The cryopreserved tissue may be stored for {HEAD ~ indefinite periods} of {TAIL ~ time} prior to use 
of
The cryopreserved tissue may be stored for { HEAD ~ indefinite periods } of { TAIL ~ time } prior to use
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH