[Interstitial lung involvement in a 41-year-old woman with pneumothorax history].
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Adult↗
Biomedical subjects
J J Zulueta
Publications and source records attributed to J J Zulueta.
Upregulation of xanthine oxidase by lipopolysaccharide, interleukin-1, and hypoxia. Role in acute lung injury.
LPS and selected cytokines upregulate xanthine dehydrogenase/xanthine oxidase (XDH/XO) in cellular systems. However, the effect of these factors on in vivo XDH/XO expression, and their contribution to lung injury, are poorly understood. Rats were exposed to normoxia or hypoxia for 24 h after treatment with LPS (1 mg/kg) and IL-1beta (100 microg/kg) or sterile saline. Lungs were then harvested for measurement of XDH/XO enzymatic activity and gene expression, and pulmonary edema was assessed by measurement of the wet/dry lung weight ratio (W/D). Although treatment with LPS + IL-1beta or hypoxia independently produced a 2-fold elevation (p < 0. 05 versus exposure to normoxia and treatment with saline) in lung XDH/XO activity and mRNA, the combination of LPS + IL-1beta and hypoxia caused a 4- and 3.5-fold increase in these values, respectively. XDH/XO protein expression was increased 2-fold by hypoxia alone and 1.3-fold by treatment with LPS + IL-1beta alone or combination treatment. Compared with normoxic lungs, W/D was significantly increased by exposure to hypoxia, LPS + IL-1beta, or combination treatment. This increase was prevented by treatment of the animals with tungsten, which abrogated lung XDH/XO activity. In conclusion, LPS, IL-1beta, and hypoxia significantly upregulate lung XDH/XO expression in vivo. The present data support a role for this enzyme in the pathogenesis of acute lung injury.
Animals↗
Intracellular generation of reactive oxygen species in endothelial cells exposed to anoxia-reoxygenation.
Reactive oxygen species (ROS) play an important role in the pathogenesis of ischemia-reperfusion injury. Extracellular H2O2 generation from bovine pulmonary artery endothelial cells (EC) is known to increase in response to anoxia-reoxygenation (A-R). To determine potential sources of intracellular ROS formation in EC in response to A-R, a fluorometric assay based on the oxidation of 2',7'-dichlorofluorescin was used. Intracellular ROS production declined 40% during 6 h of anoxia (P < 0.05). After A-R, the rates of intracellular ROS formation increased to 148 +/- 9% (P < 0.001) that of normoxic EC (100 +/- 3%). In EC exposed to A-R, allopurinol and NG-methyl-L-arginine (L-NMMA), inhibitors of xanthine oxidase (XO) and nitric oxide synthase (NOS), respectively, reduced intracellular ROS formation by 25 +/- 1% (P < 0.001) and 36 +/- 4% (P < 0.01). Furthermore, at low doses (i.e., 20 microM), deferoxamine and diethylenetriaminepentaacetic acid (DTPA) significantly inhibited intracellular ROS formation. However, at 100 microM, only deferoxamine caused further reduction in DCF fluorescence. In summary, EC respond to A-R by generating increased amounts of XO- and NOS-derived intracellular ROS. The inhibition, to a similar extent, caused by allopurinol and L-NMMA, as well as the effect of deferoxamine and DTPA suggest that the ROS detected is peroxynitrite. Based on these findings and previous work, we conclude that EC generate ROS in response to A-R from at least two different sources: a plasma membrane-bound NADPH oxidase-like enzyme that releases H2O2 extracellularly and XO, which generates intracellular O2-, which in turn may react with nitric oxide to form peroxynitrite.
Animals↗
Regulation of intracellular xanthine oxidase by endothelial-derived nitric oxide.
We have previously shown that nitric oxide (NO) donors, such as nitrosoglutathione, inhibit endothelial cell (EC) xanthine dehydrogenase (XD)/xanthine oxidase (XO) activity. The purpose of this study was to assess whether endothelial-derived NO plays any role in the regulation of intracellular XD/XO. We exposed rat pulmonary microvascular EC to L-arginine (precursor of NO) or inhibitors of nitric oxide synthase (NOS), i.e., NG-nitro-L-arginine methyl esther (L-NAME) and NG-nitro-L-arginine, in conditions of normoxia, hypoxia, and hypoxia followed by reoxygenation. Hypoxia alone caused a 1.9- and a 6.6-fold increase in XO and a 5-fold increase in XO + XD activities after 24 and 48 h of exposure, respectively. The combination of hypoxia and L-NAME (300 microM) treatment amounted at 48 h to a 10- and 7.5-fold increase in XO and XO + XD activities, respectively, compared with normoxic untreated cells. L-NAME also prevented the decline in XD/XO activity that occurred in untreated EC after hypoxia-reoxygenation. On the other hand, treatment with L-arginine caused a dose-dependent decrease in XD/XO activity in hypoxic EC compared with cells provided with L-arginine-free medium. In separate experiments, we assessed the role of L-arginine supplementation on the in vivo regulation of lung XD/XO by exposing male adult Sprague-Dawley rats for a period of 5 days to a hypoxic hypobaric atmosphere (0.5 atm). Exposure to hypoxia produced a significant increase in lung tissue XO activity and an increase in the ratio of XO to XD. L-Arginine supplementation in the drinking water prevented the increase in lung XO and the XO-to-XD ratio in hypoxic rats and caused a significant decrease in XO and XD in rats exposed to normoxia. In conclusion, this study suggests that endogenous NO has a significant role in the regulation of XD/XO both in vitro and in vivo. By inhibiting XD/XO activity, NO may have a modulating effect in conditions of hypoxia and hypoxia-reoxygenation, where this enzyme is thought to be important.
