• Reproductive and Developmental Biology
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• v.30 no.2
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• pp.99-105
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• 2006

The growing oocytes become progressively capable of resuming meiosis, and full meiotic competence appear when they are about 80% of the size of fully grown oocytes. As hormonal influences vary at different stages of reproductive cycle, the size of oocytes may vary according to the reproductive stages. The present study was designed to compare the diameter between the ovulated and freshly collected immature canine oocytes. The ovulated oocytes were collected 72 hr after ovulation by oviductal tube flushing by laparotomy under general anesthesia. Immature oocytes were collected by ovarian slicing method. Diameter of all oocytes was measured directly using epiflurescence microscope with a calibrated micro-eyepiece micrometer at ${\times}200$ magnification. The thickness of zona pellucida and diameter of cytoplasm were measured separately and recorded. A total of 2209 zona intact oocytes were collected, among them 628 from anestrus, 675 from follicular, 838 from luteal and 68 by fallopian tubes flushing methods. The average number of oocytes was 104.7, 168.8, 119.7 and 11.3 for anestrus, follicular, luteal and fallopian tubes flushing methods, respectively. The average diameters of the ooplasm and oocyte were significantly varied in different reproductive stages as well as with ovulated oocytes (P<0.05). The average diameter of ooplasm and oocyte was 115.6 and 127.7, 143.0 and 162.0, 134.6 and 150.6, 159.6 and 185.6 for anestrus, follicular, luteal and ovulated oocytes, respectively. Highest number of oocytes with larger diameter could be collected from the follicular and luteal stages. In conclusion, the follicular and luteal ovaries are the best sources of oocytes for canine IVM.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.287-294
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• 2007

The present study was to conducted the sexing efficiency and accuracy of bovine embryo by LAMP (Loop-mediated isothermal amplification) method, the development of the biopsied embryos into re- reformation and the freezability of these blastocysts by slow-freezing and vitrification. In vivo embryos were superovaluted with gonadotropin(Antorin R-10) for 4 days combined with progestrone releasing intravaginal(CIDR) insertion in Hanwoo donors, and in vitro embryos were used blastocyst embryos at Day 7 or Day 8 after post-insemination in vitro. The biopsy of bovine embryo was carried out in a 80μl drop with Ca2+-Mg2+ free D-PBS and the viability of biopsied embryos were evaluated in IVMD medium at over 12 h culture time in 5% CO2 incubator.For embryo sexing, about five or seven blastomeres were isolated from in vitro and in vivo embryos at blastocysts with microblade. and were then subjected to LAMP. The survivability of biopsied embryos were no difference in the development rate to re-formation of blastocysts between in vivo and in vitro embryos(100% and 90% respectively). The rates of sexed embryos were compared according to two groups, the female rate was lower than that the male in the in vivo and in vitro embryos(46% vs, 54% and 40% vs, 60%, respectively). However, there were no difference in the overall sexing ratio between the two groups. The survivability of frozen-thawed sexed embryos were lower in the in vitro than in vivo embryos in the slow-freezing(Group 1) and vitrification method(Group 2), (41.7% vs. 58.8% and 57.1% vs, 77.8. respectively).

• Clinical and Experimental Reproductive Medicine
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• v.38 no.4
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• pp.193-202
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• 2011

