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Mycophenolic Acid에 의해 유도된 Jurkat 세포주 세포자멸사에서 Heme Oxygenase-1의 발현이 미치는 영향
이호균(Ho Kyun Lee),최수진나(Soo Jin Na Choi) 대한외과학회 2010 Annals of Surgical Treatment and Research(ASRT) Vol.78 No.6
Purpose: This study demonstrates that pharmacologic induction of heme oygenase-1 (HO-1) along with catalytic activation significantly modulated apoptosis of Jurkat cells induced by mycophenolic acid (MPA). Methods: Cells were cultured with the presence or absence of MPA. Flow cytometric analysis was performed after propidium iodide staining. Western blotting of HO-1, Bcl, and Bax was also performed. Cells were stained 4’-6-Diamidino-2-phenylindole (DAPI) and measured by flow cytometry in the absence or presence of CoPPIX. Results: Treatment of MPA decreased cell viability in a dose- and time-dependent manner. MPA-induced cell death was confirmed as apoptosis characterized by sub G0/G1 phase arrest. Expression of HO-1 assumes a pattern of decline after rising at the initial phase. CoPPIX, HO-1 inducer, significantly inhibited the cisplatin-induced apoptosis. Treatment of MPA resulted in reactive oxygen species (ROS) generation in Jurkat cells. CoPPIX attenuated ROS production in MPA-treated cells. Conclusion: This result suggests that the protective mechanism of HO-1 on MPA-induced cytotoxicity is associated with direct inhibition of ROS generation and mitochondrial permeability transition.
FK506이 T 림프구 사멸에서 활성산소 생성에 미치는 영향
이호균(Ho Kyun Lee),정상영(Sang Young Chung),최수진나(Soo Jin Na Choi) 대한외과학회 2009 Annals of Surgical Treatment and Research(ASRT) Vol.77 No.5
Purpose: Tacrolimus (FK506) has been widely used as an immunosuppressant in organ transplanted recipients to suppress organ rejection phenomenon. We investigated the role of oxidative stress and heme oxygense-1 by FK506 on human Jurkat T cells. Methods: The cells viability was examined by DAPI stain, enzyme activity of caspase family proteins, and western blotting for Baks, PUMA, iNOS, HO-1. Cells were cultured in the absence or presence of CoPPIX or ZnPPIX and the fluorescence intensity was analyzed using a flow cytometry. Results: Treatment with FK506 increased the generation of reactive oxygen species (ROS), including hydrogen peroxide and superoxide anion, and NO in Jurkat cells in a dose-dependent manner. Immunohistochemistry and Western blot analysis data revealed the hemoxygenase-1 (HO-1) was induced by the addition of FK506 in Jurkat cells. Induction of CoPP, HO-1 inducer, resulted in decreased intracellular H₂O₂ and NO concentrations. Instead ZnPP, an HO-1 competitive inhibitor did it reversely. In addition, ZnPP regulates iNOS protein synthesis by inhibition of HO-1. Conclusion: Increase of HO-1 expression would induce to decrease the intracellular H₂O₂ and NO concentrations. Also, HO-1 would regulate iNOS protein synthesis. Consequently, we can expect the regulation of HO-1 expression with concomitants use of FK506 to suppress organ rejection phenomenon by enhancing apoptosis.
올레핀계 수지/파라핀 오일 컴파운드의 자기윤활 재료로의 응용
이호균(Ho Kyun Lee),김도영(Do Young Kim),남기명(Gi Myeong Nam),서관호(Kwan Ho Seo) 한국고분자학회 2016 폴리머 Vol.40 No.4
본 연구에서는 대표적인 폴리올리핀계 고분자인 저밀도 폴리에틸렌(LDPE)과 고밀도 폴리에틸렌(HDPE)을 파라핀 오일과 함께 컴파운드하여 자기윤활소재로 응용하고자 하였다. 또한 컴파운드에서 용출되는 오일의 양을 제어하고, 오일에 의한 물리적 성질의 감소를 해결하고자 가교제인 dicumyl peroxide(DCP)를 이용하여 가교반응을 일으켰다. 또한 최근 여러 가지 고무소재를 대체하고 있는 물성보강제인 polyolefin elastomer(POE)를 첨가하여 경도를 낮추고 가교효과를 높이고자 하였다. DCP와 POE 함량을 달리한 컴파운드를 제작하고, 용출되는 오일 변화량, 기계적 성질, 열적 특성을 관찰하여 그 효과를 확인하였다. 결론적으로 DCP의 함량이 증가할수록 결합력 증가와 입체 그물 망상구조 형성으로 인해 오일 용출량이 감소되었다. 또한 인장강도와 파단 연신율이 크게 증가하였다. 그리고 POE의 함량이 증가할수록 인장강도는 감소하였지만, 증가된 탄성력과 고무상의 첨가로 인해 오일용출량과 경도를 낮추고, 파단 연신율을 크게 향상시켰다. In this study, polyolefin resins and paraffin oil were compounded for self-lubricative material. In order to control the migration of oil, the compounds were crosslinked using dicumyl peroxide (DCP). The polyolefin elastomer (POE) was added to enhance crosslinking and decrease hardness. To obtain optimum amount of DCP and POE in the compounds, various concentrations of both were applied. The resultant compounds were tested for migration of oil, physical and thermal properties. In conclusion, the high DCP contents improve cohesion which leads to the formation of a threedimensional network in the compounds. Thus, an increase in DCP decreases migration of oil and increases the tensile strength and elongation. On the other hand, an increase in POE decreases the hardness, migration of oil and tensile strength while it increases elongation.
이호균(Ho Kyun Lee),최수진나(Soo Jin Na Choi) 대한외과학회 2009 Annals of Surgical Treatment and Research(ASRT) Vol.77 No.6
Sigmoid volvulus is uncommon in children. Chronic constipation rarely leads to sigmoid volvulus. We report the experience of a case of sigmoid volvulus led by chronic constipation in a child. An 11-year-old girl complained abdominal pain and constipation, which had continued for previous 3 years. Under the impression of sigmoid volvulus by simple abdominal x-ray and abdominal computed tomography, emergency colonoscopic reduction of the volvulus tried to fail to the emergency segmental resection of the twisted sigmoid colon. After 3 months of operation, her constipation improved gradually with no other untoward symptoms so far.