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1.
Legionella pneumophila causes community-acquired pneumonia with high mortality, but little is known about its interaction with the alveolar epithelium. The aim of this study was to investigate whether L. pneumophila infection of lung epithelial cells (A549) resulted in pro-inflammatory activation. L. pneumophila infection induced liberation of interleukin (IL)-2, -4, -6, -8 and -17, monocyte chemoattractant protein-1, tumour necrosis factor-alpha, IL-1beta, interferon-gamma and granulocyte colony-stimulating factor, but not of IL-5, -7, -10, -12 (p70) or -13 or granulocyte-macrophage colony-stimulating factor. The present study focused on IL-8 and found induction by L. pneumophila strains 130b, Philadelphia 1, Corby and, to a lesser extent, JR32. Knockout of dotA, a central gene involved in type IVB secretion, did not alter IL-8 induction, whereas lack of flagellin significantly reduced IL-8 release by Legionella. Moreover, p38 mitogen-activated protein kinase (MAPK) was activated and kinase inhibition reduced secretion of induced cytokines, with the exception of IL-2 and granulocyte colony-stimulating factor. In contrast, inhibition of the MAPK kinase 1/extracellular signal-regulated kinase pathway only reduced the expression of a few cytokines. L. pneumophila also induced binding of nuclear factor-kappaB subunit RelA/p65 and RNA polymerase II to the il8 promoter, and a specific inhibitor of the inhibitor of nuclear factor-kappaB complex dose-dependently lowered IL-8 expression. Taken together, Legionella pneumophila activated p38 mitogen-activated protein kinase- and nuclear factor-kappaB/RelA pathway-dependent expression of a complex pattern of cytokines by human alveolar epithelial cells, presumably contributing to the immune response in legionellosis.  相似文献   

2.
We previously have described the ability of alpha-thrombin (the native procoagulant enzyme) to stimulate adherence of neutrophils to pulmonary artery endothelial cells. In the present study, we observed that conditioned medium factors released by alpha-thrombin (10(-8) M) treatment of cultured ovine pulmonary artery endothelial cells increased neutrophil adherence to naive pulmonary artery endothelial monolayers. This effect was independent of any residual alpha-thrombin present in the medium. In contrast to thrombin-induced neutrophil adherence, adherence of neutrophils mediated by the conditioned medium was not inhibited by the anti-CD18 monoclonal antibody 60.3, indicating a CD18-independent mechanism. The factors generated by the action of alpha-thrombin on endothelial cells also resulted in concentration-dependent neutrophil migration. The neutrophil adherence- and migration-promoting activities were isolated in the ether portion after extraction of the conditioned medium. Chromatographic analysis showed that the active components (which resolved into two peaks by reversed-phase high-performance liquid chromatography) were relatively hydrophilic low molecular weight lipids without phosphorus or amino acids. Reconstitution of these peaks indicated that they mediated neutrophil adhesion and migration responses. The results indicate that lipid factors promoting neutrophil adhesion and migration are generated by the action of thrombin on pulmonary artery endothelial cells. The generation of these factors may contribute to the amplification of the lung inflammatory response after pulmonary intravascular coagulation induced by thrombin.  相似文献   

3.
Lynam  EB; Simon  SI; Rochon  YP; Sklar  LA 《Blood》1994,83(11):3303-3311
Human neutrophils are primed in the presence of complexes of lipopolysaccharide (LPS) with its serum binding protein (LBP) in a manner dependent on CD14. Cellular consequences of priming include increased responsiveness, the upregulation of surface proteins including the adhesive integrin CD11b/CD18 (Mac-1), the increased binding of certain ligands to CD11b/CD18, and the concurrent shedding of the L-selectin homing receptor. Because expression of both CD11b/CD18 and L-selectin is obligatory for formyl peptide-stimulated neutrophil aggregation in vitro (Simon et al, Blood 82:1097, 1993), we have examined the consequences of bacterial endotoxin on the expression of neutrophil adhesive molecules. We observed that the exposure of neutrophils to LPS/LBP, while enhancing the surface numbers and adhesive function of CD11b/CD18 for latex particles, did not induce aggregation. In contrast, as the LPS/LBP concentration increased (ED50 = 30 ng/mL LPS/LBP), the ability of neutrophils to aggregate decreased in parallel with the shedding of L-selectin. Moreover, when L-selectin adhesive activity was blocked by treatment with Fab fragments of Dreg- 200, aggregation was inhibited to an extent roughly proportional to the available L-selection. Blocking of LPS/LBP with CD14-specific monoclonal antibodies suppressed L-selectin shedding and preserved formyl peptide-stimulated aggregation. Taken together, the data suggest that inhibition of neutrophil aggregation by LPS/LBP is related to the expression of L-selectin via CD14 rather than LPS inhibition of CD11b/CD18 function during cellular stimulation.  相似文献   

