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)

1. Biopsies of rectal mucosa were obtained for histology and enzyme analysis from 32 patients with inflammatory and functional bowel disorders, and the biopsies were classified morphologically as active colitis, quiescent colitis or normal. 2. Supernatant fractions of biopsy homogenates were assayed for their content of the proteolytic enzymes alpha-chymotrypsin, elastase and cathepsin D, and of protein, unsaturated vitamin B12-binding capacity, lysozyme, myeloperoxidase and N-acetyl-beta-glucosaminidase. 3. Mean unsaturated vitamin B12-binding capacity was significantly raised above normal in the active colitic mucosa, and mean lysozyme activity was raised above normal in both active and quiescent mucosae. 4. In active colitic mucosa there was no rise above normal in mean activities of any of the proteolytic enzymes, though a significant fall below normal occurred in mean N-acetyl-beta-glucosaminidase activity in the active colitic group.
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PMID:Mucosal enzymes in human inflammatory bowel disease with reference to neutrophil granulocytes as mediators of tissue injury. 22 86

A triple-bridge, indirect peroxidase-antiperoxidase method for demonstrating carcinoembryonic antigen (CEA) in frozen, ethanol-fixed or formalin-fixed, paraffin-embedded specimens was evaluated. Examination of 359 tissue specimens--234 malignant tumors, 37 benign neoplasms, 41 nonneoplastic diseased tissues, and 47 normal specimens--showed that CEA could usually be demonstrated in a group of cancers. We could detect CEA in carcinomas of the stomach, colon, rectum, pancreas, lung, and cervix. However, malignant tumors of the breast, prostate, kidney, larynx, brain, lymphoreticular system, soft tissues, and skin proved negative for CEA by the immunoperoxidase test. CEA could be detected in ethanol- or formalin-fixed sections. The only nonmalignant specimens showing CEA staining were a few benign tumors, the mucosae of some cases of colitis, and the resection margins of 2 cases of colon cancer; however, these were commonly very weak reactions. Measurement of tumor CEA content by radioimmunoassay revealed two causes for this relative specificity of the immunoperoxidase test for CEA:1) a quantitative difference existed in tissue CEA among the various specimens, and 2) the threshold for CEA staining in malignant specimens was usually above that in nonmalignant specimens. An analysis of the formalin-paraffin-treated sections showed that immunoperoxidase-tested CEA positivity reflected CEA levels in tissue of at least 3.0-5.0 mug/g; this permitted retrospective estimates of minimal tissue CEA concentrations in older histopathologic specimens by the immunoperoxidase reaction method. Formalin-paraffin-treated sections as old as 10 years still had demonstrable CEA. Although tumor CEA concentration correlated well with immunoperoxidase staining for CEA, plasma CEA titer did not necessarily reflect tumor CEA content. CEA positivity in primary and secondary tumors was strongly correlated; it was less strongly correlated with level of tumor differentiation.
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PMID:Carcinoembryonic antigen in histopathology: immunoperoxidase staining of conventional tissue sections. 79 93

The ability of nonsteroidal anti-inflammatory drugs to exacerbate experimental colitis, and the possible contributions of the "shunting" of arachidonate via the 5-lipoxygenase pathway, were investigated using a rat model in which colitis was induced by intracolonic administration of trinitrobenzene sulfonic acid in a vehicle of 50% ethanol. Twice daily treatment with indomethacin (0.1-1 mg/kg SC) during the first week after trinitrobenzene sulfonic acid/ethanol administration resulted in dose-dependent increases in the severity of colitis and in the incidence of mortality. Mortality was not observed in vehicle-treated colitic rats or in normal rats treated with indomethacin. Similar exacerbation of colitis was observed in rats treated with naproxen (5 mg/kg). Whereas treatment with a 5-lipoxygenase inhibitor, PF-5901 (100 mg/kg PO), resulted in a significant reduction of the severity of colitis, concomitant administration of PF-5901 and indomethacin (0.5 mg/kg SC) did not inhibit the exacerbative effects of the indomethacin in this model. In separate studies, administration of indomethacin was found to significantly increase colonic myeloperoxidase activity (a measure of tissue granulocyte numbers) and suppress colonic prostaglandin E2 synthesis, while not significantly affecting colonic leukotriene B4 synthesis. The effect on myeloperoxidase activity was seen during the period 21-24 hours after trinitrobenzene sulfonic acid ethanol administration, but not during the period 45-48 hours after induction of colitis. In in vitro studies using samples of inflamed colon and in vivo studies in which colonic eicosanoid production was measured by colonic dialysis, inhibition of prostaglandin E2 synthesis was not accompanied by significant changes in leukotriene B4 synthesis. These results suggest that inhibitors of colonic prostaglandin synthesis can markedly exacerbate colitis, and that this effect is unrelated to alterations in colonic leukotriene B4 synthesis. Endogenous prostaglandins may exert anti-inflammatory effects during the acute stages of colitis.
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PMID:Exacerbation of experimental colitis by nonsteroidal anti-inflammatory drugs is not related to elevated leukotriene B4 synthesis. 130 57

