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Biomedical subjects

K Aas

Publications and source records attributed to K Aas.

At least 19 recordsLinked to original sources
PubMed1992

Experimental colonic inflammation and ulceration. Permeation of a water-soluble contrast medium as a measure of 'disease' activity.

The aim of this study was to investigate the permeation of an isosmolar water-soluble X-ray contrast medium (CM) from the unperforated colon after experimental induction of inflammation and ulceration. One hundred and sixty-five male rats were included. In 110 rats 0.25 ml of 40% ethanol + 15 mg or 30 mg trinitrobenzene (TNB) was instilled into the colon, 7-9 cm proximal to the anus, inducing different degrees of inflammation. Fifty-five rats served as controls and had 0.25 ml saline instilled with the same procedure. At 7, 14, 21, and 28 days 3 ml of the non-ionic CM iodixanol was applied as an enema, and subsequently all urine was collected for the next 4 h. High-performance liquid chromatography analyses of the urine showed a positive relation between the severity of inflammation/ulceration in the colonic wall as assessed by a macroscopic damage score and the amount of CM excreted in the urine. Water-soluble contrast media may have prospects of combining functional tests of intestinal membrane dysfunction with segmental exposure control.

Animals↗
PubMed1979

Effects of ketotifen and clemastine on passive transfer of reaginic reaction.

Passive transfer (PK) tests were performed with a reaginic serum on a recipient reacting with an immediate and a more prolonged reaction when specificity challenged. Both reactions are thought to be mediated by IgE immunology. Ketotifen, a cycloheptathiophene derivative, and clemastine, given to the recipient in maximal clinical doses for 3 days, inhibited the immediate reaction. Ketotifen had a very slight effect also on the prolonged reaction. The results indicate that the in vivo effects of ketotifen in the human system are due not so much to mast cell inhibitory mechanisms, but more to post-release antihistaminic and some anti-inflammatory properties.

Clemastine↗
PubMed1979

Serum concentrations of theophylline in children following the administration of doses generally recommended: new dosage regimen required.

Serum concentrations of theophylline following intravenous and oral administration of aminophylline were studied in asthmatic children, 2--17 years of age. The biological half-life (t 1/2 beta) of theophylline varied between 165 and 495 min. The results revealed that an intravenous loading dose of 6 mg of aminophylline per kg body weight was necessary in order to obtain therapeutic concentrations in children who had not received the drug for the last 6 to 8 hours. The maintenance dose should be determined and controlled by use of serum concentration determinations. In a group of children receiving 5 mg of aminophylline per kg body weight 3 times a day orally, none had concentrations within the therapeutic range in the morning, and only 39% reached therapeutic levels 2 h after the morning dose. No correlation was found between the serum concentration of theophylline and the amount of drug given per kg body weight. The results show that theophylline concentration analysis is necessary to obtain adequate therapeutic levels in children without risking toxic effects.

Administration, Oral↗
PubMed1978

The diagnosis of hypersensitivity to ingested foods. Reliability of skin prick testing and the radioallergosorbent test with different materials.

The diagnostic reliability in food allergy of skin prick tests (SPT) and the radio-allergosorbent test (RAST) was investigated in paediatric patients with respiratory and skin allergies. SPT and RAST were found to be reliable for the diagnosis of allergy to codfish, peas, nuts, peanuts and egg white. Positive SPT and RAST to cereals were common, but were most often without clinical significance or were correlated with respiratory allergy to the inhalation of flour dust. SPT and RAST were only partly reliable with regard to allergy to cow's milk, and were mostly reliable when used together and showing corresponding results. Experimental allergosorbents for RAST with soy beans and white beans were not reliable. The study shows the need to improve the diagnostic materials and to establish the diagnostic reliability of the material and tests used for each food item in question.

Adolescent↗
PubMed1978

The specificity of radiostaining in crossed radioimmunoelectrophoresis.

The major allergen from codfish (DS 22) was used to study specific and non-specific radiostaining in crossed radioimmunoelectrophoresis (CRIE). Various modifications of CRIE experiments were performed including experiments where immunoprecipitates in agarose were transferred to test tubes and the radioactivity was measured in a gammacounter. The degree of non-specific binding of IgE and 125 I-anti-IgE to the percipitates was low. A linear relation was found between the amount of human serum IgE antibody used in CRIE and the degree of radiostaining obtained. Increasing the amount of DS 22 in the precipitates from 0.31 to 2.5 microgram resulted in a moderate increase in the uptake of 125 I-anti-IgE, whereas further increase of the amount of DS 22 (5--10 microgram) resulted in reduced uptake of isotope. Serum from a patient containing IgE antibodies to rabbit serum gave rise to radiostaining over the entire antibody-containing gel area, and it is suggested that such human sera be avoided when using CRIE.

Allergens↗
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↗