International Journal of Legal Medicine最新文献

Traumatic Brain Injury (TBI) represents one of the leading causes of disability and death globally, with a significant impact on public health. We present 12 cases (age 5-80 years old) of death due to TBI with different post-traumatic interval (PTI). The expression of S-100B and RIPK-1 in pericontusional zones of TBI were studied in forensic cases to understand the vitality and timing of injuries. The anti-RIPK-1 antibodies mainly stained the cytoplasm of the nerve cells. In 3 cases (48 to 56 years old with no other comorbidities; PTI: 2 days to 4 days) antibodies positive for RIPK-1 were found. In 5 cases (48 to 71 years old; PTI: 2 days to 12 days) astrocyte, oligodendrocyte and neurons positive for anti-S-100B were found. In 3 of these 5 cases both antibodies tested were positive. In 7 cases (5-80 years old; one with history of drug abuse, other with no comorbidities, PTI 0 h; ) the glial cells were swollen and the submeningeal glial limitans became immunopositive for S100B. Stain accumulations were also observed adjacent to the walls of cerebral vessels, sometimes within the intravascular compartment. The results of the study show that in subjects who suffered a TBI, the expression of RIPK-1 and S-100B at the level of neurons in the pericontusional area was significantly increased compared to the control group. Neurons were not stained for RIPK-1 in cases of sudden cardiac deaths and sudden deaths due to TBI but observed neurons became immunopositive for RIPK-1 some days after TBI. S100-immunopositive neurons were not seen in immediate deaths but were found in cases with survival up to 12 days. Results regarding S100B are in line with existing knowledge. The study of necroptosis with anti-RIPK-1 antibodies could be useful in understanding the extent of secondary injuries and survival time in forensic contexts. However, this is a pilot study and should be extended to a larger number of cases to achieve more reliable results.

Determining the time since deposition (TsD) and sex of saliva stains is crucial for revealing the time of the crime's occurrence and clarifying the nature of the crime. This process not only shortens the time required to solve the case but also helps narrow down the scope of investigation, thereby enhancing the efficiency of case resolution. Currently, the forensic study of the microbial composition in long-term saliva stains remains a relatively underexplored field. The purpose of this study was to explore the succession pattern of long-placed human saliva stains microbial communities and identify relevant microbial markers for estimating TsD and identifying the sex of the donor, in order to be an effective alternative tool for solving practical forensic cases. Therefore, in this study, saliva stains exposed to indoor environmental conditions for up to 140 days were collected and 16S rRNA full-length sequencing was performed using single-molecule real-time sequencing technology based on the PacBio sequencing platform. The study reveals that after 140 days of placement, the relative abundance of Firmicutes significantly decreased (p = 0.00304). At the genus level, the relative abundances of Streptococcus (p = 0.0008), Rothia (p = 0.0448), Gemella (p = 0.016), and Veillonella (p = 0.0208) also significantly decreased. Additionally, significant differences were found in the microbial communities between saliva stains from males and females (p = 0.00013). Then, we constructed a TsD estimating model for microbial community markers based on random forest, and the results showed that the mean absolute error was 9.59 days, and the accuracy of sex classification model based on stepwise logistic regression model and 4 bacterial markers was 84.21%. This indicates that saliva stains that have been in place for a long time still retain significant forensic value, and microbial markers can be used to determine the time since deposition (TsD) of dried saliva stains as well as to identify the sex of the donor.

DNA identification of human skeletal remains play a valuable role in the forensic field, especially in missing persons and mass disasters investigation. Hard tissues, such as bones and teeth, represent a very common kind of samples analyzed in forensic laboratories because often they are the only biological materials remaining. However, the major limitation in using these compact samples rely on time consuming and labor-intensive treatment of grinding them into powder before proceeding with the conventional DNA purification and extraction step. In this context, a novel DNA extraction assay, called the TBone Ex kit (DNA Chip Research Inc.), was developed to digests bone chips without powdering "as reported by Kitayama (JAMA 12:84-89, 2010)." Here, we simultaneously analyzed bone and tooth samples obtained by our police laboratory that belonged to 15 different forensic cases from Sardinia (Italy). The total of 27 samples were recovered from different scenarios and were exposed to extreme environmental factors, including sunlight, seawater, soil, fauna, vegetation and high temperature and humidity. The TBone Ex kit was used prior to the EZ2 DNA extraction kit on the EZ2 Connect Fx instrument (Qiagen), and high quality autosomal and Y-chromosome STRs profiles were obtained for the 80% of the cases, in a relatively short time frame. This study provides additional support for the use of the TBone Ex kit for digesting bone fragments/whole teeth as an effective alternative to pulverization protocols. We empirically demonstrated the effectiveness of the kit in processing multiple bone samples simultaneously, largely simplifying the DNA extraction procedure, and the good yield of recovered DNA for downstream genetic typing in highly compromised forensic real specimens. In conclusion, the results of this study appear useful for forensic laboratories, to which the various actors of the criminal justice system - such as potential jury members, judges, defense attorneys and prosecutors - require immediate feedback.

