• Clinical and Experimental Reproductive Medicine
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• v.24 no.1
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• pp.101-109
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• 1997

This study was carried to determine the possibility of finding motile spermatozoa and fertilization, pregnancy rate after testicular sperm extraction(TESE) with ICSI in obstructive and non-obstructive azoospermic patients. In 154 cases(132 patients), obstructive azoospermia was 77 cases and non-obstructive azoospermia was 77 cases. In obstructive azoospermia, patients generally showed normal spermatogenesis and included vas agenesis(n=8), multiple vas obstruction(n=7), epididymal obstruction (n=54). Total of 982 retrieved oocytes were obtained and 84.4% were injected. The fertilization rates with 2 PN and cleavage rate were 72.5% and 62.3%, respectively. 30 pregnancies(38.9%) were achieved and the ongoing pregnancies were 22 cases (28.6%). In non-obstructive azoospermia, patients showed hypospermatogenesis(n=49), maturation arrest(n=4), Sertoli cell only syndrome (n=24). The various stages of spermatogenic cell could be retrieved by TESE and could be reached normal fertilization and embryo development with ICSI. Total of 1072 retrieved oocytes obtained and 80.2% were injected. The fertilization rates with 2 PN and cleavage rate were 52.8% and 68.9%, respectively. 22 pregnancies(30.1%) were achieved and the ongoing pregnancies were 19 cases(26.0%). Conclusively, the combination of TESE with ICSI using testicular spermatozoa can achieve normal fertilization and pregnancy rate and effective method in obstructive and non-obstructive azoospermic patients.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.1
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• pp.111-118
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• 1997

Intracytoplasmic sperm injection (ICSI) recently has been utilized widely as the most successful technique to overcome the unfertilization problem in cases of severe male infertility in couples who could not be treated by conventional IVF. Recently, indications of ICSI have been extended further and more fertilized oocytes become available. Thus, it is necessary to examine the efficiency of freezing the surplus embryos obtained from ICSI. We compared the survival rate and the future outcome of cryopreserved embryos obtained either after conventional IVF or ICSI during the same period. After ICSI or IVF, five best-quality embryos from each patient were transferred in the stimulation cycle and the surplus pronuclear (PN) stage oocytes or multicellular embryos were cryopreserved by slow freezing protocol with 1,2-propanediol (PROH) as a cryoprotectant. A total of 792 embryos from ICSI trial were thawed and 65.2% (516/792) survived. The survival rates of PN stage oocyte, multicellular embryo and PN + multicellular embryo were 63.5%, 68.2%, 64.0%, respectively. After 111 transfers, 34 pregnancies were achieved, corresponding to a clinical pregnancy rate of 30.6% per transfers. We thawed 1033 embryos from IVF trials and 57.5% (594/1033) survived. In IVF cycle, the survival rates of PN stage oocyte, multicellular embryo and PN + multicellular embryo were 58.2%, 65.2%, 40.2%, respectively. Thirty eight clinical pregnancies were established after 134 transfers, corresponding to a pregnancy rate of 28.4% per transfer. The cleavage rate of thawed PN stage oocytes from ICSI trial (61.3%) was significantly higher than those from conventional IVF (53.4%). The developmental rates of good embryo (${\geqq}$ grade II) in thawed PN stage oocytes obtained from conventional IVF and ICSI were 63% and 65%, respectively. We concluded that PN stage oocytes, multicellular embryos resulting from ICSI procedure can be successfully frozen/thawed with reasonable clinical pregnancy rates comparable to those of IVF.

• Journal of the Economic Geographical Society of Korea
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• v.1 no.1
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• pp.151-172
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• 1998

Over the past two decades, the process of globalization of multinational corporations has increased at a rapid rate. One manifestation of this process is the establishment of corporate head offices in a variety of international centers to administer and coordinate, the day-to-day operations in the host countries. In establishing a subsidiary overseas a firm creates a direct link between the operations of the domestic corporate center and the foreign host center This paper investigates elements of stability and change in the international linkage patterns among domestic parent corporations and host subsidiaries over the past several decades. In particular, it seeks answers to a number of question related to stability and change in linkages among foreign centers of control and those Canadian centers selected to administer the subsidiary operations from 1970 to 1991 over the four primary sectors, namely, resources, manufacturing, services, and finance. By confirming the core stability and dispersed linkages hypotheses, the papar offers some generalizations with respect to the location and stability of subsidiary headquarters centers in Canada and their respective subsector specialties. Finally, it addresses further research avenues fer the quaternary place study.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.3
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• pp.311-318
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• 1997

