Six healthy adult individuals (18-65 yrs), with no current, ongoing infection or chronic disease will be recruited for this study. Treatment study subjects will undergo a daily exposure to 2.0 ATA, 100% Oxygen for 90 minutes over 5 days.

Two healthy study subjects with no current, ongoing infection or chronic disease will be rectuited to serve as a baseline group. Study subjects will not be exposed to HBO, but will have blood drawn at the same time as the treatment group.

Hyperabric oxygen will be delivered via a PerryPerry-Sigma Monoplace Hyperbaric Chambers. Oxygen is supplied by Air Gas, Seattle.

All gases will meet Health Standards for oxygen and air. The hyperbaric chamber technicians employed by Restorix Health are trained health personnel who will be assisting our study participant and monitoring the HBO treatment. Oxygen will be delivered at a pressure of 2.0 ATA for 90 minutes, once a day for 5 consective days.

Six treatment subjects and two control subjects will have two daily blood draws. Exposures of hyperabric oxygen (HBO) will occur daily over 5 consecutive days. The blood draws will occur prior to starting HBO exposure and after finishing with the HBO exposure. Control subjects will have their blood drawn at the same time as the treatment subjects, in ordert to establish a non-treatment baseline. The stem cell population that is resident in the peripheral blood will be analyzed using the cell sorting and cell identification system at Aldagen. Mononulcear cells will be gated on the basis of forward and side laser light scatter, and 250,000 events will be analyzed to determine the percentage of ALDHbr cells, and the expression of additional stem cell markers, such as CD45, CD34, and CD105.