死后血液流动对氯胺酮在家兔尸体内再分布的影响

目的观察分析静脉注射氯胺酮家兔死后血液流动对体内药物浓度再分布影响。方法雄性新西兰大白兔随机分为实验组2组（各24只）,对照组（8只）;实验组家兔经耳缘静脉注入40mg/kg氯胺酮,1.5h后处死,其中一组立即结扎主动脉,另一组不结扎;家兔尸体仰卧位室温下保存,分别于死后0、3、6、12、24、48、72和96h解剖并采取组织和体液样本;对照组静脉注射等量生理盐水,同样方法解剖取相同样本。所有样本采用GC/MS和GC-NPD法检测样品中氯胺酮含量。结果两个实验组家兔尸体放置96h内氯胺酮含量,除尿液各时间点与0h以及相邻时间点之间比较均有显著性差异（P〈0.05）外,两组家兔其余各类样本与0h以及相邻时间点比较均无显著性差异（P〉0.05）。除尿液外,各类样本两个实验组之间均无显著性差异（P〉0.05）;结扎组和不结扎组心血与外周血中氯胺酮含量比值分别为0.90~1.03和0.90~1.02。结论静脉注射氯胺酮家兔死后的血液流动不是体内氯胺酮发生再分布的主要机制。     

PCR-DHPLC法检测硅藻SSU基因在溺死鉴定中的应用

目的采用PCR-DHPLC法检测硅藻SSU基因,评估其在溺死鉴定中的应用价值。方法 60只实验兔随机分为生前溺死（水中溺毙）、死后入水（空气栓塞致死后入水）、对照组（空气栓塞致死后不做处理）;溺死人体脏器组织;取各组织检材提取硅藻DNA,PCR扩增硅藻特异的核糖体小亚基（SSU）片段,用琼脂糖凝胶电泳检测、DHPLC检测分析。结果 6份硝酸消化法检测阴性的溺死人体器官组织检材经PCR及琼脂糖凝胶电泳检出5例阳性。生前溺死组肺、肝、肾硅藻检出率分别为100%、90%、85%,死后入水组仅肺检出硅藻（15%）,对照组各组织均为阴性;生前溺死组检出率明显高于死后入水组（P〈0.05）。10份溺死人体器官组织检材采用DHPLC法检出硅藻种类明显多于微波消解-扫描电镜法（P〈0.05）。脏器检出硅藻种类与溺死点水样一致。结论采用PCR-DHPLC法检测硅藻SSU基因,有助于溺死鉴定和溺死地点的推断,具有法医学应用价值。     

不同死因大鼠死后不同时间红细胞溶血速度比较

目的观察不同死亡原因大鼠尸体血液中红细胞溶血速度的变化规律,为死亡原因的法医学推断提供新思路。方法 40只SD大鼠随机分为4组,分别以断髓、置于99%CO的空间、高坠、勒颈方式处死后,取各组大鼠右心室血液,于死后即刻（0h）、8h、16h、24h、32h、40h、48h、56h、64h、72h,采用显微镜数码图像法进行全血红细胞计数（CBC）,并对组内和组间数据进行统计学比较分析。结果 4组血液红细胞数量在死后即刻至72h期间,均随时间的延长因溶血而减少。其中0~16h,各组溶血速度无明显差异（P〉0.05）;16~48h,速度加快,溶血速度以CO中毒组（88.50±25.99）%最快,其次为高坠（69.33±29.52）%和断髓组（48.78±3.17）%,机械性窒息组（41.90±9.61）%最慢,组间比较具有显著性差异（P〈0.05）;56h后,溶血速度再次减慢,至72h机械性窒息组仍有少量红细胞存在。结论 4组不同死因大鼠死后不同时间红细胞计数均减少,各组间差异具有统计学意义,其变化特征可为死亡原因的推断提供新的思路。     

