• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.157-157
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• 2003

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2005.10a
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• pp.44-45
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• 2005

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2003.10a
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• pp.66-66
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• 2003

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2006.10a
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• pp.88-88
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• 2006

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2004.10a
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• pp.69-69
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• 2004

• Journal of Embryo Transfer
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• v.10 no.3
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• pp.209-217
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• 1995

The present study was carried out to develop a cloning technology of mouse embryos by nuclear transplantation with electrofusion and to produce cloned offsprings by transfer of reconstituted embryos. A single nucleus from two- and eight-cell embryos was transplanted into the enucleated two-cell embryos by rnicromanipulation. The fusion of nucleus with recipient cytoplasm and the subsequent development of reconstituted embryos in vitro as well as in vivo to term were examined to determine the optimal electrofusion parameters for nuclear transplantation in mouse embryos. The successful enucleation of donor embryos was 84.9 and 83.3% in two- and eight-cell stage, respectively, and the successful injection of nucleus from two- and eight-cell donor embryos into the perivitelline space of enucleated two-cell embryos were 85.1 and 84.7%, respectively. No significant differences were found in enucleation or injection rate between the cell stages of donor embryos. When the blastomeres of intact two-cell mouse embryos were electrofused in 0.3 M mannitol medium(100 $\mu$sec., 3 pulses), the fusion rate was similarly 93.2, 92.2 and 92.0% in 1.0, 1.5 and 2.0 kV /crn, respectively, but in vitro development to blastocyst of the fused two-cell embryos was significantly(P<0.05) lower in 2.0 kV/cm (63.4%) than in 1.0 kV/cm (91.7%) or 1.5 kV/cm (82.4%). The development in vitro to eight-cell stage of the reconstituted embryos with nucleus from two-cell stage(45.5%) was significantly(P<0.05) higher than that from eight-cell stage blastomeres (16.7%). The number of blastomeres of the intact embryos at blastocyst stage was 50i0.6 and 55$\pm$2.4 in in vitro and in vivo cultured mouse embryos, respectively, but significantly(P<0.05) decreased to 35$\pm$0.7 in nuclear transplanted blastocyst embryos. The conception rate of mice following embryo transfer was 32.1% in the reconstituted two-cell embryos using two-cell donor nuclei, which was comparable to the fresh two-cell embryos(40.6%). However, the rate of development in vivo to term following embryo transfer of the reconstituted two-cell embryos using two-cell donor nuclei (23.5%) was significantly(P<0.05) lower compared with the percentage of two-cell fresh embryos(31.5%).

• The Korean Journal of Zoology
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• v.39 no.4
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• pp.352-361
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• 1996

The c-myc proto-onco9ene, one of the immediately early genes, is involved in ceflular proliferation and differentiation, and its biologleal function is regulated hy dimerization with a heterodimeric partner, myn. In the present study, gene expression patterns of c-myc and myn during mouse preimplantation embryo development were examined using a semi-quantitative reverse transcription-poiymerase chain reaction (RT-PCR). Myn transcripts were rather constitutively expressed throughout embryonic stages with a slight increase only at biastocyst stage. in contrast, expression of c-myc transcripts wm developmental stage-'pedfic. The c-myc transcripts were detected at 1-cell stage, declined abruptly at 2-cell stage and then increased gradually at blastocyst stage. To examine the possible role of myn during preimpiantation mouse embryo development, two myn antisense oligonucleotides spanning the tail of zipper dognain (myn2; 20-mer) and the second helix domain (myn3; 20-mer) were microinjected into the fertilized 1-cellembryos. Microinjection of myn2 and myn3 resulted in developmental tion at morula/biastocyst transition stage, leading to the fiagentation of embryos. Talien together, these results suggest that c-myc and its heterodimeric partner, myn, are differentially expressed In a developmental stage-dependent manner, and myn may play an important role in mouse preimpiantation embryo development.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.2
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• pp.233-239
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• 1997

