Stimulation of the side population fraction of ATDC5 chondroprogenitors by hypoxia.

The influence of oxygen tension on the side population (SP) fraction sorted from ATDC5 chondroprogenitor cells was investigated. ATDC5 cells cultured in normoxia (20%) or hypoxia (1% oxygen) were compared. The SP fraction was significantly higher in the cells cultured in hypoxia.

Nine-color flow cytometry for accurate measurement of T cell subsets and cytokine responses. Part I: Panel design by an empiric approach.

Polychromatic flow cytometry offers the unprecedented ability to investigate multiple antigens per cell. Unfortunately, unwanted spectral overlaps and compensation problems increase when more than four colors are used, but these problems can be minimized if staining combinations are chosen carefully. We used an empiric approach to design, test and identify six-color T cell immunophenotyping reagent panels that can be expanded to include three or more functional or other markers in the FITC, PE, and APC channels without significant spectral limitations.

Identification of superficial zone articular chondrocyte stem/progenitor cells.

Identification of progenitor/stem cell populations that differentiate specifically towards superficial zone articular chondrocytes is an unmet challenge for cartilage tissue engineering. Using fluorescence activated cell sorting (FACS) analysis we found a characteristic pattern of "side population" (SP) stem cells identified by the Hoechst 33342 dye. We established micromass cultures from this population of cells and tested their chondrogeneic potential.

Soluble factors elaborated by human brain endothelial cells induce the concomitant expansion of purified human BM CD34+CD38- cells and SCID-repopulating cells.

The CD34(+)CD38- phenotype identifies a population in the bone marrow that is enriched in the steady state for hematopoietic stem cells (HSCs). Following ex vivo culture of CD34(+) cells, HSC content is difficult to measure since committed CD34(+)CD38+ progenitors down-regulate CD38 surface expression during culture. In this study, we sought to define the phenotype of human HSCs following ex vivo culture under conditions that support the expansion of human cells capable of repopulating non-obese diabetic/severe combined immunodeficiency (SCID)-repopulating cells (SRCs).

Quantitative analysis demonstrates expansion of SCID-repopulating cells and increased engraftment capacity in human cord blood following ex vivo culture with human brain endothelial cells.

Initial clinical trials examining the transplantation of ex vivo expanded cord blood (CB) cells have failed to demonstrate an impact on hematopoietic recovery compared with historical unmanipulated CB controls. In this study, we tested whether coculture with primary human brain endothelial cells (HUBECs) could increase the engraftment capacity and repopulating cell frequency within CB CD34+ cells. Quantitative analysis demonstrated that HUBEC coculture for 7 days supported a 19-fold greater number of CD34+ cells and 3.