离子交换柱法萃取血样中4种巴比妥类药物

目的建立血样中4种常见巴比妥类药物的固相萃取方法。方法采用Oasis MAX固相萃取柱对样品进行预处理,以2%氨水淋洗2,%甲酸-甲醇洗脱,GC/NPD定量检验,GC/MS定性检验。结果血样中4种常见巴比妥类药物平均萃取回收率达80%以上,以信噪比10/1计,最小定量限为1～2μg/mL,以信噪比3/1计,检出限为0.5～1μg/mL,在1～50μg/mL范围内,线性相关系数均在0.99以上。结论本文固相萃取方法检出限低,回收率高,选择性强,可应用于血样中4种常见巴比妥类药物的检测。     

Direct detection of blood in fingermarks by MALDI MS profiling and Imaging

The determination of the presence of blood in fingermarks constitutes important intelligence in a criminal investigation as it helps to reconstruct the events that have taken place at a scene of crime. Various methodologies have been reported and are currently employed for the detection of the presence of blood including optical, spectroscopic and chemical development approaches. However, most methods only give an indication that blood may be present and, therefore, these methods are described as presumptive tests.Here we show the use of Matrix-Assisted Laser Desorption Ionisation Mass Spectrometry Profiling and Imaging (MALDI MSP and MALDI MSI) for the determination of the presence of blood in fingermarks by specifically detecting the molecules of haem and haemoglobin through their mass-to-charge ratios. Furthermore, preliminary experiments are shown which demonstrate that this technology is compatible with other methods currently employed for enhancing fingermarks in blood (or contaminated by blood). The application of the developed protocols to a crime scene blood trace, demonstrates the feasibility of using this technology in routine casework. These findings open up a new line of research for the development of robust MALDI MSP and MALDI MSI protocols for the detection and chemical imaging of bloodied marks.     

SNPs and MALDI-TOF MS: tools for DNA typing in forensic paternity testing and anthropology

DNA markers used for individual identification in forensic sciences are based on repeat sequences in nuclear DNA and the mitochondrial DNA hypervariable regions 1 and 2. An alternative to these markers is the use of single nucleotide polymorphisms (SNPs). These have a particular advantage in the analysis of degraded or poor samples, which are often all that is available in forensics or anthropology. In order to study the potential of SNP analysis in these fields, 41 SNPs were selected on the basis of following criteria: conservation, lack of phenotypic expression, and frequency of occurrence in populations. Thirty-six autosomal SNPs were used for genotyping 21 inclusionary and 3 exclusionary paternity cases. The behavior of 5 X-chromosome SNPs was analyzed in a French representative population. Our approach to SNP typing is a multiplex PCR based amplification followed by simultaneous detection by primer extension (PEX) analyzed by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). The selected autosomal SNPs showed independent inheritance and gave clear results in paternity investigation. All X-SNPs were useful as both paternity and identification markers. PEX and MALDI-TOF MS, with their high sensitivity, precision and speed, gave a powerful method for forensic and anthropological exploitation of biallelic markers.     

Discriminant function analysis for sex assessment in pelvic girdle bones: sample from the contemporary Mexican population

Sex assessment of skeletal remains plays an important role in forensic anthropology. The pelvic bones are the most studied part of the postcranial skeleton for the assessment of sex. It is evident that a population-specific approach improves rates of accuracy within the group. The present study proposes a discriminant function method for the sex assessment of skeletal remains from a contemporary Mexican population. A total of 146 adult human pelvic bones (61 females and 85 males) from the skeletal series pertaining to the National Autonomous University of Mexico were evaluated. Twenty-four direct metrical parameters of coxal and sacral bones were measured and subsequently, sides and sex differences were evaluated, applying a stepwise discriminant function analysis. Coxal and sacra functions achieved accuracies of 99% and 87%, respectively. These analyses follow a population-specific approach; nevertheless, we consider that our results are applicable to any other Hispanic samples for purposes of forensic human identification.     

