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Biomedical subjects

C K Lai

Publications and source records attributed to C K Lai.

At least 19 recordsLinked to original sources
PubMed1999

Evaluation of the efficacy of a hospital-based asthma education programme in patients of low socioeconomic status in Hong Kong.

BACKGROUND: Good asthma control requires optimal medical treatment in conjunction with appropriate self-management. In the West, the effectiveness of patient education on improving self-management has been well documented. However, data amongst Asian populations are lacking. We performed a pilot study to evaluate the efficacy of a hospital based education programme aimed at improving self-management skills and reducing morbidity in a Chinese population with low socioeconomic status and education level. METHODS: Our asthma education programme was a low-cost programme conducted in essence by specialist respiratory nurses. Patients attending our asthma clinic were instructed during a two-hour educational session on the pathophysiology of asthma, its potential triggers, the appropriate use of medications including proper inhaler techniques, and the self-management of their disease. These instructions were reinforced by video sessions at subsequent outpatient clinic attendance when patients' inhaler and peak flow techniques were checked by the same nurses and their self-management plan re-examined by the attending physicians. Asthma knowledge, inhaler technique, FEV1 and peak expiratory flow (PEF), and patients' self-rating of their asthma were determined at baseline, 6 months and 1 year after the intervention. Morbidity was assessed by the numbers of hospitalizations, unscheduled visits to family physicians and accident and emergency department attendance, courses of oral steroid used and days off work or school at baseline and 1 year. RESULTS: Two hundred and thirty patients were recruited for the study, 83% completing the entire assessment period. The group demonstrated significant improvements in lung function: the mean FEV1 +/- SD increased from 63.6 +/- 20.6% of predicted values at baseline to 68.5 +/- 22.3% at 6 months and 68.6 +/- 22.8% at 1 year (P < 0.05), and the mean PEF +/- SD increased from 64.6 +/- 23.0% of predicted values at baseline to 75.4 +/- 27.0% at 6 months and 76.8 +/- 24.5% at 1 year(P < 0.001). There were also significant improvements in inhaler technique (P < 0.01), asthma knowledge (P < 0.001), patients' self-rating of their asthma (P < 0.05), and reductions in the numbers of hospitalizations (P < 0.01), visits to family physicians (P < 0.001) and accident and emergency department attendance (P < 0.001) during the study period. Patients with moderate to severe asthma as defined by an FEV1 of < 80% of predicted values were most likely to benefit from the programme. CONCLUSIONS: We conclude that patient education is likely to be an essential component in the holistic approach to the management of asthma even amongst Asian populations of low socioeconomic status and education level. Further studies using randomised controlled trials are necessary to consolidate our findings.

Administration, Oral↗
PubMed1999

Transcriptional repression of human hepatitis B virus genes by a bZIP family member, E4BP4.

Box alpha is an essential element of both the upstream regulatory sequence of the core promoter and the second enhancer, which positively regulate the transcription of human hepatitis B virus (HBV) genes. In this paper, we describe the cloning and characterization of a box alpha binding protein, E4BP4. E4BP4 is a bZIP type of transcription factor. Overexpression of E4BP4 represses the stimulating activity of box alpha in the upstream regulatory sequence of the core promoter and the second enhancer in differentiated human hepatoma cell lines. E4BP4 can also suppress the transcription of HBV genes and the production of HBV virions in a transient-transfection system that mimics the viral infection in vivo. Expression of an E4BP4 antisense transcript can, instead, elevate the transcription of the core promoter. A low abundance of E4BP4 protein and mRNA in differentiated human hepatoma cell lines is detected, and E4BP4 is not a major component of box alpha binding proteins in untransfected differentiated human hepatoma cell lines. C/EBPalpha and C/EBPbeta, in contrast, are major components of the box alpha binding activity present in nuclear extracts. E4BP4 has a stronger binding affinity towards box alpha than the endogenous box alpha binding activity present in nuclear extracts. Structure and function analysis of E4BP4 reveals that DNA binding activity is sufficient to confer the negative regulatory function of E4BP4. These results indicate that binding site occlusion is the mechanism whereby E4BP4 suppresses transcription in HBV.

Basic-Leucine Zipper Transcription Factors↗
PubMed1999

Tetrahydropalmatine poisoning: diagnoses of nine adult overdoses based on toxicology screens by HPLC with diode-array detection and gas chromatography-mass spectrometry.

BACKGROUND: Tetrahydropalmatine (THP) is a neuroactive alkaloid with analgesic and hypnotic action. Its analysis is important because cases of human poisonings have emerged as a result of unregulated use of some proprietary biopharmaceuticals containing purified THP. METHODS: We established analytical parameters for HPLC with diode-array detection (HPLC-DAD) and gas chromatography-mass spectrometry (GC-MS) for the detection of THP in serum and urine. Nine acutely THP-poisoned adults were thus screened over 16 months. RESULTS: All patients recovered quickly after mild neurological disturbance. In general, THP was metabolized rapidly and excreted as polar metabolites in urine. Serum THP was measured in five cases and found to be <0.1-1.2 mg/L (<0.3-3.4 micromol/L). Paired analyses of urine with and without glucuronidase treatment clarified the disposition of THP. Our GC-MS method with trimethylsilane derivatization identified O-desmethyl metabolites. With a uniform solid-phase extraction, the HPLC-DAD procedure detected intact glucuronide metabolites. CONCLUSION: Intact glucuronide metabolites of THP are sensitive markers for THP exposures. Our methods and findings provide practical tools and information for surveillance of intoxication caused by excessive THP intake.

Adult↗
PubMed1998

Indoor environment of residential homes in Hong Kong--relevance to asthma and allergic disease.

BACKGROUND: The prevalence of asthma and allergic disease has been increasing in Hong Kong and environmental factors are thought to play a major role. AIM: To define the distribution of common inhaled allergens and air pollutants inside residential homes in Hong Kong. METHODS: Forty randomly selected residential homes were visited and surveyed. Dust samples were collected from mattress, bedroom floor, lounge room floor and kitchen floor for assays of Der p 1, Fel d 1, and Bla g 2. Nitrogen dioxide (NO2) levels were measured by stationary samplers left in the bedroom, lounge room and kitchen over a 1-week period. RESULT: All 40 homes were apartments in high-rise buildings and the mean age of the homes was 7.6 +/- 4.8 years. Visible dampness and mould patches were present in 27.5% of homes and the main fuel for cooking was gas (97.5%). Der p 1, Fel d 1 and Bla g 2 were detectable in at least 1 niche in over 85% of homes. In particular, all dust samples from mattress and bedroom floor contained Der p 1, and over 50% had levels > or = 2 microg/g. The (geometric) mean Der p 1 level in mattress dust was 8.8 (0.3-157.8) microg/g. Fel d 1 and Bla g 2 were present in low levels throughout the homes with respective (geometric) means of 0.3 (0-3.7) microg/g and 0.1 (0-1.1) Unit/g in mattress dust. NO2 was readily detected in all niches but the highest level was in the kitchen with mean exposure of 48.7 ppb which was 1.5 times higher than that in the bedroom and lounge room. CONCLUSION: Major allergens of mite, cat and cockroach, and NO2 are present in varying quantities in residential homes in Hong Kong. Exposure to these environmental factors could be important in the development of asthma and allergic diseases in susceptible individuals.

Air Pollution, Indoor↗
PubMed1998

The interleukin-5 messenger RNA expression in a patient with idiopathic hypereosinophilic syndrome.

Interleukin-5 has a specific role in various eosinophilic activities. It is the predominant cytokine produces by activated T-lymphocytes isolated from patients with idiopathic hypereosinophilic syndrome. We studied a young patient suffering from idiopathic hypereosinophilic syndrome who presented with Horner's syndrome, peripheral neuropathy and skin ulcers. The IL-5 gene expression by CD4+ T-lymphocytes and the peripheral eosinophil count were raised. The skin ulcers continued to deteriorate despite a swift reduction of the IL-5 gene expression and peripheral eosinophil count following systemic corticosteroid treatment. We suggest that peripheral eosinophilia may not be responsible for the damage in skin lesions and more aggressive treatment may be required.

Adrenal Cortex Hormones↗
PubMed1998

Pleural fluid pseudouridine in malignant and benign pleural effusions.

Pseudouridine in urine and plasma has been proved to be a useful tumour marker in many malignant conditions. We studied its usefulness in pleural fluid for distinguishing malignant from non-malignant pleural effusions. Pleural fluid pseudouridine concentrations in different groups of patients with pleural effusion (31 malignant, 29 benign, 16 unknown, 1 double pathology) was measured and compared. Its usefulness in distinguishing malignant from non-malignant pleural effusions was analysed by receiver-operating characteristic (ROC) curve analysis. Pseudouridine concentrations in the malignant group were significantly higher than the non-malignant group (P < 0.017, Bonferroni adjustment) with values overlapping extensively at the lower end. The area-under-the curve (AUC) value in the ROC curve analysis was 0.675 (P < 0.05). We conclude that the pleural fluid pseudouridine is of limited clinical value in distinguishing malignant from non-malignant pleural effusion due to its extensive overlap. However, it is useful when the concentration is higher than 65 mumol/L, which indicates malignancy.

