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Leighton F, Poole B, Beaufay H, Baudhuin P, Coffey JW, Fowler S, De Duve C. The large-scale separation of peroxisomes, mitochondria, and lysosomes from the livers of rats injected with triton WR-1339. Improved isolation procedures, automated analysis, biochemical and morphological properties of fractions. J Biophys Biochem Cytol 1968; 37:482-513. [PMID: 4297786 PMCID: PMC2107417 DOI: 10.1083/jcb.37.2.482] [Citation(s) in RCA: 945] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Improved, largely automated methods are described for the purification and analysis o peroxisomes, lysosomes, and mitochondria from the livers of rats injected with Triton WR-1339. With these new methods, it has become possible to obtain, in less than 6 hr and with reliable reproducibility, mitochondria practically free of contaminants, as well as the rarer cytoplasmic particles in amounts (about 100 mg of protein) and in a state of purity (95%) that make them suitable for detailed biochemical studies. The results obtained so far on these preparations have made more conclusive and precise previous estimates of the biochemical and morphological properties of the three groups of cytoplasmic particles. In addition, peroxisomes were found to contain essentially all the L-alpha-hydroxy acid oxidase of the liver, as well as a small, but significant fraction of its NADP-linked isocitrate dehydrogenase activity. Another small fraction of the latter enzyme is present in the mitochondria, the remainder being associated with the cell sap. The mitochondrial localization of the metabolically active cytoplasmic DNA could be verified. The relative content of the fractions in mitochondria, whole peroxisomes, peroxisome cores, lysosomes, and endoplasmic reticulum was estimated independently by direct measurements on electron micrographs, and by linear programming (based on the assumption that the particles are biochemically homogeneous) of the results of enzyme assays. The two types of estimates agreed very well, except for one fraction in which low cytochrome oxidase activity was associated with mitochondrial damage.
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945 |
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Miranda S, Opazo C, Larrondo LF, Muñoz FJ, Ruiz F, Leighton F, Inestrosa NC. The role of oxidative stress in the toxicity induced by amyloid beta-peptide in Alzheimer's disease. Prog Neurobiol 2000; 62:633-48. [PMID: 10880853 DOI: 10.1016/s0301-0082(00)00015-0] [Citation(s) in RCA: 272] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
One of the theories involved in the etiology of Alzheimer's disease (AD) is the oxidative stress hypothesis. The amyloid beta-peptide (A beta), a hallmark in the pathogenesis of AD and the main component of senile plaques, generates free radicals in a metal-catalyzed reaction inducing neuronal cell death by a reactive oxygen species mediated process which damage neuronal membrane lipids, proteins and nucleic acids. Therefore, the interest in the protective role of different antioxidants in AD such as vitamin E, melatonin and estrogens is growing up. In this review we summarize data that support the involvement of oxidative stress as an active factor in A beta-mediated neuropathology, by triggering or facilitating neurodegeneration, through a wide range of molecular events that disturb neuronal cell homeostasis.
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Review |
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272 |
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Bronfman M, Inestrosa NC, Leighton F. Fatty acid oxidation by human liver peroxisomes. Biochem Biophys Res Commun 1979; 88:1030-6. [PMID: 465070 DOI: 10.1016/0006-291x(79)91512-2] [Citation(s) in RCA: 182] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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46 |
182 |
4
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Inestrosa NC, Bronfman M, Leighton F. Detection of peroxisomal fatty acyl-coenzyme A oxidase activity. Biochem J 1979; 182:779-88. [PMID: 518563 PMCID: PMC1161412 DOI: 10.1042/bj1820779] [Citation(s) in RCA: 163] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It has been postulated that the peroxisomal fatty acid-oxidizing system [Lazarow & de Duve (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 2043--2046; Lazarow (1978) J. Biol. Chem. 253, 1522--1528] resembles that of mitochondria, except for the first oxidative reaction. In this step, O2 would be directly reduced to H2O2 by an oxidase. Two specific procedures developed to detect the activity of the characteristic enzyme fatty acyl-CoA oxidase are presented, namely polarographic detection of palmitoyl-CoA-dependent cyanide-insensitive O2 consumption and palmitoyl-CoA-dependent H2O2 generation coupled to the peroxidation of methanol in an antimycin A-insensitive reaction. Fatty acyl-CoA oxidase activity is stimulated by FAD, which supports the flavoprotein nature postulated for this enzyme. Its activity increases 7-fold per g wet wt. of liver in rats treated with nafenopin, a hypolipidaemic drug. Subcellular fractionation of livers from normal and nafenopin-treated animals provides evidence for its peroxisomal localization. The stoicheiometry for palmitoyl-CoA-dependent O2 consumption, H2O2 generation and NAD+ reduction is 1 : 1 : 1. This suggests that fatty acyl-CoA oxidase is the rate-limiting enzyme of the peroxisomal fatty acid-oxidizing system.
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Abstract
In recent years there has been a remarkable increment in scientific articles dealing with oxidative stress. Several reasons justify this trend: knowledge about reactive oxygen and nitrogen species metabolism; definition of markers for oxidative damage; evidence linking chronic diseases and oxidative stress; identification of flavonoids and other dietary polyphenol antioxidants present in plant foods as bioactive molecules; and data supporting the idea that health benefits associated with fruits, vegetables and red wine in the diet are probably linked to the polyphenol antioxidants they contain. In this review we examine some of the evidence linking chronic diseases and oxidative stress, the distribution and basic structure of plant polyphenol antioxidants, some biological effects of polyphenols, and data related to their bioavailability and the metabolic changes they undergo in the intestinal lumen and after absorption into the organism. Finally, we consider some of the challenges that research in this area currently faces, with particular emphasis on the contributions made at the International Symposium "Biology and Pathology of Free Radicals: Plant and Wine Polyphenol Antioxidants" held July 29-30, 1999, at the Catholic University, Santiago, Chile and collected in this special issue of Biological Research.
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Review |
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Leighton F, Coloma L, Koenig C. Structure, composition, physical properties, and turnover of proliferated peroxisomes. A study of the trophic effects of Su-13437 on rat liver. J Cell Biol 1975; 67:281-309. [PMID: 406 PMCID: PMC2109608 DOI: 10.1083/jcb.67.2.281] [Citation(s) in RCA: 143] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Peroxisome proliferation has been induced with 2-methyl-2-(p-[1,2,3,4-tetrahydro-1-naphthyl]-phenoxy)-propionic acid (Su-13437). DNA, protein, cytochrome oxidase, glucose-6-phosphatase, and acid phosphatase concentrations remain almost constant. Peroxisomal enzyme activities change to approximately 165%, 50%, 30%, and 0% of the controls for catalase, urate oxidase, L-alpha-hydroxy acid oxidase, and D-amino acid oxidase, respectively. For catalase the change results from a decrease in particle-bound activity and a fivefold increase in soluble activity. The average diameter of peroxisome sections is 0.58 +/- 0.15 mum in controls and 0.73 +/- 0.25 mum after treatment. Therefore, the measured peroxisomal enzymes are highly diluted in proliferated particles. After tissue fractionation, approximately one-half of the normal peroxisomes and all proliferated peroxisomes show matric extraction with ghost formation, but no change in size. In homogenates submitted to mechanical stress, proliferated peroxisomes do not reveal increased fragility; unexpectedly, Su-13437 stabilizes lysosomes. Our results suggest that matrix extraction and increased soluble enzyme activities result from transmembrane passage of peroxisomal proteins. The changes in concentration of peroxisomal oxidases and soluble catalase after Su-13437 allow the calculation of their half-lives. These are the same as those found for total catalase, in normal and treated rats, after allyl isopropyl acetamide: about 1.3 days, a result compatible with peroxisome degradation by autophagy. A sequential increase in liver RNA concentration, [14C]leucine incorporation into DOC-soluble proteins and into immunoprecipitable catalase, and an increase in liver size and peroxisomal volume per gram liver, characterize the trophic effect of the drug used. In males, Su-13437 is more active than CPIB, another peroxisome proliferation-inducing drug; in females, only Su-13437 is active.
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50 |
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Miranda S, Foncea R, Guerrero J, Leighton F. Oxidative stress and upregulation of mitochondrial biogenesis genes in mitochondrial DNA-depleted HeLa cells. Biochem Biophys Res Commun 1999; 258:44-9. [PMID: 10222232 DOI: 10.1006/bbrc.1999.0580] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The signaling mechanism through which deficitary mitochondrial function would activate nuclear genes required for mitochondrial biogenesis, has not been established. To explore the hypothesis that reactive oxygen species (ROS), a mitochondrial product, constitute part of the mitochondria-nuclei signaling pathway, we obtained HeLa cells depleted of mitochondrial DNA (rho0 cells) through exposure to ethidium bromide. We found evidences of oxidative stress in rho0 cells, employing a fluorescent probe and measuring NF-kappaB activation. Nuclear Respiratory Factor-1 (NRF-1) and Mitochondrial Transcription Factor A (Tfam) mRNA were measured by RT-PCR. For both transcription factors, rho0 cells revealed significantly higher levels of mRNA. These results support several hypothesis: that endogenous ROS enhance the expression of nuclear mitochondrial biogenesis genes NRF-1 and Tfam; that DNA deprived mitochondria lead to cellular oxidative stress, probably because of incomplete biogenesis of the mitochondrial electron transport chain, and consequently, that ROS are part of a mitochondria-nuclei regulatory signaling pathway.
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Leighton F, Poole B, Lazarow PB, De Duve C. The synthesis and turnover of rat liver peroxisomes. I. Fractionation of peroxisome proteins. J Biophys Biochem Cytol 1969; 41:521-35. [PMID: 4389026 PMCID: PMC2107759 DOI: 10.1083/jcb.41.2.521] [Citation(s) in RCA: 123] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Rat liver peroxisomes isolated by density gradient centrifugation were disrupted at pH 9, and subdivided into a soluble fraction containing 90% of their total proteins and virtually all of their catalase, D-amino acid oxidase, L-alpha-hydroxy acid oxidase and isocitrate dehydrogenase activities, and a core fraction containing urate oxidase and 10% of the total proteins. The soluble proteins were chromatographed on Sephadex G-200, diethylaminoethyl (DEAE)-cellulose, hydroxylapatite, and sulfoethyl (SE)-Sephadex. None of these methods provided complete separation of the protein components, but these could be distributed into peaks in which the specific activities of different enzymes were substantially increased. Catalase, D-amino acid oxidase, and L-alpha-hydroxy acid oxidase contribute a maximum of 16, 2, and 4%, respectively, of the protein of the peroxisome. The contribution of isocitrate dehydrogenase could be as much as 25%, but is probably much less. After dissolution of the cores at pH 11 , no separation between their urate oxidase activity and their protein was achieved by Sephadex G-200 chromatography.
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Poole B, Leighton F, De Duve C. The synthesis and turnover of rat liver peroxisomes. II. Turnover of peroxisome proteins. J Cell Biol 1969; 41:536-46. [PMID: 5783872 PMCID: PMC2107746 DOI: 10.1083/jcb.41.2.536] [Citation(s) in RCA: 117] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
After preliminary experiments had established that the injection of Triton WR-1339 necessary for the separation of lysosomes and peroxisomes did not affect the turnover rate of catalase, the decay of (3)H-leucine incorporated into peroxisomes was studied in whole particles and in protein subfractions. It was shown that peroxisomes are destroyed in a completely random way, probably as wholes since the apparent half-life was the same for all subfractions, about 3(1/2) days. In agreement with the results of Price et al. (11), the half-life of catalase derived from the rate of recovery from aminotriazole inhibition was about 11(1/2) days, as was the apparent half-life of the heme prosthetic groups measured with (14)C-alpha-aminolevulinic acid. Guanidino-labeled arginine gave an apparent half-life of 2(1/2) days with large statistical uncertainty. Either the leucine label was reutilized very extensively in our animals and the true half-life of peroxisomes is 1(1/2) days, or the prosthetic groups of catalase turn over more rapidly than the protein part of the molecule.
