Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxygen radicals have been implicated in the pathogenesis of acute lung injury associated with clinical and experimental sepsis. With the use of endotoxin infusion as an in vivo model of sepsis we studied the effect of recombinant-human superoxide dismutase (r-hSOD; 4,200 U/mg), an enzyme that catalyzes the dismutation of superoxide anion, on both the physiologic and biochemical lung changes in awake sheep. Sheep (n = 11) were prepared for chronic measurement of pulmonary hemodynamics and lung fluid balance. Paired experiments were performed in seven of the animals in which they received either endotoxin (1 microgram/kg) alone or in combination with r-hSOD in random order. An additional four sheep received r-hSOD without the lipopolysaccharide. Intravenous infusion of r-hSOD (a loading dose of 12,600 U/kg followed by a maintenance dose of 14,700 U/kg/h for 7 h) resulted in substantial SOD activity, measured by electron spin resonance spectrometry, both in plasma and in lung lymph, and attenuated the expected changes in pulmonary arterial pressure and lung lymph flow after administration of endotoxin. When administered without endotoxin, r-hSOD produced no perceptible change in pulmonary hemodynamics and lung fluid balance. These data suggest that superoxide anion plays an important role in endotoxin-induced lung injury in sheep.
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PMID:Recombinant-human superoxide dismutase attenuates endotoxin-induced lung injury in awake sheep. 131 93

Cyclooxygenase inhibition has been proposed as treatment for sepsis-induced acute lung injury. However, the mechanism of protection offered by the cyclooxygenase inhibitor ibuprofen is not well understood. To elucidate this mechanism, the effects of ibuprofen on the neutrophil respiratory burst and alveolar-capillary membrane leak were studied. Anesthetized swine (15 to 25 kg) were intubated and mechanically ventilated (fraction of inspired oxygen, 0.5). Control animals (n = 5) received a sham infusion of 0.9% NaCl, animals with sepsis (n = 10) received a 1-hour infusion of live Pseudomonas aeruginosa (5 x 10(8) colony-forming units/ml at 0.3 ml/20 kg/hr), and treated animals (ibuprofen-treated control animals [n = 4] or ibuprofen-treated animals with sepsis [n = 9]) received ibuprofen (12.5 mg/kg at 0 and 120 minutes). All animals were studied for 300 minutes. Neutrophils were isolated at 0, 60, and 300 minutes. Neutrophil superoxide anion production (O2-) was assessed in a kinetic fashion (in nanomoles per minute) by superoxide dismutase-inhibitable cytochrome C reduction (phorbol myristate acetate stimulation). Bronchoalveolar lavage protein estimation (0 and 300 minutes) and extravascular lung water (double indicator dilution) were performed to assess alveolar-capillary membrane leak. Ibuprofen significantly attenuated sepsis-enhanced maximum neutrophil generation of O2- (6.0 +/- 0.5 nmol/min for animals with sepsis, 300 minutes, vs 4.1 +/- 0.5 nmol/min for ibuprofen-treated animals, with sepsis, 300 minutes; p less than 0.05), indicating an in vivo down-regulatory effect on neutrophil oxidant generation. Ibuprofen also prevented increased airspace bronchoalveolar lavage protein and extravascular lung water accumulation, suggesting a protective effect on the alveolar-capillary membrane. This protective effect of ibuprofen in acute lung injury may be through a decreased neutrophil respiratory burst.
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PMID:The neutrophil respiratory burst and tissue injury in septic acute lung injury: the effect of cyclooxygenase inhibition in swine. 132 Feb 99

Peroxynitrite (ONOO-), the reaction product of superoxide (O2-) and nitric oxide (NO), may be a major cytotoxic agent produced during inflammation, sepsis, and ischemia/reperfusion. Bovine Cu,Zn superoxide dismutase reacted with peroxynitrite to form a stable yellow protein-bound adduct identified as nitrotyrosine. The uv-visible spectrum of the peroxynitrite-modified superoxide dismutase was highly pH dependent, exhibiting a peak at 438 nm at alkaline pH that shifts to 356 nm at acidic pH. An equivalent uv-visible spectrum was obtained by Cu,Zn superoxide dismutase treated with tetranitromethane. The Raman spectrum of authentic nitrotyrosine was contained in the spectrum of peroxynitrite-modified Cu,Zn superoxide dismutase. The reaction was specific for peroxynitrite because no significant amounts of nitrotyrosine were formed with nitric oxide (NO), nitrogen dioxide (NO2), nitrite (NO2-), or nitrate (NO3-). Removal of the copper from the Cu,Zn superoxide dismutase prevented formation of nitrotyrosine by peroxynitrite. The mechanism appears to involve peroxynitrite initially reacting with the active site copper to form an intermediate with the reactivity of nitronium ion (NO2+), which then nitrates tyrosine on a second molecule of superoxide dismutase. In the absence of exogenous phenolics, the rate of nitration of tyrosine followed second-order kinetics with respect to Cu,Zn superoxide dismutase concentration, proceeding at a rate of 1.0 +/- 0.1 M-1.s-1. Peroxynitrite-mediated nitration of tyrosine was also observed with the Mn and Fe superoxide dismutases as well as other copper-containing proteins.
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PMID:Peroxynitrite-mediated tyrosine nitration catalyzed by superoxide dismutase. 141 74

The placement of rubber band tourniquets upon rat hind-limbs for 5 h followed by reperfusion of the extremities results in a severe form of circulatory shock characterized by hypotension and death within 24 h of tourniquet release. Oxidative damage to muscle tissue is an early consequence of hind-limb reperfusion on tourniquet release, yet this local damage does not explain the lethal hypotensive shock state which evolves within the next 24 h. Multiple system organ failure (MSOF), of as of yet unknown causes, is usually described in relation to several shock states. It has been suggested that injured or necrotic tissue may activate neutrophils, platelets, and the coagulation system leading to embolization in remote tissues. Effective decreases in hepatic blood flow have been observed in several forms of sepsis which precedes the biochemical evidence consistent with an ischemic insult of the liver. In support of our original hypothesis, that organ failure has its genesis in a primary perfusion abnormality with secondary ischemic organ injury, herein we have assessed the possibility that oxygen-derived free radicals are generated in the liver of rats after reperfusion of their hind-limbs on release of the tourniquets. We report on the protective effects of allopurinol (ALLO) and a mixture of superoxide dismutase (SOD) catalase (CAT) and dimethylsulfoxide (DMSO) on liver free sulfhydryl content (SH), thiobarbituric acid-reactive substances (TBARS), and on the release of aspartic acid (AsT) and alanine aminotransferase (AlT) activities, and of alkaline phosphatase during a 5 h tourniquet period and after 2 h of reperfusion of the hind-limbs. During the hind-limb ischemic period hepatis tissue SH levels remained essentially constant during the first hour (6.02 +/- 0.36 to 5.65 +/- 0.20 mumoles/g wet tissue), and decreased significantly, over and above the normal circadian decrease of liver glutathione levels, to 4.02 +/- 0.69 mumoles/g wet tissue after the third hour and remained lowered until tourniquet release. A further significant decrease (3.11 +/- 0.49 mumoles/g wet tissue) was observed after 2h of reperfusion. TBARS production remained constant during the 5 h hind-limb ischemic period (168.4 +/- 37.3 mumoles/g wet tissue) and rose by 55% to 261.7 +/- 55.8 mumoles/g wet tissue after 2 h of tourniquet release. ALLO, but not the SOD-CAT-DMSO combination, protected hepatic SH loss during the hind-limb ischemic insult, yet both offered protection after 2 h of tourniquet release.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Oxygen-derived free radicals mediate liver damage in rats subjected to tourniquet shock. 148 82

Tumor necrosis factor (TNF), a macrophage product released in response to endotoxin and other stimuli, has been shown to be a central mediator of endotoxin or septic shock. However, its highly conserved and wide-ranging physiological effects suggest that it may also be an essential cytokine in the host defense against acute bacterial infection or sepsis. A single nontoxic dose of human recombinant TNF administered intravenously 24 h prior to a lethal infusion of Escherichia coli lipopolysaccharide (LPS) completely prevented acute LPS-induced hypotension, ameliorated tissue injury in the lungs and liver, and improved survival in male Fisher 344 rats. The protective effects of TNF were dose dependent and required a 24-h pretreatment interval. After the infusion of LPS, animals in both groups (TNF-treated animals and saline-pretreated controls) initially appeared acutely ill and had a similar severe metabolic acidosis, indicating that TNF did not inactivate or prevent the toxic effects of LPS. Twelve hours after the administration of TNF, the gene for manganous superoxide dismutase, a mitochondrial enzyme which scavenges toxic reactive oxygen species and is induced during conditions which generate a free radical stress, was expressed in liver tissue, suggesting that the induction of manganous superoxide dismutase may be an important in vivo protective mechanism against cellular injury during lethal endotoxemia.
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PMID:Single-dose tumor necrosis factor protection against endotoxin-induced shock and tissue injury in rats. 193 48