Area Under Curve↗
PubMed1997

Sensitization to inhaled allergens as a risk factor for asthma and allergic diseases in Chinese population.

BACKGROUND: Allergen sensitization is associated with asthma and allergic disease in children, but such a relationship has not been confirmed in Chinese populations. OBJECTIVES: The objective of this study was to evaluate the effects of allergen sensitization and family history of atopy on asthma and allergic disease in Chinese schoolchildren from three southeast Asian populations. METHODS: Written questionnaires on respiratory and allergic symptoms were completed by parents of children of secondary-school age (age range 12 to 18 years) in Hong Kong (n = 1062), Kota Kinabalu in eastern Malaysia (n = 409), and San Bu in southern China (n = 737). A subsample of school-children underwent skin prick testing to common inhalant allergens (Hong Kong 471 children, Kota Kinabalu 321, San Bu 647). RESULTS: The prevalence of asthma and allergic disease in schoolchildren was highest in Hong Kong, intermediate in Kota Kinabalu, and lowest in San Bu. However, the overall rate of atopic sensitization was similar in the three populations (49% to 63%). House dust mite and cockroach were the two most common allergens causing sensitization and these gave rise to more than 95% of the positive skin test results in all three populations. By regression analysis, mite allergy was associated with rhinitis and asthma in all three populations, and a family history of asthma, rhinitis, or eczema was strongly associated with respective symptoms in the subjects. After adjusting for age, sex, atopic status, and family history of allergic disease, the place of residence remained a significant independent factor for asthma (odds ratio [OR] = 1.0 for Hong Kong, 0.57 for Kota Kinabalu, 0.15 for San Bu, p < 0.001), rhinitis (OR = 1.0 for Hong Kong, 0.59 for Kota Kinabalu, 0.15 for San Bu, p < 0.001), or eczema (OR = 1.0 for Hong Kong, 0.35 for Kota Kinabalu, 1.01 for San Bu, p < 0.001). CONCLUSION: Sensitization to indoor allergens was a significant risk factor for asthma and allergic disease, and familial clustering of disease was common in the region. However, the marked difference in disease prevalence in the three southeast Asian populations of Chinese schoolchildren cannot be explained by atopic sensitization and family history alone, and the place of residence was an independent risk factor for asthma and allergies, which suggests an important environmental role in disease pathogenesis.

Adolescent↗
PubMed1997

Non-invasive ventilation in the management of respiratory failure.

Non-invasive positive pressure ventilation (NIPPV) has been used increasingly to treat various forms of respiratory failure, with benefits in terms of gas exchange improvement, avoidance of endotracheal intubation and a decreased mortality. This review will focus on the recent developments and recommendations in the use of NIPPV in the treatment of acute and chronic respiratory failure, the methodology in the application of NIPPV, and briefly on its proposed mechanism of action.

Acute Disease↗
PubMed1997

Hospitalized patients with community-acquired pneumonia in Hong Kong: a randomized study comparing imipenem/cilastatin and ceftazidime.

The aetiology and outcome of hospitalized patients with moderate to severe community-acquired pneumonia (CAP) were evaluated in 60 adult patients (38 male 22 female, mean age 68.4 years). They were randomized for treatment with either ceftazidime or imipenem/cilastatin intravenously for 7 days. Bacteriological diagnoses were made in 25 cases (41.6%): Streptococcus pneumoniae (5), Haemophilus influenzae (5), Pseudomonas spp. in particular Pseudomonas aeruginosa (8), Staphylococcus aureus (4), Chlamydia spp. (2), Mycobacterium tuberculosis (2) and Moraxella catarrhalis (3); mixed organisms were found in 4 patients. Forty-two patients (70%) responded satisfactorily to the regimens with improvement in sputum purulence cough and dyspnoea scores; there was no difference in response between the two groups. Sixteen patients (26.6%) underwent bronchoscopy on day 4 because of inadequate response to the antibiotics regimens, and 9 of them (15%) required a modification of the initial treatment with addition of erythromycin in 5 patients vancomycin in 1 cloxacillin in 1 and antituberculous drugs in 2. Three out of the 60 patients (5%) died of pulmonary sepsis: the aetiological agents were M. tuberculosis in one, Pseudomonas spp./methicillin-resistant S. aureus in another, but were not identified in the third. We conclude that treatment with either ceftazidime or imipenem/cilastatin was efficacious for moderate to severe CAP in Hong Kong.

