Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0243026 (sepsis)
 52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor-alpha (TNF alpha) and interleukin-1 alpha (IL-1 alpha) are pluripotent cytokines mediating the host response to sepsis, injury, and cancer. Animals can be protected from the lethal effects of TNF alpha by repeated administration of sublethal doses, but the mechanism of this effect is not known. Human foreskin fibroblasts (FS4 cells), which rapidly elaborate interleukin-6 (IL-6) when stimulated with TNF alpha or IL-1 alpha, were grown in culture as confluent monolayers and their secretion of IL-6 was quantitated using the murine B9-hybridoma bioassay against an external reference of human recombinant IL-6 (Genetics Institute). When FS4 cells were incubated with human recombinant TNF alpha (50 ng/ml; Cetus) or recombinant IL-1 alpha (30 pg/ml; Genzyme) a rapid increase in IL-6 production was measured over control, rising to IL-6 levels of 71.7 +/- 5.9 units/ml with TNF alpha and 54.0 +/- 1.2 units/ml with IL-1 alpha after 7.5 hr incubation. FS4 cells which were exposed to cytokine, rinsed, and then reexposed to cytokine 24 hr later produced significantly less IL-6 [38.1 +/- 2.8 units/ml with second exposure to TNF alpha (P less than 0.05), and 18.3 +/- 1.9 units/ml with second exposure to IL-1 alpha (P less than 0.01)]. Successive daily exposure to TNF alpha or IL-1 alpha caused a further stepwise diminution of IL-6 secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Decreased IL-6 secretion by fibroblasts following repeated doses of TNF alpha or IL-1 alpha: post-transcriptional gene regulation. 206 55

Tumor necrosis factor (TNF) released by lipopolysaccharide (LPS)-stimulated mononuclear phagocytes is a critical mediator of sepsis. We examined the capacities of rough mutant Salmonella typhimurium LPS (Rc) and LPS partial structures lipid A, monophosphoryl lipid A (MPLA), lipid IVA, and lipid X to induce production of TNF in whole blood. Rc LPS (0.0001-10 ng/ml) produced a dose-dependent release of TNF as determined by cytotoxicity of actinomycin D-sensitized L929 murine fibroblasts. Lipid A, MPLA, lipid IVA, and lipid X exhibited decreasing capacities to stimulate production of TNF in whole blood, respectively. Fractional deacylation of LPS by incubation with acyloxyacyl hydrolase isolated from human leukocytes produced a reduction in the capacity of LPS to induce TNF release in whole blood. Maximal enzymatic deacylation reduced activity of LPS by greater than 100-fold. Coincubation with lipid IVA inhibited TNF release induced by Rc LPS or lipid A, but not by phorbol ester. In contrast, MPLA, lipid X, and deacylated LPS failed to inhibit LPS-stimulated release of TNF. Corresponding to the inhibition of the release of TNF protein, lipid IVA also inhibited the accumulation of TNF mRNA in LPS-stimulated mononuclear cells. These results suggest that lipid IVA may act as a competitive antagonist of LPS, perhaps at the receptor level.
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PMID:Lipid IVA inhibits synthesis and release of tumor necrosis factor induced by lipopolysaccharide in human whole blood ex vivo. 219 1

Tumor necrosis factor, a mononuclear phagocyte-derived peptide produced in response to lipopolysaccharide, has been shown to mediate certain aspects of septic shock and multiple organ failure resulting from gram-negative septicemia. In the present investigation, pretreatment of animals with pentoxifylline inhibited lipopolysaccharide-induced serum tumor necrosis factor in a dose-dependent fashion. Pentoxifylline prevented the sequestration of neutrophils seen in animals given intravenous lipopolysaccharide. Furthermore, pentoxifylline protected animals from the lethal effects of an intravenous challenge with lipopolysaccharide. These data indicate that pentoxifylline inhibits lipopolysaccharide-induced tumor necrosis factor and may be an effective agent in mitigating the lethal consequences of sepsis and other disease processes mediated by this cytokine.
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PMID:Pentoxifylline inhibits lipopolysaccharide-induced serum tumor necrosis factor and mortality. 223 23

