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Toxic Metals Data

Life Flow One
The Solution For Heart Disease

by
Karl Loren

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HealthGate Documents

Record 1 from database: MEDLINE
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Title

Role of Fenton chemistry in thiol-induced toxicity and apoptosis.

Author

Held KD; Sylvester FC; Hopcia KL; Biaglow JE

Address

Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, 02114, USA.

Source

Radiat Res, 1996 May, 145:5, 542-53

Abstract

Under certain conditions, many radioprotective thiols can be toxic, causing loss of colony-forming ability in cultured mammalian cells in a biphasic fashion whereby the thiols are not toxic at high or low concentrations of the drug, but cause decreased clonogenicity at intermediate (0.2-1.0 mM) drug levels. This symposium paper summarizes our studies using dithiothreitol (DTT) as a model thiol to demonstrate the role of Fenton chemistry in thiol toxicity. The toxicity of DTT in V79 cells has several characteristics: it is dependent on the medium used during exposure of cells to the drug; the toxicity is decreased or prevented by addition of catalase exogenously, but superoxide dismutase has no effect; the toxicity is increased by addition of copper, either free or derived from ceruloplasmin in serum; and the toxicity can be modified intracellularly by altering glucose availability or pentose cycle activity. Thus the data are consistent with a mechanism whereby DTT oxidation produces H2O2 in a reaction catalyzed by metals, predominantly copper, followed by reaction of H2O2 in a metal-catalyzed Fenton reaction to produce the ultimate toxic species, .OH. Studies comparing 12 thiols have shown that the magnitude of cell killing and pattern of dependence on thiol concentration vary among the different agents, with the toxicity depending on the interplay between the rates of two reactions: thiol oxidation and the reaction between the thiol and the H2O2 produced during the thiol oxidation. The addition of other metals, e.g. Zn2+, and metal chelators, e.g. EDTA, can also alter DTT toxicity by altering the rates of thiol oxidation or the Fenton reaction. Recent studies have shown that in certain cell lines thiols can also cause apoptosis in a biphasic pattern, with little apoptosis at low or high drug concentrations but greatly increased apoptosis levels at intermediate (approximately 3 mM) thiol concentrations. There appears to be a good correlation between those thiols that cause loss of clonogenicity and those that induce apoptosis, suggesting similar mechanisms may be involved in both end points. However, thiol-induced apoptosis is not prevented by addition of exogenous catalase. These observations are discussed in relation to the possible role of Fenton chemistry in induction of apoptosis by thiols.

Language of Publication

English

Unique Identifier

96198949

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MeSH Heading (Major)

Apoptosis|*DE; Cell Survival|*DE; Hydrogen Peroxide|*; Iron|*; Sulfhydryl Compounds|*PD/TO

MeSH Heading

Animal; Cell Line; Chelating Agents|PD; Dithiothreitol|PD/TO; Human; Hydroxyl Radical; Metals|PD; Support, U.S. Gov't, P.H.S.

Publication Type

JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL

ISSN

0033-7587

Country of Publication

UNITED STATES

Record 2 from database: MEDLINE
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Title

Cytokine production by human airway epithelial cells after exposure to an air pollution particle is metal-dependent.

Author

Carter JD; Ghio AJ; Samet JM; Devlin RB

Address

National Health and Environmental Effects Research Laboratory, Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.

Source

Toxicol Appl Pharmacol, 1997 Oct, 146:2, 180-8

Abstract

Despite the many epidemiological studies supporting the contention that ambient air pollution particles can adversely affect human health, there is no clear agreement as to a biologically plausible mechanism which can explain the acute mortality and morbidity associated with exposure to particles less than 10 &mgr;m in size. We tested the hypothesis that metals present in an air pollution particle can induce the synthesis and expression of the inflammatory cytokines IL-8, IL-6, and TNFalpha. A residual oil fly ash (ROFA) containing the transition metals vanadium, nickel, and iron was used as a model emission source air pollution particle. Normal human bronchial epithelial (NHBE) cells were exposed for either 2 or 24 hr to 0, 5, 50, or 200 microg/ml ROFA. Concentrations of IL-8, IL-6, and TNF-alpha proteins were measured with commercially available ELISA kits. mRNA for these same cytokines was quantified by RT-PCR. NHBE cells exposed to ROFA produced significant amounts of IL-8, IL-6, and TNF, as well as mRNAs coding for these cytokines. Cytokine production was inhibited by the inclusion of either the metal chelator deferoxamine (1.0 mM) or the free radical scavenger dimethylthiourea (1.0 mM). In addition, vanadium containing compounds, but not iron or nickel sulfates, mimicked the effects of intact ROFA. These results demonstrate that metals present in ROFA may be responsible for production and release of inflammatory mediators by the respiratory tract epithelium and suggest that these mediators may contribute to the toxic effects of particulate air pollutants reported in epidemiology studies. Copyright 1997 Academic Press.

Language of Publication

English

Unique Identifier

98008957

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MeSH Heading (Major)

Air Pollutants, Occupational|*AE; Bronchi|*DE/ME; Cytokines|*BI/GE; Metals|*AE

MeSH Heading

Carbon|AE; Cells, Cultured; Chelating Agents|PD; Deferoxamine|PD; Epithelial Cells|DE/ME; Free Radical Scavengers|PD; Human; Interleukin-6|BI/GE; Interleukin-8|BI/GE; Iron|AE; Nickel|AE; Particle Size; RNA, Messenger|AN/GE; Thiourea|AA/PD; Tumor Necrosis Factor|BI/GE; Vanadium|AE

Publication Type

JOURNAL ARTICLE

ISSN

0041-008X

Country of Publication

UNITED STATES

Record 3 from database: MEDLINE
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Title

The protective role of ceruloplasmin against the activity of free radicals in brain ischaemia.

Author

I…Áecka J

Address

Katedra i Klinika Neurologii Akademii Medycznej w Lublinie.

Source

Ann Univ Mariae Curie Sklodowska [Med], 1996, 51:, 97-101

Abstract

Free radicals are atoms, groups of atoms or particles having on their last orbital at least one unpaired electron. This feature decides about their great chemical reactivity and lability (12, 16). To potentially toxic oxygen radicals belong: peroxidal anion radical, hydroxidal radical, hydrogen peroxide, hydroxylic radical, peroxidal lipid radical, singletal oxygen (12). The presence of free radicals in biological systems may play a role in etiopathogenesis of different illnesses. Overactivity of these compounds causes damage of tissues and bodily organs (3, 16, 18).

Language of Publication

English

Unique Identifier

98128307

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MeSH Heading (Major)

Cerebral Ischemia|*PP; Ceruloplasmin|*PH

MeSH Heading

Biological Markers|AN; Cerebral Ischemia, Transient|PP; Free Radicals|ME; Human; Metals|ME

Publication Type

JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL

ISSN

0066-2240

Country of Publication

POLAND

Record 4 from database: MEDLINE
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Title

Hemin toxicity in a human epithelioid sarcoma cell line.

Author

Braverman S; Helson C; Helson L

Address

St. Agnes Hospital, White Plains, New York 10605, USA.

Source

Anticancer Res, 1995 Sep, 15:5B, 1963-7

Abstract

The major cytotoxic component of hemin was identified as metal free protoporphyrin IX in an epithelioid sarcoma cell line (VA-ES-BJ) and a glioblastoma cell line (U-373 MG) by exposing the cell lines to the iron chelator deferoxamine, tin-protoporphyrin IX, and protoporphyrin IX. The contribution of lipid peroxidation and free radical generation to toxicity was examined using DL-buthionine-[S,R]-sulfoximine (BSO), and 21-aminosteroid (lazaroid, U74500A). Hemin caused significantly greater toxicity in VA-ES-BJ than in U-373 MG. While exogenous PpIX was more toxic than hemin in both cell lines, this toxicity was not due to iron depletion following intracellular heme formation since ferric citrate did not reverse PpIX toxicity. Pre-treatment with BSO enhanced hemin toxicity in the VA-ES-BJ cell line but not in U-373 MG, suggesting different modes of toxicity in the two cell lines. Exposure to lazaroid protected only VA-ES-BJ from protoporphyrin-induced toxicity implicating a specific sensitivity to lipid peroxidation and/or free radical generation by this cell line. These characteristics of the VA-ES-BJ cell line distinguish it from the glioblastoma and emphasize its utility for exploring cytotoxic effects of hemin and its precursors.

Language of Publication

English

Unique Identifier

96152426

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MeSH Heading (Major)

Hemin|*PD

MeSH Heading

Cell Survival|DE; Deferoxamine|PD; Human; Iron|ME; Lipid Peroxidation; Methionine Sulfoximine|AA/PD; Protoporphyrins|PD; Sarcoma|PA; Support, Non-U.S. Gov't; Tumor Cells, Cultured

Publication Type

JOURNAL ARTICLE

ISSN

0250-7005

Country of Publication

GREECE

Record 5 from database: MEDLINE
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Title

In vitro cell injury by oxidized low density lipoprotein involves lipid hydroperoxide-induced formation of alkoxyl, lipid, and peroxyl radicals.

Author

Coffey MD; Cole RA; Colles SM; Chisolm GM

Address

Department of Cell Biology, Research Insitute of The Cleveland Clinic Foundation, Ohio 44195, USA.

Source

J Clin Invest, 1995 Oct, 96:4, 1866-73

Abstract

Mounting evidence supports current theories linking lipoprotein oxidation to atherosclerosis. We sought the cellular biochemical mechanism by which oxidized LDL inflicts cell injury. Inhibitors of candidate pathways of cell death were used to treat human fibroblast target cells exposed to oxidized LDL.. Ebselen, which degrades lipid hydroperoxides, inhibited oxidized LDL toxicity, consistent with our recent report that 7 beta-hydroperoxycholesterol (7 beta-OOH chol) is the major cytotoxin of oxidized LDL. Intracellular chelation of metal ions inhibited, while preloading cells with iron enhanced, toxicity, Inhibition of oxidized LDL and 7 beta-OOH chol toxicity by 2-keto-4-thiolmethyl butyric acid, a putative alkoxyl radical scavenger and by vitamin E, probucol and diphenylphenylenediamine, putative scavengers of peroxyl radicals was consistent with the involvement of these radicals in the lethal sequence. Cell death was thus postulated to occur due to lipid peroxidation via a sequence involving lipid hydroperoxide-induced, iron-mediated formation of alkoxyl, lipid, and peroxyl radicals. Pathways involving other reactive oxygen species, new protein synthesis, or altered cholesterol metabolism were considered less likely, since putative inhibitors failed to lessen toxicity. Understanding the mechanism of cell injury by oxidized LDL and its toxic moiety, 7 beta-OOH chol, may indicate specific interventions in the cell injury believed to accompany vascular lesion development.

Language of Publication

English

Unique Identifier

96013647

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MeSH Heading (Major)

Alcohols|*ME; Lipid Peroxidation|*; Lipoproteins, LDL|*TO; Peroxides|*ME

MeSH Heading

Arachidonic Acid|ME; Atherosclerosis|ET; Azoles|PD; Cells, Cultured; Chloroquine|PD; Cholesterol|AA/ME/TO; Free Radicals; Human; Iron|PH; Organoselenium Compounds|PD; Oxidation-Reduction; Support, U.S. Gov't, P.H.S.

Publication Type

JOURNAL ARTICLE

ISSN

0021-9738

Country of Publication

UNITED STATES

Record 6 from database: MEDLINE
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Title

Heterogeneous effect of flavonoids on K+ loss and lipid peroxidation induced by oxygen-free radicals in human red cells.

