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In modern pedagogical science, the study of the preparedness of future specialists for professional activity remains relevant. The research of many scientists has been devoted to the study of this problem in recent years. Revealing the essence of the state of preparedness of future primary school teachers for professional activity in physical culture, some authors consider it as a personal characteristic of a specialist, others as functional. Modern higher school pedagogy is faced with an important theoretical and practical task, which concerns improving the process of professional development of the personality of a teacher in general and a primary school teacher, in particular, to work on physical education. Ways and methods of forming preparedness for teacher activity among students of the pedagogical university are a complex socio-psychological phenomenon. It combines a complex of individual and psychological qualities of the personality, a certain system of professional and pedagogical knowledge, abilities, and skills. The teacher’s preparedness for work is considered a form of connection of a vocational and pedagogical orientation with the worldview, life attitudes, and spiritual values, as well as with the ethical, strong-willed, and emotional spheres. A significant drawback in this field of knowledge and practice continues to be the weak connection of theory with practice in the process of training in IHE. References to the experience of schools in the study of theory, the orientation to knowledge in the process of pedagogical practice don’t solve the problem yet, we are studying. We need special work of IHE, which would help to understand the theoretical and practical preparedness of students for pedagogical activity.

Oocytes cryopreservation is an important part of assisted reproduc tive technologies (ART) [12]. According to a new trend of delayed maternity, the oocytes and embryos are cryopreserved at early women reproductive age. Such an approach of fertility preservation permits to plan the most convenient life period for maternity, to accumulate oo cytes for women with low ovarian reserve, to treat infertility by ART with oocytes donation and to spare fertility in women undergoing gonadotoxic medical treatment [1,6,13]. In this regards, it is important to preserve not only morphological and functional characteristics of oocytes but either to keep intact their genetic apparatus. Oocytes’ meiotic spindle is very sensitive to the environmental changes and their microtubules gets depolymerize by slight temperature fluctuation [9, 15]. Meiotic apparatus disorders may cause an improper interaction between the oocyte chromosomes and as a result the number of aneu ploid embryos could be increased. Using a preimplantation genetic testing for aneuploidy (PGT-A) permits to select the embryos with a diploid chromosome number [14]. It has been reported that physical stress during oocyte vitrification affect the chromosome configuration and DNA integrity and suggested to determine the optimal condition, in particular, changing equilibration (up to 10 min) [8]. However, other authors reported that oocyte cryopreservation did not increase an aneuploidy in embryos, the implantation and live birth rates compared with the embryos derived from fresh oocytes cycles [7]. The aim of this work was to assess the impact of human oocytes cryopreservation on chromosomal status of preimplantation embryos.

The expedience of using oocytes with morphological dysmorphism in assisted reproduction tech- nology programs is debatable. This study aimed to estimate morphological and molecular cytogenetic char- acteristics of enlarged oocytes and to predict results of their further fertilization. Among 774 oocytes retrieved from 80 patients, 83 (11%) cells were enlarged. Morphometric analysis showed the diameter of the ooplasm to be (176.67 ± 1.76) μm and the diameter with ZP (200.8 ± 4.24) μm. Among these giant oocytes, 47 (56.6%) were at the metaphase II stage, 26 (31.3%) at the metaphase I stage, and 10 (12.1%) at the prophase I stage. The retrieved giant oocytes were characterized by dysmorphism of endo- and exocytoplasmic structures. Among 47 cells at the metaphase II stage, 40 (85.1%) oocytes had two polar bodies, three (6.4%) oocytes had one polar body, and four (8.5%) oocytes had a fragmented polar body. The assessment of the presence of mei- otic spindle by polarization microscopy showed that 39 (83%) oocytes had two meiotic spindles, 3 (6.4%) oocytes had one meiotic spindle, and 5 oocytes (10.6%) had no visualized meiotic spindles despite the pres- ence of polar bodies. After fertilization of 47 oocytes at the metaphase II stage, pronuclei were detected in 42 (89.4%) cells, including 9 (21.4%) oocytes with two pronuclei, 27 (63.3%) oocytes with 3 pronuclei, and 6 (15.3%) oocytes with four pronuclei. The molecular cytogenetic analysis demonstrated that the embryos obtained after fertilization of giant oocytes had a polyploid chromosome set number. Thus, the results of our study showed the inexpediency of using giant oocytes for further fertilization.

