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At least 397 records · Page 22Linked to original sources
PubMed2006

Porphyrin-induced photogeneration of hydrogen peroxide determined using the luminol chemiluminescence method in aqueous solution: A structure-activity relationship study related to the aggregation of porphyrin.

A luminol chemiluminescence method was used to evaluate the porphyrin-induced photogeneration of hydrogen peroxide (H2O2). This method enabled us to detect H202 in the presence of a high concentration of porphyrin, which was not possible using conventional colorimetry. The limit of detection was about 1 microM. We compared the ability to generate H2O2, using uroporphyrin (UP), hexacarboxylporphyrin (HCP), coproporphyrin (CP), hematoporphyrin (HP), mesoporphyrin (MP), and protoporphyrin (PP). The amount of H2O2 photoproduced was strongly related to the state of the porphyrin in the aqueous solution. UP and HCP, which existed predominantly in a monomeric form, had a good ability to produce H2O2. HP and MP, existing as dimers, showed weak activity. CP, forming a mixture of monomer and dimer, had a moderate ability to produce H2O2. PP, which was highly aggregated, had a good ability. These results demonstrated that the efficiency of porphyrins to produce H2O2 was strongly dependent on their aggregated form, and the dimer suppressed the production of H2O2.

Colorimetry↗
PubMed1989

Correlation between neutrophil superoxide formation, luminol-augmented chemiluminescence and intracellular Ca2+ levels upon stimulation with leukotriene B4, formylpeptide and phorbolester.

When neutrophils were stimulated with leukotriene B4 (LTB4) .O2- -production and elevation of intracellular Ca2+ were initiated more rapidly than after stimulation with N-formyl-methionyl-leucyl-phenylalanine. Phorbol myristate acetate (PMA) induced a substantially more protracted superoxide (.O-2) production. Luminol augmented chemiluminescence (LCL) reflected the kinetic characteristics accurately. The primary distinguishing attribute of LTB4-induced responses were an initial high rate of activation and a rapid termination. Thus, LTB4-induced neutrophil Ca2+-inflow and .O2- -formation may be initiated by mechanisms similar in part to those for formylpeptides; however it does not possess the ability to maintain this activation. The kinetic properties of neutrophil activation may be studied with LCL, irrespective of the exact nature of the LCL-generating oxidants formed by neutrophils.

Calcium↗
PubMed1993

Luminol enhanced Fc-receptor dependent chemiluminescence from peripheral PMN cells. A methodological study.

Maximal luminol enhanced chemiluminescence (CL) of PMN cells after Fc-gamma-receptor stimulation is a way to study the cell activity in connection with phagocytic function. Optimal conditions for such a method were elaborated for practical clinical use. After blood sampling and gentle mixing the blood sample was allowed to stand at +20 degrees C for not more than 1 h. The PMN cells prepared at +20 degrees C were washed at +4 degrees C with a phosphate buffer containing human serum albumin. A gentle lysis of the red blood cells with NH4Cl solution reduced the number of red cells sufficiently not to interfere with the CL. Important factors for the precision of the method were reproducible amounts of bacteria and a reproducible mixing of the particles during the CL analysis. The method had a variation (CV) of 10-15% in healthy individuals.

Adult↗
PubMed1991

Aluminum salts stimulate luminol-enhanced chemiluminescence production by human neutrophils.

Aluminum intoxication is currently thought to play a major role in the development of Alzheimer's disease and in certain pathologic manifestations seen during long-term hemodialysis and aging. The hypothesis that aluminum toxicity is mediated via an increased free radical production was tested by studying the effects of two aluminum and five other metallic compounds on the production of luminol-enhanced chemiluminescence (LECL) by human neutrophils. AlCl3, Al2(SO4)3 and FeCl3 were found to stimulate LECL production by human neutrophils whereas FeCl2, CuCl, CuCl2, AuCl3 were inactive. Metal chelators such as Desferal, EDTA and DETAPA suppressed aluminum-induced stimulation and depressed cell-dependent LECL below basal levels. Sodium azide and Cytochalasin B greatly depressed both basal and aluminum-induced stimulation of LECL production, suggesting that, in this system, most of this stimulation was due to myeloperoxidase. These results suggest that high tissue aluminum concentrations may induce cell-tissue lesions by stimulating local production or release of mediators of tissue damage.

