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  • 1980-1984  (5)
Publikationsart
Verlag/Herausgeber
Erscheinungszeitraum
Jahr
  • 1
    ISSN: 1420-908X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The interaction of myeloperoxidase (MPO) with H2O2 and Cl− provides a potent antimicrobial/cytotoxic system for polymorphonuclear leukocytes (PMNs). MPO-related cytotoxicity may be associated with the formation of toxic oxidant MPO intermediates, HOCl, or both. MPO itself is able to oxidize drugs and cellular components. Non-steroidal anti-inflammatory drugs (NSAIDs) able to act as antioxidant free radical scavengers have recently been shown to inhibit luminol-enhanced chemiluminescence (CL) which results from the MPO−H2O2−Cl− reaction. CL is a measure of the activity of this reaction. At that time it was not clear whether the source of CL which these NSAIDs affected was HOCl or components of the initial MPO−H2O2−Cl− reaction. A NSAID antioxidant mechanism could affect MPO oxidant intermediates and HOCl. This study compares the effects of antioxidant NSAIDs, methylprednisone and free radical scavengers against MPO-based and NaOCl-based luminol-enhanced CL. Most NSAIDs which affected both MPO and NaOCl-CL appeared to share similar mechanisms, suggesting that MPO oxidant internediates and HOCl are susceptible to NSAID effects. However, most NSAIDs were more effective against MPO-CL. The effect of these NSAIDs against MPO-CL followed the profile of NSAIDs effective in previous studies against PMN-CL. One exception to this was methylprednisone, which has no effect on PMN or MPO-CL, yet inhibited NaOCl-CL. This and other data suggest that MPO and not HOCl-related reactions are a major source of PMN-CL. Less effective NSAIDs affected NaOCl-CL better than MPO-CL. While both HOCl and MPO oxidant intermediates may be affected by NSAIDs, it appears that MPO oxidant intermediates or MPO itself are the primary target for NSAID antioxidant free radical scavenging mechanisms. These antioxidant effects impair the major killing system of the PMN and may be NSAIDs' primary anti-inflammatory mechanism. Although our data suggests the production of superoxide anion and hydroxyl radical from the MPO−H2O2−Cl− reaction, the actual presence or involvement of these free radical species is not confirmed herein.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Inflammation research 13 (1983), S. 59-62 
    ISSN: 1420-908X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The ability of general anesthetics to depress immune function may lead to increased risk of infection in surgical patients. Recently, halothane, an inhalational anesthetic, was shown to inhibit neutrophil bactericidal mechanisms, the center of which is the reaction of myeloperoxidase with H2O2 and Cl−. This study demonstrates the ability of ketamine, an injectable anesthetic, to interfere with the cytotoxic neutrophil myeloperoxidase-H2O2−Cl− reaction, as tested using a luminol-enhanced chemiluminescence assay. Ketamine, due to its phenolic structure, may scavenge the cytotoxic free radical intermediates of this reaction, as shown previously for non-steroidal anti-inflammatory drugs. This paper, then, identifies a potential mechanism whereby ketamine anesthesia could suppress neutrophil defense mechanisms, thus rendering the surgical patient more susceptible to infection.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    ISSN: 1420-908X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The action of non-steroidal anti-inflammatory drugs (NSAIDS) has been ascribed to their ability to block the reaction of arachidonate with cyclooxygenase/peroxidase, thus inhibiting the cellular production of inflammation mediators such as prostaglandins and leukotrienes. However, this and other polymorphonuclear leukocyte (PMN) peroxidases such as myeloperoxidase (MPO) would still be capable of producing destructive oxidants which contribute to inflammation. Sulindac sulfide (Clinoril® sulfide) has recently been shown to scavenge oxidant products of prostaglandin cyclooxygenase/peroxidase and MPO. The MPO−H2O2−Cl− reaction is a potent antimicrobial/cytotoxic system which produces HOCl, a strong oxidant. MPO itself has the ability to oxidize drugs and cellular components, and may be the main oxidant in PMN defenses. An antioxidant/free radical scavenger action of NSAIDs against the MPO system could be a primary mechanism of their anti-inflammatory effects. Other antioxidant/free radical scavengers have anti-inflammatory effects. MPO activity has previously been quantified using chemiluminescence (CL). In this study, NSAIDs from various classes were tested for their ability to inhibit luminol-enhanced CL from MPO. The most potent NSAIDs against MPO-CL were BW755C, phenylbutazone, indomethacin and sulindac sulfide. Salicylates and arylacetic acid derivatives, such as naproxen, also decreased MPO-CL. These drugs are also effective against CL from PMNs, of which MPO may be a main source. This effect of NSAIDs on MPO suggests that NSAIDs may impair the killing mechanism of the PMN, preventing cell destruction and release of inflammation mediators. PMN MPO appears to be a target for the antioxidant/free radical scavenging effects of NSAIDs.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    ISSN: 1573-2576
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We prepared FMoxLP by oxidation of FMLP and evaluated its ability to trigger a variety of granulocyte responses. FMoxLP was found to depolarize granulocyte membranes; increase granulocyte oxygen consumption, superoxide production, and hydrogen peroxide production; compete with FMLP for binding to granulocytes; and stimulate granulocyte chemotaxis. Against all of these granulocyte functions, FMoxLP was considerably less potent than the parent FMLP. When luminol-dependent-granulocyte chemiluminescence (CL) was studied, FMoxLP was observed to be a more potent stimulus of this response than FMLP. This increased CL activity of FMoxLP may be related to nonoxidative burst mechanisms. Our results indicate that FMoxLP retains a significant amount of the biological activity of FMLP (albeit in general less potent). The biological importance of the observed activities of FMoxLP must await further investigation.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    ISSN: 1573-2576
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A system is described to evaluate for nonsteroidal antiinflammatory drugs by means of luminol-dependent human-granulocyte chemiluminescence (CL) is described. The CL is produced using either opsonized zymosan (yeast cells) or the soluble chemotactic peptide f-Met-Leu-Phe as the perturbant of the granulocyte membrane. Using either system, the following drug effects 2×10−5 M were noted: only sulindac sulfide, and not sulindac sulfone or sulindac, displayed marked inhibition of chemiluminescence, following the in vivo data regarding inflammatory effects. The 5-OH indomethacin metabolite was likewise inactive as an inhibitor of CL mirroring in vivo effects. MK(+)410, MK(−)830 and MK835 all showed approximately 50% inhibition of CL, displaying deviation from in vivo data. MK(+)830 markedly stimulated CL, 4–6 times the control (without drug), which is clearly different from its enantiomer, MK(−)830. The reasons for this behavior are unclear. However, receptor binding studies with [3H]FMLP were accomplished in the presence and absence of the various drugs at 2×105 M that were effective inhibitors of chemiluminescence (CL). Indomethacin, MK(−)830 and MK(+)410 had equivalent percent control binding and percent control CL. Sulindac sulfide and MK(+)835 both had higher percent control binding than percent control CL, with MK(+)835 displaying apparent increased numbers of available receptors relative to control. MK(+)830, which produces large increases in CL, produced a minor effect on percent control binding. A direct relationship between binding and CL does not exist with each drug. Chemiluminescence is dependent on ion movement and oxidative metabolism and is a secondary event to agonist-receptor occupation.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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