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Query: UMLS:C0243026 (sepsis)
 52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infection is a major complication of patients with diabetes, and endotoxemic shock is a serious complication during sepsis. The purpose of this study was to determine whether the action of bacterial lipopolysaccharide (LPS) on vasocontractility is altered in diabetic vessels. Diabetes was induced in 10-week-old Wistar rats by an intraperitoneal injection of streptozotocin. LPS-induced increase in cGMP (cyclic guanosine 3',5'-monophosphate) level was lower in aortae from streptozotocin-induced hyperglycemic (diabetic) rats than in those from vehicle-injected control rats, while LPS-induced nitric oxide production was not different in the diabetic and control aortae. Phenylephrine-induced contraction of diabetic aortae was lower than that of the control aortae. LPS treatment resulted in depression of contractile response to phenylephrine in both diabetic and control aortae, and the degree of depression was much lower in diabetic aortae. Treatment with N monomethyl l-arginine (l-NMMA) prevented diminution of phenylephrine-induced contraction of the aortae after LPS stimulation, and the degree of the preventive effect by l-NMMA was significantly lower in diabetic aortae than in the control aortae. Protein expression of inducible nitric oxide synthase detected by Western blot analysis was not different in the diabetic and control aortae. The decrease in cGMP production after LPS stimulation in diabetic aortae was not prevented by treatment of the aortae with superoxide dismutase but was partially prevented by that with Tiron (4,5-dihydroxy-1,3-benzene disulfonic acid), a cell-permeable scavenger of reactive oxygen species. These results suggest that LPS-induced depression of vasocontractility is attenuated in diabetic aortae due to a decrease in nitric oxide-stimulated cGMP production, probably resulting from increased inactivation of inducible nitric oxide by excessive intracellular oxidative stress. It is concluded that contractility of aortae from streptozotocin-induced hyperglycemic rats may be less affected by LPS during endotoxemia.
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PMID:Decreased modulation by lipopolysaccharide of aortic smooth muscle contractility in streptozotocin-induced hyperglycemic rats. 1254 75

Acute renal failure (ARF) during sepsis is associated with increased nitric oxide (NO) and oxygen radicals, including superoxide (O(2)(-)). Because O(2)(-) reacts with NO in a rapid manner, it plays an important role in modulating NO levels. Therefore, scavenging of O(2)(-) by superoxide dismutase (SOD) may be critical for preserving NO bioavailability. In mice, substantial renal extracellular SOD (EC-SOD) expression implies its important role in scavenging O(2)(-) in the kidney. We hypothesized that during endotoxemic ARF, EC-SOD is decreased in the kidney, resulting in increased O(2)(-) and thus decreased vascular NO bioavailability with resultant renal vasoconstriction and ARF. In the present study, normotensive endotoxemic ARF was induced in mice using lipopolysaccharide (LPS; 5 mg/kg ip). Sixteen hours after LPS, glomerular filtration rate (GFR; 50 +/- 16 vs. 229 +/- 21 microl/min, n = 8, P < 0.01) and renal blood flow (RBF; 0.61 +/- 0.10 vs. 0.86 +/- 0.05 ml/min, n = 8, P < 0.05) were subsequently decreased. EC-SOD mRNA and protein expression in endotoxemic kidneys were decreased at 16 h compared with controls. A catalytic antioxidant, metalloporphyrin, reversed the deleterious effects of endotoxemia on renal function as GFR (182 +/- 40 vs. 50 +/- 16 microl/min, n = 6, P < 0.01) and RBF (1.08 +/- 0.10 vs. 0.61 +/- 0.10 ml/min, n = 6, P < 0.05) were preserved. Similar results were obtained with tempol, a chemically dissimilar antioxidant. Specific inhibition of inducible nitric oxide synthase (iNOS), l-N(6)-(1-iminoethyl)-lysine, reversed the renal protective effect on GFR and RBF observed with antioxidant treatment during endotoxemia. In summary, renal EC-SOD expression is decreased during endotoxemia. Antioxidant therapy preserved GFR and RBF during endotoxemia. The reversal of this protective effect by inhibition of iNOS suggests the importance of the bioavailability of NO for preservation of renal function during early endotoxemia.
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PMID:Interaction among nitric oxide, reactive oxygen species, and antioxidants during endotoxemia-related acute renal failure. 1255 64

Obstructive jaundice is associated with high morbidity and mortality. Major complications such as pulmonary dysfunction, renal failure and sepsis are frequently encountered. Recent studies and observations suggest that the free oxygen radicals (FORs) produced in obstructive jaundice may play a significant role in the etiopathogenesis of acute renal failure (ARF). Thirty rats were divided into three groups, as sham, control and treatment groups containing 10 rats each. Laparatomy was performed on each animal in the control and treatment groups and common bile ducts were ligated. Common bile duct was observed but was not ligated for the rats in the sham group. Saline solution injection was begun on the first day of surgical procedure and repeated once a day during the following 5 days. The same procedure was performed with oxygen radical scavenger dimethyl sulfoxide (1.5 mg/kg/day i.p.) instead of saline in the treatment group. The rats were sacrificed on the 7th postoperative day. On the 7th postoperative day, the bilirubin, urea and creatinine levels of the control and treatment groups were significantly higher in comparison with the sham group (p < 0.01). Although there was no statistically significant difference between the bilirubin levels of the control and treatment groups (p > 0.05), the urea and creatinine levels in the treatment group were significantly lower (p < 0.01). On the 7th postoperative day, the erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels of the control and treatment groups were significantly lower than those of the sham group (p < 0.01), whereas renal and erythrocyte malondialdehyde (MDA) levels were significantly higher (p < 0.01). Although SOD and GSH-Px levels did not differ significantly between the treatment and control groups (p > 0.05), renal and erythrocyte MDA levels of the treatment group were significantly lower than those of the control group (p < 0.01). The histopathological scores were significantly higher in the control and treatment groups (p < 0.01); there was no significant difference between the control and treatment groups (p > 0.05). FORs seem to play a significant role in the etiopathogenesis of renal failure in obstructive jaundice. Antioxidant treatment may decrease oxidative damage due to FORs and may prevent renal failure.
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PMID:Role of oxygen free radical scavengers in acute renal failure complicating obstructive jaundice. 1274 May 34

Burn trauma produces significant fluid shifts that, in turn, reduce cardiac output and tissue perfusion. Treatment approaches to major burn injury include administration of crystalloid solutions to correct hypovolemia and to restore peripheral perfusion. While this aggressive postburn volume replacement increases oxygen delivery to previously ischemic tissue, this restoration of oxygen delivery is thought to initiate a series of deleterious events that exacerbate ischemia-related tissue injury. While persistent hypoperfusion after burn trauma would produce cell death, volume resuscitation may exacerbate the tissue injury that occurred during low flow state. It is clear that after burn trauma, tissue adenosine triphosphate (ATP) levels gradually fall, and increased adenosine monophosphate (AMP) is converted to hypoxanthine, providing substrate for xanthine oxidase. These complicated reactions produce hydrogen peroxide and superoxide, clearly recognized deleterious free radicals. In addition to xanthine oxidase related free radical generation in burn trauma, adherent-activated neutrophils produce additional free radicals. Enhanced free radical production is paralleled by impaired antioxidant mechanisms; as indicated by burn-related decreases in superoxide dismutase, catalase, glutathione, alpha tocopherol, and ascorbic acid levels. Burn related upregulation of inducible nitric oxide synthase (iNOS) may produce peripheral vasodilatation, upregulate the transcription factor nuclear factor kappa B (NF-kappaB), and promote transcription and translation of numerous inflammatory cytokines. NO may also interact with the superoxide radical to yield peroxynitrite, a highly reactive mediator of tissue injury. Free radical mediated cell injury has been supported by postburn increases in systemic and tissue levels of lipid peroxidation products such as conjugated dienes, thiobarbituric acid reaction products, or malondialdehyde (MDA) levels. Antioxidant therapy in burn therapy (ascorbic acid, glutathione, N-acetyl-L-cysteine, or vitamins A, E, and C alone or in combination) have been shown to reduce burn and burn/sepsis mediated mortality, to attenuate changes in cellular energetics, to protect microvascular circulation, reduce tissue lipid peroxidation, improve cardiac output, and to reduce the volume of required fluid resuscitation. Antioxidant vitamin therapy with fluid resuscitation has also been shown to prevent burn related cardiac NF-kappaB nuclear migration, to inhibit cardiomyocyte secretion of TNF-alpha, IL-1beta, and IL-6, and to improve cardiac contractile function. These data collectively support the hypothesis that cellular oxidative stress is a critical step in burn-mediated injury, and suggest that antioxidant strategies designed to either inhibit free radical formation or to scavage free radicals may provide organ protection in patients with burn injury.
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PMID:Free radicals and lipid peroxidation mediated injury in burn trauma: the role of antioxidant therapy. 1282 Dec 84

