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Biomedical subjects

I Søndergaard

Publications and source records attributed to I Søndergaard.

53 records · Page 3Linked to original sources
PubMed1984

Isolation of patient-related antigens from allergen extracts by means of protein A-sepharose-patient IgG1,2,4 bio-affinity chromatography.

A method is described for bio-affinity purification of patient-specific IgG reactive antigens by using protein A-sepharose allergic patient serum and the corresponding antigen/allergen extract. The optimal conditions for each step have been determined and it is shown that the non-specific binding of both serum proteins and antigens can be kept at very low levels by a high ionic strength. The specificity of the reaction has been shown by biospecific elution of 125I-labelled antigens by non-labelled antigens and also by comparison of the amount of antigen bound by sera from hyposensitized patients with that from non-atopic individuals. It is suggested that the isolated antigen-IgG-immune complexes could be used for a specific and active immunotherapy.

Allergens↗
PubMed1984

A three-layer immunoradiometric assay for determination of IgG subclass antibodies in human sera ("IgG subclass RAST"). Validation of the subclass specificity, and establishment of equipotency.

We report the development of a three-layer immunoradiometric assay (TIRA) for measurement of IgG antibodies of all four subclasses in human sera. The first layer consists of diluted human serum, the second layer is monoclonal mouse antibodies to human IgG subclasses, and the third layer is 125I-labelled rabbit anti-mouse IgG. Monoclonal anti-IgG1, anti-IgG3 and anti-IgG4 reacted only with their complementary IgG subclass, whereas the anti-IgG2 showed slight cross-reactivity to immunoglobins of other subclasses and classes and to light chain proteins. The observed cross-reactivity was found to be without importance, when the TIRA was applied to measurement of IgG subclass antibodies. Equipotency was established by use of appropriate dilutions of the monoclonal antibodies, and the assay was calibrated by use of human reference serum. The TIRA therefore permits reliable inter-individual and intra-individual comparisons of the IgG antibody response in all four subclasses. Non-specific binding obtained with pooled normal human serum was below 0.33%. Inter-assay coefficient of variation was between 18 and 27%. The TIRA was applied to measurement of IgG subclass antibodies to timothy grass pollen in sera from grass pollen allergics undergoing immunotherapy.

Animals↗
PubMed1984

A modified crossed radioimmunoelectrophoretic method for determination of allergen-specific IgG antibodies. Elimination of non-specific binding by use of F(ab')2-fragments of rabbit antibodies and 125I-labelled protein A.

A crossed radioimmunoelectrophoretic (CRIE) method for detection of specific IgG antibodies in patients' sera against horse hair and dander was developed. The unacceptably high non-specific binding encountered when substituting 125I-labelled antihuman IgG for 125I-labelled antihuman IgE in an ordinary CRIE was eliminated by the combined use of 125I-labelled Protein A as detector, and F(ab')2-fragments of the allergen-specific rabbit antibodies. The low background binding thus obtained makes the method useful for detection of specific IgG in sera where the ratio between specific and non-specific IgG is low. Therefore the method should also be applicable to other antigen/allergen systems.

Animals↗
PubMed1984

Plasma separation in patients with bronchial asthma, atopic dermatitis and hyperimmunoglobulinaemia E.

The effect of intensive plasma separation performed eight times within 5 weeks in four patients with atopic dermatitis, bronchial asthma and hyperimmunoglobulinaemia E was followed as regards clinical symptoms and changes in the concentrations of serum (S) IgE, S IgG, S IgA, S IgM, plasma complement C3 split products, S transferrin, blood eosinophils, chemotaxis of neutrophil cells and histamine metabolites in urine in samples obtained consecutively during the period of observation. The occurrence of circulating immune complexes (IC) was analysed by a polyclonal rheumatoid factor (pRF) agglutination inhibition assay and an IgE IC specific technique. IgE IC were demonstrated in three of the patients prior to plasma separation, complexed IgE was 2-3% of the total concentration of S IgE. In one patient complexes were detected by the pRF agglutination inhibition assay, also. In the three patients with IgE IC, the complexes disappeared during treatment, but recurred in two of the patients shortly after the last plasma separation. Shortly after eight separations the S IgE was reduced in all patients to a mean level of 46% of the pre-exchange concentrations. During the following 3 weeks the relative increase of S IgE in three of the patients was similar to the values obtained for S IgG. Serum IgG was subnormal in all patients during the period of treatment. Increasing numbers of eosinophils were observed in three of the patients after the fifth separation procedure. The histamine metabolite 1,4-methylimidazoleacetic (1,4- MIAA ) in urine was increased in all patients, but no significant changes were observed during the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Purification of patient-related allergens by means of bioaffinity chromatography on a sepharose anti-IgE patient IgE immunosorbent.

