N-acetyl cysteine inhibits H2O2-mediated reduction in the mineralization of MC3T3-E1 cells by down-regulating Nrf2/HO-1 pathway

( Daewoo Lee ),( Sung Ho Kook ),( Hyeok Ji ),( Seung Ah Lee ),( Ki Choon Choi ),( Kyung Yeol Lee ),( Jeong Chae Lee ) 생화학분자생물학회(구 한국생화학분자생물학회) 2015 BMB Reports Vol.48 No.11

There are controversial findings regarding the roles of nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway on bone metabolism under oxidative stress. We investigated how Nrf2/HO-1 pathway affects osteoblast differentiation of MC3T3-E1 cells in response to hydrogen peroxide (H2O2), N-acetyl cysteine (NAC), or both. Exposing the cells to H2O2 decreased the alkaline phosphatase activity, calcium accumulation, and expression of osteoblast markers, such as osteocalcin and runt-related transcription factor-2. In contrast, H2O2 treatment increased the expression of Nrf2 and HO-1 in the cells. Treatment with hemin, a chemical HO-1 inducer, mimicked the inhibitory effect of H2O2 on osteoblast differentiation by increasing the HO-1 expression and decreasing the osteogenic marker genes. Pretreatment with NAC restored all changes induced by H2O2 to near normal levels in the cells. Collectively, our findings suggest that H2O2-mediated activation of Nrf2/HO-1 pathway negatively regulates the osteoblast differentiation, which is inhibited by NAC. [BMB Reports 2015; 48(11): 636-641]

Ethanol Extract of Ganoderma lucidum Augments Cellular Anti-oxidant Defense through Activation of Nrf2/HO-1

Lee, Yoo-hwan,Kim, Jung-hee,Song, Choon-ho,Jang, Kyung-jeon,kim, Cheol-hong,Kang, Ji-Sook,Choi, Yung-hyun,Yoon, Hyun-Min KOREAN PHARMACOPUNCTURE INSTITUTE 2016 Journal of pharmacopuncture Vol.19 No.1

Objectives: The mushroom Ganoderma lucidum has been widely used as a traditional herbal medicine for many years. Although several studies have focused on the anti-oxidative activity of this mushroom, the molecular mechanisms underlying its activity have not yet been clearly established. The present study investigated the cytoprotective effect of ethanol extract of Ganoderma lucidum (EGL) against oxidative stress (hydrogen peroxide, $H_2O_2$) and elucidated the underlying mechanisms in a C2C12 myoblast cell line. Methods: Oxidative stress markers were determined by using the comet assay to measure reactive oxygen species (ROS) generation and deoxyribonucleic acid (DNA) damage. Cell viability and Western blotting analyses were employed to evaluate the cellular response to EGL and $H_2O_2$ in C2C12 cells. Transfection with nuclear factor erythroid 2-related factor 2 (Nrf2)-specific small interfering ribonucleic acid (siRNA) was conducted to understand the relationship between Nrf2 expression and $H_2O_2$-induced growth inhibition. Results: The results showed that EGL effectively inhibited $H_2O_2$-induced growth and the generation of ROS. EGL markedly suppressed $H_2O_2$-induced comet-like DNA formation and phosphorylation of histone H2AX at serine 139 ($p-{\gamma}H2AX$), a widely used marker of DNA damage, suggesting that EGL prevented $H_2O_2$-induced DNA damage. Furthermore, the EGL treatment effectively induced the expression of Nrf2, as well as heme oxygenase-1 (HO-1), with parallel phosphorylation and nuclear translocation of Nrf2 in the C2C12 myoblasts. However, zinc protoporphyrin IX, a HO-1 inhibitor, significantly abolished the protective effects of EGL against $H_2O_2$-induced accumulation of ROS and reduced cell growth. Notably, transient transfection with Nrf2-specific siRNA attenuated the cytoprotective effects and HO-1 induction by EGL, indicating that EGL induced the expression of HO-1 in an Nrf2-dependent manner. Conclusion: Collectively, these results demonstrate that EGL augments the cellular anti-oxidant defense capacity through activation of Nrf2/HO-1, thereby protecting C2C12 myoblasts from $H_2O_2$-induced oxidative cytotoxicity.

소기업 기업가의 기업가적 자기효능감과 지각된 심각성이 실패에 대한 두려움을 매개로 기업가적 성과에 미치는 영향

유봉호(Yoo, Bong-Ho),김춘광(Kim, Choon-Kwang) 한국경영교육학회 2021 경영교육연구 Vol.36 No.6

[연구목적] 본 연구는 소기업 기업가의 기업가적 자기효능감과 지각된 심각성이 실패에 대한 두려움과 기업가적 성과에 어떤 영향을 미치는 살펴 본 탐색적 · 실증적 성격의 연구이다. [연구방법] 기업가적 자기효능감, 지각된 심각성을 독립변수로 상정하고, 실패에 대한 두려움을 매개로 기업가적 성과에 어떤 영향을 미치는지 확인하였다. 이를 위해, 서울 · 경기 지역 소재 소기업 기업가 총 167명 응답을 취합하여 분석하였다. [연구결과] 기업가적 자기효능감은 기업가적 성과에 직접 영향을 미쳤지만 실패에 대한 두려움에는 유의한 영향을 미치지 않았다. 반대로 지각된 심각성은 기업가적 성과에 직접 영향을 미치지 않으면서 실패에 대한 두려움에 유의한 영향을 미치는 것으로 나타났다. 또한 실패에 대한 두려움은 기업기적 성과에 유의한 영향을 미쳤다. 이로써 실패에 대한 두려움은 지각된 심각성과 기업가적 성과 사이에서 완전매개효과를 갖는 것이 확인되었다. [연구의 시사점] 이는 소기업 기업가의 기업가적 자기효능감과 지각된 심각성이 기업경영에 미치는 영향을 확인했다는 점, 실패에 대한 두려움을 매개로 기업가적 성과에 미치는 영향을 확인했다는 점, 기업 경영의 부정적 요소에 대한 메커니즘을 확인했다는 점 등에서 학술적 · 실무적 의의가 있다고 할 수 있다. [Purpose] This study is an exploratory and empirical study designed to examine how entrepreneurial self-efficacy and perceived severity of entrepreneurs in small enterprises affect the fear of failure and entrepreneurial performance in small businesses. [Methodology] By postulating entrepreneurial self-efficacy and perceived severity as independent variables, this study intended to identify how they affect entrepreneurial performance by the medium of fear of failure. To this end, a total of 167 responses from the survey conducted with entrepreneurs in small enterprises in Seoul and Gyeonggi regions were utilized for the final analysis. [Findings] It was found that entrepreneurial self-efficacy directly influenced entrepreneurial performance but did not significantly affect fear of failure. On the contrary, perceived severity had a significant effect on fear of failure but did not directly affect entrepreneurial performance. What’s more, the fear of failure had a significant effect on entrepreneurial performance. Therefore, it has been confirmed that fear of failure acts as a complete intermediary between perceived severity and entrepreneurial performance. [Implications] This study is of academic and practical significance in that it identifies the impact of entrepreneurial self-efficacy and perceived severity of entrepreneurs in small enterprises on corporate management, the impact on entrepreneurial performance through fear of failure, and the mechanism of negative elements of corporate management.

林土의 有機物의 分解速度와 無機養料의 垂直分布에 關한 考察

金遵敏,張楠基,鄭玩鎬 서울대학교 교육대학원 학술연구회 1966 論文集 - 서울대학교 교육대학원 Vol.3 No.-

Kim Choon Min, Chang Nam Kee and Chung Whan Ho: Decomposition rate of plant residue and the vertical distibution of mineral nutrients in the woodland soil. The relationship between decomposition rate of litter and the amount of mineral nutrients dispersed to the soil horizons were studied on the oak and pine forest stand. The results are as follows: 1. Decomposition rate of litter was highest in the F horizon of the oak stand, however in the pine stand it was highest in H horizon. 2. The correlation coefficients between decomposition rate and humus, organic carbon, moisture content, calcium, phosphorus, and nitrogen in the pine stand are; 0.90, 0.98, 0.76, 0.98, and 0.88, in oak stand; 0.97, 0.93, 0.92, 0.97, 0.74 and 0.73. 3. Factors which affect the decomposition rate of litter are humus, organic carbon, moisture content, calcium, phosphorus and nitrogen. 4. Among the variables, PH, moisture content and phosphorus under the oak and pine forest showed significant differences in each horizon. 5. C/N ratio of pine stands is higher than that of oak stands studied. 6. The vertical distribution of mineral nutrients is highly related with the amount of humus accumulated on top soil.

MO Theoretical Studies on the Effect of Bond Angle Distortion in Pyrazine

Lee, Ik-Choon,Kim, Ho-Soon Korean Chemical Society 1984 Bulletin of the Korean Chemical Society Vol.5 No.2

An enhancement of through-bond interaction by bond angle distortion in pyrazine was examined using various MO methods. Results of MINDO/3 geometry optimization with an angle (${\alpha}$) at $C_2$ atom fixed to 120∼90$^{\circ}$ lead to distorted structures in which the distorted bond is brought closer toward lone pair orbital n of N atom. It was also found that the bond angle distortion increased the P character at the atom $C_2$, resulting in an increased vicinal overlap between n and the $C_2-C_3$ bond. The FMO patterns of ${\sigma}$ framework showed three-fold degeneracy, one of which was of different symmetry which mixes in the symmetry adapted pair, $n_+\;and\;n_-;\;both\;n_+\;and\;n_-$ orbitals thus can interact with both FMOs of the ${\sigma}$ framework. The LCBO-MO analysis with partial elimination of bonds, antibonds or both, however, revealed that the main interaction of $n_+$ was with the HO-${\sigma}$ and that of $n_-$ was with the LU-${\sigma}^{\ast}$ orbital of the ${\sigma}$ framework.