Alum Compounds↗
PubMed1998

Nitric oxide production in human macrophagic cells phagocytizing opsonized zymosan: direct characterization by measurement of the luminol dependent chemiluminescence.

When differentiated into mature macrophages by the combination of all-trans retinoic acid and 1,25-dihydroxyvitamin D3, the human promonocytic cell lines U937 and THP-1 expressed inducible nitric oxide synthase (iNOS) transcripts. During their differentiation, the cells acquired the capacity to produce not only superoxide anion (O2.-) but also nitric oxide (.NO) in response to IgG (or IgE)-opsonized zymosan. The inhibitors of the iNOS pathway, aminoguanidine and NG-monomethyl-L-arginine (L-NMMA), suppressed the production of .NO and enhanced the steady-state concentration of O2.- determined. Conversely, superoxide dismutase (SOD) scavenged the O2.- released and increased the .NO-derived nitrite concentration detected. These data suggested a possible interaction between O2.- and .NO. In differentiated U937 (or THP-1) cells, IgG or IgE-opsonized zymosan induced a strong time-dependent luminol-dependent chemiluminescence (LDCL), which was abrogated by SOD and partially inhibited by aminoguanidine or L-NMMA. Since the iNOS inhibitors did not directly scavenge O2.-, LDCL determination in the presence or absence of SOD and/or iNOS inhibitors demonstrated a concomitant production of O2.- and .NO. These radicals induced the formation of a .NO-derived product(s), probably peroxynitrite (ONOO-), which was required to elicit maximal LDCL. Finally, LDCL measurement provided a convenient tool to characterize iNOS triggering and demonstrated an interaction between NADPH oxidase and iNOS products in human macrophagic cells phagocytizing opsonized-zymosan. These findings show that in activated macrophages, iNOS activity can be involved in LDCL and support the debated hypothesis of iNOS participation to the microbicidal activity of human macrophages.

Calcitriol↗
PubMedDate not supplied

[Enhancement of luminol-dependent chemiluminescence in an aqueous NaCl/H2O2 solution by argon].

It was found that the bubbling of argon through NaCl/H2O2 aqueous solutions results in the development of intense sustained luminol-dependent chemiluminescence. Bubbling of nitrogen and air through similar solutions does not result in such effect. The relationship between argon-supported chemiluminescence and initial concentrations of NaCl and H2O2 is characterized by threshold effects. In NaCl/H2O2 solutions blown with argon, hypochlorite was found, indicating that argon intensifies the reaction of chloride oxidation with H2O2. It is suggested that the enhancement of this reaction in aqueous solutions saturated with argon is related to specific changes in the properties of water, which is a highly nonequilibrium system. Possible consequences of relatively high concentrations of argon in the atmosphere for the chemical processes that occur in aqueous systems and, in particular, living systems are discussed.

Argon↗
PubMed2000

[Effect of carbon disulfide on pyrogallol- luminol auto-oxidation chemiluminescence system and superoxide anion].

OBJECTIVE: To study the effect of carbon disulfide (CS(2)) on pyrogallol-luminol auto-oxidation chemiluminescence (PA-L) system and production of superoxide anion. METHODS: Luminescence dynamic curve of CS(2) and inhibition effect of superoxide dismutase (SOD) on intensity of chemiluminescence induced by CS(2) were studied with PA-L chemiluminescence system. RESULTS: Different concentrations of CS(2) (10, 40, 80 mg/ml) could enhance the emission intensity of chemiluminescence of PA-L system and delayed its peak time, with a significant dose-effect relationship, as compared with that of solvent ethanol. Peak of chemiluminescence induced by 80 mg/ml of CS(2) was higher than its background value without solvent ethanol. Chemiluminescence induced by CS(2) could be inhibited by SOD. CONCLUSION: CS(2) can generate superoxide anion in PA-L system and delay the peak time of chemiluminescence emission dynamic curve.

