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1.
Nature ; 583(7815): 242-248, 2020 07.
Article in English | MEDLINE | ID: mdl-32641817

ABSTRACT

Enhanced silicate rock weathering (ERW), deployable with croplands, has potential use for atmospheric carbon dioxide (CO2) removal (CDR), which is now necessary to mitigate anthropogenic climate change1. ERW also has possible co-benefits for improved food and soil security, and reduced ocean acidification2-4. Here we use an integrated performance modelling approach to make an initial techno-economic assessment for 2050, quantifying how CDR potential and costs vary among nations in relation to business-as-usual energy policies and policies consistent with limiting future warming to 2 degrees Celsius5. China, India, the USA and Brazil have great potential to help achieve average global CDR goals of 0.5 to 2 gigatonnes of carbon dioxide (CO2) per year with extraction costs of approximately US$80-180 per tonne of CO2. These goals and costs are robust, regardless of future energy policies. Deployment within existing croplands offers opportunities to align agriculture and climate policy. However, success will depend upon overcoming political and social inertia to develop regulatory and incentive frameworks. We discuss the challenges and opportunities of ERW deployment, including the potential for excess industrial silicate materials (basalt mine overburden, concrete, and iron and steel slag) to obviate the need for new mining, as well as uncertainties in soil weathering rates and land-ocean transfer of weathered products.


Subject(s)
Agriculture , Carbon Dioxide/isolation & purification , Crops, Agricultural , Geologic Sediments/chemistry , Global Warming/prevention & control , Goals , Silicates/chemistry , Atmosphere/chemistry , Brazil , China , Environmental Policy/economics , Environmental Policy/legislation & jurisprudence , Global Warming/economics , India , Iron/isolation & purification , Mining , Politics , Probability , Silicates/isolation & purification , Steel/isolation & purification , Temperature , Time Factors , United States
2.
Biometals ; 31(4): 595-604, 2018 08.
Article in English | MEDLINE | ID: mdl-29730778

ABSTRACT

Obesity is characterized by a chronic inflammatory process, with an increased volume of total adipose tissue, especially visceral, which secretes pro-inflammatory cytokines such as TNF-α and IL-6. Hepcidin (Hpc), a main iron metabolism regulator, is synthetized by an IL-6 stimuli, among others, in liver and adipose tissue, favoring an association between the inflammatory process and iron metabolism. Still there are questions remain regarding the interaction of these factors. Our aim was to study the effect of a macrophage-conditioned medium (MCM) on adipocyte cells challenged with glucose and/or iron. We studied the mRNA relative abundance of genes related to inflammation in differentiated 3T3-L1 cells challenged with Fe (40 µM), glucose (20 mM) or Fe/glucose (40 µM/20 mM) with or without MCM for 24 h. We also measured the intracellular iron levels under these conditions. Our results showed that when adipocytes were challenged with MCM, glucose and/or Fe, the intracellular iron and mRNA levels of pro-inflammatory cytokines increased. These responses were higher when all the stimuli were combined with MCM from macrophages. Thus, we showed that combined high glucose/high Fe alone or with MCM may contribute to an increase on intracellular iron and inflammatory response in 3T3-L1 differentiated cells, by increased mRNA levels of IL-6, TNF-α, MCP-1, Hpc and reducing adiponectin levels, enhancing the inflammatory processes.


Subject(s)
Adipocytes/drug effects , Inflammation/metabolism , Iron/metabolism , Obesity/metabolism , 3T3-L1 Cells , Adipocytes/metabolism , Adiponectin/genetics , Animals , Cell Differentiation/genetics , Chemokine CCL2/genetics , Culture Media, Conditioned/pharmacology , Gene Expression Regulation/drug effects , Glucose/metabolism , Hepcidins/genetics , Humans , Inflammation/genetics , Inflammation/pathology , Interleukin-6/genetics , Iron/chemistry , Macrophages/metabolism , Mice , Obesity/genetics , Obesity/pathology , Tumor Necrosis Factor-alpha/genetics
3.
Pharmacol Rep ; 69(4): 798-805, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28591668

