玻璃体液化学成分规律性改变与死亡时间推断的研究进展

死亡时间（postmortem interval．PMI）的准确推断是法医尸体检验工作中的难题之一,PMI推断对刑事案件的侦察和审判具有重要的意义。人死亡后不同时间眼玻璃体液化学成分的规律性变化,如钾、镁、氨、尿素氮、肌酐和尿酸、次黄嘌呤、乳酸的含量逐渐升高,而钙、钠、酶类、葡萄糖、维生素C的含量逐渐降低,有助于比较准确地进行PMI推断。本文对其在法医学领域的研究进展进行综述。     

家兔眼玻璃体液21例元素含量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),系统研究了家兔死后96h内眼玻璃体液21种元素含量与PMI的相关性。结果眼玻璃体液Co、Mo、Cd、Sb、I、Pb、Bi、Li共8种元素与PMI无关。K、Mg、Fe、P、Na、Al、Ca、Ti、Ni、Cu、Zn、Sr、Ba共13种元素含量与PMI有关。结论眼玻璃体液K、Mg、Fe、P、Na、Al、Ca、Ti、Ni、Cu、Zn、Sr、Ba共13种元素与PMI有关。为研究人尸体眼玻璃体液元素与PMI的关系奠定了选择指标的基础。     

Comparison of chemical methods for determining postmortem interval

Accurate determination of postmortem interval (PMI) is a problem for the forensic thanatologist, especially in unwitnessed deaths. A number of objective chemical methods for determining PMI have been developed, the most widely used being accumulation of potassium in the vitreous humor. The authors previously have reported a chemical method for determining PMI from the predictable accumulation or clearance of the dopaminergic metabolite 3-methoxytyramine (3-MT) in the putamen of the brain. They have extended their previous study to compare directly the accuracy of determining PMI from the level of 3-MT in putamen with the level of potassium in vitreous humor. The data indicate that 3-MT is at least as accurate as, if not more accurate than, potassium accumulation in vitreous humor, although 3-MT levels can be affected by the cause of death and drugs present at the time of death. Nevertheless, determination of both the 3-MT and potassium levels can afford the most accurate method of determining PMI; preliminary nomograms for determining PMI from both variables are presented.     

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.     

死后眼组织变化与死亡时间推断

眼组织推断死亡时间一直是国内外法医学界的研究热点之一,从肉眼观到镜下观,从细胞水平到分子水平,不断有新的研究成果和报告出现。大量研究资料表明,随着死亡时间的延长,眼角膜、视网膜、玻璃体液及房水等均出现规律性的变化,并与死亡时间高度相关,可用于死亡时间推断。本文对其在法医学领域的研究进展作以综述。     

家兔死后玻璃体液电导率变化与死亡时间的关系

目的探讨家兔死后玻璃体液电导率变化与死亡时间的相关性。方法采用电导分析法检测家兔30℃下死后48h内及20℃下死后120h内玻璃体液电导率变化。结果30℃和20℃下家兔死后玻璃体液电导率随死亡时间延长而持续升高。经统计分析得到抛物线型二项式回归方程,其相关系数分别为0.970和0.983,两式P〈0.01。结论家兔死后玻璃体液电导率升高程度可以作为推断死亡时间的参考指标。     

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。     

猪眼玻璃体液钾离子、次黄嘌呤浓度变化与PMI推断

目的 研究猪眼玻璃体液成分变化及其与死亡时间(postmortem interval,PMI)的关系.方法放血处死家猪后取带眼睑的眼球96只,随机分为24组,在避光、温度(15±2)℃、湿度(50±5)%条件下分别放置2～96h,采集玻璃体液,运用全自动生化检测仪、超高效液相色谱检测K+、Na+、Cl-及次黄嘌呤(hy...     

