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Biomedical subjects

W R Solomon

Publications and source records attributed to W R Solomon.

At least 37 records · Page 2Linked to original sources
PubMed1980

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.

Air Conditioning↗
PubMed1980

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.

Adhesives↗
PubMed1980

Microbial prevalence in domestic humidifiers.

The prevalence of viable thermophilic bacteria and actinomycetes and mesophilic fungi was examined in 145 samples from 110 domestic humidifiers. A total of 72 and 43% of furnace and console humidifier samples, respectively, contained viable thermophilic bacteria, whereas 60 and 72% of these samples produced mesophilic fungal growth. Thermophilic actinomycetes were recovered from seven humidifier samples. Efforts to detect thermophilic actinomycete antigens in 15 humidifier fluid samples were not successful. Antifoulants added to humidifier fluid reservoirs had no apparent effect on microbial frequency. Airborne microbial recoveries did not reflect patterns of humidifier contamination with respect to either kinds or numbers of microorganisms in 20 homes in which volumetric air samples were obtained during humidifier operation.

Air Microbiology↗
PubMed1979

Aerometric study of viable fungus spores in an animal care facility.

Studies of airborn fungi were undertaken to evaluate exposure risks for laboratory animals and human handlers which might lead to allergic or invasive disease. Although sporadically high fungus levels were encountered, counts of viable fungus particles were in general low. Recoveries on malt extract agar significantly exceeded those on Sabouraud dextrose agar. The taxa most frequently and abundantly recovered were Penicillium species. Data analyses suggest that 'clean' bedding material may be the principal source of these spores, that cleaning temporarily increases spore levels, and that outdoor airborne fungi contributed little to the indoor air spora identified. Aspergillus fumigatus was infrequently encounted in our samples, and dermatophytes were not recovered.

Air Microbiology↗
PubMed1978

Fungi in libraries: an aerometric survey.

The possible role of fungi as allergic contaminants in book collections has been investigated in eleven University of Michigan Libraries. Air in the stacks of each of the eleven libraries was sampled on three occasions (2 or 4--10 minute samples on each occasion) with Andersen Volumetric viable particle samplers. Books were handled during sampling in half the samples each day. In addition on each sampling day a location in the same building away from book storage and an outdoor location were sampled. Library spore levels were generally low. Outdoor levels consistently exceeded indoor levels. Air conditioned (AC) libraries had lower spore levels and indoor/outdoor ratios than conventionally ventilated (CV) libraries. Handling books during sampling increased spore counts in all libraries, but strikingly in CV libraries. Fungus taxa recovered were similar to those encountered in domestic interiors and outside locations in our area. The overall low spore levels and lack of a distinctive library mycoflora suggest that other sources should be sought for library-based respiratory symptoms.

Air Microbiology↗
PubMed1978

Airborne Aspergillus fumigatus levels outside and within a large clinical center.

Most considerations of Aspergillus fumigatus prevalence have implied that patterns of occurrence observed within London hospitals are generally applicable. Since prevalence data are almost nonexistent elsewhere, this assumption remains untested. To provide a comparison relevant to North America, we have monitored thermotolerant fungi outside as well as at two sites within the University Hospital, Ann Arbor, Michigan, during one year. Collections were made with paired Andersen samplers and malt agar for 30- to 40-min periods in a hallway adjacent to 6W, a general medical ward (47 days), and 2W, a lower level service and supply area (40 days); in addition, 10-min outdoor samples (44 days) were taken on an unobstructed hospital rooftop (out). Recoveries were analyzed after 3 and 7 days of 37 degrees C aerobic incubation. Virtually complete suppression of Cladosporium form species at 37 degrees left a mycoflora with A. fumigatus, A. niger, Paecilomyces spp., Mucor spp., and yeast/bacteria predominating. Although the proportions of samples yielding A. fumigatus were 76% for 6W, 57% for 2W, and 56% (out), levels exceeded 40 isolates/m3 only twice and were over 10 isolates/m3 on only 10 of 131 total samples. For 6W, 2W and out, respectively, means were 4.78, 1.97, and 6.25 isolates/m3; medians were 1.20, 1.05 and 1.75/m3 without annual trends indoors and with only a limited outdoor summer increase. Our data fail entirely to show the fall-winter abundance observed in the London report and suggest substantially lower indoor exposure levels of A. fumigatus than those noted in London.

Air Microbiology↗
PubMed1977

Comparative recoveries of airborne fungus spores by viable and non-viable modes of volumetric collection.

