Program 916,
  November 15, 2005


A. A Technique that Differentiates Alzheimer's Disease from Another Dementia

This is Science Today. A non-invasive MRI technique that's called arterial spin labeling has been found to be as accurate as invasive scanning techniques in distinguishing between Alzheimer's disease and frontotemporal dementia. Norbert Schuff, who led the University of California , San Francisco study, says arterial spin labeling is a technique that basically measures the supply of blood flow in the brain.

Schuff: The beauty of this new technique is that it is entirely based on MRI techniques. So, you can easily attach it to the conventional MRI scan and in addition to that, we can measure the blood flow without any trace or injecting anything. Usually blood flow is measured by injecting some radioactive material or a dye.

Narrator: This technique's ability to distinguish between Alzheimer's disease and frontotemporal dementia is an important finding.

Schuff: At the early stage, those dementias are very difficult to separate. So, it will be very important to differentiate them at an early stage because they have different courses.

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

B. A New Approach Towards Understanding Degenerative Diseases

Narrator: This is Science Today. Researchers at the University of California , Santa Barbara have discovered a new approach to understanding the cellular processes of Alzheimer's and other degenerative diseases. Research scientist Ratnesh Lal, who led the study, says misfolded proteins in the cell membrane and changes in the electrical properties of cells, provide the explanation for the cell degeneration.

Lal: So all the effort in the last thirty-five years or so have been to see how the plaque causes the disease. So we are confident that you do not need the plaque to have the toxicity that you see in the cell. So then we're going to the actual cell level and show that indeed that's what happens.

Narrator: Understanding the basic cause of the formation of these plaques found in Alzheimer's and other degenerative diseases may lead to new therapeutics and diagnostic techniques.

Lal: So now the point is, you can control the activity of these structures by using chemicals and those chemicals are basically drug molecules.

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

C. Can Sunlight Help Prevent Skin Cancer?

Narrator: This is Science Today. Can sunlight help prevent skin cancer? While the issue is controversial, Daniel Bikle, a professor of medicine and dermatology at the University of California , San Francisco , says evidence shows this may be the case for some skin cancers.

Bikle: Sunlight, ultraviolet light is important for the production of vitamin D in the skin. We know from the work now that I've done and others, that the skin only makes this hormone from vitamin D that's produced in the skin, but it also responds to this hormone in terms of promoting differentiation. Well, the problem with cancer is it's a state where differentiation fails. So the question is, if people are not making vitamin D within their skin and not converting that vitamin D in the skin to this hormone, are they more susceptible to developing skin cancer from whatever cause chemicals or ultraviolet light?

Narrator: Bikle and colleagues at the San Francisco Veterans Affairs Medical Center will study this link further. For Science Today, I'm Larissa Branin.

D. National Lab Develops a Portable Radiation Monitoring System

Narrator: This is Science Today. In an effort to protect the nation from radiological or nuclear attack, physicists at the Lawrence Livermore National Laboratory have developed a portable radiation monitoring system. Nuclear physicist Dan Archer, says the Adaptive Radiation Area Monitor, or ARAM, can detect small amounts of radioactive materials from a distance and at speeds up to 60 miles per hour.

Archer: We developed the radiation detector system such that you could scan for radioactive material moving at highway speeds or pedestrian carry speeds or toll booth type speeds or packaged speeds on a conveyor belt, but the real novelty in this is being able to find very, very small amounts of radioactive material moving at sixty miles per hour down the road without ever having to slow the traffic down.

Narrator: The system was demonstrated successfully at Federal Express in Denver , and used to scan traffic in a major city. It has also been used as part of a larger network.

Archer: It's a commercially-available technology being used across the country, from coast-to-coast.

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

E. Bone Quality May Have More to Do with Fracture Risk than Bone Quantity

Narrator: This is Science Today. In trying to identify why aging bones become more brittle, researchers at the Lawrence Berkeley National Laboratory discovered it's not necessarily associated with bone density. Robert Ritchie, who also serves as chairman of Material Sciences at the University of California , Berkeley , led the study.

Ritchie: With age, the mineral density diminishes. So, in essence, there's less bone there and that was considered to be the reason why you were more prone to fracture. That theory is known as bone quantity. And it's clearly the case; you do lose bone with age. But there's been studies of late which have tried to look at the risk of fracture in people with the same bone density, but of different age groups and they found that there was not a perfect correlation.

Narrator: Ritchie studied bone of all ages and found that changes in bone quality , or how the bone resists to formation and growth of cracks, are what lead to breaks.

Ritchie: So, it's not to say that bone density is unimportant, but there's something else going on there as well.

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




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