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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute phase proteins (albumin, prealbumin, transferrin, haptoglobin) and the results of spontaneous and load tests of lipopolysaccharide-positive neutrophils (LPS-PN) in peripheral blood were studied in the course of acute colitic dysentery in 34 patients. It is shown that at the height of the disease there was a fall in the levels of albumin, prealbumin, transferrin while haptoglobin levels were elevated. More persistent and pronounced changes were noted in patients with severe course of acute dysentery. In acute period of the disease there were low values of spontaneous and load LPS-PN tests depending on the disease severity. None of the above parameters returned to control levels within 5-6 days after the start of the treatment.
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PMID:[Functional activity of the liver and lipopolysaccharide-positive neutrophils of peripheral blood in patients with acute dysentery]. 899 18

The study was made of lipopolysaccharide-binding activity of peripheral blood neutrophils (LBA) and content of albumin, prealbumin, transferrin, haptoglobin in patients with mild, moderate and severe course of acute dysentery and food poisoning. Uniformity of changes in the above parameters irrespectively of etiology of acute intestinal infections is discovered. Inhibition of LBA in acute disease, the pattern of acute-phase proteins time-course changes, i.e. reduced levels of albumin, prealbumin, transferrin and elevated ones of haptoglobin, more persistent and marked in severe course were registered.
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PMID:[The dynamic levels of acute-phase proteins and of the lipopolysaccharide-bonding activity of the peripheral blood neutrophils in patients with acute intestinal infections]. 904 71

Transferrin, as the major iron-transport protein in serum and other body fluids, has a central role in managing iron the body receives. Liver is a major site of transferrin synthesis, and in this study we present evidence that liver synthesis of human transferrin is suppressed by both the toxic metal lead and bacterial lipopolysaccharide, an inducer of the hepatic acute phase response. The responses of intact endogenous transferrin in the human hepatoma cell line HepG2 and chimeric human transferrin-chloramphenicol acetyltransferase genes in transgenic mice were examined. In HepG2 cells, 35S-transferrin protein synthesis and mRNA levels were suppressed by 100 microM and 10 microM lead acetate as early as 24 h after the initial treatment. Yet, synthesis of two proteins known to respond in the hepatic acute phase reaction, complement C3 and albumin, was not altered by the lead treatment. In transgenic mouse liver, lead suppressed expression of chimeric human transferrin genes at both the protein and mRNA levels, but LPS only suppressed at the protein level. The study indicates that lead suppresses human transferrin synthesis by a mechanism that differs from the hepatic acute phase response and that lead may also affect iron metabolism in humans by interfering with transferrin levels.
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PMID:A comparison of the suppression of human transferrin synthesis by lead and lipopolysaccharide. 907 50

Thermal injury quantitatively and qualitatively alters hematopoiesis, including monocyte-macrophage lineage changes, resulting in altered mononuclear cell function. These bone marrow cells (BMCs) ultimately become fixed tissue macrophages (e.g., Kupffer cells). To study the effects of thermal injury on macrophage-hepatocyte interactions, rat BMCs were isolated 24 hours after burn injury, and myelopoiesis was induced by 7-day culture in granulocyte-macrophage colony-stimulating factor. Separate cultures included inflammatory mediators with growth factor function (IL-6 or PGE2). Cultured cells were incubated up to 96 hours with isolated normal hepatocytes (+/- lipopolysaccharide stimulation). The 96-hour exposure to postburn BMCs produced less of the acute phase proteins (APPs), C3 and transferrin, but more cytotoxicity as measured by 1-lactate dehydrogenase release. Sham BMCs cultured with added IL-6 caused higher APP release and minimal cytotoxicity, whereas burn BMCs stimulated lower APP release and retained cytotoxicity. In conclusion, myeloid cells regulate APP synthesis differently after thermal injury and may become more cytotoxic to hepatocytes.
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PMID:Thermal injury functionally alters bone marrow-derived macrophages: a study of monocyte-hepatocyte interactions. 940 84