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Cuevas AM, Guasch V, Castillo O, Irribarra V, Mizon C, San Martin A, Strobel P, Perez D, Germain AM, Leighton F. A high-fat diet induces and red wine counteracts endothelial dysfunction in human volunteers. Lipids 2000; 35:143-8. [PMID: 10757544 DOI: 10.1007/bf02664763] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Endothelial dysfunction is associated with atherogenesis and oxidative stress in humans. In rat and rabbit blood vessels, wine polyphenol antioxidants induce vascular relaxation in vitro through the NO-cGMP pathway. To assess the effect of a regular high-fat diet (HFD) and moderate red wine consumption on endothelial function (EF), a study was performed in healthy male volunteers. EF was measured as flow-mediated dilatation of the brachial artery, employing high-resolution ultrasound after an overnight fast. Other clinical and biochemical parameters related to EF were also measured. Six volunteers received a control diet, rich in fruits and vegetables (27% calories as fat) and five volunteers received an HFD (39.5% calories as fat). Measurements were done twice on each volunteer: after a period of 30 d with diet plus 240 mL of red wine/d, and after a period of 30 d with diet, without wine. In the absence of wine, there is a reduction of EF with HFD when compared to the control diet (P = 0.014). This loss of EF is not seen when both diets are supplemented with wine for 30 d (P = 0.001). Plasma levels of n-3 fatty acids (R2 = 0.232, P = 0.023) and lycopene (R2 = 0.223, P = 0.020) show a positive correlation with individual EF measurements, but they do not account for the significant differences observed among dietary groups or after wine supplementation. These results help elucidate the deleterious effect of a high-fat diet and the protective role of wine, n-3 fatty acids and dietary antioxidants in cardiovascular disease.
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108 |
11
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Leighton F, Bergseth S, Rørtveit T, Christiansen EN, Bremer J. Free Acetate Production by Rat Hepatocytes during Peroxisomal Fatty Acid and Dicarboxylic Acid Oxidation. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)81625-8] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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103 |
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Leighton T, Marks E, Leighton F. Pesticides: Insecticides and Fungicides Are Chitin Synthesis Inhibitors. Science 1981; 213:905-7. [PMID: 17775276 DOI: 10.1126/science.213.4510.905] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Several important groups of fungicides and insecticides are specific inhibitors of chitin synthesis in a Phycomyces enzyme system and in insect organ cultures. The recently discovered benzoylphenylurea insecticides, which prevent chitin synthesis in insect tissues, are apparently not direct-acting chitin synthetase inhibitors. These insecticides may prevent insect chitin synthesis by interfering with the proteolytic activation of the chitin synthetase zymogen.
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79 |
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Mezzano D, Pais EO, Aranda E, Panes O, Downey P, Ortiz M, Tagle R, González F, Quiroga T, Caceres MS, Leighton F, Pereira J. Inflammation, not hyperhomocysteinemia, is related to oxidative stress and hemostatic and endothelial dysfunction in uremia. Kidney Int 2001; 60:1844-1850. [PMID: 11703602 DOI: 10.1046/j.1523-1755.2001.00998.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2025]
Abstract
BACKGROUND Several cardiovascular risk factors are present in patients with chronic renal failure (CRF), among which are systemic inflammation and hyperhomocysteinemia. Increased oxidative stress, endothelial activation/dysfunction, and coagulation activation are considered integral components of the inflammatory response, but have also been proposed as mediators of plasma homocysteine (tHcy)-induced cell damage. Using correlation analysis, we assessed the relative contributions of inflammation and hyperhomocysteinemia in the abnormal oxidative stress, endothelial activation/dysfunction, and hemostasis activation in patients with CRF. METHODS The relationships of inflammatory proteins and tHcy with plasma markers of these processes were studied in 64 patients with CRF (serum creatinine 526 +/- 319 micromol/L) on conservative treatment, comparing the results with healthy controls (N = 15 to 40, depending on the measured variable) of similar sex and age. RESULTS Patients had significant increases in inflammatory cytokines (TNF-alpha and IL-8) and acute-phase proteins (C-reactive protein, fibrinogen and alpha1-antitrypsin). tHcy was increased in 87.5% of patients (mean = 27.1 micromol/L, range 6.5 to 118). Patients had significant increases in (1) indices of oxidative stress: TBARS (thiobarbituric acid-reactive species), a marker of lipid peroxidation and AOPP (advanced oxidation protein products), a marker of protein oxidation; (2) endothelial cell markers such as von Willebrand factor (vWF:Ag), soluble ICAM-1 and soluble thrombomodulin (sTM); (3) markers of intravascular thrombin generation: thrombin-antithrombin complexes (TAT) and prothrombin fragment F(1+2) (PF(1+2)); and (4) indices of activation of fibrinolysis: plasmin-antiplasmin complexes (PAP), fibrin degradation products (FnDP) and fibrinogen degradation products (FgDP). tHcy was significantly correlated with plasma creatinine (r = 0.29, P < 0.018) and with serum folate (r = -0.38, P < 0.002). However, no significant correlations were observed between tHcy and TBARS, AOPP, vWF:Ag, sICAM-1, sTM, TAT, F(1+2), sTF, PAP, FnDP, and FgDP. Conversely, acute-phase proteins showed significant, positive correlations with most markers of oxidative stress, endothelial dysfunction and hemostatic activation. CONCLUSIONS Systemic inflammation, which is closely associated with augmented oxidative stress, endothelial cell dysfunction and hemostatic activation, emerges as a major cardiovascular risk factor in CRF. tHcy is unrelated to these events. Thus, alternative mechanisms through which hyperhomocysteinemia could predispose to vascular lesion and thrombotic events in CRF needs to be investigated.
