Relevant bibliographies by topics / Oocyte

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Oocyte'

Author: Grafiati
Published: 4 June 2021
Last updated: 7 July 2024

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Journal articles on the topic "Oocyte"

1

Budna, Joanna, Artur Bryja, Piotr Celichowski, Rotem Kahan, Wiesława Kranc, Sylwia Ciesiółka, Marta Rybska, et al. "Genes of cellular components of morphogenesis in porcine oocytes before and after IVM." Reproduction 154, no. 4 (October 2017): 535–45. http://dx.doi.org/10.1530/rep-17-0367.

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Proper oocyte maturation in mammals produces an oocyte capable of monospermic fertilization and embryo preimplantation. The cumulus-oocyte complexes (COCs), surrounding an oocyte, play a significant role in oocyte maturation. During this process, when the COCs undergo cumulus expansion wherein tightly compact cumulus cells (CCs) form a dispersed structure, permanent biochemical and molecular modifications occur in the maturing oocytes, indicating that the gene expression between immature and mature oocytes differs significantly. This study focuses on the genes responsible for the cellular components of morphogenesis within the developing oocyte. Brilliant cresyl blue (BCB) was used to determine the developmental capability of porcine oocytes. The immature oocytes (GV stage) were compared with matured oocytes (MII stage), using microarray and qRT-PCR analysis to track changes in the genetic expression profile of transcriptome genes. The data showed substantial upregulation of genes influencing oocyte’s morphology, cellular migration and adhesion, intracellular communication, as well as plasticity of nervous system. Conversely, downregulation involved genes related to microtubule reorganization, regulation of adhesion, proliferation, migration and cell differentiation processes in oocytes. This suggests that most genes recruited in morphogenesis in porcine oocytein vitro,may have cellular maturational capability, since they have a higher level of expression before the oocyte’s matured form. It shows the process of oocyte maturation and developmental capacity is orchestrated by significant cellular modifications during morphogenesis.
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Pedersen, Hanne Skovsgaard, Peter Løvendahl, Knud Larsen, Lone Bruhn Madsen, and Henrik Callesen. "Porcine oocyte mtDNA copy number is high or low depending on the donor." Zygote 24, no. 4 (December 18, 2015): 617–23. http://dx.doi.org/10.1017/s0967199415000611.

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SummaryOocyte capacity is relevant in understanding decreasing female fertility and in the use of assisted reproductive technologies in human and farm animals. Mitochondria are important to the development of a functionally good oocyte and the oocyte mtDNA copy number has been introduced as a useful parameter for prediction of oocyte competence. The aim of this study was to investigate: (i) if the oocyte donor has an influence on its oocyte's mtDNA copy number; and (ii) the relation between oocyte size and mtDNA copy number using pre- and postpubertal pig oocytes. Cumulus–oocyte complexes were collected from individual donor pigs. The oocytes were allocated into different size-groups, snap-frozen and single-oocyte mtDNA copy number was estimated by quantitative real-time PCR using the genes ND1 and COX1. Results showed that mean mtDNA copy number in oocytes from any individual donor could be categorized as either ‘high’ (≥100,000) or ‘low’ (<100,000) with no difference in threshold between pre- and postpubertal oocytes. No linear correlation was detected between oocyte size and mtDNA copy number within pre- and postpubertal oocytes. This study demonstrates the importance of the oocyte donor in relation to oocyte mtDNA copy number, irrespectively of the donor's puberty status and the oocyte's growth stage. Observations from this study facilitate both further investigations of the importance of mtDNA copy number and the unravelling of relations between different mitochondrial parameters and oocyte competence.
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Walker, Bailey N., and Fernando H. Biase. "The blueprint of RNA storages relative to oocyte developmental competence in cattle (Bos taurus)." Biology of Reproduction 102, no. 4 (January 26, 2020): 784–94. http://dx.doi.org/10.1093/biolre/ioaa015.

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Abstract From the time oocytes leave quiescence, there are constant microenvironmental influences contributing to development, thus acquiring developmental competence is not a simple, linear phenomenon. During folliculogenesis, oocytes experience many morphological and cytological changes that contribute toward the acquisition of developmental competence, a process defined by an oocyte’s ability to progress through folliculogenesis, be fertilized, undergo cleavage, and develop into an embryo. Many factors, such as ovarian follicle size, cow age, and the morphology of the cumulus–oocyte complex, have been extensively investigated to understand this process. In parallel to aiding in the understanding of oocyte biology, these features have been used to characterize an oocyte’s ability to achieve competence. In addition, oocytes undergo intense gene transcription and protein translation to accumulate the maternal stores. When the oocyte is fully grown, most genes are transcriptionally inactive, and the chromatin is densely compacted. More recently, RNA profiling has been used to further define the transcriptional parameters that are associated with oocyte development. Here, focusing on cattle, we provide an overview of the experimental models commonly used to understand the underlying biology related to oocyte developmental competence. We compiled public data and showed that cattle oocytes can express over 15 000 protein-coding genes, suggesting a complex transcriptome landscape. Surprisingly, less than 2% of the expressed genes have been linked to developmental competence. The identification of the gene products that contribute to oocyte development, and understanding their biological function, are a vital component of our quest toward defining oocyte developmental competence at the molecular level.
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4

Ritter, Lesley J., Satoshi Sugimura, and Robert B. Gilchrist. "Oocyte Induction of EGF Responsiveness in Somatic Cells Is Associated With the Acquisition of Porcine Oocyte Developmental Competence." Endocrinology 156, no. 6 (June 1, 2015): 2299–312. http://dx.doi.org/10.1210/en.2014-1884.

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Abstract Oocytes progressively acquire the competence to support embryo development as oogenesis proceeds with ovarian folliculogenesis. The objectives of this study were to investigate oocyte-secreted factor (OSF) participation in the development of somatic cell epidermal growth factor (EGF) responsiveness associated with oocyte developmental competence. A well-established porcine model was employed using oocytes from small (&lt;4 mm) vs medium sized (&gt;4 mm) antral follicles, representing low vs moderate developmental competence, respectively. Cumulus-oocyte complexes (COCs) were treated in vitro with inducers of oocyte maturation, and cumulus cell functions and oocyte developmental competence were assessed. COCs from small follicles responded to FSH but, unlike COCs from larger follicles, were incapable of responding to EGF family growth factors known to mediate oocyte maturation in vivo, exhibiting perturbed cumulus expansion and expression of associated transcripts (HAS2 and TNFAIP6). Low and moderate competence COCs expressed equivalent levels of EGF receptor (EGFR) mRNA; however, the former had less total EGFR protein leading to failed activation of phospho-EGFR and phospho-ERK1/2, despite equivalent total ERK1/2 protein levels. Native OSFs from moderate, but not from low, competence oocytes established EGF responsiveness in low competence COCs. Four candidate recombinant OSFs failed to mimic the actions of native OSFs in regulating cumulus expansion. Treatment with OSFs and EGF enhanced oocyte competence but only of the low competence COCs. These data suggest that developmental acquisition by the oocyte of capacity to regulate EGF responsiveness in the oocyte's somatic cells is a major milestone in the oocyte's developmental program and contributes to coordinated oocyte and somatic cell development.
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Virant-Klun, Irma, Katja Knez, Tomaz Tomazevic, and Thomas Skutella. "Gene Expression Profiling of Human Oocytes Developed and MaturedIn VivoorIn Vitro." BioMed Research International 2013 (2013): 1–20. http://dx.doi.org/10.1155/2013/879489.

