Cytogenetic behavior of cryoprotectant DMSO

IVF (in vitro fertilization) is now used worldwide to overcome female or male infertility. Cryopreservation of human embryos provides the clearest opportunity to improve the clinical results obtained with IVF. Cryoprotective agents (CPA) are used to minimize freezing injuries. DMSO has been the most widely used CPA, however, high concentrations of CPAs in the vitrification solution have been shown to be detrimental to the cell. In order to determine the effect of DMSO solutions (5%, 10% and 20%) on genetic stability and/or subsequent DNA repair, we have investigated its ability to induce Sister Chromatid Exchanges (SCEs) and Proliferation Rate Index (PRI) in normal human lymphocyte cultures of peripheral blood, due to the fact that the study cannot be conducted on embryos and to the limited number of spare available embryos, the corresponding accessible experimental material was T lymphocyte. The blood samples were taken from three different healthy donors (conducting experimental procedure in triplicate). After the effect of DMSO solutions on blood according to the instructions of kit K-SIBV-500, lymphocytes are harvested and cultured with suitable technique to assess SCEs and PRI. The results show that all three DMSO concentrations cause a statistically dose depended significant increase of SCE frequency of the lymphocytes (p<0.001) and raise the need for more research regarding the safe and effective use of cryoprotectant

The impact of sars-cov-2 on sperm cryostorage, theoretical or real risk?

Cryopreservation of human gametes and embryos as well as human reproductive tissues has been characterized as an essential process and aspect of assisted reproductive technology (ART). Notably, sperm cryopreservation is a fundamental aspect of cryopreservation in oncological patients or patients undergoing gonadotoxic treatment. Given that there is a risk of contamination or cross-contamination, either theoretical or real, during the procedures of cryopreservation and cryostorage, both the European Society for Human Reproduction and Embryology (ESHRE) and the American Society for Reproductive Medicine (ASRM) have provided updated guidelines for preventing or reducing the contamination risk of sexually transmitted viruses. Given the ongoing and worldwide COVID-19 pandemic, there is considerable interest in what measures should be taken to mitigate SARS-CoV-2 contamination during cryopreservation and cryostorage of semen samples. The SARS-CoV-2 virus is the virus that causes COVID-19, and whose transmission and infection is mainly aerosol-mediated. Several ART professional societies, including ESHRE and ASRM have proposed measures to mitigate the spread of the SARS-CoV-2 virus. Whether the proposed safety directives are enough to mitigate the possible SARS-CoV-2-contamination of sperm samples during cryopreservation or whether the policies should be re-evaluated will be discussed in this review. Additionally, insights regarding the possible impact of COVID-19 vaccination on the safety of sperm cryopreservation will be discussed

Influence of conception and delivery mode on stress response marker Oct4B1 and imprinted gene expression related to embryo development: A cohort study

Background: Recent scientific data support that the mode of conception and delivery may influence epigenetic regulation and therefore embryo development. Octamer-binding transcription factor 4-B1 (OCT4B1), a novel variant of OCT4 with yet unknown biological function, is suggested to have a potential role in mediating cellular stress response. Furthermore, Insulinlike Growth Factor 2 (IGF2), Mesoderm-specific Transcript (MEST) and paternally expressed gene 10 (PEG10) are genes known as imprinted and are regulated via means of epigenetic regulation. The influence of delivery mode and conception on epigenetic regulation is an active research field. Objective: Our aim was to correlate the expression level of Oct4B1 and the expression and methylation level of IGF2, MEST, and PEG10 imprinted genes with the mode of delivery and conception in the umbilical cord blood of newborns. Materials and Methods: Samples of umbilical cord blood from infants born after vaginal delivery, caesarean section (CS) with the infant in cephalic position and CS due to breech position were examined. Furthermore, the investigation included infants conceived through means of assisted reproductive technology. Results: No statistically significant differences were found in mRNA expression levels between different modes of conception and delivery (p = 0.96). Oct4B1, IGF2, MEST, and PEG10 expression levels do not seem to be significantly affected by different modes of conception and delivery. Conclusion: These results indicate that the expression and methylation patterns of Oct4B1, IGF2, MEST and PEG10 in umbilical cord blood are not affected by the conception and delivery mode. Key words: Conception, Fertilization in vitro, Genomic imprinting, Fetal blood

