Patients may have some additional blood tests done if they are among the first 10 patients taking part in this study. In this case they will have 9 samples of blood (each about a teaspoonful) drawn from them at specifically timed intervals (at 30 minutes before the start and at 30 minutes, 2 hour 55 minutes, 3 hour 10 minutes, 3 hour 30 minutes, 5 hour, 8 hour, 27 hour (+/- 1 hour) and 168 hour (+/- 4 hours) after the start of the ZK-Epo infusion) so that we can better understand the level of this drug in the body and its metabolism in people.