Objective To develop an HPLC-MS/MS method for simultaneous determination of xylazine and 2,6-xylidine in body fluid samples.Methods The samples were extracted by HLB SPE,separated by Waters Atlantis dC18 chromatographiccolumn,and then detected in the MRM scan ion mode under positive ionization condition.Results The recoveryrates of this method were between 70.5％ and 79.8％ with the range of RSD rfrom8.2％ to 10.5％.The limits of detection ofxylazine and 2,6-xylidine in blood and urine samples were 0.4 and 0.3 ng/mL,and the limits of quantitation were 1.2 and 1.0 ng/mL,respectively.Conclusion This method is of high sensitivity,good specificity and good reproducibility,and thus could besuitable for accurate quantification of xylazine in blood and urine samples.

Objective To successfully get the full PCR alleles of the Insertion/Deletion marker rs10644346 in which a SNP-binding exists at the 3'end region of the primer.Methods Based on the AS-PCR,a common forward primer and two reverse primers with allele-specific oligonucleotides at the last second 3'end instead of the terminus were tentatively designed for typing 150 unrelated individuals and 10 father-mother--child trios from Htnan province in South-central China.Simultaneously,9 samples were typed with all the above three primers (the two primer sets which consist of the common forward primer and one of the reverse primers).Results PCR amplicons were well detected in the 150 unrelated individuals after being typed with the three primers,and the amplified fragments of parental and filial generations among 10 father-mother-child trios conformed to Mendel's principles.Allele missing was found in the two-primer group.Conclusion The primers designed by locating the specific nucleotide at the last second 3'end rather than terminal position were demonstrated also effective in getting specific alleles if perfect mismatch and PCR conditions are guaranteed,and the design strategy can provide an optional reference to rescue markers of SNP-binding primers for forensic practice.

Objective To identify the species of sarcosaphagous flies by amplifying cytochrome oxidase subunitI (CO I) gene fragment,combined with morphological characteristics.Methods The DNA of sarcosaphagous flies was extacted by modified Tris balanced phenol-Tris saturated phenol protocol,the amplificationand sequencing of CO Ⅰ fragment were conducted,and the results were then compared with the database for analysis.Results The modified DNA extration method by Tris balanced phenol-Tris saturated phenol could obtain effective DNA of sarcosaphagous flies,and be applied for CO Ⅰ fragment amplification,and thus for identification of the species of sarcosaphagous flies.Conclusion The DNA extracted from sarcosaphagous flies by modified Tris balanced phenol-Tris saturated phenol protocol could be used astemplate for the amplification of CO Ⅰ fragment,and the system could identify the species of sareosaphagous flies after sequencing and alignment with the sequences of database.Compared with traditional identification methods of using morphological characteristics,the current system is more accurate and could be more widely applied.

Objective To study the correlation between the polymorphisms of NR3C1 gene and aggressive behavior in Yunnan Han population.Methods Five SNPs of the NR3C1 gene (rs6190,rs6191,rs6198,rs41423247 and rs56149945) were genotyped in 194 unrelated prisoners who committed violent-crimes and 301 healthy controls using improved Multiplex-ligase-detection reaction(iMLDR) method,and the data were statistically analyzed with the SPSS19.0soflware and PHASE2.1platform.Results Single locus analysis showed that the allelic distribution of rs6191and rs41423247did not show significant differencesbetween the control groupand the aggressive-behavior group as well as the robbery sub-group and intentional injury sub-group.However,significant difference was foundin the rs41423247 genotype distribution betweencontrol groupand robbery sub-group (p=0.048).In addition,there were no significant differences for the four haplotypes between the control group,the attack group,the robbery subgroup and the intentional injury subgroup.Conclusion These findings indicate that rs41423247 polymorphism of the NR3C1gene might play a role in susceptibility to aggressive behavior and rs6191 polymorphismmay not be correlated withaggressive behavior.

Objective This study aims to evaluate the changes of Cdk5 expression at the time of 3 hours to 10 days after moderate brain injury by blunt force impact in a rat model,and to demonstrate its forensic significance.Methods To establish a rat model of blunt focal brain contusion,and to observe the changes of Cdk5 expression in brain tissue at different timepoints after brain injury by immunohistochemistry and Western blot.Results A low expression level of Cdk5 was observed in the brain tissue of both normal and sham control groups.The expression of Cdk5 increased after 3 and 6 hours,remarkably increased at 12 hours,and reached the maximal level at 24 hours after focal brain injury.The Cdk5 level gradually decreased 3 days,5 days,7 days,and 10 days and reached the normal level 7 and 10 days after the injury,with no statistical difference (P＞0.05) compared with the normal and sham control groups.Conclusion The expression of Cdk5 increased in the peripheral area of contusion tissue after blunt brain injury in rats,showing single peak change,and dropped to normal level with the time extension.The change of Cdk5 expression may provide a new reference index for the prediction of early brain contusion.

Ethics review as the content of the research management of forensic medicine,is the research object of forensic medicine.Focusing on ethics review of the forensic medicine research,this paper discussed on the necessity of ethics review and guiding principles of ethics committee,and appealed for the construction of ethics review in forensic medicine research.

