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Biomedical subjects

U Wahn

Publications and source records attributed to U Wahn.

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

[The allergy syndrome in childhood. Immunologic principles--risk factors--prevention].

The time of manifestation, severity and clinical course of atopic diseases are primarily determined by genetic factors. However, a number of environmental influences, like exposure to allergens and adjuvant trigger factors are modulating the clinical course. The risk for atopic disease can be predicted from cord blood IgE levels and the atopic family history of first degree relatives. Since no predictor is of sufficient sensitivity and specificity, there is a need for further predictors of atopy. Different prevention strategies, i.e. effect of early infant diet and maternal food avoidance during pregnancy or lactation are discussed.

Allergens↗
PubMed1991

[Therapy of status asthmaticus in childhood. A current review].

The treatment of acute severe asthma in childhood should be focused on the control of bronchial obstruction and on the prevention of mechanical ventilation. These aims can only be achieved by a rapid and vigorous procedure using multiple therapeutic concepts. beta 2-Mimetics still play a major role. The inhalative route has priority; if necessary, even a continuous nebulization can be carried out. In some cases the intravenous route is of additional help. Corticosteroids should be administered parenterally and in high doses. Supplying oxygen has to be amongst the first therapeutic steps in ventilatory disorders with impending respiratory insufficiency. Mechanical ventilation should be undertaken in a gentle hypoventilating way under sedation and relaxation. Main attention has to be paid to preventive measures in order to ensure out-patient care with a maintenance therapy including antiinflammatory agents.

Administration, Inhalation↗
PubMed1990

Oral immunotherapy with grass pollen in enterosoluble capsules. A prospective study of the clinical and immunological response.

In a prospective study spanning 2 years, 60 patients with grass pollen allergy were treated with either a low dose oral, a high dose oral or a subcutaneous hyposensitization regime. No significant improvement was seen in the orally treated patients whereas those on the subcutaneous hyposensitization regime demonstrated a decreased specific cutaneous reactivity, a rise in specific IgG antibodies and a reduction in symptoms. This study suggests that oral hyposensitization, even with enterosoluble grass pollen capsules, is ineffective.

Administration, Oral↗
PubMed1990

Spontaneous histamine release from washed leukocytes and whole blood in atopic and non-atopic individuals.

The ability of basophils from patients with allergic rhinitis, extrinsic asthma, chronic idiopathic urticaria and atopic dermatitis to release histamine spontaneously in vitro was studied. Spontaneous release in the presence and absence of 30% D2O was investigated from both washed leukocytes and whole blood. Compared with controls histamine release (HR) from washed leukocytes was significantly enhanced in allergic rhinitis patients only, whereas in the other groups only a certain percentage of patients was found to have high spontaneous HR. In whole blood experiments HR in all groups was within the normal range. Our data indicate that enhanced spontaneous mediator release from washed basophils in vitro does not necessarily prove this mechanism to be of pathophysiological relevance in vivo.

Adolescent↗
PubMed1990

IgE-mediated allergic reactions to potatoes.

We investigated sera of 12 patients with IgE-mediated hypersensitivity reactions to potato, using different in vitro methods. Radioallergosorbent test classes 2-4 (7.6-46.5% binding) were measured with potato allergen disks. Immunoblot detected allergen bands with an isoelectric point range of approximately 4.5-5.2 and mainly in a molecular weight range between 16.00 and 30.00 kD. But also at molecular weights of 43.00 and 65.00 kD allergen bands (IgE specificities) could be detected. Histamine release assay performed with isolated fractions of the potato extract showed a great individual variation and positive results of fractions of molecular weights between 10.00 and 80.00 kD. From our data we conclude that raw potato is a 'multiallergenic' vegetable.

Adolescent↗
PubMed1990

[Allergic reactions in treatment with L-asparaginase. Significance of specific IgE antibodies].

The formation of specific IgE antibodies to L-Asp was studied in 27 children with ALL. Increased titers of specific IgE antibodies were significantly more frequent (p less than 0.001) prior to L-Asp infusions followed by allergic reactions than in those without reactions. After passive sensitization of basophile granulocytes of a healthy volunteer using patient's serum with the highest titers of specific IgE antibodies to L-Asp a significant release of histamine was observed after exposure of cells to L-Asp. In 1 of 8 patients with allergic reactions titers of specific IgE antibodies were elevated, while there was not detectable activation of the complement system. In conclusion, elevated titers of specific IgE antibodies to L-Asp are frequently detectable prior to L-Asp infusions which are associated with allergic reactions. In addition to activation of the classical complement pathway specific IgE antibodies and mediator release from mast cells may contribute to clinical symptoms. In a small number of patients this mechanism alone may be responsible for the allergic reaction.

