• Korean Journal of Head & Neck Oncology
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• v.29 no.1
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• pp.1-10
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• 2013

연구배경 및 목적 표피성장인자수용체(EGFR)는 HER2/neu(erbB2), HER3(erbB3), HER4(erbB4)를 포함하는 receptor tyrosine ki-nase의 erbB 그룹에 속하는 수용체이다. 표피성장인자수용체의 과발현은 다양한 종류의 암, 특히 두경부편평세포암에서 예후를 악화시킨다고 알려져 있다. 이에 저자들은 하인두편평세포암에서 표피성장인자수용체의 발현 및 분포를 확인하고, 하인두암에서 표피성장인자(EGF)가 암세포의 증식과 침습에 미치는 영향에 대해 알아보고자 하였다. 대상 및 방법 57명의 하인두편평세포암 환자의 조직에서 표피성장인자수용체의 발현을 면역화학적염색을 통해 확인하고, 이에 대해 임상병리학적 요인과 생존율에 대한 분석을 시행하고, 일부 환자의 정상 및 암조직에서 Western blot을 시행하였다. 하인두편평세포암 세포주인 FaDu에서 proliferative assay, colony dispersion, wound healing assay, invasion assay를 시행하여, 하인두암의 진행에서 표피성장인자의 역할에 대하여 분석하였다. 또한 RT-PCR과 Zymography를 통하여 Matrix metalloproteinase(MMP)-2, 9의 발현을 확인하였다. 결 과 63.2%의 하인두편평세포암 조직에서 표피성장인자수용체의 발현이 확인되었다. 표피성장인자수용체의 발현은 정상조직에서 비하여 하인두암 조직에서 유의하게 증가되어 있었으며, 병리학적 병기(p=0.022)가 올라갈수록 유의하게 증가하였으나, 증례수의 제한으로 생존율에서는 통계적 유의성을 얻지는 못했다(p=0.053). in vitro의 결과로 표피성장인자를 FaDu 세포주에 처리하였을 때, FaDu 세포주의 증식이 유의하게 증가되었으며(p<0.05), Transwell invasion chamber상 침습의 증가가 확인되었다(p<0.05). RT-PCR과 zymogram 실험상 표피성장인자처리시 FaDu 세포주의 MMP-2, 9이 발현이 증가되고 활성화되는 것이 확인하였다. 결 론 본 연구에서 표피성장인자수용체의 과발현이 하인두암의 예후 인자로서의 가능성을 확인하였고, 표피성장인자가 하인두편평세포암의 증식과 침습에 관여하는 것을 확인하였다.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.7-11
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• 2004

eIF5B is a translation initiation factor that delivers Met-$tRNA^{Met}$ to AUG start codon and subsequently joins the small and large ribosomes. In order to study the function of eIF5B encoded by FUN12, we constructed FUN12 which lacked 5' end of its sequence. We found that this construct lacking almost all of its promoter in pRS plasmid partially complemented slow growth phenotype of fun12 deletion strain. Interestingly, this construct expressed N-terminally truncated eIF5B and its expression level was about 5% of that of wild type eIF5B. Low amount of the eIF5B expressed additionally in fun12 deletion strain played a direct role as a limiting factor for its growth. This limiting factor eIF5B in those strains also modulates activities of overall translation in vitro.

• KSBB Journal
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• v.7 no.2
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• pp.92-95
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• 1992

A model for the role of serum was proposed to develop a low serum medium for the large scale cu1ture of mammalian cell. The strategy of medium development adopted in this study facilitated the understanding of the role being carried out by the serum in the culture of hybridoma KAl12 cell line. In this model, the serum components were divided into two main groups : the first group encompasses the nutrient factors that determine the maximum cell density and the second group includes the growth factors that regulate the cell growth rate, The model prediction was compared with the experimental results. The model enabled us to find out several useful aspects of medium composition for cell growth. 1) One particular component in the basal medium became limiting factor when serum concentration level was more than 7%. 2) The growth regulating factors and nutrient factors limited the cell growth at 3% and 5% serum concentration levels respectively.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.158-164
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• 2013

