Public health, defense, what will *really* make us safer

I generally don’t discuss a lot of politics on here. It’s not that it’s a topic I’m uninterested in; it’s just that, for the most part, other people do it so much better than I do, so I leave a lot of it to them. There are, of course, exceptions. Intelligent design is much more of a cultural and political issue than a scientific one, despite the protestations of its advocates. There are others that occupy a similar niche. The idea that abortion causes breast cancer, for example, is one that has made its way into information packets that must be given to women contemplating termination of their pregnancy in a number of states, despite the actual science of that “connection” being refuted by a number of large studies. It’s no longer a scientific issue; it’s a political one.

Alas, this is the case with our health as well. And despite the lip service paid to making this country “safer” in the aftermath of 9/11, the measures put in place show that protection of our health has become almost exclusively a political issue, and the science is again being ignored.
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If a way to a man’s heart is through his stomach…

…be prepared to take some disinfectants along for the ride.

One thing that is a total geek-out for me is reading about ecology. It’s one of the areas I wish I’d taken more coursework on back in college. At the time, it didn’t much interest me–studying species interactions was boring, and molecular biology was much more interesting. I’ve pretty much flipped 180 degrees on that one. (Well, molecular biology isn’t boring, but it’s moved off its rung as a top interest). My main interest as far as ecology is concerned is microbial ecology–especially of the ecosystem we like to call human beings. I’ve discussed bacterial ecology a bit previously (see here, here, and here, for instance), and a new study is once again making us reconsider what we know about our own personal microbial flora.
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New Grand Rounds at GruntDoc

For anyone unfamiliar with Grand Rounds in the blogosphere, it’s a medical blog carnival. With posts submitted by doctors, patients, and generally medically-interested readers, there’s usually a little something for everyone. This week’s edition is located over at GruntDoc (you can read some background on GruntDoc at “Pre-Rounds” here–requires free registration.) Lots of good posts this week as usual. A few that caught my eye: a post a Parallel Universes discussing a recent Lancet paper on iron supplementation and malaria; some commentary at Red State Moron on prenatal diagnosis and termination of pregnancy: are patients getting the right information, and are they pressured one way or another by their OB/GYN?; and a discussion of the hedgehog pathway in obesity and osteoporosis over at The Biotech Weblog (which was also mentioned here at afarensis).

Mechanism of malaria “hide and seek” coming into view

Malaria is one of mankind’s oldest known killers, with descriptions of the disease dating back almost 5000 years. Each year, malaria causes 300-500 million infections, and up to 3 million deaths–about 5000 Africans die of the disease every day; one child succumbs every 30 seconds. The disease is caused by a number of species of the Plasmodium genus. (In humans, malaria is almost always caused by one of four species: Plasmodium vivax, Plasmodium ovale, Plasmodium falciparum, and Plasmodium malariae, with P. falciparum causing the most severe disease). Unlike many pathogens I discuss on here, Plasmodium is a protozoan–a eukaroyte with a nucleus, like you and I. It also has a very complex life cycle, going through different stages in its mosquito and vertebrate host. (I presented a short overview of this previously in this post on potential malarial vaccines). Though vaccines may be available in the future, prevention today is largely via control of the mosquito vectors using insecticides and mosquito netting. However, mosquitoes are growing increasingly resistant to the insecticides, and many people living in at-risk areas lack the financial means to purchase bed nets.

There are anti-malarial drugs to treat the patient once they’ve already been infected, but these, too, are losing their effectiveness due to parasite evolution. Additionally, a single infection does not confer life-long immunity. Not only can an individual be infected with different species of Plasmodium, but the parasite can switch the antigens it presents–the proteins on the parasite surface that the immune system recognizes. A recent study published in the journal Nature sheds some light on just how P. falciparum switches these antigens.
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Are female night owls screwed?

As I write this at 2AM sitting under annoying fluorescent lights, am I increasing my risk of developing breast cancer? Maybe, according to a recent study showing that melatonin-depleted blood can spur the growth of mammary tumors:

The increased breast cancer risk in female night shift workers has been postulated to result from the suppression of pineal melatonin production by exposure to light at night. Venous blood samples were collected from healthy, premenopausal female volunteers during either the daytime, nighttime, or nighttime following 90 minutes of ocular bright, white fluorescent light exposure at 580 µW/cm2 (i.e., 2,800 lx). Compared with tumors perfused with daytime-collected melatonin-deficient blood, human breast cancer xenografts and rat hepatomas perfused in situ, with nocturnal, physiologically melatonin-rich blood collected during the night, exhibited markedly suppressed proliferative activity and linoleic acid uptake/metabolism. Tumors perfused with melatonin-deficient blood collected following ocular exposure to light at night exhibited the daytime pattern of high tumor proliferative activity. These results are the first to show that the tumor growth response to exposure to light during darkness is intensity dependent and that the human nocturnal, circadian melatonin signal not only inhibits human breast cancer growth but that this effect is extinguished by short-term ocular exposure to bright, white light at night. These mechanistic studies are the first to provide a rational biological explanation for the increased breast cancer risk in female night shift workers.

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