• 미생물학회지
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• 제52권2호
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• pp.236-241
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• 2016

탈유비퀴틴 효소 중 PPPDE 상과에 속하는 Schizosaccharomyces pombe의 $sdu1^+$ 유전자가 유비퀴틴 C-말단 가수분해 효소 활성을 갖는 단백질을 인코딩하고, 산화적 및 일산화질소 스트레스 방어에 관여함이 이전에 밝혀진 바 있다. 예비적인 본 연구는 정상적인 및 과잉발현의 조건에서 S. pombe 유비퀴틴 C-말단 가수분해 효소 활성의 활성산소종 의존성 조절에 초점을 맞추었다. 과산화수소, 수퍼옥사이드 라디칼 생성하는 메나디온 및 일산화질소 생성하는 sodium nitroprusside (SNP)에 노출시킨 S. pombe 세포에서 유비퀴틴 C-말단 가수분해 효소 활성이 감소되었다. 환원형 글루타치온과 그 전구체인 N-acetylcysteine은 과산화수소의 존재 유무에 상관없이 유비퀴틴 C-말단 가수분해 효소 활성을 현저하게 증강시켰다. 그러나, 과산화수소의 부재 시 혹은 존재 시 활성산소종에 미치는 글루타치온과 N-acetylcysteine의 영향은 같은 조건 하에서의 유비퀴틴 C-말단 가수분해 효소 활성 패턴과 상반되었다. 과잉발현의 유비퀴틴 C-말단 가수분해 효소 활성을 보이는 재조합 플라즈미드 pYSTP를 보유하는 S. pombe 세포에서 유비퀴틴 C-말단 가수분해 효소 활성도 과산화수소, 메나디온 및 SNP에의 노출되는 조건에서 감소되었지만, 벡터 대조 세포에서 보다는 높게 유지되었다. 요약하면, S. pombe 유비퀴틴 C-말단 가수분해 효소 활성은 활성산소종에 의하여 하향조절 되지만, 그 의의는 현재로썬 알려지고 있지 않은 상태이다.

• Tuberculosis and Respiratory Diseases
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• 제73권1호
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• pp.22-31
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• 2012

Background: Oxidation plays an important role in acute lung injury. This study was conducted in order to elucidate the effect of repetitive post-treatment of N-acetylcysteine (NAC) in lipopolysaccaride (LPS)-induced acute lung injury (ALI) of rats. Methods: Six-week-old male Sprague-Dawley rats were divided into 4 groups. LPS (Escherichia coli 5 mg/kg) was administered intravenously via the tail vein. NAC (20 mg/kg) was injected intraperitoneally 3, 6, and 12 hours after LPS injection. Broncho-alveolar lavage fluid (BALF) and lung tissues were obtained to evaluate the ALI at 24 hours after LPS injection. The concentration of tumor necrosis factor ${\alpha}$ (TNF-${\alpha}$) and interleukin $1{\beta}$ (IL-$1{\beta}$) were measured in BALF. Nuclear factor ${\kappa}B$ (NF-${\kappa}B$), lipid peroxidation (LPO), and myeloperoxidase (MPO) were measured using lung tissues. Micro-computed tomography (micro-CT) images were examined in each group at 72 hours apart from the main experiments in order to observe the delayed effects of NAC. Results: TNF-${\alpha}$ and IL-$1{\beta}$ concentration in BALF were not different between LPS and NAC treatment groups. The concentration of LPO in NAC treatment group was significantly lower than that of LPS group ($5.5{\pm}2.8$ nmol/mL vs. $16.5{\pm}1.6$ nmol/mL) (p=0.001). The activity of MPO in NAC treatment group was significantly lower than that of LPS group ($6.4{\pm}1.8$ unit/g vs. $11.2{\pm}6.3$ unit/g, tissue) (p<0.048). The concentration of NF-${\kappa}B$ in NAC treatment group was significantly lower than that of LPS group ($0.3{\pm}0.1\;ng/{\mu}L$ vs. $0.4{\pm}0.2\;ng/{\mu}L$) (p=0.0001). Micro-CT showed less extent of lung injury in NAC treatment than LPS group. Conclusion: After induction of ALI with lipopolysaccharide, the therapeutic administration of NAC partially attenuated the extent of ALI through the inhibition of NF-${\kappa}B$ activation.

