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.

Species Identification of Sarcosaprophagous Flies Based on Vein Digital Image Analysis / 法医学杂志

Objective To identify species of common sarcosaprophagous flies based on digital image analysis of veins, in order to provide new idea for fast and accurate species identification of sarcosaprophagous flies in forensic entomology. Methods Random trapping of 226 male and female sarcosaprophagous flies that comprised of 7 common species, including Sarcophaga peregrina, Parasarcophaga ruficornis, Sarcophaga dux, Seniorwhitea reciproca, Bercaea cruentata, Aldrichina grahami, and Synthesiomysia nudiseta with carrion in the field was conducted. The 17 landmarks on the right wing of each fly were digitally processed and the images were analyzed. The effects of allometry were evaluated using a permutation test. Wing shape variations among 7 sarcosaprophagous fly species and female species was analyzed using canonical variate analysis （CVA）. Additionally, cross-validation test was used to evaluate the reliability of classification. Results Among 7 sarcosaprophagous fly species and female species, the effect of allometry had statistical significance （P<0.05）. The CVA results showed that among 7 sarcosaprophagous fly species and female species, differences in the wing shape were significant, and the first two canonical variates accounted for 82.9% and 84.1% of the total variation of vein shape. Vein digital image analysis can be used to separate the 7 common sarcosaprophagous flies, with an overall species identification accuracy of 81.2%-100.0%, and with a species identification accuracy of 75.0%-100.0% to distinguish the female flies of the 7 sarcosaprophagous flies species. Conclusion Vein digital image analysis is a relatively convenient and reliable method for identification of insect species, which can be used for species identification of common sarcosaprophagous flies.

Progress and Application of Entomological Evidence in Forensic Science / 法医学杂志

Entomological evidence provides entry points and clues for cases detection, in terms of estimation of the postmortem interval （PMI）, and place and cause of death. In recent years, the feasibility of entomological evidence in practice has been proved by theories and cases. It especially plays an important role in the investigation of cases with unnatural death, no monitoring, and highly corrupt cadaver. However, there are still some key issues to be further studied and standardized before the application of entomological evidence to forensic practice, to improve the effect of entomological evidence in forensic investigation and trial. This paper retrospectively reviews key studies of the application of entomological evidence in forensic science, mainly including discussion of forensic entomology inspection standard, identification studies of sarcosaprophagous insect species, collection of sarcosaprophagous insect growth and succession data under different environments and forensic entomotoxicology. With the rapid development of information technology and biotechnology, applying artificial intelligence and whole genome sequencing technology in forensic entomology has become a new research direction, which can improve the application value and range of entomological evidence in forensic science.

Effect of SOX7 promoter methylation on proliferation and apoptosis of bladder cancer / 医学研究生学报

