Sunday, September 26, 2010

Thimerosal, Vaccines, and Autism

The tenth scientific study showing that autism spectrum disorders in children are not linked to thimerosal, a mercury-containing preservative once used in vaccines, has just been published in the journal of the American Academy of Pediatrics, adding one more to the nine others already published. In addition, the initial report that there is a link have been largely discredited. According to an article in the LA Times earlier this year, the doctor who first alleged that there was a link between autism and thimerosal has been rebuked by the British General Medical Council for the way his research was conducted, and the journal in which published his work declared that it should not have published the report.

And yet, one in four parents still persist in believing that vaccinations increase the likelihood of a child developing autism. Is there anything that could convince them otherwise?

Perhaps not. Resistance based on emotion (fear), may not be able to be overcome by scientific evidence, no matter how clear and convincing the evidence is. It’s too bad, really. It would be a shame if diseases like measles, mumps, or even polio made a comeback because not enough children had been vaccinated against them.

Wednesday, September 22, 2010

Testing Athletes for Gene Doping

Ever since winning athletic competitions has meant a lot of money, athletes have tried to increase their odds of winning by using performance-enhancing drugs. And for just as long, sports associations have tried to catch the athletes who cheat. In most cases the athletes have stayed one jump ahead by using newer-generation harder-to-detect “designer” drugs as soon as sports associations developed tests to detect the older-generation ones.

Sports associations and many athletes thought that the next level of sophistication in athletic performance enhancement through artificial means (i.e., cheating) was going to be “gene doping” – using genetic engineering techniques to introduce foreign genes into the body that would cause the body to produce performance-enhancing hormones naturally. But the athletes may have lost the detection battle before it even began. Scientists in Germany have already developed a test that they say can conclusively prove with 100% certainty that gene doping has occurred, using a blood sample as small as 200ul. The test looks for the presence of the foreign gene itself, not the protein or hormone product produced by the gene.

It’ll take about two more years for independent laboratories to validate the test, and so it may not be ready by the 2012 Olympics. But even if it’s not, blood samples could be stored and tested later.

Score one for the sports authorities, for once.

Monday, September 20, 2010

Biodiesel Fuel from Sunlight and CO2

From time to time I like to highlight innovations that have the potential to be real game-changers; good ideas still in the development stage that could alter our lives significantly within our lifetimes. So here’s one; a tiny start-up company called Joule Unlimited announced last week that it had received a patent on a bacterium that has been genetically engineered to produce diesel fuel using only sunlight, water and CO2. It’s similar to how plants produce hydrocarbons, but in this instance the hydrocarbon is diesel fuel, not a sugar or a starch.

The company expects that the process could be scaled up to produce 15,000 gallons of diesel fuel per acre, using water that is unfit for drinking (it could be wastewater or brackish water) and land that is unsuitable for farming. The process is not yet efficient enough to use the very limited amount of CO2 available in air (air is only 0.04% CO2), but it has been shown to work using the kinds of CO2 concentrations found in the effluent of coal-fired energy facilities. The company expects to begin production at a pilot plant in Texas by 2012.

Imagine a future in which the very CO2 that we’re trying so hard to get rid of these days (because it’s a greenhouse gas) becomes an asset – the raw material for creating diesel fuel. That would make CO2 an endlessly renewable energy source and solve most of the global warming problem at the same time.

With a few more good ideas like this, maybe there’s hope for our planet (smile).

Thursday, September 16, 2010

Electronic Cigarette Manufacturers Warned

The Food and Drug Administration (FDA) sent letters last week to five manufacturers of electronic cigarettes (e-cigs), warning the companies that they were making unsubstantiated medical claims about their products, including the claim that the products were an aid to stopping smoking – a medical claim prohibited by the Federal Food, Drug, and Cosmetic Act. The FDA also signaled its intent to regulate e-sigs as a drugs or drug-delivery devices.

An “e-cig” (since you forgot to ask) is a battery-powered cigarette-shaped device that can be loaded with a cartridge of nicotine and other additives. When the user inhales through the device, the battery vaporizes the liquid so that it can be inhaled into the lungs. The product contains no tobacco. A wisp of “smoke” appears, but it’s just water vapor.

Several of the e-cig products contain herbal ingredients in addition to nicotine. One of the e-cig companies even sells other drugs in liquid form for use in the devices, including an erectile dysfunction drug (tadalafil) and a weight-loss drug not approved in the U.S. (rimonabant).

The names of the companies and copies of the FDA’s letters to them can be found on the FDA web site in a press announcement dated Sept. 9th. Whether this is the end of e-cigs isn’t clear.

Monday, September 13, 2010

Stem Cell Research Continues (Temporarily)

In the long-standing battle between opponents and proponents of research involving stem cells derived from human embryos, last month a U.S. District judge issued a temporary injunction against the use of federal funds for such research (see this blog, Sept. 1). The injunction not only halted funding for future research projects that would have used stem cells derived from embryos, but also threw the funding for all current research projects into doubt. Researchers wondered whether their experimental animals would have to be euthanatized and their laboratory workers laid off.