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The quality of the human oocyte determines the success of fertilization and affects the consequent embryo development, pregnancy and birth; it therefore serves as a basis for human reproduction and fertility. The possibility to evaluate oocyte quality in thein vitrofertilization programme is very limited. The only criterion which is commonly used to evaluate oocyte quality is its morphology. There is a mass of oocytes in thein vitrofertilization programme which are not fertilized in spite of normal morphology. In the past, several attempts focused on oocyte gene expression profiling by different approaches. The results elucidated groups of genes related to the human oocyte. It was confirmed that some factors, such as oocytein vitromaturation, are detectable at the molecular level of human oocytes and their polar bodies in terms of gene expression profile. Furthermore, the first genetic evaluations of oocyte-like cells developedin vitrofrom human stem cells of different origin were performed showing that these cells express some genes related to oocytes. All these findings provide some new knowledge and clearer insights into oocyte quality and oogenesis that might be introduced into clinical practice in the future.
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Němeček, David, Markéta Dvořáková, Ivona Heroutová, Eva Chmelíková, and Markéta Sedmíková. "Anti-apoptotic properties of carbon monoxide in porcine oocyte duringin vitroaging." PeerJ 5 (October 6, 2017): e3876. http://dx.doi.org/10.7717/peerj.3876.

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If fertilization of matured oocyte does not occur, unfertilized oocyte undergoes aging, resulting in a time-dependent reduction of the oocyte’s quality. The aging of porcine oocytes can lead to apoptosis. Carbon monoxide (CO), a signal molecule produced by the heme oxygenase (HO), possesses cytoprotective and anti-apoptotic effects that have been described in somatic cells. However, the effects of CO in oocytes have yet to be investigated. By immunocytochemistry method we detected that both isoforms of heme oxygenase (HO-1 and HO-2) are present in the porcine oocytes. Based on the morphological signs of oocyte aging, it was found that the inhibition of both HO isoforms by Zn-protoporphyrin IX (Zn-PP IX) leads to an increase in the number of apoptotic oocytes and decrease in the number of intact oocytes during aging. Contrarily, the presence of CO donors (CORM-2 or CORM-A1) significantly decrease the number of apoptotic oocytes while increasing the number of intact oocytes. We also determined that CO donors significantly decrease the caspase-3 (CAS-3) activity. Our results suggest that HO/CO contributes to the sustaining viability through regulation of apoptosis duringin vitroaging of porcine oocytes.
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Liu, Rui-Hua, Yong-Hai Li, Li-Hong Jiao, Xiao-Ning Wang, Hong Wang, and Wei-Hua Wang. "Extracellular and intracellular factors affecting nuclear and cytoplasmic maturation of porcine oocytes collected from different sizes of follicles." Zygote 10, no. 3 (August 2002): 253–60. http://dx.doi.org/10.1017/s0967199402002332.

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Nuclear and cytoplasmic maturation of porcine oocytes collected from different sizes of follicles were examined. Oocyte-cumulus complexes were collected from small (1-2 mm in diameter), medium (3-6 in diameter) and large (7-8 mm in diameter) follicles and cultured in a modified tissue culture medium 199 for 44 h. Nuclear maturation was evaluated after orcein staining, and cytoplasmic maturation was evaluated by intracellular glutathione (GSH) assay. Oocyte diameter, cumulus morphology, steroid hormones and glutathione in the follicular fluid (FF), were also examined. Significantly higher proportions of oocytes collected from large and medium follicles reached metaphase II than did oocytes from small follicles. Oocytes from small follicles also had a smaller size. GSH content was significantly higher (p < 0.05) in oocytes from large (14.24 ± 2.1 pmol/oocyte) and medium (13.69 ± 1.5 pmol/oocyte) follicles than in oocytes from small (9.44 ± 1.28 pmol/oocyte) follicles just after collection. After maturation, oocytes from medium follicles had a higher GSH concentration than oocytes from small follicles. It was found that between 49.7 ± 5.18 nM and 52.25 ± 0.78 nM GSH was present in FF but there was no statistical difference between follicle sizes. A significantly higher (p < 0.001) estradiol level was present in FF from large follicles (299.2 ± 68.6 ng/ml) than from medium (40.0 ± 6.4 ng/ml) and small (41.2 ± 3.7 ng/ml) follicles. Progesterone concentrations in FF from large (281.6 ± 45.9 ng/ml) and medium (267.5 ± 38.6 ng/ml) follicles were significantly higher than that (174.7 ± 22.0 ng/ml) from small follicles. These results indicate that the oocyte's ability to accumulate intracellular GSH during maturation, and extracellular steroid hormones and cumulus cells, affect the competence of porcine oocytes to undergo nuclear and cytoplasmic maturation.
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Zuccotti, Maurizio, Anna Piccinelli, Nicola Marziliano, Silvia Mascheretti, and Carlo Alberto Redi. "Development and loss of the ability of mouse oolemma to fuse with spermatozoa." Zygote 2, no. 4 (November 1994): 333–39. http://dx.doi.org/10.1017/s096719940000215x.

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SummaryTo further our Knowledge on the mechanisms and molecules involved in mouse sperm–oocyte plasma membrane interaciton, exteraction, experiments were carried out to determine the stage during oogenesis at which an oocte acquires the capacity ot fuse with acrosome-reacted sperm. Zona-ferr oocytes 10 μm in diametes do not fuse with sperm. Oolemma fusibility is first acquired when the oocyte reaches about 20μm in diameter. Fusibility is maniatained even after fertilisation has accurred and is lost completely by the 4–cell stage.
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Talreja, Deepa, Chirag Gupta, Hrishikesh Pai, and Nandita Palshetkar. "Oocyte Vitrification: A Comparative Analysis Between Fresh and Cryopreserved Oocytes in an Oocyte Donation Program." Fertility & Reproduction 02, no. 01 (March 2020): 9–13. http://dx.doi.org/10.1142/s2661318220500024.

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Background: Oocyte Cryopreservation has become an important part of infertility treatment for various reasons such as fertility preservation in women going for oncological treatment; in oocyte donation cycles; in eliminating several religious, ethical, and legal concerns of embryo freezing and in women who wish to delay childbirth. The newer ”vitrification” technique for freezing has further improved the success rates for actual conception than the earlier method of slow freezing. A successful oocyte freezing program can help in establishment of oocyte banks, which would help to provide compatible oocytes immediately, thus would eliminate the several problems of fresh donor cycles. Methods: In this retrospective observational study, total 60 oocyte donation cycles were included (38 were fresh and 22 were vitrified oocytes cycle, respectively). After a thorough screening, controlled ovarian hyperstimulation for donors was performed using flexible antagonist protocol. All mature oocytes were allocated into “vitrified oocytes” and “fresh oocytes” groups. Vitrification technique using Cryotop method was used for oocyte freezing. Both clinical and laboratory outcomes of vitrified and fresh oocytes in donor cycles were compared. Results: A total of 600 oocytes (226 “vitrified oocytes” and 374 fresh oocytes), were studied. After warming 218 oocytes survived resulting in survival rate of 96.4%. Fertilization rate and embryo formation rate was 86.2% and 93.6%, respectively. Results of frozen-thawed oocyte donor cycles were compared with fresh donation cycles. For fresh oocyte group, fertilization rate and embryo formation rate was 83.4% and 92.6%, respectively. On comparing clinical outcomes, clinical pregnancy rate was 60.5% in fresh group and 63.6% in vitrified group. Conclusions: Both clinical and laboratory results obtained in the study suggest that oocyte cryopreservation can be performed with reproducible success, thus vitrification technique can be provided as a useful tool for achieving highly successful outcomes in an oocyte donor program.
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Tharasanit, T., S. Colleoni, G. Lazzari, B. Colenbrander, C. Galli, and T. A. E. Stout. "Effect of cumulus morphology and maturation stage on the cryopreservability of equine oocytes." Reproduction 132, no. 5 (November 2006): 759–69. http://dx.doi.org/10.1530/rep.1.01156.

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Oocyte cryopreservation is a potentially valuable way of preserving the female germ line. However, the developmental competence of cryopreserved oocytes is presently poor. This study investigated whether the morphology of the cumulus complex surrounding an immature equine oocyte and/or the oocyte’s stage of maturation affect its cryopreservability. Compact (Cp) and expanded (Ex) cumulus oocyte complexes (COCs) were vitrified either shortly after recovery (germinal vesicle stage, GV) or after maturation in vitro (IVM); cryoprotectant-treated and -untreated non-frozen oocytes served as controls. In Experiment I, oocytes matured in vitro and then vitrified, or vice versa, were examined for maturation stage and meiotic spindle quality. Cp and Ex COCs vitrified at the GV stage matured at similar rates during subsequent IVM (41 vs 46% MII), but meiotic spindle quality was better for Cp than Ex (63 vs 33% normal spindles). Vitrifying oocytes after IVM resulted in disappointing post-warming spindle quality (32 vs 28% normal for Cp vs Ex). In Experiment II, oocytes from Cp and Ex COCs vitrified at the GV or MII stages were fertilized by intracytoplasmic sperm injection (ICSI) and monitored for cleavage and blastocyst formation. Oocytes vitrified prior to IVM yielded higher cleavage rates (34 and 27% for Cp and Ex COCs) than those vitrified after IVM (16 and 4%). However, only one blastocyst was produced from a sperm-injected vitrified–warmed oocyte (0.4 vs 9.3% and 13% blastocysts for cryoprotectant-exposed and -untreated controls). It is concluded that, when vitrification is the chosen method of cryopreservation, Cp equine COCs at the GV stage offer the best chance of an MII oocyte with a normal spindle and the potential for fertilization; however, developmental competence is still reduced dramatically.
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More sources

Dissertations / Theses on the topic "Oocyte"

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Kazem, Rahnuma. "Oocyte cryopreservation." Thesis, University of Aberdeen, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282706.

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A questionnaire based survey was done to assess the views of fertile individuals, infertile individuals, egg donors and recipients towards gamete donation. The survey showed that fertile individuals were significantly less inclined towards the use of donated eggs in research and treatment, compared to infertile individuals. Acceptability of gamete donation was found to be very high in all groups regardless of their fertility, but the majority of individuals, whether fertile or infertile, were opposed to the use of fetal and cadaveric sources of obtaining eggs. The effect of modifications of the freeze-thaw process was investigated in the mouse model. It was seen that slight modifications of the slow freeze protocol affected survival rates and that ultrarapid freezing achieved better survival rates than slow freezing. Human oocyte cryopreservation was performed using a slow freeze-rapid thaw protocol. In total, 34.4% of oocytes survived cryopreservation and these were randomly allocated for fertilisation by conventional in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI). Resulting embryos were spread for chromosomal analysis. ICSI significantly improved the rates of normal fertilisation (43.2% versus 2.7%) compared to IVF (P<0.001). A normal diploid karyotype was achieved by ICSI. These studies show that oocyte donation is acceptable to the majority of both fertile and infertile individuals. Further research is required to improve the methods of oocyte cryopreservation. Once the techniques of cryopreservation have been established, ICSI may successfully be applied to enhance subsequent fertilisation rates.
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Marsh, Adam. "Oocyte-follicle interactions." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12684/.

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The ovarian follicle is an individual functional unit that provides the optimal environment for the oocyte within to develop. This thesis outlines the research in the field of ovarian follicular dynamics that has already been established, and further develops these findings to explore in greater detail the relationship between the oocyte and its environment, both in an in vitro and in vivo setting, using a variety of species. The first major research area involved studying the role of oocyte-secreted factors, which was examined using a series of dose response experiments. These were performed using an ovine granulosa cell culture model, and elucidated a possible role for a collaborative action of BMP15 and GDF9 in the promotion of oestradiol synthesis, while inhibiting production of progesterone in this species. This finding was then further investigated using an ovine in vivo immune-neutralisation study, the endocrine and histological results of which confirmed these findings in a proportion of these animals, although this study was limited by the animals appearing to have been in seasonal anoestrus. The second major topic that was investigated was based around the ovarian microenvironment, in terms of angiogenesis and hypoxia. Again, ovine granulosa cell cultures were used, in this instance to examine the effect of hypoxic conditions on steroid hormone production. These experiments indicated that somatic cell steroid hormone production is likely to be compromised by a hypoxic environment, and therefore that the provision of oxygen through a local blood supply may be a vital requirement for these cells. To investigate the relevance of studying ovarian blood supply and physiology in a clinical setting, perfusion studies were carried out based on a series of bovine phantom experiments, which were used to study the effect of varying flow rate on the parameters routinely measured using this technology. The routine clinical ultrasonographic methods of ovarian assessment such as 4D ViewTM, SonoAVCTM and VOCAL were also examined, based on bovine phantom experiments, revealing possible weaknesses in the data provided by ultrasound that are increasingly relied upon in the clinical setting. Finally, a clinical trial was carried out to try and encompass all of the findings of the in vitro and in vivo work, in order to place these theories into context in a human IVF setting. This work was unfortunately limited severely by a lack of patient numbers, but some interesting results were observed with regard to oocyte developmental potential relationships with follicular fluid and somatic cell factors, as well as ultrasound measures of peri-follicular blood supply.
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Wang, Ling. "Mouse oocyte maturation: How similar is it to frog oocyte maturation?" Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/27075.

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In this study, I have attempted to address the similarities/differences between amphibian and mouse oocytes by focusing on two aspects of mouse oocyte maturation. In the first project, I investigated the ability of several antagonists of serotonin receptors to initiate follicle-enclosed mouse oocytes to undergo maturation. I demonstrated that ritanserin, but not any others, was capable of inducing oocyte maturation in the intact mouse follicles. Significantly, ritanserin is also capable of inducing frog oocyte maturation, as demonstrated by others in our lab. These results therefore suggested that a similar cAMP-elevating G protein coupled receptor, the target of ritanserin, is responsible for maintaining prophase arrest in both frog and mouse oocytes. In the second project, I have investigated the ability brefeldin A (BFA), a specific inhibitor of a small G protein ARF1, to initiate mouse oocyte maturation, as it has been suggested that BFA is capable of inducing frog oocyte maturation. I demonstrated that BFA indeed was as potent as human chorionic gonadotropin (HCG) to initiate follicle-enclosed oocytes to undergo germinal vesicle breakdown. However, BFA-treated oocytes failed to complete maturation and, instead, were arrested at metaphase I with apparently normal bipolar spindles. We further demonstrated a dominant negative mutant of ARF1 (ARF1-T31N-HA) similarly arrested the maturing oocytes at metaphase I. These studies helped reinforce the idea that oocyte maturation is fundamentally the same in mammals as it is in amphibians. The experimentally observed differences may not be very significant biologically. This concept will be discussed in conjunction with recently published literature. (Abstract shortened by UMI.)
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Pfender, Sybille Helen. "Studies of asymmetric oocyte division and new genes controlling oocyte maturation." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648232.

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Yang, Min. "Evaluation of Oocyte Developmental Competence and Potential Strategies to Improve Oocyte Quality." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/6914.

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Assisted reproductive technologies (ARTs) have now been extensively used to promote reproductive efficiency as a fertility treatment not only in human medicine but also animal reproduction. ARTs serve as an important tool to advance the fundamental knowledge of reproductive processes. The quality of female’s eggs defines its ability to undergo maturation, fertilization, and development. This quality is determined by various factors and is crucial for the success of ARTs. Any alternations happening during the egg growth and maturation process can result in the decreased quality, which could have long-lasting effects on development. Improving the developmental efficiency of the egg is quite challenging due to the limited knowledge on the underlying mechanism of how the egg regulates biological processes during the growth and maturation phase. We compared good-quality and poor-quality eggs to detect the key players in determining the egg quality at the molecular level. Our finding also provides information that benefits the understanding of how the nutrients in culture medium facilitate oocyte maturation, which will eventually help optimize the condition for oocyte culture. Based on the results from these comparative studies, we proposed a potential strategy for improving egg quality. The knowledge obtained from our research offers promise for many applications in the treatment of infertility and improvement of ART efficiency.
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Abdelsalam, Selima Mohamed. "Impact of oocyte vitrification." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/impact-of-oocyte-vitrification(d112e86b-faac-4b95-abff-06934e923ebd).html.

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Safe and effective oocyte cryopreservation will have a considerable impact on clinical practice in assisted reproduction. Great improvements have been made in recent years to oocyte vitrification procedures, although further controlled trials are necessary to ensure safety, and it is necessary to know more about pregnancy and live birth outcomes. This study aims to validate various methods of oocyte vitrification as assessed by comparative target gene analysis, hence contributing to information available to clinicians advising women about fertility preservation options before cancer treatment. Target genes investigated were: the maternal effect genes Deleted in Azoospermia Like (DAZL), Maternal Antigen That Embryos Require (MATER/NLRP5) and Zygote Arrest 1 (ZAR1); three genes involved in cell cycle progression and cell death, tumour suppressor protein 53 (p53), B-cell lymphoma 2 (BCL2), BCL2-Associated X Protein (BAX); three genes known to affect spindle and chromatin structure, oocyte-specific histone 1 (H1FOO), kinesin family member 11 (KIF11) and mitotic arrest deficient 2 (MAD2); together with Factor In the GermLine, Alpha (FIGLα) which regulates zona pellucida proteins, octamer-binding transcription factor 4 (OCT4/POU5F1) which is associated with pluripotency and oocyte developmental competence, and superoxide dismutase 2, mitochondrial (SOD2) which responds to oxidative stress in the mitochondria. These genes may be useful indicators of oocyte quality following vitrification. Lysis, complementary DNA (cDNA) amplification, polyadenylic acid polymerase chain reaction (polyA PCR) and quantitative polymerase chain reaction (QPCR) were used to investigate gene expression patterns in failed-to-fertilize non-vitrified, vitrified and slow frozen human MII oocytes. Comparative gene analyses included oocytes vitrified using closed and open carriers, and two different media. Results indicate that the impact of vitrification varies by gene and oocyte variability, highlighting the importance of studies based on single oocytes and the need for caution in interpretation of generalised findings. OCT4 and also β-actin were significantly affected by all methods investigated, while FIGLα, MAD2, ZAR1 and DAZL were affected by some methods. Oocyte survival rate after thawing and the number of genes expressed by individual oocytes were higher with media incorporating dimethyl sulfoxide (DMSO) and Dextran Serum Supplement (DSS) and first-step warming in a larger volume. All methods led to altered expression of target genes, most noticeably when the second media was used. Further quantitative studies of the impact of OCT4, FIGLα and β-actin should be conducted, together with clinical comparisons between media and a longitudinal multi-centre study regarding outcomes arising from different vitrification methods.
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Davies, S. "Oocyte maturation in mice." Thesis, University of Essex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377928.

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Cox, Lindsay. "Oocyte Quality: Molecular Constituents Altered in the Oocyte Due to Various Environmental Factors." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5042.

