• Clinical and Experimental Reproductive Medicine
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• v.36 no.3
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• pp.209-217
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• 2009

Objective: To analyze current issues and to propose alternatives for "the cryopreserved embryos generated before 2005". Methods: The differences in attitude among the stakeholders such as sperm donors, oocyte donors, and IVF clinics were presupposed. We want to forecast the impediments which occur inevitably in the process of "getting the informed consent" and "discarding the cryopreserved embryos generated before 2005". Results: Even though there is a specific guideline for "the cryopreserved embryos generated before 2005" at November 23, 2006, no consensus about the process related to "getting the informed consent" has been made. Conclusion: Unavoidably, it seems to be entering a period of massive discard of "the cryopreserved embryos generated before 2005". This is actually opposed to the intent of the Bioethics and Safety Act, which is to protect human dignity and prevent harm to human beings. We have to make reasonable due process to determine the destiny of "the cryopreserved embryos generated before 2005".

• Clinical and Experimental Reproductive Medicine
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• v.50 no.4
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• pp.244-252
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• 2023

Objective: We evaluated the efficacy of the newly developed optimized in vitro culture (OIVC) dish for cultivating preimplantation mouse embryos. This dish minimizes the need for mineral oil and incorporates microwells, providing a stable culture environment and enabling independent monitoring of individual embryos. Methods: Mouse pronuclear (PN) zygotes and two-cell-stage embryos were collected at 18 and 46 hours after human chorionic gonadotropin injection, respectively. These were cultured for 120 hours using potassium simplex optimized medium (KSOM) to reach the blastocyst stage. The embryos were randomly allocated into three groups, each cultured in one of three dishes: a 60-mm culture dish, a microdrop dish, and an OIVC dish that we developed. Results: The OIVC dish effectively maintained the osmolarity of the KSOM culture medium over a 5-day period using only 2 mL of mineral oil. This contrasts with the significant osmolarity increase observed in the 60-mm culture dish. Additionally, the OIVC dish exhibited higher blastulation rates from two-cell embryos (100%) relative to the other dish types. Moreover, blastocysts derived from both PN zygotes and two-cell embryos in the OIVC dish group demonstrated significantly elevated mean cell numbers. Conclusion: Use of the OIVC dish markedly increased the number of cells in blastocysts derived from the in vitro culture of preimplantation mouse embryos. The capacity of this dish to maintain medium osmolarity with minimal mineral oil usage represents a breakthrough that may advance embryo culture techniques for various mammals, including human in vitro fertilization and embryo transfer programs.

• BMB Reports
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• v.49 no.4
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• pp.197-198
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• 2016

Although three different research groups have reported successful derivations of human somatic cell nuclear transfer-derived embryonic stem cell (SCNT-ESC) lines using fetal, neonatal and adult fibroblasts, the extremely poor development of cloned embryos has hindered its potential applications in regenerative medicine. Recently, however, our group discovered that the severe methylation of lysine 9 in Histone H3 in a human somatic cell genome was a major SCNT reprogramming barrier, and the overexpression of KDM4A, a H3K9me3 demethylase, significantly improved the blastocyst formation of SCNT embryos. In particular, by applying this new approach, we were able to produce multiple SCNT-ES cell lines using oocytes obtained from donors whose eggs previously failed to develop to the blastocyst stage. Moreover, the success rate was closer to 25%, which is comparable to that of IVF embryos, so that our new human SCNT method seems to be a practical approach to establishing a pluripotent stem cell bank for the general public as well as for individual patients.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.1
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• pp.75-81
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• 1999

