Accumulation of lung tissue oxidized glutathione (GSSG) as a marker of oxidant induced lung injury.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
J E Repine
Publications and source records attributed to J E Repine.
HEPES may stimulate cultured endothelial cells to make growth-retarding oxygen metabolites.
Zwitterion buffers are often used to modulate the pH of cell culture medium but their effect on cultured cells is controversial. We found that addition of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) caused superoxide dismutase (SOD) inhibitable increases in nitroblue tetrazolium dye reduction and SOD and catalase inhibitable decreases in the growth of cultured bovine pulmonary artery endothelial cells. The findings suggest that HEPES stimulates endothelial cells to make toxic oxygen metabolites that contribute to decreased cell growth.
Animals↗
Hydrogen peroxide causes dimethylthiourea consumption while hydroxyl radical causes dimethyl sulfoxide consumption in vitro.
Addition of increasing concentrations of hydrogen peroxide (H2O2) caused progressive decreases in dimethylthiourea (DMTU) concentrations which were inhibitable by simultaneous addition of catalase, but not the superoxide anion (O2-.) scavenger, superoxide dismutase (SOD), or hydroxyl radical (.OH) scavengers, such as mannitol, sodium benzoate or dimethyl sulfoxide (DMSO). In parallel, addition of increasing concentrations of H2O2 with FE++/EDTA (but not H2O2 alone) caused decreases in DMSO concentrations which were inhibitable by simultaneous addition of .OH scavengers but not SOD or catalase. Addition of DMTU, but not DMSO, also decreased H2O2 concentrations in vitro. The results indicate the relative scavenging specificities of DMTU and DMSO for H2O2 and .OH, respectively. The findings also suggest that measurement of DMTU or DMSO consumption could help assess the contribution of O2 metabolites in biological systems.
Chromatography, Gas↗
Dimethylthiourea consumption reflects H2O2 concentrations and severity of acute lung injury.
Even though dimethylthiourea (DMTU) effectively scavenges O2 metabolites in vitro, it is often unclear if scavenging of O2 metabolites is the mechanism by which DMTU decreases tissue injury in biological models. Since DMTU not only scavenges O2 metabolites but is also consumed in a dose-response manner following reaction with hydrogen peroxide (H2O2) in vitro, we wondered whether DMTU would also be consumed by O2 metabolites in biological systems and if DMTU consumption would then reflect O2 metabolite concentrations and O2 metabolite-mediated injury. Our results supported this possibility. We found that selected nonprotecting concentrations of DMTU were consumed in isolated rat lungs perfused with H2O2 and that the amounts of DMTU consumed reflected both the added amounts of H2O2 and the corresponding degrees of H2O2-induced acute edematous injury. DMTU consumption was relatively specific for reaction with H2O2 occurring in isolated lungs that were injured by H2O2 but not lungs injured by elastase, oleic acid, histamine, or a venous pressure challenge. Our results suggest that measurement of DMTU consumption may be useful for assessing the presence and toxicity of O2 metabolites and the specificity of the protective effects of DMTU in biological systems.
Animals↗
Effect of superoxide dismutase encapsulated in liposomes or conjugated with polyethylene glycol on neutrophil bactericidal activity in vitro and bacterial clearance in vivo.
Encapsulation in liposomes (LIP) or conjugation with polyethylene glycol (PEG) are methods being used to increase circulating half-life periods and/or improve delivery of antioxidant enzymes that could decrease lung injury induced by O2 metabolites. We found that pretreatment with LIP, with or without the antioxidant enzyme, superoxide dismutase (SOD), decreased killing of Staphylococcus aureus 502A by neutrophils in vitro and clearance of intravenously injected S. aureus in rabbits in vivo. In contrast, pretreatment with PEG (with or without SOD) had no effect on neutrophil bactericidal activity in vitro or bacterial clearance in vivo. Our results suggest that conjugation with PEG may be a better way than encapsulation in liposomes for delivering antioxidant enzymes, especially if one is concerned about preserving host-defense mechanisms.
