[The nitroblue tetrazolium reduction test in evaluating the function of the circulating leukocytes in mice with experimental malaria]. / Test vosstanovleniia nitrosinego tetrazoliia v otsenke funktsional'nogo sostoianiia tsirkuliruiushchikh leikotsitov myshei pri éksperimental'noi maliarii.

NBT-test for circulating neutrophils and monocytes in the blood of mice inoculated with Plasmodium berghei, strain N or LNK-65, have been performed. Within the first 24 h of the infection, before the onset of the recordable parasitemia or in the course of the subsequent six days (depending of the strain used for inoculation) a 50-100% reduction in NBT-positive cells was observed. This demonstrates the ability of malaria parasite to suppress the oxygen-dependent enzyme system in circulating phagocytes, neutrophils and monocytes of the host blood. The results of NBT-test could be utilized for the investigation of immunological disorders and also for the differential diagnosis of malarial infection.

Human red cells scavenge extracellular hydrogen peroxide and inhibit formation of hypochlorous acid and hydroxyl radical.

The ability of intact human red cells to scavenge extracellularly generated H2O2 and O2-, and to prevent formation of hydroxyl radicals and hypochlorous acid has been examined. Red cells inhibited oxidation of ferrocytochrome c by H2O2. Cells treated with aminotriazole no longer inhibited, indicating that protection was almost entirely due to intracellular catalase. Contribution by the GSH system was slight, and apparent only with low H2O2 concentrations when catalase was inhibited by aminotriazole. The cells were about a quarter as efficient at inhibiting cytochrome c oxidation as an equivalent concentration of purified catalase. No inhibition of O2(-)-dependent reduction of ferricytochrome c or nitroblue tetrazolium was observed, although extracted red cell superoxide dismutase inhibited nitroblue tetrazolium reduction at one fortieth the concentration of that in the cells. Red cells efficiently inhibited deoxyribose oxidation by hydroxyl radicals generated from H2O2, O2- and Fe(EDTA), and myeloperoxidase-dependent oxidation of methionine to methionine sulfoxide by stimulated neutrophils. Most of the red cell inhibition of hydroxyl radical production, and all the inhibition of methionine oxidation, was prevented by blocking intracellular catalase with aminotriazole. Thus red cells are able to efficiently scavenge H2O2, but not O2-, produced in their environment, and to inhibit formation of hydroxyl radicals and hypochlorous acid. They may therefore have an important role in extracellular antioxidant defense.

Evidence of polymorphonuclear neutrophils (PMN) activation in patients with insulin-dependent diabetes mellitus.

Polymorphonuclear neutrophils' chemotaxis, surface charge, superoxide anions generation, NBT (nitro blue tetrazolium) reduction and intracellular lysozyme, and beta-glucuronidase content were estimated in patients with type I diabetes mellitus in a similar state of metabolic control. The chemotaxis of diabetic cells toward bacterial chemotactic factors was similar to controls, whereas migration toward complement-derived chemoattractants was significantly reduced. Polymorphonuclear neutrophils isolated from diabetic patients, when unstimulated, produced significantly greater amounts of superoxide anions and reduced NBT more efficiently. They also revealed reduced surface charge and lower intracellular content of lysozyme, whereas beta-glucuronidase content was similar to controls. The results obtained seem to indicate that neutrophils in patients with insulin-dependent diabetes manifest signs of being in the activated state. The possible mechanisms of such stimulation are discussed.

Phagocytic activity of peripheral blood leukocytes in bulls experimentally infected with IBR/IPV virus (bovid herpesvirus 1).

Functional status of peripheral blood leukocytes was evaluated in bulls infected experimentally with BHV 1. Results of the studies indicated extensive changes in mechanisms of phagocytosis which play significant role restricting spread of viral infection, particularly at the preliminary stage of the infection. Increase in serum antibody titer appeared as a result of a prolonged contact of BHV 1 with cells of the immune system of the organism. The studies, documenting changes in reactivity of peripheral blood phagocytic cells in BHV 1 - infected bulls, point to new possibilities of evaluating immune status in the cattle infected with the virus.

Haemophilus somnus-induced interference with bovine neutrophil functions.

