DNA methylation of the NR3C1 promoter region in brains of pediatric victims of physical abuse.

Early life stress (ELS) has been suggested to cause epigenetic changes to genes in the brain, such as the Nuclear Receptor Subfamily 3, Group C, Member 1 gene (NR3C1). Conversely, evaluation of the epigenetic status in the postmortem brain might provide clues to the antemortem ELS experience. We examined DNA methylation of the 1F promoter region of NR3C1 in the postmortem brains of eight children including four ELS cases. As a result, DNA methylation was evident in ELS cases due to severe physical abuse. Epigenetic status may have potential application as a biomarker for clarifying the antemortem experiences of deceased.

Distinguishing true from pseudo hematoma in the cervical spinal canal using postmortem computed tomography.

Spinal cord injury is difficult to detect directly on postmortem computed tomography (PMCT) and it is usually diagnosed by indirect findings such as a hematoma in the spinal canal. However, we have encountered cases where the hematoma-like high-attenuation area in the cervical spinal canal was visible on PMCT, while no hematoma was observed at autopsy; we called it a "pseudo hematoma in the cervical spinal canal (pseudo-HCSC)." In this retrospective study, we performed statistical analysis to distinguish true from pseudo-HCSC. The cervical spinal canal was dissected in 35 autopsy cases with a hematoma-like high-attenuation area (CT values 60-100 Hounsfield Unit (HU)) in the spinal canal from the first to the fourth cervical vertebrae in axial slices of PMCT images. Of these 22 had a hematoma and 13 did not (pseudo-HCSC). The location and length of the hematoma-like high-attenuation and spinal cord areas were assessed on reconstructed PMCT images, true HCSC cases had longer the posterior hematoma-like area and shorter the spinal cord area in the midline of the spinal canal (P < 0.05). Furthermore, we found that true HCSC cases were more likely to have fractures and gases on PMCT while pseudo-HCSC cases were more likely to have significant facial congestion (P < 0.05). We suggest that pseudo-HCSC on PMCT is related to congestion of the internal vertebral venous plexus. This study raises awareness about the importance of distinguishing true HCSC from pseudo-HCSC in PMCT diagnosis, and it also presents methods for differentiation between these two groups.

Quantitative analysis of respiratory viral distribution in forensic autopsy cases.

Respiratory viruses can cause fatal systemic infections; therefore, post-mortem diagnosis is essential in forensic autopsy cases. However, little is known regarding the distribution of respiratory viruses in the body. In this study, we investigated the anatomical distribution of respiratory viruses in 48 forensic autopsy cases suspected of viral infections at our institute. Fast Track Diagnostics (FTD) Respiratory Pathogens 21 was used as a screening test for 20 respiratory viruses in nasopharyngeal swabs. In cases with positive results for virus detection by the screening test, the detected viruses were quantified in body fluid and organ specimens by virus-specific real-time reverse transcription polymerase chain reaction (RT-PCR) and digital PCR. Viruses were detected in 33 cases, with the viral distribution and load differing among the cases. Since various respiratory viruses were detected from the nasopharyngeal swab and its viral load was higher than those of other body fluid specimens, the nasopharyngeal swab was suggested as a useful specimen for the post-mortem detection of respiratory viruses. Viruses were detected in almost all specimens including the serum in six cases. Considering the viral distribution in the body, pathological findings, and ante-mortem symptoms, these cases were presumed to be systemically infected, having died in the acute infection phase. In conclusion, the anatomical distribution of respiratory viruses can help indicate ante-mortem systemic conditions and the cause of death.

Kinetics and distribution of benzalkonium compounds with different alkyl chain length following intravenous administration in rats.

Benzalkonium chloride is widely used in disinfectants. Several toxicological and fatal cases have been reported; however, little is known about its kinetics and distribution. We investigated the kinetic characteristics and distribution of benzalkonium cation (BZK) based on the length of the alkyl chains C12, C14, and C16. Rats were treated intravenously with BZK solution (dose, 13.9 mg/kg) containing equal amounts of the three homologues. Kinetic parameters in the blood were assessed, and BZK distribution in the blood and tissues was examined both in rapid intravenous (IV) and drip intravenous (DIV) administrations. BZK concentrations were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). BZK with longer alkyl chains showed lower elimination tendencies and remained in the blood for a longer duration. Concentrations of BZK were higher in the heart, lung, spleen, and kidney than those in the blood, and lower in the brain and fat. In both the IV and DIV groups, the lung, liver, spleen, and fat samples showed higher concentrations of the longer alkyl chains (BZK-C12 < -C14 < -C16), and the opposite trend was observed in the kidney (BZK-C16 < -C14 < -C12). Only the heart and muscle samples displayed the homologues in ratios comparable to the original administered solutions. Differences between IV and DIV groups could be identified by comparing concentrations of BZK homologues in the heart, lung, spleen, and kidney samples. We found that the kinetics and distribution of BZK were influenced by the alkyl chain length, and analysing each BZK homologues in blood and tissue samples may provide useful information.

Identification of aortic injury site using postmortem non-contrast computed tomography in road traffic accident.

In high-speed motor vehicle accidents, it is necessary to investigate the manner of death. Postmortem computed tomography (PMCT) provides important information on the mechanism of death, but identification of the aortic injury is still challenging on non-contrast PMCT. A man in his 50s had multiple injuries on the face and chest in the high-speed motor vehicle accident. The traumatic aortic rupture was clearly depicted on thin-slice and multiplanar reformation PMCT images. Traumatic aortic disruption was confirmed by forensic autopsy. The high contrast between the aortic wall and the lumen visualized the traumatic rupture in the distal aortic arch. For the evaluation of aortic rupture on PMCT, it may be important to trace the continuity of the high-density aortic wall by reviewing thin-slice CT and multiplanar reformation images.

Use of postmortem computed tomography angiography to detect vascular injuries accompanying skull base fracture.

A 58-year-old woman who had presented for upper gastrointestinal barium examination accidently slipped from the movable bed, and her head became compressed between the end of the bed and the side wall. She suffered massive bleeding from her nose and ear followed by cardiac arrest, and subsequent attempts at cardiopulmonary resuscitation failed. A medicolegal autopsy was performed to reveal the cause of death, as part of the investigation of the accident. During the autopsy, postmortem cerebral CT angiography was carried out by injection of 5% gelatin-barium emulsion as a radiopaque contrast medium into the bilateral common carotid arteries, demonstrating transudation of the contrast medium into the right acoustic meatus and the sphenoidal sinus cavity. Considering that the body appeared anemic and that PMCTA suggested vascular injuries, the cause of death was definitively determined to be hemorrhagic shock due to injuries to the right internal carotid artery, accompanied by skull base fracture. Postmortem CT angiography played an important role in confirming that the vascular injuries had been responsible for the bleeding, as the lesions could not be fully confirmed by native CT or macroscopic examination.

Characterization of five cases of suspected bathtub suicide.

We reviewed five autopsy cases of suspected bathtub suicide. The immediate cause of death in all cases was determined to be drowning on the basis of macropathological findings such as frothy fluid in the airways or overinflation of the lungs as well as histological findings obtained at autopsy. We suspected that the manner of death in those cases was suicide based on comprehensive postmortem investigations of statements from witnesses, the presence of a farewell letter, the fact that clothes had been worn, additional means to ensure suicide, and results of drug tests, as well as autopsy findings. Cases of bathtub suicide should be investigated carefully to distinguish them from accidental or natural death.