X-Message-Number: 22668 Date: Sat, 11 Oct 2003 09:36:51 -0400 From: Thomas Donaldson <> Subject: CryoNet #22636 - #22643 Hi everyone! A few comments: 1. I too am not taken by all the concern with CO2. However if we go back far enough in the Earth's history the level of CO2 THEN is likely to bear little relation to the climate NOW. The reason is simple: the Sun, just like all other main sequence stars, slowly increases in brightness with age. Higher levels of CO2 may have helped the Earth maintain a similar temperature to its temperature now, and thus support life... as it does now. 2. With regard to Bill Warner's proposal and the recent discovery of ways to prevent cell's from losing their ability to divide: before we consider such events as major steps in our deterioration into old age and death, we must first establish that they ARE such major steps. To speak simply, other hormonal changes may first occur and kill us, before any direct issues of cell division play any role. If we don't deal with THOSE, then how well our cells divide becomes irrelevant. Not only that, but our aging probably results from a complex interplay of different factors. Our hormonal breakdown may block cell division by preventing the renewal of telomeres (just as an instance of how things MIGHT be related). If we want to deal with our aging, the best strategy is to use those drugs and treatments which are already known to increase lifespans while simultaneously working to understand, first, how our body comes to age. Calorie restriction and the efforts to understand how it works and duplicate it without limiting what we eat gives an example ... and one which will increase our lifespans, even if it does not completely eliminate aging. There are also a number of drugs which have been shown to increase lifespan, not in fruitflies or worms but in normal healthy mammals. These are generally rats and mice ... for no special reason other than that rats and mice live for a short enough time to make such experiments practical. And examination of these experiments often does NOT suggest that the drugs only improve health without increasing maximum lifespan. (Yes, I am disagreeing with those who argue that this result comes out statistically --- in some experiments). Best wishes and long long life for all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=22668