Effects of Negative Pi Mesons on Mouse Bone Marrow Cells

Abstract
Mouse bone marrow cells exposed in vitro to graded doses of negative pi mesons at 3.5-6.0 rads/min gave Do [median lethal dose] values of 180 rads in the plateau (0.6 and 12.0 cm), and 130 rads in the peak (16.5 and 18.4 cm). Survival curve shoulders were narrow, with Dq [quasi-threshold dose] values of 25 and 15 rads for plateau and peak positions. .gamma.-rays from 60Co at 4.5 rads/min, produced a curve with wider shoulder but steeper slope such that the RBE [relative biological effectiveness] was essentially 1 for single doses between 100-400 rads.