ABSTRACT

BACKGROUND: The selective estrogen receptor modulators (SERMs) raloxifene and tamoxifen are used for the treatment of osteoporosis and cancer, respectively, in women. The impairment of both the Atrial Natriuretic Peptide (ANP) cell signaling system and the translocation of nuclear factor-kappa B (NF-kB) to the cell nucleus are associated with detrimental cardiovascular effects and inflammation. The effects of SERMs on these parameters in the cardiac tissue of estrogen-deficient rats has not been reported. METHODS: We investigated the effects of raloxifene and tamoxifen on ANP signaling, p65 NF-kB nuclear translocation, cardiac histology and contractility. Female rats were divided into five groups: control (SHAM), ovariectomized (OVX), OVX-treated 17-ß-estradiol (E), OVX-treated raloxifene (RLX) and OVX-treated tamoxifen (TAM). The treatments started 21days after ovariectomy and continued for 14days. RESULTS: Ovariectomy reduced ANP mRNA in the left atrium (LA), decreased the content of ANP protein in the LA and in plasma, and increased the level of p65 NF-kB nuclear translocation in the left ventricle. Both 17-ß-estradiol and SERMs were able to reverse these alterations, which were induced by the estrogen deficient state. The hemodynamic and cardiac structural parameters analyzed in the present work were not modified by the interventions. CONCLUSIONS: Our study demonstrates, for the first time, the additional benefits of raloxifene and tamoxifen in an estrogen-deficient state. These include the normalization of plasmatic and cardiac ANP levels and cardiac p65 NF-kB translocation. Therefore, these treatments promote cardiovascular protection and may contribute to the prevention of cardiac dysfunction observed long-term in postmenopausal women.


Subject(s)
Atrial Natriuretic Factor/metabolism , Estrogens/metabolism , NF-kappa B/metabolism , Raloxifene Hydrochloride/pharmacology , Tamoxifen/pharmacology , Active Transport, Cell Nucleus/drug effects , Animals , Atrial Natriuretic Factor/genetics , Body Weight , Female , Heart , Hemodynamics/drug effects , Myocardium/metabolism , Organ Size/drug effects , Ovariectomy , Rats , Selective Estrogen Receptor Modulators/pharmacology , Uterus/drug effects
4.
Fundam Clin Pharmacol ; 30(4): 316-26, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27148800

ABSTRACT

This study evaluated the effects of the isolated use of a low dose of methyltestosterone (MT) on cardiovascular reflexes and hormonal levels and its geno- and cytotoxic safety in ovariectomized rats. Female Wistar rats were divided into four groups (n = 6), respectively: SHAM (received vehicle methylcellulose 0.5%), SHAM + MT (received MT 0.05 mg/kg), OVX (received vehicle), and OVX + MT (received MT). Twenty-one days after ovariectomy, treatment was given orally daily for 28 days. The Bezold-Jarisch reflex (BJR) was analyzed by measuring the bradycardic and hypotensive responses elicited by phenylbiguanide (PBG) administration. The baroreflex sensitivity (BRS) was evaluated by phenylephrine and sodium nitroprussite. Myocyte hypertrophy was determined by morphometric analysis of H&E stained slides. Biochemical data were analyzed, as well as micronucleus assay. MT improved BRS and increased testosterone values, but did not change estradiol in the OVX group. MT did not promote changes in mean arterial pressure, heart rate, BJR, serum concentrations of troponin I, weight and histopathology of the heart. MT was able to restore the BRS in OVX rats. The geno- and cytotoxic safety of the MT was demonstrated by the absence of an increase in the micronucleus (PCEMN) or change in the ratio between normochromatic erythrocytes and polychromatic erythrocytes (NCE/PCE).


Subject(s)
Baroreflex/drug effects , Baroreflex/physiology , Methyltestosterone/administration & dosage , Ovariectomy , Animals , Cytotoxicity Tests, Immunologic/methods , Dose-Response Relationship, Drug , Female , Methyltestosterone/toxicity , Mutagenicity Tests/methods , Rats , Rats, Wistar
5.
J Diabetes Res ; 2014: 710370, 2014.
Article in English | MEDLINE | ID: mdl-25215305

ABSTRACT

AIM: To study the evolution of impaired fasting glucose (IFG), considering glucose and HbA1c levels and risk factors associated, in a period of 6 years. METHODS: We studied 94 subjects with impaired fasting glucose (IFG) that were diagnosed in 2005 and followed up to 2012. Glucose and HbA1c levels were determined. A descriptive analysis of contingence charts was performed in order to study the evolution in the development of type-2 diabetes mellitus (T2DM). RESULTS: Twenty-eight of ninety-four subjects became T2DM; 51/94 remained with IFG; and 20/94 presented normal fasting glucose. From the 28 diabetic subjects, 9 had already developed diabetes and were under treatment with oral hypoglycemic agents; 5 were diagnosed with plasma glucose < 126 mg/dL, but with HbA1c over 6.5%. In those who developed diabetes, 15/28 had a family history of T2DM in first relative degree. Also, diabetic subjects had a BMI significantly higher than nodiabetics (t test: P < 0.01). The individuals that in 2005 had the highest BMI are those who currently have diabetes. CONCLUSION: The IFG constitutes a condition of high risk of developing T2DM in a few years, especially over 110 mg/dL and in obesity patients.


Subject(s)
Blood Glucose/metabolism , Diabetes Mellitus, Type 2/blood , Fasting/blood , Glucose Metabolism Disorders/blood , Administration, Oral , Adult , Aged , Aged, 80 and over , Biomarkers/blood , Body Mass Index , Chile/epidemiology , Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/epidemiology , Diabetes Mellitus, Type 2/genetics , Disease Progression , Female , Follow-Up Studies , Genetic Predisposition to Disease , Glucose Metabolism Disorders/diagnosis , Glucose Metabolism Disorders/drug therapy , Glucose Metabolism Disorders/epidemiology , Glucose Metabolism Disorders/genetics , Glycated Hemoglobin/metabolism , Humans , Hypoglycemic Agents/administration & dosage , Male , Middle Aged , Obesity/diagnosis , Obesity/epidemiology , Pedigree , Risk Factors , Time Factors
6.
Rev. bras. farmacogn ; 24(4): 399-407, Jul-Aug/2014. graf
Article in English | LILACS | ID: lil-725638

ABSTRACT

Protium heptaphyllum (Aubl) Marchand, Burseraceae, is popularly used as an analgesic and anti-inflammatory agent. However, the cellular mechanism of action remains unknown. This study aims to evaluate the chemical composition of P. heptaphyllum resin and cytotoxicity on a breast cancer cell line (MCF-7). The chemical composition of the resin was determined by Gas Chromatography coupled to a Mass Spectrometer. The cytotoxicity was evaluated using an MTT assay. Annexin V-FITC, caspase-3, Angiotensin Converting Enzyme activity and Tumor Necrosis Factor alpha (TNF- α) assays were performed to evaluate apoptosis and inflammatory events. The resin consisted of triterpenes, such as α- and β-amyrin. Cytotoxicity was only observed in fractions enriched with α- and β-amyrin. The resin and fractions elicited antiproliferative activity, increased activity of caspase-3 and ACE, and a decrease in the TNF-α level. Altogether, the resin and fractions enriched with α- and β-amyrin promoted cytotoxicity and apoptosis.

7.
Hematol Oncol Stem Cell Ther ; 7(2): 69-75, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24486103

ABSTRACT

INTRODUCTION: Recent studies in image cytometry evaluated the replacement of specific markers by morphological parameters. The aim of this study was to develop and evaluate a method to identify subtypes of leukocytes using morphometric data of the nuclei. METHOD: The analyzed images were generated with a laser scanning cytometer. Two free programs were used for image analysis and statistical evaluation: Cellprofiler and Tanagra respectively. A sample of leukocytes with 200 sets of images (DAPI, CD45 and CD14) was analyzed. Using feature selection, the 20 best parameters were chosen to conduct cross-validation. RESULTS: The morphometric data identified the subpopulations of the analyzed leukocytes with a sensitivity and specificity of 0.95 per sample. CONCLUSION: The present study is the first that identifies subpopulations of leukocytes by nuclear morphology.


Subject(s)
Cell Nucleus/ultrastructure , Laser Scanning Cytometry/methods , Leukocytes/ultrastructure , Flow Cytometry , Humans , Sensitivity and Specificity
8.
Biol Trace Elem Res ; 158(1): 122-7, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24531910

