• Clinical and Experimental Reproductive Medicine
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• 제43권2호
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• pp.106-111
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• 2016

Objective: To study the clinical outcomes of single frozen-thawed blastocyst transfer cycles according to the hatching status of frozen-thawed blastocysts. Methods: Frozen-thawed blastocysts were divided into three groups according to their hatching status as follows: less-than-expanded blastocyst (${\leq}EdB$), hatching blastocyst (HgB), and hatched blastocyst (HdB). The female age and infertility factors of each group were evaluated. The quality of the single frozen-thawed blastocyst was also graded as grade A, tightly packed inner cell mass (ICM) and many cells organized in the trophectoderm epithelium (TE); grade B, several and loose ICM and TE; and grade C, very few ICM and a few cells in the TE. The clinical pregnancy and implantation rate were compared between each group. The data were analyzed by either t-test or chi-square analysis. Results: There were no statistically significant differences in average female ages, infertility factors, or the distribution of blastocyst grades A, B, and C in each group. There was no significant difference in the clinical pregnancy and implantation rate of each group according to their blastocyst grade. However, there was a significant difference in the clinical pregnancy and implantation rate between each group. In the HdB group, the clinical pregnancy and implantation rate were similar regardless of the blastocyst quality. Conclusion: There was an effect on the clinical outcomes depending on whether the blastocyst hatched during single frozen-thawed blastocyst transfer. When performing single frozen-thawed blastocyst transfer, the hatching status of the frozen-thawed blastocyst may be a more important parameter for clinical outcomes than the quality of the frozen-thawed blastocyst.

• Reproductive and Developmental Biology
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• 제30권2호
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• pp.75-79
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• 2006

The developmental regulation of the preimplantation mammalian embryos is a fundamental step for preparing the implantation and it may be regulated by several autocrine and paracrine factors including platelet-activating factor. PAF improved the embryonic survival and implantation but its role during blastocyst development is still largely unknown. In this study, the effects and the possible pathway of PAF on developmental regulation of blastocyst to hatching stage were investigated. Developmental pattern in hatching embryo was a concentration-response curve showing maximal activity at 1 nM PAF, with decreasing activity at higher concentrations. $50{\mu}M$ 1-(5-isoquinolimnesulfonyl)-2-methylpiperazinme dihydrochloride (H-7), a PKC inhibitor, inhibited the progression of blastocyst to hatching embryo. In addition H-7 blocked the PAF effects on the blastocyst development. Besides tetradecanoylphorbol acetate (TPA), a PKC activator stimulated development of blastocyst to the hatching stage. These finding revealed that PAF support the blastocyst development to the hatching embryo. Also it is suggested that PAF action pathways in hatching supporting include the PKC signaling pathway.

• Journal of Animal Science and Technology
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• 제59권4호
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• pp.7.1-7.13
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• 2017

Background: Selenium is one of the trace minerals whose deficiency is known to lead to complications of female reproduction. The identified gaps in researches regarding selenium and pregnancy include optimizing the dosage of selenium supplementation, timing of supplementation, finding the best form and type of selenium, and selenium administration combined with other antioxidants. Hence, this study was conceptualized to address one of the identified gaps, that is, to find out the best timing of selenium administration around the time of pregnancy. Specifically, this study aimed to assess the effects of maternal Selenium-supplementation, administered at various stages of periconception period, on murine blastocyst morphology, percent occurrence of good quality blastocysts, and implantation status. Methods: ICR female mice were randomly assigned into the unsupplemented group (Group I) receiving basal diet without selenium, and treatment groups given with $3.0{\mu}g$ selenium-supplement per day during pregestation only (Group II), pregestation-throughout-gestation (Group III) and gestation only (Group IV). Both blastocyst morphology and implantation status were assessed. Results: The morphometric measurements of blastocysts appeared to be unaffected by selenium-supplementation at different stages of periconception. Selenium-supplementation at pregestation only (Group II) and gestation only (Group IV) produced higher percent occurrence of good quality blastocysts and lower percent pre-implantation loss than Group III. Among all the treatment groups, Group III (Selenium-supplementation during pregestation-to-gestation) yielded the lowest quality blastocysts and highest percent pre-implantation loss. Conclusion: Maternal selenium-supplementation during pregestation and gestation stages of the periconception period yielded a high percent occurrence of good quality blastocysts and pre-implantation success.

