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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunologically mediated expulsion of Trichinella spiralis infective larvae in the rat was used as a model to test the hypothesis that intestinal anaphylaxis induced by parasite antigen causes ion transport alterations in small intestinal epithelium, and that the small intestinal epithelium, by altering its physiologic state in response to mast cell-derived mediators, functions as an effector tissue in the expulsion process. Experimental results demonstrated that the rapid rejection response and antigen-inducible changes in net intestinal ion transport acquired through active immunization were transferable with serum containing a high titer of anti-trichinella homocytotropic antibody, as measured by the PCA test. Neither response was expressed in nonimmune hosts nor in recipients of serum in which the PCA-detectable antibody was reduced by heat treatment. Net ion transport by jejunal epithelium of both actively and passively immunized rats was measured in Ussing chambers by using the electrical correlate, short circuit current (Isc). Involvement of chloride secretion in antigen-induced alterations in Isc was deduced from the use of chemical agents that effectively and specifically blocked the antigen-induced Cl- secretory response. The results implicate anaphylaxis in both rapid worm rejection and altered epithelial ion transport.
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PMID:Anaphylaxis-mediated epithelial Cl- secretion and parasite rejection in rat intestine. 380 21

The antigenicity of difluprednate, phototoxicity and photocontact sensitivity of difluprednate ointment and cream were studied in guinea pigs and mice. The results in this study were as follows. Guinea pigs immunized with difluprednate emulsified with Freund's complete adjuvant did not exhibit the systemic anaphylaxis and the delayed type hypersensitivity by the elicitation with either difluprednate alone or difluprednate-BSA conjugate. The antisera obtained from these guinea pigs did not show the positive response in the homologous 4-hour PCA reaction and the passive hemagglutination test against the challenge of the same antigens described above. In the maximization test, guinea pigs immunized with difluprednate did not show the contact sensitivity when elicited with difluprednate suspended in saline. Guinea pigs applied difluprednate ointment did not show positive contact sensitivity by the elicitation with difluprednate ointment and ointment base. The antisera obtained from mice immunized with difluprednate and difluprednate-OVA conjugate absorbed to Al (OH)3 gel did not give the positive response in the 72-hour PCA reaction against the challenge of either difluprednte alone or difluprednate-BSA conjugate. In the phototoxicity and photocontact sensitivity test, 0.05% difluprednate ointment and 0.05% difluprednate cream did not show positive reactions in guinea pigs, although very slight erythema was caused by the primary irritancy of cream base, with or without irradiation of ultraviolet ray (320-400 nm).
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PMID:[Studies on antigenicity of difluprednate--antigenicity of difluprednate, phototoxicity and photocontact sensitivity of difluprednate ointment and cream]. 403 3

Immunization of rabbits as neonates and periodically thereafter has been shown to induce the long-term preferential production of specific IgE antibodies. Specific IgG antibodies are not detected in the majority (greater than 70%) of rabbits when classical immunological detection techniques are used, including heterologous PCA in guinea-pig skin. Nevertheless, in this study we demonstrate that all rabbits neonatally immunized to the antigen horseradish peroxidase (HRP) do produce low levels of specific IgG antibody detectable by an ELISA technique. Serum levels of anti-HRP IgG were found to be log normally distributed, with a geometric mean for the heterologous PCA-negative sera of 31.6 X/divided by 2.69 micrograms/ml. Serum anti-HRP IgE levels (log2 homologous PCA titres) are bimodally distributed. Specific IgG and IgE levels in individual rabbits have a significant direct relationship. Six heterologous PCA-negative and seven heterologous PCA-positive rabbits were challenged intravenously with HRP. All of the respiratory and circulatory alterations typical of IgE anaphylaxis occurred in every challenged rabbit. Regression analysis of percentage changes in the physiological variables vs log specific IgE level indicated that none of the changes was either directly or inversely related to the specific IgG levels. Also the mean changes of the heterologous PCA-positive vs negative rabbits did not differ significantly. Thus, we could find no evidence for either a blocking or enhancing effect of the specific IgG antibodies (range 10-529 micrograms/ml serum) on the IgE-induced anaphylactic reaction.
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PMID:Effect of specific IgG on IgE-induced systemic anaphylaxis in the rabbit. 404 97

