anaesthetics increase
the number of amyloid
plaques in the brains of
animals, which might accelerate
the onset of neurodegenerative
diseases like
Alzheimer’s.
Roderic
Eckenhoff, MD, Vice Chair
of Research in the
University of Pennsylvania’s
Department of Anesthesia
and Critical Care, and his
co-authors, report their
findings in the 7 March
online edition of
Neurobiology of Aging.
Every year over 100
million people undergo
surgery worldwide, most
under general anaesthesia
with an inhaled drug. These
drugs clearly affect cognitive
ability at least in the short
term, but the growing
concern is that inhaled
anaesthetics may affect a
person well beyond the perioperative
period, even
permanently.
Several factors
appear to play a role in this
subtle loss of cognitive
ability, most notably age.
A specific effect of these
drugs on dementias like
Alzheimer’s disease, though
suspected for many years,
has only been recently
supported by data.
The genomes of the largest
collection of families with
multiple cases of autism
ever assembled have been
scanned in a new study. The
results provide new insights
into the genetic basis of
autism, according to a report published online in
Nature Genetics.
Autism spectrum disorders
(ASD) influence social
interaction and communication
and affect 6 out of
every 1,000 children.
The
Autism Genome Project
Consortium – comprising 50 centres in North America
and Europe – collected DNA
samples from nearly 1,500
families, each of which has
more than two members
with ASD.
The team carried out a
two-fold analysis.
First they
assessed the frequency of
alterations in copy number
of different segments of the
genome, finding an unexpectedly
high percentage of
the families – 7 to 12%,
depending on how the
analysis was done – in
which all affected individuals
share possibly detrimental
chromosomal
abnormalities.
Two female
siblings had deletions of the
gene encoding the protein neurexin 1, which interacts
with neuroligins — a family
of proteins that have been
implicated in some cases of
autism. Finally, the authors
carried out a ‘linkage’
analysis of these families,
searching for regions of the
genome that might be
shared by the individuals
with ASD.
One particular
region on chromosome 11
was identified, which has
not previously been reported
to harbour genes that affect
risk of developing autism.
A paradigm shift in medical
education is needed, one
with more emphasis on
training future physicians to enhance their empathy
skills and to learn to view
patients as persons, not just
cases, a medical education
specialist at Jefferson
Medical College, Philadelphia,
Pennsylvania, says.
“If we want to train physicians
with more empathy,
then education must shift
from emphasising only the
biomedical to also providing
a biopsychosocial framework,
as well and a more
complete picture of patients
as persons,” says
Mohammadreza Hojat,
PhD, research professor of
psychiatry and human
behaviour at Jefferson
Medical College.
According to Dr Hojat,
who has written a book,
Empathy in Patient Care:
Antecedents, Development,
Measurement, and Outcomes,
(Springer-Verlag 2007), much
emphasis is placed on the
biomedical paradigm of
health and illness, which is
akin to treating the organ
affected by disease rather
than curing the patient’s
illness.
“The thinking is,
once you treat the organ,
the patient is fine,” he says.
“This is a unidimensional
approach to patient care.
Health is not simply defined
as absence of disease – it
encompasses the physical,
mental and social well being
of a person.”
The book is aimed at
physicians, medical students,
residents, psychologists,
clinical social workers and
any other health professionals
involved in patient
care. It serves as a platform,
he says, to discuss factors
that contribute to empathy
development, such as genetic, social and educational
factors, and
approaches to enhance
empathy. Dr Hojat is
convinced that a caregiver’s
empathic abilities can influence
how a patient fares.
“It’s important to consider
the potential role of
empathic ability in clinical
outcome,” he says. “When
the patient feels the physician
can understand him or
her, that in itself seems to
have a therapeutic effect.”
In 2001, Dr Hojat and his
colleagues developed the
Jefferson Scale of Physician
Empathy. The scale, which
has already been translated
into 15 languages and is
used by researchers worldwide,
is the only psychometrically
sound instrument
available for specifically
measuring empathy among
physicians and medical
students.
A new digital ophthalmoscope,
devised by a research
team led by the University
of Warwick in the UK, can
provide both doctors and
optometrists with a handheld
eye disease diagnosis
device equal to the power of
bulky hospital-based eye
diagnosis cameras. It will
also give optometrists the
ability to email detailed eye
maps of patients to
specialist eye doctors.
