• Journal of Embryo Transfer
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• v.21 no.3
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• pp.199-205
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• 2006

The objective of this study was to investigate the resumption of postpartum ovarian cyclicity, and to determine the relationship between concentrations of plasma urea nitrogen (PUN) and resumption of ovarian cyclicity in Holstein cows. The cows were considered to have resumed ovarian cyclicity on the day of ovulation, if followed by regular ovarian cycles. 58.8 percentage of the cows (114/194) had normal resumption of ovarian cyclicity (resumption within 40days after calving), and 41.2% (80/194) had delayed resumption (resumption did not occur until> 40days after calving). Delayed resumption Type I (one or more ovarian cycles with luteal phase> 20days, i.e. prolonged luteal phase; 17.5%) and delayed resumption Type II (first ovulation did not occur until ${\ge}40days$ after calving, i.e. delayed first ovulation 22.7%) were the most common types of delayed resumption. 18 percentage of the cows (35/194) did not resume their ovarian cyclicity until 60days postpartum. Prolonged luteal phase and delayed first ovulation were two important ovarian dysfunctions that delayed postpartum resumption of cyclicity in dairy cows. Cows with PUN of <15, $15{\sim}19.9\;and\;{\ge}20mg/dl$ had the likelihood ratios of normal ovarian cyclicity of 0.9, 1.14 and 0.55, respectively. Thus, PUN concentration of $15{\sim}19.9mg/dl$ had a favorable association with postpartum resumption of cyclicity, whereas lower or higher PUN had a negative association with postpartum resumption of cyclicity.

• Korean Journal of Animal Reproduction
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• v.27 no.1
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• pp.87-93
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• 2003

This study was conducted to investigate the effects of embryo development by fusion condition on the nuclear transfer with brindle coated cow's ear cells. Ear cells were transferred into an enucleated oocyte and fused with cytoplasm in the fusion condition with 1.9kv/cm, 2.0kv/cm, 2.1kv/cm each 10 and 20ug duration Nuclear transfer embryo were activeted with a combination of 5ug/ml and 1.9mM 6-DMAP (4min, 4h). Fusion rate was 51∼68% range among fusion condition (1.9, 2.0, 2.1kv/cm; 10, 20us). But, cytoplasm lysis rate was increased by higher electric condition (0∼51.8% range). Each parameter's cleavage and blastocyst formation rate were 1.9kv/cm for 10us (75.8 and 19.5%), 20us (69.8 and 48.6%), 2.0kv/cm for 10us (76.9 and 20.0%), 20 us (68.5 and 40.9%), 2.1kv/cm for 10us (70.5 and 44.2%), 20 us (68.5 and 27.0%). We compared the effectiveness of cloning for between brindle coated cow's ear cells and Hanwoo fetal fibroblast cells. There was no significant differences in the fusion rate and developmental rate to the blastocyst stage. After transfer of blastocysts derived from nuclear transfer embryos, pregnancy rates of the Hanwoo fetal fibroblast cells and brindle coated cow's ear cells were checked pregnant on day 60 as assessed by ultrasonography, 40% (2/5) and 15.8% (3/19), respectively. This studies conclude that brindle coated cow's ear cells have the developmental potentiality to term by nuclear transfer. These results demonstrate that the increased the field strength was to be profitable for development of blastocyst or reduce of cytoplasm's damage than increasing the pulse duration.

• Journal of Embryo Transfer
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• v.21 no.1
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• pp.13-20
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• 2006

The purpose of this study was to develope the transgenic cattle expressing hFSH into the urine using the nuclear transfer. To produce the interest gene in urine, the specific vector was ligated with hFSH gene undo. maUII promoter. The fetal fibroblast cells (KbFF) were isolated from a 45-day male fetus. The hFSH gene was co-transfected with pcDNA3 (neo) vector to KbFF cells by electroporation. The gene-transfected cells were cultured with G-418 selection medium for 2 weeks. Selected colonies were confirmed by PCR. For nuclear transfer, enucleated bovine oocytes were transferred with hFSH transfected or nontransfected fetal fibroblasts. The cleavage and blastocyst formation rates were significantly lower (p<0.05) in cloned embryos transfected with hFSH gene (68.7% and 15.7%) than in those non-transfected (67.6% and 24.5 %), respectively. Apoptosis analysis showed no difference between hFSH transfected and non-transfected blastocysts (p>0.05). The blastocysts were transfected to 77 (control 24, hFSH 53) recipient cows. Two calves were born (1.9%) following transfer with NT embryos transfected with hFSH gene, but they were confirmed not to be transgenic calves. This result shows that the hFSH colonies were mixed with transfected and non transfected cells. Further research will be needed for selection and establishment of gene transfected cells.

• Clinical and Experimental Reproductive Medicine
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• v.15 no.2
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• pp.135-147
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• 1988

To compare the stimulation effect of the ratio in follicle stimulating hormone and luteinizing hormone in induction of multiple follicular growth, the serum $E_2$ level, the diameter of follicle, number of aspirated follicles and cleavage rate of in vitro fertilized preovulatory oocytes as well as the pregnancy rate were evaluated. Forty one patients with irreparable tubal disease were stimulated by hMG(n=24) or FSH/hMG(n=17) for the purpose of in vitro fertilization and embryo transfer. The following results were obtained. 1. Serum estradiol($E_2$) levels on the day of hCG administration were $921.0{\pm}353.3\;pg/ml$ in hMG group and $1272.9{\pm}1060.6\;pg/ml$ in FSH/hMG group. The serum $E_2$ value of hMG group was significantly lower than that of FSH/hMG group. 2. The diameter of leading follicle by ultrasonogram on the day of hCG administration were $16.2{\pm}2.0\;mm$ in hMG group and $16.2{\pm}2.6\;mm$ in FSH/hMG group. No significant difference of follicle diameter between two groups was demonstrated. 3. The number of follicles with diameter above 10 mm by sonogram on the day of hCG injection were $3.91{\pm}2.32$ in hMG group and $6.52{\pm}3.86$ in FSH/hMG group. There was significant difference of number of follicles between two groups, (p< 0.01). 4. The number of oocytes found per patient at aspiration were $2.59{\pm}1.00$ in hMG group and 3. $76{\pm}2.31$ in FSH/hMG group. There was significant difference of number of aspirated oocytes between two groups. (p< 0.05). 5. The detection rate of preovulatory oocyte at aspiration were 68.4%(39/57) in hMG group (n=22) and 77.6%(38/49) in FSH/hMG group (n=13). 6. The cleavage rate of preovulatory oocyte at 44 hours after insemination were 74.4%(29/39) in hMG group(n=22) and 81.6%(31/38) in FSH/hMG group (n=13). When only hMG was used, one pregnancy was established in 15 patients to whom 29 zygotes were transferred. And a full term normal female baby was delivered by elective cesarean section. In the FSH/hMG group, five pregnancies out of 9 transferred patients were confirmed by serum ${\beta}-hCG$. Two pregnancies were spontaneously aborted before the 6th week of pregnancy. One patient aborted her baby at the 18th week of pregnancy because of incompetent internal os of the cervix. Two patients delivered two full term babies by elective cesarean section. From the above findings, paralell with the increase in the ratio of exogenous follicle stimulating hormone to luteinizing hormone, an increase in oocyte recovery was observed as well as an improvements in pregnancy rate. It was concluded that FSH enrichment early in the follicular phase had a beneficial effect in the controlled ovarian hyperstimulation.

• Journal of Embryo Transfer
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• v.21 no.3
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• pp.177-182
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• 2006

This study was conducted to investigate the effects of melengesterol acetate (MGA) and $PGF_{2{\alpha}}$ administrations on serum progesterone level, synchrony of estrus and conception rates in Han-woo. Firstly, ten heifers and one freematin were fed 0.5 mg MGA/day for 14 days in a grain carrier, and after 19 days of MGA feeding, a single injection of 25 mg $PGF_{2{\alpha}}$ were treated. Blood samples were collected to evaluate serum progesterone concentrations from the start of feeding of MGA until the end of feeding and subsequent estrous detection and artificial insemination (AI) at 3 days intervals, and on days of $PGF_{2{\alpha}}$ injection, estrous detection, AI, and 15th and 60th days after AI. The level of progesterone in the blood began to increase from 7 days after MGA feeding, and 9 days after feeding it became 5.4 ng/ml and maintained that level thereafter. On the 33th day when the $PGF_{2{\alpha}}$ was injected, it reached the peak level of 7.6 ng/ml. However, 2-3 days after $PGF_{2{\alpha}}$ injection, it dropped to 1.4 ng/ml drastically (p<0.05). Secondly, one hundred and ninety four Hanwoo heifers or cows were divided into two groups to compare estrous induction and conception rates: the one treated with MGA and $PGF_{2{\alpha}}$, (n=104) and the other with $PGF_{2{\alpha}}$ treatment (two injections at 11 days interval, n=90). The heifers or cows treated with MGA and $PGF_{2{\alpha}}$ were identical to those used as above. The percentages of heifers or cows showed estrus were higher in the $MGA+PGF_{2{\alpha}}$ treatment (91.3%) than in the $PGF_{2{\alpha}}$ treatment (72.2%, p<0.05). Conception rates were also higher in the $MGA+PGF_{2{\alpha}}$ treatment (94.2%) than in the $PGF_{2{\alpha}}$ treatment (88.9%, p<0.05). The results of this experiment indicate that estrus synchronization using $MGA+PGF_{2{\alpha}}$ is more effective than that using $PGF_{2{\alpha}}$ (two injections) in Hanwoo.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.4
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• pp.367-372
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• 2000

