The Progression of Postmortem Biochemistry Analysis in Forensic Discrimination of Cause of Death / 中山大学学报(医学科学版)

The discrimination of the cause of death is an important part in forensic medicine. With the advantages of simple operation， high test efficiency， and easy sensitivity to the death mechanism of the deceased， postmortem biochemistry analysis has become a significant auxiliary analysis method for discrimination of the cause of death. In this paper， we discuss the development status， advantages and current problems of postmortem biochemical analysis， and then describe the application prospect of postmortem biochemistry in the discrimination of the cause of death by posing feasible solutions， so that to provide an idea for this research.

Effect of thiamethoxam (organophosphate) on the flies and beetle visitation and cadaveric decomposition process

ABSTRACT Entomofauna associated with decaying cadavers may be useful in criminal investigation, either through the development of immature insects of interest or through entomological succession in corpses. These factors may vary if the insects are exposed to toxic substances that can modify the insect's developmental cycle, as well as its own occurrence, which would imply significant changes in the results of any investigation. However, there are few studies on how contamination by toxic compounds can affect the action of insects on carcasses and their consequence for forensic expertise. Therefore, this study aimed to test the hypothesis that the normal visitation of flies and beetles is altered in insecticide-contaminated carcasses. The experiment was carried out in a sugarcane plantation, using pig carcasses contaminated with insecticide and the same number of carcasses without any type of contamination as a control. In all experiments, the contaminated carcasses reached the final phase of decomposition in a longer time than the uncontaminated carcasses of the control group. A total of 2.767 specimens were collected and identified, 2.103 individuals from the order Diptera and 664 from the order Coleoptera. There was a significant geometric regression adjustment during the decomposition phases only for the control group, different from the contaminated carcasses in which this pattern did not occur. Results show that contamination by insecticide alters decomposition time and phase, altering the action of flies and beetles, affecting the abundance, composition of species as well as their activities, which can alter the data used by experts in criminal experts.

Mapping of SARS-CoV-2 in Waldeyer's lymphatic ring and visceral biopsies: the age and the illness duration's impact

Abstract Objective: To study the impact of age and the interval between disease diagnosis and death on the organotropism of SARS-CoV-2. Method: Patients underwent post-mortem biopsies from lungs, Waldeyer ring, heart, liver, kidneys and bone marrow between 2020-2021. SARS-CoV-2 organotropism was mapped by using molecular RT-PCR analyses for SARS-CoV2 targeting the Envelope gene (E), the RNA Polymerase Gene (RdRp), and the Nucleocapsid gene (N). Statistical and linear regression analysis was performed to study the impact of age and illness duration in SARS-CoV-2 organotropism. Results: We performed 158 postmortem biopsies in 21 patients, with a mean age of 76 years old. The mean interval between the diagnosis of the infection to the death was 23 days. The RNA of the SARS-CoV-2 was detected in 100% of lung biopsies, 76%-82% of Waldeyer's ring biopsies, 55% of heart biopsies, 40% of kidney biopsies, 33% of liver and 25% of bone marrow biopsies. Patients who died before the day 9, presented extensive visceral dissemination of SARS-CoV-2 RNA. Most of the patients older than 80 years (90%) presented visceral dissemination of SARS-CoV-2 RNA, while among younger patients, only 3/11 patients presented visceral dissemination of the virus. The relationship between "age" and "illness duration" and multitropism of the virus was statistically significant (p< 0.001). Conclusion: Disease interval and age were factors that were significantly associated with RT-PCR positive results in multiple organs. Critical COVID-19 patients have multiorganic viral dissemination in early stages. In the critical older patients, multiorganic viral dissemination is the rule. Level of evidence: 4. Case Series.

Occupational lung diseases in South African miners at autopsy: 2020 surveillance report

The Pathology Division at the National Institute for Occupational Health (NIOH) provides autopsy services for deceased workers who worked in controlled mines or works under the provisions of the South African Occupational Diseases in Mines and Works Act, 1973 (Act No. 78 of 1973). This report describes the ages, commodities, employment durations, and occupational cardio-respiratory diseases in miners whose organs were submitted for autopsies in 2019 and 2020. Data were exported from the PATHAUT database into STATA for analysis. Differences in the proportions of disease (expressed per 1 000) were calculated using the Pearson's chi-square test; significance was set at p ≤ 0.05. There were 759 and 557 records of deceased miners and ex-miners in 2019 and 2020, respectively. Pulmonary tuberculosis decreased from 192/1 000 in 2019 to 153/1 000 autopsies in 2020, and silicosis decreased from 246/1 000 to 223/1 000. However, neither decrease was significant. There was a significant increase in the rate of asbestosis from 50/1 000 in 2019 to 79/1 000 in 2020. Pulmonary tuberculosis (TB), emphysema, and silicosis were the most frequent diseases, with high rates. There was a non-significant decrease in occupational respiratory disease rates in 2020 from 2019, but these remain higher than the rates seen in the early 1990s. The NIOH continues to conduct autopsy surveillance on miners to support compensation for families, and the development of policy and intervention programmes in the mining industry

Postmortem Interval Estimation Using Protein Chip Technology Combined with Multivariate Analysis Methods / 法医学杂志

OBJECTIVES@#To estimate postmortem interval (PMI) by analyzing the protein changes in skeletal muscle tissues with the protein chip technology combined with multivariate analysis methods.@*METHODS@#Rats were sacrificed for cervical dislocation and placed at 16 ℃. Water-soluble proteins in skeletal muscles were extracted at 10 time points (0 d, 1 d, 2 d, 3 d, 4 d, 5 d, 6 d, 7 d, 8 d and 9 d) after death. Protein expression profile data with relative molecular mass of 14 000-230 000 were obtained. Principal component analysis (PCA) and orthogonal partial least squares (OPLS) were used for data analysis. Fisher discriminant model and back propagation (BP) neural network model were constructed to classify and preliminarily estimate the PMI. In addition, the protein expression profiles data of human skeletal muscles at different time points after death were collected, and the relationship between them and PMI was analyzed by heat map and cluster analysis.@*RESULTS@#The protein peak of rat skeletal muscle changed with PMI. The result of PCA combined with OPLS discriminant analysis showed statistical significance in groups with different time points (P<0.05) except 6 d, 7 d and 8 d after death. By Fisher discriminant analysis, the accuracy of internal cross-validation was 71.4% and the accuracy of external validation was 66.7%. The BP neural network model classification and preliminary estimation results showed the accuracy of internal cross-validation was 98.2%, and the accuracy of external validation was 95.8%. There was a significant difference in protein expression between 4 d and 25 h after death by the cluster analysis of the human skeletal muscle samples.@*CONCLUSIONS@#The protein chip technology can quickly, accurately and repeatedly obtain water-soluble protein expression profiles in rats' and human skeletal muscles with the relative molecular mass of 14 000-230 000 at different time points postmortem. The establishment of multiple PMI estimation models based on multivariate analysis can provide a new idea and method for PMI estimation.

Research Progress on Estimation of Postmortem Interval Based on Ocular Tissues Structure / 法医学杂志

Estimation of postmortem interval (PMI) is one of the important research contents in forensic pathology, and it has always been the focus and hot spot of research work. In recent years, scholars at home and abroad have made some research progress in estimating PMI by using ocular tissue. After death, the changes of cornea, aqueous humor, iris, lens, vitreous humor and retina all show time sequence change rule highly related to PMI. This paper reviews the research progress of PMI estimation based on the morphological, biochemical, molecular and genetic material changes of different ocular tissue structures after death, and discusses the existing problems and development trends.

Comparison of CT Values between Thrombus and Postmortem Clot Based on Cadaveric Pulmonary Angiography / 法医学杂志

OBJECTIVES@#To explore the difference in CT values between pulmonary thromboembolism and postmortem clot in postmortem CT pulmonary angiography (CTPA) to further improve the application value of virtual autopsy.@*METHODS@#Postmortem CTPA data with the definite cause of death from 2016 to 2019 were collected and divided into pulmonary thromboembolism group (n=4), postmortem clot group (n=5), and control group (n=5). CT values of pulmonary trunk and left and right pulmonary artery contents in each group were measured and analyzed statistically.@*RESULTS@#The average CT value in the pulmonary thromboembolism group and postmortem clot group were (168.4±53.8) Hu and (282.7±78.0) Hu, respectively, which were lower than those of the control group (1 193.0±82.9) Hu (P<0.05). The average CT value of the postmortem clot group was higher than that of the pulmonary thromboembolism group (P<0.05).@*CONCLUSIONS@#CT value is reliable and feasible as a relatively objective quantitative index to distinguish pulmonary thromboembolism and postmortem clot in postmortem CTPA. At the same time, it can provide a scientific basis to a certain extent for ruling out pulmonary thromboembolism deaths.

Pathological Changes and Cause of Death Associated with the Global Novel Coronavirus Disease (COVID-19) / 法医学杂志

The coronavirus disease 2019 (COVID-19) has been a global epidemic for more than three years, causing more than 6.9 million deaths. COVID-19 has the clinical characteristics of strong infectivity and long incubation period, and can cause multi-system damage, mainly lung damage, clinical symptoms of acute respiratory distress syndrome (ARDS) and systemic multiple organ damage. The SARS-CoV-2 virus is still constantly mutating. At present, there is no global consensus on the pathological changes of COVID-19 associated deaths and even no consensus on the criteria for determining the cause of death. The investigation of the basic pathological changes and progression of the disease is helpful to guide the clinical treatment and the development of therapeutic drugs. This paper reviews the autopsy reports and related literature published worldwide from February 2020 to June 2023, with a clear number of autopsy cases and corresponding pathological changes of vital organs as the inclusion criteria. A total of 1 111 autopsy cases from 65 papers in 18 countries are included. Pathological manifestations and causes of death are classified and statistically analyzed, common pathological changes of COVID-19 are summarized, and analytical conclusions are drawn, suggesting that COVID-19 infection can cause life-threatening pathological changes in vital organs. On the basis of different health levels of infected groups, the direct cause of death is mainly severe lung damage and secondary systemic multiple organ failure.

Application of Targeted Coronary Angiography in the Diagnosis of Sudden Cardiac Death / 法医学杂志

OBJECTIVES@#To diagnose coronary artery stenosis by using the postmortem computed tomography angiography (PMCTA), and to explore the diagnostic value of PMCTA in sudden cardiac death.@*METHODS@#Six death cases were selected, and the contrast medium iohexol was injected under high pressure through femoral artery approach with 5F pigtail catheter to obtain coronary image data and then the data was analyzed. The results of targeted coronary imaging and coronary artery calcium score (CaS) were compared with the results of conventional autopsy and histopathological examination.@*RESULTS@#The autopsy and histopathological examination of cases with coronary artery stenosis obtained similar results in targeted coronary angiography, with a diagnostic concordance rate of 83.3%. Targeted coronary angiography could effectively show coronary artery diseases, and the CaS was consistent with the results of conventional autopsy and histopathological examination.@*CONCLUSIONS@#Targeted coronary angiography can be used as an effective auxiliary method for conventional autopsy in cases of sudden cardiac death.

Research Progress on Microbial Community Succession in the Postmortem Interval Estimation / 法医学杂志

The postmortem interval (PMI) estimation is a key and difficult point in the practice of forensic medicine, and forensic scientists at home and abroad have been searching for objective, quantifiable and accurate methods of PMI estimation. With the development and combination of high-throughput sequencing technology and artificial intelligence technology, the establishment of PMI model based on the succession of the microbial community on corpses has become a research focus in the field of forensic medicine. This paper reviews the technical methods, research applications and influencing factors of microbial community in PMI estimation explored by using high-throughput sequencing technology, to provide a reference for the related research on the use of microbial community to estimate PMI.

Retrospective Analysis of Death Cases of Oral Diphenidol Hydrochloride Poisoning / 法医学杂志

OBJECTIVES@#To explore the characteristics of postmortem examination, chemical examination and scene investigation of deaths caused by oral diphenidol hydrochloride poisoning, and so as to provide a reference for proper settlement and prevention of such deaths.@*METHODS@#The data of 22 deaths caused by oral diphenidol hydrochloride poisoning in a city from January 2018 to August 2020 were collected, including case details, scene investigations, autopsies, chemical examinations and digital evidence. Thirty-one cases of deaths caused by oral diphenidol hydrochloride poisoning reported in previous literature were also collected.@*RESULTS@#In the 53 oral diphenidol hydrochloride poisoning death cases, 50 cases were suicide, 2 cases were accidental, while 1 case was undetermined. Fifty-two cases were found in the medical records or crime scene investigation reports with doses ranging from 775 mg to 12 500 mg, and 23 deceased were detected with postmortem blood concentrations ranging from 2.71 mg/L to 83.1 mg/L. Clinical symptoms were recorded in 6 patients, including conscious disturbance and convulsion. Among the 45 cases which were performed with external examination, 23 cases autopsied.@*CONCLUSIONS@#Most of the deceased of oral diphenidol hydrochloride poisoning were suicide. No significant correlation was found between dose and blood concentration through the retrospective analysis of cases.

Post-mortem pulmonary tuberculosis: comparison of available diagnostic methods

@#Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a serious public health threat with the World Health Organisation (WHO) reporting 5.8 million cases and 1.3 million deaths in the year 2020 due to TB. TB can be diagnosed by imaging, histopathological and bacteriological methods with culture remaining the gold standard. This study was performed to look at the sensitivity and specificity of post-mortem computed tomography (PMCT) imaging when compared to culture in diagnosing pulmonary tuberculosis. This was a retrospective comparative study looking at post mortem cases where lung tissue samples sent for TB culture at Hospital Kuala Lumpur were compared against PMCT imaging. Exclusion criteria included contaminated samples, decomposed cases, immunocompromised subjects and those below 18 years of age. Subjects included 80 medico-legal autopsy cases at the National Institute of Forensic Medicine, Hospital Kuala Lumpur, Malaysia who had whole body PMCT done in accordance with the Institute’s protocol and tissue samples sent for bacteriology culture for tuberculosis. PMCT findings were positively associated with acid-fast organisms in 23.5 out of 33 cases (71.2%). Our study also showed that PMCT had a sensitivity of 71.3% and specificity of 54.3% (95% CI: 39.5–68.4) in diagnosing TB based on the protocol set in this study. This study showed that there was relatively good agreement between radiological PMCT findings and bacterial culture, suggesting that radiological examination is a relatively reliable tool for preliminary screening and possible diagnosis of TB prior to a postmortem examination which would be beneficial in reducing the risk of transmission of TB to health workers during autopsy.

Tributo a la vida y obra de Juan Eloy Valenzuela y Mantilla, el primer médico de Bucaramanga

En este escrito se hace breve mención a la Real Expedición Botánica de la Nueva Granada como escuela de botánica de Eloy Valenzuela, a su mentor, el protomédico gaditano José Celestino Mutis, al protagonismo de Valenzuela en los aspectos sociales de los pobladores de la Villa de Bucaramanga en el siglo XVIII. También se muestran las enfermedades más frecuentes de la época y los remedios con que eran socorridos los pacientes.

This paper does a brief mention of the Royal Botanical Expedition of New Granada as Eloy Valenzuela's school of botany. Shows José Celestino Mutis, the Spanish protomedical mentor of Valenzuela, and describes the Valenzuela's leading role in the social aspects of the inhabitants of the Villa de Bucaramanga in the 18th century. The most frequent diseases of the time and the remedies with which patients were helped are shown.

Assessment of Post-mortem Processing Methods on Quality and Shelf Life of Mutton

This study was carried out to assess the influence of post-mortem processing methods on quality and shelf life of two breeds of sheep meat. A total of twelve sheep, six each from Balami and Ouda (two prominent breed of Sheep in Nigeria) were weighed, slaughtered and allotted to three processing methods which are scalding, singeing and skinning in a completely randomized experimental design in a 2 × 3 factorial arrangement (2 breeds and 3 post-mortem processing methods). The carcass characteristics, primal cuts, physico-chemical properties, sensory and microbial counts were assessed. The results showed that Ouda breed gave the highest (p<0.05) dressing % (36.43%), preferred (p<0.05) primal cuts in rounds (15.13%), Marbling score, lipid profile (Total cholesterol, LDL), and Lipid peroxidation, Balami sheep was however rated higher (p<0.05) in juiciness, tenderness and overall acceptability. The Scalded sheep had the highest dressing % (35.45%), with preferred marbling score (5.80), and microbial counts. The scalded samples were also the lowest (p<0.05) for crude Fiber, CF, total cholesterol (276.40 mg/dL) and LDL (183.89 mg/dL). Minimal exudate loses (cooking loss and drip loss) were recorded in singeing samples and was rated highest (p<0.05) with organoleptic properties. The microbial and fungi loads increased with the storage days. Conclusively, Ouda breed and Scalding method of post-mortem dressing gave the preferred values for optimum nutrients and shelf-life of sheep meat.

Presence of Helicobacter spp. in dental tartar and gastric mucosa, and its relationship with EGUS in horses from a public slaughterhouse

Background: Despite the fact that Helicobacter spp. has been detected in equine gastric mucosa, no evidence exists about this infection in Colombian horses affected by equine ulcerative gastric syndrome (EGUS), nor in dental tartar. Objective: To detect Helicobacter spp. DNA in equine gastric mucosa and dental tartar and determine the relationship between the presence of Helicobacter spp. and gastric lesions. Methods: Samples of glandular gastric mucosa and dental tartar were collected from 30 equine slaughterhouses. Macroscopic lesions of the stomachs were classified and the total DNA in all samples was extracted using a commercial extraction kit. A final-point PCR was performed using primers for amplification of a segment of 251 bp of the gene encoding the 16s rRNA region; the amplified fragments were subjected to a second PCR to determine the presence of H. pylori, the VacA gene was typified. The resulting amplicons were sequenced. Results: It was possible to amplify 16s rRNA in several samples but there was no amplification of VacA. Fragments of the sequences were compatible with H. heilmannii. The 23.3 and 10% of gastric and tartar samples were positive for 16s rRNA of Helicobacter spp., respectively. Conclusion: Although genetic material of Helicobacter spp. was found in some animals, there was no relationship with gastric lesions. It is possible that helicobacteriosis has no bearing in EGUS etiology.

Antecedentes: A pesar de que se ha detectado Helicobacter spp. en mucosa gástrica equina, no existe evidencia de esta infección en caballos criollos colombianos afectados por síndrome ulcerativo gástrico (SUGE), ni tampoco reportes en sarro dental. Objetivo: Detectar ADN de Helicobacter spp. en sarro dental y mucosa gástrica de equinos, y determinar la relación entre la presencia de la bacteria y lesiones gástricas. Métodos: Las muestras de mucosa glandular gástrica y sarro dental fueron colectadas de 30 equinos que se encontraban en planta de beneficio. Las lesiones macroscópicas fueron clasificadas y el ADN total de las muestras fue extraído utilizando un kit comercial. Se desarrolló PCR convencional usando cebadores específicos para la amplificación de un segmento de 251 pb de un gen que codifica la región 16S del ARNr; los fragmentos amplificados fueron sometidos a una segunda PCR para determinar la presencia de H. pylori mediante la amplificación del gen VacA. Los amplificados resultantes fueron secuenciados. Resultados: Fue posible amplificar 16s ARNr en varias muestras, pero no hubo amplificación de VacA. Los fragmentos de las secuencias fueron compatibles con H. heilmannii. El 23,3 y 10% de las muestras gástricas y sarro fueron positivas para 16s ARNr de Helicobacter spp., respectivamente. Conclusión: Aunque el material genético de Helicobacter spp. se encontró en algunos animales, no hubo relación con las lesiones gástricas. Es posible que la helicobacteriosis no tenga incidencia en la etiología del EGUS.

Antecedentes: Apesar do Helicobacter spp. ter sido detectado na mucosa gástrica de equinos, não há evidências dessa infecção em cavalos crioulos colombianos afetados pela síndrome ulcerativa gástrica (SUGE), ou no sarro. Objetivo: Detectar ADN de Helicobacter spp. na mucosa gástrica e do sarro dental de equinos, e determinar a relação entre a presença de Helicobacter spp. e lesões gástricas. Métodos: Amostras de mucosa gástrica glandular e sarro dental foram coletadas de 30 equinos de abatedouro, as lesões macroscópicas dos estômagos foram classificadas. Se realizou extração de ADN total em todas as amostras através de kit comercial. Realizou-se PCR ponto final, amplificando o segmento de 251 pb do gene que codifica para a região 16s ARNr; os fragmentos amplificados foram sometidos novamente a PCR para determinar a presença de H. pylori, ao tipificar o gene VacA, e seguidamente foram sequenciados. Resultados: O houve amplificação do 16s ARNr em várias amostras, mas não amplificação de VacA. Fragmentos das sequencias foram compatíveis com H. heilmannii. O 23,3 e 10% das amostras gástricas e do sarro foram positivas para 16s ARNr de Helicobacter, respectivamente. Conclusão: Embora material genético de Helicobacter spp. encontrou-se em algumos animais não houve relação com lesões gástricas. Possivelmente a helicobacterioses não tem papel relevante na etiologia da SUGE.

Histopathological analysis of residual lens cells in capsular opacities after cataract surgery using objective software

Purpose: Remnant lens epithelial cells (LECs) within the capsular bag (CB) undergo epithelial?to?mesenchymal transition (EMT) and acquire a myofibroblast phenotype, depositing extracellular matrix (ECM) components, leading to posterior capsular opacification (PCO). This study histopathologically analyzes the LEC?to?myofibroblast transition and de novo ECM component deposition (i.e., smooth muscle actin (SMA) and fibronectin (FN) expression) and determines the intraocular lens (IOL) and patient factors associated with these changes. Methods: In total, 190 CBs with IOLs were removed from donor eyes. Digital images were obtained, and PCO was graded using published software (ADOS, Medical Parachute). Automated immunohistochemistry was performed using anti?SMA to detect EMT and anti?FN to document ECM remodeling. Slides were digitized and analyzed using the Positive Pixel Count v9 algorithm. Linear regression and Poisson regression were performed (P < 0.05). Results: SMA positive expression decreased as the time of IOL implantation increased (P < 0.0001). Positivity of SMA and FN demonstrated a positive correlation (P = 0.0002). Controlling for confounding factors in Poisson regression, hydrophobic and hydrophilic materials showed higher FN and SMA expression when compared to silicone material lenses (FN; P = 0.018; P < 0.0001, SMA; P = 0.001; P = 0.003, respectively). The square optic design had 29% higher SMA positivity compared to the opti?edge design (P = 0.042). One?piece haptic lenses had higher SMA expression compared to three?piece haptic (P = 0.042). A higher risk of expression of SMA and FN was seen in patients with a history of smoking, hypertension, and glaucoma (P < 0.05). Conclusion: This study demonstrated that SMA and FN expression is different according to IOL design and patient factors, thus indicating that LEC changes depend on lens biocompatibility. Therefore, by analyzing the histopathological composition of PCO by using LECs, further insight into the characteristics of IOLs that are important for biocompatibility can be ascertained.

Consentimiento informado en la toma de muestras postmortem: revisión bibliográfica / Informed consent of postmortem sampling: Bibliographic review

Justificación: el consentimiento informado, se fundamenta en el principio de autonomía de las personas, la concepción moral sobre el respeto de la dignidad del ser humano y por tanto en su libertad. En el consentimiento informado se articulan el resto de los principios bioéticos universales: la no maleficencia, la justicia, y la beneficencia. Objetivo: Establecer las situaciones en las cuales es pertinente aplicar el consentimiento informado en la toma de muestras postmortem desde un enfoque bioético versus un enfoque legal. Metodología: se realizó una revisión en: Scielo, LILACS, IBECS, CUMED, NIH, Repositorio de la Organización Panamericana de la Salud; usando palabras clave: consentimiento informado, derechos humanos, autonomía, bioética, autopsia, muestras postmortem y médicos forenses y combinaciones de estas. Los criterios de inclusión: artículos con antigüedad máxima de cinco años, en español e inglés de libre acceso. Resultados: se obtuvieron 113 artículos utilizando las palabras clave y sus combinaciones, más otros 43 registros adicionales identificados de otras fuentes como leyes, reglamentos etc. Al eliminar las fuentes: duplicadas, no relevantes, inhabilitadas e incompletas se trabajó con un total de 49 artículos. Conclusiones: existe la necesidad de incluir en las pautas éticas nacionales e internacionales que regulan la investigación científica, lineamientos a seguir sobre la realización del proceso del consentimiento informado en los estudios que involucren muestras postmortem, utilizadas posteriormente a su uso primario...(AU)

Practical tips to using formalin-fixed paraffin-embedded tissue archives for molecular diagnostics in a South African setting

Background: Formalin-fixed paraffin-embedded (FFPE) tissue archives in hospitals, biobanks, and others offer a vast collection of extensive, readily available specimens for molecular testing. Unfortunately, the use of tissue samples for molecular diagnostic applications is challenging; thus, the forensic pathology FFPE tissue archives in Africa have been a largely unexploited genetic resource, with the usability of DNA obtainable from these samples being unknown.Intervention: The study, conducted from January 2015 to August 2016, determined the usefulness of FFPE tissue as a reliable source of genetic material for successful post-mortem molecular applications and diagnostics. Formalin-fixed paraffin-embedded tissue samples were collected and archived from autopsies conducted over 13 years in the forensic medicine department of the University of Pretoria (Pretoria, South Africa). Deoxyribonucleic acid from FFPE tissue samples and control blood samples was amplified by high-resolution melt real-time polymerase chain reaction before sequencing. The procurement parameters and fixation times were compared with the quantity and quality of the extracted DNA and the efficiency of its subsequent molecular applications.Lessons learnt: This study has shown that FFPE samples are still usable in molecular forensics, despite inadequate sample preparation, and offer immense value to forensic molecular diagnostics.Recommendations: FFPE samples fixed in formalin for more than 24 h should still be used in molecular diagnostics or research, as long as the primer design targets amplicons not exceeding 300 base pairs.

Causes of death and post-mortem testing for SARS-CoV-2 in a tertiary hospital during the COVID-19 pandemic in Ghana

Background: Causes of death during the coronavirus disease 2019 (COVID-19) pandemic ranhttp://crossmark.crossref.org/dialog/?doi=10.4102/ajlm.v11i1.1766=pdf&date_stamp=2022-11-23ge from direct consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection to deaths unrelated to SARS-CoV-2. Another feature of the pandemic is the post-mortem testing for SARS-CoV-2. Understanding these aspects of COVID-19 are essential in planning and limiting the impact of SARS-CoV-2 virus on healthcare systems. Objective: This study investigated the underlying causes of death and the presence of SARS-CoV-2 in bodies received at the 37 Military Hospital, Accra, Ghana, during the COVID-19 pandemic. Methods: The study was conducted from 4­27 May 2020. Deceased patients that met the inclusion criteria were prospectively selected during the expanded surveillance period for SARS-CoV-2 testing, autopsy and determination of underlying and immediate cause of death. Results: A total of 161 deceased patients were analysed with 53 autopsies. The overall positive test rate for SARS-CoV-2 was 14.9% (24/161 patients), with a positive rate of 5.0% (8/161 patients) for nasopharyngeal samples and 30.2% (16/161 patients) for bronchopulmonary samples. The underlying causes of death were not related to SARS-CoV-2 infection in 85.1% (137/161) of patients, SARS-CoV-2-associated 12.4% (20/161) and SARS-CoV-2-induced in 2.5% (4/161). Cardiovascular complications formed the most common cause of death in patients with or without SARS-CoV-2. Conclusion: There was a high positive rate of SARS-CoV-2 in post-mortem cases. However, most deaths were not caused by SARS-CoV-2 but by cardiovascular complications. The high rate of bronchopulmonary positive results for SARS-CoV-2 requires that autopsies be done in suspicious cases with negative nasopharyngeal sampling.

Research Progress of Exosomes and Their Forensic Significance / 法医学杂志

Exosomes are membranous tiny vesicles secreted by cells, which are widely found in the extracellular matrix and various body fluids and carry a variety of biologically functional molecules such as proteins, lipids, messenger RNA (mRNA) and microRNA (miRNA). Exosomes not only play important biological roles in the field of immunology and oncology, but also have potential application value in the field of forensic medicine. This article reviews the discovery, production and degeneration mechanism, biological functions, isolation and identification methods of exosomes, summarizes the research on exosomes and their significance in the field of forensic science, and discusses their applications in body fluid identification, individual identification, postmortem interval estimation to provide ideas for the application of exosomes in forensic work.