References for determining the time of death by potassium in vitreous humor

The different statements concerning the slope and intercept of the regression line and the 95% limits of confidence are the reason that potassium in vitreous humor is not used (at least in Germany) as an aid in estimating the time of death. The relationship between the concentration of potassium and the time of death is mainly influenced by antemortem electrolyte imbalances caused by disease and/or duration of terminal episode. The influence of terminal episode is best identified by its duration (Adelson et al., J. Forensic Sci., 8 (1963) 503-514). In order to have a method suitable for every case and to be as precise as possible we looked therefore for parameters in vitreous humor which were stable postmortem and indicating antemortem electrolyte imbalance. Urea is such a parameter, being stable postmortem (Coe, Am. J. Clin. Pathol, 51 (1969) 741-750) and useful as a marker of antemortem electrolyte imbalance. Our investigations on potassium in vitreous humor, including sudden and hospital deaths after chronic lingering disease, revealed 95% limits of confidence of +/- 34 h up to 120 h postmortem. Reviewing only cases with urea less than 100 mg/dl the 95% limits of confidence could be reduced to +/- 22 h. Considering the duration of terminal episode (less than 6 h) the precision was +/- 20 h. In this way our modified procedure is suitable for every case with the resulting precision of estimation being determined only by the duration of the terminal episode and urea concentration.     

References for determining the time of death by potassium in vitreous humor

The different statements concerning the slope and intercept of the regression line and the 95% limits of confidence are the reason that potassium in vitreous humor is not used (at least in Germany) as an aid in estimating the time of death. The relationship between the concentration of potassium and the time of death is mainly influenced by antemortem electrolyte imbalances caused by disease and/or duration of terminal episode. The influence of terminal episode is best identified by its duration (Adelson et al., J. Forensic Sci., 8 (1963) 503–514). In order to have a method suitable for every case and to be as precise as possible we looked therefore for parameters in vitreous humor which were stable postmortem and indicating antemortem electrolyte imbalance. Urea is such a parameter, being stable postmortem (Coe, Am. J. Clin. Pathol., 51 (1969) 741–750) and useful as a marker of antemortem electrolyte imbalance. Our investigations on potassium in vitreous humor, including sudden and hospital deaths after chronic lingering disease, revealed 95% limits of confidence of ±34 h up to 120 h postmortem. Reviewing only cases with urea less than 100 mg/dl the 95% limits of confidence could be reduced to ±22 h. Considering the duration of terminal episode (<6 h) the precision was ±20 h. In this way our modified procedure is suitable for every case with the resulting precision of estimation being determined only by the duration of the terminal episode and urea concentration.     

Methodological questions in resolving the problem of determining the time of death]

Presents the modern concept of evaluating the time of death, the philosophy of solving this problem, and approaches to its solution. Analyzes the procedure and choice of correct approach to problem solution from methodological viewpoint and as a problem at the interface of medicine and technology.     

胃内容推断死亡时间的误差(附2例报告)

尽管有许多推断死亡时间的方法,但运用胃内容消化和排空情况推断死亡时间简单易行,具有相当重要的实践意义.在法医学教科书中,运用胃内容消化和排空情况推断死亡时间已有论述.一般说来,食后不久即死亡者, 胃内容移向十二指肠,约在食后2～3h;胃、十二指肠均已空虚,则死亡可能发生在食后6h以上[1].但在实际检案中,有时我们感到运用胃内容消化和排空情况推断餐后死亡时间,与书中提供的时间相差较大.现对本地区两例凶杀案件根据教科书介绍的胃内容推断死亡时间方法造成错误推断,谈谈我们的体会.     

Wildlife forensic entomology: determining time of death in two illegally killed black bear cubs.

Forensic entomology is now commonly used to determine time of death in human death investigations. However, it can be equally applicable to wildlife crimes. This paper describes the use of entomology to determine time of death in the illegal killing of two young bear cubs in Manitoba, Canada. Two cubs were found shot, disemboweled, with their gall bladders removed. Natural Resource officers (Conservation Officers) and a Royal Canadian Mounted Police (R.C.M.P.) officer examined the remains, and the R.C.M.P. officer collected insect evidence. The only insects on the remains were adult blow flies coming to lay eggs and the blow fly eggs themselves (Diptera: Calliphoridae). The time of hatch was recorded and the insects were reared to adulthood. Time of hatch, together with species identification, macro and micro climate and lab developmental data were used to determine the time of death. The time was consistent with the time that the defendants were seen at the scene and was used in their conviction. This case illustrates that insect evidence can be equally as valuable in poaching cases as in homicide cases. However, in most cases Conservation Officers are unaware of this science. It is therefore, extremely important for more Conservation Officers to be educated about this field.     

