Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

TEMPOL, a cyclic nitroxide stable radical blocks biological damage by breaking chain reactions through termination reaction with free radicals, and by inhibiting the catalytic effect of transition metals. This study tested its protective effect on two models of experimental colitis as free radicals play an important part in their pathogenesis. TEMPOL was given intragastrically immediately after induction of colitis with acetic acid or trinitrobenzene sulphonic acid (TNB) and mucosal damage was assessed one, three, or seven days later. Cellular partition of TEMPOL was determined by electron paramagnetic resonance spectroscopy. In vitro experiments showed that TEMPOL immediately penetrates colonic mucosa and, following its intragastric administration, it persists in both gastric and colonic mucosa for several hours. Intragastric administration of TEMPOL, 0.5 g/kg/bw, immediately after intracaecal administration of 5% acetic acid significantly decreased mucosal lesion area, myeloperoxidase activity, and leukotriene B4 and C4 generation when assessed 24 hours after damage induction. Intragastric administration of TEMPOL, 0.5 g/kg/bw, immediately after intracolonic administration of 30 mg TNB in 0.25 ml 50% ethanol, and once daily thereafter, significantly decreased mucosal lesion area assessed after one, three, and seven days, having no effect on LTC4 generation and affecting colonic weight, myeloperoxidase activity, and LTB4 generation only sporadically. In conclusion, TNB and acetic acid induced colitis can be pharmacologically manipulated by TEMPOL. TEMPOL may be beneficial in the treatment or prevention of inflammatory bowel disease.
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PMID:A stable nitroxide radical effectively decreases mucosal damage in experimental colitis. 759 Apr 35

Leukotriene B4 (LTB4) and 12(R)-hydroxyeicosatetraenoic acid [12(R)-HETE] are proinflammatory products of arachidonic acid metabolism that have been implicated as mediators in a number of inflammatory diseases. When injected intradermally into the guinea pig. LTB4 and 12(R)-HETE elicit a dose-dependent migration (chemotaxis) of neutrophils (PMNs) into the injection sites as assessed by the presence of a neutrophil marker enzyme myeloperoxidase. SC-41930 (7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxyl]-3,4-dihy dro-8-propyl-2H - 1-benzopyran-2-carboxylic acid), a first-generation LTB4 receptor antagonist, inhibited the chemotactic actions of LTB4 when given orally with an ED50 value of 1.7 mg/kg. The second-generation LTB4 receptor antagonist, SC-53228 [(+)-(S)-7-(3-(2-(cyclopropylmethyl)-3-methoxy-4- [(methylamino)carbonyl]phenoxy)propoxy)-3,4-dihydro-8-propyl-2H-1- benzopyran-2-propanoic acid], inhibited LTB4-induced chemotaxis when given intragastrically with an ED50 value of 0.07 mg/kg. Furthermore, SC-53228 inhibited 12(R)-HETE-induced granulocyte chemotaxis with an oral ED50 value of 5.8 mg/kg. When dosed orally over a range of 0.03-100 mg/kg, SC-53228 gave Cmax plasma concentrations of 0.015-41.1 micrograms/ml. SC-53228 inhibited LTB4-primed membrane depolarization of human neutrophils with an IC50 value of 34 nM. As a potent LTB4 receptor antagonist, SC-53228 may well have application in the medical management of disease states such as asthma, rheumatoid arthritis, inflammatory bowel disease, contact dermatitis, and psoriasis, in which LTB4 and/or 12(R)-HETE are implicated as inflammatory mediators.
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PMID:Antiinflammatory effects of second-generation leukotriene B4 receptor antagonist, SC-53228: impact upon leukotriene B4- and 12(R)-HETE-mediated events. 760 5

