incorporate into a tube structure formed by human umbilical vein endothelial cells huvecs 250 u03bcl matrigel was coated on a 24 well plate and kept at 37 u00b0 c for 30 minutes in order to track bm spheroids incorporating into a tube structure formed by huvecs bone marrow derived from gfp was used and huvecs were cultured on the matrigel together with fresh bm mncs bm spheroids bm non spheroids and bm dissociated spheroids dissociated into individual cells further indirect effects of co culture were examined in order to isolate the huvecs cultured on the matrigel the fresh bm mncs the bm spheroids and the bm non spheroids were placed on a culture membrane insert well and co cultured the cells were cultured in ebm 2 added with 1 fbs after 24 hours tube structures formed by the huvecs cultured together with the respective cells were compared and cells of the tube structures were labelled with 25 u03bcg ml calcein am and the tubes labelled with a fluorescent dye were observed under a fluorescence microscope an in vivo matrigel plug assay was carried out to observe blood vessels newly generated in a gel plug transplanted together with cells under the skin of a mouse in order to evaluate the degree of contribution of cells transplanted in vivo to angiogenesis 1 u00d7 10 6 gfp bm spheroids bm non spheroids or fresh bm mncs were used and the.