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Journal of Forensic Medicine

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    28 December 2022, Volume 38 Issue 6 Previous Issue    Next Issue
    Original Articles
    Technique and Application
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    Original Articles
    Effects of Postmortem Hemolysis and Ultrafiltration on Creatinine Detection Results
    Yu-qing JIA, Tian-qi WANG, Rui ZHAO, Bao-li ZHU, Zhi-peng CAO
    2022, 38(6): 697-701.  DOI: 10.12116/j.issn.1004-5619.2021.410904
    Abstract ( 282 )   HTML ( 18 )   PDF (751KB) ( 522 )  

    Objective To investigate the interference of postmortem hemolysis on the detection of creatinine and whether ultrafiltration can reduce the interference. Methods A total of 33 non-hemolyzed whole blood samples from the left heart were collected. Hemolyzed samples with 4 hemoglobin mass concentration gradients H1-H4 were artificially prepared. Ultrafiltration was performed on each hemolyzed sample. Creatinine concentrations in non-hemolyzed serum （baseline serum）, hemolyzed samples and ultrafiltrate were detected. Bias （B）, Pearson correlation and receiver operator characteristic （ROC） of baseline creatinine concentration between before and after ultrafiltration were analyzed. Results As the hemoglobin mass concentration increased, B of the hemolyzed samples in the H1-H4 groups gradually increased, the |B| was 2.41（0.82，8.25）-51.31（41.79，188.25）, reaching a maximum of 589.06%, and there was no statistically significant between the creatinine concentration and the baseline creatinine concentration （P=0.472 7, r=0.129 5）. After ultrafiltration of hemolyzed samples, the interference of creatinine concentration in ultrafiltrate was significantly reduced, the |B| was 5.32（2.26，9.22）-21.74（20.06，25.58）, reaching a maximum of 32.14%, and there was a positive correlation with baseline creatinine concentration （P<0.05, r=0.918 2）. In the hemolyzed samples of H3 and H4 groups, there were 7 false-positive samples and 1 false-negative sample; in the ultrafiltrate samples, there were no false-positive sample and 1 false-negative sample. ROC analysis results showed the hemolyzed samples were lack of diagnostic value （P=0.117 5）. Conclusion The postmortem hemolysis significantly interferes creatinine detection results of blood samples, ultrafiltration can reduce hemolysis-induced interference in postmortem creatinine detection.

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    Characteristics of the Distance and Space Required for Knife Slashing Using a Motion Capture System
    Shu-fang YUAN, Shang-xiao LI, Chao-peng YANG, Bin NI, Wen-xia GUO, Yi SHI, Dong-mei WANG, Jia-hui PAN, Ming-zhi WANG, Wei-ya HAO
    2022, 38(6): 702-708.  DOI: 10.12116/j.issn.1004-5619.2021.411008
    Abstract ( 225 )   HTML ( 7 )   PDF (719KB) ( 408 )  

    Objective To investigate the relationship between the perpetrator’s sex, victim’s position and slashing location as well as anthropometric parameters on distance and space required for slashing, to provide the theoretical basis for the judgment of whether the crime scene was consistent with the criminal activity space. Methods The kinematics data of 12 male and 12 female subjects slashing the neck of standing and supine mannequins as well as the chest of the standing mannequins with a kitchen knife were obtained by using a 3D motion capture system. The relationship between the perpetrator’s sex-victim’s position, the perpetrator’s sex-slashing location, and anthropometric parameters and the distance and space required for the slashing were analyzed by two-factor repeated measures ANOVA and Pearson correlation analysis respectively. Results Compared with slashing the neck of supine mannequins, the distance （L） and normalized L （l） of slashing the neck of standing mannequins were greater, while vertical distance （LVR） and normalized LVR （lVR） of the knife side were smaller. Compared with slashing the neck of standing mannequins, the L and l slashing the chest of standing mannequins were greater, while LVR and lVR were smaller. Horizontal distance （LHR） and normalized LHR （lHR） of the knife side in males were greater than that in females. Height and arm length were positively correlated with L, LHR, and LVR when striking the standing mannequins. Conclusion When slashing the neck of supine or standing victims, the slashing distance is shorter and the slashing height is greater. Furthermore, the distance and space required for slashing are correlate with anthropometric parameters.