Objective: This study was performed to evaluate whether vitrification method could be used for the cryopreservation of human blastocysts derived from IVF program. Methods: Surplus embryos were obtained from consented IVF patients. Controlled ovarian hyperstimulation was done with midluteal GnRH agonist, gonadotropin and hCG. After oocyte retrieval and insemination, fresh embryo transfer was done at $4{\sim}8$ cell stage. The surplus embryos after ET were cultured in blastocyst medium up to 6 days after oocyte retrieval. Obtained blastocysts were cryopreserved with our vitrification method. Blastocysts were exposed to 1.5 Methylene glycol (EG) in phosphate buffered saline (PBS) for 2.5 minutes, followed by 5.5 M EG plus 1 M sucrose for 20 seconds. Then 1 to 3 blastocysts were mounted on electron microscope (EM) grid and the grid was plunged into liquid nitrogen for storage. For thawing, blastocyst-containing EM grids were sequentially transferred in 1.0 M, 0.5 M, 0.25 M, 0.125 M and 0 M sucrose solution at the intervals of2.5 minutes. And blastocysts were cultured for about 6 hours and only re-expanded blastocysts were transferred to uterus of the patients on 4 to 5 days after ovulation in natural cycle or on 18 to 19 day of artificial cycle. Results: From Oct. 1998 to Jul. 1999, 34 patients were agreed to participate in this study. The mean age and duration of infertility of the patients were 31.6 years and 4.1 years, respectively. Among 34 cycles. replacements could be done in 20 cycles (58.8%). A total 93 blastocysts were thawed and 48 (51.6%) of them survived. Thirty-eight blastocysts, mean 1.9 embryos per patient, were transferred, resulting in 5 clinical pregnancies which consisted of 1 triplet, 2 sets of twins and 2 singleton pregnancies. The pregnancy rate per transfer was 25% and implantation rate was 23.6%. Five patients delivered 7 healthy babies including 2 sets of twins at term. Conclusion: Successful pregnancies and deliveries were established after transfer of vitrified human blastocysts. Vitrification using ethylene glycol as cryoprotectant and electron microscope grid is a rapid and simple method that can be effectively applied for the cryopreservation of human blastocysts.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.487-495
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• 2007

The objectives of the present study were to initiate cloning of Korean native goat by somatic cell nuclear transfer (NT) and to examine whether unovulated (follicular) oocytes can support the same developmental ability of NT embryos as ovulated (oviductal) oocytes after hCG injection in stimulated cycles of the goat. The in vivo-matured and immature oocytes were collected from the oviducts and follicles of superovulated does, respectively, and the immature oocytes were maturated in vitro. Ear skin fibroblasts derived from a 3-yr-old female Korean native goat were used as the donors of nuclei or karyoplasts. Following fusion, activation and in vitro culture to a 2- to 4-cell stage, 49 in vitro-derived and 105 in vivo-derived embryos were transferred to 6 and 17 recipient does, respectively. One doe and three does of the respective groups were identified as pregnant by ultrasonography on day 30 after embryo transfer. However, only one doe, which had received in vivo-derived embryos, delivered a normal female kid of 1.9 kg on d 149. The cloned kid gained more weight than her age-matched females as much as 87% during the first 4 mo after birth (17.7 vs. $9.4{\pm}0.8$ kg) and reached puberty at 6-mo age a few months earlier than normal female does. The telomere length of the kid, which was similar to that of the donor fibroblast at 2-mo age, decreased 8% between 2- and 7-mo ages. Moreover, at 7-mo age, she had 21% shorter telomere than her age-matched goats. To our knowledge, this is the first case in which a cloned animal born with a normal weight exhibited accelerated growth and development. The unusually rapid growth and development of the cloned goat may have resulted from SCNT-associated epigenetic reprogramming involving telomere shortening.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.3
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• pp.135-142
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• 2018

