利用猪胸主动脉生物力学性能时序性变化推断死亡时间

目的观察分析家猪尸体胸主动脉生物力学性状指标的变化规律,探讨其在死亡时间(PMI)推断中的应用价值。方法采集180根家猪的主动脉,在恒定温度、湿度下,于2～230h之间每间隔12h设置1个取检材时间点组;各组主动脉检材用电子万能材料试验机拉伸检测极限载荷、极限载荷变形、平均力、应力、应变,宽度和厚度等生物力学参数指标;应用多元逐步回归方法进行统计学分析。结果家猪死后230h内,随PMI延长,胸主动脉大体观呈自溶腐败性变色、瘫软、液化趋势。生物力学参数指标中,极限载荷、平均力和应力呈随PMI延长呈明显下降趋势,PMI间隔24h组间比较差异性均有统计学意义(P<0.05),校正决定系数分别为0.923、0.806、0.867,估计标准误差分别为±18.39h、±29.88h、±24.58h,PMI间隔24h组间比较差异性均有统计学意义(P<0.05),其它指标与PMI之间相关性不显著均P>0.05。结论死后230h内家猪胸主动脉的极限载荷、平均力和应力的死后时序性变化,与PMI呈明显的负相关性,可用于PMI推断,其中极限载荷效果最佳。     

硬脑膜厚度及生物力学参数时序性变化在死亡时间推断中的应用

目的研究人尸体硬脑膜厚度以及生物力学参数与死亡时间(postmortem interval,PMI)的关系,探讨其用于推断PMI的可行性。方法收集尸体检验的硬脑膜样本并按死后6h、12h、18h、24h、30h、36h、48h、60h、72h、84h、96h分组,统一制作成4.0cm×1.0cm的A、B两块试件。测量A试件厚度后检测极限载荷、最大力变形、抗拉强度、弹性模量、断裂力等生物力学参数,分别拟合厚度和生物力学参数值与PMI的回归方程,并通过验证组验证PMI预测值与实际值之间的差异。B试件经10%中性甲醛溶液固定后制备组织切片观察其形态学变化。结果死后6~96h,硬脑膜厚度逐渐减小,胶原纤维从排列清晰逐渐变为相互融合,细胞核数量逐渐变少;硬脑膜厚度、极限载荷、抗拉强度、弹性模量、断裂力呈时序性下降趋势,其中硬脑膜厚度、极限载荷、弹性模量、断裂力与PMI具有相关性(P<0.05)。回代检验中验证组PMI实际值和预测值之间差异无统计学意义(P>0.05)。结论人死后6~96 h的硬脑膜厚度、极限载荷、弹性模量、断裂力呈时序性变化,利用其与PMI的关系建立的回归方程可用于PMI推断。     

大鼠死后肌肉总腺苷酸及腺苷酸能荷的时序性变化

目的测定大鼠死后不同时间双后肢肌肉嘌呤腺苷酸[三磷酸腺苷(adenosine triphosphate,ATP)、二磷酸腺苷(adenosine diphosphate,ADP)、一磷酸腺苷(adenosine monophosphate,AMP)]含量,计算总腺苷酸(total adenine nucleotide,TAN)含量和腺苷酸能荷(adenylic-acid energy charge,AEC)的变化值并探究其与死亡时间(postmortem interval,PMI)的关系。方法健康大鼠颈部脱臼处死后,20℃恒温保存,分别于死后0、24、48、72、96、120、144、168 h提取大鼠双后肢肌肉,利用反相高效液相色谱法测定嘌呤腺苷酸含量,计算双后肢肌肉组织的TAN和AEC,并分别建立其与PMI关系的相关回归方程。结果大鼠死亡168h内,ATP、ADP变化趋势不同,AMP的含量持续增加;TAN值随PMI的延长而逐渐增加,而AEC在死后168h内,整体呈现下降趋势。AEC随PMI变化规律明显,决定系数较高(R2为0.903),曲线拟合关系较好;ATP、ADP、AMP、TAN与PMI拟合关系不佳(R2为0.198~0.754)。结论AEC的死后变化规律为法医学PMI推断提供了新的研究思路。     

