Influence of Paraquat on Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) Infesting Minced‐beef Substrates in Kelantan,Malaysia

This study investigated the influence of paraquat, a prevalent poison used by suicides, on initial oviposition and development of Chrysomya megacephala (Fabricius) using minced‐beef substrates. Paraquat in lethal dose for human (40 mg/kg), two times the lethal dose (80 mg/kg) and five times the lethal dose (200 mg/kg) were mixed thoroughly with respective minced‐beef substrates (1 kg each) that were decomposed in a shaded habitat fully protected from rain. Results of four replications of the above experiment revealed that the presence of paraquat neither delayed initial oviposition nor prolonged the developmental stages of C. megacephala. Therefore, estimation of postmortem interval (PMI) based on empirical baseline data obtained using animal models devoid of any poisons would still be appropriate for estimating PMI in paraquat‐related deaths.     

Do bone elasticity and postmortem interval affect forensic fractographic analyses?

Forensic fractographic features of bone reliably establish crack propagation in perimortem injuries. We investigated if similar fracture surface features characterize postmortem fractures. Experimentally induced peri- and postmortem fractures were used to assess if fractographic features vary as bone elasticity decreases during the postmortem interval (PMI). Thirty-seven unembalmed, defleshed human femoral shafts from males and females aged 33–81 years were fractured at varying PMIs with a drop test frame using a three-point bending setup and recorded with a high-speed camera. Vital statistics, cause of death, PMI length, temperature, humidity, collagen percentage, water loss, fracture energy, and fractography scores were recorded for each sample. Results showed that fractographic features associated with perimortem fractures were expressed in PMIs up to 40,600 accumulated degree hours (ADH), or 60 warm weather days. Hackle was the most consistently expressed feature, occurring in all fractures regardless of ADH. The most variable characteristics were wake features (78.4%) and arrest ridges (70.3%). Collagen percentage did not correlate strongly with ADH (r = −0.04, p = 0.81); however, there was a strong significant correlation between ADH and water loss (r = 0.74, p < 0.001). Multinomial logistic regression showed no association between fractographic feature expression and ADH or collagen percentage. In conclusion, forensic fractographic features reliably determine initiation and directionality of crack propagation in experimentally induced PMIs up to 40,600 ADH, demonstrating the utility of this method into the recent postmortem interval. This expression of reliable fractographic features throughout the early PMI intimates these characteristics may not be useful standalone features for discerning peri- versus postmortem fractures.     

Technical and interpretive pitfalls of postmortem CT: Five examples of errors revealed by autopsy

Image acquisition of dead bodies, particularly using postmortem computed tomography (PMCT), has become common in forensic investigations worldwide. Meanwhile, in countries such as Japan which have an extremely low rate of autopsy, PMCT is being increasingly used in the clinical field to certify the cause of death (COD) without performing an autopsy or toxicological tests, even in cases of unnatural death. Additionally, these PMCT images are predominantly interpreted by clinical personnel such as emergency physicians or clinicians who are not trained in PMCT interpretation and who work for the police, that is, the so-called police doctors. Many potential pitfalls associated with the use of PMCT have been previously described in textbooks and published papers, including the pitfalls of not performing a complete forensic pathology investigation, and the use of physicians without appropriate PMCT training to interpret PMCT and direct death investigation and certification. We describe five examples in which apparent misdiagnosis of COD based on PMCT misinterpretation was revealed by autopsy. Here are the five examples of errors: (1) Postmortem changes were misinterpreted as COD, (2) resuscitation effects were misinterpreted as COD, (3) COD was determined after an incomplete examination, (4) fatal findings caused by external origin were wrongly interpreted as ‘of internal origin’ based on PMCT, and (5) non-fatal findings on PMCT were wrongly interpreted as fatal. Interpretation of PMCT by appropriately trained physicians and an accompanying complete forensic investigation, including autopsy when indicated, is necessary to prevent significant errors in COD determination and related potential adverse medicolegal consequences.     

Dental hygiene students' matching accuracy when comparing antemortem dental radiographs and oral photographs to simulated postmortem WinID3® odontograms

Matching dental antemortem (AM) and postmortem (PM) data for human identification is especially challenging when the workforce is limited. Dental hygienists have served mass fatality incidents (MFIs) due to dental-related expertise. However, forensics within dental hygiene education and research on transferable skills is limited. This qualitative balance design study assessed senior dental hygiene students' match accuracy of simulated cases varying in dental identifiers based on AM full mouth series (FMS) radiographs and oral photographs to PM WinID3^® odontograms to demonstrate possible disaster victim identification (DVI) transferable skills gained during formal education. A convenience sample of senior dental hygiene students (n = 31) was presented information on WinID3^® interpretation, then presented with 5 mismatched cases and asked to visually interpret each to make 10 total matches; five based on AM FMS with simulated PM WinID3^® odontograms and five based on AM photographs with PM WinID3^® odontograms. Match accuracy scores ranged from 41.9% to 58.1% for cases with 1–10 identifiers, and 77.4% to 93.5% for cases with 11–40 identifiers. Accuracy when matching AM radiographs to PM odontograms versus AM photographs to PM odontograms was compared and revealed no statistical differences in match accuracy depending on image type (p = 0.388 to 1.000). Results of this pilot study suggests transferable match accuracy skills resulted from the participants' dental hygiene formal education. These baseline skills with additional specialized training support the rationale for dental hygienists serving on DVI teams. More research is needed in education and practice when preparing dental hygienists for forensic-based service.     

