• Clinical and Experimental Reproductive Medicine
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• v.21 no.3
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• pp.325-330
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• 1994

The study has been carried out in order to evaluate the effects of embryonic stage, and cryopreservation method on the rates of viability and development of the cryopreserved mouse early embryos. The results were as following:In the treatment steps of cryoprotectant, for the fertilized oocyte with pronucleus(PN), 2-step was better than the others. And for the other embryos, 4-step was better than 2- or 3-step. In respect to the embryonic stage, as the embryos developed from fertilized oocytes to 8-cell embryos, the rates of viability and development were increased higher. Therefore, 8-cell embryo was better stage than the others. In respect to the kind of cryoprotectants, PROH was better than DMSO for the fertilized oocyte, as a cryoprotectant. DMSO, for the 2-cell embryos and PROH and DMSO for the 4- and 8-cell embryos were suitable for cryopreservation.

• Journal of Embryo Transfer
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• v.27 no.2
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• pp.121-126
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• 2012

The objective of this study was to examine the effect of in vitro culture media on embryonic development of in vitro-matured (IVM) oocytes after parthenogenetic activation (PA) in pigs. Immature pig oocytes were matured in TCM-199 supplemented with porcine follicular fluid, cysteine, pyruvate, EGF, insulin, and hormones for the first 22 h and then further cultured in hormone-free medium for an additional 22~26 h. IVM oocytes were activated by electric pulses and cultured in porcine zygote medium-3 (PZM-3) and North Carolina State University-23 supplemented with essential and non-essential amino acids (NCSU-23aa). These media were further modified by supplementing 2.77 mM myo-inositol, 0.34 mM trisodium citrate, and $10{\mu}M$ ${\beta}$-mercaptoethanol (designated as mPZM-3 and mNCSU-23aa, respectively). Culture of PA embryos in mPZM-3 significantly increased development to the blastocyst stage than culture in NCSU-23aa (36.2% vs. 24.8%, p<0.05). Modified PZM-3 showed a significantly higher blastocyst formation than NCSU-23aa in both groups of embryos that were activated at 44 h and 48 h of IVM (51.0% vs. 35.5% and 49.0% vs. 34.2% in oocytes activated at 44 h and 48 h of IVM, respectively). Irrespective of the follicle diameter where oocytes were collected, embryonic development to the blastocyst stage was increased (p<0.05) by the culture in mPZM-3 compared to culture in NCSU-23aa (25.9% vs. 34.2% and 32.9% vs. 44.8% in embryos derived from small and medium size follicles, respectively). Our results demonstrated that culture media had significant effect on preimplantation development PA embryos and that mPZM-3 was superior to mNCSU-23 in supporting development to the blastocyst stage in pigs. This beneficial effect of mPZM-3 on embryonic development was not impaired by other factors such as time of oocyte activation and origin of immature oocytes (small and medium size follicles).

• Clinical and Experimental Reproductive Medicine
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• v.24 no.1
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• pp.35-42
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• 1997

The present study was designed to define the role of prostaglandin in the development and hatching of mouse embryo. The effects of indomethacin, an inhibitor of prostaglandin synthesis, on the development and hatching of morula and blastocyst were examined. In early morula stage, embryos were degenerated significantly at 100 ${\mu}M$ and 200 ${\mu}M$ indomethacin. However, the viability of embryos was not influenced by concentration in any other embryonic stages. In all embryonic stages, the hatching was suppressed with concentration dependent manner, but expansion was not suppressed. Particularly, in 84h embryos post hCG injection, the hatching was suppressed significantly compared with post hCG 72h or 96h embryos. When embryos were treated with 100 ${\mu}M$ indomethacin for a specific time (12h) in according to the development stage, the hatching was suppressed all groups. These suppressional effect was decreased as embryonic development stage was progressed. However, the expansion was not affected in all treatment group. This study suggests that hatching-related metabolic substances are synthesized from morula stage and intraembryonic signaling mediated prostaglandin was important for development and hatching of mouse embryo.