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    Analysis of Salivary Bacterial Community by Direct PCR and High Resolution Melting Curve and Its Forensic Applications
    Rui YANG, Jiong CHEN, Gui-sen ZHAO
    2022, 38(6): 709-718.  DOI: 10.12116/j.issn.1004-5619.2021.511006
    Abstract ( 194 )   HTML ( 3 )   PDF (2023KB) ( 376 )  

    Objective To develop a rapid test for salivary bacterial community based on direct PCR （dPCR） and high resolution melting （HRM） curve analysis, to evaluate its application value in forensic medicine. Methods The salivary bacteria were collected by centrifugation and then resuspended in Tris-EDTA （TE） buffer, and directly used as the template for amplification and HRM curve analysis （dPCR-HRM） of the 16S rDNA V4 region. The genotype confidence percentage （GCP） of the HRM profiles compared with the reference profile was calculated. The template DNA was extracted by traditional kit and then PCR-HRM （namely kPCR-HRM） was used as reference to validate the feasibility of dPCR-HRM. The gradient dilution templates, population samples and simulated salivary stains were analyzed by dPCR-HRM to evaluate its sensitivity, typing ability and adaptability. Results Using dPCR-HRM method, the HRM profiles of salivary bacterial community were obtained within 90 minutes. The GCP between dPCR-HRM and kPCR-HRM was greater than 95.85%. For general individuals, the HRM type of bacterial community could be determined with 0.29 nL saliva by dPCR-HRM. The 61 saliva samples could be divided into 10 types. The typing of salivary stains deposited within 8 h was the same as those of fresh saliva （GCP>90.83%）. Conclusion dPCR-HRM technology can be used for rapid typing of salivary bacterial community, and has the advantage of low cost and simple operation.

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    Application of Duplex Droplet Digital PCR Detection of miR-888 and miR-891a in Semen Identification
    Sun-xiang WEI, Hui-xiang CHEN, Sheng HU, Yi-xia ZHAO, Hui-xia SHI, Zhe WANG, Wen LI, An-quan JI, Qi-fan SUN
    2022, 38(6): 719-725.  DOI: 10.12116/j.issn.1004-5619.2021.510802
    Abstract ( 285 )   HTML ( 20 )   PDF (1825KB) ( 458 )  

    Objective To establish a system for simultaneous detection of miR-888 and miR-891a by droplet digital PCR （ddPCR）, and to evaluate its application value in semen identification. Methods The hydrolysis probes with different fluorescence modified reporter groups were designed to realize the detection of miR-888 and miR-891a by duplex ddPCR. A total of 75 samples of 5 body fluids （including peripheral blood, menstrual blood, semen, saliva and vaginal secretion） were detected. The difference analysis was conducted by Mann-Whitney U test. The semen differentiation ability of miR-888 and miR-891a was evaluated by ROC curve analysis and the optimal cut-off value was obtained. Results There was no significant difference between the dual-plex assay and the single assay in this system. The detection sensitivity was up to 0.1 ng total RNA, and the intra- and inter-batch coefficients of variation were less than 15%. The expression levels of miR-888 and miR-891a detected by duplex ddPCR in semen were both higher than those in other body fluids. ROC curve analysis showed that the AUC of miR-888 was 0.976, the optimal cut-off value was 2.250 copies/μL, and the discrimination accuracy was 97.33%; the AUC of miR-891a was 1.000, the optimal cut-off value was 1.100 copies/μL, and the discrimination accuracy was 100%. Conclusion In this study, a method for detection of miR-888 and miR-891a by duplex ddPCR was successfully established. The system has good stability and repeatability and can be used for semen identification. Both miR-888 and miR-891a have high ability to identify semen, and the discrimination accuracy of miR-891a is higher.

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    Structure Analysis of the Interfering Substance N-methyl-2-phenylpropan-1-amine of Methamphetamine in Wastewater
    Ting-ting ZHANG, Yu HUANG, Xue-jun ZHANG, Jie CHEN, Zhen-dong HUA
    2022, 38(6): 726-732.  DOI: 10.12116/j.issn.1004-5619.2022.320102
    Abstract ( 190 )   HTML ( 1 )   PDF (959KB) ( 376 )  

    Objective To analyze the chemical structure of the interfering substance that affects the result of methamphetamine analysis in wastewater. Methods A combination of GC-MS and liquid chromatography-quadrupole time-of-flight mass spectrometry （LC-QTOF-MS） was used to analyze the mass spectrum characteristics of the interfering substance that affects the result of methamphetamine analysis and to infer its possible structure. Liquid chromatography-triple quadrupole-mass spectrometry （LC-TQ-MS） was used to confirm the control material. Results Using LC-QTOF-MS in positive electrospray ionization （ESI+） mode, the mass-to-charge ratio （m/z） of quasi-molecular ion in the MS1 mass spectrometry of interfering substance was identical to that of methamphetamine, indicating that the interfering substance was probably an isomer of methamphetamine. The MS2 mass spectra obtained at three collision energies of 15 V, 30 V and 45 V were highly similar to methamphetamine, suggesting that the interfering substance contained methylamino and benzyl groups. Further analysis using GC-MS in electron impact （EI） ionization mode showed that the base peak in the mass spectrum of the interfering substance was at m/z 44. The interfering substance was confirmed to be N-methyl-2-phenylpropan-1-amine by compared with the standard reference. Conclusion The chemical structure of N-methyl-2-phenylpropan-1-amine is highly similar to methamphetamine, which is easy to cause interference for the detection of trace amounts of methamphetamine in wastewater using LC-TQ-MS. Therefore, in the actual analysis, the chromatographic retention time can be used to distinguish between N-methyl-2-phenylpropan-1-amine and methamphetamine.

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    Technique and Application
    Application of SifaInDel 45plex System in the Han and Mongolian Populations
    Guang-yuan YANG, Chun-yan YUAN, Rui-yang TAO, Ruo-cheng XIA, Ya-li WANG, Xin-yu DONG, Si-yu CHAI, Li-ming WU, Zhi-wei JIANG, Ting-ting JIANG, Kai-qin CHEN, Cheng-tao LI, Li-qin CHEN
    2022, 38(6): 733-738.  DOI: 10.12116/j.issn.1004-5619.2022.520801
    Abstract ( 139 )   HTML ( 2 )   PDF (706KB) ( 344 )  

    Objective To investigate the genetic polymorphism of InDel loci in SifalnDel 45plex system in the Han population in Jiangsu Province and the Mongolian population in Inner Mongolia, and to evaluate the effectiveness of the system in forensic medicine. Methods SifaInDel 45plex system was used for genotyping in blood samples of 398 unrelated individuals from the above two populations, and allele frequencies and population genetic parameters of the two populations were calculated respectively. Eight intercontinental populations in the gnomAD database were used as reference populations. The genetic distances between the two studied populations and eight reference populations were calculated based on the allele frequencies of 27 autosomal-InDels （A-InDels）. The phylogenetic trees and multidimensional scaling （MDS） analysis diagrams were constructed accordingly. Results Among two studied populations, the 27 A-InDels and 16 X-InDels showed no linkage disequilibrium between each other and the allele frequency distributions were in Hardy-Weinberg equilibrium. The CDP of the 27 A-InDels in two studied populations were all higher than 0.999 999 999 9, and the CPEtrio were all less than 0.999 9. The CDP of the 16 X-InDels in Han in Jiangsu and Mongolian in Inner Mongolia female and male samples were 0.999 997 962, 0.999 998 389, and 0.999 818 940, 0.999 856 063, respectively. The CMECtrio were all less than 0.999 9. The results of population genetics showed that the Jiangsu Han nationality, Inner Mongolia Mongolian nationality and East Asian population clustered into one branch, showing closer genetic relationship. The other 7 intercontinental populations clustered into another group. And the above 3 populations displayed distant genetic relationships with the other 7 intercontinental populations. Conclusion The InDels in the SifaInDel 45plex system have good genetic polymorphism in the two studied populations, which can be used for forensic individual identification or as an effective complement for paternity identification, and to distinguish different intercontinental populations.

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    Techniques and Applications
    Analysis of Genetic Polymorphism and Population Genetic Structure of 57 Autosomal InDel Loci in Beichuan Qiang Population
    Chun-yue JIANG, Hao MA, Qing-wei FAN, Hui-ling YANG, Dong-dong XU, Yun WANG, Bing DU
    2022, 38(6): 739-746.  DOI: 10.12116/j.issn.1004-5619.2021.511102
    Abstract ( 190 )   HTML ( 2 )   PDF (1150KB) ( 406 )  

    Objective To investigate the genetic information of 57 autosomal InDel loci （A-InDels） included in AGCU InDel 60 fluorescence detection kit in the Beichuan Qiang population of Sichuan Province and evaluate its application value in forensic medicine. Methods A total of 200 unrelated healthy individuals from Beichuan Qiang population of Sichuan Province were typing detected by AGCU InDel 60 fluorescence detection kit. Allele frequencies and population genetic parameters of the 57 A-InDels were statistically analyzed and compared with the available data of 26 populations. Results After Bonferroni correction, there was no linkage disequilibrium between the 57 A-InDels, and all loci were in Hardy-Weinberg equilibrium. Except for rs66595817 and rs72085595, the minor allele frequencies of 55 A-InDels were above 0.3. PIC ranged from 0.298 3 to 0.375 0, CDP was 1-2.974 8×10-24, CPEduo was 0.999 062 660, and CPEtrio was 0.999 999 999. The calculation of the genetic distance showed that Beichuan Qiang population had the closest genetic distances with Beijing Han and South China Han populations, but far away from African populations. Conclusion The 57 A-InDels in AGCU InDel 60 fluorescence detection kit have a good genetic polymorphism in Beichuan Qiang population of Sichuan Province, which can be used as effective supplemental for individual identification and paternity identification in forensic medicine.

