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Recently Benditt has shown 640) that the human atheroselcrotic plaque is
a monoclonal proliferation of a mutated cell of the artery wall, and thus
, an arterial tumor.
Elkeles
(41-43)
nas observed anonzlously high concen-
trations of alpha activity at the calcified piaque sites.
In additicn
atherosclerosis plaques normally occtr in the cain and aicominal aortas:
oe
"
and the coronary arteries, but rarely in the pulmonary arteries
(42-44)
.
This distribution suggests a respiratory origin for the mutagenic agent.
Attempts to reproduce arterial lesions in animals by chemical, mechanical
and nutritional means have not produced plaques sinilar- to those of
atherosclerosis in man (40) .
However atherosclerotic plaques have been
directly induced in human arteries by intensive irradiation with \-rays
. (45) and radium
’
There is a high incidence
of early coronaries among
cigarette smokers, with a mortality rate for males who smoke two packs or
more daily that is 2 to 2.5 times that of non-smokers but at a mean age
of death some 10 to 16 years earlier ("oy ail. these reasons it is proposed
that inhaled insoluble alpha emitting smoke particles are very likely to be
.-
the mutagenic agent which gives rise to atherosclerosis in cigarette smokers,
If this is the case, similar increased risk of early coronaries are to be
expected for other groups of individuals who are occupationally or environmentally exposed to the dnhalation of insoluble alpha emitting particles
of respirable size.
Attention should be addressed to industrial and combustion
product aerosols:which contain uraniun oxide, thorium oxide and lead-210,
as well as to plutonium oxide from nuclear industry, nuclear accidents
and fallout from atmospheric nuclear tests,
The first and most obvious place to look for such effects iS
Past and present plutonium workers,
among
Very significant increases in the
incidence of carly coronaries as well as lung cancers and cancers at other
sites is observed among ciparette smokers
(46)
aa
iy il
.
we
7 ere
with insoluble alpha emitting
.
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feces