prion prion disease prion diseases prion protein prion proteins prions prior prior administrative prior agreement prior agreements prior analysis prior and informed prior and informed consent prior application prior appointment prior appraisal prior approval prior arrangement prior arrangements prior arrests prior arrival prior art prior art can prior art device prior art devices prior art document prior art documents prior art does prior art does not prior art has prior art have prior art includes prior art method prior art process prior art processes prior art references prior art system prior art systems prior art techniques prior assessment prior attempts prior audit prior authorisation prior authorization prior booking prior checking prior chemotherapy prior claim prior commitment prior commitments prior condition prior conditions prior consent prior consultation prior contact prior conviction prior convictions prior criminal record prior declaration prior distribution prior engagement prior experience prior experiences prior exposure prior fiscal prior general prior generations prior history prior information prior information notice prior informed prior informed consent prior informed consent procedure prior judicial prior knowledge prior known prior learning prior learning assessment prior marriage prior medical prior method prior military prior month prior notice prior notification prior occasions prior period prior permission prior planning prior preparation prior probability prior provincial prior publication prior quarter prior record prior registration prior relationship prior request prior research