et
yt ne eae.
A,myfas Bias,
Sdoo
37
The OR denoted the individual tissues, excretions, or physiological processes
involved in the preferential utilization of calcium over strontium, and when
less than 1, expresses such a preference.
rats on a canmercial diet was 0.27.
causing the discrimination.
For example, the Qbpone-diet for
The OR did not imply action by the tissue
Instead, to denote the phystological process of
discriminat fon in a given tissue, the authors utflized the term “StrontiumCalcium Discrimination Factor" (OF).
The product of the DFs equalled the OR.
That strontium was preferentially discriminated against by the placenta
|
I
was found in beagle dogs (AEC Project No. 6, 1958).
'
The ORfetal bone-diet
was 0,3], based upon data from two pups, a value somewhat Jower than the
ORadult bone-diet of 0.4-0.5 of mature beagles (Della Rosa et al., 1972).
The metabolic studies of radiostrontium intensified when its potential
toxicity as a conponent of radioactive fallout was recognized and studies on
its effects began.
The radiobiologfcal significance of strontium metabolism
was discussed in reviews (Thompson, 1960; Loutit, 1962; ICRP, 1972) and
symposia (Lenihan et a}., 1967; Goldman and Bustad, 1972).
Radiobjological Effects
The tumorigenic ability of radiostrontium was recognized jn the 1940s.
Strontium-89 was descrihed as a “producer par excellence of bone tumors” by
Brues et al. (1947), who reported that tumor development tn over 3000 mice was
approximately proportional to dose and to time, with a latent period that
itself was related inversely to dose.
Such a scheme was shown to fit data
that were available for human radtun dtfal painters.
Besides bone turors,
aplastic anenia and myeloid metaplasia were canmon at necropsy (Brues et al.,
1949),