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To examine the role of RNA silencing in plant defenses against viroids, a Dicer-like 2 and 4 (DCL2&4)-double knockdown transgenic tomato plant line, 72E, was created. The expression of endogenous SlDCL2 s and SlDCL4 in line 72E decreased to about a half that of the empty cassette line, EC. When challenged with potato spindle tuber viroid (PSTVd), line 72E showed significantly higher levels of PSTVd accumulation early in the course of the infection and lethal systemic necrosis late in the infection. The size distribution of PSTVd-derived small RNAs was significantly different with the number of RNAs of 21 and 22 nucleotides (nt) in line 72E, at approximately 66.7% and 5% of those in line EC, respectively. Conversely, the numbers of 24 nt species increased by 1100%. Furthermore, expression of the stress-responsive microRNA species miR398 and miR398a-3p increased 770% and 868% in the PSTVd-infected line 72E compared with the PSTVd-infected EC. At the same time, the expression of cytosolic and chloroplast-localized Cu/Zn-superoxide dismutase 1 and 2 ( SOD1 and SOD2 ) and the copper chaperon for SOD ( CCS1 ) mRNAs, potential targets of miR398 or 398a-3p, decreased significantly in the PSTVd-infected line 72E leaves, showing necrosis. In concert with miR398 and 398a-3p, SODs control the detoxification of reactive oxygen species (ROS) generated in cells. Since high levels of ROS production were observed in PSTVd-infected line 72E plants, it is likely that the lack of full dicer-likes (DCL) activity in these plants made them unable to control excessive ROS production after PSTVd infection, as disruption in the ability of miR398 and miR398a-3p to regulate SODs resulted in the development of lethal systemic necrosis.

Aims: To evaluate the influences of the accumulative effect of two consecutive rugby sevens matches (Sevens) on aspects of human neutrophil-related non-specific immunity., Methods: In seven players participating in the Japan Sevens, neutrophil reactive oxygen species (ROS) production capability and phagocytic activity were measured using flow cytometry, and serum opsonic activity (SOA) was assessed by measuring neutrophil ROS using the peak height of lucigenin-dependent chemiluminescence before and after two consecutive matches., Results: ROS showed no change immediately after the first match, and had significantly (P<0.05) increased 4 h later, but showed a decrease after the second match. Phagocytic activity showed no change immediately after the first match, but had significantly (P<0.01) decreased 4 h later, and showed a further decrease after the second match, although it was not significant. SOA significantly (P<0.01) increased after the first match, and still maintained its high 4 h later, but decreased after the second match. ROS production capability, phagocytic activity and SOA significantly (P<0.01) decreased after the second match., Conclusions: When rugby players play two consecutive Sevens matches, the exercise loading is thought to be hard, similar to that experienced during a marathon race and intensive or long training in a training camp, although the expected changes were not seen after the first match. Differences between after the first and the second matches may be due to the "cumulative effect".

The effects of long-term training on the production of reactive oxygen species (ROS) from neutrophils and serum opsonic activity (SOA) remain to date unknown. The aim of this study was to evaluate the effect of 6 months training on ROS production and SOA in judoists. Fifty-six judoists were enrolled this study. White blood cell counts, serum creatine kinase (CK), asparate aminotransferase (ASAT), alanine aminotransferase (ALAT), lactate dehydrogenase (LDH) and ROS production from neutrophils, and serum opsonic activity (SOA) using the lucigenin and luminol probes, were measured before and after daily judo exercise (2 h) in March and September. The subjects started their training from March after no exercise for three months, and continued it for 6 months (until September). In March, myogenic enzymes such as CK, ASAT, LDH and neutrophil counts increased and immunoglobulins, complements and SOA decreased after daily judo exercise. Such significant changes were not seen in September. On the other hand, ROS significantly increased after daily judo exercise in both March and September, with no significant difference in the rates of change. In conclusion, 6 month training minimized the changes in SOA as well as muscle enzymes, neutrophil counts, serum immunoglobulins and complements. This could be categorized as a long-term training effect. However, no such change was seen in ROS.

