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Biomedical subjects

H A Burge

Publications and source records attributed to H A Burge.

At least 19 recordsLinked to original sources
PubMed2000

Dynamics of airborne fungal populations in a large office building.

The increasing concern with bioaerosols in large office buildings prompted this prospective study of airborne fungal concentrations in a newly constructed building on the Gulf coast. We collected volumetric culture plate air samples on 14 occasions over the 18-month period immediately following building occupancy. On each sampling occasion, we collected duplicate samples from three sites on three floors of this six-story building, and an outdoor sample. Fungal concentrations indoors were consistently below those outdoors, and no sample clearly indicated fungal contamination in the building, although visible growth appeared in the ventilation system during the course of the study. We conclude that modern mechanically ventilated buildings prevent the intrusion of most of the outdoor fungal aerosol, and that even relatively extensive air sampling protocols may not sufficiently document the microbial status of buildings.

Air Conditioning↗
PubMed1999

Monthly measurements of indoor allergens and the influence of housing type in a northeastern US city.

BACKGROUND: We examined seasonal variation of dust-mite (Der f 1 and Der p 1), cat (Fel d 1), and cockroach (Bla g 1) allergens in Boston, while adjusting for other covariates. Limited data are available on seasonal patterns of indoor allergen concentrations for different geographic regions in the USA. Understanding within-home seasonal variation of allergens is important epidemiologically and clinically. METHODS: From June 1995 to June 1996, dust samples were vacuumed monthly from the bed, bedroom floor, and kitchen of 20 homes. Indoor temperatures were measured monthly and used in calculating relative and absolute humidity. Monthly home characteristics questionnaires were completed by an adult resident of each home. Dust samples were assayed by enzyme-linked immunosorbent assays. RESULTS: Der f 1 and Der p 1 in beds and floors peaked in the autumn months, Fel d 1 peaked in winter and spring, and Bla g 1 was highest in summer. Dust-mite allergen concentrations were 1.9-2.4 times higher in autumn than spring, but the levels in beds were 19-31 times higher in houses than those in apartments. Although Fel d 1 levels in beds were 2.4 times higher in spring than summer, homes with cats had levels 224 times higher than those without cats. Similarly, Bla g 1 levels in kitchens were 2.1 times higher in summer than winter, but apartments had levels five times higher than those of houses. CONCLUSIONS: Sampling season is a source of within-home dust-mite, cat, and cockroach allergen variation in the northeastern USA. However, the influence of housing type and owning a cat far outweighed the seasonal variation of these indoor allergens.

Adult↗
PubMed1999

The effects of carpet fresheners and other additives on the behaviour of indoor allergen assays.

BACKGROUND: Chemical agents such as tannic acid and detergents have been shown to introduce non-random bias in allergen measurement. OBJECTIVE: We investigated how several substances that are commonly found in floor dust (carpet fresheners, powdered pesticides, and table salt) affected immunoassays of purified standard allergens. METHODS: Three sets of experiments were conducted to: (1) screen for interference with allergen enzyme-linked immunosorbent assay (ELISA); (2) test for concentration-response; and (3) assess the site-of-action of a given dust additive (i.e. the effect on allergen binding to primary or secondary antibody). The ELISAs are commercially available two-site monoclonal antibody assays for Der p 1, Der f 1, and Fel d 1, and a monoclonal/polyclonal assay for Bla g 1. Outcomes are reported in terms of reaction rate (colour change per unit time), which is directly proportional to the amount of bound allergen. RESULTS: In the initial screening experiments, carpet fresheners tended to decrease Der p 1 assay reaction rates, increase Der f 1 assay rates, and produce little change in Fel d 1 assay rates. Three carpet fresheners decreased Der p 1 assay rate responses in a concentration-dependent manner. Two carpet fresheners noticeably increased Der f 1 assay reaction rates in both the screening and the concentration-response tests. Powdered pesticides increased reaction rates in the Bla g 1 assays and increased the slope of the dilution curve compared with that of the purified allergen. Salt decreased the reaction rates of Bla g 1 assays at allergen concentrations greater than 0.01 U/mL. For each of the four allergens, the largest effects of dust additives occurred when secondary antibody binding was altered. CONCLUSIONS: Some common household dust components can introduce systematic error into immunoassays for arthropod allergens.

Allergens↗
PubMed1999

Predictors of repeated wheeze in the first year of life: the relative roles of cockroach, birth weight, acute lower respiratory illness, and maternal smoking.

While more than 80% of childhood asthmatics are allergic to one or more inhaled allergens, the role of inhaled allergens in the induction of wheeze in the first year of life is unknown. In a prospective birth-cohort study of 499 children of asthmatic/allergic parents from metropolitan Boston, we examined home allergen concentrations measured within the first 3 mo of life as predictors of repeated wheeze episodes in the first year of life. In multivariate analyses adjusting for maternal asthma and dog in the home, predictors of two or more wheeze episodes in the first year of life included maternal smoking during pregnancy (relative risk [RR] = 1.83; 95% confidence limit [CL]: 1.12, 3.00), lower respiratory illness in the first year of life (croup, bronchitis, bronchiolitis, or pneumonia) (RR = 2.25; 95% CL:1.58, 3.19), low birthweight (RR = 1.28, 95% confidence interval [CI]: 1.04, 1.58 for an interquartile difference), and Bla g 1 or 2 (cockroach) allergen level in the family room > 0.05 U/g dust (RR = 1.76; 95% CL: 1.20, 2.57). Cockroach allergen in the family room and repeated wheeze remained significant after adjustment for socioeconomic factors including race and income (RR = 1.63; 95% CL: 1.05, 2.55). It is unknown whether the association between cockroach and repeated wheeze in infancy represents a cockroach-related increased risk of bronchial inflammation through nonallergenic or allergenic mechanisms.

Allergens↗
PubMed1998

Limitations of a home characteristics questionnaire as a predictor of indoor allergen levels.

We examined associations between reported home characteristics and levels of indoor allergens in 499 homes of a birth cohort of children of allergic/asthmatic families from the Boston area. The risk of having dust mite allergen (Der f 1 or Der p 1) > or = 2 microg/g on the bedroom floor was highest in houses, but 16% of apartments had levels this high. Compared with that from smooth floors, dust from carpeted bedroom floors had 2.1 times the risk of dust mite allergen > or = 10 microg/g, but levels exceeded 2 microg/g in 32% of uncarpeted floors. The risk of dust mite allergen > or = 10 microg/g of dust from plastic-encased mattresses was 0.5 times that for cloth mattresses, but levels in 21% of plastic-encased mattresses were > or = 2 microg/g. In 93% of homes with and 3% of homes without cats, Fel d 1 was > or = 8 microg/g, but 34% of homes without cats had Fed d 1 > or = 1 microg/g. Cockroach allergen (Bla g 1 or Bla g 2) was > or = 2 U/g of kitchen dust in 26% of apartments and only 6% of houses, and it was detected in 48% of homes with no reported signs of cockroaches in the previous 12 mo. Home characteristics reporting is a relatively weak predictor of the absence of allergen, and exposure can occur even when no cats are present, beds are encased in plastic, no carpets are present, and no signs of cockroaches have been reported.

Air Pollution, Indoor↗
PubMed1998

Parental history and the risk for childhood asthma. Does mother confer more risk than father?

Although heredity plays a major role in asthma and in other allergic diseases, mechanisms underlying the inheritance of these disorders are poorly understood, as is the relative contribution of maternal and paternal conditions to risk of disease. We investigated doctor-diagnosed maternal and paternal asthma, eczema, and hay fever as cross-sectional predictors of childhood asthma and allergic disease in 306 children with a median age of 3.5 yr from families in which at least one parent had a history of either asthma or other allergic conditions. For both childhood asthma and eczema, the strongest parental predictors were the same conditions in the parents. For asthma in particular, maternal asthma was most strongly associated with asthma in the child over all ages in both univariate (OR = 3.2, 95% CI = 1.5 to 6.7) and multivariable (OR = 4.1, 95% CI = 1.7 to 10.1) models. Paternal asthma was weakly associated with childhood asthma in the univariate model (OR = 1.4, 95% CI = 0.6 to 3.2), but this association increased in magnitude in the multivariable model (OR = 2.7, 95% CI = 1.0 to 7.2). Among the children < 5 yr of age, the risk for childhood asthma associated with maternal asthma (OR = 5.0, 95% CI = 1.7 to 14.9) was greater than the risk associated with paternal asthma (OR = 1.6, 95% CI = 0. 5 to 5.9), whereas both maternal asthma and paternal asthma were associated with similar risks among children >= 5 yr of age (OR = 4. 6, 95% CI = 1.1 to 19.0 and OR = 4.1, 95% CI = 1.0 to 16.0, respectively). The odds of having a child with asthma were three times greater in families with one asthmatic parent and six times greater in families with two asthmatic parents than in families where only one parent had inhalant allergy without asthma; furthermore, inhalant allergy in one parent also conferred additional risk in the presence of asthma in the other parent. Further investigation is needed into the relative importance of genetic factors and in utero and postnatal exposures in determining the differential effects of maternal and paternal asthma on the development of childhood asthma.

Adult↗
PubMed1997

Health risk assessment of fungi in home environments.

LEARNING OBJECTIVES: Reading this article will enable the readers to recognize the public health importance of fungi in the home environment. In view of the recognized impact of fungi on human health, the large population being exposed to fungi, and the large population risk for developing allergic diseases, there is a need to establish guidelines for allowable exposure to fungi based on a health risk assessment. The aim of this study was to evaluate the status of the data on the relationship between exposure to fungi in the home environment and allergic health effects with respect to the development of such guidelines. DATA SOURCES: The past 10 years of peer-reviewed literature focused on the relationships between respiratory disease and exposure to fungi in indoor environments was examined, Indexing terms included mold, fungi, allergy, asthma, and indoor environment, among others. Each study was evaluated on the following criteria: aim and design of the study, methods for assessing exposure and health effects, and data analysis. STUDY SELECTION: Nine population based studies were identified that examined the relationship between allergy and the presence of fungi in the home environment. These studies included quantitative measures of fungal presence in either air or dust. RESULTS: One or more positive associations were found between fungal levels and health outcomes in seven of the nine cross-sectional studies identified. CONCLUSIONS: Despite these positive associations it remains impossible to set guidelines for fungi in home environments based on health risk assessment. This is in part because of the cross-sectional study designs, and inconsistency and inadequate validation of the measures used to evaluate exposure and health effects. Future research designed to generate data that can be used for the development of health risk assessment based guidelines for fungi in home environments should focus on susceptible populations, and use measures that accurately represent exposure and adverse health effects.

