Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bacterial peritonitis is the most important complication of peritoneal dialysis (PD), limiting its widespread application. Conventional glucose-based peritoneal dialysates (G-PDS) depress oxygen consumption, chemiluminescence, superoxide production, phagocytosis, bacterial killing and actin polymerization in neutrophils (PMN) in vitro. Expression of adhesion receptors is critical to leukocyte activation, adhesion, migration and phagocytosis. The effects of G-PDS on basal and stimulated leukocyte adhesion molecule expression and leukocyte adhering capacity is unknown. We examined the effect of a five minutes incubation of whole blood in either HEPES-buffered saline or G-PDS containing 1.5% (83 mM), 2.5% (139 mM) or 4.25% (236 mM) glucose, at pH = 5.2, and pH = 7.4. PMN intracellular pH was measured spectrofluorometrically. Leukocyte CD11b, CD18 and CD14 were measured by flow cytometry using monoclonal antibodies in otherwise unstimulated cells or 60 minutes after lipopolysaccharide (LPS) stimulation. In addition, leukocyte adhering capacity to nylon wool was tested. In an attempt to dissect the effect of high glucose concentrations from that of the attendant hyperosmolality, the experiments were repeated with dialysates in which glucose was substituted by sodium chloride (NaCl-PDS) to attain identical osmolalities. G-PDS, as well as the mixtures of spent and fresh G-PDS, significantly depressed the basal PMN expression of adhesion receptors CD11b and CD18 and monocyte expression of CD14, and substantially mitigated the LPS-mediated up-regulation of CD11b and CD18. Likewise, G-PDS significantly inhibited leukocyte adhering capacity without affecting cell viability. Similar results were observed with NaCl-PDS. The observed abnormalities were primarily osmolality-dependent, and largely intra- and extracellular pH-independent. Impaired adhesion receptor expression and cell adhesion capacity shown here reveal another dimension of the G-PDS-induced leukocyte abnormalities.
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PMID:Effects of conventional peritoneal dialysates on leukocyte adhesion and CD11b, CD18 and CD14 expression. 891 36

To clarify whether the inducible nitric oxide synthase (iNOS) protein can be induced in in vivo brain, we examined the influence of direct intrahippocampal injection with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS) in the rat. In the area surrounding the microinjection site, NOS activity (NO2- accumulation) was enhanced 24 h after injection with IFN-gamma plus LPS. Although the level of 160-kDa nNOS protein was not changed, the 130-kDa iNOS protein was induced 12 h after the injection. On the other hand, iNOS mRNA could be detected at 6 and 12 h but not at 24 h. iNOS immunoreactivity was observed in CD11b-immunopositive microglia in close proximity to the injection site, but the immunoreactivity was not colocalized with glial fibrillary acidic protein-immunopositive astrocytes. Although CD11b-immunopositive microglia were of the ramified type even after injection with vehicle after 24 h, injection with IFN-gamma plus LPS caused numerous microglia to change to the ameboid type and to express major histocompatibility complex (MHC) class II antigens. In some of these ameboidal microglia, iNOS immunoreactivity was observed. These results suggest that intrahippocampal injection with IFN-gamma plus LPS induced iNOS mRNA after 6 h and iNOS protein after 12 h in some of the ameboidal microglia that expressed MHC class II antigens in in vivo rat brain.
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PMID:In vivo induction of inducible nitric oxide synthase by microinjection with interferon-gamma and lipopolysaccharide in rat hippocampus. 891 55

