Harriet A. Burge

Allergen carriage by atmospheric aerosol. I. Ragweed pollen determinants in smaller micronic fractions.

Outdoor air-bearing natural ragweed pollen burdens were drawn through 5 microns membrane filters during 24 hr periods; aerosols penetrating these barriers were collected on individual, in-line, 0.8 microns filters. The 0.8 microns filters were free of intact pollen grains and grain fragments when scanned in toto by transmitted light. Aqueous extracts of 0.8 microns filters were found to elicit wheal-and-flare skin test reactions in a ragweed pollen-sensitive subject but not in nonatopic controls. The same extracts produced significant inhibition of an IgG-ELISA system by use of ragweed pollen protein conjugated to polystyrene plate wells and pooled serum of patients on ragweed immunotherapy. No inhibition resulted from preincubation of serum with an unrelated allergen (hickory pollen extract). These data indicate the presence of airborne ragweed pollen allergen in aerosol fractions below 5 microns during seasonal periods of ragweed pollination, confirming the report of Busse et al. Potential sources of such aerosols are prominent in nature, and their occurrence may help explain existing dose-response disparities in pollinosis.

Sampling and analysis of biological aerosols

Abstract The extreme particle size range and enormous heterogeneity of airborne biological particles make sampling a significant challenge. Three major sampler types available include gravity devices, impactors and suction samplers. Gravity methods, while most commonly used, are neither qualitatively or quantitatively accurate and of very limited use. Impaction samplers (rotating, centrifugal) accelerate air by rotating the collecting surface or with a fan. Particles are collected from measured volumes of air but these devices preferentially sample particles larger than 10 μm. Suction samplers, which efficiently collect particles of a wide size range from measured volumes of air, include slit samplers, cascade impactors, filtration devices and liquid impingers. Suction samplers can retrieve viable particles by direct impaction on culture media, or by subsequent culture of impinger fluid or filter eluates. Nonviable particles can often be identified by microscopic examination of slides, filters or filtrates of impinger fluids. Immunoassays and biochemical assays can be used with impinger fluid and filter eluates to assess antigen and toxin levels in measured air samples.

Some comments on the aerobiology of fungus spores

Abstract While exposure/symptom relationships are relatively well-defined for pollen allergens, such relationships have not been clearly established for airborne fungus spores due to a lack of clearly defined seasonal patterns, prevalence of world-wide cosmopolitan fungi, and serious problems with sampling and identification. Ascospores and basidiospores have been least studied with respect to aerobiology, although both are clearly allergenic. Preliminary data on allergenicity and diurnal and seasonal prevalence patterns for selected ascospore and basidiospore types are presented.

Evaluation of indoor plantings as allergen exposure sources

The role of indoor plantings as allergen sources was assessed by direct sampling of interior air. Homes with 10 or more plants in one room and three University of Michigan greenhouses were studied by means of a dc-powered rotorod and separate Andersen viable sampler collections incubated at 23 degrees and 50 degrees C. Sequential 30 and 60 sec Andersen samples were obtained during 15 min rotorod collections before and during watering of plants as well as during disturbance of foliage by a small fan. Relative humidity averaged 51% in homes and 78% in greenhouses. Aspergillus fumigatus recoveries were rare. Thermophiles, primarily bacteria, were present at low-to-moderate levels in homes, did not increase with watering of fan in homes, and rose only slightly with disturbance at greenhouse sites. Cladosporium and Penicillium dominated Andersen collections. Watering and fan increased levels of these taxa as well as rotorod recoveries of Alternaria. Epicoccum, and Pithomyces slightly in homes and markedly at greenhouse sites. We conclude that modest numbers of undisturbed house plants contribute minimally to aeroallergen prevalence in homes. However, especially under greenhouse conditions, plantings can harbor abundant fungus growth that may become airborne, especially when agitated directly.

Exclusion of particulate allergens by window air conditioners

Effects of window air-conditioner operation on intramural particle levels were assessed in the bedrooms of 20 homes and in 10 outpatient clinic examining rooms during late summer periods. At each site, pollen and spore collections in the mechanically cooled room and a normally ventilated counterpart were compared using volumetric impactors. Substantially lower particle recoveries (median = 16/m3) were found in air-conditioned rooms than in those with open windows alone (median = 253 particles/m3). Furthermore, substantial exclusion of small (e.g., Ganoderma spores) as well as large (ragweed pollens) aerosol components were found by window units. Control studies within normally ventilated rooms and outside their open windows showed a marked but variable inward flux of particles. Window units appear to substantially reduce indoor allergan levels by maintaining the isolation of enclosed spaces from particle-bearing outdoor air.

