• 한국가축번식학회지
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• 제8권2호
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• pp.116-121
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• 1984

These experiments were carried out to examine the effect of rapid thawing (500$^{\circ}C$/min) on the survival of 8-cell mouse embryos cooled slowly (0.5-1$^{\circ}C$/min) to precooling temperatures between -10 and 070$^{\circ}C$ before direct transfer ofembryos to -196$^{\circ}C$, and to compare the survival of embroys thawed slowly (20$^{\circ}C$/min) and rapidly (500$^{\circ}C$/min) after in vitro culture. In addition, the sensitivity of 8-cell mouse embroys to the rate of addition and removal of cryoprotectant at room temperauture, and the effect of developing stages on the survival of embryos frozen-thawed slowly were investigated. The results obtained were summarized as follows: 1. Embryos were survived in rapid thawing (500$^{\circ}C$/min) only when slow cooling was terminated at relatively high subzero teperaure (-20 to -60$^{\circ}C$). The highest survival rate(77.0%) in in vitro culture of embryos thawed rapidly was obtaeined after transfer to -196$^{\circ}C$ from -40$^{\circ}C$. 2. For the survival of embryos in slow thawing (20$^{\circ}C$/min.), slow cooling to lower subzero temperature (-50$^{\circ}C$ and below) was required before transfer of embryos to -196$^{\circ}C$. These results indicate that embryos transferred to -196$^{\circ}C$ from high subzero temprature contain much interacellular ice to damage them during slow warming but to permit survival of embryos after rapid warming. 3. The Survival rate (72.7%) of 8-cell mouse embryos after rapid addition and removal of cryoprotectant, DMSO at room temperature was similar to that (83.9%) after slow addition and removal of cryoprotectant at same temperature. 4. The survival rates of 1-, 2-, 4- and 8-cell embryos frozen-thawed slowly were 26.7, 76.4, 70.0 and 83.9%, respectively.

• 한국수정란이식학회지
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• 제21권3호
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• pp.255-262
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• 2006

본 연구는 Open Pulled Straw(OPS)방법에 의해 동결-융해한 돼지 수정란의 체외 생존 능력을 검토하기 위하여 수행되었다. 미성숙 난자의 체외 성숙을 위하여, 돼지 난소는 도축장에서 회수하였으며, 난구세포로 쌓여있는 난자는 직경 $2{\sim}6mm$의 난포로부터 난포액과 함께 흡입에 의하여 회수하였다. 회수된 미성숙 난자의 체외 성숙을 위하여 5 mM hypotaurine, 0.57 mM cysteine, 10% 난포액, 10 IU/ml PMSG 및 10 IU/ml hCG가 함유된 NCSU-23 배양액 내에서 $21{\sim}22$ 시간 배양 후, 호르몬 물질을 제거한 성숙 배양액 내에서 $21{\sim}22$ 시간 동안 추가 배양하였다. 한편 체외 수정을 위하여 동결-융해한 정액은 5.56 mM glucose, 0.33 mM na-pyruvate, 100 IU/ml penicillin, $100 {\mu}g/ml$ streptomycin 및 4 mg/ml BSA가 첨가된 D-PBS 액을 가지고 1,500 rpm에서 10분간 2회 원심분리를 실시하여 세척하였다. 체외 수정을 위한 배양액은 pH $7.2{\sim}7.4$에서 2 mM caffeine과 2 mg/ml BSA가 첨가된 mTBM 배양액을 이용하였다. 체외 수정시 정자의 최종 농도는 $2.5{\times}10^6cells/ml$로 조정하였다. 수정 8시간 후, 체외 발육을 위하여 5.0 mM hypo-taurine, 4 mg/ml BSA 및 10 ng/ml EGF가 첨가된 NCSU- 23액으로 옮겨 7일간 배양을 계속하였다. 그 후 배반포의 여러 단계에서 OPS 법에 의해 동결-보존하였다. 그 결과, 동결-융해 후 형태학적으로 정상적인 수정란의 비율은 초기 배반포(28.3%)보다는 확장 배반포(38.9%)단계에서 동결했을 때 유의적으로 높게 나타났다(p<0.05). 한편, 동결-융해 후 상해를 입은 수정란의 비율은 확장 배반포보다는 초기 배반포 단계에서 동결된 수정란에서 유의적으로 높은 성적을 보였다(p<0.05). 또 다른 실험에서, 수정란의 동결-융해 후 형태학적으로 정상인 수정란을 48시간 추가 배양했을 때, Hatching 된 수정란의 비율은 초기 배반포, 배반포 및 확장배반포기 단계에서 동결-융해한 수정란에서 각각 6.7, 20.0 및 33.3%로 발육 단계가 높을수록 동결-융해 후의 생존율도 높게 나타났다. 본 연구의 결과로부터, 돼지에서 수정란의 동결-융해 후 생존성의 향상을 위해서는 발육 단계가 높은 배반포기 단계에서의 동결이 요구되며 본 연구에서 이용된 OPS 동결 방법이 폭넓게 활용될 것으로 사료된다.