4.
Prostaglandin E1 (PGE1) has been shown to inhibit acute inflammatory reactions involving vascular permeability changes and subsequent tissue damage caused by immune complex deposition and other inflammatory mediators. These effects have been postulated to be due to functional changes induced in circulating neutrophils by PGE1. We evaluated the ability of PGE1 (1 to 100 microM) to protect endothelial cells (EC) from neutrophil injury induced by C5a or phorbol myristate acetate (PMA). The injury to endothelial monolayers was quantitated by 51Cr loss after an 18-h incubation. In the presence of PGE1, there was a concentration-dependent inhibition of C5a- or PMA-stimulated human neutrophil injury to EC. The protective effect was more effective by pretreatment of neutrophils than EC. Since neutrophil adherence to endothelial cells is thought to be an early event in the sequence resulting in injury to vascular endothelium, we next evaluated the effect of PGE1 on neutrophil adherence to plastic surfaces and EC. In a similar fashion, there was a concentration-dependent inhibition of neutrophil adherence to plastic and EC following stimulation with PMA (10 ng/ml), human C5a (5 micrograms/ml) or formyl-met-leu-phe (FMLP, 2 x 10(-7) M). To investigate a possible mechanism of inhibition of neutrophil adherence to plastic surfaces or EC, expression of the neutrophil surface protein Mo1, previously shown to be associated with increased granulocyte adherence, was measured by fluorescence flow cytometry. Although basal levels of Mo1 expression by unstimulated neutrophils were diminished by PGE1 treatment, there was no significant inhibition of PMA- or FMLP-stimulated Mo1 expression in PGE1-treated neutrophils compared with neutrophils stimulated in the absence of PGE1.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

5.
OBJECTIVES: The glycoprotein P-selectin is an adhesion molecule that is rapidly expressed on the surface of platelets and endothelium during the inflammatory process. P-selectin on endothelium has been reported to play an important role in reperfusion injury. However, little is known regarding P-selectin on platelets in contributing to the pathophysiology of myocardial reperfusion injury. In this study, we hypothesized that P-selectin on platelets may enhance neutrophil endothelial adherence and this may play a role in neutrophil-mediated reperfusion injury. METHODS: Endothelial cells, cardiomyocytes, platelets and neutrophils were isolated from adult rats. Endothelial cells and cardiomyocytes were cultivated in a co-culture system. After exposure to hypoxia and reoxygenation, neutrophil adherence and migration were examined. RESULTS: After exposure to 6 h of hypoxia, endothelial cells co-incubated with platelets showed significantly greater neutrophil adherence (63.1 +/- 4.0%) and migration (78.2 +/- 6.7%) than endothelial cells alone (adhesion: 44.2 +/- 2.8%, migration: 57.9 +/- 4.9%). These increases were significantly inhibited (adhesion: 42.1 +/- 3.5%, migration: 65.5 +/- 3.8%) by an anti-P-selectin monoclonal antibody. Moreover, the superoxide-anion production was significantly elevated when activated platelets were added to neutrophils. This enhanced production was also inhibited by anti-P-selectin antibody. CONCLUSION: The presence of activated platelets enhanced neutrophil adhesion and migration process after hypoxia reoxygenation. This process may occur following platelet-neutrophil interactions via P-selectin and subsequent neutrophil activation.  相似文献   

6.
BACKGROUND: The nonparenchymal cells of the liver have been suggested to play a significant role in the inflammatory processes observed in the development and/or progression of alcoholic liver disease. Our laboratories have shown that malondialdehyde-acetaldehyde (MAA)-modified proteins can induce immune responses, cytokine/chemokine secretion, and antigen processing and presentation by liver sinusoidal endothelial cells (SECs). Another molecule that has been shown to induce similar types of responses in Kupffer cells (KCs) is lipopolysaccharide (LPS). Because these materials induce similar responses, it was the purpose of this study to investigate the relationship between LPS and MAA-modified proteins in the development of proinflammatory responses by SECs and KCs. METHODS: For these studies, SECs and KCs were isolated from chow-fed, pair-fed, and ethanol-fed rats. Cells were stimulated with media alone, bovine serum albumin (Alb), or MAA-modified Alb (MAA-Alb) in the presence or absence of LPS 1 ng/ml, and the supernatants were assayed by enzyme-linked immunosorbent assay for tumor necrosis factor alpha, macrophage chemotactic protein 1, and macrophage inhibitory protein. RESULTS: All three cytokines/chemokines were 3 to 5 times higher when SECs or KCs were stimulated by MAA-Alb in the presence of LPS, in contrast to cells stimulated with Alb or media in the presence of LPS. Chronic ethanol consumption (6 weeks) had variable effects on the secretion of these cytokines/chemokines but in general did not alter the increased secretion in response to MAA-Alb in the presence of LPS. CONCLUSIONS: These studies strongly suggest that the sensitization of SECs and KCs by LPS plays a significant role in the development and/or progression of alcoholic liver disease, and the subsequent activation by MAA-modified proteins may be a mechanism by which proinflammatory processes are initiated.  相似文献   

7.
We examined which endothelial second messengers are involved in peroxide-mediated endothelial-neutrophil adhesion with respect to endothelial P-selectin expression and platelet-activating factor (PAF). Peroxide (0.5 mM)-mediated adhesion was blocked by a protein kinase C (PKC) inhibitor, G?6976 (10 nM); an intracellular calcium chelator, TMB-8 (0.1 mM); and a protein kinase G (PKG) inhibitor, KT5823 (0.5 microM); but not by a tyrosine kinase inhibitor, genistein (1 microM), or a protein kinase A inhibitor, H-89 (0.1 microM). These data were consistent with the proadhesive effects of PMA (0.1 microM), a PKC activator; a calcium ionophore, A23187 (1 microM); and dibutyryl cGMP (0.5 and 1 mM); but not phenylarsine oxide (0.1 mM), a tyrosine phosphatase inhibitor, or dibutyryl cAMP (1 mM). Conversely, peroxide-mediated P-selectin expression was blocked by G?6976 and KT5823, but not by TMB-8. These data are strengthened by the observation that PMA and dibutyryl cGMP, but not A23187, increased P-selectin expression. WEB 2086 (10 microM), a PAF-receptor antagonist, blocked peroxide-, PMA-, and A23187-mediated adhesion, but not peroxide-mediated P-selectin expression. PAF itself (10 nM) stimulated adhesion, but not P-selectin expression. These data indicate that PKC and PKG are involved in peroxide-mediated neutrophil adhesion via P-selectin mobilization and PAF synthesis; however, intracellular calcium appears to mediate adhesion only through PAF synthesis.  相似文献   

8.

Background

Neural pathways are thought to be directly involved in the pathogenesis of rheumatoid arthritis (RA). Although synovial mast cells (MCs) are activated by substance P (SP), the role of MCs in neural pathways in RA remains unknown. The aims of this study were to investigate 1) whether tachykinins are produced by synovial MCs and whether production differs in RA and osteoarthritis (OA) patients, and 2) what is the responsible receptor for SP in synovial MCs.

Methods

Synovial tissues were obtained from patients with RA or OA undergoing joint replacement surgery. Cultured synovium-derived MCs were generated by culturing dispersed synovial cells with stem cell factor. SP expression was investigated using immunofluorescence and enzyme immunoassays. Mas-related gene X2 (MrgX2) expression was reduced in human MCs using a lentiviral shRNA silencing technique.

Results

SP expression was localized around the cell membrane in 41% (median) of the MCs in synovium from RA but in only 7% of that from OA, suggesting the activation of MCs. Synovial MCs expressed tachykinin (TAC) 1 mRNA, the expression of which was upregulated by the aggregation of Fc?RI or the addition of aggregated IgG. However, the released SP appeared to be rapidly degraded by MC chymase. Synovial MCs were activated with SP through MrgX2 to release histamine without producing proinflammatory cytokines.