The pathogenic roles of reactive oxygen species (ROS) have been implicated in ulcerative colitis (UC). The aim of this study was to examine the effects of ecabet sodium on ROS produced by human neutrophils, particularly after being primed by bacterial lipopolysaccharides (LPS). Neutrophils were isolated from six healthy volunteers. Each well of a 96-well microplate received neutrophil suspension (1.0 x 10(5) cells) and the plates were incubated at 37 degrees C for 30 min with or without E. coli LPS (f.c. 0.001 ng/ micro L). Ecabet sodium (f.c. 0-5.0 mg/mL) was added before starting or after finishing the incubation. Neutrophils were stimulated by opsonized zymosan (OZ; 1.0 mg/mL) or calcium ionophore (A21837; 0.3 micro mol/L) and luminol-dependent chemiluminescence response was measured using a Lumi Box H-1000. Ecabet sodium attenuated ROS production at a concentration of 5.0 mg/mL (p < 0.05) in LPS-primed neutrophils. However, attenuating effects were not significantly different when ecabet sodium was added before or after the incubation with E. coli LPS. Ecabet sodium may have some attenuating effects on ROS produced by human neutrophils even after neutrophils are primed by bacterial LPS. These results may explain, in part, the therapeutic effects of ecabet sodium for UC., (Copyright 2003 John Wiley & Sons, Ltd.)

Objective: The aim of this study was to examine the effects of low-level laser therapy (LLLT) on production of reactive oxygen (ROS) species by human neutrophils., Background Data: LLLT is an effective therapeutic modality for inflammatory conditions., Materials and Methods: The laser device used was the infrared diode laser (GaAlAs), 830-nm continuous wave (150 mW/cm(2)). After irradiation, ROS production by neutrophils was measured using luminol-dependent chemiluminescence (LmCL) and expression of CD11b and CD16 on neutrophil surface was measured by flow cytometry., Results: The LmCL response of neutrophils was reduced by laser irradiation at 60 min prior to the stimulation with opsonized zymosan and calcium ionophore. The attenuating effect of LLLT was larger in neutrophils of smokers than non-smokers, while the amount of produced ROS was larger in neutrophils of smokers. Expression of CD11b and CD16 on neutrophil surface was not affected by LLLT., Conclusion: Attenuation of ROS production by neutrophils may play a role in the effects of LLLT in the treatment of inflammatory tissues. There is a possible usage of LLLT to improve wound healing in smokers.

Backgrounds/aims: Chronic gastritis induced by Helicobacter pylori is characterised by considerable neutrophil infiltration into the gastric mucosa without mucosal invasion of bacteria. Bacteria have different characteristics with respect to their ability to stimulate human neutrophils to produce reactive oxygen species and chemokines. The aim of this study was to examine the effects of H pylori water extracts on the oxidative burst and chemokine production of human neutrophils., Methods: Helicobacter pylori cells were extracted by harvesting into distilled water and centrifugation. Neutrophils were incubated with H pylori water extracts and the production of reactive oxygen species was measured using luminol dependent chemiluminescence (LmCL). In addition, the concentrations of chemokines (interleukin 8 (IL-8), macrophage inflammatory protein 1-alpha (MIP1-alpha), and MIP1-beta) were measured by enzyme linked immunosorbent assay. Neutrophils were also stimulated by opsonised zymosan (OZ) after preincubation with H pylori water extracts., Results: Helicobacter pylori water extracts alone induced only a weak oxidative burst but preincubation of neutrophils with water extracts dose dependently enhanced the LmCL response stimulated by OZ. Helicobacter pylori water extracts also stimulated neutrophil IL-8 production, although MIP-1beta production was only stimulated weakly, and MIP-1alpha was not stimulated at all., Conclusions: Helicobacter pylori products in water extracts may have a role in the activation and migration of neutrophils, which results in enhanced oxidative damage to gastric mucosa. These findings may explain the pathology of H pylori induced gastritis, in which there is little invasion of bacteria into the gastric mucosa.