• Health Policy and Management
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• v.14 no.3
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• pp.97-121
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• 2004

Recently, human embryonic stem cell research raises exciting public expectation on medical possibilities as well as ethical debate. Embryo management has become an integral part of the management of infertility treatment, researches on embryo and human embryonic stem cells and so on. Britain has permitted the research on stem cells derived from human embryo which made the first nation to allow the cloning of human embryo for the stem cell research. However, new technologies such as the assisted reproductive technologies and human embryonic stem cell research continue to pose an increasing source of ethical dilemmas for physician, scientists, legislators, religious authorities and the general publics to deal with. None the less, the United Kingdom has adopted the most liberal policies regarding human embryo and human embryonic stem cell research. The implication of the British embryo management system are as follows: 1) the development of reproductive technologies and new stem cell research technologies continue to pose legal and ethical debates, since those involve several parties; 2) the UK has taken the legal and institutional approaches to cope with those serious issues; 3) the UK adopted most liberal policies regarding embryonic and human embryonic stem cell researches; 4) the British HFE Act is consistent with the existing Acts related to human embryo management and researches; 5) through amending the HFE Act to accomodate the changes of technologies, the UK try to minimize the legal and ethical burden on undertaking research regarding embryo. The debates about the researches on human embryo and human embryonic stem cells is likely to continue in the Korean society. Because of the controversy and competing ethical values, as well as the evolving technologies, so far no consensus exists in our society. It suggest that it is premature to bring closure by ruling out any particular approaches. Thus our society needs to make an efforts to find a basis which could resolve the societal controversies through enriching the societal conversation about the profound ethical issues regarding embryo management.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.6
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• pp.910-927
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• 2003

Transgenesis is a very powerful tool not only to help understanding the basics of life science but also to improve the efficiency of animal production. Since the first transgenic mouse was born in 1980, rapid development and wide application of this technique have been made in laboratory animals as well as in domestic animals. Although pronuclear injection is the most widely used method and nuclear transfer using somatic cells broadens the choice of making transgenic domestic animals, the demand for precise manipulation of the genome leads to the utilization of gene targeting. To make this technique possible, a pluripotent embryonic cell line such as embryonic stem (ES) cell is required to carry genetic mutation to further generations. However, ES cell, well established in mice, is not available in domestic animals even though many attempt to establish the cell line. An alternate source of pluripotent cells is embryonic germ (EG) cells derived from primordial germ cells (PGCs). To make gene targeting feasible in this cell line, a better culture system would help to minimize the unnecessary loss of cells in vitro. In this review, general methods to produce transgenic domestic animals will be mentioned. Also, it will focus on germ cell engineering and methods to improve the establishment of pluripotent embryonic cell lines in domestic animals.

• Plant Biotechnology Reports
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• v.3 no.4
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• pp.341-345
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• 2009

This study describes culture conditions for a plant regeneration system via a combined pathway of somatic embryogenesis and organogenesis in root explant cultures of the commercial rose cultivar 'Charming'. Root explants formed white calluses at a frequency of 30% after 6 weeks of culture on Schenk and Hildebrandt (SH) medium supplemented with $11mg\;1^{-1}$ 2,4-dichlorophenoxyacetic acid. After 6 weeks of transfer to SH medium without growth regulators, initial white calluses gave rise to globular somatic embryos at a frequency of 2.8%, which were subsequently dedifferentiated to embryonic tissues. Somatic embryos or embryonic tissues initially derived from root explants did not undergo development beyond cotyledonary stage. To produce adventitious shoots, embryonic tissues were sliced and cultured on SH medium with $0.5mg\;1^{-1}$ 6-benzyladenine. After 4 weeks of culture, 28% of embryonic tissue explants formed adventitious shoots. Regenerated shoots were rooted on half strength SH medium with $0.1mg\;1^{-1}$ ${\alpha}-naphthalaneacetic$ acid and subsequently grown to maturity. Root-derived embryonic tissues were proliferated by subculture, while retaining the capacity for shoot production for a few years.