Antibody capable of sensitizing rabbit skin for passive cutaneous anaphylaxis is produced in the rabbit as early as 6 to 7 days following antigenic stimulation. It reaches peak activity around the 9th day and is gone by the 3rd wk. The antibody is heat labile, sensitive to treatment with mercaptoethanol, non-precipitating and does not fix complement. In order to demonstrate PCA activity a latent period is required of from 48 to 72 hr after introduction of the antibody into the rabbit's skin; the activity can persist for at least 17 days. It has a faster electrophoretic mobility than rabbit gammaG-globulin, and is eluted somewhat earlier than gammaG-globulin from Sephadex G-200, although distinctly after gammaM-globulin. No relationship was demonstrated between the rabbit PCA activity and the hemagglutinating activity found in the same sera. The rabbit anaphylactic antibody differs in almost all properties studies from the rabbit 7S antibody capable of sensitizing guinea pigs for PCA which arises at the same time. This latter antibody found early in immunization had properties which were indistinguishable from those described for the rabbit 7S antibody giving PCA in the guinea pig found in late hyperimmune sera.
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PMID:Rabbit anaphylactic antibody. 593 18

Derivatives substituted at position 2 of 4-oxochinazolin as well as derivates of oxochinazolin-3-yl-benzoic acid and 4-oxochinazolin-3-yl-acetic acid had been tested for their antianaphylactic activities in the passive (PCA) and/or active cutaneous anaphylaxis (ACA) in rats. At i.p. administration (ACA) or intracutaneous (i.c.) administration (PCA) most of the derivates displayed a moderate antianaphylactic activity which et best could be compared to the theophylline activity. Only the free acids of the 4-oxochinazolin-3-yl-acetic acid derivatives were active at i.c. administration. All compounds tested remained inactive at p.o. administration.
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PMID:[The antianaphylactic effect of derivatives of 4-oxoquinazoline, 4-oxoquinazol-3-yl-benzoic acid and 4-oxoquinazol-3-yl-acetic acid in the rat]. 609 54

4-[[(p-Chlorophenoxy)acetyl]amino]-5-chloro-2-methoxy-N-[2-(diethylamino)ethyl]benzamide (cloxacepride, 1), exhibited substantial oral antiallergic potential in a reaginic PCA test in rats over a wide range of antigenic challenge times. Available reference compounds with oral activity, such as doxantrazole and 7-(2-hydroxyethoxy)-9-oxoxanthene-2-carboxylic acid (AH 7725, 4), were active only when administered 15 min before challenge: 4, in particular, was not consistent in effect. Oral ED50 values for cloxacepride of 46-49 mg/kg were comparable to that of theophylline and to an intravenous injection of 2 mg/kg of disodium chromoglycate (DSCG) followed by immediate challenge. Following oral ED50 doses, 1 showed slower onset and longer duration of action than theophylline. The absence of inhibition of systemic anaphylaxis and of antihistaminic activity suggests specific effect or reaginic antigen antibody reactions. Structure-activity relationships of various chemical modifications were investigated and discussed in terms of essential substituents.
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PMID:Cloxacepride and related compounds: a new series of orally active antiallergic compounds. 613 32

