National Repository of Grey Literature 6 records found  Search took 0.01 seconds. 
Ovarian stimulation and related hyperstimulation syndrome
Pohlová, Nikola ; Komrsková, Kateřina (advisor) ; Ješeta, Michal (referee)
Ovarian stimulation is a key process of assisted reproduction and it helps women in the treatment of infertility. Hormonal ovarian stimulation ensures the growth and development of ovarian follicles. The selected dominant follicle releases an oocyte during ovulation, which is destined for fertilization. In methods of artificial fertilization, multiple follicles are stimulated, and more oocytes are retrieved. The retrieved oocytes are then fertilised in vitro. In this thesis, the benefits and risks of the commonly used stimulation protocols are discussed. The focus is on optimizing stimulation for individual patients, considering their health status, functional ovarian reserve, and individual needs. Special stimulation protocols for patients with polycystic ovary syndrome and for patients with cancer are presented. Ovarian stimulation is also applied to oocyte donors. The most serious risk of ovarian stimulation is ovarian hyperstimulation syndrome. Ovarian stimulation is also used in the rescue of endangered mammalian species or in the breeding of domesticated animals. The study of ovarian stimulation is important for the improvement of reproductive methods in human and veterinary medicine. Key words: follicles, ovarian stimulation, assisted reproduction, ovulation, risks
Endocrine disruptors and their impact on mammalian oocyte developmental competence
Štenglová, Anna ; Němcová, Lucie (advisor) ; Ješeta, Michal (referee)
Endocrine disruptors (EDs) are defined as substances of exogenous origin that disrupt endocrine system. EDs are found in significant amounts in the natural environment, plastic products and flame retardants, leading to unavoidable exposure. Due to their broad effects, several organizations/ conventions aim to regulate their presence in the natural environment and limit, or even eliminate their production. By entering the body, they negatively affect development, reproductive, nervous or immune systems of various animal classes through hormones. Modified hormonal levels are associated not only with fertility issues, but also with physiological abnormalities, osteoporosis, depression or metabolic diseases. EDs affect the female reproductive system through hormonal modifications of the HHG axis, which can lead to an earlier pubertal onset in some cases. Under the influence of EDs, impairments can also be observed in the process of steroidogenesis, development of follicles and oocytes, particularly through meiotic defects, which can lead to premature ovarian failure or infertility. Multiple chemicals disrupt the females reproductive system across several generations through epigenetic effects. This work summarizes knowledge about these ubiquitous substances and their impact on female reproductive...
Male fertility disorders and sperm damage related to COVID-19 disease.
Pikulová, Simona ; Komrsková, Kateřina (advisor) ; Ješeta, Michal (referee)
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the coronavirus disease 2019 (COVID-19), which has spread rapidly worldwide since the end of 2019. The virus causes serious health problems and damage to human organs, especially the lungs, kidneys, brain, heart and testicles, which can be fatal. This work deals with the entry of SARS- CoV-2 virus into the testicles and sperm damage due to infection. Receptors are described in more detail, specifically the membrane receptor ACE2, which mediates the entry of the virus into germ cells (spermatogonia) and somatic testicular cells (Sertoli and Leydig), which express this receptor. In this work, the mechanisms causing infection are described and attention is focused to changes in the signaling pathways due to SARS-CoV-2 and ACE2 binding. Consequently, the presence of the virus leads to hormonal imbalances, local oxidative stress and inflammation, which affect the course of spermatogenesis and can cause pathological conditions of spermatozoa such as motility disorders or DNA fragmentation and thus adversely affect male fertility. Key words: COVID-19, SARS-CoV-2, male infertility, sperm, ACE2
Identifikace genů nezbytně nutných pro normální průběh oplození a preimplantačního vývoje skotu v podmínkách in vitro
Toralová, Tereza ; Kaňka, Jiří (advisor) ; Pěknicová, Jana (referee) ; Ješeta, Michal (referee)
The aim of this work was to find and characterize genes that seem to be important for normal preimplantation development. We characterized three genes in more detail - centromeric protein F (CENPF; mitosin), ubiquitin C-terminal hydrolase-L1 (UCHL1) and nucleophosmin (NPM1; B23; numatrin; NO38). CENPF and nucleophosmin were shown to start their expression at late 8-cell stage, i.e. at major embryonic genome activation (EGA), and were hence supposed to be important during bovine preimplantation development. CENPF plays crucial role during cell division, especially by mediating the interaction of kinetochores and microtubules. Nucleophosmin is a multifunctional nucleolar phosphoprotein, whose most important roles are rRNA processing, chaperoning, ribosome biogenesis and centriole duplication control. Further, we characterized the role of UCHL1 during fertilization of bovine oocytes. UCHL1 is a deubiquitinating enzyme that controls cytoplasmic protein degradation, recycling of free ubiquitin from proteasome products and is involved in regulation of physiological apoptosis. We studied the function of CENPF and nucleophosmin using RNA interference approach. Since UCHL1 protein is very stable, this method is not suitable for studying the UCHL1 function. We thus used two UCHL1 inhibitors that block its...
Effect of hydrogen sulphide on aging of porcine oocytes in vitro
Krejčová, Tereza ; Petr, Jaroslav (advisor) ; Ješeta, Michal (referee)
Unfertilized or parthenogenetically non-activated porcine oocytes matured in vitro conditions are subjected to a process known as aging. During such development, porcine oocytes undergo the complex of the structural and functional changes, which can result in spontaneous parthenogenetic activation, fragmentation or lysis. After three days of culture in our condition, 23% of oocytes remained at the stage of metaphase II, 48% of oocytes were spontaneously parthenogenetically activated, 26% of oocytes were subjected to fragmentation and 3% of oocytes were lysed. The complete suppression of porcine oocyte fragmentation during the process of aging occurred during oocytes cultured in medium with sulphide donor Na2S in concentrations 150 µM and 300 µM. Inhibition of enzymes catalyzing the synthesis of hydrogen sulfide in the oocytes during the process of aging (cystathionine-gamma-lyase and cystathionine beta-synthase), iniciates earlier onset of oocytes fragmentation. The effect of both inhibitors could be completely reversed by using sulphide donor Na2S. The process of aging in porcine oocytes significantly reduces the success of the activation processes. Parthenogenetic activation occurred in 94% of pig oocytes, which were not subjected to aging. The proportion of activated oocytes after exposure to 24...

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