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

Free radicals generated during purine catabolism or by activated granulocytes cause tissue injury by peroxidation of lipid membranes. In a canine model of sepsis initiated by intravenous live Escherichia coli, fluorescent products of lipid peroxidation (FP) were measured in serum. Four groups of five dogs infused with 10(9)E. coli/kg were analyzed--I: no further treatment; II: prior depletion of granulocytes with a cytotoxic antibody; III: pre-treatment with superoxide dismutase and catalase; and IV: resuscitation after bacterial infusion to maintain cardiac output greater than 80% of pre-bacteremic levels. In Groups I, II, and III, cardiac output fell to less than 50% of baseline within 1 hr and remained there throughout the study. FP in Groups I and II rose to greater than 200% of baseline (P less than .02 and less than .03). In Groups III and IV, FP did not rise significantly from baseline. The rise in serum FP and the prevention of this rise by-treatment with antioxidants indicate generation of oxygen radicals. Their presence had no effect on hemodynamic parameters. Granulocyte depletion did not alter appearance of FP; however, prevention of low cardiac output blocked FP formation. These data suggest that oxygen free radicals were generated by tissue ischemia, rather than by granulocytes, in this model of septic shock.
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PMID:Oxygen free radical activity during live E. coli septic shock in the dog. 304 73

Neutrophils have been implicated in the pathogenesis of acute lung injury associated with clinical and experimental sepsis. Data from in vitro systems and experimental animals have suggested that neutrophil-derived oxidants, particularly H2O2, may be primarily responsible for endothelial damage, vasoconstriction, and lung edema. With the use of endotoxin infusion as an in vivo model of sepsis we tested the hypothesis that pretreatment with catalase, a peroxide scavenger, would ameliorate the resultant changes in pulmonary vasoconstriction and lung fluid balance. Paired experiments were performed in 16 goats with chronic lung lymph fistulas. One group of animals (n = 7) received endotoxin first alone and then again, several days later, after pretreatment with Ficoll-linked catalase. As a control, identical experiments were performed in a separate group (n = 6) with Ficoll-linked albumin substituted for Ficoll-catalase. A third group (n = 3) was given endotoxin alone and then again during a continuous infusion of catalase. Plasma and lymph levels of catalase were comparable to or exceeded those previously shown to be completely protective in isolated perfused lung preparations and in vitro systems. Endotoxin caused neutropenia, pulmonary arterial hypertension, decreased cardiac output, and increases in lymph flow to approximately three times base line, with a return of all variables toward control values by 6 h. Catalase pretreatment produced no significant differences in any of these variables. These experiments do not support a role for H2O2 as a mediator of acute lung injury due to endotoxemia.
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PMID:Effect of intravenous catalase on the pulmonary vascular response to endotoxemia in goats. 328 99

Live Escherichia coli were infused into anesthetized cats given 0.6 ml bile/kg and 80 mM HCl into the stomach. Systemic and pulmonary arterial blood pressures, cardiac output, and gastric blood flow were monitored. Gastrointestinal total wall and mucosal blood flow were measured by microspheres. The microscopic mucosal damage was graded 0-4 (stomach) or 0-5 (intestine). One group of cats (N = 8) received 5 mg yeast CuZn superoxide dismutase (SOD) as a bolus before bacteria followed by infusion 50 mg/3 hr. Four of these cats were also given catalase in the same dose. Controls (N = 8) had no treatment. After 3 hr gastric ulceration (grades 2-4) was found in controls but only in 50% of treated cats (P less than 0.1). About 50% and 25% of the cats in both groups developed significant small intestinal and colonic mucosal damage, respectively. SOD or SOD/catalase had no effect on late systemic hypotension, decrease in cardiac output, or transient increase in pulmonary pressure. Total gastric blood flow did not change, while at late sepsis gastric mucosal flow was decreased in the treated group. Small intestinal mucosal flow decreased in both series. It is concluded that free oxygen radicals may be of partial importance in the development of sepsis-induced gastric, but not intestinal, mucosal damage.
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PMID:Role of free oxygen radicals in the development of gastrointestinal mucosal damage in Escherichia coli sepsis. 391 36

A 52 yr old Caucasian female (F. E.) had hemolytic anemia, a leukemoid reaction, and fatal sepsis due to Escherichia coli. Her leukocytes ingested bacteria normally but did not kill catalase positive Staphylococcus aureus, Escherichia coli, and Serratia marcescens. An H(2)O(2)-producing bacterium, Streptococcus faecalis, was killed normally. Granule myeloperoxidase, acid and alkaline phosphatase, and beta glucuronidase activities were normal, and these enzymes shifted normally to the phagocyte vacuole (light and electron microscopy). Intravacuolar reduction of nitroblue tetrazolium did not occur. Moreover, only minimal quantities of H(2)O(2) were generated, and the hexose monophosphate shunt (HMPS) was not stimulated during phagocytosis. These observations suggested the diagnosis of chronic granulomatous disease. However, in contrast to control and chronic granulomatous disease leukocytes, glucose-6-phosphate dehydrogenase activity was completely absent in F. E. leukocytes whereas NADH oxidase and NADPH oxidase activities were both normal. Unlike chronic granulomatous disease, methylene blue did not stimulate the hexose monophosphate shunt in F. E. cells. Thus, F. E. and chronic granulomatous disease leukocytes appear to share certain metabolic and bactericidal defects, but the metabolic basis of the abnormality differs. Chronic granulomatous disease cells lack oxidase activity which produces H(2)O(2); F. E. cells had normal levels of oxidase activity but failed to produce NADPH due to complete glucose-6-phosphate dehydrogenase deficiency. These data indicate that a complete absence of leukocyte glucose-6-phosphate dehydrogenase with defective hexose monophosphate shunt activity is associated with low H(2)O(2) production and inadequate bactericidal activity, and further suggest an important role for NADPH in the production of H(2)O(2) in human granulocytes.
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PMID:Complete deficiency of leukocyte glucose-6-phosphate dehydrogenase with defective bactericidal activity. 440 Dec 71

Reactive oxygen metabolites are believed to be important mediators of sepsis- or lipopolysaccharide (LPS)-induced adult respiratory distress syndrome. EUK-8 is a novel, synthetic, low-molecular-weight salen-manganese complex that exhibits both superoxide dismutase and catalase activities in vitro. We hypothesized that treatment with EUK-8 would ameliorate pulmonary dysfunction in a porcine model of LPS-induced adult respiratory distress syndrome. At T = -18 h, pigs received an intravenous priming dose of LPS (20 micrograms/kg). Anesthetized ventilated swine were randomized to receive 1) no further treatment (n = 5); 2) LPS (250 micrograms/kg from T = 0 to 60 min, n = 6); 3) LPS and a low dose of EUK-8 (10-mg/kg bolus at T = -15 min and 1 mg/kg.h from T = 0 to 240 min, n = 6) or 4) LPS and a higher dose of EUK-8 (10-mg/kg bolus and 3 mg/kg.h, n = 6). Treatment with EUK-8, particularly at the higher dose, significantly attenuated many of the features of LPS-induced acute lung injury, including arterial hypoxemia, pulmonary hypertension, decreased dynamic pulmonary compliance and pulmonary edema. LPS caused an increase in lung tissue malondialdehyde content that was abrogated in both EUK-8-treated groups. EUK-8 treatment had no effect on circulating plasma levels of tumor necrosis factor-alpha, thromboxane B2 or 6-keto-prostaglandin F1 alpha. We conclude that EUK-8 prevents many of the manifestations of LPS-induced adult respiratory distress syndrome in pigs by detoxifying reactive oxygen metabolites without affecting the release of other important proinflammatory mediators.
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PMID:EUK-8, a synthetic superoxide dismutase and catalase mimetic, ameliorates acute lung injury in endotoxemic swine. 747 69

The prognostic potential of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) was evaluated in sepsis. Enzyme concentrations were determined in samples obtained from septic patients at time of diagnosis. Statistically significant increases in activities of total plasma SOD (P < 0.003, n = 32), erythrocyte (RBC) SOD (P < 0.007, n = 16), plasma CAT (P < 0.0001, n = 32), and RBC CAT (P < 0.005, n = 16) were found in septic patients when compared with healthy adult controls (n = 7). Further, within the group of septic patients, statistically significant differences were found for total plasma SOD (P < 0.05) and plasma CAT (P < 0.009) (but not for RBC determinations) when survivors (n = 15) were compared with nonsurvivors (n = 17). No significant differences were found for either plasma or RBC enzyme concentrations when patients who developed adult respiratory distress syndrome were compared with those who did not. The most striking finding was that plasma total SOD values of > 10 kU/L were found in 7 of 21 (30%) patients who did not survive their sepsis and that these values did not overlap with any surviving patients or controls. However, while high total plasma SOD activity appears to have some potential as a prognostic indicator, lower values (0.0-8.8 kU/L) do not. For plasma CAT, despite finding statistically significant differences between survivors and nonsurvivors, the substantial overlap in the values obtained for the two groups limits the practical prognostic potential of this enzyme.
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PMID:Prognostic role of antioxidant enzymes in sepsis: preliminary assessment. 776 6

Due to the chemical nature of oxygen, its tendency to accept a single electron to create the superoxide radical, and the fact that every aerobic cell must deal with this difficult situation, the production of oxygen-derived free radicals is an almost universal accompaniment to cellular pathology. In sepsis or immunologic disease, the activated phagocyte becomes a major producer of active oxygen species, contributing to oxidative injury to host tissues. The resulting oxidative stress is seriously exacerbated by the availability of iron, liberated from the body's store of ferritin. The antioxidant vitamins and the body's antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) can help to restore and maintain proper oxidant/antioxidant balance.
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PMID:Oxygen-derived free radicals. 792 95

In addition to detoxifying peroxides generated by aerobic metabolism, the catalases of pathogenic bacteria have also been hypothesized to serve as virulence factors by enabling microorganisms to resist the oxidative bursts of host inflammatory cells. Using transposon mutagenesis of the hktE gene, encoding the Haemophilus influenzae structural gene for catalase, we constructed defined catalase mutants of H. influenzae strains Rd- and Eagan b+. These mutants show no detectable catalase production during exponential or stationary phases or following induction with hydrogen peroxide or ascorbic acid, indicating that hktE is the only functional hydroperoxidase gene present in these two strains of H. influenzae. Exponential-phase cultures of hktE mutants are 8- to 25-fold more sensitive to hydrogen peroxide than the wild type. Using the infant rat model, hktE mutants of strain Eagan b+ were 2.3-fold less virulent than the wild type following intraperitoneal inoculation (P = 0.07). When administered intranasally, the Eagan b+ hktE mutant produced wild-type levels of bacteremia and nasal colonization. The results of this study show that while the H. influenzae hktE gene is important for survival in the presence of peroxides, deletion of the gene produces only a modest reduction in ability to cause lethal sepsis following parenteral challenge and no change in ability to colonize following intranasal inoculation in the infant rat model of infection.
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PMID:Characterization and virulence analysis of catalase mutants of Haemophilus influenzae. 792 66

Sepsis, as infection associated to systemic manifestations, was produced in rats by cecal ligation and double perforation. Sham-operated rats were used as controls. The spontaneous chemiluminescence of rat adductor muscle and liver were measured at 6, 12, 24, and 30 h after the surgical procedure. Muscle chemiluminescence showed a maximal increase of about twofold (control emission 10 +/- 1 cps/cm2) after 6-12 h of sepsis, while liver chemiluminescence increased by about 80% (control emission: 11 +/- 1 cps/cm2) after 24 h of sepsis. The activities of muscle antioxidant enzymes were found maximally diminished after 12 h of sepsis: 46% decrease for Mn-superoxide dismutase, 83% decrease for catalase, and 55% decrease for glutathione peroxidase. In liver, only catalase activity showed a 52% decrease after 24 h of sepsis. State 3 oxygen uptake of muscle mitochondria with either malate-glutamate or succinate as substrates was 40% decreased after 12 h of sepsis in both cases. State 4 oxygen uptake of muscle mitochondria was not affected. The rate of H2O2 production of muscle mitochondria after 12 h of sepsis with either malate-glutamate or succinate as substrates was increased about 2.5 times but was not affected when assayed in the presence of as rotenone and antimycin. The oxygen uptake of liver mitochondria isolated from septic rats did not show differences as compared with those of control rats after 6 to 24 h of sepsis. Oxidative stress appears to occur in skeletal muscle early at the onset of the septic syndrome, with inhibition of active mitochondrial respiration and inactivation of antioxidant enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oxidative stress in muscle and liver of rats with septic syndrome. 800 29

Liver specimens obtained immediately after death from eight severely malnourished children were examined by electron microscopy, and compared with seven liver biopsy specimens from children who had recovered from malnutrition. The liver cells from the fatal cases showed mitochondrial swelling, with coarse densities in the matrix, cholestasis, depletion of the endoplasmic reticulum and Golgi apparatus, diminished glycogen stores, prominent lipid deposits and focal cytoplasmic degradation. The nucleoli were enlarged. There was marked reduction in peroxisomes. In contrast, the biopsies from recovering children showed good cellular organisation, and a normal frequency of peroxisomes. Multiple factors, including sepsis, may lead to depletion of peroxisomes. Loss of peroxisomes may interrupt beta-oxidation of long-chain fatty acids and accentuate the accumulation of lipid. Moreover, a reduction in the concentration of catalase may remove one avenue for the detoxification of free radicals. As the concentration of other anti-oxidants, notably glutathione, is also reduced, free radical damage may occur, leading to lipid peroxidation of membranes, mitochondrial damage, pump failure and influx of water and electrolytes into the cell.
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PMID:Peroxisomes and the hepatic pathology of childhood malnutrition. 803 10


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