{HEAD ~ A defined regimen} of media changes are used to establish a quiescent and nonproductive state following the withdrawal of {TAIL ~ the antiviral treatment} 
{ HEAD ~ A defined regimen } of media changes are used to establish a quiescent and nonproductive state following the withdrawal of { TAIL ~ the antiviral treatment }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL