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C Deby

Publications and source records attributed to C Deby.

At least 19 recordsLinked to original sources
PubMed1996

Bactericidal activity against Pseudomonas aeruginosa is acquired by cultured human monocyte-derived macrophages after uptake of myeloperoxidase.

Myeloperoxidase (MPO) is an enzyme located within polymorphonuclear neutrophils capable of producing cytotoxic oxidant species that are particularly active against bacteria with polysaccharide capsules. Pseudomonas aeruginosa (10(6) bacteria per 1ml) are killed within 1 h in vitro by a MPO/H2O2/C1- system (48mU=132ng of MPO). The question arose as to whether human macrophages would acquire cytotoxic activity when loaded with this enzyme. Monocytes were therefore isolated from human blood and cultured for up to ten days to induce maturation to macrophages. These cells lost endogenous MPO within five days while H2O2 production in response to stimulation by phorbol myristate acetate (10(-6)M) decreased to 23% within ten days. On the other hand, their capacity to take up exogenous MPO increased fourfold from day three to day ten. Human macrophages cultured from eight days (when both H2O2 production and MPO uptake were sufficient) were therefore used to study the effects of MPO uptake on cytocidal activity against Pseudomonas aeruginosa. After a 1 h MPO loading period, macrophages (5X10(5) cells per ml) were incubated in the presence of bacteria (0.5 to 2X10(6) bacteria per ml) for 2 h at 37 degrees C. At a bacteria/macrophage ratio of 1, only 34.8+/-7.0% of bacteria survived (compared to killing by non-loaded macrophages), while 74.4+/-9.3% survived at a ratio of 4. From these results, we conclude that loading macrophages with exogenous MPO could enhance their microbicidal activity, suggesting a potentially useful therapeutic application.

Blood Bactericidal Activity↗
PubMed1996

Experimental model for the study by chemiluminescence of the activation of isolated equine leucocytes.

The activation of human polymorphonuclear leucocytes (the respiratory burst) can be studied by measuring their chemiluminescent response. This technique was adapted to equine leucocytes to investigate the effects of cell number, activator concentration, enhancers of chemiluminescence, pH, temperature and inhibitors. Leucocytes were isolated from citrated blood from healthy horses and chemiluminescence was measured with a Bio-Orbit luminometer sensitive to 900 nm light. The optimal cell density for the maximal chemiluminescent response ranged from 10(6) to 10(7) leucocytes 600 microliters-1. Chemiluminescence increased as a function of temperature, and the concentrations of luminol, lucigenin and phorbol myristate acetate (PMA), and was pH related (optimal pH value = 8.0 for lucigenin and 8.5 for luminol). The inhibition of chemiluminescence by 5 x 10(-5) M azide was 88 per cent for luminol and 37 per cent for lucigenin. Superoxide dismutase (100 IU) totally inhibited the chemiluminescence response. Approximately 30 per cent variability in chemiluminescence was observed under the same assay conditions, depending on the origin of the leucocytes. Based on these results, the conditions selected for the measurement of equine leucocyte chemiluminescence were: 10(6) to 10(7) leucocytes 600 microliters-1, 1 x 10(-6)M PMA, 1 mM luminol or 0.4 mM lucigenin, physiological pH (7.4) and physiological temperature (37.8 degrees C). These conditions were similar to those used for measuring the chemiluminescent response of human leucocytes.

Acridines↗
PubMed1996

Myocellular enzyme leakage, polymorphonuclear neutrophil activation and delayed onset muscle soreness induced by isokinetic eccentric exercise.

To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product prostaglandin E2 (PGE2). 10 healthy male subjects were submitted to eccentric and concentric isokinetic exercises on a Kin Trex device at 60 degrees/s angular velocity. Exercise consisted of 8 stages of 5 maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases. There was an interval of at least 30 days between eccentric and concentric testing, and the order of the two exercise sessions was randomly assigned. The subjective presence and intensity of DOMS was evaluated using a visual analogue scale, immediately, following 24 h and 48 h after each test. Five blood samples were drawn from an antecubital vein: at rest before exercise, immediately after, after 30 min recovery, 24 h and 48 h after the tests. The magnitude of the acute inflammatory response to exercise was assessed by measuring plasma levels of polymorphonuclear elastase ([EL]), myeloperoxidase ([MPO]) and PGE2 ([PGE2]). Using two way analysis of variance, it appeared that only eccentric exercise significantly increased [EL] and DOMS, especially of the hamstring muscles. Furthermore, a significant decrease in eccentric peak torque of this muscle group only was observed on day 2 after eccentric work (- 21%; P < 0.002). Serum activity of creatine kinase and serum concentration of myoglobin increased significantly 24 and 48 h after both exercise tests. However, these variables reached significantly higher values following eccentric contractions 48 h after exercise. Mean [PGE2] in the two exercise modes remained unchanged over time and were practically equal at each time point. On the basis of these findings, we conclude that the magnitude of polymorphonuclear (PMN) activation, muscle damage, and DOMS are greater after eccentric than after concentric muscle contractions. However, the hypothesized interplay between muscle damage, increased PGE2 production, DOMS sensations, and reduced isokinetic muscle performance was not substantiated by the present results.

Adult↗
PubMed1996

Effect of propofol on in vitro lipid peroxidation induced by different free radical generating systems: a comparison with vitamin E.

Propofol has been reported to have antioxidant properties and to inhibit lipid peroxidation. In this study, we examined the ability of propofol to inhibit lipid peroxidation induced by three free radical systems (hydroxyl, ferryl, and oxo-ferryl radicals), and we compared the effect of propofol with that of vitamin E, an endogenous antioxidant. Lipid peroxidation was induced by exposing a linoleic acid emulsion to either water gamma radiation, a ferrous iron-ascorbate solution, or human hemoglobin, generating the hydroxyl, ferryl, and oxo-ferryl radicals, respectively. Each experiment was performed in triplicate with and without propofol or vitamin E at concentrations between 10(-5) and 10(-4) M. Lipid peroxidation was quantified by gas chromatography measurement of the pentane released (nmoles) from lipid decomposition. In each condition, a significant dose-response relationship was found between the release of pentane and the concentration of either propofol or vitamin E. The antioxidant activities of both agents were similar but significantly higher against the hydroxyl than the ferryl and oxo-ferryl radicals. The study suggests that propofol could be beneficial as an anesthetic or sedative drug in patients presenting pathologies associated with free radical reactions.

Anesthetics, Intravenous↗
PubMed1995

Diaspirin crosslinked hemoglobin (DCLHb): absence of increased free radical generation following administration in a rabbit model of renal ischemia and reperfusion.

In control rabbits, a renal ischemia of 60 min followed by 10 min of reperfusion resulted in an enhanced free radical production in cortical tissue, as assessed by a significant decrease of free glutathione (42%), protein-bound GSH (17%), and vitamin E (49%). In contrast, catalase or glutathione peroxidase activities were not affected by these experimental conditions. Free radical production in this model was also measured directly using electron spin resonance (ESR) spectroscopy associated with a PBN (alpha-phenyl N-tert-butyl-nitrone) spin trap agent in the venous blood arising from the ischemic kidney. The signal consisted of a triplet of doublets. In contrast, no signal could be detected in control blood samples taken prior to inducing ischemia. The burst of free radical production occurred in the early phase after restoration of flow in the kidneys rendered ischemic, as evidenced by a signal of weak intensity which generally appeared within the third minute after reperfusion and progressively increased to form a well-defined asymmetric signal following 10 min of reperfusion. The precise nature of free radicals trapped by the PBN agent remains, however, to be elucidated, but analysis of the coupling constants (aN = 14.5-15 G; a beta H = 2.5-3 G) and asymmetry of the central doublets suggests that the ESR signal may arise from a nitorxy-radical adduct resulting from the spin trapping by PBN of both oxygen- or carbon-centered radicals of lipid origin. As evidenced by both direct and indirect measurements, exchange of rabbit blood immediately after inducing renal ischemia with 30 ml/kg of Diaspirin Crosslinked Hemoglobin (7.5 g/dl in lactated electrolyte) or human serum albumin (7.5 g/dl in lactated electrolyte) did not exacerbate free radical production mediated by an ischemia reperfusion phenomenon, a typical situation found in a resuscitation setting.

Animals↗
PubMed1995

Anti-inflammatory properties of copper, gold and silver, individually and as mixtures.

