• Title/Summary/Keyword: peroxide

Search Result 3,780, Processing Time 0.032 seconds

THE EFFECT OF REMOVAL OF RESIDUAL PEROXIDE ON THE SHEAR BOND STRENGTH AND THE FRACTURE MODE OF COMPOSITE RESIN-ENAMEL AFTER TOOTH BLEACHING (생활치 표백술 후 수종의 자유 산소기 제거제 처리가 복합 레진-법랑질 전단 접착 강도 및 파절 양상에 미치는 영향)

  • 임경란;금기연;김애리;장수미
    • Restorative Dentistry and Endodontics
    • /
    • v.26 no.5
    • /
    • pp.399-408
    • /
    • 2001
  • Tooth bleaching has been prevailing recently for its ability to recover the color and shape of natural teeth without reduction of tooth material. However, it has been reported that bleaching procedure adversely affects the adhesive bond strength of composite resin to tooth. At the same time the bond strength was reported to be regained by application of some chemical agents. The purpose of this in vitro study was to investigate the effect of the removal of residual peroxide on the composite- enamel adhesion and also evaluated fracture mode between resin and enamel after bleaching. Sixty extracted human anterior and premolars teeth were divided into 5 groups and bleached by combined technique using of office bleaching with 35 % hydrogen peroxide and matrix bleaching with 10% carbamide peroxide for 4 weeks. After bleaching, the labial surfaces of each tooth were treated with catalase, 70% ethyl alcohol, distilled water and filled with composite resin. Shear bond strength was tested and the fractured surfaces were also examined with SEM. Analysis revealed significantly higher bond strength values. (p<0.05) for catalase-treated specimens, but water-treated specimens showed reduction of bond strength, alcohol- treated specimens had medium value between the two groups(p<0.05). The fracture mode was shown that the catalase group and the alcohol group had cohesive failure but the water sprayed group had adhesive failure. It was concluded that the peroxide residues in tooth after bleaching seems to be removed by gradual diffusion and the free radical oxygen from peroxide prevents polymerization by combining catalyst in the resin monomer. Therefore it may be possible to eliminate the adverse effect on the adhesion of composite resin to enamel after bleaching by using water displacement solution or dentin bonding agent including it for effective removal of residual peroxide.

  • PDF

Effects of $\beta$-Mercaptoethanol and Hydrogen Peroxide on Enzymatic Conversion of Human Proinsulin to Insulin

  • Son, Young-Jin;Kim, Chang-Kyu;Choi, Byoung-Taek;Park, Yong-Cheol;Seo, Jin-Ho
    • Journal of Microbiology and Biotechnology
    • /
    • v.18 no.5
    • /
    • pp.983-989
    • /
    • 2008
  • Human insulin is a hormone well-known to regulate the blood glucose level. Recombinant preproinsulin, a precursor of authentic insulin, is typically produced in E. coli as an inactive inclusion body, the solubilization of which needs the addition of reducing agents such as $\beta$-mercaptoethanol. To make authentic insulin, recombinant preproinsulin is modified enzymatically by trypsin and carboxypeptidase B. The effects of $\beta$-mercaptoethanol on the formation of human insulin derivatives were investigated in the enzymatic modification by using commercially available human proinsulin as a substrate. Addition of 1 mM $\beta$-mercaptoethanol induced the formation of various insulin derivatives. Among them, the second major one, impurity 3, was found to be identical to the insulin B chain fragment from $Phe_1$ to $Glu_{21}$. Minimization of the formation of insulin derivatives and concomitant improvement of the production yield of human insulin were achieved by the addition of hydrogen peroxide. Hydrogen peroxide bound with $\beta$-mercaptoethanol and thereby reduced the negative effects of $\beta$-mercaptoethanol considerably. Elimination of the impurity 3 and other derivatives by the addition of over 10 mM hydrogen peroxide in the presence of $\beta$-mercaptoethanolled to a 1.3-fold increase in the recovery efficiency of insulin, compared with those for the case without hydrogen peroxide. The positive effects of hydrogen peroxide were also confirmed with recombinant human preproinsulin expressed in recombinant E. coli as an inclusion body.

Protective Effect of Ursolic Acid from Corni fructus on the Hydrogen Peroxide-induced Damage of HEI-OC1 Auditory Cells (산수유로부터 추출한 ursolic acid가 과산화수소로 손상된 HEI-OC1 청각세포보호에 미치는 영향)

  • Yu, Hyeon-Hee;Seo, Se-Jeong;Hur, Jong-Moon;Park, Rae-Kil;So, Hong-Seob;Jeon, Byung-Hun;You, Yong-Ouk
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.20 no.6
    • /
    • pp.1524-1529
    • /
    • 2006
  • The fruits of Cornus officinalis have been used in traditional Oriental medicine for treatment of inner ear diseases, such as tinnitus and hearing loss. In the present study, we showed that the ursolic acid obtained from Corni fructus protected HEI-OC1 auditory cells from hydrogen peroxide cytotoxicity in a dose-dependent fashion. In addition, to investigate the protection mechanism of ursolic acid on hydrogen peroxide cytotoxicity toward HEI-OC1, we measured the effects of ursolic acid on lipid peroxidation and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) in hydrogen peroxide treated cells. Ursolic acid (0.05 - 2 ${\mu}g/ml$) had protective effect against the hydrogen peroxide-induced HEI-OC1 cell damage and reduced lipid peroxidation in a dose-dependent manner. Pre-treatment with ursolic acid significantly attenuated the decrease in activities of CAT and GPX, but SOD activity was not affected by the ursolic acid or hydrogen peroxide. These results indicate that ursolic acid protects hydrogen peroxide-induced HEI-OC1 cell damage through inhibition of lipid peroxidation and induce the antioxidant enzymes CAT and GPX.