The most frequently encountered problems at fixture-implantation sites are lack of adequate bone and proximity to anatomic structures. It is generally accepted that growth factors play an essential role in the healing process and tissue formation, and they have become the focus of grafting materials research. The granules in platelets contain high concentrations of various growth factors. In particular, platelet-rich fibrin (PRF) is a second-generation platelet concentrate that allows the production of fibrin membranes enriched with platelets and growth factors from an anticoagulant-free blood harvest. This study investigated the in vitro effects of PRF on osteoblasts, in terms of the key cellular functions, and especially the effects on two growth factors, the homodimer of platelet-derived growth factor subunit B (BPDGF-BB) and transforming growth factor (TGF)-${\beta}1$, which are associated with wound healing and regeneration (i.e., proliferation and differentiation). The following parameters were investigated: PDGF-BB and TGF-${\beta}1$ levels in PRF, cell viability, alkaline phosphatase (ALP) activity, type 1 collagen synthesis, and the expressions of osteoblast differentiation markers (ALP and runt-related transcription factor 2) and bone matrix proteins (type 1 collagen). The release of autologous growth factors from PRF was maintained for a reasonable period of time, and exerted positive effects on the proliferation and differentiation of osteoblasts. The use of PRF thus appears to be a promising method for enhancing bone healing and remodeling.

• Korean Journal of Ecology and Environment
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• v.35 no.1 s.97
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• pp.1-9
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• 2002

In order to understand the relationship between succession of phytoplankton community structure and inorganic nutrients and particulate organic matters, a one station in Kyungan stream in Korea during the dry season was chosen. Water samplings were carried out once a week from 18 August to 13 November 1993. The DIN concentration distributed always abundantly, however, phosphate and silicate gradually reduced during the period. Phytoplankton community had a peak chlorophyll a concentration of $90.6\;{\mu}g/l$ in late summer (21 August 1993) and a second peak of $29.7\;{\mu}g/l$ in autumn (2 October 1993). After then late autumn was characterined by relatively low chlorophyll a concentration of $15{\sim}16\;{\mu}g/l$. Seasonal fluctuation of chlorophyll a concentrations were correlated with measured POC and PON concentrations: phytoplankton blooming may be a major factor controlling POC and PON concentrations in this ecosystem. Phosphate plays an most important role as a limiting factor of phytoplankton growth. However, when Si/P ratio low, silicate may be a more critical limiting factor than phosphate. Shifts of P-limitation to Si- limitation the succession of dominant phytoplankton can in duce: diatom to cyanobacteria such as Anabaena, Microcystis and Oscillatoria.

• Korean Journal of Environmental Biology
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• v.29 no.2
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• pp.98-106
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• 2011

In order to investigate water quality factors controlling chlorophyll-$a$ concentrations, the by-daily monitoring was conducted from February to November 2010 in 4 stations of Masan Bay. Seasonal variability in physico-chemical factors was mainly controlled by freshwater loading as a result of precipitation: chemical oxygen demand, suspended solids and nutrient concentrations rapidly increase during the heavy rainy season, whereas they decrease in the dry season. From late winter to mid spring, phosphorus and silica sources relative to Redfield ratio were probably functioned as limiting factor for phytoplankton flourishing in surface waters, but nitrogen concentration during mid-spring to autumn might be responsible for the increase of phytoplankton biomass. The multiple regression analysis revealed that variations in chlorophyll-$a$ concentration may be strongly correlated with changes of water temperature, chemical oxygen demand, dissolved inorganic phosphorus in spring, and salinity, chemical oxygen demand and precipitation in summer. Consequently, in the Masan Bay, a heavy rainfall event is an important factor to determine changes of biotic and abiotic factors, and in addition the dynamics of chlorophyll-$a$ concentration are strongly affected by changes of hydrological factors, especially water temperature, precipitation and nutrients.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.306-312
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• 2017

Changes in the cell growth and lipid accumulation of marine microalga Dunaliella tertiolecta were investigated in response to the combination of different stress factors including the variation of iron supply as a primary stress factor and different options in light irradiation and $CO_2$ supply as a secondary stress factor. High or limited Fe conditions could act as a stress for lipid synthesis. As a secondary stress factor, non-$CO_2$ condition was good for lipid accumulation, but the overall cell growth was sacrificed significantly after a long-time cultivation. Dark condition as a secondary stress factor also favored lipid accumulation and the extent of cell density reduction at the early period in the dark was small compared to other stress conditions. The two-stage cultivation strategy was necessary to maximize lipid production because tendencies of the cell growth and lipid content were not identical under the chosen stress condition. The first stage was for preparing a high cell density under the normal growth-favoring condition and the second stage was the stress condition to induce lipid accumulation in a short time. The short-term (12 h) incubation under the 5X Fe (3.25 mg/L) and dark conditions resulted in the best lipid productivity of 1.44 g/L/d providing 2 g/L inoculum at the second stage.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.50-55
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• 1995

