Prostaglandin A₂-induced Apoptosis is Not Inhibited by Heme Oygenase-1 in U2OS Cells

Kyoung-Won Ko(고경원),Sun-Young Lee(이선영),Ji-Hyun Ahn(안지현),Jaetaek Kim(김재택),In-Kyung Kim(김인경),Ho-Shik Kim(김호식) 한국생명과학회 2008 생명과학회지 Vol.18 No.11

Prostaglandin A₂ (PGA₂)는 사람 골육종 세포인 U2OS 세포주에서 apoptosis와 heme oxygenase (HO)-1의 발현을 함께 유도하였다. PGA₂에 의한 apoptosis는 HO-1의 과도한 발현이나 HO-1에 대한 small interfering RNA에 의한 발현저하에 의하여 변동되지 않았으나 H₂O₂에 의한 세포사망은 HO-1의 발현 수준에 반비례하여 변동되었다. 또한 thiol antioxidant인 N-acetyl-L-cysteine (NAC)은 PGA₂에 의한 세포사망과 HO-1의 발현 증가를 모두 차단하였지만, non-thiol antioxidant인 butylated hydroxyanisole (BHA)과 ascorbic acid는 세포사망과 HO-1의 발현 유도를 차단하지 않았다. 이와 같은 결과들은 PGA₂는 산화성 손상에 의해서가 아니라 PGA₂의 thiol-reactivity에 의하여 apoptosis와 HO-1의 발현을 유도하며, HO-1의 발현은 PGA₂에 의한 apoptosis와는 독립적인 현상이거나 기능적으로 apoptosis 유도의 하부에 위치하고 apoptosis의 진행에는 기여하지 않을 것이라는 것을 시사해 준다. Prostaglandin A₂ (PGA₂), one of cyclopentenone PGs, induced both apoptosis and heme oxygenase (HO)-1 expression in U2OS cells. PGA₂-induced apoptosis was not perturbed by either over-expression or knock-down of HO-1, whereas H₂O₂-induced cell death was inversely modulated by the expression level of HO-1. In addition, N-acetyl-L-cysteine (NAC), a thiol antioxidant, blocked both apoptosis and HO-1 expression induced by PGA₂. But, non-thiol antioxidants like butylated hydorxyanisole (BHA) and ascorbic acid did not block either apoptosis or HO-1-induction. Taken together, these results suggest that PGA₂ induces both apoptosis and HO-1 expression, which are critically related to the thiol-reactivity of PGA₂, but not oxidative stress, and HO-1 expression may be independent or functionally located downstream of apoptosis by PGA₂ without contribution to apoptosis progression.

PWM 전력 컨버터를 이용한 배전용 무효전력 보상기 제어

고지호,김용현,김재홍,김일환 濟州大學校 産業技術硏究所 2000 산업기술연구소논문집 Vol.11 No.1

This paper presents the control method of reactive power in distribution system using PWM power converter. The PWM power converter controlled by space vector PWM method is voltage source type using IGBT switching device. Using the Park's transformation, three phase load current can be written in terms of component α and β current in a synchronously rotating reference frame. Two axis. the direct axis. α. and the quadrature axis. β, mean the active and reactive component in load current. Also. two components appear as de quantities in that frame. So it is easy to control the reactive power by controlling the d axis currents. And in accordance with the change of reactive power in load side. PWM power converter compensate the reactive power by generating the reactive current to the load side using PI control. To verify the theoretical analysis. results of computer simulation and experiment are presented to support the discussion

Isolation of Megastigmane Sesquiterpenes from the Silkworm (Bombyx mori L.) Droppings and Their Promotion Activity on HO-1 and SIRT1

Ji-Hae Park,Do-Gyeong Lee,Seung-Woo Yeon,Hyuk-Sang Kwon,Jong-Hee Ko,Dong-Jin Shin,Han-Sol Park,Yong-Soon Kim,Myun-Ho Bang,NAM-IN BAEK 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.4

