The Role of Protein Degradation in Estimation Postmortem Interval and Confirmation of Cause of Death in Forensic Pathology: A Literature Review.

It is well known that proteins are important bio-macromolecules in human organisms, and numerous proteins are widely used in the clinical practice, whereas their application in forensic science is currently limited. This limitation is mainly attributed to the postmortem degradation of targeted proteins, which can significantly impact final conclusions. In the last decade, numerous methods have been established to detect the protein from a forensic perspective, and some of the postmortem proteins have been applied in forensic practice. To better understand the emerging issues and challenges in postmortem proteins, we have reviewed the current application of protein technologies at postmortem in forensic practice. Meanwhile, we discuss the application of proteins in identifying the cause of death, and postmortem interval (PMI). Finally, we highlight the interpretability and limitations of postmortem protein challenges. We believe that utilizing the multi-omics method can enhance the comprehensiveness of applying proteins in forensic practice.

Characterization of a novel SCN5A mutation associated with long QT syndrome and arrhythmogenic right ventricular cardiomyopathy in a family.

Sudden cardiac death represents a significant diagnostic challenge for forensic pathologists, particularly in inherited arrhythmia syndromes or cardiomyopathies resulting from genetic defects. Molecular autopsies can reveal the underlying molecular etiology in such cases. In this study, we investigated a family with a history of sudden cardiac death to elucidate the molecular basis responsible for sudden cardiac death. The proband underwent a comprehensive forensic examination. Family members received thorough clinical evaluations, including electrocardiogram, Holter monitoring, echocardiography, and cardiac magnetic imaging. Whole exome sequencing and genetic analysis were performed on the deceased and her parents. In addition, Western blotting and patch-clamp recordings were employed to evaluate the expression and function of the mutant protein in vitro. Forensic examination diagnosed arrhythmogenic right ventricular cardiomyopathy (ARVC) as the cause of sudden death. Genetic analysis identified a novel missense mutation in SCN5A (p.V1323L), which was assessed as likely pathogenic by the ACMG guideline. Another family member carrying the mutation manifested long QT syndrome and mild cardiac fibrosis. The cellular electrophysiological study demonstrated that the mutation resulted in an enhanced late sodium current, suggesting it was a gain-of-function mutation. This study characterizes a novel SCN5A mutation that putatively causes long QT syndrome and may contribute to the development of ARVC. Our work expands the pathogenic spectrum of SCN5A variants and underscores the importance of molecular autopsy in sudden death cases, especially in those with suspected genetic disorders.

Genetic polymorphism and forensic efficiency of 21 autosomal STR loci from Shandong Han population in Northern China.

BACKGROUND: Highly polymorphic autosomal STR loci are useful for understanding population structure better and for forensic application, however the non-CODIS STR loci in the Han population of Shandong, located in Northern China, are not well-characterised. AIM: To investigate population genetic polymorphism and forensic efficiency of 21 autosomal STR loci from the Shandong Han population in Northern China and reveal the genetic relationships with other populations both at home and abroad. SUBJECTS AND METHODS: In this study, population genetic data of 21 autosomal STR loci included in the Goldeneye DNA ID 22NC Kit that includes four CODIS loci and 17 non-CODIS loci were determined for 523 unrelated Han individuals in Shandong. RESULTS: Significant deviations from Hardy-Weinberg equilibrium were not observed. A total of 233 alleles were detected with allele frequencies ranging from 0.0010 to 0.3728. The combined power of discrimination was 0.99999999999999999999999990011134, and the combined power of exclusion was 0.99999999788131. Furthermore, in an analysis of population differentiation Nei's standard genetic distance and multidimensional scaling analysis, which were conducted based on the overlapping 15 STR loci, revealed that the Shandong Han population was most closely related to populations in close geographic proximity. CONCLUSIONS: This study demonstrated that the 21 autosomal STR loci included in the GoldeneyeTM DNA ID 22NC system are highly polymorphic and suitable for forensic identification and paternity testing in the Shandong Han population. Additionally, the present results enrich the population genetic database.

Potential biomarkers in hypoglycemic brain injury.

Oxidative stress is a major underlying mechanism in hypoglycemic brain injury. Several oxidative stress-related proteins were identified through previous proteomics and literature review. The aim of the present study was to evaluate the potential of these proteins as biomarkers in hypoglycemic brain injury. Forty male Sprague Dawley rats were randomly and equally divided into four groups: control, acute hypoglycemia, hypoglycemia resuscitation 24 h, and hypoglycemia resuscitation 7 days. The hypoglycemic brain injury rat model was successfully constructed according to the Auer model. Real-time fluorescent quantitative polymerase chain reaction, western blot analysis, and immunohistochemical staining were used to quantify the expression of oxidative stress-related proteins. We also verified the expression level of selected protein in the brain samples of fatal insulin overdose cases. The expression of oxidative stress-related proteins PEX1/5/12 was down-regulated in hypoglycemic brain injury (P < 0.05), while the expressions of DJ-1 and NDRG1 were up-regulated (P < 0.05). Compared with the control group, the serum oxidative stress indexes SOD and MDA in the acute hypoglycemia group were significantly different (P < 0.01). The expressions of DJ-1 and NDRG1 in the hippocampus, cortex, and hypothalamus of rats were increased (P < 0.05). The expressions of DJ-1 and NDRG1 proteins in the cortex of the autopsy samples of insulin overdose were increased (P < 0.05). Oxidative stress-related proteins showed potential value as specific molecular markers in hypoglycemic brain injury, but further confirmatory studies are needed.

A rare case of respiratory failure associated with spinal cord injury caused by stabbing with scissors and a knife.

In forensic practice, spinal cord injury (SCI) resulting in death has rarely been reported. Here, we present the case of a 65-year-old woman who on admission was conscious without dyspnea or dysphagia. Physical examination revealed two sharp objects penetrating the neck: a pair of scissors lodged in the neck on the right side of the thyroid cartilage and a knife embedded in the nuchal region accompanied by minor seepage of bloody exudate. Radiography showed that the scissors and knife were retained in the cervical spine. Despite a series of medical interventions, the patient died 26 days later. METHOD: A systematic forensic autopsy was performed. RESULTS: The cause of death was confirmed to be respiratory failure associated with SCI, which was caused by the combination of scissors and a knife. CONCLUSION: Based on this case, we believe that when there are multiple causes of death, forensic pathologists should determine the primary, immediate, contributory, and other causes of death to ascertain criminal responsibility.

Acute water intoxication in hysteroscopic myomectomy: a rare case report.

Water intoxication is rarely seen in forensic practice and is typically associated with excessive water consumption, amphetamine intake, and child abuse. Iatrogenic water intoxication is rare but usually related to medical disputes. Here, we report a 44-year-old female was admitted to the hospital due to a 3-month history of excessive menstrual bleeding. B-ultrasound revealed multiple substantial intrauterine masses, leading to a diagnosis of multiple uterine fibroids. After admission, she underwent submucous myomectomy, endometrial resection, and transcervical resection of endometrial polyps. During the procedure, the patient suffered dizziness and chest tightness, her blood pressure decreased to 89/52 mmHg, and moist rales were heard in her both lungs; she died despite medical efforts. A forensic autopsy was performed and revealed severe pulmonary edema. Considering the patient's clinical history, acute water intoxication was considered to be the cause of death. This highlights the need for forensic pathologists to be vigilant of postoperative water intoxication, a rare complication in obstetrics, to ensure accurate assessments.

Four cases of fatal acute arsenic poisoning: histopathology, toxicology, and new trends.

Arsenic is a valuable component in tumor treatment and traditional Chinese medicine and has seen widespread use in processing, manufacturing, and agriculture. Although rare, arsenic poisoning can occur in forensic practice. Elusive pathological changes, as well as obscure clinical signs, may cause arsenic poisoning to go unrecognized. Here, we report four cases of fatal acute arsenic poisoning, with careful observation of pathological changes and collection of postmortem specimens for arsenic concentration analysis. Additionally, we reviewed six cases of fatal arsenic poisoning in the past 20 years. In the present study, microvesicular steatosis in the peripheral areas of the hepatic lobules and acute splenitis were observed, which are rare findings in acute arsenic poisoning. This study summarizes the histopathological features of arsenic poisoning and presents data on arsenic distribution. Arsenic concentrations in the liver and kidneys can increase the reliability of identifying arsenic poisoning. Furthermore, in traditional Chinese medicine-related deaths, arsenic poisoning needs more attention.

A novel frameshift mutation in Allan-Herndon-Dudley syndrome.

Allan-Herndon-Dudley syndrome (AHDS) is a very rare, X-linked psychomotor disability syndrome with delayed myelination, almost exclusively affecting boys. We present a case of a 4-year-old boy with AHDS who was found cyanotic, with intermittent vomiting and paroxysmal convulsions about 4 h after his parents went out, and was then taken to the hospital, where he eventually died the next day. The autopsy revealed foreign bodies in the tiny bronchi and alveoli of the deceased, congestion, and punctate hemorrhage in multiple organs, consistent with the diagnosis of asphyxia. Compared with a normally developing 4-year-old boy, the deceased showed cerebral atrophy and cerebral edema, and Luxol Fast Blue (LFB) stain indicated delayed cerebellar, hippocampal, and basal ganglia development and myelination. A novel frameshift mutation c.584delG in the SLC16A2 gene was detected. Family lineage investigation showed that the mutation was also detected in the deceased's 8-year-old brother and biological mother. The present work enriches the profile mutations in SLC16A2 related to AHDS and emphasizes the importance of autopsy and postmortem genetic analysis in such cases.

Inferior vena cava injury during percutaneous vertebroplasty: a rare cause of fatal pulmonary thromboembolism.

Fatal pulmonary thromboembolism (PTE) following percutaneous vertebroplasty is rare in medical practice. Here, we report the case of a 70-year-old woman who suffered from lumbago with lower extremity pain and lameness and for whom lumbar osteoporotic vertebral compression fractures (L4, L5) were seen on MRI examination. Percutaneous vertebroplasty and posterior vertebral lamina fenestration discectomy were performed. One day later, her condition deteriorated after defecation, and she died suddenly. Pulmonary thromboembolus and deep venous thrombosis in the inferior vena cava were the major findings at forensic autopsy. Due to the rather uncommon components of the thromboembolus (chondrocytes, calcium deposits, and collagen fibers), the pulmonary thromboembolism was attributed to deep venous thrombosis in the inferior vena cava, which was injured during percutaneous vertebroplasty. The present study highlights the conclusion that pulmonary thromboembolism is a rare complication of percutaneous vertebroplasty that should attract the attention of clinical physicians and forensic pathologists.

Forensic identification of a fatal snakebite from Bungarus multicinctus (Chinese krait) by pathological and toxicological findings: a case report.

Bungarus multicinctus (B. multicinctus) is one of the top ten venomous snakes in China, ranking first in lethality at 26.9-33.3%. However, to our knowledge, no forensic autopsy-related cases of death from B. multicinctus bite poisoning have been reported. There are surprisingly few reported cases of death from poisoning by other species of neurotoxic snakes. Neurotoxic snake venom is often highly toxic, and death can quickly occur when bitten in the wild if victims are not taken to a doctor in time. We presented a case of an adult female in Fujian Province of China who was bitten by a poisonous snake while digging for bamboo shoots in the mountains and died from the bite of B. multicinctus confirmed by enzyme-linked immunosorbent assays (ELISA) results. The autopsy's results, histopathological findings, and ELISA results reported here can be helpful for future forensic practice in B. multicinctus venom poisoning; we also briefly review the pathological changes of neurotoxin poisoning, which may be useful in other types of neurotoxin snake venom poisoning.

Forensic Analysis of Sudden Death Associated with Sexual Activity.

OBJECTIVES: To analyze the characteristics of sudden death associated with sexual activity to provide recommendations for forensic identification. METHODS: A retrospective analysis was conducted on autopsy cases accepted by Forensic Identification Center of Huazhong University of Science and Technology from 1998 to 2018, and a total of 15 cases of sudden death associated with sexual activity were screened out. The general information, case data and pathological changes of 15 cases were collected to find the relationship between sexual activity and sudden death. RESULTS: The ratio of male to female was 1.5∶1. The average age of males was 50.1 years and that of females was 35.0 years. Coronary artery diseases and brain diseases accounted for most of the cases (12/15). Sexual partners were associated with locations of deaths and body dumping behaviors. CONCLUSIONS: Sudden death associated with sexual activity, although rare, may occur in people over 30 years old with pre-existing heart or brain diseases, which should be paid attention to in forensic practice.

A novel splicing mutation in Marfan syndrome.

BACKGROUND: Marfan syndrome (MFS) is a connective tissue disease involving multiple organs and systems such as cardiovascular, skeletal, and ocular systems and is also an autosomal dominant inheritance disorder. METHOD: A 30-year-old woman was rushed into the hospital owing to sudden persistent pain in the abdomen and died suddenly 2 days later. To find the real cause of death, a forensic autopsy was conducted owing to suspected medical malpractice, and the diagnosis of MFS was made in accordance with the 2010 revised Ghent nosology. By sequencing the gene of Marfan, aneurysm, and related disorders, a novel splicing mutation in the fibrillin-1 gene (FBN1) was detected. For the clinical characteristic findings (wrist and thumb sign) of the daughter, we recommend genetic analysis for the family. To better understand the role of the variant in the disease, we also investigated functional validation of this mutation. RESULTS: According to the autopsy findings, the cause of death was acute cardiac tamponade caused by aortic rupture. DNA sequencing revealed a novel splicing mutation, c.5672-2delA, which was also detected in her daughter (II2). The functional validation of this mutation showed the base deletion at the same site in the PCR products using cDNA as a template. It is suggested that this mutation may cause abnormal spliceosome during transcription and may encode abnormal protein. CONCLUSION: A novel pathogenic splicing mutation (c.5672-2delA) was confirmed. Present work enriches the profile mutations in FBN1 associated with MFS and stresses the importance of postmortem genetic analysis in such cases.

Niemann-Pick Disease Type B in Traumatic Splenic Rupture.

The rupture of spleen is common in clinical and forensic practice. Trauma is the most common cause of splenic rupture. Although rare, traumatic splenic rupture may occur in these individuals with asymptomatic underlying disease, and clinical and forensic pathologists may neglect the disease and diagnose only the traumatic splenic rupture. Here, we present a case of postinjury splenic rupture resulting in splenectomy, where the patient was diagnosed with Niemann-Pick disease type B through histopathological examination and genetic testing. In forensic practice, in cases of isolation splenic rupture, full microscopy should be done to differentiate traumatic rupture from a spontaneous bleed due to an underlying disease process.

Sudden death associated with delayed cardiac rupture: case report and literature review.

Cardiac injury plays a critical role in the process of thoracic trauma-related fatal outcomes. Historically, most patients who suffer a cardiac rupture typically die at the scene of occurrence or in the hospital, despite prompt medical intervention. Delayed cardiac rupture, although rare, may occur days after the initial injury and cause sudden unexpected death. Herein, we present the clinical details of a young man who suffered a chest stab injury and recovered well initially, but died days later due to delayed cardiac rupture. The forensic autopsy confirmed delayed cardiac rupture as the cause of death. We also reviewed previous similar reports to provide suggestions in such rare cases in clinical and forensic practice.

Molecular biomarkers of diffuse axonal injury: recent advances and future perspectives.

INTRODUCTION: Diffuse axonal injury (DAI), with high mortality and morbidity both in children and adults, is one of the most severe pathological consequences of traumatic brain injury. Currently, clinical diagnosis, disease assessment, disability identification, and postmortem diagnosis of DAI is mainly limited by the absent of specific molecular biomarkers. AREAS COVERED: In this review, we first introduce the pathophysiology of DAI, summarized the reported biomarkers in previous animal and human studies, and then the molecular biomarkers such as ß-Amyloid precursor protein, neurofilaments, S-100ß, myelin basic protein, tau protein, neuron-specific enolase, Peripherin and Hemopexin for DAI diagnosis is summarized. Finally, we put forward valuable views on the future research direction of diagnostic biomarkers of DAI. EXPERT OPINION: In recent years, the advanced technology has ultimately changed the research of DAI, and the numbers of potential molecular biomarkers was introduced in related studies. We summarized the latest updated information in such studies to provide references for future research and explore the potential pathophysiological mechanism on diffuse axonal injury.

Investigation of biodistribution by liquid-phase microextraction: Using a fatal diphenidol poisoning case.

Liquid-phase microextraction (LPME) possesses a high potential to isolate organic substances from different sample matrices. In this work, LPME was applied for the first time to investigate the biodistribution of diphenidol in different biofluids, organs, and brain regions using a fatal poisoning case. Since the LPME of diphenidol hasn't been reported, the effect of supported liquid membrane (SLM), acceptor and donor phases, and extraction time on LPME performance was investigated first. The solvents of 2-nonanone and 2-nitrophenyl octyl ether (NPOE) were found to be stable and efficient SLMs for LPME of diphenidol from biofluids and tissue samples, respectively. At steady state, the LPME recoveries for different sample matrices were in the range of 87 %-91 %. Due to the clean-up capability of LPME and the relatively high concentration of diphenidol in the fatal poisoning case, the proposed LPME systems were validated with related sample matrices using HPLC-UV for the determination. The methods displayed good linearity (R² ≥ 0.9943), and the limits of detection were 0.30 mg L-1, 0.28 mg L-1, and 2.7 µg g-1 for blood, urine, and liver samples, respectively. Meanwhile, the precision (≤13%), accuracy (90-110%), and matrices effect (±15%) were satisfactory at low, medium, and high concentrations. In addition, the stability, carryover, and dilution integrity met the requirements of ASB Standard 036. Finally, the proposed method was successfully applied to evaluate the biodistribution of diphenidol in five different biofluids, five organs, and six brain regions from a fatal poisoning case. Generally, the distribution of diphenidol in biofluids was lower than that in the organs and brain regions, and the highest concentration of diphenidol was observed in the liver, which is very important for the selection of inspection samples in forensic toxicological analysis. Therefore, LPME was proved to be a powerful tool for the investigation of biodistribution and postmortem redistribution in the fields of forensics.

A retrospective study of 29 fatal cases of insulin overdose.

PURPOSE: To summarize recent cases of fatal insulin poisoning both domestically and internationally, thereby offering valuable insights for the forensic identification of insulin overdose cases. METHODS: Literature published since 2000 on fatal insulin overdose were systematically searched and screened. Data encompassing variables such as year, age, sex, cause of death, scene conditions, occupations, medical histories of victims and perpetrators, autopsy timing, dosage and administration methods, forensic pathology, and toxicological analysis, were compiled for rigorous statistical analysis. RESULTS: Among the 29 fatal cases of insulin poisoning, suicides and homicides accounted for 55.2 % and 41.4 %, respectively. Precisely 34.5 % of victims or perpetrators were associated with the medical industry, 27.6 % had diabetes, and 24.1 % had mental illnesses such as depression. Intravenous injection resulted in quicker death than did subcutaneous injection. In some cases, immunohistochemical staining of insulin and protamine at injection sites yielded positive results. The average molar ratio of insulin to C-peptide in post-mortem blood was 13.76 ± 5.167, indicating a significant diagnostic value for insulin poisoning. CONCLUSION: Assessment of cases of fatal insulin overdose should be thorough, incorporating case investigation, scene examination, medical records review, autopsy findings, pathological examinations, and laboratory tests, alongside considering the condition of the body and timing of death autopsy. Using mass spectrometry to detect insulin proves valuable, particularly in cases of poor body preservation.

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.

Xylazine Poisoning in Clinical and Forensic Practice: Analysis Method, Characteristics, Mechanism and Future Challenges.

Xylazine abuse is emerging globally, while the identification of xylazine lethal cases poses a great challenge in clinical and forensic practice. The non-specific symptoms delay the diagnosis and treatment of xylazine poisoning, the pathological changes and lethal concentration of xylazine in body fluid and organs of fatal xylazine poisoning cases are seldom reported and the other toxins detected in such cases complicate the role of xylazine in the cause of death. Therefore, we carefully reviewed related updated information on xylazine, summarized the knowledge from clinical and forensic perspectives and can thus provide a reference in such cases and throw light on further study in the field of xylazine poisoning.

Homicidal paraquat poisoning: Poisoned while drinking.

The incidence of paraquat poisoning has significantly decreased with the addition of odorizer and emetics to the liquid concentrate. Paraquat poisonings are usually attributed to suicidal and accidental or occupational exposure. Here, we report an unusual fatal case of homicidal paraquat poisoning. An intoxicated, a 37-year-old man consumed a mixture of white wine and paraquat prepared by his wife. This resulted in intermittent vomiting, which he attributed to being intoxicated. The man was admitted to the hospital for treatment 3 days later. Due to the lack of knowledge of paraquat exposure, the man did not receive effective treatment and died of respiratory failure 22 days later. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was applied to detect paraquat in 16 postmortem specimens: kidney (1.31 ug/g), urine (0.91 ug/ml), liver (0.62 ug/g), lung (0.39 ug/g), muscle (0.35 ug/g), bile (0.32 ug/ml), heart (0.28 ug/g), brain (0.22 ug/g), pancreas (0.22 ug/g), spleen (0.18 ug/g), cardiac blood (0.15 ug/ml), cerebrospinal fluid (0.14 ug/ml), pericardial effusion (0.12 ug/ml), pleural effusion (0.09 ug/ml), peripheral blood (0.08 ug/ml), and vitreous humor (0.06 ug/ml). The highest concentration of paraquat was detected in the kidney followed by the urine in all tissues and body fluids. At present, although the cases of paraquat poisoning have decreased, the high mortality rate resulting from its irreversible lung damage and respiratory failure makes paraquat poisoning, especially occult paraquat poisoning, still needs to be carefully identified in forensic practice and clinical diagnosis.