In vitro loss of potassium from erythrocytes during the 0-108 h postmortem period in rats: relationship between potassium loss and postmortem interval.

A simple technique was employed for measurement of potassium loss (K(los)s) from normal and from postmortem rat erythrocytes during controlled exposure to physiologically isosmotic NaCl solution. Potassium loss from the cells decreased in a (non-linear) time-related manner during the 0-108 h postmortem period; expression of the data in the form of a double logarithmic plot (log K(loss) versus log postmortem interval (PMI) linearized the relationship between 18 and 108 h post mortem (r = -0.86; P less than 0.001 (n = 24)). Experimental data revealed that the observed postmortem changes in K(loss) were associated with and probably resulted from, the postmortem decrease in magnitude of the potassium concentration gradient across the erythrocyte membrane. Attention is drawn to the possibility of utilizing measurements of in vitro loss of potassium from erythrocytes as a means of estimating time elapsed since death.     

Reconstruction of root morphology in skeletonized remains with postmortem dental loss.

A reversible technique is presented in which the root morphology of missing teeth in skeletonized human remains can be reconstructed for the purpose of radiographic comparison and postmortem identification. In this technique, which is based upon pilot studies with skeletonized mandibles of archival remains, the alveolar socket walls are sealed with a coat of cyanoacrylate cement and injected with a mixture of vinyl polysiloxane and barium sulfate. Radiographs are produced with the radiopaque mixture in place, which highlights the antemortem morphology of the roots. Subsequently, the impression material is removed, resulting in no gross alteration of the evidence. The radiographs made with this technique, as well as the impressions, can be stored for later use at a trial or pending the discovery of antemortem dental evidence.     

Factors affecting strontium absorption in drownings

This study examines the effects of age, gender, a cold water medium versus warm water medium, and salinity on strontium levels determined in left ventricular blood in drownings. Significant differences in the amount of strontium absorbed into the bloodstream (p<0.001) were detected between individuals who drowned in fresh water versus those drowning in seawater, and between those drowning in cold water versus warm water (p=0.030). However, no significant differences were noted in the strontium concentrations of left ventricular blood according to gender or age.     

Factors affecting perceptions of medical errors

The purpose of the study was to assess how three factors affect subjects' perceptions of a medical error made in a hypothetical scenario. The factors were (i) type of compensation system, (ii) degree of procedural “voice” present in the physician-patient relationship, and (iii) magnitude of damage sustained by the patient. Perceptions were defined to include subjects' (i) emotional reactions to the incident, (ii) causal attributions about the incident, (iii) evaluations of the faimess of the compensation systems, and (iv) compensation demands. Results indicated that damage magnitude was the only factor that affected subjects' emotional reactions to the described incident and their compensation requests. When damage was severe, subjects reacted more negatively to the event and demanded greater compensation. Subjects rated the no-fault system and greater voice conditions as more fair. In general, subjects causally analyzed the error incident in a manner that was less blameworthy of the physician when procedural justice was high, especially if this was combined with a no-fault compensation system. Results were discussed in terms of Wexler and Winick's (1991) model of therapeutic jurisprudence.     

Factors affecting decomposition and Diptera colonization.

Understanding the process of corpse decomposition is basic to establishing the postmortem interval (PMI) in any death investigation even using insect evidence. The sequence of postmortem changes in soft tissues usually gives an idea of how long an individual has been dead. However, modification of the decomposition process can considerably alter the estimate of the time of death. A body after death is sometimes subject to depredation by various types of animals among which insects can have a predominant role in the breakdown of the corpse thus, accelerating the decomposition rate. The interference of the insect community in the decomposition process has been investigated by several experimental studies using animal models and very few contributions directly on cadavers. Several of the most frequent factors affecting PMI estimates such as temperature, burial depth and access of the body to insects are fully reviewed. On account of their activity and world wide distribution, Diptera are the insects of greatest forensic interest. The knowledge of factors inhibiting or favouring colonization and Diptera development is a necessary pre-requisite for estimating the PMI using entomological data.     

人体内乙醇含量检测的影响因素分析

人体内乙醇含量检测不仅是法医鉴定工作中常规检测项目,也是交通肇事案件最终的仲裁依据,其检测结果直接影响着受检人员的责任判罚。本文根据乙醇的毒理特征及在人体内的代谢过程,就不同检材、送检时效性、尸体腐败、血液检品中不同成分和保存方式、以及检测结果的不确定度等对乙醇含量检测结果的影响进行分析,以利于对受检者是否饮酒及其程度做出科学、公正的判定。     

Factors affecting simulated jurors' decisions in capital cases

Abstract

Previous psycho-legal research has claimed that the process of selecting death-qualified jurors for capital cases creates conviction-prone juries. The studies on which these claims are based have employed simulation methodologies to examine the relationship between subjects' death-penalty attitudes and verdict decisions, as well as the effect of the death-qualifying voir dire itself. Despite admitted weaknesses of simulations in general, this method was employed in the present research so that conceptual comparisons to past findings could be drawn. Two experiments were designed to examine the issue of death-qualification and biased juries in a context of other potentially highly influential factors, namely, the strength of evidence and the degree of heinousness. Our results failed to find any of the relationships between death-penalty attitudes and verdict decisions that would be predicted from past research. Instead, the subjects' decisions were influenced, virtually exclusively, by the strength of the evidence presented in the case, as is legally prescribed. In the light of these findings, the discussion focused on the questions of reliability and external validity of simulation research, the potential problems caused by method-specific factors in determining the outcome of such methodology, the attitude-behavior link, and the danger of premature and un-warranted application to the legal system of findings from simulations.     

