尸僵再形成的实验性研究

目的观察尸僵再形成中肌节长度的变化。方法应用扫描电镜测定不同条件下取材的40只大鼠股四头肌肌节长度,判断再僵直的强度。结果死后未破坏的尸僵肌节的长度明显小于尸僵再形成时的长度。结论肌节长度与尸僵强度呈负相关,说明肌节长度可确定尸僵强度,从而为推断死亡时间提供依据。     

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。     

生前电击与死后电击骨骼肌肌小节的长度变化

目的研究生前电击与死后电击的肌小节长度变化,为生前电击与死后电击的鉴别提供新的方法。方法12只兔随机分为对照I组、对照II组、电击死组和死后电击组。每组3只。对照I、II组与死后电击组兔分别从耳缘静脉注射空气30m l处死。对照I组处死后,于死后即刻取其后肢股四头肌;对照II组死后24h于相同部位取材;电击死组兔通220V交流电,通电致兔死后即刻取材;死后电击组于死后即刻通220V交流电4m in后,在相同部位取材。用透射电镜观察骨骼肌肌小节长度变化,对所得结果进行统计学分析。结果生前电击与死后电击骨骼肌肌小节均缩短,与对照组I相比,前者较后者缩短程度更甚(P=0.000);死后电击组与对照I组相比,仅轻微缩短(P=0.000),对照II组相比,缩短较为明显(P=0.000);对照II组较对照I组的肌小节显著伸长(P=0.000)。结论研究骨骼肌肌小节的长度变化有助于鉴别生前电击与死后电击。     

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。     

测量大鼠死后骨骼肌pH值推断早期死亡时间实验研究

目的利用KNIpHE电极对大鼠死后不同时间骨骼肌pH值进行测定,探讨死后骨骼肌pH值与早期死亡时间(PM I)之间的关系,为利用该种电极在现场快速准确推断死亡时间取得实验依据。方法36只大鼠分为12组,每组3只,分别于死后即刻和死后1,2,3,4,6,8,10,12,16,20,24h取材,制备匀浆后,采用美国Thermo O rion公司210型便携式酸度计配套KNIpHE7120BN电极直接测量pH值;采用南京建成生物工程研究所研制的试剂盒用分光光度法检测乳酸(LA)浓度、肌酸激酶(CK)活性。结果①大鼠死后12h内,股四头肌pH值随PM I延长而逐渐下降,二者之间呈负相关;②大鼠死后12h内,股四头肌LA浓度随PM I延长而上升,与pH值呈负相关;③大鼠死后24h内,股四头肌CK活性随PM I延长而逐渐增强,二者之间呈正相关;④以12h内pH值数据对PM I进行一元线性回归分析,回归方程为:PM I=115.499-17.7pH(R2=0.662,P<0.01,R2为决定系数)。结论利用Thermo O rion KNIpHE电极测定骨骼肌pH值推断早期死亡时间具有较好的应用前景。     

鼠窒息后缺氧诱导因子1-α在心、肺中的表达

目的研究大鼠机械性窒息死亡后缺氧诱导因子1-α(HIF1-α)在心、肺中的表达变化,探讨其作为窒息死亡诊断指标的可行性。方法制作大鼠缢死模型,分别于窒息死后及正常断颈处死后0、2、6、24h时间段取材,用免疫组织化学、RT-PCR方法测定缢死后HIF1-α在心肌和肺组织中的分布和表达变化。结果HIF1-α在窒息组的心肌和肺组织中表达,窒息组和对照组在各时间段表现出明显差异,对照组仅在死后2、6、24h阳性表达。窒息死亡组可见核阳性表达,而对照组未见核阳性表达。半定量RT-PCR结果显示HIF1-α在0h时各组未见升高,但在2、6、24h窒息组则较对照组升高。结论心和肺组织HIF1-α表达核阳性细胞的出现,可以作为窒息死亡的特征性表现。     

大鼠死后视网膜细胞mRNA降解与死亡时间的关系研究

目的检测死后大鼠视网膜细胞mRNA的降解和死亡时间(PM I)的关系,为死亡时间推断提供新方法。方法应用复合荧光RT-PCR技术,检测死后不同时间(2、4、6、8、10、12、14、16、18、20、22、24、26、28h)大鼠视网膜细胞β-actin、Pgk1和Rp l 4 mRNA水平,以立即处死大鼠作为对照。方差检验比较组间差异,并对所得数据进行回归分析。结果死后28h内,大鼠视网膜细胞β-actin、Pgk1、Rp l 4 mRNA水平均随死亡时间的延长而下降。3个管家基因mRNA的降解与死亡时间的线性拟合回归方程分别为:Yβ-actin=-4436.205Xβ-actin+127581.7(r2=0.976),YPgk1=-1993.884XPgk1+57651.54(r2=0.973),YRp l 4=-1189.791XRp l 4+34533.46(r2=0.955)。结论大鼠死后视网膜细胞mRNA的含量随着死亡时间的延长而逐渐降解,与死亡时间具有相关性。     

