• Asian-Australasian Journal of Animal Sciences
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• v.15 no.3
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• pp.445-452
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• 2002

The main objective of modern reproductive technologies in pig reproduction is to increase reproductive efficiency and rates of genetic improvement. They also offer potential for greatly extending the multiplication and transport of genetic materials and the conservation of unique genetic resources in reasonably available forms for possible future use. The development and refinement of these technologies is concentrating on gamete and embryo collection, sorting and preservation, in vitro production of embryos, culturing, manipulation of embryos (splitting, nuclear transfer, production of chimeras, establishment embryo stem cells, and gene transfer) and embryo transfer. Also, the development of these novel technologies is facilitated by modern equipment for ultrasonography, microscopy, cryopreservation, endoscopy, and flow cytometry, microinjectiors, micromanipulators and centrifugation. The real impact on herd productivity will come from combining new reproductive techniques with powerful DNA technologies. The new reproductive techniques will allow a rapid turnover of generations, whereas the DNA technology can provide selection, which does not need phenotypic information when the selection decisions are made.

• Clinical and Experimental Reproductive Medicine
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• v.32 no.4
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• pp.353-359
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• 2005

Heterotopic pregnancy is named when an extrauterine (ectopic) pregnancy coexists with an intrauterine pregnancy simultaneously by many causes such as PID (pelvic inflammatory disease), endometriosis, IUD (intrauterine device), previous pelvic surgery and others. This is very rare in general population, with a range of occurrence estimated between 1:7963 and 1:30000. But recently the incidence has increased as the uses of ARTs (assisted reproductive technologies) including ovulation induction, IVF-ET (in-vitro fertilization and embryo transfer) and GIFT (gamete intrafallopian transfer) increase. Because this has high maternal morbidity, mortality and fetal loss, early diagnosis and proper management is very important. We report a case of heterotopic pregnancy following IVF-ET with a brief review.

• Clinical and Experimental Reproductive Medicine
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• v.16 no.1
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• pp.103-106
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• 1989

Gamete intrafollopian transfer, a varient of IVF, is becoming increasingly popular as a treatment modality for infertility in women with at least one healthy follopian tube. Although GIFT has recently been poprlarized as a safe and effective treatment in selected infertile couples, little discussion of potential complications has been published. Whereas a tubal pregnancy rate of approximately 5% has been noted for IVF, early reports of GIFT have noted ectopic pregnancy to be relativiely rare. We experienced a case of combined pregnancy following GIFT with microsurgery and now present it with brief review of related literatures.

• BMB Reports
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• v.43 no.6
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• pp.389-399
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• 2010

Fertilization is a complex process comprised of numerous steps. During fertilization, two highly specialized and differentiated cells (sperm and egg) fuse and subsequently trigger the development of an embryo from a quiescent, arrested oocyte. Molecular interactions between the sperm and egg are necessary for regulating the developmental potential of an oocyte, and precise coordination and regulation of gene expression and protein function are critical for proper embryonic development. The nematode Caenorhabditis elegans has emerged as a valuable model system for identifying genes involved in fertilization and the oocyte-to-embryo transition as well as for understanding the molecular mechanisms that govern these processes. In this review, we will address current knowledge of the molecular underpinnings of gamete interactions during fertilization and the oocyte-to-embryo transition in C. elegans. We will also compare our knowledge of these processes in C. elegans to what is known about similar processes in mammalian, specifically mouse, model systems.

• Korean Journal of Poultry Science
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• v.15 no.2
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• pp.67-71
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• 1988

In order to induce the diploid gamete(ovum) under suppression of meiosis in oogenesis for production of polyploid chicken. this experiment checked meiosis time. through regular ovulation and response of inhibitor (Tri-ethylen Melamine) to meiosis. The results obtained was follows; ＊Meiosis of oogenesis was 2-4 hours before ovulation. ＊Response of inhibitor to meiosis was effective at 0.3mg triethylen melamine per kg body weight. ＊Fertility was highly decreased by influence from inhibitor. ＊66% of fertilized eggs was triploid(3n) through fertilization induced diploid ovum (2n) with normal sperm(n).

• The Korean Journal of Malacology
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• v.14 no.1
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• pp.1-8
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• 1998

자웅이체인 배벌레(shipworm), Zachsia zenkewitschi의 생식에 관하여 연구를 진행하였다. 자성 생식기관은 하나의 난소와 소형의 웅성을 안고 있는 한 쌍의 외투막 주머니로 구성되어 있었다. 소형 웅성의 정소는 내장 신경절 주위에 위치하였다. 성숙된 알의 지름은 60$\mu\textrm{m}$이고 난황과 젤리막으로 싸여 있었다. Zachsia zenkewitschi의 정자는 약 2.6$\mu\textrm{m}$의 원추상 두부, 0.5$\mu\textrm{m}$의 첨체, 직경 약 0.9 $\mu\textrm{m}$의 중부로 되어 있었다.

