Limiting dilution analysis of LTRC marrow concentration with frequency estimated as the negative inverse of the least squares derived slope.

For NBr marrow the results of assays performed at 6, 12, and 20 weeks were pooled and plotted as a single point (♦, solid line); frequency was 1 LTRC/502 000 ± 70 800 (± SE) marrow cells withr² = 0.91 and y-intercept of 0.91 (0.79 − 1.05 ± SE range). AKR/J marrow (▪, dotted line), 1/ 47 700 ± 4600, r² = 0.96, y-intercept of 0.98 (0.89-1.08). C3H/HeN mice (○, line not shown); 1/41 800 ± 8700, r² = 0.85, y-intercept of 0.71 (0.56-0.90). Numbers of rats per point are in parentheses. For mice, depending on survival, 6 to 12 mice were used per point.