The isolation and compsotion of two phosphoproteins from hen's egg.
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ABSTRACT:
SUBMITTER: Clark RC
PROVIDER: S-EPMC1179223 | biostudies-other | 1970 Jul
REPOSITORIES: biostudies-other
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Project description:BackgroundOver the last few years, studies have shown that the majority of egg allergic children tolerate baked egg (e.g., cake), and that consuming baked egg accelerates the resolution of egg allergy. However, few prospective studies demonstrate the step-wise reintroduction of egg at home after developing baked egg tolerance. Although this could have a positive impact on the children's quality of life and nutrition. Additionally, research supporting the theoretical concept that heating in the presence or absence of wheat causes reduced allergenicity of egg proteins is limited.ObjectiveTo investigate the clinically most favorable duration of gradual egg-tolerance induction in baked egg tolerant children at home, with regard to complete raw egg tolerance.MethodsBaked egg tolerant children above 12 months of age were randomly assigned to a short- or long arm protocol. In the short arm, egg-tolerance induction was studied over 18 months compared to 30 months in the long arm. Children were guided through this protocol involving the step-wise introduction of increasingly allergenic forms of egg starting with baked egg offered as cake, followed by hard-boiled egg, omelet/waffle/pancake, soft-boiled egg, and finally raw egg. We hereby designed this protocol based on the influence of thermal processing in the presence or absence of wheat on egg proteins, as investigated by ELISA, SDS-PAGE, and immunoblotting. At inclusion, children either passed an in-hospital cake challenge or had ovomucoid sIgE ≤1.2 kUA/L, which was considered safe for introduction at home.ResultsGel electrophoresis revealed that the ovalbumin band became weaker with heating, while the ovomucoid band remained stable. In accordance, the IgE-binding to ovalbumin decreased with extensive heating, as opposed to ovomucoid. However, heating in the presence of wheat led to a decreased IgE reactivity to ovomucoid. Of the 78 children in the intention-to-treat group, 39 were randomized to each arm. Fifty-eight children reached the raw egg tolerance endpoint, of which 80% were in the short arm and 69% in the long arm. Within the short arm, the median time to raw egg tolerance was 24 months (95% CI, 21-27 months) compared to 30 months (95% CI, 28-32 months) in the long arm (p = 0.005). No grade IV reactions or cases of eosinophilic esophagitis were observed. The short arm was considered to be non-inferior to the long arm.ConclusionOur gradual short arm protocol appears to be safe and allows clinicians to guide baked egg tolerant children toward raw egg tolerance at home. The allergenicity of the egg proteins was affected by heating temperature and duration, as well as the presence of wheat.
| S-EPMC9234941 | biostudies-literature
Project description:1. A description is given of the isolation of a glycoprotein from hen's-egg white; it has been called ovoglycoprotein. 2. It contains 13.6% of hexose, 13.8% of hexosamine and 3% of sialic acid. 3. Hexose occurs as mannose and galactose in the ratio 2:1, hexosamine as glucosamine and sialic acid as N-acetylneuraminic acid. 4. It has S(20,w) 2.47s and a minimum molecular weight, calculated from the tryptophan content, of 24400. 5. At pH3.9 in acetate buffer, I0.1, which is in the isoelectric region, it is resolved into two components, one of which moves slowly towards the anode while the other moves slowly towards the cathode.
| S-EPMC1207049 | biostudies-other
Project description:1. Hen ovotransferrin was examined by isoelectric fractionation. 2. The major component observed in starch-gel electrophoresis can be isolated from the minor component. 3. When non-saturating amounts of iron are added to ovotransferrin, isoelectric fractionation demonstrates the existence of three molecular species corresponding to the metal-free protein, the one-iron-atom-protein complex and the two-iron-atoms-protein complex. 4. Isoelectric fractionation of human serum labelled with (59)Fe suggests that the transferrin of normal human serum also exists as metal-free protein, the one-iron-atom-protein complex and the two-iron-atoms-protein complex. 5. It is concluded that the binding constants for the first and second iron atoms are similar.
| S-EPMC1198770 | biostudies-other
Project description:Allergen-stimulated T cells from hen’s egg-allergic children were analyzed to identify genes that are specifically up-regulated in these cells. Keywords: disease state analysis
2007-04-18 | GSE7512 | GEO
Project description:Iodine is a trace element required for the production of thyroid hormones, essential for metabolism, growth and brain development, particularly in the first trimester of pregnancy. Milk and lean fish are the main dietary sources of iodine in the Norwegian diet. Thus, the aim of the present study was to provide updated analysed values of iodine concentration in six fish species, 27 selected Norwegian iodine-rich dairy foods and Norwegian hen's eggs. The iodine concentrations in the wild fish species varied between 18 ?g/100 g (Atlantic halibut) and 1,210 ?g/100 g (pollack). The iodine concentration of cow milk varied between 12 and 19 ?g/100 g and the iodine concentration of the eggs varied between 23 and 43 ?g/100 g. The results in this study deviate somewhat from the current iodine concentrations in the Norwegian Food Composition Table. This deviation may have a large impact on the assessment of the iodine intake. Hence, updated knowledge about the variation in iodine level of fish, milk, dairy products and hen's egg are of great importance when estimating the iodine intake in the population. These data will contribute substantially to future estimations of dietary iodine intake and will be made available for the public Norwegian Food Composition Table.
| S-EPMC5971469 | biostudies-literature
Project description:The classical in vitro genotoxicity test battery is known to be sensitive for indicating genotoxicity. However, a high rate of 'misleading positives' was reported when three assays were combined as required by several legislations. Despite the recent optimisations of the standard in vitro tests, two gaps could hardly be addressed with assays based on 2D monolayer cell cultures: the route of exposure and a relevant intrinsic metabolic capacity to transform pro-mutagens into reactive metabolites. Following these considerations, fertilised chicken eggs have been introduced into genotoxicity testing and were combined with a classical read-out parameter, the micronucleus frequency in circulating erythrocytes, to develop the hen's egg test for micronucleus induction (HET-MN). As a major advantage, the test mirrors the systemic availability of compounds after oral exposure by reflecting certain steps of Absorption, Distribution, Metabolism, Excretion (ADME) without being considered as an animal experiment. The assay is supposed to add to a toolbox of assays to follow up on positive findings from initial testing with classical in vitro assays. We here report on a validation exercise, in which >30 chemicals were tested double-blinded in three laboratories. The specificity and sensitivity of the HET-MN were calculated to be 98 and 84%, respectively, corresponding to an overall accuracy of 91%. A detailed protocol, which includes a picture atlas detailing the cell and micronuclei analysis, is published in parallel (Maul et al. Validation of the hen's egg test for micronucleus induction (HET-MN): detailed protocol including scoring atlas, historical control data and statistical analysis).
| S-EPMC9071061 | biostudies-literature
Project description:BackgroundCow's milk (CM) and hen's egg (HE) are leading triggers of anaphylaxis in early childhood. The aim of this study was to identify clinical phenotypes and therapeutic measures for CM anaphylaxis (CMA) compared to HE anaphylaxis (HEA) in children up to 12 years of age, based on a large pan-European dataset from the European Anaphylaxis Registry.MethodsData from 2007 to 2020 on clinical phenotypes and treatment from 10 European countries, as well as Brazil, were analysed. The two-step cluster analysis was used to identify the most frequent phenotypes. For each trigger, three clusters were extracted based on sex, age, and existence of symptoms in four vitally important systems.ResultsAltogether 284 children with CMA and 200 children with HEA were identified. They were characterised as male (69% vs. 64%), infants (65% vs. 61%), with a most frequent grade III of Ring&Messmer classification (62% vs. 64%), in CMA versus HEA, respectively. Respiratory symptoms occurred more often in CMA (91% vs. 83%, p = 0.010), especially in infants (89% vs. 79%, p = 0.008). Cardiovascular symptoms were less frequent in CMA (30% vs. 44%, p = 0.002), in both infants (33% vs. 46%, p = 0.027), and older children (25% vs. 42%, p = 0.021). The clusters extracted in the CMA group were characterised as: (1) mild dermal infants with severe GI (40%), 2. severe dermal (35%), 3. respiratory (25%). While in HEA group: 1. infants with severe GI and/or reduction of alertness (40%), (2) conjunctival (16%), (3) mild GI without conjunctivitis (44%). The severity of the reaction was independent from the amount of ingested allergen protein, regardless of trigger. The first-line adrenaline application differed between the countries (0%-92%, as well as the reasons for not administering adrenaline, p < 0.001).ConclusionsDespite the similarity of their age, sex, and severity grade, the clinical profiles differed between the CMA and HEA children. Adrenaline was underused, and its administration was country dependent. Further studies are needed to assess to what extent the differences in the clinical profiles are related to matrix and/or absorption effects, and/or the allergen itself.
| S-EPMC10040951 | biostudies-literature
Project description:1. We have evaluated several methods for coupling protected tryptic peptides and have selected one that is satisfactory in terms of efficiency and degree of racemization. 2. We report the use of the chosen method (which must be slightly modified for each application in the light of the result of micro-scale pilot experiments) for the preparation of five fragments of hen's-egg lysozyme ranging in length from 31 to 51 residues. 3. We report methods for the complete deprotection of these fragments. They have been characterized by end-group determination, amino acid analysis and tryptic digestion.
| S-EPMC1164145 | biostudies-other
Project description:Hen's egg allergy is the second most common food allergy among infants and young children. The possible presence of undeclared eggs in foods poses a significant risk to sensitized individuals. Therefore, reliable egg allergen detection methods are needed to ensure compliance with food labeling and improve consumer protection. This work describes for the first time the application of phage display technology for the generation of a recombinant antibody aimed at the specific detection of hen's ovomucoid. First, a single-chain variable fragment (scFv) library was constructed from mRNA isolated from the spleen of a rabbit immunized with ovomucoid. After rounds of biopanning, four binding clones were isolated and characterized. Based on the best ovomucoid-binding candidate SR-G1, an indirect phage enzyme-linked immunosorbent assay (phage-ELISA) was developed, reaching limits of detection and quantitation of 43 and 79 ng/mL of ovomucoid, respectively. The developed ELISA was applied to the analysis of a wide variety of food products, obtaining a good correlation with a commercial egg detection assay used as a reference. Finally, in silico modeling of the antigen-antibody complex revealed that the main interactions most likely occur between the scFv heavy chain and the ovomucoid domain-III, the most immunogenic region of this allergen.
| S-EPMC10606182 | biostudies-literature
Project description:We investigated the effects of different types of heat treatments on hen's egg white (HEw) and quail egg white (QEw) proteins and their cross-reactivity in young children. Crude extracts of raw and water-boiled HEw and QEw and commercially developed stone-baked HEw were prepared. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was then performed. Patients diagnosed with HEw allergy were enrolled, and pooled sera were tested with each extract in an enzyme-linked immunosorbent assay (ELISA)-inhibition test. A skin prick test (SPT) and oral food challenge (OFC) were also performed. The median age of 12 patients was 2.5 years. SDS-PAGE results revealed strongly stained bands for the ovomucoid of boiled HEw and QEw, while stone-baked HEw displayed remarkable changes for all protein fractions. In the ELISA-inhibition test, pre-incubation of the sera led to a profound decrease, moderate decrease, and minimal decrease in the amount of IgE binding to boiled and raw HEw, boiled and raw QEw, and stone-baked HEw proteins, respectively. SPTs and OFC demonstrated cross-reactivity values of 41.7% (5/12) and 16.7% (2/12) for boiled QEw and stone-baked HEw, respectively. We observed moderate cross-reactivity between QEw and HEw. Boiling had a limited effect on altering egg allergenicity. Commercially developed, stone-baked HEw can be an alternative food for children with HE allergy.
| S-EPMC8308246 | biostudies-literature