Tumor necrosis factor (TNF) facilitates superoxide production, and spin traps may detoxify superoxide by acting as superoxide dismutase mimics. We investigated the ability of a stable nitroxide spin trap, TEMPOL, to protect TNF-sensitive cells from exogenously added TNF. WEHI or L929 cells were incubated with TNF (500 units/ml) for 18 hr either simultaneously with 0 to 8 mM TEMPOL or with the TEMPOL added at varying intervals after TNF exposure. A dose-dependent increase in survival was noted in the TEMPOL-treated cells, with 92 +/- 2% survival of WEHIs treated with 4 mM TEMPOL compared to 26 +/- 1% survival for non-TEMPOL-exposed cells (P2 less than 0.01). Significant increases in survival could be accomplished with as late as 15-hr delayed addition of the compound. The mechanism of protection does not seem to involve newly synthesized protein, and Northern blot analysis revealed that TEMPOL does not induce the genes for MnSOD or Cu-ZnSOD. The ability of TEMPOL to protect against TNF injury, even when exposure is delayed, may prove useful in conditions thought to be associated with free radical-lymphokine interactions such as ischemia-reperfusion, oxygen toxicity, or sepsis.
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PMID:Spin trap protection from tumor necrosis factor cytotoxicity. 203 86

Tumor necrosis factor (TNF) is a peptide secreted by macrophages in response to endotoxin that can produce many of the changes seen in septic shock. After cecal ligation and puncture (CLP) rats gradually develop tachycardia, hypotension, tachypnea, and hypothermia. At 5 h post-CLP, rats have a peak in serum levels of endotoxin and 60% of rats have blood cultures that grow Gram-negative rods (Escherichia coli and Klebsiella pneumonia). At 20 h post-CLP all rats develop positive blood cultures. Serum levels of TNF are not reproducibly measurable in rats following CLP. Rats undergoing CLP have a 50-80% mortality with deaths usually occurring 24-72 h postinjury. Repetitive (twice daily x 6 d) i.p. injection of sublethal doses of recombinant human TNF-alpha (100 micrograms/kg) to rats undergoing CLP 1 d after the treatment period resulted in a significant reduction in mortality compared to control rats previously unexposed to rTNF (P less than 0.03). Animals treated with rTNF had no hypotension or hypothermia after CLP and regained normal food intake faster than control rats. 12 h after CLP the gene expression for manganous superoxide dismutase (MnSOD), an inducible mitochondrial metalloenzyme responsible for cellular resistance to injury from toxic reactive oxygen species, was higher in livers of rats treated with rTNF suggesting that the TNF treatment augmented expression of this protective enzyme. Unlike MnSOD, expression of the gene for copper-zinc SOD was not affected by CLP or rTNF treatment. The results suggest that prior treatment with recombinant TNF can ameliorate the lethality, hypotension, hypothermia, and anorexia of Gram-negative sepsis in rats and that the mechanism may be related to enhanced hepatic expression of the gene for MnSOD. Repeated administration of recombinant TNF may be a strategy to minimize mortality and morbidity of Gram-negative sepsis.
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PMID:Treatment with recombinant human tumor necrosis factor-alpha protects rats against the lethality, hypotension, and hypothermia of gram-negative sepsis. 205 27