Objective: We found previously that $interferon$ $regulatory$ factor ($Irf$)-1 is a germinal vesicle (GV)-selective gene that highly expressed in GV as compared to metaphase II oocytes. To our knowledge, the function of $Irf-1$ in oocytes has yet to be examined. The present study was conducted to determine the relationship between retinoic acid (RA) and RA-mediated expression of $Irf-1$ and the mouse oocyte maturation. Methods: Immature cumulus-oocyte-complexes (COCs) were collected from 17-day-old female mice and cultured $in$ $vitro$ for 16 hours in the presence of varying concentrations of RA (0-10 ${\mu}M$). Rate of oocyte maturation and activation was measured. Gene expression was measured by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) and cytokine secretion in the medium was measured by Bio-Plex analysis. Apoptosis was analyzed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Results: The rates of oocyte maturation to metaphase II and oocyte activation increased significantly with RA treatment (10 nM-1 ${\mu}M$). With 100 nM RA treatment, lowest level of $Irf-1$ mRNA and cumulus cell's apoptosis was found. Among 23 cytokines measured by Bio-Plex system, the substantial changes in secretion of tumor necrosis factor-${\alpha}$, macrophage inflammatory protein-$1{\beta}$, eotaxin and interleukin-12 (p40) from COCs in response to RA were detected. Conclusion: We concluded that the maturation of oocytes and $Irf-1$ expression are negatively correlated, and RA enhances the developmental competence of mouse immature oocytes $in$ $vitro$ by suppressing apoptosis of cumulus cells. Using a mouse model, results of the present study provide insights into improved culture conditions for $in$ $vitro$ oocyte maturation and relevant cytokine production and secretion in assisted reproductive technology.

• Korean Journal of Plant Tissue Culture
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• v.21 no.3
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• pp.157-160
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• 1994

Culture conditions for high Sequency somatic embryogenesis and plant regeneration in tissue cultures of sweet potato of two Korean cultivars 'Puyojaerae' and 'Yulmi' are described. Shoot apical meristem explants (height 150 $\mu\textrm{m}$; base: 350 $\mu\textrm{m}$) were cultured on MS medium supplemented with 1 mg/L 2,4-D. After 6 weeks of culture, greater than 80% of the survived explants produced embryogenic calli. When transferred onto MS medium with 0.1 mg/L each of 2,4-D and kinetin, the calli gave rise to somatic embryos at frequencies of 71% ('Puyojaerae') and 63% ('Yulmi'), respectively: When somatic embryos at various developmental stages measured in length were transversely cut into two halves and cultured on MS medium with 1 mg/L 2,L-D, the upper halves produced secondary embryos more frequently than the lower ones, and halves of somatic embryos less than 1 mm in length had a higher competence for secondary embryo formation than longer ones of either cultivar. However 'Puyojaerae' somatic embryo halves showed a higher frequency of secondary embryo formation than 'Yulmi' ones on the whole. Upon transfer onto MS basal medium, most of the primary and secondary somatic embryos underwent development into plantlets. The plantlets were transplanted to potting soil and grown to maturity in a phytotron. The overall results suggest that the shoot apical meristem culture system for somatic embryo formation in sweet potato previously established by us (SABRAOJ 21: 93-101) may be applicable regardless of it genotypes.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.9
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• pp.1420-1430
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• 2018

Objective: Epigallocatechin-3-gallate (EGCG) is a major ingredient of catechin polyphenols and is considered one of the most promising bioactive compounds in green tea because of its strong antioxidant properties. However, the protective role of EGCG in bovine oocyte in vitro maturation (IVM) has not been investigated. Therefore, we aimed to study the effects of EGCG on IVM of bovine oocytes. Methods: Bovine oocytes were treated with different concentrations of EGCG (0, 25, 50, 100, and $200{\mu}M$), and the nuclear and cytoplasmic maturation, cumulus cell expansion, intracellular reactive oxygen species (ROS) levels, total antioxidant capacity, the early apoptosis and the developmental competence of in vitro fertilized embryos were measured. The mRNA abundances of antioxidant genes (nuclear factor erythriod-2 related factor 2 [NRF2], superoxide dismutase 1 [SOD1], catalase [CAT], and glutathione peroxidase 4 [GPX4]) in matured bovine oocytes were also quantified. Results: Nuclear maturation which is characterized by first polar body extrusion, and cytoplasmic maturation characterized by peripheral and cortical distribution of cortical granules and homogeneous mitochondrial distribution were significantly improved in the $50{\mu}M$ EGCG-treated group compared with the control group. Adding $50{\mu}M$ EGCG to the maturation medium significantly increased the cumulus cell expansion index and upregulated the mRNA levels of cumulus cell expansion-related genes (hyaluronan synthase 2, tumor necrosis factor alpha induced protein 6, pentraxin 3, and prostaglandin 2). Both the intracellular ROS level and the early apoptotic rate of matured oocytes were significantly decreased in the $50{\mu}M$ EGCG group, and the total antioxidant ability was markedly enhanced. Additionally, both the cleavage and blastocyst rates were significantly higher in the $50{\mu}M$ EGCG-treated oocytes after in vitro fertilization than in the control oocytes. The mRNA abundance of NRF2, SOD1, CAT, and GPX4 were significantly increased in the $50{\mu}M$ EGCG-treated oocytes. Conclusion: In conclusion, $50{\mu}M$ EGCG can improve the bovine oocyte maturation, and the protective role of EGCG may be correlated with its antioxidative property.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.3
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• pp.334-339
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• 2007

