Qa
fee
imals within 30 days), recovery in the
f
Q
(that dose which kills 50 per cent of th
raboit takes about 50 days from the tine of the exposure.
Sth days after exposure, there is
ezeese in nunber.
Between the 3rd and the
a temporary tendency for the Lymphocytes to ine
This is follewsd by a deezcase to almost the maximum depression
that wes present 24 to 72 hours after es:yosure (fig. 2).
This type of recovery
followed by a wave of destruction, is, in general, characteristic of all blood
celis and tissues (Jacobson et al,, Dicom).
Similar changes were observed in swine
exposed to 1000 kvp x-ray in various docozes, and in dovs after 2000 kvp x-ray
(Cronkite et al.).
8.6.2
Gronulocytes.
In vitro studies on gscnulocytes have demonstrated that
both the normal granulocytes and nyclozenous leukemic celis ere resistant to x-ray
after doses of 1000 r (Schrek).
Changes in the numbers of granulocytes in the peripheral blood follow a differ
ent course (fig. 3).
In generci, all animals respond with a period of granulocy=
tosis predominately neutsophitic om hetesophitic (rabbits) during the first 24 to
48 hours after essposure to
amounts of rcadiavica in the subd-Aethal and Iicthal range.
This granulocytosis appears as two peaks in the rabbit at about 12 ond 18 hours
after exposure.
The second peak may be cue to accelerated Liberation of ceils froa
the tone marre.;..
The granulocytosis usuciiy doses
ot Last for more than 24 hours
"
out the body.
The first peak may repzesent mobilisatien of granulocytes through-
but may last lonser in some species and under certain conditions.
A definite granu-
locytosis, however, appears du ing the first 24 hours in the dog but the biphasic
response of the rabbit was not observed.
Generally, the manisum depression of the
gronulocytes is cttained by 72 to 96 kourss afters exposure.
Recovery of the granulo-
cyte Levels besins by 10 to 15 days after exposure, or sooner with smeil doses.
In
genesal, if cronulocyte icvels co not inczease or semain constant, even though at a
low level, by the ASth day, death
usucltly
ensues (Czenkitc}).
As a cule, there are
one or more abortive rises in the granulocytes that appear between the third ond
l2th days after exposure, depending oa the animal species and the dose of radiation.