家兔死后眼玻璃体液消光度与死亡时间关系研究

目的 为寻找一种精确推定死亡时间的方法。方法 应用 754分光光度计,在 420nm波长下,检测了 48只家兔死后不同时间的眼玻璃体液消光度,探讨其与死亡时间的关系。结果 眼玻璃体液消光度（ X）与死亡时间（ Y）呈线性正相关（ r=0.983 27, P< 0.05）,在死后 0～ 72小时,眼玻璃体液消光度与死亡时间存在回归关系（ F=116.54, P< 0.05）,直线回归方程为： Y = 453.30X＋ 0.75 [Y为死亡时间 (PMI),单位为小时; X为眼玻璃体液消光度 ]。结论眼玻璃体液消光度的测定可作为推断死后 72小时内死亡时间的参考指标之一。     

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。     

双眼交替微量取样检测兔玻璃体液钾镁离子浓度推测死亡时间

目的研究死后眼玻璃体液钾镁离子浓度变化及其与死亡时间的关系。方法取健康家兔处死,死后不同时间于双眼玻璃体液交替微量取样,采用全自动生化分析仪检测样本中[K+]、[Mg2+],对所得数据进行统计学处理。结果死后12~120h,家兔玻璃体液中[K+]由11.01mmol/L上升至32.97mmol/L,[Mg2+]1.12mmol/L上升至2.22mmol/L,两种离子浓度与PMI进行回归分析自变量为[K+]的二次多项式回归方程为y=0.1756x2-3.3188x+29.804(R2=0.9868);自变量为[Mg2+]的二次多项式回归方程为y=-46.916x2+248.01x-213.81(R2=0.9340);自变量为[K+]和[Mg2+]的二次多项式回归方程为y=-17.55-4.82[K+]+0.20[K+]2+75.77[Mg2+]-19.47[Mg2+](R2=0.9881)。用[K+]的方程推测PMI,当[K+]<26.0mmol/L(PMI<60h)时,平均偏离时间为2.7~9.4h,当[K+]>28mmol/L(PMI>72h)时,平均偏离时间>15h;用[Mg2+]的方程推测PMI,平均偏离时间几乎均在10h以上;用二元方程推测PMI,平均偏离时间较前两者小。结论死后眼玻璃体液[K+]、[Mg2+]随时间延长而升高,且浓度变化与时间呈强相关性。但从实际运用角度考虑,R2<0.98,或平均预测偏离时间过大的回归方程,不宜用于PMI推测;应用多指标建立多元回归方程是提高推测PMI准确性的可行方法。     

A new perspective in the estimation of postmortem interval (PMI) based on vitreous

The relation between the potassium concentration in the vitreous humor, [K+], and the postmortem interval has been studied by several authors. Many formulae are available and they are based on a correlation test and linear regression using the PMI as the independent variable and [K+] as the dependent variable. The estimation of the confidence interval is based on this formulation. However, in forensic work, it is necessary to use [K+] as the independent variable to estimate the PMI. Although all authors have obtained the PMI by direct use of these formulae, it is, nevertheless, an inexact approach, which leads to false estimations. What is required is to change the variables, obtaining a new equation in which [K+] is considered as the independent variable and the PMI as the dependent. The regression line obtained from our data is [K+] = 5.35 + 0.22 PMI, by changing the variables we get PMI = 2.58[K+] - 9.30. When only nonhospital deaths are considered, the results are considerably improved. In this case, we get [K+] = 5.60 + 0.17 PMI and, consequently, PMI = 3.92[K+] - 19.04.     

The Application of Flow Cytometry as a Rapid and Sensitive Screening Method to Detect Contamination of Vitreous Humor Samples and Avoid Miscalculation of the Postmortem Interval

Research into maximizing the speed, precision, and reliability of estimating the postmortem interval (PMI) has been a recurring object of investigation and methodologies based on the vitreous humor (VH) have provided good results. However, contamination from causes not readily apparent, such as blood, can occur, and thus lead not only to an erroneous estimation of PMI, but also interfere with the correct identification of other substances in the VH. We have developed a flow cytometry method which quantifies blood contamination and is able to detect erythrocytes in 1:750,000 dilution of contaminated VH which affects the results of hypoxanthine. It is an improvement on the previous more complex mass spectrometry method, being faster, more sensitive, and readily available. As such, it could be proposed for the rapid screening of appropriate samples by detecting and eliminating blood contaminated samples from PMI estimation.     

