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Biomedical subjects

K Aas

Publications and source records attributed to K Aas.

At least 55 records · Page 3Linked to original sources
PubMed1978

The diagnosis of immediate type allergy to Cladosporium herbarum. Differences between extracts and the efficacy of radioallergosorbent test (RAST) assays.

The radioallergosorbent test (RAST) was used to demonstrate IgE antibodies to Cladosporium herbarum in 35 children. Freeze-dried samples of Cladosporium herbarum were obtained from two commercial products, extracted and used for the preparation of two rast disc series which were compared with the commercially available Phadebas Cladosporium herbarum discs. Marked qualitative differences were found.

Child↗
PubMed1978

Demonstration of distinct allergens by means of immunological methods. Comparison of crossed radioimmunoelectrophoresis, radioallergosorbent test and in vivo passive transfer test.

An immunosorbent column was prepared containing a purified major allergen fraction from codfish (DS 22) covalently coupled to agarose. Sera from patients allergic to codfish were run through the column at pH 7.2. After extensive washing, the IgE retarded in the column was eluted with a buffer at pH2.5. The original sera and fractions from the chromatography experiments were examined by means of crossed immunoelectrophoresis (CIE), crossed radioimmunoelectrophoresis (CRIE), radioallergosorbent test (RAST) and in vivo passive transfer (PK) tests using the DS 22 from codfish and a crude codfish extract. The experiments demonstrated that the crude extract contained a minor codfish allergen (antigen-17-cod) which was distinct from DS 22. RAST was the most convenient technique for the identification of fractions containing allergenic activity. The PK tests served to prove the biological activity in vivo. CIE/CRIE were superior to RAST and PK tests regarding their ability to identify distinct allergens. Full agreement was found between results using different techniques including the immunosorbent experiments. Some of the radiostaining in CRIE, however, was misleading due to coprecipitation of DS 22 in several precipitates in the CIE preparations of the crude codfish extract.

Allergens↗
PubMed1978

Crossed immunoelectrophoretic and crossed radioimmunoelectrophoretic studies employing a model allergen from codfish.

A standard reference pattern in crossed immunoelectrophoresis (CIE) of the parvalbumin fraction of a cod white muscle extract was established. Crossed line immunoelectrophoresis (CLIE), tandem CIE and crossed radioimmunoelectrophoresis (CRIE) were used to identify the major allergens, thereby establishing a basis for future work employing quantitative immunoelectrophoretic techniques in the study of codfish allergens. Rocket immunoelectrophoresis and rocket-line immunoelectrophoresis were used to demonstrate antigenic determinants on polypeptide fragments of the major allergen, Allergen M. The results show the usefulness of these techniques in studies of antigenic determinants on non-precipitating polypeptides. CRIE with 8 patients's sera showed radiostaining indicating IgE binding corresponding to at least 7 precipitates in the crude extract CIE preparations. The purified DS 22 fraction was shown to contain 2 CRIE-positive (IgE-binding) precipitates. When using Allergen M, these precipitates were also demonstrated, one of them in trace amounts only.

Allergens↗
PubMed1978

In vitro sensitization and mast cell degranulation in human jejunal mucosa.

Sera from 3 allergic patients with specific IgE antibodies as shown by RAST were used to sensitize jejunal mucosa obtained from surgical patients. The sensitized specimens were challenged with the appropriate antigens to the specific IgE shown in the sera, Non-challenged sensitized specimens were used as controls to determine mast cell degranulation. The mast cells were counted in a defined area in the mucosa immediately adjacent to the muscularis mucosa. Mast cell degranulation was 47 percent in a timothy pollen system, 40 percent in an eggwhite system, and 33 percent in a codfish system. The results of the investigation indicates that mast cells in the human jejunal mucosa are able to react in the same manner as mast cells in the human lung. The experimental model described appears suitable for studying the allergic reaction in the gastrointestinal tract and the effect of pharmacotherapy in this respect.

Antibodies↗
PubMed1977

A reference system in crossed radioimmunoelectrophoresis.

A reference system for crossed radioimmunoelectrophoresis (CRIE) has been developed. The system takes into account the variable quality of the 125I-labeled anti-IgE and permits a direct comparison of the results from one experiment to another. Simultaneously with the preparation of the CRIE slides, a standard series of small paper discs are prepared containing varying, defined amounts of 125I-labeled anti-IgE. These paper discs are laid out for autoradiography together with the CRIE slides. After short periods of exposure, only paper discs with large amounts of isotope are visible on the X-ray films. Longer exposure times permit paper discs with smaller amounts of isotope to be visible. Each precipitate is assigned to a Crie class depending on the number of paper discs visible when the precipitate is detected for the first time.

Antigens↗
PubMed1977

A new well-characterized, purified allergen preparation from timothy pollen. I. Chemical properties.

A purified allergen preparation, Timothy N, from timothy pollen (Phleum pratense) was characterized with respect to chemical properties in comparison with a commercially available crude extract, Timothy O, from the same pollen material. In Timothy N about 94% of the protein and 99% of both hexoses and pentoses were removed during the purification. Timothy N contains a limited number of proteins with molecular weights of about 15,000 and 30,000. A Timothy N solution of 0.010 mg/ml will have an allergenic activity of 1 HEP.

Allergens↗
PubMed1977

A new well-characterized, purified allergen preparation from timothy pollen. II. Allergenic in vivo and vitro properties.

A purified allergen preparation, Timothy N, from timothy pollen and a crude commercial extract, Timothy O, prepared from the same pollen material, were tested in tenfold dilutions on 59 adults with allergic rhinitis and on 29 children with bronchial asthma. All patients were allergic to grass pollen. Using the prick and intracutaneous methods, dose-response tablets were established for the two preparations showing a good correlation. Nasal provocation tests on the adult patients and bronchial provocation tests on the children gave positive reactions in all cases when using Timothy N. No irritant effect resulting in non specific reactions were elicited. The availability of stable, freeze-dried and purified allergen preparations supplied in different vials with defined allergenic activities fulfils the clinical demands for a modern diagnostic allergen preparation.

Adolescent↗
PubMed1977

A new well-characterized, purified allergen preparation from timothy pollen. III. Immunological properties in the human immunoglobulin E system.

The following methods were used in vitro to characterize and quantitate the allergenic activity of a purified allergen preparation, Timothy N, from timothy pollen: radioallergosorbent test (RAST), direct-titration RAST and RAST inhibition. Vials containing freeze-dried and standardized quantities of this preparation showed good uniformity and accuracy with regard to the allergenic activity. The stability of the preparation in solution and in the freeze-dried state was tested by RAST inhibition and was found to be acceptable. Using the same method, the allergenic activity of Timothy N was compared to the allergenic activity of a crude extract, Timothy O, indicating a discrepancy which was not observed in vivo.

Allergens↗