A novel method for cyanide quantification in human whole blood using ion chromatography with amperometric detection and its application to cyanide intoxication cases

Cyanide is a highly toxic agent that has been frequently used for suicide in South Korea. It is also used in various industrial fields, such as metal plating, in which many accidental cyanide intoxications have occurred. To overcome the disadvantages of conventional cyanide analysis methods, a simple and fast method for the analysis of cyanide in whole blood using ion chromatography (IC) with amperometric detection was developed in this study. Whole blood samples were deproteinized, diluted, and analyzed using an IC–amperometric detection system. The limits of detection and quantitation were 0.1 and 0.2 mg/L, respectively. The method showed good linearity in the range of 0.2 to 50 mg/L with R² > 0.99. The intra- and inter-assay precision and accuracy values were <10%. The established method was successfully applied to analyze whole blood samples from three cyanide intoxication cases.     

甲维盐中毒死亡小鼠体内的分布及死后再分布

目的研究甲氨基阿维菌素苯甲酸盐(简称甲维盐)中毒死亡小鼠的致死血浓度、靶器官组织、毒物蓄积库和死后毒物再分布的特征。方法采用灌胃法建立中毒小鼠模型,动态观察急性中毒组、亚急性中毒组小鼠的主要中毒症状和临床死亡时间。观察中毒死后小鼠各器官组织病理形态学改变,应用酶联免疫吸附试验测定死后0、24、48、72h甲维盐体内分布及死后再分布,采用高效液相色谱法测定中毒小鼠的致死血浓度和死后各时间点的血中甲维盐浓度。结果中毒小鼠均在灌胃后15~30 min内依次出现神经、呼吸系统症状。急性中毒组小鼠的临床死亡时间为(45.8±7.9)min,亚急性中毒组为(8.0±1.4)d。甲维盐的急性致死血浓度范围为447.164 0~524.463 5 mg/L。光镜及荧光显微镜下各器官组织均见明显的病理改变;小鼠中毒死后72 h内,血、心、肝、脾、肺、肾及脑甲维盐浓度变化具有规律性(P0.05)。结论甲维盐中毒作用的主要靶器官为心、肝、肾、肺、脑和接触部位(胃),其主要蓄积库为肾、肝,甲维盐在小鼠体内存在死后再分布现象。     

死后眼组织变化与死亡时间推断

眼组织推断死亡时间一直是国内外法医学界的研究热点之一,从肉眼观到镜下观,从细胞水平到分子水平,不断有新的研究成果和报告出现。大量研究资料表明,随着死亡时间的延长,眼角膜、视网膜、玻璃体液及房水等均出现规律性的变化,并与死亡时间高度相关,可用于死亡时间推断。本文对其在法医学领域的研究进展作以综述。     

山羊支气管肺炎的计算机断层扫描影像研究

为了研究山羊支气管肺炎的计算机断层扫描(CT)影像表现,将10只山羊随机分为2组。试验组、对照组各5只,试验组通过气管内注射血清A型多杀性巴氏杆菌标准菌(4×10^8CFU/mL)人工诱发山羊的支气管肺炎,对照组注射等体积无菌PBS;观察接种前、后各组山羊的临床症状、体温及全血白细胞数等指标,并同时在接种前和接种后第1、3、5天对胸部进行CT扫描,比较两组影像学差异,观察山羊肺部病理解剖学变化。结果显示:接种前后体温、全血白细胞数差异显著;对照组CT影像接种前后未见异常;试验组影像多见两侧肺叶中下部呈现大小不等的片状或结节状的类似软组织密度影,边缘不清,肺纹理紊乱且模糊,支气管壁增粗,支气管扩张,呈"树芽征"及"轨道征"。结果表明,经气管内接种巴氏杆菌能够成功诱发支气管肺炎,CT影像与山羊支气管肺炎的临床表现密切相关,对山羊支气管肺炎的诊断具有较好的敏感度,有利于鉴别,应成为其较早期诊断的依据之一。     

Postmortem chest computed tomography for the diagnosis of drowning:a feasibility study

It may be difficult to distinguish the cause of death in drowning cases without specific findings. The aim of this study was to explore the forensic value of thoracic postmortem computed tomography (PMCT) using routine images and three-dimensional (3D) image reconstructions. The imaging data of PMCT examinations of six drowning cadavers, aged 21–54 years, were analyzed. Twelve victims of sudden death from coronary artery disease (CAD) were chosen as a control group. After 3D bilateral lung images were reconstructed using image processing software, an interactive medical image control system was used to measure and analyze parameters including lung volume, lung volume ratio, mean CT value of the whole lung, and lung CT value distribution curves. Lung volume and lung volume ratio were used to assess the shape changes of the lung. Lung CT value distribution curves showed the corresponding number of pixels of the different CT values in the lung image. Lung volume was not significantly larger in drowning cases (mean 2 958 cm³) than in controls (mean 2 342 cm³). Lung volume ratio values in the drowning group (mean 0.3156) were greater than those in the control group (mean 0.2763); (P = 0.02). There was no significant difference between the drowning and control group in the mean CT value of the whole lung. There were differences between lung CT value distribution curves in drowning victims and controls, with drowning victims showing a single peak and CAD cases showing a bimodal distribution. Thoracic PMCT is helpful for the forensic medical diagnosis of drowning. Lung volume ratio and lung CT value distribution are potential indicators to distinguish between drowning and CAD.     

