Estimation of postmortem interval based on the third component of complement (C3) cleavage

To estimate postmortem interval (PMI), the spontaneous conversion of the native third component of complement (C3) to its derived fragments in whole blood was studied by crossed immunoelectrophoresis. C3 cleavages in vitro at different temperatures showed that the incubation of whole blood at a higher temperature led to a faster conversion of beta 1C (native C3) to beta 1A (C3c). In cadaveric blood, we found a significant positive correlation between percentage of C3 cleavage and PMI. From these results, it is possible to estimate PMI from the ratios of C3 cleavage.     

根据C_3转化率和尸体肛温推断死亡时间

本文观察了不同温度条件下,人血中C_3转化率的变化情况。在14个尸解案例中,根据C_3转化率和尸体肛温推断死亡时间,其95％可信区间为±11小时。测定C_3转化率的同时,还可以观察C_3的表型,为无名尸体的个人识别提供依据。     

兔死后角膜内皮细胞核DNA降解随死亡时间变化规律

目的研究兔死后角膜内皮细胞核DNA降解与死亡时间的关系。方法应用单细胞凝胶电泳(SCGE)技术结合荧光显微镜和专业的计算机图像分析技术,检测27只家兔死后48h内不同时间点角膜内皮细胞核DNA降解情况。结果家兔死后角膜内皮细胞产生彗星现象,彗星样细胞出现率于兔死后6h开始逐渐增加。死后6～18h彗星样细胞出现率增加缓慢,死后24～36h出现率上升较快;死后36～48h彗星样细胞出现率上升缓慢,但仍始终保持在较高的水平上(M185.4%),其回归方程为y=-0.0096x2+2.4548x+5.7964,与死亡时间呈正相关(R2=0.9743)。结论家兔死后角膜内皮细胞彗星样细胞出现率随死亡时间增加而逐渐增加。     

Estimation of postmortem interval. Temperature-correction of extracellular abdominal impedance during the first 21 days of death

Extracellular impedance of the intact abdomen of rats increased from 79.0+/-7.4Omega, 1h postmortem (i.e. 0.04 day), to 130.5+/-14.4Omega at postmortem interval (PMI)=1 day. Impedance then decreased with time, reaching 64.2+/-9.9Omega at PMI=21 days. The time taken for mean abdominal impedance to decrease below the value at PMI=0.04 day averaged 16 days. It is therefore impossible, using extracellular abdominal impedance alone, to distinguish (in terms of interpolating PMI) between numerically equal impedances on the rising and falling phases of curves depicting impedance as a function of PMI.Correction of measured impedances to their theoretically-predicted values at an arbitrarily chosen temperature of 40 degrees C appreciably diminished the magnitude of the increase in impedance following death. Thus, temperature-corrected abdominal impedance increased from 56.2+/-4.8Omega at PMI=0.04 day to 59.5+/-6.2Omega at PMI=1 day. Impedance then decreased, reaching 29.2+/-4.1Omega at PMI=21 days. The time taken for mean, temperature-corrected abdominal impedance to decrease below the value at PMI=0.04 day averaged 3 days (as opposed to 16 days (see above) in the absence of temperature-correction).These findings are believed to improve the usefulness of extracellular abdominal impedance as a potential tool for estimation of postmortem interval.     

家兔急性有机磷中毒死后玻璃体液化学成分的变化趋势

目的 探讨家兔急性有机磷中毒死后不同时间眼玻璃体液化学成分的变化。方法用5％敌百虫制作家兔急性有机磷中毒动物模型,在死后0～72h内不同时间点,采用留置微量重复取样法吸取眼玻璃体液,以全自动生化分析仪测量眼玻璃体液中钾、镁、磷、钙、钠、氯浓度的变化,统计数据进行二项式回归方程拟合分析。结果家兔急性有机磷中毒死后72h眼玻璃体液中钾、镁、磷随PMI延长而逐渐升高,舻分别为0．9818、0．9700、0．9458,与PMI相关性好,其中30h内镁的相关性更好;钙、钠随PMI延长呈降低趋势,砰分别为0．7124、0．7355,相关性较差;氯表现不稳定掣仅为0．0869。结论家兔急性有机磷中毒死后玻璃体液中钾、镁、磷、钙、钠等离子浓度随PMI延长而改变,72h内总体衡量,钾与PMI最具有相关关系。     

