title: Interpolation function estimates post mortem interval under ambient temperature correlating with blood ATP level.
abstract: OBJECTIVE
  We developed a mathematical model using interpolation function, to characterize the correlation between blood ATP levels in the right ventricle of rabbit and post mortem interval (PMI) at different ambient temperatures.
  
  
  METHODS
  Forty-eight healthy rabbits were randomly divided into 6 groups of 8 each. The sacrificed rabbits were maintained in calorstats at 10°C, 15°C, 20°C, 25°C, 30°C and 35°C, respectively. Blood from the right ventricle was sampled every 4h until 72h after death. At different time points, ATP concentrations in the blood samples were measured using an ATP fluorescence rapid detector, and then displayed on the detector screen in the form of relative light units (RLU). Relationship between PMI and ATP degradation levels was investigated statistically by SPSS 17.0 and MATLAB 10.0 software.
  
  
  RESULTS
  We obtained six regression equations (Ra(2)=0.887-0.929) with RLU values at PMIs of 72h (10°C), 60h (15°C), 56h (20°C), 52h (25°C), 40h (30°C) and 32h (35°C), and an interpolation function (Ra(2)=0.930) was established with PMI as the dependent variable (z), RLU value as independent variable (x) and temperature as independent variable (y).
  
  
  CONCLUSIONS
  Interpolation function is an appropriate choice for PMI estimation by weakening influence of ambient temperature.
authors.affiliation: Department of Forensic Medicine, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Tingyi
authors.initials: T
authors.lastname: Sun
authors.affiliation: Collaborative Innovation Center of Judicial Civilization, Beijing 100040, China; Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing 100040, China.
authors.forename: Tiantong
authors.initials: T
authors.lastname: Yang
authors.affiliation: Collaborative Innovation Center of Judicial Civilization, Beijing 100040, China; Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing 100040, China.
authors.forename: Haidong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Forensic Medicine, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Luo
authors.initials: L
authors.lastname: Zhuo
authors.affiliation: Department of Forensic Medicine, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China. Electronic address: sty_j211@126.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Liu
mesh_terms: D000255:Adenosine Triphosphate / Q000097:blood*; D000818:Animals; D006352:Heart Ventricles; D023421:Models, Animal; D015233:Models, Statistical; D011180:Postmortem Changes; D011817:Rabbits; D012044:Regression Analysis; D062206:Spatial Analysis; D013696:Temperature
chemical_list: D000255:Adenosine Triphosphate
keywords: Adenosine triphosphate; Forensic pathology; Forensic science; Interpolation function; Post mortem interval