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El-Naggar, Sabry Ali, Karim Samy El-Said, Mona Elwan, Maysa Mobasher, Fotouh Mansour, Mohamed Elbakry, and Doaa Ibrahim Kabil. "Toxicity of bean cooking media containing EDTA in mice." Toxicology and Industrial Health 36, no. 6 (June 2020): 436–45. http://dx.doi.org/10.1177/0748233719893178.
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The possible renal and hepatic toxicities of ethylenediaminetetraacetic acid (EDTA) in bean cooking media were studied using 100 male albino mice. Two sublethal doses of EDTA were used to explore their toxic effects; 20 mg/kg and 200 mg/kg, which corresponded to 1/100th and 1/10th of LD50, respectively. Accordingly, the toxicity study was performed using 50 mice, divided into five groups ( n = 10/group) as follows: group 1 (Gp1) served as a negative control and was orally administered normal saline; group 2 (Gp2) was administered the bean cooking medium; group 3 (Gp3) was administered EDTA (200 mg/kg); group 4 (Gp4) was administered bean cooking medium containing 20 mg/kg of EDTA; and group 5 (Gp5) was administered bean cooking medium containing 200 mg/kg of EDTA. The results showed no significant changes in liver and kidney functions in Gp2 while Gp3, Gp4, and Gp5 exhibited significant increases in adverse liver and kidney function markers. Hematocrit values were significantly decreased in Gp3 and Gp5, while the total white blood cells counts were significantly decreased in Gp3 and significantly increased in Gp5. The number of platelets was decreased in Gp3, Gp4, and Gp5. The blood levels of sodium (Na+), iron (Fe2+), and calcium (Ca2+) were decreased in Gp3, Gp4, and Gp5 due to the chelating effects of EDTA. The hepatic and renal architectures were disorganized in Gp3, Gp4, and Gp5 with some hemorrhagic manifestations in livers and kidneys of mice. These results demonstrate that EDTA in bean cooking is harmful in mice under the conditions of this study, and the potentially harmful effects in humans supports restricting its use.
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Reinke, Emily N., Dede N. Ekoue, Soumen Bera, Nadim Mahmud, and Alan M. Diamond. "Translational Regulation of GPx-1 and GPx-4 by the mTOR Pathway." PLoS ONE 9, no. 4 (April 1, 2014): e93472. http://dx.doi.org/10.1371/journal.pone.0093472.
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Qin, Shun Yi, Fu Chen, Yong Gang Guo, Bao Xia Huang, Jiang Bing Zhang, and Ji Fei Ma. "Effects of Nano-Selenium on Kindey Selenium Contents, Glutathione Peroxidase Activities and GPx-1 mRNA Expression in Mice." Advanced Materials Research 1051 (October 2014): 383–87. http://dx.doi.org/10.4028/www.scientific.net/amr.1051.383.
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The experiment was conducted to evaluate kindey selenium status, glutathione peroxidase (GPx) activity and GPx-1 expression in mice fed with nanoselenium. Sixty KM mice, female and male in half, were randomly divided into control, sodium selenite and nanoselenium groups. 0.5 milliliter of water, sodium selenite (2 μg Se/mL) and nanoselenium (2 μg Se/mL) were respectively supplemented to the three groups in oral (ig) every day. Whole experiment lasted for 28 days. Kindey selenium contents, GPx activities and GPx-1 mRNA expression were analyzed at experiment trrmination. The results showed that kindey selenium contents and GPx activities in nanoselenium group and sodium selenite group were very significantly higher than those in control group (P<0.01); kindey GPx activities in nanoselenium group were significantly higher than that in sodium selenite group (P<0.05). Kindey mRNA expression of GPx-1 was approx 166% higher in nanoselenium group and approx 157% higher in sodium selenite group than that in control group. Kindey mRNA expression of GPx-1 was approx 3.50 % higher in nanoselenium group than that in sodium selenite group. The results indicated that nanoselenium supplementation could significantly enhance kindey selenium contents, GPx activities and GPx-1 mRNA expression in mice, nanoselenium was more available than sodium selenite in increasing kindey selenium contents, GPx activities and GPx-1 mRNA expression in mice.
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Chada, S., C. Whitney, and PE Newburger. "Post-transcriptional regulation of glutathione peroxidase gene expression by selenium in the HL-60 human myeloid cell line." Blood 74, no. 7 (November 15, 1989): 2535–41. http://dx.doi.org/10.1182/blood.v74.7.2535.2535.
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Abstract We have used a cloned cDNA for the major human selenoprotein, glutathione peroxidase (GPx), to assess the mode of regulation of human GPx gene (GPX-1) expression by selenium. When the HL-60 human myeloid cell line is grown in a selenium-deficient medium, GPx enzymatic activity decreases 30-fold compared with selenium-replete cells. Upon return to a medium containing selenium in the form of selenite, GPx activity in the cells starts to increase within 48 hours and reaches maximal (selenium-replete) levels at 7 days. Steady-state immunoreactive protein levels correlate with enzymatic activity. Cycloheximide inhibits the rise in GPx activity that accompanies selenium replenishment, indicating that protein synthesis is required for the increase. However, GPx mRNA levels and the rate of transcription of the human GPx gene change very little and thus appear to be independent of the selenium supply. Thus the human GPx gene appears to be regulated post-transcriptionally, probably cotranslationally, in response to selenium availability.
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Chada, S., C. Whitney, and PE Newburger. "Post-transcriptional regulation of glutathione peroxidase gene expression by selenium in the HL-60 human myeloid cell line." Blood 74, no. 7 (November 15, 1989): 2535–41. http://dx.doi.org/10.1182/blood.v74.7.2535.bloodjournal7472535.
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We have used a cloned cDNA for the major human selenoprotein, glutathione peroxidase (GPx), to assess the mode of regulation of human GPx gene (GPX-1) expression by selenium. When the HL-60 human myeloid cell line is grown in a selenium-deficient medium, GPx enzymatic activity decreases 30-fold compared with selenium-replete cells. Upon return to a medium containing selenium in the form of selenite, GPx activity in the cells starts to increase within 48 hours and reaches maximal (selenium-replete) levels at 7 days. Steady-state immunoreactive protein levels correlate with enzymatic activity. Cycloheximide inhibits the rise in GPx activity that accompanies selenium replenishment, indicating that protein synthesis is required for the increase. However, GPx mRNA levels and the rate of transcription of the human GPx gene change very little and thus appear to be independent of the selenium supply. Thus the human GPx gene appears to be regulated post-transcriptionally, probably cotranslationally, in response to selenium availability.
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van der REST, Benoît, Norbert ROLLAND, Anne-Marie BOISSON, Myriam FERRO, Richard BLIGNY, and Roland DOUCE. "Identification and characterization of plant glycerophosphodiester phosphodiesterase." Biochemical Journal 379, no. 3 (May 1, 2004): 601–7. http://dx.doi.org/10.1042/bj20031489.
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GPX-PDE (glycerophosphodiester phosphodiesterase; EC 3.1.4.46) is a relatively poorly characterized enzyme that catalyses the hydrolysis of various glycerophosphodiesters (glycerophosphocholine, glycerophosphoethanolamine, glycerophosphoglycerol, glycerophosphoserine and bis-glycerophosphoglycerol), releasing sn-glycerol 3-phosphate and the corresponding alcohol. In a previous study, we demonstrated the existence of a novel GPX-PDE in the cell walls and vacuoles of plant cells. Since no GPX-PDE had been identified in any plant organism, the purification of GPX-PDE from carrot cell walls was attempted. After extraction of cell wall proteins from carrot cell suspension cultures with CaCl2, GPX-PDE was purified up to 2700-fold using, successively, ammonium sulphate precipitation, gel filtration and concanavalin A–Sepharose. Internal sequence analysis of a 55 kDa protein identified in the extract following 2700-fold purification revealed strong similarity to the primary sequence of GLPQ, a bacterial GPX-PDE. To confirm the identity of plant GPX-PDE, an Arabidopsis thaliana cDNA similar to that encoding the bacterial GPX-PDE was cloned and overexpressed in a bacterial expression system, and was used to raise antibodies against the putative Arabidopsis thaliana GPX-PDE. Immunochemical assays performed on carrot cell wall proteins extracted by CaCl2 treatment showed a strong correlation between GPX-PDE activity and detection of the 55 kDa protein, validating the identity of the plant GPX-PDE. Finally, various properties of the purified enzyme were investigated. GPX-PDE is a multimeric enzyme, specific for glycerophosphodiesters, exhibiting a Km of 36 µM for glycerophosphocholine and active within a wide pH range (from 4 to 10). Since these properties are similar to those of GLPQ, the bacterial GPX-PDE, the similarities between plant and bacterial enzymes are also discussed.
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Forgione, Marc A., Norbert Weiss, Stanley Heydrick, André Cap, Elizabeth S. Klings, Charlene Bierl, Robert T. Eberhardt, Harrison W. Farber, and Joseph Loscalzo. "Cellular glutathione peroxidase deficiency and endothelial dysfunction." American Journal of Physiology-Heart and Circulatory Physiology 282, no. 4 (April 1, 2002): H1255—H1261. http://dx.doi.org/10.1152/ajpheart.00598.2001.
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Cellular glutathione peroxidase (GPx-1) is the most abundant intracellular isoform of the GPx antioxidant enzyme family. In this study, we hypothesized that GPx-1 deficiency directly induces an increase in vascular oxidant stress, with resulting endothelial dysfunction. We studied vascular function in a murine model of homozygous deficiency of GPx-1 (GPx-1−/−). Mesenteric arterioles of GPx-1−/− mice demonstrated paradoxical vasoconstriction to β-methacholine and bradykinin, whereas wild-type (WT) mice showed dose-dependent vasodilation in response to both agonists. One week of treatment of GPx-1−/− mice withl-2-oxothiazolidine-4-carboxylic acid (OTC), which increases intracellular thiol pools, resulted in restoration of normal vascular reactivity in the mesenteric bed of GPx-1−/−mice. We observed an increase of the isoprostane iPF2α-III, a marker of oxidant stress, in the plasma and aortas of GPx-1−/− mice compared with WT mice, which returned toward normal after OTC treatment. Aortic sections from GPx-1−/− mice showed increased binding of an anti-3-nitrotyrosine antibody in the absence of frank vascular lesions. These findings demonstrate that homozygous deficiency of GPx-1 leads to impaired endothelium-dependent vasodilator function presumably due to a decrease in bioavailable nitric oxide and to increased vascular oxidant stress. These vascular abnormalities can be attenuated by increasing bioavailable intracellular thiol pools.
