Significance of soil moisture on temperature dependence of Hg emission.

Soil moisture is a key factor for mercury (Hg) emission from soil. Despite its significance for Hg emissions, the effect of soil moisture on Hg flux and fractions has not been thoroughly investigated. The objective of this study was to elucidate the influences of soil moisture and temperature on Hg fluxes from soils and Hg fractions. A kinetic study was performed to measure Hg emission fluxes of six soil samples under different temperature (T) (15 °C, 20 °C, 25 °C, 30 °C, and 35 °C) and moisture conditions (0%, 10%, and 20% added water). The results showed that the Hg fluxes increased with increases in T and soil moisture. A linear correlation was found between ln (Hg emission flux) and 1/T for the six soil samples at different moisture contents (R2 = 0.73-0.99). The range of activation energy (Ea) values was 25.31-57.86 kJ/mol. The Hg fractions in soils of different moisture content were determined by a sequential extraction method. The results demonstrated that soil moisture affected the Hg fractions in soils. The Ea values had different relationships with soil moisture in different soils. There were correlations between Ea and the elemental and mercuric sulfide fractions for air-dried soils. However, for moist soils, Ea was negatively correlated with the water-soluble and acid-soluble fractions. Collectively, the combination of the Hg emission kinetics and Hg fraction measurement of different moist soils indicated that Hg emission was affected by both total Hg concentration and Hg fractions.

Efficacy and Safety of Salmeterol/fluticasone Combination Therapy in Infants and Preschool Children with Asthma Insufficiently Controlled by Inhaled Corticosteroids.

BACKGROUND: Clinical evidences of inhaled salmeterol/fluticasone propionate combination (SFC) therapy are insufficient in early childhood asthma. OBJECTIVES: To examine the effects of SFC50, a combination product of salmeterol xinafoate (50 µg/day) and fluticasone propionate (100 µg/day), in infants and preschool children with asthma. METHODS: The study was conducted at 31 sites in Japan. 35 patients (6 months to 5 years old) with asthma insufficiently controlled by inhaled corticosteroids (100 µg/day) were initiated to treat with SFC50 twice a day for 12 weeks with pressurized metered dose inhalers. The efficacy of SFC50 was assessed using nighttime sleep disorder score as the primary endpoint and the other efficacy measurements. The safety measurement included the incidences of adverse event (AE). RESULTS: Mean patient age was 3.1 years, and 94.2% had mild-to-moderate persistent asthma (atopic type: 65.7%). Nighttime sleep disorder scores, assessed by a nighttime sleep diary, significantly decreased after treatment with SFC50 throughout the study period (p<0.01). SFC50 also significantly improved other efficacy outcomes including asthma symptom score, frequency of short-acting beta-agonist treatment, frequency of unscheduled visits to clinic, frequency of exacerbation due to virus infection, asthma control score and patient QOL score (p<0.01). AEs of cold, upper respiratory inflammation and asthmatic attack occurred in each of the 3 patients (8.6%); however, these were not regarded as treatment-related AEs. CONCLUSIONS: SFC50 improved nighttime sleep disorder score and other efficacy outcome measures with no safety concerns. The results suggest that SFC50 treatment is useful to control the mild-to-moderate asthma in infant and preschool-aged children.

Effects of N loading rate on CH4 and N2O emissions during cultivation and fallow periods from forage rice fields fertilized with liquid cattle waste.

The use of liquid cattle waste (LCW) as a fertilizer for forage rice is important for material recycling because it can promote biomass production, and reduce the use of chemical fertilizer. Meanwhile, increase in emission of greenhouse gases (GHGs), especially CH4 and N2O would be concerned. We conducted a field study to determine the optimum loading rate of LCW as N to promote forage rice growth with lower GHG emissions. The LCW was applied to forage rice fields, N100, N250, N500, and N750, at four different N loading rates of 107, 258, 522, and 786 kg N ha(-1), respectively, including 50 kg N ha(-1) of basal chemical fertilizer. The above-ground biomass yields increased 14.6-18.5 t ha(-1) with increases in N loading rates. During the cultivation period, both the CH4 and N2O fluxes increased with increases in LCW loading rates. In the treatments of N100, N250, N500, and N750, the cumulative CH4 emissions during the entire period, including cultivation and fallow period were 29.6, 18.1, 54.4, and 67.5 kg C ha(-1), respectively, whereas those of N2O were -0.15, -0.02, 1.49, and 5.82 kg N ha(-1), respectively. Considering the greenhouse gas emissions and above-ground biomass, the yield-scaled CO2-equivalents (CO2-eqs) were 66.3, 35.9, 161, and 272 kg CO2 t(-1) for N100, N250, N500, and N750, respectively. These results suggest that N250 is the most appropriate LCW loading rate for promoting forage rice production with lower GHG emissions.

