Sequential Changes of Total Adenine Nucleotide and Adenylic-Acid Energy Charge in Muscles of Rats after Death / 法医学杂志

Objective To determine the purine adenylate [adenosine triphosphate （ATP）, adenosine diphosphate （ADP）, adenosine monophosphate （AMP）] content in the muscles of both hind limbs of rats at different postmortem interval （PMI）, calculate the changes in the total adenine nucleotide （TAN） content and the adenylic-acid energy charge （AEC）, and explore their relationship with PMI. Methods Healthy rats were sacrificed by cervical dislocation and kept at 20 ℃. The muscles of their hind limbs were extracted at 0, 24, 48, 72, 96, 120, 144, and 168 h after death. Reversed-phase high performance liquid chromatography was used to determine the content of purine adenylates, the TAN and AEC of the muscles of the both hind limbs were calculated, and the related regression equations of their relationship with PMI were established. Results Within 168 h of death of rats, the trend of ATP change was different from ADP, and the content of AMP continuously increased. The TAN value gradually increased with the extension of PMI, and the AEC showed a downward trend within 168 h after death. Among them, the patterns of AEC changes with PMI were obvious, the correlation coefficient was high （ R2=0.903）, and the curve fitting relationship was good; the fitting relationship between ATP, ADP, AMP, TAN and PMI was poor （ R2=0.198-0.754）. Conclusion The postmortem change patterns of AEC provide new research ideas for PMI estimation in the forensic field.

Research Progress on Accumulated Degree Days for PMI Estimation / 法医学杂志

Among many factors that affect postmortem interval （PMI）, temperature is undoubtedly the most important factor, but simply considering temperature in estimation of PMI has limitations. Accumulated degree days （ADD） is an important indicator related to biological growth and development, which considers two major variables, environmental temperature and elapsed time. Therefore, the establishment of mathematical model of ADD and some evaluation indicators to estimate PMI, is obviously better than single temperature variable. This article briefly describes the research history of ADD, its application in PMI estimation, and the problems it faces, to provide reference for the further development of ADD to improve the accuracy of PMI estimation.