ISSN:1071-5762    

DOI:10.3109/10715769509150323

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

A superoxide dismutase (SOD) has been purified to homogeneity from the fungal pathogenAspergillus fumigatususing a combination of cell homogenization, isoelectric focusing and gel filtration FPLC. The N-terminal amino acid sequence of the purified enzyme demonstrated substantial homology to known Cu, Zn superoxide dismutases for a range of organisms, includingNeurospora crassaandSaccharomyces cerevisiae. The enzyme subunit has a pl of 5.9, a relative molecular mass of 19 kDa and a spectral absorbance maximum of 550nm. The non reduced enzyme has a relative molecular mass of 95 kDa. The enzyme remained active after prolonged incubation at 70°C and was pH insensitive in the range 7-11. Potassium cyanide and diethyldithiocarbamate, known Cu, Zn SOD inhibitors, caused inhibition of the purified enzyme at working concentrations of 0.25 mM, whilst sodium azide and o-phenanthroline demonstrated inhibition at higher concentrations (10-30 mM). SOD activity was also detectable in culture filtrate ofA. fumigatus. This enzyme may have a potential role as a virulence factor in the avoidance of neutrophil and phagocyte oxidative burst killing mechanisms.

ISSN:1071-5762    

DOI:10.3109/10715769509150324

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

The influence of peplomycin (PLM) on the respiratory burst of peripheral blood polymorphonuclear leukocytes (PMN) was investigated. Short-term (5 min) treatment of human PMN with 0.1μg/ml to 100μg/ml of PLM increased phorbol myristate acetate (PMA)-and formyl-methionyl-leucyl-phenylalanine (FMLP)-induced luminol-dependent chemiluminescence. PMN, as well as alveolar macrophages from rabbits treated with 0.5 to 1.0 mg/kg of peplomycin per day for 5 days, generated more superoxide (O2−) than the cells from untreated rabbits. In both PLM-treated and untreated PMN, chemiluminescence induced by FMLP and PMA was decreased to less than 50% of the control by staurosporine, superoxide dismutase (SOD) and catalase. However, the peak intensity in PLM-untrcated PMN was decreased to about 30% of the control by genislein, while this agent induced a slight decrease in peak intensity in the PLM-treated PMN. Inositol triphosphate and diacyl glycerol levels were not clearly increased by PLM, but an increase of intracellular Ca and a shift of protein kinase C (PKC) to the membrane occurred in PMN within 1 min after PLM treatment. Western blotting revealed that the tyrosine phosphorylation of a 115 kDa protein was upregulated by 5 to 50μg/ml of PLM. While, PLM suppressed SOD activity in alveolar macrophages and PMN. These results seem to indicate that PLM increases the respiratory burst of PMN and macrophages both by way of direct PKC activation and by the upregulation of protein tyrosine phosphorylation. This increased reactive oxygen generation, together with the suppression of SOD activity seems to be tissue-impairing.

ISSN:1071-5762    

DOI:10.3109/10715769509150325

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Infestation of sheep byL. cuprinalarvae produces extensive skin wounds, severe dermatitis, hyperammonaemia and stress with adrenal necrosis and haemmorhage. In infested sheep, intramuscular (im) injections of Dl-Alpha tocopherol induced wool shedding and Desferrioxamine im prevented declines in white blood cells (WBC). In further trials, daily im injections of sodium ascorbate with Dl-alpha tocopherol, desferrioxamine and oral butylated-hydroxyanisole prevented adrenal damage and induced adrenocortical hypertrophy of the zona fasciculata. The treatment boosted the levels of mature and juvenile neutrophils, and blood glucose. Increases in toxic ammonia levels were correlated with increased toxic and band neutrophils, and globulin levels in treated sheep and toxic neutrophils in non-treated sheep. Decreases in serum zinc were correlated with declining lymphocytes and globulin levels. The results suggested that antioxidants protect and enhance adrenal activation in hyperammonaemic toxaemia. The changes in WBC, globulins and glucose were consistent with protected adrenocortical activation.

ISSN:1071-5762    

DOI:10.3109/10715769509150326

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Redox active iron chelatable to bleomycin is often present in the plasma of cord blood samples taken from preterm and term babies. The low caeruloplasmin and high ascorbate levels in plasma at birth may allow this iron to exist in the reduced ferrous state. In support of this postulate thirteen cord blood samples showing the presence of low molecular mass iron were able to degrade DNA in the presence of bleomycin and plasma.

