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Biomedical subjects

M C Swanson

Publications and source records attributed to M C Swanson.

At least 37 records · Page 2Linked to original sources
PubMed1993

Airborne dust and aeroallergen concentration in a horse stable under two different management systems.

Airborne dust concentration (ADC) was measured in 2 different horse management systems using an Andersen cascade impactor in the box-stall, and a personal Marple cascade impactor attached to the halter to measure ADC in the breathing zone. The levels of aeroallergens implicated in chronic obstructive pulmonary disease were measured by radioallergosorbent-inhibition immunoassay. A conventional management system (System C) utilising hay feed and straw bedding, and a recommended environment (System R) utilising wood shaving bedding and a complete pelleted diet were studied. In the stall, total and respirable ADC (geometric mean) were significantly higher in System C (2.55 mg/m3; 0.44 mg/m3, respectively) than in System R (0.70 mg/m3; 0.20 mg/m3, respectively). In System C, the total and respirable ADC in the breathing zone (17.51 mg/m3; 9.28 mg/m3) were much higher than in the stall, but values in both regions were similar in System R (0.52 mg/m3; 0.30 mg/m3). Major aeroallergens were significantly higher in System C than in System R: Micropolyspora faeni (1423 ng/m3 and 705 ng/m3), Aspergillus fumigatus (1823 ng/m3 and 748 ng/m3), and mite allergens (1420 ng/m3 and 761 ng/m3). Measurement of ADC with personal samplers indicates that the very high inhalation challenge in the breathing zone is not reflected in measurements of stall air quality. When compared with System C, System R produced only 3% of the respirable dust burden in the breathing zone and a decreased aeroallergen challenge.

Air Microbiology↗
PubMed1992

Immunochemical quantification and particle size distribution of airborne papain in a meat portioning facility.

The use of enzymes in industry continues to expand. With this increased use comes a concerted need to better understand potential respiratory health hazards to exposed workers and to quantify exposure levels that cause impaired health. To this end, projects were undertaken by the National Institute for Occupational Safety and Health (NIOSH) Health Hazard Evaluations Program and Cole Associates whereby this information was collected. Data concerning medical evaluation and aspects of industrial hygiene are the subjects of two separate reports from these respective groups. This method/results report includes a description of (1) a sensitive immunoradiometric assay for the quantification of airborne papain and its particle size distribution, (2) measurement of papain from both general area and personal breathing zone air samples obtained from a meat processing plant that used this immunochemical analysis, (3) a sampling strategy, and (4) an improved air sample processing technique. Airborne papain was measured at levels ranging from low nanogram to microgram per cubic meter concentrations. Approximately half of the papain activity was associated with particles having an aerodynamic diameter of less than 9.4 microns. These data point to a need for containment and controls in the manufacture and use of such compounds. This approach can be considered by the hygienist as an effective tool to be used in conjunction with epidemiologic studies to help set standards that are practical, safe, and maintained.

Air Pollutants, Occupational↗
PubMed1991

Source of the aeroallergen of soybean dust: a low molecular mass glycopeptide from the soybean tela.

Airborne soybean allergens in the dust generated during the unloading of soybeans in the harbor caused asthma epidemics in Barcelona, Spain. The major allergen causing the epidemics was a glycopeptide less than 14 kd molecular mass abundant in soybean dust. This allergen occurs in all parts of the soybean plant at all stages of growth, but the telae (hulls) and pods are by far the richest source. Small amounts of a similar cross-reacting allergen are found in some other grain dusts. The botanical function and significance of this soybean plant component is not known nor is the potential for airborne dispersion of this allergen at other grain-handling sites.

Air Pollution↗
PubMed1991

Prevalence of specific IgE to the storage mite, Aleuroglyphus ovatus.

Aleuroglyphus ovatus (Ao) is a storage mite that has a worldwide distribution and has been found in stored bran, wheat, chicken meal, and dried fish products. Ao was isolated from a chicken meal sample, cultured on whole wheat flour at 75% relative humidity, and 1 gm of pure Ao bodies were extracted, 1:20 wt/vol, in 0.2 mol/L of ammonium bicarbonate. Der p I, major allergen of Dermatophagoides, pteronyssinus (Dp), or Der f I major allergen to Dermatophagoides farinae (Df), was not detected in extracts of Ao. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed 25 bands (6 to 110 kd), and thin-layer isoelectric focusing revealed 19 bands (isoelectric point, 3.5 to 9.3). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblots with six different sera identified nine IgE binding bands (16 to 100 kd). Thin-layer isoelectric focusing immunoblots identified 16 IgE binding bands (isoelectric point, 4.5 to 9.3). An aliquot of the Ao extract was diluted in bicarbonate buffer (pH 9.2) and adsorbed to plastic microtiter plates. RAST to Ao and Dp were performed with sera of 163 atopic individuals (88 with allergic rhinitis and 75 with allergic asthma with or without allergic rhinitis). All individuals had appropriately positive skin tests that correlated with a history of exacerbation secondary to allergen exposure. RAST results to Dp and Ao were analyzed by regression analysis (r = 0.64; p = 0.0001). Fifty-five individuals were RAST positive to Dp alone, 32 to Ao and Dp, and three to Ao alone; 73 individuals were negative to Ao and Dp. RAST inhibition demonstrated moderate cross-reactivity between Ao and Dp.

Adolescent↗
PubMed1991

Caffeine, a naturally occurring acaricide.

Since caffeine is a plant alkaloid that has been described as a naturally occurring insecticide, its acaricidal effect on Dermatophagoides pteronyssinus (Dp) was investigated. Twelve cultures were established by adding 30 Dp to 200 mg of Tetramin fish food and brewer's yeast (8:2 ratio); six cultures were treated with 20 mg of finely ground caffeine. All 12 cultures were incubated at 75% relative humidity, 25 degrees C, and observed during 8 weeks. Live mites were then counted under a stereoscope, cultures were extracted, and supernatants were analyzed for Der p I and Der f I allergen content with a two-site monoclonal RIA. Live mite counts in untreated cultures varied from 146 to 274 (215 +/- 47.1), and in caffeine-treated cultures from 0 to 3 (1 +/- 1.2; p less than or equal to 0.0001). Der p I concentrations in untreated cultures varied from 588 to 9000 ng/gm (3138.3 +/- 2990.8 ng/gm), and in caffeine-treated cultures from 52 to 117 ng/gm (78 +/- 23.8 ng/gm; p less than or equal to 0.01). Der p I was not detected in the food media or caffeine; Der f I was not detected in any of the cultures. Results demonstrate that caffeine inhibits mite growth and allergen production.

Acari↗
PubMed1990

Variability of cat-allergen shedding.

To study the differences in total allergen shed, nine cats were placed individually in a lucite chamber with an air sampler attached for 1 hour. With a RAST-inhibition assay that used specific cat IgE antibodies from cat-sensitive subjects, we ranked the allergen production of each cat. From these nine cats, three high producers and one low producer were studied further. Each cat's allergens were collected for two to four separate 1-hour intervals on 6 different days. The high producers' samples remained high in allergen content, and the low producer's sample remained low. An additional eight cats were selected for similar longitudinal measurements, and allergens from each of these 12 cats were collected during four 1-hour intervals on 2 different days and assayed for total allergy units (AUs) by RAST inhibition and for the major cat allergen, Fel d I, by a two-site assay with a monoclonal antibody. Shedding, particularly by high producers, varied considerably from hour to hour. We found a hundredfold difference in AUs between the mean rate of shedding of the highest and lowest producers and a sixfold difference in Fel d I units. Variation in rate of shedding of Fel d I accounted for about half the variation of shedding of AUs. Allergen shedding varies not only between cats but also in the same cat during the course of a day and between days. Male cats shed more than female cats.

Air Pollutants↗
PubMed1990

Role of ventilation, air filtration, and allergen production rate in determining concentrations of rat allergens in the air of animal quarters.

Concentration of any substance in the air of a room is determined by the ratio between the rates of its production and removal. Thus, high concentrations can result from high production, low removal, or a combination of the two. Air filtration can supplement ventilation in removing allergens from the air. Control of aeroallergen exposure at any particular location would be more rational and effective if the contribution of production, ventilation, and filtration were known. Using immunochemical assays for rat urinary protein allergen, we measured the rate of production by individual rats and the concentration of allergens in the air of rat animal quarters where the ventilation rate was about 15 changes per hour. We introduced two different high-efficiency filtration systems that provided additional clean air changes up to a maximum of 127 changes per hour. Male rats shed about 20 ng/min of allergen. Because of this high rate of production, substantial reduction in rooms that housed large numbers of animals required the very high air-exchange rates that were achieved with laminar flow small animal isolator racks. Measured concentrations agreed well with concentrations calculated from a mass balance equation whose terms included numbers of animals in the room, production rate by individual animals, and rates of ventilation and filtration. We suggest that this principle of considering both production and removal rates applies not only to devising means of reducing levels of rat allergens in rat rooms, but generally to other indoor allergens as well.

Air Pollutants, Occupational↗
PubMed1989

Correlations between levels of mite and cat allergens in settled and airborne dust.

Thirty homes in Rochester, Minn., 20 of which housed cats, were studied to compare cat and mite allergen concentrations in airborne and settled dust. With Air Sentinels in the bedroom and living room for airborne collections, and a Sample Vac for collections from living room carpet and bedroom mattress, immunochemical quantifications of each were made with various radiometric assays with polyclonal and monoclonal antibodies. The most significant correlations were found between airborne mite in the bedroom and living room (p less than 0.001) and airborne mite in the bedroom and dust from the bedroom mattress (p less than 0.001). Most houses had specific epitopes of both Dermatophagoides pteronyssinus and D. farinae, but D. farinae was present in greater amounts. In seven houses we found greater than 10 micrograms of group I mite allergen per gram of settled dust, indicating that some houses in Minnesota have concentrations of mite allergens high enough to cause allergic disease, even in the winter. Clinical interpretation of these data on air levels is hampered by uncertainty as to whether symptoms are more closely related to average steady-state exposure, which we measured, or to brief heavy concentrations. Further epidemiologic studies are needed to define the concentration of mite and cat allergens in the air that are risk factors for allergic disease. The concentration of cat allergen correlated with mite allergen in the air, but not in settled dust, presumably reflecting the fact that both are influenced by ventilation rate.

Air↗
PubMed1989

Aeroallergens in dairy barns near Cooperstown, New York and Rochester, Minnesota.

We sampled atmospheric barn air using a volumetric air sampler in ten barns near Cooperstown, NY and six barns near Rochester, MN, and, with radioimmunoassays, measured allergens of Aspergillus fumigatus, Thermoactinomyces vulgaris, Micropolyspori faeni, short ragweed, rye grass group I pollen, Alternaria (Alt-1), Dermatophagoides sp. Lepidoglyphus destructor, common insect allergen, mouse urine, rat urine, and cattle epithelium. The most abundant allergen present was A. fumigatus followed by L. destructor. This study provides initial data on barn aerobiology and demonstrates for the first time the abundance of L. destructor allergens in North American dairy barns. More comprehensive study of barns, poultry houses, confinement houses for swine, and other agricultural environments from various geographic locations is needed to define the allergen levels to which millions of farm workers are exposed each day. While most of the allergens were expected, the presence of airborne allergens reactive with antisera to Dermatophagoides suggests indirectly that substantial amounts of pyroglyphid mites are present in some barns.

Air↗
PubMed1988

Immunochemical quantitation, size distribution, and cross-reactivity of lepidoptera (moth) aeroallergens in southeastern Minnesota.

With an immunochemical method, we analyzed outdoor air samples during a 3-year period for concentrations of the predominant local species of moth, Pseudaletia unipuncta (Haworth). Airborne particulates were collected on fiberglass filter sheets with an Accu-Vol sampler located 1.5 m above ground on the southeastern Minnesota prairie. Filter eluates analyzed by RIA inhibition contained concentrations of moth protein peaking in June and August to September of each year, with levels comparable to reported immunochemically measured levels of pollen and mold allergens. These peaks also corresponded with total numbers of moths captured in light traps. Moth-allergen activity was distributed in particle sizes ranging from 0.8 to greater than 4.1 micron when sized samples were obtained by use of an Andersen cascade impaction head. By RIA inhibition, there was cross-reactivity between P. unipuncta and insects of different genera, families, and orders, but not with pollens or molds. Forty-five percent of 257 patients with immediate positive skin tests to common aeroallergens had positive skin tests to one or more commercially available whole body insect extracts. Of 120 patients with allergic rhinitis believed to be primarily caused by ragweed sensitivity, 5% also had elevated specific IgE to moths. We conclude that airborne concentrations of Lepidoptera can be measured immunochemically and that moths may be a seasonal allergen in the United States.

Air Pollution↗
PubMed1988

A study of the prevalence and clinical significance of venom-specific IgE.

The prevalence of unrecognized Hymenoptera-venom sensitization, assessed by venom skin tests (VSTs) in adults with no history of adverse reactions to sting, has been as high as 12% in previous epidemiologic studies. To assess further the clinical importance of positive VSTs in such individuals, we skin tested 33 subjects stung in the field during the preceding 12 months without reaction, and 33 persons who denied being stung in the preceding 3 years. Among the recently stung group, 12/33 had at least one positive VST (greater than or equal to 2+) at 1.0 microgram/ml, whereas 5/33 had positive VST at 0.1 microgram/ml. In contrast, only 2/33 nonstung subjects had positive VST at 1.0 microgram/ml, and none were positive at 0.1 microgram/ml. To estimate, prospectively, the sensitization rate after insect stings, we studied a third group of 11 nonsensitive patients with negative skin tests to Hymenoptera. After a deliberate in-hospital honeybee sting, only 1/11 developed a persistently positive honeybee VST. From among the three groups, we then performed nine sting challenges in eight patients with positive VSTs, and all stings were tolerated without significant reaction. We also measured IgE antibodies to Hymenoptera venoms in random blood bank donors. During April to May, 2/216 sera contained elevated venom-specific IgE antibodies, whereas 14/201 sera collected from October to November contained elevated venom-specific IgE antibodies. We conclude that a small but appreciable portion of the population has venom-specific IgE antibodies and that the prevalence is seasonably variable. Our data indicate that persons recently stung without significant reaction contribute to this group but that only a small portion of this group is at risk for a systemic reaction with a future sting.

Adolescent↗
PubMed1988

Identification of a German cockroach-specific allergen by human IgE and rabbit IgG.

To further study the immunology of insect hypersensitivity, we identified and partially characterized the principal allergens in whole body German cockroach (WBGCR) (Blattella germanica) and compared this extract to whole body antigens prepared from other insects. WBGCR extract was fractionated over a calibrated Sephadex G-200 column; peak allergenic activity was contained in fraction 3 (GCR3), containing components with apparent molecular weights ranging from 12,500 to 75,000 daltons. The antigenicity, allergenicity, and specificity of GCR3 components were tested by using rabbit antisera raised to GCR3 or true armyworm (Pseudaletia unipuncta). Radioimmunoassay, cross-inhibition and immunoblot studies revealed, particularly in the IgE system, that GCR3 contained an allergen with a pI of 6.7 and MW of 36,000 daltons that was unique to WBGCR extracts and not present in other insect species, including true armyworm, caddis fly, lakefly, yellow jacket, or honeybee. This GCR3 component may represent a specific marker for the diagnosis of cockroach hypersensitivity in an insect-sensitive population of individuals.

Allergens↗
PubMed1987

IgE and IgG antibodies to beta-propiolactone and human serum albumin associated with urticarial reactions to rabies vaccine.

We examined the antibody response to a rabies vaccine doubly inactivated with 0.025% beta-propiolactone and 0.1% tri(n)butyl phosphate and stabilized with 2.5% human serum albumin. Antibodies were measured by using the following four antigen preparations: complete doubly inactivated rabies vaccine, rabies vaccine inactivated only with tri(n)butyl phosphate, beta-propiolactone and human serum albumin, and human serum albumin alone. The fluid phase of the preparation of beta-propiolactone and human serum albumin completely inhibited IgE binding to solid-phase vaccine. Of 21 subjects with urticarial reactions to a booster, 19 had IgE to doubly inactivated vaccine and to beta-propiolactone and human serum albumin. None of 27 immunized subjects without urticaria had detectable IgE. In paired pre- and postimmunization sera, IgE appeared in six of seven of the subjects with urticaria and in one of seven nonreactors. These sera did not contain a significant level of IgE to singly inactivated vaccine or to human serum albumin alone.

Antibodies, Viral↗
PubMed1987

Antigens and allergic asthma.

There are few reliable epidemiologic data on the overall frequency and importance of allergy. We describe a practical method for quantifying the concentration of both amorphous and morphologically defined antigens in the air. A high volume air sampler is used to collect airborne particles and has a facility to separate samples into different particle sizes. Samples are tested for allergenic activity by radioallergosorbent test inhibition assay. Preliminary findings from studies of community wide, amorphous and common household allergens are reported.

Air↗
PubMed1986

Immunologic response to aerosols of affinity-purified antigen in hypersensitivity pneumonitis.

On epidemiologic grounds, respirable particles from chilled-water air-conditioning systems in textile production plants have been implicated as a cause of hypersensitivity pneumonitis. We have purified the antigen from scum growing in this chilled water by antibody-affinity chromatography by use of IgG isolated from a pool of serum obtained from three workers with disease. Two patients with the disease, three coworkers without the disease, and two unexposed control subjects inhaled a dose of the purified antigen approximately equivalent to that amount calculated to be inhaled during an 8-hour work shift. Both workers with disease experienced fever, malaise, cough, and dyspnea 6 to 8 hours after the aerosol challenge. In these two patients the exposure evoked a transient decrease in circulating lymphocytes, predominantly T cells. Before challenge the patients' peripheral blood mononuclear cells demonstrated a blastogenic response to the antigen. The responding cells had disappeared from the circulation 24 hours after the challenge. Seventy-two hours after the challenge, mononuclear cells that were producing large amounts of specific IgG antibody appeared in the circulation. We conclude that the same antigen(s) that react with IgG antibody produced an acute episode of the disease, that specific antigen-recognition cells disappear from the peripheral blood after exposure to the antigen (presumably because they are attracted to the lung), and that antibody-forming cells appear in the peripheral blood approximately 2 days after a challenge. These antigen-specific reactions of circulating mononuclear cells may be specific for the disease, but studies on a larger number of cases are needed to be certain.

Aerosols↗