Bacterial Succession on Rat Carcasses and Applications for PMI Estimation.

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.

Tuberculous abdominal aortic aneurysm with alimentary tract hemorrhage: a case report with medico-legal implications.

An autopsy case of sudden death induced by alimentary tract hemorrhage was presented, which was caused by the unexpected rupture of clinically unrecognized tuberculous abdominal aortic aneurysm (TAAA). The initial diagnosis was made of the syndrome of coronary heart disease and hypertensive disease. The detailed autopsy showed that the alimentary tract hemorrhage was caused by a sudden rupture of the mass after posture changing was ascertained as the cause of death. The diagnosis of TAAA was determined by the autopsy findings. Analysis for the medical dispute of TAAA was described, and the difficulty of the diagnosis and medico-legal implications were also discussed.

[Diagnosis of amniotic fluid embolism with blood samples by liquid-based cytology technique].

OBJECTIVE: To establish the diagnosis of amniotic fluid embolism with blood samples by liquid-based cytology technique and to study the validity of method. METHODS: The blood samples were collected from patients who suffered from amniotic fluid embolism. The components of amniotic fluid in blood samples were examined with blood smear by two direct smear methods (supernatant smear, sediment smear) and two liquid-based cytology methods (automatic smear, manual smear). The positive detection rate of each method was calculated. RESULTS: The positive detection rates of two liquid-based cytology methods (84.6% and 92.3%, respectively) were much higher than those of two direct methods (53.8% and 61.5%, respectively). CONCLUSION: The liquid-based cytology technique could improve the positive detection rate of amniotic fluid embolism.

Genetic polymorphism of nine non-CODIS STR loci in Hunan Province-based Chinese Han population.

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].

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].

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.

[Degenerate oligonucleotide primed-PCR technology establishment and its sensitivity test analysis].

OBJECTIVE: To establish a whole genome amplification testing system based on degenerate oligonucleotide primed-PCR (DOP-PCR) and to explore its reliability and sensitivity. METHODS: DOP-PCR amplified production was detected by fluorescent labeled multiplex STR amplification and capillary electrophoresis detection system to determine reliability and sensitivity of DOP-PCR system. RESULTS: DOP-PCR system was successfully established and the detection sensitivity reached 5 cells (30 pg) by pretreatment of DOP-PCR and then detection of STR genotyping. CONCLUSION: The system established in this study is reliable and more testing sensitive for forensic trace evidence.

An investigation and pathological analysis of two fatal cases of cadmium poisoning.

Pollution associated with population growth, and with industrial and urban development has led to a serious decline in the water quality of Chinese rivers. Cadmium (Cd) is recognized as one of the most toxic metals and is strongly accumulated by organisms. Humans are exposed to cadmium originating from the environment and from industrial pollution. In spite of thousands of published studies on Cd, there is little information on its pathological features seen in human autopsy. The gross and pathological findings of forensic autopsies of two case of cadmium poisoning are presented and related to an epidemiological investigation. In both cases, multiple organ damage was observed, involving brain, lung, liver, kidney, red blood cells, and platelets, which is consistent with reports in the literature. In particular, in both cases, transmission electron microscopy revealed a large number of dense lysosomal and phagocytic particles in the cytoplasm near the nucleus, indicating the need for a genotoxic study of cadmium. Our observations provide new clues for the future recognition and prevention of Cd poisoning.

[Comparison of mtDNA extracting methods for common sarcosaphagous insects].

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.

[Application of mtDNA polymorphism in species identification of sarcosaphagous insects].

Species identification of sarcosaphagous insects is one of the important steps in forensic research based on the knowledge of entomology. Recent studies reveal that the application of molecular biology, especially the mtDNA sequences analysis, works well in the species identification of sarcosaphagous insects. The molecular biology characteristics, structures, polymorphism of mtDNA of sarcosaphagous insects, and the recent studies in species identification of sarcosaphagous insects are reviewed in this article.

[Succession of sarcosaphagous insects at summer and autumn in Shijiazhuang area].

OBJECTIVE: To study the succession of sarcosaphagous insects and their regular activity on carcass in Shijiazhuang area. METHODS: Nine rabbits were sacrificed and placed at the same site during June to September in 2007-2009. The common species of sarcosaphagous insects were observed. RESULTS: Nine main species could be identified belonging to 3 families and 4 genera from Diptera, including Musca domestica (Linnaeus), Muscina stabulans (Fall én), Hydrotaea (Ophyra) capensis (Wiedemann), Hydrotaea (Ophyra) spinigera (Stein), Lucilia sericata (Meigen), Chrysomya megacephala (Fabricius), Boerttcherisca Peregrina (Robineau-Desvoidy), Parasarcophaga crassipalpi (Macquart) and Helicophagella melanura (Meigen). Eleven main species belonging to 4 families from Coleoptera include Nicrophorus concolor (Kraatz), Silpha carinata(Herbst), Nicrophorus fossor (Eneshas), Ptomascopus morio (Kraatz), Eusilpha bicolor (Fairmaire), Scarabaeus rugosus (Hausmann), Harpalus rufipes (DeGeer), Dolichus halensis (Schaller), Goncephalum pusillum (Fabricius), Cafius seminitens (Horn) and Aleochara pacifica (Casey). Two main species from 2 families were Tetramorium caespitum (Linnaeus) and Vespa velutina(Lepeletier). CONCLUSION: It is evident that the succession of sarcosaphagous flies in Shijiazhuang with its unique geographical features. It may be used for estimating postmortem interval in Shijiazhuang area.

