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November 02, 2005 - Image 5

Resource type:
The Michigan Daily, 2005-11-02

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November 2, 2005



University researchers restore auditory hair cells in deaf guinea pigs
By Rossitza lordanova U For the Daily


University scientists have made breakthrough
progress over the past several years in regener-
ating lost hair cells. Don't let the name fool you
though; this research won't help cure baldness - but
it will bring new hope to people suffering from hear-
ing loss.
Nearly 10 percent of the population in America suf-
fers from hearing loss, said Yehoash Raphael, a Uni-
versity professor of otolaryngology - the study of the
ears, nose and throat.
One of the causes of hearing loss is the lack of hair
cells in the ear. These hair-like cells - while contain-
ing structures called stereocilia that resemble tiny hairs
- don't have actual hair. They are in fact specialized
auditory cells that sense sound waves and transmit the
signal to the brain
Using previous research to guide them and deaf
guinea pigs as their subjects, Raphael and his associ-
ates have succeeded
in restoring popula-
tions of hair cells
""W e need in the ears of these
to work out One of the first
steps to developing
the details a way to restore hair
cell populations was
to make this for Raphael and his
research team to
C lin iCa||examine the devel-
opment of hair cells
app i Ca ein certain animals.
In order for a
but this is cell to become a
.tti ahair cell, it needs
not a triv il to express a gene
task and will called ATOH1. The
cells that do not
take a lot express ATOHI
become nonsensory
of work " hair cells.
research centers on
- Yehoash Raphael the insertion of the
University prof. of ATOH1 gene into
the non-sensory
otolaryngology at cells, turning them
the Medical School into hair cells in
In the 1980s,

other research
teams discovered
that birds were able to regenerate lost hair cells, coun-
tering the previous belief that this process was impos-
sible. The discovery motivated Raphael and his team to
further research this discovery.
Raphael laterdetermined that the new hair cells in
the birds were being generated from the nonsenso-
ry cells in the traumatized bird ear. This process of
change is called trans-differentiation.
But unlike birds, this does not occur spontaneously
in mammals. To accomplish trans-differentiation in a
mammal, Raphael and his associates needed to devel-
op a surgical technique and vehicle to introduce the
ATOH1 into the cells of a deaf mammal.
Raphael's team did this by inserting the ATOH1
gene in a virus that resembles the cold virus, but modi-
fied it to be nonreplicating and less recognizable to the
immune system.
Then they surgically introduced the gene-contain-
ing virus into the ears of deaf guinea pigs. After two
months, the animals were examined and new hair cells
were found in the ears.
"The hair cells weren't perfect, their hearing wasn't
perfect, but it is an improvement. And that is better
than nothing at all," Raphael said.
"We need to work out the details to make this clini-

cally applicable, but this is not a trivial task and will take a
lot of work."
Some of the research still left to perform includes apply-
ing the technique to different causes of hearing loss, deter-
mining if the newly regenerated cells can survive for long
periods of time, whether or not
long-term hearing loss can be
treated in the same manner and
understanding how this induced
change in cell identity occurs.
The research has other impli-
cations outside of alleviating
hearing loss. These hair cells
are also a vital part of a person's
sense of balance, Raphael said.
The hair cells in the ear help to
sense movement in the inner ear
and transmit that information
Yehoash Raphael to the brain in order to help the
person balance.
Raphael emphasized the
importance of his hair-cell research - older people are more
prone to losing their balance and falling, resulting in broken
bones that may never recover. There also aren't any medical
aids, like hearing aids, that will help a dysfunctional balance
In the future, Raphael hopes that treatment can be done
through a pill instead of surgery, which would be more cost
-effective and eliminate potential side effects.

TOP: A microscopic view of auditory hair cells in a healthy inner ear. BOTTOM: A
microscopic view of damaged inner ear of a deaf person, completely barren of any
hair cells.

Bush proposes $71 B to combat
future avian flu pandemics

Plan calls to buy enough
vaccine to protect 20
million from bird flu strain
WASHINGTON (AP) - President Bush out-
lined a $7.1 billion strategy yesterday to prepare
for the danger of a pandemic influenza outbreak,
saying he wanted to stockpile enough vaccine to
protect 20 million Americans against the current
strain of bird flu.
The president also said the United States must
approve liability protection for the makers of life-
saving vaccines. He said the number of American
vaccine manufacturers has plummeted because
the industry has been hit with a flood of lawsuits.
Bush said no one knows when or where a dead-
ly strain of flu will strike but "at some point we
are likely to face another pandemic."
The president, in a speech at the National Insti-
tutes of Health, said the United States must be pre-
pared to detect outbreaks anywhere in the world,

cines as new strains emerge, a process that now
takes months.
$583 million for states and local govern-
ments to prepare emergency plans to respond to
an outbreak.
Bush said a pandemic flu would be far more
serious than the seasonal flu that makes hun-
dreds of thousands of people sick ever year and
sends people to their doctors for a flu shot. "I had
mine," Bush said. Unlike seasonal flu, pandemic
flu can kill people who are young and healthy as
well as those who are frail and sick, he said.
He also said the United States was increasing
stockpiles of antiviral drugs, such as Tamiflu
and Relenza. Such drugs cannot prevent people
from catching the flu, but they can reduce the
severity of the illness when taken within 48
hours of getting sick, he said.
"At this moment there is no pandemic influ-
enza in the United States or the world, but if his-
tory is our guide there's reason to be concerned,"
Bush said. "In the last century, our country and
the world have been hit by three influenza pan-
demics, and viruses from birds contributed to all

"At some point
we are likely to
face another
- President Bush
and time to prepare," he said.
Bush said the cornerstone of his strategy
was to develop new technologies to produce
new vaccines quickly. "If a pandemic strikes,
our country must have a surge capacity in place
that will allow us to bring a new vaccine online
quickly and manufacture enough to immunize
every American against the pandemic strain,"
Bush said.
The principal goal of Bush's plan, Health

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