Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eosinophilic bronchitis and desquamation of the bronchial mucosa are the salient features of the pathology of both allergic (extrinsic) and nonallergic (intrinsic) asthma. Because of this association, the possibility of the eosinophil being the cause of the injury to the bronchial mucosa has been investigated during the last decade. In vitro, eosinophil granule major basic protein (MBP) concentrations as low as 10 micrograms.ml-1 cause desquamation and destruction of the epithelium of the airways which mimic the morphology of damage to the mucosa of the bronchi in asthma. Concentrations of MBP in the cytotoxic range for the bronchial mucosa in vitro have been measured in sputum of asthmatics (up to 92 micrograms.ml-1) and decline with treatment. Deposits of MBP have been detected by immunofluorescence within ulcerated areas of bronchial mucosa and necrotic portions of the bronchial wall in patients who had died of asthma. Most recently, the eosinophil peroxidase (EPO) and the eosinophil cationic protein (ECP) have also been found to be toxic for the epithelium of the airways in vitro, thus increasing the cytotoxic capability of the eosinophil against the bronchial mucosa in asthma. These latest research data continue to support the "eosinophil hypothesis" in the pathogenesis of this disease. According to this hypothesis, in the formidably complex network of cells and mediators responsible for the bronchial obstruction, the destruction of the mucociliary apparatus and the characteristic hyperresponsiveness of the airways in asthma; the eosinophil is the principal effector cell. In bronchial asthma a T cell modulated eosinophilic bronchitis is the primary abnormality while bronchospasm and hyperreactivity of the airways are secondary phenomena.
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PMID:The eosinophilic injury to the mucosa of the airways in the pathogenesis of bronchial asthma. 195 9

The monitoring of inflammatory activity in the lungs of patients with chronic obstructive airways disease may be accomplished by the measurement of specific markers of inflammatory cell activity such as the eosinophil cationic protein and the neutrophil-derived myeloperoxidase. However, no specific marker, which reflects the activity of the alveolar macrophage, is available. Eosinophil and neutrophil chemotactic activity may be detected in broncho-alveolar fluid as a sign of macrophage activity. We report preliminary data, which indicate that both chemotactic activities are elevated in patients with chronic bronchitis. The predominant activities elute at a molecular weight of about 10 kDa but also at a position after the total volume of the column. We conclude that secretory products from inflammatory cells may be measured in broncho-alveolar fluid from patients with chronic bronchitis. Whether such measurements will prove useful in relation to therapeutic trials in these patients is not known but is most likely.
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PMID:Indices of inflammatory activity in CB and COAD. Phagocyte secretion and chemotaxis. 223 33

Eosinophil infiltration and degranulation around the tissue-invasive stages of several species of helminths have been observed. Release of eosinophil granule contents upon the worms is supported by localization of two of the major granule proteins, major basic protein (MBP) and eosinophil peroxidase (EPO), on and around species of trematodes, nematodes, and cestodes. In the case of filarial worms, MBP is deposited on degenerating microfilariae (mf) of Onchocerca volvulus. Here, we performed in vitro assays of the toxicity of four purified eosinophil granule proteins, namely, MBP, EPO, eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN), for the mf of Brugia pahangi and Brugia malayi. MBP, ECP, and EDN killed these worms in a dose-related manner although relatively high concentrations of EDN were necessary. EPO, in the presence of a H2O2-generating system and a halide, was the most potent toxin on a molar basis; here, the most potent halide was I- followed by Br- and Cl-. Surprisingly, EPO in the absence of H2O2 killed mf at concentrations comparable to those required for MBP and ECP. The toxicity of EPO + H2O2 + halide was inhibited by heparin, catalase, or 1% BSA, whereas the toxicity of EPO alone was inhibited only by heparin. Heparin also inhibited killing by both MBP and ECP. Despite the homology of ECP with certain RNases, placental RNasin, an RNase inhibitor, was unable to inhibit ECP-mediated toxicity. These results indicate that all of the eosinophil granule proteins are toxic to mf and they support the hypothesis that eosinophil degranulation causes death of mf in vivo.
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PMID:In vitro killing of microfilariae of Brugia pahangi and Brugia malayi by eosinophil granule proteins. 232 97

