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Objective To evaluate the effects of DNA examination of trace bloodstain samples from the scene collected with Trace Biological Evidence Collection kit. Methods Venous blood was made into bloodstains on the ground. The trace bloodstain samples were collected with Trace Biological Evidence Collection kit and common methods, respectively. DNA examination of trace bloodstain samples （50 from each group） was conducted on the constant temperature shaker for 2, 24, 48, 72, and 96 h, respectively, and the examination results of every group were compared. Results When the trace bloodstain samples were placed on the constant temperature shaker for 24, 48, 72, and 96 h, the DNA detection rates in the group which used Trace Biological Evidence Collection kit （100.00%, 100.00%, 100.00%, 96.00%） were significantly higher than those in the group using common methods （62.00%, 26.00%, 10.00%, 0）, the differences had statistical significance （P<0.05）. When the trace bloodstain samples were placed on the constant temperature shaker for 2 h, the differences of DNA detection rates between the two groups had no statistical significance （ P>0.05）. Conclusion The Trace Biological Evidence Collection kit can effectively improve DNA detection rate and extend detection time limit for trace bloodstain samples from the scene that have been stored for a relatively long time.
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Blood Stains , DNA , Forensic Medicine , TemperatureABSTRACT
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.
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Objective To discuss the effect of DNA extraction of bloodstain on the filter paper with four methods of solid phase absorption.Methods 180 bloodstain samples on the iflter paper, each one contains 1 microlitre anticoagulation peripheral venous blood, divided into 4 groups with 45 samples, respectively. All samples were treated with four methods of solid phase absorption, i.e. DNA IQ? System, D-shield sensitive DNA Extraction Kit, High efficiency Silica Bead DNA Extraction Kit and Conventional silica bead method. The concentration of DNA and the results of STR typing of four groups were compared each other.Results The concentration of DNA was 3.764±1.790μg/mL and 3.634±1.112μg/mL by using D-shield sensitive DNA Extraction Kit and High efifciency Silica Bead DNA Extraction Kit, respectively. However, the concentration of DNA by using Conventional silica bead method group (3.350±1.250) was not signiifcantly different from each other (P<0.05), while the concentration of DNA extracted with above three methods were higher than by using DNA IQ? System (1.864±1.207)(P<0.001); Signiifcant differences of peak height existed between DNA IQ? System and other three methods (P<0.001); As the same time, the peak height of samples by using High efficiency Silica Bead DNA Extraction Kit and Conventional silica bead method were signiifcantly different from D-shield sensitive DNA Extraction Kit (P<0.01).Conclusions The DNA extracted in bloodstain on the iflter paper by using D-shield sensitive DNA Extraction Kit, High efifciency Silica Bead DNA Extraction Kit and Conventional silica bead method was more than DNA IQ? System. Meanwhile, the quality of DNA using High efifciency Silica Bead DNA Extraction Kit and Conventional silica bead method may be higher.
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Bloodstain pattern analysis is a forensic discipline that reconstruct events of a crime scene by analyzing sizes, shapes, distributions, positions of bloodstains. Bloodstain pattern can be classified into the low velocity, medium velocity, and high velocity system. Velocities in this system represent the velocity of the wounding agent (the force applied) and not to the velocity of the blood in flight. Thus there is no reference system about the velocity of the blood in flight in the existing bloodstain classification system. Applying bloodstain pattern analysis to the real crime case, we needed to have the reference system of velocities of impact spatter, cast-off spatter, and expectorate spatter. Therefore we measured the velocities of these spatters using high speed camera and we analyzed the results. In this experiments the average velocity of impact spatter that generated by swinging a hammer with all experimenter's strength at the pool of blood is about 4.7 times faster than that of swing cast-off spatter that generated by swinging a red-wat hammer with all experimenter's strength, and about 3.9 times faster than that of expectorate spatter that generated by emitting blood from the mouth with all experimenter's strength. The velocities of cast-off spatter and expectorate spatter, however, showed similar distributions. Our experiments that measure the velocities of droplets of blood spatters in flight under the specific conditions that generated at fastest speed can give some reference to the classification system of velocities of bloodstains which is not distinct up to now, as well as some real bloodshed crime cases.
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Crime , Enzyme Multiplied Immunoassay Technique , MouthABSTRACT
Crime scene reconstruction is the use of scientific methods, physical evidence, deductive and inductive reasoning and their interrelationships to gain explicit knowledge of the series of events that surround the commission of a crime. Event analysis is the method of crime scene reconstruction. As disciplines of crime scene reconstruction, bloodstain pattern analysis and fire investigation have many common points. Comparing bloodstain pattern analysis with fire investigation in point view of event analysis helps us to further understand crime scene reconstruction as well as bloodstain pattern analysis and fire investigation themselves. We study event analysis and apply it to cases and we seek similarities and differences between bloodstain pattern analysis and fire investigation by analyzing the methodology of both of them. In a fire scene, the point with the greatest damage is the point where the fire burned longest, which is likely to be the origin. In bloodstained scenes this approach is reversed. The greatest bloodshed point is most likely the ending point of the incident and is likely at or near the point where the bloodshed started. Above this, there are other similarities between them. Mastering the crime scene reconstruction requires long time hard training. Thus if the fire investigation experts or arson experts among crime scene investigators join the field of bloodstain pattern analysis(or reverse), then there will be many synergy effects to both of them.