Effects of Red Ginseng-Ejung-tang on Nitric Oxide and Hydrogen Peroxide Production in LPS-induced Mouse Macrophages RAW 264.7 (홍삼이중탕(紅蔘理中湯)이 LPS로 유발된 마우스 대식세포 RAW 264.7의 nitric oxide 및 hydrogen peroxide 생성에 미치는 영향)

  • Lee, Ji-Young;Park, Wan-Su
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.25 no.2
    • /
    • pp.294-299
    • /
    • 2011
  • The purpose of this study is to investigate effects of Red Ginseng-Ejung-tang (RE) on nitric oxide (NO) and hydrogen peroxide production in RAW 264.7 mouse macrophages induced by lipopolysaccharide (LPS). Cell viability was measured by modified MTT assay. NO production was measured by Griess reagent assay. Hydrogen peroxide production was measured by dihydrorhodamine 123 (DHR) assay. RE did not show cell toxicity against RAW 264.7 for 24 hr incubation at the concentrations of 10, 25, 50, 100, and $200{\mu}g/mL$ in RAW 264.7. RE significantly inhibited NO production for 24 hr incubation at the concentrations of 10, 25, 50, and $100{\mu}g/mL$ in RAW 264.7 (P < 0.05). RE significantly inhibited the LPS-induced production of NO for 24 hr incubation at the concentrations of 10, 25, 50, and $100{\mu}g/mL$ in RAW 264.7 (P < 0.05). RE significantly inhibited the LPS-induced production of hydrogen peroxide for 16, 24, 40, 48, 64, and 72 hr incubation at the concentrations of 50, 100, and $200{\mu}g/mL$ in RAW 264.7 (P < 0.05). These results suggest that RE has anti-inflammatory property related with its inhibition of NO and hydrogen peroxide production in LPS-induced macrophages.

Performance Evaluation of Ethanol Blended Hydrogen Peroxide Thrusters (에탄올 블렌딩한 과산화수소 추력기의 성능평가)

  • Lee, Jeong-Sub;Kwon, Se-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2012.05a
    • /
    • pp.100-103
    • /
    • 2012
  • The blending method that is an addition of small quantity of fuel was used to increase the performance of green propellant thruster. 90 wt.% hydrogen peroxide as a green propellant was selected, and ethanol was used as a blended fuel. The o/f ratio was chosen as 50 which has higher theoretical performance than 98 wt.% hydrogen peroxide. The chamber temperature of blended hydrogen peroxide was higher than adiabatic chamber temperature of hydrogen peroxide. Therefore, performance can be improved by ethanol blending. Several catalyst and its support were compared to find appropriate catalyst for decomposition and combustion of ethanol blended hydrogen peroxide. As a experimental results, Pt was suitable, but $MnO_2$ had a chamber instability when it was reused. The ${\alpha}-Al_2O_3$ which is high heat-resistant support showed very unstable performance in both Pt and $MnO_2$ catalyst since it has low decomposition performance.

  • PDF

Enzymatic Hydrolysis of Pre-treated Ulva pertusa with Alkaline Peroxide (구멍갈파래의 알칼리 과산화수소 전처리 및 효소 가수분해 특성)

  • Yoon, Byung-Tae;Kim, Young-Wun;Chung, Keun-Wo;Kim, Jin-Seog
    • Applied Chemistry for Engineering
    • /
    • v.22 no.3
    • /
    • pp.336-339
    • /
    • 2011
  • Algae is an abundant and potential fermentation substrate. The enzymatic hydrolysis of algae was investigated by pre-treating an alkaline hydrogen peroxide with commercial cellulase and viscozyme. Algae used in this study was the Ulva pertusa. The evaluated response was the yield of released glucose after the enzymatic hydrolysis. Alkaline hydrogen peroxide containing mixtures of 1 wt% hydrogen peroxide and 1~1.75 wt% sodium hydroxide was also used. The results show that the highest glucose conversion was obtained for Ulva pertusa using 5 wt% hydrogen peroxide at $60^{\circ}C$ for 3 h. The required amount of enzymes after the pre-treatment with alkaline hydrogen peroxide were reduced by far compared to that of untreated Ulva pertusa. Also, the amount of glucose that is released during the enzymatic hydrolysis was increased.