A method is described for bioaffinity chromatographic purification of patient-specific IgE reactive allergens by using sepharose coupled rabbit anti-human IgE antibodies, patient serum and an allergen extract. The conditions for this bioaffinity chromatographic procedure have been optimised, and it was shown that the nonspecific binding of serum proteins and antigens can be kept at very low levels by a high ionic strength. The specificity of the method has been determined by showing that allergens to which the patient did not react were not bound to the affinity matrix. We suggest that the isolated allergens could be used for more specific immunotherapy in the future.

Allergens↗
PubMed1984

Characterization of IgG-subclass antibodies to individual allergens by crossed radioimmunoelectrophoresis.

A crossed radioimmunoelectrophoretic (CRIE) method for detection of human IgG subclass specificities against individual antigens is described. After crossed immunoelectrophoresis (CIE) of the antigens the immunoplates are incubated with serum, washed and incubated with mouse monoclonal anti-human IgG-subclass antibodies. After washing, the plates are finally incubated with the 125I-labelled detector protein, rabbit anti-mouse IgG, and washed. The plates are then placed on an X-ray film for autoradiography. The specificity of the method was tested by inhibition with antigens in the first layer and by inhibition with myeloma sera containing only one IgG subclass protein in the second layer. The specificity of the third layer was assured by affinity purification of the rabbit anti-mouse IgG antibodies. The method was shown to be sensitive and specific. The test systems were timothy (Phleum pratense) pollen antigens and house dust mite (Dermatophagoides pteronyssinus) antigens.

Allergens↗
PubMed1984

Autoimmune type I reactions directed against nuclear components in rheumatoid arthritis.

Basophil histamine release was examined in leucocyte suspensions from patients with rheumatoid arthritis (RA) after challenge of the cells with isolated and sonicated leucocyte nuclei from normal individuals. Most of the patients with active disease responded with significant histamine release, whereas no response was obtained in the inactive patients and in normal controls. A similar pattern was found in the urinary excretion of the main metabolite of histamine, NT-methyl-imidazoleacetic acid, since an increased excretion was observed in most patients with severe disease activity in contrast to patients with moderate and quiescent activity and the control group. These findings strongly indicate an involvement of autoimmune allergic type I reactions in RA. The release of histamine and other mediators from basophils and mast cells may cooperate in the inflammatory reactions and the destruction of the joints in RA.

Adult↗
PubMed1983

A nylon ball solid-phase radioimmunoassay for specific antibodies in human sera. Application to measurement of IgG antibodies to pollen allergens.

The principle of the radioallergosorbent test (RAST) has been used to measure IgG antibodies to timothy grass pollen allergens in sera from desensitized allergic subjects. 125I-labeled goat anti-human IgG was used as detector protein. Non-specific binding was eliminated by use of a non-porous nylon ball an antigen carrier and by use of a special buffer with high ionic strength and pH, containing 1% bovine gamma globulin and 5% normal rabbit serum as 'balance proteins'. At dilution 1:80 non-specific binding was only 0.28% and the binding ratio for a high-liter serum was about 10. By inhibition experiments the assay was demonstrated to be specific for IgG antibodies to timothy grass pollen. The results obtained with this assay correlated statistically significantly with those found th a double -antibody method (rs equal 0.68, n equal 20, t equal 3.93, P less than 0.001). Serum dilution curves were parallel, indicating that the assay is in allergen excess. The within-assay coefficient of variation ranged from 3.9 to 7.6%; the between-assay coefficient of variation from 8.4 to 19.5%. The assay is very simple to perform, requiring no centrifugation. The allergen-coated balls are stable for at least 3 months. The assay should be applicable to measurement of IgG antibodies and IgG subclass antibodies to any protein antigen of interest.

Antibodies↗
PubMed1983

An automated particle counting immunoassay (PACIA) for determination of blocking antibodies against timothy grass pollen in sera from desensitized allergics.

An automated particle counting immunoassay (PACIA) for measurement of blocking antibodies (antigen neutralizing capacity) against timothy grass pollen extract in sera from desensitized allergics is described. Latex particles coated with F(ab')2-anti-timothy are agglutinated by timothy. Serum containing anti-timothy antibodies inhibits the agglutination. Non-agglutinated particles are counted in a modified AutoCounter. Nineteen of 20 sera from timothy allergics who had undergone immunotherapy with purified timothy extract for 30 weeks, showed significant agglutination-inhibition. None of 42 normal human sera gave significant inhibition. The inhibiting antibody could be removed by absorption with protein A and was thus of non-IgE nature, i.e. blocking antibody. The results obtained correlated statistically significantly with those found with a double-antibody method (rS = 0.62, n = 20, t = 3.35, P less than 0.01) and with the cumulated dosage of timothy allergen extract administered to the individual patient (rS = 0.56, n = 20, t = 2.87, P less than 0.02). Between-assay coefficient of variation was from 6.4% to 18.3%. The capacity is 40 samples per hour. The method has also been applied to measurement of blocking antibodies to honey bee and wasp venom.

Animals↗
PubMed1982

Allergen content in aqueous and hydrophobic extracts from cow hair and dander. Comparison of extracts by means of quantitative immunoelectrophoresis.

Rabbit antibodies were raised separately against an aqueous and a detergent extract of cow hair and dander. It is shown by means of quantitative immunoelectrophoresis that the extracts contain the same major allergens and that these are equally potent in RAST-inhibition experiments. The extraction with a detergent did not lead to the appearance of new allergens.

Allergens↗
PubMed1982

Quantitative determination of 1,4-methyl-imidazoleacetic acid in urine by high performance liquid chromatography.

A reversed phase ion-pair high performance liquid chromatographic (HPLC) method for quantitative determination of the major histamine metabolite 1,4-methyl-imidazoleacetic acid (1,4-MIAA) in urine is described. The sample handling is minimal as the sample only has to be centrifuged and diluted before analysis, in contrast to earlier gas chromatographic and thin-layer chromatographic methods. The method correlates well with a thin-layer chromatographic determination (r = 0.79, n = 15), and results from analysis of urine from different patients suffering from mastocytosis, chronic urticaria, atopic dermatitis and asthma are presented together with samples from normal individuals. Most of the patients analysed showed increased excretion of 1,4-MIAA compared with the controls. Future applications of the method, including analysis on patients with food allergy and patients with abnormalities in their histamine metabolism, are discussed.

Arthritis, Rheumatoid↗
PubMed1981

Theophylline concentrations in serum and saliva after oral microcrystalline and sustained-release preparations in asthmatics.

Theophylline concentrations in saliva have been compared with those in serum in 13 asthmatic patients after single and multiple oral dosage of a microcrystalline theophylline tablet (Nuelin) and a sustained-release preparation (Nuelin Retard). There was wide individual variation in the ratio of serum to saliva concentrations indicating that, even when individual serum to saliva ratios have been established, the use of saliva theophylline measurements alone is unreliable for the routine monitoring of theophylline therapy. Both preparations produced mean serum theophylline concentrations within the 10--20 mcg/ml range, the sustained-release tablet giving higher monitoring through values and smaller through to peak variation. The preparations were equally and highly bioavailable. Side effects were reported by three patients, which were the patients with the highest AUC. The Nuelin Retard preparation appears to provide smooth, sustained serum theophylline concentrations within the therapeutic range and the simple, twice-daily dosage should result in improved patient compliance.

Administration, Oral↗
PubMed1979

Inhibition of 5-HT uptake into neurons and platelets in mice treated chronically with chlorimipramine and femoxetine.

A single treatment with 5-HT uptake inhibitors potentiates the hypermotility in mice produced by the MAO-inhibitor nialamide. The effect of nialamide on motility was studied in mice after 4 weeks of feeding with a normal diet and diets containing various concentrations of the 5-HT uptake inhibitors chlorimipramine and femoxetine. Chronic treatment with the two substances enhanced the motor effects of nialamide about equally, which indicates a preservation of the neuronal 5-HT uptake inhibition during such treatment. The effect of chlorimipramine and femoxetine was obtained at plasma levels equivalent to or lower than the steady-state plasma concentrations found in patients treated with two 5-HT uptake inhibitors. Determination of decreased blood 5-HT after the 4 weeks of treatment was used as an in vivo test for inhibition of 5-HT uptake into platelets. Femoxetine was a much weaker depletor of blood 5-HT than chlorimipramine. These results indicate that blockade of neuronal 5-HT uptake is obtained at lower doses of femoxetine than blockade of 5-HT uptake into platelets. In contrast, chlorimipramine presumably inhibits 5-HT uptake into neurons and platelets at about the same dose.

Animals↗