• The Korean Journal of Zoology
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• v.34 no.4
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• pp.479-490
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• 1991

포유류 배아의 착상기전을 규명할 목적의 일환으로 자궁내막조직의 탈락막 형성과 분화에 미치는 난소 스테로이드 호르몬의 영향과 인위적 자극등의 영향을 조사하였다. 가임신을 유도시킨 흰쥐와 정상임신군의 자궁내막조직을 착상부위와 비 착상부위로 분리하여 자궁내막조직의 분화에 지표가 되는 Alkaline phosphatase(ALPase)의 활성을 측정하였다. 가임신군에서 인위적 자극(trauma)을 가한 자궁이 자극을 받지않은(control) 자궁에 비해 Progesterone(P)만을, 또는 progesterone과 estradiol(E + P)을 동시 처리받은 실험군에서 ALPase 활성이 유의한 차이(p<0.01)로 높게 나타났다. 정상임신군에서는 착상시기인 임신 제6일군의 착상부위에서 I처리군과 P처리군의 ALPase활성이 비착상 부위에 비해 유의한 차이(P < 0.05)로 크게 나타나며, 특히 임신 제6일군에서는 착상, 비착상 부위의 P처리군의 활성이 Intact군보다 유의하게(P<0.05) 높아졌다. 정상임신 제 9일 Intact군의 ALPase활성은 임신 제3일, 6일의 Intact 군의 활성에 비하여 착상(3, 6일 :P<0.01), 비 착상부위 (3일 :P<0.05, 6일 :P<0.02)에서 다같이 유의한 차이로 높아졌다. 본 연구결과에서 배아가 분화, 발생해 감에따라 자궁내막조직 분화도 활발해지고, 착상부위 분화는 착상시기부터 현저해지며, 특히 P호르몬의 영향이 크다는 것과 배아 아닌 인위적 자극으로도 탈락막 형성 유도가 가능하다는 것을 확인할 수 있었다.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.105-105
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• 2002

염색체의 구조적 이상으로 인한 습관성 유산과 기형아의 출산을 예방하기 위해 착상전 배아에서 할구를 분석하여 정상적인 핵형을 가진 배아만을 이식하는 착상전 유전자 진단 (preimplantation genetic diagnosis, PGD)의 성공적인 임상 적용이 보고되고 있으며, 그 적용 범위가 확대되고 있다. 그러나 일반적인 간기의 핵상을 이용한 PGD에서는 형광직접보합법 probe의 제약으로 보인자와 정상적인 핵형을 구분할 수 없는 단점이 있다. 따라서 본 연구에서는 보다 정확한 PGD를 위해 생쥐 배아를 이용하여 분리한 할구에서 중기 염색체상을 획득하기 위해 미세소관 (microtubule) 형성 저해제를 처리하였으며, 이를 통해 확립된 방법을 인간의 PGD에 적용하고자 하였다. 과배란이 유도된 ICR 생쥐에서 4- 또는 8-세포기 배아를 수획하여 colcemid, nocodazole, vinblastine을 각각 0.1, 0.5, 1.0, 5.0$\mu$M을 처리하고, hoechst 33342로 염색하여 핵상을 관찰하여 최적의 농도를 결정하였다. 또한 각 미세소관 형성 저해제를 혼합 처리하여 가장 높은 중기 염색체상을 획득할 수 있는 혼합 처리를 결정하였다. 이렇게 결정된 혼합 처리 방법을 인간의 체외 수정 및 배아 이식술에서 획득된 3PN 배아에 처리하여 중기 염색체를 획득하였다. Colcemid, nocodazole, vinblastine 모두 1 $\mu$M이 최적 농도임을 확인할 수 있었다 (각각 96.3%, 92.0%, 98,4%). 미세소관 형성저해제를 혼합 처리하였을 경우 nocodazole과 vinblastine (각각 1$\mu$M)을 혼합 처리했을 때 중기 염색체 획득률(97.3%)이 가장 높았다. 인간의 3PN 배아에 1$\mu$M의 nocodazole과 vinblastine을 혼합 처리한 후, 113개의 할구를 분석하여 44개(38.9%)의 할구에서 중기 염색체를 확인할 수 있었다. 본 실험 결과를 통해 중기 염색체를 획득하기 위하여 미세소관 형성 저해제를 처리하는 방법은 생쥐의 배아에서는 효과적이지만, 인간의 배아에서는 그 효율이 다소 낮음을 알 수 있었다. 그러나 이 방법을 개선하여 인간의 할구에서 중기 염색체의 획득률을 높이고, 이를 염색체의 구조적 이상에 대한 착상전 유전자 진단에 적용한다면, 보인자와 정상의 핵상을 구분하여 정상의 핵상만을 갖는 배아의 이식을 통하여 더욱 정확한 착상전 유전자 진단을 시행할 수 있으리라 사료된다.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.27-28
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• 1998

