Fluorescence Imaging of Posterior Spiracles from Second and Third Instars of Forensically Important Chrysomya rufifacies (Diptera: Calliphoridae),

Entomological protocols for aging blowfly (Diptera: Calliphoridae) larvae to estimate the time of colonization (TOC) are commonly used to assist in death investigations. While the methodologies for analyzing fly larvae differ, most rely on light microscopy, genetic analysis, or, more rarely, electron microscopy. This pilot study sought to improve resolution of larval stage in the forensically important blowfly Chrysomya rufifacies using high‐content fluorescence microscopy and biochemical measures of developmental marker proteins. We established fixation and mounting protocols, defined a set of measurable morphometric criteria and captured developmental transitions of 2nd instar to 3rd instar using both fluorescence microscopy and anti‐ecdysone receptor Western blot analysis. The data show that these instars can be distinguished on the basis of robust, nonbleaching, autofluorescence of larval posterior spiracles. High‐content imaging techniques using confocal microscopy, combined with morphometric and biochemical techniques, may therefore aid forensic entomologists in estimating TOC.     

人体脑组织RNA表达水平与早期PMI的相关性

目的探讨人体脑组织多种RNA指标的表达水平与早期死亡时间(PMI)的相关性。方法选取12例已知PMI(4.3~22.5 h)的个体,提取脑组织总RNA。选取8种常用RNA指标(β-actin、GAPDH、RPS29、18S rRNA、5S rRNA、U6 snRNA、miRNA-9、miRNA-125b),通过实时荧光定量PCR技术检测其在脑组织中的表达水平。运用geNorm软件筛选早期PMI表达稳定的内参指标,并分析其表达水平与相关因素(年龄、性别、死亡原因)的关系。运用R软件将内参标准化的RNA指标代入前期研究建立的数学模型推断PMI,计算推断PMI的误差率以验证模型精确性。结果 5S rRNA、miRNA-9和miRNA-125b表达稳定,其表达水平与年龄、性别、死亡原因无关。利用β-actin推断PMI的误差率为24.6%,GAPDH为41.0%。结论 5S rRNA、miRNA-9和miRNA-125b在死亡早期表达稳定,适合作为人体脑组织的内参指标。β-actin表达水平与PMI相关性良好,有望成为推测早期PMI的辅助指标。     

Potential Forensic Application of Receptor for Advanced Glycation End Products (RAGE) as a Novel Biomarker for Estimating Postmortem Interval

Studies which estimate the postmortem interval (PMI) based on diatoms or bacterial communities have been well‐conducted. However, predicting the PMI based on microorganisms has limited accuracy. The objective of this study was to discover specific biomarkers for estimating the PMI for drowning. The in vivo experimental model consisted of rats classified into nine groups (seven drowned groups from Day 1 to Day 7 and two control groups). Their lung tissues were analyzed for the receptor for advanced glycation end products (RAGE) mRNA expression determined by qRT‐PCR. RAGE protein levels were determined by Western blotting and immunohistochemical (IHC) staining. RAGE mRNA and protein levels gradually degraded over time. Immunostaining analysis revealed that RAGE in the Day 1 sample was significantly higher than that in the Day 6 or Day 7 samples. These results indicate that RAGE in drowned lungs could be a potential biomarker for the determination of the PMI after drowning.     

Carbon‐Based Fingerprint Powder as a One‐Step Development and Matrix Application for High‐Resolution Mass Spectrometry Imaging of Latent Fingerprints

Carbon‐based materials are often used as matrices for matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) and its imaging (MALDI‐MSI). However, researchers have refrained from using carbon‐based fingerprint powder (CFP) as a matrix due to high background and contamination. In this work, the compatibility of CFP is reevaluated with MALDI‐MSI using a high‐resolution mass spectrometer (HRMS) and compared to traditional organic matrices. Relevant fingerprint compounds were easily distinguished from carbon cluster peaks when using HRMS. For fair comparison, half of a fingerprint was dusted with CFP while the other half was dusted with traditional organic matrices. All compounds studied had comparable, or higher, signal‐to‐noise (S/N) ratios when CFP was used as the matrix. Additionally, chemical image qualities closely followed the trend of S/N ratios. CFP proved to be an effective one‐step development and matrix application technique for MALDI‐MSI of latent fingerprints, when carbon cluster peaks are well separated by a HRMS.     

