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Biomedical subjects

R Urbanek

Publications and source records attributed to R Urbanek.

At least 19 recordsLinked to original sources
PubMed1995

Characterization of antigens and allergens in hypo-allergenic infant formulae.

The antigenicity and allergenicity of so-called hypo-allergenic infant formulae is mainly determined by the degree of hydrolysis and ultrafiltration. Five different formulae were investigated by means of immunoblotting and RAST in order to characterize the antigens and allergens regarding their molecular weights, molecular origin and their ability to bind human IgG and IgE antibodies: A non hydrolysed infant formula (I-F), a mixture of the major cow's milk proteins (PM), a whey-based infant formula (W-H), a whey-based and ultra-filtrated infant formula (U-H), a casein/whey-based infant formula (CW-H). By immunoblotting we demonstrated that all tested formulae still contain antigens with molecular weights from 3 to 67 kD. But when compared with I-F and PM the antigen content of the hydrolysed formulae was considerably lower. The lowest antigen content could be demonstrated in U-H, which contains casein fragments (3-6 kD) and beta-lactoglobulin and its fragments (6-18 kD). W-H and CW-H contain bovine serum albumin, beta-lactoglobulin, casein and their fragments (3-67 kD). All hydrolysed formulae tested showed a reduced IgE-binding capacity. Three out of 12 cow's milk allergic children possessed IgE binding to U-H or W-H, and 5 of them IgE against CW-H. Conclusion. The enzymatic hydrolysis plus ultra-filtration seems to be the most efficient method to reduce the antigen content of so-called hypo-allergenic infant formulae.

Allergens↗
PubMed1995

Natural and recombinant enzymatically active or inactive bee venom phospholipase A2 has the same potency to release histamine from basophils in patients with Hymenoptera allergy.

BACKGROUND: A complementary DNA encoding the major bee venom allergen phospholipase A2 (PLA) has been characterized recently. Recombinant PLA was produced in Escherichia coli and purified to apparent homogeneity. Natural PLA was compared with recombinant PLA in its ability to release histamine from blood basophils. METHODS: A synthetic gene encoding the mature form of PLA was expressed in E. coli, and the polypeptide was purified to homogeneity by affinity chromatography and refolded, yielding fully enzymatically active PLA. In addition, we have produced a genetically engineered enzymatically inactive variant by substitution of a single amino acid residue in the catalytic center. A standard histamine release assay was used to compare the potency of natural PLA with correctly folded enzymatically active and inactive recombinant PLA to release histamine from blood basophils of nine patients with bee venom allergy. RESULTS: Recombinant enzymatically active PLA and purified natural protein were equally effective in releasing histamine from sensitized basophils. By comparing the histamine-releasing capacity of enzymatically active and inactive recombinant allergen, we further demonstrate that catalytic activity is not a requirement for allergenicity in the effector phase. Denaturation of natural PLA or incorrect folding of recombinant protein resulted in a total loss of allergenic potency. CONCLUSION: We demonstrate the feasibility of producing native-like recombinant allergens with or without enzymatic activity. We also provide evidence for the requirement of correct three-dimensional structure of PLA to induce histamine release from basophils and thus evidence for its recognition by IgE.

Bee Venoms↗
PubMed1995

Early sensitization to airborne allergens.

We report the case of a 7-month-old child with failure to thrive. Celiac disease was suspected because of highly raised antigliadin IgA and IgG antibodies and subtotal villous atrophy. In peripheral blood mononuclear-cells cellular proliferation was found in response to birch pollen, rye pollen and hazelnut extract. Born in June 1992 the infant had not yet experienced a birch pollen season. He had been fed with birch pollen allergy-associated carrot, apple and potato beginning at 6 weeks of life. In the serum, specific IgG, IgM and IgA to birch pollen and profilin, rye pollen and hazelnut antigens were detectable, indicating possible in utero sensitization or T cell cross-reactivity due to early sensitization with related food antigens.

Allergens↗
PubMed1995

Increased degranulation of eosinophil and neutrophil granulocytes in cystic fibrosis.

