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A.
Improving Methods of Dealing with Research Animals
Narrator:
This is Science Today. The University of California
Center for Animal Alternatives is a systemwide center
dedicated to improving methods of dealing with animals
in research, education and testing. Lynette Hart,
who directs the center, says there are many ways
this can be accomplished.
Hart:
Including replacement alternatives, but also just
refining the way we care for animals. Husbandry, improving
all aspects of animal care, utilizing more alternatives
for teaching so that fewer actual animals are used.
Narrator:
This includes state-of-the-art software programs and
other specimens, which are used by students and faculty
at the UC Davis School of Veterinary Medicine to study
comparative anatomy.
Hart:
Each week, they have one hundred different kinds of
specimens and microscopic slides and different things
that are actually very tactile that they can examine
during their laboratory each week. We're using these
kinds of specimens that are reusable, rather than
having to kill any animals for that purpose.
Narrator:
For Science Today, I'm Larissa Branin.
B.
Reducing Carcinogenic Chemicals Produced While Grilling
Meats
Narrator:
It's barbecue season, so now's a good time to think
about healthy cooking. This is Science Today. Researchers
have long been studying carcinogenic chemicals called
heterocyclic amines, which result from over-cooking
beef, pork, poultry and fish at high temperatures.
In fact, scientists have identified 17 different heterocyclic
amines that may pose a human cancer risk. Mark Knize,
a biomedical scientist at the Lawrence Livermore National
Laboratory, has been studying these chemicals.
Knize:
In fact, one of them that we isolated and identified
here at the Lawrence Livermore Lab actually causes
breast cancer in female rats and colon cancer and
prostate cancer in male rats and those are just the
kinds of cancers that people on a Western sort of
a diet, which is high in meat, high in fat - those
are the kinds of cancer they get.
Narrator:
Knize and his group discovered that altering
your cooking preparation may dramatically reduce production
of heterocyclic amines.
Knize:
There
are several things you can do - flip the meat every
minute, or microwave first for one and a half minutes
or two minutes and then cook it. Or you can marinate.
All these things affect the amount of the hertocyclic
amines and it seems a good idea to reduce your exposure.
Narrator:
For Science Today, I'm Larissa Branin.
C.
Research Links Evolution of Bird Flight to Advanced
Parental Care
Narrator:
This is Science Today. A new theory on the evolution
of bird flight suggests advanced parental skills led
former ground-dwelling reptiles to the trees where
they could better nurture their young. James Carey,
an ecologist at the University of California, Davis,
says until now, there have been two basic theories
on the evolution of bird flight: the cursorial, or
ground-to-tree theory and the arboreal, or tree-to-ground
model.
Carey:
My feeling was that neither one of these theories
really rang true. I decided to look into the evolution
of birds and when I got in this literature, it's basically
contrasting what's the difference between reptiles
and birds - and that is that the first impression
would be that birds can fly and virtually no reptiles
can.
Narrator:
Carey proposes that the evolution of feathers
was linked to parental care, as was the beak.
Carey:
Out of all the literature, including the theories
of the arborial and cursorial theory, the beak has
been ignored. Basically, advanced parental care involves
provisioning with a point source. The beak is basically
a point source for provisioning food to the young.
Narrator:
For Science Today, I'm Larissa Branin.
D.
How Mild Concussions May Affect the Developing Brain
Narrator:
This is Science Today. Researchers at UCLA have found
that mild traumatic brain injury may impair the ability
of a child's brain to develop to its fullest potential.
Dr. David Hovda, director of UCLA's Brain Research
Center, says the reason behind this loss may be related
to an interference with the regulation of the brain's
NMDA receptors.
Hovda:
This NMDA receptor has been altered. And so by
blocking it to protect the cells from dying, you may
be actually retarding the ability of the brain to
recover its plastic response.
Narrator:
A
plastic response refers to the brain's ability to
experience ongoing growth. Hovda says the majority
of mild concussions may not cause that much of a deficit.
Hovda:
However, if the injury is severe enough that it could
actually cause a disruption for weeks to months, then
there may be a critical period of time when the brain
will not be able to take advantage of either new educational
opportunities or new experiences.
Narrator:
For Science Today, I'm Larissa Branin.
E.
Living Wills: Is the Policy Ahead of the Science?
Narrator:
This is Science Today. Over the last decade, there's
been a major push in this country to advocate the
use of advance directives - or living wills - but
according to Peter Ditto, a psychology and social
behavior professor at the University of California,
Irvine, the policy has gotten ahead of the science
Ditto:
Every major medical organization suggests that people
should complete these, but nobody had really looked
to see whether they accomplished the things that they
were supposed to accomplish. Can people really make
decisions for a future self that's very different
from where they are now? Can other people understand
people's wishes?
Narrator:
According to Ditto's findings, the answer is -
not really.
Ditto:
Now that doesn't mean that a longer-term discussion
or some other sort of intervention might not do better,
but it means that the simplest version of this isn't
working the way that advance directives aren't accomplishing
what they're supposed to accomplish.
Narrator:
For
Science Today, I'm Larissa Branin.
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