complement system human 12 article 10 anticoagulation 6 calcium ion 6 controlled study 6 ionic strength 6 nonhuman 6 precipitation 6 priority journal 6 Animals 4 Anticoagulants 4 C1 4 Calcium 4 Complement C1 4 Complement system 4 Heparin 4 Human 4 Humans 4 Male 4 Molecular interactions 4 Osmolar Concentration 4 Precipitation 4 Structure-Activity Relationship 4 animal experiment 4 anticoagulant agent 4 antithrombin 4 glycosaminoglycan 4 heparin 4 male 4