4.0
Iaeroduction
Fua.owine trae Deros anon of a nuclear devive
at the Pacific Proving Ground in the Spring of
1954, 28 Americans and 238 Marshalle-e were
eovpramd to fallout rediations, Sixty-four of
the Marshallese on Rongelap atoll ((iroup 1)
received an estimated 1/5 r. of gamma radiation
as measured in air; 1% Marshallese on Ailinginae atoll (Crroup IL) received 69 r.: 28 Ameri-
cans on Rongerik atoll (Group TET) received 1
r.; and 157 Marshallese on Utirik atoll (Group
IV) received {4 7. Detailed history of the
event, as well as clinical and internal contamination findings are reported respectively in Chapters I, If and V. This chapter presents the
hematological findings in the exposed individuals during the first 11 weeks, at 6 months, and
at 12 months after exposure.
Since it is generally agreed that the degree
of change in the formed elements of the blood
is the most useful clinical index of the severity
of radiation damage, peripheral blood changes
were relied upon as a major aid in evaluating
the degree of radiation injury in each exposed
individual. In addition, changes in the mean
blood counts of the exposed groups were followed closely to aid in evaluating the changing
status and probable prognosis of the exposed
yroups. Therefore, emphasis was placed on
standardized systematic serial determinations
in order that individual and group trends could
be evaluated adequately. Since it was necesvary to observe the large number of exposed
individuals at frequent intervals, the number
of different procedures that could be done was
necessarily limited. Determinations employed
were chosen on the basis of known clinical value,
and euse and rapidity with which they could be
done reliably under Held laboratory conditions.
Accordingly coagulation and biochemical
studies were omitted.
An extensive literature exists on the hematologic effects of radiation. These data, and the
difficulties attendant on comparing them with
the present result. are discumed later in this
report.
4.1
Methods
Hewotoogtcw Examisinose [sccceep total
leukocyte, neutrophile, Ivmphocyte and plate-
let counts, and hematocrit determinations.
Whenever pomible, an entire exposure group
was studied in a single day with 2 days occasionally required to complete the larger
groups.
Capillary blood, usually obtained from the
finger and rarely fromthe heel or ear was used.
Two pipettes were tilled for both the leukocyte
and platelet counts. From each pipette a
single hemocytometer chamber was filled. All
pipettes were rotated for 10 minutes, and the
cells were allowed to settle for 10 minutes in the
hemocytometer chamber before counting. A 3
percent acetic acid diluting fluid was used for
total leukocyte counts.
The blood was diluted
with 1 percent ammonium oxalate for platelet
counts and counted in fat bottom hemocytom
eters using a dark phase contrast microscope
(1). Two blood smears were made using a
beveled end glass slide for spreading. One
blood smear was fixed in methyl alcohol, The
other was stained by Wright's method, from
Which a Loo cell differential count was made.
Hematocrit. were performed using heparinized
capillary tubes. One end of the capillary tube
was heat sented and the tube wes centrifuged in
aocapilary centrifuge at
12500 rpm for 5
moniites,
Every effort was made to maintain uniform
procedures in every phase of the Jaboratory
work. The number of personnel changes for a
given procedure was held to a minimum: personnel drawing blood from a single puncture
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