金刚烷胺在大鼠体内的死后再分布研究

目的 建立金刚烷胺的死后再分布动物模型,研究其在大鼠体内的死后再分布规律,为金刚烷胺相关案件的法医学鉴定提供实验依据。方法 126只雄性SD大鼠,随机分为3组（L组、M组、H组）,按治疗极量、LD50和2LD50灌胃,未死的按照LD50平均死亡时间处死,仰卧位置于20℃条件下,按照0 h、6 h、12 h、24 h、48 h、72 h、96 h采集心血、外周血、心、肝、脾、肺、肾、脑、肌肉、睾丸并检测金刚烷胺的含量。结果 治疗极量的金刚烷胺入体后,在心血、心、肝中的含量在死后6 h前下降随后上升,在脾、肾、脑、肌肉和睾丸组织中的含量在死后48 h前都较为稳定,并于96 h点达到峰值,但在肺脏中的含量随时间呈现逐渐下降的趋势;LD50剂量的金刚烷胺入体后,在各组织中的含量均在死后24 h前有下降趋势,随后上升,在外周血、脾、肾、肌肉中的含量于死后48 h点达到峰值,在心血和睾丸中的含量于72 h点达到峰值,在肝、肺、脑中的含量于96 h点达到峰值;2LD50剂量的金刚烷胺入体后,在心、肝中的含量在死后12 h前有下降趋势,在肺、脑、肌肉中的含量在死后48 h前均有下降趋势,在心脏、肝、脾...     

大鼠脑挫伤后脑C-FOS、AQP-4表达与损伤时间的关系

目的观察大鼠脑挫伤组织周围C-FOS、AQP-4表达的时序性变化规律,分析评价其在脑挫伤时间推断中的价值。方法采用自由落体撞击法建立SD大鼠开放性脑挫伤模型,于伤后0~168h不同时间点取挫伤区脑组织,应用HE染色及免疫组织化学染色方法,结合图像分析及统计学技术进行分析,并与假手术组和正常对照组进行比较。结果大鼠脑挫伤后0~168h时间内脑皮质挫伤区内C-FOS、AQP-4的表达随损伤时间的变化呈明显的时序性变化,C-FOS阳性表达于伤后12h、AQP-4阳性表达于伤后72h分别达高峰。根据实验组各时间点IOD值,分别建立根据C-FOS、AQP-4表达推断损伤时间的回归方程。结论脑挫伤部位C-FOS和AQP-4的表达规律在脑挫伤时间推断中有潜在的应用价值。     

大鼠脾细胞DNA含量与早期死亡时间关系的图像分析研究

选择15只大鼠 ,处死后 ,在24h内每隔1h进行脾细胞学涂片、福尔马林液固定、Feulgen染色后 ,用自动图像分析仪测量细胞DNA的积分光密度、平均光密度、异形指数等指标 ,并对数据进行统计学处理。实验结果证明大鼠脾细胞DNA含量在死后24h内 ,随死亡时间的延长而呈较有规律的下降。其中积分光密度、平均光密度、异形指数是用来研究死亡24h内脾DNA降解规律 ,并准确推断死亡时间的较好指标     

大鼠死后肌动蛋白降解与死亡时间的相关性

目的观察大鼠死后不同时间心肌、肝、脾、肺、肾、脑和骨骼肌肌动蛋白（actin）的降解规律,为晚期死亡时间（postmortem interval,PMI）的推断寻找客观指标。方法28只SD大鼠随机分为7组,经机械性窒息致死后．分别置于20℃恒温箱内,于0、24、48、72、96、120和168h后剖取以上器官,应用免疫印迹技术检测各组织内actin的含量,SPSS11．5软件对所得数据进行方差分析。结果大鼠死后上述各器官actin含量均随PMI的延长而逐渐下降,与PMI相关,决定系数（R2）均在0．75以上。但actin在上述各器官内的降解速度有显著差异（P〈O．05）,在脑组织中降解速度最快,其余依次为肺、脾、肝、肾、心肌和骨骼肌。结论尽管大鼠死后心肌、肝、脾、肺、肾、脑和骨骼肌actin的降解规律具有组织差异性,但是actin在上述组织中的含量变化与PMI相关．有助于较晚期PMI的推断。     

FTIR光谱结合数据挖掘方法构建死亡时间推断数学模型

目的利用傅里叶变换红外(Fourier transform infrared,FTIR)光谱技术结合数据挖掘方法分析死后大鼠脾组织FTIR光谱与死亡时间的关系,推断大鼠死亡时间。方法大鼠脱臼处死,尸体置于20℃环境中,于不同时间点取大鼠脾组织,采集FTIR检测数据,数据预处理后应用数据挖掘方法进行分析。结果大鼠脾组织光谱吸收峰强随死亡时间延长发生变化,峰位没有改变;主成分分析结果示前三个主成分累积贡献率为96%,各时间点光谱样本具有明显聚类趋势;偏最小二乘判别分析和支持向量机分类方法可将不同死亡时间光谱样本进行有效四分类(0~24h、48~72h、96~120h和144~168h);偏最小二乘回归分析构建的死亡时间推断模型决定系数(R~2)为0.96,校正均方根误差和交叉验证均方根误差分别为9.90h和11.39h,预测集R~2达到0.97,预测均方根误差为10.49h。结论 FTIR光谱技术结合数据挖掘方法可对大鼠脾组织进行有效定性和定量分析,可建立分类判别和偏最小二乘回归模型,对死亡时间进行准确推断。     