The functions of different populations of peripheral blood monocytes in the course of an inflammatory reaction are presently not fully understood. In particular, the mechanisms for their specific recruitment to an inflammatory site are not yet known. We investigated a dexamethasone (Dex)-inducible monocyte subtype and its adhesion to either unstimulated or lipopolysaccharide (LPS)- or interferon (IFN)-gamma-stimulated human umbilical vein endothelial cells (HUVEC). The Dex-induced monocytes were characterized by the expression of the surface glycoprotein RM3/1. It was found that pretreatment of monocytes with Dex increased their adhesion to unstimulated and stimulated HUVEC. This increase in adhesion was paralleled by the expression of the RM3/1 surface molecule. Treatment with cyclosporin A (CsA) caused a down-regulation of the RM3/1 density per cell by 67% and also decreased adhesion to HUVEC. In contrast, the expression of other adhesion molecules remained unaffected by Dex or CsA treatment. Treatment of Dex-induced monocytes with antibodies against RM3/1, CD11a, CD11b, CD11c, CD14 and CD18 resulted in suppression of adhesion to stimulated HUVEC by 46%, 18%, 17%, 12%, 25% and 15%, respectively. Antibodies to the known adhesion molecules on endothelial cells (vascular cell adhesion molecule-1, E-selectin) did not block adhesion of Dex-induced monocytes. However, the combination of antibodies to RM3/1 and CD14 inhibited adhesion to LPS-stimulated HUVEC by 74%. These effects were also seen on IFN-gamma-stimulated HUVEC, where adhesion of Dex-induced monocytes was blocked with antibodies to RM3/1 + CD14 by 63%. From this, it is concluded that the RM3/1-molecule is a novel surface molecule that contributes to the adhesion of cortisone-induced monocytes to LPS or cytokine-stimulated endothelial cells.
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PMID:Identification of a novel surface molecule, RM3/1, that contributes to the adhesion of glucocorticoid-induced human monocytes to endothelial cells. 892 66

Exposure of neutrophils to agents such as lipopolysaccharide, tumor necrosis factor-alpha (TNF-alpha), and the granulocyte-macrophage colony-stimulating factor causes a major upregulation of subsequent agonist-induced NADPH oxidase activation. This priming effect is a prerequisite for neutrophil-mediated tissue damage and has been widely considered to be an irreversible process. We have investigated the potential for neutrophils to recover from a priming stimulus by studying the effects of platelet-activating factor (PAF). PAF did not stimulate respiratory burst activity directly, but caused a rapid (maximal at 10 minutes) and concentration-dependent (EC50 50.2 nmol/L) increase in N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated superoxide anion release. At time-points > 10 minutes, this priming effect spontaneously declined, with return to basal levels of fMLP-stimulated superoxide anion generation by 120 minutes. An identical priming time-course was observed with N-methyl carbamyl PAF, a nonmetabolizable analogue of PAF, indicating that the transient nature of PAF-induced priming was not secondary to PAF metabolism. Two structurally diverse PAF receptor antagonists (UK-74,505 and WEB 2086), added 10 minutes after PAF addition, increased the rate of decay of the priming effect. In contrast, TNF-alpha-induced priming, which was of a similar magnitude to that observed for PAF, was slower to evolve (maximal at 30 minutes) and remained constant for at least 120 minutes. The reversible nature of PAF-induced priming was confirmed by demonstrating that PAF-, but not TNF-alpha-, induced cell polarization (shape change) and CD11b-dependent neutrophil binding of albumin-coated latex beads was also transient, with return to basal, unstimulated levels by 120 minutes. Furthermore, cells that had spontaneously deprimed following PAF exposure retained their capacity to be fully reprimed by a subsequent addition of either PAF or TNF-alpha. These data imply that neutrophil priming is not an irreversible event: the demonstration of a cycle of complete priming, depriming, and repriming offers the potential for functional recycling of neutrophils at sites of inflammation.
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PMID:Demonstration of reversible priming of human neutrophils using platelet-activating factor. 894 70

The acyl poly(1,3)galactoside (APG) from Klebsiella pneumoniae is a bis-acylated lipopolysaccharide (LPS) devoid of ester-linked fatty acids. APG interacts with CD14 and CD11b/CD18 on monocytes. This study addressed the role of serum proteins in the binding and functional properties of APG as a candidate LPS antagonist. In the absence of serum, APG did not induce tumor necrosis factor alpha (TNF-alpha) synthesis by human mononuclear cells and dose-dependently inhibited their activation induced by different LPS. Conversely, in the presence of 5% autologous plasma, APG activated cells and did not antagonize LPS. Serum decreased APG but not LPS binding to monocytes. Binding competition experiments indicated that APG and LPS competed for the same receptors in serum-free conditions but bound to different receptors in the presence of plasma. The data indicate that serum-dependent LPS receptors do contribute to LPS activation of monocytes but do not recognize deacylated LPS analogues.
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PMID:Alteration of dealcylated lipopolysaccharide antagonistic properties by interaction with plasma factors. 900 May 32