液相色谱-串联质谱法检测血液中的美西律

目的建立测定血液中美西律(mexiletine)的液相色谱-串联质谱联用法(LC-MS/MS)。方法采用简便的乙腈蛋白沉淀法对血液进行预处理,应用Allure PFP Propyl液相柱分离,用电喷雾正离子模式离子化,多反应监测模式对美西律进行分析。结果美西律与内标纳洛酮分离良好,在0.02～10.00μg/mL内线性关系良好,相关系数为0.9999,回归方程为y=0.0283x-0.0151,日内与日间精密度的RSD均小于15%,最低检测限为0.01μg/mL。结论建立的LC-MS/MS方法简单、灵敏、可靠,可同时适用于美西律临床药物监测和法医毒物分析的需要。     

Technological innovation in the recovery and analysis of 3D forensic footwear evidence: Structure from motion (SfM) photogrammetry

The recovery of three-dimensional footwear impressions at crime scenes can be a challenge but can also yield important investigative data. Traditional methods involve casting 3D impressions but these methods have limitations: the trace is usually destroyed during capture; the process can be time consuming, with a risk of failure; and the resultant cast is bulky and therefore difficult to share and store. The use of Structure from Motion (SfM) photogrammetry has been used widely to capture fossil footprints in the geological record and while there is a small body of work advocating its use in forensic practice the full potential of this technique has yet to be realised in an operational context. The availability of affordable software is one limiting factor and here we report the availability of a bespoke freeware for SfM recovery and subsequent analysis of for footwear evidence (DigTrace). Our aim here is not to provide a rigorous comparison of SfM methods to other recovery methods, but more to illustrate the potential while also documenting the typical workflows and potential errors associated with an SfM based approach. By doing so we hope to encourage further research, experimentation and ultimately adoption by practitioners.     

固相萃取-GC/MS法检测生物检材中的百草枯

目的采用固相萃取-气相色谱/质谱分析方法检测血液、尿液和脏器组织中的百草枯。方法人血液、尿液和猪肺组织样品经三氯乙酸去除蛋白后,取上清用十二烷基三甲基溴化铵和十二烷基硫酸钠处理过的C18小柱提取,提取物用硼氢化钠在碱性条件下还原,产物用气相色谱/质谱法分析,外标法定量。结果生物检材中百草枯回收率为78%～87%,最低检出限为0.1μg/mL,在0.5～1mg/mL范围内线性关系良好,可对实际案例检材进行定量检测。结论本文固相萃取-气相色谱/质谱分析方法能满足中毒生物检材检验及临床毒物检验需要。     

浮游生物PCR检测及其在溺死鉴定中的研究进展

溺死鉴定是法医学中的重点和难点之一,目前在相关法医学案件中,主要采用法医病理学尸检与传统硅藻检验等方法综合分析进行鉴定。传统硅藻检验存在灵敏性较低,易于污染等不足。采用PCR法检测尸体不同脏器组织中是否存在水中浮游生物的DNA标记,适用范围广,信息量丰富,灵敏性和特异性较高,有较好的法医学应用前景,有望成为鉴定溺死的新方法。本文对相关研究进展进行综述,为相关研究和实践参考。     

Medicolegal assessment of blood transfusion errors--an interdisciplinary challenge

Given a current total incidence of erroneously administered blood transfusions of 1:12,000-1:36,000 (AB0 incompatible 1:38,000), the percentage of lethal outcomes ranges between 2 and 5%; i.e. the sole fact of an erroneous transfusion does not mandatorily result in a causal connection with lethal outcome, which can give rise to problems in the medicolegal assessment. We report on the conception and results of a novel interdisciplinary approach to assess the lethal significance of blood transfusion errors. Besides autopsy, histological investigation and immunohistochemical detection of AB0 incompatible foreign red blood cells in autopsy specimens, transfusion medicine investigations offer the opportunity to assess several immunohaematologic features. We assessed the immunohaematologic gel card ("microcolumn") technique for suitability in the forensic assessment of an AB0 incompatible transfusion incident in a septic patient, who had had no history of previous blood transfusions, with lethal outcome. After such an erroneous transfusion had been simulated in vitro, pre-transfusion and cadaver patient blood samples (p.m. interval: 3 days) were analysed. Amongst other things, IgG-loaded erythrocytes were detected in pre- and post-transfusion samples; the presence of irregular antibodies directed against blood group antigens and anti-A or anti-B isoagglutinins, respectively, especially in the pre-transfusion sample was ruled out. Besides the demonstration of AB0 incompatible red blood cells in the cadaver blood sample, blood group incompatibilities other than AB0 were excluded. With regard to the cause of death, in synopsis with autopsy findings and clinical symptoms, the results did not allow for a final discrimination between the impact of the pre-existing septic inflammatory response syndrome and sepsis, respectively, and potential lethal effects of a (haemolytic) transfusion reaction. Besides pre- and post-transfusion compatibility testing in clinical transfusion medicine as required by German National Guidelines, the reported immunohaematologic investigations offer an important supportive tool for the forensic assessment of lethal erroneous transfusions and investigation of blood samples of survivors of transfusion incidents as well. Besides established morphological techniques, they allow for a certain evaluation of the pathophysiological impact of transfusion incidents as well as a diversified assessment of immunohaematologic features beyond the AB0 system.     