The beneficial effect of glucose and phosphate ions in culture medium on the development of human embryos in vitro has not been fully elucidated. The purpose of this study was to evaluate the influence of fertilization and culture of embryos in glucose/phosphate-free m-TALP medium on pregnancy rates in IVF-ET program. The patients in 244 IVF-ET cycles received GnRH agonist + HMG regimens. A does of 10,000 IU HCG was administered when two or more dominent follicles reached 18mm in diameter. Thirty-six hours after HCG, oocytes were recovered transvaginally using ultrasound guidance. Aspirated oocytes were matured for 4 to 6 h in TCM-199 supplemented with 10% follicular fluid (FF). Insemination was carried out with 50,000 motile spermatozoa in TCM-199 + 10% FF or m-TALP + 5% FF + 5% fetal cord serum (FCS) according to experimental design. After 6 h, oocytes were washed 3 to 4 times and cultured in each fresh medium. After 20 h, oocytes were freed from cumulus/corona cells and examined for the presence of pronuclei. Fertilized oocytes were transferred into each co-culture drops and cultured for further incubation. On day 3, embryo transfer was performed with grade 1 and 2 embryos. Monolayers for co-culture of embryos were prepared by plating $1{\times}10^5$ cumulus cells/ml in 10ul drop of TCM-199 + 10% FF or m-TALP + 5% FF + 5% FCS media 24 h prior to the onset of co-culture. Development to 4 to 16 cell stage was observed at 70x magnification following two days of incubation. Pregnancy was confirmed by detecting increasing serum ${\beta}$-hCG concentrations for 11 days following embryo transfer. Data were analyzed by ${\chi}^2$-test. Oocytes from 244 IVF-ET cycles were randomized. The number of cycles and mean age of patients were 97 and 147, 31.3 yrs and 31.2 yrs for TCM-199 (control) and m-TALP groups, respectively. The mean number of retrieved oocytes/cycle, fertilization rates, number of embryos transferred/ET and pregnancy rates were 11.1 and 10.3, 65.1% and 67.3%, 4.1 and 4.7, 28.9% and 43.8% for TCM-199 and m-TALP groups, respectively. Differences in the pregnancy rates were found between control and m-TALP groups (p<0.05). The pregnancy rate of patients divided according to maternal age groups of ${\leq}30$, 31-35, $36{\leq}$ were 44.4% and 49.0%, 26.1% and 41.3%, 29.2% and 41.2% for control and m-TALP groups, respectively. These data indicate that culture of human embryos in glucose/phosphate-free m-TALP medium improves pregnancy rates.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.2
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• pp.165-176
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• 1993

These studies were carried out to investigate the optimal freezing protocol for 2 cell mouse embryos and to find the probability of quality control with 2-cell embryos frozen. The embryos showed the best survival by the protocol composed of a freezing solution with the cryoprotectants(1.5M propanediol + 0.1M sucrose), and a 2-steop thawing method(room temperature, 20 sec-37$^{\circ}C$, 20 sec). The developmental ability of frozen-thaw 2-cell embryos did not differ from that of fresh 2-cell embryos in m-KRB medium with 0.4% bovine serum albumin. But development of frozen-thaw embryos was depended on the supplements of the medium. In the albumin-free medium, the developmental rate(rate of blastocysts) was significantly reduced, compared with that in the medium with 0.4% BSA. Also, when frozen-thaw embryos were cultured in the meduim with human fetal cord serum(HCS), the developmental rate of frozen-thaw embryos was sligtly reduced, compared with that of fresh 2-cell embryos. Finally, frozen-thaw 2-cell mouse embryos were more sensitive to the toxic agent of disposable-plastic syringe. Therefore, toxicity of medium could be effectively detected by frozen-thaw 2-cell mouse embryos.

• 대한생식의학회:학술대회논문집
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• 2001.03a
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• pp.221-228
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• 2001

• Clinical and Experimental Reproductive Medicine
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• v.32 no.1
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• pp.47-54
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• 2005

Objective: Evaluation of embryos using early cleavage to 2-cell stage has been proposed, but a critical time-point for selecting embryos is unclear. The aim of the present study is to provide a guideline including critical time-point in the selection of early cleaving embryo for the reduction of multiple pregnancies as well as the increase of pregnancy rate in human IVF. Methods: This prospective study was performed in 116 cycles from 85 patients who underwent conventional IVF or ICSI at the infertility clinic of Good Moonhwa Hospital from January 2002 to December 2003. Early cleavage (EC) of embryos to 2-cell stage was assessed at 25 h and 27 h postinsemination/microinjection. Embryos that had early cleaved at each time point were designated as EC-1 and EC-2, respectively, while others were designated as non-early cleavage (NEC). Results: At least one early cleavage embryo was observed in 54 (46.6%) for the EC-1 and 84 (72.4%) for the EC-2 of the 116 cycles assessed. Clinical pregnancy rates (PR) were significantly higher in the EC-1 group (66.7%) compared to the EC-2 group (53.6%) or the NEC group (31.2%) (p<0.05). Significant improvement of the pregnancy rate was found when at least two or more embryos were early cleaved at 25 h postinsemination or when the proportion of early cleavage embryo at 25 h postinsemination was higher than 20% (p<0.05). Conclusion: The critical time-point for the selection of early cleavage embryos with high implantation potential is more effective in 25 h postinsemination/microinjection compared to 27 h. The proportion as well as number of early cleavage embryos is also an important factor for the prediction of pregnancy outcome and the chance of multiple pregnancies. These results demonstrated that the evaluation of early cleavage embryos to 2-cell stage is an easy, simple, and objective method for the selection of good quality embryos suitable for embryo transfer.

• Korean Journal of Animal Reproduction
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• v.18 no.2
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• pp.105-111
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• 1994

The effects of human or mouse leukemia inhibitory factor(hLIF or mLIF) were examined as a means of increasing the development of in vitro matured(IVM) and in vitro fertilized (IVF) oocytes into morulae or blastocysts. Cell numbers of blastocysts were also counted using Hochest dye staining. Two-to 8-cell embryos derived from bovine IVM/IVF oocytes were cultured 5 to 6 days in CRI aa with or without mLIF or hLIF. All culture media were contained 3mg/ml bovine serum albumin. In experiment 1, the proportion of embryos developed to morulae and blastocysts in CRI aa containing 5,000U/ml mLIF(37.8%) was slightly higher than those of CRIaa containing 1,000U/ml mLIF(34.6%) and 0 U/ml mLIF(27.4%; P>0.05). In experiment 2, 0, 1,000 and 5,000U/ml of hLIF added to CR1aa media yielded 27.6%, 43.0% and 35.5% morulae and blastocysts, respectively(p>0.05). These were no significant increases in cell number among treatments(p>0.05). These results were indicating that mLIF or hLF can increase the proportion of embryos that develop into morulae and blastocysts without and increase in the cell number.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.4
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• pp.225-238
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• 2022

The ultimate goal of human assisted reproductive technology is to achieve a healthy pregnancy and birth, ideally from the selection and transfer of a single competent embryo. Recently, techniques for efficiently evaluating the state and quality of preimplantation embryos using time-lapse imaging systems have been applied. Artificial intelligence programs based on deep learning technology and big data analysis of time-lapse monitoring system during in vitro culture of preimplantation embryos have also been rapidly developed. In addition, several molecular markers of the secretome have been successfully analyzed in spent embryo culture media, which could easily be obtained during in vitro embryo culture. It is also possible to analyze small amounts of cell-free nucleic acids, mitochondrial nucleic acids, miRNA, and long non-coding RNA derived from embryos using real-time polymerase chain reaction (PCR) or digital PCR, as well as next-generation sequencing. Various efforts are being made to use non-invasive evaluation of embryo quality (NiEEQ) to select the embryo with the best developmental competence. However, each NiEEQ method has some limitations that should be evaluated case by case. Therefore, an integrated analysis strategy fusing several NiEEQ methods should be urgently developed and confirmed by proper clinical trials.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.1
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• pp.14-21
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• 2015

Objective: It has previously been suggested that embryos developing from intracytoplasmic sperm-injected (ICSI) zygotes with three pronuclei (3PN) are endowed with a mechanism for self-correction of triploidy to diploidy. 3PN are also observed in zygotes after conventional in vitro fertilization (IVF). The parental origin, however, differs between the two fertilization methods. Whereas the vast majority of 3PN IVF zygotes are of dispermic origin and thus more likely to have two centrioles, the 3PN ICSI zygotes are digynic in origin and therefore, more likely to have one centriole. In the present study, we examine whether the parental origin of 3PN embryos correlates with the karyotype. Methods: The karyotype of each nucleus was estimated using four sequential fluorescence in situ hybridizations-each with two probes-resulting in quantitative information of 8 different chromosomes. The karyotypes were then compared and correlated to the parental origin. Results: 3PN ICSI embryos displayed a significantly larger and more coordinated reduction from the assumed initial 3 sets of chromosomes than 3PN IVF embryos. Conclusion: The differences in the parental origin-and hence the number of centrioles-between the 3PN IVF and the 3PN ICSI zygotes are likely to be the cause of the differences in karyotypes.