Whole body (fetus)의 경우 수정후 8일부터 10일, 15일까지 계속적으로 증가하였으며, 18일에는 약간 감소하였으나 높게 유지되는 것이 관찰되었다. 간 (liver)에서는 15일에서의 발현이 18일에서보다 높았으며, 뇌 (brain)조직에서도 역시 15일째의 발현이 약간 높았다. 그런데, 모체의 태반에서의 발현을 보면 착상 초기인 8일에 가장 높았으며, 10일, 15일까지 감소하다가 18일에는 매우 약하게 발현되었다. 즉, fetus에서는 착상후 기관형성기에는 대체로 왕성한 발현을 보이다가 기관형성이 마무리되는 시점에 발현이 감소하는 현상이 관찰되었다. 그러나, 태반조직의 경우는 8일이후 계속적으로 발현이 감소되는 것이 관찰되었다. 기관형성기의 배 (embryo)와 태반은 발생시기별 유전자 발현에서 서로 상반된 결과를 보였다.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.2
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• pp.99-110
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• 2008

Objectives: Preimplantation genetic diagnosis (PGD) has become an assisted reproductive technique for couples carrying genetic conditions that may affect their offspring. Osteogenesis imperfecta (OI) is an autosomal dominant disorder of connective tissue characterized by bone fragility and low bone mass. At least 95% of cases are caused by dominant mutations in the COL1A1 or COL1A2. In this study, we report on our experience clinical outcomes with 5 PGD cycles for OI in two couples. Methods: Before clinical PGD, we assessed the amplification rate and allele drop-out (ADO) rate of alkaline lysis and nested PCR protocol using heterozygous patient's single lymphocytes in the pre-clinical diagnostic tests for OI. We performed 5 cycles of PGD for OI by nested PCR for the causative mutation loci, COL1A1 c.2452G>A and c.3226G>A, in case 1 and case 2, respectively. The PCR products were analyzed by agarose gel electrophoresis, restriction fragment length polymorphism (RFLP) analysis with HaeIII restriction enzyme in the case 1 and direct DNA sequencing. Results: We confirmed the causative mutation loci, COL1A1 c.2452G>A in case 1 and c.3226G>A in case 2. In the pre-clinical tests, the amplification rate was 94.2% and ADO rate was 22.5% in case 1, while 98.1% and 1.9% in case 2, respectively. In case 1, a total of 34 embryos were analyzed and 31 embryos (91.2%) were successfully diagnosed in 3 PGD cycles. Eight out of 19 embryos diagnosed as unaffected embryos were transferred in all 3 cycles, and in the third cycle, pregnancy was achieved and a healthy baby was delivered without any complications in July, 2005. In case 2, all 19 embryos (100.0%) were successfully diagnosed and 4 out of 11 unaffected embryos were transferred in 2 cycles. Pregnancy was achieved in the second cycle and the healthy baby was delivered in March, 2008. The causative locus was confirmed as a normal by amniocentesis and postnatal diagnosis. Conclusions: To our knowledge, these two cases are the first successful PGD for OI in Korea. Our experience provides a further demonstration that PGD is a reliable and effective clinical techniques and a useful option for many couples with a high risk of transmitting a genetic disease.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.211-216
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• 1999

One of the problems in a refrigerator operation is the frost formation on a cold surface of the evaporator. The frost layer is formed by the sublimation of water vapor when the surface temperature is below the freezing point. This frost layer is usually porous and formed on the cold surface of the evaporator. The frost layer on the surface of a evaporator will make side effect such as thermal resistance. However, these important factors have not been used in determining the defrosting period. In this report, a prediction taking into account the change of the fin efficiency due to the growth of the frost layer.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2002.02a
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• pp.10-10
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• 2002

• Korean Journal of Animal Reproduction
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• v.18 no.2
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• pp.141-150
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• 1994

Morphological features of the interaction between the hatching blastocyst and implantation in pig were studied by electron microscopy. The observations extended from late blastocyst stage to the completion of trophoblastic erosion of the epithelium and early decidual transformation of the epithelium and early decidual transformation of the stromal cells. Between day 7 and 17 of pregnancy, blastocysts from 0.3 to 12 mm in diameter were flushed from the uterine horns of Dutch Landrace pigs. On the 7th of development in the pig blastocyst, the blastocyst shedded of the zona pellucida established the tips of microvilli and with bleb-like cytoplasmic protrusions of the epithelial cells. From day 11 on in pig embryo, the bilayered trophoblast undergoes a dramatic phase of elongation so that the initially spherical expanded blastocyst becomes tubular. In pig, close apposition to the uterine wall beg-ins at about 12 $^1$/$_2$ days and then attachment occurred during the afternoon of the 16th or 18th day post coitum. At this stage, embryonic loss compared with corpus luteum number is up to 40% of ovulated oocytes. Therefore, the implantation failture of these embryos may be mainly caused by morphological abnormality and failture of zona shedding.

