B. Researchers Provide Relief for High Altitude Workers

Narrator: This is Science Today. If you've ever traveled to elevations of eight thousand feet or higher, you may have experienced altitude sickness. John West, a professor of medicine and physiology at the University of California, San Diego, says the body stores of oxygen are very small, so if a person is deprived of oxygen, symptoms including shortness of breath, fatigue and trouble sleeping set in.

West: It's not that the oxygen concentration decreases, but the total pressure decreases and therefore, the partial pressure of oxygen falls. And so the body just does not function as well.

Narrator: Because miners and astronomers are beginning to work more at high altitudes, West and his colleagues have developed a way to feed oxygen-enriched air into the workers' rooms using an inexpensive, rugged oxygen concentrator.

West: Now they've found that it's enormously valuable. Their efficiency is greatly increased; the level of fatigue is very much less. They can do much more physical work; they can sleep reasonably well, whereas they certainly couldn't before. And so it's the difference between night and day working at that high altitude.

Narrator: For Science Today, I'm Larissa Branin.

C. What to do When a Stroke Occurs

Narrator: This is Science Today. Acting fast can make all the difference when a stroke occurs. UCLA neurosurgeon John Frazee says the longer a patient waits, the more extensive the brain damage will be. Even if stroke symptoms subside, Frazee says it's important to get to the hospital.

Frazee: Because there may be something to prevent this from happening again - and happening in a permanent way. Many symptoms disappear in the first hour and that should be, nevertheless, a warning to the patient to go see somebody immediately as an emergency.

Narrator: A stroke is a 'brain attack' and is caused by a blood clot that cuts off oxygen to the brain and kills the tissue.

Frazee: If a patient comes in with a stroke and the -symptoms - paralysis, or speech problems, or vision problems have lasted more than an hour, the chances that they're going to recover in the next twenty-four hours is less than 14 percent.

Narrator: If treated on time - Frazee says new advances in stroke treatment can minimize brain damage, disability and death. For Science Today, I'm Larissa Branin.

D. An Exciting Area of Research in Bone Repair

Narrator: This is Science Today. Although the exact mechanisms of how bones heal are not quite clear, researchers at the University of California, San Francisco, have an idea bones heal very much the same way they form during fetal development. Jill Helms, an orthopedic surgeon at the university, says the crucial factor is blood vessel growth.

Helms: Bone is one of the most vascular tissues in the body and so it makes sense that its formation is intimately dependent on a good blood supply and more so than just tissues need blood to grow, but also the types of growth factors that are delivered by the blood supply to the developing bone are important.

Narrator: The researchers have been working successfully in the lab with one growth factor in particular called VEGF to help restore hard-to-heal bone tissue.

Helms: The area that VEGF has probably received the most attention recently is in cardiac repair and so there have been a number of clinical trials that have gone on. I think this is the new, very exciting idea that we might be able to use it in bone repair.

Narrator: For Science Today, I'm Larissa Branin.

E. Vitamin C is a Crucial Supplement for Smokers

Narrator: This is Science Today. If you smoke, the first bit of health advice is obviously to quit. But barring that, researchers have discovered even modest amounts of a vitamin C supplement could dramatically raise a smoker's level of this disease-fighting antioxidant. Lynn Wallock of the University of California, Berkeley says unlike previous studies, she and her colleagues at the U.S. Department of Agriculture separated the effects of diet and smoking on the level of antioxidants in the body.

Wallock: Both the smokers and the non-smokers were recruited for low fruit and vegetable intake. Virtually all of the constituents in the diet were similar, so what we were able to do was to isolate the effects of smoking.

Narrator: In doing so, researchers discovered that of all the antioxidants, only vitamin C was depleted by smoking and the smokers in particular had a very dramatic response to supplementation.

Wallock: But the message that we'd like to get across is that the supplementation was modest and that that could be achieved by improving the diet and the benefit of that is there are a lot of other helpful compounds in fruits and vegetables.

Narrator: For Science Today, I'm Larissa Branin.