protocol for the treatment of each cell line was the same in each experiment as follows 1 cells were seeded 800 cells well 100 u03bcl into plates 96 wells each with the hct8 fl2h cells pretreated with about 200 u03bcm 5 fu and 20 u03bcm leucovorin lv for 2 hours then cultured 10 times in the presence of 20 u03bcm lv which procedure was repeated 10 times 2 some wells were treated individually with a mtx b mdam c 5 fu and d s 1 concentrations of each compound used are described in the tables supra 3 some wells were treated with a co administered dosage of mtx 5 fu mtx s 1 mdam 5 fu or mdam s 1 the exact procedures and concentrations of each drug are described in the tables 4 some wells were treated with one of the mtx or mdam 5 fu or s 1 combinations see 3 for a predetermined period of time after which the drugs were removed and the well treated with mdam or mtx individually 5 cell counts were recorded for each well by a standard cell counting device and percentage of cells surviving was measured since the doubling rate for.