ISSN:1071-5762    

DOI:10.3109/10715769509150327

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Rats subjected to tourniquet shock suffer a severe form of circulatory shock, tissue and organ oxidative stress, and final multiple system organ failure (MSOF) and death of the animals within 24 h of tourniquet release. The oxidative damage observed in hind-limb muscle tissue after reperfusion does not by itself account for the final systemic and lethal MSOF. We have postulated that organ failure has its genesis in a primary perfusion abnormality, e.g. the hind limbs, which is followed by secondary hypoperfusion of other organs, such as the liver, as has been shown to be the case in several septic shock models. It has also been shown that injured or necrotic tissue can activate neutrophils, Küpffer cells, platelets, and both the complement and coagulation cascades. In turn, complement activation also leads to neutrophil and Küpffer cell activation as assessed by their capacity to generate oxyradicals. Herein we have evaluated the potential protective effect of ibuprofen on hepatic oxygen-derived free radical production, as well as its effects on both polymorphonuclear leucocyte (PMN) activation and liver infiltration. The protective effect of ibuprofen on hepatic oxidative injury was assessed by determining total thiol groups (SH), thiobarbituric acid-reactive substances (TBARS), and by the release of aspartic acid (AsT) and alanine (AIT) aminotransferases in control animals, in animals subjected to 5 h of tourniquets, and in animals after 2 h of hind-limb reperfusion. Liver infiltration by PMNs was determined by histology after staining with cosin-hematoxylin, and PMN activation by their capacity to reduce nitro blue tetrazolium (NBT). Our results show that total hepatic thiol content decreased significantly, over and above the the normal circadian decrease in liver glutathione, after the 5 h tourniquet period (from 6.16±0.97 to 4.07±0.21μmoles/g w.w). The decrease in liver thiols in animals pretreated with ibuprofen was not significantly different from that in control animals (from 5.76±0.21 to 4.69±0.19,μmoles/g w.w), and could be accounted for by the circadian effect. A further significant decrease was observed in the control (3.01±0.12μmoles/g w.w), but not in the ibuprofen pretreated rats (4.65±0.16μmoles/g w.w), after the 2 h reperfusion period. TBARS production remained essentially unchanged during the tourniquet period in both the control and ibuprofen pretreated animals (average 260 nmoles/g w.w), but increased significantly after hind-limb reperfusion in the control animals (386.9±18.5 nmoles/g w.w), but not in the ibuprofen treated rats (267.2±7.4 nmoles/g we.w). The protective effect of ibuprofen was also evident in plasma aminotransferase levels (AsT and AIT) which increased 14 and 6-fold, respectively, during the experimental period in the untreated rats, and only 6 and 3-fold in the animals pre-treated with the drug. No significant differences were observed in PMN liver infiltration in any of the animals, nor at any of the different time periods under study. Nevertheless, our results indicate that there is a 3-fold increase (over control values) in the number of circulating activated PMNs after hind-limb reperfusion in the non-protected control rats, and only a 2-fold increase in those protected by ibuprofen. It is concluded that ibuprofen: a) protects rat livers from the oxidative stress which results after 2 h of reperfusion of rat hind limbs subjected to 5 h of ischemia by means of tourniquets, and b) significantly decreases the number of NBT-positive PMNs in the systemic circulation after hind-limb reperfusion.

ISSN:1071-5762    

DOI:10.3109/10715769509150328

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

The forms of ferrate (V) which are derived from the one-electron reduction of potassium ferrate (K2FeO4) by ethanol radicals react with representative amino acids (glycine, methionine, phenylalanine and serine) at rates that are greater than 105M near pH 10. The predominant interaction in the alkaline pH range is between the protonated ferrate (V) species. HFeO42, and the amino acid anion. Fe(V) + amino acid Fe(III) + NH3+α-keto acidThe rate-determining process is the two electron reduction of ferrate(V) to iron(III) with oxidation and subsequent deamination of the amino acid. The reaction appears to involve an entry of the amino acid into the inner coordination sphere of ferrate (V). In all cases, ferrate(V) exhibits preferred attack on the amino group in contrast to the OH radical which attacks the thioether site of methionine and the phenyl ring of phenylalanine.

ISSN:1071-5762    

DOI:10.3109/10715769509150329

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor