• Toxicological Research
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• v.35 no.4
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• pp.343-351
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• 2019

Many in vitro developmental toxicity assays have been proposed over several decades. Since the late 1980s, we have made intermittent attempts to introduce in vitro assays as screening tests for developmental toxicity of inhouse candidate products. Two cell-based assays which were developed two decades apart were intensively studied. One was an assay of inhibitory effects on mouse ascites tumor cell attachment to a concanavalin A-coated plastic sheet surface (MOT assay), which we studied in the early days of assay development. The other was an assay of inhibitory effects on the differentiation of mouse embryonic stem cell to beating heart cells (EST assay), which we assessed more recently. We evaluated the suitability of the assays for screening in-house candidates. The concordance rates with in vivo developmental toxicity were at the 60% level. The EST assay classified chemicals that inhibited cell proliferation as embryo-toxic. Both assays had a significant false positive rate. The assays were generally considered unsuitable for screening the developmental toxicity of our candidate compounds. Recent test systems adopt advanced technologies. Despite such evolution of materials and methods, the concordance rates of the EST and MOT systems were similar. This may suggest that the fundamental predictivity of in vitro developmental toxicity assays has remained basically unchanged for decades. To improve their predictivity, in vitro developmental toxicity assays should be strictly based on elucidated pathogenetic mechanisms of developmental toxicity.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.157-164
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• 2014

PURPOSE. This study focused on in vitro cell differentiation and surface characteristics in a magnesium coated titanium surface implanted on using a plasma ion source. MATERIALS AND METHODS. 40 commercially made pure titanium discs were prepared to produce Ti oxide machined surface (M) and Mg-incorporated Ti oxide machined surface (MM). Surface properties were analyzed using a scanning electron microscopy (SEM). On each surface, alkaline phosphatase (ALP) activity, alizarin red S staining for mineralization of MC3T3-E1 cells, and quantitative analysis of osteoblastic gene expression, were evaluated. Actin ring formation assay and gene expression analysis of TRAP and GAPDH performing RT-PCR were performed to characterize osteoclast differentiation on mouse bone marrow-derived macrophages (BMMs). RESULTS. MM showed similar surface morphology and surface roughness with M, but was slightly smoother after ion implantation at the micron scale. M was more hydrophobic than MM. No significant difference between surfaces on ALP activity at 7 and 14 days were observed. Real-time PCR analyses showed similar levels of mRNA expression of the osteoblast phenotype genes; osteopontin (OPN), osteocalcin (OCN), bone sialoprotein (BSP), and collagen 1 (Col 1) in cell grown on MM at 7, 14 and 21 days. Alizarin red S staining at 21 days showed no significant difference. BMMs differentiation increased in M and MM. Actin ring formation assay and gene expression analysis of TRAP showed osteoclast differentiation to be more active on MM. CONCLUSION. Both M and MM have a good effect on osteoblastic cell differentiation, but MM may speed the bone remodeling process by activating on osteoclast differentiation.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.4
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• pp.166-172
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• 2019

Objective: In vitro maturation (IVM) of immature oocytes can be useful for some infertile patients. In IVM programs, the rates of embryo formation and pregnancy are low. Therefore, it is essential to recognize the main factors involved in regulating oocyte maturation in vitro. The purpose of this study was to investigate the effects of growth differentiation factor 9 (GDF9) and cumulus cell (CC) supplementation in IVM medium on the rates of embryo formation and viability of human blastocysts. Methods: A total of 80 germinal vesicle oocytes from stimulated cycles underwent an IVM program. The oocytes were divided into four groups, where group I consisted of IVM media only and served as the control, group II consisted of IVM+CCs, group III consisted of IVM+GDF9 (200 ng/mL), and group IV consisted of IVM+CCs+GDF9 (200 ng/mL). Intracytoplasmic sperm injection was performed on the IVM oocytes, and the cleavage embryos that were generated were vitrified. Following thawing, the embryos were cultured for 3 additional days, and the viability rates of the developed blastocysts were determined. Results: The maturation rate of the oocytes did not differ significantly across the four groups. The fertilization rate in group II was significantly higher than that in the control group (76.5% vs. 46.2%). Embryo formation was significantly more frequent in all experimental groups than in the control group, while blastocyst formation did not show significant differences in the three experimental groups compared to the control. The mean viability rates in groups II, III, and IV were 58.16%, 55.91%, and 55.95%, respectively, versus 37.78% in the control group (p< 0.05). Conclusion: Supplementation of IVM culture media with GDF9 and CCs enhanced the fertilization, embryo formation, and viability rates of blastocysts generated from vitrified cleavage embryos.

• Journal of Life Science
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• v.25 no.2
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• pp.223-230
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• 2015

Regulator of calcineurin 1 (RCAN1) is an endogenous calcineurin inhibitor that plays an important role in the pathogenesis of diseases related to the calcineurin-NFATc1 signaling pathway. The RCAN1-4 isoform is subject to NFATc1-dependent regulation. During receptor activator of nuclear factor kappa-B ligand (RANKL)-stimulated osteoclastogenesis, the calcineurin-NFATc1 pathway is critical. Because there is little information available on the role of RCAN1 in osteoclast differentiation, this study investigated whether changes in RCAN1 expression are related to the calcineurin-NFATc1 pathway and osteoclast differentiation. Mouse bone marrow monocytes (BMMs) were treated with 50 ng/ml of RANKL and M-CSF. Expression levels of NFATc1, calcineurin, and RCAN1 isoforms were determined using RT-PCR and Western blotting. Osteoclast differentiation was examined using tartrate-resistent acid phosphatase (TRAP) staining. To evaluate the effect of RCAN1 overexpression on osteoclastogenesis, cells were transfected with a mouse RCAN1-4 cDNA plasmid. After RANKL stimulation of BMMs, expression of NFATc1 and RCAN1 was increased at the mRNA and protein level, while calcineurin expression was unchanged. When the RCAN1-4 gene construct was transfected, the expression of RCAN1 protein was not increased despite several-fold increases in RCAN1-4 mRNA expression. Regardless of RANKL stimulation, over-expression of RCAN1-4 tended to reduce NFATc1 expression and knock-down of RCAN1 increase it. While BMMs transfected with the RCAN1-4 vector were differentiated into distinct osteoclasts, their phenotypes did not vary from those of mock controls. These results suggest that RCAN1 has a limited effect on the calcineurin-NFATc1 pathway during RANKL-stimulated osteoclast differentiation.

• 대한치주과학회:학술대회논문집
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• 2004.11a
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• pp.153-154
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• 2004

• 대한생식의학회:학술대회논문집
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• 2004.06a
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• pp.73-74
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• 2004

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.18-33
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• 2002

• 대한생식의학회:학술대회논문집
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• 2001.11a
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• pp.114-114
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• 2001

• 대한생식의학회:학술대회논문집
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• 2002.11a
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• pp.104.2-105
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• 2002

• 대한생식의학회:학술대회논문집
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• 2002.05a
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• pp.74.2-75
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• 2002