Objective To develop a highly sensitive luminescent reagent for bloodstain testing at forensic crime scenes.Methods Based ontheprincipleof ECL luminescence and the ping-pong conjugate activation principle of chemical electronic chain,this project developed a new type of highly sensitive luminescent reagent for bloodstain testing by usingthe uniform design of experimental methods to optimize the conditions andsynthesize several new compounds.Results The bloodstain testing luminescent reagentdeveloped in this project has high sensitivity andlongluminescence time.In the case of blood samples diluted by 1,000 times,reading the fluorescence withChemiScope 3300 chemiluminescence imaging system,the maximumvalue of gray scale reached 56,and the luminescence time lasted for 10 minutes.Conclusion The project has successfully developed a highly semitivebloodstain testing reagentthat could be applied to crime scene investigation.

Objective The aim of this study is to detect the mRNA and protein expression levels of ERCC1 and XPF genes among different age groups of healthy Chinese Han individuals,and to analyze the correlation between the mRNA and protein expression levels andthe age of individuals in order to find new molecular markers for forensic age estimation.Methods Peripheral blood samples were obtained from 150 unrelated healthy Chinese Han individuals.The plasma was centrifuged from the whole blood by gradient centrifugation,and the totalRNA was extractedwithTrizol fromperipheral blood mononuclear cells(PBMCs).Real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to quantitatively analyze the mRNA relative expression levels of ERCC1and XPF in PBMCs.Enzyme linked immunosorbent assay (ELISA) was used to quantitatively analyze the protein expression levels of ERCC1and XPF in plasma.Results There were no significant differences in the mRNA relative expression levels of ERCC1 and XPF in PBMCs between males and females(P＞0.05).Significant differences were found in the mRNA relative expression levels of ERCC1 and XPF between different age groups (P＜0.05).Regression analysis showed thatthe mRNA relative expression levels of ERCC1 and XPF were both negatively correlated with age.The correlation coefficients(r) were-0.578 and-0.844,respectively.When the age was used as independent variable(x) and the mRNA expression relative level as dependent variable (y),the fitting curveswere Y=3.3E-5X2-0.0261X+1.9175 (R2=0.3244,P＜0.01),Y=0.0003X2-0.0459X+2.0439 R2=0.729,P＜0.01),respectively.There were no significant differences inthe protein expression levels of ERCC1 and XPF in plasma between different age groups or genders (P＞0.05).Conclusion The mRNA relative expression levels of ERCC1 and XPF in PBMCsdeclined with the increase of age,however,the protein expression levels in plasma were unrelated to age.ERCC 1 and XPF genes can be used asnew molecular markers for forensic age estimation,so as to providetheoretical basis for establishing the mathematical model of ERCC1/XPF genesin concern ofindividual ages.

Objective To study age-related structural changes of proximal humerusin Chinese Han adults,for the application inage estimation.Methods Shoulder joint computed radiographs(CR) of 210 Chinese Han adults were sampled,with 124 males aging from 18 to 83 years old and 86 females aging 18 to 60 years old.Four observation indexes (the height of humerus bone marrow cavity,the change of trabecular bone in proximal humeral epiphysis,the change of trabecular bone in humeral macronodular and the change of trabecular bone in subacromial-clavicular bone marrow cavity) related with age were observed and scored.The regression equations of age estimation and change scores were established and tested statistically.Results Every index wasclosely correlated with the age changes inadults.The changes of trabecular bone in proximal humeral epiphysis and the changes of trabecular bone in subacromialclavicular bone marrow cavity have much better effects than the height of humerus bone marrow cavity and the changes of trabecular bone in humeral macronodular.The regression equations could predict the age of Chinese Han adults with satisfactory accuracy.Conclusion CR changes of the height of humerus bone marrow cavity,the changes of trabecular bone in proximal humeral epiphysis,the changes of trabecular bone in humeral macronodular and the changes of trabecular bone in subacromial-clavieular bone marrow cavity can bepracticallyusefulin age estimation for Chinese Han adults.

Objective To observe the change in IL-1β,IL-13mRNA expression in drowning rat lungs and serum,so as to investigate the significance of IL-1β and IL-13 mechanism in the development of drowning.Methods SD rats were randomly divided into control group,drowning group.Then using TaqMan probe method to determine the expression of IL-1β and IL-13 mRNA in Right lower lobe of lung tissue and the serum of right ventricle,which were extracted respectively from each group of rats.Results (1) The lung tissue morphological changes:Typical appearance signs and anatomy of drowning group meet ante-mortem drowning feature.(2) The expression of IL-1β,IL-13 in lung tissue:compared with the control group,the expression of IL-1β and IL-13 were slightly decreased,which has no statistical significance.(3) The expression of IL-1β and IL-13 in serum:compared with the control group,the expression of IL-1β and IL-13 were significant increased,both of which has statistical significance.Conclusion (1)The expression of IL-1β and IL-13 were decreased in lung tissue may be due to drowned rats present compensatory anti-inflammatory response syndrome which causes immune incompetent performance.(2) The expression of IL-1β and IL-13 were significant increased in serum may be relate to drown stress and drowning associated acute lung injury after traumatic stress.