UMLS:C0432222 - FACTA Search

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47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Production of oxygen-free radicals has been proposed as one pathophysiologic mechanism for postburn cardiac contractile dysfunction in adults. To examine this hypothesis in young subjects, we studied the cardiac effects of polyethylene glycol-superoxide dismutase (PEG-SOD) and PEG-catalase (PEG-CAT), each given as 20 U/g of body weight with fluid resuscitation (Parkland formula), after a third-degree burn constituting 33% of the total body surface area in young (6- to 7-day old) guinea pigs (group 3, n = 12). Fluid-treated burns without scavenger therapy (group 2, n = 15) and sham burn controls (group 1, n = 15) were included. Animals were killed 24 hours postburn, and hearts were studied in vitro (Langendorff). Compared with sham burn controls, fluid-treated burns (group 2) had significant cardiac dysfunction as indicated by a lower peak systolic left ventricular (LV) pressure (LVP: 67 +/- 2 vs. 57 +/- 4 mm Hg, p = 0.01, mean +/- SEM), maximal rate of LV pressure development (+dP/dt max: 1169 +/- 45 vs. 988 +/- 45 mm Hg/second, p = 0.01), and fall (-dP/dt max: 1109 +/- 45 vs. 919 +/- 49 mm Hg/second, p = 0.01). In addition, LV function curves calculated for group 2 were shifted downward and to the right of those calculated for sham burn controls in the direction of contractile depression, p = 0.01. PEG-SOD/PEG-CAT treatment in burns did not significantly improve LVP (60 +/- 5 mm Hg), but scavenger therapy improved +/-dP/dt max values (1112 +/- 74 and 988 +/- 98 mm Hg/second, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The role of toxic oxygen metabolites in a young model of thermal injury. 747 25

Interaction between activated human polymorphonuclear leukocytes (PMNL) and endothelial regulation of isolated pig coronary artery tone was examined. PMNL were isolated from venous blood of healthy human volunteers. Pig coronary artery rings were incubated in an organ chamber, and isometric tension changes induced by opsonized zymosan (1 mg/ml)-activated PMNL were examined. Activated PMNL elicited dose-dependent contraction (maximum value 45.9 +/- 4.1% of precontraction, mean +/- SEM] in prostaglandin F2 alpha (PGF2 alpha)-precontracted rings. The contraction was markedly attenuated by superoxide dismutase (SOD 100 U/ml) to 9.9 +/- 2.4% (p < 0.001), but not by catalase (1,000 U/ml). After inhibition of basal production of endothelium-derived relaxing factor (EDRF) (nitric oxide, NO) by endothelial removal or by treatment of an inhibitor of NO synthase, NG-monomethyl-L-arginine (L-NMMA), PMNL also failed to induce the contraction. A 5-lipoxygenase inhibitor (AA-861) and a cyclooxygenase inhibitor (indomethacin) did not alter the contraction to activated PMNL significantly. Time course of oxygen free radical release from PMNL measured by luminol-dependent chemiluminescence was closely synchronized with that of the endothelium-dependent contraction elicited by PMNL. In each preparation of PMNL, the maximum luminescence count and the maximum contraction induced by activated PMNL showed significant positive correlation quantitatively (r = 0.958, p < 0.001). Activated human PMNL elicited endothelium-dependent contraction in isolated pig coronary arteries. The contraction may be mediated through inactivation of basal production of EDRF (NO) by superoxide anions released from PMNL.
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PMID:Activated human polymorphonuclear leukocytes elicit endothelium-dependent contraction in isolated pig coronary arteries. 768 46

We previously showed that oxygen radicals can induce airway hyperresponsiveness (AHR) in allergic sheep. The purpose of this study was to determine whether antigen challenge results in the generation of free oxygen radicals and if these radicals contribute to antigen-induced AHR. We first determined baseline airway responsiveness in seven Ascaris suum-sensitive sheep by calculating the cumulative provocative concentration of carbachol in breath units (BU; one BU defined as one breath of a 1% wt/vol carbachol solution) that increased specific lung resistance (SRL) 400% over baseline (PC400). On a different day, the sheep underwent inhalation challenge with A. suum antigen, SRL was measured before and immediately after challenge and then hourly for 2 h, at which time SRL had returned to baseline. The postchallenge PC400 was then measured. This procedure was repeated on separate occasions, each at least 14 days apart, except that the sheep were treated with an aerosol of catalase (CAT; 38 mg in 3 ml deionized water), the enzyme that catalyzes the decomposition of hydrogen peroxide (H2O2), at three different times: Trial 1, before antigen and then every 30 min after antigen challenge for 2 h; Trial II, 1 and 2 h after antigen challenge; and Trial III, only at 2 h after antigen challenge. In the control trial, antigen challenge caused a transient (mean +/- SEM) 303 +/- 48% increase in SRL over baseline (p < 0.05), and 2 h later, PC400 was reduced to 11.0 +/- 1.7 BU from a prechallenge value of 24.8 +/- 1.9 BU (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oxygen radicals contribute to antigen-induced airway hyperresponsiveness in conscious sheep. 843 Sep 55