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An estimated 1.6 million American couples struggle with infertility. Some causes for poor fertility can be clearly defined but in many instances, subfertility is unexplained. Poor oocyte quality is now considered to be a main contributing factor for many causes of infertility. Good oocyte quality is crucial for many processes including embryo development and maintaining pregnancy. There is a possibility that any alterations to the oocyte can have long lasting effects on embryo development and the health of the offspring. The oocyte is very sensitive to any perturbations to its surrounding environment. Transcripts for apoptosis inhibitors and epigenetic modifiers were found to be significantly more abundant in in vivo-matured oocytes compared to oocytes that were matured in vitro. RNA degradation and chromatin remodeling pathways may also be perturbed in in vitro-matured oocytes. While examining the effects of maternal age on the oocyte, there are age-related differences in gene expression in equine cumulus-oocyte complexes. Differences in gene expression may lead to a decrease in oocyte developmental competence. Age related alterations to gene expression in the equine cumulus-oocyte complexes might be caused by increased rates of oxidative stress and subsequent DNA damage. These alterations could directly impact many processes within the oocyte. Higher incidences of apoptosis may be possible in the cumulus cells from aged mares, which would directly impact the developmental competence of the oocyte. Lastly, oocyte quality may be impacted by western dietary consumption patterns, which could lead to many genes being differentially expressed in oocytes. Alterations to the abundance of these genes have been shown to lead to effects that are commonly seen with metabolic syndrome, such as glucose intolerance, insulin resistance, obesity and diabetes. The results of this work will ultimately provide insight into the effects environmental influences have on the oocyte at the molecular level.
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Weingarten, Lisa Suzanne. "The oocyte-to-embryo transition : regulation of oocyte maturation and egg activation in Drosophila." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79191.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Biology, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 33-39).
In oogenesis, meiosis must be highly regulated to ensure that growth of the oocyte and chromosomal segregation are coordinated properly. To do this, meiosis arrests at two points to permit oocyte differentiation and coordination with fertilization. In Drosophila, the first arrest in prophase I is released by oocyte maturation, and the second arrest in metaphase I is released by egg activation. This thesis explores mechanisms controlling these two processes. First, the putative role of the Deadhead (DHD) thioredoxin in Drosophila female meiosis is examined. Possible roles that DHD may play in DNA replication, ROS/RNS redox pathways, and vitelline membrane crosslinking are explored. Furthermore, current research into the role of Ca²+ as a regulator of Drosophila egg activation is summarized. Recent studies have suggested that Sarah (Sra), a regulator of Calcineurin (CN), is required for egg activation and meiotic completion. A model for Sra/CN signaling is presented, highlighting the role of Ca²+ in Drosophila activation, and emphasizing aspects of meiotic activation conserved across species. Finally, proteins recovered from a large-scale proteomic screen undertaken by our lab are discussed. This screen identified proteins that increase or decrease significantly during the processes of maturation and activation through quantitative mass spectrometry. Pairwise comparison of protein levels between pre- and post- maturation oocytes (stage 10 vs. stage 14 oocytes) or pre- and post-activation eggs (stage 14 vs. unfertilized eggs) identified candidate proteins up- and downregulated during one or both of these processes. These candidates include proteins involved in calcium binding and transport, the ubiquitination pathway, steroid biosynthesis and metabolism, and a gap junction protein. Additional characterization of these proteins may provide further insight into the regulation of Drosophila maturation and activation.
by Lisa Suzanne Weingarten.
S.M.
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Duffié, Rachel. "Epigenetic inheritance from the oocyte." Paris 6, 2013. http://www.theses.fr/2013PA066077.

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La méthylation de l’ADN est essentielle pour le développement des mammifères. Cette marque épigénétique peut être héritée des gamètes parentaux et influencer les phénotypes dans la descendance, un phénomène reconnu sous le nom d’empreinte parentale lorsque la transmission se fait de manière asymétrique depuis l’ovocyte et le spermatozoïde. Mon travail de thèse a concerné la méthylation spécifiquement héritée de l’ovocyte chez le modèle murin. J’ai tout d’abord montré que la méthylation ovocytaire est globalement dépendante du cofacteur d’ADN méthyltransférase DNMT3L. De manière importante, j’ai mis en évidence de nouvelles formes d’empreinte héritées de l’ovocyte, maintenues de manière tissu-spécifique ou très transitoirement au cours du développement. Le gène Cdh15 est soumis à une empreinte tissu-spécifique : la méthylation maternelle est maintenue et conduit à l’expression paternelle d’un transcrit alternatif uniquement dans l’hypothalamus. J’ai également identifié un ARN régulateur au locus Gpr1/Zdbf2 comme soumis à une empreinte maternelle transitoire : son expression mono-allélique très brève dans l’embryon péri-implantatoire induit en cis des marques de méthylation permanentes associées à l’expression paternelle de Zdbf2 tout au long de la vie. Ces découvertes ouvrent des perspectives nouvelles quant à la régulation spatio-temporelle de l’empreinte parentale
DNA methylation is essential for mammalian development. Genomic imprinting regulates parent-of-origin phenotypes through differential gametic inheritance of DNA methylation at imprinting control regions, ICRs, which is maintained in the progeny ubiquitously and lifelong. During my PhD, I focused on DNA methylation inherited from the oocyte using the mouse model. I found that DNMT3L is required for global oocyte methylation. I also provide evidence for new forms of imprinting, demonstrating that maternal imprints can be maintained in a tissue-specific manner or very transiently during development. The Cdh15 gene is subject to tissue-specific imprinting: maternal-specific methylation is maintained in the hypothalamus where it leads to paternal expression of an alternative transcript. I also identified a regulatory RNA at the Gpr1/Zdbf2 locus under the control of a transient maternal imprint. Its brief monoallelic expression in the periimplantation embryo is associated with establishment of permanent methylation marks in cis and subsequent lifelong paternal expression of neighboring Zdbf2. These findings provide new perspectives about the permanency and regulation of genomic imprinting in mammals
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Books on the topic "Oocyte"

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Homer, Hayden A., ed. Mammalian Oocyte Regulation. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-191-2.

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Verlhac, Marie-Hélène, and Marie-Emilie Terret, eds. Mouse Oocyte Development. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-8603-3.

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Babin, Patrick J., Joan Cerdà, and Esther Lubzens, eds. The Fish Oocyte. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6235-3.

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G, Grudzinskas J., and Yovich John, eds. Gametes: The oocyte. Cambridge: Cambridge University Press, 1995.

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Dettlaff, T. A., S. G. Vassetzky, and Frank Billett, eds. Oocyte Growth and Maturation. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4684-0682-5.

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Antonovna, Detlaf Tatʹi͡a︡na, Vassetzky S. G, and Billett F. S, eds. Oocyte growth and maturation. New York: Consultants Bureau, 1988.

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Kim, S. Samuel, ed. Oocyte Biology in Fertility Preservation. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-8214-7.

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Malvasi, Antonio, and Domenico Baldini, eds. Pick Up and Oocyte Management. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-28741-2.

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Eppig, J., Ch Hegele-Hartung, and M. Lessl, eds. The Future of the Oocyte. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-662-04960-0.

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Patrizia, Ciotti, and Venturoli Stefano, eds. Handbook of human oocyte cryopreservation. Cambridge: Cambridge University Press, 2013.

