[Mitomycin C Treatment of Stromal Layers Enhances the Support of In Vitro Hematopoiesis in Co-Culture Systems].

A study was made of the effect that mitomycin C (MitC) treatment of stromal layers of NIH 3T3 cells expressing Jagged1, a ligand of the Notch receptor, exerts on the growth of hematopoietic Lin(-) mouse bone marrow cells in a co-culture system. MitC treatment of stromal cells significantly increased the number of hematopoietic cells and the frequency of colony-forming cells in stromal co-cultures. Transcriptome analysis of control and MitC-treated stromal cell samples was performed by differential RNA sequencing, and genes downregulated by MitC treatment were predominantly associated with the control of cell proliferation, the cell cycle, chromosome segregation, and DNA metabolism. Induction of key hematopoietic cytokines by MitC was not detected by the transcriptome analysis and was therefore not a main factor in the activation of hematopoiesis on the treated stroma. At the same time, the set of the genes most strongly upregulated by MitC treatment is enriched in the genes for cytokines, growth factors, and cell surface proteins, which presumably contribute to enhanced hematopoiesis support on the MitC-treated stroma. Products of some of these genes have been implicated in expansion of hematopoietic stem/progenitor cells in vitro or in vivo.

[Aneuploidy frequency in sperm of fertile men].

Analysis of sperm aneupoidy in 11 healthy men using two- or three-color FISH permitted to determine the average frequency of disomy in chromosomes 13 and 21 (0.11% and 0.2%, respectively), disomy in chromosome 18 (0.05%) and reveal gonosomal aneuploidy variants and their frequency. The frequency of XX disomy was 0.04%; XY, 0.17%; YY, 0.06%; and gonosomal nullisomy, 0.29%. We also assessed the frequency of meiotic nondisjunction of chromosomes 13, 21, 18, X, and Y and the frequency of XX, XY, and YY diploid chromosomes in sperm. The XY variant prevailed in gonosomal aneuploidy and diploidy and was associated with abnormal chromosomal segregation in meiotic anaphase I. The contribution of human sperm chromosomal imbalance to early embryonic lethality and to some chromosomal diseases of syndrome type in the offspring is discussed.