ABSTRACT

Calcium, phytic acid, polyphenols and fiber are major inhibitors of iron absorption and they could be found in excess in some diets, thereby altering or modifying the iron nutrition status. The purpose of this study is to evaluate the effect of calcium, tannic acid, phytic acid, and pectin over iron uptake, using an in vitro model of epithelial cells (Caco-2 cell line). Caco-2 cells were incubated with iron (10-30 µM) with or without CaCl2 (500 and 1,000 µM) for 24 h. Then, cells were challenged with phytic acid (50-150 µM); pectin (50-150 nM) or tannic acid (100-500 µM) for another 24 h. Finally, (55)Fe (10 µM) uptake was determined. Iron dialyzability was studied using an in vitro digestion method. Iron uptake in cells pre-incubated with 20 and 30 µM Fe was inhibited by CaCl2 (500 µM). Iron uptake decreased in cells cultured with tannic acid (300 µM) and CaCl2 (500-1,000 µM) (two-way ANOVA, p = 0.002). Phytic acid also decreased iron uptake mainly when cells were treated with CaCl2 (1,000 µM) (two-way ANOVA; p < 0.05). Pectin slightly decreased iron uptake (p = NS). Iron dialyzability decreased when iron was mixed with CaCl2 and phytic or tannic acid (T test p < 0.0001, for both) but not when mixed with pectin. Phytic acid combined with calcium is a strong iron uptake inhibitor. Pectin slightly decreased iron uptake with or without calcium. Tannic acid showed an unexpected behavior, inducing an increase on iron uptake, despite its low Fe dialyzability.


Subject(s)
Calcium/pharmacology , Iron/pharmacokinetics , Pectins/pharmacology , Phytic Acid/pharmacology , Tannins/pharmacology , Adenocarcinoma/metabolism , Adenocarcinoma/pathology , Analysis of Variance , Caco-2 Cells , Calcium Chloride/pharmacology , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Dose-Response Relationship, Drug , Humans , Intestinal Absorption/drug effects , Iron/pharmacology , Models, Biological
9.
Eval Program Plann ; 42: 32-42, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24184843

ABSTRACT

We present the collaborative development of a web-based data collection and monitoring plan for thirty-two county councils within New Mexico's health council system. The monitoring plan, a key component in our multiyear participatory statewide evaluation process, was co-developed with the end users: representatives of the health councils. Guided by the Institute of Medicine's Community, Health Improvement Process framework, we first developed a logic model that delineated processes and intermediate systems-level outcomes in council development, planning, and community action. Through the online system, health councils reported data on intermediate outcomes, including policy changes and funds leveraged. The system captured data that were common across the health council system, yet was also flexible so that councils could report their unique accomplishments at the county level. A main benefit of the online system was that it provided the ability to assess intermediate, outcomes across the health council system. Developing the system was not without challenges, including creating processes to ensure participation across a large rural state; creating shared understanding of intermediate outcomes and indicators; and overcoming technological issues. Even through the challenges, however, the benefits of committing to using participatory processes far outweighed the challenges.


Subject(s)
Community Health Planning , Community-Based Participatory Research , Data Collection/methods , Health Care Coalitions/organization & administration , Health Planning Councils/organization & administration , Community Health Planning/organization & administration , Community-Based Participatory Research/organization & administration , Cooperative Behavior , Health Promotion/organization & administration , Humans , Internet , Models, Organizational , New Mexico , Program Development
10.
Biometals ; 25(4): 749-59, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22476617

ABSTRACT

Adipose tissue secretes numerous pro-inflammatory cytokines, such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α that can lead to insulin resistance (IR). In the liver, both IL-6 and TNF-α induce IR by inhibiting phosphorylation or ubiquitination of IRS1. In IR development, Fe is a risk factor in type-2 diabetes development. We studied the expression of genes related to inflammation, hypoxia, and mitochondrial function in hepatic (HepG2) and adipose (3T3-L1) cells. HepG2 and 3T3-L1 cells were incubated with 20 µM Fe, 40 µM Fe, or 40 µM Fe/20 mM glucose for 7 days and then challenged with 20 ng/ml IL-6 and/or 100 µM CoCl(2) for 20 h. We measured intracellular Fe levels and the relative expression of hepcidin, NF-κB, IL-6, TNF-α, hypoxia inducible factor 1α (HIF-1α), and mitofusin 2 (Mfn-2) mRNA using qRT-PCR. The intracellular Fe concentration in HepG2 cells did not change with 20 or 40 µM Fe. However, levels were decreased with Fe/glucose and IL-6 and/or CoCl(2). 3T3-L1 cells showed an increase in intracellular Fe with high Fe plus either IL-6 or CoCl(2). HepG2 cells incubated with 40 µM Fe alone or Fe/glucose and challenged with IL-6 and/or CoCl(2) showed increased IL-6, NF-κB, and TNF-α mRNA expression and decreased mRNA expression of Mfn-2 in all experimental conditions. 3T3-L1 cells incubated with 40 µM Fe alone or Fe/glucose and challenged with IL-6 showed increased NF-κB mRNA expression and decreased Mfn-2 expression in all experimental conditions. Thus, high Fe, inflammation, and hypoxia trigger the expression of genes related to inflammation and Fe metabolism in HepG2 cells, in 3T3-L1 cells the same stimuli increased NF-kB and hepcidin expression.


