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Background: Partial mattress encasing was found to be effective in reducing exposure to mite allergen in our previous investigation. We aimed to compare the short‐term efficacy of partial and complete mattress encasing and to study mite‐allergen levels within these mattresses. Methods: Thirty‐one mattresses with high mite‐allergen content were selected and were randomized into one of three study groups (10 for the control group [CG], 11 for the partial encasing group [PE], and 10 for the complete encasing group [CE]). A special mite‐impermeable membrane was used. In the PE group, mattresses were encased on tops and sides only, whereas complete mattress encasement was undertaken in the CE group. Regular bedsheets were applied to all groups. Dust samples were collected over bedsheets at baseline and at months 3 and 6, and over mattresses at baseline and at the end of the study. Group I mite allergens in these samples were measured and compared. Results: At baseline, mattress mite allergens were similar in all groups (P=0.84). Mite allergen at the surfaces of bedsheets (over membranes) from both encasing groups were significantly reduced as compared to the CG group (P=0.003). Such reduction was maintained throughout the 6‐month study. At the end of the study, mite antigens within mattresses in the CG and CE groups were increased as compared to baselines, whereas a decrease was observed in the PE group. Significant difference was observed only between the CG and PE groups (P=0.006). Conclusions: Mattress encasing with a special membrane in this study was highly efficacious in the reduction of mite allergen (>90%). However, with complete encasing, mite allergens within mattresses were increased at the end of the study. Complete mattress encasing in a tropical environment does not offer any advantage over partial encasing. [ABSTRACT FROM AUTHOR]

House dust mites have been shown to be the most important source of allergen in Thailand. The results of our initial mite survey were in conflict with previous data reported 20 years ago. To evaluate the current condition of mite fauna in Thailand, we conducted a larger scale survey of house dust mites in dusts from three different parts of the country. A total of 630 mattress dust samples was collected from various types of housings from central, northern and northeastern parts of Thailand. House dust mites were identified and enumerated by standard techniques and 388 dust samples were analysed further for group 1 antigen by a two-site monoclonal antibody enzyme-linked immunosorbent assay. House dust mites were identified in 555/630 (88.1%) of dust samples collected; 27.6% of these 555 samples contained over 100 mites per gram of fine dust. Dermatophagoides pteronyssinus was the most abundant species found with a mean count of 87.2 mites per gram of dust (range 1–1460). Group I antigen was detected in 380/388 (97.9%) samples analysed and 330 of which (868%) contained over 2 μg/gm of group I antigen. The highest density of mites was found in dusts from northern Thailand whereas dusts with highest amount of antigen were those collected from the northeastern part. Some degree of correlation between mite count and mite allergen was observed (r² = 0.133, P < 0.001). No significant difference in the mite count and mite allergen was found among various types of housings. House dust mites are the source of allergens ubiquitously found all over Thailand. Dust from several houses surveyed in this study had significantly high level of group I antigens. [ABSTRACT FROM AUTHOR]

Background Allergy to specific shrimp species has not been studied systematically by oral challenges. A comparison of allergy to different shrimp species, especially seawater or freshwater varieties treatment, would be useful in testing shrimp-allergic subjects. Objective The aim of the study was to identify cases of specific allergy to seawater shrimp, Penaeus monodon ( Pm), or freshwater shrimp, Macrobrachium rosenbergii ( Mr), among shrimp-allergic children. Comparisons of skin tests using commercial and crude shrimp extracts plus the prick-to-prick (PTP) method were investigated. Methods Sixty-eight children with a history of shrimp allergy and skin tests positive to shrimp were orally challenged to both shrimp species. Reactivity to skin prick tests using extracts of Pm ( PmSPT), Mr ( MrSPT), commercial shrimp (ComSPT), and PTP tests ( PmPTP, MrPTP) was compared. Results Food challenges identified specific allergy to Pm and Mr in 17.65% and 23.53% of the subjects, respectively. Positive and negative challenges to both shrimp species were found in 47.06% and 11.76% of the subjects, respectively. Correlations between the mean weal diameter (MWD) from ComSPT– PmSPT, ComSPT– PmPTP, ComSPT– MrPTP, PmSPT– PmPTP and MrSPT– MrPTP, but not ComSPT– MrSPT, were observed. The MWD from PmSPT and PmPTP were significantly larger in patients with positive than negative challenges to P. monodon ( P<0.05). There was a trend that MWD from MrSPT were larger in patients with positive than negative challenges to M. rosenbergii ( P=0.058). In the Pm allergy group, PmSPT with an MWD of 30 mm provided 80% predictive probability for positive challenges. PmPTP and ComSPT with an MWD of 22.5 and 20 mm provided 95% predictive probability, respectively. In the Mr allergy group, MrSPT with an MWD of 30 mm provided 95% predictive probability. Conclusion Specific allergy to Pm or Mr was confirmed by food challenges. SPT using crude extracts and the PTP test are useful tools for screening shrimp sensitization before a food challenge. The predictive probability of SPT is helpful where a food challenge is not feasible. [ABSTRACT FROM AUTHOR]

Background Polymorphic sequence substitutions in the major mite allergens can markedly affect immunoglobulin E binding and T cell responses, but there are few studies on environmental isolates from Dermatophagoides pteronyssinus and none for D. farinae. Objective To determine the sequence variation of the group 1 and 2 allergens from environmental D. pteronyssinus and D. farinae. Methods RNA from each species was isolated from homes in Bangkok and the sequence of Der p 1, Der p 2, Der f 1, and Der f 2 determined from cDNA produced by high fidelity polymerase chain reactions. Results The enlarged data set revealed preferred amino acid substitutions in residues 19, 81, and 215 of Der p 1 as well as sporadic changes. Der p 2 showed frequent variations with clusters of amino acid substitutions, but the canonical Der p 2.0101 was not found in any of 17 sequences. Der f 2 showed variants with clusters of substitutions similar to Der p 2 but in different amino acid positions and without any structural concordance. Der f 1 in contrast to the other allergens had few amino acid sequence substitutions. Conclusions The sequence information on variants provides data important for the optimal design of allergen formulations and useful for the genetic engineering and structure–function analyses of the major allergens. [ABSTRACT FROM AUTHOR]

Wheat can cause severe immunoglobulin E (IgE)-mediated systemic reactions including anaphylaxis but knowledge on relevant wheat allergens at the molecular level is scanty.Seven children (aged from 6 months to 13 years) experiencing from 2 to 10 anaphylactic reactions in a year after eating food-containing wheat were examined. Purifiedω-5 gliadin was used as an allergen in IgE enzyme-linked immunosorbent assay (ELISA) and in skin prick testing (SPT). Wheat CAP radioallergosorbent test (RAST) and SPT were also examined.All seven anaphylactic children, but none of 15 control subjects had IgE antibodies toω-5 gliadin in ELISA. Five of the six tested anaphylactic children showed positive SPT toω-5 and crude gliadin, and all seven had positive wheat CAP RAST and SPT. One child was challenged with wheat, which caused anaphylaxis. After adherence to a wheat-free diet four children remained symptomless and three experienced one to two anaphylactic reactions.The present results show that wheatω-5 gliadin is a major sensitizing allergen in children with wheat-induced anaphylaxis. They also suggest thatω-5 gliadin IgE ELISA could be used as a diagnostic test for this severe allergy. [ABSTRACT FROM AUTHOR]

Objective: The primary objective was to compare the efficacy of two dosages of bambuterol, a once-daily oral bronchodilator, with placebo in Asian children with asthma. The secondary objective was to assess the tolerability of bambuterol in this population. Design: This was a multicentre, randomised, double-blind, placebo-controlled crossover study, with a run-in period of 2 weeks. The study consisted of three treatment periods of 2 weeks each, separated by washout periods of 2 weeks, with 7 clinic visits in total. Setting: Outpatients were recruited from 10 centres in Indonesia, Malaysia, The Philippines, Singapore and Thailand. Patients: Seventy Asian children aged 6 to 12 years (53 boys and 17 girls) with asthma for at least 6 months were randomised to treatment, and 62 patients completed the study. Interventions: During the three treatment periods, patients received either placebo or 5 or 10mg bambuterol tablets once daily for 2 weeks. Morning peak expiratory flow (PEF) was the primary efficacy variable. Secondary efficacy variables were forced expiratory volume in 1 second (FEV), forced vital capacity (FVC) and diary card data including evening PEF. Results: At baseline, FEV predicted was 82.9% and the reversibility was 22.2%. The study results suggest that the change from baseline in both morning and evening PEF recorded on the diary cards on days 4 to 14 of each treatment period was dose dependent, but only the difference in morning PEF between bambuterol 10mg and placebo was statistically significant (9.1 L/min; 95% confidence interval 0.2 to 18.0 L/min). FEV, FVC, asthma symptom scores and the use of supplementary β-agonists did not differ significantly between placebo and the two bambuterol treatments. Blood pressure and pulse rate remained consistent throughout the study. The number of spontaneously reported adverse events was similar for the three treatment groups. Conclusions: Bambuterol 10mg once daily is an effective bronchodilator in 6- to 12-year-old Asian children in terms of improvement in morning PEF. [ABSTRACT FROM AUTHOR]

Investigates the effects of various forms of heat deliverance on the survival of house-dust mites. Determination of temperature with total mortality; Ineffectivity of sunlight and vacuum-cleaning in removing mites from mats; Comparison between dry and wet heat.

Presents a report of the World Health Organization on the prevention of allergy and asthma. Genetic and environmental influences; Early immunological influences; Predictive and early diagnosis; Preventive measures.