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Biomedical subjects

M Chan-Yeung

Publications and source records attributed to M Chan-Yeung.

At least 19 recordsLinked to original sources
PubMed2006

Disturbance of systemic antioxidant profile in nonsmall cell lung carcinoma.

The present study aimed to determine the alterations of antioxidant activities in erythrocytes from patients with nonsmall cell lung carcinoma (NSCLC). A comparative study of the systemic antioxidant activities in red blood cell lysate from subjects with NSCLC and healthy control subjects was conducted. The antioxidants catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured using chemical kinetic reactions under spectrophotometry. In total, 189 cases of mostly advanced-stage IIIB or stage IV NSCLC and 202 healthy controls were studied. In subjects with lung cancer, there was similar catalase activity, lower SOD activity (median (interquartile range) 13.4 (9.0-27.2) versus 48.7 (27.0-64.3) U x (ghaemoglobulin(Hb)(-1)), and higher GPx activity (175.2 (126.6-288.3) versus 49.2 (39.5-59.2) mU x (gHb)(-1)) compared with controls. The antioxidant activities in lung cancer subjects were not associated with age, sex, smoking status, or tumour cell types. However, more advanced disease (stage IV compared with stage IIIB) was associated with lower SOD activity. Using multivariable analysis, the presence of lung cancer independently predicted SOD and GPx activities. In conclusion, nonsmall cell lung carcinoma in Chinese subjects is associated with alterations in systemic antioxidant activities, which may play an important role in carcinogenesis.

Adult↗
PubMed2006

Prevalence and trend of self-reported asthma and other allergic disease symptoms in Morocco: ISAAC phase I and III.

BACKGROUND: The prevalence of asthma and other allergic diseases is increasing in many parts of the world. OBJECTIVE: To determine the prevalence of asthma, rhinoconjunctivitis and skin allergy symptoms in Morocco as part of the International Study of Asthma and Allergic Diseases in Children (ISAAC). METHODS: The survey was conducted using the standardised method of ISAAC Phase III in four centres in Morocco-Casablanca, Marrakech, Ben Slimane and Boulmane-with respectively 1777, 1689, 1008 and 1254 13-14-year-old schoolchildren participating. A comparison of the results with ISAAC Phase I was carried out in two centres. RESULTS: The prevalence of self-reported symptoms of wheeze in the last 12 months (6.4-16.2%), nasal symptoms (27.9-52.8%), rhinoconjonctivitis (8.8-28%) and eczema (13.3-20.2%) varied between centres, and were highest in Casablanca, the largest city in Morocco. Significant increases in almost all symptoms were found in the two centres of Casablanca and Marrakech between ISAAC Phase I and Phase III. CONCLUSION: Morocco could be classified as a country with an intermediate burden of asthma (between 10% and 15%) and other allergic disorders. The prevalence of these symptoms has increased in the past 5 years.

Adolescent↗
PubMed2006

Management of childhood asthma.

The guidelines for the management of childhood asthma have evolved from recommendations by experts to being evidence-based as a result of better understanding of the pathophysiology of asthma, awareness of the heterogeneity and early onset of childhood asthma and a new approach to the pharmacological management. While there are reasonably good evidence-based guidelines for the treatment of asthma in children aged over 5 years, there is a paucity of data for preschool children for the most appropriate management. Most guidelines include recommendations on diagnosis of asthma in children and pharmacological treatment according to the severity of the asthma. Environmental control is an important cornerstone of care, and allergen avoidance should be recommended for children with asthma who are known to be sensitised to the allergen. Environmental tobacco smoke remains an important trigger for worsening asthma in all children, and their parents must be encouraged to give up the habit. Educating children with asthma and their care givers on the disease and proper treatment is another vital element in the management of asthma. There remains a major problem with ensuring the implementation of guidelines in most countries. A care gap thus exists between best practice and common practice. The impact on asthma morbidity of developing and implementing guidelines requires appropriate study.

Asthma↗
PubMed2006

Prevalence and determinants of positive tuberculin reactions of residents in old age homes in Hong Kong.

