age
8.3.1
Direct and Abscopal Effects.
The problem of direct versus indirect
(abscopal) injury of tha hematopoietic organs has interested many workers and as
yet has not beca satisfactorily answered.
Kornblum, Hoermer and Henderson state
that postial body radiation, as in therapy, has both a direct and an indiscet
effect upon the peripheral bicod and organs of hematopoiesis.
The indirect effect
upon non-irrcdiated parts is presumably mediated through circulating toxic pro-
Cucts.
Similar indirect effects have been alluded to by many other workers.
Osgood, by virtue of a bone marrow cultuse technique, concluded that there were
no indizsect effects.
Barnes and Furth, using parabiotic animals, concluded that
there was a slight but definite indiscct effect on the none-irradiated rat of the
parabiotic pairs.
Lawrence end associates, in a complete analysis of the probien,
reviewed the existing literatuze and presented evidence, based on cross-circulationa
experinents, that led then to believe that there is no good evidence for the presence of circulating toxins that sicnificantiy affect the peripheral blood.
It is
the opinion of these writers that the subject is not settled but the weicsht of the
evidence todsy strongly suggests that there is no circulating "Leukotozin"™ that acts
in a destructive mannes on the blood and organs of hematopoiesis or other tissues.
The use of the term “indirect” by biologists has been questioned by Mole since
chemists have
pziority on its use in a manner distinctly different from the way in
which it hes been used by bioloszists.
Chemists use it to describe the effects of
radiation mediated by the products of isradiation of water (the chemical effects of
free cadiccais, peronides, e¢c.}.
Accordinsly, Mole hss coincd the tern “abscopal"
to desezibe effects tozing place renotcly from the site of irradiation.
lem of cbscopal effects has been investigated by Raventos and Lond et al.
The probThe
latter srcup concluded that abscopcl effects, such as spleen, thymus and adrenal
weight chanses, develop only if and when the irradiation given imposed a severe
stress on the animal as indicated by gross iiiness.
Under such conditioas, chonges
in spleen, thymus ond adrenal weights are characteristic of the stress syndzoze.
mos \ 4 5 7
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