Tumor necrosis factor (TNF), a polypeptide produced predominantly by activated macrophages, is an important mediator of sepsis. We analyzed the specific metabolic changes that occur in the gut following TNF administration. Following general anesthesia, hemodynamic and metabolic indices were measured serially in control dogs (n = 7) and animals receiving a continuous sublethal intravenous infusion of TNF (0.57.10(5) IU/kg/6 hours, n = 7). During TNF infusion mean arterial pressure gradually decreased despite fluid administration, which maintained wedge pressure and cardiac index, which were similar to control animals. While TNF significantly reduced intestinal blood flow to 12 +/- 3 mL/min/kg compared to 28 +/- 3 mL/min/kg (p less than 0.01) in controls, intestinal oxygen consumption was maintained due to an increased extraction rate. Despite hypoperfusion the intestinal exchange of metabolic substrate (glucose, lactate, pyruvate, alanine, glutamine, glutamate, and ammonia) was comparable between the control and TNF-infused animals. However, when substrate carbon balance across the intestinal tract was calculated, it appeared that there was a limitation in fuel availability in the TNF animals. This may be due to competition for fuel between the gut and other major organs. Fuel limitation may jeopardize rapid cell proliferation and mucosal repair and with regional hypoperfusion these processes may account for the mucosal ulcerations observed at the termination of the study.
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PMID:The effects of tumor necrosis factor on intestinal structure and metabolism. 225 57

Tumor necrosis factor (TNF) mRNA was detected by Northern blotting in whole-organ homogenates of the spleen, liver, kidney, lung, and small bowel in naive and saline-injected control rats, supporting the hypothesis that TNF mRNA is present in vivo in a preformed intracellular pool. TNF mRNA in endotoxin-treated rats as quantitated by densitometry of the ratio of TNF mRNA to actin mRNA in Northern blots was present in increased quantity in the liver, kidney, and lung (1.6-2.9 times over time zero levels) at 15 minutes and increased quantity in the spleen, liver, and kidney (1.3-1.9 times over time zero levels) at 30 minutes. The kinetics of endotoxin-induced TNF gene expression are consistent with the relatively transient peak of serum TNF protein levels reported by previous investigators to occur approximately 1 hour after injection of endotoxin. Because TNF mRNA appeared ubiquitous in the organs of control rats examined and because the endotoxin-induced increase in TNF mRNA was relatively small, endotoxin may induce the expression of the TNF protein in serum not only by increasing TNF mRNA levels but perhaps more importantly by a posttranscriptional mechanism. The presence of a preformed pool of TNF mRNA may teleologically be viewed as a mechanism to increase the rapidity of the host's response to sepsis.
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PMID:Endotoxin-induced cytokine gene expression in vivo. I. Expression of tumor necrosis factor mRNA in visceral organs under physiologic conditions and during endotoxemia. 264 83

Tumor necrosis factor (TNF) is a macrophage product released in response to endotoxin that has been implicated as a cause of the toxicity and lethality seen in septic shock. Previous work suggests that tolerance to nutritional and lethal effects of TNF occur after repeated exposure to recombinant tumor necrosis factor (rTNF). In this study pretreatment of rats with a single low intravenous dose of rTNF prevented subsequent death when a lethal dose of rTNF was administered 24 hours later (tolerance or tachyphylaxis). Pretreatment with rTNF also afforded protection against the lethal effects of either endotoxin or cecal ligation and puncture when rats were challenged 24 hours later. Recombinant TNF injected 6 hours after cecal ligation and puncture initially resulted in a significant survival advantage for treated animals. When this experiment was repeated with a different lot of rTNF, however, the therapeutic benefit of rTNF was not obtained until the dose was decreased by a factor of 10. Protection against the lethal effects of cecal ligation and puncture did not occur when rTNF was given 24 hours after the insult. A single low dose of rTNF can result in tolerance or tachyphylaxis to the lethal effects of TNF. The results suggest that the early administration of low-dose rTNF may be useful in the prevention and treatment of the lethality of sepsis.
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PMID:Prevention and treatment of endotoxin and sepsis lethality with recombinant human tumor necrosis factor. 266 93

