Computerized curve fitting in the analysis of hydrogen gas clearance curves.
Computerized curve fitting in the analysis of hydrogen gas clearance curves.
复制标题
氢气清除率曲线分析中的计算机曲线拟合。
DOI：
10.1152/ajpgi.1989.257.4.g668
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Guth,PH
中科院分区：
文献类型：
--
作者：
Livingston,EH;Reedy,T;Leung,FW;Guth,PH
将大鼠胃体的氢气清除率曲线数字化到计算机中，采用对数变换数据的线性回归、改进的高斯-牛顿非线性回归算法的直接曲线拟合和Zierler的高度/面积算法进行分析。对于对数变换数据的线性回归，如果初始基线估计不准确或存在正常量的实验噪声，则对数变换数据偏斜，导致回归线偏离，导致血流量估计不正确。使用直接拟合程序，由于参数的迭代改进，参数的初始估计或实验噪声对血流测定的影响很小。在一项异丙肾上腺素刺激胃血流量的研究中，Zierler的算法低估了血流量的估计值。我们得出结论，通过对数变换数据的线性回归或Zierler算法分析氢气间隙曲线可能会在血流估计中引入误差，而使用直接拟合的非线性回归算法可以避免这种误差。
Hydrogen gas clearance curves obtained from the rat gastric corpus were digitized into a computer and then analyzed by three methods: 1) linear regression of log-transformed data, 2) direct curve fitting with a modified Gauss-Newton nonlinear regression algorithm, and 3) Zierler's height-over-area algorithm. For linear regression of log-transformed data, if the initial base-line estimate was inaccurate or normal amounts of experimental noise were present, the log-transformed data was skewed, leading to deviation of the regression line and incorrect estimation of blood flow. By utilization of the direct-fit routine, the initial estimate of the parameters or experimental noise had little influence on the blood flow determination because of iterative improvement of the parameters. In a study of isoproterenol-stimulated gastric blood flow, Zierler's algorithm underestimated the blood flow estimate. We conclude that analysis of hydrogen gas clearance curves by linear regression of log-transformed data or by Zierler's algorithm may potentially introduce errors in blood flow estimates that may be avoided by analysis with a direct-fitting, nonlinear regression algorithm.