Animals↗
Lung cancer in patients with bullous disease.
There have been sporadic reports in the literature of an association between bullous disease of the lung and lung cancer; however, we believe that this clinical association is not well recognized. We present six cases in which bullous disease of the lung and lung cancer coexisted, and review the available literature on the topic. Five of the patients were males, the mean age of presentation was 42 yr (range: 32 to 62 yr), and all of the patients were smokers. Histologically the tumors in all six patients were non-small-cell carcinomas. The significantly younger age of these patients with lung cancer and bullous disease as compared with those reported in the literature with lung cancer but without bullous disease suggests that the association between these two processes is more than just coincidental. The utility of plain radiography and computerized tomography (CT) of the chest in screening patients with bullous disease for lung cancer is discussed.
Adult↗
Effect of nitric oxide and cell redox status on the regulation of endothelial cell xanthine dehydrogenase.
We have previously reported that endothelial cell (EC) xanthine dehydrogenase/xanthine oxidase (XD/XO) activity correlates inversely with the O2 tension to which the cells are exposed. Whether this effect is related to the production of reactive O2 species is unclear. We exposed bovine pulmonary artery EC to various conditions that altered the redox status of the cells: 1) hypoxia (3% O2) and normoxia (20% O2); 2) menadione (MEN), known to generate O2 radicals; 3) catalase (CAT) and reduced glutathione (GSH), which detoxify H2O2; and 4) various NO-generating systems. Changes in intracellular XO and XO + XD activities were correlated with rates of extracellular H2O2 release from the same cells. Conditions that decreased extracellular H2O2 release (hypoxia, CAT, and GSH) produced significant and parallel increases in intracellular XO and XO + XD activities in a time-dependent fashion. MEN treatment increased extracellular release of H2O2 and subsequently reduced intracellular XO and XO + XD activities. NO-generating agents did not change extracellular release of H2O2 but significantly reduced XO and XO + XD activities. The latter effect was prevented by reduced hemoglobin. Scavengers of hydroxyl radicals reversed the inhibition of XO and XO + XD activities produced by MEN but not that produced by NO. While NO significantly inhibited XD/XO activity from rat epididymal fat pad, it did not affect XD/XO mRNA expression in these cells. We conclude that intracellular XD/XO activity is sensitive to changes in oxidant-generating and protective systems. Inhibition of XD/XO activity by NO may be mediated through direct binding of NO to the enzyme iron-sulfur moiety or to its sulfhydryl groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Release of hydrogen peroxide in response to hypoxia-reoxygenation: role of an NAD(P)H oxidase-like enzyme in endothelial cell plasma membrane.
The dynamics and mechanisms of extracellular release of hydrogen peroxide (H2O2) from bovine pulmonary artery endothelial cells (EC) subjected to anoxia, hypoxia, and hypoxia followed by reoxygenation were examined using various inhibitors of enzymatic systems in intact cells and by direct measurement of H2O2 production from isolated EC plasma membranes. Extracellular H2O2 was measured with a fluorometric assay. EC exposed to hypoxia (3% O2) and anoxia (0% O2) released less H2O2 (29.6 +/- 1.3% and 4.2 +/- 0.7%, respectively) compared with EC exposed to normoxia (20% O2). The extracellular release of H2O2 from EC previously exposed to hypoxia for 24 h increased immediately after reoxygenation (20% O2) to 272 +/- 48%, as compared with EC exposed continuously to normoxia (100% release). Inhibition of xanthine oxidase (XO) by allopurinol did not reduce the release of H2O2 from cells exposed to normoxia or hypoxia followed by reoxygenation. Furthermore, inhibitors of cyclooxygenase (indomethacin), phospholipase A2 (quinacrine and chlorpromazine), nitric oxide synthase (L-arginine analogs), the mitochondrial electron transport chain (rotenone and cyanide), and cytochrome P-450 (methoxypsoralen) had no or minimal effect on this release. On the other hand, inhibitors of protein kinase C (calphostin and staurosporine) and NADPH oxidase (diphenyliodonium) reduced the release of H2O2 from EC in a dose-dependent manner in both exposure groups. In separate experiments, plasma membranes isolated from EC were found to produce H2O2 in the presence of NADH or NADPH as electron donors. This was inhibited by diphenyliodonium but not by allopurinol.(ABSTRACT TRUNCATED AT 250 WORDS)
Alkaloids↗
Regulation of bovine endothelial constitutive nitric oxide synthase by oxygen.
