Initiation may be achieved by adding a blood coagulation factor {HEAD ~ XII activator} to animal plasma in {TAIL ~ the presence} of the test substance 
in
Initiation may be achieved by adding a blood coagulation factor { HEAD ~ XII activator } to animal plasma in { TAIL ~ the presence } of the test substance
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH