863 resultados para GLUTATHIONE-PEROXIDASE
Resumo:
The upstream proinflammatory interleukin-1 (IL-1) cytokines, together with a naturally occurring IL-1 receptor antagonist (IL-1Ra), play a significant role in several diseases and physiologic conditions. The IL-1 proteins affect glucose homeostasis at multiple levels contributing to vascular injuries and metabolic dysregulations that precede diabetes. An association between IL-1 gene variations and IL-1Ra levels has been suggested, and genetic studies have reported associations with metabolic dysregulation and altered inflammatory responses. The principal aims of this study were to: 1) examine the associations of IL-1 gene variation and IL-1Ra expression in the development and persistence of thyroid antibodies in subacute thyroiditis; 2) investigate the associations of common variants in the IL-1 gene family with plasma glucose and insulin concentrations, glucose homeostasis measures and prevalent diabetes in a representative population sample; 3) investigate genetic and non-genetic determinants of IL-1Ra phenotypes in a cross-sectional setting in three independent study populations; 4) investigate in a prospective setting (a) whether variants of the IL-1 gene family are predictors for clinically incident diabetes in two population-based observational cohort studies; and (b) whether the IL-1Ra levels predict the progression of metabolic syndrome to overt diabetes during the median follow-up of 10.8 and 7.1 years. Results from on patients with subacte thyroiditis showed that the systemic IL-1Ra levels are elevated during a specific proinflammatory response and they correlated with C-reactive protein (CRP) levels. Genetic variation in the IL-1 family seemed to have an association with the appearance of thyroid peroxidase antibodies and persisting local autoimmune responses during the follow-up. Analysis of patients suffering from diabetes and metabolic traits suggested that genetic IL-1 variation and IL-1Ra play a role in glucose homeostasis and in the development of type 2 diabetes. The coding IL-1 beta SNP rs1143634 was associated with traits related to insulin resistance in cross-sectional analyses. Two haplotype variants of the IL-1 beta gene were associated with prevalent diabetes or incident diabetes in a prospective setting and both of these haplotypes were tagged by rs1143634. Three variants of the IL-1Ra gene and one of the IL-1 beta gene were consistently identified as significant, independent determinants of the IL-1Ra phenotype in two or three populations. The proportion of the phenotypic variation explained by the genetic factors was modest however, while obesity and other metabolic traits explained a larger part. Body mass index was the strongest predictor of systemic IL-1Ra concentration overall. Furthermore, the age-adjusted IL-1Ra concentrations were elevated in individuals with metabolic syndrome or diabetes when compared to those free of metabolic dysregulation. In prospective analyses the systemic IL-1Ra levels were found as independent predictors for the development of diabetes in people with metabolic syndrome even after adjustment for multiple other factors, including plasma glucose and CRP levels. The predictive power of IL-1Ra was better than that of CRP. The prospective results also provided some evidence for a role of common IL-1 alpha promoter SNP rs1800587 in the development of type 2 diabetes among men and suggested that the role may be gender specific. Likewise, common variations in the IL-1 beta coding region may have a gender specific association with diabetes development. Further research on the potential benefits of IL-1Ra measurements in identifying individuals at high risk for diabetes, who then could be targeted for specific treatment interventions, is warranted. It has been reported in the recent literature that IL-1Ra secreted from adipose tissue has beneficial effects on glucose homeostasis. Furthermore, treatment with recombinant human IL-1Ra has been shown to have a substantial therapeutic potential. The genetic results from the prospective analyses performed in this study remain inconclusive, but together with the cross-sectional analyses they suggest gender-specific effects of the IL-1 variants on the risk of diabetes. Larger studies with more extensive genotyping and resequencing may help to pinpoint the exact variants responsible and to further elucidate the biological mechanisms for the observed associations. This would improve our understanding of the pathways linking inflammation and obesity with glucose and insulin metabolism.