Ophthalmoscopes, which
act as an illuminated microscope
for the eye, have
changed little in design in
the last century. As a result
the effective operation of
the device is constrained by
the skill, expertise and
eyesight of the eye specialist.
The new digital ophthalmoscope
uses a combination
of specialist lens digital
imaging and lighting technology
which for the first
time allows a high quality
digital image to be captured
and recorded by an ophthalmoscope.
The most important genes
associated with a risk of
developing type-2 diabetes
have been identified, scientists
report in a new study.
The research, published
online in Nature in February,
is the first time the genetic
makeup of any disease has
been mapped in such detail.
It should enable scientists to
develop a genetic test to
show an individual their
likelihood of developing
diabetes mellitus type 2.
The scientists believe their
findings explain up to 70%
of the genetic background
of type-2 diabetes.
In addition, one of the
genetic mutations which
they detected might further
explain the causes behind
type-2 diabetes, potentially
leading to new treatments.
The research revealed that
people with type-2 diabetes
have a mutation in a particular
zinc transporter known
as SLC30A8, which is
involved in regulating
insulin secretion.
Type-2
diabetes is associated with a
deficiency in insulin and
the researchers believe it
may be possible to treat it by
fixing this transporter.
Professor Philippe Froguel,
one of the authors of the
study from the Division of
Medicine at Imperial
College London, said:
“The two major reasons why
people develop type-2
diabetes are obesity and a
family link. Our new findings
mean that we can
create a good genetic test to
predict people’s risk of
developing this type of
diabetes.
“If we can tell someone
that their genetics mean
they are pre-disposed towards
type-2 diabetes, they will be
much more motivated to
change things such as their
diet to reduce their chances
of developing the disorder.
We can also use what we
know about the specific
genetic mutations associated
with type-2 diabetes to
develop better treatments.”
An important step in the
effort to compile a complete
catalogue of functional
elements in the human
genome was published in
the March issue of Nature
Genetics.
A specific chemical
signature of DNA sequences
that promote the expression
of nearby genes has been
identified, and researchers
should now be able to more
accurately predict the location
and function of these
sequences.
Analysis of the complete
sequence of the human
genome has identified
approximately 25,000 genes,
but genes comprise only a
small fraction of the
genome. At least some of
the remainder of the genome
consists of sequences called
promoters and enhancers
that determine when,
where, and to what extent
each of these genes will be
expressed.
While promoters are typically found immediately
adjacent to genes,
enhancers can be located
much further away, making
it difficult to identify them.
Bing Ren and colleagues
examined 1% of the human
genome and catalogued a
number of different chemical
modifications that are
made to histones, which
are proteins that bind to
and package DNA, and are
known to be involved in
gene regulation.
They found
that the histones bound to
known promoters are
marked by chemical modifications
that are distinct
from those found on
histones bound to
enhancers. This information
enabled the authors to
accurately predict the location
and function of
promoters and enhancers
that were independently
identified, as well as identify
a previously undiscovered
enhancer.
Women who have been
diagnosed with breast
cancer in one breast have a
higher risk of contracting
the disease in their opposite
breast as well.
A thorough
examination of the opposite
breast using mammography
and ultrasound is therefore
common practice. However,
many tumours still remain
undetected when using
mammography. Magnetic
resonance imaging (MRI)
promises better results, as is
shown in an international
study involving the
University of Bonn.
In
almost 1,000 women with a
recent diagnosis of breast
cancer in one breast, MRI
helped identify 30 cancers
in the seemingly normal opposite breast. In women
with a normal (negative)
MRI of the opposite breast,
there was a 99.6% confidence
that in fact no breast
cancer was present - which
means that if the MRI study
is normal, preventive
mastectomy of the opposite
breast, which some women
want, is definitely unnecessary.
These findings have
been published in the 29
March issue of the New
England Journal of Medicine.
Seoul, Korea-based Medison,
a manufacturer of diagnostic
ultrasound systems,
has been awarded the prestigious
Frost & Sullivan
Competitive Strategy Leadership
Award for 2007 for its
strategic initiatives to establish
itself as a leading enterprise
in the European ultrasound
market.
“Medison has accomplished
high growth in the
world’s biggest and most
advanced market, Europe,
by aggressive strategies and
customer-oriented management,”
said Karthik Arun,
head analyst, Frost & Sullivan.