In inflammatory bowel disease, prostaglandins are mucosal protective whereas leukotrienes are proinflammatory. Recent evidence suggests that the formation and action of leukotrienes are calcium-dependent, whereas the formation and action of prostaglandins are not. To examine the possibility that, because of differential regulation of arachidonic acid metabolism, calcium channel blockade might alter mucosal eicosanoid synthesis and accelerate healing during inflammatory bowel disease, we treated a 4% acetic acid-induced colitis model with verapamil and/or misoprostol and determined the effects on colonic macroscopic injury, mucosal inflammation as measured by myeloperoxidase activity, in vivo intestinal fluid absorption, and mucosal prostaglandin E2 and leukotriene B4 (LTB4) levels as measured by in vivo rectal dialysis. In colitic animals, verapamil treatment significantly improved colonic fluid absorption and macroscopic ulceration. This mucosal-protective effect of verapamil occurred in the presence of a twofold reduction in mucosal LTB4 synthesis. In noncolitic animals, verapamil alone had no effect on in vivo fluid absorption, macroscopic ulceration, or myeloperoxidase activity but did induce a threefold reduction in LTB4 synthesis in addition to shifting arachidonic acid metabolism towards a sixfold stimulation of prostaglandin E2 synthesis. Our results show that, when administered before the experimental induction of colitis, the calcium channel blocker, verapamil, has a mucosal-protective effect that occurs as a consequence of reduced mucosal leukotriene synthesis and increased prostaglandin synthesis. This differential regulation of arachidonic acid metabolism may play an important role in the development of novel therapeutic agents for inflammatory bowel disease.
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PMID:Verapamil alters eicosanoid synthesis and accelerates healing during experimental colitis in rats. 131 74

Two models of colitis produced in rats that have received significant attention over the past few years are the acetic acid and trinitrobenzene sulfonic acid (TNBS) models. The objective of this study was to quantify and compare the temporal relationship among mucosal permeability, epithelial injury, and inflammation induced by acetic acid, ethanol (vehicle), ethanol plus TNBS (unbuffered, pH 1.0), and ethanol plus TNBS (pH 7.4). Data obtained show that the inflammation induced by these four irritants results from caustic injury to the colonic epithelium and interstitium as measured by the rapid and dramatic increases in mucosal permeability and tissue water content as well as by histological analysis. The injurious nature of TNBS was confirmed in a separate series of studies showing that buffered TNBS (pH 7.4), in the absence of ethanol, is toxic to cultured rat intestinal epithelial cell monolayers. Only after 1-2 days of the initial insult, were signs of classical inflammation observed, including increases in colonic myeloperoxidase activity (neutrophil infiltration) and colon weight as well as hyperemia and mucosal ulcerations. Although ethanol plus TNBS (pH 1.0 or 7.4) tended to produce higher mucosal permeabilities (epithelial cell injury) at 1-2 weeks after the enemas than acetic acid or ethanol groups, only the ethanol plus TNBS (pH 7.4) permeabilities were found to be significantly enhanced. In addition, all four groups showed significant elevations in colonic myeloperoxidase activity and colon weight at 1-2 weeks after enema. It is suggested that these models of colitis are useful to study events that occur at the time of inflammation and repair. However, these models may have significant limitations in understanding events that initiate inflammation of the intestine in human inflammatory bowel disease.
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PMID:A comparative analysis of two models of colitis in rats. 131 49

The role of neutrophils in the pathogenesis of acute colitis was investigated using a rabbit model. Colitis was induced by intracolonic administration of trinitrobenzene sulfonic acid in 30% ethanol. Myeloperoxidase activity was measured at various times after induction of colitis as an index of neutrophil infiltration, and this was confirmed by histology. The permeability of the colonic epithelium to [51Cr]EDTA was also measured at various times after induction of colitis. The most marked increase in neutrophil infiltration of the colon occurred during the period 3-6 h after induction of colitis. This was also the period in which the greatest increase in colonic permeability was observed. Pretreatment with a monoclonal antibody (IB-4) directed against the leukocyte adhesion molecule, CD18, markedly suppressed neutrophil infiltration into the colonic tissue after induction of colitis. This pretreatment also significantly reduced the extent of epithelial injury. Administration of IB-4 to rabbits 12 h after induction of colitis resulted in a rapid decline in tissue myeloperoxidase activity. When measured 12 h after IB-4 administration (3 mg/kg), colonic myeloperoxidase activity was reduced by about 80% compared to the control group treated with the vehicle. These results are consistent with the hypothesis that neutrophils contribute significantly to the epithelial dysfunction that characterizes colitis and suggest that antibodies directed against adhesion molecules may represent a novel approach to the treatment of intestinal inflammatory disorders.
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PMID:Prevention and reversal of experimental colitis by a monoclonal antibody which inhibits leukocyte adherence. 132 82

The implication of leukotrienes as mediators of inflammation and recent evidence that prostaglandin analogues provide a beneficial effect during experimental colitis led to the speculation that (i) leukotrienes may be injurious and (ii) prostaglandins may be protective to colonic mucosa. Using a 2% acetic acid induced rat colitis model, we administered specific cyclooxygenase (indomethacin) and leukotriene biosynthesis inhibitors (MK-886) to examine the effect of endogenous prostaglandins and leukotrienes on colonic macroscopic injury, mucosal inflammation as measured by myeloperoxidase activity, net in vivo intestinal fluid absorption, and colonic PGE2 and LTB4 levels as measured by in vivo rectal dialysis. Indomethacin treatment prior to induction of colitis reduced endogenous mucosal PGE2 levels and exacerbated macroscopic ulceration and net fluid absorption. Addition of the exogenous PGE1 analogue misoprostol to the indomethacin-exacerbated colitis completely healed colonic macroscopic ulceration and inflammation but only partially improved fluid absorptive injury. The specific leukotriene biosynthesis inhibitor MK-886 administered prior to induction of colitis healed macroscopic ulceration and inflammation but not fluid absorptive injury. This mucosal reparative effect of MK-886 occurred at a dose that reduced colonic LTB4 synthesis while concomitantly enhancing PGE2 levels. Combining MK-886 with misoprostol treatment improved not only macroscopic ulceration and inflammation but also provided a synergistic effect that maintained net colonic fluid absorption at noncolitic control levels. These studies suggest that, during the induction of experimental colitis, endogenous prostaglandins play a pivotal role in providing a mucosal healing effect, and that leukotriene biosynthesis inhibitor may manifest part of its beneficial effect by shifting arachidonic acid metabolism towards production of prostaglandins.
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PMID:Indomethacin worsens and a leukotriene biosynthesis inhibitor accelerates mucosal healing in rat colitis. 133 Feb 56

A standard colitic lesion was induced in male BKA mice by intrarectal administration of butyric acid (7.5%, 0.1 ml, 10 sec contact). Animals were killed after 5 h and the 'colitic score', increase in colonic tissue water ('oedema') and colonic tissue content of myeloperoxidase (MPO, a marker for neutrophils) were determined. Drug was administered intrarectally in 0.2 ml saline 20 min before colitis induction. In colitic animals given vehicle alone, all these parameters increased (P less than 0.05) compared to the non-colitic controls. In colitic animals given 16,16-dimethyl PGE2 (0.2-20000 micrograms/kg), colitic score was reduced (P less than 0.05) at all dose levels when compared with vehicle-treated colitic animals. The oedema and MPO showed a dose-related reduction (r = -0.895 and -0.904 respectively). In mouse colon 16,16-dimethyl PGE2 showed a protective action against butyric acid-induced colitic damage.
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PMID:Inhibition of butyric acid-induced colitis in mice by 16,16-dimethyl prostaglandin E2. 133 52

The mucosal protective prostaglandin analogs misoprostol, enisoprost, and SC-46275 (the 17E-18-cyclopentenyl analog of enisoprost) were tested in mouse and rat colitis induced by the intrarectal instillation of dilute acetic acid. Colitis was assessed by histology and colonic levels of myeloperoxidase (a neutrophil marker enzyme). When given as enemas 30 min ahead of colitis induction, 15(R)-15-methyl-PGE2 (arbaprostil) and 15(S)-15-methyl-PGE1 were inactive; however, misoprostol, enisoprost, and SC-46275 protected against colonic inflammation with ED50 values of 24, 12 and 1.3 micrograms/kg, respectively, in rats and 11, 5, and 1 micrograms/kg, respectively, in mice. These compounds may have utility in the medical management of human inflammatory bowel disease.
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PMID:Mucosal protective activity of prostaglandin analogs in rodent colonic inflammation. 133 49

Intracolonic administration of trinitrobenzene sulfonic acid in ethanol results in the development of colitis in the rat. Previous studies have demonstrated that the severity of this colitis can be markedly reduced by repeated treatment with inhibitors of leukotriene synthesis, although such treatment does not appear to affect the initial migration of granulocytes into the colon. The present study evaluated the contribution of leukotrienes and interleukin-1 to the recruitment of granulocytes into the colon during the first 12 h after induction of colitis. Rats were treated with a leukotriene synthesis inhibitor (PF-5901), a leukotriene B4 receptor antagonist (SC-41930), an IL-1 receptor antagonist or a corticosteroid (prednisolone) prior to induction of colitis. Granulocyte infiltration was assessed by measurement of colonic myeloperoxidase activity and severity of colonic damage was blindly scored. Despite significant inhibition of leukotriene synthesis, PF-5901 did not affect colonic myeloperoxidase activity or the severity of colonic injury at any time point. Similarly, SC-41930 was without significant effect. However, both the interleukin-1 receptor antagonist and prednisolone significantly reduced colonic myeloperoxidase activity (by approximately 50%) and severity of colonic damage at 6 h after induction of colitis, without significantly affecting colonic leukotriene synthesis. These beneficial effects were no longer apparent at 12 h after induction of colitis. This study demonstrates that the infiltration of granulocytes into the colon during the acute phase of colitis in the rat occurs independent of leukotriene synthesis and appears to be at least in part attributable to interleukin-1.
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PMID:Granulocyte infiltration in experimental colitis in the rat is interleukin-1 dependent and leukotriene independent. 133 73


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