von Ana Catarina Ribeiro Carrão
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| [1.] Arc/Fragment 021 11 - Diskussion Zuletzt bearbeitet: 2014-02-26 20:44:01 Graf Isolan | Arc, Fragment, Gesichtet, Quinn and Gauss 2004, SMWFragment, Schutzlevel sysop, Verschleierung |
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| Untersuchte Arbeit: Seite: 21, Zeilen: 11-21 |
Quelle: Quinn and Gauss 2004 Seite(n): 760, Zeilen: r.col: 16ff |
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| Neutrophil granulocytes (a.k.a., polymorphonuclear leukocytes) are normally found circulating in the bloodstream (half-life of ≅7 h) and migrating through tissues (2–3 days), devoting their short lifetime to surveillance55. During an infection, the neutrophil lifespan is increased, and large numbers of neutrophils are rapidly recruited to the site(s) of infection where they function to destroy invading pathogens. In this manner, neutrophils serve as one of the body’s first lines of defence against infection. These cells use an extraordinary array of oxygen-dependent and oxygen-independent microbicidal weapons to destroy and remove infectious agents56. Oxygen-dependent mechanisms involve the production of ROS, which can be microbicidal57, and oxygen-independent mechanisms include most other neutrophil functions, such as chemotaxis, phagocytosis, degranulation, and release of lytic enzymes and bactericidal peptides56.
55. Steinfeld JL. Principles of Hematology. Cancer Res. 1967;27:208-a-. 56. Witko-Sarsat V, Rieu P, Descamps-Latscha B, Lesavre P, Halbwachs-Mecarelli L. Neutrophils: Molecules, Functions and Pathophysiological Aspects. Lab Invest. 2000;80:617-653. 57. Roos D, Bruggena Rv, Meischl C. Oxidative killing of microbes by neutrophils. Microbes and Infection. 2003;5:1307-1315. |
Neutrophils (a.k.a., polymorphonuclear leukocytes) are normally found circulating in the bloodstream (circulating half-life of ~7 h) and migrating through tissues (2–3 days) and devote their short lifetime to surveillance [3]. However, during an infection, the neutrophil lifespan is increased, and large numbers of neutrophils are rapidly recruited to the site(s) of infection where they function to destroy invading pathogens. In this capacity, neutrophils serve as one of the body’s first lines of defense against infection. These cells use an extraordinary array of oxygen-dependent and oxygen-independent microbicidal weapons to destroy and remove infectious agents [4]. Oxygen-dependent mechanisms involve the production of reactive oxygen species (ROS), which can be microbicidal [5], and oxygen-independent mechanisms include most other neutrophil functions, such as chemotaxis, phagocytosis, degranulation, and release of lytic enzymes and bactericidal peptides (reviewed in ref. [4]).
3. Haen, P. J. (1995) Principles of Hematology, Dubuque, IA, Wm. C. Brown. 4. Witko-Sarsat, V., Rieu, P., Descamps-Latscha, B., Lesavre, P., Halbwachs-Mecarelli, L. (2000) Neutrophils: molecules, functions and pathophysiological aspects. Lab. Invest. 80, 617–653. 5. Roos, D., Van Bruggen, R., Meischl, C. (2003) Oxidative killing of microbes by neutrophils. Microbes Infect. 5, 1307–1315. |
The source is not given here. |
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| [2.] Arc/Fragment 021 22 - Diskussion Zuletzt bearbeitet: 2014-02-26 22:17:25 Schumann | Arc, BauernOpfer, Bedard Krause 2007, Fragment, Gesichtet, SMWFragment, Schutzlevel sysop |
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| Untersuchte Arbeit: Seite: 21, Zeilen: 22-30 |
Quelle: Bedard Krause 2007 Seite(n): 246, Zeilen: l.col: 9ff |
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| ROS are oxygen-derived small molecules, including oxygen radicals [superoxide (O2•–), hydroxyl (•OH), peroxyl (RO2•), and alkoxyl (RO•) radicals] and certain non-radicals that are either oxidizing agents and/or are easily converted into radicals, such as hypochlorous acid (HOCl), ozone (O3), singlet oxygen (1O2), and hydrogen peroxide (H2O2). ROS generation is generally a cascade of reactions that starts with the production of superoxide. Superoxide rapidly dismutates to hydrogen peroxide either spontaneously (at low pH) or catalyzed by superoxide dismutase (SOD). Other elements in the cascade of ROS generation include the reaction of superoxide with nitric oxide to form peroxynitrite (ONOO–), the peroxidase-catalyzed formation of hypochlorous acid [(HOCl) from hydrogen peroxide, and the iron-catalyzed Fenton reaction leading to the generation of hydroxyl radical58.]
Thannickal VJ, Fanburg BL. Reactive oxygen species in cell signaling. Am J Physiol Lung Cell Mol Physiol. 2000;279:L1005-1028. |
Reactive oxygen species (ROS) are oxygen-derived small molecules, including oxygen radicals [superoxide (O2•–), hydroxyl (•OH), peroxyl (RO2•), and alkoxyl (RO•)] and certain nonradicals that are either oxidizing agents and/or are easily converted into radicals, such as hypochlorous acid (HOCl), ozone (O3), singlet oxygen (1O2), and hydrogen peroxide (H2O2). Nitrogen-containing oxidants, such as nitric oxide, are called reactive nitrogen species (RNS). ROS generation is generally a cascade of reactions that starts with the production of superoxide. Superoxide rapidly dismutates to hydrogen peroxide either spontaneously, particularly at low pH or catalyzed by superoxide dismutase. Other elements in the cascade of ROS generation include the reaction of superoxide with nitric oxide to form peroxynitrite, the peroxidase-catalyzed formation of hypochlorous acid from hydrogen peroxide, and the iron-catalyzed Fenton reaction leading to the generation of hydroxyl radical (468, 874).
468. Klebanoff SJ. Oxygen metabolism and the toxic properties of phagocytes. Ann Intern Med 93: 480–489, 1980. 874. Thannickal VJ, Fanburg BL. Reactive oxygen species in cell signaling. Am J Physiol Lung Cell Mol Physiol 279: L1005–L1028, 2000. |
The source is mentioned further down on the next page, without any indication that everything including references to the literature are taken from it. To be continued on the next page: Arc/Fragment_022_01 |
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Letzte Bearbeitung dieser Seite: durch Benutzer:Graf Isolan, Zeitstempel: 20140226204537