Postmortem changes in resistivity of the anterior abdominal wall during the early postmortem period in rats

An accurate and reproducible technique was employed for the determination of the resistivity of excised portions of the anterior abdominal wall of rats. Resistivity decreased linearly (r = −0.93; P < 0.001) from 1438 ± 131 Ω · cm, immediately following death, to 360 ± 144 Ω · cm at a postmortem interval of 36 h. These changes are believed to reflect the morphological and/or chemical changes which occur at the cellular level during the early postmortem period.     

A preliminary study of changes in scalp impedance during the early post-mortem period in rats.

An accurate and reproducible technique was used for estimation of scalp impedance (1 kHz) in each of eight rat cadavers, maintained at 9.0 +/- 0.7 degrees C, during the 1 to 144 hour post-mortem period. Scalp impedance increased non-linearly, and in a bimodal manner, between 24 and 144 hours post-mortem. The relationship between scalp impedance and post-mortem interval, and the degree of individual variation in the time course of impedance change, were such that scalp impedance is unlikely to be a suitable tool for estimation of time since death.     

Postmortem changes in electrical resistance of the gastric wall during the early postmortem period in rats.

A simple and reliable technique was employed for measurement of (dc) electrical resistance of the gastric wall of rats. Tissue resistance decreased linearly (r = -0.87; P less than 0.001) from 66.1 +/- 12.1 kOhm/cm2 immediately following death to 23.3 +/- 3.5 kOhm/cm2 at a postmortem interval of 24 h. These changes are believed to reflect progressive postmortem changes in the physical dimensions of the intercellular space and/or changes in electrical conductivity of the intercellular/extracellular fluids.     

Release of proteinase inhibitors as a vital reaction in the early post-traumatic interval

In a pilot study paraffin-embedded sections of open skin wounds (stab and slash wounds, lacerations) were investigated to determine the presence of a vital reaction. Granulocytes were detected by naphthol AS-D chloroacetate esterase, the enzyme "lysozyme", and eight proteinase inhibitors by the indirect immunoperoxidase method. The tissue specimens were taken from consecutive autopsy material. The survival time could be determined in 14 cases (10-165 min) and was unknown in 12 other cases of sudden death due to injury of the major vessels or heart. The controls were cases with injuries inflicted after and cases of sudden death due to massive blunt trauma served death. In vital injuries, accumulations of proteinase inhibitors, particularly alpha-2-macroglobulin and alpha-1-antichymotrypsin, were demonstrable in the corium parallel to the wound surface. In comparison, the reaction of proteinase inhibitors that neutralize only enzymes participating in blood coagulation or complement activation (C1-esterase inhibitor and protein C) was absent or weak. Protein accumulation was observed only sporadically in cases of sudden death and never in cases with wounds inflicted after death. No relationship could be established between semiquantitatively estimated staining and survival time. Granulocytes and lysozyme were first observed in the corium after a survival time of more than 60 min.     

Site-dependent production of gamma-hydroxybutyric acid in the early postmortem period

This study compared endogenous gamma-hydroxybutyric acid (GHB) concentrations in various postmortem fluid samples of 25 autopsy cases. All bodies were stored between 10-20 degrees C until autopsy, and the intervals between death and autopsy were less than 2 days (6-48 h). GHB concentrations were measured by headspace gas chromatography after GHB was converted to gamma-butyrolactone. Endogenous GHB concentrations were significantly higher in femoral venous blood (4.6+/-3.4 microg/ml, n=23) than in cerebrospinal fluid (1.8+/-1.5 microg/ml, n=9), vitreous humor (0.9+/-1.7 microg/ml, n=8), bile (1.0+/-1.1 microg/ml, n=9) and urine (0.6+/-1.2 microg/ml, n=12). GHB concentrations were similar in blood samples taken from different sites. Cut-off limits of 30 and 10 microg/ml are proposed for blood and urine, respectively, to discriminate between exogenous and endogenous GHB in decedents showing no or little putrefaction (postmortem intervals usually 48 h or less). The criterion established for endogenous GHB in postmortem urine may also be applicable to analytical results in cerebrospinal fluid, vitreous humor and bile from deceased persons.     

Evaluation of histologic changes of the skin in postmortem period

ABSTRACT: Determination of the time of death is an important consideration in forensic practice. Many methods have been attempted to accurately and systematically determine the postmortem interval (PMI). Histologic examination of the skin or appendages is one of the methods tried by few researchers. However, no attempt had been made to analyze the histologic changes in the skin and appendages simultaneously and to compare them with PMI. We sequentially studied the histologic changes of the skin and appendages in the early PMI. The results of the present study show that the skin undergoes progressive morphological changes in the postmortem period. The epidermis and the dermis appeared normal for 6 hours after death, and after this period, degenerative changes began. By 6 to 9 hours after death, degeneration began in the dermis, and by the end of 18 hours, the dermis began to disintegrate. The sweat glands appeared normal for approximately 3 to 4 hours. For 18 hours after death, the sebaceous glands and hair follicles appeared normal, and after this period, degeneration began.     

