Tykholaz V. Patterns of development of the structures of the human medulla oblongata in the prenatal period of ontogenesis and in case of malformations.

A study of the medulla oblongata of 230 embryos and human fetuses from 6 to 40 weeks, as well as 10 fetuses with the malformations (siamese twins, tower skull, sacrococcygeal teratoma, spina bifida, anencephaly) was carried out with the help of anthropometric, general histological, neurohistological and immunohistological methods. A comparison of the obtained results with the similar results in human fetuses without developmental malformations was performed. In the course of the study, the size of the basal and alar plates in different sections of the hindbrain was determined, and the ratio of the layers of the neural tube within the hindbrain was found. The macrometric parameters of the medulla oblongata and olives in the human fetus and periods of their intensive growth were established. The morphology of the ependymal layer within the medulla oblongata was determined and changes in the morphometric parameters of the given layer in the process of prenatal ontogenesis were revealed. The age characteristics of radial glia fibers during the fetal development of the embryo and fetus were established. The asynchronous nature of growth and differentiation of nuclei of the medulla oblongata and nerve cells of these nuclei in the process of prenatal ontogenesis were revealed. The macrostructure of the nuclei of the medulla oblongata was investigated, the terms of establishment of the final structure and form of the medulla oblongata nuclei by nerve cells were determined, the morphometric parameters of the nerve cells and their nuclei as well as the periods of their intensive growth were determined. With the help of immunohistochemical markers, changes in the proliferative and antiapoptotic activity of cells of the ependymal layer were determined and the patterns of expression of the S100 and synaptophysin proteins in neuroblasts of the neural complexes of the medulla oblongata were revealed.