Animals↗
Bacillus Calmette-Guérin-stimulated neutrophils release chemotaxins for monocytes in rabbit pleural spaces and in vitro.
Neutrophils are often seen first at sites of granulomatous inflammation but their contribution to monocyte recruitment and granuloma formation is unknown. We tested the hypothesis that neutrophils release chemotaxins which attract monocytes. We found that rapid accumulations of fluid and influxes of neutrophils followed by monocytes occurred in bacillus Calmette--Guérin (BCG)-sensitized rabbits given BCG intrapleurally but did not occur in nitrogen mustard-treated (neutropenic) BCG-sensitized rabbits given BCG intrapleurally--unless the rabbits were also given intrapleural injections of neutrophils. We also found monocyte chemotaxins in pleural spaces of control and neutrophil-reconstituted neutropenic but not in neutropenic rabbits given BCG intrapleurally. Moreover, pleural fluid monocyte chemotaxins had molecular weights (12,000-15,000 and 1,000) that were similar to molecular weights of monocyte chemotaxins present in supernatants from mixtures of neutrophils and BCG in vitro. In addition, intrapleural injection of neutrophils and BCG or supernatants from in vitro mixtures of neutrophils and BCG (but not neutrophils or BCG alone) increased the numbers of monocytes and 3H cell pellet activity in pleural fluids from untreated neutropenic rabbits or neutropenic rabbits previously injected intravenously with 3[H]methyl thymidine-labeled monocytes. Furthermore, fewer BCG were recovered from pleural fluids of BCG-sensitized control compared to neutropenic rabbits given BCG, and at autopsy 10 d after instillation of BCG, control but not neutropenic rabbits had well-defined granulomas without adhesions on their pleural surfaces. Our results suggest that BCG stimulates neutrophils to release chemotaxins that recruit monocytes, and that these responses might contribute to granuloma formation in tuberculous pleurisy.
Animals↗
Pulmonary host defense mechanisms.
Explore the source record for details and available documents.
Bacterial Infections↗
Pulmonary antioxidant defense mechanisms.
Intrinsic enzymatic and non-enzymatic pulmonary antioxidant defense mechanisms undoubtedly protect the lung against oxidant-mediated environmental stresses and diseases. In addition, new ways of augmenting pulmonary antioxidant defenses are being developed which can be used to bolster disease-overwhelmed intrinsic lung defense mechanisms. Improved understanding of antioxidant defense mechanisms will increase our knowledge of the causes and suggest rational approaches for treating oxidant-induced lung injury.
Acetylcysteine↗
Macrophage effector function in pulmonary oxygen toxicity: hyperoxia damages and stimulates alveolar macrophages to make and release chemotaxins for polymorphonuclear leukocytes.
Macrophages synthesize many secretory products in vitro but the stimuli for their production and their pathophysiologic significance in vivo are largely unknown. In the present investigation, we found that hyperoxia damaged rabbit alveolar macrophages (AM) in vitro as manifested by decreased cell numbers, increased lactate dehydrogenase (LDH) release, and the development of ultrastructural abnormalities that resembled those seen in AM in situ or lavaged from lungs of rabbits exposed to hyperoxia in vivo. Hyperoxia also stimulated cultured rabbit AM to release chemotaxins for polymorphonuclear leukocytes (PMN) that were similar in molecular weight to chemotaxins obtained from lung lavages of rabbits exposed to hyperoxia in vivo. Our results suggest that alveolar macrophage secretory products may play a physiologically relevant role in recruitment of PMN to the lungs in pulmonary oxygen toxicity.
Animals↗
Simultaneous measurement of adherence and chemiluminescence by polymorphonuclear leukocytes.
