• Toxicological Research
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• v.35 no.4
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• pp.343-351
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• 2019

Many in vitro developmental toxicity assays have been proposed over several decades. Since the late 1980s, we have made intermittent attempts to introduce in vitro assays as screening tests for developmental toxicity of inhouse candidate products. Two cell-based assays which were developed two decades apart were intensively studied. One was an assay of inhibitory effects on mouse ascites tumor cell attachment to a concanavalin A-coated plastic sheet surface (MOT assay), which we studied in the early days of assay development. The other was an assay of inhibitory effects on the differentiation of mouse embryonic stem cell to beating heart cells (EST assay), which we assessed more recently. We evaluated the suitability of the assays for screening in-house candidates. The concordance rates with in vivo developmental toxicity were at the 60% level. The EST assay classified chemicals that inhibited cell proliferation as embryo-toxic. Both assays had a significant false positive rate. The assays were generally considered unsuitable for screening the developmental toxicity of our candidate compounds. Recent test systems adopt advanced technologies. Despite such evolution of materials and methods, the concordance rates of the EST and MOT systems were similar. This may suggest that the fundamental predictivity of in vitro developmental toxicity assays has remained basically unchanged for decades. To improve their predictivity, in vitro developmental toxicity assays should be strictly based on elucidated pathogenetic mechanisms of developmental toxicity.

• Korean Journal of Animal Reproduction
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• v.19 no.4
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• pp.259-264
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• 1996

This study was carried out to investigate on the survival rates and in vitro developmental rates of bisected bovine embryos were by manipulator and micropipette. Bisected embryos were co-cultured in 20% FCS(v/v)＋TCM-199 media containing hormones, oviductal epithelial cells and cumulus cells 0 to 72 hrs after bisection. Survival rate and in vitro fertilization rate were defined as development rate on in vitro culture or FDA-test. The results are summarized as follows ; 1. The in vitro developmental rate of biseciton embryos co-cultured in 20% FCS＋TCM-199 medium containing PMSG, hCG, PMSG＋hCG, hCG＋$\beta$-estradiol 0 to 20 hrs and 20 to 40 hrs were 36.7, 26.7, 33.3, 40.0, and 30.0, and 30.0, 33.3, 30.0, 26.7, and 26.7%, respectively. The survival rate of bisection embryos co-cultured in TCM-199 medium containing hormones was significantly higher than that of non co-culture(25.0%). 2. The in vitro developmental rates of bisection embryos co-cultured in 20% FCS＋TCM-199 medium containing oviductal epithelial cells 4 to 5 hrs and 20 to 24 hrs were 40.0 and 33.3%, respectively. The survival rate of bisection embryos co-cultured in TCM-199 medium containing oviductal epithelial cells was significantly higher than that of non co-culture(25.0%). 3. The in vitro developmental rates of bisection embryos co-cultured in 20% FCS＋TCM-199 medium containing cumulus cells 4 to 5 hrs and 20 to 24 hrs were 43.3 and 36.7%, respectively. The survival rate of bisection embryos co-cultured in TCM-199 medium containing cumulus cells was significantly higher than that of non co-culture (25.0%).

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.113-113
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• 2003

This study was conducted to investigate the effect of vitrification solution(VS) on in vitro developmental competence of immature porcine oocytes. The immature porcine oocytes were exposed to the following vitrification solution, at RT. 1) EFS sol. : 20% ethylene glycol (EG) 3 min, 40% EG + 18%(w/v) Ficoll(MV70, 000) + 0.3 M sucrose 30 sec, 2) GE sol. : 10% glycerol 5 min, 10% G + 20% EG 5 min, 25% G +25% EG 30 sec, 3) EG sol : 1.5M EG 2.5 min, 5.5 M EG + 1.0 M sucrose 30 sec. Oocytes were immediately transferred into 1.0 M, 0.5 M, 0.25 M, 0125 M, 0 M sucrose solution for 2.5 min each at RT. After removal of VS, immature oocytes were matured in vitro and subsequently all oocytes were subjected to IVF followed in vitro culture for 7 days. Maturation rates of oocytes were 38.8%, 44.5%, 22.4% and 57.6%, in EFS, EG, GE and Control, respectively, maturation rates of oocytes in EG and Control was significantly higher than EFS and GE(P<0.01). Fertilization rates of oocytes in Control was significantly higher than other treated groups(P<0.05), but no difference were observed among treated groups. Polyspermic rates were no significant difference among four groups. Cleavage rates of oocytes were 21.9%, 47.1%, 19.0% and 65.9%, in EFS, EG, GE and Control, respectively, cleavage rates of oocytes in EG and Control was significantly higher than EFS and GE(P<0.05), but blastocyst formation rates were no significant difference among four groups. These results suggested that the use of EG solution could be a great challenge for reaching a successful vitrification of immature porcine oocytes.

• Journal of Embryo Transfer
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• v.23 no.2
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• pp.77-80
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• 2008

In the present study, effects of concentration of cryoprotectant solutions on the nuclear maturation of vitrified-thawed porcine oocytes were examined. Also, the developmental capacity of vitrified-thawed immature porcine oocytes following ICSI was investigated. Oocytes were cultured in NCSU-23 medium supplemented with 5% FBS at $38^{\circ}C$ in 5% $CO_2$ and air. The in vitro maturation rate of vitrified-thawed oocytes ($24.1{\pm}2.5%$) was lower than that of the control ($46.0{\pm}3.2%$, p<0.05). The in vitro maturation rate of vitrified-thawed oocytes treated with $1.0{\sim}5.0\;ug$ CB + NCSU- 23 medium were $22.2{\pm}3.0%$, $30.7{\pm}3.2$, $46.3{\pm}3.1%$, $38.5{\pm}3.2%$, respectively. The in vitro maturation rate ($46.3{\pm}3.4%$) of the vitrified-thawed oocytes treated with $3.0\;{\mu}g$ CB for 30 min was the highest of all vitrification groups. When the in vitro developmental rates of the vitrified-thawed (with EDS and EDT) oocytes following ICSI were $18.5{\pm}2.5%$, $16.4{\pm}2.1%$, respectively. This results were lower than the control group ($24.0{\pm}2.5%$).

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.131-136
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• 2011

The in vitro maturation rate of vitrified-thawed canine oocytes was $30.8{\pm}3.4%$. The in vitro maturation rate of vitrified oocytes was lower than that of the control ($52.0{\pm}2.5%$, p<0.05). The in vitro maturation rate of vitrified-thawed oocytes were significantly (p<0.05) lower than those of fresh oocytes. The in vitro maturation and developmental rates of the vitrified-thawed oocytes were $17.5{\pm}2.5%$ and $8.8{\pm}3.4%$, respectively. This results were lower than the control group ($43.6{\pm}3.2%$ vs $20.0{\pm}3.0%$). SOD1 gene expression of 1~2 mm of follicle size were higher than those of above 6 mm follicle size. SOD2 gene expression of 1~2 mm of follicle size were significantly higher than those of above 6 mm follicle size (p<0.01). The expression pattern of SOD1, 2 was constantly expressed in both groups but strongly expressed in follicles (1~2 mm) group when compared to the above 6 mm follicles. SOD gene expression between groups the fresh and vitrified oocytes groups were significant differences in rates. However, RGS gene expression between groups the fresh and vitrified oocytes groups were no significant differences in rates.

• Journal of Embryo Transfer
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• v.22 no.4
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• pp.251-255
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• 2007

This study was carried out to examine on developmental competence of Hanwoo embryos cultured in vitro according to culture conditions and freezing methods. The in vitro developmental competence to blastocyst stage at Day 8 of culture in SOF was significantly (p<0.05) higher than that in CR1aa (30.3% vs. 18.4%). The in vitro developmental rate of morula and blastocysts cultured in group culture was significantly (p<0.05) higher than that in individual culture (41.4% and 36.0% vs. 21.1% and 10.5%, respectively). The cell number of Day 8 blastocysts in group culture was significantly (p<0.05) higher than that in the individual culture ($120.1{\pm}12.8\;vs.\;94.1{\pm}12.1$, respectively). The survival rates of frozen-thawed balstocysts that were exposed in 1.5 M ethylene glycol or 1.5 M ethylene glycol containing 0.1 M sucrose were 77.5% and 78.7%, respectively. The survival rates of blastocysts cultured for 48 h in slow freezing and vitrification was not significantly different (73.3 and 74.0%). In conclusion, in vitro developmental competence of bovine embryos was influenced on the culture medium (SOF) and culture method (Group culture). Survival rate of frozen-thawed of bovine embryos was not influenced on freezing solutions and freezing methods.