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71 |
14
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Abstract
Endothelial dysfunction (ED) is an early event in atherosclerotic disease, preceding clinical manifestations and complications. Increased reactive oxygen species (ROS) have been implicated as important mechanisms that contribute to ED, and ROS's may function as intracellular messengers that modulate signaling pathways. Several intracellular signal events stimulated by ROS have been defined, including the identification of two members of the mitogen activated protein kinase family (ERK1/2 and big MAP kinase, BMK1), tyrosine kinases (Src and Syk) and different isoenzymes of PKC as redox-sensitive kinases. ROS regulation of signal transduction components include the modification in the activity of transcriptional factors such as NFkB and others that result in changes in gene expression and modifications in cellular responses. In order to understand the intracellular mechanisms induced by ROS in endothelial cells (EC), we are studying the response of human umbilical cord vein endothelial cells to increased ROS generation by different pro-atherogenic stimuli. Our results show that Homocysteine (Hcy) and oxidized LDL (oxLDL) enhance the activity and expression of oxidative stress markers, such as NFkB and heme oxygenase 1. These results suggest that these pro-atherogenic stimuli increase oxidative stress in EC, and thus explain the loss of endothelial function associated with the atherogenic process.
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Research Support, Non-U.S. Gov't |
20 |
61 |
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Mezzano D, Leighton F, Martínez C, Marshall G, Cuevas A, Castillo O, Panes O, Muñoz B, Pérez DD, Mizón C, Rozowski J, San Martín A, Pereira J. Complementary effects of Mediterranean diet and moderate red wine intake on haemostatic cardiovascular risk factors. Eur J Clin Nutr 2001; 55:444-51. [PMID: 11423921 DOI: 10.1038/sj.ejcn.1601202] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2000] [Revised: 01/22/2001] [Accepted: 01/24/2001] [Indexed: 11/09/2022]
Abstract
OBJECTIVES To compare the effect of alcohol-free Mediterranean-type diet (MD) and high-fat diet (HFD) on plasma concentration of emergent haemostatic cardiovascular risk factors (HCVRF). Also, to test if red wine supplementation modifies HCVRF, independent of diet. DESIGN, SUBJECTS AND INTERVENTION Controlled prospective intervention study. Two groups, each of 21 healthy male university students (22+/-3.4 y), received either MD or HFD for 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline and T30, T60 and T90-day samples were drawn. No drop out from the study was observed. SETTING University campus and outpatient nutrition clinic. RESULTS Volunteers on HFD at T30 had increases in pro-coagulants fibrinogen (22%), factor VIIc (9%), and factor VIIIc (4%), and decreases in natural anticoagulants antithrombin III (3%), protein C (11%) and protein S (6%) and of 20% in plasminogen activator inhibitor-1. At the same time, individuals on MD had increases in fibrinogen (4%), antithrombin III (5%), protein C (3%), protein S (2.7%), and decreases in factor VIIIc (9%), and plasminogen activator inhibitor-1 (21%). After adjusting by baseline values, MD was associated with lower plasma fibrinogen (P=0.03), factor VIIc (P=0.034) and factor VIIIc (P=0.0057) and with higher levels of protein S (P=0.013). Red wine supplementation, in both diets, resulted in decreased plasma fibrinogen (P=0.001) and factor VIIc (P=0.05), and increased tissue plasminogen activator antigen (P=0.01) and plasminogen activator inhibitor-1 antigen (P=0.0003). Wine consumption was also associated with significantly (P=0.01) divergent effects on antithrombin III: it decreased by 10% in individuals on HFD but increased slightly in those on MD. No effects of diet or wine were detected in plasma protein C and C-reactive protein. CONCLUSION MD and moderate consumption of red wine have complementary, mostly beneficial effects on HCVRF.
