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Important forensic diagnostic indicators of sudden death in coronary atherosclerotic heart disease, such as acute or chronic myocardial ischemic changes, sometimes make it difficult to locate the ischemic site due to the short death process, the lack of tissue reaction time. In some cases, the deceased died of sudden death on the first-episode, resulting in difficulty for medical examiners to make an accurate diagnosis. However, clinical studies on coronary instability plaque revealed the key role of coronary spasm and thrombosis caused by their lesions in sudden coronary death process. This paper mainly summarizes the pathological characteristics of unstable coronary plaque based on clinical medical research, including plaque rupture, plaque erosion and calcified nodules, as well as the influencing factors leading to plaque instability, and briefly describes the research progress and technique of the atherosclerotic plaques, in order to improve the study on the mechanism of sudden coronary death and improve the accuracy of the forensic diagnosis of sudden coronary death by diagnosing different pathologic states of coronary atherosclerotic plaques.

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.

Talent is one of the basic and strategic supports for building a modern socialist country in all aspects. Since the 1980s, the establishment of forensic medicine major and the cultivation of innovative talents in forensic medicine have become hot topics in higher education in forensic medicine. Over the past 43 years, the forensic medicine team of Shanxi Medical University has adhered to the joint education of public security and colleges, and made collaborative innovation, forming a training mode of "One Combination, Two Highlights, Three Combinations, Four in One" for innovative talents in forensic medicine. It has carried out "5+3/X" integrated reform, and formed a relatively complete talent training innovation mode and management system in teaching, scientific research, identification, major, discipline, team, platform and cultural construction. It has made a historic contribution to China's higher forensic education, accumulated valuable experience for the construction of first-class major and first-class discipline of forensic medicine, and provided strong support for the construction of the national new forensic talent training system. The popularization of this training mode is conducive to the rapid and sustainable development of forensic science, and provides more excellent forensic talents for national building, regional social development and the discipline construction of forensic science.

Objectives: To investigate the effects of injury time, postmortem interval (PMI) and postmortem storage temperature on mRNA expression of glycoprotein non-metastatic melanoma protein B (Gpnmb), and to establish a linear regression model between Gpnmb mRNA expression and injury time, to provide aimed at providing potential indexes for injury time estimation., Methods: Test group SD rats were anesthetized and subjected to blunt contusion and randomly divided into 0 h, 4 h, 8 h, 12 h, 16 h, 20 h and 24 h groups after injury, with 18 rats in each group. After cervical dislocation, 6 rats in each group were collected and stored at 0 ℃, 16 ℃ and 26 ℃, respectively. The muscle tissue samples of quadriceps femoris injury were collected at 0 h, 12 h and 24 h postmortem at the same temperature. The grouping method and treatment method of the rats in the validation group were the same as above. The expression of Gpnmb mRNA in rat skeletal muscle was detected by RT-qPCR. The Pearson correlation coefficient was used to evaluate the correlation between Gpnmb mRNA expression and injury time, PMI, and postmortem storage temperature. SPSS 25.0 software was used to construct a linear regression model, and the validation group data was used for the back-substitution test., Results: The expression of Gpnmb mRNA continued to increase with the prolongation of injury time, and the expression level was highly correlated with injury time ( P <0.05), but had little correlation with PMI and postmortem storage temperature ( P >0.05). The linear regression equation between injury time ( y ) and Gpnmb mRNA relative expression ( x ) was y =0.611 x +4.489. The back-substitution test proved that the prediction of the model was accurate., Conclusions: The expression of Gpnmb mRNA is almost not affected by the PMI and postmortem storage temperature, but is mainly related to the time of injury. Therefore, a linear regression model can be established to infer the time of injury.

Medical disputes are one of the common problems concerned by the whole world. All countries and regions have established their own medical dispute resolution mechanisms, in accordance with their own national conditions. Medical dispute identification opinions, as one of the important bases for identifying the responsibilities of both doctors and patients, play a pivotal role in the process of dispute settlement. A reasonable medical dispute resolution mechanism and standardized medical dispute identification model can help resolve disputes flexibly and reduce the conflict between doctors and patients. This paper briefly compares the medical dispute resolution mechanism and identification mode of China and several other representative countries (the United States, Britain, France, Germany, Italy, Japan, etc.), and discusses their respective characteristics and shortcomings, to bring some enlightenment to the medical dispute resolution and identification in our country.

