• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2000.11a
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• pp.27-33
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• 2000

• Journal of Embryo Transfer
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• v.9 no.3
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• pp.229-234
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• 1994

This experiment was carried out to develop the model system for mass production of biomedical and nutritional proteins (human proteins) through mamraary gland of the transgenic cattle produced by gene manipulation and embryological technologies. Human growth hormone gene fused with rat $\beta$-casein gene promoter was microinjected into pronuclei of one cell bovine embryos produced by in vitro fertilization. After microinjection, embryos were cultured in vitro for 6 or 7 days. Twenty embryos reaching to blastocysts were transferred to 10 beef recipients, each receiving two embryos. Recipients were diagnosed for pregnancy by rectal palpation at 76 days after embryo transfer. One of them was pregnant to term and produced a female calf weighing 21 kg at 280 days following embryo transfer. DNA was extracted from umbilical cord tissue and blood of calf born for confirming gene insertion. As determined by Southern hybridization, the transgene was not found.

• Clinical and Experimental Reproductive Medicine
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• v.38 no.1
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• pp.53-60
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• 2011

Objective: This study was carried out to compare the clinical outcome of elective single cleavage-embryo transfer (eSCET) to that of elective single blastocyst-embryo transfer (eSBET) in human IVF-ET. Methods: This study was a retrospective study which analyzed for 614 women who visited the Daegu Maria Clinic from August 2008 to December 2009. All were under 37 years old and had more than 8 mm of endometrial thickness on the day of hCG administration and at least one good quality embryo on day 3. The eSCETs were performed on day 3 (n=450) and the eSBETs were conducted on day 5 (n=164). Results: The numbers of retrieved oocytes, fertilized oocytes, and day 3 good quality embryos were significantly lower in the eSCET group (12.1${\pm}$6.0, 8.2${\pm}$4.6, and 4.2${\pm}$3.1, respectively) compared to the eSBET group (16.7${\pm}$7.2, 12.1${\pm}$5.0, and 8.5${\pm}$4.5, respectively; p<0.001). However, the clinical pregnancy, implantation, on-going pregnancy, and live birth rates of the eSCET group (46.7, 46.9, 40.0, and 36.7%, respectively) were not statistically different from those of the eSBET group (51.2, 51.8, 45.1, and 43.9%, respectively; p=0.318, 0.278, 0.254, and 0.103, respectively). Conclusion: These results suggested that elective single embryo transfer should be performed regardless of the developmental stage to women less than 37 years old who had more than 8 mm of endometrial thickness on the hCG administration day and at least one good quality embryo on day 3 in order to reduce the twin pregnancy rate without reducing the whole pregnancy rate.

• Journal of Embryo Transfer
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• v.30 no.4
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• pp.345-350
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• 2015

In the last 10 years, porcine somatic cell nuclear transfer to generate transgenic pig has been performed tremendous development with introduction and knockout of many genes. However, efficiency of porcine somatic cell nuclear transfer is still low and embryo transfer (ET) is one of important step for production efficiency. In porcine ET for production of transgenic cloned pig, we can consider many of points to increase production rates. In respect of seasonality and weather, porcine ET usually is not performed in summer and winter. Cloned transgenic embryos must be transferred into reproductive tracts of recipients where embryos are located after natural fertilization with similar estrous cycle. If cloned embryos with 2~4 cell stage are transferred, they must be transferred into oviducts in periovulatory stage. Number and deposition sites of transferred cloned embryos are important. And we must compare the methods of ET between surgical and non-surgical ones in respect of production efficiency. Sow recipients after natural estrus is most preferred recipients however its cost is must be considered. Here we will review many of current studies about porcine embryo transfer to increase production efficiency of transgenic pigs and strategies for further studies.

• Journal of Embryo Transfer
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• v.17 no.1
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• pp.33-44
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• 2002

These studies were carried out to establish an effective in vivo embryo transfer methods in Hanwoo by analyzing several factors that influence this process. In an embryo transfer, recipients with grade A corpus luteum of the right ovary and that of grade B of the left one showed a higher pregnancy rate(p<0.1) than others. The pregnancy rates of frozen embryos were significantly lower(P<0.01) than those of fresh ones; the former resulting in 35% and the latter resulting in 56.2%. Transfer of embryos according to the estrus cycle(6.0 ∼ 9.0 days) did not show a significant difference in pregnancy rate with fresh embryos recording 45.4 ∼65.7% and frozen ones recording 22.0 ∼ 50.0%. According to the status of corpus luteum and embryo freezing or not, the pregnancy rate was higher on grade A corpus luteum with 40.8 ∼67.9% than B and C which ranged from 25.0∼56.0%. The results of embryo transfer according to the development stage and grade of embryos showed that regardless of the embryo's grade. transfer of morula recorded an average pregnancy rate of 46.3%. This results higher than the transfer of blastocyst which was 34.1%.

• Journal of Embryo Transfer
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• v.6 no.2
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• pp.1-17
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• 1991

It is widely recognized that the embryonic or fetal loss after breeding is common in the cattle and that it is an important factor affecting reproductive efficiency. The causes of this loss have been subject of extensive researches and the results indicate that the embryonic mortality may he primary factor responsible for low pregnancy rates in non-embryo transfer bovine populations as well as embryo transfer programs. However, it's causes are still not clearly understood. The embryonic mortality or pregnancy rate has been influenced by various embryonic and maternal effects related to genetic and environmental factors. The timing and extent of embryonic mortality vanes greatly according to authors and estimating methods, because it is difficult to make direct measurements. The major important factors that may influence the embryonic losses or pregnancy rates after embryo transfer can be summeirized. 1.When an embryo is transferred to unmated recipients, the contralateral transfer to corpus luteum results in a lower survival rate than ipsilateral deposition. When the embryos are transferred for the production of twin calves, their survivals and twin pregnancies have quite inconsistent according to the transfer methods either to the unmated-synchronized or already mated recipients and more works are needed to accurrately clarify the previous results. 2.Although embryos can be cultured in vitro some hours without the great declines in pregnancy rates, the rates differ markedly among culture times and media but may be improved by co-transfer systems. 3.Embryo developmental stages and quality grades clearly affect the survival rate following freezing and the pregnancy rate after transfer and the selection of embryos without chromosome abnormalities and of high fertile semen may also be considered to increase the pregnancy rates. 4.Many researches have attempted to relate the plasma progesterone levels to pregnancy rates and others have done either direct progesterone supplementation or luteal stimulation by hCG treatment in order to increase the pregnancy rates. However, these effects on pregnancy rates are inconsistent and also contradictory. 5.The asynchrony between donors or embryos and recipients may he a major cause of embryo death and low pregnancy rate and the sensitivity to uterine asynchyony differs in according to the quality and stages of embryos. 6.The extremes of poor or over nutrition during early pregnancy in the recipients are detrimental to the survival of embryos and the good body condition is required to prevent a reduejion of pregnancy rates. The uterine pathogens in embryonic mortality or fertility have been questioned but the infection of C.pyogenes and Campylobacter fetus is still important pathogens. 7.The heat stress during early pregnancy may reduce conceptus weight and possibly increase the embryonic mortality.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 1997.05a
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• pp.16-17
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• 1997

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 1997.05a
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• pp.1-8
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• 1997

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 1997.05a
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• pp.18-26
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• 1997

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2001.05a
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• pp.7-8
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• 2001