大鼠尸体细菌演替规律及其在死亡时间推断中的应用(英文)

目的探讨大鼠尸体细菌演替规律并评估其在死亡时间(PMI)推断中的应用价值。方法选取成年雌性SD大鼠,处死后置于纸箱内自然腐败,采集大鼠眼周皮肤、口腔和阴道三个部位的细菌样本,使用纯培养生化方法鉴定菌种,记录菌群构成变化规律。结果大鼠三个部位细菌演替规律显示,葡萄球菌属和奈瑟菌属为死后初期的优势菌属,尤其是金黄色葡萄球菌与乳糖奈瑟菌在死后6 h内相对含量较高。干酪乳杆菌规律地出现在死后第3或第4天,且在死后晚期维持较恒定水平。结论大鼠死后三个部位的正常细菌及腐败细菌呈现一定的演替规律,可用于PMI推断。     

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。     

Nontraumatic clostridial myonecrosis.

We describe three cases of nontraumatic clostridial myonecrosis seen at the Victorian Institute of Forensic Medicine. Nontraumatic clostridial myonecrosis is an uncommon and often fatal condition that requires immediate institution of appropriate medical and surgical therapy. It is most commonly caused by Clostridium perfringens and Clostridium septicum and is associated with gastrointestinal and hematologic malignancies, diabetes mellitus, and peripheral vascular disease. The clinical features include a rapidly evolving acute illness with severe pain, marked tachycardia, and brawny discoloration of the skin with bullae formation and crepitus, followed by hypotension and acute renal failure. Features at autopsy include reddish brown skin discoloration with bullae formation and necrotic skeletal muscle. Radiographs may be of use prior to the postmortem in detecting gas within the soft tissues. Gram stain and microbiologic culture are important in establishing a definitive diagnosis; although the major factors in suggesting the diagnosis are the recognition of the typical clinical history and macroscopic autopsy findings.     

Drugs in postmortem adipose tissues: evidence of antemortem deposition

INTRODUCTION: Drug concentration measured in postmortem adipose tissue may or may not reflect antemortem concentration. To examine the possibility of whether the presence of basic drugs in adipose tissue is the result of postmortem change, we examined: tissues with and without livor mortis, concentration gradients within the adipose layer, and the stability of drug concentrations during the postmortem period. CASE REPORTS: Five drug-related deaths with case histories and analytical data are presented. Adipose tissues with and without livor mortis from the thigh area of the same decedent were analyzed for cocaine. The cocaine concentration of the tissue exhibiting 4+ livor was equivalent to the concentration observed in tissue without livor. Analyses of cross sections of adipose tissues containing cocaine and methamphetamine disclosed that drug concentrations were equally distributed throughout the layer, from just beneath the dermis to directly above the muscle. When morphine and temazepam concentrations were measured in adipose tissues collected from similar sites, but at different times, from the same cadaver, they remained essentially the same over 3 days (approximately 80 h). CONCLUSIONS: Since concentrations were the same in areas with and without livor mortis, the possibility of redistribution into adipose from blood or vascular channels is eliminated. The absence of a concentration gradient within the adipose layer rules out diffusion or permeation from muscle into the adipose layer, and the failure of morphine or temazepam concentration to change over time indicates that drugs in the adipose tissue are stable during the postmortem interval. Our findings support the notion that drugs identified in postmortem adipose tissue are there because of antemortem deposition and not because of any postmortem change or event.     

死后不同时间大鼠心肌膈肌β肌动蛋白mRNA的检测

目的探讨死后不同时间心肌和膈肌β肌动蛋白mRNA(β-actin mRNA)的降解变化。方法大鼠断颈处死后置于21℃的温度控制系统,采用RT-PCR技术检测大鼠心肌和膈肌组织-βactin mRNA在死后即刻至12d的变化,并对电泳图像进行半定量分析。结果在死后即刻,以及保存2,4,6,8,10,12d的大鼠心肌组织样本中均可检测到β-actin mRNA,而膈肌组织仅在死后即刻和保存2,4,6d的样本中检测到-βactin mRNA;-βactin mRNA的扩增产物在死后12d内呈下降趋势。结论RT-PCR技术检测大鼠心肌和膈肌组织中的β-actin mRNA,其在死后12d内的降解呈现一定规律。     