Objective: To prospectively evaluate the efficacy and safety of a fixed early gonadotropin-releasing hormone (GnRH) antagonist protocol compared to a conventional midfollicular GnRH antagonist protocol and a long GnRH agonist protocol for in vitro fertilization (IVF) in patients with polycystic ovary syndrome (PCOS). Methods: Randomized patients in all three groups (early antagonist, n = 14; conventional antagonist, n = 11; long agonist, n = 11) received 21 days of oral contraceptive pill treatment prior to stimulation. The GnRH antagonist was initiated on the 1st day of stimulation in the early antagonist group and on the 6th day in the conventional antagonist group. The GnRH agonist was initiated on the 18th day of the preceding cycle. The primary endpoint was the number of oocytes retrieved, and the secondary endpoints included the rate of moderate-to-severe ovarian hyperstimulation syndrome (OHSS) and the clinical pregnancy rate. Results: The median total number of oocytes was similar among the three groups (early, 16; conventional, 12; agonist, 19; p= 0.111). The early GnRH antagonist protocol showed statistically non-significant associations with a higher clinical pregnancy rate (early, 50.0%; conventional, 11.1%; agonist, 22.2%; p= 0.180) and lower incidence of moderate-to-severe OHSS (early, 7.7%; conventional, 18.2%; agonist, 27.3%; p= 0.463), especially among subjects at high risk for OHSS (early, 12.5%; conventional, 40.0%; agonist, 50.0%; p= 0.324). Conclusion: In PCOS patients undergoing IVF, early administration of a GnRH antagonist may possibly lead to benefits due to a reduced incidence of moderate-to-severe OHSS in high-risk subjects with a better clinical pregnancy rate per embryo transfer. Further studies with more subjects are required.

• Korean Journal of Animal Reproduction
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• v.24 no.1
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• pp.49-57
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• 2000

This study was conducted to investigate the developmental potential of cloned embryos derived from bovine fetal fibroblast cells, and the effect of quiescent treatment, passage number and origin of donor cells on in vitro development of cloned embryos. Fetal skin and liver-derived fibroblast cells were transferred to enucleated oocytes after serum starvation or nontreatment (cycling). After electrofusion. reconstituted embryos were activated with $Ca^{＋＋}$-ionophore and cycloheximide, and cocultured for 7~9 days with BRL cells. Some blastocysts were transferred to recipient cows 7~8 days post estrus. The development rate to the blastocyst stage of serum starved cell-derived embryos was higher (25.3%) than that of actively dividing cells-derived embryos (15.9%), The rates of blastocyst formation were 23.1~25.0% after transfer of cell passaged 4 to 6 times, and 23.8 and 25.2% after transfer of fetal skin and liver cells, respectively. After embryo transfer, 34.4% and 15.6% of recipient cows were pregnant on Day 60 and 120, respectively, and one male calf was produced from skin-derived vitrified blastocyst. The result of this study showed that the development of cloned embryos. was enhanced by quiescent treatment, but did not different among the cells passaged 4 to 6 times, and between skin and liver cells. This result also confirms that offspring can be obtained from the vitrified clone embryo derived from fetal skin cell.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.239-244
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• 1998

The purpose of this study is compare IVF cycle outcome in poor responders between clomiphene citrate (CC) stimulated and controlled ovarian hyperstimulation (COH) protocol. A total of 94 patients responding poorly in previous IVF cycles (estradiol<600 pg/ml or less than 3 oocytes retrieved) subsequently underwent either COH (COH group: 122 cycles, 68 patients) or CC-stimulated cycles (CC group: 43 cycles, 26 patients). CC was administered for five consecutive days starting on cycle day 3 at a dose of 100 mg daily. Serial transvaginal ultrasound examination was done from cycle day 8. Urine was collected $3\sim4$ times before hCG injection for the detection of LH surge. The hCG was administered when serum estradiol reached greater than 150 pg/ml and mean follicle diameter>16 mm. In COH group, ovarian stimulation was done using short protocol (GnRH-a/FSH/HMG/hCG). No difference in age or number of transferred embryos was found between CC group and COH group. COH group had significantly (p<0.05) higher mean peak level of $E_2$ ($810{\pm}112$ vs $412{\pm}55$ pg/ml) and greater number of retrieved oocytes ($3.0{\pm}0.2$ vs $2.0{\pm}0.2$) than CC group. CC group had transferred embryos $(1.8{\pm}0.2)$ compared with $(2.1{\pm}0.2)$ in COH group. However, CC group had higher pregnancy rate than COH group per retrieval [26.9% (7/26) vs 6.2% (6/97)], or per transfer [31.8% (7/22) vs 7% (6/86)]. Although cycle cancellation rate in CC group (48.8%) was higher than that of COH group (21.3%), the pregnancy rate per cycle in CC group was still higher (16.3%) than COH group (4.9%). In addition, implantation rate in CC group was 17.5% (7/40), which was significantly (p<0.01) higher than 3.9% (7/180) in COH group. These data suggest that oocyte and embryo quality are lower in COH cycles of poor responders than CC cycles. We suggest that clomiphene citrate stimulated IVF cycle may be more efficient than COH IVF cycle in poor responders in terms of lower costs and higher pregnancy performance.