Shifts between Nitrospira- and Nitrobacter-like nitrite oxidizers underlie the response of soil potential nitrite oxidation to changes in tillage practices.

Despite their role in soil functioning, the ecology of nitrite-oxidizing bacteria, NOB, and their response to disturbances such as those generated by agricultural practices are scarcely known. Over the course of 17 months, we surveyed the potential nitrite oxidation, PNO, the abundance of the Nitrobacter- and Nitrospira-like NOB (by quantitative PCR) and the community structure of the Nitrobacter-like NOB (by PCR-DGGE and cloning-sequencing targeting the nxrA gene) in soils for four treatments: after establishment of tillage on a previously no-tillage system, after cessation of tillage on a previously tillage system, and on control tillage and no-tillage systems. Key soil variables (moisture, organic carbon content and gross mineralization--i.e. ammonification--measured by the 15N dilution technique) were also surveyed. PNO was always higher for the no-tillage than tillage treatments. Establishment of tillage led to a strong and rapid decrease in PNO whereas cessation of tillage did not change PNO even after 17 months. PNO was strongly and positively correlated to the abundance of Nitrobacter-like NOB and was also strongly related to gross mineralization, a proxy of N-availability; in contrast, PNO was weakly and negatively correlated to the abundance of Nitrospira-like NOB. Selection of a dominant population was observed under no-tillage, and PNO was loosely correlated to the community structure of Nitrobacter-like NOB. Our results demonstrate that Nitrobacter-like NOB are the key functional players within the NOB community in soils with high N availability and high activity level, and that changes in PNO are due to shifts between Nitrospira-like and Nitrobacter-like NOB and to a weaker extent by shifts of populations within Nitrobacter-like NOB.

Prevention of lead leaching from fly ashes by mechanochemical treatment.

Fly ashes from a municipal solid waste incinerator were subjected to mechanochemical (MC) treatment in a planetary ball mill, and the treated fly ashes were cemented with a binder. The leachability of lead (Pb) from the treated fly ashes and from the cement product were investigated, and the speciation of lead in the treated and untreated ashes was determined by X-ray absorption fine structure (XAFS) analysis. MC treatment of the fly ashes and subsequent cementation prevented Pb leaching by 99.9%, whereas MC treatment alone prevented Pb leaching by 92.8%. Analysis of the X-ray absorption near-edge spectrum of the untreated fly ashes revealed that the predominant Pb species in the ashes was PbCl(2). In contrast, the counterpart in the treated fly ashes was Pb(3)O(4) insoluble in water. The formation of a species of Pb with a lower solubility in water than that of PbCl(2) was confirmed by MC treatment of PbCl(2)-spiked fly ashes for 48h, indicating the reduction of PbCl(2) in the spiked fly ashes to Pb via Pb(3)O(4) during MC treatment. Our results indicate that such reduction to an insoluble species prevented Pb from leaching and that MC treatment followed by cementation is a feasible method for the recycling of fly ashes.

Expression of activated signal transducer and activator of transcription-3 predicts poor prognosis in cervical squamous-cell carcinoma.

BACKGROUND: Stat3 is a member of the Janus-activated kinase/STAT signalling pathway. It normally resides in the cytoplasm and can be activated through phosphorylation. Activated Stat3 (p-Stat3) translocates to the nucleus to activate the transcription of several molecules involved in cell survival and proliferation. The constitutive activation of Stat3 has been shown in various types of malignancies, and its expression has been reported to indicate a poor prognosis. However, the correlation between the constitutive activation of Stat3 and the prognosis of cervical cancer patients has not been reported. METHODS: The immunohistochemical analysis of p-Stat3 expression was performed on tissues from 125 cervical squamous-cell carcinoma patients who underwent extended hysterectomy and pelvic lymphadenectomy, and the association of p-Stat3 expression with several clinicopathological factors and survival was investigated. RESULTS: Positive p-Stat3 expression was observed in 71 of 125 (56.8%) cases and was significantly correlated with lymph node metastasis, lymph vascular space invasion, and large tumour diameter (>4 cm) by Fisher's exact test. Kaplan-Meier survival analysis showed that p-Stat3 expression was statistically indicative of a poor prognosis for overall survival (P=0.006) and disease-free survival (P=0.010) by log-rank test. CONCLUSION: These data showed that p-Stat3 expression in cervical cancer acts as a predictor of poor prognosis.

