The Effects of Soil Environment on Postmortem Interval: A Macroscopic Analysis

Abstract:  Burial environment, in particular soil moisture, has a significant impact on the type, rate, and extent of bone degradation, which ultimately affects estimations of the postmortem interval (PMI). The purpose of this research is to determine the effects of soil moisture on the color, weight, condition, and texture of bone as it relates to the PMI. Bone changes occurring over two different time intervals (2 and 5 months) were examined using 120 sus scrofa leg bones. During each time interval bones were buried in two soil environments, one of which was drier than the other. The bones in both environments lost weight over time but the net weight loss was greater for bones in the higher moisture environment. There was no change in color, texture, or overall condition, indicating that 150 days is not long enough for such alterations to occur, regardless of the moisture level of the burial environment.     

Estimating the Time of Death in Domestic Canines

Abstract:  Because 36.1% of U.S. households have dogs, the time of death (TOD) of dogs at crime scenes can be useful to forensic investigators. However, there are few published studies based on postmortem changes in dogs. This study, conducted indoors in still air at approximately room temperature, monitored the postmortem reduction in rectal, liver, brain, and aural temperatures in 16 dogs for 32 h after death. Graphs of temperature reduction were prepared to estimate the TOD of dogs within the first 32 h postmortem. Sex, body mass, and hair coat density did not affect the rate of body temperature reduction, but increased body weight and volume slowed it. Rectal temperature was the most convenient, reasonable site for measuring body temperature. Vitreous humor potassium ion concentration [K⁺] was measured in both eyes at c.  1.5 and 7 h after death. Both eyes had the same [K⁺] when measured simultaneously, and [K⁺] increased after death.     

Forensic Imaging‐Guided Recovery of Nuclear DNA from the Spinal Cord*,†

Abstract: Our objective is to document the recovery of DNA from the spinal cord or surrounding dura mater in 11 cases of severely burned human remains. Radiographs established that portions of charred tissue contained spine segments. Multidetector computed tomography (MDCT) revealed that each spine specimen contained an intact spinal cord remnant. A full DNA profile was obtained from seven specimens using spinal cord dura mater in six specimens and spinal cord medulla in one specimen. A partial profile was obtained from four specimens (spinal cord dura mater, 2; spinal cord medulla, 2). Bone and muscle surrounding the spinal cord appear to insulate nucleic acid containing tissue from critical thermal degradation. The spinal cord, which is easily identified by MDCT examination of remains and easily recovered at the postmortem examination, can be a source of DNA with extraction yields comparable with other tissue sources. Specimens of dura mater are preferable as processing time is faster than bone.     

利多卡因在蛛网膜下腔和静脉注射致死犬体内的死后分布

目的比较利多卡因在蛛网膜下腔和静脉注射致死犬体内的死后分布特点。方法犬12只,其中6只经蛛网膜下腔,另6只经股静脉匀速注入利多卡因(5×15mg/kg)致死,迅速解剖动物,取大脑、侧脑室脑脊液、腰段脊髓腔脑脊液、不同脊髓节段(颈髓、胸髓、腰髓、骶髓),心、肺、肝、脾、肾、胆汁、尿、心血、周围血、注射部位肌肉和注射部位20 cm以外肌肉等脏器组织和体液,用气质联用法定性,气相色谱法定量检测其中利多卡因含量。结果蛛网膜下腔注射致死犬体内利多卡因的含量由高到低顺序依次为腰段脊髓腔脑脊液、骶段脊髓、胸段脊髓、侧脑室脑脊液、腰段脊髓、颈段脊髓、肺、肾、注射部位肌肉、心、大脑、脾、心血、肝、周围血、胆汁、注射部位20 cm以外的肌肉、尿;静脉注射致死犬体内利多卡因的含量由高到低顺序依次为肾、心、肺、脾、大脑、肝、周围血、胆汁、心血、颈段脊髓、胸段脑脊液、注射部位肌肉、腰段脊髓、注射部位20 cm以外的肌肉、侧脑室脑脊液、尿、腰段脊髓腔脑脊液、骶段脊髓。结论蛛网膜下腔注射致死犬背侧脊髓液中利多卡因含量最高,静脉注射致死犬肾脏利多卡因含量最高,此分布特征可为利多卡因麻醉意外法医学鉴定中入体途径的判定提供参考。     

大鼠死后肋软骨细胞核DNA含量随死亡时间的变化

目的研究大鼠死后肋软骨细胞核DNA含量与晚期死亡时间的相关性。方法应用改良的Feu lgen法结合计算机图像分析技术对死后大鼠35d内肋软骨细胞核DNA含量变化进行观测分析。结果死后1~28d,细胞核染色逐渐变淡,至35d时已观察不到,死后肋软骨细胞核DNA含量与死亡时间呈直线相关。结论大鼠肋软骨细胞核DNA含量随死亡时间延长呈线性规律下降。     

