AN IMPROVED APPARATUS FOR THE OPTICAL-RECORDING OF CONTRACTION OF SINGLE HEART-CELLS
AN IMPROVED APPARATUS FOR THE OPTICAL-RECORDING OF CONTRACTION OF SINGLE HEART-CELLS
复制标题
DOI：
10.1007/bf00582531
复制
发表时间：
1988-12-01
影响因子：
4.5
通讯作者：
ORCHARD, CH
中科院分区：
文献类型：
--
作者：
BOYETT, MR;MOORE, M;ORCHARD, CH
描述了一种用于测量心肌细胞在无负荷收缩期间细胞长度变化的光学系统。一个一维的视频“图像”的细胞获得每4毫秒与线性光电二极管阵列，这是与细胞的纵轴对齐。用于处理来自光电二极管阵列的图像的电路具有多种特征以帮助精确确定单元的端部之间的距离，即，细胞的长度。首先，细胞的视频图像被分成两个“窗口”，一个包含细胞的“前”边缘，另一个包含“后”边缘。排除超出细胞边缘的其他细胞或碎片。一般光水平的变化，例如由于漂浮在细胞上方的碎片，几乎没有影响，因为在窗口内，“背景光水平”在信号被进一步处理之前被从信号中减去。为了检测小区边缘，系统确定窗口内的信号何时超过（前边缘）或下降到（后边缘）所选阈值以下，所选阈值对于前边缘和后边缘是不同的。该系统具有“记忆”，它将细胞的后边缘识别为信号福尔斯最后一次下降到阈值以下;因为细胞内的“亮点”不会被误认为是细胞的末端。该系统具有“滞后”，使其能够忽略阈值附近亮度的小波动。该系统易于使用、精确、易于校准，并且具有良好的空间和时间分辨率（分别约为0.25 μ m和4 ms）。
An optical system for measuring changes in cell length during unloaded contractions of cardiac myocytes is described. A one-dimensional video "image" of a cell is obtained every 4 ms with a linear photodiode array, which is aligned with the longitudinal axis of the cell. The circuit used to process the image from the photodiode array has a variety of features to aid in the accurate determination of the distance between the ends of the cell, i.e., the cell length. First, the video image of the cell is divided into two "windows", one encompassing the "front" edge of the cell, the other encompassing the "rear" edge. Other cells or debris beyond the cell edges are excluded. Changes in the general light level, for example as a result of debris floating above the cell, have little effect because within the windows the "background light level" is subtracted from the signals before they are processed further. To detect the cell edges, the system determines when the signals within the windows exceed (front edge) or drop below (rear edge) chosen thresholds, which are different for the front and rear edges. The system has "memory" and it identifies the rear edge of the cell as the last time the signal falls below the threshold; because of this "bright spots" within the cell are not mistaken for the end of the cell. The system has "hysteresis", which enables it to ignore small fluctuations in brightness around the threshold. The system is easy to use, accurate, readily calibrated, and it has good spatial and time resolution (about 0.25 .mu.m and 4 ms respectively).