Reactive oxygen species (ROS) generate during electrical activation of oocytes which has detrimental effects on embryo survival when overwhelmed. The present study was designed to investigate the ability of L-ascorbic acid, a novel water soluble antioxidant, to reduce the ROS level in developing embryos and their subsequent effects on embryo development in vitro. The compact cumulus oocyte complexes (COCs) were cultured in tissue culture medium (TCM)-199 supplemented with 10 ng/ml epidermal growth factor, 4 IU/ml pregnant mare serum gonadotropin (PMSG), and human chorionic gonadotropin (hCG) and 10% (v/v) porcine follicular fluid (pFF) for 44 h. After maturation culture, the denuded oocytes were activated with a single DC pulse of 2.0 kV/cm in 0.3 M mannitol solution containing 0.5 mM of HEPES, 0.1 mM of $CaCl_2$ and 0.1 mM of $MgCl_2$ for $30{\mu}s$ using a BTX Electro-cell Manipulator. The activated oocytes were cultured in modified North Carolina State University-23 (mNSCU-23) medium for 168 h. The level of $H_2O_2$ in each embryo was measured by the dichlorohydrofluorescein diacetate (DCHFDA) method at 48 h after activation. The blastocyst formation rate was significantly higher when culture medium was supplemented with 50 and $100{\mu}M$ L-ascorbic acid (31.2 and 38.7%, respectively) compared to non-supplemented (16.1%) group. Accordingly, significantly more cells in blastocyst were found for 50 and $100{\mu}M$ L-ascorbic acid (50.0 and 56.4, respectively) compared to 0 and $200{\mu}M$ L-ascorbic acid (36.5 and 39.8, respectively). L-ascorbic acid reduces the $H_2O_2$ level in developing embryos in a dose-dependant manner. The $H_2O_2$ level (pixels/ embryos) was 191.5, 141.0, 124.0 and 163.3 for 0, 50, 100 and $200{\mu}M$ L-ascorbic acid, respectively. So, we recommend to supplement 50 or $100{\mu}M$ L-ascorbic acid in porcine in vitro culture medium.

• School Mathematics
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• v.5 no.4
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• pp.421-440
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• 2003

It is difficult for the learner to understand completely the ratio concept which forms a basis of proportional reasoning. And proportional reasoning is, on the one hand, the capstone of children's elementary school arithmetic and, the other hand, it is the cornerstone of all that is to follow. But school mathematics has centered on the teachings of algorithm without dealing with its essence and meaning. The purpose of this study is to analyze the essence of ratio concept from multidimensional viewpoint. In addition, this study will show the direction for improvement of ratio concept. For this purpose, I tried to analyze the historical development of ratio concept. Most mathematicians today consider ratio as fraction and, in effect, identify ratios with what mathematicians called the denominations of ratios. But Euclid did not. In line with Euclid's theory, ratio should not have been represented in the same way as fraction, and proportion should not have been represented as equation, but in line with the other's theory they might be. The two theories of ratios were running alongside each other, but the differences between them were not always clearly stated. Ratio can be interpreted as a function of an ordered pair of numbers or magnitude values. A ratio is a numerical expression of how much there is of one quantity in relation to another quantity. So ratio can be interpreted as a binary vector which differentiates between the absolute aspect of a vector -its size- and the comparative aspect-its slope. Analysis on ratio concept shows that its basic structure implies 'proportionality' and it is formalized through transmission from the understanding of the invariance of internal ratio to the understanding of constancy of external ratio. In the study, a fittingness(or comparison) and a covariation were examined as the intuitive origins of proportion and proportional reasoning. These form the basis of the protoquantitative knowledge. The development of sequences of proportional reasoning was examined. The first attempts at quantifying the relationships are usually additive reasoning. Additive reasoning appears as a precursor to proportional reasoning. Preproportions are followed by logical proportions which refer to the understanding of the logical relationships between the four terms of a proportion. Even though developmental psychologists often speak of proportional reasoning as though it were a global ability, other psychologists insist that the evolution of proportional reasoning is characterized by a gradual increase in local competence.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.35-41
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• 1998

