A method 8, wherein {HEAD ~ the washing medium} is the culture medium used in {TAIL ~ stage}  
A method 8 , wherein { HEAD ~ the washing medium } is the culture medium used in { TAIL ~ stage }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH