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PubMedDate not supplied

Effects in the rat of inhaling PVC dust at the nuisance dust level (10 mg/m3).

Rats inhaled a paste polymer polyvinyl chloride dust at an aerosol concentration of 10 mg/m3 for 6 hr/day, 5 days/wk for a 15-wk period. A small number of randomly scattered lung lesions were detected at 15 wk; these lesions were also present 15 wk after exposure to polyvinyl chloride had ceased. Few if any biochemical changes were detected at the alveolar surface in lung tissues or other organs of polyvinyl chloride-exposed rats. It is therefore concluded that at "nuisance" dust level this form of polyvinyl chloride polymer exhibits a weak biological reactivity.

Aerosols↗
PubMed1990

The use of dust-collecting cassettes in dust samplers.

This short paper highlights a possible source of error in the use of personal samplers for airborne dust due to deposition of particles on the internal surfaces between the sampling orifice and the filters. Dust collecting cassettes, incorporating sampling orifice and filters, are proposed as a means of eliminating such errors. The benefits and drawbacks of using cassettes are discussed and experiments carried out to investigate their magnitude.

Dust↗
PubMed2004

Dust measurements in the coma of comet 81P/Wild 2 by the Dust Flux Monitor Instrument.

We present measurements of the dust particle flux and mass distribution from the Stardust Dust Flux Monitor Instrument (DFMI) throughout the flyby of comet 81P/Wild 2. In the particle mass regime from 10(-14) to 10(-7) kilograms, the spacecraft encountered regions of intense swarms of particles, together with bursts of activity corresponding to clouds of particles only a few hundred meters across. This fine-scale structure can be explained by particle fragmentation. We estimate that 2800 +/- 500 particles of diameter 15 micrometers or larger impacted the aerogel collectors, the largest being approximately 6 x 10(-7) kilograms, which dominates the total collected mass.

Cosmic Dust↗
PubMed2001

Variations in exposure to inhalable wood dust in the Danish furniture industry. Within- and between-worker and factory components estimated from passive dust sampling.

Variability of exposure to wood dust at large factories in the Danish furniture industry was studied. Three repeated exposure measurements of 292 workers at 38 factories were included in the study. The measurements were carried out by use of personal passive dust monitors. The components of variance were estimated by means of a random effects ANOVA model. The ratio of within- to between-worker variance was 1.07. Based on this result, and three repeated exposure measurements, the observed relation between health outcome and exposure will be attenuated to 74% of the true value. Grouping by factory showed very poor exposure contrast, as the contrast in exposure level among factories was as low as 0.15.

Air Pollutants, Occupational↗
PubMed1998

[Effect of impactor sampling on the ratio of respirable dust concentration to total dust concentration].

The aim of this study was to verify the change of the ratio of Respirable Dust Concentration (RDC) to Total Dust Concentration (TDC) taken by two-stage impactor sampling. The results showed that there was a correlation between the ratio of RDC/TDC and TDC (correlation coefficient was 0.8576, 0.8689, 0.8736 and 0.9674, respectively) under the condition of identical sampling volume, and the ratio increases along with the elevated TDC.

Air Pollutants, Occupational↗
PubMed1976

Treatment of allergy to house dust with pyridine-extracted alum-precipitated extracts of the house dust mite.

Two preliminary trials in which patients with respiratory allergy to the house dust mite were treated with pyridine-extracted alum-precipitated extracts of house dust mites are described. In the first, using an extract of D. farinae, twenty-two of twenty-eight asthmatic patients improved. In the second, using an extract of D. pteronyssinus, fifteen of eighteen asthmatic patients improved.

Alum Compounds↗
PubMed1977

[Immunologic investigations of house-dust and house-dust mites. I. Schultz-Dale test (author's transl)].

With Dermatophagoides pteronyssinus and house-dust sensitized guinea-pigs showed cross-reactions between house-dust, D. pteronyssinus and D. farinae in the Schultz-Dale test. Euroglyphus maynei gave positive reactions only in animals sensitized with D. pteronyssinus. The stored food mites Tyrophagus putrescentiae, Chortoglyphus arcuatus and Glycyphagus destructor and the rearing medium (horse dander/yeast) did not cause any cross-reactions in any test group.

Allergens↗
PubMed1986

[House dust mites in bed dust and on the body].

In the urine of a ten-year-old girl mites of the species Tarsonemus minusculus (Can et Fanz.) and Cheyletus eruditus (Schr.) were found. A following examination of the bed dust from the bed of the child produced yet two further species of house dust mites Dermatophagoides pteronyssinus (Trouess) and Tyrophagus putrescentiae (Schr.). The demonstration of Tarsonemus minusculus in this area is new, just as the hitherto unknown male of this species.

Animals↗
PubMed1985

Immunomodulatory effects of mineral dust. I. Effects of intraperitoneal dust inoculation on splenic lymphocyte function and humoral immune responses in vivo.

Syngeneic PVG rats and C57BL6 mice were inoculated with liquid suspensions of UICC chrysotile A asbestos, DQ12 quartz or the inert particulate TiO2. Rats received 10 mg and mice received 2.5 mg dust intraperitoneally on day 0. Injection of the pathogenic dusts asbestos and quartz was associated with a significant reduction in mitogenic response to PHA and Con A detected in splenocytes removed from animals 14 days after inoculation. Injection of TiO2 had no significant effect on splenocyte mitogenesis. Pretreatment of C57BL6 mice with asbestos intraperitoneally also impaired subsequent production of antibody to the protein antigen KLH. These data show that intraperitoneal injection of chrysotile A asbestos and DQ12 quartz had a marked effect on generalized T lymphocyte function. An additional immunomodulatory effect of asbestos injection was shown in C57BL6 mice where in vivo humoral immune responses were suppressed.

Animals↗
PubMed1986

Cross-reactivity between the house dust mite Dermatophagoides pteronyssinus and the mange mites Psoroptes cuniculi and P. ovis. I. Demonstration of antibodies to the house dust mite allergen Dpt 12 in sera from P. cuniculi-infested rabbits.

The cross-reactivity of the mange mites Psoroptes cuniculi (PC) and Psoroptes ovis (PO) antigens with the house dust mite Dermatophagoides pteronyssinus (DP) antigens has been studied. Cross-reactivity between mange mite and house dust mite antigens was demonstrated by both ELISA and immunoelectrophoresis by use of a sheep anti-DP antiserum. Both PC and PO were demonstrated to contain eight cross-reacting antigens. Sera from rabbits infested with PC were demonstrated to produce antibodies to the homologous immunogen, to PO antigens, and to DP antigens. Of the seven sera from infested rabbits tested, four were demonstrated to produce a strong antibody response to a major DP antigen Dpt 12, and two were demonstrated to produce a weak response that was judged empirically by double-diffusion analysis. Two sera were judged to react with the DP lipoprotein, Dpt 4. Sera from control rabbits did not demonstrate reactivity with any extract tested. Despite the detection of anti-Dpt 12 antibodies, however, an antigen corresponding to Dpt 12 was not detected in either PC or PO extracts. The findings that mange mite-infested rabbits produce antibodies that recognize DP antigens probably explain previous observations in which it was demonstrated that commercially obtained rabbit anti-immunoglobulin antisera contain anti-DP antibodies, a finding that suggests caution in the use of such reagents in studies designed to measure antibody responses to DP allergens.

Animals↗
PubMed1986

Inhalation of china stone and china clay dusts: relationship between the mineralogy of dust retained in the lungs and pathological changes.

A combined clinical, radiological, pathological, and mineralogical study was undertaken on 62 cases referred to the Medical Research Council Pneumoconiosis Unit by the Cardiff Pneumoconiosis Panel as Cornish china clay workers. Considerable pathological lesions were found in the lungs, both nodular and interstitial fibroses being present. Some men had worked with china stone but others had worked entirely with china clay. Nodular fibrosis appeared to be related to a high quartz content of the dust recovered from the lung, whereas among those with a high content of kaolinite dust in the lungs interstitial fibrosis was observed.

Adult↗
PubMed1990

[A comparative evaluation of the effect of the dust factor on the respiratory organs of workers in contact with drug and plant dusts].

A comparative analysis of the data on the influence of complex medicinal and vegetable dusts (jute, flax, kenaf) on the respiratory organs, revealed the clinical signs of the byssinosis symptom-group in 49 cases (7.34%) of 667 technological textile workers investigated, and 10 cases (5.8%) of 171 tablet shop workers at a pharmaceutical plant. Byssinosis and its syndrome developed among the workers engaged in "dust shops" after 13 +/- 2.5 years of work. Similarity of the clinical symptoms was also proved by bronchospasm pharmacological diagnostic test (to a greater degree than in the sample group).

Absenteeism↗
PubMed2005

Direct activation of gelatinase B (MMP-9) by hay dust suspension and different components of organic dust.

Matrix metalloproteinases (MMPs) are involved in tissue destruction in allergic airway diseases. We studied the ability of various allergenic substances to directly activate recombinant 92kDa proMMP-9. The substances included hay dust suspension (HDS) and its components (supernatant, particulate matter and wash fluid of particulate matter), storage mite extract and two Aspergillus fumigatus extracts. The allergen suspensions were incubated in vitro with proMMP-9. After incubation the conversion of proMMP-9 to 10kDa lower active forms were studied using gelatin zymography and Western immunoblot quantified by computerized densitometry. All studied allergens except HDS significantly and efficiently activated proMMP-9 as compared to a negative control. At the concentrations employed, the most potent activators were A. fumigatus extracts and mite suspension. The greater potency of mite and fungi as proMMP-9 activators suggests that these allergens may be more damaging to airways even at low concentrations.

Acaridae↗
PubMed2000

Long-term effects of specific immunotherapy, administered during childhood, in asthmatic patients allergic to either house-dust mite or to both house-dust mite and grass pollen.

In a retrospective study, asthmatic patients allergic to either house-dust mite (HDM) (Dermatophagoides pteronyssinus) (n = 34) or to both HDM and grass pollen (GP) (n = 14), and who were treated with specific immunotherapy (SIT) during childhood (mean duration of SIT: 61 +/- 9.70 months), were re-evaluated in early adulthood after mean cessation of SIT for 9.3 +/- 2.76 years. The results were compared to those of a control group of asthmatic patients (n = 42) with comparable asthma features, who were treated with appropriate antiasthmatic drugs during childhood, but who never received SIT. Re-evaluation was carried out with a standardized questionnaire, skin prick tests (SPT), and lung-function assessments. At the time of re-evaluation, the mean age in the SIT-treated group was 23.1 +/- 3.50 years; in the control group, it was 22.7 +/- 3.40 years. At re-evaluation, the risk of frequent asthmatic symptoms was three times higher in the control group than in the SIT-treated group (prevalence ratio: 3.43; P = 0.0006). The frequent use of antiasthmatic medication was also more pronounced in the control group, although the difference was not statistically significant (P=0.38). Lung-function parameters and results of SPT with HDM were comparable in both groups. It is concluded that SIT has long-term effects on asthmatic symptoms in young adults.

Adult↗
PubMed1999

Effects of house dust mite avoidance measures on Der p 1 concentrations and clinical condition of mild adult house dust mite-allergic asthmatic patients, using no inhaled steroids.

BACKGROUND: Exposure to house dust mite (HDM) allergens often results in worsening of asthma. Therefore, avoidance of exposure to HDM allergens is often proposed. Unfortunately, the most effective and feasible avoidance strategy is still not completely assessed. Consequently, we investigated the effects of a combined HDM avoidance strategy on HDM allergen concentrations and clinical condition of allergic, mild asthmatic, patients using no inhaled steroids. METHODS: Asthmatic patients, allergic to HDM, using no inhaled corticosteroids, were randomly allocated to an active (n = 76) or a placebo allergen-avoidance group (n = 81). Avoidance measures consisted of applying Acarosan(R) (placebo: water) to the living room and bedroom floors, and the use of HDM-impermeable covers for mattresses and bedding (placebo: cotton covers for mattresses only). Effects on allergen concentrations (Der p 1), FEV1, bronchial hyperresponsiveness, peak flow parameters and asthma symptom scores were studied during 20 weeks and controlled for the allergic status of the patients. RESULTS: The active covers reduced Der p 1 concentrations to 9.4% (P = 0.0001), and were always significant lower than in the placebo group (P = 0.0002). Acarosan(R) resulted in slight but significant decreases (twofold, P = 0.0001), both on living room and bedroom floors, but concentrations were never significantly lower than the placebo group. Although the combined avoidance strategy resulted in a considerable reduction in allergen load in the active group, no differences were seen between the two groups in any of the clinical parameters during the follow-up period in this group of allergic asthmatics, using no inhaled corticosteroids. Corrections for the allergic status did not alter these results. CONCLUSIONS: The combined avoidance strategy was effective in reducing HDM allergen concentration. This was especially achieved by the allergen-impermeable covers, while the effects of Acarosan(R) were only marginal. However, this allergen reduction was not reflected in a convincing improvement in clinical condition in this group of mild allergic asthmatics, using no inhaled steroids. Perhaps, a longer follow-up period would have resulted in more pronounced effects.

Administration, Inhalation↗
PubMed1983

Effectiveness of animal rotation in achieving uniform dust exposures and lung dust deposition in horizontal flow chambers.

An important source of variability of experimental results in inhalation toxicology originates from the nonuniformity of chamber concentrations. Two horizontal flow inhalation chambers were used in evaluating the effect of cage rotation within each chamber on the amount of alpha-quartz deposited in the lungs of male Fischer 344 rats. The alpha-quartz lung burden was determined by quantitative X-ray diffraction. A carefully designed animal rotation schedule significantly reduced the variability in the amount of alpha-quartz deposited in the animals, thereby minimizing effects of chamber nonuniformity due either to design or dust generator characteristics.

Aerosols↗