• 대한임상독성학회지
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• 제16권2호
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• pp.68-74
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• 2018

Purpose: In 2012, a revised guideline for acute acetaminophen overdose was proposed in the UK, recommending that the treatment threshold should be lowered to 100 mcg/ml at 4 hours after ingestion without risk stratification of hepatotoxicity. However, the poison centers in some developing countries do not have laboratory resources to provide serum drug levels in time. The primary aim of the study is to evaluate the cut-off value of reported dose per kilogram to determine when N-acetylcysteine treatment is warranted under the revised guideline. Methods: Data were collected retrospectively from the toxicology registry of an urban emergency medical center between 1st January 2010 and 30th June 2017. Inclusion criteria were single acute overdose of more than 75 mg/kg in 15 hours from ingestion and over 14 years of age. Subgroups were created by 25 mg/kg increments of reported dose, then sensitivity, specificity, positive predictive value and negative predictive value were calculated for the cut-off values of 100 mg/kg, 125 mg/kg, 150 mg/kg and 175 mg/kg for toxic serum level over '100-treatment line'. Results: A total of 99 patients were enrolled in the study; 24 patients showed toxic serum levels (24.2%). Zero of 17 patients with an ingestion dose under 100 mg/kg showed toxic level (0%), and 0 of 15 under 125 mg/kg (0%), 2 of 14 under 150 mg/kg (14.3%), and 4 of 12 under 175 mg/kg (33.3%) had toxic levels. The higher the ingested dose per kilogram of weight, the higher the frequency of the toxic serum concentration on the first test (${\chi}^2$ test for trend, ${\chi}^2=22.66$, p-value<0.001) and the sensitivity of each value was 100%, 100%, 92% and 76%. Conclusion: In acute single acetaminophen intoxication, the ingestion dose of 100 mg/kg of weight will be useful in determining the need for the N-acetylcysteine antidote in the indigent laboratory environment.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.325.2-325.2
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• 2002

We investigated the effect of bovine lactoferricin (Lfcin-B) on cell cycle regulation and caspase activation in tumor cells. Treatment with Lfcin-B resulted in the production of intracellular reactive oxygen species (ROS) during apoptosis of THP-1 cells. Biochemical analysis revealed that Lfcin-B-induced apoptosis. the cell cycle arrest and caspase activation were completely abrogated by addition of an antioxidant such as N-acetylcysteine(NAC). (omitted)

• Journal of Photoscience
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• 제9권2호
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• pp.146-149
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• 2002

Oxidative stress evoked hy Ultraviolet (UV) exposure has been suggested to be involved in UV-induced skin carcinogenesis. In this study, the role of oxidative stress in UV-carcinogenesis was evaluated by applying N-Acetylcysteine (NAC) in animal model of hairless-mouse. NAC is known to be a precursor of glutathione, which was converted to glutathione in cytoplasm, acting as an intracellular free radical scavenger. The glutathione levels in hairless mouse skin after one time application of NAC increased significantly. With and without the pre-treatment of NAC, hairless-mice were exposed to UVB three times a week, at total dose 274.4 kJ in 80 times, and the timing of tumor-development, incidence of skin tumor and the histopathology of tumors were observed. 8-hydroxy-2'-deoxyguanosine (8-0HdG), a typical form of oxidative damage in DNA has been also investigated in the course of experiment. The decrease of 8-0HdG formation of UVB- exposed skin compared to controls was observed in the early stage of experiment in the NAC-treated mice. In addition, initial tumor development delayed significantly in NAC-treated group. Finally the number of the tumor developed in the NAC-treated mice was fewer though not significant. These results suggest that antioxidants may have inhibitory effect in the initial step of UVB-induced carcinogenesis of hairless mice.

