Reactive Oxygen Species

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Claude Gagnon - One of the best experts on this subject based on the ideXlab platform.

  • production of Reactive Oxygen Species by spermatozoa undergoing cooling freezing and thawing
    Molecular Reproduction and Development, 2001
    Co-Authors: Suvro Chatterjee, Claude Gagnon
    Abstract:

    In the present study, we provide evidence for the production of Reactive Oxygen Species (ROS) during cryopreservation of bovine spermatozoa. Cooling and thawing of spermatozoa cause an increase in the generation of superoxide radicals. Although nitric oxide production remains unaltered during sperm cooling from 22–4°C, a sudden burst of nitric oxide radicals is observed during thawing. Increase in lipid peroxidation levels have been observed in frozen/thawed spermatozoa and appears to be associated with a reduction in sperm membrane fluidity as detected by spin labeling studies. The data presented provide strong evidence that Oxygen free radicals are produced during freezing and thawing of bovine spermatozoa and suggest that these Reactive Oxygen Species may be a cause for the decrease in sperm function following cryopreservation. Mol. Reprod. Dev. 59: 451–458, 2001. © 2001 Wiley-Liss, Inc.

  • production of Reactive Oxygen Species by spermatozoa undergoing cooling freezing and thawing
    Molecular Reproduction and Development, 2001
    Co-Authors: Suvro Chatterjee, Claude Gagnon
    Abstract:

    In the present study, we provide evidence for the production of Reactive Oxygen Species (ROS) during cryopreservation of bovine spermatozoa. Cooling and thawing of spermatozoa cause an increase in the generation of superoxide radicals. Although nitric oxide production remains unaltered during sperm cooling from 22-4 degrees C, a sudden burst of nitric oxide radicals is observed during thawing. Increase in lipid peroxidation levels have been observed in frozen/thawed spermatozoa and appears to be associated with a reduction in sperm membrane fluidity as detected by spin labeling studies. The data presented provide strong evidence that Oxygen free radicals are produced during freezing and thawing of bovine spermatozoa and suggest that these Reactive Oxygen Species may be a cause for the decrease in sperm function following cryopreservation. Mol. Reprod. Dev. 59: 451-458, 2001.

  • formation of Reactive Oxygen Species in spermatozoa of infertile patients
    Fertility and Sterility, 1992
    Co-Authors: Akira Iwasaki, Claude Gagnon
    Abstract:

    Objective To determine the incidence of Reactive Oxygen Species formation in semen of a population of patients consulting for infertility. Design The incidence of Reactive Oxygen Species formation in whole semen and in washed spermatozoa was studied. The values obtained were correlated with semen parameters. The effect of the type of sperm washing on Reactive Oxygen Species formation was also investigated. Setting Semen samples from patients consulting for infertility and control subjects were obtained by masturbation after 3 days of sexual abstinence. Reactive Oxygen Species formation was measured in whole semen, sperm suspension washed by Percoll gradients, or repeated centrifugations. Sperm motility parameters were measured by computer-aided sperm analysis. Patients, Participants Fertile control men and an unselected population of patients consulting for infertility. Interventions None. Main Outcome Measure Reactive Oxygen Species formation by fresh semen specimen or washed spermatozoa was measured in a computer-driven LKB 1251 Luminometer (LKB-Wallac, Turku, Finland). Results Reactive Oxygen Species formation was detected in 40% of the semen with spermatozoa from infertile patients, whereas none was found in 6 azoospermic men and 10 control men. The level of Reactive Oxygen Species formation was inversely correlated to the semen volume, the percentage of motile spermatozoa, and sperm linearity both in semen and in Percoll-washed spermatozoa. Washing by repeated centrifugation-resuspension increased 20- to 50-fold sperm Reactive Oxygen Species formation. This enhancement was caused by the centrifugation itself and by the removal of seminal plasma. Both morphologically normal and abnormal spermatozoa produced Reactive Oxygen Species. Conclusion The data suggest that Reactive Oxygen Species formation by spermatozoa may be a significant cause for male infertility.

Rama Rao Malla - One of the best experts on this subject based on the ideXlab platform.

