Perimortem or Postmortem Bone Fractures? An Experimental Study of Fracture Patterns in Deer Femora*

The determination of perimortem trauma is important for forensic anthropologists. Characteristics of bone fractures such as sharp edges, presence of fracture lines, the shape of the broken ends, fracture surface morphology, fracture angle on the Z-axis, and butterfly fractures are said to differentiate perimortem from postmortem trauma. A Drop Weight Impact Test Machine was used to break 76 deer femora of various ages since death. The results of this study suggest that the characteristics listed above are unreliable at differentiating a perimortem fracture from a postmortem fracture in a forensic case. There are, however, statistically significant differences between fresh bones broken less than 4 days old and dry bones broken 44 days or 1 year old after death.     

Generalized additive models and Lucilia sericata growth: assessing confidence intervals and error rates in forensic entomology

Forensic entomologists use blow fly development to estimate a postmortem interval. Although accurate, fly age estimates can be imprecise for older developmental stages and no standard means of assigning confidence intervals exists. Presented here is a method for modeling growth of the forensically important blow fly Lucilia sericata, using generalized additive models (GAMs). Eighteen GAMs were created to predict the extent of juvenile fly development, encompassing developmental stage, length, weight, strain, and temperature data, collected from 2559 individuals. All measures were informative, explaining up to 92.6% of the deviance in the data, though strain and temperature exerted negligible influences. Predictions made with an independent data set allowed for a subsequent examination of error. Estimates using length and developmental stage were within 5% of true development percent during the feeding portion of the larval life cycle, while predictions for postfeeding third instars were less precise, but within expected error.     

尸源性昆虫的法医学研究进展

尸源性昆虫学是应用昆虫学知识解决有关法律问题的法医学分支学科,对死亡时间的推断。特别是腐败尸体的死后间隔时间的推断等方面具有无可比拟的优越性。本文根据国内外近期法医昆虫学方面的研究进展,阐述了尸源性昆虫的研究历史、种类和侵蚀过程,并总结了尸源性昆虫形态学及分子生物学的种属鉴定方法。及近几年来在推断死亡时间方面的具体应用。就尸源性昆虫在法医学领域内的应用及进展进行综述。     

死亡人体组织中rRNA亚基的稳定性及影响因素评价

目的探讨人尸体组织中rRNA亚基表达水平的稳定性及影响因素。方法选取3例成人、3例婴幼儿大脑皮质和脾组织,在尸检即刻、48、72、96、120、144、168、192、216、240h,采用实时荧光定量RT-PCR法检测5s、5.8s、18s、28s rRNA的表达水平。结果两个年龄组两种组织中4种rRNA亚基表达量相比较均显示有差异(P0.05)。同种组织比较:脑组织中两个年龄组最后一个时间点与第一时间点4种rRNA亚基的表达量均有差异(P0.05),其他各时间点与第一时间点无显著性差异(P0.05);脾组织中婴幼儿5s rRNA在最后一个时间点,其余3种rRNA亚基最后两个时间点与第一时间点比较有差异(P0.05);成人5s rRNA最后一个时间点,5.8s rRNA亚基最后两个时间与第一时间点比较差异(P0.05),其余两种亚基各时间点与第一时间点相比较均无差异(P0.05)。结论尸体组织中rRNA亚基表达稳定性好,适于作为晚期死亡时间推断的内参基因使用,但需注意指标、组织和年龄段差异性。     

不同环境条件下大鼠死后皮肤生物力学特性改变

目的死亡时间的推测是法医病理学研究的重点和难点。皮肤具有一定生物力学特性,是机体死后分解破坏发生较迟的部分。本研究观察不同环境条件下死后大鼠皮肤生物力学特性的改变,探索其与死亡时间的关系。方法系统测试雌性SD大鼠在不同环境条件下（A组较高环境温度,B组较低环境温度）的死后皮肤生物力学特性。结果 A组大鼠皮肤死后张应力、延伸率在死后1d内先降低后升高,1d～6d逐渐降低,6d～7d略呈上升趋势;B组大鼠皮肤死后张应力在死后2d内先降低后升高,2d～16d逐渐降低,16d～20d略上升。结论 A组的张应力、延伸率和B组的张应力、应变能密度均表现出与死亡时间较好的相关性,是较好的推测死亡时间的生物力学参数。     

