Pexieder T
Scan Electron Microsc. 1981(Pt 2):223-53.
The chronology of SEM studies of the embryonic endocardium is followed in this review by discussion of species, stages and localizations studied. In reviewing the methodology of SEM studies of the embryonic endocardium, particular weight is given to standard methods which can be applied to all species of interest. Two main aspects are more deeply analysed: the perfusion fixation and the effects of the osmolarity of the fixative vehicle. Using these standardized techniques, the embryonic endocardium of chick, mouse, dog, human and, to a lesser extent, rat hearts are described in SEM. All species investigated presented microvilli ruffles, filopodia, cytosegresomes, intercellular openings and phagocytes. Marginal folds, lamellipodia, dividing cells and incomplete endocardium could be observed in some species only. Each of these microappendages is discussed in relationship to observations of other authors on four levels - embryonic endocardium, adult endocardium, embryonic endothelium and adult endothelium. The general tendency in differentiation of the embryonic endocardium results in a progressive loss of the majority of the microappendages mentioned. Contrary to a relative absence of interspecific differences in endocardial morphology as seen in SEM, there is a strong variation of this morphology relating to the intracardiac localization of the endocardial cells. The discovery of autolytic postmortem changes in the material from pregnancies terminated by prostaglandins leads to the recommendation that the further use of this source of embryonic and fetal material be discouraged. Finally, the modifications of the morphology of embryonic endocardial cells under the effects of cytochalasin B, altered hemodynamics, and the hereditary congenital heart defects of the Keeshond strain of dogs are discussed, using the above-mentioned principles of four levels.
本综述在按照胚胎心内膜扫描电镜研究的时间顺序进行阐述之后，讨论了所研究的物种、阶段和定位。在回顾胚胎心内膜扫描电镜研究方法时，特别强调了可应用于所有相关物种的标准方法。对两个主要方面进行了更深入的分析：灌注固定以及固定剂载体渗透压的影响。运用这些标准化技术，在扫描电镜下描述了鸡、小鼠、狗、人类以及在较小程度上大鼠心脏的胚胎心内膜。所有研究的物种均呈现出微绒毛褶皱、丝状伪足、胞质分泌体、细胞间开口和吞噬细胞。仅在某些物种中可观察到边缘褶皱、片状伪足、分裂细胞和不完整的心内膜。在胚胎心内膜、成人心内膜、胚胎内皮和成人体内皮这四个层面上，结合其他作者的观察结果，对上述每种微附属器进行了讨论。胚胎心内膜分化的总体趋势是上述大多数微附属器逐渐消失。与扫描电镜下所见的心内膜形态种间差异相对缺乏相反，这种形态与心内膜细胞的心内定位密切相关。发现因前列腺素终止妊娠的材料存在自溶死后变化，因此建议不鼓励进一步使用这种胚胎和胎儿材料来源。最后，运用上述四个层面的原则，讨论了细胞松弛素B、血流动力学改变以及荷兰卷毛犬Keeshond品系遗传性先天性心脏缺陷对胚胎心内膜细胞形态的影响。