死后小鼠脑组织细胞核DNA变化规律的研究

目的研究DNA降解变化与死亡时间的关系,为法医学推断死亡时间提供一种比较准确可靠的新方法。方法应用单细胞凝胶电泳（SCGE）技术结合荧光显微镜和专业的计算机图像分析技术,测定了111只小鼠在死后72h内不同时间点小鼠脑组织细胞核头半径（HeadRadius,HR）、尾长度（Tail Length,TL）、头DNA（HeadDNA）含量比例、尾DNA（Tail DNA）含量比例、尾矩（Tail Moment,TM）、Olive矩（Olive Moment,OM）、头面积（Head Area,HA）、尾面积（Tail Area,TA）8项参数的变化值。结果在个体死亡72h内,测定的8项参数指标中尾DNA含量比例、彗星尾长、尾矩、Olive矩、尾面积都呈增加趋势,头半径,头DNA含量比例,头面积均呈下降趋势。上述参数均与死亡时间具有高度的相关性。并将每个参数的测量值进行了多项式运算,获得了更能体现DNA降解趋势的二项式回归方程（P〈0．001）和多元回归方程（P〈0．001）,均具有高度的统计学意义。结论应用本研究提供的72h内脑组织DNA变化与死亡时间之间呈线性关系的各组回归方程,为法医学推断死后经过时间提供了一种新的、客观的、精确的方法和参考依据。     

Estimation of postmortem interval from hypoxic inducible levels of vascular endothelial growth factor

Estimation of the postmortem interval (PMI) is one of the most important tasks in forensic medicine. Five autopsy organ tissues such as brain, lungs, heart, liver, and kidneys were taken at the time of forensic autopsy from 19 known PMI cases with a range of postmortem intervals ranging from 1 to 120 h (the mean was 25.81 h), and the time-course of vascular endothelial growth factor (VEGF) expression was measured. The human hepatoma-derived Hep 3B cell line was used as a control. The levels of VEGF increased linearly with the PMI up to 20 h in lung (r = 0.95 and in kidney (r = 0.89), and up to 15 h PMI in liver (r = 0.88). The VEGF levels fell after 24 h PMI, and then remained stable. In brain, the levels of VEGF started to increase after 24 h PMI and increased linearly with PMI up to 40 h in brain (r = 0.94) and then begin to fall. In heart, there was no clear correlation between the PMI and VEGF level. Some variations occurred in selected cases, such as the infant and asphyxial deaths. In conclusion, measurement of hypoxia-inducible levels of VEGF in various body organs appears to be a useful method of estimating the PMI up to 24 h in forensic medicine and pathophysiology. This method is also probably applicable in ischaemia in clinical and basic medicine.     

多温度下死后心血pH值随时间变化的三维拟合函数研究

目的 探讨通过测量多温度条件下家兔右心血液pH值进行死亡时间推断的可行性.方法 48只家兔随机分为6组,空气栓塞法处死后于10℃、15℃、20℃、25℃、30℃和35℃的不同死亡时间点采集右心血液;用PB-10型pH仪测量样本pH值;SPSS统计软件进行回归分析;MATLAB软件进行数学分析.结果 各温度组右心血液pH值变化与死亡时间呈高度相关(R2=0.974 ～0.982);获得拟合的曲面方程.结论 利用插值函数拟合pH值与死亡时间的曲面方程可进行温度变化条件下的死亡时间推断.     

Do bone elasticity and postmortem interval affect forensic fractographic analyses?

Forensic fractographic features of bone reliably establish crack propagation in perimortem injuries. We investigated if similar fracture surface features characterize postmortem fractures. Experimentally induced peri- and postmortem fractures were used to assess if fractographic features vary as bone elasticity decreases during the postmortem interval (PMI). Thirty-seven unembalmed, defleshed human femoral shafts from males and females aged 33–81 years were fractured at varying PMIs with a drop test frame using a three-point bending setup and recorded with a high-speed camera. Vital statistics, cause of death, PMI length, temperature, humidity, collagen percentage, water loss, fracture energy, and fractography scores were recorded for each sample. Results showed that fractographic features associated with perimortem fractures were expressed in PMIs up to 40,600 accumulated degree hours (ADH), or 60 warm weather days. Hackle was the most consistently expressed feature, occurring in all fractures regardless of ADH. The most variable characteristics were wake features (78.4%) and arrest ridges (70.3%). Collagen percentage did not correlate strongly with ADH (r = −0.04, p = 0.81); however, there was a strong significant correlation between ADH and water loss (r = 0.74, p < 0.001). Multinomial logistic regression showed no association between fractographic feature expression and ADH or collagen percentage. In conclusion, forensic fractographic features reliably determine initiation and directionality of crack propagation in experimentally induced PMIs up to 40,600 ADH, demonstrating the utility of this method into the recent postmortem interval. This expression of reliable fractographic features throughout the early PMI intimates these characteristics may not be useful standalone features for discerning peri- versus postmortem fractures.     