Requirements for NuMA in maintenance and establishment of mammalian spindle poles

Microtubules of the mitotic spindle in mammalian somatic cells are focused at spindle poles, a process thought to include direct capture by astral microtubules of kinetochores and/or noncentrosomally nucleated microtubule bundles. By construction and analysis of a conditional loss of mitotic function allele of the nuclear mitotic apparatus (NuMA) protein in mice and cultured primary cells, we demonstrate that NuMA is an essential mitotic component with distinct contributions to the establishment and maintenance of focused spindle poles. When mitotic NuMA function is disrupted, centrosomes provide initial focusing activity, but continued centrosome attachment to spindle fibers under tension is defective, and the maintenance of focused kinetochore fibers at spindle poles throughout mitosis is prevented. Without centrosomes and NuMA, initial establishment of spindle microtubule focusing completely fails. Thus, NuMA is a defining feature of the mammalian spindle pole and functions as an essential tether linking bulk microtubules of the spindle to centrosomes

Aneuploidy in pluripotent stem cells and implications for cancerous transformation

Owing to a unique set of attributes, human pluripotent stem cells (hPSCs) have emerged as a promising cell source for regenerative medicine, disease modeling and drug discovery. Assurance of genetic stability over long term maintenance of hPSCs is pivotal in this endeavor, but hPSCs can adapt to life in culture by acquiring non-random genetic changes that render them more robust and easier to grow. In separate studies between 12.5% and 34% of hPSC lines were found to acquire chromosome abnormalities over time, with the incidence increasing with passage number. The predominant genetic changes found in hPSC lines involve changes in chromosome number and structure (particularly of chromosomes 1, 12, 17 and 20), reminiscent of the changes observed in cancer cells. In this review, we summarize current knowledge on the causes and consequences of aneuploidy in hPSCs and highlight the potential links with genetic changes observed in human cancers and early embryos. We point to the need for comprehensive characterization of mechanisms underpinning both the acquisition of chromosomal abnormalities and selection pressures, which allow mutations to persist in hPSC cultures. Elucidation of these mechanisms will help to design culture conditions that minimize the appearance of aneuploid hPSCs. Moreover, aneuploidy in hPSCs may provide a unique platform to analyse the driving forces behind the genome evolution that may eventually lead to cancerous transformation

Chromosomal aneuploidy in the human pre- and post- implantation conceptus

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Is the sperm centrosome to blame for the complex polyploid chromosome patterns observed in cleavage stage embryos from an OAT patient?

Oligoasthenoteratozoospermia (OAT) is defined by a combined low count < 20 x 10(6) sperm/ml, poor motility < 50 % forward progression or < 25 % rapid linear progression and abnormal morphology (5-8% normal using Kruger strict criteria) and has been associated with increased levels of sperm aneuploidy. Here we report on the cytogenetic findings from three 'spare' embryos from a couple that were referred for ICSI because of OAT. The embryos were processed for sequential FISH in three hybridization rounds using probes for chromosomes 3, 7, 9, 13, 17, 18, 21, X and Y. Molecular cytogenetic analysis of nine chromosomes revealed that all three embryos were female polyploid. One of them was uniformly tetraploid for all chromosomes tested, while the remaining two embryos showed evidence of abnormal postzygotic segregation of chromosomes, causing the derivative blastomeres to have uneven chromosomal constitution. In one of them in particular, the non-disjoining chromosomes showed preferential segregation to the same pole, rather than randomly moving towards either pole, suggesting an abnormal spindle and causing the derivative blastomeres to have significantly uneven chromosomal constitutions. The possible scenarios leading to polyploidy and chromosomal imbalance through cytokinetic failure and subsequent abnormal centrosomal distribution are outlined