Adult↗
PubMed1997

Prevalence of asthma and allergy in Hong Kong schoolchildren: an ISAAC study.

Asthma and allergic disease in children is increasing in many Western countries but such trend has not been well-defined in Chinese populations. This paper aims to determine the prevalence of asthma and allergic disease in Hong Kong schoolchildren and compare it with previous data to identify a changing trend. We studied 4,665 schoolchildren aged 13-14 yrs using the International Study of Asthma and Allergy in Childhood (ISAAC) protocol to determine prevalence rates for asthma, wheeze, respiratory symptoms, rhinitis and eczema in 1994-1995. Additional questions on education levels of the parents and smoking status were also asked. Concordance between responses to the written and video questionnaires was good (76% for wheeze ever, 80% for current wheeze). Prevalence rates for asthma ever, wheeze ever, and current wheeze were 11, 20 and 12%, respectively, and were greater in boys (p < 0.05). Rhinitis affected slightly over half of the subjects (52%), and eczema was reported by a sixth (15%), whilst current rhinitis and current eczema were present in 44% and 3.6% of children, respectively. In multiple logistic regression: odds ratio male sex (OR) 1.47; (95% confidence interval (95% CI) 1.15-1.86); current rhinitis (OR 3.00; 95% CI 2.36-3.81); current eczema (OR 2.34; 95% CI 1.40-3.93); and active smoking (OR 2.00; 95% CI 1.38-2.89) were associated with current wheeze; whilst severe wheezing attack was associated with: current rhinitis (OR 2.72; 95% CI 1.47-5.02); current eczema (OR 6.13; 95% CI 2.82-13.33); and active smoking (OR 4.62; 95% CI 2.43-8.76). Age, parental education and passive smoking were not important factors. When compared to previous epidemiological data obtained in 1992, the prevalence rates for asthma ever and wheeze ever had increased by 71 and 255%, respectively, in Hong Kong schoolchildren. The severity of asthma and respiratory symptoms showed a similar increasing trend. Further studies should aim to identify the role of the environment in the pathogenesis of asthma.

Adolescent↗
PubMed1997

Cytokine gene expression profile of circulating CD4+ T cells in active pulmonary tuberculosis.

T lymphocytes, particularly CD4+ cells, are thought to play an important role in the immune defense against Mycobacterium tuberculosis through the release of their wide array of cytokines. In vitro studies suggest that Mycobacterium-specific T-cell clones are of the TH1 subtype. Using the technique of reverse transcription-polymerase chain reaction, we have investigated the capacity for cytokine gene expression profile in ex vivo circulating CD4+ T cells from 20 patients with active pulmonary tuberculosis compared with that of 30 normal healthy tuberculin-positive volunteers. Venous blood samples were collected from the former prior to the initiation of chemotherapy. A significant increase in interleukin (IL-2) expression (p < 0.001) and a significant decrease in IL-5 expression (p < 0.0001) were observed in patients with tuberculosis but no differences were seen in the expression of IL-4 and interferon gamma between the two study groups. Our data support a TH1-like immune response in active tuberculosis.

Adolescent↗
PubMed1997

Effect of anti-DNA autoantibodies on the gene expression of interleukin 8, transforming growth factor-beta, and nitric oxide synthase in cultured endothelial cells.

Our study aims to determine whether anti-dsDNA exerts any effect on the gene expression of IL-8 or TGF-beta in cultured HUVEC. Both cytokines have angiogenic effect on endothelial cells. IgG was purified from 19 patients with SLE and from 19 healthy controls. Anti-dsDNA-depleted polyclonal IgG was also prepared from serum IgG of lupus patients by affinity chromatography with DNA cellulose column. Compared with either control IgG or anti-dsDNA-dep-IgG, HUVEC incubated with anti-dsDNA-containing-IgG expressed higher levels of IL-8 mRNA (p = 0.0001) and TGF-beta 1 mRNA (p = 0.0014). We demonstrated a significant increase in the percentage of cells with fragmented DNA in HUVEC incubated with anti-dsDNA-containing-IgG compared with those incubated with anti-dsDNA-dep-IgG, supporting the notion that anti-dsDNA may exert a direct apoptotic effect on cultured endothelial cells. Our study provides in vitro evidence that anti-dsDNA could play an important pathogenetic role in inducing inflammatory injury of vascular endothelium in SLE.

