Postmortem interval estimation by creatinine levels in human psoas muscle.

A new method was tested for estimating time after death in the middle range of postmortem interval (weeks). Creatinine muscular concentration in human cadaver is positively correlated to postmortem estimation. Temperature should be mainly related to the creatinine transformation rate. A stronger correlation was found at 11 degrees C up to 30 days and at 20 degrees Celsius up to 15 days.     

Urea,Uric Acid,and Creatinine in Postmortem Blood,Vitreous Humor,and Synovial Fluid: A Comparative and Correlation Study,

Urea, uric acid, and creatinine have been demonstrated to be relatively stable in postmortem blood (BL), thus being useful for diagnostic purposes. However, no studies have explored their levels in BL, vitreous humor (VH), and synovial fluid (SF) concurrently. Therefore, we measured and compared their levels in these fluids. We also determined the effects of various factors on their levels. The results indicated that BL urea, uric acid, and creatinine levels were significantly higher than VH and SF levels. VH and SF urea levels and SF creatinine levels had a strong correlation with BL urea and creatinine levels, respectively. BL creatinine levels were higher in men than in women. BL and SF creatinine levels were negatively correlated with age. SF uric acid and BL, VH, and SF creatinine levels exhibited a positive correlation with weight. Only VH creatinine levels were positively correlated with body mass index. None of urea, uric acid, and creatinine levels were correlated with postmortem interval.     

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。     

应用DNA3’末端转移推测死亡时间

目的根据机体死后组织细胞DNA降解规律,研究其与死亡时间之间的关系.方法SD大鼠处死后,在不同死亡时间段取肝、肾、脾组织提取DNA.根据DNA3′末端转移的方法(TdT法)将dUTP结合到DNA的3′末端,检测反应剩余的dUTP量,从而推测机体死后不同时间段DNA的降解情况.结果经对剩余dUTP检测发现,dUTP的剩余量随死亡时间延长而减少,说明DNA降解与死亡时间存在一定的关系.结论根据机体死后DNA降解规律可用于早期死亡时间的推测.     

Aqueous Fluid as a Viable Substitute for Vitreous Fluid in Postmortem Chemistry Analysis

Vitreous fluid sampling for postmortem chemistry analysis is discouraged in pediatric forensic cases involving head trauma due to the risk of introducing retinal artifacts. Aqueous fluid is physically separated from the posterior chamber of the eye, and therefore, unlikely to produce vitreal artifact when sampled. Analysis of aqueous fluid is therefore proposed as a substitute for vitreous. Vitreous and aqueous fluid was sampled concurrently from 28 pediatric and 55 adult decedents, and sodium (Na), potassium (K), chloride (Cl), urea nitrogen (UN), creatinine (Cr), and glucose (Glc) concentrations were compared. Significant correlation existed between all analytes regardless of age or postmortem interval, and linear regression equations were derived. Aqueous concentrations were generally higher than vitreous for Na, K, and Cr and were marginally lower for Cl, UN, and Glc. Assuming vitreous fluid as a standard for correlating postmortem chemistry to antemortem serum values, aqueous may be a viable substitute for vitreous when expected differences are considered.     

The estimation of the time of death by non-protein nitrogen (NPN) in cadaveric materials. Report 3: Multiple regression analysis of NPN values in human cadaveric materials

The non-protein nitrogen (NPN) values in brain, lung, liver, and kidney in 79 autopsy cases were determined according to the Micro-Kjeldahl Nessler method. Multiple regression analysis of the data was performed with every possible combination of the time of death and the NPN values in the tissues.The brain NPN showed the best correlation with the postmortem time (r = 0.673), whereas the other correlations were less satisfactory (lung r = 0.422, liver r = 0.397, and kidney r = 0.379, respectively). However, multiple combinations of each tissue NPN value proved to give better correlation coefficients and smaller errors of the estimated time of death.The practical significance of the tissue NPN as a postmortem biochemical indicator of the time of death and the multiple regression analysis of such indicators were extensively discussed in this report.     