Application of mesocellular siliceous foams (MCF) for surface-assisted laser desorption ionization mass spectrometry (SALDI-MS) Analysis of fingermarks

Recent advances in nanotechnology applied in forensic sciences have contributed to consider new approaches including chemical evaluation of latent fingermarks. Significant improvement to the detection of small organic molecules has been reached with matrix-free methods associated to laser desorption/ionization mass spectrometry. The present study investigated the application of mesocellular siliceous foam (MCF) as an ionizing agent for laser desorption/ionization (LDI-MS) analysis of fingermarks as a proof of concept research. Fingermarks from three different donors were deposited directly onto a MALDI target plate and α-CHCA matrix solution, MCF ethanolic suspension or MCF/magnetic powder mixture were used for treatment. Microscopy characterization of MCF support showed particles with irregular morphology and variable sizes, and a unordered porous surface with pores diameter ranging from about 10 to 20?nm. Results showed less intense peaks in the spectra produced by the MCF support (control). Analysis of fingermarks showed ions related to endogenous and exogenous molecular components, including possible lipids from human sebum and quaternary ammonium cations commonly present in cosmetics. Promising and reproducible results were obtained for the fingermarks dusted with the MCF/magnetic powder mixture. Considering the forensic applications of nanomaterials for the analysis of small molecules in biological samples by matrix-free LDI techniques, the advantages of silica based materials should be further investigated.     

Cascading Bias of Initial Exposure to Information at the Crime Scene to the Subsequent Evaluation of Skeletal Remains,

Thirty‐eight participants took part in a study that investigated the potential cascading effects of initial exposure to extraneous context upon subsequent decision‐making. Participants investigated a mock crime scene, which included the excavation of clandestine burials that had a male skeletal cast dressed either in female or gender neutral clothing. This was followed by a forensic anthropological assessment of the skeletal remains, with a control group assessing the same male skeletal cast without any clothing context. The results indicated that the sex assessment was highly dependent upon the context in which participants were exposed to prior to the analysis. This was especially noticeable in the female clothing context where only one participant determined the male skeletal cast to be male. The results demonstrate the importance of understanding the role of context in forensic anthropology at an early stage of an investigation and its potential cascading effect on subsequent assessments.     

血液中乙醇检测结果的法医学分析

目的对交通事故中血液中乙醇检测结果进行法医学分析。方法从检测方法、血液采集方法、采集时间、血液保存、尸体腐败、饮酒量与血液中乙醇质量浓度关系等方面进行血液中乙醇检测结果的法医学分析。结果检测方法、血液采集方法、采集时间、血液保存、尸体腐败等因素直接影响血液中乙醇检测结果。结论为保证交通执法的公正性，对血液中乙醇检测结果应当作法医学分析。     

Comparison of the Volatile Organic Compounds from Different Biological Specimens for Profiling Potential*

Previous work has demonstrated the ability to differentiate individuals based on the analysis of human scent hand odor chemicals. In this paper, a range of forensic biological specimens are shown to also have the ability to differentiate individuals based upon the volatile organic compounds (VOCs) present. Human VOC profiles from hand odor, oral fluid, breath, blood, and urine of 31 individuals were analyzed by solid‐phase microextraction–gas chromatography–mass spectrometry (SPME‐GC‐MS) and combined methods of chromatogram comparison, Spearman rank correlation comparison, and principal component analysis. Intra‐specimen comparisons demonstrated the distinguishability of individuals above 99%. Inter‐specimen VOC profiles from the same individual were found to be too different to be used for scent‐matching purposes, with Spearman rank coefficients below 0.15. A 6‐month VOC profile monitoring of two individuals demonstrated the consistency of VOC profiles over time across specimens.     

