Abstract: Injectable hydrogels comprising polysaccharides based on disaccharides the backbones of which form an ?-helix structure and in which in at least 10% of the disaccharide units the primary hydroxyl groups are oxidized.

Abstract: The invention is directed to a method for producing precursor cells expressing a target gene, for example VEGF, at desired levels comprising stably transducing precursor cells with the target gene linked to a cell-surface marker gene, for example truncated CD8/CD8a, via an IRES sequence accommodating translation of the target and the marker genes from the same mRNA, then correlating an expression level of the target gene with that of the cell-surface marker gene, selecting a reference clone of cultured precursor cells expressing the target gene at the desired threshold, and isolating precursor cells having the same or similar level of expression of the target gene than the reference clone.

Abstract: Compositions for co-expression of VEGF and PDGF at a desired ratio, and their methods of use, are provided.