Development of novel prognostic criteria for evaluation in vitrofertilization of fresh and cryopreserved oocytes is an important component of modern assisted reproductive technologies. There was compared a degree of oolemma invagination during intracytoplasmic sperm injection into fresh and cryopreserved oocytes. The classification of the gamete turgor state based on oolemma degree invagination during intracytoplasmic sperm injection was developed. This behavior of oocyte membrane is a prognostic characteristic of zygotic formation rate. Oocytes with normal turgor were characterized by a high fertilization rate higher than 80%. Immediate oolemma puncture during oocyte micromanipulation showed structural and functional damage of membrane and led to further oocyte degeneration. After cryopreservation by a standard method the ratio of different types of oolemma invagination has been changed. A relative number of cells with normal turgor was decreased down to 54% due to an increase of oocyte number with higher membrane elasticity. The four-stage method of cryoprotective media removing after oocyte freeze-thawing is more effective for preserving gametes with normal turgor contrary to the standard two-stage one. Probl Cryobiol Cryomed 2018; 28(3): 258 – 265

Buriak, Iryna; Fleck, Roland A.; Goltsev, Anatoliy; Shevchenko, Nadiya; Petrushko, Maryna; Yurchuk, Taisiia; Puhovkin, Anton; Rozanova, Svitlana; Guibert, Edgardo Elvio; Robert, Maria Celeste; de Paz, Leonardo Juan; Powell-Palm, Matthew J.; Fuller, BarryTranslation of cryobiological techniques to socially economically deprived populations - Part 1: Cryogenic preservation strategies. ASME J Med Devices. 2020; 14(1): 010801 (1-14). Use of cold for preservation of biological materials, avoidance of food spoilage and to manage a variety of medical conditions has been known for centuries. The cryobiological science justified these applications in the 1960s increasing their use in expanding global activities. However, the engineering and technological aspects associated with cryobiology can be expensive and this raises questions about the abilities of resource-restricted low and middle income countries (LMICs) to benefit from the advances. This review was undertaken to understand where or how access to cryobiological advances currently exist and the constraints on their usage. The subject areas investigated were based on themes which commonly appear in the journal Cryobiology. This led in the final analysis for separating the review into two parts, with the first part dealing with cold applied for biopreservation of living cells and tissues in science, health care and agriculture, and the second part dealing with cold destruction of tissues in medicine. The limitations of the approaches used are recognized, but as a first attempt to address these topics surrounding access to cryobiology in LMICs, the review should pave the way for future more subject-specific assessments of the true global uptake of the benefits of cryobiology.

SummaryThe complexity of predicting embryo development potential at the cleavage stages and the emergence of epigenetic risks during prolonged in vitro culture of pre-implantation embryos made it more advantageous to transfer embryos at the morula stage to the uterine cavity. The criteria for estimating embryos at this stage that allow prediction of cryopreservation outcomes have been poorly described. All day 4 embryos (n = 224) were graded 1, 2, 3, 4 or 5 according to blastomere compaction degree (BCD = 100, 75, 50, 25 or 0%, respectively) and the survival and blastocyst formation rate of these morulae were studied after cryopreservation. An inverse dependence was found between survival rate and BCD. Excluded fragments were characterized by low osmotic reaction during exposure to cryoprotective medium and, after freeze-thawing, they were destroyed. As damaged necrotic areas of the embryo can affect their further development rate we proposed blastomeres and biopsy fragments of incomplete compacted morula be removed before embryo cryopreservation. This step led to significant increase in the post-thawing survival rate up to 93.1 ± 4.1%, 75 ± 8.8% and blastocyst formation rate up to 85.2 ± 10.4%, 59.4 ± 5.2% in grade 2 and grade 3 embryos, respectively. There was no significant difference in grade 4 embryos. Therefore the removal of blastomeres and biopsy fragments in incomplete compacted morulae can improve cryopreservation outcomes of grade 2 and grade 3 embryos with BCD.

Використання методів кріобіології в репродуктивній медицині дозволяє успішно кріоконсервувати гамети та ембріони пацієнтів, які проходять курс лікування безпліддя. У науковій літературі описано підходи щодо кріоконсервування як ооцитів, так й ембріонів, але порівняльний аналіз ефективності використання цих програм відсутній. У роботі вивчали основні ембріологічні та клінічні показники (частота запліднення та формування бластоцист; середня кількість ембріонів для перенесення до порожнини матки пацієнтки; частота настання вагітності; частота імплантації; кількість багатоплідних вагітностей) ооцитів або ембріонів після кріоконсервування. Досліджували ооцити на стадії метафази II мейозу та ембріони людини п'ятої доби розвитку (стадія бластоцисти). Показано, що кріоконсервування ооцитів методом вітрифікації не впливає на їх запліднюючу здатність, проте показник частоти формування бластоцист значуще нижчий, ніж у свіжовиділених ооцитів. Основні клінічні показники ефективності лікування співставні в групах із вітрифікацією ооцитів і ембріонів та в контролі. Доведено, що кріоконсервування ооцитів є альтернативою зберіганню ембріонів в умовах низьких температур.

This review describes the state of the art in cryopreservation of spermatozoa, oocytes and animal embryos. We have analyzed methodical approaches for the effective low-temperature preservation of the genetic resources of animal world and specified the procedures of cryopreservation of animal gametes and embryos. The history of efficient cryopreservation for animal reproductive cells and embryos was described. To date the germ cells and embryos of many laboratory, agricultural and wild animals have been successfully cryopreserved, nevertheless there is still pending the issue with the oocytes and embryos of some species of birds, fi shes and mammals. The paper discusses the ways for developing the methods to preserve the genetic material of those species that have not been successfully cryopreserved yet. Probl Cryobiol Cryomed 2019; 29(1): 003–018