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 heat inactivation at 56 degrees C of mouse IgE antibodies, measured by their PCA activity, was studied in various experimental conditions. Mouse IgE antibodies are partially protected against heat inactivation when previously diluted in sodium chloride or in phosphate buffer media. The protection is better at a higher dilution and molarity (phosphate 1M) and at pH 7. Heat inactivation is increased by the presence of reducing, alkylating and denaturating agents. Heat lability depends upon the concentration of serum proteins in the medium and is increased in presence of immunoglobulins.
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PMID:[Thermolability at 56 degrees C of mouse IgE antibodies]. 84 74

Guinea pigs were sensitized by p-phenetidine (PT), 2-hydroxy-p-phenetidine (HPT) as well as by conjugates prepared by reacting PT and HPT with proteins in vitro. Sensitization was evaluated by delayed skin reactivity and in vitro antigen-induced lymphocyte proleferation. HPT and HPT-protein conjugates were found to be the most effective sensitizing agents. Reaginic antibodies could be raised in both guinea pigs and rabbits by immunizing with PT- and HPT-protein conjugates but not by PT and HPT alone: these PCA antibodies showed strong cross-reactivity and could be elicited equally well with either the PT- or HPT-protein derivatives. By contrast, no precipitating antibodies could be raised in either species even after repeated immunizations over a period of 4 months. Peripheral blood lymphocytes, from a few patients who gave a positive patch test with PT, could be stiumlated in vitro with phenacetin and to a lesser degree with PT and with a HPT-derivative of human serum albumin.
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PMID:Immunogenicity of p-phenetidine, 2-hydroxy-p-phenetidine and their protein conjugates in guinea pigs, rabbits and man. 85 31

[3H]Glutamic acid (PCA) was followed with time after a single subcutaneous injection. PCA specific activity increased slowly, reaching a peak at 3 to 4 days after injection of the labeled amino acid, after which it slowly decline. Incorporation of [3H]glutamic acid into epidermal PCA was markedly inhibited by a single topical application of cycloheximide. Topical application of cycloheximide 2 hr prior to [3H]glutamate injection caused a significantly greater reduction in PCA specific activity (determined 3 days after injection) than cycloheximide treatment 3 hr after administration of the labeled amino acid. Ninety-seven percent of the PCA content of hairless mouse epidermis was shown to reside in the stratum corneum. These observations indicate the involvement of protein synthesis in the formation of PCA from glutamic acid rather than a direct conversion of the amino acid. The high level of PCA in mammalian epidermis appears to be caused by its accumulation in the stratum corneum accompainied by a relatively slow rate of PCA turnover in comparison to other tissues.
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PMID:Biosynthesis of pyrrolidone carboxylic acid in hairless mouse epidermis. 87 May 63

Two new chromone derivatives have been identified which possess oral anti-allergic activity in the rat PCA model of immediate hypersensitivity. They may have a wider spectrum of anti-allergic activity than disodium cromoglycate (SCG) since they are effective in in vitro tests involving sensitized basophils, in which SCG is inactive. Both compounds, when given orally, provide relief from experimental and clinical asthma in man.
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PMID:New orally effective chromosome derivatives for the treatment of asthma. 93 Jul 55

Adipokinetic hormone, isolated from locust corpora cardiaca, has been identified as a blocked peptide: PCA-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2. The detailed structure is based on mass spectrometric data, substantiated in part by dansyl-Edman and carboxypeptidase data on thermolytic fragments. This is the first peptide hormone from an insect neuroendocrine organ to be fully characterised.
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PMID:Structure of locust adipokinetic hormone, a neurohormone that regulates lipid utilisation during flight. 95 72

The heterologous adoptive cutaneous anaphylaxis system was used to determine the kinetics of appearance of IgE-producing cells in various lymphoid tissues of mice following intratracheal (i.t.), intraperitoneal (i.p.), or subcutaneous (s.c.) immunization with tetanus toxoid and Bordetella pertussis organisms. Immunization, i.t. and i.p., produced similar patterns of response with the bronchial lymph nodes quantitatively exceeding the responses in other lymphoid tissues. In both cases the splenic lymphocyte response was second only to the bronchial and both appeared to parallel the serum PCA antibody. It is suggested that both responses represent draining lymph node responses since the bronchial lymph node drains both sites of immunization. After s.c. immunization a primary response of low order was found in the draining popliteal lymph node but not elsewhere. Although a dissociation was seen between responses obtained in various lymphoid tissues following s.c. and i.p. or i.t. immunization, no real evidence for a local mucosal response, such as has been reported for IgA, was obtained. These results lend experimental support to the observations that intratracheal and intraperitoneal immunization routes are most effective in production of IgE antibodies.
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PMID:Kinetics and localization of IgE tetanus antibody response in mice immunized by the intratracheal, intraperitoneal and subcutaneous routes. 99 17

CFW female mice immunized with tobacco leaf extract developed type 1 skin and mast cell sensitivities that could be quantitated. The presence of both IgG1- and IgE-tobacco-mast-cell-sensitizing antibodies was detected by 2 and 48 h. PCA test. On the basis of these findings, it is suggested that mice can surve as good animal models for critical investigation of tobacco hypersensitivity in the laboratory.
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PMID:Evaluation of tobacco hypersensitivity responses in the mouse. A potential animal model for critical study of tobacco allergy. 100 11

When Rhodopseudomonas spheroides cells grown aerobically in the dark were incubated in medium containing tritiated water (THO), incorporation of T into the bacterial cell materials occurred under growth and no-growth conditions. The overall T incorporation under no-growth conditions was stimulated by vigorous aeration and was suppressed strongly in the presence of either 10(-3) M KCN or 0.3% HgCl2, indicating that the bulk of the incorporation might depend upon bacterial cell metabolism or respiration. 10 mug/ml chloramphenicol and 20 mug/ml rifamipicin slightly suppressed the T incorporation. The extent of T incorporation was proportional to the concentration of T in the medium. Accordingly, regardless of differences in the concentration of T in the medium, the maximum ratio of T content per hydrogen atom in the cell materials to that of THO in the medium was approximately 0.2 in non-growing cells and 0.5 in growing cells, whereas the value was 0.02-0.03 in cells incubated in medium containing KCN or HgCl2. The non-growing cells aerated in THO medium were lyophilized and fractionated by the modified method of Schneider. More than 40% of the total T incorporated into the cell materials was recovered in the cold PCA-soluble fraction, whereas the distribution of T into fractions solbule in ether-ethanol, hot PCA and alkali was 10 to 20% each. More than 75% of the T extracted in the cold PCA-soluble fraction was volatile. While the amounts of RNA and protein in the non-growing cells decreased on adding chloramphenicol or rifampicin, the distribution of T in these fractions did not change much. Our results on T incorporation into non-growing cells indicate that the major T incorporation into bacterial cell materials is independent of biosynthetic reactions using labeled precursors produced by the assimilation of T into metabolites, but presumably depends on energy-linked conformational changes of macromolecules.
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PMID:Incorporation of tritium into cell materials of Rhodopseudomonas spheroides from tritiated water in the medium under aerobic conditions. 108 4

Chromatographically separated antigens of Mycobacterium leprae were tested for their ability to elicit skin reactions in guinea-pigs sensitised with homologous and heterologous mycobacteria. Of the three antigen-positive fractions obtained, one showed specific activity and the other two cross-reactivity, as indicated by studies of hypersensitivity and passive cutaneous anaphylaxis. The fraction exhibiting specificity contained only one antigen, which was protein in nature, whereas the other two fractions contained more than one antigen and possessed both protein and polysaccharide constituents. Because the single-antigen-containing fraction showed both positive skin and PCA reactivity, the suggestion is made that this fraction may contain either an antigen with two determinants or may contain two antigens that are not easily distinguishable by immunodiffusion methods.
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PMID:Immunological studies on leprosy: separation and evaluation of the antigens of Mycobacterium leprae. 109 49

Mouse IgE was titrated in rats. The sensitization period was 2 h. The results were consistent and corresponded to the titers obtained in young adults SJL mice using a sensitization period of 48 h. With longer sensitization periods in rats, higher antibody titers were obtained. The optimum sensitization period in rats was found to be 48 h. Old CFW mice are inadequate for mouse IgE titration. IgG1 will not give a PCA reaction in rats. IgG1 titers are higher in SJL or A/J mice than in young CFW mice, and markedly higher than in old CFW mice.
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PMID:PCA reactions with mouse antibodies in mice and rats. 111 78


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