Light microscopy reveals karyorrhectic morphology after PDA-66 treatment in SEM and Jurkat cells. Cytospins of SEM and Jurkat cells were stained with Pappenheim method after 48 h incubation with 1 μM PDA-66 and DMSO, respectively. Representative pictures are displayed. The upper pictures show SEM and Jurkat cells after DMSO treatment, the lower ones show PDA-66 treated cells. After treatment with PDA-66 an increased amount of cells with chromatin condensation (black arrow a) and karyorrhexis (black arrow b) could be observed along with more cell debris.