Fetal movement during delivery can lead to damage to the umbilical vessels and endanger the life of the fetus.

INTRODUCTION: Fetal umbilical cord hematoma has a low incidence but high mortality, and its cause during delivery is often unclear. We report an autopsy case in which it was concluded that umbilical cord hematoma resulted from fetal movements during childbirth. CASE PRESENTATION AND AUTOPSY FINDINGS: A 27-year-old primigravida at 39 + 2 weeks gestation with normal antenatal visits suffered a fetal heart rate decrease during active labor. Bedside ultrasound revealed fetal death in utero 22 min later. Forensic pathologists found that the umbilical vessels were torn and bleeding on almost the same plane, and the hematoma compressed both umbilical arteries, which is the cause of fetal stillness in utero. A total of 32 cases were reported, including 6 umbilical cord ruptures and 26 umbilical cord hematomas. The cause of hematoma was unknown in 77 % of cases, while dysplasia was present in 56.25 % of umbilical cords. DISCUSSION: This case indicates that fetal movements may cause umbilical cord vessel injury, particularly when oxytocin is used to induce labor. When fetal heart sounds decrease for no apparent reason, the possibility of cord injury should be considered, and cesarean delivery should be performed as soon as possible. Therefore, rigorous fetal heart tracing during active delivery is necessary.

8-oxoguanine DNA glycosylase-1 may serve as biomarker of mechanical asphyxia.

AIM: To identify mtDNA and OGG1 as potential biomarker candidates for mechanical asphyxia. METHOD: The human tissues are divided into experimental group (hanging and strangulation) and control groups (hemorrhagic shock, brain injury group, and poisoning group). Detected the expression of OGG1 and integrity of mtDNA in cardiac tissue of each group. We used over-OGG1 vector and siRNA-OGG1 transfecting H9C2 cell line to observe the function of OGG1 in hypoxic cells. RESULTS: 1. mtDNA integrity decreased in the mechanical asphyxia group, OGG1 expression increased in mechanical asphyxia groups. They can be biomarkers for mechanical asphyxia. 2. OGG1 increased first and decreased in hypoxia-induced H9C2 cells. OGG1 upregulated the TFAM, NRF1, and Bcl2 in hypoxia-induced H9C2. OGG1 downregulated cleaved-Caspase3 in hypoxia-induced H9C2 cells. 3. In the normoxia condition, NAC maintained mtDNA integrity and decreased the mitochondrial membrane potential and amount of ATP. CONCLUSION: mtDNA integrity and OGG1 expression can be biomarkers for mechanical asphyxia. OGG1 can maintain mtDNA integrity and maintain the stability of the mitochondrial membrane.

Analysis of road traffic accidents and casualties associated with electric bikes and bicycles in Guangzhou, China: A retrospective descriptive analysis.

Introduction: Electric bicycles (e-bikes) and bicycles in large Chinese cities have recently witnessed substantial growth in ridership. According to related accident trends, this study analyzed characteristics and spatial distribution in the period when e-bike-related accidents rapidly increased to propose priority measures to reduce accident casualties. Methods: For e-bike- and bicycle-related accident data from the Guangzhou Public Security Traffic Management Integrated System, linear regression was used to examine the trends in the number of accidents and age-adjusted road traffic casualties from 2011 to 2021. Then, for the period when e-bike-related accidents rapidly increased, descriptive statistics were computed regarding rider characteristics, illegal behaviors, road types, collision objects and their accident liability. One-way analysis of variance (ANOVA) followed by Bonferroni's multiple comparison test. P < 0.05 was considered statistically significant. Finally, the density distribution of accidents was presented, and Moran's I (MI) was used for assessing spatial autocorrelation. Hotspots were identified based on an optimized hotspot analysis tool. Results: Between 2011 and 2021, the number of accidents and casualty rate (per 100,000 population) increased for e-bikes but decreased for bicycles. After 2018, e-bike-related accidents increased rapidly, and bicycle-related accidents plateaued. Accident hotspots were concentrated in central city areas and suburban areas close to the former. Three-quarters of accidents occurred in motorized vehicle lanes. Most occurred on roads without physically segregated nonmotorized vehicle lanes. More than three-fifths of the accidents involved motor vehicles with at least four wheels. The prevalence (per 100 people) of casualties among e-bike rider victims and cyclist victims accounted for 92.0 % and 96.5 %, respectively. A total of 71.6 % of e-bike-related accidents involved migrant workers. Riding in motorized vehicle lanes was the most common illegal behavior. Conclusions: Although e-bike-related and bicycle-related accidents presented similar characteristics, the sharp increase in e-bike-related accidents requires attention. To improve e-bike safety, governments should develop appropriate countermeasures to prevent riders from riding on motorways, such as improving road infrastructure, adjusting the driver's license system and addressing priority control areas.

Parametric analysis of craniocerebral injury mechanism in pedestrian traffic accidents based on finite element methods.