Background: Bacteria have different characteristics in stimulation of human neutrophils to produce reactive oxygen species (ROS) and chemokines. This study examined the ability of Helicobacter pylori to induce production of ROS and chemokines by human neutrophils., Methods: H. pylori strains (1.5 x 108 CFU/ml) were cocultured with 5 x 104 neutrophils isolated from healthy subjects. Samples were incubated with human serum with or without IgG antibodies to H. pylori. ROS production was measured using luminol-dependent chemiluminescence (LmCL), and the concentrations of chemokines (IL-8, RANTES, MIP-1alpha and MCP-1) were measured by ELISA., Results: The mean of the highest LmCL (peak height; PH) value stimulated by H. pylori was 3318 in the absence of serum. PH increased to 4687 when incubated with anti-H. pylori antibody-positive sera (p <.001) but antibody-negative sera did not affect LmCL response. The mean final concentration of IL-8 produced in the absence of serum was 142.6 pg/ml. Increased IL-8 production was seen by addition of antibody positive serum (p <.01). IL-8 production was not significantly correlated with production of ROS. On the other hand, H. pylori stimulation did not induce neutrophil production of RANTES, MIP-1alpha or MCP-1., Conclusions: H. pylori was capable of inducing IL-8 production by human neutrophils, but not C-C chemokines. Production of C-X-C dominant chemokine by neutrophils is consistent with the pathological characteristics of H. pylori-induced gastritis, where persistent neutrophil infiltration is present.

Background: Short-chain fatty acids enema has been shown to be effective in the treatment of ulcerative colitis (UC). However, the mechanisms that lead to this response have not been well characterized. The aims of this study were to investigate the effect sodium butyrate has on reactive oxygen species (ROS) generation by human neutrophils, which are responsible for mucosal injury., Methods: Human neutrophils incubated with or without sodium butyrate were stimulated with opsonized zymosan (OZ) or phorbol myristate acetate (PMA). ROS generation was largely differentiated with flow cytometry assays of hydroethidine oxidation and dichlorofluorescein oxidation for superoxide anion and hydrogen peroxide respectively, and luminol-dependent chemiluminescence for myeloperoxidase-mediated oxidants., Results: Sodium butyrate (up to 50 mM) did not alter hydroethidine oxidation upon stimulation of the OZ or PMA. However, sodium butyrate at a concentration of 25 mM elevated dichlorofluorescein oxidation to 125 + 8% (P = 0.028) of control upon stimulation of OZ and to 191 +/- 30% (P = 0.0016) upon stimulation of PMA. Contrary to these results, sodium butyrate greatly inhibited chemiluminescence responses in a dose-dependent manner. The inhibition by 50 mM sodium butyrate was 61 +/- 6% upon OZ and 71 +/- 9% upon PMA, respectively., Conclusions: These data indicate that sodium butyrate up-regulates hydrogen peroxide generation but down-regulates generation of myeloperoxidase-mediated oxidants, the latter being more potent in killing microorganisms and in inducing tissue injury. A possible mechanism is suggested whereby sodium butyrate may inhibit myeloperoxidase activity and hence attenuate the destructive activities of neutrophils in UC.

