Tripura Times, Agartala, Wednesday, July 02, 2014
6
HEALTH & MEDICINE
Liver preservation extended Scientists show bacteria can evolve
for transplantation: Study biological timer to survive antibiotics
Researchers have developed a new supercooling
technique to increase the amount of time human organs
could remain viable outside the body. This study was
conducted in rats, and if it succeeds in humans, it would
enable
a
world-wide
allocation of donor organs,
saving more lives.
The research is supported by
National
Institute
of
Biomedical Imaging and
Bioengineering (NIBIB) and
the National Institute of
Diabetes and Digestive and
Kidney Disease (NIDDK),
both parts of the National
Institutes of Health.
The first human whole organ
transplant 60 years ago — a
living kidney transplant —
changed the landscape of the medical world. Since then,
transplants of skin, kidneys, hearts, lungs, corneas, and
livers have become commonplace but due to a shortage
of donor organs, more than 120,000 patients are still on
waitlists for organ transplantation in the United States
alone. Current technology can preserve livers outside the
body for a maximum of 24 hours using a combination of
cold temperatures and a chemical solution developed by
scientists at the University of Wisconsin-Madison in 1983.
The solution helps keep the liver tissue from dying while
in transit to the recipient site. This has helped increase
the number of successful liver transplants — but extending
even further the time a liver can survive outside the body
would provide many benefits.
It would allow for more time to prepare the patient and
ease logistics at the donor hospital site, reduce the
urgency of rushing the organ
to its destination, and expand
the donation area to allow for
transcontinental
and
intercontinental
transplantations — thus
increasing the chances of
patients finding better
matches
while
simultaneously significantly
reducing costs.
The difficulty with long-term
preservation of human
organs stems mostly from the
extensive tissue damage that
occurs when organs are cryopreserved, frozen at
temperatures of -320.8 degrees Fahrenheit. While
successful for single cells and simple tissues, the problem
is exacerbated with whole organs because of the multiple
cell types and other structures that react differently to
cold.
To combat these problems, Martin Yarmush, M.D., Ph.D.,
and Korkut Uygun, Ph.D., investigators in the Center for
Engineering in Medicine at Massachusetts General
Hospital (MGH), Boston, have developed a four-step
preservation technique that has tripled the amount of time
that rat livers can be stored before transplantation.
Key component of cell
division comes to light
The ability of microorganisms to overcome
antibiotic treatments is one
of the top concerns of
modern medicine. The
effectiveness of many
antibiotics has been
reduced by bacteria’s ability
to rapidly evolve and
develop strategies to resist
antibiotics.
Bacteria
achieve this by specific
mechanisms that are
tailored to the molecular
structure or function of a
particular antibiotic. For
example, bacteria would
typically develop drug
resistance by evolving a
mutation that breaks down
the drug.
Researchers at the Hebrew
University of Jerusalem set
out to determine if they
could predict a different
evolutionary process and
follow it in real time. Using
the quantitative approach
of physicists, the team
developed experimental
tools to measure precisely
the bacterial response to
antibiotics, and developed
a mathematical model of the
process. The model led
them to hypothesize that a
daily three-hour dose
would enable the bacteria
to predict delivery of the
drug, and go dormant for
that period in order to
survive. The research was
led by Prof. Nathalie Q.
Balaban at the Racah
Institute of Physics in the
Hebrew
University’s
Faculty of Science, working
with colleagues at the
Racah Institute, the Hebrew
University’s
Sudarsky
Center for Computational
Biology, and the Broad
Institute of Harvard and
MIT. The research paper,
“Optimization of lag time
underlies tolerance in
b a c t e r i a l
populations
evolved under
intermittent
antibiotic
exposure,”
appears in the
June 25 edition of
t
h
e
journal Nature.
To test their
hypothesis, the
researchers
delivered antibiotics to
bacterial populations in the
lab for precisely three hours
each day.
After only ten days they
were able to observe the
bacteria using a new
survival tactic. When
exposed to these repeated
cycles
of
antibiotic
treatments, the bacteria
evolved an adaptation to
the duration of the
antibiotic
stress
by
remaining dormant for the
treatment period.