Bypassing acrosome reaction and fusion process in intracytoplasmic sperm injection(ICSI), most of injected spermatozoa still contain intact acrosome contents and plasma membrane. It Is not known yet what acrosome contents and plasma membrane of spermatozoa have effect on the development of embryo. For further understanding of fertilization process after ICSI, we studied the time of pronucleus formation, disappearance and first cleavage in human zygote, and pregnancy rate in relation to acrosome reaction rate of spermatozoa after ICSI. Seventy cycles undergoing ICSI program were randomly selected. Sperm suspension from 38 cycles were treated 50% human follicular fluid(hFF) for 3 hours in order to induce acrosome reaction, others were not treated as control. Acrosome reaction in hFF treated and non-treated group was assessed by fluorescein isothiocyanate(FITC)-conjugated Arachis hypogea(PNA) and Pisum sativum agglutinin(PSA). Oocytes were classified into 'good' and 'poor' according to their morphology. After ICSI, fertilization of oocytes were assessed by detection of two pronuclei at 16 hours. The pronuclei disappearance and first cleavage of zygotes were observed at 24 hours, and then embryos were transferred to uterus after culture for 72 hours. The rate of acrosome reaction of spermatozoa in hFF treated group was significantly higher than that in control(p<0.01). Fertilization rates of good oocytes were not different both control and hFF treated group(81.3%(174/206) vs. 72.1%(102/130)). But, in poor oocytes, the fertilization rates in hFF treated group(72.1%(149/183)) were increased compared than those of control group (63.6%(98/140), p<0.01). In either good or poor oocytes, the rates of pronuclei disappearance in hFF treated-spermatozoa injected oocytes were higher than control (59.1%(103/174), 56.4%(84/149) vs. 32.4%(33/102), 37.8%(37/98), p<0.01). Also, the rates of thirst cleavage were increased in hFF treated group (31%(54/174), 24.1%(36/149)) compared than those of control group (10.8%(11/102), 13.2%(13/98), p<0.01). The pregnancy rates of hFF treated group (42.1%(16/38)) were slightly higher than control group (28.1%(9/32), p>0.05). But, the pregnancy rate of group which possessed more than one cleavaged zygote at 24 hours was higher than group which did not (45.2%(19/42) vs. 21.4%(6/28), p<0.05). From these results, the development of zygotes were faster in higher acrosome reacted sperm group than lower acrosome reacted sperm group after ICSI. Our results may be explained that acrosomal membrane and plasma membrane are easily detached from spermatozoa in acrosome reacted spermatozoa compared with acrosome intact sperm in the cytoplasm of oocyte during pronuclear formation. We conclude that the injection of acrosome reacted spermatozoa will increase the pregnancy rate as they can induce fast embryonic development in ICSI.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.4
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• pp.237-243
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• 2006

Objective: The aim of this study was to evaluate the efficacy of frozen-thawed ET in poor prognosis patients such as the old age (38~44 years; OA group) and the patients who did not achieve clinical pregnancy with the first fresh ET cycle (non-pregnant patients; NP group). Methods: Laboratory and clinical data were collected from fresh and frozen-thawed ET cycles of OA and NP group. Controlled ovarian hyperstimulation (COH) and conventional insemination or ICSI, in vitro culture and ET were performed by routine procedures. Supernumerary embryos were frozen by the slow freezing method, and frozen embryos were thawed by the rapid thawing method. Embryo development, pregnancy and implantation rates were statistically analyzed by Student t-test and chi square test Results: Mean ages were similar between fresh ET ($40.0{\pm}1.8$ years, n=206) and frozen-thawed ET ($39.9{\pm}1.9$ years, n=69) cycles in OA group. However, the clinical pregnancy and implantation rate of subsequent frozen-thawed ET significantly higher than those of fresh ET cycles (29.0% and 11.2% vs. 16.5% and 7.0%, p<0.05). In NP group, there was no difference in the mean age between fresh ET ($31.2{\pm}2.3$ years, n=40) and frozen-thawed ET ($31.9{\pm}3.1$ years, n=119) in subsequent cycles. The clinical pregnancy and implantation rates were similar between the subsequent fresh ET (42.5% and 22.6%) and the frozen-thawed ET (40.3% and 18.8%). Conclusion: In old age patients, higher pregnancy rate of frozen-thawed ET compared to fresh ET cycles in this study. It may be related that better uterine environments for implantation in frozen-thawed ET cycles than that of non-physiological hormonal condition in uterus of fresh COH cycles.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.323-329
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• 1998

