Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Severity of renal injury and recovery of function in acute renal failure (ARF) are strongly related not only to the magnitude and nature of ARF insult but also to numerous factors in the host which govern renal susceptibility to the insult and repair of renal lesion. Prior ARF affords resistance to a rechallenge with the same or different ARF insult. The mechanisms for this acquired resistance to ARF have not been well established, but suggested mechanisms include (a) increased resistance of regenerated tubular epithelial cells to a rechallenge, (b) glomerular refractoriness to vasoactive substances, (c) failure of damaged kidney to concentrate the toxic substance, (d) enhanced antioxidant enzyme activity in glomeruli, and (e) increased Na(+)-K(+)-ATPase activity in regenerated tubular epithelial cells. Controversy still exists regarding roles of these factors in the resistance to renal failure. Functional and morphologic recovery of postischemic kidney is enhanced by antecedent unilateral nephrectomy but delayed in the presence of the contralateral kidney. The mechanisms for the effect of uninephrectomy remain unsettled. Recent studies suggest contributions of changes in preglomerular vascular resistance; alterations in the environment which follow ischemia to all functioning excretory renal tissues; and altered production and release of vasoactive substances such as angiotensin, endothelin, thromboxane, and atrial natriuretic peptide.
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PMID:Factors affecting severity of renal injury and recovery of function in acute renal failure. 132 11

Injury to the gastrointestinal tract by oxygen dependent processes is important in ischemia, inflammatory bowel disease, and necrotizing enterocolitis. The Caco-2 cell line is an important tool in assessing various gastrointestinal functions and offers a unique opportunity to assess gastrointestinal oxidant metabolism on a cellular level. However, some Caco-2 cell functions change with time after confluence. To determine if antioxidant enzyme activity changes during differentiation, Caco-2 cells were grown to confluence, and superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase activities and specific mRNA content were quantitated. With time after confluence the enzymes demonstrated a small, but statistically significant increase in activity. Neither superoxide dismutase nor glutathione peroxidase mRNA levels correlated with enzyme activity changes. Catalase mRNA levels increased as catalase activity increased. Thus, differentiated Caco-2 cells express superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase activities and the superoxide dismutase, glutathione peroxidase, and catalase genes. Superoxide dismutase activity and glutathione peroxidase activity do not correlate with mRNA levels, and suggest that regulation may be at a level other than transcription. The correlation between catalase activity and catalase mRNA suggests differentiation may occur at transcription. If Caco-2 cells are used to elucidate oxidative metabolism, changes in activities of antioxidant enzymes as a function of cell differentiation should be considered.
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PMID:Antioxidant enzymes in the differentiated Caco-2 cell line. 142 66

We hypothesized that low-dose pretreatment of an intact animal with a nontoxic derivative of endotoxin, monophosphoryl lipid A (MPL), would induce protection against cardiac ischemia/reperfusion (I/R) injury. The purposes of this study were to investigate whether MPL pretreatment would induce functional protection against cardiac I/R injury, to delineate the temporal induction of protection, and to examine antioxidant enzyme induction as a mechanism of protection. Rats were administered a 5 mg/kg dose of MPL at 2 hours and 24 hours before a 25-minute, global, 37 degrees C ischemic insult followed by reperfusion (modified Langendorff). At 40 minutes of reperfusion, ventricular function was assessed (ventricular balloon; developed pressure, rate of contraction, rate of relaxation). Hearts from rats pretreated with MPL 24 hours before isolation exhibited preservation of ventricular function (p less than 0.05). After I/R, hearts from rats pretreated with MPL 24 hours before isolation had increased (p less than 0.05) catalase activity compared to saline pretreated controls and rats pretreated with MPL 2 hours before isolation. We conclude that (1) pretreatment with MPL induces functional protection against cardiac I/R injury, (2) protection (not evident at 2 hours) is maximal at 24 hours, suggesting enzyme induction, and (3) increased catalase activity correlates with the functional protection.
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PMID:Pretreatment with a nontoxic derivative of endotoxin induces functional protection against cardiac ischemia/reperfusion injury. 185 44

Efforts to reduce reperfusion injury have focused on exogenous therapies; however, endogenous attenuation of reperfusion injury can be induced by a single sublethal dose of endotoxin (ETX) prior to ischemia. The purposes of this study were to investigate (i) the early neutrophil-endothelial (PMN-EC) adherence, (ii) the associated myocardial oxidant stress, (iii) the relationship of oxidant stress to antioxidant enzyme activity, and (iv) the correlation of increased antioxidant enzyme activity to myocardial recovery following ischemia/reperfusion (I-R) injury at 36 hr. Rats were administered a sublethal dose (2% of LD50) of endotoxin (500 micrograms/kg, ip, Salmonella typhimurium). At 6 hr, myocardial neutrophil accumulation (histology), hydrogen peroxide (H2O2) levels, and myocardial tissue glutathione (glutathione and oxidized glutathione) levels were determined. At 24 hr myocardial tissue glutathione levels and catalase (CAT) activity were assayed. At 36 hr, myocardial tissue superoxide dismutase, glutathione peroxidase, glutathione reductase, catalase, and glucose-6-phosphate dehydrogenase (G-6-PD) were assayed. At 36 hr, hearts were subjected to a standard (20 min, global, 37 degrees C) ischemic insult followed by reperfusion. At 40 min of reperfusion, ventricular function was assessed (ventricular balloon; ventricular developed pressure +dP/dt, and -dP/dt).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Induction of endogenous tissue antioxidant enzyme activity attenuates myocardial reperfusion injury. 219 33

We have previously demonstrated that induction of the heat-shock response in rats results in improved recovery of isolated Langendorff-perfused rat hearts subjected to low-flow ischemia followed by reperfusion (Currie et al., 1988). The mechanisms underlying this protective effect of heat-shock are uncertain although the protection was associated with enhanced content of the antioxidant enzyme catalase but not superoxide dismutase or glutathione peroxidase (Currie et al., 1988). Various investigators have suggested the importance of improved energy metabolism in determining recovery following ischemia (Pasque and Wechsler, 1984; Haas et al., 1984; Devous and Lewandowski, 1987). We therefore examined, using a working rat heart model subjected to 10 or 15 min zero flow ischemia whether changes in energy metabolites could account for the protective effect of the heat-shock response. Hearts perfused 24 h after induction of heat-shock failed to demonstrate significant improvement of recovery following 10 min ischemia, however recovery was significantly enhanced in hearts reperfused after 15 min ischemia. Ischemia produced a depression in both ATP and creatine phosphate (CP) content whereas a moderate elevation in ADP and AMP and a marked increase in tissue lactate were evident. These changes were unaffected by prior heat-shock treatment. For both durations of ischemia tissue metabolites were determined during early (5 min) and late (30 min) reperfusion. Although partial recovery in high energy phosphates and a return of ADP, AMP and lactate to near-normal levels were evident, no differences in energy products were observed between hearts from normal or heat-shocked animals, in spite of significantly enhanced recovery.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Improved post-ischemic ventricular recovery in the absence of changes in energy metabolism in working rat hearts following heat-shock. 223 33

The purposes of this study were to determine whether exercise training induces increases in skeletal muscle antioxidant enzymes and to further characterize the relationship between oxidative capacity and antioxidant enzyme levels in skeletal muscle. Male Sprague-Dawley rats were exercise trained (ET) on a treadmill 2 h/day at 32 m/min (8% incline) 5 days/wk or were cage confined (sedentary control, S) for 12 wk. In both S and ET rats, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) activities were directly correlated with the percentages of oxidative fibers in the six skeletal muscle samples studied. Muscles of ET rats had increased oxidative capacity and increased GPX activity compared with the same muscles of S rats. However, SOD activities were not different between ET and S rats, but CAT activities were lower in skeletal muscles of ET rats than in S rats. Exposure to 60 min of ischemia and 60 min of reperfusion (I/R) resulted in decreased GPX and increased CAT activities but had little or no effect on SOD activities in muscles from both S and ET rats. The I/R-induced increase in CAT activity was greater in muscles of ET than in muscles of S rats. Xanthine oxidase (XO), xanthine dehydrogenase (XD), and XO + XD activities after I/R were not related to muscle oxidative capacity and were similar in muscles of ET and S rats. It is concluded that although antioxidant enzyme activities are related to skeletal muscle oxidative capacity, the effects of exercise training on antioxidant enzymes in skeletal muscle cannot be predicted by measured changes in oxidative capacity.
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PMID:Skeletal muscle oxidative capacity, antioxidant enzymes, and exercise training. 238 14

In this study, we examined the effects of oxidative stress adaptation on myocardial ischemic reperfusion injury. Oxidative stress was induced by injecting endotoxin (0.5 mg/kg) into the rat. After 24 h, rats were killed, hearts were isolated, and the effects of ischemia-reperfusion were studied using an isolated working heart preparation. The development of oxidative stress was examined by assessing malonaldehyde production in the heart. The antioxidant defense system was studied by estimating antioxidant enzyme activities and ascorbate- as well as thiol-dependent antioxidant reserve. The results of our study indicated that endotoxin induced oxidative stress within 1 h of treatment; the stress was reduced progressively and steadily up to 24 h. The antioxidant enzymes superoxide dismutase, catalase, glutathione (GSH) peroxidase, and GSH reductase were lowered up to 2 h and then increased. Both thiol- and ascorbate-dependent antioxidant reserve were enhanced, but the enhancement of the former was only transitory. After 24 h, endotoxin provided adequate protection to the heart from the ischemic-reperfusion injury, as evidenced by improved left ventricular function and aortic flow. Our results suggest that the induction of oxidative stress by endotoxin-induced adaptive modification of the antioxidant defense in the heart, thereby reducing ischemic-reperfusion injury.
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PMID:Myocardial adaptation to ischemia by oxidative stress induced by endotoxin. 748 60

Upon exposure to a transient ischemia, the distal tubule of the kidney often escapes the severe damage which afflicts the proximal tubule. To ascertain whether this feature of the distal tubule is attributable to its intrinsic cellular properties, we focused on two pairs of unique tubule segments; distal versus proximal convoluted tubules in the superficial cortex and distal versus proximal straight tubules in the outer stripe of the outer medulla. These tubules were chosen because, firstly, they can be identified by morphology and immunostaining, and secondly, each pair has the same anatomical relationship to the circulation. Detailed morphometric analyses were performed six hours following unilateral transient ischemia in adult rats to semiquantitate the local tissue damage in these specific nephron segments. The architecture of the distal convoluted and straight tubules was remarkably well preserved, contrasting to the moderate to extensive necrotic changes seen in the proximal tubules. In search of the potential intrinsic cellular mechanism that underlies the observed difference, we examined the segmental distribution along the nephron of manganese superoxide dismutase gene transcripts by in situ hybridization. This antioxidant enzyme gene was expressed primarily in the distal tubules with contrastingly low levels of expression in the proximal tubules. Moreover, following ischemia-reperfusion, this distal tubule-dominant pattern was further accentuated immediately following reperfusion. The study indicates that the marked difference between the proximal and distal tubules in their susceptibility to injury in vivo is attributable to their intrinsic cellular properties, which include the local level of antioxidants.
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PMID:Strategic locus for the activation of the superoxide dismutase gene in the nephron. 753 59

Adaptation to various forms of stress has been found to be associated with increased cellular tolerance to myocardial ischemia. In this study, the effects of myocardial adaptation to oxidative stress was examined by injecting rats with endotoxin (0.5 mg/kg) and its non-toxic derivative, lipid A (0.5 mg/kg). Both compounds exerted oxidative stress within 1 h of treatment as evidenced by enhanced malonaldehyde formation. The oxidative stress disappeared steadily and progressively with time in concert with the appearance of the induction of glutathione and antioxidative enzymes that included superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. After 24 h of endotoxin or lipid A treatment, the amount of oxidative stress and antioxidant enzyme levels were significantly lower and higher, respectively, compared to those at the baseline levels. Corroborating these results, both endotoxin and lipid A provided protection against myocardial ischemia and reperfusion injury as evidenced by a significantly improved postischemic recovery of left ventricular functions. The data presented here demonstrates that a controlled amount of oxidative stress induces the expression of intracellular antioxidants that can result in enhanced myocardial tolerance to ischemia. This suggests that myocardial adaptation to oxidative stress may be a potential tool for reduction of ischemic/reperfusion injury.
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PMID:Oxidative stress adaptation improves postischemic ventricular recovery. 779 47

Hearts from rats treated with interleukin-1 (IL-1) intraperitoneally developed a rapid (6 h after IL-1), transient increase in neutrophils, tissue hydrogen peroxide (H2O2), and oxidized glutathione (GSSG) levels, and a subsequent (36 h after IL-1) increase in myocardial glucose-6-phosphate dehydrogenase (G6PD) activity and tolerance to ischemia-reperfusion. In the present investigation, we found that rats treated similarly with IL-1 had increased numbers of neutrophils in their kidneys, which were comparable to myocardial neutrophil increases, but did not develop increased renal tissue H2O2 or GSSG levels acutely (6 h after IL-1) or increased G6PD activity or resistance to ischemia-reperfusion injury later (36 h after IL-1). Our findings indicate that IL-1 treatment increased neutrophil accumulation in rat kidneys but did not increase oxidative stress, antioxidant enzyme activity, or resistance to ischemia-reperfusion injury. We conclude that organ-to-organ differences exist with respect to IL-1-induced tolerance.
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PMID:Interleukin-1 treatment increases neutrophils but not antioxidant enzyme activity or resistance to ischemia-reperfusion injury in rat kidneys. 784 98


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