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Book chapters on the topic "Oocyte"

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Oppenheimer, Anne, and Renato Fanchin. "Oocyte Retrieval." In Managing Ultrasonography in Human Reproduction, 171–79. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-41037-1_10.

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Borini, Andrea, and Veronica Bianchi. "Oocyte Cryopreservation." In Fertility Preservation in Females, 329–34. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-5617-9_20.

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Borini, Andrea, and Veronica Bianchi. "Oocyte Cryopreservation." In Fertility Preservation in Females, 111–32. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-5617-9_8.

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Rosenwaks, Zev. "Oocyte Donation." In Technology and Infertility, 223–33. New York, NY: Springer New York, 1993. http://dx.doi.org/10.1007/978-1-4613-9205-7_21.

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Maggiulli, Roberta, Filippo Ubaldi, and Laura Rienzi. "Oocyte Denuding." In Practical Manual of In Vitro Fertilization, 93–104. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-1780-5_12.

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Cobo, Ana. "Oocyte Vitrification." In Practical Manual of In Vitro Fertilization, 523–28. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-1780-5_57.

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Borini, Andrea, and Veronica Bianchi. "Oocyte Cryopreservation." In Fertility Preservation, 371–74. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-1783-6_29.

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Borini, Andrea, and Veronica Bianchi. "Oocyte Cryopreservation." In Fertility Preservation, 89–105. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-1783-6_8.

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Rienzi, Laura Francesca, Roberta Maggiulli, and Filippo Maria Ubaldi. "Oocyte Denuding." In In Vitro Fertilization, 133–45. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-43011-9_14.

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Schulman, Joseph. "Oocyte Development." In Preimplantation Genetics, 11–14. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4684-1351-9_2.

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Conference papers on the topic "Oocyte"

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Bugaev, L. A., A. V. Voykina, and S. G. Sergeeva. "SPECIAL FEATURES OF OOCYTE SIZE IN SO-IUY MULLET (PLANILIZA HAEMATOCHEILA TEMMINCK & SCHLEGEL, 1845) IN THE SEA OF AZOV AT THE END OF THE WINTER SEASON, 2019." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS Volume 2. DSTU-Print, 2020. http://dx.doi.org/10.23947/interagro.2020.2.449-453.

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Analysis of special features of the reproductive system of so-iuy mullet Planiliza haematocheila (Temminck & Schlegel, 1845) females from the Azov and Black Sea Basin at the end of the winter season, 2019, has been conducted using the size of oocytes as its basis. Individual differences in distribution of oocyte sizes during the period of trophoplazmatic growth have been identified. Following the estimation of ordered series of oocyte sizes during the period of trophoplazmatic growth, the median and percentile values have been calculated; they can be used as reference values for qualitative characterization of ordered series for oocyte diameter in an individual specimen, using the empirical median, calculated for the respective specimen, as a basis. It has been found out that the sizes of trophoplazmatic growth oocytes, which are utilized during the spawning period of the current year, and, therefore, the degree of gonad maturity have individual characteristics independent of the age of an individual, of its length and weight, and of the content of reserve and bioactive substances in its tissues and blood.
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Amaral, Marcello Magri, Aixia Sun, Yilin Li, Ping Wang, Zexu Jiao, and Chao Zhou. "Study of Mice Ovaries using Optical Coherence Tomography." In Latin America Optics and Photonics Conference. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/laop.2022.tu1b.5.

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We investigate the age-related follicle and oocyte morphological differences using Optical Coherence Tomography (OCT). The oocyte’s development stages were observed and discussed. OCT technique can provide a real-time imaging tool for future ovarian tissue characterization.
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Wang, Boru. "Research on vitro oocyte maturation technology and factors affecting oocyte maturation." In Third International Conference on Biological Engineering and Medical Science (ICBioMed2023), edited by Alan Wang. SPIE, 2024. http://dx.doi.org/10.1117/12.3012934.

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Feng, Zeyang, Qili Zhao, Yaowei Liu, Mingzhu Sun, Xiangfei Zhao, Maosheng Cui, and Xin Zhao. "Augmented Reality-Based Precise Oocyte Enucleation." In 2019 IEEE 19th International Conference on Nanotechnology (IEEE-NANO). IEEE, 2019. http://dx.doi.org/10.1109/nano46743.2019.8993940.

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"The Effects of Omega3 on Oocyte Maturation." In Aug. 8-9, 2017 Singapore. EIRAI, 2017. http://dx.doi.org/10.17758/eirai.f0817214.

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Cao, Yuan, Julia Floehr, Danyil Azarkh, and Uwe Schnakenberg. "Mouse Oocyte Characterization by Electrical Impedance Spectroscopy." In 2022 IEEE Sensors. IEEE, 2022. http://dx.doi.org/10.1109/sensors52175.2022.9967210.

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Abbasi, Ali A., M. T. Ahmadian, Ali Alizadeh, and S. Tarighi. "Application of Hyperelastic Models in Mechanical Properties Prediction of Mouse Oocyte and Embryo Cells at Large Deformations." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65034.

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Biological cell studies have many applications in biology, cell manipulation and diagnosis of diseases such as cancer and malaria. In this study, inverse finite element method (IFEM) combined with Levenberg-Marquardt optimization algorithm has been used to extract and characterize material properties of mouse oocyte and embryo cells at large deformations. Then, the simulation results have been validated using data from experimental works. In this study, it is assumed cell material is hyperelastic, isotropic, homogenous and axisymmetric. For inverse analysis, FEM model of cell injection experiment which implemented in Abaqus software has been coupled with Levenberg-Marquardt optimization algorithm written in Matlab; based on this coupling the optimum hyperelastic coefficients which give the best match between experimental and simulated forces are extracted. Results show that among different hyperelastic material models, Ogden material is well suitable for characterization of mouse oocyte cell and Mooney-Rivlin or polynomial are suitable for characterization of mouse embryo cell. Moreover the evaluated Poisson ratio of the cell is obtained to be equal to 0.5, which indicates the structural material of mouse oocyte and embryo, are compressible.
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Yamanishi, Yoko, Shinya Sakuma, and Fumihito Arai. "Magnetically Modified Soft Micro Actuators for Oocyte Manipulation." In 2007 International Symposium on Micro-NanoMechatronics and Human Science. IEEE, 2007. http://dx.doi.org/10.1109/mhs.2007.4420896.

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Kabadayı, Hilal. "The role of trophoblastic items in oocyte culture." In 15th International Congress of Histochemistry and Cytochemistry. Istanbul: LookUs Scientific, 2017. http://dx.doi.org/10.5505/2017ichc.op-02.

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Pokrzywnicka, Aleksandra, Danylo Lizanets, Rafal Walczak, and Patrycja Sniadek. "Lab-on-chip for Mechanical Characterization of Oocyte." In 2018 25th International Conference "Mixed Design of Integrated Circuits and System" (MIXDES). IEEE, 2018. http://dx.doi.org/10.23919/mixdes.2018.8436939.