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Cook, Donald, Howard Hill, Michael Snyder, Philip McMahon, and David Kinker. "The Detection of Antibodies to the Glycoprotein X Antigen of Pseudorabies Virus." Journal of Veterinary Diagnostic Investigation 2, no. 1 (January 1990): 24–28. http://dx.doi.org/10.1177/104063879000200105.
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The persistence of antibodies to glycoprotein X (gpX) in the serum of pigs experimentally infected with pseudorabies virus (PRV) was determined using an anti-gpX enzyme-linked immunosorbent assay (ELISA). Antibodies to gpX were detected for at least 365 days postchallenge in nonvaccinated pigs. Previous sensitization of pigs by vaccination with S/PRV had no apparent effect on the antibody response of pigs to gpX postchallenge. In determining previous exposure of pigs to PRV strains containing the gpX gene, the anti-gpX ELISA was highly specific, but its sensitivity was lower than the standard serological procedures currently used for detecting PRV antibodies.
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Lubos, Edith, Neil J. Kelly, Scott R. Oldebeken, Jane A. Leopold, Ying-Yi Zhang, Joseph Loscalzo, and Diane E. Handy. "Glutathione Peroxidase-1 Deficiency Augments Proinflammatory Cytokine-induced Redox Signaling and Human Endothelial Cell Activation." Journal of Biological Chemistry 286, no. 41 (August 18, 2011): 35407–17. http://dx.doi.org/10.1074/jbc.m110.205708.
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Glutathione peroxidase-1 (GPx-1) is a crucial antioxidant enzyme, the deficiency of which promotes atherogenesis. Accordingly, we examined the mechanisms by which GPx-1 deficiency enhances endothelial cell activation and inflammation. In human microvascular endothelial cells, we found that GPx-1 deficiency augments intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression by redox-dependent mechanisms that involve NFκB. Suppression of GPx-1 enhanced TNF-α-induced ROS production and ICAM-1 expression, whereas overexpression of GPx-1 attenuated these TNF-α-mediated responses. GPx-1 deficiency prolonged TNF-α-induced IκBα degradation and activation of ERK1/2 and JNK. JNK or NFκB inhibition attenuated TNF-α induction of ICAM-1 and VCAM-1 expression in GPx-1-deficient and control cells, whereas ERK1/2 inhibition attenuated only VCAM-1 expression. To analyze further signaling pathways involved in GPx-1-mediated protection from TNF-α-induced ROS, we performed microarray analysis of human microvascular endothelial cells treated with TNF-α in the presence and absence of GPx-1. Among the genes whose expression changed significantly, dual specificity phosphatase 4 (DUSP4), encoding an antagonist of MAPK signaling, was down-regulated by GPx-1 suppression. Targeted DUSP4 knockdown enhanced TNF-α-mediated ERK1/2 pathway activation and resulted in increased adhesion molecule expression, indicating that GPx-1 deficiency may augment TNF-α-mediated events, in part, by regulating DUSP4.
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Swenson, Sabrina L., Janis McMillen, and Howard T. Hill. "Diagnostic Compatibility of a Thymidine Kinase, Inverted Repeat, gI, and gpX Modified Live Gene-Deleted PRV Vaccine with Three Differential ELISAs." Journal of Veterinary Diagnostic Investigation 5, no. 3 (July 1993): 347–50. http://dx.doi.org/10.1177/104063879300500307.
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The differential pseudorabies virus (PRV) vaccines currently in use in the USA have deletions of the genes coding for the glycoprotein I (gl) and/or glycoprotein X (gpX). The absence of gI and/or gpX allow for the serologic differentiation of vaccinated swine from PRV-infected swine using differential enzyme-linked immunosorbent assays (ELISAs). A newly developed pseudorabies vaccine virus has 4 deletions of the viral genome: the genes coding for gI, gpX, and thymidine kinase and a portion of the repeat region to attenuate the virus. The purpose of this work was to evaluate the diagnostic compatibility of the gI/gpX gene-deleted vaccine with 3 differential vaccines and 3 differential ELISAs currently in use. Pigs vaccinated 3 times with the gI/gpX gene-deleted vaccine remained seronegative on the 3 differential ELISAs tested. Pigs previously vaccinated with either a gI or gpX gene-deleted vaccine and then vaccinated with the gI/gpX gene-deleted vaccine remained seronegative on the respective gI or gpX differential assay.
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Alameda, Luis, Margot Fournier, Ines Khadimallah, Alessandra Griffa, Martine Cleusix, Raoul Jenni, Carina Ferrari, et al. "Redox dysregulation as a link between childhood trauma and psychopathological and neurocognitive profile in patients with early psychosis." Proceedings of the National Academy of Sciences 115, no. 49 (November 19, 2018): 12495–500. http://dx.doi.org/10.1073/pnas.1812821115.
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Exposure to childhood trauma (CT) increases the risk for psychosis and affects the development of brain structures, possibly through oxidative stress. As oxidative stress is also linked to psychosis, it may interact with CT, leading to a more severe clinical phenotype. In 133 patients with early psychosis (EPP), we explored the relationships between CT and hippocampal, amygdala, and intracranial volume (ICV); blood antioxidant defenses [glutathione peroxidase (GPx) and thioredoxin/peroxiredoxin (Trx/Prx)]; psychopathological results; and neuropsychological results. Nonadjusted hippocampal volume correlated negatively with GPx activity in patients with CT, but not in patients without CT. In patients with CT with high GPx activity (high-GPx+CT), hippocampal volume was decreased compared with that in patients with low-GPx+CT and patients without CT, who had similar hippocampal volumes. Patients with high-GPx+CT had more severe positive and disorganized symptoms than other patients. Interestingly, Trx and oxidized Prx levels correlated negatively with GPx only in patients with low-GPx+CT. Moreover, patients with low-GPx+CT performed better than other patients on cognitive tasks. Discriminant analysis combining redox markers, hippocampal volume, clinical scores, and cognitive scores allowed for stratification of the patients into subgroups. In conclusion, traumatized EPP with high peripheral oxidation status (high-GPx activity) had smaller hippocampal volumes and more severe symptoms, while those with lower oxidation status (low-GPx activity) showed better cognition and regulation of GPx and Trx/Prx systems. These results suggest that maintained regulation of various antioxidant systems allowed for compensatory mechanisms preventing long-term neuroanatomical and clinical impacts. The redox marker profile may thus represent important biomarkers for defining treatment strategies in patients with psychosis.
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STRAIF, Dietlind, Oliver WERZ, Roland KELLNER, Ute BAHR, and Dieter STEINHILBER. "Glutathione peroxidase-1 but not -4 is involved in the regulation of cellular 5-lipoxygenase activity in monocytic cells." Biochemical Journal 349, no. 2 (July 10, 2000): 455–61. http://dx.doi.org/10.1042/bj3490455.
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In contrast to neutrophils or B-lymphocytes, cells of the monocytic lineage like rat macrophages, human peripheral blood monocytes and Mono Mac 6 cells contain a strong inhibitor of 5-lipoxygenase (5-LO) activity, which scavenges hydroperoxides and inhibits 5-LO activity in broken-cell preparations in the absence of exogenously added thiols. Chromatographic purification of the inhibitor from the human monocytic cell line Mono Mac 6 and amino acid sequence analysis revealed that the inhibitory factor is glutathione peroxidase-1 (GPx-1). In contrast to the peroxidase activity of GPx-1, 5-LO inhibition by GPx-1 was supported by β-mercaptoethanol and there was no absolute requirement for millimolar concentrations of glutathione or dithiothreitol. These cofactor characteristics suggest that both activities address distinct catalytic properties of GPx-1. 5-LO inhibition by GPx-1 was not due to direct GPx-5-LO protein-protein interactions, since GPx-1 did not bind to immobilized 5-LO. Interestingly, 5-LO derived from granulocytes was significantly more resistant against GPx-1 inhibition than B-lymphocytic 5-LO, which correlates with the respective cellular 5-LO activities. In summary, the data suggest that, in addition to previously reported phospholipid hydroperoxide glutathione peroxidase (GPx-4), GPx-1 is an efficient inhibitor of 5-LO even at low thiol concentrations, and is involved in the regulation of cellular 5-LO activity in various cell types.
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Djordjevic, V., and M. Knezevic. "Low erythrocyte glutathione peroxidase activity in schizophrenic patients is mediated by gender, the number of episodes, disease duration and drug treatment." European Psychiatry 33, S1 (March 2016): S246—S247. http://dx.doi.org/10.1016/j.eurpsy.2016.01.625.
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IntroductionInconsistent data showed that erythrocyte glutathione peroxidase (GPx) activity in schizophrenics is altered.AimThe aim of this study was to evaluate whether some of the demographic, clinical and therapeutic factors had any significant impact on erythrocyte GPx activity in patients with schizophrenia.MethodsThis study included 68 schizophrenic patients and 59 healthy individuals. GPx activity was tested related to patient age, gender, heredity, the onset of the disease, the duration of the disease, the number of episodes, PANSS scores and drug treatment. GPx activity was determined in erythrocyte hemolysates by Ransel commercially available test.ResultsErythrocyte GPx activity was significantly lower in patients with schizophrenia than in controls. Male patients had significantly lower GPx activity in comparison with those in female ones. Heredity negative patients showed significantly lower enzyme activity compared to control values. Significantly lower GPx activity was obtained independently of the onset of the disease. The patient group having more than one psychotic episode also showed significantly lower GPx activity compared to the control group. The disease duration of more than 1 year caused a significant decrease in enzyme activity. There was a significant difference in GPx activity between patients with different PANSS scores. In patients treated with second generation antipsychotics and in those treated with both first and second generation antipsychotics, GPx activity was significantly lower than in controls.ConclusionThis study shows that the low erythrocyte GPx activity in schizophrenics depends on patient gender, the number of episodes, disease duration and drug treatment.Disclosure of interestThe authors have not supplied their declaration of competing interest.
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Cubas-Gaona, Liliana L., Patricia de Francisco, Ana Martín-González, and Juan Carlos Gutiérrez. "Tetrahymena Glutathione Peroxidase Family: A Comparative Analysis of These Antioxidant Enzymes and Differential Gene Expression to Metals and Oxidizing Agents." Microorganisms 8, no. 7 (July 5, 2020): 1008. http://dx.doi.org/10.3390/microorganisms8071008.
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In the present work, an extensive analysis of the putative glutathione peroxidases (GPx) of the eukaryotic microorganism model Tetrahymena thermophila is carried out. A comparative analysis with GPx present in other Tetrahymena species and other very taxonomically diverse ciliates is also performed. A majority of ciliate GPx have replaced the selenocysteine (Sec) by Cys in its catalytic center, so they can be considered as phospholipid hydroperoxide glutathione peroxidases (PHGPx). Selenocysteine insertion sequence (SECIS) elements have been detected in several ciliate GPx that do not incorporate Sec in their amino acid sequences, and conversely, in other ciliate GPx with Sec, no SECIS elements are detected. These anomalies are analyzed and discussed. From the phylogenetic analysis using the ciliate GPx amino acid sequences, the existence of extensive intra- and interspecific gene duplications that produced multiple GPx isoforms in each species is inferred. The ancestral character of the selenoproteins is also corroborated. The analysis by qRT-PCR of six selected T. thermophila GPx genes has shown a quantitative differential expression between them, depending on the stressor (oxidizing agents, apoptotic inducer or metals) and the time of exposure.
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Hu, Ying, Graeme H. McIntosh, Richard K. Le Leu, and Graeme P. Young. "Selenium-enriched milk proteins and selenium yeast affect selenoprotein activity and expression differently in mouse colon." British Journal of Nutrition 104, no. 1 (March 29, 2010): 17–23. http://dx.doi.org/10.1017/s0007114510000309.
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Certain forms of dietary Se may have an advantage in improving Se status and reducing cancer risk. The present study compared the effects of an Se-enriched milk protein product (dairy-Se) with an Se yeast (yeast-Se) on selenoprotein activity and expression in the mouse colon. Mice were fed four diets for 4 weeks: a control milk protein diet (Se at 0·068 parts per million (ppm)), dairy-Se diets with Se at 0·5 and 1 ppm, and a yeast-Se diet with Se at 1 ppm. Cytosolic glutathione peroxidase-1 (GPx-1) activity, mRNA of selenoprotein P (SeP), GPx-1, gastrointestinal glutathione peroxidase-2 (GPx-2) and thioredoxin reductase-1 (TrxR-1) were examined in the mouse colon. Dairy-Se diets did not significantly affect GPx-1 mRNA and GPx-1 activity but produced a dose-dependent increase in SeP and GPx-2 mRNA, with a significantly higher level achieved at 1 ppm Se (P < 0·05). Yeast-Se at 1 ppm significantly increased GPx-1 mRNA and GPx-1 activity (P < 0·01) but not GPx-2 mRNA. Neither Se supplement had any effect on TrxR-1. The present study indicates that selenoprotein levels in the mouse colon are regulated differently depending on the Se supplement. As we have previously shown that dairy-Se at 1 ppm was protective against colorectal cancer (CRC) in an azoxymethane-induced CRC mouse model, this up-regulation of colonic GPx-2 and SeP with Se supplementation may be crucial to its chemopreventive action.
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Zinellu, Elisabetta, Angelo Zinellu, Maria Carmina Pau, Barbara Piras, Alessandro G. Fois, Sabrina Mellino, Ciriaco Carru, Arduino A. Mangoni, and Pietro Pirina. "Glutathione Peroxidase in Stable Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis." Antioxidants 10, no. 11 (October 30, 2021): 1745. http://dx.doi.org/10.3390/antiox10111745.
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Chronic obstructive pulmonary disease (COPD) is a progressive disease that is characterized by a state of persistent inflammation and oxidative stress. The presence of oxidative stress in COPD is the result of an imbalance between pro-oxidant and antioxidant mechanisms. The aim of this review was to investigate a possible association between glutathione peroxidase (GPx), a key component of antioxidant defense mechanisms, and COPD. A systematic search for relevant studies was conducted in the electronic databases PubMed, Web of Science, Scopus, and Google Scholar, from inception to June 2021. Standardized mean differences (SMDs) were used to express the differences in GPx concentrations between COPD patients and non-COPD subjects. Twenty-four studies were identified. In 15 studies assessing whole blood/erythrocytes (GPx isoform 1), the pooled results showed that GPx concentrations were significantly lower in patients with COPD (SMD = −1.91, 95% CI −2.55 to −1.28, p < 0.001; moderate certainty of evidence). By contrast, in 10 studies assessing serum/plasma (GPx isoform 3), the pooled results showed that GPx concentrations were not significantly different between the two groups (very low certainty of evidence). The concentration of GPx-1, but not GPx-3, is significantly lower in COPD patients, suggesting an impairment of antioxidant defense mechanisms in this group.
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Hassan, A. M. "Glutathione peroxidase activity in blood cells from aspirin-induced asthma patients." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 40, no. 4 (July 1, 2003): 369–73. http://dx.doi.org/10.1258/000456303766477002.
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Aspirin and other inhibitors of cyclo-oxygenase precipitate acute bronchospasm in about 10% of adult asthmatics. It has been assumed that cyclo-oxygenase is involved in the pathogenesis of bronchospasm, but the precise mechanism remains poorly understood. The oxygenation products of arachidonic acid include hydroperoxyeicosatetraenoic acid and cyclic endoperoxides. Glutathione peroxidase (GPX) reduces semi-stable hydroperoxides to less reactive alcohols and removes H2O2 involved in inflammation. GPX could, therefore, modulate oxidation of arachidonic acid in the cyclo-oxygenase and lipoxygenase pathways, but the involvement of GPX in the pathogenesis of asthma has received little attention. We measured GPX activity in platelets, peripheral blood lymphocytes (PBL), red blood cells (RBC) and plasma from 13 patients with aspirin-induced asthma (AIA). Age- and sex-matched healthy individuals served as the comparison group. The patients had significantly higher GPX activity in platelets (P = 0·05) and tended to have high GPX activity (P = 0·08) in plasma but not in RBC or PBL. The results suggest that the increased GPX activity may be an adaptive advantage in AIA to protect against increased free radical production by inflammatory cells. That the higher GPX activity was not evident in all cell types studied may indicate a differential role played by them as effector cells in the pathogenesis of AIA.
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Kobayashi, Hironori, Morihiro Matsuda, Atsunori Fukuhara, Ryutaro Komuro, and Iichiro Shimomura. "Dysregulated glutathione metabolism links to impaired insulin action in adipocytes." American Journal of Physiology-Endocrinology and Metabolism 296, no. 6 (June 2009): E1326—E1334. http://dx.doi.org/10.1152/ajpendo.90921.2008.
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Oxidative stress plays an important role in obesity-related metabolic diseases. Glutathione peroxidase (GPX) is an antioxidant enzyme downregulated in adipose tissue of obese mice. However, the role of GPX in adipocytes remains elusive. The objective of this study was to clarify the pathophysiological changes in GPX activity and glutathione metabolism and their roles in the pathogenesis of insulin resistance in adipocytes. To achieve this goal, we measured cellular GPX activity, glutathione (GSH) contents, GSH/GSSG ratio, and mRNA expression of γ-glutamylcysteine synthetase (γ-GCS), a rate-limiting enzyme for de novo GSH synthesis, in adipose tissue of control and ob/ob mice and in 3T3-L1 adipocytes treated with insulin, H2O2, free fatty acid (FFA), or TNFα. Furthermore, we investigated the effects of GPX inhibition with a specific GPX inhibitor or RNA interference against GPX, H2O2, and reduced GSH on insulin signaling in 3T3-L1 adipocytes. ob/ob Mice showed not only a decrease in cellular activity of GPXs (GPX1, -4, and -7) but also an increase in γ-GCS expression, resulting in increased GSH contents in adipose tissue. These alterations in glutathione metabolism were also observed during differentiation of 3T3-L1 cells and their exposure to insulin, FFA, or H2O2. Inhibition of GPX activity, addition of GSH, and H2O2resulted in impaired insulin signaling in 3T3-L1 adipocytes. These results suggest that decreased GPX activity and increased γ-GCS expression lead to overaccumulation of GSH, which might be involved in the pathogenesis of insulin resistance in obesity.
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Shimura, Tsutomu, Rina Shiga, Megumi Sasatani, Kenji Kamiya, and Akira Ushiyama. "Melatonin and MitoEbselen-2 Are Radioprotective Agents to Mitochondria." Genes 14, no. 1 (December 23, 2022): 45. http://dx.doi.org/10.3390/genes14010045.
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Mitochondria are responsible for controlling cell death during the early stages of radiation exposure, but their perturbations are associated with late effects of radiation-related carcinogenesis. Therefore, it is important to protect mitochondria to mitigate the harmful effects of radiation throughout life. The glutathione peroxidase (GPx) enzyme is essential for the maintenance of mitochondrial-derived reactive oxygen species (ROS) levels. However, radiation inactivates the GPx, resulting in metabolic oxidative stress and prolonged cell injury in irradiated normal human fibroblasts. Here, we used the GPx activator N-acetyl-5-methoxy-tryptamine (melatonin) and a mitochondria-targeted mimic of GPx MitoEbselen-2 to stimulate the GPx. A commercial GPx activity assay kit was used to measure the GPx activity. ROS levels were determined by using some ROS indicators. Protein expression associated with the response of mitochondria to radiation was assessed using immunostaining. Concurrent pre-administration or post-administration of melatonin or MitoEbselen-2 with radiation maintained GPx activity and ROS levels and suppressed mitochondrial radiation responses associated with cellular damage and radiation-related carcinogenesis. In conclusion, melatonin and MitoEbselen-2 prevented radiation-induced mitochondrial injury and metabolic oxidative stress by targeting mitochondria. These drugs have the potential to protect against acute radiation injury and late effects of carcinogenesis in a variety of radiation scenarios assuming pre-administration or post-administration.
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Yu, Haibo, Chi Wang, Wei Deng, Guohao Liu, Sha Liu, and Hong Ji. "Characterization and Expression Profiling of Glutathione Peroxidase 1 gene (GPX1) and Activity of GPX in Onychostoma macrolepis suffered from Thermal Stress." Turkish Journal of Fisheries and Aquatic Sciences 21, no. 11 (July 14, 2021): 541–51. http://dx.doi.org/10.4194/1303-2712-v21_11_02.
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In this study, full-length cDNA of glutathione peroxidases 1 (GPX1) of Onychostoma macrolepis was cloned by RACE, and expression of GPX1 and activity of GPX in O. macrolepis suffered from heat stress were analyzed. Compared with the control group (24°C), the experimental fish were stressed for 0, 1, 3, 6, 12, 24, and 48 hours at the heated water (30°C). Liver had highest level and response speed in GPX1 expression among various tissues after heat stress, indicated that liver was the highest sensitive tissue to heat stress. When the water was raised to the heating temperature (30°C), the GPX activity decreased in fish serum, and the consumption of GPX eliminated the increase of ROS caused by heat stress within 3h. However, after 6h and 12h stress at 30°C, GPX activity was significantly higher than that at 0h (P<0.05), which is due to the rapid response of GPX to heat stress. In summary, fish showed a transient stress response and was acclimated to the new temperature after 24 h according to the overall expression of the GPX1 and the serum GPX activity, and both GPX1 and GPX play crucial roles in this process.
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Trenz, Thomaz Stumpf, Camila Luiza Delaix, Andreia Carina Turchetto-Zolet, Marcel Zamocky, Fernanda Lazzarotto, and Márcia Margis-Pinheiro. "Going Forward and Back: The Complex Evolutionary History of the GPx." Biology 10, no. 11 (November 12, 2021): 1165. http://dx.doi.org/10.3390/biology10111165.
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There is large diversity among glutathione peroxidase (GPx) enzymes regarding their function, structure, presence of the highly reactive selenocysteine (SeCys) residue, substrate usage, and reducing agent preference. Moreover, most vertebrate GPxs are very distinct from non-animal GPxs, and it is still unclear if they came from a common GPx ancestor. In this study, we aimed to unveil how GPx evolved throughout different phyla. Based on our phylogenetic trees and sequence analyses, we propose that all GPx encoding genes share a monomeric common ancestor and that the SeCys amino acid was incorporated early in the evolution of the metazoan kingdom. In addition, classical GPx and the cysteine-exclusive GPx07 have been present since non-bilaterian animals, but they seem to have been lost throughout evolution in different phyla. Therefore, the birth-and-death of GPx family members (like in other oxidoreductase families) seems to be an ongoing process, occurring independently across different kingdoms and phyla.
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Holley, Ana, Janet Pitman, John Miller, Scott Harding, and Peter Larsen. "Glutathione peroxidase activity and expression levels are significantly increased in acute coronary syndromes." Journal of Investigative Medicine 65, no. 5 (March 15, 2017): 919–25. http://dx.doi.org/10.1136/jim-2016-000361.
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High levels of the antioxidant enzyme, glutathione peroxidase (GPx), have been associated with improved outcomes following acute coronary syndromes (ACS), suggesting a protective role. How GPx levels are altered with coronary disease is not clearly established. This study examined GPx activity, protein, and mRNA levels in healthy controls, patients with stable coronary artery disease (CAD), and patients with ACS. We studied 20 individuals from each of the healthy control, stable CAD, and ACS groups. GPx activity and protein levels, along with oxidized low-density lipoprotein (oxLDL) were assayed in plasma. GPx mRNA levels from whole blood were quantified using real-time PCR. Levels of GPx activity in the plasma were higher in ACS (109±7.7 U/mL) compared with patients with stable CAD (95.2±16.4 U/mL, p<0.01) and healthy controls (87.6±8.3 U/mL, p<0.001). Plasma GPx protein levels were also elevated in ACS (21.6±9.5 µg/mL) compared with patients with stable CAD (16.5±2.8 µg/mL, p<0.05) and healthy controls (16.3±5.3 µg/mL, p<0.05). Levels ofGPX1,GPX3, andGPX4mRNA were significantly higher in the patients with ACS. Levels of oxLDL were also significantly higher in patients with ACS (61.9±22.2 U/L) than in patients with stable CAD (47.8±10.4 U/L, p<0.05) and healthy controls (48.9±11.9 U/L, p<0.05). Levels of oxLDL, GPx activity, protein, and mRNA are all significantly higher in patients with ACS compared with patients with stable CAD and healthy controls. These findings suggest that GPx may be upregulated in response to a change in oxidative stress during an ACS.
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Sies, Helmut, Lars-Oliver Klotz, Victor S. Sharov, Annika Assmann, and Karlis Briviba. "Protection against Peroxynitrite by Selenoproteins." Zeitschrift für Naturforschung C 53, no. 3-4 (April 1, 1998): 228–32. http://dx.doi.org/10.1515/znc-1998-3-412.
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Abstract Cellular defense against excessive peroxynitrite generation is required to protect against DNA strand-breaks and mutations and against interference with protein tyrosine-based sig naling and other protein functions due to formation of 3-nitrotyrosine. We recently demon strated a role of selenium-containing enzymes catalyzing peroxynitrite reduction. Glutathione peroxidase (GPx) protected against the oxidation of dihydrorhodamine 123 (D H R) by perox ynitrite more effectively than ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one), a selenoor-ganic compound exhibiting a high second-order rate constant for the reaction with peroxynit rite, 2 × 106 M-1 S-1. The maintenance of protection by GPx against peroxynitrite requires GSH as reductant. Similarly, selenomethionine but not selenomethionine oxide exhibited inhibition of rhodamine 123 formation from DHR caused by peroxynitrite. In steady-state experiments, in which peroxynitrite was infused to maintain a 0.2 μᴍ con centration, GPx in the presence of GSH, but neither GPx nor GSH alone, effectively inhib ited the hydroxylation of benzoate by peroxynitrite. Under these steady-state conditions peroxynitrite did not cause loss of ‘classical’ GPx activity. GPx, like selenomethionine, pro tected against protein 3-nitrotyrosine formation in human fibroblast lysates, shown in Western blots. The formation of nitrite rather than nitrate from peroxynitrite was enhanced by GPx , ebselen or selenomethionine. The selenoxides can be effectively reduced by glutathione, establishing a biological line of defense against peroxynitrite. The novel function of GPx as a peroxynitrite reductase may extend to other selenoproteins containing selenocysteine or selenomethionine. Recent work on organotellurium compounds revealed peroxynitrite reductase activity as well. Inhibition of dihydrorhodamine 123 oxidation correlated well with the GPx-like activity of a variety of diaryl tellurides.
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Crack, Peter J., Juliet M. Taylor, Judy B. de Haan, Ismail Kola, Paul Hertzog, and Rocco C. Iannello. "Glutathione Peroxidase-1 Contributes to the Neuroprotection Seen in the Superoxide Dismutase-1 Transgenic Mouse in Response to Ischemia/Reperfusion Injury." Journal of Cerebral Blood Flow & Metabolism 23, no. 1 (January 2003): 19–22. http://dx.doi.org/10.1097/01.wcb.0000035181.38851.71.
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The authors hypothesized that glutathione peroxidase-1 (Gpx-1) contributes to the neuroprotection seen in the superoxide dismutase-1 transgenic (Sod-1 tg) mouse. To investigate this hypothesis, they crossed the Gpx-1 -/- mouse with the Sod-1 tg and subjected the cross to a mouse model of ischemia/reperfusion. Two hours of focal cerebral ischemia followed by 24 hours of reperfusion was induced via intraluminal suture. The Sod-1 tg/Gpx-1 -/- cross exhibited no neuroprotection when infarct volume was measured; indeed, infarct volume increased in the Sod-1 tg/Gpx-1 -/- cross compared with the wild-type mouse. Our results suggest that Gpx-1 plays an important regulatory role in the protection of neural cells in response to ischemia/reperfusion injury.
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Perry, A. C. F., R. Jones, L. S. P. Niang, R. M. Jackson, and L. Hall. "Genetic evidence for an androgen-regulated epididymal secretory glutathione peroxidase whose transcript does not contain a selenocysteine codon." Biochemical Journal 285, no. 3 (August 1, 1992): 863–70. http://dx.doi.org/10.1042/bj2850863.
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Epididymal glutathione peroxidase (GPX) has been suggested as a major factor in combating loss of fertility of spermatozoa due to lipid peroxidation. We report here the isolation and sequence of putative GPX cDNAs from rat (Rattus rattus) and cynomolgus-monkey (Macaca fascicularis) epididymis, which exhibit marked sequence identity with known GPXs. In both species the cDNAs encode predicted preproteins containing 221 amino acid residues. Unlike other characterized GPX sequences, epididymal GPX mRNA does not contain a selenocysteine codon (UGA). However, sequence comparison and molecular-modelling studies suggest a high degree of structural conservation between epididymal and other GPXs. Transcripts corresponding to epididymal GPX are not detected in a variety of other tissues (liver, spleen, kidney and testis) and appear to be androgen-regulated in the epididymis.
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Duong, Chi, Huei Jiunn Seow, Steven Bozinovski, Peter J. Crack, Gary P. Anderson, and Ross Vlahos. "Glutathione peroxidase-1 protects against cigarette smoke-induced lung inflammation in mice." American Journal of Physiology-Lung Cellular and Molecular Physiology 299, no. 3 (September 2010): L425—L433. http://dx.doi.org/10.1152/ajplung.00038.2010.
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Reactive oxygen species (ROS) produced from cigarette smoke cause oxidative lung damage including protein denaturation, lipid peroxidation, and DNA damage. Glutathione peroxidase-1 (gpx-1) is a detoxifying enzyme that may protect lungs from such damage. The aim of this study was to determine whether gpx-1 protects the lung against oxidative stress-induced lung inflammation in vivo. Male wild-type (WT) or gpx-1−/− mice were exposed to cigarette smoke generated from nine cigarettes per day for 4 days to induce oxidative stress and lung inflammation. The effect of the gpx mimetic ebselen on cigarette smoke-induced lung inflammation was evaluated when given prophylactically and therapeutically, i.e., during established inflammation. Mice were killed, and the lungs were lavaged with PBS and then harvested for genomic and proteomic analysis. Gpx-1−/− mice exposed to cigarette smoke had enhanced BALF neutrophils, macrophages, proteolytic burden, whole lung IL-17A, and MIP1α mRNA compared with WT mice. The gpx mimetic ebselen (10 and 100 μM) inhibited cigarette smoke extract-induced oxidation of MH-S cells in vitro and inhibited cigarette smoke-induced increases in BALF macrophages, neutrophils, proteolytic burden, and macrophage and neutrophil chemotactic factor gene expression when administered prophylactically. In addition, ebselen inhibited established BALF inflammation when administered therapeutically. These data show that gpx-1 protects against cigarette smoke-induced lung inflammation, and agents that mimic the actions of gpx-1 may have therapeutic utility in inflammatory lung diseases where cigarette smoke plays a role.
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Harmon, Jamie S., Marika Bogdani, Susan D. Parazzoli, Sabrina S. M. Mak, Elizabeth A. Oseid, Marleen Berghmans, Renée C. LeBoeuf, and R. Paul Robertson. "β-Cell-Specific Overexpression of Glutathione Peroxidase Preserves Intranuclear MafA and Reverses Diabetes in db/db Mice." Endocrinology 150, no. 11 (October 9, 2009): 4855–62. http://dx.doi.org/10.1210/en.2009-0708.
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Chronic hyperglycemia causes oxidative stress, which contributes to damage in various tissues and cells, including pancreatic β-cells. The expression levels of antioxidant enzymes in the islet are low compared with other tissues, rendering the β-cell more susceptible to damage caused by hyperglycemia. The aim of this study was to investigate whether increasing levels of endogenous glutathione peroxidase-1 (GPx-1), specifically in β-cells, can protect them against the adverse effects of chronic hyperglycemia and assess mechanisms that may be involved. C57BLKS/J mice overexpressing the antioxidant enzyme GPx-1 only in pancreatic β-cells were generated. The biological effectiveness of the overexpressed GPx-1 transgene was documented when β-cells of transgenic mice were protected from streptozotocin. The transgene was then introgressed into the β-cells of db/db mice. Without use of hypoglycemic agents, hyperglycemia in db/db-GPx(+) mice was initially ameliorated compared with db/db-GPx(−) animals and then substantially reversed by 20 wk of age. β-Cell volume and insulin granulation and immunostaining were greater in db/db-GPx(+) animals compared with db/db-GPx(−) animals. Importantly, the loss of intranuclear musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) that was observed in nontransgenic db/db mice was prevented by GPx-1 overexpression, making this a likely mechanism for the improved glycemic control. These studies demonstrate that enhancement of intrinsic antioxidant defenses of the β-cell protects it against deterioration during hyperglycemia.
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Plestina-Borjan, Ivna, Damir Katusic, Maria Medvidovic-Grubisic, Daniela Supe-Domic, Kajo Bucan, Leida Tandara, and Veljko Rogosic. "Association of Age-Related Macular Degeneration with Erythrocyte Antioxidant Enzymes Activity and Serum Total Antioxidant Status." Oxidative Medicine and Cellular Longevity 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/804054.
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The aim was to estimate association of the oxidative stress with the occurrence of age-related macular degeneration (AMD). The activities of erythrocyte antioxidant enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) and additionally serum total antioxidant status (TAS) were used as indicators of the oxidative stress level. 57 AMD patients (32 early and 25 late AMD) and 50 healthy, age and gender matched controls were included. GPx activity (P<0.001) and serum TAS (P=0.015) were significantly lower in AMD patients. The difference was not significant for SOD or CAT activities. Significant interaction between GPx and SOD was detected (P=0.003). At high levels of SOD activity (over 75th percentile), one standard deviation decrease in GPx increases the odds for AMD for six times (OR = 6.22;P<0.001). ROC analysis revealed that combined values of GPx activity and TAS are significant determinants of AMD status. Accuracy, sensitivity, specificity, and positive and negative predictive values were 75%, 95%, 52%, 69%, and 90%, respectively. The study showed that low GPx activity and TAS are associated with AMD. SOD modulates the association of GPx and AMD. The results suggest that erythrocyte antioxidant enzymes activity and serum TAS could be promising markers for the prediction of AMD.
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Esworthy, R. Steven, Jeffrey R. Mann, Mindy Sam, and Fong-Fong Chu. "Low glutathione peroxidase activity in Gpx1knockout mice protects jejunum crypts from γ-irradiation damage." American Journal of Physiology-Gastrointestinal and Liver Physiology 279, no. 2 (August 1, 2000): G426—G436. http://dx.doi.org/10.1152/ajpgi.2000.279.2.g426.
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Gpx1 knockout (KO) mice had a higher number of regenerating crypts in the jejunum than did Gpx2-KO or wild-type mice analyzed 4 days after ≥10 Gy γ-irradiation. Without γ-irradiation, glutathione peroxidase (GPX) activity in the jejunal and ileal epithelium of Gpx1-KO mice was <10 and ∼35%, respectively, of that of the wild-type mice. Four days after exposure to 11 Gy, GPX activity in wild-type and Gpx1-KO ileum was doubled and tripled, respectively. However, jejunal GPX activity was not changed. Thus the lack of GPX activity in the jejunum is associated with better regeneration of crypt epithelium after radiation. Gpx2 gene expression was solely responsible for the increase in GPX activity in the ileum, since radiation did not alter GPX activity in Gpx2-KO mice. The intestinal Gpx2mRNA levels of Gpx1-KO and wild-type mice increased up to 14- and 7-fold after radiation, respectively. Although the Gpx1-KO jejunum had higher levels of PGE2 than the wild-type jejunum after exposure to 0 or 15 Gy, these differences were not statistically significant. Thus whether GPX inhibits PG biosynthesis in vivo remains to be established. We can conclude that the Gpx2 gene compensates for the lack of Gpx1gene expression in the ileal epithelium. This may have abolished the protective effect in Gpx1-KO mice against the radiation damage in the ileum.
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Vernet, Patrick, Nicole Rigaudiére, Norbert Ghyselinck, Jean Pierre Dufaure, and Joël R. Drevet. "In vitro expression of a mouse tissue specific glutathione-peroxidase-like protein lacking the selenocysteine can protect stably transfected mammalian cells against oxidative damage." Biochemistry and Cell Biology 74, no. 1 (January 1, 1996): 125–31. http://dx.doi.org/10.1139/o96-014.
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The complete sequence of the mouse epididymal protein (MEP24) was cloned. It contains a 663 bp open-reading frame that, after conceptual translation, shows extensive identity with proteins belonging to the glutathione peroxidase (GPX) family. However, a major difference between GPX5 (MEP24) and other known GPXs concerns a protein domain known to be critical for GPX function. To find out what could be the physiological function of such a protein in the mouse epididymis, we have used a mammalian expression system to overexpress the GPX5 protein. Cells constitutively expressing the GPX5 protein were generated and assayed for their ability to metabolize regular substrates of GPX enzymes. Data presented here show that the GPX5-expressing cells can metabolize hydrogen peroxide in a manner that is consistent with a peroxidase activity. However, the substrate preference of the GPX5-expressing cells and their apparent insensitivity to a regular inhibitor of GPX enzymes suggest that the GPX5 protein belongs to a particular class of GPX proteins. Involvement of this protein in the physiology of the mouse epididymis is discussed.Key words: glutathione peroxidase (GPX), mouse epididymis, MEP24, GPX5 cDNA, selenocysteine, GPX5 polyclonal antibody, spermatozoa, CHO-KI cells.
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Avissar, N., D. B. Ornt, Y. Yagil, S. Horowitz, R. H. Watkins, E. A. Kerl, K. Takahashi, I. S. Palmer, and H. J. Cohen. "Human kidney proximal tubules are the main source of plasma glutathione peroxidase." American Journal of Physiology-Cell Physiology 266, no. 2 (February 1, 1994): C367—C375. http://dx.doi.org/10.1152/ajpcell.1994.266.2.c367.
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The sites of synthesis of extracellular (E) glutathione peroxidase (GPX), a unique selenoglycoprotein present in plasma, are not known. To investigate the possibility that the kidney is the main source for the plasma GPX, we examined GPX activities and selenium concentrations in the plasma of patients with renal failure on dialysis and nephrectomized patients before and after kidney transplantation. Plasma GPX activities in these patients were 42, 22, and 180% of normal EGPX activity, respectively, whereas plasma Se levels were within the normal range. Twenty-four hours after nephrectomy of anesthetized rats, plasma GPX activity was 30.0 +/- 6.4% of the activity at zero time. Northern hybridization analysis of eight human tissues probed with EGPX and cellular glutathione peroxidase (CGPX) cDNA revealed that the ratio of EGPX to CGPX was highest in the kidney. cRNA in situ hybridization studies on kidney slices showed that only proximal tubular epithelial cells and parietal epithelial cells of Bowman's capsule contained EGPX transcripts. Caki-2, a proximal tubular renal carcinoma cell line, makes and actively secretes EGPX. Taken together, these results strongly suggest that kidney proximal tubular cells are the main source for GPX activity in the plasma.
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Benni, P., A. Y. Burdanov, V. V. Krushinsky, A. Bonfanti, G. Hébrard, J. M. Almenara, S. Dalal, et al. "Discovery of a young low-mass brown dwarf transiting a fast-rotating F-type star by the Galactic Plane eXoplanet (GPX) survey." Monthly Notices of the Royal Astronomical Society 505, no. 4 (May 31, 2021): 4956–67. http://dx.doi.org/10.1093/mnras/stab1567.
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ABSTRACT We announce the discovery of GPX-1 b, a transiting brown dwarf with a mass of 19.7 ± 1.6 MJup and a radius of 1.47 ± 0.10 RJup, the first substellar object discovered by the Galactic Plane eXoplanet (GPX) survey. The brown dwarf transits a moderately bright (V = 12.3 mag) fast-rotating F-type star with a projected rotational velocity $v\sin {\, i_*}=40\pm 10$ km s−1. We use the isochrone placement algorithm to characterize the host star, which has effective temperature 7000 ± 200 K, mass 1.68 ± 0.10 $\mathrm{\it M}_\odot$, radius 1.56 ± 0.10 $\mathrm{\it R}_\odot$, and approximate age $0.27_{-0.15}^{+0.09}$ Gyr. GPX-1 b has an orbital period of ∼1.75 d and a transit depth of 0.90 ± 0.03 per cent. We describe the GPX transit detection observations, subsequent photometric and speckle-interferometric follow-up observations, and SOPHIE spectroscopic measurements, which allowed us to establish the presence of a substellar object around the host star. GPX-1 was observed at 30-min integrations by TESS in Sector 18, but the data are affected by blending with a 3.4 mag brighter star 42 arcsec away. GPX-1 b is one of about two dozen transiting brown dwarfs known to date, with a mass close to the theoretical brown dwarf/gas giant planet mass transition boundary. Since GPX-1 is a moderately bright and fast-rotating star, it can be followed-up by the means of the Doppler tomography.
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Popovic-Dragonjic, Lidija, Maja Jovanovic, Tatjana Cvetkovic, Miodrag Vrbic, Biljana Kocic, Marina Djordjevic-Spasic, and Aleksandar Rankovic. "Erythrocyte antioxidative enzymes activities in patients with chronic hepatitis C treated with pegylated interferon alpha-2a and ribavirin." Vojnosanitetski pregled 74, no. 9 (2017): 840–48. http://dx.doi.org/10.2298/vsp150904277p.
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Background/Aim. In hepatitis C virus infection, oxidative stress and antioxidant imbalance are major triggers for the disease occurrence and its progression. The aim of the research was to determine the erythrocyte antioxidative enzymes activities, superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT), before and after therapy with pegylated interferon alpha-2a and ribavirin and to evaluate their clinical significance as potential diagnostic markers of sustained virological response (SVR). Methods. The study included 53 patients with chronic hepatitis C (CHC) and 56 healthy controls. SOD, GPx, CAT, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured in patients both before and after the treatment. Results. SOD, GPx and CAT activities prior to the treatment were significantly lower in CHC patients compared to the controls (p < 0.001), and they were significantly higher after the treatment (p < 0.001). A significant positive correlation existed between SOD, GPx, and CAT activites, before and after the treatment (p < 0.001) and with those of aminotransferases prior to the treatment (p < 0.001). After the treatment, only GPx activity showed significant negative correlation with that of aminotransferases (p < 0.001). Receiver operating characteristic curve analysis for SOD, GPx and CAT showed following values: area under the curve of 0.975, 0.988, and 0.817 respectively; sensitivity of 93.5%, 71.7%, 100% respectively and specificity of 100% for all, respectively. Forty six SVR achievers had significant increase of SOD, GPx and CAT activities (p < 0.001 for all), unlike 7 SVR non-achievers (p = 0.31, p = 0.717, p = 0.85, respectively). Conclusion. Oxidative stress is the initiator of onset and progression of CHC. The combined antiviral therapy leads to the restoration of antioxidant balance. GPx, SOD and CAT may be diagnostic markers of CHC treatment outcome.
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Santos, Cristina, Eduardo García-Fuentes, Belén Callejón-Leblic, Tamara García-Barrera, José Luis Gómez-Ariza, Margaret P. Rayman, and Inés Velasco. "Selenium, selenoproteins and selenometabolites in mothers and babies at the time of birth." British Journal of Nutrition 117, no. 9 (May 14, 2017): 1304–11. http://dx.doi.org/10.1017/s0007114517001155.
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AbstractThe deficiency of Se, an essential micronutrient, has been implicated in adverse pregnancy outcomes. Our study was designed to determine total serum Se, selenoproteins (extracellular glutathione peroxidase (GPx-3), selenoprotein P (SeP)), selenoalbumin (SeAlb) and selenometabolites in healthy women and their newborns at delivery. This cross-sectional study included eighty-three healthy mother–baby couples. Total Se and Se species concentrations were measured in maternal and umbilical cord sera by an in-series coupling of two-dimensional size-exclusion and affinity HPLC. Additional measurements of serum SeP concentration and of serum GPx-3 enzyme activity were carried out using ELISA. Total Se concentration was significantly higher in maternal serum than in cord serum (68·9 (sd 15·2) and 56·1 (sd 14·6) µg/l, respectively; P<0·01). There were significant correlations between selenoprotein and SeAlb concentrations in mothers and newborns, although they also showed significant differences in GPx-3 (11·2 (sd 3·7) v. 10·5 (sd 3·5) µg/l; P<0·01), SeP (42·5 (sd 9·5) v. 28·1 (sd 7·7) µg/l; P<0·01) and SeAlb (11·6 (sd 3·6) v. 14·1 (sd 4·3) µg/l; P<0·01) concentrations in maternal and cord sera, respectively. Serum GPx-3 activity and concentration were positively correlated in mothers (r 0·33; P=0·038) but not in newborns. GPx-3 activity in cord serum was significantly correlated with gestational age (r 0·44; P=0·009). SeAlb concentration was significantly higher in babies, whereas SeP and GPx-3 concentrations were significantly higher in mothers. The differences cannot be explained by simple diffusion; specific transfer mechanisms are probably involved. GPx-3 concentrations in mothers, at delivery, are related to maternal Se status, whereas the GPx-3 activity in cord serum depends on gestational age.
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Igarashi, Junsuke, Masashi Nishida, Shiro Hoshida, Nobushige Yamashita, Hiroaki Kosaka, Masatsugu Hori, Tsunehiko Kuzuya, and Michihiko Tada. "Inducible nitric oxide synthase augments injury elicited by oxidative stress in rat cardiac myocytes." American Journal of Physiology-Cell Physiology 274, no. 1 (January 1, 1998): C245—C252. http://dx.doi.org/10.1152/ajpcell.1998.274.1.c245.
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The effects of nitric oxide (NO) produced by cardiac inducible NO synthase (iNOS) on myocardial injury after oxidative stress were examined. Interleukin-1β induced cultured rat neonatal cardiac myocytes to express iNOS. After induction of iNOS,l-arginine enhanced NO production in a concentration-dependent manner. Glutathione peroxidase (GPX) activity in myocytes was attenuated by elevated iNOS activity and by an NO donor, S-nitroso- N-acetyl-penicillamine (SNAP). Although NO production by iNOS did not induce myocardial injury, NO augmented release of lactate dehydrogenase from myocyte cultures after addition of H2O2(0.1 mM, 1 h). Inhibition of iNOS with Nω-nitro-l-arginine methyl ester ameliorated the effects of NO-enhancing treatments on myocardial injury and GPX activity. SNAP augmented the myocardial injury induced by H2O2. Inhibition of GPX activity with antisense oligodeoxyribonucleotide for GPX mRNA increased myocardial injury by H2O2. Results suggest that the induction of cardiac iNOS promotes myocardial injury due to oxidative stress via inactivation of the intrinsic antioxidant enzyme, GPX.
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Arrasyid, Nurfida Khairina, Milahayati Daulay, and Mutiara Indah Sari. "Glutathione Peroxidase-1 Pro198Leu Variant in Tuberculosis-infected Type2 Diabetes Mellitus Patients at Pulmonary Polyclinic Medan." Open Access Macedonian Journal of Medical Sciences 9, A (June 27, 2021): 403–6. http://dx.doi.org/10.3889/oamjms.2021.6169.
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BACKGROUND: Glutathione peroxidase-1 (GPx-1) is an antioxidant that plays an important to the body protection system against oxidative stress. The GPx-1 polymorphism that has been identified in individual with several diseases. AIM: This study aimed to observe the distribution of GPx-1 Pro198Leu variant in tuberculosis (TB)-infected Type 2 diabetes mellitus (T2DM) patients at pulmonary polyclinic Medan. GPx-1 Pro198Leu polymorphism was genotyped in 40 T2DM patients that also infected by TB. MATERIALS AND METHODS: Analysis of GPx-1 Pro198Leu polymorphism was done using polymerase chain reaction (PCR) and restriction fragment length polymorphism. The PCR products were digested 4 h at 37°C with Apa1 restriction enzyme. The result of Apa1 enzyme digestion was visualized with 4% agarose. RESULTS: From 40 TB-infected T2DM patients, the frequency of genotypes CC,CT, and TT were, respectively, 82.5%, 17.5%, and 0%. The frequency of C allele was higher than T allele, i.e. 91.3% and 8.7%. CONCLUSION: It was concluded that in TB-infected T2DM patients at pulmonary polyclinic Medan, the GPx-1 Pro198Leu polymorphism has CC variant higher than CT, whereas the TT genotype was not found. The frequency of the C allele is higher than the T allele.
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Geraghty, Patrick, Nathalie Baumlin, Matthias A. Salathe, Robert F. Foronjy, and Jeanine M. D’Armiento. "Glutathione Peroxidase-1 Suppresses the Unfolded Protein Response upon Cigarette Smoke Exposure." Mediators of Inflammation 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/9461289.
