Sunday, November 28, 2010

New Uses for DNA Identification

It’s now possible to synthesize a nearly infinite number of unique DNA sequences. It’s also possible to identify the sequence of even a small sample of DNA quickly and cheaply. Taken together, these two advances are likely to lead to some interesting new uses of DNA technology.

According to an article in The New York Times, in Rotterdam, the Netherlands, police are experimenting with synthetic “DNA sprays” as a way to discourage robberies or to catch robbers of local businesses. When a store is robbed, the store clerk activates a security system that sprays the robber with a fine mist containing a unique synthetic DNA sequence as the robber departs. The system also notifies police that a robbery is in progress. Suspects who are apprehended within a certain time frame can then be tested for that specific DNA sequence.

Another idea: “DNA crayons” - each with a different DNA sequence - to mark valuable items that belong to you. Items suspected of having been stolen could then be tested and returned to their rightful owners. We’ll probably hear about other practical uses of DNA technology in the future. Have YOU got any good ideas?

Wednesday, November 24, 2010

Obesity and Body Size Misperception

According to a recent report in the Archives of Internal Medicine, about 8% of obese individuals don’t recognize that they need to lose weight. Researchers call the phenomenon “body size misperception”. Obese individuals who misperceive their body size tend to be more satisfied with their overall health and are more likely to believe that they have a low lifetime risk of chronic diseases related to obesity, than are those who acknowledge that they are obese. Two-thirds of them actually believe that they are at low risk of developing obesity in their lifetimes, even though they already ARE obese according to the standard government definition.

But are there other possibilities for these people’s failure to acknowledge their obesity besides body size misperception? Perhaps these individuals do know that they are obese, but because they don’t think they can lose weight or don’t want to try, they are unwilling to acknowledge it even on a survey. It’s called denial. Or perhaps they just don’t accept the current definition of obesity (a Body Mass Index of 30 or above) and/or its health consequences.

How people perceive obesity and its consequences need to be explored further if we wish stem the rising tide of obesity in the U.S. and around the world.

Sunday, November 21, 2010

Why is Global Warming Such a Hot-Button Issue?

Why can’t we hold a civilized conversation about global warming any more without the feeling that everyone’s minds are already made up? Some people argue that global warming is an established fact, and that human activities (most notably the burning of fossil fuels) are responsible. Others insist that the evidence in support of global warming is either not convincing, deliberately misleading, or even just plain false. It’s getting to be almost as bad as talking about abortion. How did it come to this?

One science writer suggests that part of the problem lies with a failure of climate scientists to communicate the meaning of scientific uncertainty adequately to the public. Predicting climate change far into the future IS an inexact science at the moment, but that does not mean that the climate isn’t changing. Not knowing everything is not the same as knowing nothing. I’m reminded of the common anti-evolutionist argument that evolution can’t be true because (gasp) “there are GAPS in the fossil record!”

In addition, scientists may sometimes come across as having a “we know best” attitude toward dissent, rather than a willingness to engage the dissenters in a dialogue. Scientists may need to acknowledge openly that there are things about climate change that they do not know yet. But rather than representing a failure of the scientific method, these uncertainties represent an opportunity to develop better methods and testable hypotheses so that in the future we CAN be more certain.

Thursday, November 11, 2010

Patenting Human Genes - An Update

In April of this year a U.S. District Court judge issued an order invalidating the patents on several human genes held by a company called Myriad Genetics (see "Human Gene Patents Invalidated.") The company promptly appealed, sending the issue to the next judicial level, the U.S. Court of Appeals.

Last month the U.S. Department of Justice filed a friend-of-the-court brief with the Court of Appeals, supporting the position that human genes should not be patentable. In its brief the Justice Department stated that “The chemical nature of native human genes is a product of nature, and it is no less a product of nature when that structure is ‘isolated’ from its natural environment than are cotton fibers that have been separated from cotton seeds or coal that has been extracted from the earth.” (The defendants in the case had tried to argue that their method of gene isolation had somehow fundamentally changed the genes, making them patentable.) However, in a bit of a compromise, the Justice Department’s brief also suggested that human DNA that is altered in some way (i.e. is not the original human gene sequence) could still be patented.

The U.S. Patent and Trademark Office has been issuing patents for human genes for years, but the legality of the patents has never been challenged in court. The outcome of the court case could affect the commercial use of numerous human genes and gene products. For now, we await the decision of the U.S. Court of Appeals.

Sunday, November 7, 2010

Alcohol and Caffeine - a Potent Mix

Last year the Food and Drug Administration sent warning letters to 27 manufacturers of alcoholic beverages containing caffeine (see this blog Nov. 15, 2009), asking the companies to justify the safety of their products. But apparently the agency has not yet followed through with its promises to review the safety information requested from the companies and then to take appropriate action if it was not forthcoming.

One of the companies selling caffeine-and-alcohol drinks was in the news again last month after students at two universities ended up in emergency rooms with alcohol poisoning. The drinks in question, called Four Loko, contain 23.5 ounces of 12% alcohol laced with caffeine. Allegedly the caffeine overrides the natural sleepiness effect of alcohol, causing the user to underestimate how drunk he/she really is.

The company says that it is being unfairly singled out.

Some college students will abuse alcohol no matter what form it is in. But are packaged caffeine-and-alcohol drinks GRAS (Generally Recognized As Safe) or not? It should be up to the FDA to decide, and so far it hasn’t.

Meanwhile, states and municipalities are taking action. Last Thursday Michigan became the first state to ban alcohol-and-caffeine drinks. The city of Chicago is considering a similar ban.

For more on this subject, go to a previous blog post titled "Caffeinated Alcoholic Beverages Under Scrutiny."

Monday, November 1, 2010

Assessing the Long-Term Risks of Drugs

Here’s a dilemma for you; drugs that prevent or treat chronic diseases and that therefore will probably be taken for the rest of the patient’s life are generally only tested for a only a couple of years (for safety and efficacy) before they are approved. What if the drugs have adverse effects that only become apparent when they have been taken for many years?

This concern has been raised recently by the discovery that two blockbuster drugs do in fact have long-term negative effects not seen in their initial safety studies. The class of drugs known as bisphosphonates (Fosamax, Actonel, and Boniva) widely used to prevent osteoporosis can, on rare occasion, lead to degeneration of the jawbone or to thigh fractures. And a drug called Avandia, often prescribed for diabetics to prevent heart disease, has been shown to increase the risk of heart disease in certain cases.

I'm not saying that FDA approval of these drugs in the first place was a mistake, because in some cases the benefits may still outweigh the risks. Still, it would be nice to know the long-term risks as soon as possible so that patient treatment decisions can be made with full information. The question becomes, then, how to reduce the potential long-term risk without making the drug approval process even longer than it already is. Requiring 30 years of clinical trials before a drug can be approved is clearly impractical.

Once a drug is approved, currently there is no method for effectively tracking the incidence of adverse side effects over time. Some health officials are suggesting that we develop a national drug-use database and require physicians to report all adverse effects, so that long-term effects can be determined as soon as possible. But that raises concerns over confidentiality of patient information.

What do you think?