Determination of the time of death in a homicide-suicide case using flow cytometry.

The study of the biologic processes involved in determining the postmortem interval also can be useful for determining the time of death. In this instance, we investigated the time of death in a case of homicide-suicide using circumstantial findings and thanatochronological and flow cytometric data. The flow cytometric data confirmed the time of death as calculated from the police investigations. This method has proven more reliable than thanatochronological techniques and can be used to supplement these observations. This case indicates that the use of flow cytometry "on the spot" is useful and reliable; however, more evidence is needed to support this new, although to date very sound, method of investigation.     

脑温死亡时间测定仪的研制

目的研制脑温死亡时间测定仪。方法根据动物和尸体实验了解脑温下降的规律,并选择针状温度传感器,确定测温入径途径。结果针状传感器的优点是:快速敏感、准确性高、对组织破坏少、插入方便。尽管这种方法仍有误差,但它与现在法医学上常用的方法相比误差已减少了许多。结论所研制的死亡时间测定仪具有体积小,便于携带、探头灵敏,可以迅速方便地探测死者的脑温,并能直接推断死亡时间,避免了某些人为的因素造成的误差。     

A suicide using a homemade carbon monoxide "death machine"

Deaths related to carbon monoxide (CO) poisoning are common. Most represent accidents and suicides, and most result from CO production via the incomplete combustion of carbon-containing substances. Suicide via CO toxicity is not uncommon and typically involves the use of motor-vehicle exhaust as a source of CO. Presented herein is a case of suicidal CO poisoning in which the CO was produced via a chemical reaction between formic acid and sulfuric acid within a homemade device.     

Estimation of the time since death

The main principle of the determination of the time since death is the calculation of a measurable date along a time-dependent curve back to the start point. Characteristics of the curve (e.g. the slope) and the start point are influenced by internal and external, antemortem and postmortem conditions. These influencing factors have to be taken into consideration quantitatively in order to improve the precision of death time estimation. It does not make any sense to study the postmortem time course of any analyte without considering influencing factors and giving statistical parameters of the variability. Comparison of different methods requires an investigation of the same postmortem interval. For practical purposes, it must be concluded that the amount of literature on estimating the time since death has a reverse correlation with its importance in practice.     

Determination of the time of death according to rectal thermometry data using computer calculations

A mathematic model of estimation of time of death (TD) in newborns is proposed. This computer method of TD timing by changes of body temperature differs from earlier developed mathematical models by possibility to consider individual anthropometric and thermophysical characteristics of the body. It is more precise, shorter and easy to perform.     

Preliminary study on using changes in astrocytes and neurons in the brain-stem of the rat after stab wounds for determining the time of injury

The changes in astrocytes and neurons in the brain-stem of the rat after stab wounds were studied immunohistochemically. Anti-GFAP and anti-albumin antibodies were used to detect the changes of astrocytes and neurons, respectively. The results showed that in normal control group, the numbers of GFAP-positive cells differed in different areas of brain-stem, but remained similar in the same area of different rats. No albumin-positive cells could be found. The number of GFAP-positive cells in antemortem injury groups increased significantly followed by a decrease, and then a further increase. Albumin-positive cells including neurons and glial cells were found after injury in the midbrain, pons and medulla oblongata. In the postmortem injury groups, there were no significant changes in either anti-GFAP or anti-albumin immunoreactivities in any area of brain-stem compared to the control group. These results indicated that the changes in the number of GFAP-positive cells could be used to estimate the time of injury and to diagnose early brain-stem injury. The antemortem and postmortem injuries can also be differentiated by the presence of albumin-positive cells. The authors suggest that the timing and early diagnosis of injury in the brain-stem should be carried out on the basis of comprehensive analyses of changes in both neurons and glial cells.