Embryos of most mammalian species grown in vitro would undergo developmental arrest at the approximate time of genomic activation. Stage-specific cell block and the resulting rapid loss of embryo viability in conventional culture media have limited the duration for which embryos may be cultured prior to transfer. As a result, embryos are usually transferred to the uterus at the 4-to 8-cell stage to avoid the loss of viability associated with long-term in vitro culture. Early transfer has led to asynchrony of the endometrium-trophectoderm interaction at the time of implantation and a resultant reduction in the rate of implantation. To overcome these problems, a variety of co-culture systems has been devised in which embryos can develop for a longer period prior to embryo transfer. Vero cells, derived from African green monkey kidney, share a common embryologic origin with cells from the genital tract. In addition, they are potentially safe to use, since they are highly controlled for viruses and other contaminants. Therefore, co-culture using Vero cells has been widely utilized to enhance embryo viability and development, although not without controversies. We thus designed a series of experiments to demonstrate whether Vero cells do indeed enhance mouse embryo development as well as to compare the efficacy of co-culturing mouse 1-cell embryos on Vero cell monolayer in both Ham's F-10 and human tubal fluid (HTF) culture media. 1-cell stage ICR mouse embryos were cultured either in the presence of Vero cells (Group A) or in conventional culture medium alone (Group B). In Ham's F-10 significantly more 3-to-8cell embryos developed in group A than group B (59.8 versus 10.0%; p<0.01). In contrast, there was no significant difference in embryonic development both group A and group B in HTF. However, significant differences were noted only in later embryonic stage (13 and 0%; p<0.05 of group A and B respectively, hatching or hatched). In Ham's F-10, we also could observe the beneficial effect of Vero cell on hatching process (70.7 and 42.1%; p<0.05 of group A and group B respectively).

• Korean Journal of Animal Reproduction
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• v.15 no.2
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• pp.103-107
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• 1991

This study was carried out to investigate the survival rate in vitro culture after frozen-thawed to used DMSO(dimethyl sulfoxide), glycerol and ethylene glycol of cryoprotective agents at the zona pellucida removed and encased into alien bisected embryo of the mouse early embryos. The results obtained from this study were as follows : 1. The survival rate of in vitro culture after frozen-thawed to used cryoprotective agents of three kinds at the zona pellucida removed bisected morula was 46.6%, 35.8% and 27.3%, total or mean were 36.6%, respectively. 2. The survival rate of in vitro culture after frozen-thawed to used cryoprotective agents of three kinds at the encased into alien bisected morula was 70.6%, 65.3% and 66.4%, total or mean were 67.4%, respectively. 3. The survival rate of in vitro culture after frozen-thawed to used cryoprotective agents of three kinds at the zona pellucida removed bisected blastocysts was 50.4%, 36.7% and 30.4%, total of mean were 39.2%, respectively. 4. The survival rate of in vitro culture after frozen-thawed to used cryoprotective agents of three kinds at the encased into alien bisected blastocysts was 71.1%, 66.7% and 63.9%, total or mean were 67.2%, respectively.

• Journal of Embryo Transfer
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• v.11 no.1
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• pp.27-33
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• 1996

The efficient cryopreservation of embryos requires optimal times of dehydration and rehydration This study was carried out to investigate the effect of various times of dehydration and rehydration The effects were evaluated through testing morphological normality and developmental ability of 1 cell mouse embryos which were ultrarapidly frozen and thawed. The 1 cell embryos were dehydrated for 1.5, 3, 5, and 10 minutes using mPBS-BSA containing 3.SM DMSO and 0.25M sucrose on cooling chamber or on ice. After ultrarapidly frozen and thawed, they were rehydrated for 0, 0.5 and 5 minutes with mPBS-BSA containing 0.25M sucrose at room temperature. The results obtained were as follows: The embryos that were rehydrated for 0.5 minutes showed higher normality than the embryos for 0 and 5 minutes did. The embryos that were dehydrated for 10 minutes showed higher normality than the embryos for 1.5, 3, and 5 minutes did. The developmental ability of normal thawed-embryos was high in 10 minute dehydration treatment compared to other treatments. However, it was not affected by cooling methods (on ice and on cooling chamber) for embryo dehydration.