"The biological action of roentsen rays is greater the higher the reproductive ace
tivity of the cell, the ldonses the period of its mitosis, and the less the degree
of differantiation of the
cell in respect to its morphology and function."
Recovery of the stem cclis, thois reproductive sate, tha rcicase fron the
pheral
elements.
dotermine the
Lo
marrow ond the cate of destruction
reappearance rate of the peri-
it may take many months for the nuuber of cells in the peripheral
blood to return to poeedizradiation levels (fics. 2 and 3).
Why the peripheral
level of leutocytes is semetines set ato a Lewes level for a icng period is not
Known.
Perhaps the release mechanism is altered.
In this respect, Brecher et al.
have shown that the level of blood ccolis in the pesipherad bicod of the mouse re
covering from radiation injury is not a geod inde: of the activity of the henatopoictic organs.
For
exanpic, there may be emstremoaly active kenatopoicsis with per=-
sistent low levels of leukocytes in the peripheral blood.
Residual injury of the
formative cells may be manifested by the late copearance of blood dyscrasias.
Similar delay in recovery was seen in the Marshalicse (sce section 8.6.5).
8.6
Variations in Number and Mospholozy of Diced Cells.
Specific chanres in the morpholesy and nuxber of
blood have been extensively studied.
coils in the periphol
Pasticular attention has teen paid to the
relationship of doscce to the magnitude and cate of changes in the blood.
chances that take place after a single exposure to
Sidered first.
The
ionizing radiation will be con-
Jacobson and associates have studied extensively the effect of
single doses of different magnitude upoa the bicod of rabbits.
Ali manmais scem
to follow the same general pattern, except for some differcneos in the rate of
Lonoy has desecibed the hematologic changes tact were observed in the Japanese caosucities at Hicoshima and Nasacati.
These
chonses will not be discussed in