Health News
Stem Cells May Provide
Cure for Deafness
By: Madeline Ellis
Published: Friday, 3 April 2009
 Have
you ever passed by someone listening to their iPod so loud that you could
recognize the song playing? That person is probably doing irreparable damage
to their hearing. Continuous or repeated
exposure to loud noises can damage the small sensory cells in the inner
ear, called hair cells, which convert sound energy into electrical signals
that travel to the brain. Once damaged, hair cells cannot grow back and
there is no treatment—no medication, no surgery, not even a hearing aid,
that can fully correct a person’s hearing once it is damaged by noise. But
thanks to pioneering stem cell research, a cure for deafness could be in the
foreseeable future.
Researchers, led by Dr. Marcelo N. Rivolta of the University of Sheffield,
have been able to successfully grow early versions of the sensory hair cells
and neurons essential for hearing in the laboratory using stem cells taken
from the inner ear of discarded 9-11 week-old human fetuses. “The potential
is very exciting. This is a very important step forward. The hair cells and
neurons that give us the ability to hear are only produced during the
embryonic stage of development,” said Rivolta. “Once they are damaged or
lost, they do not regenerate. There is a clear need for a therapy that can
regenerate or replace them.”
“These cells would help us to develop the technologies needed to deliver
them into damaged tissues, such as the cochlea, in order to restore the
different cell types,” Rivolta said. “In the long term we all hope they may
offer a route to restoring hearing for patients.”
Though a treatment for deafness could still be a decade away, the cells
could be used more immediately to investigate the causes of deafness and to
test new drugs. “We have now an experimental system to study genes and drugs
in a human context,” said Rivolta. “The next step in our research is to
explore how these cells react when grafted into animal models.”
Rivolta’s research parallels work on the eye by another group of
British-based scientists, who plan to use stem cells to treat age-related
macular degeneration, a common cause of blindness, in clinical tests
starting in 2010 or 2011.
“This research is incredibly promising and opens up exciting possibilities
by bringing us closer to restoring hearing in the future,” said Dr. Ralph
Holme, director of biomedical research at the Royal National Institute for
Deaf and Hard of Hearing People, which helped fund the study. “There are
currently no treatments to restore permanent hearing loss so this has the
potential to make a difference to millions of deaf people.” About 500
million people worldwide and 28 million Americans are hearing impaired.
Given their unique regenerative abilities, stem cells offer exciting
possibilities for cures to such diseases as
Parkinson’s, diabetes, heart disease, cancer and
multiple sclerosis. Scientists are already using stem cells in the
laboratory to screen new drugs and to develop model systems to study normal
growth and identify the causes of birth defects.
Details of the research were published in the journal Stem Cells
and are due to be presented at a major stem cell conference in Oxford next
week.
Young Vegetarians Face
Greater Risk of Developing Eating Disorders
By:
Drucilla Dyess
Published: Friday, 3 April 2009
 The
practice of vegetarianism involves eating a diet that excludes meat, fish,
and poultry, while a variation of the vegetarian diet, known as the vegan
diet, also excludes eggs, dairy products, and honey. Following a properly
planned vegetarian diet can fulfill the nutritional needs of people of any
age and can even significantly lower risks of cancer and ischaemic heart
disease, as well as other diseases. However, vegetarianism has become
increasingly popular among teens for various reasons and may put them at
greater risk for the development of serious eating disorders.
A new study published in the April issue of the Journal of the American
Dietetic Association revealed that although young adult vegetarians
were less likely to be overweight or obese than were those who'd never been
vegetarians, about 20 to 25 percent of current and former vegetarians
demonstrated unhealthy behaviors for weight control. These
health-endangering practices include the use of diet pills, regurgitation,
laxatives, and diuretics, as well as binge eating.
According to lead researcher, Ramona Robinson-O'Brien, an assistant
professor in the Nutrition Department at the College of Saint Benedict and
Saint John's University in St. Joseph, Minnesota, “The majority of
adolescents and young adults today would benefit from improvements in
dietary intake. However, current vegetarians may be at increased risk for
binge eating, while former vegetarians may be at increased risk for extreme
unhealthful weight-control behaviors.”
She also advised, “Clinicians and nutrition professionals providing guidance
to young vegetarians might consider the potential benefits associated with a
healthful vegetarian diet, [but also] recognize the possibility of increased
risk of disordered eating behaviors.”
