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X Baur

Publications and source records attributed to X Baur.

At least 217 records · Page 12Linked to original sources
PubMed1991

Isocyanate-induced asthma: results of inhalation tests with TDI, MDI and methacholine.

We performed diisocyanate inhalation tests (maximal concentration, 20 ppb; exposure time, 1-2 h) using toluene diisocyanate (TDI, n = 15) and diphenylmethane diisocyanate (MDI, n = 7) as well as methacholine challenges in 19 workers who had a clinical history of TDI/MDI-induced asthma. Additionally we tested volunteers who had no previous contact with diisocyanates: 10 healthy individuals with a negative methacholine test and 14 patients with asthma and a positive methacholine test were exposed to TDI. In all, 1 of the normal volunteers and 3 of the patients with asthma unrelated to diisocyanates showed a positive airway reaction to TDI, and 13 of the 19 diisocyanate workers displayed a positive result in the TDI/MDI inhalation test; however, only 6 of these 13 individuals reacted to methacholine. Furthermore, 3 of the 6 patients with a negative TDI/MDI challenge test demonstrated a significant response to methacholine. We conclude that bronchial hyperreactivity as evaluated by the methacholine challenge test is not closely related to isocyanate-induced bronchoconstriction and, therefore, the metacholine challenge is only of limited diagnostic value in patients with suspected isocyanate-induced asthma.

Asthma↗
PubMed1991

Isocyanates.

Explore the source record for details and available documents.

Allergens↗
PubMed1991

Immunological cross-reactivity of hemoglobins in the Diptera family Chironomidae.

Polyclonal human IgE antibodies of patients sensitized to one species of the Diptera family Chironomidae as well as polyclonal rabbit anti-Chi t I hyperimmune serum recognize antigenic sites present in nearly all of the 33 species of this insect family. Evolutionary distantly related genera usually show weaker antibody binding. According to the pattern of reactivity of rabbit anti-Chi t I-component III, expression of the epitopes of this molecule varies considerably in the genera Chironomus and Glyptotendipes; it appears to be almost totally absent in all other species. Of five monoclonal antibodies raised against Chi t I-component III, two recognize an epitope which is expressed in nearly all closely related species. Three monoclonal antibodies recognize epitopes which are expressed in only a few species of the same genus. Our results demonstrate the presence of common as well as species-specific epitopes in chironomid hemoglobins which behave as potent inhalant allergens.

Animals↗
PubMed1991

Stimulation of human peripheral blood lymphocytes with chironomid hemoglobin allergen (Chi t I).

Hemoglobins (Chi t I) of the dipteron species Chironomus thummi thummi are known to cause severe allergic diseases in humans. We tested the allergen-specific stimulation of human peripheral blood lymphocytes (PBL) by Chi t I and its nine main components. Further, we applied fragments of the well-analyzed component III, obtained by cleavage with trypsin as well as arginine protease. In this way, we screened the molecule in order to identify T-cell epitopes. The whole component was found to be immunogenic and to have regions demonstrating varying PBL stimulation. In addition, interindividual patterns of reactivity, probably due to genetic restriction, were found. A T-cell epitope could be shown to be within the site 98-111, as predicted by application of Rothbard's algorithms.

Allergens↗
PubMed1991

[Diagnosis of humidifier lung--comparison of various serologic procedures].

Humidifier lung is a form of exogenous-allergic alveolitis caused by microbial growth in humidifiers and air conditioners. It was the aim of the present study to employ and test the ELISA method as an alternative to antibody determination. 134 employees in a large printhouse equipped with air conditioning plant were examined by us. Specific IgG antibodies against contaminated humidifier fluid were determined by means of a solid-phase radioimmunoassay (protein A RAST) that we had developed further. Alternatively we examined a commercially available ELISA method (Pharmacia IgG-RAST 40; enzyme: beta-galactosidase) and an assay based on protein A peroxidase. The influence of different test conditions was studied. All the methods examined proved suitable for determining the specific IgG antibodies. The commercial beta-galactosidase assay could be adapted to application on microtitre plates in a slightly modified form. In the peroxidase assay it is recommended to use very low serum and enzyme concentrations on account of its high sensitivity. Examination of all the 134 serum samples yielded a high correlation between the results of these two non-radioactive methods and those obtained with the protein-A RAST.