Εντοπισμός βλαβών φωτοβολταϊκών στοιχείων με θερμογραφική ανάλυση

Διπλωματική εργασία που υποβλήθηκε στη σχολή ΗΜΜΥ του Πολυτεχνείου Κρήτης για την πλήρωση προϋποθέσεων λήψης πτυχίου.Περίληψη: Η ηλιακή ενέργεια είναι μια ελκυστική εναλλακτική πηγή ηλεκτρισμού. Το φωτοβολταϊκό στοιχείο, είναι η βασική μονάδα μιας εγκατάστασης παραγωγής ηλεκτρικής ενέργειας από την ηλιακή ενέργεια. Για την συντήρηση ενός τέτοιου συστήματος είναι αναγκαία η άμεση διάγνωση τυχόν βλαβών στα φωτοβολταϊκά στοιχεία της εγκατάστασης. Ο πιο απλός, γρήγορος και μη καταστρεπτικός τρόπος είναι με χρήση τεχνικών θερμογραφικής ανάλυσης. Οι τεχνικές θερμογραφικής ανάλυσης μπορούν να χρησιμοποιηθούν για την γρήγορη διάγνωση βλαβών, όχι μόνο κατά την λειτουργία των Φ/Β πλαισίων αλλά και κατά την φάση κατασκευής τους. Σε αυτή την διπλωματική εργασία αρχικά μελετήθηκαν διάφορες τεχνικές που χρησιμοποιούνται για τον εντοπισμό σφαλμάτων κατά την διαδικασία κατασκευής φωτοβολταϊκών πλαισίων. Στη συνέχεια, αναπτύχθηκε ένα λογισμικό ηλεκτρονικού υπολογιστή το οποίο δέχεται ως είσοδο την θερμική φωτογραφία ενός φωτοβολταϊκού πλαισίου ή μίας φωτοβολταϊκής συστοιχίας, τα οποία είναι εγκατεστημένα σε ένα σύστημα παραγωγής ηλεκτρικής ενέργειας, και εντοπίζει τυχόν βλάβες σε αυτά.Summarization: Solar energy is an attractive alternative source of electricity. The solar cell is the basic unit of a solar power plant. The maintenance of such a system requires the immediate discovery of malfunctions of the solar cells/modules it comprises. The most simple, fast and non-destructive way of diagnosing faults on photovoltaic modules are techniques of thermographic analysis. The thermographic analysis techniques can be used for quick fault diagnosis, not only during the operation of photovoltaic module but also during the construction phase. In this thesis, various techniques used to detect faults during the manufacturing process of photovoltaic modules are initially studied. Then, a computer software is developed that accepts as input a thermal image of a photovoltaic module or array, which is installed in a power system, and identifies the corresponding malfunctioning solar cells, as well as the types of faults

The effects of postnatal exposure of endocrine disruptors on testicular function: a systematic review and a meta-analysis

Background: Despite many epidemiological studies having been conducted, the impact of postnatal exposure of endocrine disruptors (EDs) on testicular function remains a controversial issue. Aim: To systematically review the literature and perform a quantitative synthesis to evaluate the effect of EDs on testicular function. Materials and methods: A comprehensive search was conducted in the MEDLINE, Scopus, and CENTRAL databases. Eligible for the systematic review were observational (cross-sectional and cohort) studies with (i) adult men who had a high probability of postnatal exposure to EDs (“exposed”), (ii) adult men who had a low probability of postnatal exposure to EDs (“non-exposed”), and (iii) an outcome of interest [seminal parameters and reproductive hormone concentrations]. The continuous outcomes in each of the studies were synthesized by the random effects model and expressed as standardized mean difference (SMD) with 95% confidence interval (CI). Results: Thirteen studies, including 959 exposed and 907 non-exposed men, fulfilled the inclusion criteria. Exposure to EDs was associated with decreased LH [SMD − 0.17, 95% CI − 0.33 to − 0.02, 10 studies (616 exposed, 563 non-exposed), I2 40%, p = 0.09], progressive motility [SMD − 0.45, 95% CI − 0.77 to − 0.13, three studies (133 cases, 153 controls), I2 38%, p = 0.20], and normal morphology [SMD − 0.50, 95% CI − 0.85 to − 0.14, eight studies (562 cases, 540 controls), I2 87%, p &amp;lt; 0.01] compared with non-exposure. No difference was observed between the other study groups. Conclusions: Postnatal exposure to EDs is associated with decreased semen quality. Nevertheless, there is no evidence that a disruption of testicular function mediates the deterioration in semen quality. © 2020, Hellenic Endocrine Society