• Development and Reproduction
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• v.25 no.4
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• pp.213-223
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• 2021

Controlled ovarian hyperstimulation (COH) is routinely used in the in vitro fertilization and embryo transfer (IVF-ET) cycles to increase the number of retrieved mature oocytes. However, the relationship between repeated COH and ovarian function is still controversial. Therefore, we investigated whether repeated ovarian stimulation affects ovarian aging and function, including follicular development, autophagy, and apoptosis in follicles. Ovarian hyperstimulation in mice was induced by intraperitoneal injection with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG). Mice subjected to ovarian stimulation once were used as a control group and 10 times as an experimental group. Repeated injections with PMSG and hCG significantly reduced the number of primary follicles compared to a single injection. The number of secondary and antral follicles increased slightly, while the number of corpus luteum increased significantly with repeated injections. On the other hand, repeated injections did not affect apoptosis in follicles associated with follicular atresia. The expression of autophagy-related genes Atg5, Atg12, LC3B, and Beclin1, cell proliferation-related genes mTOR, apoptosis-related genes Fas, and FasL was not significantly different between the two groups. In addition, the expression of the aging-related genes Dnmt1, Dnmt3a, and AMH were also not significantly different. In this study, we demonstrated that repeated ovarian stimulation in mice affects follicular development, but not autophagy, apoptosis, aging in ovary. These results suggest that repetition of COH in the IVF-ET cycle may not result in ovarian aging, such as a decrease in ovarian reserve in adult women.

• 대한생식의학회:학술대회논문집
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• 1997.11a
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• pp.77-78
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• 1997

• 대한생식의학회:학술대회논문집
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• 2006.11a
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• pp.153.2-154
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• 2006

• Clinical and Experimental Reproductive Medicine
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• v.41 no.2
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• pp.41-46
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• 2014

IVM refers to the maturation of immature oocytes in culture after their recovery from small antral follicles at the stage prior to selection and dominance. IVM requires little or no FSH in vivo and has been proposed as an alternative to conventional IVF, since it reduces the primary adverse effects caused by controlled ovarian stimulation, including the ovarian hyperstimulation syndrome. Moreover, IVM is a promising option for cases for which no standard protocol is suitable, such as FSH resistance, contraindications for ovarian stimulatory drugs, and the need for urgent fertility preservation. Recently, IVM has been used in women with regular cycles and normal ovaries. However, the pregnancy rate following IVM is suboptimal compared with that of conventional IVF, indicating that further studies to optimize the protocol and the culture conditions are warranted.

• 한국생태학회:학술대회논문집
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• 2002.08a
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• pp.71-77
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• 2002

For landscape ecological management of the isolated forestlands in Incheon city located in the western tip of South Korea, the forest vegetation of Mt. Cheolma was classified phytosciologically and mapped out its spatial distribution at a scale of 1:5,000. Characteristics of forest landscape structures were discussed in terms of the number and size of patches obtained by analyzing vegetation map. Units to manage the forest vegetation were categorized into eighteen communities, seventeen groups, and sixteen subgroups. Landscape elements were classified into five types: secondary vegetation, introduced vegetation for forestry (IVF), introduced vegetation for agriculture (IVA), and other elements. Two hundred and ninety-three forest landscape patches covers 443.3ha of which IVF accounted for 316.8ha(71.5%), the largest portion, secondary vegetation for f01.2ha(22.8%), IVA for 6.2ha(1.4%), and others for 19.1ha(4.3%). The ratio of natural forest elements of 31.9% showed that this area was mainly comprised of artificially introduced vegetation, such as Robinia pseudoacacia plantation and Pinus rigida plantation. Forest landscape patches have a mean area of 4.5ha, a density of 66.1/100ha, and a diversity index of 0.87. It was estimated that differentiation of patches recognized in community level would be related to human interference and those in subordinate level to natural processes.