Tumor necrosis factor (TNF) cachectin has been implicated as an important host mediator responsible for shock and multiple organ failure (MOF) observed during sepsis. Using a sensitive enzyme-linked immunosorbent assay, we measured plasma TNF levels in 43 septic patients suffering from a broad range of diseases. Measurements were taken on the day that sepsis was diagnosed. Eleven patients had detectable TNF plasma levels ranging from 10 to 100 pg/ml (TNF-positive group); in 32 patients circulating TNF could not be detected (TNF-negative group). The groups did not differ significantly as to age, underlying disease, percentage positive bacteremia and bacteriologic profile, sepsis score, and extent of MOF. Eight (73%) of 11 TNF-positive patients died from sepsis during ICU stay, vs. 11 (34%) of 32 TNF-negative patients (p less than .05). This study demonstrates that sepsis is accompanied by detectable circulating TNF in 25% of the cases, and for these patients mortality is twice that for comparable TNF-negative patients.
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PMID:Plasma tumor necrosis factor and mortality in critically ill septic patients. 272 Dec 8

Using an enzyme-linked immunosorbent assay, we measured plasma levels of tumor necrosis factor (TNF) in 38 patients who were treated with either antilipid A antibody or a placebo for presumed gram-negative bacteremia. Sixteen of the 38 patients had positive blood cultures: 14 with gram-negative rods and 2 with Streptococcus pneumoniae. Initial serum samples for TNF determinations were obtained within 2 to 72 hours (mean, 18.8 hours) after the onset of clinical signs of sepsis. Six (16%) of 38 patients had detectable TNF levels: 4 of 14 with positive blood cultures for gram-negative rods but only 2 of 22 with negative blood cultures (odds ratio, 4; 95% confidence limits, 0.5 and 24.3). Of the 6 patients, 4 had received the placebo and 2 had received the antibody. Tumor necrosis factor levels did not predict adult respiratory distress syndrome, shock, disseminated intravascular coagulation, renal failure, or mortality. The highest TNF levels (500 and 250 pg/mL) were observed in 2 patients with Enterobacter cloacae bacteremia who had received the placebo and antilipid A antibody, respectively. The other 2 patients with bacteremia and detectable TNF levels had positive blood cultures for Haemophilus influenzae (50 pg/mL) and Bacteroides fragilis (120 pg/mL), respectively. Despite negative blood cultures, the remaining 2 patients repeatedly had detectable TNF levels and a clinical picture consistent with gram-negative sepsis.
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PMID:Plasma tumor necrosis factor levels in patients with presumed sepsis. Results in those treated with antilipid A antibody vs placebo. 230 78

Tumor necrosis factor/cachectin (TNF) is a mediator of the septic shock state, which can modulate hemostatic properties of the vessel wall. The interaction of TNF with endothelium is not cytotoxic, rather it is receptor mediated and results in a change in receptor expression on the endothelial cell surface, enabling endothelium to actively promote coagulation. Anticoagulant mechanisms, including the protein C/protein S system and fibrinolysis are suppressed, whereas the initiation and propagation of procoagulant activity is enhanced. This unidirectional shift in vessel wall coagulant activity favoring clot formation could contribute to the coagulopathy associated with sepsis and indicates a mechanism through which the coagulation system serves as an integral part of the host response.
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PMID:Tumor necrosis factor/cachectin-induced modulation of endothelial cell hemostatic properties. 282

Tumor necrosis factor (TNF) has been implicated in the toxic manifestations of overwhelming bacterial infection and in the tissue wasting that often accompanies prolonged infections and malignancy. We have examined a possible role of TNF in the early metabolic alterations following acute tissue injury or sepsis. Recombinant human TNF stimulated rat liver amino acid uptake up to 5-fold in vivo and there was a concomitant increase in plasma glucagon. In vitro TNF had no direct effect on hepatocyte amino acid uptake, but it markedly enhanced the stimulation of amino acid transport by glucagon, without an alteration in binding of glucagon to hepatocytes. This permissive effect of TNF on glucagon action represents an interrelationship between the immune and endocrine systems, and it may help to explain the mechanism of hormonal regulation of both the anabolic and catabolic responses to acute injury.
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PMID:Modulation of endogenous hormone action by recombinant human tumor necrosis factor. 282 98


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