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

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

Several in vivo and in vitro methods for monitoring immunological properties of two allergoids obtained by formaldehyde treatment of ovalbumin (OA) were developed. The calculated molecular weight of allergoids was 80 kD (OA-F1) and 165 kD (OA-F2), respectively. The allergenic activity in vitro of allergoids in mast-cell histamine release assay was 1000 times lower than of OA. Both allergoids showed reduced ability to induce passive cutaneous anaphylaxis in the Sprague-Dawley rats or systemic anaphylaxis in Dunkin-Harley guinea-pigs. The ability of OA and allergoids to bind to the OA-specific IgE antibodies was measured in vivo by the inhibition of passive cutaneous anaphylaxis (PCA-inhibition). Allergoid binding to IgE was 51-66% lower than the native allergen. Moreover, the avidity of OA-specific IgG antibodies, measured by ELISA-inhibition, for allergoids and allergen was of the same order. Allergoids induced a different pattern of humoral immune response from that, induced by the native allergen. Thus, after immunization of BALB/c mouse, both allergoids induced a higher production of IgG and a lower production of IgE than OA, only OA-F2 induced a lower production of IgG1. The differences in the IgA response to the immunogens was not significant. Delayed hypersensitivity studies in the BALB/c mouse showed that allergoids were 5- to 12-times less effective in inducing a cell-mediated immune response than OA. The present study provides a battery of immunological methods for preclinical testing of modified allergens.
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PMID:Characterization of allergoids from ovalbumin in vitro and in vivo. 906 78

Intraepithelial enteroendocrine cells (IEC) produce peptides which influence motility, secretion and absorption of nutrients. Recently the role of these cells in the immune mucosal system is under study. The aim of the present study was to evaluate the modifications in number of IEC in cecum and appendix from Ovalbumin (OVA) sensitized rabbits. Twenty adult New Zealand rabbits were separated in two groups: Group 1 (G1 = 10) not sensitized normal control. Group 2 (G2 = 10) were sensitized twice intraperitoneally with 70 mg OVA and 30 mg ALUM/ml (aluminium hydroxide). Anti OVA specific IgE was evaluated by means of PCA test (passive cutaneous anaphylaxis). Samples form cecum and appendix were fixed in buffered formaldehyde 10%, paraffin embedded and stained with anti-Chromogranin A for neuroendocrine cells. 400 high power fields were counted in each animal, referred as IEC/100 enterocytes. In cecum surface epithelium and crypt were considered. Surface epithelium, deep crypts and superficial crypts were evaluated in appendix. Results showed in cecum in G1:1,6 IEC/100 enterocytes in surface epithelium and 3/100 in crypts; G2 6 IEC/100 in surface epithelium and 12/100 in crypts. The difference between G1 and G2 was statistically significant (p < 0.05). In appendix surface epithelium from G1 showed 5.2/100 while G2 5.4/100. Superficial crypts 8.5 (G1) and 11.3 (G2) (p < 0.05) and deep crypts 4.9 (G1) and 8.5 (G2) (p < 0.01). The results showed that OVA-sensitized animals presented increment in the number of IEC in surface epithelium and crypts which may indicate a relationship between these cells and rabbit mucosal immune system.
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PMID:[Intraepithelial enteroendocrine cells in cecum and appendix from ovoalbumin sensitized rabbits]. 1066 67

Thirty two VOCs including alkanes, aromatic hydrocarbons, terpenes and carbonyl compounds together with NO2 were investigated in a kindergarten classroom, a primary classroom and the playground in 18 schools located in rural areas, an urban area (Ciudad Real) and an industrial area (Puertollano) in the province of Ciudad Real in central southern Spain. The most abundant pollutants at schools were the aldehydes formaldehyde and hexanal. After carbonyls, n-dodecane was the most abundant compound in the study areas. The NO2 concentrations were higher in the urban area, followed by industrial area and rural areas. For benzene, its concentration in the industrial area was significantly higher than in the urban and rural areas which reflects the magnitude of the contribution to the indoor air by petrochemical plant during the sampling period. Principal component analysis, indoor/outdoor ratios, multiple linear regressions and Spearman correlation coefficients were used to investigate the origin, the indoor pollutant determinants and to establish common sources between VOCs and NO2. Seven components were extracted from the application of PCA to the indoor measurements accounting for 77.5% of the total variance. The analysis of indoor/outdoor ratios and correlations demonstrated that sources in the indoor environment are prevailing for most of the investigated VOCs. Benzene and n-pentane have a major relevance as outdoor sources, while aldehydes, terpenes, alkanes and most aromatic hydrocarbons as indoor sources. For NO2, ethylbenzene and toluene both indoor and outdoor sources probably contributed to the measured concentrations. Finally, the results reported in this paper demonstrate that during the measuring period there were not great differences in the indoor air quality of the schools of the three study areas.
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PMID:Indoor and outdoor air concentrations of volatile organic compounds and NO2 in schools of urban, industrial and rural areas in Central-Southern Spain. 2921 55