IMPROVED ANALYSIS OF ELECTRON-MICROSCOPIC AUTORADIOGRAMS

拟议工作的广泛目标是实施和推广新的 电子显微镜放射自显影(EMA)分析方法 可广泛提供给生物医学研究人员。新方法 已在仿真和实际数据中得到普遍应用。新方法是 基于统计的最大似然方法，并使用 期望最大化算法，这导致递归方程 在最初的公式中，对计算要求太高，不能 适用于传统计算机。最新的改装 算法使其在小型PC级计算机上具有计算实用性 实验室调查人员一般都能得到。 具体目标是：(1)在小型计算机上实施新方法 一种通用形式，可由广泛的通常 可用的机器，并提供给全国社区；(2)开发 EMA模拟器，它使用实验数据来产生每个 成套显微照片分析--可靠性的统计量度 所产生的估计值，以及作为实用程序的 建立测试所需的实验要求 生物学假说；(3)确定基本解析力 点扩散的方法及其受影响因素的影响 不同的放射性同位素；以及(4)开发自动电磁成像 为了减少繁琐的分割(结构描述)方法 这是当前手动数据采集方法所固有的。 新方法的意义在于，与交叉火力相比 方法(1)它产生的示踪剂浓度估计值要大得多 精确度，(2)它能够产生具有生物意义的结果 更少的EM图像和/或更低的放射性水平，(3)它 保证了最大似然估计的全局收敛，从而 消除了对特殊的“轮缘隔间”的需要。新事物的力量 该方法已在肌膜摄取的研究中得到证实 花生四烯酸通过损伤的心肌细胞，这产生了对 缺血性心肌损伤的发病机制。

The broad goal of the proposed work is to implement and extend a new method for electron-microscopic autoradiographic (EMA) analysis so that it can be made widely available to biomedical investigators. The new method has been shown in simulation and real-data general use. The new method is based on the maximum-likelihood method of statistics and uses the expectation-maximization algorithm, which leads to recursive equation that was, in its original formulation, too computationally demanding to be practical for conventional computers. Recent reformulations of the algorithm render it computationally practical on small PC-class computers generally available to laboratory investigators. Specific aims are: (1) to implement the new method for small computers in a generalized form that can be accommodated by a wide range of commonly available machines, and offer it to the national community; (2) to develop an EMA simulator which uses the experimental data to produce with every analysis of sets of micrographs, a statistical measure of the reliability of the estimates produced, and which functions as a utility for establishing the experimental requirements necessary for testing biological hypotheses; (3) to determine the fundamental resolving power of the method and how it is influenced by factors affecting point-spread for different radio-isotopes; and (4) to develop an automated EM-image segmentation (structure delineation) method in order to reduce the tedium inherent in current manual methods for data acquisition. The significance of the new method is that in comparison to the cross-fire method (1) it yields estimates of tracer concentrations with much greater accuracy, (2) it is able to produce biologically meaningful results from far fewer EM images and/or at much lower levels of radioactivity, (3) it guarantees global convergence on the maximum-likelihood estimate, thereby eliminating the need for ad hoc "rim compartments." The power of the new method has been demonstrated in a study of sarcolemmal uptake of arachidonic acid by injured myocytes, which has yielded new insights into the pathogenesis of ischemic myocardial injury.