{TAIL ~ The retinoic acid} like activity of these compounds is confirmed through the classic measure of retinoic acid activity involving the effects of retinoic acid on {HEAD ~ ornithine decarboxylase} 
{ TAIL ~ The retinoic acid } like activity of these compounds is confirmed through the classic measure of retinoic acid activity involving the effects of retinoic acid on { HEAD ~ ornithine decarboxylase }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD