Inferring Postmortem Submersion Interval in Rats Found in Water Based on Vitreous Humor Metabolites / 法医学杂志

OBJECTIVES@#The metabolomics technique of LC-MS/MS combined with data analysis was used to detect changes and differences in metabolic profiles in the vitreous humor of early rat carcasses found in water, and to explore the feasibility of its use for early postmortem submersion interval (PMSI) estimation and the cause of death determination.@*METHODS@#The experimental model was established in natural lake water with 100 SD rats were randomly divided into a drowning group (n=50) and a postmortem (CO2 suffocation) immediately submersion group (n=50). Vitreous humor was extracted from 10 rats in each group at 0, 6, 12, 18 and 24 h postmortem for metabolomics analyses, of which 8 were used as the training set to build the model, and 2 were used as test set. PCA and PLS multivariate statistical analysis were performed to explore the differences in metabolic profiles among PMSI and causes of death in the training set samples. Then random forest (RF) algorithm was used to screen several biomarkers to establish a model.@*RESULTS@#PCA and PLS analysis showed that the metabolic profiles had time regularity, but no differences were found among different causes of death. Thirteen small molecule biomarkers with good temporal correlation were selected by RF algorithm. A simple PMSI estimation model was constructed based on this indicator set, and the data of the test samples showed the mean absolute error (MAE) of the model was 0.847 h.@*CONCLUSIONS@#The 13 metabolic markers screened in the vitreous humor of rat corpses in water had good correlations with the early PMSI. The simplified PMSI estimation model constructed by RF can be used to estimate the PMSI. Additionally, the metabolic profiles of vitreous humor cannot be used for early identification of cause of death in water carcasses.

Genomic Epidemiology of Imported Cases of COVID-19 in Guangdong Province, China, October 2020 - May 2021 / 生物医学与环境科学（英文）

Objective@#The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been engendering enormous hazards to the world. We obtained the complete genome sequences of SARS-CoV-2 from imported cases admitted to the Guangzhou Eighth People's Hospital, which was appointed by the Guangdong provincial government to treat coronavirus disease 2019 (COVID-19). The SARS-CoV-2 diversity was analyzed, and the mutation characteristics, time, and regional trend of variant emergence were evaluated.@*Methods@#In total, 177 throat swab samples were obtained from COVID-19 patients (from October 2020 to May 2021). High-throughput sequencing technology was used to detect the viral sequences of patients infected with SARS-CoV-2. Phylogenetic and molecular evolutionary analyses were used to evaluate the mutation characteristics and the time and regional trends of variants.@*Results@#We observed that the imported cases mainly occurred after January 2021, peaking in May 2021, with the highest proportion observed from cases originating from the United States. The main lineages were found in Europe, Africa, and North America, and B.1.1.7 and B.1.351 were the two major sublineages. Sublineage B.1.618 was the Asian lineage (Indian) found in this study, and B.1.1.228 was not included in the lineage list of the Pangolin web. A reasonably high homology was observed among all samples. The total frequency of mutations showed that the open reading frame 1a (ORF1a) protein had the highest mutation density at the nucleotide level, and the D614G mutation in the spike protein was the commonest at the amino acid level. Most importantly, we identified some amino acid mutations in positions S, ORF7b, and ORF9b, and they have neither been reported on the Global Initiative of Sharing All Influenza Data nor published in PubMed among all missense mutations.@*Conclusion@#These results suggested the diversity of lineages and sublineages and the high homology at the amino acid level among imported cases infected with SARS-CoV-2 in Guangdong Province, China.

Application Prospect of MicroRNA in Skin Wound Age Estimation / 法医学杂志

Wound age estimation is one of the major tasks in forensic practice. However, relatively accurate estimation of the wound age is still a conundrum and research spotlight world-widely. Studies show that microRNAs (miRNAs) are involved in the whole process of the skin wound repair, and miRNAs, as biomarkers, might be used to estimate the time of skin injury owing to their characteristic advantage. This paper summarizes the miRNA fundamental function, properties, current research progress in the estimation of wound age, and its limitations, and put forward prospect of potential application and research based on miRNAs in estimation of wound age.

Research Progress on Estimation of Postmortem Submersion Interval / 法医学杂志

Postmortem interval （PMI） estimation is one of the most important and difficult academic tasks in forensic sciences. Due to the influence of the corpse itself and the water environment, corpses in water have unique corruption phenomenon and laws. Based on the experience of traditional PMI studies of corpses on land, forensic practitioners across the world have proposed a variety of practical methods for estimating postmortem submersion interval （PMSI）. This paper summarizes the literatures related to PMSI in recent years, and introduces methods to infer PMSI according to the phenomenon of corpses, the development of insects, the succession pattern of aquatic organisms, and the changes of other physical and chemical indexes of corpses, in order to provide some reference for the study of PMSI of corpses in water.

Guide to the Forensic Pathology Practice on Death Cases Related to Corona Virus Disease 2019 （COVID-19） （Trial Draft） / 法医学杂志

Autopsy is of great significance to the elucidation of the pathological changes, pathogeneses and causes of death of corona virus disease 2019 （COVID-19） and can provide theoretical basis for more scientific and accurate prevention and control of the outbreak. Based on related laws and regulations, such as the Law of the People's Republic of China on Prevention and Control of Infectious Diseases, the clinical manifestations and epidemiological characteristics of COVID-19, and the related guidelines on the prevention and control of the outbreak, combined with the practical work of forensic pathology examination, the Guide to the Forensic Pathology Practice on Death Cases Related to Corona Virus Disease 2019 （COVID-19） （Trial Draft） has been developed. This guide includes information on the background investigation of the cases, autopsy room requirements, personal prevention and protections, external examinations, autopsy, auxiliary examinations, and so on. This guide can be used as a reference by forensic and pathological examination institutions, as well as examination staff.

Statistical Analysis of the Heart and Lung Mass in Forensic Anatomical Cases and Its Forensic Significance / 法医学杂志

Objective To investigate the differences of heart mass and lung mass in forensic autopsy cases and to explore their application value in forensic identification. Methods The data from 1 614 autopsy cases accepted by center of Medico-legal Investigation of China Medical University between 2007 to 2016 were collected. The correlation of heart and lung mass with age, height, body weight, and body mass index （BMI）, as well as differences in different causes of death were analyzed by GraphPad Prism 6.0 software. Results The heart mass and lung mass of males were higher than those of females （P<0.05）. The heart mass of males and females was positively correlated with age, height, body weight and body mass index （BMI） （P<0.05）. The heart mass of patients dying from sudden cardiac death （SCD） was significantly higher than those dying from other causes of death. The lung mass of patients dying from drowning and delayed treatment was higher than those dying from other causes of death （P<0.05）. Conclusion In forensic practice, measurement of the heart mass and lung mass has certain significance for differential diagnosis and diagnosis of different causes of death.

Relationship between the Degeneration and Regeneration of Neuromuscular Junction and Wound Age during the Repair of Mouse Skeletal Muscle Contusion / 法医学杂志

Objective To investigate the morphological changes in the degeneration and regeneration of neuromuscular junctions （NMJ） during the repair of mouse skeletal muscle contusion and discuss the correlation between the degeneration and regeneration of NMJ and wound age. Methods A total of 50 healthy adult male mice were randomly divided into 10 groups, including 9 experimental groups and 1 control group. Immunofluorescent staining was applied, and neurofilament was marked with neurofilament protein-H （NF-H）, presynaptic membrane was marked with synaptophysin （Syn）, presynaptic membrane was marked with acetylcholine receptor （AChR）. Morphological changes of NMJ regeneration at different time points after mouse skeletal muscle contusion were detected. Results The neurofilament and presynaptic membrane of NMJ at the junction of contusion zones began to degrade after contusion, and completed degradation at about 3 d post-injury. Then they gradually regenerated, roughly completing the regeneration at about 21 d and basically reaching the control group level. The ratio of presynaptic membrane quantity to presynaptic membrane quantity showed a trend of decreasing then rising and finally reaching the control level. Conclusion During the repair of mouse skeletal muscle contusion, the morphological changes and wound age of the NMJ at the junction of contusion zones have a close correlation, which is expected to be one of the biological indicators for forensic skeletal muscle wound age estimation.

Expression of Nrf2 in Different Cells after Human Cerebral Cortex Contusion / 法医学杂志

Objective To observe the expression changes of nuclear factor-erythroid derived 2-related factors （Nrf2） in different cells at different time points after human cerebral cortex contusion, and to discuss its application in brain wound age estimation. Methods Thirty-six human brain tissues were selected, of which 6 were for control and 30 were cortical contusion at different time points post-injury, which were divided into 0-1 h, 3-6 h, 1-3 d, 5-7 d, and 10-14 d post-injury groups, with 6 cases in each group. Based on paraffin embedded sections, HE staining was used to observe the morphological changes post-injury, and double immunofluorescence staining was used to detect the expression of Nrf2 in neurons, astrocytes, and microglia. The number of positive cells was counted and statistical analysis was made. Results The number of neurons decreased 1-3 d post-injury. The expression of Nrf2 cells in neurons increased after injury, and the rate of positive cells peaked at 1-3 d post-injury. Glial cells were activated 1-3 d post-injury, and the activation peaked at 5-7 d post-injury. The cerebromalacia began to form at 10-14 d post-injury. Glial fibrillary acidic protein （GFAP） positive cells in mice increased gradually after injury and peaked at 5-7 d post-injury, while the proportion of Nrf2 in GFAP positive cells was relatively stable. After injury, ionized calcium-binding adapter molecule 1 （IBA1） positive cells increased and activated gradually. The expression proportion of Nrf2 in IBA1 positive cells increased gradually, reached its peak at 5-7 d post-injury, and then decreased. Conclusion The expression of Nrf2 in different cells involves in the biological function of different cells post-injury, and the dynamic expression of single cells has a time-dependent pattern. This may provide a new reference index for the wound age estimation of brain contusion in human.

Relationship between Changes of Pericyte Number and Wound Age during Repair of Skeletal Muscle Contusion in Mice / 法医学杂志

Objective To observe the change pattern of pericyte number at different time periods after mice skeletal muscle contusion and discuss its role in wound age estimation. Methods A mice gastrocnemius muscle contusion model was established. The form and number changes of pericytes at 1, 3, 5, 7, 9, 14, and 28 d post-injury were detected by multiple immunofluorescence staining. Results Compared with the slender shape of pericytes in normal skeletal muscles, pericytes in the contusion area had increased volume, rounder form and a round nuclei. Part of pericytes were found to express satellite cell markers paired-box transcription factor （Pax7） or myoblast determination 1 （MyoD1）. The changes of pericyte number in skeletal muscles after contusion were time-dependant, and showed unimodal distribution with the extension of wound age. In the central contusion area, the number of pericytes peaked at 5 d post-injury while in the peripheral contusion area, the number of pericytes peaked at 5 d and 7 d post-injury. Conclusion The number of pericytes in contusion area varies time-dependently after skeletal muscle contusion in mice and might be a reference index for muscle wound age estimation, and is involved in the repair and regeneration of skeletal muscle injury.

Research Progress?on?Age?Determination?of?Venous?Thrombosis in Forensic Medicine / 法医学杂志

Pulmonary thromboembolism （PTE）, which is caused by detachment of venous thrombosis, is a common cause of sudden death in forensic practice. In the cases which die of PTE after trauma or die of PTE during non-thrombosis disease hospitalization, forensic pathologists are required to analyze the time sequence between trauma or medical practice and venous thrombosis, and then analyze their causal relationship. This review summarizes the history of thrombus age estimation and recent advances in forensic medicine, and then gives a brief outlook for future research to provide reference for forensic identification of PTE and guide follow-up studies.

Relationship between Expression Changes of CB2R and Wound Age of Brain Contusion in Mice / 法医学杂志

Objective To investigate the expression of cannabinoid type 2 receptor （CB2R） at different time points after brain contusion and its relationship with wound age of mice. Methods A mouse brain contusion model was established with PCI3000 Precision Cortical Impactor. Expression changes of CB2R around the injured area were detected with immunohistochemical staining, immunofluorescent staining and Western blotting at different time points. Results Immunohistochemical staining results showed that only a few cells in the cerebral cortex of the sham operated group had CB2R positive expression. The ratio of CB2R positive cells gradually increased after injury and reached the peak twice at 12 h and 7 d post-injury, followed by a decrease to the normal level 28 d post-injury. The results of Western blotting were consistent with the immunohistochemical staining results. Immunofluorescent staining demonstrated that the changes of the ratio of CB2R positive cells in neurons, CB2R positive cells in monocytes and CB2R positive cells in astrocytes to the total cell number showed a single peak pattern, which peaked at 12 h, 1 d and 7 d post-injury, respectively. Conclusion The expression of CB2R after brain contusion in neurons, monocytes and astrocytes in mice suggests that it is likely to be involved in the regulation of the biological functions of those cells. The changes in CB2R are time-dependent, which suggests its potential applicability as a biological indicator for wound age estimation of brain contusion in forensic practice.

Effects of PI3K/Akt Pathway in Wound Healing Process of Mice Skin / 法医学杂志

OBJECTIVE@#To investigate the expressions and time-dependent changes of phosphatidylinositol-3-kinase (PI3K), phospho-PI3K (p-PI3K), protein kinase B (PKB/Akt) and phospho-Akt (p-Akt) during wound healing process of mice skin.@*METHODS@#The changes of PI3K, p-PI3K, Akt and p-Akt expression in skin wound were detected by immunohistochemistry, Western blotting and real-time PCR.@*RESULTS@#Immunohistochemistry showed the expression of PI3K and p-Akt were observed in mononuclear and fibroblast after skin wound, and reached peak in reconstruction. The positive bands of PI3K, p-PI3K, Akt and p-Akt were observed in all time points of the wound healing process by Western blotting. The expression peak of p-PI3K and p-Akt showed in inflammation and proliferation; the expression peak of PI3K and Akt in reconstruction. Real-time PCR showed the expression peak of PI3K mRNA in inflammation and reconstruction and the peak of Akt mRNA in reconstruction.@*CONCLUSION@#During the wound healing process, the expressions of PI3K, Akt, p-PI3K and p-Akt show different changes with significant correlation to wound time. The expression of PI3K/Akt may be a valuable marker for wound time estimation.

Time-dependent appearances of myofibroblasts during the repair of contused skeletal muscle in rat and its application for wound age determination / 法医学杂志

OBJECTIVE@#To research the relation between the time-dependent appearances of myotibroblasts during the repair of contused skeletal muscle in rat and wound age determination.@*METHODS@#A total of 35 SD male rats were divided into the control and six injured groups according to wound age as follows: 12 h, 1 d, 5 d, 7 d, 10 d and 14 d after injury. The appearances of myofibroblasts were detected by HE staining, immunohistochemistry and confocal laser scanning microscopy. Masson's trichrome staining was utilized to examine collagen accumulation in the contused areas.@*RESULTS@#Immunohistochemical staining showed that α-SMA+ myofibroblasts were initially observed at 5 d post-injury. The average ratio of myofibroblasts was highest at 14 d post-injury, with all samples, ratios more than 50%. In the other five groups, the average of α-SMA positive ratios were less than 50%. The collagen stained areas in the contused zones, concomitant with myofibroblast appearance, were increasingly augmented along with advances of posttraumatic interval.@*CONCLUSION@#The immunohistochemical detection of myofibroblasts can be applied to wound age determination. The myofibroblasts might be involved in collagen deposition during the repair of contused skeletal muscle in rat.

Correlation between percentages of PMN, MNC, FBC and wound age after skeletal muscle injury in rats / 法医学杂志

OBJECTIVE@#To study the percentages of polymorphonuclear leukocytes (PMN), mononuclear cells (MNC) and fibroblastic cells (FBC) in different post-traumatic intervals after skeletal muscle mechanical injury in rats.@*METHODS@#The rat model of skeletal muscle mechanical injury was established. The rats were divided into injured groups (6 h, 12 h, 1 d, 3 d, 7 d, 10 d and 14 d after injury) and control group. The percentages of PMN, MNC and FBC in different post-traumatic intervals after skeletal muscle mechanical injury were assessed with HE staining and image analysis.@*RESULTS@#At post-injury 6-12h, the percentages of PMN and MNC infiltration appeared in injured sites and that of PMN reached peak. At 1 d, the percentage of MNC infiltration appeared and reached peak, while that of PMN decreased. At 3-7 d, the percentage of FBC gradually increased, while that of PMN and MNC decreased. At 10-14d, the percentage of FBC reached peak.@*CONCLUSION@#The percentages of PMN, MNC and FBC in injured zones showed time-dependent changes, which might be used as reference index for determination of age of skeletal muscle injury.

Progress in myofibroblast and its application in forensic medicine / 法医学杂志

The myofibroblasts have dual characteristics of smooth muscle cells and fibroblasts. In repairing tissular wound, myofibroblasts are involved in fibrogenesis and remodeling the extracellular matrix of the fibrotic cascades reaction. The review describes the morphological characteristics and biological behaviors of myofibroblasts and the application of skin wound age determination, which may provide reference for research in forensic medicine.

Establishment of skin scald model in mice / 法医学杂志

OBJECTIVE@#To establish the model of skin scald in mice for the study of skin thermal injuries.@*METHODS@#After anaesthetization mice were scalded in a 1 cm-diameter circle area on the central dorsum by boiling water at contact times: 10s or 25s. The mice were sacrificed at 1, 3, 5, 7 and 10 days after scald. The skin samples were collected and analyzed by gross and histopathological examinations.@*RESULTS@#Deep II degree thermal injury involving full-thickness skin was observed in the 10s scald group. III degree thermal injury involving full-thickness skin and the dorsal skeletal muscle was observed in the 25 s scald group.@*CONCLUSION@#A mouse skin scald model is established which is stable and can be used on the skin thermal injury in future research.