Live E. coli were infused i.v. in cats to induce gastrointestinal mucosal injury and the gastric mucosa was exposed to bile and a luminal pH of 1. A gastric lesion index was calculated and intestinal injury was graded. The effects of i.v. methylprednisolone before and after induction of bacteremia were compared with those of intragastric misoprostol combined with i.v. superoxide dismutase (SOD) and catalase and with a control group. Methylprednisolone, but not misoprostol/SOD/catalase, significantly reduced the gastric lesion index (p less than 0.05). The duodenum/small intestine was significantly injured in 4/6, 2/6 and 4/6 cats in the misoprostol/SOD/catalase, methylprednisolone and control groups, respectively (NS). End gastric luminal pH was 3.9, 2.7 and 4.5 in the respective groups (p less than 0.05), with systemic arterial pH 7.15, 7.15 and 7.32 (NS). Mean arterial pressure and cardiac output were improved with methylprednisolone. Misoprostol/SOD/catalase reduced late hypotension. Pulmonary arterial pressure rose to c. 200% of basal in all groups. Methylprednisolone, but not misoprostol/SOD/catalase, thus protected the gastric mucosa from sepsis-induced gastric injury concomitant with reduced disappearance of protons from the gastric lumen, but did not significantly affect small-bowel damage. Hemodynamic responses were significantly improved in methylprednisolone-pretreated cats.
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PMID:Feline E. coli bacteremia--effects of misoprostol/scavengers or methylprednisolone on hemodynamic reactions and gastrointestinal mucosal injury. 211 Jul 10

Oxygen-derived free radicals have been implicated as mediators of cellular injury in several model systems. In order to clarify the role of oxygen radicals in endotoxemia, we measured the serial lipid peroxide changes resulting from systemic radical reactions using a newly developed colormetric method. To determine the effect of a free radical scavenger on mortality in endotoxemia, a new synthetic scavenger, 2-Octadecylascorbic acid (CV-3611), which overcome the detrimental properties (circulation half-life and cell penetration) of native SOD, was used in the model of mouse endotoxemia induced by the i.p. administration of E-coli endotoxin (10 mg/kg). Serial LPO (Lipid Peroxide) changes revealed significant elevations from the basal level of 4.52 +/- 0.79 nmol/ml to 10.5 +/- 2.04 nmol/ml at 2h (P less than 0.05), 12.0 +/- 2.44 nmol/ml at 8h (P less than 0.05), 32.8 +/- 12.5 nmol/ml at 12h (P less than 0.05) and 13.6 +/- 2.40 nmol/ml at 24h (P less than 0.05) following i.p. administration of E-coli. The circulation half life of CV-3611 was checked by a reversed-phase HPLC after 10 mg/kg s.c. administration. The level of CV-3611 reached peak levels of 0.54 +/- 0.10 micrograms/ml at 1h and 0.52 +/- 0.20 micrograms/ml at 2h then gradually decreased to the level of 0.04 +/- 0.004 micrograms/ml at 6h and to a non-detectable level at 24h after s.c. administration. Increased survival was seen at 2 days (P less than 0.001) after E-coli endotoxin administration in the CV-3611 treated group compared to the control group. These results suggest that oxygen derived free radicals contribute to mortality in mouse endotoxemia and that antioxidants such as CV-3611 may provide a new therapeutic avenue by improving survival of patients with gram-negative bacterial sepsis.
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PMID:Effect of a new synthetic free radical scavenger, 2-octadecyl ascorbic acid, on the mortality in mouse endotoxemia. 226 76

In patients with septicemia and septic shock the contact phase of blood coagulation is activated. It has been suggested that polymorphonuclear leukocytes (PMN) are directly activated by purified plasma kallikrein. This has been recently questioned because granulocytic elastase release induced by recalcification of normal and prekallikrein-deficient plasma was similar. We studied the interaction of different preparations of purified human plasma kallikrein with PMN. Cytosolic calcium shifts were measured with the quin2 method, PMN aggregation was assayed in an aggregometer, and superoxide production was quantitated as superoxide dismutase inhibitable cytochrome c reduction in a continuous assay. No increase of cytosolic free calcium was found during at least 5 min after adding 10 micrograms/ml plasma kallikrein to PMN. Similarly, highly purified plasma kallikrein from two different sources did not induce PMN aggregation at all, nor did it stimulate superoxide production. However, sequential exposure of PMN to plasma kallikrein and formylpeptide increased the superoxide production compared to stimulation with formylpeptide alone. This phenomenon which is called priming was observed at plasma kallikrein concentrations greater than or equal to 7 micrograms/ml. The active site of the molecule was required for the priming, because plasma prekallikrein, active site-inactivated plasma kallikrein, and soybean trypsin inhibitor treated kallikrein did not prime PMN. This indicates that the contact activation system may play a role in host defence against bacterial infection.
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PMID:Purified human plasma kallikrein does not stimulate but primes neutrophils for superoxide production. 255 88


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