Magnetic Resonance Spectroscopy of Rat Skeletal Muscles. An Application to the Estimation of the Postmortem Interval.

人们认为，ATP含量的下降与僵直死亡的发生有直接关系。因此，骨骼肌中的ATP含量被认为是估计死后死亡的一个有价值的因素。然而，使用常规技术很难准确地定量生物材料中的高磷化合物。~(31)P-MRS可用于快速、无创地测定生物组织中的三磷酸腺苷、磷酸肌酸和无机磷。细胞内pH值也可以用等电点的化学位移来确定。光谱的操作和解释相对简单，因此很容易掌握技术。为了评估应用~(31)P-MRS估计死后时间的可能性，我们使用~(31)P-MRS分析了死亡大鼠骨骼肌中的高能磷酸盐化合物，并检验了分析结果与p…之间的关系。更多的死亡间隔。这些动物是在勒死、氮气窒息、溺水或一氧化碳、甲基苯丙胺、可卡因、乙醇或氯化钾中毒致死的情况下被杀的。在死亡后4小时内，使用表面线圈技术进行P-MRS检查。计算了光谱峰的信号强度和组织中的pH值。用相关分析估计死后间隔时间与组织中的三磷酸腺苷、聚合酶链式反应和PI含量以及pH值之间的关联强度。回归分析也被用于从31&gt；P-MRS数据估计死亡时间间隔。在任何一种杀伤模式中，随着死亡时间的延长，PCR值和ATP值下降，而PI值上升。PH值在死后早期呈线性下降。在死前肌肉活动相对缺乏的大鼠组织中，PCR值和ATP含量的下降相对较慢。当大鼠在剧烈运动、挣扎或惊厥后死亡时，PCR值和ATP含量的下降速度加快。在各种杀灭方式中，pH值下降率变化不大。在任何致死方式中，所有的P-MRS数据均显示与死亡时间显著相关。组织中的pH值与死后时间有密切关系。最小二乘回归分析从31&gt；P-MRS数据估计死亡时间间隔是成功的。计算的R平方值很高，尽管数据点显示出一定程度的离散性。我们目前的结果表明，P-MRS数据可以作为估计死亡时间的一种手段。特别是，在死亡的早期阶段，pH值通常被认为是估计死亡时间的最可靠的方法之一。较少

It is considered that the fall in ATP content is directly related to the onset of rigor mortis. Therefore, ATP content in the skeletal muscle is a factor which has been considerd to be of value in estimating the postmortem intaerval. Using conventional techniques, however, it is difficlt to quantify high phosphate compounds accurately in the biological materials. The ^<31>P-MRS can be used to measure ATP,phosphocreatine (PCr) and inorganic phosphate (Pi) very rapidly and noninvasively in biological tissues. Intracellular pH value can also be determined using the chemical shift of Pi. The operation and the interpretation of the spectrum is relatively simple, so it is easy to master the technique. For the purpose of evaluate the possibility of the application of ^<31>P-MRS to the estimation of the postomortem interval, we analyzed high energy phosphate compounds in the skeletal muscles of the dead rats using the ^<31>P-MRS and examined the association between the analytical results and p … More ostmortem intervals. The animals were killed in cases of strangulation, nitrogen asphyxia, drowning, or fatal intoxications due to CO gas, methamphetamine, cocaine, ethanol or KC1. ^<31>P-MRS was performed using the surface coil technique up to 4 hours after death. Signal intensities of the peaks in the spectra and the pH values in the tissues were calculated. Correlation analysis was used to estimate the strength of the association between the postmortem interval and the content of ATP,PCr and Pi, and the pH value in the tissues. Regression analysis was also used to estimate the postmortem interval from ^<31>P-MRS data. In any mode of killing, PCr and ATP decreased after death, whereas Pi increased with time. The pH value was decreased linearly in the early stage after death. In the tissues of the rats killed in the relativeabsence of muscular activity before death, the reduction of the PCr and ATP content was relatively slow. When the rats died following hard exercise, struggle or convulsions, the fall in PCr and ATP content was accelerated. Among all the mode of killing, there was little variation in the decreasing rate of the pH value. In any mode of killing, all ^<31>P-MRS data indicated significant correration with postmortem interval. There was a close relation between the pH in the tissue and postmortem interval. Least squares regression analysis to estimate the postmortem interval from the ^<31>P-MRS data was successful. R squared values calculated were high, althogh the data points showed some degree of scatter. Our present results suggest that ^<31>P-MRS data can be used as a means to estimate the time of death. Especially, in the early stage after death, the pH value is generally ragarded as providing one of the most reliable ways of estimating the time of death. Less