The 50,000 and also the 100,000 cell dosages are meant for the safety evaluation and not so much for the efficacy. I understand, even 50,000 cell dosage must show some effect; but, keeping in view nearly blind patients, perhaps it needs a longer period and additional such injections to show significant improvement. The six-month period for the trial for each thus may not be enough to judge efficacy for 50,000 or even 100,000 cell dosages. The fact remains that after the two stages, there is absolutely no side effect (unlike OPC1!) and had an indication that there is some positive effect on the patients' vision. Of course more will be known soon since the second cohorts for both SMD and AMD are now done and they are moving to the third stage. However, we must be mindful that where the injected cells in the ACTC's trials affect only the retinal portion of the eye, injected cells in Geron's OPC1 trials affected almost the entire blood stream in the body. Thus, to answer Black's original post's comment regarding comparision of the cell quantities for the two, it is improper.