• Clinical and Experimental Reproductive Medicine
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• 제38권4호
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• pp.179-185
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• 2011

The ultimate function of the endometrium is to allow the implantation of a blastocyst and to support pregnancy. Cycles of tissue remodeling ensure that the endometrium is in a receptive state during the putative 'implantation window', the few days of each menstrual cycle when an appropriately developed blastocyst may be available to implant in the uterus. A successful pregnancy requires strict temporal regulation of maternal immune function to accommodate a semi-allogeneic embryo. To preparing immunological tolerance at the onset of implantation, tight temporal regulations are required between the immune and endocrine networks. This review will discuss about the action of steroid hormones on the human endometrium and particularly their role in regulating the inflammatory processes associated with endometrial receptivity.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2006년도 The 5th Biannual Meeting of Pacific Rim Society for Fertility and Sterility
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• pp.174.1-174.1
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• 2006

• 한국발생생물학회지:발생과생식
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• 제21권4호
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• pp.351-359
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• 2017

Implantation is a highly organized process that involves an interaction between a receptive uterus and a competent blastocyst. In humans, natural fecundity suggests that the chance of conception per cycle is relatively low (~30%) and two-third of lost pregnancies occur because of implantation failure. Defective implantation leads to adverse pregnancy outcomes including infertility, spontaneous miscarriage, intrauterine fetal growth restriction and preeclampsia. With use of advanced scientific technologies, gene expression analysis and genetically-engineered animal models have revealed critical cellular networks and molecular pathways. But, because of ethical restrictions and the lack of a mechanistic experiment, comprehensive steps in human implantation have still not been completely understood. This review primarily focuses on the recent advances in mechanisms of implantation. Because infertility is an emerging issue these days, gaining an understanding the molecular and hormonal signaling pathway will improve the outcome of natural pregnancy and assisted reproductive technology.

• 한국발생생물학회지:발생과생식
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• 제14권1호
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• pp.27-34
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• 2010

A fertilized oocyte can get the competence for implantation through cleavage and stage-specific gene expression. These are under the control of autonomous and exogenous regulators including physiological culture condition. Endogenous and exogenous growth factors are considered as critical regulators of cleaving embryos during travel the oviduct and uterus. In this study, an effort was made to evaluate comprehensively the quality of embryos for implantation, grown in media enriched with EGF and PAF. The study evaluated developmental rates on given time, blastulation and hatching rates, and adhesion rates. Developmental rates of blastocyst to the hatching stage were significantly high in PAF treated group compared to the control in a dose-dependent manner but not in EGF group. Implantation rates were significantly high both PAF and EGF in a dose-dependent manner. H7, a PKC inhibitor, blocked the process of hatching of the blastocysts but combined treatment of EGF and PAF enhanced the hatching and implantation of blastocsyts. Based on these results it is suggested that EGF and PAF support acquirement of implantation competence at blastocyst stage through a PKC pathway.

• Clinical and Experimental Reproductive Medicine
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• 제47권2호
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• pp.85-93
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• 2020

The implantation process is highly complex and difficult to mimic in vitro, and a reliable experimental model of implantation has yet to be established. Many researchers have used embryo transfer (ET) to assess implantation potential; however, ET with pseudopregnant mice requires expert surgical skills and numerous sacrificial animals. To overcome those economic and ethical problems, several researchers have tried to use outgrowth models to evaluate the implantation potential of embryos. Many previous studies, as well as our experiments, have found significant correlations between blastocyst outgrowth in vitro and implantation in utero by ET. This review proposes the blastocyst outgrowth model as a possible alternative to animal experimentation involving ET in utero. In particular, the outgrowth model might be a cost- and time-effective alternative method to ET for evaluating the effectiveness of culture conditions or treatments. An advanced outgrowth model and further culture of outgrowth embryos could provide a subtle research model of peri- and postimplantation development, excluding maternal effects, and thereby could facilitate progress in assisted reproductive technologies. Recently, we found that outgrowth embryos secreted extracellular vesicles containing specific microRNAs. The function of microRNAs from outgrowth embryos should be elucidated in further researches.

