924 
GENETIC AND BIOLOGICAL EFFECTS OF RADIATION 
MITOTIC 
PRO 
NORMOBLASTS 
BASOPHILIC 
NORMOBLASTS 
BONE MARROW M ATU R AT I ON -ER YTH R 0 I D 
— I 1 — 
T — I I I 
T 1 1 1 — I I I 
I- 
1 
T 
T 
1 CONTROL (3) 
2 RUCF (9) 
3 CURN (10) 
4 RURN (8) 
5 CURE (7) 
6 RUF 
1 
(7) 
I 
J I I 
T 
T 
J I l_X. 
J L 
J I I I 
0.1 1.0 10.0 
PERCENT OF ERYTHROID CELLS 
Figure 3. — Pertinent Erythroid Marrow Maturation in Uterine-Milk Exposure Study (Mean ± S.E.), 
Hematoproliferative Disorders 
The spectrum of proliferative disorders ob- 
served in animals at the various dose levels is 
shovi^n in Table II. The histopathology of these 
dyscrasias has been previously described.^^ At 
the 3,100 /uCi/day level two of three animals de- 
veloped areas of myeloid metaplasia that were 
most evident in the liver, spleen, lymph nodes 
and kidneys, but with scattered foci in the my- 
ocardium and adrenals. 
The 625 )u.Ci/day offspring experienced an in- 
cidence of myeloid metaplasia of approximately 
50%. In addition, there was one case each of 
myeloid and lymphoid neoplasia. Most animals 
in this group died of an acute hemorrhagic syn- 
drome associated with profound thrombocyto- 
penia, leukopenia and anemia. 
At the 125 yu,Ci/day level, only 5 of 42 animals 
considered at risk developed myeloid metapla- 
sia. However, the incidence of hematopoietic 
neoplasia in the parents was approximately 
40% and in the offspring 70%, with the mean 
age at death being about 6 and 3 years, respec- 
tively. Of these, 61% were considered myeloid, 
28% lymphoid and 11% stem cell prolifera- 
tions. 
With lower accumulated radiation doses (1, 
5, and 25 yuCi/day), the incidence of metaplasia, 
and particularly neoplasia, was reduced and 
there was a greater tendency for production of 
lymphoid neoplasms. 
The hematopoietic neoplasms generally devel- 
oped relatively late in the particular lifespan 
for each dose level, and after accumulated ra- 
diation doses of 6,000 to 20,000 rads, the major- 
ity occurring at approximately 15,000 rads. 
Clinically, these neoplasms were characterized 
by being very acute in nature with only a few 
weeks between the presence of blast forms in 
the peripheral blood and death of the animal. 
About one-half of the myelogenous leukemia 
cases had leukemic peripheral blood values. The 
majority of the myelogenous leukemias were 
classified as granulocytic, with one each of eosin- 
ophilic, basophilic, DiGuglielmo's disease, and 
two myelomonocytic forms. 
