Sub-microscopic analysis of t-tubule geometry in living cardiac ventricular myocytes using a shape-based analysis method.
Sub-microscopic analysis of t-tubule geometry in living cardiac ventricular myocytes using a shape-based analysis method.
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DOI：
10.1016/j.yjmcc.2017.05.003
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发表时间：
2017-07
影响因子：
5
通讯作者：
Cannell MB
中科院分区：
文献类型：
--
作者：
Kong CHT;Rog-Zielinska EA;Orchard CH;Kohl P;Cannell MB
横轴小管（TT）是参与心脏兴奋-收缩偶联的关键结构，并且可以在疾病中变得紊乱。虽然TT的光学测量经常用于评估TT丰度和规律性，但TT尺寸通常低于光学显微镜的衍射极限，因此小管尺寸的测定是有问题的。TT直径通过用荧光探针（分别为FM 4 -64和钙黄绿素）标记局部表面膜面积和体积，通过图像处理校正图像不对称性并使用表面积和体积之间的关系作为几何图元来测量。该方法显示TT在兔中具有356 ± 18 nm的平均（± SEM）直径，在小鼠中具有169 ± 15 nm的平均（± SEM）直径（p < 0.001）。兔TT直径的变异性大于小鼠（p < 0.01），小鼠TT最小为41 nm，兔TT最大为695 nm。这些估计是一致的TT直径来自更有限的采样高压冷冻样品的电子断层扫描（检查只有一小部分的细胞体积）。TT丰度和几何形状（如体积，膜分数和方向）的其他措施也得到了。在E-C耦合的生理时间尺度（毫秒）上，平均TT电空间常数在兔中为~ 175 μm，在小鼠中为~ 120 μm，约为稳态空间常数的50%。这足以确保正常电池之间的合理电均匀性。图像处理策略和基于形状的3D特征量化方法通常也适用于亚细胞解剖结构量化中的其他问题。用荧光表面和体积探针对活心肌细胞进行双标记。一种新的3D图像处理策略能够计算t-小管直径。该方法显示兔和小鼠的t-小管具有非常不同的形态。兔和小鼠t-小管的平均直径分别为360和170 nm。估计的电空间常数足以确保电均匀性。
Transverse-axial tubules (TTs) are key structures involved in cardiac excitation-contraction coupling and can become deranged in disease. Although optical measurement of TTs is frequently employed to assess TT abundance and regularity, TT dimensions are generally below the diffraction limit of optical microscopy so determination of tubule size is problematic. TT diameter was measured by labeling both local surface membrane area and volume with fluorescent probes (FM4-64 and calcein, respectively), correcting image asymmetry by image processing and using the relationship between surface area and volume for a geometric primitive. This method shows that TTs have a mean (± SEM) diameter of 356 ± 18 nm in rabbit and 169 ± 15 nm in mouse (p < 0.001). Rabbit TT diameters were more variable than those of mouse (p < 0.01) and the smallest TT detected was 41 nm in mouse and the largest 695 nm in rabbit. These estimates are consistent with TT diameters derived from the more limited sampling of high-pressure frozen samples by electron tomography (which examines only a small fraction of the cell volume). Other measures of TT abundance and geometry (such as volume, membrane fractions and direction) were also derived. On the physiological time scale of E-C coupling (milliseconds), the average TT electrical space constant is ~ 175 μm in rabbit and ~ 120 μm in mouse and is ~ 50% of the steady-state space constant. This is sufficient to ensure reasonable electrical uniformity across normal cells. The image processing strategy and shape-based 3D approach to feature quantification is also generally applicable to other problems in quantification of sub-cellular anatomy. Living cardiomyocytes were dual-labeled with fluorescent surface and volume probes. A novel 3D image processing strategy enabled calculation of t-tubule diameter. The method shows rabbit and mouse t-tubules have quite different morphologies. Mean diameters of rabbit and mouse t-tubules were 360 and 170 nm, respectively. Estimated electrical space constants are sufficient to ensure electrical uniformity.
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影响因子：
3.7
作者：
Crossman DJ;Ruygrok PN;Soeller C;Cannell MB
通讯作者：
Cannell MB
影响因子：
82.9
作者：
通讯作者：
--
影响因子：
3
作者：
Kremer, JR;Mastronarde, DN;McIntosh, JR
通讯作者：
McIntosh, JR
DOI：
10.1111/j.1749-6632.1998.tb08253.x
发表时间：
1998-01-01
期刊：
CARDIAC SARCOPLASMIC RETICULUM FUNCTION AND REGULATION OF CONTRACTILITY
影响因子：
--
作者：
Franzini-Armstrong, C;Protasi, F;Ramesh, V
通讯作者：
Ramesh, V
影响因子：
9.7
作者：
Dibb, Katharine M.;Clarke, Jessica D.;Trafford, Andrew W.
通讯作者：
Trafford, Andrew W.