Fig. 6. Neuroblastoma cells (NBP2) (50,000 per dish) were plated in tissue culture dishes (60 mm), and vincristine and aqueous preparation of vitamin E (dl--tocopheryl acetate) were added 24 hours later. Drugs and medium were changed two days after treatment. The cell number and the number of trypan blue-stained cells were determined three days after treatment. The number of stained cells was subtracted from the total number of cells to obtain viable cells per dish. The average of control cultures was considered 100%. Each value represents an average of at least six samples. The bar at each point is standard deviation. The bars not shown in figure were equal to sizes of symbol [1].