It has been previously demonstrated that the mixture of Cu, Au and Ag impaired significantly the clinical and biochemical disorders induced by adjuvant arthritis in the rat. The efficiency of this mixture and of each component was tested on the same animal model. Treated rats were injected daily with either 22.8 micrograms of copper gluconate, 0.2 micrograms of gold thioglucose, 6.8 micrograms of silver proteinate or the blended solution over a period of 29 d. The treatment with the one component solutions was found to have a little or no effect on the plasma levels of fibrinogen, haptoglobin, ceruloplasmin, prostaglandin E2, thromboxane B2, total proteins, Zn, Cu, Mn, Se, Co and Ni, and no significant decrease was observed in the paw oedema resulting from the Freund's adjuvant injection. The treatment with the mixture had a significant preventive effect. Therefore it seems that the administration of low doses of each of the three trace elements have no anti-rheumatic property in the rat. The results indicate an enhanced effect of the metal mixture in the model studied.

Animals↗
PubMed1994

Are similar inflammatory factors involved in strenuous exercise and sepsis?

An increasing body of data suggest that strenuous exercise triggers an inflammatory response having some similarity with those occurring in sepsis. Indices of this inflammatory response to exercise (IRE) especially include leukocytosis, release of inflammatory mediators and acute phase reactants, tissue damage, priming of various white blood cell lines, production of free radicals; activation of complement, coagulation and fibrinolytic cascades. Inflammatory responses to strenuous exercise and sepsis could in part be due to the release of endotoxin in blood as common triggering factor, but it seems that tissue damage and/or contact system activation are more important triggering mechanisms in exercising subjects. While the magnitude and duration of cellular and humoral changes associated with IRE are quite different from those observed in sepsis, recent human studies suggested that chronic and/or excessive IRE could have adverse effects. Among the possible consequences of acute and chronic IRE are delayed onset muscular soreness and loss of force, cardiovascular complications, intravascular hemolysis, hypoferraemia and increased susceptibility to infection.

Blood Coagulation↗
PubMed1994

Anaphylatoxin C5a production during short-term submaximal dynamic exercise in man.

We studied the effects of short-term submaximal exercise on the plasma levels of myeloperoxidase ([MPO]) and C5a anaphylatoxin ([C5a]), taken as specific markers of polymorphonuclear neutrophil (PMN) and complement activation, respectively. Eleven young, healthy male volunteers were subjected to a constant-load concentric exercise on a cycle ergometer (20 min at 80% maximal oxygen uptake). Mean resting MPO and C5a concentrations were 437 +/- 113 and 0.47 +/- 0.21 ng/ml, respectively. During exercise, [MPO] and [C5a] increased significantly (p < 0.001) towards respective peak values of 649 +/- 131 and 1.3 +/- 0.6 ng/ml. A rapid decrease of both [MPO] and [C5a] was observed during recovery. The similar time course of [MPO] and [C5a] changes and the highly significant relationship between these two variables (r = 0.651; p < 0.001) argues for the possible involvement of the complement anaphylatoxin C5a in the process of PMN degranulation. During exercise, the number of circulating PMN increased (+80%; p < 0.001) and remained practically unchanged up to 20 minutes of recovery. As [MPO] and PMN count were not significantly related (r = 0.2; p < 0.1), we concluded that the activation of PMN was independent of their mobilization.

Adult↗
PubMed1993

Evidence for free radical formation during human kidney transplantation.

Fourteen patients undergoing kidney transplantation were studied for evidence of the production of free radicals as assessed by the measurement of vitamin E (an index of lipid peroxidation) and of myeloperoxidase (a marker of neutrophil activation) in the systemic blood. Early (2 min) and late revascularization (30 min) of the kidney were respectively associated with a significant decrease of 35.5 and 40% of the initial level of plasma vitamin E. This consumption paralleled to the decrease of the vitamin E/total lipids ratio, a better indicator of vitamin E status. Heparin administration preceding renal artery clamping resulted in a twofold significant increase of baseline plasma myeloperoxidase (MPO) level (523 +/- 214 ng/ml). At kidney reperfusion, MPO concentration rose again and reached a maximum value of 1,653 +/- 882 ng/ml, indicating the presence of considerable neutrophil activation. A return to the baseline value was observed after 30 min of reperfusion. A short discussion about the possible origin of this MPO increase is given. Taken together, these data strongly suggest that free radical production, leading to lipid peroxidation phenomena, can occur within the early phase of kidney revascularization. Preliminary data using electron spin resonance with the spin-trapping technique strengthen this hypothesis.

Adult↗
PubMed1993

Production of active oxygen species by isolated human chondrocytes.

The ability of isolated human chondrocytes to produce active oxygen species has been investigated. The two methods for determining H2O2 and hydroxyl radicals (.OH) production were, by a fluorimetric method (production of dichlorofluorescein from a precursor in the presence of horseradish peroxidase and H2O2) and by a chromatographic method (measurement of ethylene production from gamma-methiol-keto-butyric acid after .OH attack). Chondrocytes were tested, both with and without activation by phorbol myristate acetate (PMA: 10(-6) M), in the presence of Ca2+ (1 x 10(-4) M) and Mg2+ (2 x 10(-4) M) or after variable periods of anoxia under nitrogen (4 to 12 h) followed by reoxygenation (with 95% O2, 5% CO2). Under these experimental conditions, the PMA-excited chondrocytes produced from 80 to 180 nmol of hydrogen peroxide per 1 x 10(6) cells and chondrocytes subjected to anoxia-reoxygenation produced up to 1700 nmol H2O2 per 1 x 10(6) cells. The hydroxyl radical production by PMA or anoxia-reoxygenation excited cells reached 600% of the production of non-excited cells and 1300% when they were subjected to successive stimulations by PMA and anoxia-reoxygenation. The possible pathological significance of these observations is discussed. The results indicate that stimulated human chondrocytes are capable of producing active oxygen species which could play a major role in joint inflammation and cartilage damage.

Adolescent↗
PubMed1993

In vivo free radical production after cross-clamping and reperfusion of the renal artery in the rabbit.

Postischaemic reperfusion injury is often attributed to the generation of oxygenated free radicals which may subsequently promote lipid peroxidation in cell membranes. Electron paramagnetic resonance spectroscopy in association with the spin trap molecule alpha-phenyl-N-tert-butyl-nitrone allowed direct confirmation of lipid free radical production after renal ischaemia-reperfusion in an in vivo rabbit model. A 60-min period of ischaemia followed by reperfusion caused free radical production twofold greater than after 15 min of ischaemia. Glutathione and alpha-tocopherol have been measured in renal tissue, as indirect markers of lipid peroxidation. After 15 min of ischaemia followed by 10 min of reperfusion, the mean(s.e.m.) glutathione content of the ischaemic kidney was slightly but significantly reduced by 11.9(2.5)% (P < 0.003). The content of alpha-tocopherol was unchanged. However, 10 min of reperfusion following 60 min of ischaemia led to significant decrease in mean(s.e.m.) content of both glutathione (30.4(3.7)%) (2.23(0.2) versus 3.14(0.18) mumol/g wet tissue, P < 0.001) and alpha-tocopherol (46.1(7.8)%) (0.57(0.10) versus 1.09(0.14) micrograms/g wet tissue, P < 0.001) when compared to the control kidney. Under these experimental conditions, desferrioxamine (15 mg/kg administered intravenously before inducing ischaemia), a drug known to limit free radical production, significantly limited the decrease of alpha-tocopherol to 20.8(6.4)% (0.83(0.08) versus 1.05(0.04) micrograms/g wet tissue, P < 0.05), but did not prevent glutathione consumption in the reperfused kidney.

Animals↗
PubMed1992

Active oxygen species, articular inflammation and cartilage damage.

Rheumatoid arthritis and osteoarthritis are age-related diseases, in which degenerative changes (arthrosis) and superimposed inflammatory reactions (arthritis) lead to progressive destruction of the joints. Active oxygen species derived from various sources play a role in this process, which may be influenced by appropriate treatment with antioxidants and free radical scavengers.

Aging↗
PubMed1992

Plasma levels of polymorphonuclear elastase and myeloperoxidase after uphill walking and downhill running at similar energy cost.

This study was designed to compare the effects of eccentric and concentric exercises on blood polymorphonuclear neutrophil count (nPMN) and plasma levels of myeloperoxidase ([MPO]) and elastase ([EL]) used as markers of neutrophil (PMN) activation. Ten healthy male subjects underwent 2 periods of exercise of 20 min duration each at 60% VO2max on an inclined treadmill. They initially walked up a 5% grade (UW). Ten days later they ran downhill on a 20% grade (RD). Blood samples were collected 10 min before and immediately after exercise. A postexercise sample was drawn after 20 min recovery. Both exercise bouts were accompanied by a similar and significant (p < 0.01) increase of 33% in nPMN above resting values. Baseline nPMN values were reached after 20 min recovery. There were no significant changes in [MPO] and [EL] following UW. In contrast, RD was followed by significant increases (p < 0.001) in [MPO] (+97%) and [EL] (+70%) above resting levels. While [MPO] returned to its pre-exercise level after 20 min recovery, [EL] remained significantly elevated (p < 0.05). These results clearly demonstrate the importance of the eccentric component of muscle contraction in exercise-induced PMN activation.

Adolescent↗
PubMed1991

Spectral and enzymatic properties of human recombinant myeloperoxidase: comparison with the mature enzyme.

Human recombinant myeloperoxidase (recMPO), purified from an engineered Chinese hamster ovary (CHO) cell line, has been characterized and compared to the mature enzyme isolated from polymorphonuclear leukocytes. Both molecules appear essentially similar in physicochemical enzymatic terms according to the following observations. 1. The unprocessed recombinant protein displays the characteristic light absorption spectra of ferric mature MPO and exhibits its typical spectral changes in the presence of dithionite or hydrogen peroxide. 2. The addition of 14C-labeled 5-aminolevulinic acid, a heme precursor, to the culture medium of recombinant CHO cells yields labeled recMPO, indicating the presence of a heme-like structure in the molecule. 3. Like mature MPO, recMPO has a peroxidatic activity and catalyzes the oxidation of chloride ions in the presence of hydrogen peroxide, producing hypochlorous acid as measured by the monochlorodimedon assay. For both enzymes, the chlorinating activity optimally occurs around pH 5.0 at about 100 microM of hydrogen peroxide and is strongly inhibited by methimazole. 4. Diethylpyrocarbonate significantly reduces the enzymatic activity of both molecules, suggesting that histidine residues may be of prime importance in the active site of the enzymes. 5. According to infrared spectroscopy data, both enzymes present a very similar secondary structure organization. In conclusion, the data suggest that the processing of the precursor enzyme (recMPO) into the mature form occurs without major structural and functional consequences.

Animals↗
PubMed1991

Self-labeling of human polymorphonuclear leucocyte myeloperoxidase with 125iodine.

In order to obtain a radioimmunoassay (RIA) technique for the measurement of human plasma myeloperoxidase (MPO), we purified the enzyme from polymorphonuclear granulocytes (neutrophils), and compared three methods of labeling it with 125Iodine:chloramine T, lactoperoxidase, and an original technique of 'self labeling' based on the ability of the enzyme to oxidize and bind 125I in the presence of H2O2. The chloramine T technique produced a degraded protein, as well shown by a high non-specific binding of tracer to antibody. The lactoperoxidase technique did not succeed in labeling MPO with an adequate specific activity. In contrast, the self-labeling method gave a stable tracer with a specific activity of 23 microCi/micrograms MPO (85 MBq), a satisfactory level of immunoreactivity, and a low-specific binding (less than or equal to 3%). After labeling, purification of tracer was achieved by gel filtration chromatography in phosphate buffer (0.05 M; pH7) to which 0.1% poly-L-lysine was added. The labeled molecule remained stable for 40 days and could be used for RIA with a polyclonal antibody raised in rabbits.

Chloramines↗
PubMed1991

Fast double antibody radioimmunoassay of human granulocyte myeloperoxidase and its application to plasma.

The haem enzyme myeloperoxidase (MPO) (EC 1.11.1.7) with a spectral A430/A280 ratio greater than 0.7 and a specific activity of 125 U/mg was purified from isolated human neutrophils. To obtain a radioimmunoassay (RIA) for this enzyme, a specific antiserum against human neutrophil MPO was raised in rabbits and used at an initial dilution of 1/10,000. MPO labelled with 125iodine by a technique of self-labelling in the presence of H2O2, had a specific activity of 24 mCi/mg. After incubation at room temperature (2 h) and separation by double antibody precipitation in the presence of polyethylene glycol, the sensitivity of the RIA was 21 ng/ml. The RIA showed good precision and accuracy with intra- and interassay coefficients of variation of less than 7% for MPO concentrations ranging from 100 to 800 ng/ml, and satisfactory recoveries of known amounts of exogenous MPO in plasma. For the measurement of MPO in blood, the best sampling technique was to collect blood into EDTA. Rapid centrifugation (within 20 min) was necessary for blood collected into heparin. Mean MPO values in normal individuals were 340 +/- 98 ng/ml in EDTA plasma (n = 152) and 332 +/- 82 ng/ml in heparinized plasma (n = 34). When MPO was measured 12-6 h after injury in critically ill patients high values (above 1000 ng/ml) were found in 6/15 patients with multiple injuries. In patients with sepsis (n = 22), MPO values were always above 1000 ng/ml.

Animals↗