Nuclear vlimata and aneuploidy in embryonic cells is caused by meiosis. Behaviour and properties of meiotic cells.

This study demonstrates that human embryonic cells divide by meiosis. The use of trophoblastic tissue cells (early embryo) and amniotic cells (late embryo) exhibited the following characteristic events of meiosis: nuclear (NVs) and nucleolar (NuVs) vlimata formation; NV invasion in host cells; extrusion of chromosomes; nuclear fusion; metaphase fusion; hybrid cell formation; nuclear, nucleolar and cytoplasmic bridges, chromosomal transfer, variable-sized nuclei; nuclear fragmentation; condensed meiotic chromosomes; "O" chromosome; and aneuploidy. Two types of nuclear bridges (NBs) were identified and defined as communicative tubules through which chromosomal transfer among cells is achieved. The wall of NBs is an extension of the nuclear membrane and the lumen contained chromosomal fusion substance (CFS). Embryonic cells formed glycosaminoglycan-sacs (GSG-sacs) and rivulets, forming a cytoplasmic communicative system. The extracellular matrix (ECM), GSG-sacs and CFS were composed of glycosaminoglycan-bound protease. The protease which immuno-crossreacted with the a1-chymotrypsin antiserum was the meiotic calcium-activated activated neutral proteinase (CANP). Cytogenetic analysis of early embryonic cells showed higher ratio of aneuploidy:diploidy than late embryonic cells. The results are discussed in terms of differentiation-mitosis and undifferentiation-meiosis. These observations lead to an embryonic cell life cycle identical to that of malignant cells as follows: [formula: see text].