복어중독에 의한 가사 상태에서 소생한 1예

송승찬,신진호,강석우,박경남,최호순,박근태,문희식,기춘석,이성희,윤병철,노우균,조균석,이민호 大韓應急醫學會 1998 대한응급의학회지 Vol.9 No.3

Tetrodotoxin is a neurotoxin produced by about 90 species of puffer fish and causes paralysis of central nervous system and peripheral nerves by blocking the movement of all monovalent cation. Ingestion of tetrodotoxin produces clinical manifestations such as paresthesias(within 10-45 min), vomiting, lightheadedness, salivation, muscle twitching, dysphagia, difficulty in speaking, convulsion and death that expressed by cardiopulmonary arrest with loss of brain stem reflex sometimes. Tetrodotoxin prevents or delays ischemia induced neuronal death by way of following 3 mechanisms. Firstly, it reduces the energy demand of the brain tissues. Secondly, it delays or even prevents anoxic depolarization. Finally, it deminishes ischemia induced cell swelling and cerebral edema. We report a case of puffer fish poisoning which presented with cardiopulmonary arrest and loss of brain stem reflex, but completely recovered by aggressive cardiopulmonary resuscitation.

골수이식 후 골밀도 및 골대사의 변화 : 2년 추적관찰 2-Year Prospective Study

이원영,강무일,오은숙,오기원,한제호,손현식,윤건호,차봉연,이광우,손호영,강성구,신완식,민우성,김춘추 대한내분비학회 2000 Endocrinology and metabolism Vol.15 No.4·5

조혈모세포이식술이 골수기질세포의 기원 및 조골세포로의 증식 및 분화에 미치는 효과

강무일,조성원,오은숙,백기현,이원영,오기원,김혜수,한제호,윤건호,차봉연,이광우,손호영,강성구,김춘추 대한내분비학회 2000 Endocrinology and metabolism Vol.15 No.4·5

신생아의 병적황달에 대한 임상혈액학적 고찰

박춘호,김성의,나창수 朝鮮大學校 附設 醫學硏究所 1987 The Medical Journal of Chosun University Vol.12 No.1

A clinical and hematological observation was performed on 398 nowborn infants with hyperbilirubinemia who were admitted 10 the Department of Pediatrics, Chosun University Hospital from January, 1980 ro June, 1985. The following results were obtained 1) The incidence of hyperbilirubinemia was more frequent in male(63.8%) than in female(36.2%) 2) In the observation of the gestational period, its incidence was highest in full-term neonate(70%) and the next was pre-term neonate (25%) 3) In the observation of the delivery type, the incidence was highest in neonates with normal delivery(82.0%) and the next was c-section delivery (11.0%) 4) Idiopathic hyperbilirubinemia was the most common cause of pathological hyperbilirubinemia and the next wero breast-fed induced jaundice(10.4%), infection(9.3%), blood incompatibility(8.6%) in frequent of order. 5) The most common blood types of mother-baby in ABO blood incompatibility was 0-A (48.5%) and the next was O-B(42.5%) 6) The exchange transfusion were performed on 34 cases(8.5%). The mean serum bilirubin levels before exchange transfusion were 26.7±4.9㎎% in the cases of idiopathic hyperbilirubinemia(14 cases) and 25.9±6.5㎎% in the cases of blood incompatibility (17 cases). 7) The mean bilirubin levels before and after the exchange transfusion were 26.4㎎% and 11.9㎎% respectively and reducing rate of the bilirubin by exchange transfusion was 55%. Second exchange transfusion was performed in 2 cases(5.8%).

Li_2B_4O_7의 TSEE에 對한 反應過程

李春鎬 全北大學校 基礎科學硏究所 1981 基礎科學 Vol.4 No.1

Exact expressions for activation energies are derived from analysis of the first-order and second-order theoretical glow curves. The TSEE glow curve of heat-treated L_i2B_4O_7 crystal can be resolved by the ultra violet excitation in four singular glow peaks at 175, 292, 360, 471℃, respectively. The activation energy, the capture cross-section and frequency factor for eaeh trap were determined. It can also be deduced from this result that the first and fourth peaks are due to a second order process and the second and therd peaks due to a first order process.