宁波甬江水域夏冬季节溺死兔内脏硅藻16SrDNA的鉴定

目的采用PCR法检测夏季7月和冬季12月宁波甬江水域溺死家兔内脏组织中硅藻16SrDNA,评估其在夏季7月和冬季12月溺死鉴定中的应用价值。方法于夏季7月和冬季12月分别选取30只大白兔,总计60只大白兔,随机分为溺死组(n=10)、死后入水组(n=10)、空气栓塞组(n=10)。各组分别提取心、肝、肺、肾组织,应用PCR技术检测上述兔内脏硅藻16SrDNA。结果与死后入水组比较,夏季7月兔溺死组心、肝、肺、肾组织中硅藻16SrDNA检出率明显增高(P<0.05);而冬季12月溺死组仅心、肺组织中检见硅藻16SrDNA,与死后入水组比较无明显差异(P>0.05);夏季7月溺死兔组心、肝、肺、肾组织中硅藻16SrDNA检出率明显高于冬季季12月溺死兔组(P<0.05);夏季7月和冬季12月空气栓塞组心、肝、肺、肾组织中硅藻16SrDNA均未检出。结论宁波甬江水域夏季溺死兔中硅藻16SrDNA检出率高,PCR技术可用于溺死诊断;而冬季硅藻16SrDNA检出率低,运用该技术诊断溺死应慎重。     

无电流斑电击死兔骨骼肌il-6mRNA表达研究

目的探讨生前电击与死后电击的鉴别方法及电流通路的推断方法。方法15只新西兰兔，随机分为3组，每组5只，即电击死组、死后电击组、对照组。电击死组，用220V交流电的两极分别连接实验动物的左后肢与右前肢，通电致死。死后电击组，从耳缘静脉注射50ml空气致死，于死后即刻用220V交流电的两极分别连接实验动物的左后肢与右前肢通电3min。对照组直接从耳缘静脉注射50ml空气致死，不进行电击。用荧光RT—PCR技术检测骨骼肌白介素6信使核糖核酸（il-6mRNA）表达水平，所得结果进行统计学分析。结果电击死兔骨骼肌il-6mRNA水平远高于死后即刻电击者（P〈0．05）；电击死兔对称肢体中通电肢体骨骼肌il-6mRNA水平远高于非通电肢体（P〈0．05）。结论骨骼肌il-6mRNA表达变化可用于生前电击与死后电击的鉴别；机体对称部位骨骼肌il-6mRNA表达差异有助于推断电流通路。     

家兔死后的角膜厚度变化及其与死亡时间的关系

目的探讨家兔死后不同时间角膜厚度变化及其与死亡时间的关系。方法将25只家兔采用空气栓塞的方法处死后,用角膜超声测厚仪分别于死后即刻、2h、4h、8h、12h和24h测量角膜的厚度,所得数据进行统计学处理。结果即刻死亡家兔角膜厚度平均值为（357.10±6.41）μm,死亡24h角膜厚度平均增加（187.52±11.38）μm;4h内,眼睑开启与闭合对角膜厚度的增加无明显影响（F=3.5290,P〉0.05）,8h后随时间延长,眼睑闭合角膜厚度为（429.24±8.80）μm,明显超过眼睑开启角膜平均厚度（421.40±9.53）μm,其差异有显著性意义（F=14.4480,P〈0.05）。眼睑闭合的角膜厚度与死亡时间关系为y=8.2418x＋357.33（相关系数r1=0.8732）;眼睑开启的角膜厚度与死亡时间关系为y=7.3737x＋357.23（r2=0.8578）。结论在一定条件下,家兔死后24h内角膜厚度与死亡时间呈线性相关。     

常规冷冻对大鼠尸体组织形态学的影响

目的观察分析死后不同时间冷冻大鼠尸体主要内脏组织细胞形态变化规律。方法 SD大鼠20只,分为尸僵前冷冻组、尸僵期冷冻组、尸僵缓解冷冻组及对照组（各5只）,颈椎脱臼处死大鼠,实验组大鼠在室温25℃±5℃、相对湿度80%±5%分别放置0h、6h、24h后-20℃±2℃冰箱冷冻72h,解剖提取脑、心、肺、肝、肾,常规切片HE染色,显微图像体视学测量细胞外间隙的面密度。结果各实验组内脏组织间质疏松增宽,冰晶裂隙沿组织间隙或肝血窦分布、周边细胞固缩,红细胞冻溶、血管周围浆液淤积,以肝组织变化最明显。细胞外间隙的面密度：对照组明显小于实验组（P〈0.01）;脑尸僵前组较尸僵组大（P〈0.05）;心、肾尸僵前组和尸僵组无显著差异（P〉0.05）,均较尸僵缓解组大（P〈0.01）;肝各实验组组间比较均无显著差异（P〉0.05）。结论冷冻不同尸僵状态下内脏组织细胞有不同的形态结构,可作为区别和判断生前和死后组织细胞形态改变的参考。     