The effect of Haemophilus somnus on bovine polymorphonuclear leukocyte (PMN) function was examined in vitro with whole cells and fractions extracted from the surface of this bacterium. The ability of PMNs to iodinate protein and ingest Staphylococcus aureus was significantly inhibited in the presence of live cells, heat-killed whole cells or supernatant fluid from heat-killed cells, but not in the presence of washed, heat-killed cells. None of the fractions inhibited nitroblue tetrazolium (NBT) reduction by PMNs. The PMN inhibitory factors were further characterized. The material that inhibited S. aureus ingestion was found to be a heat-stable cell surface material of greater than 300 000 MW. The fraction inhibiting iodination of protein was found to be less than 10 000 MW.

[The effect of the cell separation procedure on neutrophilic granulocyte function. II. Research on the bactericidal capacity and the NBT reduction ability of isolated granulocytes]. / Der Einfluss von Zelltrennverfahren auf die Funktion der neutrophilen Granulozyten. II. Untersuchungen zur Bakterizidiekapazität und zum NBT-Reduktionsvermögen von isolierten Granulozyten.

The investigations were aimed at examining the impact of methodically simple separating and enriching techniques for gaining granulocytes on the bactericidal capacity and NBT reduction in isolated granulocytes. For this purpose, granulocytes were gained by the technique of sedimentation and flotation. Granulocytes isolated by the cell separator Haemonetics model 30 were used as reference material. The findings of the investigations together with those of previous studies revealed no indication of the granulocyte function and morphology being damaged by the separating techniques used.

[Effect of interferon on the increased reduction of nitroblue tetrazolium (NBT)]. / Effet de l'interféron sur l'augmentation de la réduction du nitrobleu de tétrazolium (NBT).

Human leukocyte interferon (HL-IF) enhanced the NBT reduction of human peripheral neutrophil in vitro. Dose relation between IF activity and the NBT reduction was recognized. Heat-inactivated HL-IF, HL-IF neutralized by anti-IF serum or heterologous IF could not increase the NBT reduction.

Superoxide-independent platelet response to xanthine oxidase.

Xanthine oxidase (1--5 microgram/ml) from cow's milk induces shape change, aggregation, and the release reaction of human washed platelets. Xanthine oxidase plus xanthine produce superoxide radicals, which reduce nitro blue tetrazolium. Superoxide dismutase, allopurinol, or ommission of xanthine inhibits the reduction of nitro blue tetrazolium but has no influence on the platelet response to xanthine oxidase. In contrast, small amounts of plasma or apyrase from potatoes abolish the effect on platelets, but not the enzyme activity of xanthine oxidase. Comparison of two xanthine oxidase preparations shows that higher specific enzyme activity corresponds to a lesser effect on platelets. The results suggest that platelet and enzyme activities reside in different components of xanthine oxidase preparations.

[Capacity of nitroblue tetrazolium-reduction of neutrophilic granulocytes (author's transl)]. / Nitroblau-Tetrazolium-Reduktionskapazität von neutrophilen Granulocyten

A modification of the NBT-reaction is described which allows a differentiation of the NBT uptake and NBT-reduction. By means of this method it has been shown that the capacity of NBT-reduction of neutrophil granulocytes taken from hematologically healthy persons is independent of the probands' age and, moreover, of the presence of acute infections and their etiology. It has been shown, that the increase in the NBT-reduction of neutrophilic granulocytes of newborns and persons with acute bacterial infections results from an increased NBT-ingestion. To grive an example of a strongly reduced capacity of NBT-reduction of the neutrophilic granulocytes 2 patients suffering from fatal granulomatous disease in childhood have been examined.

Direct spectrophotometric observation of intracellular nitro-blue tetrazolium and its formazan by multiple internal reflectance infrared spectroscopy.

A technique is described which permits the direct, infrared (IR) spectrophotometric observation of peripheral leukocytes by utilizing multiple internal reflectance (MIR) spectroscopy on zinc selenide prisms. The IR spectra of nitro-blue tetrazolium (NBT) and its derivative, nitro-blue diformazan (NBF), are described and examined and these spectra are compared with those of the intracellular NBT and NBF yielding several peaks which may prove to be analytically useful. Additionally, the presence of unreduced NBT in leukocytes is demonstrated, which microscopic and chemical "NBT tests" have not previously done.