Characterization of 2-phase liquid culture of erythroid cells. (A) NO production during erythroid differentiation (per 1 × 106 cells; n = 3). (B) Total globins per total protein levels during erythroid differentiation of CD34+ cells. The heme group of globins gives a maximum absorbance at 415 nm, while 280 nm is the maximum absorbance for most proteins (because of tryptophan, tyrosine, and phenylalanine; n = 3). HPLC analyses of HbA and HbF during erythroid differentiation (n = 4). (C) Detection of extracellular NO levels with fluorescent indicator DAF-2 in erythroid progenitor cells at day 6, during treatment with bradykinin (n = 3). Values are means (± SEM). *P < .05 and **P < .01 compared with cells at day 4 (B) and untreated with bradykinin (C).