• Journal of Radiation Protection and Research
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• v.21 no.4
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• pp.273-284
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• 1996

Embryos and fetuses are more sensitive to various environmental agents than are adults or children. The biological effects such as intrauterine death and malformation are closely connected with prenatal exposure very various agents. The sensitivity of these embryonic/fetal effects depends on the stage of pregnancy. From the viewpoint of fetal development, embryonic and fetal stages can be divided into three stages : Preimplantation, organogenetic and fetal. Each stage corresponds to 0 to 4.5days, 4.5 to 13.5days, and 13.5days of gestation in mice, respectively. Many studies on the biologcal effects of mice irradiated by ${\gamma}-rays$ at various stages during organogenesis and fetal period have been performed. Based on these results, the dose-effect and dose-response relationships in malformations, intrauterine death, or retardation of the physical growth have been practically modeled by the ICRP(International Commission on Radiological Protection) and other international bodies for radiation protection. Many experimental studies on mice have made it clear that mice embryos in the preimplantation period have a higher sensitivity to radiation for lethal effects than the embryos/fetuses on other prenatal periods. However, no eratogenic effects of radiation at preimplantation stages of mice have been described in many textbooks. It has been believed that 'all or none action results' for radiation of mice during the preimplantation period were applied. The teratogenic and lethal effects during the preimplantation stage are one of the most important problems from the viewpoint of radiological protection, since the preimplantation stage is the period when the pregnancy itself is not noticed by a pregnant woman. There are many physical or chemical agents which affect embryos/fetuses in the environment. It is assumed that each agents indirectly effects a human. Then, a safety criterion on each agent is determined independently. The pregnant ICR mice on 2, 48, 72 or 96 hours post-conception (hpc), at which are preimplantation stage of embryos, were irradiated whole body Cesium-gamma radiation at doses of 0.1, 0.25, 0.5, 1.5, and 2.5 Gy with dose rate of 0.2 Gy/min. In the embryos from the fetuses from the mice irradiated at various period in preimplantation, embryonic/fetal mortalities, incidence of external gross malformation, fetal body weight and sex ratio were observed at day 18 of gestation. The sensitivity of embryonic mortalities in the mice irradiated at the stage of preimplantation were higher than those in the mice irradiated at the stage of organogenesis. And the more sensitive periods of preimplantation stage for embryonic death were 2 and 48 hpc, at which embryos were one cell and 4 to 7 cell stage, respectively. Many types of the external gross malformations such as exencephaly, cleft palate and anophthalmia were observed in the fetuses from the mice irradiated at 2, 72 and 96 hpc. However, no malformations were observed in the mice irradiated at 48 hpc, at which stage the embryos were about 6 cell stage precompacted embryos. So far, it is believed that the embryos on preimplantation stage are not susceptible to teratogens such as radiation and chemical agents. In this study, the sensitivity for external malformations in the fetuses from the mice irradiated at preimplantation were higher than those in the fetuses on stage of organogenesis.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.3
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• pp.181-189
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• 2010

The placenta, which is a temporary organ derived from the fetus during pregnancy, is critical to support fetus development via optimal regulation between mother and fetus. Trophoblast as a major cell population of the placenta is one of the earliest to differentiate and shows an extensive proliferation or/and differentiation up to the formation of the placenta. The role of the trophoblast show dynamic changes from early embryo implantation to placentation during pregnancy. Implantation of the blastocyst into the endometrium of the maternal uterus is mediated by invasion of the differentiated trophoblast (e.g. syncytiotrophoblast) from the trophectoderm. During pregnancy, the unique role of the trophoblast is to invasion, eroding, and metastasizing in the placenta as well as to ensure appropriate bidirectional nutrient or waste flow required for growth and maturation of the embryo. The dysfunction of the trophoblast during pregnancy can result in several gynecological diseases including preeclampsia and congenital malformation in neonatal medicine. Therefore, trophoblasts act as a conclusive factor in placental and fetal development. This brief review outlines the classification of trophoblast and its function in the placenta during pregnancy. Also, we introduce the latest research in trophoblast for implantation and the placenta development, and the application potential of trophoblast for infertility and obstetrical diseases.

• 대한생식의학회:학술대회논문집
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• 2007.11a
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• pp.106.2-107
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• 2007