diver's dilemma
TRANSCRIPT
The last word–
ETERNAL YOUTH CLUBIn the 16th century, so the story goes,
the Hungarian countess Elizabeth
Báthory bathed in the blood of
young girls in a bid for eternal youth.
More recently we have learned that
the telomeres of our chromosomes
become shorter as we get older,
and this seems to be related to
ageing. Without wishing to condone
Báthory’s deplorable sadism,
if one were to take a blood sample
from an infant, store it perfectly for
50 years, then reintroduce it to the
body of the adult, could it have any
positive effect?
Not really. Even if we knew what role the shortening of telomeres plays in ageing, telomere transfusions could hardly help. Telomeres are repetitive sequences of base pairs that act as disposable buffers at the end of chromosomes. In somatic cells, the telomeres undergo shortening during division, shortening that in reproductive cells would cost genetically useful material .
Cells with long telomeres do nothing to protect other cells that have lost their own telomeres. Each telomere affects only its own end of its own chromosome in its own cell.
In reproductive cells such as oocytes and spermatogonia, a special enzyme called telomerase extends the telomeres to a good starting length.
The process continues at least to the early stages of embryonic development and persists in some classes of stem cells. In particular, most blood cells are short-lived, so they have to be continually replenished from stem cells in the spleen, marrow and so on. This means a frozen autograft from these structures might serve to replace the stem cells of some critical tissues late in life, but blood transfusion would not. Stimulating telomerase production might work better, but it also could be risky because this is how some kinds of cancers survive.Jon RichfieldSomerset West, South Africa
There are really two separate questions here. The first is, what are the causes of ageing? Telomere shortening is one theory but it can’t really explain ageing because many animals such as the nematode worm age and die without undergoing cell division at all. Conversely, cancerous cells can effectively be immortal, undergoing thousands of cycles of cell division without any reduction of potency. Ageing is a complex interplay of many different phenomena including a gradual decrease in mitochondrial function because of oxidative stress and the build-up of misshapen proteins resulting from transcription mistakes and accumulated DNA damage.
The second question is whether a transfusion would work. The answer is no. Replenishing “aged” blood with “young” blood would not ameliorate any of the cellular phenomena that lead to ageing. The most probable outcome would be negative:
the person involved would quickly become sick after the transfusion because the replaced blood would lack the circulating antibodies that the individual had built up over the preceding 50 years. As a result, germs that had not been a problem prior to the transfusion would suddenly find a new and easy target in the new blood circulating through the body.Allan LeesChief information officerBuck Institute for Age ResearchNovato, California, US
THIS WEEK’S QUESTIONSThirsty jets
Last month, on a flight from London to Washington DC, the Boeing 747 I was flying on had to wait a little while for take-off on the runway at Heathrow. It was a very wet day and I noticed that the engines appeared to be sucking up water from the tarmac in front of them. Strangely, the water rose vertically in a very narrow stream less than 10 centimetres wide from a point on the tarmac directly in front of each engine. Then, when the vertical columns of water reached a point about a metre in front of the centre of each engine, they changed direction to head horizontally into the middle of each turbine. They looked, in effect, like large walking sticks made of water pouring upwards into each engine. I can accept that jet engines suck in huge amounts of
water on wet days but presumed they did it more generally from the air around them rather than somehow sucking it up vertically from the tarmac in such a specific way. What is going on?Jennifer GoldMadrid, Spain
Closing time
Why do some flowers close at night? What is the evolutionary advantage of doing this, and why do only some plants bother to do so?Craig Christchurch, New Zealand
Diver’s dilemma
On a recent scuba-diving course, the instructor took a plastic bottle down to a depth of 30 metres, filled it with air from an oxygen tank and screwed the cap back on. As he predicted, back at the surface the sealed and now highly pressurised bottle seemed very light. Sure enough, when he released the air at the surface the bottle seemed heavier. Surely this was just an illusion? The pressurised air added at depth should have added weight to the bottle, rather than reducing it. If it was an illusion, how are people so easily taken in by suggestions like this? And if it wasn’t, what was going on? John GavinLondon, UK
Dead in space
During long voyages in space it is possible that people will die, either from illness or because of an accident. What plans are there for disposal of the corpses?Jessica Franklin (age 12)London, UK
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“Stimulating telomerase
production is risky – this is
how some cancers survive”
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“Germs would suddenly
find a new and easy target
in the transfused blood”