The effects of (+/-)-2-[p-(2-thenoyl)phenyl] propionic acid (suprofen), a new anti-inflammatory agent, on experimental allergic reaction and antibody formation were examined. The action was compared with those of ketoprofen, ibuprofen, indomethacin, tranilast, chlorpheniramine, prednisolone and/or cyclophosphamide. Suprofen inhibited homologous PCA in rats, immunological histamine release from rat peritoneal mast cells and guinea pig lung tissues, Forssman cutaneous vasculitis (FCV) and the Arthus reaction in guinea pigs. The potency for inhibition of the PCA reaction was similar to that of ketoprofen and more potent than ibuprofen and trailast. As for the release of anaphylactic mediators, suprofen was less potent than tranilast in terms of histamine release, but not the release of the slow reacting substance of anaphylaxis (SRS-A). Suprofen inhibited FCA more potently than other nonsteroidal anti-inflammatory drugs (NSAID). The inhibition of the Arthus reaction by suprofen was similar to those of other NSAID and prednisolone. Suprofen hardly affected delayed hypersensitivity in guinea pigs and antibody (IgM or IgE) formation in mice or rats.
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PMID:Effect of (+/-)-2-[p-(2-thenoyl)phenyl] propionic acid (suprofen) on experimental allergic reactions. 614 45

A new series of orally active mediator release inhibitors, pyrido[3',2':4,5]thieno[3,2-d]-N-triazines, was synthesized and evaluated for antiallergic activity. Several products showed high activity as inhibitors or wheal information in the rat passive cutaneous anaphylaxis screen and as inhibitors of histamine release from passively sensitized rat mast cells. Many compounds were orally active in the PCA test. The most potent compound, 7-phenylpyrido-[3',2':4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)- one (10) with an I50 value of 0.05 microM, was 60 times more potent than disodium cromoglycate (DSCG) in the RMC assay.
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PMID:Pyrido[3',2':4,5]thieno[3,2-d]-N-triazines: a new series of orally active antiallergic agents. 615 Jan 14

In vivo and in vitro allergenic activities of allergen and allergoid preparations from partially purified timothy pollen extract were measured in three different systems. In heterologous PCA titration, the allergen preparation was found to be 32 times more allergenic than the allergoid preparation. By intravenous chaled that treatment of allergen preparations with formaldehyde led to a preparation with the properties of an allergoid. In addition, it was found that the carbohydrate fraction of the refined allergen preparation of timothy a reduction in blood pressure. Thus, the allergen preparation was at least 50 times more potent in inducing systemic anaphylaxis in sensitized rats than the allergoid preparation. In the histamine release assay of grass-sensitive human leukocytes, approximately 1,000 times more allergoid protein than allergen protein was required to achieve 30% histamine release. Although to different degrees, in all three test systems in could be demonstrated that treatment of allergen preparations with formaldehyde led to a preparation with the properties of an allergoid. In addition, it was found that the carbohydrate fraction of the refined allergen preparation of timothy pollen decreased the blood pressure even in nonsensitized animals. The effect of this carbohydrate fraction on blood pressure was immediate but short-lived and immunologically nonspecific.
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PMID:Studies on allergen and allergoid preparations from purified timothy (Phleum pratense) pollen extracts. II. Anaphylaxis studies in rats and histamine release from human leukocytes. 617 51

A newly synthesized compound, [[3-(1H-tetrazol-5-yl)-phenyl] amino]oxoacetic acid n-butyl ester (MTB) has been demonstrated to be an orally active antiallergic agent. This compound inhibited the 48-hr passive cutaneous anaphylaxis (48-hr PCA) induced by IgE in rats. In guinea pigs, MTB also inhibited the 8-day passive cutaneous anaphylaxis (8-day PCA) and the 8-day passive systemic anaphylaxis induced by IgE. The compound partially inhibited the IgG-mediated 3-hr PCA in rats and guinea pigs, but failed to have any effect on the rabbit IgG-mediated 3-hr PCA in these animals. In the rat, MTB was not an antagonist of histamine or serotonin. The antiallergic effect of MTB was not mediated via any adrenergic mechanisms. MTB significantly inhibited histamine release from rat peritoneal cells induced by rat IgE in vitro.
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PMID:Antiallergic properties of an orally effective agent, [[3-(1H-tetrazol-5-yl)-phenyl] amino] oxoacetic acid n-butyl ester. 618 23


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