The transendothelial migration of leukocytes in many inflammatory responses is now believed to be dependent on the interaction of leukocyte and endothelial cell-derived adhesion molecules. To examine the role of intercellular adhesion molecule-1 (ICAM-1) in the development of inflammation in a rat model of colitis, we investigated the effects of antibodies to rat ICAM-1 given 24 hrs after inflammation was induced by acetic acid. Antibodies to rat ICAM-1 substantially ameliorated the inflammatory response as indicated by a reduction in gross inflammatory characteristics, tissue/body weight ratio, myeloperoxidase activity and superoxide levels. The results demonstrate that ICAM-1 plays an important role in the development of inflammatory bowel disease in rats. The use of antibodies to ICAM-1 to inhibit the adherence of leukocytes to endothelium, may be of potential therapeutic value in the treatment of inflammatory bowel disease in man.
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PMID:Antibodies to intercellular adhesion molecule-1 ameliorate the inflammatory response in acetic acid-induced inflammatory bowel disease. 761 34

Administration of a hapten together with a barrier breaker, such as ethanol, into the colon of a rat results in extensive mucosal injury and inflammation that bears some similarity to the colonic inflammation characterizing inflammatory bowel disease in humans. This inflammation and injury gradually subsides over the weeks after its induction. We have attempted to determine whether this colitis can be "reactivated" by administration of the hapten systemically weeks after its initial intracolonic administration. Six weeks after intracolonic administration of trinitrobenzene sulfonic acid (the hapten) in a vehicle of 50% ethanol, most of the colonic injury and inflammation had subsided. Intravenous administration of the hapten at 24-h intervals over 3 days resulted in reactivation of the colitis, with significant increases in macroscopic and histological damage scores (mucosal injury and inflammation) and a significant increase in granulocyte infiltration, as measured by tissue myeloperoxidase (MPO) infiltration, as measured by tissue myeloperoxidase (MPO) activity. The increase in MPO activity occurred only in the region previously exposed to the hapten. Intravenous administration of saline did not reactivate the colitis, nor did intravenous administration of the hapten to rats previously treated intracolonically with saline or the ethanol vehicle. Reactivation of colitis by hapten administration was not accompanied by activation of mucosal mast cells. Treatment with dexamethasone prevented the increase in colonic damage score and MPO activity elicited by intravenous hapten administration. Cyclosporin A reduced MPO activity, and 5-aminosalicylic acid reduced the colonic damage score, whereas lidocaine and two inhibitors of leukotriene synthesis did not significantly affect either of these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reactivation of hapten-induced colitis and its prevention by anti-inflammatory drugs. 763 88

The influx of monocytes and neutrophils into the inflamed tissue could be an important aspect in the pathogenesis of inflammatory bowel disease (IBD). A membrane protein involved in the monocyte/neutrophil adherence to endothelium is CD11b/CD18 or alpha M beta 2 (complement receptor type 3 = CR3). In the present study the role of CD11b/CD18 in experimental IBD was studied by treatment with ED7 and OX42, two MoAbs against CD11b/CD18. Colitis was induced in rats by a single, rectal administration of 30 mg 2,4,6-trinitrobenzene sulfonic acid (TNBS) dissolved in ethanol 30%. Two hours before and 3 days after induction of colitis, the animals were given an i.v. dose of 0.5 mg of either ED7 or OX42 in 1 ml PBS. Controls received PBS or an irrelevant MoAb. Four days after the last treatment with the antibodies, the rats were killed, and macroscopic damage scores of the colon were determined. Macrophages and granulocytes were studied by immunohistochemistry and quantified by Interaktives Bild Analysen System (IBAS), and myeloperoxidase (MPO) activity in colonic tissue was measured. After treatment with ED7 and OX42 the mean damage score of the colon was reduced from 4.2 in IBD animals to 1.0 and 1.3, respectively. Smaller areas of ulcerations and a decrease in the number of ulcerations were observed compared with PBS-treated rats. Furthermore, the amount of infiltrating monocytes and leucocytes in the submucosa was enormously reduced, as well as MPO activity in the colonic tissue. These results show that treatment with MoAbs against CD11b/CD18 reduces clinical signs of experimental IBD in rats by a partial blockade of infiltrating macrophages and granulocytes.
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PMID:Anti-CD11b/CD18 antibodies reduce inflammation in acute colitis in rats. 764 20