The suitability of viable and non-viable volumetric collectors as prevalence indicators for potentially allergenic airborne fungi was studied during 124 paired exposures of the Burkard (Hirst) spore trap and a modified, wind-oriented Andersen sampler. Overall, viable recoveries of several Cladosporium form species varied directly with microscopic spore counts (p less than or equal to 0.0001). However, as spore levels rose, culture plate data progressively underestimated prevailing concentrations (recoveries falling below 5% at levels above 500 spores/M3). Viable collections yielded low estimates of prevalence (20-40%) even at modest Cladosporium levels (less than 100 spores/M3) and substantially understated the abundance and regularity in air of several additional taxa. Spores typical of Penicillium and Aspergillus form species were not sought in spore trap deposits. Careful examination of these failed to reveal typical arthrospores or Fusarium macrospores despite substantial recoveries of corresponding growth in culture. Correlations in the occurrence patterns of arthrospore-forming and non-sporulating colonies with those of Coprinus and 'other basidiospores' (excluding Ganoderma) were noted.

Air Microbiology↗
PubMed1977

Comparative merits of eight popular media in aerometric studies of fungi.

Although cultural surveys of airborne fungi are pursued widely, the comparative virtues of popular media have not been systematically tested. To facilitate an informed choice, eight different agar media were compared using paired single-plate exposures of identical, wind-oriented, Andersen samplers. Modified Mehrlich's (MM), Sabouraud's dextrose (SAB), malt extract (MALT), V8 juice (V8), and potato dextrose-rose bengal (PDAR) agar were compared initially; potato dextrose (PDA), MALT, rose bengal streptomycin (RBS), and casein hydrolysate (CH) agar were compared during a subsequent series, as were PDA and PDAR. Overall, SAB, MALT, V8, and PDA total recoveries were similar, while MM, CH, PDAR, and RBS were significantly low in paired comparisons with one or more media. MALT and SAB produced the highest frequencies of recovery of most colony types. Bacteria were infrequently recovered on any of the media. CH and MM excluded Epicoccum but are of potential use in surveys that focus sharply on high concentrations of Cladosporium. Rose bengal-containing media performed poorly in this study and must be approached with caution and under properly controlled conditions.

Agar↗
PubMed1977

Effect of histamine and methacholine on nasal airway resistance in atopic and nonatopic subjects. Comparison with bronchial challenge and skin test responses.

Serial nasal, intracutaneous, or bronchial challenges were carried out with solutions containing 2- or 3-fold increments in histamine (H) or methacholine (Meth) concentration until nasal airway resistance (NAR) increased by more than 100%, a large intracutaneous reaction was elicited, or FEV1 decreased by 20% or more. Thirty nonatopic and 48 asymptomatic atopic subjects were studied, the latter group divided into rhinitic patients with and without asthma. Several types of data analysis demonstrated there was no significant difference in the nasal or cutaneous effects of H or Meth between the atopic and nonatopic groups. Comparable results were obtained in a subgroup of 39 subjects (13 normal, 13 atopic, and 13 atopic with asthma) who underwent all six test sequences (i.e., nasal, cutaneous, and bronchial with both drugs). As expected, the asthmatics showed significantly increased bronchial reactivity to both agents. In comparison with Meth, H had a much greater effect on the nasal mucosa and skin than on the bronchi. It is concluded that, contrary to bronchial responses, but in accord with cutaneous reactivity, the nasal responses of nonatopic subjects, atopic persons with allergic rhinitis alone, and subjects with both allergic rhinitis and asthma show no intergroup differences on testing with H or Meth.

Airway Resistance↗
PubMed1976

An improved technique for nasal inhalation challenge tests.

An improved technique for nasal inhalation challenge tests is described. It includes an improved delivery system utilizing a Maxi-Myst air compressor delivering a flow of room air controlled by an in-line, electroncially timed solenoid which precisely controls the duration of compressor activity. A No. 251 DeVilbiss atomizer will deliver 0.1 + 0.01 gm/spray when the flow rate is 11.5 L/min, the duration of atomizer activity is approximately 0.1 sec, and the amount of liquid in the atomizer insert is kept between 0.75 and 2.0 ml. Nasal aerosol challenge of 0.1 ml of isotonic phosphate-buffered saline per nostril produced less variability in nasal airway resistance (NAR) response than 0.2 ml, and the smaller volume proved satisfactory for 6 consecutive saline challenges at 15-min intervals. A new face mask, which did not impinge on the bridge of the nose or paranasal structures, yielded lower baseline values of nasal airway resistance and much less variability in these measurements. Techniques employed in objectively quantitating nasal responses to various exogenous substances are briefly but critically reviewed.

Administration, Intranasal↗
PubMed1976

A volumetric study of winter fungus prevalence in the air of midwestern homes.

Volumetric recoveries of airborne, mesophilic microfungi were made during winter months at three specific points in 150 single-family dwellings in southeastern Michigan. Mean levels of total isolates/m3 comprised a range of from less than 10 to over 20,000, although concurrent outdoor levels never exceeded 230/m3. Form species of Penicillium, Aspergillus, Cladosporium, and Rhodotorula as well as non-pigmented yeasts were the types encountered most widely indoors. Certain homes showed high recoveries of other types, including Cephalosporium, Sporobolomyces, Verticillium, and Sporothrix form species. A positive association between indoor fungus prevalence and bedroom relative humidity was strongly suggested, and high levels were observed in well-humidified homes despite the presence of electrostatic air cleaners. The data indicate characteristic patterns of (winter) air spora in specific homes and suggest that humidifying devices may serve as dispersion sources in addition to their permissive role in facilitating fungus growth.

