Abnormal methylation of PRDM16 and PTPRN2 genes in chorionic villi in miscarriage

Relevance. Abnormal epigenetic regulation of genes responsible for the development of the embryo and placenta is associated with many pregnancy pathologies. Aim. The aim of this work was to analyze the prevalence of abnormal methylation of the PRDM16 and PTPRN2 genes in chorionic villi of spontaneous abortions with normal karyotype and with the most frequent aneuploidies (trisomy 16 and monosomy X). Materials and Methods. The methylation profile was evaluated using targeted bisulfite massive parallel sequencing in chorionic villi of induced abortions (n = 10), spontaneous abortions with normal karyotype (n = 39), trisomy 16 (n = 17) and monosomy X (n = 20) and peripheral blood lymphocytes of healthy volunteers (n = 6). Results and Discussion. In analyzed genes, differential methylation of individual CpG sites was found in chorionic villi of spontaneous abortions. Despite the absence of significant differences between the groups in the average level of methylation in analyzed gene regions, abnormal methylation of the PRDM16 and PTPRN2 genes were detected for 33 % and 5 % of spontaneous abortions, respectively, indicating a high incidence of epigenetic abnormalities in these genes in the chorionic villi of spontaneous abortions. The level of methylation of the PRDM16 gene significantly correlated with the level of methylation of the retrotransposon LINE-1, which indicates the generalized nature of methylation disorders in spontaneous abortions. Finally, the level of methylation of the PTPRN2 gene depended on the age of mothers of spontaneous abortions with monosomy X, which raises the question of the influence of maternal factors on the methylation profile in this group of spontaneous abortions. Conclusion. The results indicate that epigenetic disorders of the PRDM16 gene may be associated with spontaneous termination of pregnancy in the first trimester

LINE-1 retrotransposon methylation in chorionic villi of first trimester miscarriages with aneuploidy

Purpose High frequency of aneuploidy in meiosis and cleavage stage coincides with waves of epigenetic genome reprogramming that may indicate a possible association between epigenetic mechanisms and aneuploidy occurrence. This study aimed to assess the methylation level of the long interspersed repeat element 1 (LINE-1) retrotransposon in chorionic villi of first trimester miscarriages with a normal karyotype and aneuploidy. Methods The methylation level was assessed at 19 LINE-1 promoter CpG sites in chorionic villi of 141 miscarriages with trisomy of chromosomes 2, 6, 8-10, 13-15, 16, 18, 20-22, and monosomy X using massive parallel sequencing. Results The LINE-1 methylation level was elevated statistically significant in chorionic villi of miscarriages with both trisomy (45.2 +/- 4.3%) and monosomy X (46.9 +/- 4.2%) compared with that in induced abortions (40.0 +/- 2.4%) (p < 0.00001). The LINE-1 methylation levels were specific for miscarriages with different aneuploidies and significantly increased in miscarriages with trisomies 8, 14, and 18 and monosomy X (p < 0.05). The LINE-1 methylation level increased with gestational age both for group of miscarriages regardless of karyotype (R = 0.21, p = 0.012) and specifically for miscarriages with trisomy 16 (R = 0.48, p = 0.007). LINE-1 methylation decreased with maternal age in miscarriages with a normal karyotype (R = - 0.31, p = 0.029) and with trisomy 21 (R = - 0.64, p = 0.024) and increased with paternal age for miscarriages with trisomy 16 (R = 0.38, p = 0.048) and monosomy X (R = 0.73, p = 0.003). Conclusion Our results indicate that the pathogenic effects of aneuploidy in human embryogenesis can be supplemented with significant epigenetic changes in the repetitive sequences

Improving the Method of Rotational Broaching in the Production of Profile Openings on the Lathes of Turning Group

We examined methods of manufacturing profile openings on the metal-cutting machines by the rotational broaching method. Based on the generalized results of analysis of the methods for manufacturing profile openings, we proposed a method of rotational broaching. Bits for drilling machines or screwdrivers are used as the tool. Hardness of the bit is quite high; therefore, making a centering opening in it is difficult. The problem is solved by pressing a transition bushing onto the bit, with a centering opening made in advance. Implementation of the method requires a Morse cone with a welded plate. This allows fixing the rotating centre in a tool carrier. The proposed method makes it possible at minimal financial cost to perform the shaping of profile openings within a wide range of both the shape and nominal dimensions. The method is based on the effect of self-centering and, therefore, does not require preliminary adjustment. Adjusting tool entrance angle is achieved by displacing a transverse support of the lathe and by tool carrier rotation. In addition, in the production of profile opening, its input cone is formed, which provides for easy installation of the wrench to transmit rotational moment without losing load capacity. The studies conducted defined suboptimal values of the input variables that are accepted as rational in the examined technological process of rotational broaching. These are: a tool entrance angle (1.5...2.5 degrees), its supply (0.1...0.3 mm/rev) and the rate of processing (15...25 m/min

Aneuploidy and DNA Methylation as Mirrored Features of Early Human Embryo Development

Genome stability is an integral feature of all living organisms. Aneuploidy is the most common cause of fetal death in humans. The timing of bursts in increased aneuploidy frequency coincides with the waves of global epigenetic reprogramming in mammals. During gametogenesis and early embryogenesis, parental genomes undergo two waves of DNA methylation reprogramming. Failure of these processes can critically affect genome stability, including chromosome segregation during cell division. Abnormal methylation due to errors in the reprogramming process can potentially lead to aneuploidy. On the other hand, the presence of an entire additional chromosome, or chromosome loss, can affect the global genome methylation level. The associations of these two phenomena are well studied in the context of carcinogenesis, but here, we consider the relationship of DNA methylation and aneuploidy in early human and mammalian ontogenesis. In this review, we link these two phenomena and highlight the critical ontogenesis periods and genome regions that play a significant role in human reproduction and in the formation of pathological phenotypes in newborns with chromosomal aneuploidy

Improving the Abrasive Resistance of a Slide Frame in a Mortar Mixer

A method has been proposed for machining the outer and inner conical surfaces of the wrist pin and insert, which represent a sliding friction pair on the mortar mixer frame. The machining implies the application on the conical surface of parts, preliminary prepared through turning, of a wear-resistant material in the form of a hard alloyed nickel-based powder. It is applied with a special burner with a hopper-dispenser filled with powder. The result of mixing a combustible gas (acetylene and oxygen) in the burner with the powder from the hopper is melting.In the course of implementing a given technological process, by using mathematical modeling methods, we have determined the optimal mode parameters (PG10N-01 powder consumption is 33.5 g/min.; oxygen flow rate is 7.0 l/min; acetylene pressure is 0.043 MPa) for the gas-flame surfacing, which ensured maximum effect, that is, the greatest strength of adhesion (45 MPa) for the surfaced coating. The surfaced coating quality was checked by using a pin method for determining the adhesion strength between the new coating and the base on a tensile testing machine.A series of experimental studies into the enhancement of abrasive resistance of a sliding frame, namely a comparison of the surfaced coating with other well-known wear-resistant materials such as steel ShKh15, KhVG, were carried out at a specially designed experimental bench. Its structure is based on a vertically drilling desktop machine adjusted to the conditions of a working process that occurs inside the body of a mortar mixer. These include an abrasive medium, and the radial and axial efforts. To determine the axial load on a frame, we have proposed a structure of the hydraulic device, which includes a pressure gauge, a piston, a sleeve, and a ball. The axial load has been found for the most unfavorable conditions of mixer operation. Its value was implemented at an experimental wear bench. In addition, we have performed a series of experimental studies to determine an optimum angle of the cone at the apex of the wrist pin and insert in a conical slide frame for the minimal wear.Using the proposed technique of a gas-flame surfacing could significantly improve the abrasive and corrosion resistance of a slide frame, thereby prolonging the lifespan of a mortar mixer in general, as well as the overhaul cycle for equipment designed to prepare soluble mixtures used for constructio

ПроектуваннЯ кривОшипнО-шатуннОгО механізмУ пОршневОгО насосУ

Наведені розрахунки оптимального зміщення вісі валу кривошипу відносно осі поршня насосу, що застосовується для перекачування трубопроводами різноманітних рідин у нафтовій, газовій та нафтохімічній галузях промисловості

Modernization of the Technique for Rotary Shape-formation of Outer Profiled Surfaces

We have proposed a technique for obtaining outer profiled surfaces, which is characterized by affordability and low cost of equipment used. The technique is based on that a regular rotating center is fixed in a lathe's tool holder in a special way. A basic socket head of the required profile is applied as a profile-forming matrix. A tool holder's rotation angle ensures a fracture angle of the rotating center's axis relative to the axis of a workpiece rotation. A value for the fracture angle reaches 1.5°. The end surface edge of the matrix executes a reciprocating motion per every rotation of the lathe chuck along the surface of a workpiece. In this case, the end surface of the matrix and a workpiece are in contact at a single point, going deeper by the magnitude of feed per every rotation of the chuck.Application of a given technique is an alternative to existing technique of rotational shape-formation of outer profiled surfaces, whose implementation requires specialized equipment and specialized cutting tools, the price for which is quite high (UAH 57,000 and UAH 6,000, respectively). In addition, changing the size or shape of the required profile necessitates installing a new cutting tool, replacing which requires additional adjustment.The tests were carried out when manufacturing the twelve-point outer surface the size of S10. An analysis of vibrograms from the shape-formation process has established the most rational variant of equipment for manufacturing profiled outer surfaces. We have manufactured pilot outer profiled surfaces, such as hexagon the size of S10, the TORX surface the size of E14, and others. They confirmed a possibility for successful manufacturing of different profiled outer surfaces using the proposed tooling.Using the proposed technique, which implies low cost and does not require specialized equipment, could significantly expand the scope of application of conjugated surfaces with a profiled shape in mechanical engineerin