Author

Maridonneau-Parini I; Braquet P; Garay RP

Address

Source

Pharmacol Res Commun, 1986 Jan, 18:1, 61-72

Abstract

Treatment of fresh erythrocytes with phenazine methosulfate, an intracellular generator of oxygen-free radicals, and diethyldithiocarbamate an inhibitor of superoxide dismutase results in membrane damage consisting in lipid peroxidation and increase in passive K+ permeability. Various flavonoids which have previously been reported to act as oxygen-free radical scavengers were tested on this erythrocyte model. Surprisingly, flavonoids did not exhibit the same effect on the oxygen free radical-stimulated K+ permeability. It was possible to classify these agents into four groups: protective (those decreasing the oxygen-free radical-stimulated K+ permeability): kaempferol, naringenin, apigenin, naringin; toxic (those increasing the deleterious effect of oxygen-free radicals): myricetin, delphinidin, quercetin; biphasic effective (characterized by opposite effects depending on the concentration): phloretin, cyanin, catechin, morin and inactive: rutin, phloridzin. In addition, a similar classification was observed when membrane lipid peroxidation was examined, i.e. kaempferol decreased lipid peroxide formation whereas myricetin enhanced it, morin exhibited a biphasic effect and rutin has no effect. The previously reported metal chelating effect of flavonoids could not totally explain the protective effect of kaempferol as was demonstrated by the partial protective effect exhibited by desferrioxamine. Moreover, this study suggests that a generation of oxygen-free radicals in red cells induced a K+ loss which probably results from membrane lipid peroxidation.

Language of Publication

English

Unique Identifier

86149588

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MeSH Heading (Major)

Bioflavonoids|*PD; Erythrocytes|DE/*ME; Lipid Peroxides|*BL; Potassium|*BL

MeSH Heading

Cell Membrane Permeability; Deferoxamine|PD; Ditiocarb|PD; Free Radicals; Human; In Vitro; Malondialdehyde|BL; Superoxide Dismutase|BL

Publication Type

JOURNAL ARTICLE

ISSN

0031-6989

Country of Publication

UNITED STATES

CAS Registry/EC Number

EC 1.15.1.1 (Superoxide Dismutase); 0 (Bioflavonoids); 0 (Free Radicals); 0 (Lipid Peroxides); 147-84-2 (Ditiocarb); 542-78-9 (Malondialdehyde); 70-51-9 (Deferoxamine); 7440-09-7 (Potassium)

Record 7 from database: MEDLINE
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Title

Structural damage to lymphocyte nuclei by H2O2 or gamma irradiation is dependent on the mechanism of OH. radical production.

Author

Allan IM; Vaughan AT; Milner AE; Lunec J; Bacon PA

Address

Department of Rheumatology, Medical School, University of Birmingham, UK.

Source

Br J Cancer, 1988 Jul, 58:1, 34-7

Abstract

Normal human lymphocytes were exposed to OH. radicals produced indirectly by exposure to H2O2 or directly by gamma irradiation. Using a flow cytometry technique to measure changes in nucleoid size, it was found that generation of OH. in each system produced a characteristic relaxation in nuclear supercoiling. Exposure of cells to H2O2 produced a metal-dependent step-wise relaxation in extracted nucleoids, while gamma irradiation induced a gradual dose-dependent increase in nucleoid size. The site-specific metal-dependent changes produced in lymphocytes incubated in H2O2 should also occur in gamma irradiated cells, but the characteristic effects on nuclear supercoiling would not be detected within the background of random DNA damage. The importance of metals in maintaining the supercoiled loop configuration of DNA within the protein matrix suggests that free radical damage at metal locations may be particularly toxic for the cell.

Language of Publication

English

Unique Identifier

89000461

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MeSH Heading (Major)

Hydrogen Peroxide|*PD; Hydroxides|*ME; Lymphocytes|DE/ME/*RE

MeSH Heading

Adult; Cell Nucleus|DE/RE; Deferoxamine|PD; Dose-Response Relationship, Radiation; DNA|DE/RE; Free Radicals; Gamma Rays; Human; Scattering, Radiation

Publication Type

JOURNAL ARTICLE

ISSN

0007-0920

Country of Publication

ENGLAND

CAS Registry/EC Number

0 (Free Radicals); 0 (Hydroxides); 70-51-9 (Deferoxamine); 7722-84-1 (Hydrogen Peroxide); 9007-49-2 (DNA)

Record 8 from database: MEDLINE
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Title

Ferritin protects endothelial cells from oxidized low density lipoprotein in vitro.