Objectives: To select four algorithms with relatively balanced complexity and accuracy among deep learning image classification algorithms for automatic diatom recognition, and to explore the most suitable classification algorithm for diatom recognition to provide data reference for automatic diatom testing research in forensic medicine., Methods: The "diatom" and "background" small sample size data set (20 000 images) of digestive fluid smear of corpse lung tissue in water were built to train, validate and test four convolutional neural network (CNN) models, including VGG16, ResNet50, InceptionV3 and Inception-ResNet-V2. The receiver operating characteristic curve (ROC) of subjects and confusion matrixes were drawn, recall rate, precision rate, specificity, accuracy rate and F 1 score were calculated, and the performance of each model was systematically evaluated., Results: The InceptionV3 model achieved much better results than the other three models with a balanced recall rate of 89.80%, a precision rate of 92.58%. The VGG16 and Inception-ResNet-V2 had similar diatom recognition performance. Although the performance of diatom recall and precision detection could not be balanced, the recognition ability was acceptable. ResNet50 had the lowest diatom recognition performance, with a recall rate of 55.35%. In terms of feature extraction, the four models all extracted the features of diatom and background and mainly focused on diatom region as the main identification basis., Conclusions: Including the Inception-dependent model, which has stronger directivity and targeting in feature extraction of diatom. The InceptionV3 achieved the best performance on diatom identification and feature extraction compared to the other three models. The InceptionV3 is more suitable for daily forensic diatom examination.

Diatom test is the main laboratory test method in the diagnosis of drowning in forensic medicine. It plays an important role in differentiating the antemortem drowning from the postmortem drowning and inferring drowning site. Artificial intelligence (AI) automatic diatom test is a technological innovation in forensic drowning diagnosis which is based on morphological characteristics of diatom, the application of AI algorithm to automatic identification and classification of diatom in tissues and organs. This paper discusses the morphological diatom test methods and reviews the research progress of automatic diatom recognition and classification involving AI algorithms. AI deep learning algorithm can assist diatom testing to obtain objective, accurate, and efficient qualitative and quantitative analysis results, which is expected to become a new direction of diatom testing research in the drowning of forensic medicine in the future.

Objectives: To explore the correlation between intestinal microbiota and postmortem interval(PMI) in rats by using 16S rRNA high-throughput sequencing technology., Methods: Rats were killed by anesthesia and placed at 16 ℃, and DNA was extracted in caecum at 14 time points of 0, 1, 2, 3, 5, 7, 9, 12, 15, 18, 21, 24, 27 and 30 d after death. The 16S rRNA high-throughput sequencing technology was used to detect intestinal microbiota in rat cecal contents, and the results were used to analyze the rat intestinal microbiota diversity and differences., Results: The total number of intestinal microbial communities did not change significantly within 30 days after death, but the diversity showed an upward trend. A total of 119 bacterial communities were significantly changed at 13 time points after death. The models for PMI estimation were established by using partial least squares (PLS) regression at all time points, before 9 days and after 12 days, reaching an R 2 of 0.795, 0.767 and 0.445, respectively; and the root mean square errors (RMSEs) were 6.57, 1.96 and 5.37 d, respectively., Conclusions: Using 16S rRNA high-throughput sequencing technology, the composition and structure of intestinal microbiota changed significantly within 30 d after death. In addition, the established PLS regression model suggested that the PMI was highly correlated with intestinal microbiota composition, showing a certain time series change.

Objective: To investigate the relationship between the expression of secreted frizzled-related protein 5 (SFRP5) mRNA and the time interval after skeletal muscle injury in rats by real-time PCR., Methods: A total of ninety SD rats were randomly divided into the contusion groups at different times including 4h, 8h, 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, 44h, 48h after contusion, incision groups at different times including 4h and 8h after incision and the control group. The samples were taken from the contused zone at different time points. The total RNA was isolated from the samples and reversely transcribed to analyze the expression levels of SFRP5 mRNA., Results: Compared to the control group, the expression of SFRP5 mRNA in contusion groups were down-regulated within 48 h after contusion and reached the lowest level at 20 h, and the expression of SFRP5 mRNA gradually increased from 20 h to 48 h after contusion. The expression of SFRP5 mRNA in the incised groups were significantly lower than that of the contusion groups at 4 h after injury. At the time of 8 h, the expression levels between the contusion and incision groups showed no statistically significant difference., Conclusion: It is suggested that SFRP5 mRNA analysis may show regular expression and can be a marker for estimation of skeletal muscle injury age.

Objective: To investigate the relation between injury time and the expression of cytochrome c oxidase subunit VIc (COX6C) mRNA in skeletal muscle of rat after contusion., Methods: A total of fifty-four SD rats were divided into the control group and the contusion groups (0.5, 1, 6, 12, 18, 24, 30, and 36 h after contusion), randomly. The contusion model was established by free fall drop of gravity hammer. At corresponding time point after contusion, the regular histology was examined and expression level of COX6C mRNA was tested by real-time PCR after extraction of total RNA from the tissues., Results: The main pathological features of 6 h after injury included edema and hemorrhage in myocytes with no inflammatory cells found. After 6 hours, the findings included myocyte degeneration and necrosis, inflammatory cells infiltration, and fibrous connective tissue proliferation in the contused zone. The expression level of COX6C mRNA was higher than that of the control group within 6 h after contusion. The expression level was lower than that of the control group from 6-36 h after contusion., Conclusion: The level of COX6C mRNA expresses in a regular way after contusion. It may be useful for estimating wound age in combination with the results of pathological features.