Vitreous humor biochemical constituents: evaluation of between-eye differences

The present study was conducted to investigate the differences in the vitreous humor biochemical concentrations for vitreous electrolytes and calcium in the same pair of eyes at identical postmortem interval (PMI). The vitreous humor samples were collected independently in both eyes from 48 autopsies (PMI range, 4.5-84.3 hours) with documented time of death. The samples were analyzed for potassium, sodium, chloride, and calcium using a Beckman Coulter LX20 Automated Analyzer based on ion-selective electrode methodology. There were no statistically significant between-eye differences at identical postmortem interval. A significantly high correlation was observed between paired potassium concentrations of both the eyes. A highly significant linear correlation was observed between the individual eye and mean potassium concentrations of both the eyes with postmortem interval. The observed differences were not significantly correlated with postmortem interval. The results demonstrated that the between-eye differences for vitreous electrolytes and calcium are insignificant. Therefore, the utility of vitreous biochemistry, particularly potassium in postmortem interval estimation and other forensic applications, cannot be questioned solely on the basis of these differences.     

单细胞凝胶电泳分析死后小鼠骨骼肌细胞核DNA降解

目的研究小鼠死后骨骼肌细胞核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,测定111只小鼠在死后72h内不同时间点骨骼肌细胞核DNA电泳形状的8项参数值,所得数据进行统计学分析。结果在个体死亡72h内,“彗星”的尾DNA含量比例、尾长、尾矩、O live矩、尾面积数值随时间的延长而增大;而“彗星”的头半径,头DNA含量比例和头面积数值则随时间的延长而减小。经对每个参数的测量值进行多项式运算,获得DNA降解趋势的二项式回归方程(P<0.001)和多元回归方程(P<0.0001),且均具有极显著性意义。结论在死后一定时间内,小鼠骨骼肌组织核DNA降解随死后经过时间的变化而呈一定规律性变化,DNA降解与死亡时间之间呈线性相关。     

Determination of calcium and magnesium in postmortem human vitreous humor as a test to ascertain the cause and time of death

The concentrations of magnesium and total calcium human vitreous humors obtained postmortem was tested. In the groups of heart disease and asphyxia a correlation between the postmortem interval and calcium or magnesium concentrations was found. There was no correlation between postmortem interval and calcium respectively magnesium in the other causes of death. It seems possible that the analysis of vitreous humor may be useful in both diagnosis and determination of postmortem interval in the cases of heart death and asphyxia.     

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。     

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。     

小鼠心肌细胞核DNA变化与死亡时间的关系

目的监测小鼠死后细胞核DNA降解的情况,探讨死后细胞核DNA降解的一般规律。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111只小鼠在死后72h内不同时间点小鼠心肌组织细胞头半径、尾长度、头DNA含量比例、尾DNA含量比例、尾矩、Olive矩、头面积、尾面积八项参数的变化值。结果在个体死亡72h内,测定的八项参数指标均显示细胞核DNA降解速率和程度与死亡时间具有高度的相关性,并获得了更能体现DNA降解趋势的二项式回归方程和多元回归方程,均具有高度的统计学意义。结论应用72h内心肌组织DNA变化与死亡时间之间呈线性关系的各组回归方程,可为法医学推断死后经过时间提供一种新的、客观的、精确的方法和参考依据。     

Estimation of postmortem interval using kinetic analysis of the third component of complement (C3) cleavage

To estimate postmortem interval (PMI), spontaneous cleavage of the third component of complement (C3) was studied in aged blood and cadaveric blood by crossed immunoelectrophoresis. Using the kinetics of C3 cleavage in vitro described as dC/dt = -kC, where C is the concentration of native C3 at time t and k is a first-order rate constant, Arrhenius' equation, and another equation which assumes a linear drop of body temperature after death, the percentages of C3 cleavage were calculated. There was a significant positive correlation between the calculated percentages and the measured percentages of up to 10% in cadaveric blood. We found that the comparison between the calculated percentage of C3 cleavage for each optional postmortem interval and the measured percentage of up to 10% in cadaveric blood leads to the estimation of PMI. This approach is one step towards the development of an accurate method for determining PMI based on C3 cleavage, that is, on a first-order reaction.     

