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1.
The effect of myeloperoxidase, hydrogen peroxide (H2O2) and a halide (Cl) on the opsonizing molecules in immunoglobulin G (IgG) and complement factor C3b was assayed. At concentrations of the enzyme (1 microgram/ml) that can be found in the extracellular fluid during inflammation, the myeloperoxidase-H2O2-Cl system inhibited the opsonizing effect of IgG and C3b measured as phagocytic uptake and superoxide generation. The effect was related to the enzymatic peroxidative activity of the protein. The presence of albumin (10 mg/ml) reduced the effect of myeloperoxidase with 10-20%. Taurine, which in the presence of myeloperoxidase-H2O2-Cl forms hydrophilic chloramines, and D-penicillamine, which scavenges HOCl, neutralize the inhibitory effect of myeloperoxidase. This suggests that either hypochlorous acid or lipophilic chloramines may exert its effect by oxidizing free sulphydryl groups exposed on the opsonizing ligands. Since the myeloperoxidase-H2O2-halide system also affects chemotactic factors, leukotrienes, proteinases and membrane receptors, the system may in several ways affect the development of the inflammatory response. 相似文献
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OBJECTIVE: To determine the vaccination rate among infants discharged from a neonatal intensive care unit (NICU) and factors affecting that rate. DESIGN: Cross-sectional survey conducted when the children were 12 to 18 months of age. SETTING: NICU at the Royal University Hospital, Saskatoon, Sask. PARTICIPANTS: All 395 infants discharged from the NICU between Jan. 1 and June 30, 1992. MAIN OUTCOME MEASURES: Vaccination rate, ethnic background (native or non-native), place of residence (urban or rural), health status (number of days spent in the NICU), reasons for delay in or incomplete vaccinations (those involving parents'' responsibility, infant illness or contraindications). RESULTS: Of the 395 infants, 20 (5.0%) had died and incomplete information was available for 30 (7.6%). Complete data were available for 345 (87.3%). Of the infants for whom data were available, 8 (2.3%) had never been vaccinated and 142 (41.2%) had a delayed vaccination schedule or had not completed their scheduled vaccinations. Only 195 (56.6%) of the infants had received a full vaccination series. Non-native ethnic background was a predictor of completed vaccinations (odds ratio [OR] 5.40, 95% confidence interval [CI] 3.05 to 9.52). In a univariate model, urban area of residence was not a significant predictor of vaccination status, but when ethnic background was controlled for in a multivariate logistic regression analysis, urban area of residence was found to be inversely associated with completed vaccinations (OR 0.34, 95% CI 0.15 to 0.79). The number of days the child had spent in the NICU was not a significant predictor of vaccination status. CONCLUSION: The vaccination rate of infants discharged from the NICU is not optimal. Urban native children appears to be at risk of not being vaccinated. Non-native infants are five times more likely than native infants to have completed all of their scheduled vaccinations. Methods to improve the rate of completed vaccinations, especially for native children, must be sought and tested. 相似文献
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The diminished production of arachidonic acid oxygenation products by elicited mouse peritoneal macrophages: possible mechanisms 总被引:12,自引:0,他引:12
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The stimuli, sn-1, 2-dioctanoylglycerol; (DG8) the calcium specific ionophore, ionomycin, and the chemotactic peptide formylmethionyl-leucyl-phenylalanine (FMLP) can interact with normal human neutrophils and activate their superoxide/hydrogen peroxide generating NADPH-oxidase. In response to the peptide as well as DG8, the neutrophils produced both superoxide (O2-) and hydrogen peroxide (H2O2). Since interaction between the cells and ionomycin was not associated with any notable superoxide production and hydrogen peroxide was induced only in the presence of azide, a potent inhibitor of the hydrogen peroxide-consuming enzymes catalase and myeloperoxidase, we conclude that this stimulus can generate oxygen metabolites intracellularly. Since the DG8-induced production of hydrogen peroxide was increased in the presence of azide, whereas the FMLP-induced response was largely unaffected, we concluded that the three stimuli differ in their capacity to generate oxygen metabolites intracellularly. The use of sn-1,2-didecanoylglycerol (DG10) as stimulating agent did not result in any detectable activation of the NADPH-oxidase. However, preincubation caused an increased (primed) response during stimulation with the chemotactic peptide FMLP. The response of primed neutrophils to FMLP proceeds with a time-course different from that seen in normal cells. From the results presented on FMLP-induced activity in the presence of azide, we conclude that FMLP causes normal cells to produce oxygen radicals which are released from the cells. However, the primed cells are also capable of generating oxygen metabolites that are retained inside the cells. In fact, measurement of the intracellularly generated metabolites discloses this to be the predominant part of the response. 相似文献
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Dahlgren K. V. O. 《Molecular & general genetics : MGG》1918,19(3):220
Ohne Zusammenfassung 相似文献
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Hammock Bruce G. Hartman Rosemary Dahlgren Randy A. Johnston Catherine Kurobe Tomofumi Lehman Peggy W. Lewis Levi S. Van Nieuwenhuyse Erwin Ramrez-Duarte Wilson F. Schultz Andrew A. Teh Swee J. 《Hydrobiologia》2022,849(3):675-695
Hydrobiologia - Condition indices are key predictors of health and fitness in wild fish populations. Variation in body condition, therefore, can be used to identify stressful conditions that may... 相似文献
9.
We review the taxonomic history of pogonophores (frenulates and vestimentiferans), from the species in first described 1914 to the recently described bone-eating worm Osedax. Previous systematists have referred both groups to the rank of phylum, and the animals have been treated as deuterostomes with a dorsal nerve cord. Further knowledge on their embryology, the discovery of the previously overlooked posterior, segmented part provided with chaetae, and access to molecular data, have completely changed earlier views on their affinities. They are now referred to as a single family of polychaete annelids, Siboglinidae. To cite this article: F. Pleijel et al., C. R. Biologies 332 (2009). 相似文献
10.
Human activities have greatly increased the input of biologically available nitrogen (N) from land-based sources to aquatic
ecosystems; yet few studies have examined how human actions influence N export in regions with a strong seasonality in water
availability. In this study, we quantified N inputs and outputs for 23 California watersheds and examined how climate, hydrology,
and land use practices influenced watershed N export. N inputs ranged from 581 to 11,234 kg N km−2 year−1 among watersheds, with 80% of total input for the region originating from agriculture (inorganic fertilizer, manure, and
legumes). Of the potential N sources examined, mean annual concentrations of dissolved organic N and dissolved inorganic N
in study rivers correlated most strongly with manure N input (r
2 = 0.54 and 0.53, respectively). Seasonal N export varied by basin and was correlated with climate, anthropogenic N inputs,
and reservoir releases. Fractional export of watershed N inputs by study rivers annually was small (median of 8%) and scaled
exponentially with runoff (r = 0.66). Collectively, our results show that anthropogenic activities have altered both the magnitude and timing of watershed
N export in California and suggest that targeted management in specific locations and times of the year could reduce N export
to downstream systems in the region. 相似文献