Aetiology of allergic rhinitis in Hong Kong

ABSTRACTIn a 1993 survey, allergic rhinitis was identified as the most common allergic disease in Hong Kong, affecting 29.1% of schoolchildren. Recently (1995), the International Study of Asthma and Allergies in Childhood (ISAAC) also reported 44.5% current rhinitis among Hong Kong teenagers. Our objective was to study the aetiology of allergic rhinitis in Hong Kong using serological tests of allergen sensitization. In 57 allergic rhinitis patients and in the same number of age- and sex-matched controls the following were measured: serum total IgE, mixed aeroallergen IgE (Phadiatop™) and specific IgE versus house dust mite (HDM), cockroach, cat and dog dander, mould mixture (Penicillium, Cladosporium, Aspergillus and Alternaria species) and four local pollens (Bermuda grass, Timothy, ragweed and mugwort). Compared with controls, allergic rhinitis patients (26 males, 31 females; mean (± SD) age 25 ±11 years) had a significantly elevated serum total IgE concentration (mean ± SEM: 496 ± 88 vs 179 ± 38 kU/L) and an increased proportion of positive Phadiatop (95 vs 33%) and specific IgE tests versus HDM (90 vs 44%) and cockroach (42 vs 9%; Mann-Whitney U-test and χ2 tests all P < 0.005). There was no significant difference in sensitization to other allergens tested. House dust mite and cockroach are ubiquitous in Hong Kong with a warm, humid climate and crowded living conditions. Their identification as aetiological agents of allergic rhinitis should help in the development of environmental strategies for reducing the inhalant allergen load to prevent and control this prevalent and costly health problem in our community

Growth and fatty acid production of thraustochytrids from Panay mangroves, Philippines

Optimization of culture conditions with regard to the combined effects of salinity and temperature on biomass and fatty acid production of four thraustochytrid isolates were undertaken. Two strains of Schizochytrium mangrovei (IAo-1 and IXm-6), and one isolate each of Schizochytrium sp. (BSn-1) and Thraustochytrium sp. (IRa-8), isolated from fallen mangrove leaves, were used in this study. Results of the physiological study show that the best growth condition for Schizochytrium isolates was at a salinity range of 15-30 ‰ at 20-30°C, while that for Thraustochytrium sp. was at 22.5-30 ‰ at 25°C. Highest biomass production was 350 mg 50 mL-1 for Schizochytrium spp., and 133 mg 50 mL-1 for Thraustochytrium sp. Total lipid content (% freeze-dried biomass) ranged from 16.0-33.2% for S. mangrovei, 13.0-39.1% for Schizochytrium sp., and 11.4-37.5% for Thraustochytrium sp. Highest lipid production was observed at 15-22.5 ‰ salinity (25°C) for S. mangrovei, and at 15 ‰ (25°C) for Schizochytrium sp. and Thraustochytrium sp. Palmitic acid (16:0) and docosahexaenoic acid (DHA; 22:6n3) were the major components of the total fatty acid (TFA) content, comprising about 39-42% and 24-35%, repectively.This study was jointly funded by the Aquaculture Department, Southeast Asian Fisheries Development Center (study code Nr-05-F99T) and the Department of Biology and Chemistry, City University of Hong Kong