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Oxidative stress provokes endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR) in the lungs of chronic obstructive pulmonary (COPD) subjects. The antioxidant, glutathione peroxidase-1 (GPx-1), counters oxidative stress induced by cigarette smoke exposure. Here, we investigate whether GPx-1 expression deters the UPR following exposure to cigarette smoke. Expression of ER stress markers was investigated in fully differentiated normal human bronchial epithelial (NHBE) cells isolated from nonsmoking, smoking, and COPD donors and redifferentiated at the air liquid interface. NHBE cells from COPD donors expressed heightened ATF4, XBP1, GRP78, GRP94, EDEM1, and CHOP compared to cells from nonsmoking donors. These changes coincided with reduced GPx-1 expression. Reintroduction of GPx-1 into NHBE cells isolated from COPD donors reduced the UPR. To determine whether the loss of GPx-1 expression has a direct impact on these ER stress markers during smoke exposure,Gpx-1−/−mice were exposed to cigarette smoke for 1 year. Loss ofGpx-1expression enhanced cigarette smoke-induced ER stress and apoptosis. Equally, induction of ER stress with tunicamycin enhanced antioxidant expression in mouse precision-cut lung slices. Smoke inhalation also exacerbated the UPR response during respiratory syncytial virus infection. Therefore, ER stress may be an antioxidant-related pathophysiological event in COPD.
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Xiao, Bi-huan, Meihui Shi, Hongqiang Chen, Shaoshan Cui, Yan Wu, Xing-Hua Gao, and Hong-Duo Chen. "Glutathione Peroxidase Level in Patients with Vitiligo: A Meta-Analysis." BioMed Research International 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/3029810.
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Abnormality of glutathione peroxidase (GPx) is involved in the etiology and pathogenesis of vitiligo. However, the results were controversial.Aim. The purpose of this meta-analysis is to compare the levels of GPx between vitiligo patients and healthy controls.Methods.Relevant published articles were searched according to eligibility criteria. A meta-analysis was conducted to pool estimates of the standardized mean difference (SMD) with 95% confidence interval (CI).Results.Twenty-three studies with a total of 1076 vitiligo patients and 770 healthy controls were included. The pooled meta-analysis showed that patients with vitiligo had equivalent levels of GPx with the healthy controls (SMD = −0.47, 95% CI: −1.03 to 0.08, andp=0.095). Further subgroup analysis showed that the GPx levels of Asian patients or segmental vitiligo patients were, respectively, lower than those of healthy controls (Asian: SMD = −0.47, 95% CI: −1.08 to 0.14, andp=0.001; segmental: SMD = −3.59, 95% CI: −6.38 to −0.80, andp=0.012). Furthermore, the GPx levels in serum/plasma were significantly decreased in either stable or active vitiligo patients, comparing to healthy controls (stable: SMD = −2.01, 95% CI: −3.52 to −0.49, andp=0.009; active: SMD = −2.34, 95% CI: −4.07 to −0.61, andp=0.008).Conclusion. This meta-analysis showed a significant association between low GPx level and vitiligo.
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Sinaga, Fajar Apollo, and Nora Susanti. "THE INFLUENCE OF RED FRUIT (PANDANUS CONOIDEUS LAM.) OIL ON GLUTATHIONE PEROXIDASE LEVEL AT MAXIMUM PHYSICAL ACTIVITY." Asian Journal of Pharmaceutical and Clinical Research 11, no. 13 (April 26, 2018): 104. http://dx.doi.org/10.22159/ajpcr.2018.v11s1.26579.
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Objectives: This study aims to see the effect of red fruit oil (RFO) on glutathione peroxidase (GPx) level at maximum physical activity.Methods: This study is an experimental research using the design of randomized control group pretest-posttest. This study was using 24 male mice divided into four groups, the control group was given aquadest, the treatment groups P1, P2, and P3 were given the RFO orally of 0.15 ml/kg BW, 0.3 ml/kg BW, and 0.6 ml/kg BW, respectively, for a month. The level of GPx was checked for all groups at the beginning of study and after the maximum physical activity. The obtained data were then tested statistically using t-test and ANOVA.Results: The result shows the RFO supplementation during exercise increased the GPx level in P1, P2, and P3 groups with p<0.05, and the higher RFO dosage resulted in higher GPx level at p<0.05.Conclusion: The conclusion of this study is the RFO could increase the level of GPx at maximum physical activity.
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Esworthy, R. Steven, Richard Aranda, Martín G. Martín, James H. Doroshow, Scott W. Binder, and Fong-Fong Chu. "Mice with combined disruption ofGpx1andGpx2genes have colitis." American Journal of Physiology-Gastrointestinal and Liver Physiology 281, no. 3 (September 1, 2001): G848—G855. http://dx.doi.org/10.1152/ajpgi.2001.281.3.g848.
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Glutathione peroxidase (GPX)-1 and gastrointestinal (GI) epithelium-specific GPX (GPX-GI), encoded by Gpx1 and Gpx2, provide most GPX activity in GI epithelium. Although homozygous mice deficient in either the Gpx1 or Gpx2 gene appeared to be normal under standard housing conditions, homozygous mice deficient in both genes, double-knockout (KO) mice, had symptoms and pathology consistent with inflammatory bowel disease. These symptoms included a high incidence of perianal ulceration, growth retardation that started around weaning, and hypothermia that resembled that observed in calorie-restricted mice, even though the double-KO mice in our study were allowed to eat ad libitum. The growth retardation and hypothermia were components of cachexia, which is fatal in a high percentage of mice. Histological examination revealed that the double-KO mice had a high incidence of mucosal inflammation in the ileum and colon but not in the jejunum. Elevated levels of myeloperoxidase activity and lipid hydroperoxides were also detected in colon mucosa of these homozygous double-KO mice. These results suggest that GPX is essential for the prevention of the inflammatory response in intestinal mucosa.
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Indriawati, Ratna, and Anatyo Nizar. "Antioxidant Potential of Kersen Leaves (Muntingia Calabura L.) Leaves to Increase Endogenous Glutathione Peroxidase (GPx) Enzymes in Diabetic Rats." E3S Web of Conferences 202 (2020): 12004. http://dx.doi.org/10.1051/e3sconf/202020212004.
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The prevalence of diabetes mellitus (DM) is increasing. DM can cause an imbalance between protective antioxidants and increased production of free radicals. One such antioxidant is the endogenous enzyme glutathione peroxidase (GPx). Kersen (Muntingia calabura L.) contains flavonoids which show antioxidant activity. The purpose of this study was to examine the potential antioxidant of Kersen Leaves (Muntingia Calabura L.) leaves to GPx Enzymes in Diabetic Rats. This research is included in an experimental study with a post-test design only with control category design. The subjects of this study were 36 male rats. The measure of GDP levels using the GOD-PAP enzymatic method, while GPx uses the UV method. Data were analyzed using paired-t-test and OneWay ANOVA test. Statistical test results with paired t test showed significant differences in GDP levels before and after treatment (p = 0.0001). In the OneWay ANOVA test there was a average different GPx levels in each category (p = 0.0001). The most effective steeping increases the GPx level is a dose of 750 mg / 200 gr BW.
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Keller, Jeffrey N., Feng F. Huang, Hong Zhu, Jin Yu, Ye-Shih Ho, and Mark S. Kindy. "Oxidative Stress-Associated Impairment of Proteasome Activity during Ischemia–Reperfusion Injury." Journal of Cerebral Blood Flow & Metabolism 20, no. 10 (October 2000): 1467–73. http://dx.doi.org/10.1097/00004647-200010000-00008.
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Numerous studies indicate a role for oxidative stress in the neuronal degeneration and cell death that occur during ischemia–reperfusion injury. Recent data suggest that inhibition of the proteasome may be a means by which oxidative stress mediates neuronal cell death. In the current study, the authors demonstrate that there is a time-dependent decrease in proteasome activity, which is not associated with decreased expression of proteasome subunits, after cerebral ischemia–reperfusion injury. To determine the role of oxidative stress in mediating proteasome inhibition, ischemia–reperfusion studies were conducted in mice that either overexpressed the antioxidant enzyme glutathione peroxidase [GPX 1(+)], or were devoid of glutathione peroxidase activity (GPX −/−). After ischemia–reperfusion, GPX 1(+) mice displayed decreased infarct size, attenuated neurologic impairment, and reduced levels of proteasome inhibition compared with either GPX −/− or wild type mice. In addition, GPX 1(+) mice displayed lower levels of 4-hydroxynonenal-modified proteasome subunits after ischemia–reperfusion injury. Together, these data indicate that proteasome inhibition occurs during cerebral ischemia–reperfusion injury and is mediated, at least in part, by oxidative stress.
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Zedan, Hatem, Amira Ali Abdel-Motaleb, Nahed Mahmoud Ali Kassem, Heba Ahmed Abdel Hafeez, and Mahmoud Rezk Abdelwhahed Hussein. "Low Glutathione Peroxidase Activity Levels in Patients with Vitiligo." Journal of Cutaneous Medicine and Surgery 19, no. 2 (March 2015): 144–48. http://dx.doi.org/10.2310/7750.2014.14076.
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Background Vitiligo is an idiopathic skin disease characterized by white areas on the skin due to loss of the functional melanocytes, with possible involvement of oxidative stress. Glutathione peroxidase (GPx) is an antioxidant enzyme that protects cells against oxidative damage. Aim To examine serum GPx levels in patients with vitiligo and to relate the findings to the clinical features. Patients and Methods The study group included 60 patients with vitiligo and 30 matching healthy controls. GPx activity was evaluated using enzyme-linked immunosorbent assay. Results We found a significant decrease in serum GPx activity level in the patients with vitiligo compared to the healthy controls (0.29 ± 0.14 versus 0.47 ± 0.13, p < .001). The levels were significantly low in skin phenotypes III and IV ( p < .001). Higher levels were also observed with increasing age (≥ 14 years), prolonged disease duration (≥ 3 years), and generalized and extensive vitiligo (<50%). However, these variations were statistically insignificant. Conclusions Low levels of serum GPx activity, indicative of a disturbed oxidant-antioxidant system, may contribute to the development of vitiligo.
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Hasansulama, Wijana, Teti Madiadipoera, Sunarjati Sunarjati, and Herry Garna. "Glutathione Peroxide and Glutathione to Disulfide Glutathione Ratio in Presbycusis: a Case-control Study." Medical Archives 76, no. 3 (2022): 209. http://dx.doi.org/10.5455/medarh.2022.76.209-214.
