Irvin Broder

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.

Correlation between nasal symptoms and asthma severity in patients with atopic and nonatopic asthma

BACKGROUND The association between allergic rhinitis and asthma has been well recognized, and it has been postulated that rhinitis may worsen asthma. OBJECTIVE To investigate the severity of asthma among patients with atopic and nonatopic asthma with and without nasal symptoms. METHODS Atopic asthmatic patients and nonatopic asthmatic patients were identified from the records of a university-based asthma clinic. A comparison of demographic clinical features was made within and between these 2 asthmatic groups, dichotomized according to the presence or absence of rhinitis. RESULTS A total of 178 patients were classified as having atopic asthma and 218 as having nonatopic asthma. The atopic asthmatic patients with nasal symptoms compared with those without had a higher mean forced expiratory volume in 1 second (FEV1), a higher forced vital capacity (FVC), and a higher FEV1/FVC ratio, used fewer oral steroids, and had fewer hospitalizations. The nonatopic asthmatic patients with nasal symptoms compared with those without used more inhaled steroids (and they were also more likely to have nasal polyps on examination). Atopic, relative to nonatopic, asthmatic patients were younger, had a longer duration of asthma, had a higher FEV1/FVC ratio, and took fewer oral steroids. CONCLUSION Contrary to current hypotheses, in this study the severity of asthma among atopic asthmatic patients was less in those with nasal symptoms. Conversely, among the nonatopic asthmatic patients, asthma was more severe among those with nasal symptoms than those without nasal symptoms.

Severity of asthma in skin test-negative and skin test-positive patients

The standardized records of 144 asthmatic patients have been analyzed to determine whether the severity of their condition was correlated with the presence or absence of positive intradermal skin test reactions to a panel of seven allergen extracts (dust, feathers, Alternaria, Hormodendrum, mixed tree pollen, mixed grass pollen, and ragweed pollen). The skin tests were totally negative in 71 of the subjects, whereas in 73 subjects there was a strongly positive response to two or more allergens. The skin test-negative patients were older than the skin test-positive ones and had a shorter duration as well as a later onset of asthma. Also, they had lower serum-IgE levels and a lower frequency of a family history of atopic disease. Moreover, the skin test-negative group lost more time from their normal activities, required more visits to their doctor as a result of asthma, and were more frequently treated with oral corticosteroids. They additionally had greater air trapping on pulmonary function tests. However, when the groups were adjusted for the discordance in their age and duration of asthma, they tended to converge in the level of the variables that described the severity of their asthma. Thus the severity of asthma was found to be relatively similar in skin test-negative and skin test-positive patients.

Tartrazine and benzoate challenge and dietary avoidance in chronic asthma

This study undertook to determine the usefulness of tartrazine and benzoate challenge and dietary avoidance in the management of patients with chronic asthma. Double‐blind ingestion‐challenge tests were performed on separate days with lactose, tartrazine, benzoate and acetylsalicyclic acid (ASA). Of the twenty‐eight subjects challenged, one responded to tartrazine and one to benzoate. Two additional subjects responded to ASA and a further eight were not tested with this material because of a definite history of sensitivity. Twenty‐four subjects completed 1 month periods of observation while first on a normal diet and then while on a tartrazine‐benzoate avoidance diet. No improvement occurred during the modified diet in anyone with positive challenge‐tests or in all, but one, of those with a history of ASA idiosyncrasy; paradoxically, several of these subjects worsened during this period. We conclude that tartrazine‐benzoate dietary avoidance was not of value in the management of the chronic asthmatic in this study, even among patients who respond to challenge with these substances or have ASA idiosyncracy.

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam: II. Initial health and house variables and exposure-response relationships

A health survey was conducted on 1726 occupants of urea formaldehyde foam insulated (UFFI) houses and 720 residents of control homes. The occupants of the UFFI houses showed a modest excess of many symptoms relative to the controls. This excess of complaints was contributed mainly by the residents of households which were intending to have their UFFI removed and by onsets which followed the installation of UFFI. There were no associated abnormalities in nasal airway resistance, sense of smell, pulmonary function, or patch tests for allergy to formaldehyde. However, the UFFI subjects intending to have their UFFI removed demonstrated a small increase in nasal epithelial squamous metaplasia. The indoor formaldehyde levels of the UFFI houses were about 20% higher than in the controls, while the carbon dioxide levels were similar in both groups. The UFFI subjects showed positive relationships between level of formaldehyde exposure and the presence of a number of symptoms, which were largely dependent on a small group of formaldehyde values that were in excess of 0.12 ppm. A number of the exposure-response relationships were enhanced by UFFI. These results suggested that some adverse health effects of UFFI were explained by formaldehyde alone while others were related to the combined effects of formaldehyde and an additional UFFI-related factor(s) which was not identified.

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam. I. Methodology

The methodology of a study in which a comparison is made of the health and house characteristics of the occupants of 231 control homes and 571 houses containing urea formaldehyde foam insulation (UFFI) is described. All homes and occupants were examined on two occasions separated by an interval of 12 months, during which two-thirds of the UFFI houses performed remedial work. The occupants were examined using a health questionnaire and a series of objective tests including pulmonary function, nasal airway resistance, sense of smell, nasal surface cytology, and patch tests. The houses were assessed using a questionnaire and measurements of indoor formaldehyde and carbon dioxide levels. No obvious bias has been identified in this survey with respect to the representativeness of the population studied, the classification of the UFFI and control groups, and the input from both the respondents and observers. The symptom responses made by individuals within the same households were not correlated. Quality control assessment of the objective health tests and formaldehyde sampling and assays demonstrated that these procedures remained stable over the two phases of the study, with the exception of the expected decrease in the pulmonary flow rates over 1 year and a small unexpected increase in the forced vital capacity and the forced expiratory volume in 1 s.

Personal Exposure of Adults with Cardiorespiratory Disease to Particulate Acid and Sulfate in Saint John, New Brunswick, Canada

Abstract Saint John is the site of an ongoing study of the relationship between cardiorespiratory emergency department visits and airborne particles, including particulate acid and sulfate. The purpose of the present study was to assess the extent to which fixed site monitors reflect average personal exposure to fine particle sulfate and acidity among adults visiting the emergency department with cardiorespiratory disease. Study participants had made an emergency department visit for cardiorespiratory disease in the previous 12 months and resided within approximately 5 km of the fixed site monitor which records the highest sulfate and acid concentrations in Saint John. Twenty-one volunteers wore personal annular denuders during the period from 7 a.m. to 6 p.m. (mean duration 7.6 hours) for up to four separate days between July 6 and August 11, 1995, and completed a time-activity diary for each sampling period. Subjects ranging from 49 to 85 years of age completed a total of 62 sampling periods. The mean p...

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam. III. Health and house variables following remedial work.

This report describes the second survey of a group of 762 control and urea formaldehyde foam insulated (UFFI) houses performed following an interval of 1 year, after about two-thirds of the UFFI households either had their UFFI removed or performed other UFFI-related remedial work. The UFFI subjects who lived in remedial houses showed a decline in indicators of impaired health status, to roughly equalize with those whose houses were not altered; they continued to show a small excess of adverse health indicators relative to the controls, but at a somewhat lower level than seen in the first survey. This improvement was not associated with changes in indoor levels of formaldehyde. Weak exposure-response relationships were observed between formaldehyde and upper and lower respiratory symptoms, but mainly in the combined UFFI and control populations; these are interpreted as representing the contribution of background levels of formaldehyde to the prevalence of respiratory complaints in the general population. The principal findings of this study were primarily based on subjective variables, but most could be directly validated by objective measurements in the UFFI and control subjects. The support for a causal relationship between impaired health and living in a UFFI house is considered to be moderately strong. However the demonstrated adverse effects are generally minor in nature.

Grain dust contains a tannin-like material which fixes complement

Grain dust extract has been found to activate complement. We investigated the possibility that this activity was due to tannin by comparing the characteristics of grain dust extract with those of tannic acid. The properties that were studied were the interaction with albumin and immunoglobulin G, the stability to heat, and the adsorption to polyvinylpolypyrrolidone and hide powder. Grain dust extract was found to show similarities with tannic acid which were consistent with the presence of tannin accounting for most of its complement fixing activity.

Phenol amplifies complement-fixing activity and induces IgG-precipitating activity in grain-dust extract

The use of phenol as a preservative in extracts of grain dust was found to be associated with an amplification of complement-fixing activity and the appearance of IgG-precipitating activity. Both activities were absorbed by IgG, suggesting that they were due to a single material. Phenol itself neither fixed complement nor formed a precipitate with IgG. 14C-labeled phenol was incorporated into the IgG precipitating material. Both the amplification of complement-fixing activity and the appearance of IgG-precipitating activity in phenol-containing grain-dust extract were dependent on the presence of air and were inhibited by heating the extract before phenol addition. One interpretation of these results is that a component of grain-dust extract, possibly an enzyme, oxidatively modifies phenol to a form that fixes complement and precipitates IgG. The modified material demonstrates properties of a polyphenol (tannin).