Conclusions

Activated synovial MCs may rapidly degrade SP, which may downregulate the SP-mediated activation of synoviocytes in RA. On the other hand, SP activates MCs to induce inflammatory mediators, suggesting the dual regulation of SP-mediated inflammation by MCs in RA.  相似文献   

9.
Exposure of cultured bovine pulmonary artery endothelial cells to hyperoxia (95% O2) caused cellular injury manifested by decreased growth rates and release of cytoplasmic lactic dehydrogenase (LDH). In addition, a greater number of polymorphonuclear leukocytes (PMN) adhered to endothelial cells that had been exposed to hyperoxia for 24 or 48 h than to control endothelial cells that had been exposed to normoxia (15% O2). Direct endothelial cell injury from hyperoxia may contribute to vascular damage and the increased PMN accumulation seen in lungs of animals exposed to hyperoxia.  相似文献   

10.
The adherence of neutrophils (PMN) to endothelium is a crucial early step in neutrophil-mediated vascular injury. However, vascular injury is not a necessary event in inflammatory states, which suggests that endogenous mechanisms may protect endothelial cells from neutrophil-mediated injury. Previous studies suggested that leukocytes adhered in greater numbers to vascular endothelium in vivo and in vitro, where the contiguity of the cells was disrupted and where endothelial cells were actively migrating and proliferating. We studied the effect of development of a confluent monolayer on adherence of human PMN to cultured bovine calf aortic endothelial cells and investigated several mechanisms by which this effect might occur. We found that adherence of quiescent and activated PMN decreased with development of a confluent endothelial cell monolayer. A similar effect was found using human umbilical-vein endothelial cells. In contrast, adherence of nylon wool-nonadherent, thymus-derived lymphocytes increased. Variation in neutrophil adherence was not due to adherence of PMN to exposed tissue culture plastic or to exposed matrix components in preconfluent cultures, nor due to products released into culture supernatants. Diminished PMN adherence to postconfluent monolayers may have been related to changes in endothelial cell glycoproteins because neuraminidase or cycloheximide pretreatment augmented PMN adherence to postconfluent cultures more than to preconfluent cultures. However, the extent of total cell surface sialation, as assessed by neuraminidase-releasable [3H]glucosamine from metabolically labeled monolayers, did not differ between pre- and postconfluent cultures, suggesting that some specific sialated cell surface constituent is responsible for decreased PMN adherence to postconfluent monolayers.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
12.
AIM: To determine if primary murine colonic epithelial cells (CEC) respond to commensal bacteria and discriminate between different types of bacteria. METHODS: A novel CEC: bacteria co-culture system was used to compare the ability of the colonic commensal bacteria, Bacteroides ovatus, E coli(SLF) and Lactobacillus rhamnosus (LGG) to modulate production of different cytokines (n = 15) by primary CEC. Antibody staining and flow cytometry were used to investigate Toll-like receptor (TLR) expression by CEC directly ex vivo and TLR responsiveness was determined by examining the ability of TLR ligands to influence CEC cytokine production. RESULTS: Primary CEC constitutively expressed functional TLR2 and TLR4. Cultured in complete medium alone, CEC secreted IL-6, MCP-1 and IP-10 the levels of which were significantly increased upon addition of the TLR ligands peptidoglycan (PGN) and lipopolysaccharide (LPS). Exposure to the commensal bacteria induced or up-regulated different patterns of cytokine production and secretion.E coli induced production of MIP-1α/β and p defensin3 whereas B. ovatus and L. rhamnosus exclusively induced MCP-1 and MIP-2α expression, respectively. TNFa, RANTES and MEC were induced or up-regulated in response to some but not all of the bacteria whereas ENA78 and IP-10 were up-regulated in response to all bacteria. Evidence of bacterial interference and suppression of cytokine production was obtained from mixed bacterial: CEC co-cultures. Probiotic LGG suppressed E coli- and B. ovatus-induced cytokine mRNA accumulation and protein secretion. CONCLUSION: These observations demonstrate the ability of primary CEC to respond to and discriminate between different strains of commensal bacteria and identify a mechanism by which probiotic bacteria (LGG) may exert anti-inflammatory effects in vivo.  相似文献   

13.
BACKGROUND/AIMS: Several observations point to an important role of interactions between polymorphonuclear neutrophils and cytokines in severe alcoholic hepatitis. The polymorphonuclear neutrophil activation status and the local and systemic pro- and anti-inflammatory cytokine responses were quantified. The effect of corticosteroids, widely used in this setting, was evaluated using these parameters. METHODS: We studied blood polymorphonuclear neutrophil functions in terms of L-selectin and beta2-integrin expression, H2O2 production and IL-8 and tumor necrosis factor alpha synthesis capacity. We also measured IL-8, tumor necrosis factor alpha and IL-10 plasma and liver tissue levels. Fifteen patients with alcoholic hepatitis were compared to 15 patients with alcoholic cirrhosis without alcoholic hepatitis, and to 10 healthy volunteers. The impact of a 28-day course of corticosteroids on blood neutrophils activation status and cytokine levels was evaluated in patients with alcoholic hepatitis. RESULTS: Blood polymorphonuclear neutrophils were activated, as shown by increased H2O2 production (48+/-6 vs 29+/-6 MFI in healthy controls), and decreased L-selectin expression (300+/-61 vs 449+/-59 in healthy controls). Upon stimulation, polymorphonuclear neutrophils synthesized large amounts of IL-8 (21.7+/-9.2 ng/ml vs 8.8+/-10 ng/ml in healthy controls) and tumor necrosis factor alpha (524+/-132 pg/ml vs 79+/-144 pg/ml in healthy controls). Tumor necrosis factor alpha and IL-8 plasma and tissue levels were markedly increased as IL-10 was barely detectable in alcoholic hepatitis patients, compared to cirrhotic patients and healthy controls. During steroid therapy, plasma levels of the pro-inflammatory cytokine IL-8 fell as early as day 14, while levels of the anti-inflammatory cytokine IL-10 increased on day 21. Finally, polymorphonuclear neutrophil functions returned to normal after treatment. CONCLUSION: Severe alcoholic hepatitis appears to be associated with polymorphonuclear neutrophil activation and an imbalance between pro- and anti-inflammatory cytokines; during steroid therapy a normalization of these parameters was observed.  相似文献   

14.
The role of urease in Helicobacter pylori adherence to and internalization by Kato III cells was investigated. Kato III cells were incubated with wild-type strains (N6 or P1), with isogenic mutants lacking urease (N6ureB::TnKm or P1ureA::TnMax5) or producing the inactive apoprotein (N6ureG::TnKm), and with urease-positive clones recovered after complementation of N6ureB::TnKm with ureAB. Bacteria were stained with the green fluorescent dye PKH2, and the bacteria load of cells was analyzed by flow cytometry. With mutants lacking urease, the bacteria load was considerably increased, in comparison with the corresponding parental strains (P<.001). With clone K2(3), producing larger amounts of urease than N6, a significant reduction of bacteria load was observed, in comparison with the wild type (P<.001). N6ureG::TnKm showed adherence characteristics similar to those of N6. The role of urease in internalization was not clear. Thus, urease significantly inhibits H. pylori adherence to Kato III cells by a mechanism largely independent of enzymatic activity.  相似文献   

15.
The role of adherence in the pathogenicity of Branhamella catarrhalis in lower respiratory tract infection in the elderly was investigated. Differential adherence of this organism to buccal epithelial cells of elderly inpatients, outpatients, and young controls was measured. The mean number of bacteria adherent per cell was 36.9 +/- 11.2, 40.2 +/- 6.1 and 16.5 +/- 12.8 for inpatient and outpatient elderly and young controls respectively (significantly different p less than 0.01, Student's t test). This significantly higher level of adherence in the elderly subjects suggests that increased adherence may contribute to the incidence of respiratory tract infection due to B. catarrhalis seen in this group.  相似文献   