OBJECTIVE: To determine the prevalence of tuberculous infection and the predictors of positive tuberculin reactivity in old age home residents in Hong Kong. DESIGN: Cross-sectional study. METHODS: A questionnaire-interview and review of medical records were carried out, together with measurement of weight and height/arm span and assessment of nutritional status. A one-stage tuberculin skin test (TST) was performed using two units of PPD RT23. An induration > or = 10 mm was considered as positive. RESULTS: Of 3682 residents (71.7% participation, mean age 82 years) who agreed to undergo a TST, 46.3% had a positive reaction. Factors associated with a significantly higher risk of a positive TST included being male, an ex- or current smoker and having a past history of tuberculosis (TB). Factors associated with reduced positive tuberculin reactivity included older age groups (> 70 years), a history of cancer and chronic obstructive pulmonary disease and low body mass index quartiles. CONCLUSION: In old age homes, the high prevalence of latent tuberculous infection is responsible for the high rate of active TB due to reactivation. Early diagnosis and treatment are necessary to prevent transmission of disease in these crowded environments with susceptible individuals.

Age Factors↗
PubMed2005

Inhaled fluticasone in bronchiectasis: a 12 month study.

BACKGROUND: The clinical efficacy of inhaled corticosteroid (ICS) treatment has not been evaluated in bronchiectasis, despite the presence of chronic airway inflammation. METHODS: After three consecutive weekly visits, 86 patients were randomised to receive either fluticasone 500 mug twice daily (n = 43, 23F, mean (SD) age 57.7 (14.4) years) or matched placebo (n = 43, 34F, 59.2 (14.2) years) and reviewed regularly for 52 weeks in a double blind fashion. RESULTS: 35 and 38 patients in the fluticasone and placebo groups completed the study. Significantly more patients on ICS than on placebo showed improvement in 24 hour sputum volume (OR 2.5, 95% CI 1.1 to 6.0, p = 0.03) but not in exacerbation frequency, forced expiratory volume in 1 second, forced vital capacity, or sputum purulence score. Significantly more patients with Pseudomonas aeruginosa infection receiving fluticasone showed improvement in 24 hour sputum volume (OR 13.5, 95% CI 1.8 to 100.2, p = 0.03) and exacerbation frequency (OR 13.3, 95% CI 1.8 to 100.2, p = 0.01) than those given placebo. Logistic regression models revealed a significantly better response in sputum volume with fluticasone treatment than with placebo among subgroups of patients with 24 hour sputum volume <30 ml (p = 0.04), exacerbation frequency </=2/year (p = 0.04), and sputum purulence score >5 (p = 0.03). CONCLUSIONS: ICS treatment is beneficial to patients with bronchiectasis, particularly those with P. aerurginosa infection.

Administration, Inhalation↗
PubMed2004

The burden and impact of COPD in Asia and Africa.

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. The World Health Organization (WHO) estimated that COPD is currently the seventh leading cause of death and disability worldwide, but will rise to the fifth position by 2020. The estimated prevalence of COPD worldwide in 2001 was 1013/100,000 population; it was highest in the Western Pacific Region and lowest in Africa. The mortality from COPD followed the same pattern. The prevalence of smoking is slowly decreasing in the industrialised world and rising in developing countries, especially in Asia and Africa. Cigarette consumption per adult has also decreased in the Americas, remained the same in Europe but increased in all other regions, especially the Western Pacific. Indoor air pollution from combustion of biomass/traditional fuels and coal, previous tuberculous infection, outdoor air pollution and childhood respiratory infections are other important risk factors for COPD in developing countries. The rise in morbidity and mortality from COPD will be most dramatic in Asian and African countries over the next two decades, mostly due to progressive increase in the prevalence of smoking. As developing countries can ill afford the added economic burden of COPD and other smoking-related diseases, there is an urgent need for multi-dimensional actions in reducing the main risk factor of cigarette smoking.

Adult↗
PubMed2004

Candidate genetic polymorphisms for asthma in Chinese schoolchildren from Hong Kong.

BACKGROUND: Polymorphisms in several genes have been associated with asthma, atopy and bronchial hyperresponsiveness in white and Japanese populations. In this study we tested for associations of 11 polymorphisms with wheeze and asthma in 10-year-old Chinese schoolchildren. METHODS: The subjects were 107 children who had wheeze in the last 12 months and 118 without wheeze in the last 12 months. They were randomly selected from 3110 children who took part in Phase II of the International Study of Asthma and Allergies in Childhood. These schoolchildren underwent questionnaire, spirometry and methacholine challenge testing. RESULTS: The A allele of the tumor necrosis factor-alpha (TNFA) G-308A polymorphism was significantly associated with wheeze in the last 12 months (odds ratio [OR] 2.1, P = 0.04) and current asthma (OR 2.6, P = 0.006). When stratified by gender, these associations were only seen in the female study participants. In girls, the OR for the TNFA-308A allele and wheeze in the last 12 months was 3.6 (P = 0.01) and for current asthma it was 6.0 (P = 0.0006). CONCLUSION: The A allele of the TNFA G-308A polymorphism was a risk factor for asthma-related phenotypes in girls but not boys.