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Reports on the topic "Oocyte"

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Hansen, Peter J., Zvi Roth, and Jeremy J. Block. Improving oocyte competence in dairy cows exposed to heat stress. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598163.bard.

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Original Objectives. The overall goal is to develop methods to increase pregnancy rate in lactating dairy cows exposed to heat stress through methods that minimize damage to the oocyte and embryo caused by heat stress. Objectives were as follows: (1) examine the protective effects of melatonin on developmental competence of oocytes exposed to elevated temperature in vitro; (2) test whether melatonin feeding can improve developmental competence of oocytes in vivo and, if so, whether effects are limited to the summer or also occur in the absence of heat stress; and (3) evaluate the effectiveness of improving fertility by facilitating follicular turnover in the summer and winter. Revised Objectives. (1) Examine protective effects of melatonin and follicular fluid on developmental competence of oocytes exposed to elevated temperature in vitro; (2) examine the protective effects of melatonin on developmental competence of embryos exposed to elevated temperature in vitro; (3) evaluate effectiveness of improving fertility by administering human chorionicgonadotropin (hCG) to increase circulating concentrations of progesterone and evaluate whether response to hCG depends upon genotype for four mutations reported to be related to cow fertility; and (4) identify genes with allelic variants that increase resistance of embryos to heat shock. Background. The overall hypothesis is that pregnancy success is reduced by heat stress because of damage to the oocyte and cleavage-stage embryo mediated by reactive oxygen species (ROS), and that fertility can be improved by provision of antioxidants or by removing follicles containing oocytes damaged by heat stress. During the study, additional evidence from the literature indicated the potential importance of treatment with chorionicgonadotropin to increase fertility of heat- stressed cows and results from other studies in our laboratories implicated genotype as an important determinant of cow fertility. Thus, the project was expanded to evaluate hCG treatment and to identify whether fertility response to hCG depended upon single nucleotide polymorphisms (SNP) in genes implicated as important for cow fertility. We also evaluated whether a SNP in a gene important for cellular resistance to heat stress (HSPA1L, a member of the heat shock protein 70 family) is important for embryonic resistance to elevated temperature. Major conclusions, solutions & achievements. Results confirmed that elevated temperature increases ROS production by the oocyte and embryo and that melatonin decreases ROS. Melatonin reduced, but did not completely block, damaging effects of heat shock on the oocyte and had no effect on development of the embryo. Melatonin was protective to the oocyte at 0.1-1 μM, a concentration too high to be achieved in cows. It was concluded that melatonin is unlikely to be a useful molecule for increasing fertility of heat-stressed cows. Treatment with hCG at day 5 after breeding increased first-service pregnancy rate for primiparous cows but not for multiparous cows. Thus, hCG could be useful for increasing fertility in first-parity cows. The effectiveness of hCG depended upon genotype for a SNP in COQ9, a gene encoding for a mitochondrial-function protein. This result points the way to future efforts to use genetic information to identify populations of cows for which hormone treatments will be effective or ineffective. The SNP in HSPA1L was related to embryonic survival after heat shock. Perhaps, genetic selection for mutations that increase cellular resistance to heat shock could be employed to reduce effects of heat stress on fertility. Implications, both scientific and agricultural. This project has resulted in abandonment of one possible approach to improve fertility of the heat-stressed cow (melatonin therapy) while also leading to a method for improving fertility of primiparous cows exposed to heat stress (hCG treatment) that can be implemented on farms today. Genetic studies have pointed the way to using genetic information to 1) tailor hormonal treatments to cow populations likely to respond favorably and 2) select animals whose embryos have superior resistance to elevated body temperatures.
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Tilly, Jonathan L. Role of Oocyte Loss in Ovarian Surface Mesothelial Cell Transformation. Fort Belvoir, VA: Defense Technical Information Center, December 2004. http://dx.doi.org/10.21236/ada434130.

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Tilly, Jonathan L., and Grant R. MacGregor. Role of Oocyte Loss in Ovarian Surface Mesothelial Cell Transformation. Fort Belvoir, VA: Defense Technical Information Center, November 2002. http://dx.doi.org/10.21236/ada413259.

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Yang, Caixia, Elane C. Wright, Benjamin J. Hale, Aileen F. Keating, and Jason W. Ross. FOXO3 Expression and Function in the Pig Oocyte and Embryo. Ames (Iowa): Iowa State University, January 2013. http://dx.doi.org/10.31274/ans_air-180814-642.

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Tilly, Jonathan L. Role of Oocyte Loss in Ovarian Surface Mesothelial Cell Transformation. Fort Belvoir, VA: Defense Technical Information Center, November 2003. http://dx.doi.org/10.21236/ada424569.

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Yang, Cai-Xia, Elane C. Wright, and Jason W. Ross. DND1 Expression and Function in the Porcine Ovary, Oocyte and Embryo. Ames (Iowa): Iowa State University, January 2012. http://dx.doi.org/10.31274/ans_air-180814-1372.

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Hansen, Peter J., and Zvi Roth. Use of Oocyte and Embryo Survival Factors to Enhance Fertility of Heat-stressed Dairy Cattle. United States Department of Agriculture, August 2011. http://dx.doi.org/10.32747/2011.7697105.bard.