• Korean Journal of Veterinary Research
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• v.59 no.4
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• pp.201-205
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• 2019

This study presents neurogenesis and neuronal migration patterns of gamma-aminobutyric acid-ergic (GABAergic) neurons during mesencephalic development of mouse. After neurons from embryonic day (E) 10-16 were labelled by a single injection of 5-bromo-2'-deoxyuridine (BrdU), immunohistochemistry was performed. Neurogenesis were mainly generated in the mesencephalic region at E10 to E13. After E14, BrdU positive cells were observed only in the dorsal mesencephalon. GABAergic neurons were mainly originated in the ventrolateral region of the mesencephalon at the early embryonic stage, especially at E11 to E13. E10-labeled cells showed positive for GABAergic neuron in the basal plate of the mesencephalon at E13. At E15, GABAergic neurons were observed in the entire basal plate and some regions of the ventral and dorsal mesencephalon. They were present in the whole basal plate, the ventral and dorsal mesencephalon of E17, spreading more outward of the mesencephalon at P0. Our study demonstrates that major neurogenesis of GABAergic neurons occurs at E11 to E13. However, neuronal migration continues until neonatal period during mesencephalic development.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.3
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• pp.253-258
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• 1995

Microtubules and microfilaments are major cytoskeletal components in mammalian ova that provide the framework for chromosomal movement and cellular division. Extensive changes of cytoskeletal organization occur during maturation and fertilization. The changes in cytoskeletons are essential for the normal meiotic maturation and for the formation of the biparental diploid genome of the embryo, and thus are repeated at each cell cycle during embryonic development. Disturbance of the cytoskeletal organization could result in abnormal gamete development and early embryonic death.

• BMB Reports
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• v.48 no.12
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• pp.668-676
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• 2015

Pluripotent stem cells only exist in a narrow window during early embryonic development, whereas multipotent stem cells are abundant throughout embryonic development and are retainedin various adult tissues and organs. While pluripotent stem cell lines have been established from several species, including mouse, rat, and human, it is still challenging to establish stable multipotent stem cell lines from embryonic or adult tissues. Based on current knowledge, we anticipate that by manipulating extrinsic and intrinsic signaling pathways, most if not all types of stem cells can be maintained in a long-term culture. In this article, we summarize current culture conditions established for the long-term maintenance of authentic pluripotent and multipotent stem cells and the signaling pathways involved. We also discuss the general principles of stem cell maintenance and propose several strategies on the establishment of novel stem cell lines through manipulation of signaling pathways.

• Animal cells and systems
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• v.13 no.2
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• pp.235-245
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• 2009

Embryonic stem (ES) cells have a capability to generate all types of cells. However, the mechanism by which ES cells differentiate into specific cell is still unclear. Using microarray technology, the differentiation process in mouse embryonic stem cells was characterized by temporal gene expression changes of mouse ES cells during differentiation in a monolayer culture. A large number of genes were differentially regulated from 1 day to 14 days, and less number of genes were differentially expressed from 14 days to 28 days. The number of up-regulated genes was linearly increased throughout the 28 days of in vitro differentiation, while the number of down-regulated genes reached the plateau from 14 days to 28 days. Most differentially expressed genes were functionally classified into transcriptional regulation, development, extra cellular matrix (ECM),cytoskeleton organization, cytokines, receptors, RNA processing, DNA replication, chromatin assembly, proliferation and apoptosis related genes. While genes encoding ECM proteins were up-regulated, most of the genes related to proliferation, chromatin assembly, DNA replication, RNA processing, and cytoskeleton organization were down-regulated at 14 days. Genes known to be associated with embryo development or transcriptional regulation were differentially expressed mostly after 14 days of differentiation. These results indicate that the altered expression of ECM genes constitute an early event during the spontaneous differentiation, followed by the inhibition of proliferation and lineage specification. Our study might identify useful time-points for applying selective treatments for directed differentiation of mouse ES cells.