PM10 and CO exposure of Hong Kong population in public transit facilities

2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Patterns of soil-transmitted helminth infection and impact of four-monthly albendazole treatments in preschool children from semi-urban communities in Nigeria: a double-blind placebo-controlled randomised trial

Background Children aged between one and five years are particularly vulnerable to disease caused by soil-transmitted helminths (STH). Periodic deworming has been shown to improve growth, micronutrient status (iron and vitamin A), and motor and language development in preschool children and justifies the inclusion of this age group in deworming programmes. Our objectives were to describe the prevalence and intensity of STH infection and to investigate the effectiveness of repeated four-monthly albendazole treatments on STH infection in children aged one to four years. Methods The study was carried out in four semi-urban villages situated near Ile-Ife, Osun State, Nigeria. The study was a double-blind placebo-controlled randomised trial. Children aged one to four years were randomly assigned to receive either albendazole or placebo every four months for 12 months with a follow-up at 14 months. Results The results presented here revealed that 50% of the preschool children in these semi-urban communities were infected by one or more helminths, the most prevalent STH being Ascaris lumbricoides (47.6%). Our study demonstrated that repeated four-monthly anthelminthic treatments with albendazole were successful in reducing prevalence and intensity of A. lumbricoides infections. At the end of the follow-up period, 12% and 43% of the children were infected with A. lumbricoides and mean epg was 117 (S.E. 50) and 1740 (S.E. 291) in the treatment and placebo groups respectively compared to 45% and 45% of the children being infected with Ascaris and mean epg being 1095 (S.E. 237) and 1126 (S.E. 182) in the treatment and placebo group respectively at baseline. Conclusion Results from this study show that the moderate prevalence and low intensity of STH infection in these preschool children necessitates systematic treatment of the children in child health programmes

Soil-Transmitted Helminth Reinfection after Drug Treatment: A Systematic Review and Meta-Analysis

Infections with soil-transmitted helminths (the roundworm Ascaris lumbricoides, the whipworm Trichuris trichiura, and hookworm) affect over 1 billion people, particularly rural communities in the developing world. The global strategy to control soil-transmitted helminth infections is ‘preventive chemotherapy’, which means large-scale administration of anthelmintic drugs to at-risk populations. However, because reinfection occurs after treatment, ‘preventive chemotherapy’ must be repeated regularly. Our systematic review and meta-analysis found that at 3, 6, and 12 months after treatment, A. lumbricoides prevalence reached 26% (95% confidence interval (CI): 16–43%), 68% (95% CI: 60–76%) and 94% (95% CI: 88–100%) of pretreatment levels, respectively. For T. trichiura, respective reinfection prevalence at these time points were 36% (95% CI: 28–47%), 67% (95% CI: 42–100%), and 82% (95% CI: 62–100%); and for hookworm, 30% (95% CI: 26–34%), 55% (95% CI: 34–87%), and 57% (95% CI: 49–67%). Prevalence and intensity of reinfection were positively correlated with pretreatment infection status. Our results suggest a frequent anthelmintic drug administration to maximize the benefit of preventive chemotherapy. Moreover, an integrated control strategy, consisting of preventive chemotherapy combined with health education and environmental sanitation is needed to interrupt transmission of soil-transmitted helminths

Computational fluid dynamic study on the effect of cooling tower plume in an alley of a Mega City

In recent years, cooling towers have become more popular in mega cities mainly because of their superior energy efficiency compared with air-cooled chillers. However, under specific environmental conditions, e.g. the humid air in Hong Kong or the calm wind inside compact built structure, exhausting plume often appears as saturated air (moisture) over cooling towers that adversely affects the visual appearance of the premises. Moreover, visible moist plume arouses public concern due to the possible transport of contaminants or even harmful bacteria such as Legionnella. In this paper, a computational fluid dynamic (CFD) study was performed to examine the mechanism of plume development over cooling towers, the subsequent moisture transport and the resultant impact on the buildings nearby in a hypothetical dense urban environment. The velocity of the cooling tower exhaust is kept constant under different prevalent wind speed. This configuration examines the velocity ratio (v r) at 0.33, 0.83, 1.53 and 2.17 for atmospheric condition of light air, light breeze, gentle breeze and moderate breeze respectively. When the v r is 0.83 and 2.17 (light breeze), the short-circuiting can occur, in which a representative moisture content can reach up to 17.5 and 17.73 gM/kgDA respectively at different distance ratio. This indicates that the discharge air re-enters the cooling tower as some is trapped within the alley. Whilst, as v r increases to 1.53 (gentle breeze), short-circuiting of cooling tower is reduced to approximately by an average of 0.5 gM/kgDA for the specified distance ratio. This is due to the stronger upward draught that pushes the exhaust air further up yet still lingers within the alley. The CFD analysis shows that further increase in the prevalent wind speed suppresses the crosswind mixing of cooling tower exhaust, thus further reduces the chance of short-circuiting. This indicates the environment condition affects the severity of plume. More attention should be pay on the potential risk of public health.link_to_subscribed_fulltex

Reproductive impairment of sea urchins upon chronic exposure to cadmium. Part I: Effects on gamete quality

Successful reproduction is a determining factor for species survival. Pollution may impair reproductive success of adults through effects on gamete quality. Reproductive impairment of the sea urchin Anthocidaris crassispina upon chronic (4 weeks) exposure to 0.01 and 0.1 mg l -1 Cd 2+ was investigated. Criteria used for assessing gamete quality included sperm motility, egg morphology, fertilization rate and dynamics of first cleavage. A dose-response relationship was found between Cd 2+ levels and changes in sperm motility, and percentage fertilization. Sperm motility, measured by computer-assisted sperm analysis, indicated that percent motile sperm, velocities, and percent sperm with normal trajectory were significantly affected by chronic exposure to ≥0.1 mg l -1 Cd 2+. A decline in sperm motility was also accompanied by a decrease in fertilization success of sea urchin sperm. Width/height ratio of sea urchin eggs was not affected by cadmium, but larger egg sizes were found when sea urchins were exposed to 0.1 mg l -1 Cd 2+. Male sea urchins exposed to Cd 2+ produced poorer quality sperm, as indicated by a lower percent fertilization and lower cleavage rate, implying that male sea urchins were more sensitive than females to chronic Cd 2+ exposure. Results of the present study provide an explanation of reproductive impairment in marine invertebrates upon chronic exposure to Cd 2+. Copyright (C) 2000 Elsevier Science Ltd.link_to_subscribed_fulltex

A case of early-onset obesity, hypocortisolism, and skin pigmentation problem due to a novel homozygous mutation in the proopiomelanocortin (POMC) gene in an Indian boy

Proopiomelanocortin (POMC) is the polypeptide precursor of several biologically active melanocortin peptides that have important roles in the regulation of food intake and energy homeostasis, adrenal steroidogenesis, melanocyte stimulation, and immune modulation. Mutation of the POMC gene has been associated with adrenal insufficiency, early-onset obesity, and red hair pigmentation. We describe an Indian boy with secondary hypocortisolism, hyperphagia, early-onset obesity, and skin pigmentation problem. Genetics analysis revealed a novel homozygous mutation in the POMC gene (p.Arg86Term). The boy also had central hypothyroidism in addition to the secondary hypocortisolism. Genetics analysis for the POMC gene should be considered in patients with secondary hypocortisolism, early-onset obesity, and pigmentary problems

ICMPE-8: Dedicated to Professor Rudolf Wu

Special Issue: The 8th International Conference on Marine Pollution and Ecotoxicolog