• Journal of Embryo Transfer
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• v.3 no.1
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• pp.43-47
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• 1988

공란우 89두와 수라우 94두를 사용하여 호르몬 투여에 대한 난소반응, glycerol의 평형과 제거방법에 따른 융해란자의 형태적 정상성과 동결 융해란의 이식후 임신율과 쌍태유기율을 조사하였다. 1. 호르몬처리에 대한 난소반응 :1) 과배란 처리후 배란된 난자수는 A.B.C군에서 각각 8.3, 7.8, 9.5개로서 C군이 전체 평균의 8.3개보다 증가되었다. 2) 난자의 회수율은 42.1%, 두당회수된 난자수는 3.5개였으며, 회수란자중 정상발육한 상실배와 배반포기의 난자는 63.3%, 36.7%(114/311)가 형태적 이상란자로 확인되었다. 2. 수정란의 동결 융해후 형태적 정상성 :1) 동결융해후 회수된 난자중 정상 난자의 비율은 60.4%였으며, 배반포(62.3%)가 상실배(58.3) 보다 우수하였다. 2) 1단계 glycerol의 제거시에는 동결전 glycerol의 평형을 3단계로 실시한 군(C.G)이 1단계 평형군 (A.E)보다 우수하였다. 3. 동결융해란의 이식후 쌍태유기 :1) 수정란의 이식후 임신율은 단태(대조)구에서 30.0%, 쌍태유기군인 A(AI+단태), B(편각쌍태) 및 C(쌍각쌍태)구에서 각각 55.6, 44.4, 37.5%로서 대조구보다 증가되었다. 2) 쌍태유기에 공용된 26두의 수란우에 착상된 수정란수는 17(65.4%)개로서 딘태구(30.0%) 보다 배가되었다.

• Journal of Embryo Transfer
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• v.10 no.3
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• pp.237-242
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• 1995

Porcine follicular oocytes matured in culture were inseminated with frozen-thawed spermatozoa. When the oocytes were inseminated in the medium with oviductal epithelial cell monolayer, the penetration rates higher in those with (4.1, 31.7, 45.1, 54.5 and 69.4%) than without cells (0, 17.1, 34.8, 45.2 and 58.9%) at 4, 8, 12, 16 and 20 h after insemination. The proportions of polyspermy in penetrated oocytes in medium with or without cells increased with time of examine. In another experiment, the penetration rate was higher without (57.6%) than with (19.6~24.1%) preincubation of spermatozoa for 1~4 h in medium. However, when the oocytes were inseminated with spermatozoa preincubated for 1~2 h, the penetration rates significantly higher (P<0.05) in those with (65.6 and 55.9% for 1 and 2 h) than without (24.1 and 20.6% for 1 and 2 h) oviductal epithelial cell monolayer. On the other hand, the proportions of polyspermy decreased with time of spermatozoa preincubation. These results indicate the significant advantages of the spermatozoa preincubation with oviductal epithelial cell monolayer for 1 and 2 h to maintain penetration potential during in vitro fertilization in the porcine.

• 대한생식의학회:학술대회논문집
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• 2007.11a
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• pp.104.1-104.1
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• 2007

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.134-134
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• 2003

Bovine embryos produced by in vitro maturation, feretilization and development was examined for presevation and transfer. The fertilization medium used BO medium with 5 mM/$m\ell$ caffeine and 10$\mu\textrm{g}$/$m\ell$ heparin and adjusted to a pH of 7.2 to 7.4. The final concentration of spermatozoa was adjusted to 1$\times$$10^{6}$ cells/$m\ell$ motile sperm during fertilization in vitro. At 8~10 hrs after insemination, the oocytes were transferred into CR1aa medium and cultured for 7 days. Embryos were preserved by vitrification method for transfer. When the embryos of early, blastocyst and expanded blastocyst stages were frozen-thawed, the proportions of embryos with normal morphology 83.6, 88.1 and 85.2%. (중략)

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.523-527
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• 1991

The effects of ethylene glycol, DMSO and glycerol as cryoprotectants and the effect of concentrations(0, 0.25, 0.5 and 1.0M) of sucrose in the diluent on the viability of the aggregated morulae frozen rapidly in liquid nitrogen$(LN_2)$ vapour were examined. The morulae were produced by aggregation of ICR and CBA mice embryos at 8-cell stage. Before freezing the embryos were equilibrated in 1.5M cryoprotectants+0.25M sucrose in oae-step or in 3.0M cryoprotectants+0.25M sucrose in two-steps. The embryos were pipetted into the freezing medium fraction of 0.25ml plastic straws. The straws were frozeu by directly transfer into $LN_2$ vapour(about lcm above $LN_2$) for 2 minutes, and then plunged into $LN_2$. After thawing the cryoprotectants were diluted with 0, 0.25, 0.5 or 1.0M sucrose solution. The post-thawed in vitro viability of the aggregated embryos was significantly dependent on the type and concentration of cryoprotectants in the freezing medium and also on the concentration of sucrose in the diluent. When the aggregated embryos were equilibrated in 1.5M cryoprotectants +0.25M sucrose in one-step and diluted with 0.5M sucrose after thawing, the survival rate of the embryo5 was significantly(p<0.05) higher in DMSO(62.5%) or ethylene glycol(52.2%) than in glycerol(33.3 %). In the case that the concentration of the cryoprotectants was raised to 3.0M in two-steps, thc higher survival rate of the embryos was obtained in ethylene glycol or glycerol than in DMSO followed by diluting them with 0.5 or 1.0M sucrose after thawing(p<0.01).

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.179-186
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• 2003

Human embryonic stem (hES) cell lines have been derived from human blastocysts and are expected to have far-reaching applications in regenerative medicine. The objective of this study is to improve freezing method with less cryo-injuries and best survival rates in hES cells by comparing various vitrification conditions. For the vitrifications, ES cells are exposed to the 4 different cryoprotectants, ethylene glycol (EG), 1,2-propanediol (PROH), EG with dime-thylsulfoxide (DMSO) and EG with PROH. We compared to types of vehicles, such as open pulled straw (OPS) or electron microscopic cooper grids (EM grids). Thawed hES cells were dipped into sequentially holding media with 0.2 M sucrose for 1 min, 0.1 M sucrose for 5 min and holding media for 5 min twice and plated onto a fresh feeder layer. Survival rates of vitrified hES cells were assessed by counting of undifferentiated colonies. It shows high survival rates of hES cells frozen with EG and DMSO (60.8％), or EG and PROH(65.8％) on EM grids better than those of OPS, compared to those frozen with EG alone (2.4％) or PROH alone (0％) alone. The hES cells vitrified with EM grid showed relatively constant colony forming efficiency and survival rates, compared to those of unverified hES cells. The vitrified hES cells retained the normal morphology, alkaline phosphates activity, and the expression of SSEA-3 and 4. Through RT-PCR analysis showed Oct-4 gene expression was down-regulated and embryonic germ layer markers were up-regulated in the vitrified hES cells during spontaneous differentiation. These results show that vitrification method by using EM grid supplemented with EG and PROH in hES cells may be most efficient at present to minimize cyto-toxicity and cellular damage derived by ice crystal formation and furthermore may be employed for clinical application.

• Journal of Embryo Transfer
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• v.19 no.1
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• pp.1-10
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• 2004

These studies were carried out to improve the reproductive efficiency through embryos transfer of Hanwoo IVM/IVF embryos. Following routine IVM/IVF procedure, oocytes and zygotes were cultured far 40 to 44 h in CRlaa medium with BSA. Then 2 to 8-cell embryos were removed the cumulus cell and were cultured in CRlaa medium containing 10% fatal bovine serum and 2.5 mM taurine in 5% $O_2$ and 5% $CO_2$ at 38.5$^{\circ}C$. The fresh embryos of the morulae and blastocysts cultured for 6 to 9 days in vitro or the frozen-thawed embryos were transferred into recipients. The pregnancy rates of the blastocyst produced for 6, 7, 8, and 9 days in vitro culture were 59.4, 68.2, 66.0 and 100%, respectively. In the developmental stage, pregnacy rates of early blastocysts (61.1%), blastocysts(64.7%) and expanded blastocysts(69.5%) were higher than that of morulae stage(20.0%). The pregnancy rates according to the corpus luteum grades of A, B and C in recipients were 73.6, 62.9 and 50.0%, respectively. Effects of donor-recipients synchrony of after day 2, 1 and 0, before day 1 and 2 on the pregnancy rates were 35.7, 65.5, 72.6, 67.9 and 60.0%, respectively. Pregnancy rates of the body condition score of recipients $\leq$2(71.3%) were higher than those of $\geq$3.0 score(40.0%). The pregnancy rates according to the parity of recipients when embryo was transferred to cow(70.6%) was higher than in heifer(59.1%). The pregnancy rates according to hormone treatment before embryo transfer were 69.9% in hCG + GnRH administration group and 63.0% in control group. Fresh and frozen-thawed embryos on the pregnancy rates were 70.6 and 36.4%, respectively. Pregnancy rates in single and AI+single was 90.0% and 64.8%. Pregnancy rates in twin induction was better than in single. These results indicate that pregnancy rates after transfer were affected on the embryo ages, donor-recipient synchrony, body condition score of recipients, corpus luteum status, parity and hormone treatment to recipients.

• Journal of Embryo Transfer
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• v.32 no.1
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• pp.1-8
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• 2017

Cryopreservation of germ cells from genetically proven animals could be a source of restoration tools from the risk of extinction or disappearance of wanted characteristics. Using frozen semen, the genetic gains of Korean native cattle have been increased greatly for 70 years. The preservation of genetic resources as a form of frozen semen straw has limited availability due to the numbers. To circumvent this weakness of frozen semen, we tested two re-freezing methods with different initial thawing temperatures using frozen Korean proven semen and rare breed semen from albino, black and chikso breeders. It has been known that human sperm could resist to cryo-damages by repeated freeze-thaw cycles, but not for Korean proven bulls number (KPN) or for rare breeds. Total 7 frozen semem from brindled(2), black(1), Korean Albino(2) and KPN(1) bulls were used for our research. After thawing straws under $5^{\circ}C/2min$ or $37^{\circ}C/40sec$ with low temperature water bath and thermo jug, spermatozoa were re-diluted with triladyl diluents after first thawing and re-frozen. Sperm motilities were compared between animals and treated groups after re-thawing. Mean values of motility and viability of refrozen/thawed sperm for expansion of the number of straws were significantly higher in $5^{\circ}C$ than in $37^{\circ}C$ (P < 0.05). However, the activity of viable sperm thawed at $5^{\circ}C$ was significantly decreased before refreezing. It is estimated that re-freezing of frozen semen from rare Korean native cattle is possible with resistant properties of survived spermatozoa.

