肋软骨及牙髓细胞DNA含量与PMI的相关性

目的探讨人死后肋软骨及牙髓细胞平均DNA含量与死亡时间(PMI)的相关性,寻求推断PMI的新方法。方法应用细胞图像分析技术分析高温(30～35℃)及低温(15～20℃)环境下人死后0～15d两种组织细胞平均DNA含量的降解情况。结果两种组织细胞平均DNA含量随死后时间的延长而逐步降解,其中低温组牙髓细胞平均DNA含量的降解在死后0～4d内有一个降解平台期。统计分析两组温度下两种组织细胞平均DNA含量与PMI有显著的负相关性(P<0.01)。结论依据两种组织细胞平均DNA含量的降解可进行PMI推断。     

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。     

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.     

DNA含量变化与死亡时间推断的研究进展

在法医学实践中,死亡经历时间的推断具有重要的实践价值,但其准确推断却一直是法医学实践的难题,因而也一直是法医学研究的热点。法医DNA技术是近年来发展起来的在分子水平进行死亡时间推断的新技术、新方法,同传统方法相比,具有很大的优势,本文对该技术提出的背景、发展、优缺点以及发展前景进行综述,着重对DNA含量变化与其相关性的研究进展进行讨论。     

不同死亡方式大鼠心肌组织中ATP、ADP和AMP含量比较

目的比较不同死亡方式对大鼠心肌组织能量物质变化的影响,为判断不同死亡方式及死亡时间提供依据。方法180只大鼠随机分为三组,以不同方式(失血、窒息、断颈)处死,高效液相色谱法检测死后0、0.5、1、1.5、2、3、4、6、8、12、18和24h大鼠心肌组织中的ATP、ADP、AMP含量。结果三组不同死亡方式大鼠心肌组织的ATP、ADP、AMP的含量在大部分时间点做组间比较有明显差异(P<0.05);每组不同死亡方式的大鼠心肌组织中ATP、AMP的含量随时间的变化有明显的差异(P<0.01),而各组中的ADP在死亡一定时间后无明显差异。结论不同死亡方式的大鼠心肌组织中能量物质死后变化可以用作对死亡方式及某种方式不同死亡时间做出判断的依据。     

Further investigations into the speed of cerebral swelling following blunt cranial trauma

An anesthetized sheep model of traumatic brain injury (TBI) has been developed to assess early changes in intracranial pressure (ICP) following closed head injury. Immediately after TBI, a transient (<10 min) hypertensive response occurred, followed by significant and prolonged systemic hypotension. ICP demonstrated a biphasic response, being seven times baseline values of 8 ± 2 mm Hg 10 min after injury, decreasing to 25 ± 2 mm Hg by 30 min, and then increasing to values exceeding 30 mm Hg by 4 h postinjury. ICP was always significantly higher than baseline values, which combined with hypotension, reduced cerebral perfusion pressure to less than 60% of normal. This early and sustained increase in ICP after craniocerebral trauma acutely alters cerebral perfusion pressure and brain oxygenation and provides a potential pathophysiological explanation for immediate clinical manifestations in humans following significant TBI.     

Exsanguinated blood volume estimation using fractal analysis of digital images

The estimation of bloodstain volume using fractal analysis of digital images of passive blood stains is presented. Binary digital photos of bloodstains of known volumes (ranging from 1 to 7 mL), dispersed in a defined area, were subjected to image analysis using FracLac V. 2.0 for ImageJ. The box-counting method was used to generate a fractal dimension for each trial. A positive correlation between the generated fractal number and the volume of blood was found (R(2) = 0.99). Regression equations were produced to estimate the volume of blood in blind trials. An error rate ranging from 78% for 1 mL to 7% for 6 mL demonstrated that as the volume increases so does the accuracy of the volume estimation. This method used in the preliminary study proved that bloodstain patterns may be deconstructed into mathematical parameters, thus removing the subjective element inherent in other methods of volume estimation.     

A test for carrion fly full siblings: a tool for detecting postmortem relocation of a corpse

We propose a genetic test for full sibship for a pair of carrion flies that could reveal the postmortem relocation of a corpse. A carrion fly larva is sometimes left behind when a corpse is moved. The discovery of full sibling larvae of approximately the same developmental stage at two locations would strongly suggest that a corpse was moved between those two sites. Distributions of pairwise comparisons of relatedness (R) coefficients were generated using amplified fragment length polymorphism profiles for nine samples of laboratory-generated full siblings as well as for a reference sample of nonfull sibling Phormia regina (Diptera: Calliphoridae). The mean relative R coefficient, a pairwise measure of the proportion of shared alleles, was 0.479 (±0.289 SD) for full siblings, close to the theoretical expectation of 0.5. A likelihood ratio (LR) test was based on observed distributions of R. R >0.55 corresponded to an LR >1000 favoring full sibship for that pair of individuals.     

Humeral and femoral head diameters in recent white American skeletons

Osteologists often rely on single measurements, such as humeral and femoral head diameters, to estimate sex, especially when skeletons are incomplete. Measurements of 237 Bass Donated Collection skeletons provide a means of distinguishing white American females from males based on a modern sample: humeral head, female mean 42.1 mm, male mean 49.0 mm; and femoral head, female mean 42.2 mm, male mean 48.4 mm. Probabilities that bones at 1-mm increments came from females (p(f)) are estimated (p(m) = 1 - p(f)). An overrepresentation of one sex in the skeletons that are examined influences the probability that a bone of a certain size is from a female or male. So, probabilities are also estimated for samples consisting of an unequal number of males and females. Sample composition has its greatest effect when one sex dominates the remains that are the subject of investigation.     

胸骨形态变化与年龄关系的研究进展

胸骨在发育和退化的过程中,随年龄增长发生着规律性形态改变.国内外学者对胸骨形态变化与年龄的关系做了大量研究,积累了一些宝贵资料,这些成果为研究胸骨三维重建影像的形态变化奠定了基础.三维重组技术的引入,有望引起利用胸骨推断活体年龄方法的突破性发展.本文对相关研究进展进行综述.