{HEAD ~ The medium} may be used for {TAIL ~ serum free culture} or supplemented with low levels of serum 
used for
{ HEAD ~ The medium } may be used for { TAIL ~ serum free culture } or supplemented with low levels of serum
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH