Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antigencity of CS-1170, a newly developed semi-synthetic cephamycin, and it's cross-reactivity with beta-lactam antibiotics were studied. The antigencity was confirmed by the following tests: 1)the passive hemagglutination test with anti-CS-1170 antisera of guinea pigs immunized with CS-1170 plus Freund complete adjuvant, 2)lymphocyte proliferation response in vitro stimulated with this drug in the guinea pigs, 3) the PCA test using mice immunized with CS-1170-protein conjugates. The antibody to CS-1170 appears to be directed to the acyl side chain because cyanomethylthioacetylglycine, an univalent acyl side chain of the CS-1170, can significantly cross-react with the antibody. A methoxy group on the C-7 alpha-position of the antibiotic plays no important part for the antigenic specificity of the molecule. The cross-reactivity of CS-1170 with cefazolin, cephalothin, benzylpenicillin and ampicillin was only to a minimal extent in the passive hemagglutination test. The cross-reactivity of CS-1170 and the related antibiotics was not observed among them in the PCA system with IgE anti-CS-1170. These findings support a conclusion that CS-1170 is one of beta-lactam antibiotic with an immunologically minimal cross-reactivity to the related antibiotics.
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PMID:Immunological studies on CS-1170, a new semisynthetic cephamycin antibiotic. 8 34

The strain-dependent variation in susceptibility to passive sensitization of the skin and peritoneal mast cells with homologous IgE antibodies was observed in inbred strains of mice. Strain 129 showed low susceptibility to passive sensitization and high efficiency of normal serum in blocking mouse reagin-induced PCA in rats. Balb/c and C3H/A strains showed higher susceptibility to passive sensitization and the efficiency of normal serum in blocking rat PCA lower than strain 129. The serum factor responsible for rat PCA inhibiting effect was heat-labile. The anaphylactic response of peritoneal mast cells of inbred strains to the challenge with anti-mouse IgE and anti-rat IgE in vitro was low in Balb/c mice, as compared with the response of C57BL/6J and 129 mice. The results suggest, that non-specific IgE present in the serum or bound to the mast cells may be one of the factors determining the susceptibility of mouse strains to reagin-induced passive sensitization. However, the results obtained with C57BL/6J strain suggest the existence of other factors effecting this susceptibility.
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PMID:Passive sensitization of mice and rats with IgE antibodies. 8 39

A series of substituted 11-oxo-11H-pyrido[2,1-b]quinazoline-8-carboxylic acids were prepared and evaluated as antiallergy agents. Several analogues were orally active. 2-Methyl-11-oxo-11H-pyrido[2,1-b]quinoazoline-8-carboxylic acid (6) was superior to cromolyn sodium and doxantrazole orally and intravenously in the rat PCA test and a rat allergic bronchospasm model.
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PMID:Antiallergy activity of substituted 11-oxo-11 H-pyrido[2,1-b]quinazoline-8-carboxylic acids. 8 23

BL-5255, 2-(2-n-propoxyphenyl)-5-(5-1 H-tetrazolyl)pyrimidin-4 (3H)-one, effectively inhibited allergic reactions in sensitized rats or guinea pigs when administered by oral or intravenous routes as the water-soluble sodium or ethanolamine monohydrate salts. In the IgE-mediated rat PCA, BL-5255 was 50 times more potent than disodium cromoglycate by intravenous administration. When administered orally in this model, BL-5255 inhibited the PCA reaction by 50% at 0.1 mg/kg. At less than 0.1 mg/kg p.o., the compound protected conscious actively sensitized guinea pigs from aerosolized antigen-induced collapse. In N. brasiliensis-sensitized rats, BL-5255 administered at 0.1--10 mg/kg p.o. inhibited antigen-induced airway constriction in a dose-related manner. BL-5255 is not a histamine or serotonin antagonist but appears to exert its antiallergic effect by inhibiting the release of mediators.
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PMID:BL-5255, a tetrazolylpyrimidinone with potent oral antiallergy activity in animals. 9 59

Effect of dialysate from buckwheat extract on immediate hypersensitivity reactions. To investigate the hypersensitivity reaction of buckwheat, the aqueous extract of buckwheat was separated into dialysate (BWD) and non-dialysate (BWND). BWD neither decreased a release of anaphylactic mediator from the chopped lung tissue nor inhibited Schultz-dale reaction in the ileum of guinea pig sensitized with BWND. Heterologous PCA mediated by rabbit anti-BWND serum in guinea pig and homologous PCA in rats using anti-BWND IgE serum were inhibited by i.d. or i.v. treatment of BWD. Radioallegosorbent test (RAST) and PK reaction were inhibited in a dose dependent fashion by BWD mixed with human serum sensitive to buckwheat, although BWD required approximately 10,000 times more than BWND to produce a RAST inhibition. RAST, however, was not affected when BWD was added to 125I-labelled anti-human IgE. Anti-buckwheat IgE antibody in sensitized animals and atopic patients was specifically absorbed with an insoluble copolymer of BWD-conjugated BSA. BWD did not form a precipitin line against anti-BWND IgG antibody in immunoelectrophoresis. Rat IgE serum-induced degranulation and histamine release from mast cells were inhibited in a dose dependent fashion by BWD and the inhibition was specific to anti-BWND IgE antibody. BWD may be useful as an hyposensitization agent in buckwheat hypersensitivity, since BWD is a haptenic substance capable of neutralizing specific IgE antibody on mast cells.
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PMID:[Immunopharmacological study of buckwheat hypersensitivity (author's transl)]. 9 95

Orally administered iodoxamide ethyl (U-42,718) inhibited anaphylactic reactions in a dose-related manner in the following test animals: (1) in the rat PCA reaction, excellent activity (75% inhibition at 0.1 mg/kg) was seen with a duration of activity of 30 min, (2) In the ascaris-sensitive primate (45% inhibition at 1.0 mg/kg) in lung parameters related to increased resistance and decreased compliance which persisted for up to 3 h, and (3) 50 mg/kg protected guinea pigs, sensitized to egg albumin, from lung function changes. Activity in these animal systems indicates that this orally active drug may hold promise in clinical asthma.
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PMID:The effect of lodoxamide ethyl [diethyl N,N'-(2-chloro-5-cyano-m-phenylene)dioxamate] on in vivo anaphylactic reactions. 11 53

The sera of atopic and non-atopic persons with allergic pulmonary disorders were examined for long-term sensitizing, IgE and short-term sensitizing heat-stable (S-TS) antibodies which were present separately or together in the sera of some patients sensitive to antigens such as budgerigar serum proteins and Aspergillus funigatus. In fourteen atopic patients with extrinsic asthma, six had both types of antibody to common allergens, and of nine non-atopic patients with crytogenic (intrinsic) asthma, four had only heat-stable short-term sensitizing antibodies. The sera of atopic subjects with type I prick test reactions and positive RAST's, showed specific IgE antibody by baboon PCA tests to budgerigar serum proteins, A. funigatus, Timothy grass pollen extract and hen egg extract, and not to Dermatophagoides farinae, possibly because of naturally occurring mite antibodies in the baboon. The sera of non-atopic asthmatics, who had given negative prick test but positive immediate, dual or late intracutaneous tests, and only late asthmatic reactions, contained precipitins in most cases and gave little or no RAST reaction. On baboon PCA these sera contained either, S-TS antibody alone, or S-TS plus long-term sensitizing antibody, or long-term sensitizing antibody alone. Some of the sera with long-term sensitizing antibody contained blocking antibody which could diffuse away in the 24 hr delay for the baboon PCA test and could also be responsible for the negative RAST. Tests with insoluble anti-IgE immuno-adsorbents on two sera from persons sensitive to aspergillus confirmed that the S-TS activity was not due to IgE, and on two sera with negative RAST and negative prick tests to budgerigar serum antigens confirmed that the 24 hr monkey PCA responses were due to IgE.
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PMID:Clinical correlations between long-term (IgE) and short-term (IgG S-TS) anaphylactic antibodies in atopic and 'non-atopic' subjects with respiratory allergic disease. 11 51

Collagen-anticollagen immune complexes were prepared by gel filtration. Complex formation was chemically and serologically demonstrated. Complexes eluting in gammaM- and gammaG-peaks of antigen-antiserum mixture showed strong positive reactions in PCA experiments performed with 20 guinea pigs. Control preparations of gammaM- and gammaG-peaks of antiserum devoid of antigen gave significantly lower PCA-response. The positive reaction of control preparations can be explained in part by a certain degree of cross-reactivity of anticollagen-antibodies with guinea pig collagen.
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PMID:Biologic activity of soluble collagen-anticollagen immune complexes as demonstrated by passive cutaneous anaphylaxis. 12 69

The results of our recent investigations have suggested that tolerance and cross-tolerance development to motor-impairing and hypothermic effects of ethanol was slowed when brain serotonin (5-HT) was extensively depleted by treatment with p-chlorophenylalanine (p-CPA). These findings have been extended by the observation that p-PCA also slowed the development of tolerance to motor-impairing effects of barbital whether tolerance was tested repeatedly in the same animal or in separate subgroups being tested only once. Additional support was provided by the demonstration that intracerebral injection of 5,7-dihydroxytryptamine (-DHT), which is known to deplete 5-HT markedly, also slowed the development of tolerance to motor-impairing and hypothermic effects of ethanol. In addition, when brain 5-HT level was elevated by administration of L-tryptophan, the rate of tolerance development to ethanol, as measured by motor impairment and hypothermia, was accelerated. In contrast to 5,7-DHT, intracerebral injection of 5,6-DHT was surprisingly found to accelerate the development of tolerance to ethanol. Upon further investigation, however, it was determined that the 5,6-DHT treatment depleted brain 5-HT levels by only 20% and, in addition, resulted in the development of supersensitivity. These results further confirm and extend the generality of our observations that 5-HT may be involved in the development of tolerance and cross-tolerance to sedatives. The possibility of a non-specific vs. specific effect of the serotoninergic system (as well as other aminergic systems) in tolerance and neuroplasticity deserves further investigation. The possible significance of these findings and the role of 5-HT (and noradrenaline) in the mechanism of tolerance are discussed in terms of analogy to enzyme or receptor mechanism.
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PMID:Role of serotonin in tolerance to ethanol and barbiturates: evidence for a specific vs. non-specific concept of tolerance. 16 Aug 66

Tadpole collagenase (EC 3.4.24.3) cleaved chick cranial bone procollagen into two triple-stranded fragments, PCA and PCB. Only PCB, with an estimated molecular weight of about 60,000 for each component chain after reduction, was found to contain interchain disulfide bonds. The analogous cleavage of collagen is known to produce a large NH2-terminal fragment with a molecular weight of 70,000 for each chain and a small COOH-terminal fragment containing chains of about 25,000 molecular weight. Since PCB was too small to represent the product NH2-terminal to the site of collagenase cleavage, localization of interchain disulfide bonds to a COOH-terminal domain in procollagen was indicated. This assignment was conformed by Dintzis-type short-term labeling experiments. Procollagen obtained by acid extraction of bone lacked the COOH-terminal disulfide-bonded domain. The findings support a model for procollagen consisting of three proalpha chains each containing nonhelical NH2-terminal extensions of 20,000 molecular weight and COOH-terminal extensions of about 35,000 molecular weight, the latter linked by interchani disulfide bonds.
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PMID:Interchain disulfide bonds in procollagen are located in a large nontriple-helical COOH-terminal domain. 17 50


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