家兔急性胰腺炎死后不同时间眼玻璃体液淀粉酶变化

目的探讨急性胰腺炎死后不同时间眼玻璃体液淀粉酶变化。方法用1%牛胆酸钠诱导家兔急性胰腺炎动物模型建立,于死后不同时间和正常对照组,观察其淀粉酶变化。结果家兔急性胰腺炎死后72h眼玻璃体液淀粉酶含量(x)与死亡时间(y)存在相关关系,并导出其二项式回归方程为y=8.7420 0.7699x-0.0083x2(R2=92.62792,F=14.89734,P=0.001)。可作为推定早期损伤时间的参考指标。结论家兔急性胰腺炎死后不同时间眼玻璃体液淀粉酶改变为法医早期死亡时间推断提供了灵敏客观的实验依据。     

家兔玻璃体液2种酶活性变化与死亡时间的相关性

目的探讨死后家兔玻璃体液胆碱脂酶(CHE)和谷草转氨酶(GOT)活性与死后经过时间(PM I)的相关性。方法应用光度法检测在25~30℃和10~15℃下死后即刻至54h之间玻璃体液CHE和GOT活性。结果死后即刻至54h之间,ChE、GOT活性分别由约850U/L、220U/L逐步降解趋于零。死后6h内,两种酶活性降解存在平台期。统计分析,得出相应的单元和多元回归方程,相关系数或决定系数均在0.896以上,P<0.01。结论两种酶活性的降解规律可作为较为客观的推断PM I的参考指标。     

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。     

A Study on the Estimation of Postmortem Interval Based on Environmental Temperature and Concentrations of Substance in Vitreous Humor

A method to determine postmortem interval (PMI) based on environmental temperature and the concentrations of vitreous humor (VH) molecules were explored. Rabbit carcasses were placed in a chamber at 5, 15, 25, or 35°C, and 80–100 μL of VH was collected with the double‐eye alternating micro‐sampling method every 12 h. A Roche DPPI biochemical analyzer was used to measure the concentrations of six substances in VH samples. The interpolation function model and mixed‐effect model were employed for data fitting to establish equations for PMI estimation. The concentrations of K⁺, P, Mg²⁺, creatinine (CRE), and urea nitrogen (UN) exhibited an upward trend with increasing PMI in all temperature groups, while the concentration of Ca²⁺ showed a downward trend. Validation results using K⁺ and Mg²⁺ ions revealed that the mixed‐effect model provided a better estimation than the interpolation function model using the data from our experiment. However, both models were able to estimate PMI using temperature and VH molecule concentrations.     

3-Methoxytyramine in the putamen as a gauge of the postmortem interval

The armamentarium of the forensic thanatologist includes the examiner's subjective assessment of bodily changes together with comprehensive evaluation of environmental and associated factors to estimate the postmortem interval (PMI). Of the various objective means, postmortem accumulation of potassium in vitreous humor is a widely used gauge. In view of the considerable variability inherent in these techniques, an additional marker with greater accuracy would be a welcome supplement to these indices. We have developed a method of estimating PMI from the level of 3-methoxytyramine (3-MT) in the dorsal putamen of the brain. The supernatant of a sample of putamen, sonicated in 6 volumes (weight/volume) of 0.1 M perchloric acid and centrifuged at 51 000 times gravity for 10 min, was analyzed for 3-MT using high-pressure liquid chromatography with electrochemical detection. The change of 3-MT in the putamen is linearly related to the PMI (range: 5.5 to 60 h), irrespective of patient age (1 to 84 years). This observation is attributable to several factors, including high substrate (dopamine) concentration, preservation of catechol-O-methyl transferase activity, and an inactivation of monoamine oxidase activity, as a result of a decrease in tissue pO2.     

核酸及蛋白质在死亡时间推断中的应用

死亡时间(postmortem interval,PMI)推断一直是法医学研究的重点与难点.机体死亡后,组织细胞发生自溶,核酸等大分子物质发生降解,其中DNA含量呈逐渐下降趋势,与PMI具有一定的线性关系,管家基因β-actin、GAPDH mRNA具有一定的稳定性,也可作为内参照进行PMI推测.本文综述了目前DNA、...     

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。