Simpson R A, Mayhew T M, Barnes P R
Department of Human Morphology, Faculty of Medicine, Queen's Medical Centre, University of Nottingham, UK.
Placenta. 1992 Sep-Oct;13(5):501-12. doi: 10.1016/0143-4004(92)90055-x.
A method is presented for obtaining assumption-free estimates of the number of nuclei in the trophoblast of the human placenta and for defining the size of the trophoblast proliferative unit (TPU). The method relies on the disector, a stereological device for counting arbitrary particles in 3-dimensional space using pairs of parallel sections separated by a known distance. It is applied to investigate factors which contribute to trophoblast growth from 13 weeks of gestation to term. Physical disectors were sampled systematically using adjacent 4-4.6 microns thick paraffin sections. Nuclei in the trophoblast (syncytial and cellular) were counted if they appeared in an unbiased counting frame on one section but were absent from the adjacent section. Nuclear packing densities were converted to absolute numbers of nuclei by using placental volume as the reference space. At 37-39 weeks, the average placenta contained 6.4 x 10(10) trophoblast nuclei of which 90 per cent were located within the syncytium and the remainder in the cytotrophoblast. From a knowledge of total trophoblast volume, it was found that each nucleus is associated with 970 microns3 of trophoblast and each cytotrophoblast cell with 11,000 microns3. The latter may be regarded as the volume of a TPU. From 13 weeks of gestation to term, there was a ninefold increase in nuclear number but the trophoblast volumes associated with nuclei, including the size of the TPU, remained constant. Growth of trophoblast is purely hyperplastic and occurs by recruitment of new TPUs.
本文介绍了一种方法，用于获得人胎盘滋养层细胞核数量的无假设估计值，并确定滋养层增殖单位（TPU）的大小。该方法依赖于解剖器，这是一种体视学装置，用于通过一对由已知距离分隔的平行切片在三维空间中计数任意颗粒。该方法用于研究从妊娠13周到足月时滋养层生长的影响因素。使用相邻的4-4.6微米厚的石蜡切片系统地采集物理解剖器样本。如果滋养层（合体滋养层和细胞滋养层）中的细胞核出现在一个切片的无偏计数框中，但在相邻切片中不存在，则对其进行计数。通过将胎盘体积作为参考空间，将核堆积密度转换为绝对核数。在37-39周时，平均胎盘含有6.4×10¹⁰个滋养层细胞核，其中90%位于合体滋养层内，其余位于细胞滋养层中。根据总滋养层体积的知识，发现每个细胞核与970立方微米的滋养层相关联，每个细胞滋养层细胞与11,000立方微米相关联。后者可被视为一个TPU的体积。从妊娠13周到足月，核数量增加了九倍，但与细胞核相关的滋养层体积，包括TPU的大小，保持不变。滋养层的生长纯粹是增生性的，通过招募新的TPU发生。