Resumo:
Lung cancer accounts for more cancer-related deaths than any other cancer. In Finland, five-year survival ranges from 8% to 13%. The main risk factor for lung cancer is long-term cigarette smoking, but its carcinogenesis requires several other factors. The aim of the present study was to 1) evaluate post-operative quality of life, 2) compare clinical outcomes between minimally invasive and conventional open surgery, 3) evaluate the role of oxidative stress in the carcinogenesis of non-small lung cancer (NSCLC), and 4) to identify and characterise targeted agents for therapeutic and diagnostic use in surgery. For study I, pneumonectomy patients replied to 15D quality of life and baseline dyspnea questionnaires. Study III involved a prospective quality of life assessment using the 15D questionnaire after lobectomy or bi-lobectomy. Study IV was a retrospective comparison of clinical outcomes between 212 patients treated with open thoracotomy and 116 patients who underwent a minimally invasive technique. Study II measured parameters of oxidative metabolism (myeloperoxidase activity, glutathione content and NADPH oxidase activity) and DNA adducts. Study V employed the phage display method and identified a core motif for homing peptides. This method served in cell-binding, cell-localisation, and biodistribution studies. Following both pneumonectomy and lobectomy, NSCLC patients showed significantly decreased long-term quality of life. No significant correlation was noted between post-operative quality of life and pre-operative pulmonary function tests. Women suffered more from increased dyspnea after pneumonectomy which was absent after lobectomy or bi-lobectomy. Patients treated with video-assisted thoracoscopy showed significantly decreased morbidity and shorter periods of hospitalization than did open surgery patients. This improvement was achieved even though the VATS patients were older and suffered more comorbid conditions and poorer pulmonary function. No significant differences in survival were noted between these two groups. An increase in NADPH oxidase activity was noted in tumour samples of both adenocarcinoma and squamous cell carcinoma. This increase was independent from myeloperoxidase activity. Elevated glutathione content was noted in tumour tissue, especially in adenocarcinoma. After panning the clinical tumour samples with the phage display method, an amino acid sequence of ARRPKLD, the Thx, was chosen for further analysis. This method proved selective of tumour tissue in both in vitro and in vivo cell-binding assay, and biodistribution showed tumour accumulation. Because of the significantly reduced quality of life following pneumonectomy, other operative strategies should be implemented as an alternative (e.g. sleeve-lobectomy). To treat this disease, implementation of a minimally invasive surgical technique is safe, and the results showed decreased morbidity and a shorter period of hospitalisation than with thoracotomy. This technique may facilitate operative treatment of elderly patients with comorbid conditions who might otherwise be considered inoperable. Simultaneous exposure to oxidative stress and altered redox states indicates the important role of oxidative stress in the pathogenesis and malignant transformation of NSCLC. The studies showed with great specificity and with favourable biodistribution that Thx peptide is specific to NSCLC tumours. Thx thus shows promise in imaging, targeted therapy, and monitoring of treatment response.
Resumo:
A concentration dependent inhibition of 3-hydroxy-3-methylglutaryl CoA (HMG CoA) reductase was found on preincubation of microsomal preparations with diallyl disulfide, a component of garlic oil. This inhibited state was only partially reversed even with high concentrations of DTT. Glutathione, a naturally occurring reducing thiol agent, was ineffective. The substrate, HMG CoA, but not NADPH, was able to give partial protection for the DTT-dependent, but not glutathione-dependent activity. The garlic-derived diallyl disulfide is the most effective among the sulfides tested for inhibition of HMG CoA reductase. Formation of protein internal disulfides, inaccessible for reduction by thiol agents, but not of protein dimer, is likely to be the cause of this inactivation.
Resumo:
H2O2, in addition to producing highly reactive molecules through hydroxyl radicals or peroxidase action, can exert a number of direct effects on cells, organelles and enzymes. The stimulations include glucose transport, glucose incorporation into glycogen, HMP shunt pathway, lipid synthesis, release of calcium from mitochondria and of arachidonate from phospholipids, poly ADP ribosylation, and insulin receptor tyrosine kinase and pyruvate dehydrogenase activities. The inactivations include glycolysis, lipolysis, reacylation of lysophospholipids, ATP synthesis, superoxide dismutase and protein kinase C. Damages to DNA and proteoglycan and general cytotoxicity possibly through oxygen radicals were also observed. A whole new range of effects will be opened by the finding that H2O2 can act as a signal transducer in oxidative stress by oxidizing a dithiol protein to disulphide form which then activates transcription of the stress inducible genes. Many of these direct effects seem to be obtained by dithiol-disulphide modification of proteins and their active sites, as part of adaptive responses in oxidative stress.
Resumo:
Entamoeba histolytica-specific serum IgG, IgA, IgM and IgE antibodies were assayed in cases of amoebiasis in an endemic area. Patient groups consisted of amoebic liver abscess (n=18), pre-abscess hepatic amoebiasis (n=22) and amoebic colitis (n=30). Control subjects comprised 26 asymptomatic cyst passers, 13 giardiasis cases, 20 typhoid patients and 24 non-amoebic individuals. Serum IgG was assayed by ELISA, using a monoclonal anti IgG β- galactosidase (IgG β-gal) conjugate, a polyclonal avidin biotin horse radish peroxidase (AB-HRP), and a polyclonal anti IgG horse radish peroxidase (IgG HRP) conjugate. IgA and IgM were assayed by the β-gal ELISA and IgE by AB-HRP. Diagnostically significant IgG and IgA while lower IgM and IgE antibody levels were seen in extraintestinal cases. About 40% of suspected pre-abscess hepatic amoebiasis cases were confirmed by antibody estimation. All isotype levels in most dysentery cases were in the range of the controls.