Experimental and simulation analysis of community structure of nitrifying bacteria in a membrane-aerated biofilm.

Until now, only few attempts have been made to assess biofilm models simulating microenvironments in a biofilm. As a first step, we compare the microenvironment observed in a membrane aerated biofilm (MAB) to that derived from a two-dimensional computational model with individual ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) embedded in a continuum EPS matrix. Gradients of oxygen were determined by means of microelectrodes. The change in nitrifying bacterial populations with the biofilm depth was quantified using fluorescence in situ hybridization (FISH) in combination with a confocal laser scanning microscopy (CLSM). Microelectrode measurements revealed that oxic and anoxic or anaerobic regions exist within the MAB. The oxygen profile predicted by the model showed good agreement with that obtained by microelectrode measurements. The oxic part of the biofilm was dominated by NSO190 probe-hybridized AOB, which formed relatively large clusters of cells directly on the membrane surface, and by the NOB belonging to genus Nitrobacter sp. On the other hand, NOB belonging to genus Nitrospira sp. were abundant at the oxic-anoxic interface. The model prediction regarding AOB and Nitrobacter sp. distribution was consistent with the experimental counterpart. Measurements of AOB cluster size distribution showed that colonies are slightly larger adjacent to the membrane than at the inner part of the biofilm. The sizes predicted by the current model are larger than those obtained in the experiment, leading to the arguments that some factors not contained in the model would affect the cluster size.

Enhancement of biofilm formation onto surface-modified hollow-fiber membranes and its application to a membrane-aerated biofilm reactor.

Surface-modified hollow-fiber membranes were prepared by radiation-induced grafting of an epoxy-group-containing monomer, glycidylmethacrylate (GMA), onto a polyethylene-based fiber (PE-fiber). The epoxy ring of GMA was opened by introduction of diethylamine (DEA). The bacterial adhesivity to this material (DEA-fiber) was tested by immersion into a nitrifying bacterial suspension. The initial adhesion rates and the amount of attached bacteria of the DEA-fiber were 6-10-fold and 3-fold greater than those of the PE fiber, respectively. A membrane-aerated biofilm reactor (MABR) composed of DEA fibers was developed for partial nitrification with nitrite accumulation. Prior to the nitrification test, it was confirmed that the oxygen supply rate (OSR) was proportional to air pressure up to 100 kPa, allowing easy control of oxygen supply. Stable nitrite accumulation was observed in the partial nitrification test at a fixed oxygen supply throughout the operation period, indicating that oxygen was consumed only by ammonia oxidizers. Furthermore, it was demonstrated that oxygen utilization efficiency (OUE) in the ammonia oxidation process was nearly 100% after 300 h incubation.

Exhaled nitric oxide decreases during exercise-induced bronchoconstriction in children with asthma.

Nitric oxide (NO) produced in the airways can be either detrimental or protective to the host. To investigate the role of NO in the pathogenesis of exercise-induced bronchoconstriction (EIB), we measured exhaled NO (ENO) after exercise challenge in 39 asthmatic and six normal children. FEV(1) and ENO were measured before and at 0, 5, 10, and 15 min after exercise performed on a treadmill for 6 min. EIB was defined as a decrease in FEV(1) of more than 15% after the exercise. Normal children (control group) did not have EIB. Twenty-one patients with asthma had EIB (EIB group) whereas the remaining 18 patients did not (non-EIB group). The baseline ENO value was significantly higher in the asthmatic children than in the normal children, and there was a positive correlation between the maximal percent decrease in FEV(1) and the baseline ENO value (r = 0.501, p = 0.012). At the end of the exercise, ENO had decreased in all the subjects. In the non-EIB and control groups, ENO rebounded to above the baseline at 5 min after the exercise and thereafter. In contrast, ENO remained at a decreased level in the EIB group. The change in ENO did not correlate with the change in minute ventilation, and beta-agonist inhalation at the peak of EIB that accelerated the recovery of FEV(1) did not affect the depressed level of ENO, demonstrating that the reduction of ENO is not a simple consequence of increased ventilation nor airway obstruction. Among the EIB group, steroid-treated patients showed sooner recovery in ENO after the exercise than steroid-naive patients. Our study suggests that NO production in response to exercise may be impaired in patients with EIB, and that ENO represents not only airway inflammation but also a protective function of NO in EIB.