Objective　The SOX7 gene plays a tumor-suppressive role in a variety of tumors, but there are few reports on whether it plays a role in bladder cancer. This study aims to investigate the expression of SOX7 gene in bladder cancer as well as to investigate the regulation and significance of SOX7 promoter methylation on bladder cancer.　Methods　GEPIA, Oncomine, MethHC, and cBioPortal databases were used to speculate the SOX7 expression and promoter methylation in bladder cancer tissues. 40 urine samples were collected from January 2017 to October 2017 in the Department of Urology, Tenth People's Hospital of Shanghai City, including 20 samples from bladder cancer patients and the rest 20 from regular patients as a control group. The methylation difference of SOX7 gene was detected by methylation-specific PCR. The bladder cancer cell line was cultured. The medium containing the methylated drug 5-aza-2’ deoxycytidine (5-aza-dc) was added to the Taza cells as the 5-aza-dc group, while T24 cells were added the same volume of DMSO as the control group. The bladder cancer cell line was transfected with the SOX7 plasmid as the plasmid group, and the transfected with the unloaded plasmid was the empty group. Western blot was used to detect the expression of SOX7 in bladder cancer cell lines, and the proliferation, clone formation, and apoptosis of bladder cancer cells after demethylation were detected by CCK-8 experiments, plate cloning experiments, and flow cytometry, respectively.　Results　The level of methylation in bladder cancer was significantly higher than that in healthy tissues (P<0.005). The higher levels of SOX7 methylation were observed in the urine of 15 bladder cancer patients (75%), compared with only 7 patients (35%) in normal urine, and the proportion was statistically different (P<0.05). The expression of SOX7 protein in the 5-aza-dc group was up-regulated compared to the control group. The expression of SOX7 protein was relatively high when the concentration reached 20 μmol/L. The expression of SOX7 protein in the plasmid group was significantly higher than that in the unloaded group. CCK-8 results showed that the A value of the 5-aza-dc group was statistically lower than that of the control group on the fifth day (P<0.05), and the A value of T24 cells in the plasmid group was significantly lower than that in the unloaded group. The colony formation experiment showed that the number of colony formation per well in the 5-aza-dc group (167.33 ± 13.65) was significantly lower than that in the control group (328.00 ± 20.81) (P<0.05). The number of clone formation per well in the plasmid group (136.00 ± 15.00) was significantly lower than that in the unloaded group (280.67 ± 13.43) (P<0.05). The apoptosis rate of T24 cells in the 5-aza-dc group (27.89%) was significantly higher than that of the control group (3.79%) (P<0.05), and the apoptosis rate of the plasmid group (21.28%) was higher than that of the no-load group (9.90%).　Conclusion　SOX7 is lowly expressed in bladder cancer, which is regulated by promoter methylation. It is a potential biological marker of bladder cancer and plays a vital role in the occurrence and development of bladder cancer.

Prospects of Application of Microbial Biofilm to Estimate PMI of Corpses in Water / 法医学杂志

In forensic pathology, the estimation of postmortem interval （PMI） has always been a difficult issue, and there is still lack of effective methods to estimate PMI of corpses in water. Microbial biofilm refers to the microbial population attached to non-biological or biological surfaces by microorganisms during microbial growth, that has a three-dimensional structure, surrounded by extracellular polymers and matrix networks created by itself. A series of community succession phenomena of microorganisms occur during the occurrence and development of microbial population. The microbial community and its succession process of this kind of biofilm attached to the surface of a corpse in water may become a new basis for estimation of the PMI of corpses in water. This review elucidates on the concept, classification, research methods, and influencing factors of biofilm and analyzes its application prospects in PMI estimation of corpses in water, which would provide new ideas for the researches in this field.

Retrospective Analysis on 1 900 Cases of Medical Malpractices / 法医学杂志

Objective To study the change trend, distribution characteristics and causes of medical malpractices in 18 years, through retrospective analysis of 1 900 cases of medical malpractices, in order to provide guidance for the precaution and the treatment of medical malpractices. Methods A thousand and nine hundred medical malpractice cases that were accepted by Hunan Xiangya Judical Identification Center from 2000 to 2017 were collected. Statistical analysis on the caseloads, the clients, the department distributions, the levels of the hospital and the causes of medical malpractices, etc were conducted. Results The number of cases commissioned by third-party accreditation agencies for medical fault identification was on the rise; The clients of medical malpractices changed significantly in 18 years. Most of the medical malpractice cases occurred in secondary and tertiary hospitals, significantly more in surgery, obstetrics and gynecology. The occurrence of medical malpractices was related to the doctor's insufficient prediction of the severity of the disease and the possible complications, and failure to fully inform the relevant duty of care, etc. Conclusion China's medical malpractice solutions and medical fault identification procedures are gradually improving. Strengthening the medical malpractice precaution awareness of medical workers in surgery, obstetrics and gynecology will be conducive to resolution of medical malpractices.