• The Korean Journal of Ecology
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• v.25 no.4
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• pp.205-211
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• 2002

For landscape ecological management of the isolated forestlands in Incheon city located in the western tip of South Korea, the forest vegetation of Mt. Cheolma was classified phytosciologically and mapped out its spatial distribution at a scale of 1:5,000. Characteristics of forest landscape structures were discussed in terms of the number and size of patches obtained by analy zing vegetation map. Units to manage the forest vegetation were categorized into eighteen communities, seventeen groups, and sixteen subgroups. Landscape elements were classified into five types: secondary vegetation, introduced vegetation for forestry (IVF), introduced vegetation for agriculture (IVA), and other elements. Two hundred and ninety-three forest landscape patches covers 443.3ha, of which IVF accounted for 316.8ha(71.5$\%$), the largest portion, secondary vegetation for 101.2ha(22.8$\%$), IVA for 6.2ha(1.4$\%$), and others for 19.1ha(4.3$\%$). The ratio of natural forest elements of 31.9$\%$ showed that this area was mainly comprised of artificially introduced vegetation, such as Robinia pseudoacacia plantation and Pinus rigida plantation. Forest landscape patches have a mean area of 4.5ha, a density of 66.1/100ha, and a diversity index of 0.87. It was estimated that differentiation of patches recognized in community level would be related to human interference and those in subordinate level to natural processes.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.51-58
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• 1998

본 연구는 체외수정 프로그램에 참여하는 환자에 있어서 난자회수 이틀째의 자궁내막의 발달상태를 알아보기 위하여 pinopode의 발달상태, 에스트로젠 및 프로제스테론 수용체의 발현을 관찰하였다. 생검한 자궁내 막 조직 을 양분하여, 절반은 전사전자 현미경 (scanning electron microscope)으로 pinopode를 관찰하기 위하여 2.5% glutaraldehyde와 2% paraformaldehyde로 고정하였고, 나머지 절반은 dating 및 스테로이드 수용체의 면역조직화학적 측정 (immunocytochemistry)을 위하여 10% formalin으로 고정하였다. 모두 12명의 환자중 8명에서 pinopode가 관찰되었으며, pinopode 발달이 관찰되지 않은 환자들은 hCG 주사를 맞는 날의 estradiol (E2)의 혈중농도가 600 pg/mL이하로 낮았다. 본 연구의 결과로부터 자궁내막의 발달상태를 알아보기 위해서는 지금까지 일반적으로 사용되어 오던 dating이나 스테로이드 수용체의 면역조직화학적 측정법 이외에도 pinopode를 관찰함으로써 조금 더 정확한 진단을 할 수 있으리라고 사료되며, pinopode의 발달은 E2의 혈중농도와 관계가 있을 것으로 추정된다.

• Clinical and Experimental Reproductive Medicine
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• v.34 no.3
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• pp.197-205
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• 2007

Objective: This study evaluated the pregnancy and implantation rates in fresh IVF-ET cycles or frozen-thawed ET (F-ET) cycles based on serum estradiol concentrations of controlled ovarian hyperstimulation (COH). Methods: Clinical outcomes of 1,565 cycles of fresh IVF-ET with COH and 670 cycles of F-ET were retrospectively analyzed. Serum estradiol levels on the day of human chorionic gonadotropin (hCG) administration were categorized into Group-A (1,000$\sim$2,000 pg/ml), Group-B (2,000$\sim$3,000 pg/ml), Group-C (3,000$\sim$4,000 pg/ml) and Group-D (> 4,000 pg/ml). Clinical pregnancy (CPR), implantation (IR) and delivery rates (DR) were compared among four groups subdivided into younger (< 35 years) and older ($\geq$ 35 years) women. Statistical analysis was performed by Student's t-test and chi-square test. Results: Overall clinical outcomes with fresh IVF-ET and F-ET cycles were similar: 41.2% vs 44.8% of CPR, 18.8% vs 19.6% of JR, and 33.2% vs 34.5% of DR, respectively. There were no significant differences in the clinical outcomes of all four groups between fresh IVF-ET and F-ET cycles of younger women according to the estradiol levels. However, the clinical outcomes of F-ET cycles of older women in Group-D were significantly higher than those of fresh IVF-ET cycles (51.3% vs 25.0% of CPR*, 18.6% vs 9.9% of IR and 33.3% vs 19.4% of DR;* p<0.05). Conclusion: Our results demonstrated that supraphysiological levels of estradiol during COH in fresh IVF-ET cycles of older women ($\geq$ 35 years) may be detrimental to implantation environments of endometrium and clinical outcomes, which could be improved by F-ET cycles.

