大鼠死后肝细胞核DNA的组织化学定量研究

推断死亡时间是法医学尸体检验须解决的重要问题之一。本实验用显微分光光度计定量测定了不同环境温度下（１０℃、２０℃、３０℃）大鼠死后不同时间肝细胞核ＤＮＡ平均含量，发现１０℃、２０℃、３０℃下大鼠死后肝细胞核ＤＮＡ含量与死亡时间呈负线性相关，其相关系数分别为—０．９９０５、—０．９８６３、—０．９７０２，且随环境温度升高ＤＮＡ含量的下降速度明显加快。作者认为ＤＮＡ组织化学定量技术可望成为推断死亡时间的新方法。     

The Effects of Sharp‐Force Thoracic Trauma on the Rate and Pattern of Decomposition

Given the multiple factors that may alter the rate of decomposition, one of the more difficult tasks that anthropologists and pathologists face is determining of the postmortem interval (PMI). While trauma has been widely accepted as being among those factors, recent published studies have contradicted this premise. However, major issues exist with these studies. Consequently, this study was designed to simulate a more realistic setting in an effort to settle this discrepancy in the literature. This study utilized eight porcine remains; three of which received incised wounds penetrating the thoracic cavity, three others received nonpenetrating wounds, and two were designated nontrauma controls. Measurements included evaluating the total body score (TBS) on temporal and accumulated degree days (ADD). Using a two‐way repeated measures ANOVA, the results of this study found that while trauma does have an influence in the pattern of decomposition, it does not influence the rate of decomposition.     

Utility of Postmortem Vitreous Beta-Hydroxybutyrate Testing for Distinguishing Sudden from Prolonged Deaths and for Diagnosing Ketoacidosis

A retrospective, cross-sectional analysis of vitreous beta-hydroxybutyrate (BHB) on 967 forensic cases over a two-year period was conducted. Cases were sorted into six categories of death: (i) sudden traumatic/non-natural (ST), (ii) sudden natural (SN), (iii) prolonged traumatic/non-natural (PT), (iv) prolonged natural (PN), (v) diabetic ketoacidosis (DKA), and (vi) alcoholic ketoacidosis (AKA). The mean BHB for all cases was 1.67 mmol/L (17.4 mg/dL; range: 0.11–18.02 mmol/L). The numbers of DKA, AKA, PN, PT, SN, and ST deaths were 21, 5, 155, 258, 275, and 253, respectively. Their mean vitreous BHBs were as follows: 11.04 mmol/L (DKA), 8.88 mmol/L (AKA), 1.56 mmol/L (PN), 1.55 mmol/L (PT), 1.26 mmol/L (SN), and 1.38 mmol/L (ST). There was a statistically significant difference between the mean BHBs of the PN and SN death groups (p < 0.001), as well as between those of the PT and ST death groups (p = 0.004). Given the overlapping ranges seen between the prolonged and sudden death groups, the identified differences did not hold clinical significance. In addition, we sought to determine a threshold value for vitreous BHB to definitely diagnose cases of ketoacidosis. BHB threshold concentrations between 2.5 and 5 mmol/L produced sensitivities >92% and specificities >96%. A receiver operator characteristic curve found 3.43 mmol/L to be the optimal cutoff value, demonstrating a specificity of 98.3% and a sensitivity of 96.2%.     

Fatal Spontaneous Retropharyngeal Hematoma with Airway Obstruction in the Setting of Treatment with Dipyridamole

We report a fatal case of airway obstruction caused by spontaneous retropharyngeal hematoma (RH) in the setting of treatment with dipyridamole. A 90-year-old woman presented with cervical swelling, neck and chest ecchymoses, and complaints of dyspnea. She suffered cardiopulmonary arrest in the ambulance, and her death was confirmed after transportation to the hospital. The major finding of postmortem computed tomography (PMCT) prior to autopsy was widening of the prevertebral soft tissue. The results of the autopsy indicated that the cause of death was mechanical asphyxia, secondary to pharyngeal and laryngeal compression caused by the RH. There were no evident injuries, medical interventions, or particular diseases, suggesting the spontaneous cause of the RH. To the best of our knowledge, this is the first report of a fatal case secondary to spontaneous RH that was revealed through PMCT imaging.     

Variation in decomposition stages and carrion insect succession in a dry tropical climate and its effect on estimating postmortem interval

Insects have an important role in minimum postmortem interval (PMI_min) estimation. An accurate PMI_min estimation relies on a comprehensive study of the development and succession of local carrion insects. No published research on carrion insect succession exists for tropical north Queensland. To address this, we aimed to obtain preliminary observational data concerning the rate of decomposition and insect succession on pig carcasses in Townsville and compare these with other regions of Australia and overseas. Adult insects were collected daily from three pig carcasses for 30 d during summer and identified to family level. Observations of decomposition rate were made each day and progression through the stages of decomposition were recorded. Adult insects were identified to family and their presence/absence used as a proxy for arrival at/departure from the remains, respectively. These preliminary data highlight several interesting trends that may be informative for forensic PMI_min estimation. Decomposition was rapid: all carcasses were at the dry/remains stage by Day 5, which was substantially quicker than all other regions in the comparison. Differences were also observed in the presence/absence of insect families and their arrival and departure times. Given the rapid progression through early decomposition, we argue that later-arriving coleopteran taxa may be more forensically informative in tropical Australia, in contrast with temperate regions where Diptera appear most useful. This research contributes preliminary observational data to understanding insect succession patterns in tropical Australia and demonstrates the critical need for comprehensive local succession data for each climatic region of Australia to enable accurate PMI_min estimation. These data will inform future research targeted at gaining a more comprehensive understanding of insect succession in the Australian tropics.

