Reaction phagocytic

Omara FO, Flipo D, Brochu C, et al. 1998. Lack of suppressive effects of mixtures containing low levels of methylmercury (MeHg), polychlorinated dibenzo-p-dioxins (PCDDS), polychlorinated dibenzofurans (PCDFS),and aroclor biphenyls (PCBS) on mixed lymphocyte reaction, phagocytic, and natural killer cell activities of rat leukocytes in vitro. J Toxicol Environ Health A54 561-577. 

Dead or live bacteria may be effective to stimulate inflammatory reactions of phagocytic cells against tumor cells. The best-characterized treatment is the use of Bacillus Calmette Guerin (BCG) in the case of bladder cancer where activation of the immune response is capable of controlling tumor growth. 

Particulate Reactions 2.1.2 Phagocyte-derived Free 248 2.5.2 Alzheimer s Disease 3. Antioxidant Defence Mechanisms and 252... 

The dismutation (disproportioning) of two free radicals is accompanied by release of a portion of reaction energy as a light quantum. As the quantum yield of such a process is extremely low, the detection of this type of chemiluminescence is technically complicated. Several compounds like lucigenin and luminol have a high quantum yield after reaction with peroxide radicals. Therefore, they are widely used for the detection of these radicals, particularly in the examination of phagocyting cells. 

At the same time the interaction of superoxide with MPO may affect a total superoxide production by phagocytes. Thus, the superoxide adduct of MPO (Compound III) is probably quantitatively formed in PMA-stimulated human neutrophils [223]. Edwards and Swan [224] proposed that superoxide production regulate the respiratory burst of stimulated human neutrophils. It has also been suggested that the interaction of superoxide with HRP, MPO, and LPO resulted in the formation of Compound III by a two-step reaction [225]. Superoxide is able to react relatively rapidly with peroxidases and their catalytic intermediates. For example, the rate constant for reaction of superoxide with Fe(III)MPO is equal to 1.1-2.1 x 1061 mol 1 s 1 [226], and the rate constants for the reactions of Oi and HOO with HRP Compound I are equal to 1.6 x 106 and 2.2 x 1081 mol-1 s-1, respectively [227]. Thus, peroxidases may change their functions, from acting as prooxidant enzymes and the catalysts of free radical processes, and acquire antioxidant catalase properties as shown for HRP [228] and MPO [229]. In this case catalase activity depends on the two-electron oxidation of hydrogen peroxide by Compound I. 

Rodenas et al. [77] studied PMN-stimulated lipid peroxidation of arachidonic acid. As MDA formation was inhibited both with L-arginine (supposedly due to the formation of excess NO) and DTPA (an iron ion chelator), it was concluded that about 40% of peroxidation was initiated by hydroxyl radicals formed via the Fenton reaction and about 60% was mediated by peroxynitrite. However, it should be noted that the probability of hydroxyl radical-initiated lipid peroxidation is very small (see above). Phagocyte-mediated LDL oxidation is considered below. 

HOC1 is probably not a single active MPO oxidant able to chlorinate LDL. Hazen et al. [166] have shown that such a powerful oxidant as molecular chlorine is formed under in vitro conditions during the reaction of MPO-hydrogen peroxide-chloride system of phagocytes with LDL. They pointed out that there is an equilibrium between HOC1 and Cl2, which is shifted to the right under acidic conditions ... 

Hamilton Umicon Lumicon chemi- and biolumium assay luminometer This equipment is used in test-tube scale luminescent immunoassays. With its sample compartment (thermostatted by means of Peltier elements, which allow the temperature to be set from 15°C to 40°C with a precision of 0.1°K) this instrument is suitable for the measurement of temperature-sensitive bioluminescence resulting from enzymic reactions and also in phagocyte-mediated luminescence measurements. 

The respiratory burst of phagocytes is catalysed by a membrane-bound NADPH oxidase that is responsible for the reaction ... 

Fluorescent particles that have been opsonized with serum or specific IgG are mixed with phagocytic leukocytes at 37°C and continuously mixed to optimize the cell-particle interaction. The reaction is stopped by the addition of ice-cold medium, and the free particles are washed away from the leukocytes by centrifugation. The cells are resuspended in cold medium and analyzed... 

Phagocytic leukocytes that are exposed to opsonized particles, chemoattractants, or selected cytokines undergo a rapid burst in oxygen consumption and activation of the enzyme responsible for the oxidative metabolic burst, NADPH oxidase (reviewed in ref. 1). Active NADPH oxidase catalyzes the reaction ... 

Unlike IgG, IgA does not cross the placenta, but like IgG, both the 10 S and the 11 S dimers of IgA are known to fix complement and seem to have the ability to block IgE reaction. This property, as well as its phagocytic role, adds to its efficient antibody role in the mucosal surfaces of the body. Normal serum concentration in tropical populations are similar to, or slightly higher than, those of persons living in the temperate regions. However, it should be noted that normal Caucasians do not attain adult levels of IgA until the fifteenth year whereas in some tropical children the adult level of IgA may be reached by the tenth year of age (W7) (see Fig. 2). 

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