Wednesday, August 22, 2007

No longer a cancer/youth tradeoff

This paper recently rolled off the presses touting p53 - that notable universal tumor suppressor gene that must be neutralized for cancer to proceed - actually has not only its usual cancer-resistance abilities, but potentially have youth-preserving ability when paired with a stabilizing protein, Arf.

This is pretty much counterintuitive to conventional wisdom; It's generally been accepted that getting old is a controlled mechanism to fight off the perpetual tumor generation going on in all of our bodies (you and I are likely killing a dozen or so tumor sites every day). In essence, you trade off maintaining your youthful looks and facility in order to live a long time. Not so, says this new paper!

Now, the sample sizes of some of the groups, especially in the somewhat dubious biomarker and biochemical studies seem quite small, and the fact they had to stoop to using a p value of 0.1 makes me veeeery leery. Still, I know keeping a dumb mouse alive for two years is no small feat, and direct comparisons are probably the only way to go here, so the t test suffers from the unpaired choices. Perhaps more worrying is their handwaving to dismiss the effect of the Ink genes, also known to have cancer-resistance properties. They seem to pull a 'Look over there!' moment towards the end of the paper.

All that said, there's some reasonable physiological evidence to make a story here, just probably not enough to topple the current hypothesis.

Finally, while this gene model keeps the mice youthful, still crossing that tightrope as if they were a spring whelp, it did not increase their life span. But ah, to die young after living a full life - doesn't seem so bad, eh?

Tuesday, August 07, 2007

The Fat of the Land

Angier weighs in on fat's defense.

This is an excellent example of a mechanism that got me interested in physiology in the first place. Fat should not be reviled, it is the amazing energy warehouse of the body, able to store more reserves that would otherwise tear our vital organs apart in a metabolic storm of fury.

Indeed, evolutionary biologists have proposed that our relative plumpness compared with our closest nonhuman kin, the chimpanzee, may help explain our relative braininess. Even a lean male athlete with a body fat content of 8 percent to 10 percent of total body mass (half the fat found on the average nonobese, non-Olympic American man) is still a few percentage points more marbled than a wild male chimpanzee, and scientists have suggested that our distinctive adipose stores help ensure that our big brains will be fed even when our cupboards go bare.

Too true. The brain is essentially a Ziploc bag full of fat and water, the additional white fatty matter affords male brains their excellent coordination. Fatheadedness is perhaps not such a terrible insult.

Fat also seems to know when it is getting out of hand, and it may resist new personal growth. Dr. Spiegelman and others have shown that with the onset of obesity — defined as 25 or more pounds above one’s ideal weight — the fat tissue starts releasing potent inflammatory hormones. That response is complex and harmful in the long run. But in the short term, said Dr. Spiegelman, “inflammation clearly has an anti-obesity effect, and it may be the body’s attempt to restrain further accumulation of adipose tissue.” The fat sizes up the risks and benefits, and it takes its fat chance.

Huh! If that's the case, it makes you wonder what effect the prolific amount of anti-inflammatory products we have on the market puts upon those bodies attempting to reign in their fattening bodies. Could aspirin be helping you put on the pounds?