Cardiac Ventricular Laceration Due to Child Abuse: Abusive Ventricular Laceration

Traumatic cardiac ventricular ruptures in children are rare. Only a single case of left ventricular rupture due to child abuse has been reported. We report a child who sustained a fatal left ventricular apical rupture. It appeared to have resulted from hydrostatic forces resulting from abusive blunt thoracic injury. That he was being abused was previously missed when he was presented to the emergency department with facial pyoderma. It was not noted that he also had lip and oral mucosal injury, sites not affected by staph toxins. As a result, his underlying, abusive and secondarily infected, facial flow type scald burn was not appreciated. Within a week thereafter his fatal injury occurred, accompanied by extensive and obvious associated abusive injuries. Postmortem high‐detail whole body computed tomography scanning aided the autopsy. Although rare, ventricular rupture from abusive blunt thoracic injury can occur.     

Postmortem Analysis of Electrogram Records from an Implantable Cardioverter‐Defibrillator (ICD) in the Reconstruction of a Road Traffic Accident

The case of a 69‐year‐old man, equipped with an ICD and suffering from several chronic cardiac diseases, who died in a car accident, was presented. We analyzed electrogram records from the ICD explanted from the body during the autopsy, which showed that the driver had suffered from malignant ventricular arrhythmia—ventricular fibrillation (VF). A thorough analysis of the details of the accident, as well as the timing of VF and the rhythm observed after the discharge of the ICD showed that the direct cause of the accident was the episode of arrhythmia resulting in a loss of consciousness. Therefore, the presented case illustrates the usefulness of postmortem analysis of electrogram records from ICDs in the reconstruction of road traffic accidents. In such cases, if the victims are implanted with ICDs, it should be a routine procedure performed by forensic pathologists.     

An Anthropological Examination of the Types of Skeletal Fractures Resulting from Fatal High (˃3 m) Free Falls,

Fatal falls from heights (?3 m) often result in blunt force trauma (BFT) to the skeleton. The fracture patterns that result from this BFT mechanism are well understood in forensic anthropology and forensic pathology; however, details of the specific types of fractures that result remain poorly documented. The aim of this study was to provide a detailed examination of the types of fractures that may result from fatal high falls. Fractures were recorded from 95 full‐body postmortem computed tomography scans of individuals known to have died from a high fall. Trauma was then analyzed taking into account the extrinsic and intrinsic variables known to influence a fall using multiple logistic regression. A total of 339 types of fractures were classified, of which 16 were significantly associated with this BFT mechanism. Classified fracture types will augment anthropological interpretations of the circumstances of death from BFT in cases of suspected high falls.     

Comparative and Correlation Studies of Biochemical Substances in Vitreous Humor and Synovial Fluid

Vitreous humor (VH) and synovial fluid (SF) become optional postmortem samples for biochemistry investigation. However, few studies have explored SF as a potential source, and there is still controversy whether the biochemical concentrations in bilateral VH are the same. We explored the concentrations of biochemical substances in both VH and SF, and compared between both sides and between the fluids. We also correlated the biochemical concentrations in both fluids. All samples were centrifuged after collection and the supernatant fluids were used for the analysis. The results indicated no significant difference in the constituent concentrations between the fluids from both sides (p > 0.05). Sodium, potassium, chloride, and magnesium concentrations were significantly higher in the VH, but in vice versa for glucose, uric acid, and creatinine concentrations (p < 0.001). Sodium, potassium, glucose, lactate, urea, uric acid, and creatinine concentrations between both fluids showed significant correlation (p < 0.05), but not chloride and magnesium concentrations.     

An Aquatic Decomposition Scoring Method to Potentially Predict the Postmortem Submersion Interval of Bodies Recovered from the North Sea

This study aimed to develop an aquatic decomposition scoring (ADS) method and investigated the predictive value of this method in estimating the postmortem submersion interval (PMSI) of bodies recovered from the North Sea. This method, consisting of an ADS item list and a pictorial reference atlas, showed a high interobserver agreement (Krippendorff's alpha ≥ 0.93) and hence proved to be valid. This scoring method was applied to data, collected from closed cases—cases in which the postmortal submersion interval (PMSI) was known—concerning bodies recovered from the North Sea from 1990 to 2013. Thirty‐eight cases met the inclusion criteria and were scored by quantifying the observed total aquatic decomposition score (TADS). Statistical analysis demonstrated that TADS accurately predicts the PMSI (p < 0.001), confirming that the decomposition process in the North Sea is strongly correlated to time.