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Humans , Burns , Crime , Fires , Firesetting Behavior , Research PersonnelABSTRACT
OBJECTIVE To compare the effects of cleaning the bloodstain and other organic matter left on the bivalve speculum by 5 different cleaning methods.METHODS The following methods were adopted for 400 bivalve speculums with bloodstain left from gynecological operations:manual cleaning method,ultrasonic cleaning method,fully automatic cleaning method,artificial cleaning plus ultrasonic cleaning method,artificial cleaning plus fully automatic cleaning method,and the effects were detected by visual observation method,magnifier detection method and occult blood test method.RESULTS The positive rate of visual observation on 5 groups of bivalve speculums was 5.00%,3.75%,2.50%,0 and 0,respectively,the positive rate of magnifier detection was 7.50%,5.00%,3.75%,1.25% and 1.25%,respectively,and the positive rate of occult blood test was 15.00%,12.50%,8.75%,4% and 2%,respectively.CONCLUSIONS There are significant differences among 5 cleaning methods(P
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Objective To study time-dependent degradation of DNA in lymphocytes in the human bloodstain in order to estimate aging of bloodstain.Methods Lymphocytes were isolated from the human bloodstain placed under room temperature and were analyzed by single-cell gel electrophoresis(SCGE).The percentage of DNA-degraded lymphocytes were calculated in the cloodstain placed at different time intervals from 0 to 72h under fluorescent microscope connected with auto-analysis-image system.Results The percentage of DNA degraded lymphocytes was closely correlated with time lapse within 72h.A regression equation was formulated with R=0.9522(P
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0.05).The exclusion probability of Gc is 34.8% and discrimination probability of Gc is 79.44%.There are not any significant difference of the distribution of Gc subtypes between the Hun population in Chengdu and those in Hong Kong and Japanese.The difference of the distribution of Gc subtypes between the Han population in Chengdu and those in Malaysia,Indonesia,India as well as the American caucasians,Belgians,Icelander and West German are sig- nificant. The phenotyping of Gc in 11 bloodstain samples kept in room temperature for twenty weeks were carried out successfully also using PAGIF followed by immunofixation method.
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Objective To establish a simple and rapid new method for DNA extraction of FTA bloodstain samples.Methods Genomic DNA was extracted from FTA bloodstains of 1.2mm diameter by FTA-DNA direct extraction and FTA routine method respectively,and their genotypes were analyzed using ABI IdentifilerTM kit in 10?l and 25?l of reaction volume respectively.Results For 25?l of reaction volume,all DNA extracted by two different methods was successfully genotyped.For 10?l of reaction volume,however,the typing success rate of DNA extracted by FTA routine method was significantly lower than those by FTA-DNA direct extraction procedure.Using FTA routine method,the value of RFU ranged from 100 to 2000,and the peak imbalance result from preferential amplification of the smaller allele was a common phenomenon.Moreover,allelic dropout occurred in approximately nineteen percent of samples,and this was not obviously improved even if performed by automatic DNA workstation.However,using FTA-DNA direct extraction procedure,the typing results were similar to those in 25?l of reaction volume,and better results can be obtained using automatic DNA workstation.Conclusion The FTA-DNA direct extraction method is simple and rapid,and can be used to automatic establishment of DNA database with FTA bloodstains.
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The 340 blood samples from Guangdone area were detected by ultra thin poly-acrylamide gel isoelectric focusing for EAP phenotypes.The phenotypes were20 EAP A,119 EAP BA,201 EAP B.The gene frequencies of EAP were as foll- ows p~(?)0. 2338,p~(?)0. 7662. The 110 bloodstain samples of the cloth kept at roomtemperature for 7 weeks could be phenotyped correctly,The 21 bloodstain samp-les on the porcelain plate kept at room temperature for 9 weeks could be phen-otyped correctly.When the blood volume of bloodstain was equal to or over5?l EAP could be phenotyped.6 out of 20 mouldy bloodstains,the EAP BAphenotype were changed to EAP B.In blind trial,20 bloodstain samples kept atroom temperature for 7 weeds could be phenotped correctly.
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The investigation on distribution of Gm(2)facotor in 269 Chinese people living in Beijing was carried out using haemagglutination inhibition test and anti-Gm(2)sera from the Biotest Diagnosis of West Germany.Results revealed that Gm(2)factors was positive in 78 cases(29%),while negative in 191 cases(71%).Gm(2)phenotyping were(?)erformed successfully in 230 bloodstains, 14 months old,made of fresh blood selected from 269 samples of known Gm(2) phenotype.Detection of Gm(2)factors was carried out in 11 crime cases.Sus- pects were excluded in 4 cases.