  • Reactive Oxygen Species a key constituent in cancer survival
    Biomarker Insights, 2018
    Co-Authors: Seema Kumari, Anil Kumar Badana, Murali Mohan G, Gugalavath Shailender, Rama Rao Malla
    Abstract:

    Background:Cancer is one of the major heterogeneous disease with high morbidity and mortality with poor prognosis. Elevated levels of Reactive Oxygen Species (ROS), alteration in redox balance, and...

  • Reactive Oxygen Species: A Key Constituent in Cancer Survival
    SAGE Publishing, 2018
    Co-Authors: Seema Kumari, Anil Kumar Badana, Murali Mohan G, Shailender G, Rama Rao Malla
    Abstract:

    Background: Cancer is one of the major heterogeneous disease with high morbidity and mortality with poor prognosis. Elevated levels of Reactive Oxygen Species (ROS), alteration in redox balance, and deregulated redox signaling are common hallmarks of cancer progression and resistance to treatment. Mitochondria contribute mainly in the generation of ROS during oxidative phosphorylation. Elevated levels of ROS have been detected in cancers cells due to high metabolic activity, cellular signaling, peroxisomal activity, mitochondrial dysfunction, activation of oncogene, and increased enzymatic activity of oxidases, cycloOxygenases, lipOxygenases, and thymidine phosphorylases. Cells maintain intracellular homeostasis by developing an immense antioxidant system including catalase, superoxide dismutase, and glutathione peroxidase. Besides these enzymes exist an important antioxidant glutathione and transcription factor Nrf2 which contribute in balancing oxidative stress. Reactive Oxygen Species–mediated signaling pathways activate pro-oncogenic signaling which eases in cancer progression, angiogenesis, and survival. Concomitantly, to maintain ROS homeostasis and evade cancer cell death, an increased level of antioxidant capacity is associated with cancer cells. Conclusions: This review focuses the role of ROS in cancer survival pathways and importance of targeting the ROS signal involved in cancer development, which is a new strategy in cancer treatment

Shen Kou Tsai - One of the best experts on this subject based on the ideXlab platform.

  • the anti inflammatory effect of honokiol on neutrophils mechanisms in the inhibition of Reactive Oxygen Species production
    European Journal of Pharmacology, 2003
    Co-Authors: Kuotong Liou, Shen Kou Tsai, Yuhchiang Shen, Chiehfu Chen, Chengming Tsao
    Abstract:

    Reactive Oxygen Species produced by neutrophils contribute to the pathogenesis of focal cerebral ischemia/reperfusion injury and signal the inflammatory response. We have previously shown that honokiol, an active principle extracted from Magnolia officinalis, has a protective effect against focal cerebral ischemia/reperfusion injury in rats that paralleled a reduction in Reactive Oxygen Species production by neutrophils. To elucidate the underlying mechanism(s) of the antioxidative effect of honokiol, peripheral neutrophils isolated from rats were activated with phorbol-12-myristate-13-acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) in the presence or absence of honokiol. In this study, we found that honokiol inhibited PMA- or fMLP-induced Reactive Oxygen Species production by neutrophils by three distinct mechanisms: (1) honokiol diminished the activity of assembled-NADPH oxidase, a major Reactive Oxygen Species producing enzyme in neutrophils by 40% without interfering with its protein kinase C (PKC)-dependent assembly; (2) two other important enzymes for Reactive Oxygen Species generation in neutrophils, i.e., myeloperoxidase and cycloOxygenase, were also inhibited by honokiol by 20% and 70%, respectively; and (3) honokiol enhanced glutathione (GSH) peroxidase activity by 30%, an enzyme that triggers the metabolism of hydrogen peroxide (H2O2). These data suggested that honokiol, acting as a potent Reactive Oxygen Species inhibitor/scavenger, could achieve its focal cerebral ischemia/reperfusion injury protective effect by modulating enzyme systems related to Reactive Oxygen Species production or metabolism, including NADPH oxidase, myeloperoxidase, cycloOxygenase, and GSH peroxidase in neutrophils.

Peter Storz - One of the best experts on this subject based on the ideXlab platform.

  • Reactive Oxygen Species in cancer
    Free Radical Research, 2010
    Co-Authors: Geou Yarh Liou, Peter Storz
    Abstract:

    Elevated rates of Reactive Oxygen Species (ROS) have been detected in almost all cancers, where they promote many aspects of tumour development and progression. However, tumour cells also express increased levels of antioxidant proteins to detoxify from ROS, suggesting that a delicate balance of intracellular ROS levels is required for cancer cell function. Further, the radical generated, the location of its generation, as well as the local concentration is important for the cellular functions of ROS in cancer. A challenge for novel therapeutic strategies will be the fine tuning of intracellular ROS signalling to effectively deprive cells from ROS-induced tumour promoting events, towards tipping the balance to ROS-induced apoptotic signalling. Alternatively, therapeutic antioxidants may prevent early events in tumour development, where ROS are important. However, to effectively target cancer cells specific ROS-sensing signalling pathways that mediate the diverse stress-regulated cellular functions need to be identified. This review discusses the generation of ROS within tumour cells, their detoxification, their cellular effects, as well as the major signalling cascades they utilize, but also provides an outlook on their modulation in therapeutics.

  • Reactive Oxygen Species in cancer
    Free Radical Research, 2010
    Co-Authors: Geou Yarh Liou, Peter Storz
    Abstract:

    AbstractElevated rates of Reactive Oxygen Species (ROS) have been detected in almost all cancers, where they promote many aspects of tumour development and progression. However, tumour cells also express increased levels of antioxidant proteins to detoxify from ROS, suggesting that a delicate balance of intracellular ROS levels is required for cancer cell function. Further, the radical generated, the location of its generation, as well as the local concentration is important for the cellular functions of ROS in cancer. A challenge for novel therapeutic strategies will be the fine tuning of intracellular ROS signalling to effectively deprive cells from ROS-induced tumour promoting events, towards tipping the balance to ROS-induced apoptotic signalling. Alternatively, therapeutic antioxidants may prevent early events in tumour development, where ROS are important. However, to effectively target cancer cells specific ROS-sensing signalling pathways that mediate the diverse stress-regulated cellular functions...

  • Reactive Oxygen Species in tumor progression
    Frontiers in Bioscience, 2005
    Co-Authors: Peter Storz
    Abstract:

    The generation of Reactive Oxygen radicals in mammalian cells profoundly affects numerous critical cellular functions, and the absence of efficient cellular detoxification mechanisms which remove these radicals can result in several human diseases. Growing evidence suggests that Reactive Oxygen Species (ROS) within cells act as second messengers in intracellular signaling cascades which induce and maintain the oncogenic phenotype of cancer cells. ROS are tumorigenic by virtue of their ability to increase cell proliferation, survival, cellular migration, and also by inducing DNA damage leading to genetic lesions that initiate tumorigenicity and sustain subsequent tumor progression. However, it is also known that ROS can induce cellular senescence and cell death and can therefore function as anti-tumorigenic agents. Therefore, the mechanisms by which cells respond to Reactive Oxygen Species depends on the molecular background of cell and tissues, the location of ROS production and the concentration of individual ROS Species. Carcinoma cells produce ROS at elevated rates in vitro, and in vivo many tumors appear persistent to oxidative stress. Thus, the finding that a diet rich in antioxidants or the elimination of ROS by antioxidant compounds prevents the development of certain cancers provided the setting for subsequent investigation of the tumorigenic actions of Reactive Oxygen Species. This review outlines the current knowledge on the various roles of ROS in tumor development and progression.

Francesca Levischaffer - One of the best experts on this subject based on the ideXlab platform.

  • role of Reactive Oxygen Species ros in apoptosis induction
    Apoptosis, 2000
    Co-Authors: Hansuwe Simon, Abdulla Hajyehia, Francesca Levischaffer
    Abstract:

    Reactive Oxygen Species (ROS) and mitochondria play an important role in apoptosis induction under both physiologic and pathologic conditions. Interestingly, mitochondria are both source and target of ROS. Cytochrome c release from mitochondria, that triggers caspase activation, appears to be largely mediated by direct or indirect ROS action. On the other hand, ROS have also anti-apoptotic effects. This review focuses on the role of ROS in the regulation of apoptosis, especially in inflammatory cells.