The pathogenic role of human neutrophils has been implicated in Helicobacter pylori-associated gastritis. Ecabet sodium, a locally acting antiulcer drug, has anti-H. pylori actions. The aim of this study was to examine the effects of ecabet on the ability of H. pylori to stimulate human neutrophils. H. pylori were added to 1 x 10(5) neutrophils and incubated for 30 min in the presence of ecabet. Bacterial suspensions which had been incubated with ecabet for 30 min were also used to stimulate neutrophils. The intracellular production of reactive oxygen species was measured with a FACScan. Bacterial suspensions were also added to neutrophils in the presence of ecabet and incubated at 37 degrees C for 12 h to measure interleukin (IL)-8 production by enzyme-linked immunosorbent assay. The mean fluorescence intensity was found to be attenuated dose-dependently by ecabet (P < 0.01). Ecabet also inhibited IL-8 production by neutrophils in a dose-dependent manner (P < 0.001). Bacteria with prior incubation with ecabet induced significantly lower IL-8 production than those without this incubation (P < 0.05). Ecabet sodium has preventive effects on the ability of H. pylori to stimulate human neutrophils. It may lead to reduced gastritis activity and decreased oxidative damage of the gastric mucosa in H. pylori-associated gastritis.

In order to examine that the effects of interferon alpha (IFN-alpha) on the production of reactive oxygen species from human neutrophils, we investigated in vitro effects of IFN-alpha on neutrophil chemiluminescence responses. Human neutrophils were incubated with 0-1 x 10(5) IU/mL IFN-alpha for 10-60 min just before stimulation with opsonized zymosan and phorbol 12-myristate 13-acetate. Luminol-dependent (LmCL) and lucigenin-dependent (LgCL) chemiluminescence responses were measured using a Lumi Box H-1000. The LmCL response was inhibited by pre-incubation with high concentrations of IFN-alpha (more than 1 x 10(4) IU/mL). In contrast, LgCL response was increased when neutrophils were pre-incubated with high concentration of IFN-alpha. Effects of pre-incubation of IFN-alpha were similar between CL responses stimulated with OZ and PMA. The increase of LgCL might be due to the inhibitory effect of IFN-alpha on myeloperoxidase degranulation, in view of the decreased LmCL responses., (Copyright 2001 John Wiley & Sons, Ltd.)

We have investigated the effect of free radicals on the electrical gap junctions between horizontal cells in the carp retina. In our previous study, L-buthionine sulfoximine, an inhibitor of glutathione synthesis, caused uncoupling of horizontal cells four days after injection. In the present study, we have used paraquat, a generator of exogenous reactive oxygen species, to investigate whether it was the depletion of glutathione or an increase in the level of reactive oxygen species which resulted in horizontal cell uncoupling after L-buthionine sulfoximine injection. Intracellular recordings were made from L-type horizontal cells at various time-points after intravitreal injection of paraquat. Injection of 25nmol paraquat caused an increase in response amplitude to central spot light stimuli by two days after injection, which continued for a further two to three days and had almost disappeared by seven days after injection. There was also a sharp increase in reactive oxygen species production, peaking at four days and disappearing by seven days after injection, and an accompanying depletion and a restoration of glutathione levels with a similar time-course. Marking cells with Lucifer Yellow clearly illustrated uncoupling of horizontal cells after paraquat injection. If paraquat and L-buthionine sulfoximine were injected simultaneously, the increase in response to central spots was observed as early as one day after injection. This response amplitude was not more enhanced than that observed after L-buthionine sulfoximine injection alone, although a dramatic increase in the level of reactive oxygen species was observed. From these results, we suggest that reactive oxygen species are involved in uncoupling, while recovery from uncoupling is dependent on glutathione. Furthermore, we conclude that a balance between glutathione and reactive oxygen species levels is the most important factor controlling gap junctional intercellular communication of L-type horizontal cells in the carp retina.

Hypochlorous acid, which is one of the reactive oxgen species (ROS) produced from human neutrophils, is converted to cytotoxic NH(2)Cl after reaction with ammonia produced by urease in Helicobacter pylori (HP), increasing gastric mucosal injury and with potential development to gastric cancer. We compared the effects of HP on the production of ROS by human neutrophils between two groups-22 patients with gastric cancer and 16 patients without gastric cancer (control group), in whom HP was isolated from stomach biopsy tissues-using a luminol- and lucigenin-dependent chemiluminescence (LmCL and LgCL, respectively). It was very similar in the mean value or variance of mean maximal chemiluminescence intensities (MCI) and peak time in LmCL and LgCL between the two groups. MCI of LmCL was highly correlated with that of LgCL in both groups. These results indicate that there were no differences in the behaviour of HP on human neutrophil chemiluminescence between two groups. The progression from non-malignant mucosa to cancer may be associated with the time-dependent effects of HP via ROS produced by neutrophils on the gastric mucosa., (Copyright 2000 John Wiley & Sons, Ltd.)

