Radiation modifying effects of meso-tetraphenyl porphyrins.

: The radiation modifying effects of a series of the metal chelates of meso-tetra(p-carboxyphenyl) porphine has been investigated using a human lymphoid cell line, RPMI 1788. These studies revealed that Ni and Zn porphyrins were effective radiation sensitizers at concentrations as low as 10-9M. Further studies with Zn porphyrin showed it to be almost equally effective when added immediately after irradiation and partially effective when added up to 90 minutes post irradiation, suggesting that it may be acting by interfering with a repair mechanism.