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Query: KEGG:D02003 (NBT)
 1,323 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Optimal conditions for the NBT-reduction test have been sought. Increasing heparin concentrations up to 100 units per ml and a delay in performance of the test, especially when blood specimens are kept at room temperature, resulted in higher values for the NBT index, which then sometimes exceeded the upper limit of normal in healthy people and in uninfected patients. The effect of pH, composition of the buffer, and dye concentration was also investigated. Phosphate-buffered saline pH 7-2 containing 0-1% NBT dye, without glucose, gave the most reliable results. In endotoxin-stimulated NBT tests, the following procedure is recommended: incubation of 0-1 ml whole blood with lyophilised endotoxin 20 mug per ml. for 15 min. in a 37 degree C water bath, followed by the standard test with a 0-2% NBT solution. By this technique, the leucocyte reaction to various types of lipopolysaccharides was of the same order of magnitude. Drug therapy having an effect on blood components lowered this reaction, whatever the source of endotoxin used as stimulant. The importance of NBT-reduction tests is discussed. Standard conditions of test performance are strictly requisite if comparable results are to be obtained and if data not corresponding with the apparent clinical and other laboratory findings are to be evaluated correctly. The stimulated NBT test, performed in parallel with the standard test, is useful in the interpretation of abnormal results and in the detection of factors with a temporary or permanent effect on the phagocytic activity of pmn leucocytes.
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PMID:Standardisation of the nitroblue-tetrazolium test. 23 38

A new luminescent marker for the immunochemical detection of proteins and nucleic acids on filters is reported. The label consists of inorganic crystals, generally called phosphors, with a particle size of 0.1-0.3 microns, stabilized in suspension with polycarboxylic acids and subsequently conjugated to immunoreactive macromolecules. Immunophosphor conjugates exhibit slowly decaying fluorescence that is strong and practically nonfading and not sensitive to quenching by water molecules. They are therefore suited for conventional fluorescence detection as well as for time-resolved detection. The lifetime of the phosphors was in the micro/milliseconds range upon excitation with ultraviolet light. Proteins or nucleic acids immobilized on nitrocellulose filters were detected immunochemically or by hybridization, using haptenized nucleic acid probes followed by immunochemical detection, respectively. The ultimate detection limit of proteins, using phosphor-labeled macromolecules including an immunochemical amplification step, was found to be 10 fg. The detection limit of nucleic acids was 300 fg for demonstration of hapten-labeled probes and 10 pg in hybridization formats with hapten-labeled probes. The sensitivity of methods using phosphor-labeled macromolecules was in all cases as good as or better than that of methods using alkaline phosphatase developed to NBT/BCIP. The use of immunophosphors for detection of proteins and nucleic acids on Western and Southern blots is demonstrated. Finally, the use of multiple phosphors with different kinetic and spectral characteristics for multiparameter studies is indicated.
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PMID:Immunochemical detection of proteins and nucleic acids on filters using small luminescent inorganic crystals as markers. 141 29

N-phenylacetyl dehydroalanines are captodative olefins. They inhibit two processes mediated by superoxide anion (O2-.) in a concentration dependent manner: reduction of NBT to blue formazan and oxidation of epinephrine to adrenochrome. They also inhibit in a dose related way the degradation of deoxyribose produced during either the Fenton reaction or the radiolysis of water, which are the two experimental sources of hydroxyl radical (HO.) production. Based on the results obtained with superoxide dismutase, mannitol, thiourea, and uric acid, we postulate that these competitive inhibitory effects suggest a reaction between the dehydroalanine derivatives and the two oxygen derived radicals. Hydroxyl free radical is scavenged more efficiently than superoxide anion. Substitution of the phenyl ring by methoxy groups does not modify significantly the activity. These molecules possess three target active sites which can react with free radicals.
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PMID:Inhibition of O2-.- and HO.- mediated processes by a new class of free radical scavengers: the N-acyl dehydroalanines. 285 17

