• The Korean Journal of Zoology
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• v.15 no.1
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• pp.25-33
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• 1972

Two-Cell mouse embryos were incubated in the anterior chamber of the rat eye, which has been known as the best place among other animals' for the mouse ovum maturation, in order to observe the capability of their early development. Within 120 hours after incubation, 71.0% of two-cell embryos have developed to the blastocysts in the male rat eye, while only 38.5% in the eye of the same mouse as donated two-cell embryos. Thus, the rat eye chamber provides more favourable environment to the embryos than the mouse itself. The results are consistent with those of the previous studies comparing the maturation of the mouse follicular oocytes in the mouse and the rat eye chamber. Although the aqueous humor which is filled in the anterior chamber of the eye is characterized by its specific properties, being of higher osmolarity, higher concentrations of ascorbic acid, pyruvate and lactate, but lower of proteins and lower temperature than those in blood or lymph serum, The embryos are able to under-take their cleavage as normal as in vivo or in vitro. Concerning with a number of studies in vitro on the development of the mouse embryos which are requiring a very limited condition, the fact that they are able to manage their further development under very different enviroment from our knowledges would provide us a moment to understand their behavior during the early development. The difference of the proportion of the developed blastocysts between in the mouse eye chamber and in the rat can possibly be resulted from the species specific difference in the physicochemical properties between their eye chambers. This assumption is based upon the findings by many investigators who chmpared the nature of the eye chamber of various animals. As a consequence, the rat eye chamber might consist of better properties for the embryonal growth than the mouse eye chamber. The mouse embryos cleaved with a delayed period. In normal development they complete almost the cleavage within 94 hours after fertilization. However, in the present studies, 81.1% of two-cell embryos developed to the blastocysts and the morula in 120 hours in the eye chamber, assumed to be about 154 hours after fertilization. Such delay in development would be caused mainly by the low temperature of the eye chamber. At present we can make two assumptions to explain the capability of the emtryonal development in the eye chambers. One is that the embryos would possess an ability to adapt themselves to the environment which provides unfavourable conditions. The other is that the embryos might remain for a certain duration in the eye chamber, which is filled with a new body fluid produced immediately after the loss of the aqueous humor and the fluid of which becomes similar to blood serum in component. The first assumption is highly reliable since the embryonal cells are mostly at the undifferentiated state and so they probably engage a simple metabolism during their early period. The second assumption is induced by the fact that the rabbit eye chamber produces a plasmoid humor which has mostly similar components to blood serum after loss of aqueous humor through cornea by puncturing. However, the plasmoid humor is substituted by the initial aqueous humor in eight hours. Even though this finding, production of the new fluid, could be applied to the rat eye, it is hardly reliabel that the plasmoid humor remains for such a long period as 120 hours. Consequently, the development of the embryos is more likely due to their adaptability to the new environment during their early developmental stages.

• Biomolecules & Therapeutics
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• v.2 no.1
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• pp.82-93
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• 1994

DA-125, a new anthracycline antitumor antibiotic, was at dose levels of 0, 0.1, 0.3 and 1.0 mg/kg/day administered intravenously to pregnant Sprague-Dawley rats during the organogenetic period. Two-third of dams per group were subjected to caesarean section on day 20 of pregnancy and the remaining 10 dams per group were allowed to deliver. Effects of test substance on dams, embryonal development of Fl fetuses, as well as growth, behaviour and mating performance of Fl offspring were examined. 1. At 1 mg/kg, one out of the 10 dams showed difficult delivery. A decrease in food consumption, a loss in body weight and a decrease of spleen weight were found in this dose level group. At 0.3 mg/kg, difficult deliverys were observed in two out of the 10 dams. 2. At 1 mg/kg, an increased resorption rate and a decreased fetal weight were found. In addition, various types of external, visceral and skeletal malformations occurred at an incidence of 11.9, 41.8 and 14.5%, respectively. 3. At 1 mg/kg, body weight reduction, small eyeball, hydrocephalus and atrophy of sexual organs were observed in Fl offspring. One male pup receiving 0.3 mg/kg died on day 2 of lactation. The results show that the no-effect dose levels (NOELs) for dams and Fl offspring are 0.1 mg/kg/day and NOEL for Fl fetuses is 0.3 mg/kg/day.

• Clinical and Experimental Reproductive Medicine
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• v.1 no.1
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• pp.49-54
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• 1974

In the present studies, effect of progesterone on the germinal vesicle break-down of the mouse oocytes cultured in the micro tube was investigated. The results obtained are as follows: As dose of progesterone in the medium rose, accordingly the break-down of the germinal vesicle was suppressed. It was found that $ED_{50}$ was 15.7 ${\mu}g$/ml, and $ED_{90}$ 60.7 ${\mu}g$/ml of progesterone. The dose suppressing the oocyte maturation was apparently higher than that on the rabbit or on the mouse embryonal development. The inhibiting effect of progesterone on the GVBD was reversible. The germinal vesicle of the oocytes were broken down immediately in the medium upon removal of the hormone. Progesterone stops meiosis at any stage upon administration, while dbe AMP or theophylline supresses only the break-down of the nuclear membrane. Recovering of the meiotic division of the oocytes once exposed to progesterone was delayed a little. The inhibiting action of progesterone was not altered by adding more pyruvate or in the presence of higher concentration of the mineral ions in the culture medium.