To investigate the effects of zinc on non-specific immune functions, we used the chemiluminescence method to examine the capacity of human neutrophils to produce reactive oxygen species and accompanying serum opsonic activity. When neutrophils were stimulated with both opsonized zymosan and phorbol myristate acetate in the presence of 1-10(-3) mmol/L zinc lucigenin-dependent CL responses were stable or declined, whereas luminol-dependent CL responses were significantly enhanced. The results suggest that zinc activates protein kinase C and promotes MPO degranulation and ROS metabolism, especially in hypochlorous acid production, which have the direct action of causing microbial death. Further, the lucigen-dependent CL response stimulated with OZ was strongly enhanced by anti-MPO antibodies, whereas the enhancement was less in the presence of zinc, suggesting that zinc may suppress the receptor-mediated signal transduction process. Both responses were inhibited at 10 mmol/L. Serum opsonic activity was enhanced by zinc at 10(-4) and 10(-3) mmol/L but reduced at 10 mmol/L. These data indicate that addition of zinc around and above normal physiological concentrations facilitates neutrophil functional activity and serum opsonic activity, whereas these are inhibited by a lack of zinc or an excessive amount, suggesting that zinc is essential for optimal functioning of non-specific immunity., (Copyright 2000 John Wiley & Sons, Ltd.)

Decaglycerol mono-oleate (DGMO), a type of food additive (a polyglycerol ester of fatty acids), was evaluated for its in vitro effect on reactive oxygen species (ROS) generation by human neutrophils using a luminol-dependent chemiluminescence assay. Neutrophils were isolated by the Histopaque-1077/1119 double density gradient technique. Opsonized zymosan (OZ) and phorbol 12-myristate 13-acetate (PMA) were employed as artificial stimuli. DGMO inhibited the chemiluminescence response of OZ-stimulated neutrophils by 58% (p < 0.01) at a concentration of 0.5 mg/mL. DGMO inhibited the PMA-induced chemiluminescence by 40% (p < 0.01) at a concentration of 0.01 mg/mL. The inhibition phenomena could not be attributed to light absorption by DGMO alone, because the percentage chemiluminescence in the presence of DGMO is lower than the percentage transmittance of DGMO at 425 nm. These results suggest that DGMO downregulates ROS generation by human neutrophils., (Copyright 1999 John Wiley & Sons, Ltd.)

This study was done to determine if the production and metabolism of reactive oxygen species from human neutrophils were modulated by the treatment of interferon-alpha (IFN-alpha). Luminol-dependent Chemiluminescence (LmCL) responses were inhibited by a high concentration of IFN-alpha (more than 1 x 10(4) IU/ml) when opsonized zymosan (OZ) and phorbol 12-myristate 13-acetate (PMA) were used as stimulants. However, these responses were increased by 1 x 10(3) IU/ml of IFN-alpha with Ca(2+)-ionophore A23187 stimulation. Lucigenin-dependent Chemiluminescence (LgCL) responses were inhibited by all concentrations. These findings suggest the possibility that IFN-alpha inhibits activation of protein kinase C (PKC), whereas the resulting effect might be due to the inhibition of myeloperoxidese (MPO) degranulation. Preincubation of human neutrophils with IFN-alpha for 30, 60 or 120 minutes and subsequent stimulation with OZ, PMA and Ca(2+)-ionophore A23187 caused an increase LgCL responses, while inhibiting LmCL responses. These findings suggest that preincubation of human neutrophils with a high concentration of IFN-alpha might enhance the NADPH-oxidase activity, although a relative increase of LgCL was due to the inhibition MPO degranulation.

We investigated the effects of acute endurance exercise and habitual physical activity for health maintenance on human neutrophil function in 12 untrained men. The acute exercise condition was a continuous exercise for 90 minutes at the intensity of 50% and 55% of maximal oxygen uptake (VO2max) on an ergometer. The training program was 3 km jogging three times per week for 8 weeks. The capacity of neutrophils to produce reactive oxygen species (ROS) was detected with lucigenin-dependent chemiluminescence (LgCL) and luminol-dependent chemiluminescence (LmCL) on stimulation with opsonized zymosan (OZ) and phorbol myristate acetate (PMA). As for the acute exercise effects, both LgCL and LmCL responses of neutrophils, stimulated using PMA consistently increased after exercise at 50%VO2max, whereas those stimulated with OZ remained unchanged. At 55%VO2max, LgCL responses to both stimulants increase maximally 1 h after exercise, and then decreased 3 h after exercise, whereas LmCL responses to both stimulants increased continuously after exercise at 55%VO2max. These phenomena observed at 55%VO2max compared to 50%VO2max suggests the improved capacity of producing ROS neutrophils after exercise. The number of neutrophils also increased maximally 1 h after exercise, due to the mobilization of band neutrophils (shift to the left), suggesting that functional changes was associated with cell mobilization. The increase in the capacity of neutrophils to produce ROS and marked neutrophilia following the acute endurance exercise suggests that a large quantity of ROS may be produced in vivo. As for the training effects, the LgCL and LmCL responses were maintained in the exercise group as compared to the decreased ones in the control group. The difference between the exercise group and the control group was observed only in LgCL response to OZ. Humoral immune factors (IgG, IgA, IgM, C3, C4) and serum opsonic activity were also unaltered. These phenomena suggest that homeostasis might be kept constant in terms of immunity through regular physical activity.

The chemiluminescence (CL) assay has been used to measure the reactive oxygen species (ROS)-generating capacity of phagocytes. To achieve more optimal measurement conditions for a multi-channel microplate photon-counting CL analyzer with the cooled charge-coupled device (CCD) camera which offers enhanced sensitivity, we investigated factors affecting the variability in lucigenin-dependent CL (LgCL) measurement of human neutrophils stimulated with either opsonized zymosan (OZ) or phorbol myristate acetate (PMA). We obtained sensitive LgCL responses with good reproducibility and rapid data-acquisition using 50 microl neutrophils (3 X 10(6) cells/ml) and 50 microl of 0.5 mM lucigenin per well, in addition to either 100 microl of OZ (5 mg/ml) when zymosan was opsonized with 10-20% serum or 100 microl of PMA solution (1 X 10(-6) M) with automatic regular intervals of mixing and detection during the continuous measurement at 37 degrees C. Furthermore, we studied the contribution of various ROS to LgCL and luminol-dependent CL (LmCL) using modulators of ROS metabolism including superoxide dismutase (SOD), catalase, deferoxamine and sodium azide (NaN3). LgCL was inhibited by SOD but not by the other agents, whereas LmCL was inhibited by NaN3 and deferoxamine. Thus, it was demonstrated that LgCL detects the superoxide anion with high selectivity whereas the LmCL assay measures myeloperoxidase (MPO)-mediated formation of hypochlorous acid. Such microplate-based multiple measurements facilitate the accurate assessment of phagocytic function.

To investigate the cause of disagreement within the large body of literature concerning the effect of exercise on the capacity of circulating neutrophils to produce reactive oxygen species (ROS), 10 male endurance-trained athletes underwent maximal exercise. The generation of superoxide radical (O2-.) by neutrophils was first detected on a cell-by-cell basis by using histochemical nitro blue tetrazolium tests performed directly on fresh unseparated blood, which showed that responsive neutrophils under several stimulatory conditions relatively decreased after exercise. Similarly, O2-. detected with bis-N-methylacridinium nitrate (lucigenin)-dependent chemiluminescence (CL) of a fixed number of purified neutrophils on stimulation with opsonized zymosan was decreased slightly after exercise. In contrast, the 5-amino-2,3-dihydro-1,4-phthalazinedione (luminol)-dependent CL response of the neutrophils indicative of the myeloperoxidase (MPO)-mediated formation of highly reactive oxidants was significantly enhanced after exercise. It therefore suggests that the pathway of neutrophil ROS metabolism might be forwarded from the precursor O2-. production to the stages of more reactive oxidant formation due to the facilitation of MPO degranulation. In addition, these phenomena were closely associated with the exercise-induced mobilization of neutrophils from the marginated pool into the circulation, which was mediated by the overshooting of catecholamines during exercise. These findings indicate that the use of different techniques for detecting ROS or the different stages of neutrophil ROS metabolism could explain some of the disparate findings of the previous studies.

Recently, the numbers of city marathon runners and joggers have increased. They believe that exercise can enhance their fitness level and health maintenance. However, many researchers have suggested that exhausting exercise may increase the risk of infection and free radical generation. In this study, eight male and ten female city marathon runners who participated in the Akita Nairiku Resort Cup 100-km Challenge Marathon Race were studied using luminol-dependent chemiluminescence (LDCL) to examine the ability of their neutrophils to produce reactive oxygen species. Furthermore, serum opsonic activity using LDCL, serum concentrations of the third and fourth components of the complement (C3, C4), the total number of leukocytes, and proportion of leukocytes were also determined. Evaluation of LDCL was undertaken using the maximum light emission (peak height) and the time to reach the maximum light emission (peak time) in the response curve of LDCL. Following the race, the peak time was prolonged by 11% in males and 15% in females, and the peak height increased by 68% in males and 48% in females. These results suggest that exhausting exercise stimulates neutrophils to produce reactive oxygen species. The total number of leukocytes increased about twofold, whereas the number of neutrophils increased about threefold after the race as compared to before. The rate of the increase in leukocytes was closely associated with that of neutrophils (r = 0.96, P < 0.01). Therefore, the leukocytosis observed in this study was dependent on neutrophilia. Serum opsonic activity and serum concentrations of C3 and C4 were not changed following the race. The increase in the ability of neutrophils to produce reactive oxygen species and neutrophilia after the race, suggests that a large quantity of reactive oxygen species may be produced in vivo following exhausting exercise.

Many metal materials are used in clinical medicine and the number used is increasing. However, there are a few papers concerning the biological effects, especially effects of clinically used metals on cellular immunity. In this paper, silver (Ag), nickel (Ni), cobalt (Co), and chromium (Cr), clinically commonly used metals, the effects of which on neutrophilic activity have already reported using the luminol-dependent chemiluminescence (LDCL) method, were examined to determine their influence on the reactive oxygen species (ROS) generating capacity of human neutrophils and on a serum opsonic activity. Silver suppressed the ROS generating capacity of neutrophils in a dose-dependent manner but did not affect the serum opsonic activity. Nickel also suppressed the ROS generating capacity of neutrophils but, at some concentrations, caused the serum opsonic activity to increase. In contrast, Cobalt increased both the ROS generating capacity of neutrophils and the serum opsonic activity. Like silver, chromium did not affect the serum opsonic activity and suppressed the ROS generating capacity of neutrophils. However, the suppression of ROS generating by chromium occurred differently from that of silver. In the cases of nickel and cobalt, effects of these metals on hemolyzing activity of serum complements (CH-50) were measured and consumption of complements was observed at the same metal concentration at which serum opsonic activity was elevated. In this paper, we report that some metals influence not only the ROS generating capacity of neutrophils but also the serum opsonic activity, results thought to be important for more details studies of the effects of metals on cellular immunity.