• Journal of Embryo Transfer
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• v.13 no.1
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• pp.1-9
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• 1998

In order to improve the cryopreservation by vitrification or slow freezing of nuclear transplant rabbit embryos, the effects of factors affecting embryo cryopreservation such as cryoprotectants, equilibration, cooling rate and post-thaw dilution on post-thaw survial and development were determined using intact embryos of morular stage. And the post-thaw development of nuclear transplanted embryos cryopreserved under the optimal conditions examined was compared between vitrification and slow freezing. The cryoprotectant solution used was ethyleneglycol-ficoll-sucrose (EFS) or ethyleneglycol-poly-vinylpyrrolidone-galactose- I (EPG- I ) for vitrification, and EPG- II for slow freezing. To examine the viability of frozen-thawed embryos, the nuclear transplanted embryos were co-cultured in TCM-199 plus 10% FBS with bovine oviduct epithelial cells(BOEC) for 24 hrs and the intact morulae were co-cultured with BOEC for 5 days and 3 days to hatching blastocyst stage in 39 ˚C 5% $CO_2$ incubator. The results obtained were as follows: Following vitrification with EFS, the post-thaw development of rabbit morulae to hatching blastocyst was significantly(P<0.05) higher in compacted stage(82.4%) than in early morular stage(60.0%). The post-thaw development of compacted morulae to hatching blastocyst was similarly high in vitrification with EFS(82.4%), EPG- I (85.0%) and in slow freezing with EPG- II (83.3%). Following vitrification with EPG- I, the post-thaw development of intact rabbit morulae to hatching blastocyst was similar as 78.0% and 85.0% in 1-step and 2-step post-thaw dilution, respectively. The post-thaw development of nuclear transplanted rabbit embryos of compacted morulae stage to hatching blastocyst was similarly 43.6% and 40.0% in vitrification with EPG- Iand slow freezing with EPG- II, respectively. These results indicated that the rabbit nuclear transplant and intact embryos of morulae stage could be well cryopreserved with either vitrification or slow freezing procedure.

• Journal of Embryo Transfer
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• v.10 no.1
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• pp.53-63
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• 1995

The effects of different protein sources (serum vs bovine serum albumin), growth factors (EGF and PDGF) and co-culture with various type of somatic cel1s (BOEC, MEF and BRL) on the in vitro development of in vitro matured / in vitro fertilized bovine oocytes were examined, and the viability of frozen/thawed embryos derived from IVM /IVF was examined. Cell numbers of blastocysts were also counted. In Experiment 1, CR$_1$aa with serum was superior to CR$_1$aa with BSA in producing morulae plus blastocysts from IVM /IVF oocytes(24.4% vs 30.4%, p>0.05). In Experiment 2, more morulae plus blastocysts(42.3%) were produced in CR$_1$aa containing long /ml EGF than in the control CR$_1$aa(33.3%). In Experiment 3, 2- to 8-cell embryos derived from IVM /IVF oocytes were randomly allotted to one of 4 culture groups : a) CR$_1$aa ; b) CR$_1$aa + ing /ml PDGF ; CR$_1$aa + Sng /ml PDGF ; CR$_1$aa + lOng /ml PDGF ; culture resulted in 21.3, 51.2, 41.4 and 45.9%(p<0.05), respectively, developing into morulae and blastocysts. In Experiment 4, 0 and Sng /ml PDGF added to CR$_1$aa coculture with BRL or BOEC yielded 47.5, 42.5, 33.8 and 41.6% morulae and blastocysts, respectively. In Experiment 5, the proportion of embryos into morulae and blastocysts was highest in CR$_1$aa with MEF coculture group(50.9%) compared to any other group(CR$_1$aa, 22.3%; CR$_1$aa+BRL, 32.9%; CR$_1$aa+BOEC, 33.8%, p>0.05). In Experiment 6, survival rate of blastocysts produced by in vitro fertilization when cryoprotectant was removed in 0.7M glycerol+0.7M sucrose and 0.7M sucrose solution for 10 min. after thawing at 2$0^{\circ}C$ (Exp. H, 58.8%) was slightly higher than when cryoprotectant was removed 10%, 6.7% and 3.3% glycerol for 10 min. after thawing at 37$^{\circ}C$ (Exp. I, 54.3%). These study indicate that growth factors and somatic cell co-culture can increase the proportion of embryos that develop into morulae and blastocysts without an increase in the cell number and frozen /thawed method employed this experiment was not different.