氯胺酮在急性中毒大鼠体内的死后再分布研究

目的探索氯胺酮在大鼠体内的死后再分布变化规律及温度对再分布的影响。方法48只雄性SD大鼠随机分为2个实验组（室温组24只、冷藏组18只）和1个对照组（6只）,实验组大鼠以氯胺酮290mg／kg灌胃,45min后缺氧处死,分别置于室温（24℃）和冷藏（4℃）条件下,于死后不同时间（0、12、24、48h）取心血、外周血、肝、肺、肾、心肌、大脑,检测其中氯胺酮含量;对照组大鼠以生理盐水灌胃,各对应组织器官样品为空白对照。血和组织样品中加入内标物SKF。。后碱化,乙酸乙酯萃取,GC／MS全扫描定性,内标法、工作曲线法气相色谱定量分析。结果室温条件下,大鼠死后48h内随着死亡时间延长,心血、肺、肝中氯胺酮的浓度呈升高趋势（P〈0．05）,肾脏中氯胺酮的浓度先升高后下降（P〈0．05）,外周血、心肌和脑中氯胺酮的浓度无显著性变化（P〉0．05）。冷藏条件下,血液及组织中氯胺酮浓度变化无显著性差异（P〉0．05）,除心肌外,各样本浓度均低于相应时段室温条件保存的样本。结论氯胺酮在大鼠体内存在死后再分布现象。温度对大鼠死后血液及组织中氯胺酮浓度变化有较明显的影响。     

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。     

兔静脉空气栓塞死后不同间隔时间气体变化的初步研究

目的探讨兔静脉空气栓塞死后不同间隔时间气体变化的规律,为空气栓塞致死的法医学鉴定提供参考资料。方法建立兔静脉空气栓塞动物模型,按死后不同间隔时间分为0h、12h、1d、2d、4d、8d和16d共7组,分别从右心检测气体体积及其中CH4、CO2和N2体积百分比浓度。结果实验组均收集到气体,阴性对照组除了16d组收集到0.95ml外,均未收集到气体（V〈0.1ml）。实验组中,0h、12h和8d3组间所收集气体的差异无统计学意义（P〉0.05）,1d和2d两组之间右心气体体积的差异无统计学意义（P〉0.05）,其它各组两两之间均存在统计学差异（P〈0.05）。实验组检测气体体积呈先下降后上升趋势,CO2浓度上下波动,气体成分均符合典型空气栓塞气体成分标准;16d对照组气体接近于腐败气体。结论兔静脉空气栓塞气体体积在死后16d内呈先轻微下降后上升的规律;静脉空气栓塞死后8d内检测结果准确、可靠,而8~16d的检测结果需结合其他证据综合分析,才能确定是否为静脉空气栓塞致死。     

Experimental evaluation of rigor mortis. VII. Effect of ante- and post-mortem electrocution on the evolution of rigor mortis

The influence of electrocution on the evolution of rigor mortis was studied on rats. Our experiments showed that: (1) Electrocution hastens the onset of rigor mortis. After an electrocution of 90 s, a complete rigor develops already 1 h post-mortem (p.m.) compared to 5 h p.m. for the controls. (2) Electrocution hastens the passing of rigor mortis. After an electrocution of 90 s, the first significant decrease occurs at 3 h p.m. (8 h p.m. in the controls). (3) These modifications in rigor mortis evolution are less pronounced in the limbs not directly touched by the electric current. (4) In case of post-mortem electrocution, the changes are slightly less pronounced, the resistance is higher and the absorbed energy is lower as compared with the ante-mortem electrocution cases. The results are completed by two practical observations on human electrocution cases.     

Determination of Adenosine Phosphates in Rat Gastrocnemius at Various Postmortem Intervals Using High Performance Liquid Chromatography

Abstract: Although the change in adenosine phosphate levels in muscles may contribute to the development of rigor mortis, the relationship between their levels and the onset and development of rigor mortis has not been well elucidated. In the current study, levels of the adenosine phosphates including adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) in gastrocnemius at various postmortem intervals of 180 rats from different death modes were detected by high performance liquid chromatography. The results showed that the levels of ATP and ADP significantly decreased along with the postmortem period of rats from different death mode whereas the AMP level remained the same. In addition, it was found that changes in the ATP levels in muscles after death correlated well with the development of rigor mortis. Therefore, the ATP level could serve as a reference parameter for the deduction of rigor mortis in forensic science.     