Skeletal muscle disuse with space-flight and ground-based models (e.g., hindlimb unloading) results in dramatic skeletal muscle atrophy and weakness. Pathological conditions that cause muscle wasting (i.e., heart failure, muscular dystrophy, sepsis, COPD, cancer) are characterized by elevated "oxidative stress," where antioxidant defenses are overwhelmed by oxidant production. However, the existence, cellular mechanisms, and ramifications of oxidative stress in skeletal muscle subjected to hindlimb unloading are poorly understood. Thus we examined the effects of hindlimb unloading on hindlimb muscle antioxidant enzymes (e.g., superoxide dismutase, catalase, glutathione peroxidase), nonenzymatic antioxidant scavenging capacity (ASC), total hydroperoxides, and dichlorohydrofluorescein diacetate (DCFH-DA) oxidation, a direct indicator of oxidative stress. Twelve 6 month old Sprague Dawley rats were divided into two groups: 28 d of hindlimb unloading (n = 6) and controls (n = 6). Hindlimb unloading resulted in a small decrease in Mn-superoxide dismutase activity (10.1%) in the soleus muscle, while Cu,Zn-superoxide dismutase increased 71.2%. In contrast, catalase and glutathione peroxidase, antioxidant enzymes that remove hydroperoxides, were significantly reduced in the soleus with hindlimb unloading by 54.5 and 16.1%, respectively. Hindlimb unloading also significantly reduced ASC. Hindlimb unloading increased soleus lipid hydroperoxide levels by 21.6% and hindlimb muscle DCFH-DA oxidation by 162.1%. These results indicate that hindlimb unloading results in a disruption of antioxidant status, elevation of hydroperoxides, and an increase in oxidative stress.
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PMID:Hindlimb unloading increases oxidative stress and disrupts antioxidant capacity in skeletal muscle. 1282 51

A new type adsorbent for removal of bacterial endotoxins was prepared by immobilizing lysine covalently onto cellulose beads. Endotoxins (Escherichia coli O55: B5) were injected into 13 healthy New Zealand white rabbits to induce infectious symptoms. Hemoperfusion using the adsorbent column removed endotoxins in the blood of eight rabbits during 2h while other five rabbits were used as control. The mean blood endotoxin concentration was reduced significantly from 5.56 +/- 0.54 EU/ml (1 EU = 100 pg) before treatment to 0.41 +/- 0.26 EU/ml after perfusion as measured by the limulus amebocyte lysate test (Chromogenix). Liver function and renal function tests showed significant improvement of septic symptoms in contrast to the control group. Other parameters such as superoxide dismutase and malondialdehyde were ameliorated markedly after the treatment. Moreover, the adsorbent showed good results in mechanical strength, blood compatibility and cytotoxicity, which suggested that lysine-cellulose adsorbent was of high ET-binding efficacy without significant side effect. It has a high potential of clinical application for treatment of patients with severe sepsis.
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PMID:In vivo studies of endotoxin removal by lysine-cellulose adsorbents. 1513 Jul 28

Previous analysis showed that selective inhibitors of five different host inflammatory mediators administered for sepsis, although beneficial with severe sepsis and high-control mortality rates, were ineffective or harmful with less severe sepsis. We hypothesized that severity of sepsis would also influence inhibition of superoxide anion, another inflammatory mediator. To test this, 6-h infusions of M40401, a selective SOD mimetic, or placebo were given to antibiotic-treated rats (n=547) starting 3 h after challenge with differing doses of intravenous Escherichia coli designed to produce low- or high-control mortality rates. There was a positive and significant (P=0.0008) relationship between the efficacy of M40401 on survival rate and control mortality rates. M40401 increased or decreased the log (odds ratio of survival) (means +/- SE), dependent on whether control mortality rates were greater or less than the median (66%) (+0.19 +/- 0.12 vs. -0.25 +/- 0.10, P=0.01). In a subset of animals examined (n=152) at 9 h after E. coli challenge, M40401 increased (mean effect +/- SE compared with control) mean arterial blood pressure (8 +/- 5 mmHg) and decreased platelets (-37 +/- 22 cells x 10(3)/ml) with high-control mortality rates but had opposing effects on each parameter (-3 +/- 3 mmHg and 28 +/- 19 cells x 10(3)/ml, respectively) with low rates (P < or = 0.05 for the differing effects of M40401 on each parameter with high- vs. low-control mortality rates). A metaregression analysis of published preclinical sepsis studies testing SOD preparations and SOD mimetics showed that most (16 of 18) had control mortality rates >66%. However, across experiments from published studies, these agents were less beneficial as control mortality rate decreased (P=0.03) in a relationship not altered (P=not significant) by other variables associated with septic challenge or regimen of treatment and which was similar, compared with experiments with M40401 (P=not significant). Thus, in these preclinical sepsis models, possibly related to divergent effects on vascular function, inhibition of superoxide anion improved survival with more severe sepsis and high-control mortality rates but was less effective or harmful with less severe sepsis. Extrapolated clinically, inhibition of superoxide anion may be most efficacious in septic patients with severe sepsis and a high risk of death.
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PMID:Severity of sepsis alters the effects of superoxide anion inhibition in a rat sepsis model. 1516 52