• 동의생리병리학회지
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• 제18권3호
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• pp.900-907
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• 2004

The antiproliferative effect of the water extract of the branch and root bark of Ulmi Pumilae Cortex(WEUPC) was investigated on the p53-negative human leukemia cell line (HL-60). A dose- and time-dependent inhibition of cell growth was observed; this effect appears to be due to induction of apoptosis. Involvement of oxidative stress is indicated by a dose-dependent increase in intracellular reactive oxygen species levels. In addition. anti-apoptic effect was observed in the cells simultaneously treated with WEUPC and the anti-oxidant N-acetylcysteine. WEUPC did not affect the anti-apoptotic Bcl-2 and the pro-apoptotic Bax, whereas p21/sup WAF1/CIPl/ was enhanced in a dose- and time-dependent fashion; this effect was partially inhibited by N-acetylcysteine. The increase in p21/sup WAF1/CIPl/ was accompanied by a parallel accumulation of cells in the G1 phase of the cycle. These results suggest that the p53-independent induction of p21/sup WAF1/CIP/ and the induction of apoptosis may mediate the anti proliferative effect of WEUPC at least in this study; on the basis of this observation, WEUPC could be proposed as an useful adjunct to the treatment of p53-deficient tumors, which are often refractory to standard chemotherapy.

• Biomolecules & Therapeutics
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• 제13권4호
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• pp.256-262
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• 2005

We examined the signaling molecules involved in the 6-hydroxydopamine (6-OHDA)-induced neuronal cell death and increase in cellular glutathione (GSH) level in SK-N-SH cells. The 6-OH-DA-induced cell death was significantly prevented by the pretreatment with N-acetylcysteine (NAC), a thiol antioxidant, and BAPTA, an intracellular $Ca^{2+}$ chelator. Although 6-OHDA induced ERK phosphorylation, the pretreatment with PD98059, an ERK inhibitor, did not block 6-OHDA-induced cell death. In addition, the 6-OHDA-induced activation of caspase-3, a key signal for apoptosis, was blocked by the pretreatment with NAC and BAPTA. While the level of reactive oxygen species (ROS) was significantly increased in the 6-OHDA-treated cells, the cellular GSH level was not altered for the first 6-hr exposure to 6-OHDA, but after then, the level was significantly increased, which was also blocked by the pretreatment with NAC and BAPTA, but not by PD98059. Depletion of GSH by pretreating the cells with DL-buthionine-(S,R)-sulfoximine (BSO), a glutathione synthesis inhibitor, rather significantly potentiated the 6-OHDA-induced death. In contrast to the pretreatment with NAC, 6-OHDA-induced cell death was not prevented by the post-treatment with NAC 30 min after 6-OHDA treatment. The results indicate that the GSH level which is increased adaptively by the 6-OHDA-induced ROS and intracellular $Ca^{2+}$ is not enough to overcome the death signal mediated through ROS-$Ca^{2+}$ -caspase pathway.

• Toxicological Research
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• 제27권3호
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• pp.161-166
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• 2011