The company implemented
an aggressive
strategy to achieve a significant
market share, particularly
in the high-end 3D
ultrasound segment across
Europe. Medison commanded
a market share of nearly
40% in the high-end 3D and
4D ultrasound segment in
Europe last year.
Fraunhofer researchers have
developed a smart sensor
network for monitoring
cardiovascular patients. The
researchers presented the
‘mobile health assistant’ at the CeBIT fair in Hanover,
Germany in March.
Six Fraunhofer Institutes
have spent two years
working on a system that
can record the main cardiovascular
functions 24 hours
a day over a long period of
time and enables communication
with qualified
medical staff.
The key components of
the mobile health assistant
were developed in a joint
Fraunhofer project entitled
senSAVE (Sensor Assistance
for Vital Events).
Along with
comfortable, easy-to-wear
sensors that constantly
measure all the necessary
data and transmit them by
radio to a PDA, the assistant
has the necessary software
to collect and analyse the
flood of information and
send it via Internet or
mobile network to a
telemedical support centre,
where trained staff can
assess how critical the situation
is, advise patients over
the phone, and call a doctor
if necessary.
It was a challenging task
to find suitable electrodes
for channelling the ECG
readings, as they would
need to be in permanent
contact with the patient’s
skin for days at a time say
the researchers. They developed
a highly flexible dry
electrode that can be woven
into the elastic fibres of a
sensor shirt. Potential
wearers are fitted with their
own tailor-made sensor
shirt. The sheer pressure of
the garment is sufficient to
establish contact between
the skin and the adhesive
electrodes. A second layer of
fabric covers the sensor
wiring and the electronic
circuit board.
The oxygen saturation of
the blood and the pulse
wave curve are determined
by a pulse oximeter. Until
now the pulse oximeter has
been pushed over the index
or middle finger with a
commercially available
finger clip. In future it will
be integrated in a strap to be
worn on the person’s wrist.
From there, the readings
will be radioed to a miniature
computer, such as a
smart phone or a PDA, which
at the same time receives the
ECG readings.
The time
difference between these two
sets of readings yields the
pulse wave transit time, from
which it is possible in turn to
deduce the blood pressure
transit time – non-stop, 24
hours a day.
Scientists at St George’s,
University of London, are
working on a blood test that
uses DNA markers to identify
prostate cancer cells that
are shed into the bloodstream.
The researchers have
demonstrated that by measuring
the levels of these
markers, not only can an
accurate diagnosis of cancer
be made, but the stage the
cancer has reached –
whether it is still localised or
already has spread and
become metastatic – can be
identified.
In addition, certain
markers, if switched on, will
hopefully give information
on how quickly the cancer
will develop, and, therefore,
when treatment must be
introduced.
The current, most widely
used method of detecting
prostate cancer is the serum
Prostate Specific Antigen (PSA) test, which is only
50% accurate.
Increased
levels of PSA are elevated in
non-malignant conditions,
such as benign prostatic
hyperplasia, prostatitis and
even urinary tract infections.
This new test, which
is able to detect one prostate
cancer cell among a sample
of 100 million blood cells, is
95% accurate.
The test is currently at the
stage of validation, with
further development regarding
standardisation and formatting,
and could be introduced
on to the market next year.
Increasing rates of childhood
obesity and overweight
in the United States
may be contributing to an
earlier onset of puberty in
girls, say researchers at the
University of Michigan CS
Mott Children’s Hospital, in
the US.
In a new study published
in the March issue of the
journal Pediatrics, the
researchers reveal that a
higher body mass index
(BMI) score in girls as young
as age 3, and large increases
in BMI between 3 years of
age and first grade are associated
with earlier puberty,
defined as the presence of
breast development by age
9.
This longitudinal study is
unique in that it included
girls younger than age 5 to
examine the association
between weight status and
timing of puberty.
“Our finding that
increased body fatness is
associated with the earlier
onset of puberty provides
additional evidence that
growing rates of obesity
among children in this
country may be contributing to the trend of
early maturation in girls,”
says lead author and U-M paediatric endocrinologist
Joyce Lee, MD, MPH.
Studies have suggested
that girls in the United
States are entering puberty
at younger ages today than
they were 30 years ago, says
Lee. Since rates of childhood
obesity also have significantly
increased during the
same time period,
researchers have speculated
that childhood obesity may
be contributing to a trend of
earlier puberty in girls.