影响鉴定结论可靠性的相关因素研究

鉴定结论的可靠性是鉴定的基本价值所在,是鉴定的初始目标,是鉴定结论得以存在的基础。影响鉴定结论可靠性的因素既包括法律制度层面又包括技术层面,既有人的因素,也有物的因素。鉴定主体、实施程序及其鉴定结论标准等都是影响鉴定结论可靠性的重要因素,任何一个方面的差错都有可能导致鉴定结论缺乏可靠性。     

Factors affecting the forensic examination of automotive lubricating oils

Lubricating oil comparisons impact a variety of forensic investigations, including cases where oil was transferred from a suspect vehicle to the crime scene or victim. In this study, high-temperature gas chromatography/mass spectrometry was used to examine the influence of oil mixtures and oil changes over time on the comparison of known and questioned lubricating oils. Varying concentrations of oil mixtures were prepared and showed the potential for identifying individual components. Motor oils from 18 automobiles monitored over a 2-month period did not demonstrate significant changes in the chromatographic data. Chemometric analysis of motor oil mass spectral data provided little information regarding differentiation of, or changes in, the samples. Power steering fluid (PSF) from a naturally occurring leak collected from several locations was consistent with the PSF in the automobile's reservoir, and the PSF composition did not change over time.     

Factors affecting testimony about mitigating circumstances and the fixing of punishment

Although trial attorneys typically choose to have defendants testify on their own behalf, there are data from studies using simulated juries which suggest that the presentation of favorable testimony by defendants might be harmful. Data from these studies are suspect, however, because subjects' verdicts had no realworld consequences. In the present study the real-world consequentiality of subjects' verdicts (some vs. none), the presence of mitigating testimony (some vs. none), the source of the mitigating testimony (defendant vs. third party), and the credibility of mitigating testimony (high vs. low) were all manipulated in order to test their effects on the severity of penalities subjects assigned. The results showed that among subjects whose decisions were of no consequence, none of the other manipulated variables produced any reliable differences. On the other hand, among those who thought their decisions were of real consequence, less severe penalties were given when mitigating testimony was presented as opposed to when it was not, and more interestingly, this was true regardless of the testimony's source. The results are seen as underlining the importance of inducing a sense of consequence in simulated jury studies.     

血中碳氧血红蛋白饱和度测定影响因素的研究

目的 考察血中碳氧血红蛋白饱和度(HbCO％)测定的影响因素,为其结果评定和所需样品保存条件提供实验依据。方法 利用三种分光光度法,测定30d内不同条件下保存的CO阳性血的HbCO％的变化。结果 还原双波长法、双波长法测定结果比较稳定,单波长法抗干扰能力较差;尸检所取血样的保存条件包括温度、保存时间及与空气接触程度对HbCO％的测定均有影响,其中温度影响较为显著。结论 利用还原双波长法与双波长法,并结合光谱扫描观察峰形变化可得到比较可靠的结果。30d内4℃条件下,密闭容器中血样接触少量空气不影响其HbCO％的测定。     

Minimally invasive postmortem telebiopsy

For the past 10 years, medical imaging techniques have been increasingly applied to forensic investigations. To obtain histological and toxicological information, tissue and liquid samples are required. In this article, we describe the development of a low-cost, secure, and reliable approach for a telematic add-on for remotely planning biopsies on the Virtobot robotic system. Data sets are encrypted and submitted over the Internet. A plugin for the OsiriX medical image viewer allows for remote planning of needle trajectories that are used for needle placement. The application of teleradiological methods to image-guided biopsy in the forensic setting has the potential to reduce costs and, in conjunction with a mobile computer tomographic scanner, allows for tissue sampling in a mass casualty situation involving nuclear, biological, or chemical agents, in a manner that minimizes the risk to involved staff.     

Human pentastomiasis discovered postmortem

The autopsy of an 18-year-old girl who had died suddenly at home revealed generalised pentastomiasis. The location of this disease in the intestines was responsible for death by hemorrhagic enterocolitis. This discovery constituted an atypical case in our daily practice of forensic medicine.     