Carbon black, a particulate form of pure elemental carbon, is an industrial chemical with the high potential of occupational exposure. Although the relationship between exposure to particulate matters (PM) and cardiovascular diseases is well established, the cardiovascular risk of carbon black has not been characterized clearly. In this study, the cytotoxicity of carbon black to vascular smooth muscle and endothelial cells were examined to investigate the potential vascular toxicity of carbon black. Carbon black with distinct particle size, N330 (primary size, 28~36 nm) and N990 (250~350 nm) were treated to A-10, rat aortic smooth muscle cells and human umbilical vein endothelial cell line, ECV304, and cell viability was assessed by lactate dehydrogenase (LDH) leakage assay. Treatment of carbon black N990 resulted in the significant reduction of viability in A-10 cells at 100 ${\mu}g$/ml, the highest concentration tested, while N330 failed to cause cell death. Cytotoxicity to ECV304 cells was induced only by N330 at higher concentration, 200 ${\mu}g$/ml, suggesting that ECV304 cells were relatively resistant to carbon black. Treatment of 100 ${\mu}g$/ml N990 led to the elevation of reactive oxygen species (ROS) detected by dichlorodihydrofluorescein (DCF) in A-10 cells. Pretreatment of antioxidants, N-acetylcysteine (NAC) and sulforaphane restored decreased viability of N990-treated A-10 cells, and N-acetylcysteine, but not sulforaphane, attenuated N990-induced ROS generation in A-10 cells. Taken together, present study shows that carbon black is cytotoxic to vascular cells, and the generation of reactive oxygen contributes to the development of cytotoxicity. ROS scavenging antioxidant could be a potential strategy to attenuate the toxicity induced by carbon black exposure.

• 분석과학
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• 제12권1호
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• pp.28-33
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• 1999

생체 시료내의 glutathione(GSH)을 monobromobimane(MBB)이나 4-fluoro-7-sulfobenzofurazan(SBD-F)으로 최적 유도체화 조건을 확립하였고 고성능 액체 크로마토그래피(HPLC)/형광 검출기(FLD)를 사용하여 정량분석 하였다. MBB로 유도체화한 경우에는 검출한계가 $0.03{\mu}g/mL$으로서 SBD-F를 사용한 경우보다 감도가 약 200배 정도 향상되었다. 이때 내부표준물질로서 N-acetylcysteine을 사용하였으며, MBB 유도체의 분리능을 개선시키기 위해 tetrabutylammonium 이온을 counter 이온으로 선택하였다. 위의 조건의 이온쌍 크로마토그래피를 이용하여 분석한 결과 $0.08{\sim}8.33{\mu}g/mL$ 농도 범위에서 상관계수가 0.998 이상으로 좋은 직선성을 보여주고 있다. 재현성을 조사한 결과 세 가지 다른 농도에서 상대 표준 편차가 5% 이내로 나타났다. 이 방법은 혈장, 조직 등의 생체 시료중 GSH의 분석법으로 적합하다는 것을 확인하였다.

• Applied Biological Chemistry
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• 제44권1호
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• pp.1-6
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• 2001

본 연구에서는 Ttichoplusia ni 세포의 apoptosis 유도 및 억제 현상의 기초연구를 수행하였다. Apoptosis 유도제로 알려진 hygromycin B에 의한 세포 성장 저해는 $200\;{\mu}/ml$의 수준에서부터 나타났고, $400\;{\mu}/ml$ hygromycin B를 처리한 세포에서는 배양 후 2일부터 DNA가 분절되어지는 것을 확인할 수 있었다. 그러나 dexamethasone과 sodium butyrate를 첨가시 세포성장은 저해되었지만 DNA 분절현상이 보이지 않아 apoptosi의 유발여부를 확인할 수 없었다. 그리고 caspase 기능억제제의 apoptosis 지연효과를 보기 위해 $200\;{\mu}/ml$ hygromycin B로 apoptosis를 유발한 상태에서 Ac-DEVD-CHO를 첨가하여 세포성장을 비교해 본 결과 이 저해제에 의해 약 36%정도 apoptosis가 억제되었음을 확인하였다. N-acetylcysteine의 경우도 apoptosis지연 효과가 있었다. Bcl_계에 속하는 anti-apoptotic 유전자의 발현연구로서 apoptosis 저해 단백질인 bcl-2 유전자를 곤충세포에 형질전환시킨 후 이 단백질이 한시적으로 발현되는 것을 western blot분석법으로 확인하였으며 apoptosis가 지연된 곤충세포주의 개발이 가능하다는 결론을 보였다.