Anions↗
PubMed2002

Kinetic considerations on the electrogenerated luminescence of luminol at platinum electrode in the presence of hydrogen peroxide and oxygen.

The ECL behavior of the luminol/H2O2 and luminol/O2 systems was evaluated at Pt electrode by using different electroanalytical techniques such as chronoamperometry, cyclic and rotating disk electrode (RDE) voltammetry. Diffusive and kinetic parameters such as the diffusion coefficient of luminol, D, the number of exchanged electrons, n, and the apparent heterogeneous rate constant, kap, were determined in the maximum light emission conditions achieved at pH 11, at an electrode potential of 750 mV vs. SCE. The experimental order of reaction were determined from the relation between the reactant concentrations and the emitted light intensity.

Electrochemistry↗
PubMedDate not supplied

[Changes of luminol-dependent chemiluminescence of rabbit peripheral blood leukocytes during incubation with a specific allergen during the development of Arthus phenomenon].

The authors studied luminol-dependent chemiluminescence of rabbit peripheral blood leukocytes during the development of Arthus' phenomenon. Samples with a specific allergen were previously incubated. It was established that in this type of allergic reactions the intensity of leukocyte chemiluminescence was determined by the concentration of the allergen with which they were incubated. Small doses of the allergen stimulate and large doses inhibit it. The inhibition is linked with the direct effect of the allergen on the cells and is not attended with diminution of their viability.

Allergens↗
PubMed1992

Luminol-dependent chemiluminescence and the clinical course of multiple sclerosis.

The luminol-dependent chemiluminescence activity before and after the ACTH (Synacthen) treatment was investigated in multiple sclerosis patients and the dependence of the changes of chemiluminescence upon the disease course was evaluated. The tests were performed with granulocytes and monocytes in the presence or in the absence of autologous thrombocytes and, further, the activity of whole blood was tested. All the test were performed both without additional stimuli (spontaneous activity) and with opsonized zymosan. Of the parameters tested, only the spontaneous chemiluminescence activity of whole blood displayed an evidence of dependence on clinical course of the disease. In clinically improved patients a decrease of the whole blood chemiluminescence was found. Similar trend was observed in chemiluminescence of whole blood stimulated by zymosan and in spontaneous granulocyte activity in the presence of autologous thrombocytes. The results show that the whole blood chemiluminescence is decreased in improved patients and suggest that this decrease might be related to the leukocyte-thrombocyte interaction.

Adrenocorticotropic Hormone↗
PubMed1992

Potential use of luminol-dependent chemiluminescence for estimation of free radicals produced in hepatic microsomes and reconstituted cytochrome P-450 systems.

The evaluation of luminol-dependent chemiluminescence (CL) for determination of free radicals generated during the oxidative reactions of microsomal enzymes in microsomes and reconstituted systems has been studied. The results indicated that the CL not only depended on NADPH induction but also on intact cytochrome P-450 enzymes. The light emission signal was strongly scavenged by SOD with inhibition rate of 93%. A concentration of 24 mumol.L-1 cadmium acetate and 2.5 mumol.L-1 mercuric chloride also inhibited the signal significantly as compared with the control. The study of CL in detecting free radicals formed by biotransformation of 44 xenobiotics suggested that some of the compounds known as free radicals producing agents by bioactivation increased the light emission in cytochrome P-450 enzyme system, such as carbon tetrachloride, chloroform, tetrachloroethylene etc., the others forming toxic metabolites by biotransformation induced the CL in some cases, such as carbon disulfide, benzene, methyldursban, methylparathion etc. or decreased the light emission, such as parathion, aniline and polychlorinated byphenyls etc., and still others whose toxic effects have no relationship with their biotransformation had no influence or an inhibitory effect on the CL, such as aminopyrine, TOCP, and acrylamide. CL in the cytochrome P-450 enzyme system remained unchanged during the biotransformation of carcinogens such as diethylnitrosamine, dipropylnitrosamine and benzo(a)pyrene as compared with the control. However, 3-methylcholanthrene and dimethylnitrosamine had an enhancing effect on the CL, while 2-acetylaminofluorene and 2-aminoanthracene showed an inhibition to the signals.

Acetates↗
PubMed1992

[The opsonizing activity of the sera of hamadryas baboons immunized with a preparation of the outer membranes of Francisella tularensis (based on data from the luminol-dependent luminescence method)].

The opsonizing properties of sera obtained from hamadryas baboons immunized with the preparation of F. tularensis outer membranes (OM) were studied with the use of luminol-dependent chemiluminescence (CL) of whole blood. The immunization of monkeys with the OM preparation was shown to lead to the formation of functionally active antibodies possessing opsonizing properties with respect to virulent F. tularensis. Immune sera obtained from the animals immunized with live vaccine and from those immunized with OM preparation had no essential differences in their opsonizing properties. The level of IgG antibodies in immune sera correlated with the CL parameters of whole blood in the presence of F. tularensis opsonized with these sera. Increased CL of phagocytes observed after addition of bacteria and immune sera under test to whole blood taken from a nonimmune donor made it possible to evaluate the functional activity of antibodies, thus permitting its use as a test for the evaluation of the effectiveness of new vaccine preparations.

Animals↗
PubMed1990

[Glucose determination by using luminol].

The technique of glucose assay is based on measurements of the intensity of chemiluminescence resultant from glucose oxidation in an enzymic system containing glucose oxidase and peroxidase, as well as luminol in a saturating concentration. The sensitivity of chemiluminometric assay is by one order higher than the sensitivity of the routine colorimetric analysis. The suggested method is highly sensitive to glucose, does not involve the use of a carcinogenic stain, and may be used with a variety of the substrate concentrations: from 0.5 to 150 micrograms per sample.

Blood Glucose↗
PubMed1991

Luminol-dependent chemiluminiscence of monocytes and granulocytes in multiple sclerosis: the effect of autologous thrombocytes.

The luminol-dependent chemiluminiscence of monocytes and granulocytes and the effect of autologous thrombocytes upon the chemiluminiscence activity were investigated in multiple sclerosis patients, patients with other neurological diseases and healthy controls. The spontaneous monocyte chemiluminiscence was found to be significantly higher in multiple sclerosis patients than in healthy controls. However, no differences were found between multiple sclerosis patients and the group of other neurological diseases. Addition of autologous thrombocytes did not substantially alter both the spontaneous and the zymozan-stimulated monocyte chemiluminiscence. No significant differences in granulocyte spontaneous and stimulated chemiluminiscence were found between the multiple sclerosis patients and both control groups. In all multiple sclerosis patients the addition of autologous thrombocytes markedly depressed the spontaneous and stimulated granulocyte chemiluminiscence and a similar effect was observed in most of the patients with other neurological diseases. In healthy controls, the effect of autologous thrombocytes was rather more heterogenous and both a thrombocyte-dependent increase and a decrease of the granulocyte chemiluminiscence were found. The results suggest that platelets are able to suppress the granulocyte oxidative burst and that this scavenger mechanism can be activated in multiple sclerosis and some other neurological diseases.

Blood Platelets↗
PubMed1990

Anti-oxidant property of ethanolic extract of propolis (EEP) as evaluated by inhibiting the chemiluminescence oxidation of luminol.

Ethanolic extract of propolis (EEP) has remarkable medical properties, including protection of mice against gamma irradiation. Its anti-oxidative effect has been attributed to its radical scavenging ability. This manuscript demonstrates the ability of increasing amounts of EEP to inhibit luminol-H2O2 chemiluminescence in vitro, and suggests that its anti-oxidative capacity is partly due to its high content of flavonoids.

Antioxidants↗
PubMedDate not supplied

[A mechanism of luminol-dependent chemiluminescence of human serum in the presence of hydrogen peroxide].

Comparative role of proteins of the human blood plasma in luminol-dependent induction of chemiluminescence in the presence of hydrogen peroxide was studied. It was found that the largest contribution into chemiluminescence was made by the plasma fraction with the molecular mass 250 kD. Besides the intensity of chemiluminescence proves to be proportional to hemoglobin concentration, which when added to the blood plasma entered the fractions with the molecular mass about 250 kD. It is suggested that hemoglobin producing luminescence in the blood plasma is related to haptoglobin.

Blood↗