Estelle Simons

Canadian Pediatric Asthma Consensus Guidelines, 2003 (updated to December 2004): Introduction

Background: Although guidelines for the diagnosis and management of asthma have been published over the last 15 years, there has been little focus on issues relating to asthma in childhood. Since the last revision of the 1999 Canadian asthma consensus report, important new studies, particularly in children, have highlighted the need to incorporate this new information into asthma guidelines. Objectives: To review the literature on asthma published between January 2000 and June 2003 and to evaluate the influence of new evidence on the recommendations made in the Canadian Asthma Consensus Report, 1999 and its 2001 update with a major focus on pediatric issues. Methods: Diagnosis of asthma in young children, prevention strategies, pharmacotherapy, inhalation devices, immunotherapy and asthma education were selected for review by small expert resource groups. In June 2003, the reviews were discussed at a meeting under the auspices of the Canadian Network For Asthma Care and the Canadian Thoracic Society. Data published up to December 2004 were subsequently reviewed by the individual expert resource groups. Results: This report evaluates early life prevention strategies and focuses on treatment of asthma in children. Emphasis is placed on the importance of an early diagnosis and prevention therapy, the benefits of additional therapy and the essential role of asthma education. Conclusion: We generally support previous recommendations and focus on new issues, particularly those relevant to children and their families. This guide for asthma management is based on the best available published data and the opinion of health care professionals including asthma experts and educators.

House dust mite allergen levels in two cities in Canada: effects of season, humidity, city and home characteristics

The homes of 120 patients with asthma, 57 in Vancouver and 63 in Winnipeg, were studied. The characteristics of the homes were assessed by a questionnaire. Dust samples were collected and the indoor relative humidity was measured four times during the year covering all four seasons in both cities. Mite allergen levels were determined using monoclonal antibodies against Der p I and Der f I by the ELISA method. The mean levels of both mite allergens in mattress and floor samples in the homes in Vancouver and in Winnipeg were relatively low for all seasons. Mite allergen levels were found to be associated with city, season and individual home differences. They were significantly higher in Vancouver than in Winnipeg. Der p I and Der f I in mattress samples in both cities and Der f I in floor samples in Vancouver, varied by season. The indoor relative humidity level in the homes in Vancouver were also significantly higher than those in Winnipeg. There was, however, no significant association between the levels of indoor relative humidity and the levels of mite allergens after adjusting for variations in city, season and individual home. Although individual home differences were highly associated with mite allergen levels, only a few home characteristics were found to be related to mite allergen levels such as the type and the age of the home, the type of heating, the use of feather pillows and the number of occupants in the homes. Whether low levels of mite allergens are partially responsible for the relatively low prevalence of childhood asthma in Canada remains to be investigated.

Effect of Application of Benzyl Benzoate on House Dust Mite Allergen Levels

BACKGROUND Several acaricides have become available for reducing house dust mite allergen levels. OBJECTIVE The purpose of this study was to assess whether the use of benzyl benzoate (Acarosan) provides additional benefit to the usual mite control measures including encasement of mattress and pillows with vinyl covers. METHODS A randomized controlled trial was carried out in 26 homes (14 control versus 12 treatment) of asthmatic patients in two cities (Vancouver and Winnipeg). The control group had the usual house dust mite control measures including the use of vinyl covers for mattresses and pillows while the treatment group had application of benzyl benzoate to mattresses and carpets in the bedroom and the most commonly used room, in addition to the above control measures. Mite allergen levels were measured 3 months and immediately before, 1 week, and 1 and 3 months after the application of house dust mite control measures. Patients kept diary cards on asthma symptoms and peak expiratory flow rates morning and evening one month before and three months after the onset of mite allergen control measures. RESULTS A reduction of mite allergen level was found in mattress samples in both groups, statistically significant at all times in the treatment group and at one and three months in the control group. Mite allergen levels on floor carpets also showed progressive reduction in both groups, but were significantly different in the treatment group (compared with controls) at 1 week, and were lower compared with baseline in the treatment group up to 3 months. No significant changes in asthma symptoms, peak expiratory flow rates, spirometric measurements, or bronchial hyperresponsiveness were observed among treatment or control group subjects. CONCLUSION The addition of benzyl benzoate to conventional house dust mite control measures resulted in a significant reduction in floor carpet dust mite levels that persisted for 3 months. The results of this study should be confirmed in a larger and longer study.

Purification and Identification of Polyclonal IgE Antibodies from Ragweed-Sensitized Dog Sera

We have purified and characterized polyclonal dog IgE. Serum IgE was precipitated by (NH4)2SO4 and then purified by two different procedures. Ion exchange on DEAE-Sephacel, followed by HPLC using Tonen hydroxylapatite and then Protein G-Sepharose, produced a highly purified IgE fraction (No. 1) free of IgG, IgA and IgM as measured by ELISA, but recovery of IgE as measured by passive cutaneous anaphylaxis was low. Gel filtration on Sephacryl S-300, Con A-Sepharose and Protein G-Sepharose recovered 18% of initial IgE, 0.02% IgG, 0.4% IgM and 0.3% IgA. This IgE fraction (No. 2) was used to induce antibody production in rabbits. Western blot analysis was then performed for dog IgE fractions No. 1 and 2. Using the rabbit anti-dog IgE, a prominent IgE band with an apparent molecular mass of 226 kD was identified in fractions No. 1 and 2 subjected to nonreducing SDS-PAGE. This band also reacted with anti-human IgE, but not with anti-dog IgG or anti-dog IgA. Under reducing conditions the approximate molecular mass for the IgE & chain, estimated by Western blot using rabbit anti-dog IgE, was 73 kD, providing a molecular mass of 196 kD for dog IgE.

Quantification of Human Chemokine Production in TLR-Stimulated and Antigen-Specific Recall Responses

Chemokines are primarily low molecular mass proteins that are produced and usually released by a wide variety of cell types. Differential chemokine responses can be excellent early markers of immune dysfunction, allowing clinical intervention prior to expression of full blown undesirable effector responses. Thus, assessment of the nature and intensity of Ag-dependent chemokine production provides a valuable tool for probing human immune regulation.Here, we provide detailed instructions on approaches we have developed to assess the nature and intensity of recall responses to a wide variety of exogenous and endogenous antigens capable of consistently stimulating chemokine responses by PBMC from adult and pediatric populations. This chapter is divided into two sections. The first is focused on culture techniques for eliciting antigen-driven chemokine responses for a panel of chemokines that are relevant to immune function. The second section details assay systems for their quantitative analysis.

Inhaled salbutamol (Albuterol) vs injected epinephrine in the treatment of acute asthma in children

In a double-blind trial we compared the efficacy and safety of inhaled salbutamol (albuterol), nebulized with oxygen by face mask, and subcutaneous epinephrine in 40 children with acute asthma. No significant difference between salbutamol and epinephrine was seen at any time for clinical score, respiratory rate, heart rate, blood pressure. PaO2, PaCO2, FVC, FEV1, FEV1/FVC, or FEF25-75%. PaO2 remained unchanged after salbutamol but increased significantly (P less than 0.05) after epinephrine. No significant difference occurred between the groups for repeat treatment, admission on initial visit, return to emergency room, admission on return, or total admissions. Significantly (P less than 0.01) increased adverse effects were seen within the group given epinephrine. We conclude that inhaled nebulized salbutamol and subcutaneous epinephrine are equally effective. In view of the lack of adverse effects and noninvasiveness of inhaled salbutamol, we recommend its use for the treatment of acute asthma in children.