Composite of dose-response data from 24 and 48 hours. Data from 24 and 48 hours as shown in Figs 2B and 3B were combined with an additional dose-response experiment in which Jurkat cultures were treated with 0, 90, 110, 120, 140, 160, 180, and 200 ng/mL of doxorubicin for 24 hours. The CH₂/CH₃ signal intensity ratio was plotted against the percentage of apoptotic cells as seen by nuclear morphologic analysis (r² = .947, N = 27 samples). The solid line is the best fit line determined by linear regression analysis; dashed lines mark the upper and lower limits of a 95% confidence interval plotted over the entire range of data.