• Clinical and Experimental Reproductive Medicine
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• v.32 no.1
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• pp.47-54
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• 2005

Objective: Evaluation of embryos using early cleavage to 2-cell stage has been proposed, but a critical time-point for selecting embryos is unclear. The aim of the present study is to provide a guideline including critical time-point in the selection of early cleaving embryo for the reduction of multiple pregnancies as well as the increase of pregnancy rate in human IVF. Methods: This prospective study was performed in 116 cycles from 85 patients who underwent conventional IVF or ICSI at the infertility clinic of Good Moonhwa Hospital from January 2002 to December 2003. Early cleavage (EC) of embryos to 2-cell stage was assessed at 25 h and 27 h postinsemination/microinjection. Embryos that had early cleaved at each time point were designated as EC-1 and EC-2, respectively, while others were designated as non-early cleavage (NEC). Results: At least one early cleavage embryo was observed in 54 (46.6%) for the EC-1 and 84 (72.4%) for the EC-2 of the 116 cycles assessed. Clinical pregnancy rates (PR) were significantly higher in the EC-1 group (66.7%) compared to the EC-2 group (53.6%) or the NEC group (31.2%) (p<0.05). Significant improvement of the pregnancy rate was found when at least two or more embryos were early cleaved at 25 h postinsemination or when the proportion of early cleavage embryo at 25 h postinsemination was higher than 20% (p<0.05). Conclusion: The critical time-point for the selection of early cleavage embryos with high implantation potential is more effective in 25 h postinsemination/microinjection compared to 27 h. The proportion as well as number of early cleavage embryos is also an important factor for the prediction of pregnancy outcome and the chance of multiple pregnancies. These results demonstrated that the evaluation of early cleavage embryos to 2-cell stage is an easy, simple, and objective method for the selection of good quality embryos suitable for embryo transfer.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.2
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• pp.171-181
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• 1995

Ovarian hyperstimulation syndrome(OHSS) is one of the well-known complication of controlled ovarian hyperstimulation(COH). Though there have been numerous measures to prevent the occurrence of OHS, it has not been completely preventable until now. The fluid shift from the intravascular space to the third space is due to decreased oncotic pressure of the serum. The objective of this study was to evaluate if IV administration of 20% albumin in those patients with OHSS risk can make prevention of severe OHSS. We retrospectively analysed 70 patients undergoing IVF-ET who had serum peak estradiol($E_2$) level of >2,500 pg/ml and/or the number of oocytes retrieved over 20. The treatment group(n=39) received albumin while the control group(n=31) did not. After 40 grams of human albumin diluted in 1,000 ml of 0.9% sodium chloride solution, the treatment group received half of the fluid during oocyte retrieval, the remainder in the recovery suite. The results were as follows; There were significant differences in the levels of serum peak $E_2$ and number of oocytes retrieved between the two groups(p<0.05). However, there were no significant differences in the incidence of OHSS and pregnancy rate or multifetal pregnancy rate. In conclusion, administration of albumin to OHSS risk patients did not reduce the rate of OHSS in IVF-ET. However, if we consider the fact that there were differences in the level of peak serum $E_2$ and oocyte numbers, further prospective study may be needed.