Oxygen (O2) may regulate pulmonary vascular resistance through changes in endothelial nitric oxide (NO) production. To determine whether constitutive NO synthase (cNOS) is regulated by O2, we assessed cNOS expression and activity in bovine pulmonary artery endothelial cells exposed to different concentrations of O2. In a time-dependent manner, changes in O2 concentration from 95 to 3% produced a progressive decrease in cNOS mRNA and protein levels resulting in 4.8- and 4.3-fold reductions after 24h, respectively. This correlated with changes in cNOS activity as determined by nitrite measurements. Compared with 20% O2, cNOS activity was increased 1.5-fold in 95% O2 and decreased 1.9-fold in 3% O2. A decrease in O2 concentration from 94 to 3% shortened cNOS mRNA half-life from 46 to 24 h and caused a 20-fold repression of cNOS gene transcription. Treatment with cycloheximide produced a threefold increase in cNOS mRNA at all O2 concentrations, suggesting that cNOS mRNA expression is negatively regulated under basal condition. We conclude that O2 upregulates cNOS expression through transcriptional and post-transcriptional mechanisms. A decrease in cNOS activity in the presence of low O2 levels, therefore, may contribute to hypoxia-induced vasoconstriction in the pulmonary circulation.
Aerobiosis↗
Regulation of endothelial cell xanthine dehydrogenase xanthine oxidase gene expression by oxygen tension.
Recent studies have demonstrated that xanthine dehydrogenase/xanthine oxidase (XD/XO) activities of bovine endothelial cells (EC) are inversely regulated by O2 tensions to which the cells are exposed. We have confirmed these reports and extended the observation to a variety of cells from other sources. All EC that had detectable XD/XO activity demonstrated the greatest activity at the lowest O2 level. Bovine pulmonary artery smooth muscle cells showed XD/XO activity only under hypoxic conditions. The ratio of XO to XO+XD did not change significantly under various O2 concentrations for all cell types tested. Treatment of bovine pulmonary artery and rat epididymal fat pad EC with actinomycin D (1 microgram/ml), an inhibitor of transcription, suppressed XO and XO+XD activities in cells exposed both to 20 and 3% O2. High-dose cycloheximide (5 micrograms/ml), an inhibitor of translation, also reduced XO and XO+XD activities in these cells, whereas low-dose cycloheximide (0.5 microgram/ml) enhanced the stimulatory effect of hypoxia on XO+XD activity. We developed a digoxigenin-labeled probe that recognizes and hybridizes to rat XD cDNA and used it to examine the effect of O2 concentration on XD/XO mRNA expression of rat epididymal fat pad EC. XD/XO mRNA concentration was increased in cells exposed to hypoxia and decreased in cells exposed to hyperoxia compared with normoxic cells. The increase in mRNA concentration resulting from exposure to hypoxia was enhanced by cycloheximide. There was no change in XD/XO mRNA stability in cells exposed to hypoxia compared with normoxia. We conclude that the regulation of XD/XO by oxygen tension most likely occurs at the transcriptional level.
Adipose Tissue↗
Respiratory dysfunction in myasthenia gravis.
Myasthenia gravis can affect the respiratory system, causing respiratory muscle weakness, an abnormal breathing pattern, and blunted ventilatory responses. Specific treatment can reverse most of these effects and prevent the development of respiratory failure.
Diagnosis, Differential↗
Mechanism of basal and transforming growth factor beta 1 stimulated H2O2 release by endothelial cells.
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5,8,11,14-Eicosatetraynoic Acid↗
Upper airway obstruction due to inhalation of a tracheal T-tube resulting in pulmonary edema.
Acute upper airway obstruction may present with pulmonary edema. Following is a report of pulmonary edema secondary to acute upper airway obstruction due to inhalation of a Montgomery tracheal T-tube. The principal factor causing pulmonary edema is the generation of large negative transpulmonary pressures. This may be enhanced by changes in the cardiovascular function due to the Müller maneuver.
Aged↗