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At least 19 recordsLinked to original sources

[The importance of house dust mites and stored food mites as house dust allergens in the rural population].

House dust samples from rural districts contain more mite species (in particular stored food mites) than samples from urban areas, and the total number of mites is also approximately three times greater. 77 patients from rural districts, 48 of whom allergic to their own house dust, and 29 controls, were tested with mite extracts from Dermatophagoides pteronyssimus, D. farinae, Chortoglyphus arcuatus, Acarus siro, Glycyphagus destructor and Tyrophagus putrescentiae, and a house dust extract. Out of 32 patients who showed positive scratch tests to one or more mite extracts, 29 (90,6 percent) reacted positively to D. pteronyssimus, 25 (78.1 percent) to D. farinae and from 7 to 12 (20-40 percent) to the stored food mites. Out of the 48 patients allergic to their own house dust, 27 (56.2 percent showed positive reactions to D. pteronyssinus, 24 (50.0 percent) to the house dust extract and 21 (43.7 percent) to D. farinae. Only 5 (17.2 percent) out of the 29 controls reacted positively to one or more of the solutions tested. The stored food mites showed 2.5 to 4.5 times more positive reactions in the rural patients compared with the results obtained in urban patients. The importance of these mites in the sensitization of patients from rural districts is discussed.

Adolescent

IgE antibody response to mite antigens in mite infested mice.

Mice infested at birth with the mouse mite Myocoptes musculinus developed positive skin tests to mite antigens at the age of 5 weeks. Serum IgE antibodies directed against mite antigens were first detected at 6 weeks of age and high levels of IgE were present as long as 1 year later. Similar kinetics of IgE formation were observed in mice infected as adults. Mast cell degranulation by mite extract was demonstrated in connective tissue obtained from the skin of mite infested mice.

Aging

[The biology of the house dust mite Dermatophagoides pteronyssinus (Trouessart, 1897) (acarina:astigmata). I. Colonization of mites on new matresses].

The prevalence of the house-dust mite Dermatophagoides pteronyssinus in four different kinds of test mattresses was investigated. In a first series of experiments the mites showed no preference to any of the mattresses - irrespective of the stuffing material - when the surface was smooth and unstitched. In a second series of experiments two buttons each were sewed on on both sides of the mattresses. Subsequently the mites showed a distinct preference to the depressed area around the buttons. These findings were confirmed in used mattresses provided by patients. The importance of these "nishes" in relation to mite allergies is discussed.

Bedding and Linens

House dust mites in Switzerland. III. Allergenic properties of the mites.

The allergenic properties of the nine mite species prevalent in the house dust of northwestern Switzerland (Basel and surroundings) were studies. For the preparation of mite extracts, the average weight of each species was first determined and then the number per culture glass counted. Thus the extracts were prepared according to the weight of the mites. They were tested on 115 patients with ashma and/or rhinitis. Tests with patients own house dust and with a human dander/yeast mixture, which served as culture medium for the mites, were carried out simultaneously. Test results were either positive or negative for all substances in 93 patients (80 per cent). Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei caused the most frequent and most severe reactions. The species Glycyphagus destructor, G. privatus, Chortoglyphus arcuatus, Gohieria fusca, Tyrophagus putrescentiae and Acarus siro seem to play a less important role, if any, in house dust allergies.

Adolescent

Anti-mite measurements in mite-sensitive adult asthma. A controlled trial.

A cross-over controlled trial has been conducted among 32 adult patients with mite-sensitive asthma. The bedclothes and pillows of each subject were laundered and vacuum-cleaned and a plastic cover applied to the mattress for six weeks in an attempt to reduce exposure to mites. No improvement in daily peak-flow reading or drug usage was found in comparison with a control period.

Adult

A trial of house dust mite extract in bronchial asthma. Mite Allergy Subcommittee of the Research Committee of the British Thoracic Association.

Patients with asthma considered to be due to house dust mite allergy were allocated at random to treatment with (a) increasing weekly injections of house dust mite extract for 18 weeks followed by monthly injections to complete 18 months of treatment; (b) similar injections for 18 weeks followed by placebo injections up to 18 months or (c) placebo injections for 18 months. Fifty-six patients completed at least six months of observation. In patients not on corticosteroids the treated group did a little better than the controls as judged by night asthma scores, discontinuation of bronchodilators and overall blind assessment of the records by a panel of independent physicians. No benefit was apparent by extending treatment from 18 weeks to 18 months. In contrast, patients on corticosteroids given placebo injections did a little better than the treated group. The extract used was stronger than the commercially available preparation and the injections had to be stopped in one-sixth of the patients because of side-effects. The improvement in patients not on corticosteroids in this trial was of doubtful clinical importance.

Adolescent

Effect of reagins and allergen extracts on radioallergosorbent assays for mite allergen.