Estimation of the breaking of rigor mortis by myotonometry

Myotonometry was used to detect breaking of rigor mortis. The myotonometer is a new instrument which measures the decaying oscillations of a muscle after a brief mechanical impact. The method gives two numerical parameters for rigor mortis, namely the period and decrement of the oscillations, both of which depend on the time period elapsed after death. In the case of breaking the rigor mortis by muscle lengthening, both the oscillation period and decrement decreased, whereas, shortening the muscle caused the opposite changes. Fourteen h after breaking the stiffness characteristics of the right and left m. biceps brachii, or oscillation periods, were assimilated. However, the values for decrement of the muscle, reflecting the dissipation of mechanical energy, maintained their differences.     

Postmortem metabolic indices of antemortem adrenergic stimulation

Tissue lactate concentration has been reported to be a useful postmortem indicator of antemortem awareness of mortal danger. The purpose of this study was to determine further whether selected tissue metabolites could be used as postmortem markers of antemortem adrenergic stress. Sprague-Dawley albino rats were anesthetized with pentobarbital and then injected with 2.0 mg kg-1 i.p. epinephrine hydrochloride to induce experimentally a severe sympathetic response that may be associated with the awareness of mortal danger; 20 min after the injection of epinephrine, when the metabolic response was at its peak, the animals were killed by exsanguination. Samples of the following tissues were removed immediately prior to death (0 h) and 48 h postmortem: soleus, plantaris, kidney medulla, kidney cortex, liver, and heart. These samples were analyzed for glycogen, lactate, ATP, creatine phosphate, pH, and total protein concentration. Significant differences in lactate concentration were observed in all tissues except soleus at 0 h in the epinephrine-injected animals. Specific tissues also had significant reductions in glycogen, ATP, and creatine phosphate concentrations at 0 h. At 48 h postmortem, however, only the liver and soleus lactate concentrations were significantly different from the 48-h control samples. It is unlikely that these small differences found in some tissues at 48 h postmortem would be detected in an uncontrolled accident situation. We concluded from these findings that these selected tissue metabolites are not useful as long-term postmortem indicators of antemortem adrenergically induced hypermetabolism.     

Long persistence of rigor mortis at constant low temperature

We studied the persistence of rigor mortis by using physical manipulation. We tested the mobility of the knee on 146 corpses kept under refrigeration at Torino's city mortuary at a constant temperature of +4 degrees C. We found a persistence of complete rigor lasting for 10 days in all the cadavers we kept under observation; and in one case, rigor lasted for 16 days. Between the 11th and the 17th days, a progressively increasing number of corpses showed a change from complete into partial rigor (characterized by partial bending of the articulation). After the 17th day, all the remaining corpses showed partial rigor and in the two cadavers that were kept under observation "à outrance" we found the absolute resolution of rigor mortis occurred on the 28th day. Our results prove that it is possible to find a persistence of rigor mortis that is much longer than the expected when environmental conditions resemble average outdoor winter temperatures in temperate zones. Therefore, this datum must be considered when a corpse is found in those environmental conditions so that when estimating the time of death, we are not misled by the long persistence of rigor mortis.     

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。     

Factors and circumstances influencing the development of hemorrhages in livor mortis

Petechial hemorrhages or ecchymoses in the skin of the face and/or in eyelids and/or conjunctivae are one important feature in postmortem diagnosis of lethal strangulation. On the other hand, petechial bleedings can occur in various causes of death, especially in cases of neck or thoracic compression, they can occur in acute cardiac failure, as a result of blood or skin diseases or as a postmortem phenomenon. The focus of this investigation (retrospective study of 279 corpses, found initially in a prone position or some other face down position) was to analyse the frequency of postmortem (hypostatic) hemorrhages and factors which may influence their development. Petechial hemorrhages in livor mortis in the skin of the trunk and extremities were found in 110 cases (39%). The frequency ranged from 41% in the side position and 44% in the kneeling position to 50% in the prone position. Increasing intensity of livor mortis resulted in an increasing frequency of hemorrhages, up to 59%. In cases with a body-mass-index (BMI) of more than 26 the frequency of hemorrhages increased up to 64%. In cases without livor mortis when the corpses were found as well as in cases with complete movement of livor mortis after turning the corpses, no hemorrhages were found. If hypostasis was partly or completely fixed, the rate of hemorrhages increased up to 50%, without additional increase in longer postmortem intervals. Obviously postmortem petechiae develop neither very soon nor days after death, but within a period of several hours after death.