This study was carried out to investigate the development rates of human embryos co-cultured with cumulus cells to each blastocyst stage. Human zygotes were co-cultured on cumulus cell monolayer in YS medium supplemented with 20% hFF. On day 2, if patient had four or more "good" embryos (regular blastomeres without fragmentation), embryos were further cultured for 72hrs. Blastocysts on day 5 were classified into early blastocyst (ErB), early expanding blastocyst (EEB), middle expanding Blastocyst (MEB), and expanded blastocyst (EdB) on the basis of their morphological aspects of trophectoderm cells and blastocoele. Subsequently, maximum 3 of best blastocysts were transferred in 486 cycles. The results in this study were as follows: Patients who had four or more "good" embryos on day 2 were 498 persons, but patients whose embryos could not be transferred due to failure in development to the blastocyst stage on day 5 were 12 persons (2.4%). The development rate of embryos to the blastocyst stage was 58.2% (2,885/4,957) on day 5, and the rates that developed to the ErB, EEB, MEB, and EdB stage were 15.0% (743/4,957), 14.9% (739/4,957), 14.4% (714/ 4,957), and 13.9% (689/4,957), respectively. Total 1366 blastocysts were transferred in 486 cycles (mean number=2.81). The implantation rate and the ongoing implantation rate obtained by observing the number of G-sac and FHB were 29.9% (409/1,366) and 22.5% (308/1,366), respectively. The clinical pregnancy rate was 51.2% (249/486), and the ongoing pregnancy rate' was 39.1% (190/486). Among women showing ongoing pregnancy, women with singleton were 50% (95/190), women with twin were 37.9% (72/190), and women with triplet were 12.1% (23/190). Although triplet pregnancy rate in this study was high such as 12.1%, because many blastocysts with high viability were produced in our co-culture system using cumulus cells on day 5, we really believe that a multiple pregnancy except twin should not occur by selecting good embryos for maximum two blastocyst transfer. These results demonstrate that autologous cumulus cells may be used for the production of blastocysts with high developmental competence, and the use of autologous cumulus cells to be collected easily, and to be treated conveniently at OPU must be an effective means for obtaining high implantation and pregnancy rate.

• Korean Journal of Social Welfare
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• v.1
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• pp.51-71
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• 1979

