Systems containing hydrogen peroxide at high concentrations Communication 17. Solubility isotherms and solid phases in the system Ba(OH)2-H2O2-H2O

1959 ◽  
Vol 8 (1) ◽  
pp. 7-14
Author(s):  
S. Z. Makarov ◽  
N. K. Grigor'eva
Keyword(s):  
Hydrogen Peroxide ◽  
Solubility Isotherms ◽  
Solid Phases ◽  
High Concentrations

Effects of hydrogen peroxide and hypochlorite on membrane potential of mitochondria in situ in rat heart cells

1991 ◽  
Vol 69 (11) ◽  
pp. 1705-1712 ◽  
Author(s):  
Noburu Konno ◽  
K. J. Kako
Keyword(s):  
Hydrogen Peroxide ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Rat Heart ◽  
Mitochondrial Membrane ◽  
Isolated Rat Heart ◽  
Heart Mitochondria ◽  
High Concentrations ◽  
Isolated Rat

Hydrogen peroxide (H2O2) and hypochlorite (HOCl) cause a variety of cellular dysfunctions. In this study we examined the effects of these agents on the electrical potential gradient across the inner membrane of mitochondria in situ in isolated rat heart myocytes. Myocytes were prepared by collagenase digestion and incubated in the presence of H2O2 or HOCl. Transmembrane electrical gradients were measured by distribution of [3H]triphenylmethylphosphonium+, a lipophilic cation. The particulate fraction was separated from the cytosolic compartment first by permeabilization using digitonin, followed by rapid centrifugal sedimentation through a bromododecane layer. We found that the mitochondrial membrane potential (161 ± 7 mV, negative inside) was relatively well maintained under oxidant stress, i.e., the potential was decreased only at high concentrations of HOCl and H2O2 and gradually with time. The membrane potential of isolated rat heart mitochondria was affected similarly by H2O2 and HOCl in a concentration- and time-dependent manner. High concentrations of oxidants also reduced the cellular ATP level but did not significantly change the matrix volume. When the extra-mitochondrial free calcium concentration was increased in permeabilized myocytes, the transmembrane potential was decreased proportionally, and this decrease was potentiated further by H2O2. These results support the view that heart mitochondria are equipped with well-developed defense mechanisms against oxidants, but the action of H2O2 on the transmembrane electrical gradient is exacerbated by an increase in cytosolic calcium. Keywords: ATP, calcium, cardiomyocyte, cell defense, mitochondrial membrane potential, oxidant, triphenylmethylphosphonium.

scholarly journals Physical constraints of bath treatments of Atlantic salmon (Salmo salar) with a sea lice burden (Copepoda: Caligidae)

2000 ◽  
Vol 69 (1-2) ◽  
pp. 129-136 ◽  
Author(s):  
James W. Treasure ◽  
Andrew Gran ◽  
Paul J. Davi
Keyword(s):  
Hydrogen Peroxide ◽  
Atlantic Salmon ◽  
Water Exchange ◽  
Adverse Reactions ◽  
Sea Lice ◽  
Chemical Marker ◽  
Physical Constraints ◽  
Bath Application ◽  
End Of Treatment ◽  
High Concentrations

Licensed medicines available in the U.K. for treating Atlantic salmon infested with sea lice, dichlorvos, azamethiphos, and hydrogen peroxide, can only be administered by bath application. Adverse reactions have been reported to bath treatments including mortalities, inappetance, reduction in growth and reduced louse sensitivity to dichlorvos. The physical constraints of bath treatments are examined and improvements recommended. Oxygen saturation was adequate during treatments but declined rapidly when the tarpaulin was removed. A chemical marker dispersed uniformally both horizontally and vertically in a cage within 5 mins of dispensing indicating dispersal of a medicine is rapid and adequate during treatment. The range in enclosed volumes in 86 treatments was 46 to 146% of theoretical, suggesting potential toxicity due to high concentrations at low volumes and the risk of reduced sensitivity at high volumes. Residual concentrations of hydrogen peroxide varied from 50 to 400 ppm from 5 to 15 mins after the tarpaulin was removed. Water exchange should be encouraged by aerating the cage and flushing at the end of treatment.

scholarly journals Antioxidant Protection by American Ginseng in Pancreatic ß-Cells