• Reproductive and Developmental Biology
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• v.28 no.1
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• pp.53-57
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• 2004

The study was carried out to investigate the effects of morphology, reproductive cycle, incubation time and activation of oocytes on in vitro maturation of cat oocytes and development of IVM/IVF embryos. The results were summarized as follows: 1. When recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage), the developmental rates of oocytes to GV and MI stage were 72.5% and 27.5%, 57.5% and 7.5%, 62.5% and 17.5%, respectively. 2. The developmental rates of oocytes with cumulus cells to GV and MI stage in different conditions of incubation (5% $CO_2$ , 95% $O_2$ and 10% $CO_2$, 90% $O_2$) were 70.0% and 27.5%, 52.5% and 20.0%, 55.0% and 12.5%, respectively. 3. The developmental rates to GV and MI oocytes when cultured at different time of incubation (17∼20, 21∼24, 25∼28 and 29∼32 h) were 67.5% and 20.0%, 67.5% and 30.0%, 62.5% and 22.5%, 65.0% and 15.0%, respectively. 4. The fertilization and cleavage rates of freshly collected oocytes with and without cumulus cells were 72.5% and 25.0%, 37.5% and 7.5%, respectively. The rates were greater in oocytes with cumulus cells than those without cumulus cells. 5. The fertilization and cleavage rates of oocytes recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage) were 75.0% and 25.0%, 40.0% and 7.5%, 50.0% and 15.0%, respectively.

• Journal of Embryo Transfer
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• v.24 no.2
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• pp.121-125
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• 2009

In the present study, effects of concentration of cryoprotectant solutions on the nuclear maturation of vitrifiedthawed bovine oocytes were examined. Also, the developmental capacity of vitrified-thawed immature oocytes following ICSI was investigated. Oocytes were cultured in TCM-199 medium supplemented with 5% FBS at $38^{\circ}$C in 5% $CO_2$ and air. The in vitro maturation rate of vitrified oocytes was 24.5 ${\pm}$ 4.2%. The in vitro maturation rate of vitrified oocytes was lower than that of the control (72.0 ${\pm}$ 3.5%, p<0.05). The in vitro maturation rate of vitrified${\sim}$thawed oocytes incubated in TCM-199 medium supplemented with 1.0${\sim}$5.0 ug CB were 26.7 ${\pm}$ 3.2%, 35.7 ${\pm}$ 3.2%, 54.0 ${\pm}$ 3.0%, 42.5 ${\pm}$ 3.6%, respectively. The in vitro maturation rate (57.0 ${\pm}$ 3.0%) of the vitrified-thawed oocytes treated with 3.0 ${\mu}$g CB for 20 min was the highest of all vitrification groups, although the maturation rate were significantly (p<0.05) lower than those of fresh oocytes. The in vitro maturation rates of the vitrified-thawed (with EDS and EDT) oocytes were 53.8 ${\pm}$ 3.4%, 51.1 ${\pm}$ 3.5%, respectively. This results were lower than the control group (72.0 ${\pm}$ 3.0%). The in vitro developmental rates of the vitrified-thawed oocytes following ICSI were 28.6 ${\pm}$ 4.5%, 25.6 ${\pm}$ 4.3%, respectively. This results were lower than the control group (40.0 ${\pm}$ 4.0%).

• Journal of Embryo Transfer
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• v.8 no.2
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• pp.91-95
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• 1993

The studies on the carried out to investigate the effects of co-culture with uterine fluids and uterine epithelial cells on the in-vitro fertilization and developmental rate of porcine follicular oocytes. The ovaries were obtained from slaughtered swine. The follicular oocytes surrounded with cumulus cells were recovered by aspirating follicular fluids from the visible follicles of diameter 3~5 mm. The follicular oocytes were cultured in TCM-199 medium containing hormones and 10% ECS for 46~48 hrs in a incubator with 5% $CO_2$ 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 results obtained in these experiments were summarized as follows ; 1.The in-vitro maturation and fertilization rate of porcine oocytes co-cultured with uterine fluids in TCM-199 medium were 68.0% arid 55.7%, the rates were higher than of control, 56.5% arid 38.7%. 2. When the in-vitro fertilized oocytes were co-cultured with porcine uterine epithelial cells, the fertilization rate was 60.3%, the rates were higher than that of control, 35.7%. 3. When the in-vitro fertilized oocytes were co-cultured with porcine uterine epithelial cells, the development rate to be blastocyst was 12.4%, the rates were higher than that of control, 9.2%(p<0.05).

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.209-216
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• 1998

The purpose of present study is to improve the efficiency of fusion and the developmental rates of nuclear transplanted embryos to produce genetically identical twins from Korean native cattle. The diameter of aspirated follicles had no significant effect on the recovery rates of oocytes collected by ovum pick-up technique. The fusion rates of nuclear transplanted embryos were significantly higher in 50 and $100{\mu}s$ DC duration groups(73.3 and 72.0% ; respectively) than that in $30{\mu}s$ group(55.6% ; p<0.05). The cleavage rates of nuclear transplanted embryos appeared to be significantly higher in donor nuclei derived from in vivo (65.0%) than in those from in vitro (50.5% ; p<0.01), but the developmental rates to morulae and blastocysts were not significantly different between them(13.7 vs 10.9%, respectively).