PURPOSE: The toughest challenge in pedestrian traffic accident identification lies in ascertaining injury manners. This study aimed to systematically simulate and parameterize 3 types of craniocerebral injury including impact injury, fall injury, and run-over injury, to compare the injury response outcomes of different injury manners. METHODS: Based on the total human model for safety (THUMS) and its enhanced human model THUMS-hollow structures, a total of 84 simulations with 3 injury manners, different loading directions, and loading velocities were conducted. Von Mises stress, intracranial pressure, maximum principal strain, cumulative strain damage measure, shear stress, and cranial strain were employed to analyze the injury response of all areas of the brain. To examine the association between injury conditions and injury consequences, correlation analysis, principal component analysis, linear regression, and stepwise linear regression were utilized. RESULTS: There is a significant correlation observed between each criterion of skull and brain injury (p < 0.01 in all Pearson correlation analysis results). A 2-phase increase of cranio-cerebral stress and strain as impact speed increases. In high-speed impact (> 40 km/h), the Von Mises stress on the skull was with a high possibility exceed the threshold for skull fracture (100 MPa). When falling and making temporal and occipital contact with the ground, the opposite side of the impacted area experiences higher frequency stress concentration than contact at other conditions. Run-over injuries tend to have a more comprehensive craniocerebral injury, with greater overall deformation due to more adequate kinetic energy conduction. The mean value of maximum principal strain of brain and Von Mises stress of cranium at run-over condition are 1.39 and 403.8 MPa, while they were 1.31, 94.11 MPa and 0.64, 120.5 MPa for the impact and fall conditions, respectively. The impact velocity also plays a significant role in craniocerebral injury in impact and fall loading conditions (the p of all F-test < 0.05). A regression equation of the craniocerebral injury manners in pedestrian accidents was established. CONCLUSION: The study distinguished the craniocerebral injuries caused in different manners, elucidated the biomechanical mechanisms of craniocerebral injury, and provided a biomechanical foundation for the identification of craniocerebral injury in legal contexts.

Arrhythmia onsets triggered by acute myocardial ischemia are not mediated by lysophosphoglycerides accumulation in ventricular myocardium.

Lysophosphoglycerides (LPLs) have been reported to accumulate in myocardium and serve as a cause of arrhythmias in acute myocardial ischemia. However, in this study we found that LPLs level in the ventricular myocardium was decreased by the onset of acute myocardial ischemia in vivo in rats. Decreasing of LPLs level in left ventricular myocardium, but not right, was observed within 26 min of left myocardial ischemia, regardless of whether arrhythmias were triggered. Lower LPLs level in the ventricular myocardium was also observed in aconitine-simulated ventricular fibrillation (P < 0.0001) and ouabain-simulated III° atrioventricular block (P < 0.0001). Shot-lasting electric shock, e.g., ≤ 40 s, decreased LPLs level, while long-lasting, e.g., 5 min, increased it (fold change = 2.27, P = 0.0008). LPLs accumulation was observed in long-lasting myocardial ischemia, e.g., 4 h (fold change = 1.20, P = 0.0012), when caspase3 activity was elevated (P = 0.0012), indicating increased cell death, but not coincided with higher frequent arrhythmias. In postmortem human ventricular myocardium, differences of LPLs level in left ventricular myocardium was not observed among coronary artery disease- and other heart diseases-caused sudden death and non-heart disease caused death. LPLs level manifested a remarkable increasing from postmortem 12 h on in rats, thus abolishing the potential for serving as biomarkers of sudden cardiac death. Token together, in this study we found that LPLs in ventricular myocardium were initially decreased by the onset of ischemia, LPLs accumulation do not confer arrhythmogenesis during acute myocardial ischemia. It is necessary to reassess the roles of LPLs in myocardial infarction.

Overview of road traffic injuries among migrant workers in Guangzhou, China, from 2017 to 2021.

INTRODUCTION: There are many migrant workers in China's first-tier cities, but little is known about road safety. This paper systematically analysed road traffic injuries and risk factors among migrant workers in Guangzhou, China. METHODS: Road traffic crash data from 2017 to 2021 were obtained from the Guangzhou Public Security Traffic Management Integrated System. We plotted the crash network of road users in road traffic crashes and used logistic regression to analyse the risk factors for migrant workers of motorcycle and four-wheeled vehicle crashes. Moreover, the roles of migrant workers and control individuals as perpetrators in road traffic crashes were also analysed. RESULTS: Between 2017 and 2021, 76% of road traffic injuries were migrant workers in Guangzhou. Migrant workers who were motorcyclist drivers most commonly experienced road traffic injuries. Crashes between motorcyclists and car occupants were the most common. The illegal behaviours of migrant worker motorcyclists were closely related to casualties, with driving without a licence only and driving without a licence and drunk driving accounting for the greatest number. Migrant workers were responsible for many injuries of other road users. Motorcycle drivers have a higher proportion of drunk driving. DISCUSSION: Migrant workers play an important role in road traffic safety. They were both the leading source of road traffic injuries and the main perpetrators of road traffic crashes. Measures such as strict requirements for migrant workers to drive motorcycles with licences, prohibit drunk driving, greater publicity of road safety regulations, and combining compulsory education with punishment for illegal behaviours.