진동하는 경계면의 진동장 및 음장을 재구성하기 위하여 음장측정치 및 경계요소법을 이용한 음향 홀로그래피 방법을 연구하였다. 특히, 측정잡음 및 전달행렬의 특이성에 의해 발생하는 재구성 오차에 대하여 고찰하였다. 재구성의 정확도를 나타내기 위하여 전달행렬의 특이인자를 도입하였다. 예제로 한면이 진동하는 직육면체 상자를 고려하였다. 결과로부터 매우 작은 측정잡음에 대해서도 전달행렬의 특이성 재구성 오차가 크게 발생하며, 측정위치에 따라 전달행렬의 특이성이 크게 영향 받음을 확인하였다. EfI방법을 이용하여 최적의 측정점을 선택한 결과 전달행렬의 특이성을 크게 줄일 수 있었으며 이때 측정점의 위치는 가진주파수에 관계없이 큰 음장이 형성되는 소음원의 근접장에 위치함을 알 수 있다. 또한 저주파 가진에 비해 고주파 가진이 작은 특이인자값을 나타내며, 따라서 재구성 오차가 작음을 알 수 있었다. 재구성장의 정밀도를 향상시키기 위하여, 부가적으로 진동장의 norm을 제한하는 적절화방법을 도입하였다. 모델의 최소자승오차를 최소화 하는 최적의 적절화변수를 추정하여 이로부터 재구성 오차를 줄일 수 있었다.

• KSBB Journal
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• v.9 no.5
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• pp.475-482
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• 1994

To find out the optimum conditions for the cell growth and the synthesis of PHB in A. eutrophus, the effects of culture conditions and extracellular by-products were investigated. Glucose and$>(NH_4)_2HP0_4$were optimum carbon and nitrogen sources, respectively for cell growth of A. eutrophus. PHB accumulation was stimulated by deficiency of nutrients such as $>NH_4^{3-}, P0_4^{3-}, and Mg^{2+}$ in the medium. $>NH_4^+$, deficiency was the most suitable for PHB accumulation and PHB accumulation ratio was reached 42% of dry cell weight. The specific growth rate was increased 1.5 times by addition yeast extract in the medium, and proteins and vitamins are supposed a main factor of that effect. The extracellular products such as ethanol and butanediol were excreted under anaerobic conditions. And ethanol was found to decrease the specific growth rate.

• Journal of Nutrition and Health
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• v.53 no.4
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• pp.369-380
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• 2020

Purpose: It has been previously reported that breast tumor incidence, growth, and metastasis are stimulated by high-fat diet but reduced by caloric restriction. However, few studies have elucidated the effects of dietary change from a high-fat diet after breast cancer initiation. Therefore, in this study, we attempted to provide practical assistance to breast cancer prevention and management by investigating the effects of dietary change from a high-fat diet to normal diet on breast cancer growth and metastasis. Methods: The experimental animals were divided into 2 groups (high-fat diet control [HFC] group and diet restriction [DR] group) and consumed a high-fat diet for 8 weeks. 4T1 cells were transplanted into subcutaneous fat or tail vein to measure the growth and metastasis of breast cancer. The HFC and DR groups continuously ingested either high-fat diet or AIG-93G diet for 5 weeks or 3 weeks, respectively. Cell proliferation and apoptosis markers from tumor tissues were analyzed by Western blot analysis. The data were analyzed using the SPSS 25.0 package program. Results: The results show that the DR group significantly reduced breast tumor initiation, growth, and tumor tissue weight compared to the HFC group. The DR group suppressed tumor growth by decreasing proliferation and inducing apoptosis through down-regulation of Bcl-xL and up-regulation of caspase-3 activity. Furthermore, the DR group significantly reduced numbers of metastasized tumors in lung tissues. Conclusion: These results suggest that dietary change from a high-fat diet to normal diet decreased breast growth by reducing cell proliferation and inducing apoptosis and metastasis. Taken together, these results indicate that dietary change to a low-fat and balanced diet might suppress breast tumor growth and metastasis even after tumor diagnosis.