• Clinical and Experimental Reproductive Medicine
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• 제25권1호
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• pp.35-41
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• 1998

This study was carried out to investigate the development rates of human embryos co-cultured with cumulus cells to each blastocyst stage. Human zygotes were co-cultured on cumulus cell monolayer in YS medium supplemented with 20% hFF. On day 2, if patient had four or more "good" embryos (regular blastomeres without fragmentation), embryos were further cultured for 72hrs. Blastocysts on day 5 were classified into early blastocyst (ErB), early expanding blastocyst (EEB), middle expanding Blastocyst (MEB), and expanded blastocyst (EdB) on the basis of their morphological aspects of trophectoderm cells and blastocoele. Subsequently, maximum 3 of best blastocysts were transferred in 486 cycles. The results in this study were as follows: Patients who had four or more "good" embryos on day 2 were 498 persons, but patients whose embryos could not be transferred due to failure in development to the blastocyst stage on day 5 were 12 persons (2.4%). The development rate of embryos to the blastocyst stage was 58.2% (2,885/4,957) on day 5, and the rates that developed to the ErB, EEB, MEB, and EdB stage were 15.0% (743/4,957), 14.9% (739/4,957), 14.4% (714/ 4,957), and 13.9% (689/4,957), respectively. Total 1366 blastocysts were transferred in 486 cycles (mean number=2.81). The implantation rate and the ongoing implantation rate obtained by observing the number of G-sac and FHB were 29.9% (409/1,366) and 22.5% (308/1,366), respectively. The clinical pregnancy rate was 51.2% (249/486), and the ongoing pregnancy rate' was 39.1% (190/486). Among women showing ongoing pregnancy, women with singleton were 50% (95/190), women with twin were 37.9% (72/190), and women with triplet were 12.1% (23/190). Although triplet pregnancy rate in this study was high such as 12.1%, because many blastocysts with high viability were produced in our co-culture system using cumulus cells on day 5, we really believe that a multiple pregnancy except twin should not occur by selecting good embryos for maximum two blastocyst transfer. These results demonstrate that autologous cumulus cells may be used for the production of blastocysts with high developmental competence, and the use of autologous cumulus cells to be collected easily, and to be treated conveniently at OPU must be an effective means for obtaining high implantation and pregnancy rate.

• 한국가축번식학회지
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• 제18권2호
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• pp.141-150
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• 1994

전자현미경에 의해 자궁부착 전후의 돼지 수정란의 형태형성 및 분화에 따른 배발생 과정을 검토하였다. 돼지 초기배는 자궁이주후 균일하게 자궁에 배분되기전 약 2~3일간은 자궁각의 proximal portion에 존재하며, 임신 4일째에 할구와 할구의 경계를 상실하는 tight한 gap junction을 가진 상실배로 발달한다. 배반포를 형성하는 시기에 estradiol 17$\beta$는 compact한 상실배를 cavitated blastocyst로 발달을 촉진시키면서, steroid hormone이 이후의 배발생을 지배한다. Hatching의 시기는 교배후 6~7일경 zona pellucida을 둘러사고 있는 glycoprotein의 thinning과 lysis에 의해 이루워지는데, hatching 과정은 embryo의 세포수와 무관하였으며, 이때의 embryo의 직경은 0.5~1.0mm인 것을 본 실험에서 확인하였다. 12일경부터는 embryo는 prostaglandins, IGF-binding protein, retinol binding protein, plasminogen activator등의 단백질이 풍부해 이들 인자가 elongation 개시 후보로 고려될 수 있었다. 또한 이 시기의 embryo는 embryonic disc로 발달시 progesterone과 estrogen을 estradiol 17$\beta$로 전활할 수 있으며, 이러한 변화와 함께 spherical stage로부터 tubular 혹은 filamentous form으로 변형되었다. Estrogen이 임신을 통해 prostagladins의 분비를 uterine lumen에 지시하는지는 알 수 없으나 13일 경을 전후해 conceptus estrogen이 uterine arterial blood flow, uterine vasular permeability을 증가시키는 것으로 나타났으며, 자궁에서 protein과 calcium, PGF2$\alpha$, plasminogen inhibitor를 증가시키는 것으로 나타났다. 이 시기의 자궁 변화와 함께 embryo의 attachment는 trophoblast와 uterine membrane사이의 느슨한 결합에 의해 개시되었으며, 18일경 uterine과 trophoblastic microvili의 interdigitation에 의해 완성된다. 이 시기에 conceptus attachment를 위해 필요한 uterine microvili에서의 glycocalyx의 형성과 endometrial epithelium의 erosion을 야기하기 위해 plasminogen activator을 분비하였으며, 반면 자궁에서 plasminogen 역할을 하는 것은 estrogen이며, blastocyst cell 표면의 lectin binding이 attachment에 중요한 역할을 한다. 이상과 같은 일련의 과정을 거친 초기배는 성공적인 임신으로 유도된다고 본다. 따라서, 본 연구는 이상과 같이 착상을 전후한 시기의 배를 전자현미경에 의해 형태형성의 변화를 특히 착상을 전후해 배 취사율이 높은 시기를 대상으로 분석하였다. 이 분석 시기중 성공적인 착상성공율은 56%(71/126)였다.