Wednesday, December 15, 2010

Why Did Swine Flu Kill Healthy Adults?

One of the most intriguing questions about the swine flu epidemic last year was why most of the deaths occurred in healthy young adults. Why were the very young and the very old generally spared?

A recent paper in Nature Medicine provides a clue, according to a news article in Science magazine. The gist of it is that the immune system of most adults is not very effective against first exposure to the H1N1-type virus. Unable to kill the virus initially with just a normal first immune response, the immune system in some patients mounted an all-out “do or die” effort to kill the virus. The result was a severe inflammatory reaction in the lungs that ultimately killed the patient instead of the viral infection.

The theory of a hyperactive but ineffective immune system would explain why the very young and the very old were spared by swine flu. The very young do not have a fully developed immune system with which to mount even a normal immune response, much less an exaggerated one. And many older persons may have had at least some effective antibodies against H1N1 by virtue of having been exposed to the previous H1N1 strain that was around until the late 1950’s.

Sunday, December 12, 2010

Does Aspirin Reduce the Risk of Cancer?

In addition to its known blood anticoagulant properties, aspirin might also help prevent cancer, according to an article published in the Jan. 1, 2011 issue of The Lancet. The authors of the study examined past data from the medical charts of over 25,000 patients in eight different studies who were taking aspirin to reduce their risk of a cardiovascular event. They found that daily doses of at least 75 mg of aspirin for at least five years reduced the overall death rate due to cancer by an astonishing 21%.

So should we all start popping aspirin? Not necessarily, says the Deputy Chief Medical Officer for the national office of the American Cancer Society in his blog post of Dec. 6. Although he finds no fault with the reported results as an interesting observation, he points out that the study was a retrospective (in the past) examination of cancer deaths in studies originally designed for other purposes – far better would be a randomized prospective (looking into the future) trial, in which both the risks and benefits of aspirin could be studied together. But such a study would take another 20 years! Who wants to wait that long?

It’s a quandary often faced in medicine – what to do when there’s tantalizing new information that seems to point in a certain direction, but no way to know for sure. No doubt, some of you will be tempted to start taking aspirin as a result of this new study. Before you do, consider carefully that taking aspirin may be a double-edged sword; risks associated with taking aspirin include (in some people) gastrointestinal bleeding and bleeding in the brain. Doctors don't generally recommend aspirin for cancer prevention in healthy persons.

Wednesday, December 8, 2010

Cellulosic Ethanol? Not Any Time Soon

Old conventional wisdom: ethanol made from farm and forest organic wastes (cellulosic ethanol) would soon be powering our cars and trucks. New conventional wisdom: cellulosic ethanol is dead, at least for now.

Not five years ago the government was pouring money and tax credits into various cellulosic biofuels projects. Although there were technical hurdles still to be overcome in extracting ethanol efficiently from cellulose and lignin (the primary energy storage molecules in most plants), there was optimism that the problems would be solved in short order. Today, plans for large-scale demonstration plants have been shelved, venture capital has dried up, and the industry is producing just 10% of the production goal once set by the Environmental Protection Agency. What happened?!

Lots of things happened, it turns out. Ethanol production from corn (technically easier) increased four-fold and is at an all-time high. Oil got cheaper again, technical problems in producing ethanol from cellulosic feedstocks have not yet been overcome, and investors are worried that government support (i.e., subsidies) for the developing cellulosic biofuels industry may dry up. Unless something changes, don’t expect to hear much about cellulosic biofuels for a while.

Sunday, December 5, 2010

Dinosaur Proteins Found in Fossils

Paleontologists have generally assumed that the only useful information that could be obtained from ancient fossils was in the sizes and shapes of the organism’s bones. The prevailing view has been that the soft tissues and any organic molecules or cellular structures within the bones themselves would have long since disappeared, leaving behind only fossils comprised of the same minerals found in rocks.

That view is slowly changing. It now appears that under the right conditions of fossilization, organic molecules may still remain in some fossils. So far, researchers have identified molecules that appear to be collagen and even fossilized osteocytes (bone-forming cells) and red blood cells, from the bones of dinosaurs as old as 80 million years.

No one is suggesting that we could ever resurrect dinosaurs from these ancient materials – cloning dinosaurs is still in the realm of science fiction. However if we could identify the precise sequences of certain ancient proteins, we’d have a better understanding of the function of these proteins within the organism. We might also be able to more accurately map out the evolutionary relationships between organisms, both ancient and living.

Reference: Schweitzer, Mary. Blood From Stone. Scientific American Dec. 2010, pp. 62-69.