A. Protease Inhibitors:
Powerful and Dangerous
Narrator: This is Science
Today. There's a new type of AIDS drug on the market,
called protease inhibitors, that have been receiving
a lot of attention lately.
Kahn: They have been used for short
periods of time, whether or not they will ever be
able to eradicate virus in combination with other
drugs is unclear, but they have developed a hype
about them that the AIDS epidemic is over. It clearly
is not.
Narrator: Dr. Jim Kahn of the University
of California, San Francisco says it's too early
to tell how effective they'll be over the long run,
but there's no denying they have the potential to
prolong life.
Kahn: They reduce disease progression,
they reduce virus, they help increase T cells, they
are a breakthrough in the treatment of HIV infected
people.
Narrator: On the downside, protease
inhibitors have severe side effects. Plus, people
who take them have to be incredibly disciplined
about it -- they literally can't afford to miss
one dose.
Kahn: Because if you don't take
enough of the medicine you won't get high enough
blood levels, and if you don't get high enough blood
levels the virus will replicate and will become
resistant.
Narrator: For Science Today, I'm
Steve Tokar.
B. To Prevent Cancer,
Stick to Fruits and Vegetables
Narrator: This is Science
Today. Take antioxidants and prevent cancer -- that's
the conventional wisdom.
Broaddus: And there's a lot of
evidence that people who eat a lot of fruits and
vegetables that contain antioxidants are more resistant
to cancer.
Narrator: But in the laboratory,
Dr. Courtney Broaddus of the University of California,
San Francisco fed antioxidants to lung cells that
had been exposed to asbestos, a powerful carcinogen.
The cells survived, but in mutated form -- mutations
that could lead to cancer. Broaddus says her results
help explain several other studies...
Broaddus: In which large numbers
of people who were heavy smokers or who had asbestos
exposure were given antioxidants on a daily basis
to see if it would help prevent their cancers. And
to the surprise of almost all physicians, this backfired
in the sense that those people who took the antioxidants
-- they actually developed more lung cancer than
the group that took the placebo.
Narrator: Broaddus says stay away
from big doses of antioxidant pills and stick to
fruits and vegetables. For Science Today, I'm Steve
Tokar.
C. Selenium Pollution?
Plant A Swamp
Narrator: This is Science
Today. Selenium is a problem around the world --
a toxic pollutant that poisons wildlife wherever
it collects. And it collects wherever there's heavy
industry or agricultural drainage containing pesticides.
Biologist Norman Terry says there are several ways
to clean up selenium, using plants that absorb it
and thus take it out of the ecosystem.
Terry: But perhaps the most interesting
aspect that our laboratory's concerned with is the
idea of volatilizing selenium.
Narrator: Volatilizing means turning
it into a gas. The best way to do that is plant
artificial wetlands, or swamps, containing plants
that are champion volatilizers.
Terry: We are interested in looking
at which plant species in wetlands are able to take
up selenium and volatilize it best. And by selecting
those species that do take up and volatilize selenium
the best, and planting wetlands with those species,
we may be able to increase volatilization.
Narrator: Scientists in Terry's
lab are also genetically engineering plants to improve
the rate at which they absorb selenium and make
it harmless. For Science Today, I'm Steve Tokar.
D. Teenage Birth Control:
Motivation Makes A Difference
Narrator: When teens
use birth control, motivation makes a difference.
This is Science Today. Dr. Philip Darney compared
three different methods of birth control among 400
teenagers -- condoms, the pill, and Norplant, a
contraceptive delivery system that's surgically
implanted in the upper arm. Darney found that the
teens who chose Norplant had a much lower pregnancy
rate -- zero, in fact -- than the teens using the
other two methods. He also found that Norplant users
tended to be older and more sexually responsible.
Many had already gone through an unwanted pregnancy.
Darney: We think we enrolled people
who were highly motivated to avoid pregnancy, and
they were willing to use this method that has a
lot of bothersome side effects -- it's a very safe
method but it has bothersome side effects like irregular
bleeding, sometimes acne, weight gain -- things
teenagers wouldn't like to have happen to them.
058 But they were so motivated to avoid, generally,
another unplanned pregnancy that they wanted to
use this method.
Narrator: Darney says family planners
should consider Norplant when recommending birth
control to teenagers. For Science Today, I'm Steve
Tokar.
E. Heredity and the
Risk for Alcoholism
Narrator: Why does
alcoholism run in families? This is Science Today.
In the 1980s, Dr. Mark Schuckit of the University
of California, San Diego tested over 200 sons of
alcoholics to see how sensitive they were to alcohol.
He found that 40 percent of them were unusually
insensitive -- meaning they had to drink more than
the average person to get drunk. When he looked
at the group ten years later...
Schuckit: What we found was, the
level of response to alcohol at about age 20 was
a very powerful predictor of alcoholism 10 years
later. Not perfect, but very powerful. If you were
a son of an alcoholic, and showed a low level of
response to alcohol, your risk for alcoholism almost
a decade later was 60 percent. If you were the son
of an alcoholic and showed a high level of sensitivity
to alcohol, your risk for alcoholism 10 years later
was about 15 percent, a huge difference.
Narrator: It may be another clue
to the riddle of why children of alcoholics are
at greater risk themselves. For Science Today, I'm
Steve Tokar.