Investigation of cardiac troponins in postmortem subjects: comparing antemortem and postmortem levels

The limitations of autopsy in the diagnosis of death due to ischemic heart disease are well known. In the living, a simple reliable biochemical assay for cardiac troponins is used in the diagnosis of acute myocardial ischemia. Several studies have investigated the use of biochemical assays for cardiac troponins in postmortem subjects as a means to distinguish between a cardiac and anoncardiac cause of death. All of these studies, however, rely upon assigning subjects to "cardiac" or "noncardiac" death on the basis of a postmortem examination. As postmortem examination does not always accurately distinguish between these two groups, this approach is intrinsically flawed.Our study compares antemortem and postmortem cardiac troponin levels in five subjects. The antemortem samples were retrieved from the hospital biochemistry laboratory after each subject's death. The postmortem samples for each subject were taken from different sites and at different times during the early postmortem period.Erratic results bearing little or no relation to the antemortem cardiac troponin level were obtained for all subjects. Four of the five subjects had raised antemortem troponin levels, although only one had a cardiac cause of death.From this, we conclude that postmortem blood is not a suitable substrate for standard biochemical assays of cardiac troponins, which are designed for use on serum taken from living patients. In addition, the results of our study support the view that elevated cardiac troponins are a marker of serious morbidity and are not specific for cardiac injury as the primary cause of morbidity or mortality.     

大鼠尸体组织电阻抗的死后变化及与死亡时间的关系

目的探讨躯体组织的电阻抗的死后变化规律，寻找推断死后经过时间的新方法。方法用阻抗测量仪测量大鼠胃壁、腹壁、躯干、胸部、腹部、腹部皮肤、头皮等处不同死后经过时间的电阻抗。结果大鼠躯体组织的电阻抗随着死后经过时间的延长存在规律性变化。这些结果告诉我们，有望通过测量死后人体躯体组织的电阻抗，利用其死后变化规律，推断人体死后经过时间。     

脑组织与其相关分析推断死亡时间的研究进展

推断死后间隔时间(postmortem interval,PMI)一直是法医学鉴定中需要解决的重要问题之一.可用于推断PMI的尸体检材有很多种,脑组织因其独特的解剖学位置与生理功能,是推断PMI的重要检材之一.本文从三个方面将根据脑组织推断PMI的方法进行综述,包括了通过脑组织的温度、形态特点等尸体现象推断PMI;通过...     

Preanalytic aspects in postmortem toxicology

The preanalytic phase has been recognized to have a substantial role for the quality and reliability of analytical results, which very much depend on the type and quality of specimens provided. There are several unique challenges to select and collect specimens for postmortem toxicology investigation. Postmortem specimens may be numerous, and sample quality may be quite variable. An overview is given on specimens routinely collected as well as on alternative specimens that may provide additional information on the route of administration, a long term or a recent use/exposure to a drug or poison. Autolytic and putrefactive changes limit the selection and utility of specimens. Some data from case reports as well as experimental investigations on drug degradation and/or formation during putrefaction are discussed. Diffusion processes as well as postmortem degradation or formation may influence ethanol concentration in autopsy specimens. Formalin fixation of specimens or embalmment of the corpse may cause considerable changes of initial drug levels. These changes are due to alterations of the biological matrix as well as to dilution of a sample, release or degradation of the drug or poison. Most important seems a conversion of desmethyl metabolites to the parent drug. Some general requirements for postmortem sampling are given based on references about specimen collection issues, for a harmonized protocol for sampling in suspected poisonings or drug-related deaths does not exist. The advantages and disadvantages of specimen preservation are shortly discussed. Storage stability is another important issue to be considered. Instability can either derive from physical, chemical or metabolic processes. The knowledge on degradation mechanisms may enable the forensic toxicologist to target the right substance, which may be a major break down product in the investigation of highly labile compounds. Although it is impossible to eliminate all interfering factors or influences occurring during the preanalytic phase, their consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample.     

Linearization of the relationship between postmortem plasma chloride concentration and postmortem interval in rats

A potentiometric titration procedure was employed for measurement of plasma chloride concentrations during the 0-96 h postmortem period in rats. The data revealed antemortem absolute values and postmortem rate of decrease in plasma chloride concentration (PCl) which were almost identical to those in dogs and in man. Expression of the data in the form of a double logarithmic plot of PCl versus postmortem interval (PMI) yielded a linear relationship of high correlation (r = -0.97; P less than 0.001). Attention is drawn to the possibility of utilizing postmortem rate of change in plasma chloride concentration as a means of estimating time elapsed since death.     

Centipede inflicted postmortem injury.

We here report the first case of postmortem injury caused by a centipede. An old man was found dead in his bedroom. The death was estimated to be due to intracranial hemorrhage and to have occurred two days before the police inspection. A centipede about 12 cm long emerged from a subcutaneous cavity on the victim's forearm. Obviously, the centipede had dug the cavity on the intact skin. A police inspector was bitten by the centipede, so he stepped on the centipede on the floor. The exudate from the insect was identified to be derived from the victim's blood.