Studies on the mechanism of action of ionizing radiations. VIII. Effect of hydrogen peroxide on cell metabolism, enzymes and proteins

1952 ◽  
Vol 41 (1) ◽  
pp. 188-202 ◽  
Author(s):  
E.S.Guzman Barron ◽  
Louise Seki ◽  
Phyllis Johnson
Keyword(s):  
Hydrogen Peroxide ◽  
Mechanism Of Action ◽  
Cell Metabolism ◽  
Metabolism Enzymes ◽  
Ionizing Radiations

Requirements of intracellular iron for the mechanism of action of bleomycin and hydrogen peroxide.

1991 ◽  
Vol 43 (2-3) ◽  
pp. 456 ◽  
Author(s):  
Kimette Radtke ◽  
Robert Byrnes ◽  
Frank Lornitzo ◽  
William E. Antholine ◽  
David H. Petering
Keyword(s):  
Hydrogen Peroxide ◽  
Mechanism Of Action ◽  
Intracellular Iron

The effects of high dose rates of ionizing radiations on solutions of iron and cerium salts

1960 ◽  
Vol 255 (1283) ◽  
pp. 490-508 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Dose Rate ◽  
Ferrous Sulphate ◽  
High Dose ◽  
Oh Radicals ◽  
Dose Rates ◽  
Reaction Zones ◽  
Constant Dose ◽  
Ceric Sulphate ◽  
Ionizing Radiations

The electron beam generated by a 15 MeV linear accelerator has been employed to induce reactions in aerated aqueous solutions of 1 to 25 mM ferrous sulphate, and of 0⋅1 to 1 mM ceric sulphate. The radiation was delivered in pulses of 1⋅3 μ s duration and over a range of dose rates from 0⋅5 to 20000 rads/pulse. Radiation yields at constant dose rate were compared with the aid of a chemical dose monitor. A system of two thin, widely spaced, irradiation vessels was employed to determine the variation of yield of any one system over successive known ranges of dose rate. The yield of ferric sulphate in the iron system was found to decrease with increasing dose rate in the range 0⋅01 to 10 krads/pulse by an overall factor of 0⋅85, and was appreciably dependent on the initial concentrations of dissolved oxygen and of ferrous sulphate at high dose rates. Yields of hydrogen and of hydrogen peroxide were practically independent of dose rate. The observations have been interpreted on the basis of inter-radical reactions which occur when the reaction zones of neighbouring clusters overlap. The following reactions can account for all the data: OH + Fe 2+ → Fe 3+ + OH ¯ , (1) H + O 2 → HO 2 , (2) H + OH → H 2 O. (7) The values k 1 / k 7 = 0⋅0062, and k 2 / k 7 = 0⋅22 are reasonably consistent with the observations. In the ceric sulphate system the yield of cerous sulphate increases progressively over the range 0⋅01 to 10 krads/pulse by an overall factor of 1⋅4. The data accord with the view that at high dose rates OH radicals react with them selves ultimately to form hydrogen peroxide, in competition with their normal reaction with cerous sulphate.

scholarly journals Indirect cytotoxicity of a 35% hydrogen peroxide bleaching gel on cultured odontoblast-like cells

2009 ◽  
Vol 20 (4) ◽  
pp. 267-274 ◽  
Author(s):  
Cármen Regina Coldebella ◽  
Ana Paula Dias Ribeiro ◽  
Nancy Tomoko Sacono ◽  
Flávia Zardo Trindade ◽  
Josimeri Hebling ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Morphology ◽  
Total Protein ◽  
Cell Metabolism ◽  
Control Group ◽  
Bleaching Agent ◽  
Morphological Alterations ◽  
Peroxide Bleaching ◽  
Cytopathic Effects ◽  
Halogen Light

The aim of this study was to evaluate the trans-enamel and trans-dentinal effects of a 35% hydrogen peroxide (H2O2) bleaching gel on odontoblast-like cells. Enamel/dentin discs obtained from bovine incisors were mounted in artificial pulp chambers (APCs). Three groups were formed: G1- 35% H2O2; G2- 35% H2O2 + halogen light application; G3- control. The treatments were repeated 5 times and the APCs were incubated for 12 h. Then, the extract was collected and applied for 24 h on the cells. Cell metabolism, total protein dosage and cell morphology were evaluated. Cell metabolism decreased by 62.09% and 61.83% in G1 and G2, respectively. The depression of cell metabolism was statistically significant when G1 and G2 were compared to G3. Total protein dosage decreased by 93.13% and 91.80% in G1 and G2, respectively. The cells in G1 and G2 exhibited significant morphological alterations after contact with the extracts. Regardless of halogen light application, the extracts caused significantly more intense cytopathic effects compared to the control group. After 5 consecutive applications of a 35% H2O2 bleaching agent, either catalyzed or not by halogen light, products of gel degradation were capable to diffuse through enamel and dentin causing toxic effects to the cells.

scholarly journals THE RELATIONSHIP OF HYDROGEN PEROXIDE TO THE INHIBITION OF THE GLYOXALASE ACTIVITY OF INTACT ERYTHROCYTES BY X-RADIATION

1958 ◽  
Vol 41 (4) ◽  
pp. 737-753 ◽  
Author(s):  
S. J. Klebanoff
Keyword(s):  
Hydrogen Peroxide ◽  
Plasma Glucose ◽  
Physiological Saline ◽  
Inhibitory Effect ◽  
Enzyme Systems ◽  
Low Concentrations ◽  
X Irradiation ◽  
Ionizing Radiations ◽  
Relationship Of

The x-irradiation of a dilute suspension of erythrocytes results in a decrease in the glyoxalase activity of the cells as a result of a fall in the reduced glutathione level. The present paper deals with the possible role of H2O2 in this reaction. The addition of intact erythrocytes to physiological saline previously irradiated with 150,000 r or 225,000 r results in a fall in the glyoxalase activity of the cells. The inhibition is prevented by the preincubation of the irradiated saline with catalase and is reversed by the addition of plasma, glucose, adenosine, and inosine to the cell suspension. An inhibition of the glyoxalase activity is also produced by the addition of H2O2 to the suspension of erythrocytes. The inhibitory effect of H2O2 can be prevented and largely reversed by plasma, glucose, adenosine, and inosine. Methylglyoxal is also protective under these conditions. Hydrogen peroxide formed continuously and in low concentrations by enzyme systems appears to be more effective than added H2O2 in inhibiting the glyoxalase system. The inhibition by H2O2-producing enzyme systems is minimized by the addition of catalase, plasma, glucose, methylglyoxal, and to a lesser extent, by adenosine and inosine, and is accentuated by the addition of sodium azide. The results are discussed in relation to the role of H2O2 and catalase in the toxicity of ionizing radiations.

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