The results demonstrated
that bacteria can evolve
within
days.
Most
significantly, it showed for
the first time that bacteria
can develop a biological
timer to survive under
antibiotic exposure.
To further test their
hypothesis, the researchers
delivered antibiotics for
different periods, exposing
three different bacteria
populations to repeated
daily antibiotic exposures
lasting 3, 5, or 8 hours.
Remarkably, each of the
populations adapted by
prolonging their dormant
stage to match the exposure
duration.
With
this
new
understanding of how
bacterial
populations
evolve survival strategies
against
antibiotics,
scientists could develop
new
approaches
for
slowing the evolution of
antibiotic resistance.
New light-sensitive protein enables
simpler, more powerful optogenetics
much more about their
functions. The neurons to
be studied must be
genetically engineered to
produce light-sensitive
p r o t e i n s
known
as
opsins, which
are channels
or pumps that
influence
electrical
activity
by
controlling the
flow of ions in
or out of cells.
Researchers
then insert a
light source,
such as an
optical fiber,
into the brain
to control the
selected neurons.
Such implants can be
difficult to insert, however,
and can be incompatible
with many kinds of
experiments, such as
studies of development,
during which the brain
changes size, or of
neurodegenerative
disorders, during which the
implant can interact with
brain physiology. In
addition, it is difficult to
perform long-term studies
of chronic diseases with
these implants. Mining
nature’s diversity: To find a
better alternative, Boyden,
graduate student Amy
Chuong, and colleagues
turned to the natural world.
Many microbes and other
organisms use opsins to
detect light and react to
their environment. Most of
the natural opsins now
used for optogenetics
respond best to blue or
green light.
Boyden’s
team
had
previously identified two
light-sensitive chloride ion
pumps that respond to red
light, which can penetrate
deeper into living tissue.
However, these molecules,
found in the bacteria
Haloarcula marismortui and
Haloarcula vallismortis, did
not induce a strong enough
photocurrent — an electric
current in response to light
— to be useful in controlling
neuron activity.
Mertesacker outburst reflects
Cameroon to investigate
World Cup match-fixing claims Germany’s great expectations
Costa Rica
defender
Miller out of
quarterfinal
The division of a cell in two
requires the assembly of the
mitotic
spindle,
an
extremely
complex
structure, which is the
result of the coordinated
action of a multitude of
proteins and a finely tuned
balance of their activities. A
large part of the time that a
cell requires to divide is
devoted to assembling the
mitotic spindle, which,
superficially, resembles a
ball of thread with the shape
of a rugby ball.
The
most
abundant
components of the spindle
are the microtubules. “By
labelling the ends of
thousands of these fine
filaments, which are
indispensable
and
extremely dynamic and
variable, we have finally
been able to follow their
distribution and movement
during the assembly of the
mitotic spindle,” explains
Jens Lüders, a cell biologist
from the Institute for
Research in Biomedicine
(IRB Barcelona). The
breakthrough appeared in
the advanced online edition
of the journalNature Cell
Biology.
“For more than 10 years we
have been able to track only
the growing ends of
microtubules but not the
starting points. As a result,
we
lacked
essential
information in order to
understand the dynamic
architecture of the mitotic
spindle and how it
contributes
to
cell
division,” says Lüders.
Headed by the German
scientist who runs the
Microtubule Organisation
group at IRB Barcelona, the
study carries only two
names, his own and that of
the French researcher
Nicolas Lecland, first
author, who completed his
PhD at IRB Barcelona
through a “la Caixa”
fellowship. The scientists
have demonstrated that the
protein ã-tubulin localizes at
the starting points of the
microtubule filaments and is
relatively stably associated
with these structures. Using
a version of ã-tubulin that
carries a fluorescent label
activated by laser light, the
researchers were able to
follow the movement of the
starting
points
of
microtubules within mitotic
spindles by filming dividing
human cells.
The Advanced Digital
Microscopy Facility, a joint
IRB Barcelona-Barcelona
Science Park Facility run by
the IRB physicist Julien
Colombelli, has been crucial
for
setting
up
the
technology required. “The
success of this study is also
the result of the technical
know-how and cuttingedge technology available,
without which we would
never have been able to
tackle
this
project,”
emphasizes Lüders. The
researchers describe for the
first time where most
microtubules form inside the
mitotic spindle, how they
develop, and how their
starting
points
are
transported — with the help
of three motor proteins — to
opposite poles of the spindle,
where
they
attach.
