Leukemia in Hiroshima Atomic Bomb Survivors

The incidence of leukemia is higher among those closely exposed thanamong those more remote from the hypocenter. This increase was first manifestapproximately three years following exposure. It apparently reached its peakbetween the years 1950 and 1952. Thereafter, the incidence has been diminishing, but 13 years after exposure it is still higher than would be expected in thegeneral population. The type of leukemia most increased in incidence is thechronic granulocytic variety. No apparent difference in the natural history ofthe specific types of leukemia in exposed and nonexposed Japanese has beenobserved. Preliminary analyses of the data show a linear relation betweendose of radiation and incidence of leukemia above 50 to 100 rad. Below thisdose, the shape of the curve is not certain.

Submitted on June 8, 1959 Accepted on August 12, 1959     

The Relation of Blood Platelet Survival and Distribution to 14C-Serotonin Distribution and Excretion

1. The distribution of ¹⁴C-5-HT following infusion is different from that ofendogenous serotonin. One hour after infusion it is, in major part, a functionof the distribution of blood platelets.

2. The spleen in rats is the site of a pool of platelets. Based on both ¹⁴Cand platelet recovery data in normal and splenectomized animals, this poolapproximates 40 per cent of the total circulating platelets.

3. Postsplenectomy thrombocytosis may relate to removal of a platelet reservoir with shift of the platelets normally contained therein to the peripheralcirculation.

4. The shape of platelet survival curves in rats is neither strictly linear norcurvilinear but normally is determined primarily by age-related processes inthe platelet. Platelet survival curves tend to become curvilinear in thrombocytopenic animals, indicating that there is probably an additional small, fixedrandom loss of platelets from the circulation.

5. The disappearance of ¹⁴C-5-HT from blood platelets approximates but isnot completely representative of the disappearance of the platelets themselves.It is probable that elution from platelets and possibly reutilization of plateletlabel occurs.

Submitted on May 27, 1966 Accepted on September 21, 1966