Asian People↗
PubMed2004

Management of chronic obstructive pulmonary disease in Asia and Africa.

This review examines whether the comprehensive programme recommended by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), developed mostly by physicians in industrialised countries, can be applied in developing countries. In developing countries, there are several major limitations to the implementation of the programme. First, management of chronic obstructive pulmonary disease (COPD) patients is not a priority in competing for health care resources. Second, only major medical centres in developing countries have spirometers; the reliance on spirometric testing for diagnosis, staging and treatment options, as recommended by the GOLD guidelines, makes it almost impossible for the programme to be implemented. Third, in many Asian and African countries, regular monitoring is often restricted to patients with severe COPD who have frequent hospitalisations or clinic visits for exacerbations and complications. Fourth, the choice of therapy usually depends on the availability and cost of drugs. Finally, given the aetiological role of sequelae of lung infections, including tuberculosis, the appropriateness and safety of using intermittent courses of oral steroids during acute exacerbations and of long-term, high-dose inhaled corticosteroids for moderate to severe COPD in developing countries has not been evaluated. Developing countries in Asia and Africa may need to adapt the GOLD guidelines according to varying aetiology, local health care resources, socio-economic and cultural factors and development of health services. Prevention programmes, especially for tobacco control, are of paramount importance. National and international efforts must be directed towards controlling the tobacco epidemic in developing countries to reduce the burden of COPD and other tobacco-induced diseases.

Africa↗
PubMed2004

Lymphoepithelioma-like carcinoma of the lung: experience with ten cases.

OBJECTIVE: Lymphoepithelioma-like carcinoma of the lung (LELC) is a rare form of non-small cell lung cancer predominantly affecting young non-smoking Asians, and there has been only limited experience in its palliative chemotherapy and radiotherapy. We investigated tumour response, time to progression and survival of LELC patients who received such treatment. DESIGN: We prospectively recruited patients with confirmed advanced LELC who were treated with chemoradiotherapy in our unit, a regional tertiary referral centre for lung cancer treatment. RESULTS: There were 10 patients (five males, age 47 +/- 9.8 years, median follow-up 22 months) with advanced LELC (respectively 1, 4, and 5 patients at TNM stage IIIA, IIIB and IV) who received systemic chemotherapy and radiotherapy. The primary chemotherapy regimen consisted of 5-fluorouracil/leucovorin/cisplatin. The response rates to 5-fluorouracil/leucovorin/cisplatin were 60% partial response, 10% stable disease, and 30% progressive disease. Eight patients were also given local radiotherapy. Five patients received salvage chemotherapy when disease progressed after primary chemotherapy. The overall median survival was 23.4 +/- 4.7 months. CONCLUSION: The encouraging response to combination chemotherapy with 5-fluorouracil/leucovorin/ cisplatin, although empirical, supports its use with radiotherapy in unresectable lymphoepithelioma-like carcinoma of the lung.

Adult↗
PubMed2004

Pentaglobin in steroid-resistant severe acute respiratory syndrome.

SETTING: The treatment of severe acute respiratory syndrome (SARS) is at best controversial, although there is considerable anecdotal experience to show the benefits of corticosteroid therapy for selected patients. Some patients deteriorate relentlessly despite treatment with antibiotic, corticosteroid and mechanical ventilation. OBJECTIVE: To attempt to determine the clinical efficacy of pentaglobin, an IgM-enriched immunoglobulin preparation, on 12 severe SARS patients who continued to deteriorate despite corticosteroid and ribavirin therapy. DESIGN: Retrospective analysis of daily quantitative and radiographic data on the cohort in a regional teaching hospital. RESULTS AND CONCLUSION: There was significant improvement in radiographic scores, when compared with day 1, on days 5, 6 and 7 (P < 0.05) after commencement of pentaglobin treatment. Similarly, there was significant improvement in oxygen requirement, when compared with day 1, on days 6 and 7 (P < 0.05) after commencement of pentaglobin treatment. There were no reported adverse events attributable to pentaglobin administration. Ten patients made an uneventful recovery after treatment. One elderly man died from cardiorespiratory arrest despite clinical and radiological improvement, and another patient is making good progress. Pentaglobin is safe and probably effective in the treatment of steroid-resistant SARS. A double-blind placebo-controlled study should therefore be considered.