During last five years several workshops and seminars among social work educators, in and out country, has taken place. In those gatherings there has been, criticism on American model on which curriculum of social work in Korea has mainly based, and many proposals which most developing countries should consider and adopt for developing their own curriculums. The proposals could be summarized as follows; 1. Specification of developmental functions of social work should be made so that the curriculum could involve. It also must come from own societal needs and own national development task. 2. Social work should participate and make contribution to plan and solve the main social problems in own countries. 3. Clarification of educational objective in undergraduate level should be made and one of them must be related to the first professional degree. 4. There should be the courses which provide the content of macro level participation. How much of the proposals are reflected in the current curriculum of Korea? What are the problems Korean social work education has been faced in connection with reflecting the proposals? What kinds of task we should or could perform in order to adopt the proposals? These are the questions which deserved to be studied. The followings are the answers to the questions; 1. The new courses such as social welfare policy and planning, Social Development, Population Dynamics and Family Planning, Social problems, Special Issues in Social Welfare, etc, are placed in the curriculum. 2. Though the new courses are added the courses of case work, group work, and community organization are strongly remained it means that integrative method is not quite adopted and that conflicts are taking place between new and old fashion. 3. Fieldwork placement policy has been changes from concurrent to block and from social work method oriented to social problem oriented. 4. There are lack of integration among the all courses, of consistency between pre and post courses and connection among the related courses. 5. Establishment of image of social worker with B, A. degree should be urgently taken place. It can't be done by social work field alone but by cooperation with all the forces related to the social work practice. 6. B. A. graduate should have a common base of knowledge and competence. It could be come from the clear and specified objectives of undergraduate level education. And agreement among the member schools on the objectives can call on the fundamental similarities in each curriculums. Different programs from one school to another can be tolerated as long as there are fundamental similarities among the schools. Basic concepts and framework of social work should be kept clearly. It is a slow and long process to make social work recognized as a profession in the developing countries. Korea can't be and exception. Failure of having social work be indegenous can't be the reason to refuse an change the basic concepts of social work. One of he most important task which social work education in Korea must achieve in the near future is to establish the minimum requirement courses in the curriculum. Social work field, on the other hand, must find the positions for the social works in the various settings and institute. Clear role and image of social worker can be obtained by doing that.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.4
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• pp.333-340
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• 2003

Objective: This study was performed to examine the maturation and the development to the blastocyst stage of immature oocytes collected from patients with high risk of ovarian hyperstimulation syndrome (OHSS). Materials and Methods: Cumulus-oocyte complexes (COCs) were collected following only HCGpriming for non stimulated IVF-ET cycles of the patients. At the time of oocyte collection, COCs were classified into three groups in accordance with their appearance (Group I: oocytes with dispersed cumulus cells; Group II: oocytes with compacted cumulus cells; Group III: oocytes with sparse cumulus cells). The in vitro maturation and blastocyst development rates of the COCs were compared among these groups. From August 2001 to June 2002, 48 IVM/IVF-ET cycles from 42 patients (mean age: $32.4{\pm}3.8$ years) were performed. To prevent the occurrence of OHSS, the patients were primed with 10, 000 IU HCG alone 36 h before oocyte collection without gonadotropin stimulation. Oocytes were aspirated on cycle days from 7 to 13. The normal COCs were classified into three groups according to their appearance. The aspirated immature oocytes were cultured in YS maturation medium containing 30% (v/v) human follicular fluid (HFF), 1 IU/ml FSH, 10 IU/ml HCG and 10 ng/ml rhEGF. Fertilization was induced by intracytoplasmic sperm injection (ICSI). All zygotes were co-cultured with cumulus cells in $10{\mu}l$ YS medium containing 10% HFF until day 7 after oocyte collection. Blastocyst transfer was performed on day 5 after ICSI. Results: Th e mean number of oocytes cultured in the IVM/IVF cycles was $24.7{\pm}10.6$. Of 1185 COCs, those assigned to Group I, II and III were 470 (39.7%), 414 (35.0%) and 301 (25.4%), respectively. The maturation rate (94.5%, 444/470, p<0.05) in Group I was significantly higher than those of Group II (62.8%, 260/414) and Group III (73.1%, 220/301). Especially, 30.9% of COCs in Group I (145/470) was matured on the day of oocyte aspiration. There were no differences in the rates of fertilization and cleavage among the three groups. The development rate to the blastocyst stage in Group I (54.6%, 206/377, p<0.05) was also significantly higher than those in Group II (33.0%, 68/206) and Group III (30.1%, 52/173). Twenty-four clinical pregnancies (50.0%) was obtained and 22 pregnancies (45.8%) are ongoing. Implantation rate in the present study was 24.6%. Conclusion: These results suggest that there is a positive correlation between the appearance of COCs and the developmental competence of the immature oocytes in non stimulated IVM/IVF cycles.