The number of circulating fibrocytes of skeletal muscle in rats after contusion / 法医学杂志

OBJECTION@#To investigate the time-dependent appearance of circulating fibrocytes of skeletal muscle in rats after contusion.@*METHODS@#The model of skeletal muscle wound was established in rat. The circulating fibrocytes in contused skeletal muscle were detected by CD45 and procollagen I double immunofluorescence staining method.@*RESULTS@#In the control group, CD45- and procollagen I-positive cells were not detected in skeletal muscle. A few CD45 cells were observed aged from 6 h to 1 d after contusion. A few CD45- and procollagen I-positive cells (fibrocytes) initially gathered in injury area 3d after injury. The ratio of positive fibrocytes significantly increased 5 d after injury. The ratio of fibrocytes was highest at 7 d after contusion and then decreased. The volume of fibrocytes showed bigger with injury time increase compared with 3 d group. The expression of procollagen I and CD45 were weakened at 14d after injury.@*CONCLUSION@#The circulating fibrocytes are detected in contused skeletal muscle in time-dependent pattern. Circulating fibrocytes may be a marker in the wound age determination for contused skeletal muscle.

The expression of GABA(A) receptor alpha1 and GABA(B) receptor 1 in medulla oblongata solitary nucleus and ambiguous nucleus in the cases of tramadol intoxication / 法医学杂志

OBJECTIVE@#To observe the expression of GABA(A) receptor alpha1 (GABA(A)alpha1) and GABA(B) receptor 1 (GABA(B)1) in human medulla oblongata solitary nucleus and ambiguous nucleus due to tramadol-induced death.@*METHODS@#GABA(A)alpha1 and GABA(B)1 were detected by immunohistochemical SP method in tramadol-induced death group and control group. All results were evaluated by images analysis system.@*RESULTS@#Low expression of GABA(A)alpha1 and GABA(B)1 were detected in solitary nucleus and ambiguous nucleus in the control brain tissue. In cases of tramadol-induced death, the expression of GABA(A)alpha1 and GABA(B)1 significantly increased.@*CONCLUSION@#The mechanism of tramadol intoxication death could be caused by respiratory depression induced by over-expression of GABA(A)alpha1 and GABA(B)1 in medulla oblongata solitary nucleus and ambiguous nucleus.

Time-dependent recruitment and differentiation of fibrocytes in mouse skin wound healing / 法医学杂志

OBJECTIVE@#To investigate the time-dependent recruitment and differentiation of fibrocytes in skin wound healing.@*METHODS@#Fibrocytes (expressing CD45 and procollagen I ) and myofibroblasts (expressing CD45 and alpha-SMA) were co-localized by immunofluorescent staining. The number of fibrocytes and myofibroblasts was counted at different post-wounding interval.@*RESULTS@#At 3 d after injury, fibrocytes started to recruit at the margin of the wounds. At 5 d after injury, myofibroblasts started to appear in new formed granulation tissue. The number of fibrocytes and myofibroblasts peaked at 7 d post-wounding.@*CONCLUSION@#During skin wound healing, myofibroblasts in granulation tissue originated at least partly from fibrocytic differentiation. The time-dependent recruitment and differentiation of fibrocytes may provide new information for wound age determination.

Twenty autopsy cases of anaphylactic shock induced by cephalosporins / 法医学杂志

OBJECTIVE@#To explore the characteristics of autopsy cases of anaphylactic shock induced by cephalosporins and provide the evidences in forensic medicine.@*METHODS@#Twenty cases of anaphylactic shock induced by cephalosporins were collected from April 2005 to August 2009 in judicial expertise center of China Medical University, and the characteristics of the cases were analyzed retrospectively.@*RESULTS@#The age of decedents ranged from 40 to 60 years. Ninety percent of cases were from local medical centers and private clinics. The symptoms of the shock appeared 30 s-150 min after the administration of the drug, and death occurred 10 min-210 min after the appearance of the shock symptoms. In all cases, various degrees of eosinophil infiltration were observed in trachea and the lungs. Serum IgE detected by ELISA method was normal value in 14 cases.@*CONCLUSION@#In fatal anaphylactic cases, little specific findings are detected during postmortem and microscope examination. For this reason, the determination of cause of death in these cases requires comprehensive analysis combined with clinic information and excludes other diseases leading to the sudden death.