A.
The FDA Plans to Closely Scrutinize Certain Herbal
Products
Narrator:
This is Science Today. The Food and Drug Administration
will be looking more closely at the effects of certain
herbal products, including those containing aristolochic
acid or aristolochia. These are marketed to combat
weight loss and alleviate gastrointestinal problems,
but have been linked to kidney failure and cancer.
Unlike drugs, herbal supplements do not need FDA
approval before becoming available to consumers.
Gold:
Herbal and other dietary supplements have a separate
law, which govern them. That law doesn't allow FDA
to require testing in advance the way it does of
pharmaceutical drugs.
Narrator:
Lois Swirsky Gold directs the Carcinogenic Potency
Project at the University of California, Berkeley.
While the FDA did ban the importation of products
containing aristolochic acid, these products were
still easily available on the Internet. In a medical
journal, Gold publicly called on the FDA to come
up with better regulations.
Gold:
It raises the question of how well are people
protected about taking herbal supplements.
Narrator:
For Science Today, I'm Larissa Branin.
B.
Tai Chi Found to Improve Health Functioning in Older
Adults
Narrator:
This is Science Today. A UCLA study following older
adults taking a 16-week Tai Chi class, reported
a significant boost in shingles immunity. The class
used a variant of the meditative martial art called
Tai Chi Chih, which is specially designed for easy
use by older adults. Study leader Dr. Michael Irwin
says Tai Chi Chih also improved health functioning.
Irwin:
What I mean by health functioning is the ease at
which people go about their day-to-day activities
- walking upstairs, carrying packages and simply
walking. The practice of Tai Chi produced the greatest
improvements in the individuals who had the greatest
declines of physical functioning upon entry into
the study.
Narrator:
The next step is conducting a larger study.
Irwin:
We have a current study ongoing supported by the
National Institutes of Aging and the National Center
for Complimentary and Alternative Medicine that
will replicate these findings and to evaluate whether
these changes in improvements of immune function
and health functioning are sustained over time.
Narrator:
For Science Today, I'm Larissa Branin.
C.
Understanding What Goes Wrong in Bacterial Meningitis
Narrator:
This is Science Today. Bacterial meningitis is one
of the most serious infectious diseases and can
affect patients of any age. Dr. Victor Nizet, a
pediatric infectious disease expert at the University
of California, San Diego, says it develops as a
complication of bacteria circulating in the bloodstream.
Such bacteria circulation is not uncommon.
Nizet:
But our white blood cells and the filtering
activity of organs such as the liver and the spleen
will remove these bacteria from the circulation,
so that we have no harm.
Narrator:
But some pathogens establish higher levels in the
bloodstream and may have a property to penetrate
across the protective blood-brain barrier. Nizet
is working to decipher just how this occurs.
Nizet:
We developed a model of the human blood-brain
barrier, in which capillary endothelial cells were
isolated from a human patient, immortalized, and
maintained in the laboratory, so that we could directly
study interactions between bacteria and these cells
that represent your blood-brain barrier.
Narrator:
For Science Today, I'm Larissa Branin.
D.
The Predictive Value of the PET Scan in Alzheimer's
Disease
Narrator:
This is Science Today. A PET scan is a functional
imaging measure in which the brain and its metabolic
pattern may be viewed in three dimensions. UCLA
researchers have found that the use of PET scans
improves doctors' ability to predict Alzheimer's
disease accurately. Dr. Dan Silverman, associate
director of imaging at the UCLA Alzheimer's Disease
Center, studied the results of PET scans taken between
1991 and 1999 of patients with mild cognitive complaints.
Silverman:
What we found is that this prediction of the
physicians went from 66 percent of the time being
correct in patients whom they thought had a stable
condition, to 96 percent of the time being correct,
that the PET scan also were negative for having
any one of those kind of conditions. On the other
hand, if the PET scan were positive, it was 18 times
more likely that they would actually have a progressive
condition than if the PET scan was negative, just
among these patients who the doctors referring them
thought had no progressive dementia present in their
brains.
Narrator:
Spotting Alzheimer's through metabolism patterns
on PET scans has been inferred in previous research,
but this is the first study to show it works in
practice. For Science Today, I'm Larissa Branin.
E.
Using Mars to Understand Global Climate Change
Narrator:
This is Science Today. When it comes to studying
global climate change, one of the most important
aspects is to know how the atmosphere has been affected
by human activities. To know that, one needs a record
of what a human-less atmosphere looks like and how
it works. Mark Thiemens, a researcher at the University
of California, San Diego, says in this respect,
Mars makes a nice case study.
Thiemens:
You can study a more simple system. No people, no
ocean, no life and so understand that part of atmospheric
cycles, that when we look at our own perturbed atmosphere,
we have another tool kit. And the reverse is true
when we study Mars. We know from our studies of
atmospheric samples on Earth, we can apply that
same knowledge to the Mars case. So, it works both
ways.
Narrator:
Thiemens and his colleagues have been examining
Martian meteorites to gain insight into the evolution
of the Martian atmosphere.
Thiemens:
The meteorites we get and analyze have come
from different times in Martian history, so by looking
at those, one has sort of a snapshot of what's happened
over time in the Martian atmosphere.
Narrator:
For Science Today, I'm Larissa Branin.
