Hematopoiesis assay

Molecules that damage or affect normal bone marrow functions may induce immunotoxicity as well, since bone marrow is the site of hematopoiesis. Clinical manifestations of drug-induced myelotoxicity include peripheral pancytopenia if stan cells or all hematopoietic lineages are involved or anemia, leukopenia, and/or thrombocytopenia, if only specific lineages are affected (Carey, 2(X)3 Evans, 2008). Typical bone marrow culture assays focus on granulocyte, monocyte, megakaryocyte, and/ or erythroid lineages. Lymphopoiesis can be evaluated by other functional assays such as lymphocyte proliferation assays, which may include assessment of proliferation of individual lymphoid subsets. For more details on assessment of bone marrow toxicity, please see ChapterIV.il. 

Transgenic Embryo Explant Culture Assay for Induction of Hematopoiesis by Non-Mesodermal Signals... 

To establish more directly that visceral endoderm is required for induction of hematopoiesis in the gastrulating embryo, tissue recombination experiments were performed. A semi-quantitative RT-PCR protocol was used to assay for activation of the endogenous mouse embryonic p-like globin genes (15), Ectoderm and VE layers from individual embryos were cultured separately or in combination for two to four days. RNA was prepared from individual explants and analyzed for embryonic globin gene activation using the RT-PCR assay. 

Might the molecules responsible for respecification of cell fate observed in the reprogramming assay be distinct from those involved in activation of hematopoiesis from nascent posterior mesoderm in vfvol The induction (epiblast explant) assay presumably reflects what occurs in vivo, while the reprogramming (anterior ectoderm) assay reflects the potential activity of visceral endoderm signals. Anterior ectoderm is normally fated to form neurectoderm, not blood or endothelial cells. 

In early 1987 we proved that the bryostatins were capable of stimulating normal bone marrow progenitor cells to form colonies in vitro and to activate neutrophils (68). Bryostatin 1, e.g., promotes many of the biological effects of GM-CSF and this remarkable activity combined with its antineoplastic activity make it a very attractive clinical candidate. Meanwhile, bryostatins 1 and 2 have found an important role as biochemical probes for unraveling the mechanisms of normal hematopoiesis (69). An important advance here was the observation that bryostatin 1 will stimulate normal erythropoiesis in human bone marrow progenitor assays. Furthermore, bryostatin 1 approximated the stimulatory effects of IL-3 on both murine normal and w/w bone marrow... 

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