The bacterial and serum factors involved in the oxidative response triggered by Salmonella typhimurium in differentiated U937 cells were investigated. Complement activation was shown to be required, using sera deficient in complement factors. An original dot-blot technique was developed to study the activation of complement by either bacteria or purified lipopolysaccharide (LPS). Both O-specific and lipid A segments of LPS were found to play a role in the triggering of the oxidative response. Lipid A was responsible for bacterial C3-derived opsonization by inducing an antibody-independent activation of complement classical pathway, whereas O-specific polysaccharide chains (O-Ag) were involved in cellular activation. Inhibition experiments using anti-cell surface marker monoclonal antibodies showed the involvement of the alpha chain of CR3 (CD11b) in the oxidative response developed by differentiated U937 cells in response to S. typhimurium infection. Whether both iC3b and O-Ag interact with different domains of CR3 or whether the binding of O-Ag occurs via a not yet identified receptor remains to be determined.
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PMID:The oxidative burst triggered by Salmonella typhimurium in differentiated U937 cells requires complement and a complete bacterial lipopolysaccharide. 901 44

A reconstituted high density lipoprotein (rHDL) containing human apolipoprotein A-I and phosphatidylcholine was tested for its ability to modify polymorphonuclear leukocyte (PMN) adherence to endothelial cells (EC) in vitro. EC stimulation for 4 h with lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF alpha) resulted in a four- to sixfold increase in PMN adherence. Concomitant stimulation of EC with LPS and rHDL virtually prevented the LPS-stimulated increase in PMN adherence. Changes in adherence were paralleled by alterations in adhesion molecule expression of EC. Concomitant EC stimulation with LPS and rHDL resulted in complete inhibition of the LPS-stimulated increase in expression of E-selectin and intercellular adhesion molecule 1 (ICAM-1). In contrast, rHDL reduced the TNF alpha-induced expression of adhesion molecules as well as the PMN adherence to TNF alpha-stimulated EC by approximately 10%. The CD11/CD18-mediated PMN adherence to EC as a consequence of PMN stimulation with calcium ionophore (A23187) was diminished in the presence of rHDL after 7 min incubation by 36.1 +/- 11.4% and after 15 min incubation by 45.1 +/- 7.4%. In addition, the A23187-stimulated increase in PMN adherence to fibrinogen-coated surfaces, mediated by CD11b/CD18, was virtually eliminated in the presence of rHDL and HDL, but not in the presence of apolipoprotein A-I or natural low density lipoprotein. FACS analysis showed that PMN treated with rHDL and subsequently washed were resistant to FMLP-induced CD11b/ CD18 up-regulation. In conclusion, these data indicate that rHDL decreases cell adhesion via two mechanisms: blocking LPS activity and modifying CD11b/CD18 up-regulation on PMN.
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PMID:Reconstituted high density lipoprotein modulates adherence of polymorphonuclear leukocytes to human endothelial cells. 906 82

Theileria annulata is a tick-transmitted protozoan parasite of cattle, which transforms cells of macrophage (Mphi) or B cell lineage. Bone marrow cells, bone marrow cell-derived, and monocyte-derived Mphi were infected with T. annulata sporozoites, and the resulting cell lines were assessed for surface marker expression and function. Transformed lines expressed histocompatibility complex (MHC) class-I and II, CD44, CD45, and the myeloid marker DH598-surface markers CD14, CD11b, M-M7, TH57A, and to a lesser extent CD11a/CD18, CD11c, and ACT(B), were down-regulated. Likewise, transformed cells failed to express Mphi functions (Fc-receptor-mediated phagocytosis, phorbol myristate acetate-induced oxidative burst, lipopolysaccharide-induced tumor necrosis factor alpha, and nitric oxide generation and procoagulant activity up-regulation). Mphi origin was assured by homogeneity of the starting population, cloning of cells by limiting dilution, and repeated microscopic and flow cytometric monitoring of the cell lines. Elimination of the parasite by treatment with BW720c resulted in the re-acquisition of monocyte lineage properties, as evidenced by up-regulation of CD14, and by re-acquisition of the capacity to ingest opsonized sheep red blood cells and bacteria. Thus, Mphi transformed by T. annulata appear to undergo a process of parasite-induced dedifferentiation but reassume the differentiated phenotype upon elimination of the parasite.
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PMID:Macrophage-parasite relationship in theileriosis. Reversible phenotypic and functional dedifferentiation of macrophages infected with Theileria annulata. 910 33