Research Progress of Vitreous Humor Detection Technique on Estimation of Post-mortem Interval / 法医学杂志

Estimation of postmortem interval(PMI)plays a crucial role in forensic study and identifica-tion work. Because of the unique anatomy location, vitreous humor is considered to be used for estima-ting PMI, which has aroused interest among scholars, and some researches have been carried out. The detection techniques of vitreous humor are constantly developed and improved which have been gradually applied in forensic science, meanwhile, the study of PMI estimation using vitreous humor is updated rapidly. This paper reviews various techniques and instruments applied to vitreous humor detection, such as ion selective electrode, capillary ion analysis, spectroscopy, chromatography, nano-sensing technology, automatic biochemical analyser, flow cytometer, etc., as well as the related research progress on PMI es-timation in recent years. In order to provide a research direction for scholars and promote a more accu-rate and efficient application in PMI estimation by vitreous humor analysis, some inner problems are also analysed in this paper.

Chemical constituents from the twigs and leaves of Cryptomeria fortunei / 中成药

AIM To study the chemical constituents from the twigs and leaves of Cryptomeria fortunei Hooibrenk ex Otto et Dietr.METHODS The ethyl acetate fraction of 95％ ethanol extract from C.fortunei was isolated and purified by silica,MCI,and Sephadex LH-20 column,then the structures of obtained compounds were identified by physicochemical properties and spectral data.RESULTS Eleven compounds were isolated and identified as isopimaric acid (1),sandaracopimaric acid (2),acetylisocupressic acid (3),imbricataloic acid (4),isocupressic acid (5),pinifolic acid (6),13-epicupressic acid (7),19-acetylagathadiol (8),agatadiol (9),phytol (10),elemol (11).CONCLUSION Compounds 1-10 are identified as diterpenoids and compound 11 is identified as sesquiterpenoid;Compounds 2,3,6-11 are obtained from this plant for the first time.

Genetic Polymorphisms of 21 STR Loci in Hunan Province-based Han Population / 法医学杂志

OBJECTIVES@#To investigate the genetic polymorphisms of 21 short tandem repeat （STR） loci （D3S1358, D13S317, D7S820, D16S539, Penta E, D2S441, TPOX, TH01, D2S1338, CSF1PO, Penta D, D10S1248, D19S433, vWA, D21S11, D18S51, D6S1043, D8S1179, D5S818, D12S391 and FGA）.@*METHODS@#A total of 560 blood samples were collected from unrelated healthy individuals of Han population in Hunan Province. Chelex-100 extraction method was applied to the extraction of genomic DNA, and an AGCU EX22 Kit and 9700 STR amplification was used in amplification reactions. The products were separated and analyzed on 310 Genetic Analyzer.@*RESULTS@#A total of 248 alleles were observed, the allelic frequencies ranging from 0.001 to 0.518. Observation of genotype distributions for each locus showed no deviations from Hardy-Weinberg equilibrium except Penta E （P=0.023）. The combined power of discrimination, combined power of exclusion, and combined matching probability of the 21 STR loci were approximately 0.999 999 999 999 999 999 999 999 8, 0.999 999 998, and 1.36×10⁻²⁵, respectively.@*CONCLUSIONS@#The 21 STR loci show high polymorphisms in the Han population, which can provide valuable data and a theoretical basis for forensic individual identification and paternity testing.

The Origin and Development of Medical Jurisprudence in Xiangya / 法医学杂志

The origin of medical jurisprudence in China can be traced back to as early as 1920s, and since then, the discipline has undergone a great development. This paper, based on the disciplinary development of medical jurisprudence at Xiangya School of Medicine, illustrates its evolution in three aspects covering the scientific and theoretic foundation, legal system and policy support. The current investigation reflected a glimpse of the modern forensic science in China, providing useful historical reference for the development of Chinese forensic science.