The use of absolute refractory period in the estimation of early postmortem interval

The estimation of the time since death (postmortem interval) is one of the most difficult problems in forensic pathology. Most methods currently employed use temperature-based algorithms intended to model the cooling of the body after death and thus estimate the postmortem interval. These methods are subject to considerable inaccuracy but their reliability can be improved if a range of other observed criteria such as lividity and rigor are also taken into consideration. The aim of the present study was to investigate the feasibility of using the absolute refractory period as an adjunct to the estimation of postmortem interval. The relationship between the `postmortem interval' and the `duration of absolute refractory period' was investigated using the rat sciatic nerve. A strong correlation between the duration of the absolute refractory period and the postmortem interval was observed. When both absolute refractory period and temperature were used in conjunction, the strength of this correlation was increased.     

多层螺旋CT、普通CT和X线在骨折法医学鉴定中的应用

目的比较多层螺旋CT（MSCT）、普通CT与X线3种检查法,评价它们在骨折法医鉴定中的应用价值。方法对366例受检者（已接受其他影像学检查）行MSCT薄层扫描并行SSD,透明化X线模拟投影和MPR处理。统计分析MSCT、CT常规与X线检查在各部位骨折中的诊断正确率和漏、误诊率并行χ2检验。结果鼻骨、肋骨、四肢及关节、眶骨、颅骨骨折MSCT诊断正确率明显高于普通CT或X线（P〈0.01）。MSCT与普通CT对脊柱骨折的诊断正确率无统计学差异（P〉0.05）。MSCT、普通CT与X线的总体诊断正确率分别为99.45%、70.27%和59.17%。常规CT、X线与MSCT诊断结果间存在显著统计学差异（P〈0.001）。结论MSCT对骨折的显示更准确,可作为法医鉴定的重要辅助检查手段。     

Characteristics of blood circulation in the lungs during the early period after blunt multiple trauma

The microscopic and histostereometric examinations of specific features of blood circulation in the lungs (in lethal cases) performed during the early period after combined trauma showed pronounced disturbances of blood circulation in body organs which had a certain sequence in the development of vascular reactions and vascular temporal dynamics. The influence of a preceding alcoholic intoxication and intensive hemorrhage on the circulatory dynamics was demonstrated.     

Interleukin-6 and C-reactive protein serum levels in sepsis-related fatalities during the early postmortem period

Postmortem interleukin-6 (IL-6) and C-reactive protein (CRP) serum levels were investigated prospectively in sepsis-related fatalities and non-septic fatalities by using a linear regression model. At least three blood samples were collected between 0.3 and 139 h postmortem from sepsis-related fatalities (n=8) and non-septic fatalities (n=16). In addition, one antemortem blood sample was collected shortly before death from the septic patients. Antemortem and postmortem IL-6 and CRP levels were highly elevated in all individuals included in the sepsis group. An excessive postmortem increase of IL-6 serum levels associated with progressive time after death was observed in five out of the eight septic patients. Both, IL-6 and CRP serum concentrations seem to be suitable biochemical postmortem markers of sepsis. The determination of IL-6 serum levels above 1500 pg/ml in peripheral venous blood obtained in the early postmortem interval can be considered as a diagnostic hint towards an underlying septic condition. A more precise postmortem discrimination between sepsis and non-septic underlying causes of death is provided by the postmortem measurement of serum CRP in peripheral venous blood: on condition that at least two postmortem CRP values have been determined at different time points postmortem, the CRP level of a deceased at the time of death can be calculated by using linear regression analysis. When assessing postmortem IL-6 and CRP concentrations as biochemical postmortem markers of sepsis, various clinical conditions, such as a preceding trauma or burn injury going along with elevated IL-6 and/or CRP levels prior to death as a result of the systemic inflammatory response syndrome (SIRS) should be taken into consideration, thus adding relevant information for the practical interpretation of the results.     

家兔死后离体血液ATP含量变化与放置时间的关系

目的探讨恒温(25℃)条件下家兔死后离体血液ATP含量变化与放置时间的关系。方法健康家兔8只,空气栓塞处死后即刻取右心室血液,置于25℃恒温水浴槽中,每4h应用ATP荧光快速检测仪检测血液ATP含量,所得数据应用SPSS17.0统计学软件进行方差检验及回归分析。结果恒温(25℃)环境下,家兔死后离体血液的ATP含量,在8h内从死后即刻的2.46×10-12mol/L升至3.09×10-12mol/L,8h之后则随PMI的延长而下降,直至56h,56～72h ATP含量在0.13×10-12mol/L时趋于稳定。以Log[ATP]为因变量(y),离体放置时间为自变量(x),对死后0～56h的数据进行回归曲线分析,建立了3个推断离体时间方程,即y=-0.019x-11.359(R2=0.763)、y=0.001x2+0.016x-11.666(R2=0.962)和y=-1.281×10-5x3-0.007x-11.576(R2=0.980),其中三元回归方程的系数为0.980,曲线拟合度最好。结论家兔离体血液ATP含量变化与放置时间呈现一定的规律性,有望应用于死亡时间推断。