Characterization of Metalworking Fluid Exposure Indices for a Study of Acute Respiratory Effects

Although metalworking fluids have been widely used throughout industry for decades, occupational exposures to metalworking fluid aerosols and their constituents have not been well characterized. This article describes an exposure assessment for a study of metalworking fluid aerosols and acute respiratory effects. This exposure assessment was unique in its inclusion of multiple exposure measures relevant to a complex environment, and extensive personal sampling for bacteria and endotoxin. The specific objectives were to: (1) obtain indices of personal exposure to metalworking fluid aerosols in an automotive transmission plant, either directly (by sampling) or indirectly (by estimation), and (2) identify and adjust for sources of error in exposure/dose measures, where possible. No prior studies have characterized personal exposures to metalworking fluid aerosols so extensively. Exposure data were obtained during a pilot phase and three principal rounds of data collection over a 15-month period in conjunction with spirometric testing. Subjects worked in one of two machining departments, Case and Valve Body, or in a comparison department, Final Assembly. The primary exposure measures for this study were thoracic fraction particulate, thoracic fraction bacteria (viable plus non-viable), and total endotoxin. Mean personal air concentrations of thoracic particulate across all study rounds were 0.13 mg/m3 in Final Assembly, 0.32 mg/m3 in Valve Body, and 0.56 mg/m3 in Case. Average personal exposures to thoracic fraction bacteria were 0.38 bacteria/cc in Final Assembly, 0.87 bacteria/cc in Valve Body, and 2.66 bacteria/cc in Case. Average personal endotoxin measurements, collected in Round 3 of the study, were 16.4 endotoxin units (EU)/m3 in Assembly, 34.7 EU/m3 in Valve Body, and 234 EU/m3 in Case. Sump fluid contained on the order of 10(8) bacteria/ml, and 10(4)-10(5) EU/ml. Air concentrations of thoracic particulate, thoracic bacteria, and total endotoxin were highly correlated in metalworking operations. Thus, reducing airborne particulate levels should also reduce ambient bacteria and endotoxin, which are suspect agents of respiratory impairment. The elevated endotoxin levels in Final Assembly were unexpected, and suggest an independent source of endotoxin contamination in this department.

Performance of adhesives for rotating-arm impactors

Particle collections by paired rotoslide surfaces coated differentially with either of two silicone greases, white petrolatum or Lubriseal, were compared in two series of studies. Three samplers were employed, and adhesives were assigned randomly to the six available positions. Recovery differences were small but occasionally significant, with counts generally highest for silicone grease and lower with Lubriseal. During natural and simulated rainfall relative performances were similar, although differences were accentuated.

Basidiospore Structure and Development in the Genus Russula

Basidiospore development and spore-wall structure are presented for several species of Russula studied with the light and transmission-electron microscopes. Spore development is asynchronous until spores are 2 /m long, then synchronous. Ornamentation gradually appears, warts increasing in number with spore length and gradually becoming amyloid. The initially three-layered spore wall becomes six-layered at maturity. The ornamentation appears to be discontinuous and embedded in another wall layer. The amyloid material may be at the interface between the ornamentation layer and its matrix layer.

Crop Plants as a Source of Fungus Spores of Medical Importance

Fungi are primarily either decay organisms obtaining their food saprophytically or plant pathogens. Many have developed enzyme systems (for example cellulases, ligninases, and pectinases) that facilitate the decomposition of virtually any nonliving plant material, if appropriate water and temperature conditions are provided. Fungi, in fact, are responsible for most aerobic decay of such materials (Kendrick, 1985).

Quality control of multisource aeroallergen data

Abstract Pollen and spore prevalence data from 14 air sampling stations were retrospectively analyzed for accuracy of taxa identification and counting. Pollen identification was excellent and levels calculated by our laboratory closely matched those reported by most stations. Neither identifications nor counts were routinely reliable for fungus spores. While Alternaria was usually counted correctly, Cladosporium was frequently undercounted, and ascospores and basidiospores, which often constituted more than half the total spore load, were either not counted or severely undercounted. Errors resulted from undercounting, poor recognition, and reporting (including naming) errors. Multisite aerobiological studies that include documentation of fungus spore levels must include pretraining for each technician, and carefully documented standardization of counting and reporting procedures.