the 50 % retinoid dose ( dose effective in achieving a response in half of the organ cultures ) that inhibited invasion was 0.85 micrograms/ml of retinol palmitate , 0.39 micrograms/ml of retinoic acid , or 0.16 micrograms/ml of retinol acetate .
C0035339
retinoid
C0040845
retinoic acid