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X Baur

Publications and source records attributed to X Baur.

At least 163 records · Page 9Linked to original sources
PubMed1995

Diagnostic validation of specific IgE antibody concentrations, skin prick testing, and challenge tests in chemical workers with symptoms of sensitivity to different anhydrides.

BACKGROUND: The diagnostic possibilities of sensitization to various acid anhydrides are limited because of the lack of standardized allergens for the different test systems. This makes the diagnosis of IgE-mediated sensitization caused by occupational exposure difficult. METHODS: We prepared conjugates of human serum albumin with phthalic, maleic, trimellitic, and pyromellitic anhydrides to be used for IgE estimation by enzyme-allergosorbent test, skin prick tests, and nasal and bronchial challenge tests. Nine anhydride workers, who complained of various respiratory symptoms, were studied. RESULTS: Of the nine workers, four had immediate-type skin test responses to one or more conjugates. All four subjects had elevated IgE concentrations in addition to two other workers. Three of six nasal challenges and four of nine bronchial challenges resulted in positive responses. All but one of the positive nasal or bronchial test responses were associated with elevated IgE levels. The seven positive challenge test results included five positive skin test responses. On the other hand, in all but two of the subjects with negative challenge test results, no specific IgE could be detected. In these two subjects the negative results were associated with low levels of IgE, and in one, with the absence of asthma. None of the results of tests with unconjugated anhydrides were positive. CONCLUSIONS: Anhydrides investigated in this study can induce IgE-mediated hypersensitivity, which can be diagnosed by using the respective human serum albumin in estimation of specific IgE and in skin, nasal, and bronchial challenge tests. Estimation of IgE was demonstrated to be more sensitive than skin prick testing.

Anhydrides↗
PubMed1995

Cross-reacting IgE antibodies recognizing latex allergens, including Hev b 1, as well as papain.

The cross-reactivity of IgE antibodies recognizing epitopes of latex allergens and papain was studied in sera of 36 latex-exposed subjects and 22 papain workers. Eight out of 24 latex-sensitized persons also showed a positive reaction to papain in the CAP assay (mostly of low or moderate degree). On the other hand, six out of the 12 sensitized papain workers also revealed IgE binding to latex allergen(s). Reciprocal inhibition experiments confirmed that groups monosensitized to one of the two allergens can be separated from a group showing partial or nearly complete immunologic cross-reactivity. Papain inhibited IgE binding by 20-33% in these subjects, whereas IgE binding to papain was strongly blocked in most cases. Comparison between the primary sequences of Hev b 1, a major latex allergen, and papain suggests that the cross-reactivity may be due to several identical trimers and tetramers.

Allergens↗
PubMed1995

Allergic reaction after eating alpha-amylase (Asp o 2)-containing bread. A case report.

A 29-year-old female bakery shop assistant was occupationally sensitized to flour allergens and Aspergillus alpha-amylase (Asp o 2). The latter represents a strongly allergenic component of routinely used baking additives. The patient had repeatedly responded to the consumption of white bread with rhinitis, conjunctivitis, and, occasionally, wheal and flare reactions. She underwent allergologic investigations including oral challenge tests with commercially available bread loaves. Elevated specific IgE antibodies against bread extracts, Asp o 2, and flour allergens were detectable in her serum. The provocation test with bread resulted in a running nose together with a strong increase in nasal resistance. All symptoms subsided about 3 h after the challenge. None of the above symptoms could be observed when bread free of Aspergillus alpha-amylase was administered. This outcome provides evidence of a clinically relevant persistent allergenicity to Asp o 2 in bread.

Adult↗
PubMed1995

[Respiratory tract diseases caused by chemically irritating or toxic pollutants at the work site].

Update statistics of job-related diseases show there is still a high level in reported and also in recognised and financially compensated airway diseases caused by the action of chemically irritating or toxic substances during work. Most reported cases occur in the chemical and metal processing industries. Main triggering substances are said to be isocyanates, aerosols of pollutants produced during welding, cutting, casting or moulding (smoke), by solvents and hair dyes. Experiments prove that a variety of these noxious substances produce dose-dependent hypersensitivity of the bronchial system. Long-term monitoring of granary workers clearly points to both the possibility of and the need for early diagnosis followed by mandatory and immediate abstention from further exposure to avoid occurrence of irreversible disease patterns. Work-related health risks over and above job-conditioned diseases must be generally included in the protective measures in accordance with the new EC guidelines.

