Comparative Analysis of Insect Succession Data from Victoria (Australia) Using Summary Statistics versus Preceding Mean Ambient Temperature Models

Minimum postmortem interval (mPMI) can be estimated with preceding mean ambient temperature models that predict carrion taxon pre‐appearance interval. But accuracy has not been compared with using summary statistics (mean ± SD of taxon arrival/departure day, range, 95% CI). This study collected succession data from ten experimental and five control (infrequently sampled) pig carcasses over two summers (n = 2 experimental, n = 1 control per placement date). Linear and exponential preceding mean ambient temperature models for appearance and departure times were constructed for 17 taxa/developmental stages. There was minimal difference in linear or exponential model success, although arrival models were more often significant: 65% of linear arrival (r² = 0.09–0.79) and exponential arrival models (r² = 0.05–81.0) were significant, and 35% of linear departure (r² = 0.0–0.71) and exponential departure models (r² = 0.0–0.72) were significant. Performance of models and summary statistics for estimating mPMI was compared in two forensic cases. Only summary statistics produced accurate mPMI estimates.     

Use of Postmortem Temperature Decay Response Surface Plots of Heat Transport in the Human Eye to Predict Time of Death

A finite element heat transfer model of the human eye was previously constructed and applied to experimental postmortem temperature decay curves collected in eyeballs of ten human bodies. The model was applied in the early postmortem period of 0–24 h under conditions of natural convection–radiation. Based upon this previous model, response surfaces for postmortem temperature decay were constructed based upon variable ranges of the natural convective–radiation heat transfer coefficient from 7–13 W/m² K, ambient temperatures of 10–33°C, and times of 0–24 h. Mathematical equations to describe these response surfaces have been developed. This response surface method is demonstrated for use by coroners/medical personnel to estimate time of death from recorded field temperature data collected over a 30‐min period. Sensitivity of the model to small changes in the key variable of ambient temperature is explored. The response surface model is applied to two cases of previously collected experimental eyeball temperature data. This response surface model method is only valid for constant surrounding temperatures, conditions of natural convection, no radiation effects, and postmortem times of 0–24 h.     

人体死亡后血液中生化指标的变化

目的测定人体死亡后血液中生化指标的变化并进行分析。方法收集81例交通事故死亡后尸体锁骨下静脉血样,并采用罗氏cobasc311全自动生化分析仪检测血液中肝功能（ALT、AST、TBIL、DBIL）、肾功能（UA、Cr）、心功能（CK、CK—MB、LDH）、电解质（K＋、Na＋、Cl-）以及葡萄糖（GLU）13项生化指标的变化,采用SPSS17．0统计学软件进行描述性分析。结果生化指标中ALT、AST、CK、CK—MB、LDH、D数值较活体正常参考值高、波动幅度较大。TBIL、DBIL、UA、Cr、Na＋、Cl-、GLU数值相对稳定、波动幅度较小。结论人体死亡后血液生化指标中肝功能、肾功能、心功能、电解质以及葡萄糖等指标易受溶血、自溶等因素影响,表现为生化指标升高明显,尤以酶类为著,且标准差较大。     

Potential Use of Hydrocarbons for Aging Lucilia sericata Blowfly Larvae to Establish the Postmortem Interval

Previous studies on Diptera have shown the potential for the use of cuticular hydrocarbons' analysis in the determination of larval age and hence the postmortem interval (PMI) for an associated cadaver. In this work, hydrocarbon compounds, extracted daily until pupation from the cuticle of the blowfly Lucilia sericata (Diptera: Calliphoridae), have been analyzed using gas chromatography–mass spectrometry (GC–MS). The results show distinguishing features within the hydrocarbon profile over the period of the larvae life cycle, with significant chemical changes occurring from the younger larvae to the postfeeding larvae. Further interpretation of the chromatograms using principal component analysis revealed a strong correlation between the magnitudes of particular principal components and time. This outcome suggests that, under the conditions of this study, the cuticular hydrocarbons evolve in a systematic fashion with time, thus supporting the potential for GC–MS analysis as a tool for establishing PMI where such a species is present.     

Evaluation of Postmortem Bacterial Migration Using Culturing and Real‐Time Quantitative PCR

Postmortem bacteriology can be a valuable tool for evaluating deaths due to bacterial infection or for researching the involvement of bacteria in various diseases. In this study, time‐dependent postmortem bacterial migration into liver, mesenteric lymph node, pericardial fluid, portal, and peripheral vein was analyzed in 33 autopsy cases by bacterial culturing and real‐time quantitative polymerase chain reaction (RT‐qPCR). None suffered or died from bacterial infection. According to culturing, pericardial fluid and liver were the most sterile samples up to 5 days postmortem. In these samples, multigrowth and staphylococci were not or rarely detected. RT‐qPCR was more sensitive and showed higher bacterial positivity in all samples. Relative amounts of intestinal bacterial DNA (bifidobacteria, bacteroides, enterobacter, clostridia) increased with time. Sterility of blood samples was low during the studied time periods (1–7 days). The best postmortem microbiological sampling sites were pericardial fluid and liver up to 5 days after death.     