Air Microbiology↗
PubMed1991

[Pearl oyster dust as the cause of exogenous allergic alveolitis].

Many different inhalative substances may cause allergic alveolitis (hypersensitivity pneumonitis). We report on a worker who developed lung fibrosis due to the sensitization to pearl oyster shell dust. High concentrations of IgG antibodies to proteins (conchagens) of the shell which appear to represent the relevant antigens were found in the patient's serum.

Aged↗
PubMed1991

[Correlation of parameters of the flow-volume curve for the assessment of bronchial hyperreactivity].

The association of maximal expiratory flow-volume curve and the response of nonspecific bronchial responsiveness was studied in 265 normal and asthmatic subjects. Bronchial hyperresponsiveness to acetylcholine was found in 143 subjects. These hyperreactive persons had already significantly reduced maximal expiratory flow rate at 75%, 50% and 25% vital capacity before the test started. Besides, we found a significant correlation between the provocative dose and the flow-volume parameters, although resistance was in the normal range. We concluded that the flow rates at middle and low lung volumes may be an important determinant of bronchial sensitivity to acetylcholine.

Acetylcholine↗
PubMed1991

Evaluation of the Radio-Allergo-Sorbent-Test (RAST) with respect to misinterpretations of the results.

Two hundred and twenty two single allergens were assayed in 36 outpatients, using a commercial RAST kit. It was found that a significant proportion of the patients were evaluated incorrectly as having elevated levels of allergen-specific IgE. This was due to an as yet unconsidered parameter of the RAST, i.e. unspecific binding of the radioactive tracer to the wall of the test tubes, resulting in values that did not correlate with the total IgE concentrations of individual sera. The unspecific binding amounted in some cases to 89% of the total radioactivity (counts/min) when the instruction manual of the manufacturer was followed. This resulted in either false positive results and/or RAST classifications that were 1 to 2 classes too high. The results can be corrected by a slight modification of the assay.

Allergens↗
PubMed1990

[Various forms of humidifier lung].

Clinical and immunological investigations of 15 workers in a repro-printing house revealed a prevalence of 7% for the occurrence of humidifier-lung. Serological sensitization to humidifier water and fungi respectively was found in 73%, fragmentary symptoms in 53%. In comparison to smokers, elevated antibody levels occurred more frequently in nonsmokers (33% vs. 100%). The results are supposed to reflect subclinical stages of disease, but they are not yet of a definite predictive value. Reduction of microorganisms in humidifiers seems to be essential for the prevention of disease.

Adult↗
PubMed1990

[Bronchial asthma in a hairdresser caused by hair bleach].

Three years after starting to work as a hairdresser a 33-year-old woman developed urticaria on contact with hairbleach. After a further four years rhinoconjunctivitis set in and later also bronchial asthma on contact with such bleaches. Extensive tests revealed hypersensitivity to widely used persulphate-containing bleaching liquids which ultimately forced the patient to give up her profession. The causative role of this group of chemicals was proven by positive skin tests and specific workplace-related provocation tests. But specific IgE antibodies could not be demonstrated. The findings suggest a pseudoallergic reaction.

Adult↗
PubMed1990

[Occupational respiratory tract allergies].

Numerous occupation-related substances of plant, animal, microbial and chemical origin are potent immunogens and allergens. In the Federal Republic of Germany, the most common form of occupational obstructive airways disease is baker's asthma, caused by the inhalation of flour dust and other related substances. Compliance with the industrial threshold limit values (TIL) at the workplace reduce the risk of contracting disease, but cannot exclude it completely. Apart from obtaining a detailed history, and performing a physical examination, the diagnostic work-up also requires inclusion of special allergy tests (prick, intradermal, RAST)--in equivocal cases also, after a prior exposure--free preparatory period, re-exposure and inhalative work-place-related provocative testing. Therapeutically, elimination of exposure heads the list of measures; in concrete terms, this can also mean a change of occupation or even occupational re-training.

Allergens↗