Adrenal Cortex Hormones↗
PubMed2003

Genetic variants of the IL13 and IL4 genes and atopic diseases in at-risk children.

We studied a cohort containing 368 children at high risk of developing atopy and atopic disorders and 540 parents of those children to investigate whether the IL13 Arg130Gln and C-1112 T polymorphisms were associated with these outcomes. We also investigated whether haplotypes consisting of any two polymorphisms of IL13 Arg130Gln, IL13 C-1112 T and IL4 C-589 T were associated with these phenotypes. In 288 white children, the IL13 130Gln allele was associated with atopy (RR=1.9, P=0.047), and with atopic dermatitis (RR=2.5, P=0.014). The associations were confirmed using a family-based test of association (P=0.027 and 0.030, respectively) in all subjects. In white subjects there were associations of haplotypes consisting of IL13 Arg130Gln and IL4 C-589 T with atopic dermatitis (P=0.006) and with atopy (P=0.009). Our data suggest that the IL13 Arg130Gln polymorphism and haplotypes consisting of IL13 Arg130Gln and IL4 C-589 T were associated with the development of atopy and atopic dermatitis at 24 months of age.

Asian People↗
PubMed2003

Tuberculosis in Hong Kong-patient characteristics and treatment outcome.

OBJECTIVES: To identify the general characteristics of patients with tuberculosis, and to evaluate their treatment outcomes. DESIGN: Retrospective study. SETTING: Tuberculosis and Chest Service, Department of Health, Hong Kong. SUBJECTS AND METHODS: All patients with tuberculosis registered for treatment from 1 January 1996 to 31 December 1996 were included in the study. Information was extracted from their medical records at treatment commencement and at 12 and 24 months after treatment was instigated. Data gathered included demographic data, past treatment, site of disease, case category, treatment regimen, bacteriological status, and treatment outcome. RESULTS: There were 5757 patients for analysis. Approximately one third of patients were aged 60 years or older, and 69.1% were male. Pulmonary disease alone occurred in 77.7% of patients, while both pulmonary and extrapulmonary diseases occurred in 8.6%. New patients comprised 84.6% of cases, and 16.3% had concomitant illnesses. There was excess risk of disease among patients who were male, elderly, or who had silicosis. Only 0.1% of patients were co-infected with human immunodeficiency virus infection. Among the 5757 cases evaluated, 1324 (23.0%) were new patients with a positive sputum smear, 299 (5.2%) were patients who were retreated with a positive sputum smear, and 4134 (71.8%) were new or retreatment patients with a negative sputum smear. The overall treatment completion rates at 12 and 24 months were 80.4% and 84.8%, respectively. Males and patients aged 60 years or older had lower treatment completion rates. Non-adherence, transfer to other services, and mortality among the elderly were key factors influencing treatment outcomes. Co-morbidity was associated with better case-holding, and this more than compensated for its effect on prolongation of treatment and mortality. CONCLUSIONS: There was an excess risk of tuberculosis among male and elderly patients, who also had a less favourable outcome. Active screening of clearly identified risk groups may be appropriate but requires the completion of more in-depth studies and careful cost-effectiveness analyses. Further efforts with respect to case-holding are indicated to address treatment defaulting and transfer rates.

Adolescent↗
PubMed2003

Prevalence and predictors of default from tuberculosis treatment in Hong Kong.

OBJECTIVE: To determine the prevalence and risk factors of default from tuberculosis treatment in Hong Kong. DESIGN: Retrospective study. SETTING: Data were obtained from programme forms completed by physicians in the Hong Kong Government Tuberculosis and Chest Service and from medical records from Hong Kong chest clinics. PATIENTS: In all, 5917 patients registered for antituberculous drug therapy in 1996; medical records of 5757 patients were reviewed. MAIN OUTCOME MEASURES: Patients who defaulted treatment were defined as those who had failed to collect medication for more than 2 consecutive months after the date of the last attendance during the course of treatment. Demographic and clinical characteristics, including history, treatment, and outcome, were compared between defaulters and non-defaulters, both among the whole group and among those with pulmonary disease. RESULTS: There were 442 (8%) patients who defaulted from treatment. Forty-five percent of those who defaulted did so in the first 2 months of treatment. Key risk factors associated with non-compliance were a history of default, male sex, and a history of concomitant liver disease or lung cancer. Among patients with pulmonary tuberculosis (381 defaulters and 1537 non-defaulters), multiple drug resistance was also associated with default from treatment. Among defaulters with pulmonary disease, 39% were still bacteriologically positive at the time of default. CONCLUSION: Default from treatment may be partially responsible for the persistent high rates of tuberculosis in Hong Kong in the past decade. Health professionals should ensure that all barriers to treatment be removed and that incentives be used to encourage treatment compliance.