Animals↗
PubMed1976

Volumetric studies of aeroallergen prevalence. I. Pollens of weedy forbs at a midwestern station.

Volumetric levels of pollens derived from broad-leaved herbaceous plant species heve been determined at a midwestern urban site with suction and rotating arm samplers. The resulting data confirm an abundance of ragweed and nettle emanations but suggest that those of plantains, chenopods, and amaranths achieve modest levels, at best, despite their prominence in gravity slide recoveries. Regular seasonal occurrence periods for pollens, including those of entemophilous composites, the hophemp group, wilg grape, and the mustard and pea families, were evident in volumetric recoveries. In general, prevalence peaks of the most prominent pollen types correlated with intermediate, rather than extreme, values for air speed and relative humidity.

Circadian Rhythm↗
PubMed1976

An appraisal of Impregon as a deterrent of domestic fungus growth.

Impregon brand of tetrachlorsalicylanilide (TCSA) has been profferred widely as a household fungistatic agent, although its value remains unproved. To assess its effects, this agent was used as a laundry and paint additive and as a treatment for burlap rug backing; after recommended applications of Impregon, coded replicate materials were inoculated with mixed suspensions of fungus particles. No difference was evident in fungus growth points on fabric swatches washed in tap water with and without Impregon. However, growth on both of these was significantly greater than on samples laundered in tap water using only a commercial soap or liquid detergent. Fungus soiling of burlap was not clearly diminished by prescribed applications of Impregon solution 3 mo previously. Similarly, the addition of this agent to paint did not suppress fungus growth on Masonite plaques to which it had been applied. However, comparable levels of Impregon incorporated into agar media substantially inhibited spore germination. These findings suggest that the bioavailability of TCSA is insufficient to provide desired household antifungal effects when Impregon is used in accord with current recommendations.

Air Microbiology↗
PubMed1976

The effects of topical saline and isoproterenol on nasal airway resistance.

Following determination of baseline nasal airway resistance (NAR) in human subjects, phosphate-buffered saline (PBS) was aerosolized into each nostril and NAR measurements repeated 8 times in 15 minutes. The mean maximal NAR increase in 102 subjects was 22.5% (SD +/- 24.5%) with no significant difference between atopic and nonatopic persons. Hay fever patients did not show significantly increased responsiveness to PBS while symptomatic. During 242 repeat challenges with PBS in 67 asymptomatic subjects, NAR increased over 50% in 24 tests. Following a series of 6 PBS challenges at 15-minute intervals, 10 of 71 subjects had more than a 100% increase in NAR over initial baseline values. Administration of PBS on cotton pledgets, pipetting PBS into the nose, or even just inserting a nasal speculum produced greater increases in NAR than the usual aerosol method. Intranasal atropine effectively blocked PBS-induced increases in NAR, suggesting parasympathetic stimulation as a mechanism. Isoproterenol increased NAR over 100% in 27 of 53 subjects, with no significant difference among rhinitic, asthmatic, and nonatopic individuals. This effect was inhibited by propranolol. Isoproterenol administration to 12 ragweed-sensitive subjects 15 minutes prior to ragweed challenge produced a variable inhibition in NAR responses or no protection at all. Thus the direct effects of isoproterenol on the nasal vasculature tend to outweigh those expected from inhibition of mediator release under the conditions of this study.

Administration, Intranasal↗
PubMed1975

Assessing fungus prevalence in domestic interiors.

Single-plate, Andersen sampler collections of mesonphilic imperfect fungi were made at three points in and immediately outside a series of midwestern homes. During frost-free periods, emanations of dark-spored form genera predominated at both points with indoor levels averaging 25% of those in outside air. At these times, volumetric recoveries and those by 30-min exposure of open culture plates have correlated tenuously (r = 0.29) in bedroom air of 20 homes. During winter, form species of Penicillium, Aspergillus, Oospora, Sporothrix, yeasts, etc. predominated indoors, with levels exceeding 1,000 particles/M3 noted in over 18% of homes; outdoor concentrations never exceeded 230 particles/M3. Comparisons of volumetric and open-plate recoveries from 50 homes during winter have revealed an almost random relationship (r = 0.06). These findings reflect the case with which outdoor spore clouds may penetrate structures and obscure evidence of internal fungus cources. The data also imply that, because of size-related undersampling, open plates often seriously misrepresent prevalence levels and occasionally can exclude abundant types from recovery. The fungus flora of enclosed spaces merits further critical study by volumetric techniques of calculable efficiency in a setting that minimizes contamination from without.

Air Microbiology↗