2,
After a single doue of radiation to the body as ac whole there=
fore, the changes in the circulsting bloo. at any one time after
xposure, depend to a large extent upon the length of life or
rete or turnover of circulating Cel). 3« 'i, cen Look on the cir=
£ species cach with its
culeting celis as r@pulctiongs compe .2
3 eto is redueed to zero or
own averege 1ife span. if the birth r
ely wiaffected,
Lab
near aero by rediztion oni the adults reriin relativ
au
ting blood cells will bs proportional
depopulation of the circula
.
a»
tort’ iste span of each cpccies of celh. Thus, marked reduction
in the popul:tion of short-lived celis will, become apvarent before
marked reduction of the long-lived colic.
There is tason to believe that the averse lite span of the
white blood cells is a mutter of a few hours, that of the blood
platelets is a matter of a few days, anu that of the red biood
cell cs matter of more than 1CO days. «fter « single dose of
radiation, the theoretic-lly anticipatec order of disappearance
of circulnting celle would be first the white cells, second the
platelets, end third the red blood cells. Indiaed, the red blood
cell population might be expected to become/readuced so slowly
certain desares of radiation that regeneration {active
after
nm shen “Cf celis):mie©
occur before the reduction in numbers
had attained a magnitude reacily detectesle by currgnt leboratory
mothoces The fundamental demaze to perent red cell
types in
c
36
the bleod pis
the redleser
cent profoundly
eq
because of the longetivity
"4
such 2 case could be asid te be mchcd
ef the circulating red blood geld.
Ife
d
G
foreCiabion, ts affacted by
ioue perent celis.
A given dese
ane Gil¥ slightly damage another.
The abjlity of tissuss to rogererabe is ens ef grsat inpertance,
of demage will be mere readily effocted ty
c.pacitics for regeneration.
host worthrhile obcervations on effect cf
in smfimels.
Detai
f-
4.
wo
Repeir
single dcseshf radiation heve
ed data on the effects of ve:ying desage of wadiaticn on
asét3 will be presented inthe body cf the lecture.
required to preduce
tigeucs vith marked
The aiact amount of rediation
+
a civen effect on a given cell varies with different species, but
the following cbservations seem reasonably wll establishode
2,
The lymphocyte-(a type of white blood celi.) producing tissves
are the most sunsitive to radiadfon danage, The tissre pro-
ducing platelsts, red blood cells, and gronulecytzs ( the latter
is unother typo of -hite blood cell) sre less sensitive and have
a sensitivity boughly comparable one toths octner. Here is some evidence
the rea blood cell-forming tissues may be imdermediate in sensitivity
between the lymphocyte anc other bicod cells-emors sensitive than the
latter,
Zo
less sc than the former.
As was expected on the basis of l:novwledge of the life span of
-