Role of Nitric Oxide as an Antioxidant in the Defense of Gastric Cells (위선세포의 항산화 방어기전으로의 Nitric Oxide의 역할)

  • Kim, Hye-Young;Lee, Eun-Joo;Kim, Kyung-Hwan
    • The Korean Journal of Pharmacology
    • /
    • v.32 no.3
    • /
    • pp.389-397
    • /
    • 1996
  • Gatric mucosa is exposed to toxic, reactive oxygen species generated within the lumen. Nitric oxide protected acetaminophen-induced hepatotoxicity by maintaining glutathione homeostasis. The present study examined the role of nitric oxide in mediating hydrogen peroxide - induced damage to gastric cells. Hydrogen peroxide was generated by glucose oxidase acting on ${\beta}-D-glucose$. L-arginine, $N^G-nitro-L-arginine$ methyl ester, or $N^G-nitro-L-arginine$ were treated to the cells with glucose/glucose oxidase. Lipid peroxidation and nitrite release and cellular content of glutathione were determined. As a result, dose - dependent increase in lipid peroxide production as well as dose - dependent decrease in nitrite release and cellular glutathione content were observed in glucose/glucose oxidase - treated cells. Pretreatment of L-arginine, a substrate for nitric oxide synthase, prevented the increase of lipid peroxide production and the reduction of nitrite release as well as glutathione content. Inhibitors of nitric oxide synthase such as $N^G-nitro-L-arginine$ methyl ester and $N^G-nitro-L-arginine$ did not protect hydrogen peroxide - induced cell damage. In conclusion, nitric oxide protects gestric cells from hydrogen peroxide possibly by inhibiting lipid peroxidation and by preserving cellular glutathione stores.

  • PDF

A QUANTITATIVE STUDY ON THE DEGRADING EFFECT OF THE VARIOUS IRRIGATING AGENTS IN THE ELIMINATION OF RESIDUAL HYDROGEN PEROXIDE FOLLOWING WALKING BLEACHING (무수치 표백술 후 잔존 과산화수소수 제거를 위한 수종의 치수강 세척제의 효과에 관한 정량적 연구)

  • Kum, Kee-Yeon;Han, Won-Sup;Jung, Il-Young;Lee, Seung-Jong;Lee, Chan-Young;Oh, Byung-Hoon
    • Restorative Dentistry and Endodontics
    • /
    • v.23 no.2
    • /
    • pp.656-669
    • /
    • 1998
  • Hydrogen peroxide at high concentration during walking bleaching may cause damage to the tooth structure and to the surrounding periodontal tissues and may develop external root resorption. Clinically, It is so important to find a method of prevention or minimization of these complications. The efficacy of various chamber-irrigating agents to eliminate residual hydrogen peroxide after walking bleaching was examined and compared with water rinse in this study. Extracted human 46 premolars without any cementoenamel junction defects were treated endodontically and based with IRM to 1 mm below CEJ and totally bleached 3 times for each tooth with 30% hydrogen peroxide and sodium perborate. Upon completion of the 3rd walking bleaching procedure, the cervical portion and pulp chamber of each group of teeth were irrigated with catalase, 70% ethylalcohol, acetone, and distilled water. And then, a radicular hydrogen peroxide penetration was measured with spectrophotometer immediately after each bleaching and following treatment with each chamber-irrigating agents, and the significance of their eliminating efficacy of residual hydrogen peroxide was analyzed by Kruskal-Wallis test. The results were obtained as follows. 1. Cervical root penetration of hydrogen peroxide was increased as the bleaching procedure was repeated(P<.01). 2. The most effective irrigant that removed residual hydrogen peroxide was the catalase, and the least effective one was water rinsing (P<.01).; there was no significant difference between the acetone and ethanol group. 3. The Irrigation with antioxidant enzyme or water-displacement solutions can eliminate residual oxygen radicals from the pulp chamber effectively after walking bleaching. So, these agents can reduce adverse effects such as cervical external resorption and periapical inflammation and prevent residual $O_2$ from impeding composite resin polymerization, thus increase the bonding strength of composite resin. This, in turn reduces microleakage and discoloration of the esthetic restoration, extending its service-life.

  • PDF

Photo or Solar Ferrioxalate Disinfection Technology without External Hydrogen Peroxide Supply

  • Cho, Min;Jeong, Joon-Seon;Kim, Jae-Eun;Yoon, Je-Yong
    • Environmental Engineering Research
    • /
    • v.12 no.5
    • /
    • pp.238-243
    • /
    • 2007
  • The Fenton reaction, which refers to the reaction between ferrous ions and hydrogen peroxide to produce the OH radical, has not been widely applied to the disinfection of microorganisms despite being economic and environmentally friendly. Cho et al. have previously proposed the neutral photo ferrioxalate system as a solution to the problems posed by the Fenton reaction in acidic conditions, but this system still requires an external hydrogen peroxide supply. In the present study, we developed a simple disinfection technology using the photo or solar ferrioxalate reaction without the need for an external hydrogen peroxide supply. E. coli was employed as the indicating microorganism. The study results demonstrated the effectiveness of the photo ferrioxalate system in inactivating E. coli without any external hydrogen peroxide supply, as long as dissolved oxygen is supplied. Furthermore, the solar ferrioxalate system achieved faster inactivation of E. coli than an artificial light source at similar irradiance.