大鼠死后心肌和肺脏微管蛋白降解规律的初探研究

目的探讨大鼠死后心肌和肺脏微管蛋白（tubulin）的降解规律与死亡时间（PMI）的关系。方法大鼠经切断股动脉致失血性休克处死后，置于RXZ智能型人工气候箱内，实验条件设定为：20℃恒温，湿度50％。分别于大鼠死后0、1、2、3、5和7d时剖取心肌和肺脏组织，应用Western-Blot法检测心肌和肺脏tubulin的含量，并对所得数据进行统计学分析。结果Tubulin在正常大鼠心肌和肺内高表达，死后1d时其含量已开始下降，至死后7d时仍可检测到微管蛋白的存在，但tubulin在肺脏内的降解速度快于心肌。两种组织内tubulin含量随PMI变化的回归方程及相关系数分别为：心肌Y=-1726．Ix＋14083，r=0．9684；肺脏Y=-1439．89x＋12041，r=0．9808。结论大鼠死后心肌和肺脏tubulin的含量逐渐减少，与PMI具有相关性。     

Dielectric parameters of the tissues as additional criteria of postmortem period duration in medical examination of dismembered corpses

We studied dielectric indices of soft tissues from the parts of the dismembered corpses (skin, fragments of head, trunk extremities muscles) in terms of postmortem period duration. True (epsilon/) and false (epsilon//) parts of dielectric permeability at 10 cm wave length were determined. We obtained the curves characterizing changes in tissue dielectric parameters for 30 days after death. Thus, biophysical parameters of dismembered coupse fragments allow precise dating of death.     

Determination of Malathion levels and its effect on the development of Chrysomya megacephala (Fabricius) in South China

The present study determines the concentration of Malathion in rabbit tissues and Dipteral larvae feeding on those tissues. Malathion was found in all muscle and liver samples of the test rabbit, as well as larvae fed on it. Samples from the control rabbit and pupae from all colonies were negative for Malathion. Correlations were found between administered dosage, tissue concentrations and younger or prepuparial larvae. Effects of Malathion on the development rate of Chrysomya megacephala (Fabricius) were also reported. C. megacephala is the most common fly species found on corpses in South China during the early stages of decomposition. Significant differences in larval growth rate were both observed among the colonies fed on muscle and liver. The presence of Malathion in both muscle and liver appears to retard the normal growth rate of C. megacephala in larval stage. Larvae from all colonies fed on tissues from rabbits treated with Malathion were smaller and attained maximum length later than those from the control colony. Duration of the larval and pupal stages was both significantly prolonged for larvae on tissues from rabbit receiving Malathion than those from the control colony. The difference of the duration of the larval and pupal stages together from the muscle colonies would alter the postmortem interval estimation by up to 36 h. As for liver colonies, it would alter the postmortem interval estimation by up to 28 h. A significantly different duration of the larval and pupal stages from the muscle colonies would alter a postmortem estimate by up to 28 h relative to the liver colonies.     

Virtopsy hemorrhage of the posterior cricoarytenoid muscle by blunt force to the neck in postmortem multislice computed tomography and magnetic resonance imaging

In forensic autopsies, one of the most important and common signs of violence to the neck is hemorrhages of the soft tissues. The Institute of Forensic Medicine in Bern evaluates the usefulness of postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) of forensic cases prior to autopsy. The aim of this study was to prove the sensitivity of postmortem MSCT and MRI in the detection of hemorrhages of the neck muscles. A full body scan prior to and a detailed scan of the explanted larynx after autopsy were performed. MSCT detected multiple fractures of the larynx. Detailed MRI was able to demonstrate the hemorrhage of the left posterior cricoarytenoid muscle. The minor hemorrhage of the right posterior cricoarytenoid muscle could not be detected with certainty. Although more experience is required, we conclude that combined MRI and MSCT examination is a useful tool for documentation and examination of neck muscle hemorrhages in forensic cases.     

Changes in the amount of prostaglandin F2 alpha in incision wounds of the skin with different time intervals after injury

A radioimmunological method is presented for the determination of the quantity of prostaglandin F2 alpha in cut wounds on the skin of guinea pigs. Rapidly increasing quantities of prostaglandin F2 alpha can be found in skin cuts, and the level reaches 71 ng/g within the 1st hour after the injury. In the postmortem period, the quantities calculated in the cuts while the animals were still alive gradually decreased and reached a value of 17 ng/g in the 6th h after death. In postmortem cuts, inflicted in the 8th h after death, the prostaglandin was 14-18 ng/g. In later postmortem cuts the quantity was about 9-10 ng/g. Establishing the dynamics of the quantitative changes permits investigation of the prostaglandin to be used to certify whether the victim was alive or not, as well as when the skin damage was inflicted.