Simultaneous to this process,
the opposite ends of the
filaments extend towards the
cell centre, where they interact
with chromosomes. When the
spindle is finally assembled,
the microtubules pull the
chromosomes to opposite
poles and initiate the physical
division of the cell. “We now
have a more complete
understanding of how the
spindle assembles and
functions and can use our
novel marker for testing old
and new hypotheses about
underlying mechanisms,”
says the scientist.
Optogenetics, a technology
that allows scientists to
control brain activity by
shining light on neurons,
relies on light-sensitive
proteins that can suppress
or stimulate electrical
signals within cells. This
technique requires a light
source to be implanted in
the brain, where it can reach
the cells to be controlled.
MIT engineers have now
developed the first lightsensitive molecule that
enables neurons to be
silenced noninvasively,
using a light source outside
the skull. This makes it
possible to do long-term
studies
without
an
implanted light source. The
protein, known as Jaws,
also allows a larger volume
of tissue to be influenced
at once.
This noninvasive approach
could pave the way to using
optogenetics in human
patients to treat epilepsy
and other neurological
disorders, the researchers
say, although much more
testing and development is
needed. Led by Ed Boyden,
an associate professor of
biological engineering and
brain
and
cognitive
sciences at MIT, the
researchers described the
protein in the June 29 issue
of Nature Neuroscience.
Optogenetics, a technique
developed over the past 15
years, has become a
common laboratory tool for
shutting off or stimulating
specific types of neurons in
the
brain,
allowing
neuroscientists to learn
SPORTS
Salvador,
July
01
(Agency) : Cameroon are to
investigate claims that
seven of their players were
involved in match-fixing at
the World Cup, the
country’s
football
federation FECAFOOT said
on Monday.
FECAFOOT said it had
instructed
its
ethics
committee
to
probe
allegations of what it
described as “fraud” in
their three games in Brazil,
particularly a 4-0 loss to
Croatia in Manaus in their
second Group A game.
“Recent allegations of
fraud around Cameroon’s
three 2014 World Cup
games,
especially
Cameroon v Croatia, as well
the existence of “seven bad
apples (in our national
team)” do not reflect the
values and principles
promoted
by
our
administration,”
FECAFOOT said in a
statement.
“We wish to inform the
general public that, though
not yet contacted by FIFA
in regards to this affair, our
administration has already
instructed its Ethics
Committee to further
investigate
these
accusations.
“We
are
strongly
committed to employ all
means necessary to resolve
this disruptive matter with
the
shortest
delay,”
FECAFOOT’s
interim
president Joseph Owona
said.
The allegations against
Cameroon came from
convicted fraudster Wilson
Raj Perumal, who had
accurately forecast the result
and the fact a player would
be sent off in a discussion
with German magazine Der
Spiegel.
Cameroon midfielder Alex
Song was sent off before
halftime for a needless
elbow in the back of Croatia’s
Mario Mandzukic near the
halfway line, leaving his side
to battle with 10 men for the
majority of the game.
The game was also marred
by an incident near the end
when Benoit Assou-Ekotto
attempted to head-butt team
mate Benjamin Moukandjo.
Cameroon’s federation
subsequently launched an
investigation into the
incident but has yet to give
any update on possible
disciplinary action.
The latest controversy
adds to a long list for African
teams at the World
Cup. Both Ghana and
Nigeria, now out of the
tournament, were embroiled
in disputes over money in
Brazil.
Angry fans declare South
Korean soccer dead
Seoul, July 01 (Agency) : Disappointed South Korean fans have expressed their anger toward the national team as
it made its return home following an early exit from the World Cup in Brazil.
Local media showed clips of a fan throwing Korean traditional taffy candy, known as ‘yeot,’ at the players who had
lined up for a team photo at the international airport in Incheon on Monday. The thrower was heard as shouting “eat
yeot”; a common curse in South Korea.
