• Development and Reproduction
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• v.21 no.4
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• pp.351-359
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• 2017

Implantation is a highly organized process that involves an interaction between a receptive uterus and a competent blastocyst. In humans, natural fecundity suggests that the chance of conception per cycle is relatively low (~30%) and two-third of lost pregnancies occur because of implantation failure. Defective implantation leads to adverse pregnancy outcomes including infertility, spontaneous miscarriage, intrauterine fetal growth restriction and preeclampsia. With use of advanced scientific technologies, gene expression analysis and genetically-engineered animal models have revealed critical cellular networks and molecular pathways. But, because of ethical restrictions and the lack of a mechanistic experiment, comprehensive steps in human implantation have still not been completely understood. This review primarily focuses on the recent advances in mechanisms of implantation. Because infertility is an emerging issue these days, gaining an understanding the molecular and hormonal signaling pathway will improve the outcome of natural pregnancy and assisted reproductive technology.

• Proceedings of the KSAR Conference
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• 2001.10a
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• pp.48-49
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• 2001

While transgenic manipulation in mice have been very successful the same is not true for cattle and pigs. The inability to isolate ES cells from the bovine and porcine has precluded the utilization of the gene targeting technology in these species. Fortunately new advances in cloning by nuclear transfer have opened up a unique opportunity to undertake precise genetic modification in cattle and pigs. The ability of a number of different laboratory groups to successfully clone cattle is due to numerous research programs focused on nuclear transfer in cattle, and the enormous base of knowledge developed over the last 20 years involving the application of assisted reproductive techniques in cattle. Successful and repeatable procedures for in vitro oocyte maturation, in vitro fertilization, and in vitro embryo culture are now well established for cattle. In our laboratory we have utilized nuclear transfer to reproduce the genotypes of several animals, selected for cloning based on their inherent genetic value. Results that we have obtained to date are similar to those reported by other laboratories. (omitted)

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.12-18
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• 1998

Tremendous progress has been made over the past quarter-century studying the genetics of gametogenesis and the resulting gametes and embryos. Studies merging molecular techniques and conventional cytogenetics are now beginning to bridge the gap between what we have learned about the meiotic process in males and females and what we know of the mitotic chromosomes of zygotes. Numerical abnormalities in sperm, oocytes and embryo can now diagnosed by fluorescence in situ hybridization (FISH). "At risk" couples can, therefore, have only unaffected embryos replaced in the sterus and avoid the possibility of terminating a pregnancy that might only be diagnosed as affected later gestation. Single-cell genetic analysis has also provided powerful tools for studying genetic defects arising during early human development. Recent studies of sperms, oocytes and cleavage-stage human embryos have revealed an unexpectedly high incidence. These genetic abnormalities are likely to contribute to early pregnancy loss and have important implications for improving pregnancy rates in infertile couples by assisted reproduction. The widespread use of preimplantation genetic diagnosis (PGD) awaits further documentatio of safety and accuracy. Other issues also must be addressed. First, the ethical issues regarding germ cell and embryo screening must be addressed including what diseases are serious enough to warrant the procedure. Another concern is the use of this technology for non-genetic disorders such as gender selection. Finally, the experimental nature of these procedure must continually be discussed with patients, and long-term follow-up studies must be undertaken. Development of more accurate and less expensive assays coupled with improved assisted reproductive technology success rates may make PGD a more widely use clinical tool. The future awaits these development.velopment.

• Development and Reproduction
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• v.8 no.1
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• pp.1-9
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• 2004

The potential importance of proteomic approaches has been clearly demonstrated in other fields of human medical research, including liver and heart disease and certain forms of cancer. However, reproductive researches have been applied to proteomics poorly. Proteomics can be defined as the systematic analysis of proteins for their identity, quantity, and function. It could increase the predictability of early drug development and identify non-invasive biomarkers of toxicity or efficacy. Proteome analysis is most commonly accomplished by the combination of two-dimensional gel electrophoresis(2DE) and MALDI-TOF(matrix-assisted laser desorption ionization-time of flight) MS(mass spectrometry) or protein chip array and SELDI-TOF(surface-enhanced laser desorption ionization-time of flight) MS. In addition understanding the possessing knowledge of the developing biomarkers used to assess reproductive biology will also be essential components relevant to the topic of reproduction. The continued integration of proteomic and genomic data will have a fundamental impact on our understanding of the normal functioning of cells and organisms and will give insights into complex cellular processes and disease and provides new opportunities for the development of diagnostics and therapeutics. The challenge to researchers in the field of reproduction is to harness this new technology as well as others that are available to a greater extent than at present as they have considerable potential to greatly improve our understanding of the molecular aspects of reproduction both in health and disease.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.451-455
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• 2015