Oxygen radical release from adhering polymorphonuclear leukocytes (PMN) has been implicated as an important feature of many vascular diseases. We developed a technique by which adherence and production of O2 radicals by PMN can be measured simultaneously. The technique combines the conventional nylon fiber assay for measuring adherence of PMN with concurrent scintillation counter measurement of chemiluminescence (CL) to assess O2 radical production by PMN. We found that adherence of PMN to nylon fiber is associated with increases in CL. Moreover, increases in CL appear to be dependent on generation of O2 radicals from PMN since they are not seen with PMN from a patient with chronic granulomatous disease (CGD) or in the presence of O2 radical scavengers, superoxide dismutase, or catalase. Furthermore, agents which increase the adherence of PMN to nylon fiber are associated with increases in CL. Use of this approach may facilitate simultaneous evaluation of adherence and O2 radical generation by PMN.
Cell Adhesion↗
Measurement of oxidizing radicals by polymorphonuclear leukocytes.
O2 radicals are important in health and disease. The most commonly used ways of identifying O2 radicals in PMN are described above. Several shortcomings exist in these methods reflecting the unusual, complex nature of O2 radical biochemistry. Some general principles include (1) O2 radicals are very short-lived, reacting with many other compounds and each other quickly. (2) There are no highly specific assays for O2 radicals. (3) Highly specific scavengers of O2 radicals also do not exist. (4) No methods have been found to detect and quantitate O2 radicals in vivo. (5) Solubility and membrane permeability of various scavengers and/or test reagents may affect the measurement of O2 radicals in PMN and other biological systems. In general, the best approach to measurement of O2 radicals involves using the best assay available and showing that the reaction is inhibited by scavengers in proportion to their reactivity with the specific O2 radical being assayed.
Chromatography, Gas↗
Cyclical abnormalities in the bactericidal function, superoxide production, and lysozyme activity of neutrophils obtained from a healthy woman during menstruation: reversal by pretreatment with aspirin.
Neutrophils obtained from most of 13 healthy young women during menstruation and those obtained from the same women on nonmenstrual days killed comparable numbers of Staphylococcus aureus strain 502A, produced comparable amounts of superoxide anion, and had comparable lysozyme levels. In contrast, neutrophils obtained from a few women during menstruation exhibited decreased function. In particular, neutrophils from one healthy woman developed transient menstrual period-related abnormalities in bactericidal function, superoxide anion production, and lysozyme activity and release; these abnormalities occurred during each of three menstrual periods tested but not during three menstrual periods following the ingestion of aspirin for 14 days. The results suggest that menstrual period-related dysfunction of neutrophils may occur in some healthy women, sometimes rendering them more susceptible to menstrual period-related infections.
Adult↗
Hydroxyl radical scavengers produce similar decreases in the chemiluminescence responses and bactericidal activities of neutrophils.
The addition of hydroxyl radical (.OH) scavengers caused similar decreases in the chemiluminescence responses and killing of Staphylococcus aureus 502A by human neutrophils in vitro.
Catalase↗
Staphylococcus aureus and human platelets cause pulmonary hypertension and thromboxane generation in isolated saline-perfused rabbit lungs.
The potential contributions of bacterial-platelet interactions to the development of acute edematous lung injury, such as that seen in the adult respiratory distress syndrome (ARDS), remains unknown. We found that the addition of Staphylococcus aureus, 502A to isolated rabbit lungs perfused with saline, and human platelets rapidly decreased the number of circulating platelets, increased pulmonary artery perfusion pressures, and generated thromboxane B2, the stable derivative of thromboxane A2. In contrast, increases in perfusion pressures or thromboxane levels did not occur when platelets treated with acetylsalicylic acid (ASA) were used, even though ASA-treated platelets disappeared from the perfusates. The results suggest that activation of platelets by bacteria may account for thrombocytopenia, platelet microemboli, and/or contribute to increases in pulmonary artery pressures seen in some patients with ARDS.
Animals↗
Intact human erythrocytes prevent hydrogen peroxide-mediated damage to isolated perfused rat lungs and cultured bovine pulmonary artery endothelial cells.