Intraventricular macrophages encompass the supraependymal, free-floating, and epiplexus (Kolmer) cells; the supraependymal cells lie in close apposition to the ventricular ependyma, the epiplexus cells are closely associated with the choroid plexus epithelium, and the free-floating cells are at a variable distance from the epithelial surface. Although the three cell types are regarded as one cellular entity, the epiplexus cells preponderate. On scanning electron microscopy, the epiplexus cells display diverse morphological forms, ranging from round to bipolar to stellate, and bear a variable number of cytoplasmic processes. Transmission electron microscopy shows the presence of large numbers of lysosomes. The phagocytic nature of epiplexus cells is shown by their intense staining for nonspecific esterase and active uptake of tracers, e.g., horseradish peroxidase and rhodamine isothiocynate, administered intravenously or intraperitoneally. The mode of entry of these tracers in the cerebral ventricles is by way of transepithelial transport. In rats, the population of intraventricular macrophages increases steadily after birth until 17 days of age; thereafter, their cell population remains relatively unchanged. The early upsurge is attributed to proliferation of residential cells and/or influx of circulating monocytes/stromal macrophages through the process of "emperipolesis." The immunophenotypic features of intraventricular macrophages are consistent with other mononuclear phagocytes being immunoreactive for OX-42, OX-18, OX-6, and OX-1 and ED1 for the detection of CR3 receptors, MHC class I and II antigens, leucocyte common antigen, and macrophage antigen, respectively. The expression of these antigens is noticeably enhanced following the injection of lipopolysaccharide (LPS) into postnatal rats. Remarkably, the intraventricular macrophages are induced to express MHC class II (Ia) antigen after LPS or interferon-gamma injections. Furthermore, the expression of transferrin receptors as detected with OX-26 is also upregulated after these treatments. Epiplexus cells are also elicited to display a de novo expression of nitric oxide synthase-like immunoreactivity following intracerebral injection of LPS. They also respond vigorously to a single nonpenetrative blast. Results of our series of studies suggest that, besides their primary function as scavenger cells, the intraventricular macrophages partake in possible immunological responses and iron regulation in the ventricular system or the brain as a whole.
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PMID:Origin, nature, and some functional considerations of intraventricular macrophages, with special reference to the epiplexus cells. 955 Jan 36

Bacterial lipopolysaccharide (LPS) at the apical surface of polarized intestinal epithelial cells was previously shown to be transported from the apical to the basolateral pole of the epithelium (Beatty, W.L., and P.J. Sansonetti. 1997. Infect. Immun. 65:4395-4404). The present study was designed to elucidate the transcytotic pathway of LPS and to characterize the endocytic compartments involved in this process. Confocal and electron microscopic analyses revealed that LPS internalized at the apical surface became rapidly distributed within endosomal compartments accessible to basolaterally internalized transferrin. This compartment largely excluded fluid-phase markers added at either pole. Access to the basolateral side of the epithelium subsequent to trafficking to basolateral endosomes occurred via exocytosis into the paracellular space beneath the intercellular tight junctions. LPS appeared to exploit other endocytic routes with much of the internalized LPS recycled to the original apical membrane. In addition, analysis of LPS in association with markers of the endocytic network revealed that some LPS was sent to late endosomal and lysosomal compartments.
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PMID:Trafficking of Shigella lipopolysaccharide in polarized intestinal epithelial cells. 1033 Mar 99

To elucidate the pathways by which nitric oxide (NO) influences macrophage iron metabolism, the uptake, release, and intracellular distribution of iron in the murine macrophage cell line J774 has been investigated, together with transferrin receptor (TfR) expression and iron-regulatory protein (IRP1 and IRP2) activity. Stimulation of macrophages with interferon-gamma (IFN-gamma) and/or lipopolysaccharide (LPS) decreased Fe uptake from transferrin (Tf), and there was a concomitant downregulation of TfR expression. These effects were mediated by NO-dependent and NO-independent mechanisms. Addition of the NO synthase (NOS) inhibitor N-monomethyl arginine (NMMA) partially restored Fe uptake but either had no effect on or downregulated TfR expression, which suggests that NO by itself is able to affect iron availability. Analysis of the intracellular distribution of incorporated iron revealed that in IFN-gamma/LPS-activated macrophages there was a decreased amount and proportion of ferritin-bound iron and a compensatory increase in insoluble iron, which probably consists mainly of iron bound to intracellular organelles. Finally, although NO released by IFN-gamma/LPS-activated macrophages increased the iron-responsive element (IRE)-binding activity of both IRP1 and IRP2, IFN-gamma treatment decreased IRP2 activity in an NO-independent manner. This study demonstrates that the effect of IFN-gamma and/or LPS on macrophage iron metabolism is complex, and is not entirely due to either NO-or to IRP-mediated mechanisms. The overall effect is to decrease iron uptake, but not its utilization.
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PMID:Regulation of iron metabolism in murine J774 macrophages: role of nitric oxide-dependent and -independent pathways following activation with gamma interferon and lipopolysaccharide. 1049 10