Recent evidence suggests a role for eosinophil granule proteins in contact-dependent antibody-mediated cytotoxicity. Cytolysis may involve a secretory phenomenon whereby granule proteins are released at the site of contact between eosinophil and target cells. Several basic proteins have been isolated from eosinophil granules, including the major basic protein, eosinophil cationic protein, eosinophil protein-X and eosinophil peroxidase. One of the major granule proteins of human eosinophils is the eosinophil cationic protein (ECP) which has been shown to damage schistosomula of Schistosoma mansoni at concentrations as low as 10(-7). Here, we describe the formation of functional channels by purified human ECP. The transmembrane pores formed by ECP are relatively voltage-insensitive and non-ion-selective, suggesting a role for channel formation by ECP in target cell damage mediated by eosinophils. Channel formation by granule proteins of immune effector cells may represent a general and effective mechanism of target cell killing.
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PMID:Mechanism of membrane damage mediated by human eosinophil cationic protein. 242 82

The inflammatory component of allergic rhinitis was studied by measuring the concentration and content of eosinophil cationic protein (ECP, specific for eosinophils) and myeloperoxidase (MPO, specific for neutrophils) in samples of nasal secretion from 20 pollen-allergic subjects. All secretion samples contained measurable concentrations of both proteins. The mean ECP concentrations on two occasions without pollen exposure were 950 and 1170 micrograms/l. The ECP concentration during the pollen season without any therapy (mean 1160 micrograms/l) did not differ significantly from the baseline values, but intranasal corticosteroid therapy resulted in a significant decrease (mean 530 micrograms/l). The concentration of MPO was about 10 times higher than that of ECP, but the changes in MPO were nonsignificant throughout the observation period. An inverse correlation was found between the threshold dose in histamine challenges and the ECP level expressed either as concentration or as content. Furthermore, the ECP concentration and content 1 day after a positive allergen challenge were both significantly correlated with the strength of the challenge reaction. Measurements of ECP in nasal secretions are useful for studying the presence and activity of eosinophils in the nasal mucosa, and may prove of value in clinical investigations on patients with allergic rhinitis.
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PMID:Eosinophil cationic protein and myeloperoxidase in nasal secretion as markers of inflammation in allergic rhinitis. 244 9

The eosinophil granule major basic protein, the eosinophil cationic protein, and the eosinophil-derived neurotoxin were found to be lytic for Trypanosoma cruzi trypomastigotes from blood, cell cultures, or insect vectors and for cultured amastigotes. The toxic effects of the major basic and cationic proteins were inhibited by the polyanions heparin and dextran sulfate, in keeping with the cationic nature of these proteins, or by heat denaturation, suggesting that molecular conformation was also relevant. The lytic activity of the neurotoxin was not inhibited by heating at 56 degrees C for 4 hr, establishing an additional difference with the eosinophil cationic protein. Heparin had only a slight inhibitory effect on the toxicity of the neurotoxin, and dextran sulfate was inactive even at 25 mg/ml. Although both the eosinophil cationic protein and the neurotoxin possess ribonuclease activity, only the toxicity of the latter was abolished by the ribonuclease inhibitor RNasin (Promega, Madison, Wisconsin) or by a competitive substrate, yeast ribonucleic acid. Eosinophil peroxidase significantly increased the extent of trypomastigote or amastigote killing by hydrogen peroxide in the presence of iodide. This effect was abrogated by sodium azide, bovine serum albumin, or gelatin, known inhibitors of the eosinophil peroxidase + halide + hydrogen peroxide system. These results suggest that the destruction of T. cruzi trypomastigotes and amastigotes by eosinophils may result from toxic mechanisms involving several granule proteins.
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PMID:Toxic effects produced or mediated by human eosinophil granule components on Trypanosoma cruzi. 245 44

The presence of receptors for IgE on eosinophils has drawn the attention on their direct participation in IgE-dependent hypersensitivity reactions. Surface IgE antibodies were detected on eosinophils from allergic patients. The addition of the specific allergen or anti-IgE antibodies to such purified eosinophils induced the release of eosinophil peroxidase, but not of eosinophil cationic protein. These findings associated with results obtained by using electron microscopy and immunogold staining of the various antibodies directed against the granule proteins allowed us to suggest a selectivity in the mediators released by eosinophils. In addition, preliminary results concerning the existence and the functional role of a receptor for IgA on eosinophils are reported, leading to the concept of a particular interaction of eosinophils with immunoglobulins present in the tissues and their participation in local immune responses.
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PMID:Selectivity of mediators released by eosinophils. 252 59

The number of eosinophils and the concentrations of eosinophil cationic protein (ECP), a specific granule constituent of eosinophil granulocytes, were measured in bronchoalveolar lavage (BAL) fluid from patients (n = 22) with idiopathic pulmonary fibrosis (IPF). The median recovery of eosinophils during lavage performance was 4% (range, zero to 49) of the nonepithelial cells and significantly increased compared with the recovery in healthy control subjects (less than 1%) and in control patients with sarcoidosis (1%; range, zero to 7). The median BAL fluid concentration of ECP was in IPF 13.3 micrograms/L (range, 2 to 118) and significantly increased compared with the concentrations in healthy control subjects (2.7 micrograms/L; range, less than 2 to 8) and in control patients (6.6 micrograms/L; range, less than 2 to 64). The BAL fluid concentrations of myeloperoxidase (MPO) were also significantly increased in IPF, indicating a local neutrophil activation. A significant correlation was found between BAL fluid ECP and MPO, suggesting a common activator of eosinophils and neutrophils. BAL fluid eosinophils and ECP correlated with the reduced diffusion capacity of the lung but not with vital capacity or forced expiratory volume. It is concluded that eosinophil activation is part of the inflammatory process in IPF. ECP and other cytotoxic eosinophil products may play a pathophysiologic role for the lung damage in this disease.
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PMID:The eosinophil component of the alveolitis in idiopathic pulmonary fibrosis. Signs of eosinophil activation in the lung are related to impaired lung function. 253 26

Platelet-activating factor (PAF) is a highly active mediator which has been implicated in allergic inflammation and bronchial asthma, possibly by interacting with eosinophils. We have examined the effect of PAF on activation of purified human eosinophils as measured by degranulation (eosinophil peroxidase, eosinophil cationic protein, arylsulfatase B, beta-glucuronidase, and alkaline phosphatase) and oxidative metabolism (superoxide anion production). PAF induced enzyme release at concentrations ranging from 1 pM to 10 microM in a rapid (t1/2 5 to 8 min), Ca2+-dependent and noncytotoxic manner from both the specific and small granules, whereas its biologic precursor and metabolite, lyso-PAF, had no effect. For all enzymes, maximal enzyme release occurred at 100 nM PAF with a mean ED50 value of 1.47 +/- 0.4 nM. At this concentration the mean percentage of total enzyme release by PAF from specific granules was 20.3 +/- 1.6% (17.9% for eosinophil peroxidase, 20.6% for beta-glucuronidase, 22.4% for alkaline phosphatase) and 28.8 +/- 2.2% from small granules (arylsulfatase B). Calcium ionophore A23187, PMA, and opsonized zymosan also induced eosinophil degranulation but their peak effect after 10-min incubation with maximal release 14.7%, 12.9%, or 14.1%, respectively, was lower when compared with PAF. Incubation of eosinophils with the PAF-antagonist WEB 2086 led to a parallel shift of the dose-response curve to the right, indicating a competitive antagonism. PAF also caused generation of superoxide anions by human eosinophils but this occurred at higher concentrations of PAF (1 microM to 30 microM) with an ED50 of 8.4 +/- 0.9 microM. Again, this effect was competitively inhibited by WEB 2086. These studies demonstrate that PAF activates human eosinophils to release granule constituents and generate superoxide anions. Since both PAF and eosinophil products are associated with pathogenesis of bronchial asthma our findings may be of particular pathophysiologic relevance.
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PMID:Stimulation of degranulation from human eosinophils by platelet-activating factor. 254 Nov 98

Cigarette smoking results in variable degrees of inflammation in the lower respiratory tract. Furthermore, smoking produces oxidant-mediated changes in the lung, important to the pathogenesis of emphysema. Since glutathione can neutralize reactive oxygen species and prevent peroxidation of unsaturated lipids, it may constitute an important component of the lung's defense against oxidant and inflammatory injury. In the present study, broncholaveolar lavage (BAL) was performed in 27 smokers, and the concentrations of total glutathione as well as the cellular and humoral markers of inflammatory activity were studied. There were significant correlations between total glutathione and neutrophils; two neutrophil granule components, myeloperoxidase and elastase; and chemotactic activity for neutrophils. Moreover, the total glutathione correlated with the eosinophil cationic protein (ECP), a granule constituent of the eosinophil, with two locally produced antiproteases, secretory leukocyte protease inhibitor (SLPI) and antichymotrypsin (ACHY), but not with an alpha 1-protease inhibitor and albumin. These data suggest that the total glutathione levels in BAL fluid may reflect a degree of oxidative and inflammatory stress caused by cigarette smoke, and they are therefore likely to contribute to the protection against this stress.
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PMID:Glutathione in bronchoalveolar lavage fluid from smokers is related to humoral markers of inflammatory cell activity. 261 93


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