曲马多在家兔体内的死后分布研究

目的研究曲马多在中毒家兔体内死后分布规律,为曲马多中毒检材采取提供实验依据。方法家兔经口给予10倍LD50曲马多,待家兔死亡后迅速解剖取样,气相色谱／质谱联用和气相色谱-FTD法测定其体液、脏器、大脑及右上肢和右下肢肌肉中曲马多的含量,比较其变化规律。结果血液和肝脏中曲马多的最低检出限分别为0．05μg/mL和0．05μg/g,提取回收率为97．60％±0．65％～103．10％±1．24％。曲马多在家兔体内的死后分布为：肾〉胃〉肝〉脾〉肺〉脑〉心〉上肢肌肉〉下肢肌肉〉〉体液（尿〉胆汁、心血〉玻璃体液）。结论大剂量曲马多中毒致死后在体内分布不均匀,组织中曲马多含量明显高于心血、胆汁等体液。     

针刺干预无先兆偏头痛患者的弥散张量成像研究

目的 通过弥散张量成像（diffusion tensor imaging,DTI）技术和纤维束自动定量分析（automated fiber quantification,AFQ）方法探讨无先兆偏头痛患者在针刺干预前后脑白质纤维的变化。方法 纳入无先兆偏头痛患者20例和健康受试者10例,无先兆偏头痛患者进行每周3次、连续4周的针刺干预,干预前后分别进行DTI和T1像扫描,健康受试者不针刺,仅进行1次核磁扫描。比较无先兆偏头痛患者针刺前后以及无先兆偏头痛患者和健康受试者基于AFQ方法的各向异性分数（fractional anisotropy,FA）值。结果 与健康受试者比较,无先兆偏头痛患者右皮质脊髓束、右上纵束部分节点FA值显著减弱（P＜0.05）;与针刺前比较,无先兆偏头痛患者头痛天数及头痛程度显著下降（P＜0.05）,头痛频率下降不显著,无先兆偏头痛患者右皮质脊髓束、右上纵束、左扣带回部分节点FA值显著增强（P＜0.05）。结论 无先兆偏头痛患者存在广泛白质纤维束受损,针刺能促进受损的脑白质纤维恢复。     

磁敏感加权成像在出血性弥散性轴索损伤鉴定中的应用

目的探讨磁敏感加权成像(susceptibility weighted imaging,SWI)在出血性弥散性轴索损伤(diffuse axonal injury,DAI)法医学鉴定中的应用价值。方法对20例DAI的法医学鉴定资料进行回顾性分析,对其T1WI、T2WI、扩散加权成像(diffusion weighted imaging,DWI)、液体衰减反转恢复(fluid attenuated inversion recovery,FLAIR)、磁敏感加权成像(susceptibility weighted imaging,SWI)序列影像资料进行统计分析。结果 DAI出血灶多位于脑组织表浅区,SWI对出血性DAI的检出率最高,与其他序列成像之间的差异有统计学意义(P0.05)。结论 SWI在DAI法医学鉴定中具有重要的意义。     

The influence of site of collection on postmortem morphine concentrations in heroin overdose victims

When assaying for postmortem morphine concentration, significant site sampling variability exists between central and peripheral sampling sites and even within sampling regions of the body. To study the variation, 76 suspected heroin overdoses were identified. Each had femoral artery (FA) and vein (FV), left and right ventricle and pooled heart blood samples obtained at autopsy. Forty-four tested positive for morphine. Morphine concentrations were determined by gas chromatography/mass spectrometry, with sampling site differences reported as log-transformed ratios and compared by signed rank test.The mean FA to FV ratio for total morphine was 1.2 (range 0-4.5). The ratio for left heart to right heart total morphine was 1.1 (range 0.4-3.2). Left ventricular to FV total morphine ratio was 2.0 (range 0.6-6.9). In these opioid overdose deaths, FA and FV morphine concentrations are usually similar, although up to 4.5-fold differences were noted. Centrally obtained morphine concentrations are on average twice as high compared with peripheral morphine concentrations. Left and right ventricular morphine concentrations were usually similar, although up to 3.2-fold differences were noted (left side higher).     

早期心肌梗死死后诊断的法医病理学研究进展

心源性猝死在成人猝死的死因中占首位,心肌梗死是冠心病猝死的主要机制之一,由于早期心肌梗死发生突然,且可在短时间内死亡,肉眼和镜下都缺乏典型的形态学改变,一直都是法医实践中研究的热点,本文回顾多年来心肌梗死的研究成果在法医学中的应用及局限,展望新的临床指标在法医工作中的可行性,期望提高死后心肌梗死诊断的准确率。