Clinical analysis of multiple primary malignancies of the hypopharynx and esophagus.

PURPOSE: Because the capability to control squamous cell carcinomas of the head and neck has improved recently, the phenomenon of multiple primary malignancies of that region is now recognized with increasing frequency. We reviewed cases of multiple primary squamous cell carcinomas of the hypopharynx and esophagus with regard to their frequency, incidence, and prognosis. PATIENTS AND METHODS: We reviewed 104 cases of hypopharyngeal cancer to determine (1) if and when esophageal cancer occurred, (2) the classification of multiple tumors as metachronous or synchronous, and (3) tumor histology. RESULTS: In most cases of the metachronous type, esophageal cancer followed hypopharyngeal cancer within less than 3 years. Most cases of hypopharyngeal cancer were at an advanced stage, in contrast to esophageal cancer, which were all early stage. These cases had a poor prognosis despite various treatments causing local disease to be well controlled. Endoscopic esophageal mucosal resection was found to be an effective treatment for esophageal cancer, especially in superficial types. CONCLUSIONS: The prognosis and mild systemic damage after endoscopic esophageal mucosal resection compare favorably with surgery, radiation, or systemic chemotherapy.

[Distribution of intraglandular metastatic foci in the contralateral lobe of papillary thyroid carcinoma].

The distribution of metastatic foci in the opposite lobe has not been studied in detail despite of several reports on the high incidence of contralateral metastasis. Whether foci spread to the upper one-third of the contralateral lobe influences the choice of total or subtotal thyroidectomy. Metastasis was studied in 66 patients 11 men and 55 women aged 24-73 years (mean; 51.3), undergoing primary total thyroidectomy from 1988 to 1996. Serial blocks of the opposite lobe, approximately 5 mm thick were sliced and stained by hematoxylin-eosin. Metastases were found in 44 patients (67%). Based on the size of the primary focus, these patients were divided into group A (smaller than one-third of the lobe) and group B (greater than that of group A). The average size of the primary focus was 21 mm in group A and 36 mm in group B. The contralateral metastatic rate was 64% (14/22) in group A and 68% (30/44) in group B. The distribution of metastatic foci in the opposite lobe was studied in 44 positive patients. The spread to the upper one third occurred in 61% (27/44); 29% (4/14) in group A and 76% (23/30) in group B a significant difference (p < .003). We thus concluded that the larger the primary focus, the wider the spread of metastatic foci to the opposite lobe.

Prevention of nephrotoxicity of cisplatin by repeated oral administration of ebselen in rats.

The ability of ebselen, which exhibits glutathione peroxidase (GSH-Px)-like activity, to prevent cisplatin (CDDP)-induced nephrotoxicity was examined in rats. CDDP (6 mg/kg [20 micromol/kg] body weight) was injected intraperitoneally. In subgroups, daily ebselen doses of 2.75 (10 micromol), 5.5 (20 micromol), or 11.0 mg (40 micromol)/kg body weight were administrated orally 1 hour prior to CDDP treatment. Treatment with CDDP alone resulted in significantly increased plasma creatinine (Cr) and blood urea nitrogen (BUN) levels. Repeated administration of 5.5 and 11.0 mg/kg ebselen prevented the CDDP-induced elevation of plasma Cr and BUN levels and protected against kidney damage. Relative to controls, rat that received CDDP treatment displayed a decreased ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG), an indicator directly related to oxidative stress, and elevated malondialdehyde (MDA) levels in the kidney. In comparison with controls, activity of GSH-Px activity, which antioxidant enzyme, was also reduced in the kidney of rats treated with CDDP. Repeated administration of 5.5 or 11.0 mg/kg ebselen prevented CDDP-induced alteration of GSH/GSSG ratios, MDA levels, and GSH-Px activity; however, no protection against CDDP was observed with administration of 2.75 mg/kg ebselen. Effective protection of CDDP-induced nephrotoxicity with ebselen was observed only when the molar amount of each daily ebselen treatment equaled or exceeded

Age affects hibernation in Syrian hamsters (Mesocricetus auratus).

In this study, we aimed to show how age affects hibernation in the Syrian hamster. Experimentally, we used 30 male animals differing in age. The old animals were 20 months of age and the adults were 8 months of age at the end of the test. The young animals were 3 weeks old at the start of testing and 5 months old at the end of the testing period. The torpor observation started October 15, 1996, and ended March 11, 1997, in the laboratory colony maintained under natural photoperiod and outdoor air. Observations were performed around noon daily. Three measures (i.e., prehibernation period [hibernation latency], proportion of hibernation spent in torpor, and proportion of animals in torpor), all of which reflect the strength of occurrence of hibernation, indicated that the older hamsters (1) started hibernation earlier, (2) spent more time in torpor, and (3) had a higher chance of being in torpor than the younger ones during the hibernation season.

Chemokines induce eosinophil degranulation through CCR-3.

BACKGROUND: Such CC chemokines as eotaxin and RANTES induce preferential eosinophil recruitment in allergic inflammation. They also elicit proinflammatory effector functions of eosinophils, such as enhanced adhesion and superoxide generation. Eosinophil degranulation by chemokines, however, has not been studied in detail. OBJECTIVE: The purpose of this study was to identify chemokines and their corresponding receptors that induce eosinophil degranulation by using a panel of chemokines and blocking antibodies to candidate receptors. METHODS: Highly purified eosinophils were preloaded with Fura-2 and stimulated with a panel of chemokine ligands for 14 known chemokine receptors: CCR1 to CCR8, CXCR1 to CXCR4, CX3CR1, and XCR1. Calcium influx was measured with fluorescence spectrometry. Eosinophils were also stimulated with the chemokines in the presence or absence of IL-5, and levels of eosinophil-derived neurotoxin were measured in the supernatant with RIA. Specific antibodies to chemokine receptors were used to block degranulation. RESULTS: Calcium influx was induced by monocyte chemotactic protein (MCP) 1, MCP-3, MCP-4, RANTES, eotaxin, IL-8, and stromal cell-derived factor 1alpha, which are chemokines that bind several chemokine receptors. However, degranulation was induced only by CCR3 ligands, including MCP-3, MCP-4, RANTES, and eotaxin. Priming of eosinophils with IL-5 enhanced CCR3 ligand-induced degranulation but did not cause non-CCR3 ligands to induce eosinophil-derived neurotoxin release. An antibody against CCR3 significantly inhibited degranulation induced by CCR3 ligands, eotaxin, or RANTES. CONCLUSION: These results suggest that chemokine-induced eosinophil degranulation, a major effector of eosinophil functions, is mediated through only CCR3, although some non-CCR3 ligands induce calcium influx in eosinophils. CCR3 may be an important target in the treatment of eosinophilic inflammation.

Chemokine production by the BEAS-2B human bronchial epithelial cells: differential regulation of eotaxin, IL-8, and RANTES by TH2- and TH1-derived cytokines.

BACKGROUND: Bronchial epithelial cells produce many types of chemokines and may contribute to lung inflammation by recruiting inflammatory cells. The CC chemokine eotaxin is a potent, eosinophil-specific chemoattractant that has been detected in the bronchial epithelium of patients with asthma. OBJECTIVES: The aim of this study was to investigate the regulatory mechanisms of chemokine production from bronchial epithelium by inflammatory cytokines, especially T(H)2- and T(H)1-derived cytokines, in bronchial asthma. METHODS: BEAS-2B human bronchial epithelial cells were cultured with TNF-alpha, IL-4, IL-13, and IFN-gamma alone or in combination, after which supernatants were assayed for eotaxin, IL-8, and RANTES proteins with ELISA. Reverse transcription-PCR was also performed. RESULTS: TNF-alpha induced production of eotaxin, IL-8, and RANTES in a concentration-dependent manner. Both IL-4 and IL-13 synergistically enhanced TNF-alpha-induced eotaxin production, whereas IL-8 production induced by TNF-alpha was significantly down-regulated by the T(H)2-derived cytokines. IFN-gamma, a T(H)1 cytokine, counteracted the enhancing effects of IL-4 and IL-13 on eotaxin production. RANTES production by TNF-alpha was not affected by IL-4 and IL-13 but was markedly enhanced by IFN-gamma. CONCLUSIONS: These results suggest that T(H)2 cytokines are involved in preferential recruitment of eosinophils in bronchial asthma by enhancing eotaxin and reducing IL-8 production from bronchial epithelial cells and that T(H)1 cytokines counteract the effects of T(H)2 cytokines by reducing eotaxin production.

[Japanese cedar pollinosis in infants in the allergy clinic].

Recently, the number of patients with Japanese cedar (Cryptomeria japonica) pollinosis has increased, especially in children. However, little is known about the incidence in infants. We studied on the rate of sensitization and the onset of pollinosis in children under 6 years old. The percentage of positive CAP-RAST to Japanese cedar pollen was 27.6%, in 76 infants (51 male and 25 female, 2 months-5 years old) who visited National Mie Hospital pediatric allergy clinic due to bronchial asthma and/or atopic dermatitis. The youngest child who has been sensitized to pollen was 1 year 8 month old boy. The percentage of positive rate of CAP-RAST to house dust mite was 61.8%. Twenty-seven infants (20 male and 7 female, 2-5 years of age) were diagnosed as Japanese cedar pollinosis in National Mie Hospital Otorhinolaryngology clinic in 1999 and 2000. The youngest child with pollinosis was 2 year 5 month old boy. Most of the 27 infants complained of rhinorrhea and/or eye symptoms and some of them complained cough, snoring, or epistaxis. About 40% were sensitized to Japanese cedar and/or cupressaceae pollen alone, 60% were also sensitized to house dust mite. In conclusion, it is possible that the sensitization to Japanese cedar pollen occurs after 2 season of pollen exposure and pollinosis occurs in 2 years old. Japanese cedar pollen has been an important allergen not only in school children, but also in infants.

Mechanisms of eosinophil cationic protein release in the serum: role of adhesion molecules.

BACKGROUND: Measurement of eosinophil cationic protein (ECP) in serum has been utilized as a marker for allergic inflammation. The serum level of ECP represents the level found in vivo plus additional proteins released in vitro from peripheral blood eosinophils during the coagulation period. The mechanisms of release, however, are unclear. We investigated a possible involvement of adhesion molecules in the ECP release. MATERIALS AND METHODS: Venous blood was drawn in the presence of EDTA from allergic donors. The blood was incubated with neutralizing monoclonal antibodies to CD18, CD11a, CD11b, CD29, CD49d, CD54, alpha4beta7, or isotype-matched control antibodies, respectively, at 4 degrees C for 30 min. Calcium gluconate (calcium) was then added to induce coagulation. The blood was further incubated for 90 min and centrifuged to obtain the serum. ECP in the serum was measured with RIA. In some experiments, purified eosinophils were incubated with plasma and calcium, then ECP in the supernatants was assayed. RESULTS: ECP in the samples with calcium was significantly higher than in those without calcium. Purified eosinophils released ECP upon plasma coagulation. Anti-CD18, CD49d, and alpha4beta7 antibodies significantly suppressed ECP levels in the serum. CONCLUSIONS: These results suggest that ECP release in the serum is calcium and plasma coagulation-dependent and that cell adhesion through alphaLbeta2, alphaMbeta2, alpha4beta1 and alpha4beta7 integrins is at least in part responsible for ECP release.

Matrix metalloproteinase-9 in peripheral blood eosinophils.

BACKGROUND: Matrix metalloproteinases (MMPs) are major contributors to tumor invasion, remodeling of connective tissue and infiltration of inflammatory cells and may be important mediators in developing allergic inflammation. Overexpression of MMP-9 mRNA by eosinophils in the asthmatic airways has been reported. To clarify the relative significance of MMP as an inflammatory mediator from eosinophils, we determined the content of MMP-9 in the peripheral blood eosinophils and compared it with the other leukocyte fractions. METHODS: Peripheral blood eosinophils, neutrophils, and mononuclear cells were purified from normal and allergic donors with Percoll gradient centrifugation and CD16 negative selection. Cell lysate and culture supernatants stimulated with IL-5, PAF, and PMA were tested for MMP-9 with gelatin zymography and ELISA. RESULTS: The amount of MMP-9 in highly purified eosinophils, neutrophils, and mononuclear cells was 2.5 +/- 0.9, 4,073 +/- 581, and 7.6 +/- 1.4 ng/5 x 10(6) cells, respectively. There was no difference in MMP-9 content of eosinophils between normal donors and patients with asthma. Culture of peripheral blood eosinophils with IL-5 for 4 days did not induce MMP-9 production. The stimulation of eosinophils with PMA and other secretogogues caused only small amounts of MMP-9 secretion as compared with neutrophils. CONCLUSIONS: These findings suggest that circulating eosinophils normally have only small amounts of MMP-9 and that eosinophils may need complex activation signals to produce significant amounts of MMP as seen in tissues of allergic inflammation.