Author

Juckett MB; Balla J; Balla G; Jessurun J; Jacob HS; Vercellotti GM

Address

Department of Medicine, University of Minnesota, Minneapolis, USA.

Source

Am J Pathol, 1995 Sep, 147:3, 782-9

Abstract

Low density lipoprotein (LDL), if it becomes oxidized, develops several unique properties including the capacity to provoke endothelial cytotoxicity via metal-catalyzed free radical-mediated mechanisms. As were previously have shown that iron-catalyzed oxidant injury to endothelial cells can be attenuated by the addition of exogenous iron chelators such as the lazaroids and deferoxamine, we have examined whether the endogenous iron chelator, ferritin, might provide protection from oxidized LDL. LDL oxidized by iron-containing hemin and H2O2 is toxic to endothelial cells in a time- and dose-dependent fashion. Endothelial cell ferritin content is increased by pretreatment of cells with iron compounds or by the direct addition of exogenous apoferritin; ferritin-loaded cells are markedly resistant to the toxicity caused by oxidized LDL. Iron inactivation by ferritin depends on its ferroxidase activity. When a recombinant human ferritin heavy chain mutant, 222, which is devoid of ferroxidase activity, is added to endothelial cells, unlike the excellent protection afforded by the wild-type recombinant heavy chain, endothelial cells are not protected from oxidized LDL. To assess the in vivo relevance of our observation, we examined human coronary arteries of cardiac explants taken from patients with end-stage atherosclerosis. Large amounts of immunoreactive ferritin are focally detected in atherosclerotic lesions, specifically in the myofibroblasts, macrophages, and endothelium without a notable increase in Prussian blue-detectable iron. These findings suggest that ferritin may modulate vascular cell injury in vivo.

Language of Publication

English

Unique Identifier

95407677

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MeSH Heading (Major)

Endothelium, Vascular|CY/*DE; Ferritin|ME/*PD; Lipoproteins, LDL|AI/ME/*PD

MeSH Heading

Animal; Apoferritin|PD; Arteries; Cells, Cultured; Ceruloplasmin|ME; Coronary Arteriosclerosis|ME; Coronary Vessels|ME; Human; Immunoenzyme Techniques; Oxidation-Reduction; Swine

Publication Type

JOURNAL ARTICLE

ISSN

0002-9440

Country of Publication

UNITED STATES

Record 9 from database: MEDLINE
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Title

Reductive metabolism of nitroprusside in rat hepatocytes and human erythrocytes.

Author

Rao DN; Elguindi S; O'Brien PJ

Address

Faculty of Pharmacy, University of Toronto, Canada.

Source

Arch Biochem Biophys, 1991 Apr, 286:1, 30-7

Abstract

The metabolism of nitroprusside by hepatocytes or subcellular fractions involves a one-electron reduction of nitroprusside to the corresponding metal-nitroxyl radical. Thiol compounds also reduced nitroprusside to the metal-nitroxyl radical apparently via a thiol adduct. The nitroprusside reduction by microsomes was shown to be due to cytochrome P450 reductase as an antibody to cytochrome P450 reductase inhibits the microsomal reduction of nitroprusside, and the inhibitors of cytochrome P450 such as carbon monoxide or metyrapone had no effect. The reduction of nitroprusside by mitochondria in the presence of NADH or NADPH also produced the metal-nitroxyl radical. In hepatocytes, both mitochondria and the cytochrome P450 reductase are involved in the reduction of nitroprusside. The reductive metabolism of nitroprusside was found to produce toxic by-products, namely, free cyanide anion and hydrogen peroxide. We have also detected thiyl radicals formed in the thiol compound reduction of NP. We propose that cyanide and hydrogen peroxide are important toxic species formed in the metabolism of nitroprusside. The rate of reductive metabolism of nitroprusside by rat hepatocytes was much higher than with human erythrocytes. Therefore the major site of nitroprusside metabolism in vivo may be liver and not blood as originally proposed.