Caspase3和iNOS在人挫伤脑组织中的时序性表达

目的研究人脑挫伤后不同时间半胱氨酸天冬氨酸蛋白酶3（caspase3）和诱导型一氧化氮合酶（inducible nitric oxide synthase,iNOS）表达的变化,为法医实践中脑损伤时间的推断提供依据。方法选择30例因颅脑损伤死亡案例为损伤组,5例非颅脑损伤急死的案例为对照组,应用免疫组织化学和图像分析技术,分别于死亡后2h、4～8h、10～14h、1～2d、3～5d及8～11d检测脑组织标本中caspase3和iNOS的变化规律。结果经统计学分析：（1）caspase3阳性细胞表达在伤后2h以内组开始升高,与对照组相比差异有统计学意义（P〈0.05）,1～2d组表达强度增高,3～5d组仍见高表达（P〈0.05）,以后逐渐下降。（2）iNOS阳性细胞表达在2h以内组与对照组比较差异无统计学意义（P〉0.05）,伤后4～8h开始升高（P〈0.05）,1～2d组表达强度最高,以后逐渐下降,伤后8～11d仍有弱表达（P〈0.05）。结论caspase3和iNOS的表达可能成为实际检案中脑损伤时间推断的有效依据。     

兔皮肤钝器伤IL-1β、COX-2和MCP-1 mRNA表达与法医学应用

目的应用荧光定量PCR技术检测兔皮肤钝器伤后IL-1β、COX-2和MCP-1mRNA的时序性表达规律,分析其与损伤时间的关系。方法分别在兔耳皮肤钝器伤后<0.5h,0.5h,1h,2h,3h,4h,5h,6h,8h,12h,24h,1d,3d,7d和死后10min,0.5h,1h取材,一步法提取组织总RNA,逆转录合成cDNA第一条链,荧光定量PCR检测IL-1β、COX-2和MCP-1mRNA逆转录合成第一条cDNA链的拷贝数,作统计学分析。结果IL-1βmRNA在钝器伤后<0.5h表达显著增强(P<0.001),0.5h达到峰值,至第2d降至基本水平;COX-2mRNA于创伤后0.5h表达显著增强(P<0.05)并持续强表达至24h开始下降,第2d降至正常;MCP-1 mRNA在钝器伤后于1h表达显著增强(P<0.05),于3h出现表达峰,至第3d降至正常;3个指标在死后各时间组与正常对照无明显表达差异。结论检测皮肤IL-1β、COX-2和MCP-1mRNA可对早期损伤时间的推断提供帮助,并且这三个指标都可以鉴别生前伤和死后伤。     

兔死后角膜厚度与死亡时间的关系

目的研究兔死后角膜厚度变化规律与死亡时间(postmortem interval,PMI)的关系。方法用空气栓塞法建立兔死亡模型。在兔死后0~72h,每隔6h进行角膜取材,切片后常规HE染色,用光学显微镜摄取全角膜图像,结合Motic Images Plus 2.0图像分析软件观察角膜上皮层厚度(x1)、角膜基质层厚度(x2)、全角膜厚度(x3)3项指标的变化值,并作统计学分析,建立与PMI(y)的回归方程。结果在兔死后72 h内,角膜基质层厚度和全角膜厚度均在死后12h开始增加,并在死后54h达到高峰,两者与PMI正相关,回归方程分别为y=-0.070 2 x22+11.398 x2+1 634(R2=0.712 2,P0.05),y=-0.074 9 x32+12.036 x3+1 819.4(R2=0.675 0,P0.05)。结论角膜基质层厚度和全角膜厚度与PMI之间呈较好的线性关系,且角膜基质层厚度优于全角膜厚度,可作为推断死亡时间的指标。     

利用房水钾离子浓度推断死亡时间的实验研究

目的探讨利用房水中钾离子浓度进行死亡时间推断的可行性。方法30只家兔随机分为10组,以空气栓塞法处死后,于不同的死亡时间点分别采集房水和玻璃体;用Vitros 950干式自动生化仪对所有样本中的K+、Na+、Ca2+三种离子进行浓度测定;用SPSS统计软件对测定数据进行回归分析。结果房水中钾离子浓度变化与死亡时间呈高度相关,对应的回归方程为:PMI=1.572-0.597×[K+]+0.107×[K+]2-0.002×[K+]3。其相关系数(R2=0.95)明显高于同批样本的玻璃体钾离子浓度与死亡时间的相关系数(R2=0.5)。房水、玻璃体液的Na+、Ca2+浓度与死亡时间的相关性不明显。结论利用房水钾离子浓度推断死亡时间可获得较好的准确度。     