Bacterial Succession on Rat Carcasses and Applications for PMI Estimation / 法医学杂志

UNLABELLED@#Abstract:@*OBJECTIVE@#To investigate the bacterial succession on rat carcasses and to evaluate the use of bacterial succession for postmortem interval (PMI) estimation.@*METHODS@#Adult female SD rat remains were placed in carton boxes. The bacterial colonization of circumocular skin, mouth and vagina was collected to be identified using culture-dependent biochemical methods. The changes in community composition were regularly documented.@*RESULTS@#The bacterial succession in three habitats showed that Staphylococcus and Neisseria were predominated in early PMI, especially Staphylococcus aureus and Neisseria lactamica in 6 hours after death. Lactobacillus casei developed on the 3-4 days regularly, and kept stable at a certain level in late PMI.@*CONCLUSION@#The involvement of normal and putrefactive bacteria in three body habitats of rat remains can be used for PMI estimation.

Genetic polymorphism of nine non-CODIS STR loci in Hunan Province-based Chinese Han population / 法医学杂志

OBJECTIVE@#To determine the allelic frequency distribution and genetic parameters of nine non-CODIS DNA index systems of the short tandem repeat (STR) loci (D2S1772, D6S1043, D7S3048, D8S1132, D11S2368, D12S391, D13S325, D18S1364, and GATA198B05).@*METHODS@#A total of 353 blood samples were collected, extracted, amplified, and analyzed from unrelated healthy individuals of Han nationality in Hunan Province, China.@*RESULTS@#One hundred and fourteen alleles were observed in the population with corresponding allelic frequencies ranged from 0.001 0 to 0.323 0. For all the nine non-CODIS STR loci, the observed genotypic data showed no significant deviations from the Hardy-Weinberg equilibrium. The Ho, He, PIC, DP, and PE of the studied non-CODIS STR loci ranged from 0.1080 to 0.1950, 0.8050 to 0.8920, 0.7700 to 0.8600, 0.9250 to 0.9660 and 0.6070 to 0.7800, respectively.@*CONCLUSION@#Nine non-CODIS STR loci have high degrees of polymorphisms, which may be useful in individual forensic identification and parentage testing in forensic practice.

Reflection of estimating postmortem interval in forensic entomology and the Daubert standard / 法医学杂志

Estimating postmortem interval (PMI) is always the emphasis and difficulty in forensic practice. Forensic entomology plays a significant indispensable role. Recently, the theories and technologies of forensic entomology are increasingly rich. But many problems remain in the research and practice. With proposing the Daubert standard, the reliability and accuracy of estimation PMI by forensic entomology need more demands. This review summarizes the application of the Daubert standard in several aspects of ecology, quantitative genetics, population genetics, molecular biology, and microbiology in the practice of forensic entomology. It builds a bridge for basic research and forensic practice to provide higher accuracy for estimating postmortem interval by forensic entomology.

Identification of sarcosaphagous Calliphorid flies by analyzing the sequence of 16S rDNA / 法医学杂志

OBJECTIVE@#To explore the application of a 289bp fragment of the 16S rDNA gene to identify various species of sarcosaphagous Calliphorid flies.@*METHODS@#Twenty-six Calliphorid flies were collected from 14 Chinese provinces. All specimens were properly assigned into three genera and six species. The DNA of the pectoralis was extracted using CTAB method. Then PCR amplification was done for the 289 bp fragment of the 16S rDNA gene. The PCR products were then purified and sequenced, and the obtained sequences were uploaded to GenBank. The phylogenetic tree was built by the neighbor-joining method and intraspecific and interspecific divergences were calculated by sequence analysis.@*RESULTS@#The above 26 sarcosaphagous flies could be well clustered according to different genera and species. The evolutional intraspecific values were all zero, the evolutional interspecific variations varied from 0.3% to 6.5%.@*CONCLUSION@#The 289 bp fragment of the 16S rDNA of sarcosaphagous flies can be effectively used to identify most of the flies at species level. This method appears to be fast and low dissipative, which might be used to estimate postmortem interval by sarcosaphagous flies.