The buffalo is an important livestock resource in several countries of South Asia and the Mediterranean regions. However, reproductive efficiency is compromised due to known problems of biological and management origins, such as lack of animal selection and poor nutrition. Under optimal conditions puberty is attained at 15 to 18 months in river buffalo, 21 to 24 months in swamp buffalo and is influenced by genotype, nutrition, management and climate. However, under field conditions these values deteriorate up to a significant extant. To improve reproductive efficiency, several protocols of oestrus and ovulation synchronization have been adopted from their use in commercial cattle production. These protocols yield encouraging pregnancy rates of (30% to 50%), which are comparable to those achieved in buffaloes bred at natural oestrus. The use of sexed semen in buffalo heifers also showed promising pregnancy rates (50%) when compared with conventional non-sexed semen. Assisted reproductive technologies have been transferred and adapted to buffalo but the efficiency of these technologies are low. However, these latest technologies offer the opportunity to accelerate the genetic gain in the buffalo industry after improving the technology and reducing its cost. Most buffaloes are kept under the small holder farming system in developing countries. Hence, future research should focus on simple, adoptable and impact-oriented approaches which identify the factors determining low fertility and oestrus behaviour in this species. Furthermore, role of kisspeptin needs to be explored in buffalo.

• Reproductive and Developmental Biology
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• v.37 no.4
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• pp.169-174
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• 2013

Sperm capacitation refers to polymerization of filamentous (F)-actin from globular (G)-actin. While the role of actin-related protein 2/3 (Arp2/3) complex in actin polymerization is well appreciated, the underlying mechanism(s) and its relationship with capacitation are poorly understood. Therefore, to evaluate the potential role of Arp2/3 complex on capacitation, bovine spermatozoa were incubated with multiple doses (1, 10 and $100{\mu}M$) of CK-636, an inhibitor of Arp2/3 complex with heparin. The cellular localization of the Arp2/3 complex in spermatozoa was identified by immunohistochemistry, whereas western blot was also applied to detect the protein tyrosine phosphorylation of sperm proteins. Additionally, sperm motility and kinematic parameters were evaluated using a computer-assisted sperm analysis system. CK-636 resulted in significant changes in the ratio of Arp2/3 complex localization between acrosome and equatorial region of the spermatozoa. Short-term exposure of spermatozoa to $100{\mu}M$ of CK-636 significantly decreased sperm motility, however a non-detectable effect on protein tyrosine phosphorylation was observed during capacitation. On the basis of these results, we propose that Arp2/3 complex is associated with morphological changes during capacitation and compromised sperm motility.

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.241-246
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• 2010

The objective of this study was to investigate the effect of storage time on fresh boar semen in Androhep and Beltsville Thawing Solution (BTS). Boar semen samples extended in each extender were stored at $17^{\circ}C$ up to 4 days. Sperm motility kinematics was evaluated by computer assisted sperm analyzer (CASA) and capacitation status by chlortetracycline (CTC)/Hoechst 33258 staining. Sperm motility (%) was not decreased during storage in BTS and Androhep. No significant difference between extenders was observed. Only significant differences in kinematic parameters on linearity during storage were found. The percentage of dead sperm significantly decreased during storage (p<0.05). Also the percentage of noncapacitated, capacitated, and acrosome-reacted sperm significantly modified during storage (p<0.05). However, there was no significant difference between extenders except proportion of capacitated sperm. This finding supported that modification in these parameters was not significantly different between extenders during this short-term storage. Our finding strongly indicated that both Androhep and BIS maintained favorable conditions for motility, motility kinematics, and capacitation status during short-term storage. Despite modifications in some parameters were apparent during sperm storage in extenders, these may not affect the fertilizing capacity of boar semen.

