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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Rats established on a normal (20% protein) diet or a protein-deficient (3% protein) diet were given either a subcutaneous injection of turpentine (5 ml/kg), which induces formation of aseptic abscesses, or saline. Plasma samples were obtained at timed intervals (0-14 days) after the injection for determination of albumin, total protein, alpha 2-macroglobulin (a major acute-phase protein in the rat) and interleukin-6 concentrations. The magnitude and pattern of the acute-phase protein response was then compared with the local inflammatory reaction, assessed histologically, and with changes in the circulating concentration of interleukin-6, which is an important mediator of the acute-phase protein response. 2. After turpentine injection there was an early fall in the plasma albumin and total protein concentrations in both normal and protein-deficient rats. After 12 h the total protein concentration increased in both groups of animals reaching a peak at about 48 h, whereas the plasma albumin concentration continued to fall reaching a minimum at 48 h. The main alpha 2-macroglobulin response was delayed and attenuated in the protein-deficient rats (onset 9 versus 24 h, peak concentration 8.95 +/- 0.5 versus 5.33 +/- 0.75 g/l, P < 0.01, and area under the concentration-time curve 18.43 +/- 2.13 versus 7.96 +/- 1.48 g/l-1 days, P < 0.01, in the normal group and protein-deficient group, respectively). 3. The circulating interleukin-6 concentration showed a transient early rise at 1 h, and was followed by a larger more sustained peak at 6-48 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of aseptic abscesses in protein-deficient rats on the relationship between interleukin-6 and the acute-phase protein, alpha 2-macroglobulin. 128 54

T4-binding globulin (TBG) shares a high degree of homology with two serpin antiproteases, alpha 1-antichymotrypsin (ACT) and alpha 1-antitrypsin (AT), whose synthesis is increased during the acute phase phenomenon, which accompanies trauma, infections, and neoplasms. Interleukin-6 (IL-6) is believed to be the main effector of the acute phase response. When evaluated in human hepatoblastoma-derived (Hep G2) cells exposed to different doses of the recombinant human cytokine for variable time intervals, IL-6 caused a dose- and time-dependent decrease in the secretion of [35S]methionine-labeled TBG, transthyretin (TTR), and albumin. The secretion of ACT and AT was increased. These changes were not due to alterations in the secretory process, since the kinetics of secretion of newly synthesized proteins were not modified. IL-6 did, however, cause a decrease in the steady state levels of mRNA for TTR, TBG, and albumin and an increase in ACT and AT mRNAs. In addition, nuclear run-off assay demonstrated a decrease in the transcription of TTR, TBG, and albumin genes and an increased transcription of the ACT gene. Quantitation of the results showed that changes in the secretion of proteins, in steady state mRNA levels, and in gene transcription were superimposable for each protein, indicating that IL-6 exerts its effect on thyroid hormone-binding proteins mostly at the transcriptional level and that TTR is the thyroid hormone-binding protein showing the most pronounced negative regulation by IL-6. The opposite effect of IL-6 on TBG and the antiproteases, despite their structural homology, underscores gene divergence among these proteins.
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PMID:Effects of interleukin-6 on the expression of thyroid hormone-binding protein genes in cultured human hepatoblastoma-derived (Hep G2) cells. 132 58

Prior studies on the in vitro hepatic acute phase response have involved either hepatoma cell lines or conventional short-term cultures of primary hepatocytes. No data are available on the response of primary hepatocytes in stable long-term culture systems. In this study, the acute phase response of rat and human hepatocytes in a new long-term culture system was examined in response to interleukin-6 (IL-6), interleukin-1 beta (IL-1 beta), and tumor necrosis factor alpha (TNF-alpha). The cultured cells were sandwiched between two layers of collagen in a (double-gel) configuration which has been shown to preserve both hepatocyte function and morphology over prolonged periods of time. The stability of this culture configuration enabled us to investigate, for the first time, the temporal aspects of the response in addition to the effects of the mediators on protein secretion. Exposure of rat hepatocytes to IL-6 after culture for 16 days resulted in a 2-fold reduction of albumin secretion and a 15-fold increase in the secretion rates of fibrinogen and alpha 2-macroglobulin. In all instances, the peak response occurred at 48 h after IL-6 exposure, and all protein secretion rates returned to pretreatment values within 5 days posttreatment. Changes in the mRNA levels of these proteins in response to IL-6 corresponded with those changes seen with the secreted products, indicating pretranslational regulation. Administration of IL-1 beta to rat hepatocyte produced a similar decline of albumin secretion and a 5-fold increase of fibrinogen secretion, whereas alpha 2-macroglobulin secretion remained undisturbed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A stable long-term hepatocyte culture system for studies of physiologic processes: cytokine stimulation of the acute phase response in rat and human hepatocytes. 136 59

The kinetics of cytokine release and acute-phase protein gene expression in liver were investigated in rats receiving a single intraperitoneal bolus dose of Escherichia coli lipopolysaccharide (LPS). Transient elevation of plasma tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were detected. Hepatic messenger RNAs for two acute-phase proteins, alpha 1-acid glycoprotein and alpha 2-macroglobulin, were measured by Northern blotting and were found to increase to a maximum at 24 h, returning to normal by 72 h; plasma concentrations showed a slower but more sustained rise. For albumin, hepatic mRNA was reduced, being minimum at 24 h with a similar but more prolonged fall in plasma concentration. Pretreatment of rats with TNF-alpha monoclonal antibody 4 h before LPS ameliorated weight loss and anorexia, partially suppressed the rise in IL-6 and reduced the increase in hepatic mRNA and plasma concentrations of alpha 1-acid glycoprotein and alpha 2-macroglobulin. For albumin, however, such pretreatment had no effect on the fall in either hepatic mRNA or plasma concentration. Thus we have defined an in vivo role of TNF-alpha in the control of endotoxin-induced acute-phase protein generation.
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PMID:Kinetics of endotoxin-induced acute-phase protein gene expression and its modulation by TNF-alpha monoclonal antibody. 137 42

A randomised study was performed to evaluate the association between some commonly measured acute phase proteins and interleukin-6 after a standard musculoskeletal operation, and to investigate the effect of high doses of corticosteroids on these proteins. Eight men and four women with osteoarthrosis but who were otherwise healthy and who were each to have an uncemented hip prosthesis inserted by the porous coated anatomical technique, were included. Patients were randomised to receive methylprednisolone 30 mg/kg body weight 1 1/2 hours before, and four and 12 hours after, operation (n = 6) and compared to a control group (n = 6). Plasma concentrations of C reactive protein, haptoglobin, orosomucoid and alpha 1-antitrypsin; serum concentration of albumin; packed cell volume; white cell count; and plasma concentration of interleukin-6 were measured. The increases in concentrations of acute phase proteins in plasma were significantly less in the group given steroids, but this did not have any obvious clinical consequences. Increase in the concentration of interleukin-6 preceded the increases in acute phase proteins in both groups, reflecting the role of interleukin-6 in the regulation of expression of acute phase protein genes in hepatic cells. The increase of interleukin-6 in the group receiving steroids was less pronounced than that in the control group, indicating that corticosteroids inhibit the generation of interleukin-6 in vivo.
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PMID:Acute phase reactants and interleukin 6 after total hip replacement. Effects of high dose corticosteroids. 138 23

Cerebrospinal fluid (CSF) and serum samples of 20 patients with central nervous system manifestations of hematological malignancies including primary cerebral lymphoma (n = 5) and disseminated non-Hodgkin lymphoma (n = 7) were examined for albumin, IgG, IgM, fibronectin, beta 2-microglobulin, interleukin-6, soluble interleukin-2 receptor, tumor necrosis factor alpha, and oligoclonal immunoglobulin bands. Although a broad range of abnormalities were detected, no reliable CSF parameter for the diagnosis of leptomeningeal spread from hematological neoplasias could be identified. An analysis of 61 repeat lumbar punctures added little to the findings of the first CSF examinations. Currently, immunochemical studies of CSF cell surface markers and early biopsy have probably more clinical value than the determination of the humoral CSF parameters included in this study. However, analysis of cytokine synthesis by single CSF cells using molecular biology techniques may improve the differential diagnosis of hematological neoplasia of the brain and spinal cord in the future.
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PMID:Humoral CSF parameters in the differential diagnosis of hematologic CNS neoplasia. 141 21

Hepatocyte growth factor (HGF), a potent mitogen for mature hepatocytes, has been considered to act as a hepatotropic factor for liver regeneration. We examined the effect of HGF on albumin synthesis and DNA synthesis of adult rat hepatocytes cultured at various cell densities. HGF stimulated albumin synthesis of hepatocytes by 40-60% when they were cultured at higher cell densities such that there was tight cell-cell contact. But at lower cell densities HGF failed to stimulate albumin synthesis. In contrast, the stimulatory effect of HGF on DNA synthesis of hepatocytes was more potent at lower than at higher cell densities: HGF did not stimulate DNA synthesis of hepatocytes cultured at confluent cell density. Thus, HGF seems to stimulate both albumin synthesis and DNA synthesis of hepatocytes, in a reciprocal relationship depending on cell density. When the effects of various cytokines were examined, epidermal growth factor, transforming growth factor-alpha, and acidic fibroblast growth factor also stimulated albumin synthesis by 20-30%. However, transforming growth factor-beta 1, basic fibroblast growth factor, and interleukin-1 beta had no effect on albumin synthesis, while interleukin-6 inhibited it by 42%. Thus HGF was the most potent in stimulating albumin synthesis in these cytokines. Since HGF is markedly increased in the liver or plasma following various liver insults, HGF may be involved in liver regeneration through the potential to stimulate both cell growth and liver-specific functions such as albumin synthesis in a cell density-dependent manner.
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PMID:Cell density-dependent regulation of albumin synthesis and DNA synthesis in rat hepatocytes by hepatocyte growth factor. 142 19

Due to the stress imposed by the process of bone marrow transplantation (BMT), we hypothesized that individuals receiving such a transplant underwent an acute phase response (APR). Circulating levels of C-reactive protein (CRP), haptoglobin (HAP), alpha-1 acid glycoprotein (AAG), ceruloplasmin (CER), zinc (Zn), copper (Cu), interleukin-6 (IL-6), albumin (ALB), and thyroxine-binding prealbumin (TBPA), were measured at baseline (Day -7), Day -4, Day 0 (Transplant Day), Day +2, +7, and weekly until day 28 in 14 adults receiving an autologous bone marrow transplant as Phase 1 treatment for various hematologic or solid tumor malignancies. Ten of 14 recipients survived, 9 of which had a significant increase in CRP (p = 0.012), HAP (p = 0.011), AAG (p = 0.002), and decrease in ALB (p = 0.002) and TBPA (p = 0.004) on Day +7, but not Day 0, after bone marrow reinfusion. These findings document the presence of an APR and suggest that the bone marrow transplant process (post reinfusion) initiates a stress response in the recipient.
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PMID:The acute phase response in autologous bone marrow transplantation. 147 99

Decreased albumin synthesis by hepatocytes in liver injury is thought to occur in response to Kupffer cell-derived acute-phase cytokines. In this study we used hepatocytes maintained in a differentiated phenotype, by culture on a laminin-rich gel substratum (Engelbreth-Holm-Swarm matrix), to investigate the effects of Kupffer cell-conditioned medium and purified cytokines (interleukin-1, interleukin-6 and tumor necrosis factor-alpha) on albumin synthesis. Kupffer cell-conditioned medium caused a reversible decrease in albumin synthesis to 64.7% of control (p less than 0.01, Wilcoxon's rank sum test, n = 11) on day 2. Repeated doses caused further dose-dependent reversible responses. The same result was obtained when protease inhibitors (alpha 1-antitrypsin and alpha 2-macroglobulin) were added to Kupffer cell-conditioned medium (n = 3), thus eliminating the potential effect of matrix degradation. Pure interleukin-1, interleukin-6 and tumor necrosis factor-alpha also inhibited albumin synthesis (p less than 0.05, Wilcoxon's rank sum test, n = 5), interleukin-6 having the greatest effect. After exposure to interleukin-1 (30 U.ml-1) and tumor necrosis factor-alpha (300 U.ml-1), decreased albumin synthesis was followed by a rebound increase (n = 3). Our results support the hypothesis that reduced albumin synthesis in the acute-phase response is modulated by cytokines released from Kupffer cells. Moreover, our results suggest that hepatocytes may exhibit a compensatory increase in albumin synthesis after cytokine withdrawal. These findings may be of physiological importance in the recovery from injury and the acute-phase response in vivo.
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PMID:Reversible inhibition of albumin production by rat hepatocytes maintained on a laminin-rich gel (Engelbreth-Holm-Swarm) in response to secretory products of Kupffer cells and cytokines. 150 18

The biochemical nature of endogenous interleukin-6 (IL-6) as it exists in human serum or plasma was investigated. Serum from a patient following bone marrow (BM) transplantation and fresh plasma samples from patients with epidermolysis bullosa or psoriasis, as well as from normal volunteers, were fractionated through G-200 columns and each of the eluted fractions assayed for IL (interleukin)-6 content using enzyme-linked immunosorbent assays (ELISAs) based on the monoclonal antibody (mAb) pairs IG61/5IL6 or 4IL6/5IL6 and in the B9 hybridoma growth factor bioassay. The IG61/5IL6 ELISA and the B9 assay detected IL-6 in BM serum almost exclusively of molecular mass approximately 20 kDa. In contrast, the 4IL6/5IL6 ELISA detected strong IL-6 immunoreactivity in complexes of size 100-150 and 400-500 kDa. IL-6 present in the 100-150- and 400-500-kDa complexes was purified by immunoaffinity chromatography through a 5IL6 mAb column. The 5IL6 mAb immunoaffinity column eluate of the respective pools from BM serum contained IL-6 at concentrations approaching 1 microgram/ml as characterized by Western blotting. Sufficient IL-6 and associated proteins were purified by 5IL6 mAb immunoaffinity column chromatography of the 100-150-kDa complex from 0.8 ml of BM serum to allow (i) verification of three of the polypeptides as IL-6 by amino-terminal sequencing (estimate of IL-6 in original serum sample: 5-10 micrograms/ml), (ii) identification by amino acid sequencing of the "associated" proteins as complement factor C3b (carboxyl-terminal of the alpha-chain), complement factor C4b (gamma-chain), C-reactive protein, and albumin, and (iii) detection of an "associated" polypeptide consistent with the soluble IL-6 receptor. Taken together, these data establish that IL-6 is present at unexpectedly high concentrations in human blood in novel biochemical complexes that include other plasma proteins, which in turn, can camouflage IL-6 immunoreactivity and bioactivity as measured in conventional assays.
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PMID:High levels of "complexed" interleukin-6 in human blood. 152 89


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