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Stem Cell Problems
An interesting snippet in Nature demonstrated that increasing the expression of the p53 tumour suppressor genes can lead to accelerated ageing in lab mice. This is an important result. The conventional answer as to why cancers tends to increase in frequency as we age relies on the fact that much of the increase happens after reproductive maturity, and the notion thus arises that late-stage cancers tend to arise because there is no strong selection pressure to remove them. They are thus seen as merely incidental.
This snippet instead suggests that at least some of the processes that lead to cancer are part of the body’s defences against premature ageing. Some cancers may be simply the price we pay for living so damn long compared to many animals. This also problematizes some of the putative treatments for organ replacment or repair that involve adding lots of new stem cells, many of which have a higher probability to become cancerous than other body cell types.
I think a good parallel is with gout, where an unusually high serum level of urate crystals (approaching the solubility limit) leads to inevitable deposition of condensed crystals in joints and kidneys, leading to gout and kidney stones. Why have levels so high? Primates that diverged dozens of millions of years ago from the human lineage have much lower urate serum levels, but they don’t live as long. It turns out that urate is a highly potent scavenger of reactive oxygen. Thus gout is an evolved price we pay for extending our life spans and reducing the probability of genetic mutations that would lead to tumour growth.
p53 mutant mice that display early ageing-associated phenotypes
For both p53+/m and pL53 transgenic models, we propose that the early ageing phenotypes are in part a result of enhanced activity of wild-type p53 in some tissues. The reduced cellularity and mass in organs of the older p53+/m mice suggests that organ cell numbers are not maintained. Moreover, some of the ageing phenotypes suggest a reduction in proliferation of stem cells. With the ageing process, this proliferative reserve may decline more rapidly in the p53+/m mice as their stem cells undergo replicative senescence sooner than their p53+/+ counterparts. The accumulation of genetic insults in the stem cells of p53+/m mice may provoke enhanced arrest responses that gradually result in fewer division-competent cells. The p53+/m mice eventually reach a point in which the proliferative capacity of stem cells is so reduced that sufficient numbers of mature cells cannot be provided to maintain organ homeostasis. The resulting phenotypes may include reductions in organ mass, function and tolerance for stress.
No Batteries Required
Des sent me this: Shlomo, a Leeds Human Beatbox with a techno flavour.
Apparently, beatboxing is enjoying some kind of retro boost and the UK even has at least one booking agency devoted solely to this battery-free, instrument-free percussion. There’s even a pretty good website.
Not His Finest Hour
I saw a reference to a rather detestable HP Lovecraft poem, On the Creation of Niggers, but unfortunately the only extant verses I could find were slightly incorrect versions on Nazi sites like stormfront.org. I used Amazon’s “search inside the book” to get this from The Ancient Track: The Complete Poetical Works of H. P. Lovecraft.
When, long ago, the gods created Earth
In Jove’s fair image Man was shap’d at birth.
The beasts for lesser parts were next design’d;
Yet were they too remote from humankind.
To fill this gap, and join the rest to Man,
Th’ Olympian host conceiv’d a clever plan.
A beast they wrought, in semi-human figure,
Fill’d it with vice, and call’d the thing a NIGGER.
Ugh.
![In the afternoon we returned from school and saw the planes. We were all looking, not imagining about bombing. Then they began the bombing. The first bomb [landed] in our garden, then four bombs at once in the garden. The bombs killed six people, including a young boy, a boy carried by his mother, and a girl. In another place in the garden a women was carrying her baby sonshe was killed, not him. Now my nights are hard because I feel frightened. We became homeless. I cannot forget the bad images of the burning houses and fleeing at night because our village was burned](http://www.meehawl.com/Asset/Kid'sDarfur.jpg)
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