Studies have shown that
earlier onset of puberty can
lead to higher rates of behavioural problems and
psychosocial stress.
A team of Danish scientists
has shown that nerve
impulses transmit by sound
and that the common view
that nerves transmit
impulses through electricity
is wrong.
A new international Task
Force under the auspices of
the Global Health
Workforce Alliance was
launched and met for the
first time in Geneva in
March to tackle the global
shortage of health workers.
With a shortfall of 4.3
million health workers
worldwide, including more
than 1 million in Africa
alone, there is an urgent
need to increase the number
of doctors, nurses, health
managers and other healthcare
workers needed to face
immediate health crises.
Dr Margaret Chan,
director-general of the
World Health Organisation, welcomed the new Task
Force saying: “The simple
fact is that the world needs
many more health workers.
The world faces global as
well as local threats to
health. Infectious diseases
have staged a dramatic
comeback, and chronic
diseases are on the rise. We
cannot improve people’s
health without staff to
deliver health care.
The task force will champion
the need for significantly
increased investment
in the education and
training of health workers in
developing countries, and
will build international
commitment to practical
action. It will focus on practical
solutions and consider
the need and scope for
financial and technical
support internationally.
The Times of London reports
that doctors in England
have invented a novel artificial
vein that could offer
hope to people with clogged
arteries.
The plastic artificial vein
is “rifled” inside which
encourages the blood to
spiral when it flows through
it, mimicking the normal
corkscrew motion of blood
through the body’s veins
and arteries.
Results from human trials
of the new plastic vein –
which is being developed
for use in bypass operations
– have shown a 100%
success rate in the first six
months.
According to researchers
involved with the development
– the simple adjustment
from a smooth to a
rifled vein has produced
remarkable results in human trials.
Professor Peter Stonebridge,
who set up Tayside Flow
Technologies with John
Dick and Graeme Houston,
from Ninewells Hospital in
Dundee, UK, to develop the
product, was quoted in the
report as saying: “One
would have expected some
of the bypass grafts [artificial
veins] in the trials to
have failed, but none have.
They are all still going
which is remarkable.”
According to the report,
seven out of ten “smooth”
artificial arteries used in
below-the-knee bypass operations
fail in less than two
years and about 40% of
patients need a limb amputated.
On that basis, approximately
20% of the new
“spiral” veins implanted
into the legs of 22 trial
patients should have stopped
working after six months.
But so far all the grafts have
stayed open and bloodflow
speed has remained constant.
Scientists have discovered a
new source of stems cells
and have used them to
create muscle, bone, fat,
blood vessel, nerve and liver
cells in the laboratory.
The
first report showing the
isolation of broad potential
stem cells from the amniotic
fluid that surrounds developing
embryos was
published recently in Nature
Biotechnology.
“Our hope is that these
cells will provide a valuable
resource for tissue repair
and for engineered organs
as well,” said Anthony Atala, MD, senior researcher
and director of the
Institute for Regenerative
Medicine at Wake Forest University School of
Medicine, in the United
States.
The scientists believe the
newly discovered stem cells,
which they have named
amniotic fluid-derived stem
(AFS) cells, may represent an
intermediate stage between
embryonic stem cells and
adult stem cells.
They have
markers consistent with
both cell types.
An advantage of the AFS
cells for potential medical
applications is their ready
availability. The report
describes how the cells were
harvested from backup
amniotic fluid specimens
obtained for amniocentesis,
a procedure that examines
cells in this fluid for
prenatal diagnosis of certain
genetic disorders. Similar
stem cells were isolated from
“afterbirth,” the placenta and
other membranes that are
expelled after delivery.
In addition to being easily
obtainable, the AFS cells can
be grown in large quantities
because they typically
double every 36 hours.
They also do not require
guidance from other cells
(termed “feeders”) and
they do not produce
tumours, which can occur
with certain other types of
stem cells.
The scientists
noted that specialised cells
generated from the AFS cells
included all three classes of
cells found in the developing
embryo – termed
ectoderm, mesoderm, and
endoderm. In their high
degree of flexibility and
growth potential, the AFS
cells resemble human
embryonic stem cells, which
are believed capable of
generating every type of
adult cell.
