Abstract: The invention features retina-derived (retinal endothelial or retinal epithelial pigment) cell lines with extended life-span and capable of being implanted in the retina and of carrying a therapeutic substance to the eye and to the central nervous system. Such lines can also be used as a model for studying blood central nervous system interfaces. These lines are derived from primary retinal cultures selected from the group consisting of primary retinal endothelial cells and primary retinal epithelial cells, comprise a polynucleotide containing an oncogene, which polynucleotide is optionally associated with at least one selection gene, and have the morphological characteristics and at least the expression characteristics of the surface antigens of corresponding primary cultures.

Abstract: The invention features immortalized retina-derived (retinal endothelial or retinal epithelial pigmentary) cell lines capable of being implanted in the retina and of carrying a therapeutic substance to the eye and to the central nervous system. Such lines can also be used as a model for studying blood central nervous system interfaces. These lines are derived from primary retinal cultures selected from the group consisting of primary retinal endothelial cells and primary retinal epithelial cells, comprise a nucleic acid fragment containing at least one immortalizing fragment of a heat-sensitive viral oncogene, which nucleic fragment is optionally associated with at least one selection gene, and have the morphological characteristics and at least the expression characteristics of the surface antigens of corresponding primary cultures.

Abstract: A permselective graft polymer is disclosed that is formed by converting into intermediate reactive sites a portion of the cyano groups of a backbone polymer containing —CH2—CH(—C≡N)— units, and grafting polyalkylene oxide polymer chains to the backbone polymer through the reactive sites. Either the backbone polymer of a polymer resin or a permselective polymer membrane can be grafted. When a resin is used, it is formed into a permselective polymer membrane using known methods. The resulting permselective membrane can be formed into hollow fibers or flat sheets for the encapsulation of living cells. The encapsulated cells are then implanted into a patient in need of the biologically active factors produced by the cells. The permselective graft polymer membrane exhibits good molecular diffusion with minimal protein adsorption.