Subject(s)
Adipocytes/drug effects , Adipocytes/metabolism , Hepatocytes/drug effects , Hepatocytes/metabolism , Iron/pharmacology , 3T3-L1 Cells , Animals , Antimicrobial Cationic Peptides/metabolism , Cell Hypoxia/drug effects , Cell Hypoxia/genetics , Cobalt/pharmacology , GTP Phosphohydrolases/genetics , GTP Phosphohydrolases/metabolism , Hep G2 Cells , Hepcidins , Humans , Interleukin-6/pharmacology , Mice , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , NF-kappa B/genetics , Tumor Necrosis Factor-alpha/pharmacology
11.
Biol Trace Elem Res ; 149(1): 1-4, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22426798

ABSTRACT

This study aims to measure iron nutrition parameters and to determine the presence of anemia in obese type 2 diabetic patients and to analyze the mRNA relative abundance of genes related to inflammation, immune system, iron metabolism, and mitochondrial activity. Obese type 2 diabetic (OBDM, n=30) and healthy subjects (Cn, n=30) were studied. Biochemical, anthropometric, and iron nutrition parameters were determined. Peripheral mononuclear cells from type 2 diabetic and control group were challenged with high concentrations of iron (Fe) and glucose and total mRNA was isolated. The frequency of anemia among diabetic patients was 4/30. OBDM patients with or without anemia had higher levels of ferritin and high-sensitivity C-reactive protein than the Cn group. mRNA relative abundance of nuclear factor kappa-light-chain-enhancer of activated B cells was elevated in OBDM with anemia, and mRNA expression of interleukin-6 and toll-like receptor (TLR) 2 was increased in OBDM group in basal high Fe and high glucose concentrations. The expression of tumor necrosis factor alpha and TLR-4 was increased in OBDM with anemia in all experimental conditions. Hepcidin mRNA expression was increased in OBDM with anemia even in basal Fe concentration, and mitofusin 2 was decreased in all experimental conditions. This study shows that obese type 2 diabetic patients have iron distribution disorders associated to their proinflammatory state, and anemic subjects have a marked elevation of hepcidin mRNA expression.


Subject(s)
Anemia/blood , Antimicrobial Cationic Peptides/metabolism , Diabetes Mellitus, Type 2/blood , Ferritins/metabolism , Leukocytes, Mononuclear/metabolism , RNA, Messenger/metabolism , Adult , Anemia/complications , Anemia/genetics , Antimicrobial Cationic Peptides/genetics , Blood Glucose/metabolism , C-Reactive Protein/metabolism , Case-Control Studies , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/genetics , Ferritins/pharmacology , GTP Phosphohydrolases/genetics , GTP Phosphohydrolases/metabolism , Gene Expression Regulation , Glucose/metabolism , Glucose/pharmacology , Hepcidins , Humans , Inflammation/blood , Inflammation/genetics , Interleukin-6/genetics , Interleukin-6/metabolism , Leukocytes, Mononuclear/drug effects , Leukocytes, Mononuclear/pathology , Male , Middle Aged , Mitochondria/genetics , Mitochondria/metabolism , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , NF-kappa B/genetics , NF-kappa B/metabolism , Obesity/blood , Obesity/genetics , RNA, Messenger/genetics , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism , Tumor Necrosis Factor-alpha/metabolism , Waist Circumference
12.
Mar Pollut Bull ; 42(12): 1221-35, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11827108

ABSTRACT

The coast of Honduras, Central America, represents the southern end of the Mesoamerican Barrier Reef System, although its marine resources are less extensive and studied than nearby Belize and Mexico. However, the coastal zone contains mainland reef formations, mangroves, wetlands, seagrass beds and extensive fringing reefs around its offshore islands, and has a key role in the economy of the country. Like most tropical areas, this complex of benthic habitats experiences limited annual variation in climatic and oceanographic conditions but seasonal and occasional conditions, particularly coral bleaching and hurricanes, are important influences. The effects of stochastic factors on the country's coral reefs were clearly demonstrated during 1998 when Honduras experienced a major hurricane and bleaching event. Any natural or anthropogenic impacts on reef health will inevitably affect other countries in Latin America, and vice versa, since the marine resources are linked via currents and the functioning of the system transcends political boundaries. Much further work on, for example, movement of larvae and transfer of pollutants is required to delineate the full extent of these links. Anthropogenic impacts, largely driven by the increasing population and proportion of people living in coastal areas, are numerous and include key factors such as agricultural run-off, over-fishing, urban and industrial pollution (particularly sewage) and infrastructure development. Many of these threats act synergistically and, for example, poor watershed management via shifting cultivation, increases sedimentation and pesticide run-off onto coral reefs, which increases stress to corals already affected by decreasing water quality and coral bleaching. Threats from agriculture and fishing are particularly significant because of the size of both industries. The desire to generate urgently required revenue within Honduras has also led to increased tourism which provides an overarching stress to marine resources since most tourists spend time in the coastal zone. Hence the last decade has seen a dramatic increase in coastal development, a greater requirement for sewage treatment and more demand for freshwater, particularly in the Bay Islands. Although coastal zone management is relatively recent in Honduras, it is gaining momentum from both large-scale initiatives, such as the Ministry of Tourism's 'Bay Islands Environmental Management Project', and national and international NGO projects. For example, a series of marine protected areas and legislative regulations have been established, but management capacity, enforcement and monitoring are limited by funding, expertise and training. Existing and future initiatives, supported by increased political will and environmental awareness of stakeholders, are vital for the long-term economic development of the country.


Subject(s)
Conservation of Natural Resources , Water Pollution/adverse effects , Animals , Caribbean Region , Cnidaria , Disasters , Fisheries , Honduras , Humans , Population Growth , Seasons , Sewage/adverse effects , Sharks
13.
Biochim Biophys Acta ; 1426(3): 475-82, 1999 Feb 02.
Article in English | MEDLINE | ID: mdl-10076064

ABSTRACT

The search for effective iron chelating agents was primarily driven by the need to treat iron-loading refractory anemias such as beta-thalassemia major. However, there is a potential for therapeutic use of iron chelators in non-iron overload conditions. Iron can, under appropriate conditions, catalyze the production of toxic oxygen radicals which have been implicated in numerous pathologies and, hence, iron chelators may be useful as inhibitors of free radical-mediated tissue damage. We have developed the orally effective iron chelator pyridoxal isonicotinoyl hydrazone (PIH) and demonstrated that it inhibits iron-mediated oxyradical formation and their effects (e.g. 2-deoxyribose oxidative degradation, lipid peroxidation and plasmid DNA breaks). In this study we further characterized the mechanism of the antioxidant action of PIH and some of its analogs against *OH formation from the Fenton reaction. Using electron paramagnetic resonance (EPR) with 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap for *OH we showed that PIH and salicylaldehyde isonicotinoyl hydrazone (SIH) inhibited Fe(II)-dependent production of *OH from H2O2. Moreover, PIH protected 2-deoxyribose against oxidative degradation induced by Fe(II) and H2O2. The protective effect of PIH against both DMPO hydroxylation and 2-deoxyribose degradation was inversely proportional to Fe(II) concentration. However, PIH did not change the primary products of the Fenton reaction as indicated by EPR experiments on *OH-mediated ethanol radical formation. Furthermore, PIH dramatically enhanced the rate of Fe(II) oxidation to Fe(III) in the presence of oxygen, suggesting that PIH decreases the concentration of Fe(II) available for the Fenton reaction. These results suggest that PIH and SIH deserve further investigation as inhibitors of free-radical mediated tissue damage.


Subject(s)
Deoxyribose/chemistry , Hydroxyl Radical/chemistry , Isoniazid/analogs & derivatives , Pyridoxal/analogs & derivatives , Cyclic N-Oxides , Electron Spin Resonance Spectroscopy , Hydrogen Peroxide , Iron , Isoniazid/chemistry , Oxidation-Reduction , Pyridoxal/chemistry , Spin Trapping
15.
Dent Stud ; 61(8): 38-41, 43, 1983 May.
Article in English | MEDLINE | ID: mdl-6580237
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