title: Estimation of postmortem interval using kinetic analysis of the third component of complement (C3) cleavage.
abstract: To estimate postmortem interval (PMI), spontaneous cleavage of the third component of complement (C3) was studied in aged blood and cadaveric blood by crossed immunoelectrophoresis. Using the kinetics of C3 cleavage in vitro described as dC/dt = -kC, where C is the concentration of native C3 at time t and k is a first-order rate constant, Arrhenius' equation, and another equation which assumes a linear drop of body temperature after death, the percentages of C3 cleavage were calculated. There was a significant positive correlation between the calculated percentages and the measured percentages of up to 10% in cadaveric blood. We found that the comparison between the calculated percentage of C3 cleavage for each optional postmortem interval and the measured percentage of up to 10% in cadaveric blood leads to the estimation of PMI. This approach is one step towards the development of an accurate method for determining PMI based on C3 cleavage, that is, on a first-order reaction.
authors.affiliation: Department of Legal Medicine, University of Tsukuba, Ibaraki-ken, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kominato
authors.forename: K
authors.initials: K
authors.lastname: Kumada
authors.forename: K
authors.initials: K
authors.lastname: Yamazaki
authors.forename: S
authors.initials: S
authors.lastname: Misawa
mesh_terms: D001797:Blood Protein Electrophoresis; D002423:Cause of Death; D003176:Complement C3 / Q000032:analysis*; D005554:Forensic Medicine / Q000379:methods*; D006801:Humans; D011180:Postmortem Changes; D013696:Temperature; D013997:Time Factors
chemical_list: D003176:Complement C3