尸温相关因素推断死亡时间的研究

目的 统计分析影响尸体温度下降多因素和死亡时间的相关性,探索尸温推断死亡时间的创新应用.方法 建立影响尸体温度(直肠温度)下降相关因素的采集标准,收集实践工作中的157例明确死亡时间真实案例的相关数据,根据实际工作经验结合统计学的基本要求对各因素进行量化评分,利用EXCEL和SPSS软件对数据进行处理,采用多元线性回归的方法统计分析各影响系数同死亡时间的相关性.结果 获得了具有统计学意义的回归方程,Y=25.993+0.04X1+0.172X2+0.88X3+0.047X4+0.373X5+0.347X6-0.766X7,决定系数R2=0.876.结论 该方法为尸温推断死亡时间的创新应用,经测试可用于实际工作.     

The use of absolute refractory period in the estimation of early postmortem interval

The estimation of the time since death (postmortem interval) is one of the most difficult problems in forensic pathology. Most methods currently employed use temperature-based algorithms intended to model the cooling of the body after death and thus estimate the postmortem interval. These methods are subject to considerable inaccuracy but their reliability can be improved if a range of other observed criteria such as lividity and rigor are also taken into consideration. The aim of the present study was to investigate the feasibility of using the absolute refractory period as an adjunct to the estimation of postmortem interval. The relationship between the `postmortem interval' and the `duration of absolute refractory period' was investigated using the rat sciatic nerve. A strong correlation between the duration of the absolute refractory period and the postmortem interval was observed. When both absolute refractory period and temperature were used in conjunction, the strength of this correlation was increased.     

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.     

Amount of postmortem bleeding: an experimental autopsy study

An experimental autopsy study was performed on 64 cases (55 male, 9 female; average age 51.5 +/- 16.2 years) of sudden natural (38 cases) and asphyxic deaths (26 cases). The study objective was the amount of postmortem bleeding from postmortem cutting of the thoracic aorta, related to the time since death. The amount of postmortem bleeding ranged from 100 to 1300 cm, 440.6 +/- 268.1 cm on average. The time since death up to the autopsy time ranged from 4 to 72 hours, 19.4 +/- 12.9 in average. A statistically significant correlation between the amount of postmortem bleeding and postmortem time interval was stated: Pearson correlation test value r = -0.461 (P = 0.000): the shorter the time interval, the larger the amount of bleeding. The formula of linear regression was estimated according to this correlation: amount of postmortem bleeding (cm) = -9.571 x time since death (h) + 626.659. This proves that the amount of postmortem bleeding (eg, from aortic blunt rupture) could be about 620 cm.     

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.     

大鼠死后心肌骨骼肌细胞肌动蛋白变化及与死亡时间的关系

目的　探讨大鼠死后心肌骨骼肌细胞肌动蛋白的变化及其与死亡时间的关系。方法　采用免疫组化S P法和IBSA图像分析系统 ,观测大鼠死后不同时间心肌骨骼肌抗肌动蛋白单克隆抗体 (HHF3 5 )染色变化。结果　在大鼠死后 5 4h内 ,心肌骨骼肌呈不同程度的HHF3 5缺染 ,其面积随死后时间的延长而增大。经对IBSA图像分析数据进行方差分析 (F心肌 =5 88 2 7,F骨骼肌 =3 5 1 2 5 ,P <0 0 5 ) ,具有显著性差异 ;经逐步回归分析 (r心肌 =0 943 ,r骨骼肌 =0 95 8,P <0 0 5 ) ,具有正相关关系。所建方程y心肌 =-3 0 5 68+1 0 0 3x1,y骨骼肌 =-2 4 897+0 986x2 (X为HHF3 5缺染面积均数 )具有统计学意义。结论　在一定时间内 ,大鼠死后不同时间心肌骨骼肌细胞HHF3 5缺染面积 ,随死后时间的延长而增大。     

Vitreous humor magnesium in alcoholics

Postmortem vitreous humor magnesium concentrations were determined in 27 alcoholics and in 27 nonalcoholics who died of various causes. No significant differences in magnesium values were present between these two groups. The concentrations in those dying with alcohol withdrawal syndrome or in those with postmortem findings limited to hepatic fatty change did not differ significantly from those in the nonalcoholic group or from those of the alcoholics dying of other causes. There was no correlation between vitreous humor magnesium concentrations and postmortem interval in any group. We conclude that vitreous humor magnesium determination is not helpful in the postmortem evaluation of suspected alcohol-related deaths or in determining postmortem interval.