Background: Sexual violence (SV) while travelling internationally is underreported and pre-travel advice is often focussed on broader tourist safety concerns. International travellers who experience sexual violence face particular challenges. The aim of this paper was to analyse the attendances of people who disclosed having been subjected to SV during international travel to the Sexual Assault Treatment Unit (SATU) network in the Republic of Ireland.

Methods: Analysis of all people who attended the national SATU network who disclosed an incident of SV experienced during international travel, and comparison of these cases with domestic case attendances.

Results: During the 7-year period studied, there were 6,447 attendances to the national SATU network, with 443 incidents reported as occurring outside Ireland; in 66 separate countries. The mean age of international attendees was 26.61 years, with females representing 90.3% of cases. Where an incident occurred internationally, the patient was less likely to disclose drug ingestion in the 24 h preceding the incident (p < 0.001) and significantly less likely to be assaulted in the assailant's home (p = 0.009) when compared with domestic cases. Those who were assaulted internationally were significantly more likely to be assaulted by a stranger or recent acquaintance, i.e. ( p < 0.001).They were also more likely be assaulted in a location recorded as 'other indoors' (e.g. hotel, hostel etc) (p < 0.001). There was no significant difference in alcohol consumption (p = 0.115) or frequency of assaults occurring outdoors (p = 0.155).

Conclusion: Our study has shown that 7% of attendances to the SATU network followed incidents of SV that occurred during international travel. The majority of these incidents were disclosed as being perpetrated by a stranger or recent acquaintance, in an indoor setting with over half having occurred in Europe. Individuals who experience SV while travelling abroad should be encouraged to seek immediate medical attention and appropriate follow-up care upon returning home.

Postmortem interval (PMI) estimation, a parameter critical for solving criminal cases, remains a challenge. It has been suggested that elasticity of decomposing tissue may show a relationship to PMI. We measured elasticity of excised porcine skin at regular intervals for 17 days using a novel ultrasound device. Kruskal-Wallis test followed by Dunn's pair-wise comparison test was performed on the elastic modulus values from each time-point. We found statistically significant differences (p < 0.0001) between the elastic modulus values. Pair-wise comparison showed that tissue measured with a PMI of 1-4, 6-9, 10-14, and 16-17 days can be distinguished from each other based on elastic modulus values. An overall trend of increasing elastic modulus values with time was also observed. Histology and H&E staining of skin samples at PMI of 1, 5, 8, and 12 days showed increasingly prominent fibre bundles which may explain the observed trend. The results of our study suggest that estimation of PMI using an ultrasound device is promising and should be explored further.

In forensic practice, identifying the species of unknown bodily fluid stains can provide assistance in the qualitative analysis and investigation of cases, and vaginal fluid stains, as one of the common bodily fluid stains, are most commonly seen at the scene of sexual assault. At present, the commonly used vaginal peptidase or microscopic detection methods currently have drawbacks such as high false negative rates, poor sensitivity, and high requirements for sample integrity and background color. However, in forensic investigations, the test materials have specificity and scarcity, making it difficult to ensure their quantity and quality. Thus, in order to achieve rapid and sensitive detection of vaginal fluid stains, in this study, we combined nested PCR and isothermal amplification technology to construct a rapid detection system for suspicious vaginal fluid stains using lateral flow dipstick. This system achieves detection by detecting the specific marker microbial community Lactobacillus crispatus in vaginal fluid, and has a high sensitivity and accuracy, which can achieve detection at template quantities as low as 2.31 copies. More importantly, the system can achieve detection at a constant temperature of 37 °C without the need for complex instruments. It can provide rapid and sensitive identification results, providing assistance for subsequent forensic material extraction and individual identification.

Disaster victim identification and criminal investigations have intensified the demand of complex kinship testing. Compared to close relatives, distant relatives share fewer identical-by-descent genetic segments; therefore, more genetic markers are required to improve the system effectiveness. Driven by the progress of next-generation sequencing, several commercial or in-house panels, including a large number of genetic markers, have been developed and applied in forensic caseworks. However, few efficient panels are available for first cousins (FC) kinship testing. Here, we adopted the MGIEasy Pa-SNPs genotyping kit, a two-step multiplex PCR strategy to detect 2,009 SNPs, and evaluated their system effectiveness in complex kinship analysis. Samples from 10,000 pairs of relatives and unrelated individuals were simulated to evaluate the system power. Simultaneously, real samples were used to further confirm this, including 72 pairs of full siblings (FS), 52 pairs of uncle/aunt/-niece/nephew (UN), 92 pairs of FC, 79 pairs of first cousin once removed (1C1R), and 780 pairs of unrelated individuals. The results showed that this kit was sufficiently powerful in FS, UN, and FC versus unrelated kinship testing and could also discriminate part of 1C1R relatives against unrelated individuals. This method was also powerful in the kinship determination of FS versus UN, FS versus FC, FS versus 1C1R, and UN versus 1C1R kinship testing but had limited power to determine UN versus FC and FC versus 1C1R relationships. This study provides an effective strategy and guidance for complex kinship analysis in forensic practice.