Addition of untreated or glutaraldehyde-fixed human erythrocytes decreased hydrogen peroxide (H2O2)-mediated acute edematous injury in isolated rat lungs, H2O2-induced damage to cultured bovine pulmonary artery endothelial cells, and H2O2-dependent oxidation of reduced cytochrome C in vitro. The results suggest that intact erythrocytes can scavenge H2O2, and as a result, protect the lung and possibly other tissues from damage.
Animals↗
Oxygen metabolites stimulate thromboxane production and vasoconstriction in isolated saline-perfused rabbit lungs.
Generation of reactive oxygen metabolites, thromboxane increases, and vasoconstriction have been implicated in the pathogenesis of acute edematous lung injury, such as that seen in patients with the Adult Respiratory Distress Syndrome (ARDS), but their interactions are unknown. We hypothesized that reactive O2 products would stimulate arachidonic acid metabolism in lungs and that vasoactive products of arachidonate, such as the potent vasoconstrictor thromboxane A2, might then mediate O2-metabolite-induced pulmonary vasoconstriction. We found that O2 metabolites generated by injection of purine plus xanthine oxidase caused increases in mean pulmonary artery perfusion pressures (27 +/- 4 mmHg) in isolated perfused lungs. In addition, purine plus xanthine oxidase also caused 30-fold increases in perfusate levels of thromboxane B2 (the stable metabolite of thromboxane A2) compared with only twofold increases in 6-keto-PGF1a (the stable metabolite of prostacyclin). Moreover, prior addition of catalase inhibited both vasoconstriction and the thromboxane B2 production seen in isolated lungs following injection of purine plus xanthine oxidase. Similarly, pretreatment with cyclooxygenase inhibitors, either aspirin or indomethacin, also completely blocked thromboxane generation and markedly attenuated pressor responses usually seen after purine plus xanthine oxidase (increase in mean pulmonary artery perfusion pressures, 4.4 +/- 1.5 mmHg). Furthermore, imidazole, a thromboxane synthetase inhibitor, also decreased O2-metabolite-induced thromboxane generation and vasoconstriction. These results suggested that thromboxane generation might participate in O2-metabolite-induced vasoconstriction. However, since a significant correlation between thromboxane levels and the degree of vasoconstriction could not be demonstrated, and since addition of superoxide dismutase reduced thromboxane generation but did not affect the intensity of vasoconstriction, it is possible that thromboxane is not the only vasoactive mediator in this model. We conclude that exposing lungs to O2 metabolites results in thromboxane generation and that thromboxane is a major mediator of oxidant-induced vasoconstriction.
Animals↗
Hyperoxia stimulates alveolar macrophages to produce and release a factor which increases neutrophil adherence.
Hyperoxia stimulates alveolar macrophages (AM) to make and release a factor which increases neutrophil adherence to nylon fiber. Production of the neutrophil adherence-stimulating factory by AM exposed to hyperoxia is maximal after AM have been exposed to hyperoxia for 72 h and requires protein synthesis by intact AM. The adherence factor is heat-labile and by column chromatography elutes in a molecular-weight range of approximately 8000-18,000 daltons. The lungs of animals exposed to hyperoxia and contribute to neutrophil-mediated lung injury from hyperoxia.
Animals↗
Dimethyl sulfoxide inhibits phagocyte influx into infected pleural spaces and phagocyte locomotion in vitro.
Influx of polymorphonuclear leukocytes (PMNs) and monocytes (MNs) into pleural spaces was decreased in dimethyl sulfoxide (DMSO)-treated rabbits infected intrapleurally with Staphylococcus aureus. In addition, pleural fluids contained S. aureus longer and marked pleural thickening with fibrosis occurred in DMSO-treated rabbits. DMSO also inhibited stimulated locomotion of PMN and MN in vitro, suggesting that the aforementioned responses in vivo may have occurred because of DMSO-mediated inhibition of the locomotion of PMN and MN.
Animals↗