• Journal of Radiation Protection and Research
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• 제18권2호
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• pp.37-45
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• 1993

생물학적 선량평가를 위한 생화학적 지표 연구로서 흰쥐 혈액 내 효소활성도의 변화를 조사한 결과는 다음과 같다. 1) Alkaline phosphatase 활성도는 0.1, 0.25, 0.5, 2, 4Gy의 방사선 조사후 24시간까지 혈액내 활성도가 증가하였고 72시간 경과시에는 대조군과 비슷한 활성도를 보였다. Creatine kinase는 2, 4Gy 방사선 조사후 혈액내에서 활성도가 72시간까지 증가하였으나 0.1, 0.25Gy 방사선 조사시에는 커다란 변화를 보이지 않았다. 2) Malate dehydrogenase 활성도는 0.1, 025, 0.5Gy 방사선 조사시에는 커다란 변화가 없었으며 lactate dehydrogenase는 방사선 조사후 활성도가 감소하였다. 3) GOT의 활성도는 선량률 0.1Gy/min.로 0.1, 0.25, 0.5, 2, 4Gy 조사후에는 어떠한 변화도 없었으며 선량률 0.5 Gy/sec.로 0.5, 1, 1.5, 2, 3, 5, 7 Gy로 조사후에는 증가현상을 보이고 있다. Acid phosphatase활성도는 상기의 어떠한 선량에서도 나타나지 않고 있다. 잠재적으로 이러한 효소들은 방사선 피폭의 지표물질로 사용될 수 있으며 생화학적 지식과 기술을 이용한 좀더 나은 지표물질을 찾기 위하여 계속적인 조사가 필요하다.

• Nutrition Research and Practice
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• 제11권3호
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• pp.190-197
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• 2017

BACKGROUND/OBJECTIVES: Gallus gallus domesticus (GD) is a natural mutant breed of chicken in Korea with an atypical characterization of melanin in its tissue. This study investigated the effects of melanin extracts of GD on osteoblast differentiation and inhibition of osteoclast formation. MATERIALS/METHODS: The effects of the melanin extract of GD on human osteoblast MG-63 cell differentiation were examined by evaluating cell viability, osteoblast differentiation, and expression of osteoblast-specific transcription factors such as bone morphogenetic protein 2 (BMP-2), small mothers against decapentaplegic homologs 5 (SMAD5), runt-related transcription factor 2 (RUNX2), osteocalcin and type 1 collagen (COL-1) by reverse transcription-polymerase chain reaction and western blotting analysis. We investigated the inhibitory effect of melanin on the osteoclasts formation through tartrate-resistant acid phosphatase (TRAP) activity and TRAP stains in Raw 264.7 cell. RESULTS: The melanin extract of GD was not cytotoxic to MG-63 cells at concentrations of $50-250{\mu}g/mL$. Alkaline phosphatase (ALP) activity and bone mineralization of melanin extract-treated cells increased in a dose-dependent manner from 50 to $250{\mu}g/mL$ and were 149% and 129% at $250{\mu}g/mL$ concentration, respectively (P < 0.05). The levels of BMP-2, osteocalcin, and COL-1 gene expression were significantly upregulated by 1.72-, 4.44-, and 2.12-fold in melanin-treated cells than in the control cells (P < 0.05). The levels of RUNX2 and SMAD5 proteins were higher in melanin-treated cells than in control vehicle-treated cells. The melanin extract attenuated the formation of receptor activator of nuclear factor kappa-B ligand-induced TRAP-positive multinucleated RAW 264.7 cells by 22%, and was 77% cytotoxic to RAW 264.7 macrophages at a concentration of $500{\mu}g/mL$. CONCLUSIONS: This study provides evidence that the melanin extract promoted osteoblast differentiation by activating BMP/SMADs/RUNX2 signaling and regulating transcription of osteogenic genes such as ALP, type I collagen, and osteocalcin. These results suggest that the effective osteoblastic differentiation induced by melanin extract from GD makes it potentially useful in maintaining bone health.

• 한국의학물리학회지:의학물리
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• 제15권4호
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• pp.220-227
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• 2004

N형 칼슘통로의 비활성화기전에 관하여는 아직까지도 막전압의존성 기전과 칼슘의존성 기전간에 논란이 계속되고 있다. 2003년에 의학물리에 발표한 논문1)에서 본 연구자는 N형 칼슘통로의 비활성화 기전은 2가지 성분 -빠른 성분과 느린 성분을 가지고 있고 빠른 성분은 칼슘의존적이 아니며 오직 느린 성분만이 칼슘의존적일 가능성을 제시하였다. 본 논문에서는 막전압의존성 기전이 옳건 칼슘의존성 기전이 옳건 간에 세포 신호전달 체계로서 비활성화와 연계된 기전이 필요하므로 이러한 맥락에서 인산화 기전을 연구하였다. 흰쥐 경동맥 결절뉴론을 단일 세포로 얻은 후 whole cell patch clamp technique를 사용하여 N형 칼슘전류를 기록하고 대조 세포내액을 사용하였을 때와 phosphatase inhibitor인 okadaic acid를 포함한 세포내액을 사용하였을 때의 차이를 비교하였다. Okadaic acid에 의하여 비활성화정도가 증가되었고 이러한 okadaic acid 효과는 주로 N형 통로를 통하여 영향을 미침을 N형 칼슘통로 억제제인 $\omega$-conotoxin GVIA를 사용함으로써 확인하였다. Okadaic acid에 의한 비활성화 증가 효과는 protein kinase를 비특이적으로 억제하는 staurosporine에 의하여 억제되었고 또한 calmodulin dependent protein kinase의 특이적 억제제인 lavendustin C에 의하여 억제되었으므로 인산화과정이 N형 칼슘통로 비활성화와 관련되어 있고 특히 calmodulin을 통한 인산화과정이 주로 관여함을 확인하였다. 본 연구자가 발표한 선행논문1)에 의해 외부의 2가 양이온에 의해 빠른 비활성화가 진행되며, 본 논문에 의하여 인산화과정에 의해 빠른 비활성화가 촉진된다는 사실이 확인되었다. 그러나 본 연구결과만으로는 인산화과정이 비활성화 자체라고는 볼 수 없으며 단지 인산화과정에 의해 비활성화가 가속되었다고 해석할 수 밖에 없다. 인산화과정이 비활성화자 체인지 여부는 2가 양이온이 칼슘통로에 작용하는 결합부위에 관한 연구 및 인산화 부위가 칼슘통로인지 아니면 다른 조절 부위인지 여부를 확인할 수 있는 연구가 진행되어야 확실히 알 수 있을 것이다.

• Advances in Traditional Medicine
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• 제4권1호
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• pp.44-48
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• 2004

The Hexane Extract (HE) and Ethyl Acetate Soluble Fraction of the Methanolic Extract (EASFME) of the fruit pulp of Momordica dioica Roxb. (Cucurbitaceae) was evaluated for its anti-hepatotoxic activity in rats. Acute hepatotoxicity was induced by administering paracetamol (2 g/kg, p.o.) for 3 days. The extracts, at a dose of 400 mg/kg (p.o.) administered for 7 days exhibited a significant therapeutic effect by lowering Serum Glutamate Oxaloacetate Transaminase (SGOT), Serum Glutamate Pyruvate Transaminase (SGPT), Serum Alkaline Phosphatase (ALP) and Serum bilirubin and increasing the serum protein levels. These biochemical observations were supplemented by histopathological examination of the liver sections. The activity of extract was also comparable to the standard drug Silymarin, which is a well-known natural anti-hepatotoxic drug.

