title: Charcoal-dextran treatment of fetal bovine serum removes an inhibitor of human CFU-megakaryocytes.
abstract: Serum has been shown to have an inhibitory effect on the growth of human megakaryocyte colony-forming units (CFU-Meg), both in the methylcellulose and plasma clot systems. Charcoal-dextran (CD) treatment of fetal bovine serum (FBS), a method that is known to adsorb free hormones and various other substances from their protein-bound counterparts, has been used for the improvement of human erythroid colony growth. We now report a CD treatment of FBS to improve human CFU-Meg growth, using a modified plasma clot colony assay. We found 22.9 +/- 1.9 (SEM) colonies in cultures containing CD-treated FBS, as compared to 7.1 +/- 0.9 colonies with control FBS (different at p less than or equal to 0.0001). Serum treated with dextran alone produced 5.0 +/- 1.6 colonies, which did not differ from control FBS. Cultures containing CD-treated human AB serum, human AB plasma, and citrated bovine plasma yielded significantly (p less than 0.05) fewer colonies than those with CD-treated FBS. Endotoxin, cortisol, T3, T4, insulin, estradiol, testosterone, and erythropoietin levels were not changed in a consistent direction by the CD treatment. Our treatment of FBS with CD allows improved growth of human CFU-Meg colonies and likely represents the removal of an as-yet-undefined inhibitor(s) of CFU-Meg. This technique provides the ability to assay for stimulators or potentiators less hampered by the influence of an undefined inhibitor(s).
mesh_terms: D000818:Animals; D002417:Cattle; D002606:Charcoal / Q000494:pharmacology*; D003115:Colony-Stimulating Factors / Q000037:antagonists & inhibitors*; D003911:Dextrans / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000032:analysis; D005312:Fetal Blood / Q000187:drug effects*; D006728:Hormones / Q000032:analysis; D006801:Humans; D008533:Megakaryocytes / Q000166:cytology*; D008722:Methods
chemical_list: D003115:Colony-Stimulating Factors; D003911:Dextrans; D004731:Endotoxins; D006728:Hormones; D002606:Charcoal