Nitric oxide synthesis appears to be elevated in inflammatory bowel disease, but little is known about the contribution of nitric oxide to the pathophysiological process. To address this issue, we included the nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) in the drinking water (10 or 100 micrograms/ml) of guinea pigs immediately after induction of ileitis by intraluminal trinitrobenzenesulfonic acid (TNBS 30 mg/kg in 50% ethanol). Guinea pigs were sacrificed after 7 days of this ad libitum treatment. Control groups received either intraluminal TNBS, saline or ethanol (TNBS vehicle) without L-NAME or TNBS + D-NAME (100 micrograms/ml), the inactive enantiomer. Immediately before sacrifice, guinea pigs were anesthetized and saline was administered intraluminally at the site of TNBS or saline administration and then withdrawn after 30 min. Change in lavage volume and lavage protein and nitrite levels were measured, as well as tissue myeloperoxidase and bowel wall thickness (weight/length). TNBS administration resulted in an increase in tissue thickness, myeloperoxidase and lavage protein and nitrite levels over sham controls. Oral L-NAME prevented these responses. D-NAME was ineffective with the exception of tissue thickness. The change in intestinal lavage fluid volume indicated that reabsorptive processes dominated in the sham and TNBS + L-NAME groups, and secretory responses predominated in TNBS and TNBS + D-NAME animals. In contrast to TNBS-induced ileitis, L-NAME (100 micrograms/ml, p.o., 7 days) administration to intact animals resulted in a local inflammatory response (i.e., increased myeloperoxidase activity and a fluid secretory response).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Amelioration of chronic ileitis by nitric oxide synthase inhibition. 767 45

To determine if epithelial lipoxygenases are regulated by mucosal inflammation, we examined the distribution of arachidonate 12-lipoxygenase in healthy colonic tissue and in involved and uninvolved sections of colon with inflammatory bowel disease. Immunohistochemistry of formaldehyde-fixed, paraffin-embedded intestinal tissue using two anti-12-lipoxygenase antibodies and indirect biotin-avidin-peroxidase detection demonstrated that, in contrast to tissue from normal colon (n = 8), in which 12-lipoxygenase antigen was undetectable in mucosal epithelial cells, the mucosal and glandular epithelium of inflamed colon in ulcerative colitis (n = 4) or Crohn's disease (n = 4) exhibited markedly positive immunostaining with anti-12-lipoxygenase antibodies. Immunoblotting of whole cell extracts with anti-12-lipoxygenase antibodies showed immunoperoxidase staining of a single protein band that comigrated with purified 12-lipoxygenase (in relative molecular weight: M(r) = 72,000) in mucosal samples from inflamed colon from subjects with ulcerative colitis or Crohn's disease but no comparable band in samples from uninvolved sections of the same colons or from colons of subjects without inflammatory bowel disease. Assays of 12-lipoxygenase activity indicated a corresponding increase in enzymatic activity in the same mucosal samples. The increased levels of 12-lipoxygenase antigen in the mucosal and glandular epithelial cells in regions of colon affected by inflammatory bowel disease, the corresponding increases in 12-lipoxygenase activity, and the absence of detectable 12-lipoxygenase antigen or enzymatic activity in the same cell types in noninflamed colonic tissue all suggest that epithelial cell 12-lipoxygenase is induced by local mediators of colonic inflammation.
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PMID:Induction of epithelial arachidonate 12-lipoxygenase at active sites of inflammatory bowel disease. 767 52

Autoimmune diseases, such as rheumatoid arthritis and inflammatory bowel disease are characterized by chronic inflammatory responses resulting in tissue damage. These diseases have a number of common denominators including: abnormal cytokine expression, aberrant antigen-antibody complexes, T cell anomalies, and increased numbers of neutrophils and macrophages. We propose that the interaction between neutrophils and macrophages induces a state of chronic inflammation which contributes to the disease state. One of the central players in this scenario is myeloperoxidase (MyPo). This enzyme functions in the 'cytotoxic triad' and is involved in cell killing. Studies done by the present investigators have known that MyPo, which is released from neutrophils, induces macrophages to secrete interleukin-1, interferon alpha beta and tumor necrosis factor alpha. Furthermore, our studies have suggested a major immunoregulatory role of this enzyme. We propose that the release of MyPo from neutrophils and subsequent binding to macrophages initiates a cascade of events which enhance the production of reactive oxygen intermediates and cytokine expression resulting in the chronic inflammatory state associated with autoimmune diseases.
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PMID:Neutrophil-macrophage interaction: a paradigm for chronic inflammation. 777 4

Antineutrophil cytoplasmic autoantibodies (ANCA) have been used as markers of systemic vasculitides, including microscopic polyarteritis (MPA) and Wegener's granulomatosis. The diagnostic potential of ANCA assays together with antibodies against the neutrophil enzymes myeloperoxidase (MPO) and proteinase 3 for detecting a systemic vasculitis was tested in a Chinese patient population. 672 sera were received for ANCA assay, and ANCA detected by indirect immunofluorescence was positive in 73 sera from 42 patients. Of the 42 patients, 3 had cytoplasmic ANCA, while 39 had a perinuclear pattern. There was no patient with Wegener's granulomatosis. Two cytoplasmic ANCA positive patients suffered from ulcerative colitis. Another cytoplasmic ANCA positive patient was a carrier of human immunodeficiency virus. Of the 39 perinuclear ANCA positive patients, 10 had MPA. Eight of them were tested for anti-MPO antibody, and all were positive. Other immune disorders that were perinuclear ANCA positive included: 13 patients with systemic lupus erythematosus, 3 with mixed connective tissue disease, 1 with Goodpasture's syndrome, 2 with inflammatory bowel disease, and 2 patients with IgA nephropathy. Anti-MPO antibody was not specific for MPA, and 7 out of the 13 patients with systemic lupus erythematosus were anti-MPO antibody positive. Our study suggests that ANCA and anti-MPO antibody are not specific for MPA in a Chinese population. They would alert the clinician of the possibility of vasculitis, but a clinicopathological correlation is essential in making the diagnosis.
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PMID:Use of antineutrophil cytoplasmic autoantibodies in diagnosing vasculitis in a Chinese patient population. 791 85

Although oral glucocorticoids are the treatment of choice for moderate to severe ulcerative pancolitis, their systemic side effects and adrenal suppression account for considerable morbidity. An oral glucocorticoid-conjugate (prodrug), budesonide-beta-D-glucuronide, which is not absorbed in the small intestine but is hydrolysed by colonic bacterial and mucosal beta-glucuronidase to release free budesonide into the colon was synthesised. The objective of this study was to compare treatment with budesonide-beta-D-glucuronide with treatment with free budesonide by examining: (1) the healing of experimental colitis and (2) the extent of adrenal suppression. Pancolitis was induced with 4% acetic acid. Animals were then randomised to receive oral therapy for 72 hours with (1) budesonide-beta-D-glucuronide, (2) free budesonide, or (3) vehicle. Drug efficacy and colitic healing was determined by measuring gross colonic ulceration, myeloperoxidase activity, and in vivo colonic fluid absorption. Adrenal suppression was determined by measuring plasma adrenocorticotrophic hormone and serum corticosterone. Vehicle-treated colitis animals had gross ulceration, increased myeloperoxidase activity, and net colonic fluid secretion. Treatment with oral budesonide-beta-D-glucuronide accelerated all measures of colitis healing at a fourfold lower dose than did free budesonide. Furthermore, treatment with budesonide-beta-D-glucuronide did not result in adrenal suppression whereas free budesonide treatment did. A newly synthesised orally administered glucocorticoid-conjugate accelerates colitis healing with limited adrenal suppression. Development of an orally administered colon-specific steroid delivery system represents a novel approach to inflammatory bowel disease treatment.
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PMID:A budesonide prodrug accelerates treatment of colitis in rats. 795 2


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