[Advances on study of Lucilia species in estimating postmortem interval in forensic medicine].

Sarcosaphagous insects are very important to investigate some criminal cases. They are significant useful in estimating post-mortem interval (PMI) and corpse transfer post-mortem. Lucilia are very common sarcosaphagous insects. They like sunshine and are usually the earliest to touch the cadaver. These characteristics and others such as the stages of their larvae development can offer good evidences for criminal case investigation. This paper summarizes details of their application for estimating postmortem interval in recent years and reviews the methods to identify species and to determine the age of adult Lucilia with molecular biology and entomological morphology.

[Comparison of mtDNA extraction from different parts of sarcosaphagous insects].

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.

[Advances in the studies of postmortem interval estimation by the levels of chemical components in human vitreous humor after death].

Estimation of postmortem interval (PMI) is one of the problems that need to be solved for forensic examination of the dead body. Accurate estimation of PMI has great values to criminal investigation and trial. The levels of chemical components in human vitreous humor are changed with time after death, which can help estimate the PMI. The levels of certain chemical components, such as potassium, magnesium, ammonia, urea, creatinine, uric acid, hypoxanthine, lactic acid and so on, in human vitreous humor will gradually increase with time after death, while others such as calcium, sodium, enzymes, glucose, vitamin C and so on will decrease. The updates and advances in those studies were reviewed in this article.

[Extract human DNA from maggot crop contents by phenol-chloroform method coupled with paramagnetic particle method].

OBJECTIVE: To establish an effective phenol-chloroform method coupled with paramagnetic particle method for human DNA extraction from maggot crop contents in STR genotyping. METHODS: Human DNA was extracted from the maggot crop contents using phenol-chloroform method and purified by paramagnetic particle method. DNA was quantified by PCR with Quantifiler Human DNA Quantification Kit using 7500 real-time fluorescence quantitative PCR instrument. PCR products were genotyped by AmpFlSTR Identifiler PCR Amplification Kit using 3130XL-Avant genetic analyzer. RESULTS: The template DNA yield by the method described were increased at least 2 times than the phenol-chloroform extraction method alone. All of the full 16 STR profiles could be obtained with the samples extracted by this method when the DNA yield reached (0.218 +/- 0.041) ng/microL. CONCLUSION: Phenol-chloroform method coupled with paramagnetic particle method can effectively increase the sensitivity of STR analysis of human DNA recovered from maggot crop contents and is a valuable tool for forensic entomology.

[The succession of sarcophagus beetles on carrion and its application in forensic medicine].

Sarcophagus beetles, which can not be replaced by Diptera, play a pivotal role not only in estimating PMI of dry human skeletal remains in the later stages decomposition of carcasses, but also the corruption, destruction, decomposition and posture changes of carcasses. This article explicates the succession of sarcophagus beetles on carrion and its influencing factors, and introduces the application and prospects of sarcophagus beetles in forensic entomology. Although few researches focus on sarcophagus beetles at present, it is believed that more and more forensic scientists will pay attention to sarcophagus beetles' application in forensic identification.

[The development and application of lie detection in forensic science].

Lie detection technology has been applied increasingly to investigate and solve criminal cases. This article explores the evolvement of lie detection technology in the ancient times and the application of the psychological and physiological parameters which have become more accurate with the introduction of modern polygraph. The cognitive exploration and the application of Event Related Potentials (ERPs), functional Magnetic Resonance Imaging (fMRI), and Event-Related functional Magnetic Resonance Imaging (E-R fMRI) have made detection technology focus on the brain activities, which produce more objective results by tracing the original state of lying. In summary, this article describes different types of lie detections, simple and complex, their working principles, the latest development, and the prospect of their application in forensic science.

[Advances of the study of sarcosaphagous insects in forensic medicine].

The study of sarcosaphagous insects is a subspecialty in forensic medicine based on the knowledge of entomology. It could help to determine the time of death, especially the postmortem interval in decomposed cases. This paper explores its history, species and erosion process of sarcosaphagous insects. It reviews the species identifying methods with molecular biology and entomological morphology. Details of its application in estimating postmortem interval in recent years and study of sarcosaphagous insects in the field of forensic medicine are summarized.

[Evaluation of liquid based cytology test (LCT) in avoiding medical tangles].

OBJECTIVE: To evaluate of liquid based cytology test (LCT) in avoiding medical tangles. METHODS: One thousand five hundred five thirty one cases, which were collected from out-patients of precancerous lesions of uterine cervix, were randomly divided into three groups based on different smear preparation: LCT method was used in two groups (one with ThinPrep kit and one with ArtoBrain kit), conventional Papauicolaou smear (PS) was used in one group. All cases of abnormal cervical smears were identified by cytologic test underwent colposcopic examination and colopscopically multiple biopsy. Results of test were analyzed by software SPSS 11.0. RESULTS: Significant diference were found between LCT method and PS method compared by index of satifacation, sensitivity, specificity, accuracy, false negative rate and erroneous diagnosis rate (P < 0.05, but no difference were found between two LCT groups (ThinPrep kit and ArtoBrain kit). CONCLUSION: LCT method can improve diagnostic level of precancerous lesions of uterine cervix either tested by ThinPrep kit or ArtoBrain kit, so have the powerfull value to avoid medical tangles.