Lactoferrin (LFR) plays an important role in the anti-microbial defense through iron binding, lipopolysaccharide binding and immunomodulation. In this study, we demonstrate that bovine LFR specifically inhibits the hemolytic activity of listeriolysin O (LLO) produced by Listeria monocytogenes. The hemolytic activity of LLO was completely inhibited in the presence of bovine LFR that was highly purified on two cation-exchange columns, whereas that of streptolysin O or perfringolysin O was not inhibited at all. A rabbit anti-LFR antibody canceled this inhibitory activity of bovine LFR. Although human transferrin exhibits 62% amino acid identity with bovine LFR, human apo-transferrin could not inhibit LLO-induced hemolysis. An increase in the concentration of FeCl3 or the Fe3+-saturation of bovine LFR, however, slightly reduced its inhibition of the hemolysis. The inhibitory activity of bovine LFR was dependent on pH, since it was observed under neutral and alkali conditions, but not under acidic conditions. These results suggest that the inhibition of LLO-induced hemolysis by bovine LFR is influenced by pH and iron ions, both of which may lead to conformational changes of LFR.
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PMID:Inhibition of listeriolysin O-induced hemolysis by bovine lactoferrin. 1059 21

Epidemiology studies have demonstrated increased pulmonary morbidity such as allergy and infection with episodes of high particulate air pollution (size range 0.1-10 microm diameter, PM10), but the mechanism(s) for this association is not yet well defined. The present study was undertaken to evaluate the effects of EHC-93 urban particles (Ottawa dust) on immune functions of peripheral blood mononuclear cells (PBMCs) and splenocytes from male Fischer 344 rats and C57Bl/6 mice. Immune function endpoints evaluated included cell viability, lymphocyte blastogenesis stimulated by T-cell mitogen (concanavalin A, Con A) or B-cell mitogens [lipopolysaccharide (LPS) or LPS/dextran sulfate], intracellular Ca2+ concentration, interleukin 2 (IL-2) production, and expression of receptors for transferrin (TfR) and IL-2 (IL-2R). In addition, the effect of N-acetylcysteine (NAC), an antioxidant, on the toxicity of EHC-93 particles was evaluated. Total EHC-93 particles, water leachate of EHC-93, and washed EHC-93 suppressed proliferation of PBMCs and splenocytes to T- and B-cell mitogens. Treatment of splenocytes with EHC-93 particles did not alter intracellular Ca2+ concentration or mitogen-induced expression of TfR and IL-2R expression, but increased IL-2 production assayed by enzyme-linked immunosorbent assay (ELISA). In spite of an increase in IL-2 production, exogenous IL-2 when added to cultures was able to reverse the suppression of Con A-induced lymphocyte proliferation by EHC-93 particles. Furthermore, the suppressive effect of EHC-93 particles on mitogen-induced lymphocyte proliferation was completely abolished by addition of the antioxidant NAC to cultures, suggesting a possible role of oxidative factors for the toxicity of EHC-93 particles.
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PMID:Suppression of rat and mouse lymphocyte function by urban air particulates (Ottawa dust) is reversed by N-acetylcysteine. 1065 36

Iron regulatory proteins (IRP-1 and IRP-2) control the synthesis of transferrin receptors (TfR) and ferritin by binding to iron-responsive elements, which are located in the 3'-untranslated region and the 5'-untranslated region of their respective mRNAs. Cellular iron levels affect binding of IRPs to iron-responsive elements and consequently expression of TfR and ferritin. Moreover, NO(*), a redox species of nitric oxide that interacts primarily with iron, can activate IRP-1 RNA binding activity resulting in an increase in TfR mRNA levels. Recently we found that treatment of RAW 264.7 cells (a murine macrophage cell line) with NO(+) (nitrosonium ion, which causes S-nitrosylation of thiol groups) resulted in a rapid decrease in RNA binding of IRP-2 followed by IRP-2 degradation, and these changes were associated with a decrease in TfR mRNA levels (Kim, S., and Ponka, P. (1999) J. Biol. Chem. 274, 33035-33042). In this study, we demonstrated that stimulation of RAW 264.7 cells with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) increased IRP-1 binding activity, whereas RNA binding of IRP-2 decreased and was followed by a degradation of this protein. Moreover, the decrease of IRP-2 binding/protein levels was associated with a decrease in TfR mRNA levels in LPS/IFN-gamma-treated cells, and these changes were prevented by inhibitors of inducible nitric oxide synthase. Furthermore, LPS/IFN-gamma-stimulated RAW 264.7 cells showed increased rates of ferritin synthesis. These results suggest that NO(+)-mediated degradation of IRP-2 plays a major role in iron metabolism during inflammation.
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PMID:Effects of interferon-gamma and lipopolysaccharide on macrophage iron metabolism are mediated by nitric oxide-induced degradation of iron regulatory protein 2. 1069 16


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