Air Pollutants, Occupational↗
PubMed1995

[Induction of rat liver foci by inhaled diisocyanate exposure].

Diisocyanates are increasingly used for manufacturing polyurethane foam, elastomers, adhesives, coatings, insecticides and many other products. The large number of workers being exposed to these chemicals has a concentration-dependent risk of developing chronic airway disorders. The clinical role of genotoxic effects of diisocyanates demonstrable in vivo and in vitro is still unclear just as their possible cancerogenic potential. The possible initiating effect of diisocyanates in liver carcinogenesis was studied using a rat liver foci bioassay (RFLA). The RLFA is based on the histochemical demonstration of foci of hepatocytes with altered enzyme equipment, which are induced by carcinogens. These foci are generally regarded as early preneoplastic lesions. Rats were exposed either to 20 ppb TDI (Toluene diisocyanate) or 20 ppb HDI (Hexamethylene diisocyanate) for two hours a day over a period of four weeks. After a break of one week the rats received 10 mg Clophen A50/kg body weight as promotor for possible isocyanate induced tumorigenic lesions twice a week for eight weeks. For positive control the hepatocarcinogen diethylnitrosamin (DEN) was given as a single dose of 10 mg and 20 mg. All animals were sacrificed aged 16 weeks. Serial cryostat sections were prepared for ATPase and gamma GT staining. The foci number was determined and calculated as foci/animal as a mean value taken from both staining protocols. Preneoplastic liver foci were observed in positive control rats treated with a single dose of 10 mg as well as with 20 mg DEN (4.3 +/- 3.2 and 1.8 +/- 1.4 respectively). In none of the animals exposed to TDI or HDI preneoplastic foci were detectable.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants, Occupational↗
PubMed1995

[Components of hair bleaches as triggers of bronchial hypersensitivity--studies using a model for occupationally-induced lung damage].

Ammonium persulfate (APS) is used as an oxidant in many industrial branches and is contained in bleaching substances used in hair cosmetic industry. In addition to skin diseases, respiratory disorders have been frequently reported. We examined whether APS can induce bronchial hyperresponsiveness (BHR) which has to be regarded as a first step in the development of obstructive respiratory disorders. In a rabbit model we tested the influence of aerosolized APS-solutions in concentrations of 0.1, 0.01 and 0.001 M (50, 5, 0,5 ppm in air) for about four hours on the contractile bronchial reaction. Exposure to APS-aerosols does not alter basal airway Resistance (RI), dynamic Elastance (Edyn), slope of inspiratory pressure generation (delta Poes/tI), arterial blood pressure and blood gases (PaO2, PaCO2). Before, after two and after four hours the influence of APS application on the bronchial reactivity to 0.2%- and 2% acetylcholine-aerosols (ACH) was tested. Exposure to an aerosol from 0.1 M APS solution, which is equivalent to a concentration of 50 ppm APS in air for two hours induces a significant increase in bronchoconstrictory responses to ACH. A nebulized 0.01 M APS solution causes an increased ACH response after four hours of exposure. However, inhalation of 0.001 M APS (0.5 ppm in air) does not alter sensitivity to ACH within four hours of exposure. In bronchoalveolar lavage an increased number of inflammatory cells was found. Our results demonstrate, aerolized APS-solutions to cause bronchial hyper-responsiveness after few hours of exposure presumably under the participation of inflammatory cells.

Aerosols↗
PubMed1995

[Pilot project for evaluation of lung function reference values].

Lung function tests were performed in this study on 139 adults (mean age 36 years), as well as on 91 female persons between 16 and 18 years of age (the latter just starting on their professional careers), the lungs being healthy in each case in both groups. The findings were compared with the currently accepted reference value formulae after Quanjer et al., and Zapletal as well as further developed reference value formulae after Brändli et al., Most of the measurement data obtained by spirometry for the BGFA group of probands are between the two recommended reference values for adults with better coincidence with Brändli's predictions (exceptions being MMEF25-75 MEF 50 and MEF 25). In our studies we obtained higher values than the reference median values after Quanjer and Zapletal for IVC, FVC, FEV1 and PEF by 6-8% and 5-15%, respectively, whereas the values for adults differ from the predictions made by Brändli et al. by -4% to +5%. The flow data MMEF 75-25, MEF 50 and especially MEF 25 are set at too low levels (by 5-23%) by Zapletal's and Brändli's values. Comparatively, the values predicted by Quanjer et al. for the above mentioned flow-volume parameters (with the exception of MEF 75) are too high by 4% to 12%. There are also considerable differences in respect of the reference values for IGV to the tune of +15% in the BGFA group compared to Quanjer et al.; in the BAFAM group the values differ from those of Zapletal et al. by +17%. RV yields results in the BGFA group which are higher by 11% than according to Quanjer's formulae, whereas in the BAFAM group they are higher by 15% compared to Zapletal's predictions. In respect of Rt there are differences to the predictions by Rühle and Matthys by +16% (BGFA group) and +13% (BAFAM group), respectively. The BAFAM group differs from Zapletal's predictions by +11%. Looking at the reference limit values the overall impression is confirmed that the predictions after Quanjer et al. and mostly also those by Zapletal are too low in respect of the abovementioned lung function parameters (in the majority of cases not 5% of the examined probands, as expected, are below those levels, but only about 2%). Females, who had been underrepresented in the previous healthy proband groups, show larger deviations than males in respect of most of the parameters.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1995