Air embolism or putrefaction? Gas analysis findings and their interpretation

Gas was detected in the hearts of 111 necropsy cases. The gas was quantified and then analyzed by gas chromatography. In 70 cases H2, a clear marker of putrefaction, could be identified in the samples. After critical consideration, air embolism was accepted in 36 of the remaining cases. In nearly all instances, severe skull trauma or stab wounds to the neck or clavicular region gave rise to the air embolism. When the gas analysis data were compared, clear-cut differences were found between the two groups of putrefaction and air embolism. CO2 concentrations below 15%, N2 concentrations above 70%, and a CO2/N2 ratio below 0.2 proved to be good criteria to determine an air embolism. However, gas volumes, O2 concentrations, and CO2/O2 ratios largely overlapped in the two groups. Air embolism samples consistently had lower O2 concentrations and higher CO2 concentrations than atmospheric air, and this was evidently independent from incipient putrefaction. We suggest that these deviations result from a gas exchange between the venous blood and the embolized air volume taking place in the right heart ventricle. The dimensions of the concentration shifts may be understood from severe agonal hypoxia and hypercapnia.     

家兔死后眼玻璃体液锌、镍含量与 PMI关系的研究

目的寻找一种精确推定PMI的方法。方法应用电感耦合等离子体质谱（ICP－MS）,检测了家兔死后96小时内眼玻璃体液锌、镍元素含量,探讨其与PMI的相关性。结果家兔死后24h内眼玻璃体液锌、镍元素含量与PMI显著相关,可作为推定早期PMI的参考指标,其二项式回归方程分别为y=0.1404x2－1.3351x＋3.8298（R2=0.9202）、y=0.0043x2－0.0596x＋0.2665（R2=0.9103）。结论家兔眼玻璃体液中Zn、Ni元素含量变化是推定早期PMI的参考指标之一。     

家兔死后眼玻璃体液镁，铁含量与PMI关系的研究

目的寻找一种精确推定PMI的方法。方法应用电感耦合等离子体质谱(ICP-MS),检测家兔死后96h内眼玻璃体液镁、铁元素含量,探讨其与PMI的相关性。结果家兔死后0～48h眼玻璃体液镁元素含量与PMI显著相关,6～48h铁元素含量与PMI显著相关,其二项式回归方程分别为y=0.0738x2+0.6997x+11.45(R2=0.9119)、y=0.0411x2-0.3148x+1.4113(R2=0.9594)。结论家兔死后眼玻璃体液Mg、Fe含量变化可作为推定48h内PMI的参考指标之一。     

Venous air embolism in homicidal blunt impact head trauma. Case reports

From 1992 through 1997, there were 41 deaths by homicidal blunt impact head trauma in Hillsborough County, Florida. Twenty-one cases were excluded from the study because of putrefaction or survival beyond the emergency department doors, leaving 20 cases for the study. One of the 15 nonputrefied victims found dead at the scene and 1 of the 5 victims pronounced dead in the emergency department had definite venous air embolism. Victim 1 was found dead, bludgeoned with a concrete block, and had open vault and comminuted basilar skull fractures. The dura forming the right sigmoid sinus at the jugular foramen was lacerated. A preautopsy chest radiograph and examination under water documented gas in the pulmonary artery and right ventricle. Victim 2 was bludgeoned with a steel stake and was pronounced dead on arrival in the emergency department. He had open comminuted vault fractures, a transverse basilar skull fracture, and lacerations of the brain. Direct examination and preautopsy chest radiography revealed air in the right side of the heart. A third victim, with basilar fractures, had a small gas bubble in the pulmonary artery not detected by the case pathologist. A fourth victim, with a basilar skull fracture, had an unusual radiographic finding that was thought to be air in the posteromedial aspect of the lower lobe of the left lung but could not be excluded as an air embolus. Optimal postmortem documentation of venous air embolism includes the demonstration of the embolus and the site of air ingress. This study demonstrates that venous air embolism occurs in some victims of homicidal bludgeoning and suggests that when significant, it is easily demonstrated in the absence of putrefactive gas formation. The presence of venous air embolism can serve as evidence that a victim was alive and breathing at the time of the infliction of head wounds. In the belief that venous air embolism might be underdiagnosed in many medical examiner offices, the authors have sought to bring attention to the entity by publishing their experience with it in cases of bludgeoning.     

Gas embolism as a cause of death

Systemic venous gas embolism other than that due to air is a great rarity. A case is reported and the criteria for the diagnosis are discussed. The clinical similarities between embolism of systemic venous air and that of systemic venous gas are emphasized. The two conditions can be differentiated by laboratory investigation only.     

