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At least 883 records · Page 49Linked to original sources
PubMed1996

Species-specific measurement of the second group of Dermatophagoides mite allergens, Der p 2 and Der f 2, using a monoclonal antibody-based ELISA.

BACKGROUND: The group 2 Dermatophagoides mite allergens, Der p 2 and Der f 2, were known to be highly crossreactive, and previous assays to measure Der p 2 and Der f 2 were not species-specific. OBJECTIVE: The aim of this study was to develop a monoclonal antibody-based ELISA (MoAb-ELISA) to species-specifically measure Der p 2 and Der f 2. METHODS: The MoAb-ELISA for Der p 2 and Der f 2 was performed using species-specific MoAbs for Der p 2 and Der f 2 and a biotinylated second MoAb which recognized a common epitope on both Der p 2 and Der f 2. RESULTS: The assay was highly species-specific, reproducible and sensitive. Thirty-two house dust samples were assayed by the MoAb-ELISA for Der p 2 and Der f 2 and by a previously reported radioimmunoassay for Der 2 with rabbit anti-Der 2 antibodies. The summed values for Der p 2 and Der f 2 by the MoAb-ELISA demonstrated a good correlation with the Der 2 values using the radioimmunoassay (r = 0.978). Furthermore, the proportion of the Der p 2 level in the total Der 2 level (Der p 2 divided by Der p 2 plus Der f 2) correlated well with that of the D. pteronyssinus mite number to the total Dermatophagoides mite number identified by species (r = 0.970). CONCLUSION: The MoAb-ELISA for Der p 2 and Der f 2, as well as that of Der p 1 and Der f 1, will be useful for the standardization of mite extracts and for the assessments of mite allergen exposure.

Animals↗
PubMed1997

Identification of T-cell epitope sequences on an important mite antigen.

BACKGROUND: T-cell epitopes on Der 1 and Der 2 groups, the major mite allergens, have been intensively analysed, while those on the other important allergens remain to be elucidated. We have cloned four cDNAs coding for important mite allergens on the basis of frequency and capacity of IgE binding. Stimulatory action of glutathione S-transferase-fused Mag1 on lymphocytes from mite-allergic patients was relatively high among them. OBJECTIVE: To identify T-cell epitopes on Mag1, we studied the stimulating activity of truncated Mag1 proteins and synthetic peptides on proliferative response of lymphocytes from mite antigen-immunized mice and mite-sensitive patients. METHODS: Truncated Mag1 proteins were expressed as a fusion protein with beta-galactosidase in Escherichia coli pop2136 carrying a variety of deleted Mag1 inserts. Murine T-cell epitope regions were estimated by the truncated antigen-induced lymphocyte proliferation assay. Overlapping peptides covering the whole sequence of the presumed T-cell epitope regions were synthesized to identify the epitope core sequences using murine and human Mag1-specific T-cell lines. RESULTS: Amino acid range 56-70 on Mag1 molecule showed remarkable stimulatory action on murine T cells, while amino acid ranges 51-65 and 86-100 had potent stimulatory activity on human T cells. CONCLUSIONS: These results suggest that Mag1 is a valuable antigen suitable for studies on T-cell responses and T-cell epitopes in mice and humans.

Animals↗
PubMed1996

Mitochondrial COI sequences in mites: evidence for variations in base composition.

Studies of mitochondrial DNA sequences in a variety of animals have shown important differences between phyla, including differences in the genetic codes used, and varying constraints on base composition. In that respect, little is known of mites, an important and diversified group. We sequenced a portion (340 nt) of the cytochrome oxidase subunit I (COI) encoding gene in twenty species of phytophagous mites belonging to nine genera of the two families Tetranychidae and Tenuipalpidae. The mitochondrial genetic code used in mites appeared to be the same as in insects. As is generally also the case in insects, the mite sequences were very rich in A + T (75% on average), especially at the third codon position (94%). However, important variations of base composition were observed among mite species, one of them showing as little as 69% A + T. Variations of base composition occur mostly through synonymous transitions, and do not have detectable effects on polypeptide evolution in this group.

Animals↗
PubMed1995

Species identification of Cecidophyopsis mites (Acari: Eriophyidae) from different Ribes species and countries using molecular genetics.

Cecidophyopsis mites were studied by PCR amplification of parts of their ribosomal DNA, followed by restriction enzyme analysis. Mite specimens on Ribes nigrum (black currant) from six countries gave the same digestion pattern, which was distinct from the pattern for mites found on R. rubrum from Poland and Finland and for R. grossularia from the USA. This suggests that each Ribes species is host to a different mite species: C. ribis, C. selachodon and C. grossulariae, respectively. Two other mite samples from R. alpinum and R. aureum were identical but were distinct from each of the other species.

Animals↗
PubMed1977

Pyroglyphid mites, xerophilic fungi and allergenic activity in dust from hospital mattresses.

Dust from mattresses of different composition and age was analysed for mites, xerophilic fungi and allergenic activity. The mites of the genus Demodex were the most abundant (58.2 per cent). Also pyroglyphid mites occurred commonly (36.6 per cent). Pyroglyphid mites were present in small numbers (mean: 1 specimen/0.2 g of dust) in 12 out of the 17 older polyester-foam mattresses. The 11 cotton-horsechair mattresses and the newly used polyester-foam mattresses (three tested) were without them. The dust from the cotton-horsehair mattresses had a significantly higher allergenic activity than from those of polyester-foam. Xerophilic fungi were isolated in three out of 31 mattresses. The species isolated belonged to the genus Aspergillus and Eurotium. E. repens occurred most frequently. Disinfection of mattresses was suggested to have a negative influence on the occurrence of mites and fungi.

Allergens↗
PubMed1979

Dust mites. A 1-year study.

Mattress dust was collected by out-patients attending hospital for respiratory allergic problems. The dust mites were counted in "pool" samples of 100 mg. Each sample represented a single month's collection. The mites were classified according to family: Pyroglyphidae and Cheyletidae. Those not belonging to either of these two families were classified as "other mites". Temperature and humidity during the period of the study showed no correlations with the number of mites. There was a statistically significant correlation between the various mite groups.

Allergens↗
PubMed1979

Mite fauna and fungal flora in house dust from homes of asthmatic children.

Mite fauna and fungal flora in the house dust from homes of asthmatic children with positive and negative skin test to house dust allergen and non-asthmatic controls were examined. There was no conspicuous difference in mite species distribution among the three groups. Pyroglyphid mites dominate the mite fauna in house dust more than half of which being Dermatophagoides: D. pteronyssinus and D. farinae. There was no statistically significant difference in numbers between the two species and either species could dominate depending on the conditions of the individual houses. The average number of acarina in 0.5 g of fine dust did not differ statistically among the three groups; however, mite number per square meter floor differed between patients with positive skin test and negative skin test. The results suggest that house-cleaning might influence the possible sensitization of children. The genetic distribution of mould fungi in house dust was largely similar to that of airborne fungi. The average number of fungal colonies detected in 0.5 g of dust did not differ statistically among the three groups. Wallemia with its minute spores may cause sensitization but has so far been insufficiently investigated.

Allergens↗
PubMed1979

Inhibition experiments with solid phase mite or epithelia in house dust hypersensitivity.

The present study was undertaken to verify that mites are not the only allergens in house dust extracts and that other allergens such as cat epithelia can also be responsible for house dust hypersensitivities detected both by house dust skin tests and house dust RAST studies. In order to determine whether mite or epithelia fixed on a solid phase could remove not only the IgE antibodies reactive with the homologous allergens, but also the IgE antibodies reactive with house dust allergens, the authors have absorbed 10 sera of house dust allergic patients with solid phase mite or epithelia. The absorption procedure removed a large part of the IgE antibodies reactive with specific immunosorbent (Dermatophagoides pteronyssinus or cat epithelia) and in the same way the IgE antibodies reactive with house dust immunosorbent. The percentage of RAST inhibition varied from 65% to 92% for Dermatophagoides pteronyssinus and from 65% to 94% for house dust in patients allergic to house dust and mite; the percentage of RAST inhibition varied from 67% to 92% for cat epithelia and from 73% to 90% for house dust in patients allergic to house dust and cat epithelia. This is in accordance with the hypothesis that house dust is not an allergen per se, but rather a complex mosaic of several allergens including mite, animal epithelia, etc.

Absorption↗
PubMed1983

House-dust mites and absolute indoor humidity.

