单体素~1H-MRS推断死亡时间的初步研究

目的检测脑内N-乙酰天门冬氨酸、胆碱复合物及磷酸肌酸和肌酸的变化规律,并探讨其与死亡时间的关系。方法选取12只白兔,利用单体素氢质子磁共振波谱测定死后0.5、1、2、4、6、8、12、16、24h脑内N-乙酰天门冬氨酸、胆碱复合物及磷酸肌酸和肌酸峰下面积;分析其在上述时间点的变化规律,建立与死亡时间相关的回归方程。结果在死后24h内N-乙酰天门冬氨酸、磷酸肌酸和肌酸峰下面积随死亡时间的延长而降低(各时间点比较P<0.05),胆碱复合物在死后24h内无明显变化(各时间点比较P>0.05)。回归方程为:Naa:y=0.7425x2-27.282x+299.984(R2=0.962);Cr:y=0.3234x2-12.007x+210.503(R2=0.986)。结论死后24h内兔脑N-乙酰天门冬氨酸、磷酸肌酸和肌酸呈现出一定的变化规律,其与死亡时间相关程度较高,可用于对一定条件下死亡时间的推断。     

多体素~1H-MRS推断不同温度下死亡时间的研究

目的利用多体素质子磁共振波谱(1H-MRS)技术推断不同温度下的死亡时间。方法选取24只白兔,分为两组,利用多体素质子磁共振波谱测定死后30m in、1h、2h、4h、6h、8h、12h、16h、24h脑内N-乙酰天门冬氨酸、胆碱复合物、磷酸肌酸和肌酸各代谢物之间峰下面积的比值。结果死后24h内N-乙酰天门冬氨酸与磷酸肌酸和肌酸的比值随死亡时间的延长而降低,胆碱复合物与磷酸肌酸和肌酸的比值随死亡时间的延长而升高。Naa/Cr、Ch/Cr与PM I进行回归分析:自变量为Naa/Cr的二次多项式方程为:y=0.0020x2-0.0815x+1.4532(R2=0.971);自变量为Ch/Cr的二次多项式方程为:y=-0.0024x2+0.0870x+1.1876(R2=0.962)。用Naa/Cr的方程推测PM I,当PM I<24h时,平均偏离时间为1.70~50.27m in,用Ch/Cr的方程推测PM I,当PM I<24h时,平均偏离时间为1.12~98.11m in。结论Naa/Cr、Ch/Cr的死后变化与时间呈强相关性,可用于死亡时间推断。     

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.     

多温度下死后心血pH值随时间变化的三维拟合函数研究

目的 探讨通过测量多温度条件下家兔右心血液pH值进行死亡时间推断的可行性.方法 48只家兔随机分为6组,空气栓塞法处死后于10℃、15℃、20℃、25℃、30℃和35℃的不同死亡时间点采集右心血液;用PB-10型pH仪测量样本pH值;SPSS统计软件进行回归分析;MATLAB软件进行数学分析.结果 各温度组右心血液pH值变化与死亡时间呈高度相关(R2=0.974 ～0.982);获得拟合的曲面方程.结论 利用插值函数拟合pH值与死亡时间的曲面方程可进行温度变化条件下的死亡时间推断.     

Time since death. An entomological study on corpses

After death, during disintegration, various environmental conditions and fauna play an important role, indicating "time since death." The natural openings of the host body provide the most important breeding place for an agent which could consume the body very quickly, e.g., flies. Wounds are preferred over the natural openings by this agent. In such cases, antemortem wounds become unidentifiable. This paper presents the study of 25 cases in which inferences relating to the maturation of blow fly life stages and the total developmental time of an adult blow fly in breeding experiments in the prevailing environment are drawn. These can be used to help estimate the "time since death" of infested bodies.     

