Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2002.770.773MiahM. Idrish7200257A study has been performed on the temperature dependence of the light exposure of human leukemic cells when treated with the photosensitizing agent δ-aminolevulinic acid, (ALA). The cells were incubated with 1mM ALA for 4h at different temperatures (31-45°C) and irradiated with different light doses in the blue spectral region (430nm). The dose-response curves were studied. Shoulders at the lower exposure regions were observed in the log-survival curves for incubation temperatures 31-37°C. The threshold dose values for the temperatures for which the shoulders had appeared were found to be 3.9, 3.2, 2.2, and 1.6min. for 31, 33, 35 and 37°C incubation temperatures, respectively. The phototoxic effect for the cells with these critical values was small. The activation energy for overcoming the shoulder reactions was 25kcal/mol. An activation energy of 9kcal/mol calculated for the cell type might be for the uptake of ALA by cells or protoporphyrin IX (PPIX) production in cells.]]>Ades, I.Z.,199022565574Arakane, K., A. Ryu and C. Hayashi,1996223578582Berg, K., J.C. Bommer, J.W. Winkelman and J. Moan,1990meso-tetraphenylporphyrins.]]>52775781Bogorad, L.,19791979Dahle, J., H.B. Steen and J. Moan,199970363367Dahle, J., S. Bagdonas, O. Kaalhus, G. Olsen, H.B. Steen and J. Moan,20001475273280Dailey, H.A.,19901990pp: 123-162pp: 123-162Dietel, W., K. Bolsen, E. Dickson, C. Fritsch, R. Pottier and R. Wendenburg,199633225231Gottfried, V. and S. Kimel,19918419430Hilf, R., J.J. Havens and S.L. Gibson,199970334340Jacob, G., M.N. Curzer and B.J. Fuller,1985in vitro freezing.]]>22417426Jordan, P.M.,19901990pp: 55-122pp: 55-122Juzenas, P., R. Sorensen, V. Iani and J. Moan,199969478481Kennedy, J.C., R.H. Pottier and D.C. Pross,19906143148Kennedy, J.C. and R.H. Pottier,199214275292Ma, L.W., E. Bjorklund and J. Moan,1999138197201Melo, T.B., G. Reisæter and A. Johnsson,1985Propionibacterium acnes porphyrins.]]>40125128Miah, M.I.,200162237240Miah, M.I.,200111720Miah, M.I., 200212127Moan, J., K. Berg, O.B. Gadmar, V. Iani, L. Ma and P. Juzenas,199970669673Patrice, T., M.T. Foultier, D. Cloarec and L.L. Bodic,19791979Peng, Q., K. Berg, J. Moan, M. Kongshaug and J.M. Nesland,199765235251Wyld, L., J.L. Burn, M.W.R. Reed and N.J. Brown,199776705712