Bone Marrow Stem Cell Plasticity; Hematopoietic Stem Cells; Cell Lines as Models of as Stem Cells; Flow Cytometry and Stem Cell Isolation and Characterization; Murine embryonic Stem Cells; Mesenchymal Stem Cells; Differentiation of Stem Cells into Bone; Isolation of Cells from Bone Marrow Collection; Histology Marrow vs. Peripheral Blood; Lever Stem Cells; Stem Cells in CNS; Differentiation of Hemotopoietic Cells; Stem Cell Transplantation: Re-engineering the Immune System; Regulatory Perspective Regarding Stem Cells and Gene Therapy.