Estimation of time since death
University of Bonn, Bonn, North Rhine-Westphalia, Germany Forensic Science International
(Impact Factor: 2.14).
02/2007; 165(2-3):182-4. DOI: 10.1016/j.forsciint.2006.05.017
The main principle of the determination of the time since death is the calculation of a measurable date along a time-dependent curve back to the start point. Characteristics of the curve (e.g. the slope) and the start point are influenced by internal and external, antemortem and postmortem conditions. These influencing factors have to be taken into consideration quantitatively in order to improve the precision of death time estimation. It does not make any sense to study the postmortem time course of any analyte without considering influencing factors and giving statistical parameters of the variability. Comparison of different methods requires an investigation of the same postmortem interval. For practical purposes, it must be concluded that the amount of literature on estimating the time since death has a reverse correlation with its importance in practice.
Available from: Carlo P Campobasso
- "In deeper experiments, pig carcasses were skeletonized in less than a month due to animal activity whereas for shallow carcasses the remains were not skeletonized for many weeks . It has been noted  that most of the scientific papers dealing with PMI as well as PMSI estimation as case studies on human remains or animal models " have never gained any practical relevance since they do not meet the demands in practice (being precise, reliable and giving an "
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ABSTRACT: The study of decomposition by using accumulated degree days (ADDs) has been suggested not only in terrestrial decay but also for water-related deaths. Previous studies have demonstrated that the accumulation of thermal energy as a function of the post-mortem submersion interval (PMSI) can be derived from a descriptive decompositional scoring system (DSS). In order to verify how useful can the total aquatic decomposition score (TADS) for ADD prediction be, a comparative taphonomic study has been performed between two series of bodies: 16 corpses found floating in shallower waters with a presumptive PMSI from 3 to 118 days and exposed to water temperatures (Tw) between 10.5 and 20.3 °C approximately equating from a minimum of 46 to 1.392 ADD; 52 bodies, all victims of a single shipwreck, found in sequestered environments and subjected to constant Tw of 4 °C for 210 days approximately equating to 840 ADD. The two series of bodies have revealed different stages of decay and a large DSS variability. In most of bodies, freshly formed adipocere was able to delay the appearance of later decompositional stages explaining why most of the bodies were in relatively good condition. Although promising, the accuracy of the TADS model can be affected by adipocere and animal activity. The TADS model suffers of the same limitations for ADD calculations as they can give a false perception of accuracy due to the complexity of integrating all changing factors affecting human decay in sequestered and non-sequestered marine environments (currents, animal activity, water temperatures, depth of submersion).
Available from: sciencedirect.com
- "The difficulty is related to the absence of data related to timedependent postmortem changes associated with factors such as body structure, cause of death, climate, drug addiction, disease, and so forth   , especially ambient temperature  . Viable quantitative measurements and mathematical description play an important role in eliminating or weakening the affecting factors in the determination of PMI . Screening for chemical changes post mortem is feasible in principle, and meets practical requirements. "
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ABSTRACT: 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.
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.
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).
Interpolation function is an appropriate choice for PMI estimation by weakening influence of ambient temperature.
Available from: link.springer.com
- "In this study, we applied a metabolomics approach to the problem of the post-mortem interval as it pertains to the field of forensic science. The typical methods used in postmortem-interval studies entail observation of changes of dental tissues, rigor mortis and body temperature (Coe 1993; Di Maio and Di Maio 2001; Henssge and Madea 2007; Kaliszan et al. 2009). However, as these are applicable only after a considerable amount of time has passed post-mortem, precision and accuracy are lost. "
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ABSTRACT: Metabolomics technology, employed in the analysis of low-molecular endogenous metabolites (e.g., by NMR, LC/MS, GC/MS) and with statistical algorithms, has been applied to the development of new drugs, the diagnosis of diseases, and a variety of other fields. In the present research, certain endogenous metabolite candidates with which, by application of metabolomics to forensic science, post-mortem changes can be inferred were postulated. We combined UPLC/Q-TOF MS-based metabolomics with a statistical analysis to search for metabolite changes related to the post-mortem interval. Metabolites extracted from the livers of rats 0, 24, and 48 h post-sacrifice were analyzed by UPLC/Q-TOF MS. After acquiring the exported UPLC/Q-TOF MS data, PCA, PLS-DA, OPLS-DA and R were applied to identify the significantly up/down regulated metabolites. Comparing the postulated metabolites list with the Human Metabolome Database (HMDB: http://www.hmdb.ca), we could classify samples for post–mortem-interval prediction.
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