大鼠死后管家基因mRNA稳定性及其时序性降解与PMI相关性研究

目的研究脑组织及骨骼肌内β-actin、GAPDH、RPL32、PKG1、SDHA、RPL13、HPRT、TBP、YWHAZ死后稳定性及其相对表达量与死亡时间(PMI)的相关性。方法取健康成年SD大鼠33只,依据据死亡时间不同随机分为11组(0h、1h、3h、6h、12h、24h、2d、4d、8d、16d、24d),分别在各时间点取大鼠胫骨前肌及脑组织约50mg,提取各组织总RNA,利用RT-q PCR技术检测9种管家基因的m RNA相对表达量。运用ge Norm、Norm Finder和Best Keeper软件对基因稳定性进行评价,利用spss软件对内参标准化的m RNA指标进行回归分析。结果脑组织及骨骼肌中均为HPRT稳定性最高,适合用于本研究的内参基因。脑组织中SDHA、RPL32及TBP 3种指标的相对表达量变化与PMI有一定的线性关系。骨骼肌中m RNA指标相对表达量与PMI之间没有显著的相关性。结论脑组织及骨骼肌是较适宜推断晚期死亡时间的检材。脑组织中SDHA、RPL32及TBP 3种m RNA的相对表达量变化与PMI有一定的线性关系,有望成为推断PMI的辅助指标。     

新西兰白兔死亡后颅脑CT检查与死亡时间关系的研究

目的采用CT扫描动态观察新西兰白兔死亡后脑组织变化,建立利用CT值、脑组织/颅腔面积比,推断死亡时间(PM I)的研究方法。方法通过耳缘静脉注射空气,建立新西兰白兔死亡模型;于死亡后0~120h,运用CT进行头颅平描;选取颅顶面层测定脑组织CT值、脑组织/颅腔面积比。结果死亡后兔脑组织CT值呈双峰样上升、脑组织/颅腔面积比呈不断下降趋势;建立与死亡时间的回归方程:CT值=47.4780-0.1768T+0.0049T2(T/h,CT值/HU)、面积比=99.7368+0.3098T-0.0118T2/100(T/h)。结论CT扫描检查可准确显示兔脑的死后变化;脑组织消失之前,综合运用CT检查指标可用于准确推断死亡时间。     

Infant death due to air embolism from peripheral venous infusion

An otherwise healthy male infant was brought to the hospital because the mother suspected superficial infection at the operative site 5 days after an inguinal hernia repair. He was admitted to the pediatric unit overnight to be evaluated by his surgeon the next morning. When a venous infusion of maintenance fluids was started, the patient immediately went into cardio-respiratory arrest and was pronounced dead after resuscitation efforts failed. Subsequently, air collections were found in both venous and arterial circulations, including the splenoportal system. Detailed review of the clinical presentation and course, laboratory results, radiological, and pathological findings, along with a review of pertinent literature provides an explanation for the death by air embolism. Apparent inconsistent findings both radiographically and at autopsy are resolved. The mechanism of distribution of air to both systemic and splenoportal circulation is discussed. We believe this to be only the eighth case reported in English-language literature of infantile death from peripheral venous infusion. In all age groups, we find only six other cases in the English-language literature of gas found concomitantly in both the systemic and portal venous systems.     

Time-related changes in cardiac ct images of rabbits died from four kinds of execution

Objective To explore the feasibility and appropriate parameters for estimating postmortem interval (PMI) through time-related CT imaging into dynamically monitoring the cardiac changes of rabbits died from four kinds of execution. Methods The experimental rabbits were executed with four disposals of air embolism, strangulation, drowning and hemorrhagic shock. The dead rabbits were observed of their hearts with CT scanning every 6 hours within 120h from the death moment, having the obtained time-different CT images and mean CT values examined. With the cardiac average CT values of rabbits died from discrepant execution, four relevant regression equations were established against the elapsing time (i.e. PMI). Results The CT images of post-death cardiac tissue of rabbits died from one of four executions did change regularly with the PMI elongating, showing consistent with the autopsy verification. The binomial regressive equations were established between the post-death cardiac average CT value and PMI from four executions, demonstrating statistically significant (P<0.05). Conclusion The postmortem cardiac CT imaging into PMI analysis, plus the relating regression equation, provides a new objective visual quantitative approach and reference for forensic medicine to infer the time of death. © 2021, Editorial Office of Forensic Science and Technology. All rights reserved.