16.
17.
目的 探讨活化血小板通过表达CD15 4分子对单核细胞与内皮细胞黏附作用的影响。方法 以不同浓度二磷酸腺苷 (ADP) ,凝血酶体外诱导血小板活化 ,应用流式细胞术测定血小板CD6 2P、CD15 4表达水平 ,分析血小板表达CD15 4与其活化的关系 ;并将诱导或未经诱导的血小板与培养的人脐静脉内皮细胞 (HUVECs)共育 ,应用流式细胞术及ELISA法分别检测HUEVCs产生膜性及可溶性细胞间黏附分子 1(ICAM 1)的水平及变化 ,以孟加拉玫瑰红活细胞染色法测定单核细胞与HUVECs的黏附。结果 血小板活化程度与其CD15 4表达水平间呈显著正相关 (P <0 0 5 )。ADP(4μmol/L)或凝血酶 (1U/ml)诱导的血小板 ,均能显著增强单核细胞与HUVECs的黏附 ,并促进HUVECs产生膜性及可溶性ICAM 1(P <0 0 5、0 0 1) ,应用特异性CD15 4单抗后可阻断上述作用。静息血小板、单纯等量ADP或凝血酶 ,对HUVECs表达ICAM 1及单细胞与HUVECs的黏附均无影响 (P>0 0 5 )。结论 活化血小板可通过表达CD15 4促进单核细胞与内皮细胞的黏附 ,由此引发的炎症反应可能在动脉粥样硬化形成及不稳定斑块破裂方面发挥重要作用。  相似文献   

18.
The adherence of Pseudomonas aeruginosa strains to human epithelial cells from the buccal mucosa, large intestine and urinary tract was studied. Strains resistant to gentamicin and carbenicillin, derived by laboratory training, exhibited enhanced adherence as compared to their sensitive parent strain. The same was found with a strain showing an R-factor acquired resistance to gentamicin. This phenomenon was observed with all epithelial cells tested regardless of their anatomical origin. These results suggest that resistant strains of P. aeruginosa are more likely to colonise mucosal surfaces.  相似文献   

19.
OBJECTIVE: To determine if methotrexate (MTX) induces human lung fibroblast (HFL-1) and epithelial (BEAS 2B) cell lines to release eosinophil chemotactic activity (ECA). METHODS: HFL-1 and BEAS 2B cell supernatant fluids were evaluated for ECA by a blind well chamber technique. RESULTS: HFL-1 and BEAS-2B cells released ECA in a dose and time dependent manner in response to MTX. Partial characterization revealed that ECA was partly heat labile, trypsin sensitive, and ethylacetate extractable. Thus the culture supernatant fluids were evaluated for known eosinophil chemotactic factors. Although several were released constitutively, granulocyte-macrophage colony-stimulating factor (GM-CSF) was significantly increased in response to MTX from both cell types. Consistent with these observations, ECA from both cell types was inhibited by GM-CSF antibodies. CONCLUSION: These data suggest that lung fibroblasts and epithelial cells may modulate eosinophil recruitment into the lung by releasing ECA in response to MTX.  相似文献   

20.
Methotrexate-induced pneumonitis has been reported as an infrequent but potentially serious complication of therapy in a variety of malignant and benign conditions. Because inflammatory cell infiltration is concerned with the development of methotrexate-induced pneumoinitis, and because airway epithelial cells participate in the orchestration of lung inflammation, the authors determined whether methotrexate might stimulate airway epithelial cells (A549 cells) to release neutrophil, monocyte, and eosinophil chemotactic activities (NCA, MCA, and ECA). A549 cells released NCA, MCA, and ECA in a dose- and time-dependent manner in response to methotrexate. Partial characterization revealed the heterogeneity of NCA, MCA, and ECA. The release of chemotactic activity was blocked by lipoxygenase inhibitors and cycloheximide. NCA was inhibited by leukotriene (LT) B(4) receptor antagonist, and anti-interleukin (IL)-8 and granulocyte colony-stimulating factor (G-CSF) antibodies. MCA was attenuated by LTB(4) receptor antagonist, and anti-monocyte chemoattractant protein (MCP)-1 and granulocyte-macrophage CSF (GM-CSF) antibodies. ECA was attenuated by LTB(4) receptor antagonist, and anti-IL-8 and GM-CSF antibodies. The release of IL-8, G-CSF, MCP-1, GM-CSF, and LTB(4) from A549 cells significantly increased in response to methotrexate. The mRNA expression of IL-8 and MCP-1 was augmented by methotrexate stimulation. These data suggest that type II epithelial cells may modulate inflammatory cell recruitment into the lung by releasing NCA, MCA, and ECA in response to methotrexate.  相似文献   

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