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Clinical hematopoietic stem/progenitor cell (HSPC) transplantation outcomes are strongly correlated with the number of cells infused. Hence, to generate sufficient HSPCs for transplantation, the best culture parameters for expansion are critical. It is generally assumed that the defined oxygen (O2) set for the incubator reflects the pericellular O2 to which cells are being exposed. Studies have shown that low O2 tension maintains an undifferentiated state, but the expansion rate may be constrained because of limited diffusion in a static culture system. A combination of low ambient O2 and dynamic culture conditions has been developed to increase the reconstituting capacity of human HSPCs. In this unit, the protocols for serum‐free expansion of HSPCs at 5% and 20% O2 in static and dynamic nutrient flow mode are described. Finally, the impact of O2 tension on HSPC expansion in vitro by flow cytometry and colony forming assays and in vivo through engraftment using a murine model is assessed

Oxygen levels are an important variable during the in vitro culture of stem cells. There has been increasing interest in the use of low oxygen to maximize proliferation and, in some cases, effect differentiation of stem cell populations. It is generally assumed that the defined pO2 in the incubator reflects the pO2 to which the stem cells are being exposed. However, we demonstrate that the pO2 experienced by cells in static culture can change dramatically during the course of culture as cell numbers increase and as the oxygen utilization by cells exceeds the diffusion of oxygen through the media. Dynamic culture (whereby the cell culture plate is in constant motion) largely eliminates this effect, and a combination of low ambient oxygen and dynamic culture results in a fourfold increase in reconstituting capacity of human hematopoietic stem cells compared with those cultured in static culture at ambient oxygen tension. Cells cultured dynamically at 5% oxygen exhibited the best expansion: 30-fold increase by flow cytometry, 120-fold increase by colony assay, and 11% of human CD45 engraftment in the bone marrow of NOD/SCID mice. To our knowledge, this is the first study to compare individual and combined effects of oxygen and static or dynamic culture on hematopoietic ex vivo expansion. Understanding and controlling the effective oxygen tension experienced by cells may be important in clinical stem cell expansion systems, and these results may have relevance to the interpretation of low oxygen culture studies.

Oxygen levels are an important variable during the in vitro culture of stem cells. There has been increasing interest in the use of low oxygen to maximize proliferation and, in some cases, effect differentiation of stem cell populations. It is generally assumed that the defined pO2 in the incubator reflects the pO2 to which the stem cells are being exposed. However, we demonstrate that the pO2 experienced by cells in static culture can change dramatically during the course of culture as cell numbers increase and as the oxygen utilization by cells exceeds the diffusion of oxygen through the media. Dynamic culture (whereby the cell culture plate is in constant motion) largely eliminates this effect, and a combination of low ambient oxygen and dynamic culture results in a fourfold increase in reconstituting capacity of human hematopoietic stem cells compared with those cultured in static culture at ambient oxygen tension. Cells cultured dynamically at 5% oxygen exhibited the best expansion: 30-fold increase by flow cytometry, 120-fold increase by colony assay, and 11% of human CD45 engraftment in the bone marrow of NOD/SCID mice. To our knowledge, this is the first study to compare individual and combined effects of oxygen and static or dynamic culture on hematopoietic ex vivo expansion. Understanding and controlling the effective oxygen tension experienced by cells may be important in clinical stem cell expansion systems, and these results may have relevance to the interpretation of low oxygen culture studies.

1, State comprehensive universities (SCUs) feature degree programs designed to help graduates achieve their career aspirations. Criminology and Criminal Justice (C&CJ) programs have become popular at SCUs, in part because students are inspired by media portrayals of law enforcement to work in the criminal justice field. Yet little is known about how C&CJ alumni of SCUs perceive their educational experiences. For this exploratory study, an online survey was distributed to alumni of a Southern SCU C&CJ program. Alumni were asked about their perceptions of their own career preparedness following graduation and their satisfaction with the C&CJ program. Overall, alumni were satisfied with their education and felt prepared for the workforce. Students raised in the same region as the location of the SCU felt particularly ready to establish a career upon graduation. The findings have important implications for future research in the area of career preparedness among SCU graduates and C&CJ majors specifically.

1, State comprehensive universities (SCUs) feature degree programs designed to help graduates achieve their career aspirations. Criminology and Criminal Justice (C&CJ) programs have become popular at SCUs, in part because students are inspired by media portrayals of law enforcement to work in the criminal justice field. Yet little is known about how C&CJ alumni of SCUs perceive their educational experiences. For this exploratory study, an online survey was distributed to alumni of a Southern SCU C&CJ program. Alumni were asked about their perceptions of their own career preparedness following graduation and their satisfaction with the C&CJ program. Overall, alumni were satisfied with their education and felt prepared for the workforce. Students raised in the same region as the location of the SCU felt particularly ready to establish a career upon graduation. The findings have important implications for future research in the area of career preparedness among SCU graduates and C&CJ majors specifically.