The reproducibility of the radioallergosorbent (RAST) inhibition and direct binding assys with mite allergen were investigated in the presence of heterogeneous extracts and non-mite-sensitive atopic sera. Both contain components similar to potential contaminants which would occur in the assay of mite allergen and dust allergen and dust allergen extracts. The standardized inhibition and direct binding assays employed had a day to day (n = 4) coefficient of variation [(s.d. x 100)/mean] of 15% and 24% respectively. The inhibition assay for mite allergen was reproducible in the presence of protein concentrations of added plant, fungal, arthropod and animal extracts in excess of the protein concentrations that occur under the operational mite assay conditions. The mite inhibition assay was also reproducible in the presence of non-mite allergen extracts, with and without additional sera containing IgE specific for the non-mite allergens. The binding of a additional sera containing IgE specific for the non-mite allergens. The binding of a constant quantity of mite allergen to the activated solid phase in the direct binding assay was reproducible in the presence of added bovine serum albumin, and of a fungal or arthropod extract, representing the heterogeneous components of an allergen extract at the concentrations of total protein known to occur in the direct binding assay of mite extracts.

Allergens

IgE antibody response to mite antigen in the mouse. Suppression of an established IgE antibody response by chemically modified antigen.

The antibody response to mite antigen in several mouse strains was studied. BALB/c, CBA, C3H/He, and C57B1 strains showed good responses against mite antigen. The AKR strain, on the other hand, showed a relatively poor response. When BALB/c mice were immunized with DNP-mite conjugate in aluminum hydroxide gel (alum), anti-DNP IgE antibody and IgG1 antibody were induced. When these mice were boosted with mite antigen alone in alum, both anti-mite IgE antibody and IgG1 antibody were induced, although these antibodies were not observed after the first immunization. Both IgE antibody responses were high and persistent. Mite antigen was denatured by alkylation and reduction in the presence of 8 M urea. Native antigen remaining in the chemically denatured antigen was removed by an immunoadsorbent method. The modified mite antigen could stimulate the carrier-specific helper cells, at least when it was injected with alum. It was also found that repeated injections of the modified mite antigen resulted in the suppression of an established IgE antibody response against mite antigen. These findings suggest possible clinical application for hyposensitization therapy.

Animals

Mite allergen content in commercial extracts and in bed dust determined by radioallergosorbent tests.

Radioallergosorbent (RAST) direct binding and inhibition type assays were used to quantitate the mite (Dermatophagoides pteronyssinus) allergen content of four commercial mite extracts and a laboratory prepared extract from freeze-dried mites. The content of mite allergen in extracts prepared from twenty samples of dust vacuumed from bedding was measured by RAST inhibition assay. The four commercial mite extracts designated A, B, C and D, and the laboratory extract, designated L, contained 52, 265, 108, 1.5 and 581 arbitrary units of allergen/ml for the direct binding assay and 128, 111, 217, approximately 1 and 1083 arbitrary, but different, units of allergen/ml for the inhibition assay respectively. Qualitative differences between at least two extracts were suggested by the different slopes obtained when allergen binding of anti IgE was plotted against the volume of extract used in the direct binding assay. Differences in slope between the two extracts were also apparent when they were used in the inhibition assay. The quantities of mite allergen/gm of bed dust expressed in arbitrary units for the inhibition assay were 24 to 457 (mean 129) units. These quantities are similar to and sometimes greater than the quantity in 1 ml of mite extract and so confirm bed dust as a potent source of mite allergen. There was no significant correlation between the weight of dust, the numbers of dead and live mites and the allergen content of dust.

Allergens

The role and allergenic importance of storage mites in house dust and other environments.

Skin tests were performed on 210 patients with house dust allergy and bronchial asthma or perennial rhinitis using extracts of Dermatophagoides pteronyssinus and of four storage mites most commonly found in house dust in the United Kingdom--Acarus siro, Tyrophagus putrescentiae, Lepidoglyphus (formerly Glycyphagus) destructor and Glycyphagus domesticus. The results of the skin tests were related to certain occupations and living conditions of the patients which could have exposed them to storage mites and some patients were included because their environment seemed especially likely to expose them to these species in order to assess the importance of these conditions. D. pteronyssinus was the most potent of the mite allergens and provoked the largest number of positive tests but a proportion of the storage mite species gave skin reactions which were larger or as large as those of D. pteronyssinus. No significant statistical correlation was found between reactions to D. pteronyssinus and any storage mite but highly significant correlations were found between some storage species. The frequency and strength of reactions to these species were unexpectedly high in view of their irregular occurrence and relative scarcity in house dust. It is suggested that sensitisation to these species occurs through exposure either to localised sources of infestation overlook during the random collection of floor or bedding dust or to infested materials encountered at work or other activities or to infested food or bedding of certain domestic pets. It is concluded that allergy to storage mites is more important and widespread that hitherto realised and is a considerable occupational hazard in farming communities and to those in occupations handling infested materials. Storage mites may also be important allergens for those living in very damp houses where the growth of moulds may encourage the development of Glycyphagus domesticus or other mites.

Adolescent

Mites in house dust in the Stockholm area.