Air Microbiology↗
PubMed1996

Review of quantitative standards and guidelines for fungi in indoor air.

Existing quantitative standards/guidelines for fungi in indoor air issued by governmental agencies are based primarily on baseline data (rather than health effects data), and are either absolute (numerical) or relative (indoor/outdoor comparisons) or a combination of the two. The Russian Federation is the only governmental agency that has binding quantitative regulations for bioaerosols. Recommended guidelines have been proposed or sponsored by North American and European governmental agencies and private professional organizations. A considerable number of frequently cited guidelines have been proposed by individuals based either on baseline data or on personal experience. Quantitative standards/guidelines range from less than 100 CFU/m3 to greater than 1000 CFU/m3 (total fungi) as the upper limit for non-contaminated indoor environments. Major issues with existing quantitative standards and guidelines are the lack of connection to human dose/response data, reliance on short term grab samples analyzed only by culture, and the absence of standardized protocols for data collection, analysis, and interpretation. Urgent research needs include the study of human responses to specific fungal agents, development and widespread use of standard protocols using currently available sampling methodologies, and the development of long term, time-discriminating personal samplers that are inexpensive, easy to use, and amenable to straightforward, relevant analysis.

Air Microbiology↗
PubMed1992

Examination of fungi in domestic interiors by using factor analysis: correlations and associations with home factors.

Factor analysis was utilized to investigate correlations among airborne microorganisms collected with Andersen samplers from homes in Topeka, Kans., during the winter of 1987 to 1988. The factors derived were used to relate microbial concentrations with categorical, questionnaire-derived descriptions of housing conditions. This approach successfully identified groups of common aboveground decay fungi including Cladosporium, Alternaria, Epicoccum, and Aureobasidium spp. The common soil fungi Aspergillus and Penicillium spp. were also separated as a group. These previously known ecological groupings were confirmed with air sampling data by a quantitative evaluation technique. The aboveground decay fungi sampled indoors in winter were present at relatively high concentrations in homes with gas stoves for cooking, suggesting a possible association between these fungi and increased humidity from the combustion process. Elevated concentrations of the soil fungi were significantly (P = 0.05) associated with the dirt floor, crawl-space type of basement. Elevated concentrations of water-requiring fungi, such as Fusarium spp., were shown to be associated with water collection in domestic interiors. Also, elevated mean concentrations for the group of fungi including Cladosporium, Epicoccum, Aureobasidium, and yeast spp. were found to be associated (P = 0.03) with symptoms reported on a health questionnaire. This finding was consistent with our previous study of associations between respiratory health and airborne microorganisms by univariate logistic regression analysis.

Air Microbiology↗
PubMed1992

Monitoring for airborne allergens.

Monitoring for allergens can provide some information on the kinds and levels of exposure experienced by local patient populations, providing volumetric methods are used for sample collection and analysis is accurate and consistent. Such data can also be used to develop standards for the specific environment and to begin to develop predictive models. Comparing outdoor allergen aerosols between different monitoring sites requires identical collection and analysis methods and some kind of rational standard, whether arbitrary, or based on recognized health effects.

Air Pollution↗
PubMed1991

Particle penetration into the automotive interior. I. Influence of vehicle speed and ventilatory mode.

Penetration of particulate aeroallergens into the interiors of two, new, similar Chrysler Corporation passenger vehicles (having no evidence of intrinsic microbial contamination) was studied on a large circular test track during periods of high pollen and spore prevalence. Impactor collections were obtained at front and rear seat points and at the track center during periods with (1) windows and vents closed and air conditioning on, (2) windows closed, vents open, and no air conditioning, and (3) air conditioner off, front windows open, and vents closed. These conditions were examined sequentially during travel at 40, 50, 60, and 80 kph. Particle recoveries within the two, new, similar Chrysler Corporation passenger vehicles did not vary with the speed of travel, either overall or with regard to each of the three ventilatory modalities. In addition, collections at front and rear seat sampling points were comparable. Highest interior aeroallergen levels were recorded with WO, and yet, these levels averaged only half the concurrent outside concentrations at track center. Recoveries within the cars were well below recoveries obtained outside when windows were closed (both VO and AC modes). These findings suggest window ventilation as an overriding factor determining particle ingress into moving vehicles. Efforts to delineate additional determinants of exposure by direct sampling are feasible and would appear essential in formulating realistic strategies of avoidance.

Aerosols↗