Estimation of postmortem interval using an electric impedance spectroscopy technique: A preliminary study

The objective of this study was to develop a rapid method for the estimation of postmortem interval (PMI) using electric impedance spectroscopy. Postmortem rat spleens were studied at 10 °C, 20 °C, and 30 °C; The results obtained demonstrated that postmortem interval negatively correlated with the absolute value of Im Z^// (capacitive reactance component) in electrical impedance. This suggests that electric impedance spectroscopy may be a sensitive tool to determine the postmortem interval.     

尸体心血红细胞ATP降解规律与早期死亡时间的相关性

目的观察早期死亡时间（PMI）与血液红细胞ATP含量的相关性。方法选择具有确切死亡时间的尸体30例,在死亡后6、8、10、12、14、16、18、20、22、24h分别于第4肋间进行心脏穿刺取血,利用生物发光法检测血液样本红细胞ATP含量（μmol／gHb）,并观察红细胞ATP含量变化与死亡时间的关系。结果尸体心血红细胞ATP含量在死亡后1～24h之内呈现非匀速下降趋势,与死亡时间的Pearson相关系数为-0．971（P=0．000）;尸体心血红细胞ATP含量与死亡时间的回归方程及尺。值为：Y=-0．096X＋2．872（x为死亡时间）,R2=0．936,P=0．000。结论尸体心血红细胞ATP含量在死后1—24h之内的变化与死亡时间具有相关关系,可以作为法医学死亡时间推断的生物学指标。     

Vitreous humor chemistry: the use of potassium concentration for the prediction of the postmortem interval

Upon review of the literature, extensive disagreement was found as to the usefulness of vitreous humor potassium concentration as a predictor of the postmortem interval (PMI). A pilot study of 1427 cases was performed to address this problem. The requisite statistical analysis for the prediction of PMI is inverse prediction. The 95% inverse prediction interval was found to be approximately +/- 20 h. The linear regression equation for the data was y = 0.238 chi + 6.342, with a coefficient of determination (r2) of 0.374. This r2 value means that 62.6% of the variation of potassium is unaccounted for by the variation in PMI. Further studies are required to attribute this unaccounted variation to quantifiable factors. This would narrow the inverse prediction interval and enable vitreous potassium to be a useful aid in the prediction of PMI.     

利用人体标本进行死亡时间推断的研究现状

死亡时间(PMI)推断具有重要的法医学意义,但尚无可以应用在实践领域的PMI推断方法。本文从PMI推断的实践应用角度出发,从脏器、骨骼、骨骼肌、牙齿、牙龈以及大体观、毛发、皮肤和血液等角度,对利用人体标本进行死亡时间推断的研究现状进行了综述。希望对我国开展人体标本的PMI推断实践研究提供借鉴。     

免疫印迹检测人胸大肌肌钙蛋白I推断较晚期死后经过时间

目的研究人死后骨骼肌肌钙蛋白I(Skeletal troponn in I,sTnI)的变化规律,探讨较晚期死后经过时间推断方法。方法以人胸大肌为研究对象,利用免疫印迹(W estern b lot)结合图象分析技术半定量检测不同离体时间内人胸大肌sTnI的含量,观察其与离体时间的关系。结果人胸大肌sTnI含量随离体时间延长而逐渐下降,与离体时间的对数值呈近似的线性关系:Y=11 972.5-4 761.9 lgX,相关系数r=0.989;离体5d的人胸大肌仍可检出sTnI。结论检验人死后骨骼肌(胸大肌)sTnI的含量有望成为用于推断人体较晚期死后经过时间的新技术。     

家兔死后心血氧化还原电位值变化与死亡时间的关系

目的研究在不同温度条件下家兔死后心血氧化还原电位(oxidation reduction potential,ORP)值变化与死亡时间(postmortem interval,PMI)的关系。方法随机将48只家兔分为6组,以空气栓塞法处死后,取家兔右心室血液分别置于10、15、20、25、30和35℃温度下的水浴中,自取血即刻(0h)至死后132h内,每4 h用PB-21型电化学分析仪测定样本的ORP值。应用SPSS 17.0软件建立曲线回归方程,再应用MATLAB7.10.0软件建立曲面方程和三维曲面图。结果不同温度条件下家兔心血ORP值变化与PMI具有高度相关性,温度高时,ORP值上升明显,温度低时,ORP值上升缓慢,并获得拟合的曲面方程以及三维曲面图。结论拟合的ORP值与PMI的曲面方程及三维曲面图可进行温度变化条件下的PMI推断。     