• Reproductive and Developmental Biology
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• v.35 no.1
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• pp.47-54
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• 2011

Endocrine disruptors bind to hormone receptors on sperm membrane, therefore spermatozoa are potentially a useful model for examining estrogenic activities of endocrine disruptors. The objective of this study was to compare the effects of two xenoestrogenic compounds [genistein (Gen) and 4-tert-octylphenol (OP)] to those of two steroids [estrogen ($E_2$) and progesterone ($P_4$)] on boar sperm % motility and motion kinematics of in vitro. Porcine spermatozoa were incubated with various concentrations ($0.001{\sim}100\;{\mu}M$) of each chemical for 15 or 30 min, and then assessed % motility and sperm motion kinematics using computer assisted sperm analyzer (CASA). Each chemical decreased sperm % motility, and OP decreased VSL and VAP compared with untreated control(p<0.05). $E_2$ stimulated the motion kinematic changes except VCL. Moreover, Gen had effects on VCL and VAP alterations after 30 min incubation. In summary, since all chemicals studied effectively altered sperm % motility and motion kinematics, it was concluded that porcine spermatozoa could be a useful model for in vitro screening of potential endocrine disruptors.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.1
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• pp.85-93
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• 2003

Objective : To evaluate the safety and efficacy of selective fetal reduction (SFR) and compare the outcome of twin pregnancy after SFR in multiple pregnancy induced by assisted reproductive technology (ART) with that of natural twin pregnancy. Methods : From September 1995 to March 2002 in Ajou University Hospital, SFR was performed in 79 patients whose gestational sacs were more than 3. Of these 79 patients, 47 patents resulted in twin pregnancy after SFR. SFR was performed using transvaginal intracardiac KCl injection at gestational age of $6{\sim}9$ weeks. Control group was composed of 264 patients with natural twin pregnancy, who delivered after intrauterine pregnancy at 24 weeks, from June 1994 through December 2002. We compared Obstetric and perinatal outcomes between SFR group and natural twin group. Results: Among 47 patients with twin pregnancy after SFR, 2 spontaneous abortion were occurred at intrauterine pregnancy at 8 and 19 weeks. Obstetrical and perinatal outcomes were available in 43 patients. Single intrauterine fetal death was occurred in 1 of 43 (2.3%) patients in SFR group. Incidence of preterm labor, premature rupture of membrane, preeclampsia and placenta previa were similar, but gestational diabetes mellitus (GDM) was occurred more frequently in SFR group (3 (7.0%) vs 4 (1.5%), p=0.02). Mean gestational age, mean birth weight, incidence of discordancy, use of intubation and ventilation, incidence of fetal anomaly, low (<7) Apgar score and intrauterine growth restriction were similar in both groups. Conclusion: Twin pregnancy after SFR has the increased incidence for GDM but other obstetric and perinatal outcome was similar compared with natural twin pregnancy. So SFR is a safe and effective procedure, so we suggest SFR is needed in multifetal pregnancy more than triplet.

• Journal of Animal Science and Technology
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• v.56 no.4
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• pp.15.1-15.10
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• 2014

Background: Morphologically classifying embryos is important for numerous laboratory techniques, which range from basic methods to methods for assisted reproduction. However, the standard method currently used for classification is subjective and depends on an embryologist's prior training. Thus, our work was aimed at developing software to classify morphological quality for blastocysts based on digital images. Methods: The developed methodology is suitable for the assistance of the embryologist on the task of analyzing blastocysts. The software uses artificial neural network techniques as a machine learning technique. These networks analyze both visual variables extracted from an image and biological features for an embryo. Results: After the training process the final accuracy of the system using this method was 95%. To aid the end-users in operating this system, we developed a graphical user interface that can be used to produce a quality assessment based on a previously trained artificial neural network. Conclusions: This process has a high potential for applicability because it can be adapted to additional species with greater economic appeal (human beings and cattle). Based on an objective assessment (without personal bias from the embryologist) and with high reproducibility between samples or different clinics and laboratories, this method will facilitate such classification in the future as an alternative practice for assessing embryo morphologies.