The silkworm (Bombyx mori L.) droppings were extracted with 80% aqueous MeOH, and the concentrated extract was partitioned in succession with EtOAc, n-BuOH, and H_2O. From the EtOAc fraction, five megastigmane sesquiterpenes were isolated through repeated silica gel and ODS column chromatography. According to the results of spectroscopic data, such as NMR, MS, and IR, the chemical structures of the isolated compounds were determined as (3S,5R,8R)-3,5-dihydroxymegastigma-6,7-dien-9-one (1), (S)-dehydrovomifoliol (2), (6R,7E,9R)-9-hydroxy-4,7-megastigmadien-3-one (3), (3S,5R,6S,7E)-3,5,6-trihydroxy-7-megastigmen-9-one (4), (6R,9R)-9-hydroxy-4-megastigmen-3-one (5). Compounds 2 through 5 were isolated for the first time from silkworm droppings. GC/MS analysis indicated silkworm powder contained compound 3, and mulberry leaves contained compound 4. Compounds 1 and 5 increased the expression of heme oxygenase-1 and SIRT1 in HepG2 and HEK239 cells, respectively. Heme oxygenase-1 is considered to be an antioxidant enzyme that catabolizes heme to carbon monoxide, free iron and biliverdin, while SIRT1 is the mammalian homologue of the yeast silent information regulator (Sir)-2, which are involved in the suppression of inflammatory mediators or factors that may be used to improve atopy-related symptoms.

PWM 전력 컨버터를 이용한 배전용 무효전력 보상기 제어

고지호,김용현,김재홍,김일환 제주대학교 산업기술연구소 2000 尖端技術硏究所論文集 Vol.11 No.1

This paper presents the control method of reactive power in distribution system using PWM power converter. The PWM power converter controlled by space vector PWM method is voltage source type using IGBT switching device. Using the Park's transformation, three phase load current can be written in terms of component α and β current in a synchronously rotating reference frame. Two axis, the direct axis, α, and the quadrature axis, β, mean the active and reactive component in load current. Also, two components appear as dc quantities in that frame. So it is easy to control the reactive power by controlling the d axis currents. And in accordance with the change of reactive power in load side, PWM power converter compensate the reactive power by generating the reactive current to the load side using PI control. To verify the theoretical analysis, results of computer simulation and experiment are presented to support the discussion

F.D.M.을 應用한 1次元 壓密解析의 最適法 糾明

김지호,류권일,고영헌,김팔규 忠南大學校 産業技術硏究所 2001 산업기술연구논문집 Vol.16 No.2

In general, the term soft ground includes clayey soils, which have large compressibility and small shear resistance due to the external load. All process of consolidation in compressible soils can be explained in terms of transfer of load from an incompressible pore-water to a compressible soil structure. Therefore, one of the most important subjects about the characteristics of the time-dependant consolidation of the clay foundation by the charge of load may be the presumption of the final settlement caused by consolidation and the degree of consolidation according to the time. Pioneering work by Terzaghi imparted scientific and mathematical bases to many aspects of this subject and many people have used this theory to measure the consolidation settlement until now. In the paper, Finite Difference Methods for consolidation are considered. First, it is shown the stability criterion of Explicit scheme and the Crank-Nicolson scheme, although unconditionally stable in the mathematical sense, produces physically unrealistic solutions when the time step is large, it is also shown that The fully Implicit scheme shows more satisfactory behavior, but is less accurate for small time steps. And then we need to decide what scheme is more proper to consolidation. The purpose of this paper is to suggest the pertinent scheme to consolidation.

도심 교차로 노면 지표유출수의 초기수질특성에 관한 연구

최상용,고광백,이지영,임세호 한국환경과학회 2006 한국환경과학회지 Vol.15 No.4

자동화학 분석기 ISP-1000의 평가 Ⅱ

김문연,고은하,하경임,김지용,전창호 동국대학교 경주대학 1996 東國論集 Vol.15 No.-

검사방법의 평가로서 자동화기기에 대한 적절한 평가는 특히 수입에 전적으로 의존하는 국내여건을 생각할때 중요한 과제이다. ISP-1000은 대용량, 다항목의 선택적 생화학 자동 분석기로 국내에서는 거의 채택된 경험이 없는 기기로서 효율적인 선정을 하기위하여 4가지 화학검사에 대한 평가를 하였다. 시판되는 대조물질 Level Ⅰ,Ⅱ로 검사내 정밀도, 검사일간 정밀도, 직선성을 구하였으며 100명의 환자검체로는 Cobas Mira와의 상관성을 구하였다. 검사내 정밀도는 Level Ⅰ대조물질에서는 변이계수가 4.31-8.73%, Level Ⅱ 대조물질에서의 변이계수는 1.32-8.22%이었으며, 검사일간 정밀도는 Level Ⅰ 대조물질로 얻은 변이계수는 6.29-8.974%, Level Ⅱ 대조물질로 검사한 경우는 5.78-8.22%이었다. 직선성의 평가에서는 0.9917-0.9998의 우수한 직선성을 보여주었고(P<0.01), Cobas Mira에 대한 상관관계는 0.8427-0.9857의 범위에 있었다(P<0.01). 결론적으로 ISP-1000에 대한 4가지 화학검사의 평가에 있어서 검사중 정밀도, 검사일간 정밀도, 직선성은 우수하였으며, 상관관계는 만족할만하였으나 더 좋은 결과를 얻기위하여 parameter등에 대한 재검토가 필요한 것으로 생각되었다. It is an important task to evaluate autochemical analyzers as one of the labortory method evaluations, especially considering of the domestic environments almost depending on the import. By analyzing 4 chemical tests, we evaluated the high throughoutput, multichannel, selective and rarely adopted chemical autoanalyzer ISP-1000. We analyzed within run precision, between day precision, lineality with the commercial control materials, and correlation with 100 patients samples. In within run precision, CVs were ranged from 4.31~8.73% in Level I control material, l.32-8.22% in Level Ⅱ control material. In between day precision, CVs were ranged from 6.29-8.974% in Level I control material, 5.78-8.22% in Level Ⅱ control material. The lineality was excellent(r²>O,9917, p<O.Ol). The correlation coefficients between ISP-l000 and Cobas Mira were ranged from 0.8247∼0.9857%(P<O.0l). In conclusion, 4 chemical tests of ISP-l000 were acceptable in within run precision, between day precision and lineality, and correlation with Cobas Mira was good but adjusting the parameters would be necessary for the better results.

Synergistic Renoprotective Effect of Melatonin and Zileuton by Inhibition of Ferroptosis via the AKT/mTOR/NRF2 Signaling in Kidney Injury and Fibrosis

Jung Kyung Hee,Kim Sang Eun,Go Han Gyeol,Lee Yun Ji,Park Min Seok,Ko Soyeon,Han Beom Seok,Yoon Young-Chan,Cho Ye Jin,Lee Pureunchowon,Lee Sang-Ho,Kim Kipyo,Hong Soon-Sun 한국응용약물학회 2023 Biomolecules & Therapeutics(구 응용약물학회지) Vol.31 No.6

According to recent evidence, ferroptosis is a major cell death mechanism in the pathogenesis of kidney injury and fibrosis. Despite the renoprotective effects of classical ferroptosis inhibitors, therapeutic approaches targeting kidney ferroptosis remain limited. In this study, we assessed the renoprotective effects of melatonin and zileuton as a novel therapeutic strategy against ferroptosis-mediated kidney injury and fibrosis. First, we identified RSL3-induced ferroptosis in renal tubular epithelial HK-2 and HKC-8 cells. Lipid peroxidation and cell death induced by RSL3 were synergistically mitigated by the combination of melatonin and zileuton. Combination treatment significantly downregulated the expression of ferroptosis-associated proteins, 4-HNE and HO-1, and upregulated the expression of GPX4. The expression levels of p-AKT and p-mTOR also increased, in addition to that of NRF2 in renal tubular epithelial cells. When melatonin (20 mg/kg) and zileuton (20 mg/kg) were administered to a unilateral ureteral obstruction (UUO) mouse model, the combination significantly reduced tubular injury and fibrosis by decreasing the expression of profibrotic markers, such as α-SMA and fibronectin. More importantly, the combination ameliorated the increase in 4-HNE levels and decreased GPX4 expression in UUO mice. Overall, the combination of melatonin and zileuton was found to effectively ameliorate ferroptosis-related kidney injury by upregulating the AKT/mTOR/ NRF2 signaling pathway, suggesting a promising therapeutic strategy for protection against ferroptosis-mediated kidney injury and fibrosis.

Prevalence of BRCA1 and BRCA2 Mutations in Korean Breast Cancer Patients

Ko Byung Kyun,Cho Dae Yeon,Yoon Ho Sung,Hwang Ui Kang,Kwak Beom Seok,Ku Bo Kyung,Kang Hee Jun,Kim Ji Su,Ko Chang Dae,Yoon Kyung Sik,김준석,Son Byung Ho,Ahn Sei Hyun 대한의학회 2004 Journal of Korean medical science Vol.19 No.2

GCM emulator based on deep learning: an ENSO example

Ji-Ho Ko,Na-Yeon Shin,Jong-Seong Kug 한국기상학회 2023 한국기상학회 학술대회 논문집 Vol.2023 No.10