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    Review
    Research Progress of DNA-Based Technologies for Postmortem Interval Estimation
    Lan YANG, Xin WANG, Yong NIU
    2022, 38(6): 747-753.  DOI: 10.12116/j.issn.1004-5619.2022.420601
    Abstract ( 447 )   HTML ( 4 )   PDF (663KB) ( 723 )  

    In criminal investigations, postmortem interval （PMI） is important information to be inferred in homicide investigations, as well as the focus and the difficulty in forensic pathology research. Because the DNA content in different tissues is relatively constant and shows changes regularly with the extension of PMI, it has become a research hotspot of PMI estimation. This paper reviews the recent progress of PMI estimation technologies including DNA-based single cell gel electrophoresis, image analysis, flow cytometry, real-time fluorescence quantitative PCR and high-throughput sequencing, hoping to provide references for forensic medicine practice and scientific research.

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    Research Progress of Exosomes and Their Forensic Significance
    Yuan-bo KANG, Si-fan WANG, Ting-jun CHEN, Ya-dong GUO, Chang-quan ZHANG
    2022, 38(6): 754-762.  DOI: 10.12116/j.issn.1004-5619.2021.410302
    Abstract ( 469 )   HTML ( 20 )   PDF (792KB) ( 710 )  

    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.

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    Application and Prospect of RNA Profiling Analysis in Forensic Body Fluid Identification
    Shou-yu WANG, Rui-yang TAO, Yi-ping HOU, Cheng-tao LI
    2022, 38(6): 763-773.  DOI: 10.12116/j.issn.1004-5619.2021.510707
    Abstract ( 418 )   HTML ( 2 )   PDF (1874KB) ( 701 )  

    In forensic physical evidence identification, the accurate identification of the individual origin and their body fluid composition of the biological samples obtained from the crime scene play a critical role in determining the nature of a crime. In recent years, RNA profiling has become one of the fastest developing methods for body fluids identification. Due to the characteristics of tissue or body fluid specific expression, various types of RNA markers have been proven to be promising candidate markers for body fluids identification in previous studies. This review summarizes the research progress of RNA markers in body fluids identification, including the RNA markers that have been effectively verified in current research and their advantages and disadvantages. Meanwhile, this review prospects the application of RNA markers in forensic medicine.

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    Application Value and Research Progress of Human Microbiome in Sexual Assault Cases
    Yang LIU, Min-min XU, Ya ZHANG, Shi-quan LIU, Mei-qing YUAN, Zhen-Jun JIA
    2022, 38(6): 774-782.  DOI: 10.12116/j.issn.1004-5619.2021.511101
    Abstract ( 295 )   HTML ( 3 )   PDF (740KB) ( 605 )  

    In recent years, sexual assault cases have been on the rise, seriously infringing the legitimate rights and interests of women and children, causing widespread concern in society. DNA evidence has become the key evidence to prove the facts in sexual assault cases, but lack of DNA evidence or only DNA evidence in some sexual assault cases leads to unclear facts and insufficient evidence. With the emergence of high-throughput sequencing technology and the development of bioinformatics and artificial intelligence, new progress has been made in the study of human microbiome. Researchers have begun to use human microbiome for difficult sexual assault cases indentification. This paper reviews the characteristics of human microbiome, and its application value in the inferences of the body fluid stain origin, the sexual assault method, the crime time, etc. In addition, the challenges faced by the application of the human microbiome in practical case handling, the solutions and future development potential are analyzed and prospected.

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    Progress of Keystroke Dynamics in Deception Research
    Tian-yu NAN
    2022, 38(6): 783-787.  DOI: 10.12116/j.issn.1004-5619.2021.110801
    Abstract ( 158 )   HTML ( 2 )   PDF (578KB) ( 348 )  

    Traditional polygraph techniques mostly rely on the changes of an individual’s physiological indicators, such as electrodermal activity, heart rate, breath, eye movement and function of neural signals and other indicators. They are easily affected by individual physical conditions, counter-tests, external environment and other aspects, and it is difficult to conduct large-scale screening tests based on the traditional polygraph techniques. The application of keystroke dynamics to polygraph can overcome the shortcomings of the traditional polygraph techniques to a large extend, increase the reliability of polygraph results and promote the validity of legal evidence of polygraph results in forensic practice. This paper introduces keystroke dynamics and its application in deception research. Compared with the traditional polygraph techniques, keystroke dynamics can be used with a relatively wider application range, not only for deception research but also for identity identification, network screening and other large-scale tests. At the same time, the development direction of keystroke dynamics in the field of polygraph is prospected.

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