This investigation was effected to determine the levels of the two antioxidant enzymes, superoxide dismutase (SOD) (EC 1.15.1.1) and catalase (CAT) (EC 1.11.1.6) in lung cancerous tissues and to compare with normal lung tissue in order to evaluate the antioxidant status in lung cancer. Fifteen lung carcinoma tissue samples and the normal counterparts from the same cases were homogenized and the cytosols obtained by ultracentrifugation (100,000 x g). SOD was assayed using a modification of the indirect nitroblue tetrazolium assay method, while CAT was measured by a spectrophotometric method. The data obtained are as follows: 1.42 +/- 0.24 U/mg protein (means +/- SEM) of SOD in lung cancer and 3.13 +/- 0.51 U/mg protein in normal lung tissue and 33.53 +/- 6.09 U/mg protein of CAT in lung cancer and 71.33 +/- 14.38 in normal lung tissue. The differences were found to be significant at the level of P < 0.01 for both enzymes. These low levels of the antioxidant enzymes in lung cancerous tissues can lead to elevated levels of reactive oxygen metabolites, resulting in damage to the key subcellular structures such as DNA, cell membranes, and other vital cellular components.
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PMID:Evaluation of some antioxidant enzymes in lung carcinoma tissue. 863 62

The relationship between various bioceramics used in surgical implantation and inflammatory cellular response has not been fully elucidated. The objective of this study was to investigate the effect of various biomedical ceramics such as tricalcium phosphate (TCP), hydroxyapatite (HA), and aluminum-calcium-phosphorous oxide (ALCAP) on the adherence and viability of human monocyte and monocyte derived macrophages in vitro. The monocytes were isolated from human peripheral blood and seeded at a density of 5 x 10(5) cells/well according to standard laboratory procedures. Cells were considered macrophages after remaining in culture for 24 hours. Cells were then plated in each microtiter well loaded with ceramic capsules (HA, TCP and ALCAP) and buffered control. At the end of 1, 2, 3, and 7 days the viability and cell number of monocyte or monocyte derived macrophages were determined using an established assay. Cell number was determined in control wells with known amounts of cell number, a standard curve was generated by plotting absorbance units versus cell number. Biochemical analysis was performed on the aliquots obtained from the experimental and control wells at the end of each phase of the investigation. The data from this experiment suggest that: (I) monocytes and macrophages are capable of adhering to the surface of HA, TCP and ALCAP in an in vitro environment for over a 7 day period. (II) Long term incubation of ceramic capsules with macrophages revealed that the cells experienced gradual disassociation phenomenon with a greater number of cell detachment seen in the ALCAP contained wells. (III) SEM analysis of representative capsules demonstrated that there is an increase in the number of micropores on the surface of the materials after contacting a cellular environment. This observation suggest that the material surface has been modified (TCP > HA = ALCAP). (IV) Biochemical analysis of aliquots at the end of each phase showed a significant change (P < 0.05) in the activity of catalase and superoxide dismutase (SOD). Information obtained from this study provided new insights on the interrelationship between bioceramics and the possible cell response during chronic inflammation at the site of implantation.
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PMID:The effect of HA, TCP and ALCAP bioceramic capsules on the viability of human monocyte and monocyte derived macrophages. 867 93

Increased permeability is an early and universal response of the vasculature to radiation injury, yet the biological basis of this reaction is poorly understood. The present study determined the time course and the dose-response relationship of radiation-induced hyperpermeability in cultured bovine pulmonary artery endothelial (BPAE) cells. BPAE cells were grown to a confluent monolayer on microcarrier beads, and column chromatography methods were used to evaluate permeability to two low molecular weight compounds: sodium fluorescein (NaFlsc, mol. wt. = 342) and cyanocobalamin (B12, mol. wt. = 1355). This is a novel in vitro model to study mechanisms and modifiers of radiation-induced permeability of endothelial cells under flow conditions using nonradioactive tracers. Cell-covered beads were exposed to a single dose of 10 Gy Of 137Cs gamma rays and placed in the column, and permeability was measured every 30 min for 3 h. There was a time-dependent increase in permeability to both tracers, reaching significance by 2 h. Increased permeability was accompanied by perturbations in F-actin distribution in the BPAE cells as determined by rhodamine-phalloidin fluorescence microscopy. Neither catalase nor captopril ameliorated this hyperpermeability, but dibutyryl cAMP partially prevented it. At 3 h after 0, 1, 2, 5 and 10 Gy irradiation, permeability values of 11.8 +/- 2.1, 13.9 +/- 2.2, 20.9 +/- 3.6, 24.8 +/- 2.8 and 27.2 +/- 3.3 (10(-5) cm/s, +/- SEM), respectively, were observed using NaFlsc. The increase was significant (P < 0.05) at 2 Gy or higher. Permeability to B12 was significantly elevated after 5 or 10 Gy. These results suggest that permeability of endothelial cells to low molecular weight solutes increases within 3 h after therapeutic doses of radiation, and that cAMP ameliorates this response.
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PMID:Dose-response effects of radiation on the permeability of endothelial cells in culture. 875 11

Growth factor receptors transmit biological signals for the stimulation of cell growth in vitro and in vivo and their autocrine stimulation may be involved in tumorigenesis. It is therefore, of great value to understand receptor reactions in response to ultraviolet (UV) light which certain normal human cells are invaribly exposed to during their growth cycle. UV irradiation has recently been shown to deplete antioxidant enzymes in human skin. The aims of the present study were a) to compare the lateral mobility of epidermal growth factor receptors (EGF-R) in cultured human keratinocytes and human foreskin fibroblasts, b) to investigate effects of ultraviolet B radiation on the mobility of EGF-R in these cells, and c) study the response of EGF-R on addition of antioxidant enzymes. The epidermal growth factor receptors were labeled with rhodaminated EGF, the lateral diffusion was determined and the fraction of mobile EGF-R assessed with the fluorescence recovery after photobleaching (FRAP). We found that human keratinocytes display a higher basal level of EGF-R mobility than human skin fibroblasts, viz. with diffusion coefficients (D +/- standard error of the mean, SEM) of 4.2 +/- 0.2 x 10(-10) cm2/s, and 1.8 +/- 0.2 x 10(-10) cm2/s, respectively. UVB-irradiated fibroblasts showed an almost four-fold increase in the diffusion coefficient; D was 6.3 +/- 0.3 x 10(-10) cm2/s. The keratinocytes, however, displayed no significant increase in receptor diffusion after irradiation; D was 5.1 +/- 0.8 x 10(-10) cm2/s. In both cell types the percentage of EGF-R fluorescence recovery after photobleaching, i.e. the fraction of mobile receptors, was significantly increased after irradiation. In keratinocytes it increased from 69% before irradiation to 78% after irradiation. Analogous figures for fibroblasts were 61% and 73%. The effect of UVB on fibroblast receptors was abolished by prior addition of superoxide dismutase (SOD) and catalase (CAT). It is concluded that UVB radiation of fibroblasts and keratinocytes can affect their biophysical properties of EGF-R. The finding that addition of antioxidant enzymes prevented the UVB effect in fibroblasts may indicate the involvement of reactive oxygen metabolites.
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PMID:UVB radiation affects the mobility of epidermal growth factor receptors in human keratinocytes and fibroblasts. 884 73

A model of cardiac dysfunction induced by reactive oxygen species (ROS) was established by adding hydrogen peroxide (H2O2) to the perfusate of isolated, Langendorff-perfused rat hearts, and the mechanism of functional injury was investigated. The following groups were included: 1 (n = 7), control perfusion; 2 (n = 11), perfusion with H2O2 (180 mumol 1(-1) for 10 min followed by recovery for 50 min; 3 (n = 4), control perfusion with N-acetylcysteine (NAC, 100 mumol 1(-1); 4 (n = 7), perfusion with H2O2 and NAC; 5 (n = 4), control perfusion with thiourea (15 mmol 1(-1), 6 (n = 7), H2O2 and thiourea together; 7 (n = 4), control perfusion with catalase (150 U ml-1); 8 (n = 7), catalase and H2O2, 9 (n = 4), control perfusion with deferoxamine (5 mmol 1(-1); and 10 (n = 7), deferoxamine and H2O2. coronary flow (CF), left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), and heart rate (HR) were measured. All values are mean +/- SEM. When given alone, catalase, thiourea, NAC and deferoxamine did not influence left ventricular pressures, but NAC, catalase and thiourea increased CF. H2O2 increased CF (maximum 146 +/- 6% of baseline value after 5 min, p < 0.001 compared to group 1), decreased LVDP (minimum 14 +/- 5% of baseline value after 10 min, p < 0.0004), and increased LVEDP (from 0 mmHg to a maximum of 54 +/- 7 mmHg after 5 min recovery, p < 0.0003). All these changes gradually reversed during recovery. Catalase and thiourea both inhibited the H2O2-induced effects, but catalase inhibition was more complete. Neither NAC nor deferoxamine had any effect on H2O2-induced cardiac dysfunction. In conclusion, H2O2 perfusion is a convenient and reversible model of ROS-induced functional injury to isolated rat hearts. H2O2, rather than the hydroxyl radical, seems to be the main injurious ROS in this model.
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PMID:Perfusing isolated rat hearts with hydrogen peroxide: an experimental model of cardiac dysfunction caused by reactive oxygen species. 886 66

An increase in antioxidant enzyme activity after acute exercise and exercise training have been reported by many investigators including our laboratory. This study was undertaken in order to determine whether an increase in activity of superoxide dismutase (MnSOD and CuZnSOD), catalase (CAT) and glutathione peroxidase (GSH-Px) during exercise training was associated with the increased levels of respective mRNAs. Male Fisher-344 rats (age 77 weeks) were given exercise training for 9 weeks on the treadmill. Enzyme activity and mRNA's were measured in the heart tissue 23 hr after stopping exercise training. The heart tissues of exercised and sedentary control rats were used to isolate mRNAs encoding MnSOD, CuZnSOD, CAT and GSH-Px by northern blotting experiments. The intensities of mRNA bands were measured by densitometric scanning of the autoradiograms. Northern blot for tubulin was used to normalize the respective intensities. Compared to sedentary controls, the level of mRNAs of enzymes MnSOD, CAT and GSH-Px were found to increase by 126 +/- 5, 133 +/- 6, and 138 +/- 5 percent of sedentary control (mean +/- SEM) respectively, due to exercise training. Corresponding values for these enzyme activity were 153 +/- 19%, 255 +/- 7%, 133 +/- 2% of sedentary control. These results suggest that post-translational modification of these enzyme activity increased in response to exercise training more than increased transcription in aged rats.
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PMID:Comparative effects of exercise training on transcription of antioxidant enzyme and the activity in old rat heart. 895 Jan 34

The objective of this study was to examine the effects of reactive oxygen species (ROS) on bovine sperm function and on the developmental competence of in vitro-matured bovine oocytes. In a first series of experiments, spermatozoa were exposed to ROS generated through the use of the hypoxanthine-xanthine oxidase system +/- catalase prior to the conduct of in vitro fertilization (IVF). Reactive oxygen species exposure reduced significantly (P < 0.001) the rates of oocyte penetration (control: 56% +/- 4 SEM; ROS: 16 +/- 2-23% +/- 7 SEM), and this effect was reversed by adding catalase (ROS+catalase: 67% +/- 0.3 SEM). During IVF, addition of superoxide dismutase (SOD: 1, 10, or 100 U/ml) had no effect on penetration rates. However, increasing concentrations of catalase (0.1 or 1 mg/ml) reduced these rates significantly (control: 70% +/- 3 SEM; treated: 45% +/- 5 and 1% +/- 1 SEM; P < 0.001). In a second series of experiments, when oocytes were matured in vitro in the presence of exogenous antioxidants (SOD: 10, 100, or 1000 U/ml; beta-mercaptoethanol: 0.01, 0.1, or 0.5 mM; ascorbic acid: 0.05 mg/ml), the developmental competence of the oocytes after IVF was not significantly improved. On the other hand, presumed production of ROS using the hypoxanthine-xanthine system at the beginning of the in vitro maturation period did improve subsequent developmental competence of the oocytes under some conditions and when catalase was present (control: 14% +/- 4 SEM and treated: 23% +/- 9 and 27% +/- 8 SEM; P < 0.05). These observations demonstrate that ROS may be beneficial to gamete function under specific conditions.
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PMID:The impact of reactive oxygen species on bovine sperm fertilizing ability and oocyte maturation. 928 60

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