H. A. RAGAN, P. L. HACKETT, B. J. MCCLANAHAN AND W. J. CLARKE 
925 
MITOTIC 
MYELO- 
BLASTS 
PRO- ) 
MYELOCYTES J 
0.1 
BONE MARROW M ATU R AT I ON -M YELO I D 
1 1 1 — I — I — r-r 
I I 
T — I — r 
=1 1 
1 
CONTROL 
(3) 
2 
RUCF 
(Q) 
3 
CURN 
(10 
4 
RURN 
(8) 
5 
CURF 
(7) 
6 
RUFj 
(7) 
1 
J L 
J I L 
1.0 
10.0 
PERCENT OF MYELOID CELLS 
Figure 4. — Pertinent Myeloid Marrow Maturation in Uterine-Milk Exposure Study (Mean ± S.E.). 
There were two cases of myelogenous leuke- 
mia observed in 62 control animals at risk. 
Curiously, both of these animals developed 
eosinophilic forms. There have been no cases of 
lymphoma observed in our control population. 
DISCUSSION 
Although significant postnatal radiation ef- 
fects of ^°Sr have been manifested at several 
high dose levels, there was no evidence of in- 
creased fetal or neonatal mortality even at accu- 
mulated fetal radiation doses of greater than 
150 rads. Since the fetus receives little radia- 
tion from maternal tissues, and ^<'Sr is a bone- 
seeking radionuclide, the sensitive fetal tissue 
would be well differentiated prior to the time a 
significant ^°Sr concentration would begin ac- 
cumulating. This does not, however, presume 
that bremstrahlung radiation from maternal 
Table II. — Hematoproliferative Dyscrasias in Swine Ingesting ""Sr 
»°Sr Level 
(^Ci/day) 
Generation 
Number of 
animals 
at risk 
Age at 
death 
( months ) * 
Average 
rad dose 
(x Iff") to 
skeleton* 
Lymphoid 
neoplasms 
Myeloid 
neoplasms 
Stem cell 
neoplasms 
Myeloid 
metaplasia 
3100 
Parent 
3 
12-13 
7-10 
2 
625 
Parent 
6 
17-19 
6-9 
2 
Fi** 
28 
3-34 
2-10 
1 
1 
15 
125 
Parent 
10 
66-88 
13-17 
1 
3 
3 
Fi, Fa 
32 
24-57 
10-20 
7 
14 
3 
2 
25 
Parent 
12 
54-123 
2-6 
2 
Fi, Fa 
32 
50-93 
3-6 
2 
1 
5 
6 
Parent 
0 
Fj, Fs 
24 
82 
1.0 
1 
1 
Parent 
17 
92-96 
<0.04 
1 
1 
I'l, F2 
59 
52-81 
<0.2 
4 
1 
0 
62 
103-105 
2 
1 
♦ For those animals with hemoproliferative disorders. 
** Removed from ""Sr feeding at 3 months of age. 