The concentration of house-dust mites (Dermatophagoides spp.) was investigated for four seasons in three locations in each of 50 Danish apartments. Simultaneously the absolute humidity was recorded and the previously known correlation between mite counts and indoor humidity was confirmed. It appeared, however, that apartments which had a low absolute indoor humidity in the winter period (due to low household load of water vapour) did not contain noticeable concentrations of house-dust mites in the summer and autumn despite the fact that the indoor absolute humidity in these apartments could be high enough to allow for a high peak-population of mites. Because of this it is suggested that in a temperate climate avoidance measures against house-dust mites should be supplemented at least by a drying out period in the winter, when this process is convenient to perform because of the low outdoor absolute humidity.

Animals↗
PubMed1988

Prevention of mite infestation of bedding by means of an impregnated sheet. A randomized controlled trial.

A randomized controlled trial was conducted to test the effect of a sheet impregnated with benzyl benzoate in preventing mite infestation of new bedding. Impregnated sheets were placed on the mattresses of 17 subjects, while 19 subjects received placebo sheets. Over the following 2 years infestation occurred more commonly, and tended to be heavier, in the beds with inactive sheets than in those with impregnated sheets; among the 27 beds with three items of new bedding sampled on four occasions, a mite count of five or more occurred significantly more often where the sheet was inactive than where it was active (11 of 13 and 5 of 14 respectively). The application of a sheet impregnated with benzyl benzoate appears to prevent mite infestation and may be useful for patients with mite allergy who obtain new bedding as part of a mite-avoidance regimen.

Asthma↗
PubMed1989

House dust mite, Dermatophagoides pteronyssinus, and its allergens: effects of washing.

The study was undertaken to evaluate the effect washing at various temperatures would have on the house dust mite, Dermatophagoides pteronyssinus, and its allergens. Young and old mite cultures underwent a simulated washing programme. To record the number of live mites prior to and after washing a new counting method was applied. The findings demonstrated that although washing reduced the number of live mites, a washing programme at minimum temperature 58 degrees C was required in order to achieve complete extermination of the house dust mites. A distinct protein loss was observed when washing at higher temperature, thus further reducing the total allergen pool without loss of allergen activity as determined by direct RAST.

Allergens↗
PubMed1992

Concentration of airborne mite allergens (Der I and Der II) during sleep.

Using a low-noise air sampler and a sensitive radioimmunoassay, we measured the concentration of mite allergens in the air during sleeping with Japanese bedquilts (futon). The airborne allergen levels of Der I (Der p I plus Der f I) and Der II during sleep were 223 and 87.1 pg/m3 of air, respectively. These levels were about 10-fold higher than those during usual domestic life in the living room of the same houses. When the bedquilts were changed to new ones free of mite allergens, the airborne allergen levels of Der I and Der II were decreased to 11.5 and 12.0 pg/m3, respectively. This indicated that the mite airborne allergens during sleep were generated from the used bedding, not from the floor. We believe that exposure to airborne mite allergens during sleep might be an important factor in the development of mite allergies.

Air Pollution, Indoor↗
PubMed1998

House dust mite exposure as a risk factor for asthma: benefits of avoidance.

There is a dose-response relation between the level of exposure to house dust mite allergen and the risk of acquiring sensitization to this allergen as well as the risk of developing asthma. This relation is apparent at levels of exposure below 10 microg/g. In communities where nearly all houses have house dust mite allergen levels above this threshold, all susceptible individuals will be affected, and the relation to house dust mite exposure will not be apparent. Although these observational data would suggest that reducing exposure to house dust mite allergen should lessen the risk of developing sensitization and asthma, definitive evidence from randomized controlled trials is not yet available. Of the many clinical trials of house dust mite avoidance as therapy for asthma, only a few have produced sustained, substantial reductions in allergen levels in the bed. These effective interventions all included allergen-impermeable encasement of mattresses along with other strategies. In most trials where allergens levels were successfully reduced, there were clinical benefits for patients with asthma.

Allergens↗
PubMed1998

Use of milbemycin oxime in the treatment of dogs with nasal mite (Pneumonyssoides caninum) infection.

Clinical diagnosis of canine nasal mite (Pneumonyssoides caninum) infection is difficult due to the mite's location in the caudal nasal cavity and frontal sinuses. The current study was performed to evaluate the efficacy of milbemycin oxime in treating dogs with nasal mite infection. A prospective open uncontrolled study included 20 dogs with case histories indicating possible nasal mite infection. Inclusion criteria consisted of either nasal mites being demonstrated (group 1, four dogs), or suspicious clinical signs with no other apparent causes, combined with eosinophilia (group 2, 16 dogs). Milbemycin oxime 1 mg/kg was given orally three times at 10-day intervals. In 17 (85 per cent) dogs, clinical signs resolved completely following milbemycin therapy; within 10 days of the first treatment in 13 cases (group 1, four dogs; group 2, nine dogs) and within 14 days in four cases. In the remaining three dogs clinical signs persisted but were diminished.