Language of Publication

English

Unique Identifier

91378306

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MeSH Heading (Major)

Erythrocytes|*ME; Liver|*ME; Microsomes, Liver|*EN; Nitroprusside|*ME; NADPH-Ferrihemoprotein Reductase|*ME

MeSH Heading

Animal; Cells, Cultured; Comparative Study; Cytosol|ME; Electron Spin Resonance Spectroscopy; Free Radicals; Human; Kinetics; Male; Mitochondria, Liver|ME; Oxidation-Reduction; Rats; Rats, Inbred Strains

Publication Type

JOURNAL ARTICLE

ISSN

0003-9861

Country of Publication

UNITED STATES

CAS Registry/EC Number

EC 1.6.2.4 (NADPH-Ferrihemoprotein Reductase); 0 (Free Radicals); 15078-28-1 (Nitroprusside)

Record 10 from database: MEDLINE
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Title

Free radical generation by selenium compounds and their prooxidant toxicity.

Author

Spallholz JE

Address

Texas Technology University, Lubbock 79404, USA.

Source

Biomed Environ Sci, 1997 Sep, 10:2-3, 260-70

Abstract

Selenium (Se) and many of its compounds are among the most toxic of nutrients. Selenium toxicity was first described in range animals in the western United States in the 1930's which consumed "selenium accumulator" plants of the genus Astragalus, Xylorrhiza, Oonopsis, and Stanleya. Selenites and selenates from the soil accumulate in these plants primarily as methylated selenium compounds and plants evolve dimethyldiselenide and dimethylselenide. Dietary selenium, primarily as selenomethionine and selenocysteine for humans fulfill the dietary requirement for selenoenzymes and proteins. In humans and animals excessive dietary selenium may be toxic. In vitro, selenium compounds such as selenite, selenium dioxide and diselenides react with thiols, such as glutathione, producing superoxide and other reactive oxygen species. This catalytic reaction of selenium compounds with thiols likely accounts for selenium toxicity to cells ex vivo and in vivo where the major glutathione producing organ, the liver, is also the major target organ of selenium toxicity. Selenium enzymes and selenoethers that do not readily form a selenide (RSe-) anion and compounds such as Ebselen where selenium is sequestered, are not toxic. Methylation of selenium by both plants and animals serves to detoxify selenium by generating methylselenides. Alternatively, full reduction of Se to elemental selenium (Se0) as done by some bacteria and the formation of heavy metal selenides such as Ag2Se or Hg2Se, results in a non-catalytic non-toxic form of selenium. This catalytic prooxidant attribute of some selenium compounds appears to account for its toxicity when such activity exceeds plant and animal methylation reactions and antioxidant defenses. This prooxidant activity may also account for cellular apoptosis and may provide a useful pharmaceutical application for selenium compounds as antibacterial, antiviral, antifungal and anticancer agents.

Language of Publication

English

Unique Identifier

97460952

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MeSH Heading (Major)

Reactive Oxygen Species|*; Selenium Compounds|*TO

MeSH Heading

Animal; Free Radicals; Human

Publication Type

JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL

ISSN

0895-3988

Country of Publication

UNITED STATES

Record 11 from database: MEDLINE
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Title

Oxidative modification of low density lipoprotein (LDL) by activated human monocytes and the cell lines U937 and HL60.

Author

Cathcart MK; Chisolm GM 3d; McNally AK; Morel DW

Address

Department of Immunology and Cancer, Research Institute of the Cleveland Clinic Foundation, Ohio 44106.

Source

In Vitro Cell Dev Biol, 1988 Oct, 24:10, 1001-8

Abstract

Human peripheral blood monocytes, upon activation, have the capacity to oxidize low density lipoprotein (LDL) and render the LDL toxic to cultured cells. Previous studies by our laboratory indicate that this process is mediated by free radicals in that it can be prevented by addition of free radical scavengers and antioxidants during the incubation of monocytes with LDL. Here we report that optimal modification of LDL by monocytes was influenced by media composition. In the absence of added metal ions, oxidation was distinctly dependent on the concentration of monocytes as well as LDL concentration. Exposure of monocytes to lipopolysaccharide or stimulation of phagocytosis by opsonized zymosan resulted in marked enhancement of LDL oxidation compared to other activating agents. After exposure to activated monocytes, lipid oxidation products in the supernatant were found both in a high molecular weight fraction containing LDL (greater than 30,000 Daltons) and in a lipoprotein-free, low molecular weight fraction (less than 30,000 Daltons), yet only the high molecular weight, LDL-containing fraction was toxic to target cells. In addition, human myelomonocytic cell lines U937 and HL60 were shown to mediate oxidation of LDL. As with monocytes, exposing these cells to opsonized zymosan caused the level of LDL oxidation to be significantly enhanced. These findings offer further insight into the mechanisms of monocyte-mediated oxidation of lipoproteins and will facilitate studies investigating the role of monocyte-modified LDL in tissue injury.

Language of Publication

English

Unique Identifier

89033610

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MeSH Heading (Major)

Lipoproteins, LDL|*ME; Monocytes|*ME; Tumor Cells, Cultured|*ME

MeSH Heading

Culture Media; Human; In Vitro; Oxidation-Reduction; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type

JOURNAL ARTICLE

ISSN

0883-8364

Country of Publication

UNITED STATES

CAS Registry/EC Number

0 (Culture Media)

Record 12 from database: MEDLINE
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Title

Effects of phytic acid on the myoglobin-t-butylhydroperoxide-catalysed oxidation of uric acid and peroxidation of erythrocyte membrane lipids.

Author

Ko KM; Godin DV

Address

Department of Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada.

Source

Mol Cell Biochem, 1991 Feb 27, 101:1, 23-9

Abstract

Phytic acid stimulated the myoglobin-t-butylhydroperoxide (TBHP)-catalysed oxidation of uric acid, but inhibited the peroxidation of erythrocyte membrane lipids induced by the same system. Butylated hydroxytoluene, a free radical chain reaction-terminating antioxidant, also suppressed the myoglobin-TBHP-induced lipid peroxidation. Moreover, phytic acid inhibited the hydroxyl radical-induced degradation of deoxyribose, but the extent of inhibition in this system was reduced by increasing the ferric ion concentration, suggesting that these effects of phytic acid on the myoglobin-TBHP-mediated oxidation are more likely attributable to its metal chelating properties rather than to a free radical scavenging action. The effectiveness of phytic acid, a naturally occurring antioxidant, in the inhibition of both iron- (as previously shown) and myoglobin-dependent lipid peroxidation suggests its possible therapeutic application as a non-toxic antioxidant for ameliorating the extent of oxy-radical-mediated myocardial ischemia/reperfusion damage.

Language of Publication

English

Unique Identifier

91186975

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MeSH Heading (Major)

Erythrocyte Membrane|*DE/ME; Membrane Lipids|*ME; Myoglobin|*PH; Peroxides|CH/*PD; Phytic Acid|*PD; Uric Acid|*ME

MeSH Heading

Human; In Vitro; Lipid Peroxidation; Oxidation-Reduction; Support, Non-U.S. Gov't

Publication Type

JOURNAL ARTICLE

ISSN

0300-8177

Country of Publication

NETHERLANDS

CAS Registry/EC Number

0 (Membrane Lipids); 0 (Myoglobin); 0 (Peroxides); 69-93-2 (Uric Acid); 75-91-2 (tert-butylhydroperoxide); 83-86-3 (Phytic Acid)

Record 13 from database: MEDLINE
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Title

Antiproliferative and DNA-scission activities of L-ascorbic acid in the presence of copper chelates.

Author

Chiou SH; Ohtsu N

Address

Source

Proc Natl Sci Counc Repub China [B], 1985 Oct, 9:4, 275-80

Abstract

L-Ascorbic acid inhibits the growth of mouse neuroblastoma and human endometrial carcinoma cells at concentrations greater than 100 microM. Under the same concentrations used in cell culture study, normal human lung fibroblasts show less sensitivity to the antiproliferative effect of ascorbate than tumor cell lines. The antitumor activity of ascorbate can be greatly potentiated by the combination with copper ions or copper chelates. The exposure of normal and tumor cells to the mixtures of ascorbate and copper chelates, especially Cu2+-o-phenanthroline and Cu2+-2,9-dimethyl-o-phenanthroline complexes, resulted in the killing of a large proportion of cell populations whereas the organic ligand portion of metal complexes was much less toxic. These copper chelates in combination with ascorbate showed different degrees of DNA-scission activities which could not be correlated with their cytotoxicities in the cell culture study. It is suggested that the primary targets of these antiproliferative agents may be on the biological sites such as cell membrane other than DNA in the nucleus which has been commonly assumed as the critical target for most free radical-generating antitumor drugs.

Language of Publication

English

Unique Identifier

86149972

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MeSH Heading (Major)

Ascorbic Acid|*PD; Cell Division|*DE; DNA, Viral|*ME

MeSH Heading

Animal; Bacteriophage lambda; Cell Line; Chelating Agents|PD; Copper|PD; Female; Human; Kinetics; Lung; Mice; Neuroblastoma; Support, Non-U.S. Gov't; Uterine Neoplasms

Publication Type

JOURNAL ARTICLE

ISSN

0253-8415

Country of Publication

TAIWAN

CAS Registry/EC Number

0 (Chelating Agents); 0 (DNA, Viral); 50-81-7 (Ascorbic Acid); 7440-50-8 (Copper)

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SUBSCRIBE:  The Wednesday Letter is a free electronic monthly newsletter written and published by Karl Loren.  You can view more than 50 back issues of this publication by clicking here.  The Wednesday Letter subscription list is maintained on a secure server, no name is ever given or sold to anyone, and it is never used except for this Newsletter.  It is automatically published on the Tuesday night just before the first Wednesday of every month.  You can subscribe to this free monthly electronic letter by entering your eMail address and name below.  You will then automatically receive a request for confirmation, sent to whatever address you have entered.  If you do NOT receive this confirmation request, then you will not be subscribed.  There may have been an error with your address and you should resubmit.  The letter is never sent twice to the same address -- so you do not have to worry about a duplicate subscription.  When you receive this confirmation request you must reply to it, or your subscription will not become active.  No one can subscribe your name, and address, without you being notified, and if you get an unwanted notice of subscription you only need to DO NOTHING and the subscription will NOT be active.

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Personal Message:  When you send a personal message to Karl Loren, you will receive a personal reply as per his instructions.  Karl pledges that every personal message will get a personal answer. When you provide your mail address, we will send you free information including our free catalog and a cassette tape lecture by Karl Loren about heart disease, no charge, by mail, even if outside the US.  You can select particular information you would like to receive, along with the free cassette tape and catalog.

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You can reach Vibrant Life in many ways, including by mail to Vibrant Life, 2808 N. Naomi St., Burbank, CA 91504.  Within the US and Canada, use the toll free number:  (800) 523-4521, the local number:  (818) 558-1799, the FAX:  (818) 558-7299, eMail to kimberly@oralchelation.com or any one of the hundreds of message forms throughout the 50 web sites.  Vibrant Life normally ships the same day we get an order.  There are message forms on each of the 100,000+ pages on this and other sites where you can communicate with Vibrant Life.  Check out our companion site, at:  http://www.oralchelation.net where Karl's 2000 page book is published.  Karl Loren is the author and webmaster for this BOOK, as well as for another web site about ORAL CHELATION.  His personal philosophical articles are at PHILOSOPHY. 

Copyright © May 20, 2008 6:26 AM by Karl Loren on behalf of Vibrant Life, ALL RIGHTS RESERVED.  Permission is granted for non-commercial downloading, copying, distribution or redistribution on two conditions:  One, that some form of copyright notice is included in every copy distributed or copied, showing the copyright belonging to Vibrant Life, Burbank, CA, at www.oralchelation.com . The second condition is that the material is not to be used for any purpose contrary to the purposes and objectives of this site.  This permission does not extend to materials on this site which are copyrighted by others.