Increased serum and sputum concentrations of eosinophil cationic protein (ECP) and of neutrophil myeloperoxidase (MPO) have been described in patients with cystic fibrosis. Because numbers of eosinophils are normal in both peripheral blood and in the lung of patients with cystic fibrosis, we investigated whether eosinophils presented with an increased propensity to release their granule proteins. We investigated 20 patients with cystic fibrosis, 19 individuals with bronchial asthma, and 21 healthy nonatopic subjects. Isolated granulocytes were stimulated with serum-opsonized Sephadex G15 particles and the released amounts of ECP and MPO were measured by using radioimmunoassays. Eosinophils of patients with cystic fibrosis released significantly higher amounts of ECP than control subjects (p < 0.0001) and individuals with bronchial asthma (p < 0.0001). The release of MPO from neutrophils was also higher (p < 0.0001 and p < 0.005, respectively). Furthermore, a significant relationship between clinical variables and secretory activity of eosinophils was found in cystic fibrosis. We conclude that eosinophils as well as neutrophils obtained from patients with cystic fibrosis have an increased propensity to release their granule proteins which may be due to priming mechanisms. These findings would support anti-inflammatory treatment modalities in cystic fibrosis.

Adolescent↗
PubMed1992

Maternal smoking in early childhood: a risk factor for bronchial responsiveness to exercise in primary-school children.

The relationship between maternal smoking and bronchial hyperresponsiveness as assessed by a standardized free running test was investigated in a cohort of 1812 primary-school children in first grade. A child's exposure to maternal smoking during pregnancy, the first year of life, and the study year was recorded. Current exposure was not positively associated with bronchial hyperresponsiveness. The prevalence of this disorder was higher when maternal smoking during the child's first year of life was reported (9%) than when it was not (5.9%). The odds of being hyperresponsive were significantly higher in children exposed to maternal smoking in their first year of life (odds ratio, 2.82; 95% confidence interval, 1.25 to 6.34; p less than 0.01), especially in children with asthma (odds ratio, 20.55; 95% confidence interval, 2.5 to 168.9; p less than 0.01). Current exposure to maternal smoking was associated with less hyperresponsiveness. The effect of current maternal smoking might reflect changes in smoking habits by mothers of children with symptoms, whereas exposure to tobacco smoke in early life might be causally related to bronchial hyperresponsiveness. Our findings support the general hypothesis that early lung injuries have an impact on the later respiratory health of children.

Asthma, Exercise-Induced↗
PubMed1992

Early childhood risk factors for sensitization at school age.

Early childhood risk factors for current sensitization were investigated by use of cross-sectional data of a longitudinal study in Southwest Germany. Information was gathered by questionnaires from 1812 families of whom 1470 children 6 to 8 years old were tested by means of a skin prick test (SPT) with seven aeroallergens. Groups with sensitization (n = 201; positive SPT to grass pollens 6.6%, Dermatophagoides pteronyssinus 6.5%, Dermatophagoides farinae 4.4%, cat dander 4.6%, any of the tested allergens 13.7%) are compared with children without sensitization (n = 1269). As risk factors for any sensitization parental atopy (odds ratio [OR]/95% confidence interval [95%CI]: unilateral 1.9/1.3 to 2.6; bilateral 2.8/1.5 to 5.2), low gestational age (1.9/1.1 to 3.2), and male gender (1.6/1.2 to 2.3) are statistically significant in multiple logistic regression. Former cat ownership is significantly related to sensitization to cat dander (2.7/1.4 to 5.5). Breast feeding, maternal smoking habits after the child's birth, prior exposure to pets, and social class are not important. In conclusion, our data suggest parental atopy, low gestational age, and male gender as independent risk factors for sensitization to aeroallergens at school age.

Air Pollutants↗
PubMed1992

Longitudinal variability of skin prick test results.

The skin prick test (SPT) is a commonly used procedure for assessing a specific sensitization. The longitudinal variability of test results is of interest for clinical as well as epidemiological investigations. The sensitization to four common aeroallergens (grass pollen, birch pollen, Dermatophagoides pteronyssinus, cat dander) is investigated within the framework of three consecutive SPTs at 11-month intervals for a population of 587 schoolchildren. The prevalence of sensitization based on a weal diameter of at least 2 mm was between 12.9% (cat dander) and 23.9% (grass pollen) in the initial testing. The positive predictive values of the initial SPT were between 75.3% (birch pollen) and 88.2% (cat dander) for the two subsequent SPTs. In the case of initially negative tests with positive second and third SPTs the incidence ranged between 3.2% (cat dander) and 4.3% (birch pollen) per year. A clear increase in the intensity of reaction in subsequent tests was observed in a number of probands testing positively in the initial SPT. In conclusion, our data indicate a high long-term stability of a specific sensitization to aeroallergens in SPT.

Adolescent↗
PubMed1992

Clinical atopy and associated factors in primary-school pupils.

To investigate potential risk factors for clinical atopy in childhood, we obtained cross-sectional data from a cohort of 1376 8-year-old pupils. Parental atopy (hay fever, asthma, eczema), gestational age, maternal smoking habits, and the child's history of asthma, hay fever, and eczema were ascertained by questionnaire. Combining the history and the result of a skin prick test using seven aeroallergens, we defined the child's atopic diseases. Of the population evaluated, 25.4% were categorized as atopic (10.2% allergic asthma, 17.3% eczema, 6.9% hay fever). As compared with the clear nonatopics (40.2%), parental atopic diseases were more prevalent in each of the atopic groups. Significant associations of the parents' and child's disease were obvious for eczema and hay fever. Low gestational age (LGA) was more frequent in children with any atopy or with an allergic asthma (odds ratio (OR) 1.7; 95% confidence interval (CI) 1.02-2.97; OR 2.8; 95% CI 1.5-5.4). Hay fever and allergic asthma occurred less frequently in girls (OR 0.5; 95% confidence interval 0.3-0.8; OR 0.6; 95% CI 0.4-0.9). In conclusion, our data underline the importance of parental atopy for the clinical outcome in the offspring. In addition, LGA appears to be a risk factor for allergic asthma and for general atopy in later life.

Austria↗
PubMed1992

[Urinary N-methylhistamine excretion. Following exogenous histamine administration and allergy/exercise-induced bronchoconstriction].

Histamine is partly metabolized to a stabile metabolite N-methyl-histamine and excreted in the urine. We analysed the degradation of infused histamine and the N-methyl-histamine-excretion in atopic and normal individuals as in patients with a bronchoconstriction due to allergen/exercise challenge. N-methyl-histamine was determined by a newly developed radioimmunoassay. 60 controls and 38 atopic individuals were investigated. There is a proportional increase of N-methyl-histamine in the urine in young children. However, no significant difference between allergic and non-allergic individuals was found. After parenteral administration of a standardized amount of histamine 12% of the applied amount was secreted in the urine as N-methylhistamine. The most significant increase of N-methylhistamine-excretion was observed in the first hour after application. Only an 0.1% rise of N-methyl-histamine was observed following an oral administration of histamine. Neither bronchial challenge with specific allergen nor physical exercise elicited significant changes of N-methylhistamine excretion. The secretion of N-methyl-histamine demonstrates the degradation of histamine in the circulation, the measurement oft this metabolite in the urine should be considered when analysing the cause of severe systemic allergic reaction as anaphylaxis but not asthma or atopic disposition.

Adolescent↗
PubMed1991

[Neurodermatitis in childhood. Differential diagnosis--complications-- therapy].

The incidence of atopic dermatitis of 2-5% makes it one of the most common chronic diseases of childhood. In 80% of the patients, the skin symptoms first appear within one year of birth. In the differential diagnosis in infants, consideration must be given to candidiasis, seborrhoeic eczema and scabies; bacterial and viral superinfections are common complications. Approximately 80% of the victims have a disposition for atopy; in 50-80%, allergic rhinoconjunctivitis and/or bronchial asthma develops in addition. Despite recent progress in the understanding of the etiopathogenesis of atopic dermatitis, causal treatment is not yet in sight. For this reason, rational symptomatic treatment combined with exhaustive informative talks with and supervision of the children and their parents are of major importance for the management of this disease.

Child↗
PubMed1991

[Air pollutant burden and bronchial asthma in school children].

To examine the possibility of an effect of indoor and outdoor exposures on the prevalence of asthma in childhood we conducted a cross-sectional study in the area of Freiburg city and two communities in the Black Forest. The study group consists of 704 children aged 7 to 16 years. The children and their mothers took part in a standardized interview and a medical examination. Indoor exposures were assessed from information gathered in the interview by two different indices: (a) heating system and single room heating, and (b) the amount of indoor ventilation. The measurement of outdoor pollutants took into account weekly estimations of NO2 and combustion particles. The presence of asthma was recorded according to a previous medical diagnosis. Confounders were assessed during the interview (passive smoking, genetic predisposition to asthma etc.) or during the medical examination (cutaneous sensitization with a skin prick test). For the analysis of the data we applied logistic regression models and estimated odds-ratios. Only one of the four hypothesis variables displays a significant effect on the prevalence of asthma: Stoves as heating device carry a 4.8-fold relative risk for asthma compared to other types of heating. Among the confounding variables controlled for in the explanatory model, cutaneous reactions showed a relative risk of eight.

Adolescent↗
PubMed1991

Emergency treatment of allergic reactions to Hymenoptera stings.

Allergic reactions to Hymenoptera stings are frequently observed all over Europe. Rarely they may induce long-standing morbidity or even be fatal. Several investigations have shown that the emergency treatment given to these patients is often inadequate. Cutaneous symptoms respond well to antihistamines and also to adrenaline. Adrenaline is the mainstay for outside hospital treatment of more severe reactions involving the respiratory tract (bronchial asthma, laryngeal oedema) and the cardiovascular system (anaphylactic shock). Inhaled adrenaline is especially useful in respiratory symptoms, while parenteral application of adrenaline is prefered for shock treatment. All patients with severe respiratory or cardiovascular reactions must be hospitalized, treated under intensive care conditions and observed for at least 24 hr. Emergency medications including adrenaline for inhalation or for self-injection must be given to all patients with a history of systemic allergic reactions to hymenoptera stings. These patients must also get instructions for safety measures to avoid further stings. They should be referred to an allergist in order to evaluate the indication for venom immunotherapy.

Anaphylaxis↗
PubMed1991

Beta-2-adrenoceptors of polymorphonuclear leukocytes in children with atopic dermatitis. Their number and affinity to the radioligand [125I]-cyanopindolol.

[125I]-cyanopindolol (ICYP) was used in a binding assay to compare the number and affinity of beta 2-adrenoceptor binding sites on circulating polymorphonuclear leukocytes (PMN) of 21 children with atopic dermatitis (AD) and 23 age-matched controls. We found no correlation between the beta 2-adrenoceptor density and the age of the children in either collective. Furthermore, the number and affinity of beta 2-adrenoceptor binding sites on PMN was neither influenced by sex nor severity of disease, serum IgE level or percentage of eosinophils in the differential blood count. There was a tendency towards a lower number of beta 2-adrenoceptors in AD subjects (1,429 +/- 587 receptors/PMN) compared to controls (1,753 +/- 596 receptors/PMN), but this difference was statistically not significant.

Adolescent↗
PubMed1991

[House dust mite allergy].

To study efficacy of a purified and biologically standardized house dust mite extract 66 allergic children were investigated. 26 patients on immunotherapy and 21 controls with symptomatic treatment only finished the study. A significant reduction of the skin reactivity associated with an increase of allergen specific IgG-antibodies was observed. However, no significant differences were found correlating the results of inhalative provocation tests, specific IgE antibodies and symptom scores. The immunotherapy with house dust mite extracts needs further evaluation.

Animals↗
PubMed1991

[The special problem of insect venom allergy in childhood].

Natural history of hymenoptera sting allergy is less life threatening in children than in adults. We evaluated a commonly used risk score (allergic reaction to the index sitting, sensitization measured by skin prick test and specific IgE, and specific IgG - maximal 8 points) for its predictability of forthcoming allergic reactions. 93 children with low scores (less than 7 points) experienced stings in field, 96% were save from severe systemic reactions. Of 119 children with high scores (greater than 6 points) receiving rush hyposensitization only 32% developed systemic reactions. We conclude that the score appropriately identifies individuals not to be hyposensitized, but that it overestimates the number of children with a need for hyposensitization. We therefore developed a diagnostic scheme including challenge stings to identify those children who really need hyposensitization.

Adolescent↗
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

[The immunogenicity and allergenicity of an experimental cow's milk protein hydrolysate].

Recently hydrolyzed cow milk proteins have been introduced for the production of infant formulas and are available as hypoallergenic infant formulas. To achieve a decrease in antigenicity and allergenicity a protein hydrolysis (mostly enzymatic) is performed. Sera of different groups were tested for IgG and IgE antibody-binding: 31 controls, 36 atopic children, and 20 children with cow milk protein allergy. Histamine release from basophil leucocytes after incubation with the cow milk proteins beta-lactoglobuline and casein, as with the cow milk protein hydrolysate, was determined additionally for five control, 10 atopic, and five cow milk allergic children. IgG binding to cow milk protein and to the hydrolysate was found in the majority of the sera tested. IgE binding was detectable in sera of only five of the 10 cow milk allergic children, despite detection of specific IgE-antibodies against cow milk proteins in all sera. Histamine release by the cow milk hydrolysate was observed for five atopic and two cow milk allergic children. The cow milk hydrolysate demonstrated a decreased but partially conserved antigenic/allergenic potency compared with cow milk proteins.

Adolescent↗