• Clinical and Experimental Reproductive Medicine
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• 제44권1호
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• pp.15-21
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• 2017

Objective: The aims of this study were to investigate whether fertilization could induce the resumption of meiosis in mouse oocytes arrested at metaphase I (MI) after in vitro maturation (IVM), and to investigate the effect of $Ca^{2+}$ chelator treatment at the time of fertilization on the transition from MI to metaphase II (MII). Methods: MII-stage and arrested MI-stage mouse oocytes after IVM were fertilized, and then embryonic development was monitored. Blastocysts from each group were transferred into 2.5 days post-coitum pseudo-pregnant ICR mice. MI oocytes after IVM were treated with a $Ca^{2+}$ chelator to investigate the effect of $Ca^{2+}$ oscillations on their maturation. Results: As insemination time increased, the number of oocytes in the MI group that reached the MII stage also increased. The blastocyst rates and total cell numbers in the MII group were significantly higher than in the MI group. No pregnancy occurred in the MI group, but 10 pregnancies were achieved (10 of 12) in the MII group. The proportion of MI oocytes that matured to MII oocytes after fertilization was significantly higher in the non-treated group than in the $Ca^{2+}$ chelator-treated group. Conclusion: The findings that a higher proportion of MI-arrested oocytes progressed to MII after fertilization and that the MI-to-MII transition was blocked by $Ca^{2+}$ chelator treatments before fertilization indicate that the maturation of MI oocytes to MII oocytes is associated with intracellular $Ca^{2+}$ oscillations driven by fertilization.

• Reproductive and Developmental Biology
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• 제30권1호
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• pp.7-11
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• 2006

본 연구는 호르몬과 Na-pyruvate의 첨가가 개 미성숙난자의 체외성숙에 미치는 영향을 검토하였다. 개의 발정주기와 관계없이 암캐의 난소에서 회수한 난자를 NCSU-37 배양액에서 72시간 체외 배양하였다. 호르몬의 영향을 검토하기 위하여 배양액 중에 다양한 호르몬을 $24{\sim}72$시간 첨가하여 성숙율을 검사하였으며, Na-pyruvate 첨가 농도의 영향을 검토하였다. $E_2$ 단독 첨가구에서는 제2감수분열 중기(MII) 단계까지 성숙이 관찰되었으나(5.7%), 타 처리구에서는 MII기까지의 성숙이 이루어지지 않았다(P<0.05), $E_2$를 $6{\sim}24$시간만 처리하였을 때는 MII기로 성숙되는 난자가 없었으나 72시간 처리하였을 때는 6.0%로 유의적으로 높게 나타났다(P<0.05). Na-pyruvate의 농도를 0.25 mM 첨가한 구보다 2.5 mM 첨가한 구에서 제1감수분열 중기(MI) 단계까지의 성숙율이 증가하는 경향을 보였으나, MII 단계까지의 성숙율은 차이가 없었다. 본 실험의 결과는 개 난자의 체외성숙시 $E_2$가 첨가된 배양액에서 72시간 배양시에 성숙율을 증진시킬 수 있으나, Na-pyruvate의 농도는 개 체외배양에 있어 큰 영향을 미치지 않는 것을 나타낸다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권1호
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• pp.13-22
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• 2014

Esophageal pH monitoring is considered the gold standard for the diagnosis of gastroesophageal reflux disease because of the normal ranges across the pediatric age range. However, this method can only detect acid reflux. Multichannel intraluminal impedance-pH (MII-pH) monitoring has recently been used for the detection of bolus reflux in infants and children. This method allows for the detection of liquid, gas or mixed reflux in addition to acid, weakly acidic or weakly alkaline reflux. MII-pH monitoring can record the direction of flow and the height of reflux, which are useful parameters to identify an association between symptoms and reflux. However, the technique is limited by its high cost and the lack of normative data of MII-pH in the pediatric population. Despite certain limitations, MII-pH monitoring will become more common and gradually replace pH monitoring in the future, because pH monitoring is part of MII-pH.

• 한국발생생물학회지:발생과생식
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• 제8권1호
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• pp.35-42
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• 2004