• Animal Bioscience
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• v.34 no.4
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• pp.533-538
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• 2021

Objective: Pluripotent stem cell-derived lymphatic endothelial cells (LECs) show great promise in their therapeutic application in the field of regenerative medicine related to lymphatic vessels. We tested the approach of forced differentiation of mouse embryonal stem cells into LECs using biodegradable poly lactic-co-glycolic acid (PLGA) nanospheres in conjugation with growth factors (vascular endothelial growth factors [VEGF-A and VEGF-C]). Methods: We evaluated the practical use of heparin-conjugated PLGA nanoparticles (molecular weight ~15,000) in conjugation with VEGF-A/C, embryoid body (EB) formation, and LEC differentiation using immunofluorescence staining followed by quantification and quantitative real-time polymerase chain reaction analysis. Results: We showed that formation and differentiation of EB with VEGF-A/C-conjugated PLGA nanospheres, compared to direct supplementation of VEGF-A/C to the EB differentiation media, greatly improved yield of LYVE1(+) LECs. Our analyses revealed that the enhanced potential of LEC differentiation using VEGF-A/C-conjugated PLGA nanospheres was mediated by elevation of expression of the genes that are important for lymphatic vessel formation. Conclusion: Together, we not only established an improved protocol for LEC differentiation using PLGA nanospheres but also provided a platform technology for the mechanistic study of LEC development in mammals.

• Journal of Korean Society of Forest Science
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• v.85 no.4
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• pp.667-679
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• 1996

Clonal forestry and reforestation programmes are especially interested now in development and application of controllable biotechnological systems based on the production of conifer somatic embryos in bioreactors with their following drilling and/or storage in the form of "artificial seeds". Modern achievements in conifer somatic embryogenesis has guided the development not only of biotechnological systems in forestry, but also of basic research in conifer embryology, cell and molecular biology. At the present time, the level of development of applied research on conifer somatic embryogenesis is well ahead our understanding of this complex phenomenon. The "bottleneck" situation in relation between basic and applied sciences will eventually lead to the appearance of "weak points" in biotechnological systems. In the present review, the major advances and the most pressing problems in the application of conifer somatic embryogenesis both to forest biotechnology and to basic research are in the focus of attention.

• Clinical and Experimental Reproductive Medicine
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• v.1 no.1
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• pp.43-48
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• 1974

생쥐(C3H/JMS)의 한쪽 자궁(子宮)에 봉합계(縫合系)를 삽입한 후 초기배아(初期胚兒)의 발생과정(發生過程), 이동속도(移動速度) 그리고 착상(着床)의 상태를 관찰하였다. 임신한지 2일째 되는 날에 자궁(子宮)에 장치를 받지 않은 쪽에서는 초기배(初期胚)의 일부가 이미 수난정(輸卵精)의 뒷부분에 도달하고 있었으나 장치를 받은 쪽에서는 아직도 수난정(輸卵精) 중부(中部)에 머물러 있었다. 3일째가 되면 대조(對照)가 되는 바른쪽 자궁(子宮)에서는 $8{\sim}16$세포기에 드는 배아(胚兒)가 79%에 이르며 24%는 이미 자궁(子宮)에까지 도달하고 있으나 장치를 한 쪽에서는 $8{\sim}16$세포기의 배아(胚兒)가 69%가 되며 겨우 8.2%만이 자궁(子宮)에 이르고 있다. 4일째가 되면 대조자궁(對照子宮)에서는 전체 배아(胚兒)의 75%가 그리고 장치 자궁(子宮)에서는 61%가 상실배(桑實胚)를 이루며 전자(前者)에서 60%, 후자(後者)에서는 40%가 자궁(子宮)내에 진입하게 된다. 정상적(正常的)인 생쥐에서는 임신 4일이 되면 거의가 배낭기(胚囊期)에 이르는 것으로 알려져 있으나 한쪽 자궁(子宮)에 실을 장치한 생쥐에서는 대조자궁(對照子宮)이거나 장치 자궁(子宮)이거나 모두 배낭(胚囊)의 형성(形成)이 늦어지고 있다. 한 자궁(子宮)당 발견되는 정상배(正常胚)의 평균치(平均値)는 대조구(對照區)에서 6.3정도로 임신 2일에서 4일 사이에 큰 차이가 없으나 처리구(處理區)에서는 2일에서 4일 사이에 6.5에서 3.8로 감소한다. 이상배(異常胚)는 대조구(對照區)에서 2일째에 2.2였던 것이 0.4로 크게 줄지만 처리구(處理區)에서는 대조구(對照區)에서 처럼 급격한 감소를 볼 수 없다. 임신한지 17일 되는 날 대조구(對照區)에서 15개의 자궁(子宮)가운데 한지 2개의 자궁(子宮)만이 착상(着床)흔적을 보였지만 처리구(處理區)에서는 전혀 착상(着床)되었던 흔적을 볼 수 없었다. 결국 생쥐에서는 한 쪽 자궁(子宮)에 이물질(異物質)을 삽입했을 때 장치를 받은 자궁(子宮)뿐 아니라 다른 한 쪽 자궁(子宮)에서도 착상(着床)이 일어나지 않을 뿐 아니라 이상난자(異常卵子)의 발생(發生)을 증가시키며 배아(胚兒)의 난할속도(卵割速度)가 늦어지고 또 배아(胚兒)의 이동(移動)이 늦어진다는 것을 알게 되었다.