Animals↗
PubMed1979

Reduction of contact sensitivity reactions to oxazolone in mite-infested mice.

Oxazolone-sensitized mite-infested (SWR-M) and mite-free (SWR-J) mice were challenged with oxazolone on the skin of the neck and shoulder. The migration of radioactively labeled cells to the site of contact sensitivity reaction to oxazolone was significantly less in SWR-M than in SWR-J mice. Serum obtained from SWR-M mice suppressed the extravasation of cells into the skin site of SWR-J mice challenged with oxazolone. The decrease in cellular influx in SWR-M mice occurred in areas of mite infestation (skin of neck and shoulder) as well as in areas not infested with mites (the ears). SWR-M mice also gave evidence of enhanced vascular permeability. A possible role for histamine in the inhibition of contact sensitivity in mite-infested mice is discussed.

Animals↗
PubMed2005

Plant virus HC-Pro is a determinant of eriophyid mite transmission.

The eriophyid mite transmitted Wheat streak mosaic virus (WSMV; genus Tritimovirus, family Potyviridae) shares a common genome organization with aphid transmitted species of the genus Potyvirus. Although both tritimoviruses and potyviruses encode helper component-proteinase (HC-Pro) homologues (required for nonpersistent aphid transmission of potyviruses), sequence conservation is low (amino acid identity, approximately 16%), and a role for HC-Pro in semipersistent transmission of WSMV by the wheat curl mite (Aceria tosichella [Keifer]) has not been investigated. Wheat curl mite transmissibility was abolished by replacement of WSMV HC-Pro with homologues of an aphid transmitted potyvirus (Turnip mosaic virus), a rymovirus (Agropyron mosaic virus) vectored by a different eriophyid mite, or a closely related tritimovirus (Oat necrotic mottle virus; ONMV) with no known vector. In contrast, both WSMV-Sidney 81 and a chimeric WSMV genome bearing HC-Pro of a divergent strain (WSMV-El Batán 3; 86% amino acid sequence identity) were efficiently transmitted by A. tosichella. Replacing portions of WSMV-Sidney 81 HC-Pro with the corresponding regions from ONMV showed that determinants of wheat curl mite transmission map to the 5'-proximal half of HC-Pro. WSMV genomes bearing HC-Pro of heterologous species retained the ability to form virions, indicating that loss of vector transmissibility was not a result of failure to encapsidate. Although titer in systemically infected leaves was reduced for all chimeric genomes relative to WSMV-Sidney 81, titer was not correlated with loss of vector transmissibility. Collectively, these results demonstrate for the first time that HC-Pro is required for virus transmission by a vector other than aphids.

Animals↗
PubMed1978

House dust mite sensitivity in childhood asthma.

The clinical features of perennial asthmatic children with a skin or bronchial reaction to the house dust mite (Dermatophagoides pteronyssinus) were compared with those of asthmatic children without mite sensitivity. Mite sensitive asthma was characterised by an early age of onset of symptoms, these being predominantly nocturnal. A history of wheezing precipitated by dust exposure, during vacuuming, bedmaking, or dusting was present in 52% of cases. Asthmatic children with mite sensitivity were more likely to have been born at the time of the year when mite counts were highest. This was consistent with the idea that allergy may be associated with a period of susceptibility to sensitisation in early infancy.

Adolescent↗
PubMed1975

Study of dust mites in three Birmingham hospitals.

Samples of dust were collected from wards in a general hospital, a geriatric hospital, and a skin hospital. Mites were found on the floors of all three hospitals; Surprisingly, the skin hospital showed fewer mites than the general hospital. The differences were attributed to the variation in ward activity, the number of visitors on the wards, and the differing cleaning regimens. Plastic-covered mattresses were almost completely free from mites, but foci were found on soft furnishings and on the jackets and overcoats of hospital workers. The total numbers of mites were small compared to those found in house dust, and hospital mites probably do not consitute a serious problem for asthmatic patients.

Allergens↗