The safety of ICSI as a novel procedure of assisted fertilization may be assessed by the health of the baby born. In order to evaluate the safety of ICSI, perinatal outcome and congenital anomaly of the babies born after ICSI were compared with those of babies born after IVF (control group). We analysed the clinical data from the obstetric and pediatric records, including the information obtained through telephone. The results are as follows; Mean gestational age $({\pm}SEM)$ and birth weight in singleton pregnancy were $38.8{\pm}1.9$ weeks and $3209.7{\pm}501.9gm$ in IVF group, $39.0{\pm}2.2$ weeks and $3289.9{\pm}479.5gm$ in ICSI group, respectively. Mean gestational age and birth weight in twins were $36.8{\pm}2.1$ weeks and $2512.8{\pm}468.0gm$ in IVF group, $36.5{\pm}2.8$ weeks and $2492.7{\pm}537.1gm$ in ICSI group. In IVF group, perinatal mortality rates were 8.5 in singletons and 56.6 in twins; for the ICSI singletons and ICSI twins, the perinatal mortality rates were 11.6 and 49.0, respectively. The incidence of congenital malformations was 3.6% (8/224) in IVF group and 2.1% (4/188) in ICSI group, there was no statistical difference (p>0.05, Fisher's exact test). The incidence of major congenital anomalies was 0.9% (2/224; pulmonary artery hypoplasia, renal cystic dysplasia) in IVF group and 1.1% (2/188; holoprosencephaly, Cri du chat syndrome) in ICSI groups (p>0.05, Fisher's exact test). Similarly, there was no significant difference in incidence of minor congenital anormalies 2.7% (6/224) in IVF group and 1.1% (2/188) in ICSI group respectively (p>0.05, Fisher's exact test). In conclusion, there was no difference in the perinatal outcome and the incidence of congenital anomalies between the babies born after ICSI and those after conventional IVF.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.4
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• pp.329-338
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• 2010

Objective: This study was carried out to know whether cryopreservation of sibling 2PN zygotes could increase the cumulative delivery rates in the patients who had less than 10 fertilized zygotes. Methods: A retrospective analysis was performed in 138 in vitro fertilization-embryo transfer (IVF-ET) cycles with less than 10 fertilized zygotes during January 2003 to December 2007 in Cheil General Hospital. These cycles were divided into two groups. In Group I (n=86), all fertilized embryos were cultured to transfer on day 3 without cryopreserved embryos at the 2PN stage. In Group II (n=52), among fertilized zygotes, some sibling zygotes were frozen at the 2PN stage, the remainder were cultured to transfer. Clinical outcomes in fresh ET cycles and cumulative ongoing pregnancy rates after subsequent frozen-thawed (FT)-ET cycles were compared. Results: There were no significant differences in female mean age, number of retrieved oocytes and total fertilized embryos between two groups, Number of cultured embryos was significantly lower in Group II ($5.2{\pm}0.5$) than in Group I ($8.4{\pm}0.7$) (p<0.01). Also, number of transferred embryos was significantly lower in Group II ($3.3{\pm}0.6$) compared with Group I ($3.6{\pm}0.6$) (p<0.01). ${\beta}$-hCG positive rates and delivery rates (51.2 vs. 46.2 % and 41.9 vs. 34.6 %, respectively) after fresh ET were slightly higher in Group I than in Group II. However, the differences were not statistically significant. Also, the cumulative delivery rates after subsequent FT-ET cycles were not significantly different between Group I (48.8%) and Group II (50.0%). Conclusion: This study showed that cryopreservation of sibling 2PN zygotes from patients who had less than 10 zygotes in the fresh ET cycles did not increase cumulative delivery outcomes. But, it could provide an alternative choice for patients due to offering more chance for embryo transfers if pregnancy was failed in fresh IVF-ET cycles.