• Journal of Nutrition and Health
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• 제53권4호
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• pp.347-355
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• 2020

Purpose: Zinc is known to be associated with osteoblast proliferation and differentiation. Osterix as zinc-finger transcription factor is also related to osteoblast differentiation and bone formation. In the present study, we aimed to investigate whether zinc modulates osterix gene and protein expression in osteoblastic MC3T3-E1 cells. Methods: MC3T3-E1 cells were cultured in zinc-dependent concentrations (0, 0.5, 1, 5, or 15 µM Zn), along with osteogenic control (normal osteogenic medium) for 1 and 3 days. The gene and protein expression levels of osterix were analyzed by real-time reverse transcription polymerase chain reaction and Western blotting, respectively. Results: Zinc increased osteoblast proliferation in a concentration-dependent manner at day 1 and 3. Similarly, zinc increased the activity of osteoblast marker enzyme alkaline phosphatase in cells and media in a zinc concentration-dependent manner. Moreover, our results showed that the pattern of osterix gene expression by zinc was down-regulated within the low levels of zinc treatments (0.5-1 µM) at day 1, but it was up-regulated after extended culture period at day 3. Osterix protein expression by zinc showed the similar pattern of gene expression, which down-regulated by low zinc levels at day 1 and up-regulated back at day 3 as the early stage of osteoblast differentiation. Conclusion: Our results suggest that zinc modulates osterix gene and protein expression in osteoblasts, particularly in low level of zinc at early stage of osteoblast differentiation period.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제47권6호
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• pp.454-464
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• 2021

Objectives: This study aimed to investigate the in vitro osteoinductivity of the combination of bone morphogenetic protein-2 (BMP-2) and nanohydroxyapatite (nHAp) and the in vivo effects of implants coated with nHAp/BMP-2. Materials and Methods: To evaluate the in vitro efficacy of nHAp/BMP-2 on bone formation, bone marrow-derived mesenchymal stem cells (BM-MSCs) were seeded onto titanium disks coated with collagen (Col), Col/nHAp, or Col/nHAp/BMP-2. Protein levels were determined by a biochemical assay and reverse transcriptase-polymerase chain reaction. Stem cell differentiation was analyzed by flow cytometry. For in vivo studies with mice, Col, Col/nHAp, and Col/nHAp/BMP-2 were injected in subcutaneous pockets. Titanium implants or implants coated with Col/nHAp/BMP-2 were placed bilaterally on rabbit tibias and evaluated for 4 weeks. Results: In the in vitro study, BM-MSCs on Col/nHAp/BMP-2 showed reduced levels of CD73, CD90, and CD105 and increased levels of glycosaminoglycan, osteopontin, and alkaline phosphatase activity. After 4 weeks, the Col/nHAp/BMP-2 implant showed greater bone formation than the control (P=0.07), while no differences were observed in bone implant contact and removal torque. Conclusion: These results suggest that a combination of BMP-2 and an nHAp carrier would activate osseointegration on dental implant surfaces.

• BMB Reports
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• 제42권2호
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• pp.119-124
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• 2009

PI(3,4,5)$P_3$ produced by the activated PI3-kinase is a key lipid second messenger in cell signaling downstream of insulin. Skeletal muscle and kidney-enriched inositol phosphatase (SKIP) identified as a 5'-inositol phosphatase that hydrolyzes PI(3,4,5) $P_3$ to PI(3,4)$P_2$, negatively regulates the insulin-induced glycogen synthesis in skeletal muscle. However the mechanism by which this occurs remains unclear. To elucidate the function of SKIP in glycogen synthesis, we employed RNAi techniques to knockdown the SKIP gene in differentiating C2C12 myoblasts. Insulininduced phosphorylation of Akt (protein kinase B) and GSK-3$\beta$ (Glycogen synthase kinase), subsequent dephosphorylation of glycogen synthase and glycogen synthesis were increased by inhibiting the expression of SKIP, whereas the insulin-induced glycogen synthesis was decreased by overexpression of WT-SKIP. Our results suggest that SKIP plays a negative regulatory role in Akt/ GSK-3$\beta$/GS (glycogen synthase) pathway leading to glycogen synthesis in myocytes.

