ACUTE RADIATION EFFECTS ON MAN
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(Thomaset al., 1959). This leaves us with an unsatisfactory therapeutic
vacuum between the highest dose level at which replacement therapy is
effective and the lowest exposure that depresses the immune response
sufficiently to allow a homologous graft to take. A similar gap may
perhaps exist in man.
It is difficult to estimate the dose range in humanbeings wherefunctional
replacement therapy would be necessary and helpful. The inhabitants of
the Marshall Islands who received about 175 r did not require therapy.
Somevictims of the Oak Ridge accident received brief treatment with antibiotics (Brucer, 1959) and some of them were close to needing platelet
transfusions. In general, replacement therapy will be needed for exposures
above the level of the minimallethal dose, which is probably in the vicinity
of 250r. Obviously, the frequency with which this treatmentwill be needed
will increase with the dose. The upperlimit of exposure at which this therapy
will be successful in man is not known. The Yugoslav accident (Jammetet al.,
1959; Mathé et al., 1959) might have shed somelight on this question, but
since bone marrowtransplants were also administered interpretation of the
regeneration and survival data is difficult.
Establishment of this upper
limit is particularly important since it would also delineate when an attempt
at bone marrowtransplantation would be justified. Homologous bone
marrow transplantation in man may not be an innocuous procedure and
should be employed only after serious consideration. At the present time
attempts to transplant homologous bone marrowarejustified, we believe, in
the presence of severe pancytopenia and when chances that replacement
therapy alone would be sufficient are small. This would probably mean
patients who had survived the gastrointestinal syndrome, who had vomited
severely for more than 48 hours after exposure, who at 24 hours hadless
than 500 lymphocytes per mm*, or who had a rapidly declining white cell
count.
Frequent bone marrow aspirations may be helpful in making this
range.
This programme can be summarized asfollows:
difficult decision. It may be worth emphasizing again that bone marrow
transplantation is not the only treatment available in acute radiation injury.
If it is permissible to extrapolate to man the findings in dogs reviewed above,
it may be expected that a conservative therapeutic replacement programme
would be life-saving in many cases, particularly in the lower lethal dose
1. Large doses of antibiotics when signs of infection are present; the
choice of antibiotics should preferably be based on repeated cultures and
sensitivity tests.
2. In case of haemorrhage or immediate danger of bleeding, transfusions
of fresh blood or platelet-rich plasma (within four hours after collection,
preferably less), using siliconized equipment and plastic bags.
3. Protection of the patient against exogenous stresses, particularly
infection.