目的 探索在不同环境温度条件下,玻璃体液中钾离子浓度变化规律与死亡时间的关系.方法 家兔处死后分别置于5℃、15℃、25℃和35℃温度下保存,在0~120h内每12h双眼交替微量提取玻璃体液80~100μL;应用罗氏DPPI生化分析仪检测玻璃体液中K+的浓度;应用插值函数进行分析拟合,建立死亡时间推断方程.结果 各温度组家兔玻璃体液中K+浓度随死亡时间延长均呈上升趋势,对所得数据进行插值拟合,在5℃~35℃的温度变化区间内,K+浓度变化与PMI关系的三元五次曲面方程:f(x,y)=-1.998e14+1.345e12x+5.902e13y+0.005585x2-4.509e11xy-3.876e12y2-0.0002868x3+0.003545x2y+4.406e10xy2-1.746e10y3+2.669e-6x4-1.568e-5x3y-0.0001771x2y2-1.64e9xy3+6.669e9y4-8.672e-9x5+4.467e-8x4y+2.354e-7x3y2+2.459e-6x2y3+2.05e7xy4-1.214e8y5(R2=0.9956),其中温度为自变量x,K+浓度值为自变量y,PMI为因变量f(x,y).结论 在5℃~35℃的环境温度区间内,家兔眼玻璃体液中K+浓度变化与死亡时间关系符合三元五次方程分布,利用插值函数拟合的方法可将环境温度作为参数,实现在环境温度变化条件下进行死亡时间推断.%Objective To investigate the relationship between K+ concentration in rabbit vitreous humor and postmortem interval (PMI) under different ambient temperature. Methods Rabbit corpses were stored at 5℃ , 15℃ , 25℃ , and 35℃ after execution, and 80~100μL vitreous humor was extracted from each eye of the rabbit in turn every 12 hours. The concentrations of K+ were examined by Modular DPPI automatic biochemistry analyzer. The Interpolation Functions were used to analyze the statistical relationship between PMI and K+ concentration under different temperature. Results In each animal group, K+ concentration increased with PMI. Equation was obtained after interpolation analysis on range of temperature 5℃ ~30℃ . The three-variable quintic surface equation was f(x,y)=-1.998e14+1.345e12x+5.902e13y+0.005585x2-4.509e11xy-3.876e12y2-0.0002868x3+0.003545x2y+4.406e10xy2-1.746e10y3+2.669e-6x4-1.568e-5x3y-0.0001771x2y2-1.64e9xy3+6.669e9y4-8.672e-9x5+4.467e-8x4y+2.354e-7x3y2+2.459e-6x2y3+2.05e7xy4-1.214e8y5(R2=0.9956), x stands for temperature, y stands for K+ concentration, f(x,y) stands for PMI. Conclusion The rule of K+ concentration changes at ambient temperature complied with three-variable quintic surface equation distribution. Measurement of interpolation function may be used for PMI estimation at different ambient temperature.
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