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The overall goal was to identify survival factors that can improve pregnancy success following insemination or embryo transfer in lactating dairy cows exposed to heat stress. First, we demonstrated that oocytes are actually damaged by elevated temperature in the summer. Then we tested two thermoprotective molecules for their effect on oocyte damage caused by heat shock. One molecule, ceramide was not thermoprptective. Another, insulin-like growth factor-1 (IGF) reduced the effects of heat shock on oocyte apoptosis and oocyte cleavage when added during maturation. We also used lactating cows exposed to heat stress to determine whether bovine somatotropin (bST), which increases IGF1 levels in vivo, would improve fertility in summer. Cows treated with bST received a single injection at 3 days before insemination. Controls received no additional treatment. Treatment with bST did not significantly increase the proportion of inseminated cows diagnosed pregnant although it was numerically greater for the bST group (24.2% vs 17.8%, 124–132 cows per group). There was a tendency (p =0.10) for a smaller percent of control cows to have high plasma progesterone concentrations (≥ 1 ng/ml) at Day 7 after insemination than for bST-treated cows (72.6 vs 81.1%). When only cows that were successfully synchronized were considered, the magnitude of the absolute difference in the percentage of inseminated cows that were diagnosed pregnant between bST and control cows was reduced (24.8 vs 22.4% pregnant for bST and control). Results failed to indicate a beneficial effect of bST treatment on fertility of lactating dairy cows. In another experiment, we found a tendency for addition of IGF1 to embryo culture medium to improve embryonic survival after embryo transfer when the experiment was done during heat stress but not when the experiment was done in the absence of heat stress. Another molecule tested, granulocyte-macrophage colony-stimulating factor (GM-CSF; also called colony-stimulating factor-2), improved embryonic survival in the absence of heat stress. We also examined whether heat shock affects the sperm cell. There was no effect of heat shock on sperm apoptosis (programmed cell death) or on sperm fertilizing ability. Therefore, effects of heat shock on sperm function after ejaculation if minimal. However, there were seasonal changes in sperm characteristics that indicates that some of the decrease in dairy cow fertility during the summer in Israel is due to using semen of inferior quality. Semen was collected from five representative bulls throughout the summer (August and September) and winter (December and January). There were seasonal differences in ion concentration in seminal plasma and in the mRNA for various ion channels known to be involved in acrosome reactions. Furthermore, the proportion of sperm cells with damaged acrosomes was higher in post-thaw semen collected in the summer than in its counterpart collected in winter (54.2 ± 3.5% vs. 51.4 ± 1.9%, respectively; P < 0.08Further examination is required to determine whether such alterations are involved in the low summer fertility of dairy cows.
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Wright, Elane C., Cai-Xia Yang, Christopher K. Tuggle, and Jason W. Ross. Heat Stress during Pig Oocyte In Vitro Maturation Impacts Embryonic Development and Gene Expression. Ames (Iowa): Iowa State University, January 2012. http://dx.doi.org/10.31274/ans_air-180814-1373.

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Arav, Amir, John Crowe, and Amihud Borochov. Role of Membranes Thermobehavior in Chilling Injury of Bovine Oocyte as an Important Step Toward Cr yobanking of Female Genome. United States Department of Agriculture, October 2001. http://dx.doi.org/10.32747/2001.7575274.bard.

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Yaron, Zvi, Abigail Elizur, Martin Schreibman, and Yonathan Zohar. Advancing Puberty in the Black Carp (Mylopharyngodon piceus) and the Striped Bass (Morone saxatilis). United States Department of Agriculture, January 2000. http://dx.doi.org/10.32747/2000.7695841.bard.

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Both the genes and cDNA sequences encoding the b-subunits of black carp LH and FSH were isolated, cloned and sequenced. Sequence analysis of the bcFSHb and LHb5'flanking regions revealed that the promoter region of both genes contains canonical TATA sequences, 30 bp and 17 bp upstream of the transcription start site of FSHb and LHb genes, respectively. In addition, they include several sequences of cis-acting motifs, required for inducible and tissue-specific transcriptional regulation: the gonadotropin-specific element (GSE), GnRH responsive element (GRE), half sites of estrogen and androgen response elements, cAMP response element, and AP1. Several methods have been employed by the Israeli team to purify the recombinant b subunits (EtOH precipitation, gel filtration and lentil lectin). While the final objective to produce pure recombinantGtH subunits has not yet been achieved, we have covered much ground towards this goal. The black carp ovary showed a gradual increase in both mass and oocyte diameter. First postvitellogenic oocytes were found in 5 yr old fish. At this age, the testes already contained spermatozoa. The circulating LH levels increased from 0.5 ng/ml in 4 yr old fish to >5ng/ml in 5 yr old fish. In vivo challenge experiments in black carp showed the initial LH response of the pituitary to GnRH in 4 yr old fish. The response was further augmented in 5 yr old fish. The increase in estradiol level in response to gonadotropic stimulation was first noted in 4 yr old fish but this response was much stronger in the following year. In vivo experiments on the FSHb and LHb mRNA levels in response to GnRH were carried out on common carp as a model for synchronom spawning cyprinids. These experiments showed the prevalence of FSHP in maturing fish while LHP mRNA was prevalent in mature fish, especially in females. The gonadal fat-pad was found to originate from the retroperitoneal mesoderm and not from the genital ridge, thus differing from that reported in certain amphibians This tissue possibly serves as the major source of sex steroids in the immature black carp. However, such a function is taken over by the developing gonads in 4 yr old fish. In the striped bass, we described the ontogeny of the neuro-endocrine parameters along the brain-pituitary-gonadal axis during the first four years of life, throughout gonadal development and the onset of puberty. We also described the responsiveness of the reproductive axis to long-term hormonal manipulations at various stages of gonadal development. Most males reached complete sexual maturity during the first year of life. Puberty was initiated during the third year of life in most females, but this first reproductive cycle did not lead to the acquisition of full sexual maturity. This finding indicates that more than one reproductive cycle may be required before adulthood is reached. Out of the three native GnRHs present in striped bass, only sbGnRH and cGnRH II increased concomitantly with the progress of gonadal development and the onset of puberty. This finding, together with data on GtH synthesis and release, suggests that while sbGnRH and cGnRH II may be involved in the regulation of puberty in striped bass, these neuropeptides are not limiting factors to the onset of puberty. Plasma LH levels remained low in all fish, suggesting that LH plays only a minor role in early gonadal development. This hypothesis was further supported by the finding that experimentally elevated plasma LH levels did not result in the induction of complete ovarian and testicular development. The acquisition of complete puberty in 4 yr old females was associated with a rise in the mRNA levels of all GtH subunit genes, including a 218-fold increase in the mRNA levels of bFSH. mRNA levels of the a and PLH subunits increased only 11- and 8-fold, respectively. Although data on plasma FSH levels are unavailable, the dramatic increase in bFSH mRNA suggests a pivotal role for this hormone in regulating the onset and completion of puberty in striped bass. The hormonal regulation of the onset of puberty and of GtH synthesis and release was studied by chronic administration of testosterone (T) and/or an analog of gonadotropin-releasing hormone (G). Sustained administration of T+G increased the mRNA levels of the PLH subunit to the values characteristic of sexually mature fish, and also increased the plasma levels of LH. However, these changes did not result in the acceleration of sexual maturation. The mRNA levels of the bFSH subunit were slightly stimulated, but remained about 1/10 of the values characteristic of sexually mature fish. It is concluded that the stimulation of FSH gene expression and release does not lead to the acceleration of sexual maturity, and that the failure to sufficiently stimulate the bFSH subunit gene expression may underlie the inability of the treatments to advance sexual maturity. Consequently, FSH is suggested to be the key hormone to the initiation and completion of puberty in striped bass. Future efforts to induce precocious puberty in striped bass should focus on understanding the regulation of FSH synthesis and release and on developing technologies to induce these processes. Definite formulation of hormonal manipulation to advance puberty in the striped bass and the black carp seems to be premature at this stage. However, the project has already yielded a great number of experimental tools of DNA technology, slow-release systems and endocrine information on the process of puberty. These systems and certain protocols have been already utilized successfully to advance maturation in other fish (e.g. grey mullet) and will form a base for further study on fish puberty.
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