Wendt-Gallitelli M F, Stöhr P, Wolburg H, Schlote W
Scan Electron Microsc. 1980(Pt 2):499-509.
Heart muscle preparations (papillary muscles and trabeculae) were frozen at 4.2 K on metal plate under vaccum after their length-tension relationships showed that no damage had occurred during dissecting and mounting the strips on the holder. Freeze substitution of some preparations directly after freezing demonstrated that no important cell damage due to ice crystals occurred in superficial cell layers during freezing. Ultrathin cryosections obtained at -130 degrees C were freeze dried and analyzed, in the STEM mode. The better the freezing procedure, the poorer was the contrast of the sections under electron microscopy. Preliminary approaches to increasing contrast after sublimation of tissue water show that a small increase in contrast is generally obtained at the cost of the peak/background ratio due to pronounced mass loss. The results of our analyses show that C1 content in heart muscle cells is high and distributed throughout the cytoplasm. Ca is detectable and quantitable in resting muscle in SR cisternae. The Ca amount in cytoplasm is low and just at the limit of detectability under our current analysis conditions. Preliminary experiments on papillary muscles subjected to caffeine contracture showed that calcium is not detectable in the cisternae as is the case in control experiments. Only a moderate amount of Ca is detectable in mitochondria, whereas the concentrations in cytoplasm, as in resting cardiac muscle, is too low to be quantitated.
在心肌标本（乳头肌和小梁）的长度-张力关系表明在解剖和将标本安装到固定器上的过程中未发生损伤后，将其在真空中于金属板上冷冻至4.2K。对一些冷冻后直接进行冷冻置换的标本进行研究，结果表明在冷冻过程中，表层细胞层未因冰晶形成而发生严重的细胞损伤。在-130℃下获得的超薄冷冻切片经冷冻干燥后，采用扫描透射电子显微镜（STEM）模式进行分析。冷冻过程越好，电子显微镜下切片的对比度就越差。在组织水分升华后增加对比度的初步方法表明，由于明显的质量损失，对比度虽有小幅增加，但通常是以峰/背景比为代价的。我们的分析结果表明，心肌细胞中的C1含量很高，且分布于整个细胞质中。在静息肌肉的肌浆网中可检测到钙并进行定量分析。在我们目前的分析条件下，细胞质中的钙含量很低，仅处于可检测的极限。对经历咖啡因挛缩的乳头肌进行的初步实验表明，与对照实验不同，在肌浆网中无法检测到钙。在线粒体中仅可检测到适量的钙，而细胞质中的浓度与静息心肌一样，过低而无法进行定量分析。