Other fans also held up a banner designed in funeral style that said “South Korean soccer is dead!!” South Korea
finished last in Group H at the World Cup after defeats against Belgium and Algeria, and a draw with Russia. South
Korea was the last Asian team knocked out of the World Cup, leaving the continent without any representatives in
the knockout stages.
South Korea has been to nine World Cups, more than any other Asian team, but it has failed to build on its
performance as co-host of the 2002 World Cup, when it reached the semifinals.
Coach Hong Myung-bo, who was captain in 2002, apologized to fans for the team’s disappointing World Cup
performance.
Santo Andre, July 01 (Agency) : The
usually mild-mannered Per Mertesacker for
once lost his temper, his angry riposte
startling a German TV reporter who had
dared ask the defender why Germany had
laboured into the World Cup quarterfinals.
“What do you want from me? What do
you want?” Mertesacker snapped after
Germany’s 2-1 extra-time win over Algeria
on Monday. “We’re in the last eight and
that’s what counts.”
Mertesacker’s outburst epitomised the
frustration among the Germany players
who feel that, even with a victory, the fans
- and media - back home in Germany will
not be satisfied unless Joachim Loew’s
men dazzle and entertain.
Expectations in Germany are running
high for a team that has reached the semifinals of the last two World Cups - at home
in Germany in 2006 and in South Africa in
2010. This is the country’s “golden
generation” and the nation expects the title
- as do the players. The hapless ZDF
reporter had posed a question to
Mertesacker that some 30 million viewers
back home had wondered: why did the team
play so poorly?
“Do you think it would be better if we
played attractive soccer and got knocked
out?” the towering centre back continued
with uncharacteristic anger. “Do you think
that this is just a bunch of clowns here
playing in the last 16?
“I can’t understand all these stupid
questions right after a match,” “We worked
extremely hard for 120 minutes and fought
all the way to the end, and we played well
and won in extra time. It was a battle back
and forth the whole way. We played
courageously. Okay we let them have too
many chances but we didn’t give up a goal
when it mattered. We won deservedly.”
After Germany beat Chile 1-0 in a friendly
in March, the fans in Stuttgart jeered the
team off the pitch. Captain Philipp Lahm
said he understood their frustration.
“I can understand the fans, the people
paid for their tickets and they wanted to
see something,” Lahm said.
Belo Horizonte (Brazil),
July 01 (Agency) : Costa Rica
defender Roy Miller is out of
Saturday's World Cup
quarterfinal against the Netherlands with a muscle injury in
his left leg suffered during
training.
"The injury will keep him off
the pitch for several days," the
Central American nation's football association said of the 29year-old left back who hurt
himself practising penalties.
Costa Rica have been arguably the biggest surprise at the
World Cup, emerging top of a
group including Italy, England
and Uruguay with two wins
and a draw.
The 'Ticos' then squeezed
past Greece in a penalty
shootout after a 1-1 draw when
they were reduced to 10 men
following the sending-off of
defender Oscar Duarte.
Dutch team offered space trip if they win WC
The Hague, July 01 (Agency) : In an ‘out of the world’
incentive, a Dutch aerospace engineering company has
offered the entire Netherlands team a flight into space if
they win the World Cup. After finishing runners-up on
three occasions, the Netherlands are keener than most to
secure their elusive maiden World Cup title.
If that motivation is not enough for the players, this
year’s squad have been given an even bigger incentive
to bring the trophy home.
Dutch
aerospace
engineering
company
‘Ruimtevaartbedrijf SXC’, or SXC for short, have promised
the 23-man squad all a flight into space if they win their
maiden World Cup trophy, The Independent reported.
The offer is apparently inspired by Robin van Persie
‘taking flight’ to score his spectacular headed goal in the
5-1 thrashing of Spain.
“As a company of Dutch origin, we are mega proud of
the achievements of Oranje in Brazil. An unearthly
performance deserves an unearthly reward!” Co-founder
of SXC, Michiel Mol, told Dutch media. “We are going to
try to take the players literally to a higher level - 103 km!”
he said.
“(We’ll take) the whole selection of 23 players and of
course, Louis van Gaal,” Mol was quoted as saying.