2008 ◽  
Vol 36 (05) ◽  
pp. 981-988 ◽  
Author(s):  
Elaine Lin ◽  
Yong Wang ◽  
Sangeeta Mehendale ◽  
Shi Sun ◽  
Chong-Zhi Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
American Ginseng ◽  
Antioxidant Protection ◽  
Ginsenoside Re ◽  
Peripheral Tissues ◽  
Glucose Levels ◽  
Reduce Blood Glucose ◽  
Dichlorofluorescin Diacetate ◽  
High Concentrations

Hyperglycemia in diabetic conditions may cause oxidative stress in pancreatic ß-cells, leading to their dysfunction and insulin resistance within peripheral tissues. Previous studies suggest that American ginseng berry extract may have hypoglycemic effects, as well as offer antioxidant protection. We examined effects of American ginseng berry extract and ginsenoside Re in a pancreatic ß-cell line, MIN-6, to determine if these two properties are related. Cells were exposed to oxidative stress via hydrogen peroxide incubation and oxidative stress was measured by oxidation of 2′,7′-dichlorofluorescin diacetate. These cells showed a concentration-related response to hydrogen peroxide at 100–500 μM. In acute conditions where cells were treated with the extract for 10 min, we observed reduced oxidant injury suggesting direct scavenging effects. Chronic incubation of cells with the extract for 48 hours also demonstrated attenuation of oxidative stress. At high concentrations, Re showed a mild antioxidant effect in MIN-6 cells. Our insulin release observations also showed that the extract may help to increase insulin secretions from the cells. Our data suggest that the observed ability of ginseng to reduce blood glucose levels may be linked to its antioxidant effects on pancreatic ß-cells.

scholarly journals Morphological Changes inEscherichia coliCells Exposed to Low or High Concentrations of Hydrogen Peroxide

1989 ◽  
Vol 33 (12) ◽  
pp. 991-1000 ◽  
Author(s):  
Giorgio Brandi ◽  
Mara Fiorani ◽  
Cinzia Pierotti ◽  
Amedeo Albano ◽  
Flaminio Cattabeni ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Morphological Changes ◽  
High Concentrations

HYDROGEN PEROXIDE AND ITS ANALOGUES: III. ABSORPTION SPECTRUM OF HYDROGEN AND DEUTERIUM PEROXIDES IN THE NEAR ULTRAVIOLET

1951 ◽  
Vol 29 (6) ◽  
pp. 490-493 ◽  
Author(s):  
M. K. Phibbs ◽  
Paul A. Giguère
Keyword(s):  
Hydrogen Peroxide ◽  
Absorption Spectrum ◽  
Ultraviolet Light ◽  
Heavy Water ◽  
Zero Point ◽  
Zero Point Energy ◽  
Point Energy ◽  
Near Ultraviolet ◽  
The Difference ◽  
High Concentrations

The absorption of ultraviolet light between 3000 and 4000 Å by solutions of hydrogen peroxide in water and of deuterium peroxide in heavy water has been measured at various concentrations. Both peroxides show slight but real deviations from Beer's law at high concentrations. Substitution of hydrogen by deuterium shifts the absorption continuum by about 390 cm.−1 towards shorter wave lengths. This shift is of the same order as that calculated from the difference in zero-point energy of the two isotopic molecules.

The role of catalase in hydrogen peroxide resistance in fission yeast Schizosaccharomyces pombe

1999 ◽  
Vol 45 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Norihiro Mutoh ◽  
Chiaki W Nakagawa ◽  
Kenichiro Yamada
Keyword(s):  
Hydrogen Peroxide ◽  
Schizosaccharomyces Pombe ◽  
Catalase Activity ◽  
Parent Strain ◽  
Normal Growth ◽  
Wild Type ◽  
Catalase Gene ◽  
In The Wild ◽  
High Concentrations

The role of catalase in hydrogen peroxide resistance in Schizosaccharomyces pombe was investigated. A catalase gene disruptant completely lacking catalase activity is more sensitive to hydrogen peroxide than the parent strain. The mutant does not acquire hydrogen peroxide resistance by osmotic stress, a treatment that induces catalase activity in the wild-type cells. The growth rate of the disruptant is not different from that of the parent strain. Additionally, transformed cells that overexpress the catalase activity are more resistant to hydrogen peroxide than wild-type cells with normal catalase activity. These results indicate that the catalase of S. pombe plays an important role in resistance to high concentrations of hydrogen peroxide but offers little in the way of protection from the hydrogen peroxide generated in small amounts under normal growth conditions.Key words: catalase, gene disruption, induced hydrogen peroxide resistance, overexpression, Schizosaccharomyces pombe.

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