• 한국가축번식학회지
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• 제21권2호
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• pp.95-102
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• 1997

The studies on the carried out to investigate the effective concentration of cryoprotectant agents and sucrose by one-step straw method of bovine embryos. The follicular oocytes were cultured in TCM-199 medium containing 10 IU/ml PMSG(Sigma, USA), 10 IU/ml hCG(Sigma, USA), 1$\mu\textrm{g}$/ml $\beta$-estradiol(Sigma, USA) and 10% FCS for 24~48 hrs in incubator with 5% CO2 in air at 38.5$^{\circ}C$ and then matured oocytes were again cultured for 12~18 hrs with motile capacitated sperm by preincubation of heparin. The bovine embryos following dehydration by cryoprotective agents and various concentrations of sucrose were directly plunged into liquid nitrogen and thawed in 3$0^{\circ}C$ water. Survival and in vitro developmental rate was defined as devellpmental rate on in vitro culture or FDA-test. The results are smmarized as followes : 1. The high in vitro developmental rates of bovine frozen embryos after rapidly thawed in freezing medium was attained 2.0M glycerol, 2.0M DMSO, 1M or 2.0M propanediol. 2. The high in vitro developmental rates of bovine frozen embryos after rapidly thawed in freezing medium was obtained single cryoprotectant(6.7~17.4%) than mixed cryoprotectants(6.7~16.7%). 3. In vitro developmental rate of bovine embryos after rapid frozen-thawing in the freezing medium added 0.25M and 0.50M sucrose were higher cleavage rate than those of sucrose concentration of 0.75M and 1.00M. 4. The freezing methods on in vitro developemental rates of bovine embryos was attained slow freezing method(9.70~15.6%) higher than rapid freezing method(9.4~13.3%).

• 한국임상수의학회지
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• 제19권1호
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• pp.73-79
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• 2002

To investigate the usability of frozen canine embryos for embryo transfer in the dog, 19 donors, 3 recipients, and 6 male dogs were used for the experiment. Natural mating or artificial insemination was performed for breeding the bitches in natural estrus. Vaginal smear test along with progesterone titre test were performed to detect the appropriate mating time and the bitches were bred twice during 3-6days following LH surge. Embryo collection was done on 8, 9-11, 12-13 days after the second mating to collect morula and blastocyst. Embryos were frozen using a programmable freezer and preseued in LNE tank. Embryos were thawed in 37$^{\circ}C$ water for 15 seconds and transferred into each uterine horn within 30 minutes. Embryos were collected from 13 bitches of 19 donors(68.4%) and the collected embryos were from between 9 and 13 days after 2nd mating. Embryos were produced both by natural mating(60.0%, 9115) and AI with frozen semen(100.0%, 4/4). Embryos were collected from the donors weighed between 2.5 and 30 kg and their age was from 1.5 to 3 years. 52 embryos were collected from 13 donors and the mean number of embryos was four. The stage of embryos was from 2-cell to gastrula and morulae were colledted mostly from 10 to 11 days after 2nd mating. Embryos were collected evenly from each uterine horn and the rate of embryo collection for the number of corpus luteum was 83.9%. Embryos were transferred to 3 recipients(morula 8, blastocyst 1, gastrula 8), however, no offspring was produced.

