one individual, considered as a typical response
im a non-fatal Japaneses (13) indicated an apperent lew approximately on day 90. This time
trend agress with thet seen in the Marshallese
end Americans expesed to falleut radiation.
Ft ia worthy of note that the period of peak
incidence of perpera in the Japanese victime
occurred betweee the 25th and 30th day, which
cerresponds to the time of maximum platelet
depression in the exposed Marshallese.
443 Comperissa With Decs From Laborsenry
Accidene
Although in the Los Alamos (18) and Ar-
gonne accidents (19) the type of radiation
and the conditions of exposure were markedly
different from either the Japanese oc the Group
I situations, a large component of penetrating
gamma and neutron radiation was received and
thus attempts at comparison may be of value.
Some findings in the hematological responses
are pointed out: a) a uniform early rise in
wiite and neutrophile counts over the first few
dava, similar to that seen early in the American
group was obeerved uniformly.® b) of three
The Argeane Laborstory accident (19) involved feur individuals whe were catimated to
have received 138, 127, 60 and 9 rep, rveper-
tively. The findings in the two highest exposed
individuals in general were consistent with
those in the present study. An initial neutre-
_ philic leukorytesis was follewed by fluctuations
in total count, with low valuce continuing inte
the 7th week. Recovery was not complete by
the 20th week. The lymphocyte depression was
rapid and marked, recovery was not evident by
the 20th week. Minimum values for the platelet counts were obtained between the 25th and
3ist day.
Comparison with Animal Data. The time
trends and severity of peripheral blood count
change following total body radiation in ani-
mais has been examined critically recently (15),
and the following general conclusions are
presented.
a) An initial rise in total white count (reflected in the neutrophile count) may occur.
Thereafter the magnitude of depression of the
total white and neutrophile counts, and within
limits their duration are a function of radia-
tion dose. .\ secondary or abortive rise in the
total white count (reflected in the neutrophile
or lymphocyte count) may occur, followed by a
high-exposure but non-lethal cases, the total
white and leukocyte counts continued to show
second decrease. There is little species difference in the rate of depression of the total white
heyond.
ever, the rate of recovery and time for complete
recovery is quite different in various species.
some deyree of depression into the 7th week or
c) the lymphocyte counts in individ-
uals expowed to as little as 30 rem showed an
initial marked depression.
In most cases the
lymphocyte counts remained at low tevels
throughout the period of vbeervation. d) platelet counts were done by a different method, and
absolute counts are therefore not comparable.
However, of the three high dose survivors,
times of maxim depression were not incon-
sistent with the value of 50 days obtained in the
prevent studies,
In higher dose non-survivors,
however, the platelet counts had reached mini-
mum Values ax early ax the sth day.
°Ne cummin were taken om tora | and [1 during
the fret TS hours.
or neutrophile count at comparable doses; how-
Stall animals (mouse, rat, hamster) show rela-
tively complete recovery to control levels, even
at doses in the lethal range, by the end of the
oth week or earlier. Data on dogs are inadequate to indicate when recovery is complete;
however, return to control levels at high dose
levels has not occurred by the ith week. Swine
require 9 to 15 or more weeks for complete
recovery.
b) The response of lymphocytes is essentially
identical in all animal species. Depression can
be detected within a few hours, and recovery
from the minimum values (achieved in 36 to 48
hours) requires longer then does neutrophils
recovery. Lymphorvtes fall to very low levels
ee ee ee gee ee
peared ts show a mere consistent pettern than
did the louhery!.. counts. Platelet counts cox