• Proceedings of the KSAR Conference
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• 2001.10a
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• pp.25-31
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• 2001

During early development, a dramatic reduction in methylation levels occurs in mouse (Monk et al., 1987). The process of epigenetic reprogramming in early embryos erases gamete-specific methylation patterns inherited from the parents (Howlett ＆ Reik 1991, Monk et al., 1987, Oswald et al., 2000, Sanford et al., 1984). This genome-wide demethylation process may be a prerequisite for the formation of pluripotent stem cells that are important for the later development (Reik ＆ Surani 1997). During post-implantation development, a wave of de novo methylation takes place; most of the genomic DNA is methylated at defined developmental timepoints, whereas tissue-specific genes undergo demethylation in their tissues of expression (Kafri et al., 1992, Razin ＆ Kafri 1994). Another demethylation-remethylation cycle of epigenetic reprogramming takes place during gametogenesis and is necessary for resetting of genomic imprinting (Solter 1988). The dynamic epigenetic reprogramming events appear to be basic and are probably conserved in eutherian mammals (see below). (omitted)

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.1006-1010
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• 1995

This paper describes Sexual Reproduction Genetic Algorithm(SRGA) for function optimization. In SRGA, each individual utilize a diploid chromosome structure. Sex cells(gametes) are produced through artificial meiosis in which crossover and mutation occur. The proposed method has two selection operators, one, individual selection which selects the individual to fertilize, and the other, gamete selection which makes zygote for offspring production. We consider the effects of multi-selection and diploidy on search performance. SRGA improves local and global search(exploitation and exploration) and show optimum tracking performance in nonstationary environments. Gray coding is incorporated to transforming the search space and Genic uniform distribution method is proposed to alleviate the problem of premature convergence.

• The Korean Society of Law and Medicine
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• v.10 no.1
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• pp.77-116
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• 2009

Owing to the development of Biotechnology, the involvement of humans in life before birth has been increasing. This means the need for the protection of unborn life takes on new importance. The respect for life and human beings which is based on fundamental constitutional principle should still be respected under civil law. This study examines how methods of respect for life are embodied in civil liability law. In particular, it enunciates the protection of unborn life within time-flow. Lastly, it studies the instruments of the civil liability law and the extent of protection for a fetus from the process of fertilization of an ovum by a sperm, development into an embryo and implantation. Especially, it looks into when and how the subject of the right changes. Besides, it critically scrutinizes the opinions of leading case lawyers and the Constitutional Court which conclude that, in order for a fetus to become the subject of Damage law, it is required to be born alive to comply with precedent. Furthermore, it suggests an alternative interpretation theory.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.1
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• pp.31-39
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• 1992

By means of the results of In vitro fertilization(IVF) of supernumerary oocytes, the possibility of predicting a pregnancy outcome following gamete intrafallopian transfer(GIFT) and the prognostic implications for future pregnancy were evaluated in 46 GIFT cycles excluding simultaneous program of GIFT and IVF from February, 1989 to July, 1991. IVF of supernumerary oocytes were identified in 21 cycles, but not in remaining 25 cycles. There was no significant difference in age, duration and etiologic factors of infertility, and serum levels of FSH, LH and $E_2$ on MCD #3 and $E_2$ on the day of hCG injection between fertilized(N=21) and unfertilized group(N=25). The number of oocytes retrieved was similar in both groups. The number of supernumerary oocytes available for IVF after transfer was $5.43{pm}2.95$ ranging from 2 to 12. The prenancy rate in fertilized group, 33.3%(7/21), was higher without statistical significance, compared with 8.0%(2/25) in unfertilized group. Using IVF of supernumerary oocytes as a test of pregnancy following GIFT, sensitivity was 77.8 %; specificity, 61.2%; positive predictive value(PPV), 33.3%; negative predictive value(NPV), 92%. The fertilization rate of supernumerary oocytes in pregnant group, $86.4{\pm}22.8%$ was significantly higher compared with $56.1{\pm}20.2%$ in nonpregnant group. In cases with fertilization rate ${\geq}80%$, pregnancy was expected with PPV of 85.7%. In conclusion, IVF of supernumerary oocytes in GIFT program can be a profitable method as a prognostic indicator of pregnancy following GIFT. More aggressive diagnostic and therapeutic measures should be performed in cases with failure in IVF of supernumerary oocytes.