Today there is no doubt that mites (and especially species within the Pyroglyphidae family: Dermatophagoides pteronyssinus and Dermatophagoides farinae) are an important agent in dust allergies. The author reports on a study of the occurrence of mites in house dust in the environment of allergic persons in the Stockholm area. 201 private homes, 13 farmers' houses and two hospitals have been studied. In 12% of the homes several different types of mite were found in dust in relatively small numbers, while pyroglyphids occurred in only 1.5% of the dwellings. The frequency of mites in dust from farmers' homes was three times higher and that of pyroglyphids ten times higher than in other dwellings. Mites were most often found in floor dust and very infrequently in bed dust. All hospital beds were free from mites; in floor-dust samples from a hospital for long-term therapy several species of mite were found. The author draws the conclusion that the conditions of climate and humidity within the geographical area studied are adverse to the development of an allergologically significant mite population in indoor dust, but that small numbers may spread from potted plants, work premises and outdoor flora.

Allergens

Midface toddler excoriation syndrome (MiTES) can be caused by autosomal recessive biallelic mutations in a gene for congenital insensitivity to pain, PRDM12.

BACKGROUND: Midface toddler excoriation syndrome (MiTES) is a condition recently reported in three unrelated children. Habitual scratching from the first year of life inflicted deep, chronic, scarring wounds around the nose and eyes. One child had a mild neurological deficit but there was no other evidence of insensitivity to pain. Bilateral distribution and localization to the midface distinguish MiTES from other causes of self-inflicted skin damage such as trigeminal trophic syndrome. An earlier study of five siblings from a consanguineous Irish family, with lesions corresponding to MiTES plus other sensory deficits, showed homozygous mutations in a gene for hereditary sensory and autonomic neuropathy type VIII (HSAN8), PRDM12. OBJECTIVES: To study further cases of MiTES, including analysis of PRDM12. METHODS: We describe five further children, from four families, with facial lesions typical of MiTES, in whom mutation analysis of PRDM12 was carried out. RESULTS: Homozygous or compound heterozygous pathogenic expansions of the PRDM12 polyalanine tract were found in four of five affected individuals, in three families. CONCLUSIONS: Our finding of autosomal recessive mutations in PRDM12 in four of five patients with MiTES extends the phenotypic spectrum of PRDM12 mutations, which usually cause HSAN8, characterized by mutilating self-inflicted wounds of the extremities, lips and tongue. By contrast, MiTES shows severe midfacial lesions with little if any evidence of generalized pain insensitivity. The condition is probably genetically heterogeneous, and other congenital insensitivity to pain and HSAN genes such as SCN11A may be implicated. This new understanding of the nature of MiTES, which can masquerade as factitious disease, will facilitate appropriate management.

Alleles

The seasonal variation in a population of house dust mites in a North American city.

Mattress dust collected at monthly intervals for 2 1/2 yr was examined for mites. Both Dermatophagoides pteronyssinus and D. farinae were found. There was a significant association between the presence of live mites and the relative humidity (RH): Live mites were seen only when the RH had been greater than or equal to 50% for at least part of every day during the month of collection. There was a seasonal variation in that live mites were found only in the warmer months and not in the winter. However, the peak in the mite population was consistent neither for month nor for numbers: In 1977 a slight peak in mite numbers occurred in October, while in 1978 the peak was higher and occurred in July. Use of data from previously published studies to preduct mite levels may therefore be misleading.

Animals

The relationship of the house-dust mite to respiratory allergy.

1. The house-dust mite is a potent and important allergen. 2. 11.2% of patients with perennial respiratory allergy are allergic to the mite allergen and not to the various dust allergens. 3. 39.6% of the patients allergic to the allergens of house-dust are allergic to the allergen of the house-dust mites. 4. 23.7% of patients allergic to the allergens of house-dust are not allergic to the allergen of the house-dust mite. 5. 25.2% of patients with perennial respiratory allergy are not allergic to either the house-dust or mite allergens. 6. Endo, Center, or both dusts were negative in 222 cases, or 36.4%. 7.house-dust mites were negative in 297 cases, or 48.9%. 8. Positive intracutaneous skin tests with house-dust mite extract correlated with only 60.5% of the patients. Negative skin tests correlated with 67.3% of the patients.

Adrenocorticotropic Hormone

Elevated levels of IgE antibodies to ascaris and mite antigens in Papua New Guinea.

Levels of IgE as well as specific IgE antibodies to ascaris and mite have been studied in two groups in Papua New Guinea (PNG), patients with primary liver carcinoma (PLC) and normal blood donors, and in two groups in Japan, normal subjects and asthmatic patients. A radioallergosorbent test was used to measure IgE antibodies to ascaris and mite antigens. Much higher levels of IgE were found in the Papua New Guinean subjects than the normal Japanese subjects. Also levels of IgE antibodies to ascaris were much higher in Papua New Guineans than in the Japanese subjects. Though similar results were observed in IgE antibodies to mite, difference between normal Papua New Guineans and normal Japanese was small, whereas difference between the patients with PLC in PNG and the normal Japanese subjects was very large. Highest levels of IgE antibodies to mite were detected in Japanese with asthma. No correlations were observed among IgE levels, levels of IgE antibodies to ascaris and levels of IgE antibodies to mite. It is concluded that both ascaris and mite IgE antibodies contribute the very high levels of IgE seen in Papua New Guineans, but many other factors may be operative.

Antibodies