Six macrophage cell lines, each derived from a bone marrow macrophage colony grown in soft agar, were established by expansion of the macrophage clones in liquid culture until spontaneous transformation occurred. Four lines originated from the LPS(d) nonresponder mouse strain C3H/HeJ and two from the LPS(n) responder strain CBA/J. The cell lines adhered to plastic and glass surfaces and displayed typical macrophage functions such as phagocytosis and nonspecific esterase activity. Flow cytometry analyses showed that the lines expressed the macrophage surface markers CD11b, CD13, CD32/16, F4/80, and BM8 constitutively. A moderate expression of the adhesion receptor CD11a, but only a very low expression of its ligand CD54, was observed. A minor fraction of the cells in each line constitutively expressed MHC class II antigen, and its expression could be up-regulated in each cell line by treatment with interferon-gamma (IFN-gamma). Secretion of the inflammatory mediators nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha) after induction by three bacterial derivatives, heat-killed Salmonella typhimurium (HKS), lipopolysaccharide (LPS), and the Mycoplasma fermentans-derived amphiphilic lipid MDHM, were examined in detail. Not only did the lines differ in the amounts of mediators secreted in response to any one stimulus, but the doses of MDHM or LPS required for 50% maximal induction of NO varied up to 10-fold among the four LPS(d) cell lines, suggesting considerable functional heterogeneity between the clones. Secretion of large amounts of TNF-alpha was induced in all the cell lines by HKS. Although it could be shown that exogenously added TNF-alpha acted synergistically with IFN-gamma to induce NO release from the cell lines, an autocrine role for TNF-alpha during HKS-IFN-gamma induction of NO synthesis could not be substantiated. Neutralization of TNF-alpha with a specific antibody completely blocked NO induction by exogenous TNF-alpha but did not abrogate NO release either by HKS-IFN-gamma-induced cells or by macrophages treated with supernatant from an HKS-IFN-gamma-activated cell line. These results indicate that the clones are arrested in distinct stages of differentiation and retain some properties of normal untransformed macrophages. They should be helpful tools for investigations into macrophage function.
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PMID:Characterization of clonally derived, spontaneously transformed bone marrow macrophage cell lines from lipopolysaccharide hyporesponsive LPS(d) and normal LPS(n) mice. 910 34

Neutrophils (PMNs) from patients with thermal injury are dysfunctional for the CD11b/CD18-dependent functions of diapedesis, chemotaxis, and phagocytosis. The expression of CD11b/CD18 on normal PMNs is increased after an inflammatory stimulus. We proposed that CD11b/CD18 expression on burn patient PMNs would respond abnormally to inflammatory stimuli. PMNs were obtained from nonseptic burn patients during the second week after thermal injury. PMNs from burn patients incubated with lipopolysaccharide (LPS), N-formyl-methionyl-leucyl-phenylalanine, phorbol myristate acetate, or A23187 did not increase the expression of CD11b/CD18 to the same degree exhibited by normal PMNs. This inability to increase CD11b/CD18 was not due to differences in CD14 receptor expression, LPS binding, or factors present in the serum of burn patients. The upregulation of CD35 also was decreased on burn patient PMNs. Western blot analysis revealed decreased quantities of CD11b protein in burn patient PMNs compared with normal control PMNs. The deficiency in CD11b/CD18 expression after inflammatory stimuli may explain some of the abnormalities observed in burn PMN function.
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PMID:Neutrophils from burn patients are unable to increase the expression of CD11b/CD18 in response to inflammatory stimuli. 912 6


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