During the study, called Project EAT-II: Eating Among Teens, the researchers
analyzed data collected on 2,516 participants including teens and young
adults. Participants were grouped according to whether they were current,
former or non-vegetarians and each group was split into two sub-groups of
teens ages15 to 18 and young adults ages 19 to 23. The majority of the
vegetarians in the study were female.
The participants were questioned about whether or not they had experienced
binge eating, loss of control of eating habits, or extreme weight-control
behaviors. Around 21 percent of former vegetarian teens admitted to having
used unhealthy weight-control behaviors, compared to only 10 percent of
non-vegetarian teens. Among the young adults, extreme weight control
measures had been used by 27 percent of former vegetarians, 16 percent of
current vegetarians, and 15 percent of those never having been vegetarians.
The study also showed that binge eating and loss of control over eating
habits were reported by 21 percent of the teen vegetarians as well as 16
percent of former vegetarians, compared to only 4 percent non-vegetarians.
For the young adults, 18 percent of vegetarians reported binge eating and
loss of control compared to 9 percent of former vegetarians and only 5
percent of non-vegetarians.
Robinson-O'Brien said that although teens may view vegetarianism as a
healthy option, they could also be motivated by potential weight loss. She
explained, “Adolescents often experience a heightened sensitivity about
their appearance and pressure to conform to a cultural ideal, resulting in
body dissatisfaction and experimentation with various weight loss methods.”
HIV Drug
Treatment: Time Is of the Essence
By:
Neomi Heroux
Published: Thursday, 2 April 2009
 When
the AIDS epidemic began, any person with HIV present in their system was
facing a death sentence. There was no treatment, there was no cure.
Pharmaceutical manufacturers rose to the challenge and produced
antiretroviral drugs that reduced the virus from a killer to a chronic
disease.
One problem with treatment is deciding when to initiate therapy. Once
treatment began the patients would have to take the drugs for the rest of
their lives, and they were not without toxic consequences. Doctors and their
patients had to carefully consider the right time to take action. As
recently as five years ago HIV physicians would generally not recommend
beginning therapy for asymptomatic patients with a CD4 blood cell count
greater than 500 because of concerns about the drugs side effects.
A study released on April 1, that will appear in the April 30 issue of the
New England Journal of Medicine compared patients who started
treatment early, with those who delayed therapy. Lead researcher Dr. Mari M.
Kitahata, of the University of Washington, Harborview Medical Center,
Seattle said, “The optimal time to initiate therapy for asymptomatic
HIV-infected individuals has been unclear.” The study found that those who
delayed therapy increased their odds of dying by either 69 or 94 percent,
depending on how low the patient’s CD4 blood cell count was.
Kitahata’s team collected data on 17,517 American and Canadian HIV patients
who received treatment from 1996 through 2005. Patients were classified by
their CD4 immune T-cell count. The count is a measure of the immune system.
As the disease progresses the CD4 count drops. The participants were in two
groups, based on their CD4 counts, one group had counts between 350 and 500
cells per millimeter the second group was patients with CD4 counts above
500.
In the first analysis of 8,362 patients, 25 percent began therapy when their
CD4 counts from 350 to 500. The other 75 percent deferred treatment until
their CD4 counts fell below that. The patients who deferred treatment had a
69 percent greater risk of dying compared to those who began earlier
treatment.
In the second analysis of 9,155 patients, 24 percent began treatment at CD4
counts of more than 500 cells per millimeter. The other 76 percent delayed
treatment until their counts fell below 500, this group had a 94 percent
rise in risk of dying compared to the earlier therapy group.
Kitahata said, “Our study adds to the growing evidence that support earlier
initiation of therapy to improve survival. We think antiretroviral treatment
should be started when the CD4 count is above 500. I feel these data are
strong enough that I would start a patient who is ready and willing to begin
therapy at a CD4 count above 500 and certainly between 350 and 500.”
Dr. Paul E Sax, of the division of infectious diseases and the department of
medicine at Brigham and Women’s Hospital in Boston, said that the study does
seem to tilt the argument in favor of earlier treatment. It provides some of
the strongest data that earlier treatment prolongs survival. The study alone
doesn’t prove the point but adds to the accumulating data that earlier
treatment is preferred to waiting.
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