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Clinical Trial |
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Bronfman M, Inestrosa NC, Nervi FO, Leighton F. Acyl-CoA synthetase and the peroxisomal enzymes of beta-oxidation in human liver. Quantitative analysis of their subcellular localization. Biochem J 1984; 224:709-20. [PMID: 6240978 PMCID: PMC1144505 DOI: 10.1042/bj2240709] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The presence of acyl-CoA synthetase (EC 6.2.1.3) in peroxisomes and the subcellular distribution of beta-oxidation enzymes in human liver were investigated by using a single-step fractionation method of whole liver homogenates in metrizamide continuous density gradients and a novel procedure of computer analysis of results. Peroxisomes were found to contain 16% of the liver palmitoyl-CoA synthetase activity, and 21% and 60% of the enzyme activity was localized in mitochondria and microsomal fractions respectively. Fatty acyl-CoA oxidase was localized exclusively in peroxisomes, confirming previous results. Human liver peroxisomes were found to contribute 13%, 17% and 11% of the liver activities of crotonase, beta-hydroxyacyl-CoA dehydrogenase and thiolase respectively. The absolute activities found in peroxisomes for the enzymes investigated suggest that in human liver fatty acyl-CoA oxidase is the rate-limiting enzyme of the peroxisomal beta-oxidation pathway, when palmitic acid is the substrate.
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41 |
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Feytmans E, Leighton F. Effects of pyrazole and 3-amino-1,2,4-triazole on methanol and ethanol metabolism by the rat. Biochem Pharmacol 1973; 22:349-60. [PMID: 4687132 DOI: 10.1016/0006-2952(73)90416-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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50 |
18
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Labarca P, Wolff D, Soto U, Necochea C, Leighton F. Large cation-selective pores from rat liver peroxisomal membranes incorporated to planar lipid bilayers. J Membr Biol 1986; 94:285-91. [PMID: 2435912 DOI: 10.1007/bf01869724] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fusion of a highly purified fraction of rat liver peroxisomal membranes to planar lipid bilayers incorporates large, cation-selective voltage-dependent pores. The PK/PCl ratio of these pores, estimated in KCl gradients, is close to 4. The pores display several conductance states and spend most of the time open at voltages near 0 mV, closing at more positive and negative voltages. At voltages near 0 mV the most frequent open state has a conductance of 2.4 nS in 0.3 M KCl. At voltages more positive and more negative than 10 mV the most frequent open state displays a conductance of 1.2 nS in 0.3 M KCl. With these results pore diameters of 3 and 1.5 nm, respectively, can be estimated. We suggest that these pores might account for the unusually high permeability of peroxisomes to low molecular weight solutes. Fusion also incorporates a perfectly anion-selective, two-open states channel with conductances of 50 and 100 pS in 0.1 M KCl.