Antitubercular Agents↗
PubMed2003

Severe acute respiratory syndrome.

Severe acute respiratory syndrome (SARS) is a new disease that poses a threat to international health. The SARS epidemic earlier this year affected more than 30 countries and regions, with a cumulative global total of 8098 cases. It is caused by a novel coronavirus, probably of animal origin. The mean incubation period is 6.4 days (range 2-11 days). Patients usually present with high fever, chills, myalgia and dry cough, with or without chest X-ray evidence of pneumonia at the onset of disease. A history of contact with or travel to an area with local transmission is common. Diagnosis is based on clinical criteria, as a valid rapid diagnostic test is not yet available. There is no specific antiviral therapy for this disease, and no controlled clinical trial for any treatment modality has been conducted. In several retrospective studies steroids have been shown to be useful in a proportion of patients who deteriorated despite antibiotics and supportive treatment. SARS has a high morbidity (about 25% required intensive care) and fatality (9.6%). A high index of suspicion for the disease, isolation of patients, strict observation of infection control practices and compliance with use of personal protective equipment are necessary to prevent nosocomial infection. Contact tracing and quarantine are essential measures to prevent community spread of disease. Prevention of future outbreaks requires strengthening of infection control practices in hospitals, development of a rapid diagnostic test and a vaccine, and removal of any animal reservoir and environmental conditions that led to the spread of the disease.

Adolescent↗
PubMed2002

Occupational and environmental risk factors for respiratory symptoms in rural Beijing, China.

The aim of the present study was to determine the effects of occupational and environmental exposure on respiratory symptoms in adults in rural Beijing, China. Thirty randomly selected villages in the counties of Shunyi and Tongxian, 50 km north and east, respectively, of the city of Beijing, China, participated in this study. Village doctors interviewed all residents aged > or = 15 yrs and completed the International Union Against Tuberculosis and Lung Disease Questionnaire on Bronchial Symptoms translated into Chinese with added questions on smoking and occupational and environmental exposure. Of the eligible population, 22,528 adults (98%) took part. The prevalence of all respiratory symptoms, i.e. asthma-like symptoms, asthma attacks in the last 12 months, chronic cough and chronic phlegm, was low. Significant determinants for respiratory symptoms were age, sex, smoking and county of residence. A dose-dependent relationship was found between cumulative cigarette consumption and prevalence of respiratory symptoms. After adjusting for these variables, exposure to insecticides and fertilisers significantly increased the risk of most of the respiratory symptoms, whereas exposure to indoor air pollution from domestic fuels did not. Exposure to chemicals such as insecticides and fertilisers contributed independently to the risk of respiratory symptoms in rural Beijing, China.

Adolescent↗
PubMed2002

The prevalence of asthma and asthma-like symptoms among adults in rural Beijing, China.

No data have been reported on the prevalence of asthma in rural areas of China. The objective of the present study was to determine the prevalence of asthma-like symptoms, reported asthma and reported asthma attacks in rural Beijing, China, and to compare the prevalence in 20-44-yr-old participants with those reported for Canada and the European Community Respiratory Health Survey (ECRHS). For a cross-sectional survey, 30 villages were randomly selected in the counties of Shunyi and Tongxian, 50 km north and east respectively of the city of Beijing and within the municipality of Beijing. The International Union Against Tuberculosis and Lung Disease questionnaire on bronchial symptoms translated into Chinese was completed by village doctors for each individual of >15 yrs. The survey was completed by 22,561 individuals, representing 98% of the eligible population. The prevalence of asthma-like symptoms and reported asthma attacks was higher in females than in males and increased with age. Smoking significantly increased the prevalence of symptoms; the effect in females was greater than in males. Among the 20-44-yr-olds, the prevalence of reported asthma attacks in the previous 12 months was 0.67% in rural Beijing, very much lower than that reported in ECRHS centres (3.1%), urban Canada (6.9%) and semirural Canada (5.1%), after adjusting for age and sex. The prevalence of asthma-like symptoms was also very low in rural Beijing compared with ECRHS centres and Canada. It is concluded that the prevalence of asthma-like symptoms and reported asthma was low in rural China compared with other countries, consistent with reports of the relative scarcity of asthma in farms and the "hygiene hypothesis".

Adolescent↗