• 한국수정란이식학회지
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• 제17권1호
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• pp.55-59
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• 2002

ICSI시 동결 융해한 부고환 정자의 이용 가능성을 알아보고자 난자의 배양시 체외성숙율과 활성화 처리를 한 난자와 동결 융해한 부고환 정자로 ICSI시 체외발생율을 조사하였으며, 결과를 요약하면 다음과 같다. 1. 난포란을 회수 후 24시간 배양하였을 때 배양 시간에 따른 GV, MI, M II로의 체외성숙율은 각각 7/60(11.7%), 5/60(8.3%), 48/60(80.0%)였고 30시간 배양 시간에 따른 GV, MI, M II로의 체외성숙율은 각각 3/60(5.0%), 4/60(6.7%), 53/60(88.3%)였고 퇴화란은 각각 2/60(3.3%)와 1/60(1.7%)였다. 2. 동결 융해한 부고환 정자를 이용하여 활성화 처리를 한 난자에 ICSI를 하였을 때 상실배와 배반포로의 체외발생율은 각각 12/46(26.1%), 22/46 (47.8%)로서 비활성화처리 난자군 5/39 (12.8%), 10/39(25.6%)에 비해 높은 체외발생율을 나타냈다. 3. 활성화 처리를 한 난자에 신선정자, 부고환 정자 및 동결 융해한 부고환 정자로 ICSI시 체외 발생율은 각각 24/45(53.3%), 15/40(37.50%), l1/43 (25.6%)로서 신선정자에 비해 동결 융해한 부고환 정자처리군은 체외발생율은 약간 낮았지만 이용 가능성이 있음을 확인하였다.

• 한국가축번식학회지
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• 제20권1호
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• pp.71-76
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• 1996

This experiment was carried out to investigate the developmental ability of bovine embryos matured and fertilized in vitro to the gastrulation stage. The bovine oocytes were collected from 2∼5mm follicles, matured for 20∼24hrs in 5% CO2 incubator and then fertilized with frozen-thawed semen. On day 9 after IVF and after freezing and thawing the hatching abilities of expanding blastocysts were examined. Cleavage rate and production rate to expanding blastocysts were 59.7%(955/1604) and 20.7%(333/1604), respectively. Hatching rate of day-9 expanding blastocysts was 54%(40/74), that after freezing and thawing was 56%(79/141). Also, developmental ability of hatched blastocysts to the primitive streak stage was 26%(6/23).

• Clinical and Experimental Reproductive Medicine
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• 제21권1호
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• pp.69-76
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• 1994

The survival and pregnancy rates were compared between non-frozen embryos and cryopreserved embryos at either pronucleate or 2-4 cell stages using the freezing and thawing techniques being identical in both groups were compared with fresh embryos. 496 embryos were frozen with 1, 2-propanediol and sucrose and 117 2-4 cell stages embryos had been thawed and 79.6 and 66.0% of them respectively were survival. Clinical pregnancy rate was 19.2% for embryos frozen at the pronucleate stage and 19.0% for embryos frozen at the 2-4 cell stages while the pregnancy rate of non-frozen embryos was 21.3%. There were no significant difference in the survival and pregnancy rates of embryos frozen at pronucleate and 2-4 cell stages. The current cumulative pregnancy rate per retrieval in all cycles with frozen zygotes is 35.4 %, consid~ erably higher than observed in single transfers of embryos without cryopreservation(21.3%); predicted pregnancy rate after transfer of all frozen embryos is 43.3 %. It is concluded that firstly, the survival and pregnancy rate of cryopreserved embryos at pronucleate or 2-4 cell stages are very similar to those from their fresh embryos and non-frozen embryos and secondly, cryopreservation substantially enhances pregnancy attainment from in vitro fertilization.

