On Monday Neupogen plus HBO2 will be repeated and on Tuesday morning a blood sample will be obtained. This is for counting stem cells to asses if an adequate number is mobilized (hence an aspect of normal clinical care) and also an extra 4 ml tube of blood will be obtained for the additional studies of HIF in stem cells to be done in the PI's lab. If the cell count exceeds 20/ml blood the subject will undergo apheresis to harvest stem cells on that day. If the cell count is less than 20/ml, the subject will again receive a Neupogen injection and HBO2 and an additional drug that is part of normal care called plerixafor. On Wednesday morning a blood sample will again be obtained to asses if an adequate stem cell number is mobilized (hence an aspect of normal clinical care) and also an extra 4 ml tube of blood will be obtained for additional studies to be done in the PI's lab. If the cell count exceeds 20/ml blood the subject will undergo apheresis to harvest stem cells on that day. If the cell count is still less than 20/ml blood, the subject will again receive a Neupogen injection and HBO2 and an additional dose of plerixafor. It is anticipated that by Thursday morning, when another blood cell count will be done, the study subject will be able to proceed with harvesting their stem cells by the apheresis procedure.