Adult↗
PubMed1997

Uniform solid-phase extraction procedure for toxicological drug screening in serum and urine by HPLC with photodiode-array detection.

In this HPLC-diode-array detection method for toxicological drug screening, a mixed-mode solid-phase extraction procedure is optimized for isolation of a broad range of drugs from serum and urine. Basic, neutral, and weakly acidic drugs are uniformly recovered. The extract from the solid-phase cartridge is readily injected to a reversed-phase HPLC column for separation by gradient elution. Unknown drugs and metabolites in urine and serum samples from acute drug poisoning cases are rapidly identified by matching their retention times and ultraviolet spectra with hundreds of reference compounds in the library. Urine metabolites of common toxicants from various medications and drugs of abuse are recorded, with their changes of retention times and ultraviolet spectra as related to their metabolic transformations. Glucuronide conjugates of common benzodiazepines, tricyclic antidepressants, and beta-blockers are examined directly without chemical or enzymatic hydrolysis. The system is reliable for diverse clinical investigations of drug overdoses, drug-induced psychoses, and substance abuse.

Blood Chemical Analysis↗
PubMed1997

Prevalence of latex allergy in hospital staff in Hong Kong.

BACKGROUND: The prevalence of latex allergy in healthcare workers in Asian populations is unknown. METHODS: We studied 1472 employees in a teaching hospital in Hong Kong using written questionnaires and 133 respondents underwent skin prick testing to latex glove eluates and common allergens. RESULTS: Glove-related symptoms were common and 455 (30.9%) reported one or more symptoms, the majority of which could be classified as glove dermatitis (GD). On the other hand, symptoms suggestive of latex allergy such as urticaria, rhinitis, wheeze and asthma, were encountered less frequently and were noted by 3.3%. In particular, one developed asthma and two had wheezing, but there was no report of anaphylaxis. A total of 9.9% reported allergic symptoms from contact with other latex devices, in particular, rubber bands, rubber boots, goggles and swimming. Nine subjects (6.8%) had positive skin test to one or more of the five latex extracts. All were atopic to common allergens. Skin test positivity to latex and banana extracts was positively correlated (P < 0.05). In univariate logistic regression, daily glove use, personal history of allergic disease and history of allergic symptoms to latex-containing devices other than gloves were significant risk factors for both GD and LA. Nurses were more likely to complain of GD and workers with positive skin test to latex were 8.6 times more likely to have symptoms of LA. In multiple logistic regression, the remaining significant associations were between history of daily glove use and GD (OR = 50.11, 95% CI 15.88-158.13), and between positive latex skin test and LA (OR = 8.14, 95% CI 1.27-52.36). CONCLUSION: Glove-related symptoms are common in healthcare workers in Hong Kong. Gloved healthcare workers are at risk of becoming sensitized to latex, and those with positive latex skin tests, long glove exposure time and frequent glove changes are at risk of clinical latex allergy.

Adult↗
PubMed1997

Royal jelly consumption and hypersensitivity in the community.

BACKGROUND: Royal jelly consumption has recently been linked with acute asthma, anaphylaxis and death. A cross-sectional survey was conducted to determine the prevalence of and the relationship between royal jelly consumption and hypersensitivity reactions. METHODS: 1472 hospital employees of a teaching hospital in Hong Kong completed a questionnaire on royal jelly consumption and related allergic symptoms, and 176 questionnaire respondents and 300 consecutive asthma clinic patients were skin tested to royal jelly. RESULTS: Royal jelly consumption was high, with 461 out of 1472 subjects (31.3%) having taken royal jelly in the past. A total of nine subjects reported 14 adverse reactions to royal jelly, including urticaria, eczema, rhinitis and acute asthma. Thirteen out of 176 questionnaire respondents (7.4%) and 23 out of 300 consecutive asthma clinic attendees (7.3%) had positive skin test to pure royal jelly. All but one of the 36 subjects with positive royal jelly skin test were atopic to other common allergens. Positive associations were found between positive royal jelly skin test and atopy (OR = 33.73, 95% CI 4.51 to 252.11), adverse reactions to royal jelly and a history of clinical allergy (OR = 2.88, 95% CI 0.72 to 11.58), but not between royal jelly symptoms and previous royal jelly intake. CONCLUSION: Royal jelly consumption is high in the community of Hong Kong. Atopic individuals are at high risk of sensitization to royal jelly but the precise relationship between royal jelly use, positive royal jelly skin test and clinical manifestations of adverse reactions to royal jelly, remains to be defined.

Adolescent↗