[Measuring single breath diffusing capacity in a patient sample with healthy lungs--comparison with the European Coal and Steel Community standard values].

The measurement values of the diffusion parameters TLCO (diffusion capacity) and KCO (transfer coefficient) of 107 healthy subjects not suffering from pulmonary diseases were compared with the EC/European Community for Coal and Steel (ECCS) standard value formulas (2-5). The diffusion parameter KCO is markedly better described by the 1993 standard value formula than by the 1983 ECCS version. Men yield higher measured values than predicted by the 1993 EC formulas. The diffusion parameters of smokers are significantly lower than those of non-smokers.

Adolescent↗
PubMed1994

Conformations of peptide fragments comprising the complete sequence of component III of Chi t I and their relationship to T-cell stimulation.

Conformational preferences of synthetic peptides that span the complete sequence of Chironomus thummi hemoglobin (Chi t I) component III were studied by nuclear magnetic resonance (NMR) and CD spectroscopies. The peptides, 19-21 amino acids in length, were studied in water, except for the C-terminal peptide, which was investigated in DMSO-d6. NMR showed that all investigated peptides lacked uniquely folded conformations in water at 4 degrees C and pH 3.0 or at 10 degrees C and pD 6.6 in DMSO. However, some preferential helix-like conformations for the peptides corresponding to the helices of the folded protein could be seen in solution. These peptides showed characteristic interactions for conformations in both the beta- and alpha-regions of phi-psi space, based on strong C alpha H(i)-NH(i + 1) interactions, and on NH-NH, C alpha H(i)-NH-(i + 2), C alpha H(i)-NH(i + 3), and C alpha H(i)-C beta H(i + 3) interactions, respectively. Helical motifs seem not to be the most important factors in determining MHC-binding and/or T-cell recognition. However, there is a tendency that more stabilized secondary structures show higher T-cell stimulation.

Allergens↗
PubMed1994

[Are amylases in bakery products and flour potential food allergens?].

The enzyme alpha-amylase from the mould Aspergillus oryzae (Asp o II) routinely used for the production of bread, cakes and pastries has in recent years been identified as an inhalative allergen for occupational diseases (bakers' asthma). It is doubtful whether this amylase in the final product, i.e. after the baking procedure, can still be regarded as an allergen. To clarify this question, detailed case histories on 138 subjects were recorded (98 allergics, 20 patients suffering form chronic intestinal diseases, 20 healthy controls). The clinical examinations included prick skin test and IgE antibody determination using one of the customary enzyme preparations. EAST showed a few of these 138 bread consumers to be weakly sensitized to the enzyme. One of the subjects displayed a significant reaction to alpha-amylase heated to 200 degrees C. As expected, eleven bakers sensitized to alpha-amylase by inhaling it in the workplace (positive prick test, positive case history) predominantly exhibited specific IgE antibodies to the native enzyme. Apart from one weakly positive finding, heated alpha-amylase yielded negative results in this collective. Baking conditions vary widely, especially with regard to single components, temperature and duration. Thus, further investigations as to residual allergenicity or the feasible occurrence of new antigenic determinants during the production of bread, cake and pastries are required. 27% of bakers examined and 9% of atopics showed antibodies to a flour inherent enzyme, a beta-amylase. On the whole, the selected conditions hinted at a weakly sensitizing potential inherent in baking flour and in added amylase.

Allergens↗
PubMed1994

Immunogenetic studies on HLA-DR in German coal miners with and without coal worker's pneumoconiosis.

Coal worker's pneumoconiosis is caused by the pulmonary deposition of coal dust, including silica particles. Several factors such as chemical composition and physical properties of silica-containing dust, particle size distribution, intensity, and duration of exposure influence the disease development. Genetic factors may also be involved. To define whether HLA-DRB may function as a genetic factor for predisposition to coal worker's pneumoconiosis, we determined DRB1, 3, 4, 5 alleles. For this purpose, DRB typing with sequence-specific oligonucleotide probes in 204 German miners with pneumoconiosis and in 52 German miners without pneumoconiosis was used. The miners had worked under comparable conditions. The frequency of DR8 (1*0801-0804) was increased in patients developing pneumoconiosis during the first 15 years of mining (p = 0.047). The frequency of DR1 (1*0101-0103) was elevated (p = 0.022) and that of DR52 (3*0101, 3*0201, 3*0202, and 3*0301) was reduced (p = 0.026) in miners without pneumoconiosis. Our data show that the presence of DR1 and the absence of DR52 support the resistance to coal worker's pneumoconiosis. Furthermore, DR8 may be involved in the rapid development of coal worker's pneumoconiosis.

Adult↗
PubMed1994

Respiratory and other hazards of isocyanates.

Isocyanates are increasingly being used for manufacturing polyurethane foam, elastomers, adhesives, paints, coatings, insecticides, and many other products. At present, they are regarded as one of the main causes of occupational asthma. The large number of workers who are exposed to these chemicals have a concentration-dependent risk of developing chronic airway disorders, especially bronchial asthma. Different pathophysiologic mechanisms are involved. Immunoglobulin E (IgE)-mediated sensitization and irritative effects have been clearly demonstrated in both exposed subjects and animals. Presumably, neural inflammation due to neuropeptide release of capsaicin-sensitive afferent nerves is crucial. We collected data on 1780 isocyanate workers who had been examined by our groups. Of them 1095 (including subjects from outpatient departments) had work-related symptoms, predominantly of the respiratory tract. Specific IgE antibodies were found in 14% of the 1095 subjects. The methacholine challenge test was shown to be an inadequate predictor of the results of inhalative isocyanate provocation tests in workers and in asthmatic controls. Isocyanate (toluene diisocyanate TDI) air concentrations of 10 ppb (0.07 mg/m3) and 20 ppb (0.14 mg/m3), respectively, did not cause significant bronchial obstruction in the majority of previously unexposed asthmatics with bronchial hyperreactivity. IgG-mediated allergic alveolitis, a rare disease among isocyanate workers, was found in approximately 1% of the symptomatic subjects. Experimental studies exhibit dose-dependent toxic effects and give evidence for tachykinin-mediated bronchial hyperreactivity after exposure to isocyanates. The clinical role of genotoxic effects of isocyanates and their by-products demonstrated here in vitro and in vivo has yet to be clarified.

Air Pollutants, Occupational↗
PubMed1994

Association of class II sequences encoding DR1 and DQ5 specificities with hypersensitivity to chironomid allergen Chi t I.

A panel of 188 unrelated Caucasian subjects who were exposed to the larvae of Chironomus thummi (Diptera, nonbiting midges) was HLA-typed by polymerase chain reaction amplification of the second exons of the DRB, DQA1, and DQB1 genes followed by dot-blot hybridization with sequence-specific oligonucleotide probes. Type I sensitization to the allergen Chi t I and a large number of other inhalant allergens was determined by RAST and skin testing. Sixty-one individuals were found to be sensitized to Chi t I, of whom 24 were sensitive to this allergen and to no other allergens tested. Statistical analyses showed that only in the latter group were the HLA-D genes DRB1*0101, DQA1*0101, and DQB1*0501 associated with IgE-responsiveness to Chi t I. These results suggest that HLA associations with responsiveness to certain allergens may be more striking in monosensitized subjects.

Adolescent↗
PubMed1994

Analysis of B-cell epitopes in the N-terminal region of Chi t I component III using monoclonal antibodies.

The hemoglobins of the midge Chironomus thummi thummi (Chi t I) are known to cause immediate-type hypersensitivity reactions in humans. Further knowledge of the antigenic sites of such allergens will provide new therapeutic approaches. The aim of our study was to identify and characterize linear B-cell epitopes of the hemoglobin component III of Chi t I (136 amino acid residues). Using the antigenic index algorithm of Jameson and Wolf (Jameson and Wolf (1988) Comput. Appl. Biosci. 4, 181-186), three linear binding sequences of this allergen molecule were predicted. Two mouse monoclonal antibodies (mAbs 3 and 6) raised against purified Chi t I component III were investigated by ELISA for their binding to nine synthetic peptides 19-21 residues in length, covering nearly the whole sequence of component III. MAb 6 recognized only one peptide (11-30) while mAb 3 bound to both N-terminal peptides (1-19 and 11-30), suggesting that the antibody binding site is located in the overlapping region. This assumption could be confirmed in ELISA with solid phase-bound recombinant peptides (RP) as well as in inhibition studies with free tryptic peptides indicating that identification of these linear B-cell epitopes is neither influenced by the method of peptide production nor by the kind of used immunoassay. To define the essential amino acid residues we investigated mAbs with solid phase-bound overlapping octamers. In the case of mAb 3, amino acids experimentally identified as essential for antibody binding (aa 13-17) are identical with those residues predicted as a B-cell epitope with the antigenic index of Jameson and Wolf.

Allergens↗
PubMed1994

Isolation and denomination of an important allergen in baking additives: alpha-amylase from Aspergillus oryzae (Asp o II).

The commercially available alpha-amylase from Aspergillus oryzae which is widely used as a baking additive was compared with a highly purified enzyme preparation. We used enzyme allergosorbent test (EAST), EAST inhibition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focussing, immunoblotting, and N-terminal amino acid sequencing to characterize the causative allergen. Our screening comprised 89 partially selected bakers. Forty-three (48%) of them had work-related respiratory symptoms; 14 (32%) of whom were sensitized to the baking additive. Significant immunological differences could not be found between crude and purified sample with the exception that the latter one produced nearly twice as high antibody values. Iodine starch staining demonstrated that the component which was exclusively or predominantly bound by IgE antibodies of symptomatic bakers represents the active alpha-amylase. According to the International Union of Immunological Societies (IUIS) nomenclature, the term Asp o II is suggested for this important occupational allergen.

Allergens↗
PubMed1994

Chironomidae hemoglobin allergy in Japanese, Swedish, and German populations.

Hemoglobins of the Diptera (insect) family Chironomidae have been identified as causative allergens in asthmatic patients. In this study, 229 Japanese, 17 Taiwanese, and 92 Swedish sera from atopic patients were tested for antibodies against Chi t I, the hemoglobin from the European midge species Chironomus thummi, and against crude extracts from the Japanese midges Tokunagayusurika akamusi (T. akamusi) and Cricotopus sylvestris (Cr. sylvestris). Nearly 40% of patients showed a positive reaction to Cr. sylvestris extract, which contains no hemoglobin. This result is probably due to the presence of other partially cross-reacting allergens than hemoglobin. Nearly all tested Japanese serum samples showed cross-reactivity between Chi t I and Cr. sylvestris, a finding which is evidence for common epitopes in both midge species. Furthermore, an overall good correlation between the amounts of IgE antibodies against Chi t I and Chi t I component III was found in sera from Swedish, Japanese, and German patients.

Allergens↗
PubMed1994

Allergen-induced expression of cell surface markers on lymphocytes of Chi t I-sensitized patients.

Lymphocyte cultures of persons sensitized to the hemoglobin allergen Chi t I show a highly significant response to the allergen measured in the lymphocyte stimulation assay by (3H)-thymidine uptake. In this study, we investigated by flow cytometry the expression of different cell surface markers on lymphocytes after in vitro stimulation for 7 d with or without the allergen Chi t I. We determined the expression of the low-affinity receptor for IgE (CD23) on lymphocytes of Chi t I-sensitized patients and Chi t I-exposed as well as nonexposed controls. CD23 expression was significantly higher in patients than in nonexposed controls. Exposed but healthy subjects showed intermediate values. We also determined the expression of activation markers CD25 (IL-2 receptor) and HLA-DR on the lymphocytes of patients and nonexposed controls. HLA-DR expression on non-T cells (CD3-) was significantly higher in patients than in controls. HLA-DR on T cells (CD3+), and CD25 as well as CD23 expression, could be significantly enhanced after antigen-specific stimulation in patients but not in controls, whereas alpha/beta-T-cell-receptor expression was significantly reduced in patients. Differences between patients and controls were not observed in response to tetanus toxoid (TT) and phytohemagglutinin (PHA). Our results demonstrate antigen-specific influences on the expression of cell surface molecules. These findings may be valuable diagnostic information.

Allergens↗