Adolescent↗
PubMed1990

[Seasonal variations in house dust mite allergens--significance for children with allergy].

Allergenic proteins of the house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae and their major allergens Der p I and Der f I are one of the most significant environmental factors which may facilitate sensitization and allergic airway disease in childhood. In order to measure seasonal variations of mite allergen exposure, we collected mattress dust samples monthly in 13 homes over a period of 1 year. Der p I and Der f I were determined with a sandwich type ELISA. Mite allergen levels were significantly lower from January-June than from July-December (p less than 0.05) which was mostly due to Der p I variations. Only in 6 of the studied homes seasonal variations in mite allergen concentrations according to seasonal variations in outdoor humidity could be observed. In 7 homes mite allergen exposure stayed constant and seemed to depend only on indoor climate factors.

Allergens↗
PubMed1989

[HIV infection in children of seropositive mothers].

Both resolved and still open questions are discussed. The natural course of HIV infection from the time at which a child becomes symptomatic is known. The incidence rate of HI-virus transmission to the child remains uncertain. Likewise the time of transmission and its cofactors as well as data about the incubation and latency periods remain open questions. The greatest problem thus, is the early and reliable definition of HIV infection. Initial results from prospective HIV-perinatal studies are presented, showing that a transmission rate between 20% and 40% is to be reckoned with.

Child, Preschool↗
PubMed1989

High mite-allergen exposure increases the risk of sensitization in atopic children and young adults.

Concentrations of major allergens of Dermatophagoides pteronyssinus (Dpt) and D. farinae (Df), Der p I and Der f I, were determined in 183 dust samples of mattresses of 133 atopic and 50 nonatopic children by a sandwich-type ELISA. Atopic children and young adults living in houses with high levels of Der p I and Der f I (greater than or equal to 2000 ng/gm of dust) were found to have significantly higher serum IgE levels to Dpt and Df (p less than 0.0001) compared to patients with low mite-allergen exposure. Washed leukocytes of 55 atopic children and 14 control subjects were investigated for in vitro histamine release to serial dilutions of Der p I; 86% of highly exposed (greater than or equal to 10,000 ng/gm) children demonstrated positive histamine release in response to Der p I compared to 17% in the group with very low exposure (less than 400 ng/gm). There was a positive correlation between basophil sensitivity (rs = 0.6; p less than 0.0001) and reactivity (rs = 0.54; p less than 0.0001) to Der p I and mite-allergen exposure. The relative risk for sensitization in the highly exposed group versus the group with very low exposure was sevenfold to 32-fold increased. We conclude that high concentrations of mite allergen (greater than or equal to 2000 ng/gm) increase the risk of specific sensitization in atopic children and young adults and thus may facilitate allergic airway disease.

Adolescent↗
PubMed1989

[Possibilities and limitations of hyposensitization treatment in airway allergies].

Beside pharmacotherapy specific hyposensitization is well accepted in the treatment of allergic airway diseases. During the therapy allergen extracts are injected in low concentrations subcutaneously, and dosage is gradually increased in order to induce clinical tolerance in patients. For pollinosis the efficacy of the therapy is well documented, although its immunological mechanisms are not known up to now. So far, its value for the treatment of bronchial asthma is still discussed controversially. The effectiveness of oral hyposensitization has not been demonstrated yet.

Allergens↗
PubMed1988

Immediate hypersensitivity to ovalbumin in children with hen's egg white allergy.

Serum concentrations of IgE, IgG1 and IgG4 antibodies to ovalbumin and basophil sensitivity to ovalbumin were compared with the results of a titrated oral provocation test with ovalbumin in 27 children sensitive to hen's egg white, of whom 17 responded with an immediate hypersensitivity reaction. Neither the serum level of IgE, IgG1 and IgG4 antibodies to ovalbumin nor a positive histamine release test predicted the clinical relevance of ovalbumin sensitivity. The children with a positive challenge test had a significantly higher IgE/IgE4 ratio and tended to be younger and to have higher serum IgE levels and a higher IgG1/IgG4 ratio than those with a negative challenge test. We conclude that an oral provocation test is necessary to confirm the diagnosis of food allergy.

Child↗
PubMed1988

Prospective study on immunologic changes induced by two different Dermatophagoides pteronyssinus extracts prepared from whole mite culture and mite bodies.

Twenty-four children with bronchial asthma and hypersensitivity to Dermatophagoides pteronyssinus by skin titration, specific serum IgE, leukocyte histamine release, and bronchial challenge test were selected for immunotherapy with two partially purified mite extracts. On the basis of age and allergen-specific IgE responses, patients were randomly divided for treatment with either an extract prepared from whole mite culture (WMC) or from purified mite bodies (MB). The content of major allergens was quantified for both extracts. The allergen dose administered during immunotherapy was increased up to the highest tolerated dose. The mean cumulative dose of Der p I was 98.9 micrograms for the WMC-treatment group and 76.7 micrograms for the MB-treatment group. Small, but statistically significant, decreases in RAST and crossed radioimmunoelectrophoresis responses to major allergens were recorded after 2 years of treatment. A small increase in specific IgG1 and a large persistent increase in specific IgG4 was recorded in both groups. There was a significant decrease in allergen-specific bronchial sensitivity, skin reactivity, and leukocyte sensitivity in both treatment groups. Between both groups, changes in the different parameters were not significantly different. Our data indicate that immunotherapy with both partially purified house dust mite extracts, WMC, and MB leads to a decrease in allergen-specific IgE responses and induce a response in specific IgG4. Both extracts are comparable in modulating leukocyte and skin sensitivity, as well as bronchial reactivity to mite allergens.

Allergens↗
PubMed1988

[How many newborn infants have an increased risk of atopic disease?].

Children of atopic parents as well as newborns with an increased cord blood IgE-level have a increased risk to develop atopic symptoms later in childhood under the influence of certain environmental factors. Out of 1203 newborns there were 3% with a biparental history of atopy and 9% with a cord blood IgE higher than 0.9 kU/l. Boys showed elevated cord blood IgE-concentrations more frequently than girls. There were no differences in IgE-levels between Turkish and German neonates. The effectiveness of preventive measures against atopic diseases should be studied in defined high risk groups, before a screening for atopy is considered.

Cross-Sectional Studies↗
PubMed1986

[Immunologic methods of study for evaluating the risk of anaphylactic reactions in intradisk chymopapain injections].

According to results available to date, skin tests are of limited value in determining the risk of anaphylactic shock. By identifying specific IgE antibodies, e.g. via the Chymo-FAST test or the corresponding RAST, the risk of anaphylactic shock of 0.2%-1% in the total group of patients can be reduced to 0.05% in patients in whom the test was negative, whereas in test-positive patients the risk is above 60%. Previous intolerance reactions among the remaining 0.05% are probably due to a non-testable pseudoallergic reaction, just like the 6% mild late reactions after the injection. For the remaining risk of 0.05% in IgE-negative patients drug prophylaxis with antihistamines or if necessary even steroids will continue to be mandatory. Examination of histamine release from leucocytes, which can be conducted in very few centres only, may possibly be able to clarify in future to what extent reinjection is permissible if a disc on a different level is affected, besides other scientific problems.

Anaphylaxis↗
PubMed1986

Allergen-specific IgE antibodies against antigenic components in cow milk and milk substitutes.

Crossed radioimmunoelectrophoresis (CRIE) was used to study the presence of serum IgE against antigenic components of cow milk in 21 selected milk-allergic patients. The amount of each IgE specificity was estimated by a scoring system. The milk-allergic children had mainly IgE against alpha-lactalbumin, beta-lactoglobulin, albumin and immunoglobulin, the four major proteins of bovine whey, as well as IgE against three casein components. A serum pool from 1000 normal adults had IgE against the same whey protein, but in smaller amounts, and no IgE against the casein components. Eight cow milk-based formulae, commonly used for infant feeding, and goat milk were studied by the same method. It was found that six of the milk substitutes did not differ significantly from cow milk in antibody binding, but the two hydrolysed casein products, Nutramigen and Pregestimil, consisted of such small molecules that the rabbit antisera could not precipitate the hydrolysed proteins in the gels on the CRIE plates. It was therefore not possible to study their IgE binding, if any, by this method.

Adult↗