The effect of water-bath hyperthermia on rabbit peritoneal macrophages was studied in vitro. The cells were exposed to hyperthermia for 30 min to 4 hours and membrane transport of ions as measured by total and ouabain-inhibited 86Rb influx as well as membrane permeability for 86Rb and 51Cr-labelled intracellular proteins were investigated. Heat-treated macrophages were tested for their ability to phagocyte staphylococci and for reduction of nitroblue-tetrazolium. Moreover the effect of microwave whole-body hyperthermia on rabbit phogocytic cells was studied in vivo. Ion transport to macrophages was stimulated by both intensive (43 degrees C) and moderate (40 degrees C) hyperthermia. On the other hand exposition of the cells to 43 degrees C led to pronounced release of 86Rb and 51Cr from prelabelled cells. NBT reduction was generally decreased in macrophages exposed to 43 degrees C and increased in macrophages kept at 40 degrees C. Clearance of 32P-labelled staphylococci from peripheral blood of microwave-irradiated rabbits diminished when animals were exposed to microwave hyperthermia for f or 7 days (2 hours daily).
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PMID:Effect of hyperthermia on rabbit macrophages. 644 64

The reduction of NBT to formazan has been suggested as an indicator of the reduction potential of biological systems. An increase in the amount of reduced formazan reflects the activation of the hexose monophosphate shunt of phagocytes cultivated in vitro, as a result of cellular stimulation by chemical or biological factors, or during phagocytosis. This phenomenon has been widely used for the determination of activated phagocytes by different methods. However, the technical limitations of these methods have not been evaluated carefully. In the investigations presented here three solvents for formazan, pyridine, dioxane and dimethyl-formamide, have been tested for their suitability as extraction agents. For each solvent the optimal wavelength for photometric evaluation has been determined and dose relation curves between dissolved formazan and OD have been established. Several factors (time, temperature, pH, contamination with water or acid) affecting the dissolving properties and stability of formazan in different solvents have been investigated. With the solvents tested, dioxane proved to be the most suitable agent for extracting NBF. Thus a methodology for the quantitative evaluation of NBT has been established. This method can be used for the identification of activators as well as of inhibitors of the phagocyte system.
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PMID:Nitroblue-tetrazolium test for the functional evaluation of phagocytic cells: a critical analysis of the methodology. 728 90

Different physicochemical studies were undertaken with polycrystalline samples of the complex [Cu2(carnosine)2(H2O)2].2H2O. The infrared spectrum was discussed in comparison with that of free carnosine and on the basis of the known structural data. Magnetic susceptibility measurements were performed between 4.2 and 300 K, showing an effective magnetic moment of 1.79 BM. Both the electronic (reflectance) and ESR spectra were compatible with the existence of a dx2-y2 ground state. The axial reversed ESR spectrum could be explained on the basis of a very weak interdimeric coupling mechanism. The electrochemical behavior, investigated by cyclic voltammetry, shows that the complex possesses a very high redox stability. The possible SOD-like activity was tested using the NBT/superoxide reduction assay. The results show a negligible SOD activity.
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PMID:Spectroscopic, magnetic, and electrochemical behavior of the copper(II) complex of carnosine. 750 89

Phagocytic activity and NBT reduction by blood granulocytes was evaluated in tench during the summer, when water temperature was high (30 degrees C). In vitro assays were performed at two temperatures, 30 degrees C, the temperature of the natural habitat in summer, and 22 degrees C, a commonly used temperature within the optimum range of warm-water fish. The results indicate that blood granulocytes from tench possess a lower capacity to ingest inert particles at 30 degrees C than at 22 degrees C, particularly during long periods of incubation (60 min). The lower capacity for ingesting inert particles at 30 degrees C is due to a decreased effectiveness of phagocytosis at this temperature, but not to a lower number of granulocytes with phagocytic capacity. The decline in inert particle ingestion capacity does not correspond to a lower production of superoxide anion at 30 degrees C, which is similar at both temperatures during phagocytosis, thus indicating a similar capacity for destruction of the antigen at 30 and 22 degrees C.
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PMID:Effect of high summer temperatures upon granulocyte phagocytic function of the tench (Tinca tinca, L.). 762 67

The antioxidant properties of silibin complexes, the water-soluble form silibin dihemisuccinate (SDH), and the lipid-soluble form, silibin phosphatidylcholine complex known as IdB 1016, were evaluated by studying their abilities to react with the superoxide radical anion (O2-.), and the hydroxyl radical (OH.). In addition, their effect on pulmonary and hepatic microsomal lipid peroxidation had been investigated. Superoxide radicals were generated by the PMS-NADH system and measured by their ability to reduce NBT. IC50 concentrations for the inhibition of the NBT reduction by SDH and IdB 1016 were found to be 25 microM and 316 microM respectively. Both silibin complexes had an inhibitory effect on xanthine oxidase activity. SDH reacted rapidly with OH radicals at approximately diffusion controlled rate and the rate constant was found to be (K = 8.2 x 10(9) M-1 s-1); it appeared to chelate Fe2+ in solution. In hepatic microsomes, when lipid peroxidation was induced by Fe2+, SDH inhibited by 39.5 per cent and IdB 1016 by 19.5 per cent, whereas when lipid peroxidation was induced by CuOOH, IdB 1016 exerted a better protective effect than SDH (29.4 per cent and 19.4 per cent inhibition, respectively). In both microsomal systems lipid peroxidation proceeded through a thiol depletion mechanism which could be restored in the presence of silibin complexes. Low levels of lipid peroxidation in pulmonary microsomes point out the differences between in-vitro lipid peroxidation occurring in microsomes of different tissues. The results support the free radical scavenger and antioxidative properties of silibin when it is complexed with a suitable molecule to increase its bioavailability.
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PMID:Free radical scavenging and antioxidative properties of 'silibin' complexes on microsomal lipid peroxidation. 907 34

Water-soluble chitosan oligomer (WSCO) has been reported to have anticancer activity, immuno-enhancing effect and antimicrobial activity. However, other biological activities are unknown. Herein, we have shown that WSCO is able to inhibit proliferation of human leukemia HL-60 cells and induce these cells to differentiate. Treatment with WSCO for 4 days resulted in a concentration-dependent reduction in HL-60 cell growth as measured by cell counting and MTT assay. This effect was accompanied by a marked increase in the proportion of G(0)/G(1) cells as measured by flow cytometry. WSCO also induced differentiation of the cells as measured by phorbol ester-dependent reduction of NBT, morphological changes as examined by Wright-Giemsa staining and expression of CD11b but not of CD14 as analysed by flow cytometry, indicating differentiation of HL-60 cells toward granulocyte-like cells. A combination of low dose of WSCO with all-trans retinoic acid, a differentiating agent toward granulocyte-like cells, exhibited a synergistic effect on the differentiation. In addition, treatment of HL-60 cells with WSCO for 6 or 8 days resulted in the induction of apoptosis as assayed qualitatively by agarose gel electrophoresis and quantitatively by Annexin V technique using flow cytometry. Collectively, there is a potential for WSCO in the treatment of myeloid leukemia.
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PMID:Induction of granulocytic differentiation in acute promyelocytic leukemia cells (HL-60) by water-soluble chitosan oligomer. 1124 31

Electrospray (ES) deposition has been applied to fabricate protein microarrays for immunochemical assay. Protein antigens were deposited as arrays of dry spots on a surface of aluminized plastic. Deposition was performed from water solutions containing a 10-fold (w/w of dry protein) excess of sucrose. Upon contact with humid air, the spots turn into microdroplets of sucrose/protein solution from which proteins were either adsorbed or covalently linked to clean or modified aluminum surfaces. It was found that covalent binding of antigens via aldehyde groups of oxidized branched dextran followed by reduction of the Schiff bonds gives the highest sensitivity and the lowest background in microarray-based ELISA, as compared to other tested methods of antigen immobilization. The minimum concentration of a primary mouse antibody detected in indirect ELISA with such antigen microarrays was approximately 0.3-1.0 ng/mL for ELF-97 or BCIP/NBT substrates of alkaline phosphatase.
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PMID:Immobilization of proteins in immunochemical microarrays fabricated by electrospray deposition. 1179 78


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