甲醛处理后人脊髓中的利多卡因和布比卡因的同时测定

目的建立经甲醛防腐处理后人脊髓中利多卡因和布比卡因同时定量测定的HPLC分析法,以满足法医学鉴定的需要。方法以空白人脊髓经甲醛防腐处理后添加标准利多卡因和布比卡因,对样品的前处理方法及仪器测试条件、方法的线性范围、检测限、精密度、回收率进行系统考察。结果所建方法中两药物的线性范围为0.5～10.0ug.g-1(利多卡因r=0.9999;Bupivacaine r=0.9998),检测限利多卡因为15ng布比卡因为20ng,日内、日间分析的相对标准偏差均在4.3％以内,加样回收率在97.3％～100.3％之间。结论经甲醛防腐处理后的脊髓可同时进行利多卡因和布比卡因定量测定。所建方法准确、实用,适用于法医学鉴定及相关研究。     

Amphetamine, cocaine and cannabinoids use among truck drivers on the roads in the State of Sao Paulo, Brazil

Lysergic acid diethylamide (LSD) is a potent hallucinogen, active at very low dosage and its determination in body fluids in a forensic context may present some difficulties, even more so in hair. A dedicated liquid chromatography-electrospray-tandem mass spectrometry (LC-ES-MS/MS) assay in hair was used to document the case of a 24-year-old man found dead after a party. Briefly, after a decontamination step, a 50mg sample of the victim's pubic hair was cut into small pieces (<1mm length), and incubated overnight in 3mL of phosphate buffer pH 5 at room temperature. After a liquid-liquid extraction (dichloromethane/ether), the extract was analyzed using a LC-ES-MS/MS method exhibiting a limit of quantification of 0.5pg/mg for LSD. A LSD concentration of 0.66pg/mg of pubic hair was observed. However, this result remains difficult to interpret owing to the concomitant LSD presence in the victim's post mortem blood and urine, the lack of previously reported LSD concentrations in hair, and the absence of data about LSD incorporation and stability in pubic hair.     

The suitability of visual taphonomic methods for digital photographs: An experimental approach with pig carcasses in a tropical climate

In the context of increased scrutiny of the methods in forensic sciences, it is essential to ensure that the approaches used in forensic taphonomy to measure decomposition and estimate the postmortem interval are underpinned by robust evidence-based data. Digital photographs are an important source of documentation in forensic taphonomic investigations but the suitability of the current approaches for photographs, rather than real-time remains, is poorly studied which can undermine accurate forensic conclusions. The present study aimed to investigate the suitability of 2D colour digital photographs for evaluating decomposition of exposed human analogues (Sus scrofa domesticus) in a tropical savanna environment (Hawaii), using two published scoring methods; Megyesi et al., 2005 and Keough et al., 2017. It was found that there were significant differences between the real-time and photograph decomposition scores when the Megyesi et al. method was used. However, the Keough et al. method applied to photographs reflected real-time decomposition more closely and thus appears more suitable to evaluate pig decomposition from 2D photographs. The findings indicate that the type of scoring method used has a significant impact on the ability to accurately evaluate the decomposition of exposed pig carcasses from photographs. It was further identified that photographic taphonomic analysis can reach high inter-observer reproducibility. These novel findings are of significant importance for the forensic sciences as they highlight the potential for high quality photograph coverage to provide useful complementary information for the forensic taphonomic investigation. New recommendations to develop robust transparent approaches adapted to photographs in forensic taphonomy are suggested based on these findings.     

The evaluation of evidence in the forensic investigation of fire incidents (Part I): an approach using Bayesian networks

The forensic investigation of the origin and cause of a fire incident is a particularly demanding area of expertise. As the available evidence is often incomplete or vague, uncertainty is a key element. The present study is an attempt to approach this through the use of Bayesian networks, which have been found useful in assisting human reasoning in a variety of disciplines in which uncertainty plays a central role. The present paper describes the construction of a Bayesian network (BN) and its use for drawing inferences about propositions of interest, based upon a single, possibly non replicable item of evidence: detected residual quantities of a flammable liquid in fire debris.