Fig. 4. 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 2 days after treatment. The cell number and the number of trypan blue-stained cells were determined 3 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 of each point is standard deviation. The bars not shown in figure were equal to sizes of symbols [28].