{TAIL ~ These anthracycline analogs} show {HEAD ~ high cytotoxicity} in vitro against several tumor cell lines 
{ TAIL ~ These anthracycline analogs } show { HEAD ~ high cytotoxicity } in vitro against several tumor cell lines
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH