Prevention of Postinfectious Asthma in Children by Reducing Self-Inoculatory Behavior

Recent studies have shown that the spread of infectious nasalsecretions from hand-to-hand or hand-to-object, followed byself-inoculation is an efficient means of viral transmission.The present study was designed to investigate whether self-inoculationbehavior in asthmatic children could be reduced and, if so,whether this reduction would reduce the frequency of infectionand asthma. Sixteen subjects aged 4 to 8, all diagnosed withpostinfectious asthma, were assigned to a treatment (differentialreinforcement of other behavior and contingent education) orplacebo control condition. Results indicate that self-inoculatorybehavior, infection, and asthma were signjficantly reduced.These findings may indicate an important role for behavioralmedicine inpostinfectious asthma.     

Relationships between Responsiveness of the Bronchi to Acetylcholine and Cyclic AMP Response of Lymphocytes to Beta1- and Beta2-Adrenergic Receptor Stimulation in Patients with Asthma

Decreased response of beta-adrenergic receptor has been considered to he one of the causes of increased responsiveness of the bronchi in asthma. Since beta-adrenergic receptor has two subtypes, beta₁ and beta₂, and the bronchodilating effect of beta stimulants is mediated by beta₂-receptor, responsiveness of the bronchi is expected to correlate to the cyclic AMP response of lymphocytes to a beta₂-stimulant. Responsiveness of the bronchi was expressed as respiratory threshold to acetylcholine (RT-Ach), which was the minimal concentration of acetylcholine solution to cause an initial decrease of FEV₁ of more than 20% of the baseline value. Beta₁ and heta₂-responses were expressed as the increments of cyclic AMP content of 10⁶ lymphocytes incubated with norepinephrine (beta₁-stimulant) and salbutamol (beta₂-stimulant).
RT-Ach showed a significant correlation with the beta₂-cyclic AMP response of lymphocytes, but not with the beta₁ -response among patients with asthma. Sixteen symptomatic patients on continuous beta-stimulants showed lower RT-Ach value and diminished beta₂-receptor activity of lymphocytes compared with 14 patients in remission. These results suggest that selective beta₂-adrenergic blockade may he one of the causes of bronchial hypersensitivity in asthma, though it should be noted that in this study beta-adrenergic responses were examined in lymphocytes and were compared with the responsiveneness of the bronchi. Possible beta-receptor subsensitivity induced by administration of beta-stimulants is discussed.     

The effect of intravenously administered salbutamol on serum potassium in asthmatic and nonasthmatic atopic subjects

The role of adrenergic mechanism in the pathogenesis of allergic disease is controversial. Recent experimental and clinical reports have suggested that -adrenergic blockade impairs and stimulation enhances extrarenal potassium uptake in humans. This led us to study the effect of the intravenous administration of salbutamol, a specific -2-adrenergic agonist, on serum potassium in 9 healthy subjects and in 23 patients with allergic asthma and/or rhinitis. Serum potassium fell significantly and reached a peak decline at the end of venous infusion in all the normal subjects. Seventeen atopic subjects showed a lower or absent serum K⁺ decrement: there was no difference between asthmatic and rhinitic patients. There was no relation among the salbutamol-induced serum potassium decrement, serum glucose increment, blood pressure and heart-rate changes, and nonspecific bronchial reactivity. These findings suggest that -2-adrenergic hyporesponsiveness is present only in some allergic patients.     

Priming effect of RANTES on eosinophil oxidative metabolism

Background RANTES has been shown to possess chemotactic activity for eosinophils, which have also been considered to play a role in allergic inflammation through reactive oxygen species. Thus, in this study, we examined the effect of RANTES on radical oxygen products from eosinophils.
Methods Purified eosinophils by CD16-negative selection or an eosinophilic cell line (EoL-1) were incubated with or without RANTES (2.5 x 10⁻⁶). To the mixture of eosinophils and luminol, calcium ionophore (A23187) or opsonized zymosan (OZ) was added, and radical oxygen products were determined by luminol-dependent chemiluminescence for 600 s.
Results Eosinophil-mediated radical oxygen products of untreated eosinophils produced with A23187 gave a peak value of 14.09 + 2.40 (mean±SE, n = 12) relative light units (RLU) and an integrated value of 3232.20 + 513.09 RLU. However, with treatment with RANTES, a peak value of 18.66 + 2.40 RLU and an integrated value of 5301.05 ±561.02 RLU were obtained. Eosinophil oxidative metabolism-induced A23187 or OZ was apparently augmented by the preincubation with RANTES. In addition, the radical oxygen products of EoL-1 showed similar results.
Conclusions Thus, we concluded that RANTES may play an important role the pathogenesis of allergic inflammation through its involvement in eosinophil activation, as evidenced by oxygen products, as well as in selective eosinophil infiltration as selective eosinophil chemoattractant.     

Prevention of work‐related airway allergies; summary of the advice from the Health Council of the Netherlands

The Health Council of the Netherlands published a report in which the best procedure and method for recommending health‐based occupational exposure limits (OELs) for inhaled allergens were identified by evaluating the scientific state of the art. Many respiratory disorders in the workplace arise from inhalation of substances which can cause allergy. To protect workers against respiratory allergy, various preventive measures are taken, one of them being reduction of exposure by setting legally binding standards. These are based on health‐based OELs that specify a level of exposure to an airborne substance, a threshold level, below which it may reasonably be expected that there is no risk of adverse health effects. The Council is of the opinion that an OEL should prevent against allergic sensitization, as sensitization plays a crucial biological role and is a prerequisite for the development of allergy. Furthermore, the Council considers it most likely that the exposure level below which no allergic sensitization develops for most allergens is so low, that OELs are difficult to set with the current knowledge and technical feasibilities. An alternative approach is to accept exposure, which carries a small predefined risk in developing allergic sensitization. In addition, it is worth considering periodic screening of exposed workers on allergic sensitization, because timely intervention can prevent worse. The feasibility of periodic screening and what else is needed to comply with the most important criteria, should however be judged case‐by‐case.     

Immunotherapy in patients allergic to cat and dog dander

Twenty-four asthmatics allergic to cat and/or dog dander were included in a study to examine the efficacy and safety of immunotherapy (IT) with partially purified, standardized extracts of cat or dog dander. In the first placebo controlled, double-blind part of the study, 10 patients were treated with extracts of both cat and dog, 12 with cat extracts and 2 with dog extracts. Fifteen patients received active IT and 9 placebo injections. Patients treated with both extracts received active extracts only, or placebo only. Bronchial allergen challenge after 5 months demonstrated a significant fall in sensitivity to cat (P = 0.04) in patients treated with cat extracts. No significant changes were found in sensitivity to dog after treatment with dog dander extract or in the placebo groups. During this period, bronchial sensitivity to histamine did not change significantly in any of the groups. To examine the effect of more prolonged IT, 19 patients allergic to cat (17) and/or dog (9) were treated for 12 months. Bronchial sensitivity to cat decreased further (P = 0.003), while no significant change was found in dog extract-treated patients. In cat extract-treated patients a significant decrease in bronchial histamine sensitivity developed (P = 0.02). Systemic side effects were few, but in some cases, local side effects were a dose-limiting factor. This study demonstrated that IT with cat extract may benefit cat-allergic asthmatics, whereas no influence of IT with dog extract was detected in dog-sensitive asthmatics.     

Immunotherapy of tree pollen allergy with a modified alginate conjugated birch pollen extract compared to an aluminium adsorbed extract

The safety and efficacy of two birch pollen extracts, one chemically conjugated to alginate (Anjuvac) the other adsorbed to aluminium hydroxide (Alutard), were investigated in an open multicentre comparative study of 63 birch pollen allergic patients. Both extracts decreased the nasal symptoms during the birch pollen season. The changes in specific IgE and IgG were much the same in both treatment groups. The adverse reactions recorded were mild in both groups, but more frequent in the Anjuvac group, probably because of a more aggressive dose schedule though there were twice as many asthmatics in the Anjuvac group. The two investigated allergen extracts were useful alternatives for immunotherapy.     

Programming life histories: Effects of maternal and environmental variables upon open-field behavior

Open-field behavior was studied as a function of three classes of variables: maternal characteristics, rearing environment, and sexual experience. Mothers of experimental subjects were either handled or nonhandled in infancy. Subjects were born and reared to weaning either in maternit cages or in Hebb-type free environments and were placed after weaning into either a laboratory cage or free enviroment. Sexual experience consisted either of bearing and raising a litter or no sexual experience. The results confirmed previous findings that offspring of mothers handled in infancy arc significantly less active in the open field than the offspring of nonhandled mothers. The maternal handling variable also interacted significantly with breeding experience: for rats which had not been bred, those raised by nonhandled mothers were more active than those raised by handled mothers; for females with breeding experience the reverse was true. Overall, thosc femalcs which had reared a litter were more active and defecated more than their nonbred littermates.     

Sensitization and lung function in workers occupationally exposed to natural thickening products

BACKGROUND: Three workers engaged in the manufacture of natural thickener products (Cassia spp., guar, and tamarind flour) were occupationally sensitized to Cassia spp. Therefore, a cross-sectional study on the prevalence of sensitization among and respiratory health of the employees of this plant was conducted. METHODS AND RESULTS: Sixty-two workers (36 with high, 26 with low exposure) participated in the survey. Skin prick tests and specific IgE tests with extracts of these components revealed that 11.3% were sensitized to Cassia spp. and 9.7% to at least one species of storage mites, with a significantly higher portion of atopic subjects in the sensitized group. Overall, 55% of the subjects reported work-related symptoms (upper and lower airways, eyes, or skin). FVC % pred. was significantly lower in highly exposed workers, while RV % pred. and RV%TLC % pred. were significantly higher in this group. In the multivariate model, sensitization was not a risk factor for impairment of lung function. CONCLUSIONS: Dust exposure to flours may not only cause allergic sensitization but also induce chronic changes in lung function.