Seasonal Variation of Carcass Decomposition and Gravesoil Chemistry in a Cold (Dfa) Climate

It is well known that temperature significantly affects corpse decomposition. Yet relatively few taphonomy studies investigate the effects of seasonality on decomposition. Here, we propose the use of the Köppen‐Geiger climate classification system and describe the decomposition of swine (Sus scrofa domesticus) carcasses during the summer and winter near Lincoln, Nebraska, USA. Decomposition was scored, and gravesoil chemistry (total carbon, total nitrogen, ninhydrin‐reactive nitrogen, ammonium, nitrate, and soil pH) was assessed. Gross carcass decomposition in summer was three to seven times greater than in winter. Initial significant changes in gravesoil chemistry occurred following approximately 320 accumulated degree days, regardless of season. Furthermore, significant (p < 0.05) correlations were observed between ammonium and pH (positive correlation) and between nitrate and pH (negative correlation). We hope that future decomposition studies employ the Köppen‐Geiger climate classification system to understand the seasonality of corpse decomposition, to validate taphonomic methods, and to facilitate cross‐climate comparisons of carcass decomposition.     

Age Estimation Based on Pulp Cavity to Tooth Volume Ratio Using Postmortem Computed Tomography Images

Pulp cavity size is known to decrease with age and can therefore serve as an indicator for age estimation. Here, we evaluated whether reconstructed images of multidetector‐row computed tomography (MDCT) acquired before forensic autopsy are useful for estimating age at death. Images of 136 mandibular first premolars obtained from bodies of known age at death were analyzed, and the volume of the regions corresponding to pulp cavity and that of the whole tooth were determined using a voxel counting function. The pulp cavity was clearly distinguishable from dental hard tissue on the reconstructed images when using a cutoff value of 1400 Hounsfield units. Regression analysis adjusted for sex showed that estimated age correlated significantly with the pulp cavity to tooth volume ratio (r = 0.76). MDCT is gaining more widespread use in forensic medicine, and analyzing dental images to obtain parameters for age prediction is a practical approach for postmortem identification.     

Deaths Involving Methylenedioxypyrovalerone (MDPV) in Upper East Tennessee

Two deaths involving 3, 4‐methylenedioxypyrovalerone (MDPV) are reported. MDPV is a synthetic cathinone stimulant found in “bath salts” with neurological and cardiovascular toxicity. Biological specimens were analyzed for MDPV by GC/MS and LC/MS. A White man was found dead with signs of nausea and vomiting after repeatedly abusing bath salts during a weekend binge. Femoral venous blood and urine had MDPV concentrations of 39 ng/mL and 760 ng/mL. The second fatality was a White man with a history of drug and bath salt abuse found dead at a scene in total disarray after exhibiting fits of anger and psychotic behavior. Femoral venous blood and urine had MDPV concentrations of 130 ng/mL and 3800 ng/mL. The blood and urine MDPV concentrations are within the reported recreational concentration ranges (blood 24–241 ng/mL and urine 34–3900 ng/mL). Both decedents’ deaths were attributed to relevant natural causes in a setting of MDPV abuse.     

Carbon Monoxide Poisoning and Death in a Large Enclosed Ventilated Area

A 55‐year‐old man with a medical history of tobacco use suddenly collapsed while power washing an empty indoor pool in a hotel. The decedent was transported to the local hospital where he was pronounced. A postmortem examination revealed atherosclerotic heart disease and bilateral pulmonary edema and congestion. A postmortem blood carbon monoxide (CO) level was 27% saturation, and a CO performed on hospital admission blood was 49% saturation. CO poisoning is a common cause of toxicological morbidity and mortality in the United States. The circumstances most often occur in an enclosed environment and may be intentional or unintentional. CO poisoning has been reported in open, well‐ventilated spaces, but rarely results in death. A warning label was present on the engine clearly stating the dangers of CO emission. However, there was a false sense of security due to the large size of the pool room and the presence of industrial blowers that were being used for ventilation.     

Internal Morphological Analysis for Age Estimation of Blow Fly Pupae (Diptera: Calliphoridae) in Postmortem Interval Estimation*

Abstract: Larvae and pupae of blow fly species are frequently used in postmortem interval estimation, their age indicating minimum time since death. Most studies have considered age estimation of larvae, neglecting study of pupae. Relative development of external pupal features is useful, but there are also internal changes during metamorphosis that may be indicators of age, utilizing histological techniques. This study aimed to optimize preservation and histological analysis of blow fly pupae, specifically Calliphora vicina Robineau‐Desvoidy and Lucilia sericata (Meigen), and to examine internal features with potential for age estimation. Effect of hot‐water‐killing and different preservatives were examined. It was determined that blow fly pupae should be pierced through the three tagma, hot‐water‐killed, and preserved in 80% ethanol as the optimal preservation for subsequent analyses. Hematoxylin and eosin stained pupal sections revealed differences in brain and thoracic muscle development throughout the pupal stage with potential for age estimation.