To prevent that from happening, last week the U.S. Court of Appeals (the next step up the judicial ladder) issued a temporary injunction against the lower court’s ruling. The injunction will allow the National Institutes of Health to continue funding stem cell research temporarily, until an appeal is heard by the higher court. It also gives Congress time to act to change the law, but of course that depends on whether proponents of stem cell research can muster the votes to do so.

So now it’s in the hands of the U.S. Court of Appeals and Congress. Researchers, patient advocacy groups, and opponents of embryonic stem cell research will be watching closely. It’s time to lobby your congressman, if you have an opinion.

Wednesday, September 8, 2010

Pre-run Stretching Doesn't Prevent Injuries

I reported last year on this blog that the U.S.A. Track & Field association (USATF) was recruiting runners for a study to try to determine whether pre-run stretching prevents running injuries (see "Stretching and Sports Injuries"). Coaches and trainers often recommend stretching before exercise, but whether it’s helpful, harmful, or neutral has remained essentially an untested hypothesis.

To test the hypothesis that pre-run stretching reduces the incidence of injuries to runners, the USATF recruited 2,729 runners, defined as persons who ran over 10 miles a week. Each runner was randomly assigned to either a “stretch” or a “no-stretch” group. “No-stretch” runners were instructed not to stretch before running even if they had been in the habit of doing so before. “Stretch” runners were instructed to follow a specific stretch routine before running. All runners were instructed to continue their normal running routine for three months and to report any injuries that caused them to stop running for at least three days.

The results of the study were released last month. Just over half of the runners complied with their assigned group protocol and successfully completed the three months of the study. The results - injury rates were precisely 16% in both groups. In other words, pre-run stretching had no effect on injury rates.

One intriguing finding was that runners who normally stretched before running but were assigned to the “no-stretch” group had a higher injury rate than those who normally didn’t stretch and were in the same group. One hypothesis is that just changing their routine (stopping stretching) may have been enough to predispose them to injury.

So if you’ve always stretched before you run and like doing it, by all means keep doing it. But if you haven’t been in the habit of stretching before running, don’t feel that you have to start.

Sunday, September 5, 2010

Vaginal Gel is Effective Against HIV

Finally, there’s an HIV prevention method that’s controlled by women. This is especially important for women who are not in a mutually monogamous relationship and who cannot convince their men to use a condom. (In Africa, over 60% of HIV-infected persons are women who contracted the disease via heterosexual sex.)

In a study published last week in Science, nearly 900 sexually active women in a high-risk area in South Africa were supplied with either a vaginal gel containing the antiviral drug tenofovir, or just the gel alone as a control, over a thirty-month period. Women who received the drug were 39% less likely to become infected with HIV, compared to women in the control group.

Why wasn’t the treatment 100% effective? Part of the reason may be that some study participants may not have used the gel properly and consistently. Among women who used the gel as advised (both before and after sex) more than 80% of the time, the reduction in HIV infections was 54%. When the gel was used less than half the time the reduction in infections was only 28%. No one should be surprised; after all condoms, too, only work if you use them!

AIDS researchers are cheering. Although prevention wasn’t perfect, they’ve proved that pre-exposure prophylaxis controlled by women is at least partially effective. The next step will be to find more potent drugs or a more effective delivery method – perhaps a vaginal ring that releases the drug over longer periods of time.

By the way, would you like to know how the researchers monitored compliance to the study protocol (participant’s actual use of the gels)? They counted the used gel applicators returned by the women in the study and compared that number to the 181,340 gel applicators they gave out. Obviously the researchers suspected in advance that compliance might be a problem. You have to admire the researchers’ advance planning and their willingness to do what was necessary to improve the validity of their results.

Wednesday, September 1, 2010

Injunction Against Human Stem Cell Research

In March of 2009 President Obama issued an executive order permitting the use of federal funds for research on stem cells lines derived previously from human embryos, arguing that the researchers had not destroyed the embryos themselves. The Obama executive order effectively overturned the ban of the Bush administration on the use of human embryonic stem cells for research. At the time, I reported in this blog that the Obama order might still face a legal challenge, based on a federal law called the Dickey-Wicker Amendment of 1999.

Last week it finally happened. As the result of a lawsuit filed by several Christian groups and two doctors opposed to human stem cell research, a U.S. District Court judge issued an injunction which blocks the National Institutes of Health (NIH) from implementing the Obama order. The judge argued that the Obama executive order clearly violates the language of the Dickey-Wicker Amendment, and even some supporters of the Omama order grudgingly agree. According to Harvard ethicist Louis Guenin, allowing research on cell lines merely derived from human embryonic stem cells would be like allowing research on dead bald eagles. It’s illegal to kill bald eagles, and therefore anyone doing research on bald eagles killed by someone else would be considered complicit in the crime.

If research on stem cells derived from human embryos is to continue, it appears that Congress will have to overturn the Dickey-Wicker Amendment. Whether there are sufficient votes in both houses of Congress to do so is anybody’s guess. In the meantime, funding for future projects is on hold. And while NIH’s interpretation is that currently-funded research projects can continue for now, not everyone seems to agree. We’ll have to see how this one shakes out. For starters, I’m sure we can expect the ruling to be appealed.