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Inestrosa NC, Bronfman M, Leighton F. Purification of the peroxisomal fatty acyl-CoA oxidase from rat liver. Biochem Biophys Res Commun 1980; 95:7-12. [PMID: 7417271 DOI: 10.1016/0006-291x(80)90696-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Skorin C, Necochea C, Johow V, Soto U, Grau AM, Bremer J, Leighton F. Peroxisomal fatty acid oxidation and inhibitors of the mitochondrial carnitine palmitoyltransferase I in isolated rat hepatocytes. Biochem J 1992; 281 ( Pt 2):561-7. [PMID: 1736904 PMCID: PMC1130722 DOI: 10.1042/bj2810561] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Fatty acid oxidation was studied in the presence of inhibitors of carnitine palmitoyltransferase I (CPT I), in normal and in peroxisome-proliferated rat hepatocytes. The oxidation decreased in mitochondria, as expected, but in peroxisomes it increased. These two effects were seen, in variable proportions, with (+)-decanoylcarnitine, 2-tetradecylglycidic acid (TDGA) and etomoxir. The decrease in mitochondrial oxidation (ketogenesis) affected saturated fatty acids with 12 or more carbon atoms, whereas the increase in peroxisomal oxidation (H2O2 production) affected saturated fatty acids with 8 or more carbon atoms. The peroxisomal increase was sensitive to chlorpromazine, a peroxisomal inhibitor. To study possible mechanisms, palmitoyl-, octanoyl- and acetyl-carnitine acyltransferase activities were measured, in homogenates and in subcellular fractions from control and TDGA-treated cells. The palmitoylcarnitine acyltransferase was inhibited, as expected, but the octanoyltransferase activity also decreased. The CoA derivative of TDGA was synthesized and tentatively identified as being responsible for inhibition of the octanoylcarnitine acyltransferase. These results show that inhibitors of the mitochondrial CPT I may also inhibit the peroxisomal octanoyl transferase; they also support the hypothesis that the octanoyltransferase has the capacity to control or regulate peroxisomal fatty acid oxidation.
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Santos MJ, Ojeda JM, Garrido J, Leighton F. Peroxisomal organization in normal and cerebrohepatorenal (Zellweger) syndrome fibroblasts. Proc Natl Acad Sci U S A 1985; 82:6556-60. [PMID: 2995971 PMCID: PMC391248 DOI: 10.1073/pnas.82.19.6556] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The reported absence of morphologically detectable peroxisomes in liver and kidney tissue cells from patients affected by the autosomic recessive, inherited metabolic disease known as cerebrohepatorenal, or Zellweger, syndrome was studied in fibroblasts, assuming it to be a generalized defect. Normal cultured fibroblasts were shown to contain peroxisomes according to morphological, biochemical, and subcellular fractionation criteria: particle-bound catalase and fatty acyl-CoA oxidase copurify in subcellular fractionation by differential centrifugation or isopycnic equilibrium in continuous density gradients and peroxidase-positive organelles of approximately equal to 0.1 micron in diameter are detected in the cytoplasm. In Zellweger cultured fibroblasts, these peroxisomal enzymes are present; however, they behave as cytosolic enzymes in the different subcellular fractionation procedures employed and peroxisomes are not detected cytochemically. These findings support the hypothesis that the lack of peroxisomes in this genetic disease is the consequence of a defect in the assembly of the peroxisomal constituents. Furthermore, the value of fibroblasts for subcellular analysis of peroxisomal defects is illustrated.
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Perez DD, Leighton F, Aspee A, Aliaga C, Lissi E. A comparison of methods employed to evaluate antioxidant capabilities. Biol Res 2000; 33:71-7. [PMID: 15693273 DOI: 10.4067/s0716-97602000000200006] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Three different methodologies frequently employed to evaluate the indexes that report the antioxidant capabilities of pure compounds and/or complex mixtures of antioxidants are applied to a series of mono- and polyphenols, as well as to two wine (red and white) samples. These methodologies are based on the bleaching of a stable radical, the effect of the additive upon luminol chemiluminescence induced by peroxyl radicals, and the effect of the additive upon the bleaching of the fluorescence from a dye molecule. Widely different responses are obtained from the different methodologies. These differences are interpreted in terms of the different factors (stoichiometric factors and/or reactivities) that determines the indexes evaluated by these different methodologies.
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Leighton F, Pérsico R, Necochea C. Peroxisomal fatty acid oxidation is selectively inhibited by phenothiazines in isolated hepatocytes. Biochem Biophys Res Commun 1984; 120:505-11. [PMID: 6732769 DOI: 10.1016/0006-291x(84)91283-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The production of hydrogen peroxide by isolated hepatocytes in response to lauric, palmitic and oleic acids, a measurement of peroxisomal fatty acid oxidation, is inhibited by phenothiazines under conditions in which ketone body production, a measurement of mitochondrial fatty acid oxidation, does not reveal inhibition of mitochondrial activity. This novel finding provides a pharmacological tool for the study of peroxisomal function in whole cells. The mechanism of this effect of phenothiazines, detected in hepatocytes from rats treated with a peroxisome proliferation inducing drug, is not yet known.
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Mezzano D, Pais EO, Aranda E, Panes O, Downey P, Ortiz M, Tagle R, González F, Quiroga T, Caceres MS, Leighton F, Pereira J. Inflammation, not hyperhomocysteinemia, is related to oxidative stress and hemostatic and endothelial dysfunction in uremia. Kidney Int 2001; 60:1844-50. [PMID: 11703602 DOI: 10.1046/j.1523-1755.2001.00996.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Several cardiovascular risk factors are present in patients with chronic renal failure (CRF), among which are systemic inflammation and hyperhomocysteinemia. Increased oxidative stress, endothelial activation/dysfunction, and coagulation activation are considered integral components of the inflammatory response, but have also been proposed as mediators of plasma homocysteine (tHcy)-induced cell damage. Using correlation analysis, we assessed the relative contributions of inflammation and hyperhomocysteinemia in the abnormal oxidative stress, endothelial activation/dysfunction, and hemostasis activation in patients with CRF. METHODS The relationships of inflammatory proteins and tHcy with plasma markers of these processes were studied in 64 patients with CRF (serum creatinine 526 +/- 319 micromol/L) on conservative treatment, comparing the results with healthy controls (N = 15 to 40, depending on the measured variable) of similar sex and age. RESULTS Patients had significant increases in inflammatory cytokines (TNF-alpha and IL-8) and acute-phase proteins (C-reactive protein, fibrinogen and alpha1-antitrypsin). tHcy was increased in 87.5% of patients (mean = 27.1 micromol/L, range 6.5 to 118). Patients had significant increases in (1) indices of oxidative stress: TBARS (thiobarbituric acid-reactive species), a marker of lipid peroxidation and AOPP (advanced oxidation protein products), a marker of protein oxidation; (2) endothelial cell markers such as von Willebrand factor (vWF:Ag), soluble ICAM-1 and soluble thrombomodulin (sTM); (3) markers of intravascular thrombin generation: thrombin-antithrombin complexes (TAT) and prothrombin fragment F(1+2) (PF(1+2)); and (4) indices of activation of fibrinolysis: plasmin-antiplasmin complexes (PAP), fibrin degradation products (FnDP) and fibrinogen degradation products (FgDP). tHcy was significantly correlated with plasma creatinine (r = 0.29, P < 0.018) and with serum folate (r = -0.38, P < 0.002). However, no significant correlations were observed between tHcy and TBARS, AOPP, vWF:Ag, sICAM-1, sTM, TAT, F(1+2), sTF, PAP, FnDP, and FgDP. Conversely, acute-phase proteins showed significant, positive correlations with most markers of oxidative stress, endothelial dysfunction and hemostatic activation. CONCLUSIONS Systemic inflammation, which is closely associated with augmented oxidative stress, endothelial cell dysfunction and hemostatic activation, emerges as a major cardiovascular risk factor in CRF. tHcy is unrelated to these events. Thus, alternative mechanisms through which hyperhomocysteinemia could predispose to vascular lesion and thrombotic events in CRF needs to be investigated.
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Olson SH, Parmley J, Soos C, Gilbert M, Latorre-Margalef N, Hall JS, Hansbro PM, Leighton F, Munster V, Joly D. Sampling strategies and biodiversity of influenza A subtypes in wild birds. PLoS One 2014; 9:e90826. [PMID: 24599502 PMCID: PMC3944928 DOI: 10.1371/journal.pone.0090826] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 02/04/2014] [Indexed: 02/07/2023] Open
Abstract
Wild aquatic birds are recognized as the natural reservoir of avian influenza A viruses (AIV), but across high and low pathogenic AIV strains, scientists have yet to rigorously identify most competent hosts for the various subtypes. We examined 11,870 GenBank records to provide a baseline inventory and insight into patterns of global AIV subtype diversity and richness. Further, we conducted an extensive literature review and communicated directly with scientists to accumulate data from 50 non-overlapping studies and over 250,000 birds to assess the status of historic sampling effort. We then built virus subtype sample-based accumulation curves to better estimate sample size targets that capture a specific percentage of virus subtype richness at seven sampling locations. Our study identifies a sampling methodology that will detect an estimated 75% of circulating virus subtypes from a targeted bird population and outlines future surveillance and research priorities that are needed to explore the influence of host and virus biodiversity on emergence and transmission.
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