Investigation of Postmortem Absorption and Redistribution After the Application of a Fentanyl Patch

Fentanyl deaths have increased with availability of transdermal patches. Interpretation of postmortem fentanyl levels may be complicated by postmortem redistribution and absorption of fentanyl from a patch. We applied an unused 100‐μg/h fentanyl patch onto the lower abdomen of a decedent with no premortem fentanyl exposure. Ocular fluid, blood, and urine were collected prior to placement, and the decedent was refrigerated for 23 h. Prior to the autopsy, urine, subcutaneous tissue under the patch, and samples from the same anatomic sites were obtained. We observed no fentanyl in any postpatch placement samples (LOD: 0.1 ng/mL for blood and vitreous fluid, 1.0 ng/mL urine, 2.0 ng/g for tissues). Although we observed no postmortem absorption of fentanyl, this was only a single case; therefore, we recommend that patches be removed after receipt of a cadaver before initiation of an autopsy, with the location of removed patch documented.     

The Potential of High-throughput Metagenomic Sequencing of Aquatic Bacterial Communities to Estimate the Postmortem Submersion Interval

Human remains can be discovered in freshwater or marine ecosystems, circumstances where insects and other invertebrates have infrequently been used for understanding the time of postmortem submersion. In this study, the identification and succession of epinecrotic bacterial communities on vertebrate remains were described during decomposition in a temperate headwater stream during two seasons (summer and winter). Bacterial communities were characterized with 454 pyrosequencing and analyzed at phyletic and generic taxonomic resolutions. There was a significant increase in genera richness over decomposition during both seasons. Additionally, multivariate statistical modeling revealed significant differences in bacterial communities between seasons at both taxonomic resolutions and siginificant genera differences among sampling days within each season, suggesting a succession of these communities. These data are the first to describe aquatic bacterial succession using high-throughput metagenomic sequencing on vertebrate remains submerged in a freshwater habitat, and provide initial evidence for their potential use in forensic investigations.     

氯胺酮在家兔死后体内的弥散研究

目的研究氯胺酮在大白兔体内死后弥散过程和再分布机制。方法 48只实验大白兔随机分为8组,采用缺氧处死后以150mg/kg氯胺酮灌胃,尸体仰卧位于室温下放置;在0~96h内分8个时间点各解剖1组,提取体液和脏器组织样品;采用GC/MS法定性结合GC-NPD法定量检测样品中氯胺酮含量,并计算心血/外周血中氯胺酮含量的比值。结果大白兔死后氯胺酮灌胃尸体放置96h内,脑、尿液、玻璃体液、左上/下肢肌肉样本中均未检测到氯胺酮,心血、外周血、心肌、脾、肾、肝、肺、胆汁中氯胺酮含量随死后时间呈动态升高的变化;其中距离胃较近的组织(如脾)较早检测到含量较高的氯胺酮,而距离较远的组织或体液中氯胺酮含量较低且较晚检测到;心血/外周血中氯胺酮含量比值为1.73。结论氯胺酮在家兔体内存在死后再分布,从胃到器官组织、心血顺浓度梯度弥散是主要机制。脑、玻璃体液、尿液、肢体肌肉不受死后弥散的影响,可作为生前服毒与死后染毒氯胺酮的鉴别依据。     

ABC法检测血小板颗粒膜蛋白鉴别生前伤与死后伤

甲抗人血小板α-颗粒膜蛋白140（GMP－140）单克隆抗体，ABC免疫组化方法鉴别生前伤与死后伤．生前皮肤切创和刺创标本创缘上见条状褐色反应带，死后皮肤切创标本创线上未见上述反应带。该法可用于检测短时期发生的生前伤与死后伤。     

2633例机械性窒息法医尸检资料回顾性研究

本文根据湖北省部分地区1957～1986年间尸检记录,收集并分析了2633例机械性窒息死的出现率、案情性质、城市与乡村的差别等问题,为法医学实践提供了可供参考的资料。