미성숙의 Germinal Vesicle(GV 단계에서 성숙한 Metaphase II(MII) 단계가 되는 난자성숙 과정은 핵과 세포질의 성숙을 통해 이루어지며, 이를 통해 수정과 배 발달을 할 수 있는 능력을 갖게 된다. GV 난자는 prophase I 단계에 arrest 되어 있다가 meiosis 과정을 거쳐 성숙한 MII로 되는데 이를 조절하는 기작에 대해서는 거의 알려져 있지 않다. 따라서 본 연구는 미성숙 난자와 성숙 난자간의 유전자 발현의 차이를 동정함으로써 난자성숙에 관여하는 유전인자를 밝히고자 하였다. GV와 MII 난자에서 mRNA를 정제한 후 ACP System을 이용하여 두 그룹간의 유전자 발현 차이를 분석하여 양적으로 서로 다르게 발현하거나 한쪽에서만 특이적으로 발현하는 유전자를 cloning하여 Sequencing과 BLAST search를 통해 분석하였다. ACP 1번부터 20번까지를 사용하여 32개의 유전자를 찾았으며 이중 26개가 기능적으로 알려진 유전자였다. Pscd2를 포함한 4개의 유전자는 GV에 특이적으로 발현하였고, PKD2와 CSN3를 포함하는 10개의 유전자는 GV에서 더 높게 발현하였으며 Diva를 포함하는 12개의 유전자는 MII에서 더 높게 발현하였다. 본 연구를 통해 분석된 모든 유전자는 난자에서의 발현은 보고되지 않은 것으로 ACP System을 통해 최초로 동정되었으며 특히 PKD-CSN Signaling pathway가 난자에서 발현함을 알 수 있었다. 본 연구는 난자 성숙 과정에서 서로 다르게 발현하는 유전인자를 성공적으로 동정하였으며 향후 이들의 기능을 연구함으로써 난자성숙 조절기전을 연구하는데 기여할 것으로 사료된다.

• Reproductive and Developmental Biology
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• 제31권2호
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• pp.71-76
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• 2007

Previous studies have shown that BMI-1026 is a potent inhibitor of the cyclin-dependent kinases (cdk). In cell culture, the compound also arrests G2/M strongly and G1/S and S weakly. Two key kinases, cdk1 (p34cdc2 kinase) and mitogen-activated protein (MAP) kinase (erk1 and 2), perform crucial roles during oocyte maturation and, later, metaphase II (MII) arrest. In mammalian oocytes, both kinases are activated gradually around the time of germinal vesicle breakdown (GVBD) and maintain high activity in eggs arrested at metaphase II. In this study, we examined the effects of BMI-1026 on GVBD and MII arrest in mouse oocytes. BMI-1026 inhibited GVBD of immature oocytes and activated MII-arrested oocytes in a concentration-dependent manner, with more than 90% of oocytes exhibiting GVBD inhibition and MII activation at 100 nM This is approximately 500$\sim$1,000 times more potent than the activity reported for the cdk inhibitors roscovitine (${\sim}50{\mu}M$) and butyrolactone (${\sim}100{\mu}M$). Based on the results of previous in vitro kinase assays, we expected BMI-1026 to inhibit only cdk1 activation in oocytes and eggs, not MAP kinase. However, in our cell-based system, it inhibited the activity of both kinases. We also found that the effect of BMI-1026 is reversible. Our results suggest that BMI-1026 inhibits GVBD and activates MII-arrested oocytes efficiently and reversibly and that it also inhibits both cdk1/histone HI kinase and MAP kinase in mouse oocytes.

• Clinical and Experimental Reproductive Medicine
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• 제28권2호
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• pp.111-120
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• 2001

Objective: To verify the expression of leptin receptor (OB-R) in oocytes and preimplantation embryos, the involvement of mitogen activated protein kinase (MAPK or Erk1/2) in the leptin signaling, and effect of leptin on the oocyte maturation in mice. Method: RT-PCR analysis of OB-R was conducted in germinal vesicle (GV)-intact and MII stage oocytes, and 1, 2, 8-cell embryos and blastocysts. Germinal vesicle breakdown (GVB), polar body extrusion, monitored in the presence or absence of leptin ($1{\mu}M$). Following the leptin treatment, temporal changes in MAPK activity were verified by immunoprecipitation and in vitro kinase assay in MII oocytes. Results: The expression of OB-R mRNA was found in GV and MII oocyte but not in the embryos. MAPK activity of the MII oocytes was significantly increased by brief incubation in the HTF supplemented with leptin ($1{\mu}M$). Priming of PD098059, a MEK inhibitor to leptin treatment attenuated the activation of MAPK by leptin in MII oocytes. Following 24 hrs of culture of the GV oocytes, leptin significant increased the GVB and 1 st polar body extrusion. Conclusion: This result suggested that functional interaction between leptin and OB-R resulted in potentiation of MAPK (Erk1/2) activity in MII oocytes through MEK activation and that leptin might be a local regulator of meiotic maturation of the mouse oocytes.

• Journal of Veterinary Science
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• 제21권3호
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• pp.48.1-48.18
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• 2020

Background: Mature oocytes at the metaphase II status (MII-stage oocytes) played an important role in assisted reproductive technology in non-human primates. Objectives: In order to improve the proportion of MII-stage oocytes retrieval, three different superovulation protocols were performed on 24 female cynomolgus monkeys. Methods: All the monkeys received once-daily injection of follicle-stimulating hormone (25 international unit [IU]) on day 3 of the menstruation, 3-day intervals, twice daily for 8-12 days until the time of human chorionic gonadotropin (1,500 IU) injection, on the 14-17th day of menstruation collecting oocytes. The difference between protocol I and protocol II was that 0.1 mg the gonadotropin-releasing hormone agonist was injected on day 1 of the menstruation, while the difference between personalized superovulation protocol and protocol II was that oocytes could be collected on the 14-17th day of menstrual cycle according to the length of each monkey. Results: The total number of oocytes harvested using the personalized superovulation protocol was much higher than that using protocol I (p < 0.05), and the proportion of MII-stage oocytes was significantly greater than that from either superovulation protocol I or II (p < 0.001 and p < 0.01 respectively), while the proportion of immature oocytes at the germinal vesicle was less than that from superovulation protocol I (p < 0.05). Conclusions: The personalized superovulation protocol could increase the rate of MII-stage oocytes acquired, and successfully develop into embryos after intracytoplasmic sperm injection, and eventually generated fetus.

