International Journal of Legal Medicine最新文献

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.

Estimating individual age from DNA methylation at age associated CpG sites may provide key information facilitating forensic investigations. Systematic marker screening and feature selection play a critical role in ensuring the performance of the final prediction model. In the discovery stage, we screened for 811876 CpGs from whole blood of 2664 Chinese individuals ranging from 18 to 83 years of age based on a stepwise conditional epigenome-wide association study (SCEWAS). The SCEWAS identified 28 CpGs showing genome-wide significant and independent effects. Further restricting this panel to 10 most informative CpGs showed a tolerable loss of information. A linear model consisting of these 10 CpGs could explain 93% of the age variance (R² = 0.93) in the training set (n = 2664). In an independent test set of Chinese individuals (n = 648), this model also provided highly accurate predictions (R² = 0.85, mean absolute deviation, MAD = 3.20 years). The model was additionally validated in a public dataset of multiple ancestral origins (86 Europeans, 14 Asians, and 273 Africans) and the prediction accuracy reduced significantly (R² = 0.85, MAD = 6.21 years), as might be expected due to different genomic backgrounds, sample sizes, and age ranges. Our 10 CpG model also outperformed the recently proposed 9-CpG model constructed in 390 Chinese males (R² = 0.79 in test set). We also demonstrated that our SCEWAS approach outperformed the traditional EWAS and the elastic net approach in obtaining a small set of most age informative CpGs. Overall, our systematic genome-wide feature selection identified a small panel of 10 CpGs for accurate age estimation with high potential in forensic applications.

It is imperative in a forensic investigation to determine the identity of an unidentified corpse, for which a crucial starting point is to establish population affinity as part of the biological profile supplied by the forensic anthropologist. The present study investigates the feasibility of using multidetector computed tomography (MDCT) images to quantify craniometric variation between Japanese and Malay populations relative to the estimation of population affinity in a forensic context. The Japanese and Malay samples comprise MDCT scans of 252 (122 female; 130 male) and 182 (84 female; 98 male) adult individuals, respectively. A total of 18 measurements were acquired, and two machine learning methods (random forest modeling, RFM; support vector machine, SVM) were applied to classify population affinity. The accuracy of the two-way pooled-sex model was 88.0% for RFM and 94.5% for SVM, respectively. The four-way population and sex model produced an overall classification accuracy of 81.3% for RFM and 91.7% for SVM. The sex-specific models of population affinity showed correct rates of classification of more than 90% in both females (90.8% for RFM and 97.6% for SVM) and males (91.2% for RFM and 97.4% for SVM). Our findings clearly indicate that the cranial measurements acquired in MDCT images can be used for the forensic classification of Japanese and Malay individuals and thus serve as a reference for forensic anthropologists attempting to identify unidentified remains.

Alcohol consumption is widespread in most western countries such as Germany and a relevant risk factor for morbidity and mortality. Sensitive detection of alcohol consumption using suitable markers is therefore of central importance for clinical and forensic diagnostics. Direct alcohol markers are non-oxidative products of ethanol, which are produced in the body during the degradation of ethanol and provide high sensitivity and specificity. Phosphatidylethanol (PEth) is a promising marker for detecting alcohol consumption in the past days to weeks. The aim of this study was to determine the minimum amount of ethanol for a single alcohol consumption that leads to a detectable increase in blood PEth concentration. Therefore, 12 participants were recruited and, after four weeks of abstinence, drinking tests were carried out with target blood alcohol concentrations (BAC) of 0.6 g/kg and 0.75 g/kg. The PEth samples were obtained as dried-blood spots on the test day and the three following days and analyzed using LC-MS/MS. The result of the study were a detectable increase of PEth in the blood above limit of detection after both drinking events in all participants and an increase in PEth above the cutoff concentration for abstinence of 20 ng/mL in 9/12 (75%) and 7/12 (58%) participants, respectively, from a minimum BAC of 0.48 g/kg. These results make PEth appear promising as a marker for controlled moderate alcohol consumption.