Heterotopic ossification in unidentified skeletal remains

Heterotopic ossification is a benign, ectopic bone growth that develops in muscle and other soft tissue. The exact cause is poorly understood, but it is a rarely serious complication of soft tissue trauma. Its most common form, myositis ossifications traumatica, occurs as a secondary complication of direct muscle injury. However, other forms are less common and can result from specific pathologic conditions, such as spinal cord trauma and metabolic disorders. In patients who have had spinal cord injury and subsequent paraplegia, heterotopic ossification often results in ankylosis of the hip and a loss in range of motion. Ectopic ossification occurs below the injury site, and, although the specific muscle groups can vary, it usually involves those for which the origin and insertion involve the anterior pelvis and proximal femur. In dried bone, heterotopic ossification can appear as a smooth, irregularly shaped benign tumor of mature bone, extending from the surface but not invading the cortical bone. These tumors range in size from a few millimeters to several centimeters. Because heterotopic ossification is often associated with specific types of injuries, it has a unique anthropological use in forensic cases.     

Evaluation of seven methods of estimating age at death from mature human skeletal remains.

Different approaches to the estimation of age at death in mature human skeletal remains were evaluated utilizing samples from 19 recent French autopsy individuals of known age at death. Methods of estimating age at death from single-rooted teeth, the sternal ends of the fourth ribs, the symphyseal face of the pubis and femoral cortical remodeling were evaluated by two independent observers (three observers for the teeth). Comparison included ages estimated from three more comprehensive approaches utilizing data from the application of two or more of the individual methods. The results indicate that the comprehensive approaches are superior to the individual ones and the success of the latter reflects not only the morphological expression of the aging process, but also the technique complexity and the experience of the investigator. Of the individual techniques, the "Lamendin" dental technique was most effective for individuals of ages greater than 25 years.     

Estimation of the time since death: sudden increase of ambient temperature

This work presents a procedure for the postmortem interval estimation in the presence of a rapid increase of ambient temperature occurred during the cooling phase. The resulting disturbance produced on the cooling curve is proved to obey a two-exponential law and is removed from the actually measured body temperature. This yields a theoretical/modified body temperature, which enables the estimation of the time since death by means of the standard Nomogram method.     

The deployment of conditional probability distributions for death time estimation

The temperature based algorithm known as the Nomogram Method for the determination of a 95.45% death-time interval can be combined with non-temperature based (NTB) findings in the so called Compound Method (CM). The impact of such integration on the probability yielded by the resulting interval has however neither been described nor exploited. In fact the interval after integration of NTB findings rarely yields 95.45% probability. We present a method, based on the conditional probability distribution that can be calculated if the NTB findings are taken into account, which ensures the probability inside the interval to be 95.45%. The method was successfully applied to a set of 53 cases published by Henssge et al. and led to a reduction of the interval width up to more than 15% compared to the CM interval, whereas in other cases the interval width increased due to probability content of the CM intervals below 95.45%. A spreadsheet file in which the method proposed in this paper is implemented can be obtained upon email request from the authors.     

An estimation of the post-mortem interval in human skeletal remains: a radionuclide and trace element approach

Estimation of the post-mortem interval remains a contentious issue, with forensic pathologists often relying upon the recognition of morphological changes.A radionuclide approach has often been suggested in the literature, although limitations have prevented its application, most notably those of diagenesis. Within this pilot study, we show for the first time that there is a correlation between certain radionuclide content and time since death.A larger study is proposed to confirm these findings and possibly provide a calibration against which bones uncovered can be dated.     

Forensic aspects of aboriginal skeletal remains in Australia

The assessment of Aboriginal skeletal remains and their distinction from whites is an area of major importance to the Australian forensic pathologist. The Aborigines, the indigenous people of Australia, are a distinct racial group with many characteristic anthropological features. The assessment of race is best made from an examination of cranial traits, 20 which are of value. A characteristic pattern of attrition of the teeth provides a method for establishing a skeleton as pre-European contact Aboriginal or postcontact tribal Aboriginal. The limb proportions of Aborigines differ significantly from other races and provide a useful adjunct to other racial discriminants. Quantifiable sex discriminants in the Aboriginal pelvis and femur differ in their ranges of values from other races. The humerus and shoulder girdle are of no value in making a racial distinction and are of limited value in sexing Aboriginal skeletons. Some pathological changes seen in Aboriginal skeletons are of value in corroborating race. These pathological changes include evulsion of incisor teeth, healed "parry fractures" of the ulnae, tibial squatting facets, treponemal changes, and auditory exostoses. The place and manner of burial together with related artefacts, features, and ecofacts may also provide corroboration.     

