Acetylsalicylic acid as a modulator of neutrophil peroxidase system.

Effect of acetylsalycilic acid (aspirin; Ron-Pulenk) on activity of mouse neutrophil peroxydase system was investigated. Using luminol-dependent chemiluminscence and cytochemical methods we demonstrated that neutrophil peroxydase system in mice receiving aspirin for 14 days is probably determined by stimulation of myeloperoxydase synthesis.

Clofibrate and dalargin increase luminol-dependent chemiluminescence of mouse blood.

The effects of hypolipidemic drug clofibrate and polypeptide dalargin on activity of the neutrophil peroxidase system in mice were studied using the method of luminol-enhanced chemiluminescence. Clofibrate and dalargin increased the chemiluminescence of mouse whole blood. Their combined use several-fold potentiated this effect.

Effect of some xenobiotics on oxidative metabolism of human blood neutrophils.

The effect of SO3(2-), S(2-), NOs(-), and NH4(+) on activity of the peroxidase-hydrogen peroxide system in human peripheral blood neutrophils was studied by the cytochemical method. We showed that the effect of these xenobiotics on neutrophils is similar to that on plants.

[Toxic effect of heavy metals on human blood neutrophils].

Activity of the peroxidase-hydrogen peroxide system is proposed as a biological marker of ecological risk of heavy metal contamination of the environment. The effect of lead, copper, mercury, and cadmium ions on peroxidase system activity in human peripheral blood neutrophils was studied using cytochemical methods. A possible mechanism of suppression of peroxidase system activity by metal ions is discussed.

[Intracellular transformation of phagosomes].

The transformation of nascent phagosomes into forms capable of interacting with antimicrobial organelles of phagocytes, peroxisomes, depends on certain interactions between phagosomes and other vacuolar organelles. Phagosomes repeatedly interact with early and late endosomes through temporary contacts, which allows them to gain and lose complex sets of proteins. In addition, certain polypeptides are eliminated from phagosomes through recycling.

[Oxides of nitrogen (NO* and NO2-) as cofactors of the myeloperoxidase system].

Myeloperoxidase is the main peroxisomal protein of neutrophils, monocytes, and a subpopulation of tissue macrophages; it plays the key role in protective and inflammatory responses of the organism. This role is mediated by various diffusible radicals formed during oxidative reactions catalyzed by the enzyme heme. Myeloperoxidase and nitric oxide synthase are stored in peroxisomes.

[Gelatinase granules of the neutrophil granulocytes].

The neutrophil contains numerous granules of various composition and structure. For decades, the neutrophil was believed to contain only two granule types, peroxisomes (peroxidase-positive granules) and neutralohydrolasosomes (peroxidase-negative granules). Later existence of the third type distinguished by the presence of gelatinase hydrolyzing collagen and gelatin.

[Myeloperoxidase from neutrophil peroxisomes].

Peroxisomal myeloperoxidase plays a key role in synthesis of oxidants by neutrophilic leukocytes. This heme protein consists of two subunits connected by a disulfide bond. The enzyme uses H2O2 and Cl- for synthesis of HOCl--the major oxidant produced by neutrophils.

[The mechanism of bactericidal activity in phagosomes of neutrophils].

Myeloperoxidase plays the key role in antimicrobial of phagocytes. This enzyme uses hydrogen peroxide and chloride to catalyze hypochlorous acid formation. HOCl is the most probable agent in the oxygen-dependent bactericidal activity in the phagocyte phagosome.

[Antimicrobial activity of myeloperoxidase from neutrophil peroxisome].

Myeloperoxidase plays the key role in antimicrobial oxygen-dependent activity of neutrophils. This heme-containing enzyme catalyzes HOCl formation from H2O2 and Cl-. HOCl is a strong oxidation agent produced at the significant level by neutrophils.

[Composition of neutrophil peroxisomes].

Peroxisomes of neutrophils are formed in promyelocytes. In addition to myeloperoxidase constituting 35% peroxisomes, they contain nonenzymatic antimicrobial cationic peptides and polypeptides, several serine proteases, as well as some other hydrolases and additional components. Similar to serine proteases, these hydrolases can serve as natural antibiotics.

[Chemical basis of nonspecific immunity].

Our knowledge on the nature and quantity of reactive O2 forms generated in phagocytes, particularly, in neutrophil leucocytes, and their role in nonspecific immunity is reviewed. In thermodynamical terms, oxygen is a very reactive molecule and, hence, can react with most chemical elements and many organic molecules. In kinetic terms, O2 is rather inert.

[Chemiluminescence suppression in roots of Pisum sativum L. by various metal ions].

The effect of rare metal ions on the activity of the peroxidase system in Pisum sativum L. roots was studied by luminol-dependent chemiluminescence. Trivalent ions of scandium, gallium, indium, and lanthanum, to different extents, inhibit the chemiluminescence of damaged P.

[Cytochemical evidence for endogenous hydrogen peroxide generation in the neutrophils from human blood smears].

We present more accurate evidence for generation of endogenous hydrogen peroxide as a result of peroxidase-endogenous hydrogen peroxide system activity in the neutrophils (Rogovin et al., 1978). The normal cytochemical reaction of the peroxidase-endogenous hydrogen peroxide system in the neutrophil peroxidasosomes after elimination of water-dissolved H2O2 by KMnO4 indicates the neutrophils on smears as a source of H2O2, rather than alcohol-formaldehyde.

[Antixenosomes].

Data on the existence of organelles, binding and inactivating xenobiotics on the subcellular level in animal and plant cells is presented. The morphology of these organelles both the enzymatic constituents and their expected physiological function in immunological homeostasis are discussed. The data presented suggests that the previously discussed organelles such as chloragosomes, cadmosomes, metallogranules, keratinosomes, lamellar and myeloid bodies of animal and plant cells belong to the united class of organelles--antixenosomes which segregate, bind and inactivate xenobiotics protecting both cells and the entire organism from their harmful effect.

[The antimicrobial proteins and peptides of neutrophilic leukocytes].

Findings suggesting a vast variety of non-enzymic cationic proteins and peptides in human and animal leucocytes are reported. These cationic proteins and peptides demonstrate their antimicrobial and cytotoxic properties due to their detergent characteristics and their capacity to change the permeability of cellular wall and membrane by electrostatic interactions. Information on their homology with some serine proteases is presented.

[The peroxisomes of eosinophilic leukocytes].

Functional properties of peroxidase-containing granules (peroxidasosomes) of eosinophiles are discussed. Findings are reported on the activities of peroxidase systems and of non-enzymic cationic proteins which occur in the eosinophilic peroxidasosomes in normal state and in various pathological states as well as their antimicrobial and antiparasitic activities.

[Increase in the level of luminol-dependent chemoluminescence in mouse blood under the effect of certain synthetic peptides].

Synthetically produced peptides increased the luminol-dependent chemoluminescence of mice whole blood during phagocytosis. Using some peptides it is possible to cause an increase in the antimicrobial peroxidase system activity of neutrophils very rapidly (within seconds).