X-Message-Number: 26367
Date: Tue, 21 Jun 2005 18:22:44 -0700 (PDT)
From: Doug Skrecky <>
Subject: 180'th update on fly longevity experiments
This is the 180'th update of my fly longevity experiments. Average
temperature was 22.3 C during this run. Estimated maximal longevity using
the formula (363 - T*11.2) is 113 days.
A paper entitled "Cerium oxide nanoparticles extend cell longevity
and act as free radical scavengers" gave me an idea for testing the free
radical theory of aging. In the paper Beverly Rzigalinski detailed how
cerium oxide nanoparticles (2-10 nm) prevented rat brain cell cultures
from dieing in vitro. After 28 days control cultures were moribund, while
nanoparticle treated ones were still alive and well after 68 days. These
particles are believed to act as self-regenerating antioxidants, and also
act to protect against UV radiation.
Being a non-prescription item, I was able to purchase cerium oxide
nanoparticles from Nanophase Technologies Corporation. Product name is
NanoArc Cerium Oxide SGH, and product code #EXP0324. Price is $30 for 25
grams, with a minimum order of $300. Average particle size was 10 nm, so
these were somewhat larger than the average of 6 nm for the particles
used by Rzigalinski. I'm surprised that nanotechnology, albet just
unmachined nanoparticles was already available now, instead of in the dim
distant future. This is the first ever test pitting nanotechnology
explicitly against aging.
Cerium oxide nanoparticles turned out to be non-toxic to flies at all
concentrations. However no effect on fly longevity was observed. I have
to regard this as a refutation of the free radical theory of aging.
Playing the devil's advocate, this test of the free radical theory of
aging could be criticized along the following lines. The particle size
may have been too large so mitochondrial penetration may have been as
issue. Possibly too high a concentration of nanoparticles was used.
However with rather greater plausibility comes with the argument that
exposing rat brain cells to ambient oxygen amounts to exposing these
cells to a much higher level of free radicals than are encountered in
intact animals. Nanoparticles have not yet been demonstrated to lower
free radicals under normal in-vivo conditions.
Run #182 again tests nanoparticles, but at lower concentrations.
Run #180 Percent Survival on Day
supplement 6 15 22 30 39 47 57 65 71 78 86 94
__________________________________________________________
control one 100 87 70 50 47 47 40 23 13 3 0 -
control two 97 78 70 49 43 41 38 27 11 0 - -
cerium oxide 1/32 tsp 94 94 82 65 47 35 29 24 12 6 0 -
" 1/32 tsp 100 92 84 80 56 40 36 28 8 0 - -
" 1/16 tsp 100 82 73 61 52 36 27 24 18 6 0 -
" 1/16 tsp 100 97 94 74 58 48 39 29 23 7 3 0
" 1/8 tsp 100 89 79 61 43 39 29 21 21 0 - -
" 1/8 tsp 93 74 56 52 44 22 22 15 7 0 - -
" 1/4 tsp 96 82 70 56 48 37 26 22 7 4 0 -
" 1/4 tsp 100 92 79 71 63 38 38 33 8 4 0 -
" 1/2 tsp 100 82 74 63 56 48 30 26 11 4 0 -
" 1/2 tsp 87 63 60 53 43 43 37 30 7 0 - -
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