• Clinical and Experimental Reproductive Medicine
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• 제40권1호
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• pp.7-11
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• 2013

Objective: We evaluated the fertilization potential of immature oocytes obtained from controlled ovarian hyperstimulation cycles of patients undergoing ICSI. Methods: We retrospectively analyzed 463 ICSI cycles containing at least one immature oocyte at oocyte denudation. ICSI was performed on mature oocytes at oocyte denudation (metaphase-II [MII] oocytes) and the oocytes that extruded the first polar body between oocyte denudation and ICSI (MI-MII oocytes). Fertilization and early embryonic development were compared between MII and MI-MII oocytes. To investigate the pregnancy potential of MI-MII oocytes, the pregnancy outcome was analyzed in 24 ICSI cycles containing only immature oocytes at retrieval. Results: The fertilization rate of MI-MII oocytes (37.0%) was significantly lower than that of MII oocytes (72.3%). The rates of delayed embryos and damaged embryos did not significantly differ. Eighty-one immature oocytes were retrieved in 24 cycles that retrieved only immature oocytes and 61 (75.3%) of them were in the MI stage. ICSI was performed on 36 oocytes (59.0%) that extruded the first polar body before ICSI and nine MI-MII oocytes (25.0%) were fertilized. Embryo transfers were performed in five cycles. Pregnancy was observed in one cycle, but it ended in biochemical pregnancy. Conclusion: In ICSI cycles, oocytes that extruded the first polar body between denudation and ICSI can be used as a source of oocytes for sperm injection. However, their fertilization and pregnancy potential are lower than that of mature oocytes. Therefore, ovarian stimulation should be performed carefully for mature oocytes obtained at retrieval, especially in cycles with a small number of retrieved oocytes.

• Reproductive and Developmental Biology
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• 제31권3호
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• pp.169-174
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• 2007

개 난자의 체외성숙율을 높이기 위하여 다양한 방법들이 시도되고 있지만 여전히 그 효율성은 낮다. 본 연구는 개 난자의 체외성숙 시, 성선 자극 호르몬인 황체형성호르몬(LH)과 난포자극호르몬(FSH), 상피세포성장인자(Epidermal growth factor, EGF) 그리고 시스테인(cysteine)을 각각 첨가하여 72시간 동안 체외성숙시킨 후 핵성숙율(GV: germinal vesicle, GVBD: germinal vesicle break down, MI: metaphase I, MII: metaphase II, UK: unknown stage)을 확인하였다. LH와 FSH를 첨가하였을 때 첨가하지 않은 군과 GV, MI 및 MII율에는 유의적인 차이는 없었다. 하지만 GVBD율은 첨가군이 유의적으로(p<0.05) 높았다. 성선 자극 호르몬을 첨가한 배지에 10ng/ml의 EGF를 첨가하였을 때 MII율이 첨가하지 않은 군보다 유의적으로(p<0.05) 높았다(4.54% vs. 7.06%). cysteine을 첨가하였을 경우, 핵성숙율에 유의적인 차이는 보이지 않았지만 전반적으로 핵성숙율이 향상된 것을 확인할 수 있었다. 따라서 개 난자의 체외성숙 시, $10 {\mu}g/ml$의 LH와 FSH, 10ng/ml의 EGF 그리고 0.57mM의 cysteine을 첨가하는 것이 핵성숙율을 향상시키는 것으로 사료된다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권3호
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• pp.256-264
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• 2021

Purpose: Data on the relationship between gastroesophageal reflux (GER) and brief resolved unexplained events (BRUE) in infants is scarce. The aim of this study was to identify the characteristics of combined multichannel intraluminal impedance-pH (MII-pH) monitoring in infants who have experienced BRUE. Methods: We conducted a prospective study of infants who were hospitalized on account of BRUE and required 24-hour MII-pH monitoring. Results: Twenty-one infants (mean age, 4.7 months; range, 0.9-8.9 months; male/female, 11/10) participated in this study. BRUE symptoms associated with GER were found in 10 infants (47.6%). Based on the RI on pH-metry alone, only 7 (33.3%) infants were diagnosed with GERD. More than 100 GER episodes detected by MII were found in 10 (47.6%) infants. Nineteen percent of infants were diagnosed with GERD based on both pH and MII. Conclusion: Both acid and non-acid reflux seem to play a significant role in the pathogenesis of GER-related BRUE in infants.