Volatile Organic Compound Profiling from Postmortem Microbes using Gas Chromatography–Mass Spectrometry

Volatile organic compounds (VOCs) are by-products of cadaveric decomposition and are responsible for the odor associated with decomposing remains. The direct link between VOC production and individual postmortem microbes has not been well characterized experimentally. The purpose of this study was to profile VOCs released from three postmortem bacterial isolates (Bacillus subtilis, Ignatzschineria indica, I. ureiclastica) using solid-phase microextraction arrow (SPME Arrow) and gas chromatography–mass spectrometry (GC-MS). Species were inoculated in headspace vials on Standard Nutrient Agar and monitored over 5 days at 24°C. Each species exhibited a different VOC profile that included common decomposition VOCs. VOCs exhibited upward or downward temporal trends over time. Ignatzschineria indica produced a large amount of dimethyldisulfide. Other compounds of interest included alcohols, aldehydes, aromatics, and ketones. This provides foundational data to link decomposition odor with specific postmortem microbes to improve understanding of underlying mechanisms for decomposition VOC production.     

Evaluating Bioinformatic Pipeline Performance for Forensic Microbiome Analysis*,†,‡

Microbial communities have potential evidential utility for forensic applications. However, bioinformatic analysis of high-throughput sequencing data varies widely among laboratories. These differences can potentially affect microbial community composition and downstream analyses. To illustrate the importance of standardizing methodology, we compared analyses of postmortem microbiome samples using several bioinformatic pipelines, varying minimum library size or minimum number of sequences per sample, and sample size. Using the same input sequence data, we found that three open-source bioinformatic pipelines, MG-RAST, mothur, and QIIME2, had significant differences in relative abundance, alpha-diversity, and beta-diversity, despite the same input data. Increasing minimum library size and sample size increased the number of low-abundant and infrequent taxa detected. Our results show that bioinformatic pipeline and parameter choice affect results in important ways. Given the growing potential application of forensic microbiology to the criminal justice system, continued research on standardizing computational methodology will be important for downstream applications.     

Unusual and Fatal Case of an Undiagnosed Intravascular Large B-cell Lymphoma: The Oncologist’s Great Imitator†

Intravascular lymphoma (IVL) is a rare subtype of extranodal lymphomas that is characterized by the selective growth of neoplastic cells within the lumen of small vessels. Authors document the case of an unexpected death caused by an undiagnosed intravascular large B-cell lymphoma with multi-organ involvement, which had initially manifested as an infection and then as an unclarified central nervous system pathology. Histological examination showed a diffuse intravascular large B-cell brain lymphoma with prominent cerebral involvement. The relevance of the case report reveals the importance of an autopsy of an extremely rare and threatening pathology that in most cases is diagnosed only postmortem. As a result, the role of the forensic pathologist becomes particularly important. When specifically performing an in-depth autopsy evaluation with a specific histologic analysis, it is possible to identify the intravascular lymphoma and declare a more accurate cause of death.     

Postmortem Changes of Female External Genitalia and Their Importance in Suspected Sexual Abuse

Examination of the female external genitalia to assess for sexual abuse is performed in living individuals, and the interpretation of the findings is based on evidence-based studies. However, in the deceased, no such studies are available, and postmortem changes could present as suspicious findings that can be mistaken for trauma. Patches of discoloration in the hymen were reported previously in one case as hypostasis (i.e., livor and lividity), and based on this finding, it was listed as a finding that is not associated with trauma. This was a retrospective study that was conducted in the Center of Forensic and Legal Medicine in Dammam, Saudi Arabia over a 4-year period. The study included 30 deceased women in whom photographic documentation of their external genitalia was assessed for postmortem changes. The postmortem interval ranged from less than 24 h to more than 100 days, and the ages of these deceased women were in the 20–40 year-old age group. In cases where the hymen, vagina, and/or fossa navicularis were clearly visible, none of these areas showed any hypostatic discoloration. A comparison between antemortem and postmortem appearance of the hymen in one case clearly showed the absence of hypostatic changes in the hymen. In conclusion, any discoloration of the external genitalia that is detected in a female decedent requires serious consideration.