The human neurocranium exhibits significant sexual dimorphism, making it a valuable resource for anthropological studies. This systematic review aggregated and analyzed data from literature on sex differences in neurocranial dimensions as measured by computed tomography (CT). Following registration of the review protocol with PROSPERO (#CRD 42023442451), comprehensive searches were conducted in six databases and gray literature. From an initial pool of 1,499 articles, 14 met the inclusion criteria and were analyzed for data extraction, meta-analysis of linear measurements, risk of bias (RoB), and certainty of evidence (GRADE) evaluation. In the meta-analysis (Sample size- 1726 female and 1837 male), the inverse variance method and a random-effects model were employed using Review Manager (version 5.4.1). Statistical heterogeneity was quantified using the I² coefficient. The studies primarily involved linear measurements between specific cranial landmarks, manually delineated using imaging software. Measurements analyzed included Maximum Cranial Length (G-Op), Cranial Base Length (N-Ba and N-Pfm), Cranial Height (Ba-Br), Frontal Chord (N-Br), Maximum Cranial Breadth (Eu-Eu), Minimum Frontal Breadth (Ft-Ft), Upper Facial Breadth (Fmt-Fmt), and Bimastoid Breadth (Ms-Ms). Results indicated that the mean values were significantly lower in females (p < 0.001), with no differences between the subgroups of dry skulls and living patients. The largest differences between sexes were observed in G-Op [-8.64 (-9.69, -7.59) mm] and N-Pfm [-8.83 mm (-12.75, -4.91)]. Our meta-analysis showed a low risk of bias, and measurements of N-Ba, Ba-Br, N-Br, and Ms-Ms demonstrated high certainty of evidence according to the GRADE approach. This research underscores the reliability of specific neurocranial measurements for sex differentiation in CT scans, with smaller dimensions consistently found in females.

Various concerns relating to international humanitarian law and human rights were risen by natural catastrophes (tsunamis, floods, fires), the Covid-19 pandemic, the epidemic breakouts of Ebola, as well as the significant migrant wave observed in the Mediterranean region. Forensic Medicine has direct interactions with both domestic and international law, and thus is frequently asked to provide solutions for these issues. The term "Humanitarian Forensic Action" (HFA), which refers to the application of forensic science to serve humanitarian endeavors, was created. The management of crises including armed conflicts, natural disasters, and humanitarian crises is therefore related to HFA. HFA is a specialized field of forensic sciences that is used to handle the identification of the deceased and human remains, as well as to contribute to the management of the dead, the management of mass disasters, and the investigation of abuse and torture. The psychosocial effects that these tragic events have on the victims, their loved ones, and society at large represent another HFA-related field. Firstly this systematic review aims to present all available international literature that discusses HFA as a unique forensic discipline. Secondly, through this review, it is hoped that HFA awareness will be risen among forensic practitioners, thus allowing improved adoption in general and future development as a branch of forensic sciences. As far as we are aware, there isn't another systematic study that presents the entirety of HFA's branches at once.

Human body decomposition significantly damages DNA, particularly short tandem repeats used in DNA profiling. In degraded samples, mitochondrial DNA (mtDNA) is used for aiding identification, utilizing hard tissues such as bones as DNA sources. However, extracting DNA from these tissues is complex and time-consuming. This study explores soft tissues for mtDNA analysis employing a next-generation sequencing (NGS) panel. A total of 290 samples from 30 autopsy cases were analyzed using an NGS panel targeting the entire mitochondrial genome. Among them, 239 samples were from 25 decomposed bodies with total body scores (TBS) ranging from 3 to 24. Nine types of soft tissue, including heart, liver, kidney, lung, brain, pectoralis muscle, iliacus muscle, aorta, and uterus, were examined. Rib cartilage, a representative hard tissue, and blood samples served as reference materials. Over 90% of the mtDNA sequence was confirmed in 49.6% of decomposed samples, increasing to 78.7% in hypervariable regions. As much as 95-100% of the mtDNA sequence could be retrieved from several highly decomposed soft tissues, comparable to rib cartilage. Among soft tissues, the uterus and aorta showed the shortest regions of uncovered mtDNA, highlighting their potential in decomposed bodies. No significant correlation was found between mtDNA sequencing quality and TBS or the nuclear DNA degradation index. The NGS panel successfully obtained most mtDNA sequences from decomposed soft tissues, suggesting that decomposition does not preclude genetic testing. Employing uterine or aortic tissues as alternatives to hard tissues in forensic contexts could streamline procedures, saving both time and resources.