Using accumulated degree-days to estimate the postmortem interval from decomposed human remains

Forensic anthropologists often rely on the state of decomposition to estimate the postmortem interval (PMI) in a human remains case. The state of decomposition can provide much information about the PMI, especially when decomposition is treated as a semi-continuous variable and used in conjunction with accumulated-degree-days (ADD). This preliminary study demonstrates a supplemental method of determining the PMI based on scoring decomposition using a point-based system and taking into account temperatures in which the remains were exposed. This project was designed to examine the ways that forensic anthropologists could improve their PMI estimates based on decomposition by using a more quantitative approach. A total of 68 human remains cases with a known date of death were scored for decomposition and a regression equation was calculated to predict ADD from decomposition score. ADD accounts for approximately 80% of the variation in decomposition. This study indicates that decomposition is best modeled as dependent on accumulated temperature, not just time.     

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。     

Preliminary study of the effect of acute antemortem haemorrhage on postmortem abdominal impedance in rats

Studies over many years have revealed a consistent, inverse relationship between extracellular impedance of the rat abdomen and postmortem interval (PMI). Recent studies have shown that this relationship can be improved by correcting measured impedances to their theoretically predicted values at an arbitrarily chosen temperature of 40 degrees C, thus rendering them independent of the tissues' temperature at the time of impedance measurement. The present study, undertaken as a part of an ongoing effort to identify variables which might influence postmortem rate of change in abdominal impedance, was aimed at studying the possible effect of acute antemortem haemorrhage on abdominal impedance. Sudden loss of approximately 30% of the total blood volume, immediately prior to the death was without statistically significant effect on the pattern of postmortem change in abdominal impedance. Thus, in the control and experimental rats, respectively, impedance decreased progressively from 58.7 +/- 1.8 and 68.0 +/- 11.3 omega, 1 h postmortem, to 31.5 +/- 2.2 and 33.7 +/- 4.7 omega at a postmortem interval of 120 h (n = 6 in each group). In both groups, the relationship between impedance and postmortem interval was either linear or curvilinear. These findings are believed to mitigate in favour of continued effort to examine the potential usefulness of abdominal impedance, as an index of postmortem interval, under conditions encountered in routine forensic investigation.     

蛋白质降解与死亡时间推断的初步研究

目的观察大鼠肝脏肌动蛋白、微管蛋白在死后不同时间的降解情况,为死亡时间的推断寻找客观依据。方法大鼠麻醉致死后置于21℃温度控制系统模拟死后18d的改变,在不同时间点剪取肝脏组织抽提蛋白质,利用westernblot技术检测肌动蛋白、微管蛋白的降解变化并对产物进行半定量分析。结果大鼠肝脏肌动蛋白在死后8d尚可检测,死亡10d后检测不到;在死后2d,α微管蛋白已检测不到,但可检测到β微管蛋白,死亡4d后,β微管蛋白也检测不到。结论肌动蛋白、微管蛋白的死后降解存在差异,其在肝脏组织保存时间的不同可作为死亡时间推断的参数。     

Determination of postmortem interval from old skeletal remains by image analysis of luminol test results.

The luminol test is routinely used in forensic serology to locate blood traces and identify blood stains not visible to the naked eye; its sensitivity is reported as ranging from 1:100,000 to 1:5,000,000. To evaluate the possibility of correlating the postmortem interval with blood remnants in bone tissue, the luminol test was performed on 80 femurs with a known time of death, grouped in five classes. Powdered bone (30 mg) was recovered from compact tissue of the mid-shaft of each femur and was treated with 0.1 mL of Luminol solution (Sirchie Finger Print Laboratories, Inc.). The reactions were observed in a dark room and filmed by a TV camera equipped with a recording tape. An intense chemiluminescence was observed after a few seconds in all 20 femurs with a PMI ranging from 1 month to 3 years. On the 20 femurs with a PMI ranging from 10-15 years, a clear chemiluminescence was visible with the naked eye in 80% of the sample. Among the 20 femurs with a PMI ranging from 25 to 35 years, a weaker chemiluminescence appeared in 7 femurs (33% of the sample). In the 10 femurs with a PMI ranging from 50 to 60 years, a faint reaction was observed only in a single femur. In none of the ten femurs with a PMI over 80 years was chemiluminescence observed. The image of each reaction was computerized and analyzed for gray scale. The results of image analysis show a possible quantitative relationship between the PMI and luminol chemiluminescence in powdered bone.