Objective: In order to understand which kind of function genes play an important role for estimating wound age, the variation of difference genes' mRNA expression were compared after injury., Methods: The mRNA expression levels of seven candidate genes (ICAM-1, NF-κB, MX2, MT1, MT2, sTnI, and Cox6c) were analyzed in contused rat skeletal muscle at different time points using real-time fluorescent quantitative PCR (RT-qPCR). The raw Ct values were normalized relative to that of RPL32 mRNA, and converted to standard Ct values. At each time point after injury, the standard deviations (SD) of the standard Ct values were calculated by SPSS., Results: The expression trends of the seven genes were all found to be related to wound age, but there were lower variation coefficients and greater reliability of s TnI and Cox6c when compared with other genes., Conclusion: The genes encoding structural proteins or proteins that perform basic functions can be suitable for wound age estimation.

Objective: To observe the effects of intermedin preconditioning on hypoxic injury in rat's cardiac myocytes and to provide the hypothetical mechanism of sudden cardiac death in the field of forensic pathology., Methods: The H9c2 cultured rat cardiac myocytes were randomly divided into control group, hypoxia group and IMD group. The myocardial cell viability, cellular ultrastructure, intracellular calcium concentration and apoptosis rate were determined by MTT assay, transmission electron microscopy, laser scanning confocal microscope and flow cytometry, respectively., Results: Compared with the control group, cell viability obviously decreased with inner ultrastructure injury in the hypoxia group (P<0.05), while cell viability significantly increased in the IMD group by reducing the hypoxia injury of cardiac myocytes (P<0.05). Compared with the control group, [Ca2+]i (fluorescence intensity) and apoptosis rate significantly increased in the hypoxia group, but decreased in the IMD group (P<0.05)., Conclusion: IMD increases the cell survival rate and decreases the cell apoptosis inhibited by intracellular calcium overload from hypoxia. This finding may reveal the mechanism of protective effects of myocardial hypoxia, and provide a scientific basis for the identification sudden cardiac death.

Objective: To explore the mRNA expression of microtubule associated protein-2 (MAP-2) after cerebral contusion, and to investigate its relationship with post-injury interval in a rat model of cerebral contusion., Methods: Based on Feeney's model of cerebral contusion, the time-dependent changes of MAP-2 mRNA were detected by real-time PCR method in different groups., Results: MAP-2 mRNA showed a lower expression in the brain of the control group. The expression of MAP-2 mRNA decreased 1 h post-injury, and reached the lowest level at 6 h, and the expression of MAP-2 mRNA gradually increased in the focus of the cerebral contusion from 12h to 14d after contusion, which kept a high level up to 14 d post-injury., Conclusion: The time-dependent changes of MAP-2 mRNA expression may be a new method for estimating the wound age of cerebral contusion in forensic practice.

Objective: To investigate the expression of intercellular adhesion molecular-1 (ICAM-1) mRNA in contused skeletal muscle of rats using fluorescence in situ hybridization (FISH) and its relationship with the contusion interval., Methods: To make the contusion models with rats skeletal muscle. The samples were taken to extract mRNA at 0.5 h, 1 h, 6 h, 12 h, 18 h, 24 h, 30 h and from the control group after contusion respectively. FISH was performed on frozen section samples and the sections were observed using LSCM., Results: The expression of ICAM-1 mRNA peaked at 6 h in skeletal muscle after contusion. Its level fell to 3.46 times the level of control group at 18 h and then increased again., Conclusion: The time-order expression of ICAM-1 mRNA in 30 hours after contusion is potentially useful for estimation of early wound age.

Objective: To investigate the expression of intercellular adhesion molecule-1 (ICAM-1) mRNA in contused skin and muscle of rats and the relationship between the ICAM-1 expression and the wound age., Methods: The samples were taken at 0.5, 1, 6, 12, 18, 24 and 30 h after contusion of rats, respectively. Total RNA was extracted both from the skin and muscle samples of each group and reverse transcription polymerase chain reaction (RT-PCR) was conducted to synthesize the 1st strand cDNA. The amount of ICAM-1 mRNA in each sample was quantified using rp132 intrinsic fluorescent assay and compared by the 2 (-Delta Delta Ct) method with that from control samples., Results: After contusion the expression of ICAM-1 mRNA in skin increased rapidly and peaked at 0.5 h, at 24 h degraded to the amount that was seven times as much as the control group, then rised again. The expression of ICAM-1 mRNA in muscle increased significantly within 0.5 h and peaked at 6 h, reached the minimum at 18 h, then increased again., Conclusion: It is suggested that ICAM-1 mRNA analysis may be useful for estimation of early wound age because of its time-related expression after contusion in skin and muscle.

Objective: To study the expression of substance P (SP) in human sudden erethistic death, and to seek objective morphological supports to diagnose sudden erethistic death for forensic medicine., Methods: The expression of SP was detected with immunohistochemical technique on 15 human laryngopharynx and gastrointestine of sudden erethistic death, and 20 sudden death of heart attack as control. The images of SP were analyzed by image analyzer, and the positive indexes (PI) were calculated., Results: SP expression in the experimental groups was significantly stronger than that in the control one (P < 0.001)., Conclusion: SP expression can offer an objective morphological reference support for forensic diagnosing sudden erethistic death.