• 한국가축번식학회지
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• 제20권2호
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• pp.155-161
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• 1996

For a large sclase production of genetically identical or cloned animals, the effect of cryopreservation by vitrification on the post-thaw viability of nuclear transplant rabbit embryos were investigated. The embryos of 16-cell stage were collected from the mated does at 48 hours post-hCG injection, and they were synchronized to G1 phase of 32-cell stage were injected into enucleated recipient cytoplasms by micromanipulation. After culture until 20h post-hCG injection, the nuclear transplant oocytes were electrofused and activated by electrical stimulation. After in vitro culture for 48h, the nuclear transplant embryos developed to morula stage were cryoperserved with EFS solution by vitrification method. The forzen nuclear transplant embryos were thawed and cultured for 72h and the nuclear transplant of blastomeres under a fluorescence microscopy. The in vitro development to blastocyst of intact-fresh and intact-frozen 16-cell embryos was found to be 96.9 and 63.9%, respectively. The in vitro development to blastocyst of nuclear transplant and frozen-thawed nuclear transplant embryos was found to be 74.5 and 42.9%, respectively. Also, their mean blastomere numbers and mean cell cycles/day was 153 and 105, 145 and 1.34, respectively. From the above results it was concluded that the present cryopreservation by vitrification of nuclear transplant rabbit embryos might be useful though was decreased significantly.

• 한국수정란이식학회지
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• 제7권1호
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• pp.13-19
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• 1992

This study were carried out to investigate the effective concentration of cryoprotective agents and sucrose by one-step straw method, and to determine the optimum thawing temperature and equilibration time of frozen porcine embryos. The porcine embryos foflowing dehydration by cryoprotective agents and a various concentration of sucrose were directly plunged into liquid nitrogen and thawed in 3$0^{\circ}C$ water. Survival rate was defined by FDA test. The results are sunnnarized as follows : 1. The survival rates of porcine embryos after ultrarapid frozen4hawing in the freezing medium with a various concentration of glycerol, DMSO and propanediol added 0.25M sucrose were higher survival rate than those of sucrose concentration of 0.50M. 2. The survival rates of porcine embryos after ultrarapid ftozen4hawing in the freezing medium added 0.25M and 0.SOM sucrose were higher survival rate than those of sucrose concentration of 0.75M and 1.00M. 3. The temperature thawed at 2$0^{\circ}C$ and 3$0^{\circ}C$ resulted in a significantly higher embryos survival rate after 72 hrs in culture than did at 35$^{\circ}C$. 4. The equilibration time on the survival rate of porcine embryos was attained after short period of time(2.5~5 min.) in the freezing medium higher than long period of time(10~20 min.).

• 한국가축번식학회지
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• 제18권1호
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• pp.31-37
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• 1994

This study carried out to investigate the effects of cryoprotectants in the medium on the survival rate of rapidly frozen porcine bisected demi-embryos. The porcine bisected demi-embryos following dehydration by cryoprotectants containing sucrose were directly plunged into liquid nitrogen and thawed in 3$0^{\circ}C$ water bath. Survival rate was defined as development rate on in vitro culture or FDA-test. The results are summarized as follows : 1. The survival rates of without-zona pellucida embryos and 2 blastomeres porcine embryos were 10.0 and 7.1%, respectively. The rate of unfrozen blastomeres (20.00%) was significantly higher than that of non-frozen oocytes. 2. The survival rates of with and without-zona pellucida of bisected porcine embryos by micromanipulator were 20.0 and 14.3%, respectively. 3. The developmental rates of with and without-zona pellucida of bisected poricine embryos by micromanipulator were 13.3 and 7.1%, respectively.