The aim of this study was to investigate effects of sesame oil on oxidative stress after the onset of sepsis in rats. Effects of sesame oil on lipid peroxidation, superoxide anion, superoxide dismutase, catalase, glutathione, and nitrite after the onset of endotoxin intoxication were determined. To further examine the protective effect of sesame oil on sepsis, a mortality study was also conduced in cecal ligation and puncture-induced sepsis in rats. Sesame oil was given orally 6 h after endotoxin administration and cecal ligation and puncture, and parameters were then measured in another 6 h. Data demonstrated that a single dose of sesame oil reduced lipid peroxidation 6 h after endotoxin intoxication. Superoxide anion counts were decreased, glutathione levels were increased, and activities of superoxide dismutase and catalase, as well as nitrite levels, were not altered in lipopolysaccharide plus sesame oil-treated groups compared with lipopolysaccharide-treated groups. Furthermore, sesame oil given 6 h after cecal ligation and puncture significantly increased survival rate. Thus, we suggested that sesame oil could be used as a potent antioxidant to reduce oxidative stress after the onset of sepsis in rats.
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PMID:Effects of sesame oil on oxidative stress after the onset of sepsis in rats. 1554 32

We studied the changes in superoxide dismutase activity in organs of Galleria mellonella larvae infected with two strains of Bacillus thuringiensis. A considerable increase in superoxide dismutase activity was observed at the initial stages of infection, later the enzyme activity decreased and this decrease was timed to cessation of feeding and development of sepsis in the infected larvae. Changes in the enzyme activity in the organs of larvae infected with a highly virulent strain of B. thuringiensis correlated with the stages of infection. Involvement of superoxide dismutase in prevention of oxidative stress in the infected larvae is discussed.
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PMID:[Changes in superoxide dismutase activity in various larval organs of greater wax moth (Galleria mellonella L., Lepidoptera: Pyralidae) induced by infection with Bacillus thuringiensis ssp. galleriae]. 1576 35

We investigated the role of oxidative stress in the pathogenesis of septic ileus. Sepsis was induced by intraperitoneal (i.p.) injection of lipopolysaccharides (LPS, 20 mg kg(-1)) in mice. The effect of two i.p. injections of superoxide dismutase [polyethylene glycol (PEG)-SOD, 4000 U kg(-1)] and catalase (PEG-CAT, 15,000 U kg(-1)) was investigated on gastric emptying, intestinal transit and total nitrite plasma concentrations. We also performed immunohistochemical experiments on gastric and ileal tissue. LPS significantly delayed gastric emptying and intestinal transit while plasma nitrite levels increased. Polyethylene glycol (PEG)-SOD reversed the endotoxin-induced delay in gastric emptying and improved the delay in intestinal transit without effect on plasma nitrite levels. PEG-CAT slightly improved the delay in gastric emptying without effect on intestinal transit. Immunohistochemistry showed the presence of nitrotyrosine (NT) and 4-hydroxy-2-nonenal (HNE) in the gastric and ileal mucosa of LPS-treated mice. Treatment with PEG-SOD or PEG-CAT of LPS mice diminished the presence of NT or HNE in both tissues. In addition, LPS induced a significant increase in inducible nitric oxide synthase (iNOS)-positive residential macrophages in the external musculature of stomach and ileum, which significantly decreased after PEG-SOD or PEG-CAT treatment. The present results support a role for oxidative and nitrosative stress in the pathogenesis of septic ileus in mice.
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PMID:Role of oxidative stress in the pathogenesis of septic ileus in mice. 1578 45


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