Fatal intoxication involving 2-methyl AP-237

Novel synthetic opioids contribute considerably to the opioid epidemic, especially with the frequent emergence of structurally similar compounds. This case report describes a fatal intoxication involving 2-methyl AP-237. A 54-year-old Caucasian male was found deceased from an apparent drug overdose. A plastic container labeled “2MAP” and a cut straw were found in the decedent's backpack at the scene. A white substance found in the container tested positive for fentanyl by field testing. According to his medical history, the decedent was treated for a drug overdose 3 years prior to his death. With no diagnostic findings at autopsy, the case was submitted for toxicological analysis. An unknown substance was detected in peripheral blood and urine using gas chromatography with nitrogen phosphorous detection (GC-NPD). Further testing was conducted using gas chromatography–mass spectrometry (GC–MS) and liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) which confirmed the presence of 2-methyl AP-237 and potential metabolites in blood and urine. Quantitation by GC-NPD revealed concentrations of 2-methyl AP-237 in blood and urine at 480 ng/mL and 4200 ng/mL, respectively. The toxicological analysis also identified and quantitated alprazolam in the blood at 55 ng/mL. Additionally, the metabolism of 2-methyl AP-237 was investigated and three hydroxylated metabolites were identified in peripheral blood and urine. Limited literature is available for the detection and quantitation of 2-methyl AP-237 in postmortem specimens. Given the toxicological findings with unremarkable autopsy findings, this case is an example of a fatal intoxication involving 2-methyl AP-237.     

Evaluation of the Postmortem Glucose and Glycogen Levels in Hepatic,Renal, Muscle,and Brain Tissues: Is It Possible to Estimate Postmortem Interval Using These Parameters?

The aim of our study was to investigate the postmortem levels of glucose and glycogen in hepatic, renal, muscle, and brain tissues and then examine the changes in those levels that could be useful for estimating postmortem interval. We established an animal model. Seventy female BALB/c albino mice were used in this study. After being sacrificed, the mice were randomly divided into six groups according to time elapsed since death (Group 1: 0 h; Group 2: 12 h; Group 3: 24 h; Group 4: 36 h; Group 5: 48 h; and Group 6: 60 h). Glucose levels were significantly different between groups for all tissues studied. Slope of the change per unit time was higher for the hepatic glucose levels. Based on these results, it is possible to estimate postmortem interval using postmortem glucose levels in hepatic tissue. Tissue‐specific assessment may contribute valuable information to postmortem interval studies.     

Brain Fluid Content Related to Body Position and Postmortem Interval – An Animal Model

Adult male Sprague Dawley rats were euthanized and placed in a horizontal or vertical (head‐down) position at room temperature, after which brain fluid content was measured by a moisture analysis technique at variable time points. No significant difference in brain fluid content was observed between horizontal and vertical postmortem positions. A significant increase in brain fluid content was demonstrated 3, 6, and 24 h after death, with maximal fluid content observed at 24 h. Specifically, the brain fluid content of control animals was 77.79 ± 0.36%, increasing to 80.05 ± 0.22% at 24 h (p < 0.0001). This study has demonstrated no significant differences in brain fluid content related to postmortem position, suggesting that a head‐down position is not associated with increased brain fluid content or swelling. However, significant temporal increases in brain fluid content after death, most likely related to cerebral liquefaction, occur.     

Temperature‐Dependent Postmortem Changes in Human Cardiac Troponin‐T (cTnT): An Approach in Estimation of Time Since Death

Estimation of time of death is an indispensible requirement of every medico‐legal autopsy, but unfortunately, there is not a single method by which it could be determined accurately. This study focused on the temperature‐dependent postmortem degradation of cardiac troponin‐T and its association with postmortem interval (PMI) in human. The analysis involved extraction of the protein, separation by denaturing gel electrophoresis (SDS‐PAGE), and visualization by Western blot using cTnT‐specific monoclonal antibodies. The area of the bands within a lane was quantified by scanning and digitizing the image using Gel Doc (Universal Hood). The results indicate a characteristic banding pattern among human cadavers (n = 6) and a pseudo‐linear relationship between percentage of cTnT degradation and the log of the time since death (r > 0.95), which can be used to estimate the postmortem interval. The data presented demonstrate that this technique can provide an extended time range during which PMI can be more accurately estimated.     

Petechial Hemorrhages and Ethanol in Deaths from Intoxication

Petechiae in conjunctivae and in the palpebrae/skin of the eyelids are of particular interest for the forensic pathologist, because of their association with pressure on the neck. They have been described in the eyelids of intoxicated persons both in case reports and in text books of forensic pathology. We studied 590 deaths caused by intoxication, and 75 had petechiae either in the conjunctivae, the eyelids, or in both locations. We examined the influence of drugs and ethanol on the location of the petechial hemorrhages in these deaths. Deaths with ethanol in blood and in urine/vitreous humor more often had petechiae in both locations than those without. This association was statistically significant, independent of body position and livor mortis. No association between the location of petechiae, medicinal drugs, or narcotics was found. These results suggest that ethanol may contribute to the development of petechial hemorrhages in deaths from intoxication.     

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.