Formalin-fixed tissues possess irreplaceable value as a source of DNA for identification, especially when fresh samples are unavailable. Nonetheless, extracting and amplifying DNA from these tissues is challenging, primarily due to formaldehyde-induced cross-linking and nucleic acid fragmentation. In this study, two pre-extraction treatments, gradual dehydration using ethanol and pre-digestion heat treatments, and three DNA extraction methods, the Chelex-100 method, TIANamp FFPE DNA Kit, and ML Ultra-micro DNA extraction kit, were utilized to optimize DNA extraction from different tissues, which were fixed in 4% unbuffered formalin for different durations. The tissues include the heart, liver, spleen, lung, kidney, muscle, and brain. DNA quality was assessed, and quantification was conducted using Spectrophotometer and Quantifiler^® Trio DNA Quantification Kits, while the GSTAR™ 25 kit was employed for STR detection. The results indicated that the two pre-extraction treatments exhibited no significant effect on the STR success rate. On day 9, allelic dropout was observed in the heart, liver, spleen, lung, and kidney tissues. Furthermore, allelic dropout was observed in muscle and brain at 12 days and 15 days, respectively. In conclusion, the results underscore the feasibility of effectively extracting DNA from formalin-fixed tissues within 9 days for subsequent STR analysis.

Adverse drug reactions and fatalities can result from therapeutic drug use due to genetic deficiencies in drug-metabolizing enzymes. In cases where ancillary testing may not reveal a clear cause of death, molecular autopsies can be valuable. However, forensic mortuaries do not retain DNA samples in all cases, which hinders subsequent genetic testing if it is later deemed necessary. This study aimed to evaluate whether post-mortem whole blood samples collected for toxicological analysis, could provide viable DNA for genetic testing after varying storage periods. Thirty deceased individuals were recruited with informed consent. Blood collected at autopsy from each individual was stored in two sodium fluoride/potassium oxalate (gray-top) tubes, two additive-free (red-top) tubes and one ethylenediaminetetraacetic acid (EDTA; purple-top) tube- the latter recommended for DNA analysis. Blood from one gray-top and one red-top tube were sampled for toxicological analysis prior to DNA analysis, while the remaining samples (acting as controls) underwent DNA analysis immediately. DNA analysis involved DNA extraction and DNA concentration and degradation assessment. Blood samples were stored at 4 °C and DNA extraction and analysis was repeated one year and then five years later. Toxicological sampling did not significantly influence DNA results. DNA concentration and quality significantly decreased over time for all sample types, with DNA from red-top tubes showing the greatest decline. The study showed that DNA testing for drug-metabolizing enzymes was feasible on whole blood that had been stored for five years. This finding supports the potential for retrospective genetic testing in cases of adverse drug reactions and fatalities.

Fall from a height trauma is characterized by a multiplicity of injuries, related to multiple factors. The height of the fall is the factor that most influences the kinetic energy of the body and appears to be one of the factors that most affects the extent of injury. The purpose of this work is to evaluate, through machine learning algorithms, whether the autopsy injury pattern can be useful in estimating fall height. 455 victims of falls from a height which underwent a complete autopsy were retrospectively analyzed. The cases were enlisted by dividing them into 7 groups according to the height of the fall: 6 or less meters; 9 m, 12 m, 15 m, 18 m, 21 m, 24 m or more. Autoptic data were registered through the use of a previously published visceral and skeletal table. A total of 25 descriptors were used. Reduction of values in the range, standard and robust scaling were used as preprocessing methods. Principal Component Analysis, Single Value Decomposition and Independent Component Analysis were applied for dimensionality reduction. Cross validation was performed with 5 internal and external folds to ensure the validity of the results. The learning algorithms that generated the best models were Linear Regression, Support Vector Regressor, Kernel Ridge, Decision trees and Random forests. The best mean absolute error was 4.58 ± 1.28 m when dimensionality reduction was applied. Without any dimensionality reduction, the best result was 4.37 ± 1.27 m, suggesting a good performance of the proposed algorithms, with better performance when dimensionality is not automatically reduced.