Comparison of mtDNA extracting methods for common sarcosaphagous insects / 法医学杂志

OBJECTIVE@#To compare effects of three different methods for mtDNA extraction from common sarcosaphagous insects including cetyl trimethyl ammonium bromide (CTAB) method, sodium dodecyl sulfate-potassium acetate (SDS-KAc) method and sodium dodecyl sulfate-proteinase K (SDS-PK) method.@*METHODS@#Seventy-two insects from four species [Chrysomya megacephala (Fabricius, 1784), Eusilpha bicolor (Fairmaire, 1896), Paraeutrichopus pecoudi (Mateu, 1954), Vespa velutina (Lepeletier, 1836)] were collected from the corpses of the rabbits in Changsha district. The total DNA of above samples was extracted by CTAB, SDS-Kac and SDS-PK methods. The purity and concentration of DNA were examined by protein-nucleic acid spectrophotometry, and mtDNA were amplified by specific primers and PCR products were detected by agarose gel electrophoresis. Then PCR products were sequenced and subsequently up-loaded to GenBank.@*RESULTS@#mtDNA was successfully extracted with three methods from most of the samples. The SDS-PK method was better in DNA purity compared to other methods and the CTAB method was superior in extracting DNA from old samples, while SDS-KAc method showed no significant difference for extraction effects of different samples.@*CONCLUSION@#The most appropriate method should be chosen depending on different situations. SDS-PK method is expected to obtain high-quality DNA, while CTAB method is preferred in extracting obsolete samples. SDS-KAc method is low cost and can be used in various kinds of preliminary experiments.

Comparison of mtDNA extraction from different parts of sarcosaphagous insects / 法医学杂志

OBJECTIVE@#To explore mitochondrial DNA (mtDNA) extraction effects of different parts from sarcosaphagous insects using improved cetyltriethylammnonium bromide (CTAB) method.@*METHODS@#Thirteen Lucilia sericata (Meigen) and 13 Nicrophorus fossor (Erichson) were collected from the corpses of rabbits placed on the outdoor lawn in Huhehot district. Four parts (head, chest muscle, legs and wings) of insect were collected, and the mtDNA of all samples were extracted using CTAB method. The purity and concentration were tested using protein and nucleic acid spectrophotometry. The integrity of the extracted mtDNA and PCR products were checked by agarose gel electrophoresis. The PCR products were sequenced and the obtained sequences were imputed into GenBank for comparison.@*RESULTS@#mtDNA were successfully extracted from 10 head samples, 6 legs samples, 4 wing samples and 13 chest muscle samples of the Lucilia sericata (Meigen). Also, mtDNA were successfully extracted from 5 head samples, 8 legs samples, 3 wing samples and 13 chest muscle samples of the Nicrophorus fossor (Erichson).@*CONCLUSION@#mtDNA can be obtained from chest muscle and other parts of sarcosaphagous insects using the improved CTAB method.

Forensic analysis of 74 tumor related medical malpractice cases / 法医学杂志

OBJECTIVE@#To analyze the causes of medical malpractice in patients with tumor, to determine the medical responsibility, and to recommend the related preventions.@*METHODS@#Seventy four medical malpractice cases, which were involved in tumor and collected from 2000 to 2009 in medicolegal expertise center of west China, were analyzed retrospectively.@*RESULTS@#The medical malpractice cases in the patients with tumor showed an increasing tendency in recent years. The main causes are missed diagnosis, misdiagnosis, improper chemotherapy and neglect of complications. The causes of medical malpractice were different in the different levels of medical services. The occurrence of medical malpractice in surgery and OB-GYN showed more frequent than the others.@*CONCLUSION@#Forensic pathology autopsy is important to resolve medical malpractice of tumor patients by finding out the cause of death and clarifying the medical responsibility. The occurrence of medical malpractice could be reduced by the clinical doctors through improving serve consciousness, obtaining the patients' trust, improving the medical treatment, following related laws and rules, fulfiling duty of medical careness.