• Journal of Periodontal and Implant Science
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• 제27권4호
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• pp.923-939
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• 1997

This study was performed to evaluate the effect of mixed culture of rat's calvaria cells and periodontal ligament cells on calcification. These cells have been known to do important role on the periodontal tissue regeneration, especially alveolar bone and cementum. Experimental groups were made which based on the different rate of rat's calvaria cells and periodontal ligament cells, and then these cells were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum, $50{\mu}g/ml$ ascorbic acid, and 10mM/ ml $Na-{\beta}-glycerophosphate$. Each group was characterized by examining the cell proliferation rate, amount of total protein synthesis, alkaline phosphatase activity, and the number of calcified nodules in vitro. In cell proliferation rate , the cells of control groups were cultured Dulbecco's Modified Eagle's Medium contained with 10 % fetal bovine serum. The results were as follows : 1. The cell proliferation rate in control groups decreased stastically significantly along with the decrease of the rate of bone cells at 7 day and 20 day(P < 0.01). 2. The cell proliferation rate in experimental groups decreased stastically significantly along with decrease of the rate of bone cells at 3 day and 14 day(P < 0.01). 3. The amount of total protein synthesis was significantly decreased along with decrease of the rate of bone cells at 3 day and 6 day(p < 0.01). 4. Alkaline phosphatase activity showed reverse time dependent pattern and was significantly decreased along with decrease of the rate of bone cells during the experimental periods (P < 0.01). 5. Calcified nodules were observed in group 1 (Rat calvaria cells alone) for the first time, and the number of calcified nodule decreased stastically significantly along with the decrease of the rate of bone cells at 12 day(P < 0.01). From the above results, When bone cells and periodontal ligament cells were mixed cultured, the cell proliferation rate was mostly dependent on the actual rate of bone cells and same pattern was showed in amount of total protein synthesis, alkalinephosphatase activity, and the number of calcified nodules. And the calcified nodule forming capacity of bone cells was inhibited by periodontal ligament cells

• Applied Biological Chemistry
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• 제51권3호
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• pp.171-176
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• 2008

기질 화합물로써 3${\beta}$-Hydroxy-12-oleanen-28-oic acid 유도체(1-30)들과 그들의 protein tyrosine phosphatase(PTP)-1B 저해활성에 관한 비교분자 유사성 지수분석(CoMSIA)보델을 유도하였다. QSAR 모델의 통계 값은 CoMFA>CoMSIA${\geq}$HQSAR>2D-QSAR 모델의 순서로 양호하였다. 최적화된 CoMSIA F1 모델은 grid 3.0${\AA}$과 field fit 정렬조건에서 가장 족은 예측성과 상관성($r^2_{cf}$=0.754 및 $r^2_{ncv}$=0.976)을 나타내었다. 저해 활성에 관한 CoMSIA상의 기여비율(%)은 수소결합 받게장(48.9%), 입체장(25.8%) 및 소수성장(25.4%)의 순서이었다. 그러므로 기질 화합물의 PTP-1B에 대한 저해활성은 $R_4$-치환기의 수소결합 받게 장(A)에 의존적이었다. 등고도 분석 결과로부터 $R_1$-치환기는 수소결합 받게장이 작고 $R_3$-치환기는 입체장이 작으며 그리고 $R_4$-치환기는 수소결합 받게장, 소수성 및 입체장이 큰 치환기가 저해활성을 증가시킬 것으로 예측되었다.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.592-597
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• 2001

The pyruvate dehydrogenase complex (PDC) catalyzes the oxidative decarboxylation of pyruvate with the formation of $CO_2$, acetyl-CoA, NADH, and H+. This complex contains multiple copies of three catalytic components including pyruvate dehydrogenase(E1), dihydrolipoamide acetyltransferase(E2), and dihydrolipoamide dehydrogenase (E3). Two regulatory components (E1-kinase and phospho-E1 phosphatase) and functionally less-understood protein (protein X, E3BP) are also involved in the formation of the complex. In this study, cloning and characterization of a gene for human E3BP have been carried out. A cDNA encoding the human E3BP was isolated by database search and cDNA library screening. The primary structure of E3BP has some similar characteristics with that of E2 in the lipoyl domain and the carboxyl-terminal domain, based on the nucleotide sequence and the deduced amino acid sequence. However, the conserved amino acid moiety including the histidine residue for acetyltransferase activity in E2 is not conserved in the case of human E3BP. The human E3BP was expressed and purified in E. coli. The molecular weight of the protein, excluding the mitochondrial target sequence, was about 50 kDa as determined by SDS-PAGE. Cloning of human E3BP and expression of the recombinant E3BP will facilitate the understanding of the role(s) of E3BP in mammalian PDC.