Precision of estimating the time since death by vitreous potassium--comparison of two different equations

The precision of death time estimation by vitreous potassium using two different formulas [1-3] is compared on an independent random sample of 100 cases. The very flat slope in Sturner's equation is the reason for a systematic overestimation of the time since death with much wider 95%-limits of confidence compared to the results using an own equation with a steeper slope of vitreous potassium.     

Strontium-90 as an indicator of time since death: a pilot investigation.

The results of a pilot investigation are presented. The study aimed to show that the presence of radioactive strontium-90 in human bone could be used as evidence of active uptake during life. In this way the time since death of the individual could be identified as occurring before or after the date when atmospheric levels of radioactive strontium were at a peak in the early 1960s. The results of this initial investigation were encouraging but further detailed analysis is required on a substantially larger sample of material spanning a more controlled time period.     

Comparison of four skeletal methods for the estimation of age at death on white and black adults

ABSTRACT: When analyzing human adult skeletal remains, it is often difficult to decide whether a single aging method will give a more reliable age estimation than a combination of methods. This study evaluates four macroscopic indicators for age estimation on 218 American White and Black individuals, ranging in age from 25 to 90 years of age, from the Terry collection. Individuals in the sample were selected to have a balanced race, sex, and age distribution. The following aging methods were applied to each skeleton by one experienced observer: the Suchey–Brooks (SB) pubic symphysis method, the Lovejoy auricular surface method, the monoradicular teeth Lamendin (LM) method, and the I?can (IC) method for fourth ribs. The statistical study involved the evaluation of inaccuracy and bias (based on median age) for each age indicator and the combination of methods using Principal component analysis (PCA). Analysis was performed on the entire sample, then by race, then sex, and then age group (25–40 years, 41–60 years, and >60 years). PCA was the most accurate method for both racial groups when all age groups are analyzed together. When the sample was divided into age groups, SB was the most accurate for young adults (25–40 years) and LM was the most accurate for middle adults (41–60 years). After the age of 60, all methods are highly inaccurate, although IC gives the lowest inaccuracy. As regards bias, the study highlights the tendency of all methods to overestimate the age of young individuals and to underestimate in the older age group. No single skeletal indicator of age at death is ever likely to reflect accurately the many factors that accumulate with chronological age. In fact, one must use as many dental and skeletal indicators as possible. However, in order to maximize the potential of each method, in the final evaluation one should consider mainly the method or methods that have a higher accuracy for a particular age range.     

室外温度与室内恒温下EC随死后经历时间的变化

目的在室外环境和室内恒温条件下测定昼夜不同时间猪后腿肌肉电导率(electrical conductivity,EC)值,分析并比较两种环境条件下,EC值随死后经历时间(time since death, TSD)变化的规律。方法取5块即刻屠宰的猪后腿肌肉,均分为两份,随机分成两组,分别置于秋季室外环境和室内18℃恒温环境中。在死后10d内分别于早晚8时(每隔12h)取样,测定其浸渍液EC值。结果两种环境条件下,EC随TSD变化的趋势在整体上是一致的,二者相关性均较好(R2室外=0.971,P室外=0.004,R2室内=0.98,P室内=0.002)。室外环境温度下,肌肉的EC值在白天增长明显,夜间增长不明显,尤其环境温度低于13℃时,出现明显的平台现象,与室内恒温条件下肌肉EC值持续上升的变化趋势有显著的差异。结论无论室外环境温度还是室内恒温下,肌肉EC与TSD的相关性均较好,但在具体分析时,应考虑到夜间低温平台期造成的时间延搁。