Resumo:
Cell-free extracts with high 14?-hydroxylase activity were prepared from induced vegetative cell cultures of Mucor piriformis by grinding in potassium phosphate buffer (0.05 M, pH 8.0) containing glucose (0.25 M), KCl (1 mM), glutathione (1.0 mM) and glycerol (10%). Although the ideal pH for preparing the cell-free extract from vegetative cells was 8.0, the pH optimum of the hydroxylase was found to be 7.6. Microsomes (2.0 mg) prepared from the crude cell-free extract hydroxylated progesterone to 14?-hydroxyprogesterone in not, vert, similar60% yields in 30 min in the presence of NADPH and O2. Microsomes prepared from the uninduced cells did not contain any 14?-hydroxylase activity. The hydroxylase activity was inhibited to a significant extent by CO and p-chloromercuribenzoate whereas moderate inhibition was noticed in the presence of SKF-525A, metyrapone and N-methylmaleimideindicating the possible involvement of the cytochromeP-450 system in the reaction. The membrane bound hydroxylase was solubilized using Triton X-100 and the solubilized fraction contained nearly 35% of the original hydroxylase activity.
Resumo:
Ferrocenyl conjugates 2-ferrocenylimidazophenanthroline (1) and 2-ferrocenylimidazophenanthrene (2) were prepared, characterized, and their photoinduced DNA cleavage and photocytotoxic activity were studied. 2-Phenylimidazophenanthroline (3) was used as a control species. Compound 2 was characterized by X-ray crystallography. The interaction of the compounds with double-stranded calf thymus DNA (CT DNA) was studied. The compounds show good binding affinity to CT DNA with K-b values of approximately 10(5) M-1. Thermal denaturation data suggest the groove binding nature of the compounds. The redox-active compounds show poor chemical nuclease activity in the presence of hydrogen peroxide and glutathione (GSH). Compound 1 exhibits significant DNA photocleavage activity in visible light of 476 and 532 nm. Compound 3 shows only moderate DNA cleavage activity. The positive effect of the ferrocenyl moiety is demonstrated by the DNA photocleavage data. Mechanistic investigations reveal the formation of superoxide as well as hydroxyl radicals as the active species. The photocytotoxicity of the compounds in HeLa cells was studied upon irradiation with visible light (400-700 nm). Compound 1 shows efficient photocytotoxic activity with an IC50 value of 13 mu M, while compounds 2 and 3 are less active with IC50 values of > 50 and 22 mu M, respectively.
Resumo:
Cadmium (Cd) influences lipid peroxidation (LPO) by enhancing peroxidation of membrane lipids and by disturbing the antioxidant system of cells. In isolated rat hepatocytes, LPO was observed in cells incubated with Cd (50-250 mu M) for various time periods up to 90 min. The antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) were inhibited along with depletion of glutathione (GSH) in hepatocytes treated with Cd. The results show that Cd influences LPO in rat hepatocytes due to decrease in antioxidant status.
Resumo:
Oxovanadium(IV) complexes VO(L)(B)](ClO4) (1-3) of N-2-pyridylmethylidine-2-hydroxyphenylamine (HL) Schiff base and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyrido3,2-d: 2',3'-f] quinoxaline (dpq in 2) or dipyrido3,2-a: 2',3'-c] phenazine (dppz in 3), were prepared, characterized and their DNA binding property, photo-induced DNA cleavage activity and photocytotoxicity in HeLa cells studied. The crystal structure of 1 shows the presence of a VO2+ moiety in VO2N4 coordination geometry. The complexes show a d-d band at similar to 830 nm in DMF. The complexes display an oxidative V(V)-V(IV) response near 0.5 V versus SCE and a reductive V(IV)/V(III) response near -0.65 V in DMF -0.1 M TBAP. The complexes that are avid binders to CT DNA giving K-b values within 7.1 x 10(4) to 3.2 x 10(5) M-1, do not show any significant chemical nuclease activity in presence of 3-mercaptopropionic acid or glutathione. The dpq and dppz complexes are photocleavers of pUC19 DNA in UV-A light of 365 nm forming both O-1(2) and (OH)-O-center dot radicals and in near-IR light of 785 nm forming (OH)-O-center dot radicals. The dppz complex exhibits photocytotoxicity in visible light in HeLa cells (IC50 = 6.8 mu M). Flow-cytometric study on this complex shows a high sub-G1 phase in light compared to dark indicating PDT effect. (C) 2011 Elsevier B. V. All rights reserved.
Resumo:
Ferrocenyl terpyridine 3d metal complexes and their analogues, viz. [M(Fc-tpy)(2)](ClO(4))(2) (1-4), [Zn(Ph-tpy)(2)](ClO(4))(2) (5) and [Zn(Fc-dpa)(2)]X(2) (X = ClO(4), 6; PF6, 6a), where M = Fe(II) in 1, Co(II) in 2, Cu(II) in 3 and Zn(II) in 4, Fc-tpy is 4'-ferrocenyl-2,2': 6', 2 `'-terpyridine, Ph-tpy is 4'-phenyl-2,2': 6', 2 `'-terpyridine and Fc-dpa is ferrocenyl-N,N-dipicolylmethanamine, are prepared and their DNA binding and photocleavage activity in visible light studied. Complexes 2, 4, 5 and 6a that are structurally characterized by X-ray crystallography show distorted octahedral geometry with the terpyridyl ligands binding to the metal in a meridional fashion, with Fc-dpa in 6a showing a facial binding mode. The Fc-tpy complexes display a charge transfer band in the visible region. The ferrocenyl (Fc) complexes show a quasi-reversible Fc(+)-Fc redox couple within 0.48 to 0.66 V vs. SCE in DMF-0.1 M TBAP. The DNA binding constants of the complexes are similar to 10(4) M(-1). Thermal denaturation and viscometric data suggest DNA surface binding through electrostatic interaction by the positively charged complexes. Barring the Cu(II) complex 3, the complexes do not show any chemical nuclease activity in the presence of glutathione. Complexes 1-4 exhibit significant plasmid DNA photocleavage activity in visible light via a photoredox pathway. Complex 5, without the Fc moiety, does not show any DNA photocleavage activity. The Zn(II) complex 4 shows a significant PDT effect in HeLa cancer cells giving an IC(50) value of 7.5 mu M in visible light, while being less toxic in the dark (IC(50) = 49 mu M).
Resumo:
Antithyroid drugs inhibit the thyroid hormone synthesis by inactivating the thyroid peroxidase and/or iodothyronine deiodinase, which are involved in iodination and deiodination reactions. Gold(I) compounds also inhibit the thyroid hormone synthesis by interacting with the selenocysteine residue of iodothyronine deiodinase. However, the chemical reactions between these two different classes of compounds have not been studied. In this paper, we describe the interaction of therapeutic gold(I) compounds with the commonly used thiourea-based antithyroid drug, methimazole. It is observed that the gold(I) phosphine complexes (R(3)PAuCl, where R = Me, Et, Ph) react with methimazole only upon deprotonation to produce the corresponding gold(I)-thiolate complexes. Addition of PPh(3) to the gold(I)-thiolates produces (R(3)PAuPPh(3))(+) (R = Me or Et), indicating the possibility of ligand exchange reactions.
Resumo:
The present study was to investigate the effect of W. calendulacea on ischemia and reperfusion-induced cerebral injury. Cerebral ischemia was induced by occluding right and left common carotid arteries (global cerebral ischemia) for 30 min followed by reperfusion for 1 h and 4 h individually. Various biochemical alterations, produced subsequent to the application of bilateral carotid artery occlusion (BCAO) followed by reperfusion viz. increase in lipid peroxidation (LPO), hydrogen peroxide (H(2)O(2)), and decrease in reduced glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD), level in the brain tissue, Western blot analysis (Cu-Zn-SOD and CAT) and assessment of cerebral infarct size were measured. All those enzymes are markedly reversed and restored to near normal level in the groups pre-treated with W. calendulacea (250 and 500 mg/kg given orally in single and double dose/day for 10 days) in dose-dependent way. The effect of W. calendulacea had increased significantly the protein expression of copper/zinc superoxide dismutase (Cu-Zn-SOD) and CAT in cerebral ischemia. W. claendulacea was markedly decrease cerebral infarct damages but results are not statistically significant. It can be concluded that W. calendulacea possesses a neuroprotective activity against cerebral ischemia in rat.
Resumo:
Hydrogenperoxide (H2O2) is generated in mitochondria in aerobic cells as a minor product of electron transport, is inhibited selectively by phenolic acids (in animals) or salicylhydroxamate (in plants) and is regulated by hormones and environmental conditions. Failure to detect this activity is due to presence of H2O2-consuming reactions or inhibitors present in the reaction mixture. H2O2 has a role in metabolic regulation and signal transduction reactions. A number of enzymes and cellular activities are modified, mostly by oxidizing the protein-thiol groups, on adding H2O2 in mM concentrations. On complexing with vanadate, also occurring in traces, H2O2 forms diperoxovanadate (DPV), stable at physiological pH and resistant to degradation by catalase. DPV was found to substitute for H2O2 at concentrations orders of magnitude lower, and in presence of catalase, as a substrate for user reaction, horseradish peroxidase (HRP), and in inactivating glyceraldehyde-3-phosphate dehydrogenase. superoxide dismutase (SOD)-sensitive oxidation of NADH was found to operate as peroxovanadate cycle using traces of DPV and decameric vanadate (V-10) and reduces O-2 to peroxide (DPV in presence of free vanadate). This offers a model for respiratory burst. Diperoxovanadate reproduces several actions of H2O2 at low concentrations: enhances protein tyrosine phosphorylation, activates phospholipase D, produces smooth muscle contraction, and accelerates stress induced premature senescence (SIPS) and rounding in fibroblasts. Peroxovanadates can be useful tools in the studies on H2O2 in cellular activities and regulation.
Resumo:
Acetaminophen is a widely prescribed drug used to relieve pain and fever; however, it is a leading cause of drug-induced liver injury and a burden on public healthcare. In this study, hepatotoxicity in mice post oral dosing of acetaminophen was investigated using liver and sera samples with Fourier Transform Infrared microspectroscopy. The infrared spectra of acetaminophen treated livers in BALB/ mice show decrease in glycogen, increase in amounts of cholesteryl esters and DNA respectively. Rescue experiments using L-methionine demonstrate that depletion in glycogen and increase in DNA are abrogated with pre-treatment, but not post-treatment, with L-methionine. This indicates that changes in glycogen and DNA are more sensitive to the rapid depletion of glutathione. Importantly, analysis of sera identified lowering of glycogen and increase in DNA and chlolesteryl esters earlier than increase in alanine aminotransferase, which is routinely used to diagnose liver damage. In addition, these changes are also observed in C57BL/6 and Nos2(-/-) mice. There is no difference in the kinetics of expression of these three molecules in both strains of mice, the extent of damage is similar and corroborated with ALT and histological analysis. Quantification of cytokines in sera showed increase upon APAP treatment. Although the levels of Tnf alpha and Ifn gamma in sera are not significantly affected, Nos2(-/-) mice display lower Il6 but higher Il10 levels during this acute model of hepatotoxicity. Overall, this study reinforces the growing potential of Fourier Transform Infrared microspectroscopy as a fast, highly sensitive and label-free technique for non-invasive diagnosis of liver damage. The combination of Fourier Transform Infrared microspectroscopy and cytokine analysis is a powerful tool to identify multiple biomarkers, understand differential host responses and evaluate therapeutic regimens during liver damage and, possibly, other diseases.
Resumo:
Objective: The present study was undertaken to evaluate the antitumor and antioxidant status of ethanol extract of Terminalia catappa leaves against Ehrlich ascites carcinoma (EAC) in Swiss albino mice. Materials and Methods: The leaves powder was extracted with Soxhlet apparatus and subjected to hot continuous percolation using ethanol (95% v/v). Tumor bearing animals was treated with 50 and 200 mg/kg of ethanol extract. EAC induced in mice by intraperitoneal injection of EAC cells 1 x 10(6) cells/mice. The study was assed using life span of EAC-bearing hosts, hematological parameters, volume of solid tumor mass and status of antioxidant enzymes such as lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) activities. Total phenolics and flavonoids contents from the leaves extract were also determined. Results: Total phenolics and flavonoids contents from the leaves extract were found 354.02 and 51.67 mg/g extract. Oral administration of ethanol extract of T. catappa (50 and 200 mg/kg) increased the life span (27.82% and 60.59%), increased peritoneal cell count (8.85 +/- 0.20 and 10.37 +/- 0.26) and significantly decreased solid tumor mass (1.16 +/- 0.14 cm(2)) at 200 mg/kg as compared with EAC-tumor bearing mice (P < 0.01). Hematological profile including red blood cell count, white blood cell count, hemoglobin (11.91 +/- 0.47 % g) and protein estimation were found to be nearly normal levels in extract-treated mice compared with tumor bearing control mice. Treatment with T. catappa significantly decreased levels of LPO and GSH, and increased levels of SOD and CAT activity (P < 0.01). Conclusion: T. catappa exhibited antitumor effect by modulating LPO and augmenting antioxidant defense systems in EAC bearing mice. The phenolic and flavonoid components in this extract may be responsible for antitumor activity.