Key points:

• We obtained preliminary observational data concerning the rate of decomposition and insect succession on pig carcasses in tropical Australia.
• Decomposition was rapid: all carcasses were at the dry/remains stage by Day 5.
• Coleopteran taxa may be more forensically informative in tropical Australia than dipterans.

     

Cuticular hydrocarbons as a tool for determining the age of Chrysomya rufifacies (Diptera: Calliphoridae) larvae

Calliphoridae are one of the most important insect groups encountered as evidence collected from a crime scene. Age determination of the immature stages of these necrophagous flies is an important step toward estimating the time of colonization and inferring a minimum postmortem interval (PMI_min) in most instances. To determine if the cuticular hydrocarbons could be used to establish whether the development stages yield characteristics profiles, allowing for age estimation, hydrocarbons were extracted from 1st and 2nd, as well as feeding and post‐feeding 3rd instar Chrysomya rufifacies, the hairy maggot blow fly. Extracted hydrocarbons were analyzed using gas chromatography coupled to mass spectrometry with the aim to investigate the changes in chemical profiles of each larval stage. A total of 23 compounds were identified with most of them being alkanes (65%) with carbon chain lengths of 9–33 carbons, alkenes (18%), and methyl‐branched alkanes (17%). All the hydrocarbons except pentadecane (C15), hexadecane (C16), and nonacosane (C29) showed significant differences in their expression throughout larval development. For 1st instars, nonane was the most abundant (17% of the total hydrocarbons content) compound. Accounting for 11% and 10% of the cuticular hydrocarbons, tricosane and pentacosane, respectively, were the notable hydrocarbons in 2nd instars. For post‐feeding 3rd instars, hentriacontane and tritriacontane were present with relative abundances 18% and 15%, respectively. On average, there was a shift from low to high molecular weight hydrocarbons as the larvae aged. These results indicate the change in hydrocarbons makeup as larvae age and could potentially be used to determine the age of immature C. rufifacies and hence aid in PMI_min estimations. However, future research is needed to validate these results under natural conditions in the field.     

The effects of drying the rinsed dissected heart on postmortem heart weight

Blood and blood clots should be removed from the heart chambers before being weighed. The actual method in removing blood and blood clots may vary and can include manual removal with subsequent rinsing the heart in water. It is unclear whether drying the rinsed heart affects the heart weight. The objective of this article was to investigate the effects drying the rinsed dissected heart (residual rinsing water) on postmortem heart weight. The prospective study compared 44 dissected heart weights after being rinsed and after being pat dried. An average 18–20 g of residual rinsing water (4% of heart weight) was present in the dissected heart. The amount of residual rinsing water correlates positively with heart weight. The effects of drying the rinsed dissected heart were considered clinically insignificant. Although being clinically insignificant, this study highlights the lack of standardized approach in weighing the heart and the potential implications in interpreting heart weights.     

Storm‐Related Postmortem Damage to Skeletal Remains

In April 2011, human skeletons were exposed to heavy storms at the outdoor Anthropology Research Facility (ARF) in Knoxville, Tennessee. Of the approximate 125 skeletons at the ARF in April 2011, 30 donations exhibited postmortem damage that could be attributed to the storms. At least 20 of the affected donations exhibit postmortem damage clearly associated with hailstones due to the oval shape and similar small size of the defects observed. The irregular shape and larger size of other defects may be a product of other falling objects (e.g., tree branches) associated with the storms. Storm‐related damage was observed throughout the skeleton, with the most commonly damaged skeletal elements being the scapula and ilium, but more robust elements (i.e., femora and tibiae) also displayed characteristic features of hailstone damage. Thus, hailstone damage should be considered when forensic practitioners observe unusual postmortem damage in skeletal remains recovered from the outdoor context.     

猪眼玻璃体液钾离子、次黄嘌呤浓度变化与PMI推断

目的 研究猪眼玻璃体液成分变化及其与死亡时间(postmortem interval,PMI)的关系.方法放血处死家猪后取带眼睑的眼球96只,随机分为24组,在避光、温度(15±2)℃、湿度(50±5)%条件下分别放置2～96h,采集玻璃体液,运用全自动生化检测仪、超高效液相色谱检测K+、Na+、Cl-及次黄嘌呤(hy...