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Background: Presbycusis is a gradual hearing loss caused by the ageing process. This is a chronic condition that affects the elderly population, and sensorineural progressive bilateral symmetry occurs with predominantly high-frequency hearing loss. The ability to discriminate speech decreases; hence, most of the affected patients have conversation problems, especially in noisy environments.This situation is a serious problem among elderly individuals. Social isolation, depression, and paranoia can be related to presbycusis. Objective: The aim of this study was to investigate GPx and the GSH:GSSG ratio as risk factors for presbycusis. Methods: A case-control study was conducted to determine the role of GPx activity with the GSH:GSSG ratio as a presbycusis risk factor in 60 subjects aged 55 to 75 years old during the period of August 2012 - April 2014. All of the subjects passed an ENT examination, pure tone audiometry, and tympanometry. The activity of GPx was measured with the Paglia and Valentine method, and the GSH:GSSG ratio was measured by the calorimetric method. Results: The activity of GPx and the GSH:GSSG ratio were significantly different between the groups (p<0.05), and the odds ratio for high GPx with a low GSH:GSSG ratio was 135 (CI 95%: 5.17–20,028.88). Conclusion: High GPx activity with a low GSH:GSSG ratio is a risk factor for presbycusis.
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Steyn, Mia, Karima Zitouni, Frank J. Kelly, Paul Cook, and Kenneth A. Earle. "Sex Differences in Glutathione Peroxidase Activity and Central Obesity in Patients with Type 2 Diabetes at High Risk of Cardio-Renal Disease." Antioxidants 8, no. 12 (December 7, 2019): 629. http://dx.doi.org/10.3390/antiox8120629.
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Women with type 2 diabetes (T2DM) have an increased susceptibility of developing cardio-renal disease compared to men, the reasons and the mechanisms of this vulnerability are unclear. Since oxidative stress plays a key role in the development of cardio-renal disease, we investigated the relationship between sex, plasma antioxidants status (glutathione peroxidase (GPx-3 activity), vitamin E and selenium), and adiposity in patients with T2DM at high risk of cardio-renal disease. Women compared to men had higher GPx-3 activity (p = 0.02), bio-impedance (p ≤ 0.0001), and an increase in waist circumference in relation to recommended cut off-points (p = 0.0001). Waist circumference and BMI were negatively correlated with GPx-3 activity (p ≤ 0.05 and p ≤ 0.01, respectively) and selenium concentration (p ≤ 0.01 and p ≤ 0.02, respectively). In multiple regression analysis, waist circumference and sex were independent predictors of GPx-3 activity (p ≤ 0.05 and p ≤ 0.05, respectively). The data suggest that increased central fat deposits are associated with reduced plasma antioxidants which could contribute to the future risk of cardio-renal disease. The increased GPx-3 activity in women could represent a preserved response to the disproportionate increase in visceral fat. Future studies should be aimed at evaluating if the modulation of GPx-3 activity reduces cardio-renal risk in men and women with T2DM.
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Gaber, Ahmed, Masahiro Tamoi, Toru Takeda, Yoshihisa Nakano, and Shigeru Shigeoka. "NADPH-dependent glutathione peroxidase-like proteins (Gpx-1, Gpx-2) reduce unsaturated fatty acid hydroperoxides inSynechocystisPCC 6803." FEBS Letters 499, no. 1-2 (June 14, 2001): 32–36. http://dx.doi.org/10.1016/s0014-5793(01)02517-0.
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Shi, Cheng, Qiugang Huang, Ruirui Zhang, Xingtang Liang, Feng Wang, Zijie Liu, Min Liu, Huayu Hu, and Yanzhen Yin. "Preparation and catalytic behavior of antioxidant cassava starch with selenium active sites and hydrophobic microenvironments." RSC Advances 11, no. 63 (2021): 39758–67. http://dx.doi.org/10.1039/d1ra06832f.
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The preparation of antioxidant starch with the activity of glutathione peroxidase (GPx) for scavenging free radicals can not only enrich the types of modified starch but also alternate native GPx to overcome its drawbacks.
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Elfaky, Mahmoud A., Alaa Sirwi, Sameh H. Ismail, Heba H. Awad, and Sameh S. Gad. "Hepatoprotective Effect of Silver Nanoparticles at Two Different Particle Sizes: Comparative Study with and without Silymarin." Current Issues in Molecular Biology 44, no. 7 (June 30, 2022): 2923–38. http://dx.doi.org/10.3390/cimb44070202.
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Silver nanoparticles have been used for numerous therapeutic purposes because of their increased biodegradability and bioavailability, yet their toxicity remains questionable as they are known to interact easily with biological systems because of their small size. This study aimed to investigate and compare the effect of silver nanoparticles’ particle size in terms of their potential hazard, as well as their potential protective effect in an LPS-induced hepatotoxicity model. Liver slices were obtained from Sprague Dawley adult male rats, and the thickness of the slices was optimized to 150 μm. Under regulated physiological circumstances, freshly cut liver slices were divided into six different groups; GP1: normal, GP2: LPS (control), GP3: LPS + AgNpL (positive control), GP4: LPS + silymarin (standard treatment), GP5: LPS + AgNpS + silymarin (treatment I), GP6: LPS + AgNpL + silymarin (treatment II). After 24 h of incubation, the plates were gently removed, and the supernatant and tissue homogenate were all collected and then subjected to the following biochemical parameters: Cox2, NO, IL-6, and TNF-α. The LPS elicited marked hepatic tissue injury manifested by elevated cytokines and proinflammatory markers. Both small silver nanoparticles and large silver nanoparticles efficiently attenuated LPS hepatotoxicity, mainly via preserving the cytokines’ level and diminishing the inflammatory pathways. In conclusion, large silver nanoparticles exhibited effective hepatoprotective capabilities over small silver nanoparticles.
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Kaur, Rajinder, Sandeep Kaur, Neelima R. Kumar, and Kusum Harjai. "Honey bee collected pollen and beebread of Zea mays: determination of bioactive constituents and health benefits." Research Journal of Biotechnology 18, no. 3 (February 15, 2023): 64–69. http://dx.doi.org/10.25303/1803rjbt64069.
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Bee products are known since ancient times for their nutritional value and beneficial effects. The present study was carried out to evaluate the phytochemical composition and therapeutic potential of bee pollen and beebread. Broth dilution method was used to observe the in vitro antibacterial activity. For in vivo antioxidant activities, BALB/c mice were divided into six groups; Gp1 was given normal saline only, Gp2 was injected intraperitoneally with Salmonella enterica serovar Typhimurium at 2×104 CFU/ml, Gp3 was administrated orally with bee collected pollen of Zea mays (250mg/kg bw) only, Gp4 was treated with the bee collected pollen of Z. mays (250mg/kg bw) in Salmonella infected mice, Gp5 was administrated orally with beebread of Z. mays (250mg/kg bw) only and Gp6 was treated with the beebread of Z. mays (250mg/kg bw) in Salmonella infected mice. The results obtained in the study suggested that various bioactive constituents were present in bee pollen and beebread and these phytochemical constituents were responsible for the antibacterial and antioxidant efficacy of these studied bee products. Beebread was found to possess high activity as compared to bee pollen reflecting its high polphenolic composition. Hence, it could be inferred that bee pollen could be seen as a potential source for designing a drug against S. typhimurium.
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Sheldon, R. Ann, Raha Sadjadi, Matthew Lam, Russell Fitzgerald, and Donna M. Ferriero. "Alteration in Downstream Hypoxia Gene Signaling in Neonatal Glutathione Peroxidase Overexpressing Mouse Brain after Hypoxia-Ischemia." Developmental Neuroscience 37, no. 4-5 (2015): 398–406. http://dx.doi.org/10.1159/000375369.
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We have previously shown that glutathione peroxidase (GPx) overexpressing mice (hGPx-tg) have reduced brain injury after neonatal hypoxia-ischemia (HI) as a consequence of reduced hydrogen peroxide accumulation. However, this protection is reversed with hypoxia preconditioning, raising the question of the roles of the genes regulated by hypoxia-inducible factor-1α (HIF-1α) and their transcription products, such as erythropoietin (EPO), in both the initial protection and subsequent reversal of protection. hGPx-tg and their wild-type (WT) littermates underwent the Vannucci procedure of HI brain injury at postnatal day 9 - left carotid artery ligation followed by exposure to 10% oxygen for 50 min. Brain cortices and hippocampi were subsequently collected 0.5, 4 and 24 h later for the determination of protein expression by Western blot for GPx, HIF-1α, HIF-2α, EPO, EPO receptor, ERK1/2, phospho-ERK1/2, spectrin 145/150 (as a marker of calpain-specific necrotic cell death), and spectrin 120 (as a marker of apoptotic cell death mediated via caspase-3). As expected, the GPx overexpressing mouse cortex had approximately 3 times the GPx expression as WT naïve. Also, GPx expression remained higher in the GPx overexpressing brain than WT at all time points after HI (0.5, 4, 24 h). HIF-1α was not significantly changed in hGPx-tg as a consequence of HI but decreased in the WT cortex 4 h after HI. HIF-2α decreased in the WT hippocampus after HI. EPO was higher in the GPx overexpressing cortex and hippocampus 30 min after HI compared to WT, but the EPO receptor was unchanged by HI. ERK1/2 phosphorylation increased in the hippocampus at 4 h after HI and in the cortex at 24 h after HI in both WT and hGPx-tg. Spectrin 145/150 was increased in the WT cortex at 4 and 24 h after HI, and spectrin 120 increased 24 h after HI, perhaps reflecting greater injury in the WT brain, especially at 24 h when brain injury is more evident. The effect of GPx overexpression does not appear to upregulate the HIF pathway, yet EPO was upregulated, perhaps via ERK. This might explain, in part, why cell death takes a necrotic or apoptotic path. This may also be an explanation for why the GPx overexpressing brain cannot be preconditioned. This information may prove valuable in the development of therapies for neonatal HI brain injury.