The down-regulation of STC2 mRNA may serve as a biomarker for death from mechanical asphyxia.

Death from mechanical asphyxia (DMA) is a common cause of death in forensic pathology. However, due to the lack of biomarkers, the authentication of DMA now relies on a series of non-specific signs, which may cause troubles in the judicial trials, especially when the criminal scene is not fully elucidated. To search for the potential biomarkers for DMA, brain samples of DMA and craniocerebral injury groups were screened by microarray. The obtained mRNAs were validated by animal and human samples. Primary cell culture was conducted to explore the biochemical changes under hypoxia. 415 differentially expressed mRNAs between two groups were discovered. Ten mRNAs were examined in both human and animal samples died of different causes of death. Stanniocalcin-2 (STC2) showed significant down-regulation in DMA samples compared to other groups, regardless of PMI, age, or temperature. Cellular experiments indicated that ROS level peaked after 15-min-hypoxic culture, when the expression level of STC2 was significant down-regulated simultaneously. The ER-stress-related proteins also showed potential connection with STC2. In general, it is indicated that the down-regulation of STC2 may serve as a biomarker for DMA.

Pulmonary fat embolism: a potentially new fatal complication of SARS-CoV-2 infection. A case report.

BACKGROUND: So far, there have been more than 761 million confirmed cases of SARS-CoV-2 worldwide, with more than 6.8 million deaths. The most common direct causes of death for COVID-19 are diffuse alveolar injury and acute respiratory distress syndrome. Autopsy results have shown that 80-100% of COVID-19 patients have microthrombi which is 9 times higher than in patients with influenza. There are reported cases of fat embolism associated with Covid-19, but relevant epidemiological investigations and fatal cases of pulmonary fat embolism are lacking. In this report, we describe the first COVID-19 patient to die from pulmonary fat embolism. CASE PRESENTATION: A 54-year-old woman suddenly felt unwell while at work. She had difficulty breathing for 40 min and lost consciousness for 20 min before being taken to the hospital. On admission, her temperature was 36 ℃, but her respiration, heart rate, and blood pressure were undetectable. Laboratory examination revealed C-reactive protein, 26.55 mg/L; D-dimer, 11,400 µg/L; and procalcitonin, 0.21 ng/mL. She was declared clinically dead 2 h after admission due to ineffective rescue efforts. At autopsy, both lungs were highly oedematous with partial alveolar haemorrhage. The presence of microthrombi and pulmonary fat embolism in small interstitial pulmonary vessels was confirmed by phosphotungstic acid haematoxylin staining and oil red O staining. The immunohistochemical results of spike protein and nucleocapsid protein in laryngeal epithelial cells confirmed SARS-CoV-2 infection. CONCLUSIONS: Pulmonary fat embolism may be another fatal complication of COVID-19 infection, and clinicians should pay more attention to it.

Research Progress on Molecular Changes in Pulmonary Hypoxia and Cause of Death Identification in Mechanical Asphyxia.

Lung is the largest organ of the respiratory system. During hypoxia, pulmonary cells undergo rapid damage changes and activate the self-rescue pathways, thus leading to complex biomacromolecule modification. Death from mechanical asphyxia refers to death due to acute respiratory disorder caused by mechanical violence. Because of the absence of characteristic signs in corpse, the accurate identification of mechanical asphyxia has always been the difficulty in forensic pathology. This paper reviews the biomacromolecule changes under the pulmonary hypoxia condition and discusses the possibility of application of these changes to accurate identification of death from mechanical asphyxia, aiming to provide new ideas for related research.

Death from Pulmonary Embolism Caused by Vaginal Injection of Hyaluronic Acid: a Case Report and a Literature Review.

A 40-year-old woman underwent vaginoplasty with intramural injection of fillers from an illegal medical practitioner. Approximately 2 h after the injection, she developed lower abdominal pain. The patient was taken to the hospital approximately 5 h later due to worsening pain. When the patient was admitted for physical examination, she suddenly experienced cardiac and respiratory arrest. She was resuscitated but remained in a coma. Unfortunately, the patient died approximately 12 h after being admitted to the hospital. The forensic autopsy revealed extensive amorphous basophilic emboli in the small interstitial vascular lumen of both lungs, and a large amount of the same type of substances were also found in the vaginal wall. Hyaluronidase digestion and Alcian blue staining confirmed that most components of the injection were hyaluronic acid (HA). HA is widely used as a cosmetic filler in the field of plastic surgery and is generally considered to have few adverse effects. This paper reports the first anatomical case of fatal pulmonary embolism caused by vaginal injection of HA. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .