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Biomedical subjects

W K Lam

Publications and source records attributed to W K Lam.

At least 73 records · Page 4Linked to original sources
PubMed1999

A comparative study on the efficacy of levofloxacin and ceftazidime in acute exacerbation of bronchiectasis.

A prospective randomized study was performed in order to compare the efficacy of oral levofloxacin, a new S- isomer of ofloxacin, with intravenous ceftazidime in the empirical treatment of acute exacerbations of bronchiectasis. Consecutive patients with acute exacerbation of bronchiectasis were recruited at a tertiary referral centre and were randomized to receive 10 days' treatment with either oral levofloxacin (300 mg b..d.) or ceftazidime (1 g i.v.t.d.). Body temperature, cough score, dyspnoea score, sputum purulence and volume and white blood cell and neutrophil count were assessed on day 1 and day 10. Thirty-five patients (mean age 61 yrs, 15 males) completed the study; 17 of these were in the levofloxacin group. There was no significant difference in the distribution of sputum pathogens or clinical parameters between the two groups at entry to and completion of the study. Both groups of patients showed significant improvement in 24-h sputum volume, sputum purulence score, cough score and dyspnoea score (p<0.001) but there was no significant difference between these two groups at entry to or on completion of the study (p>0.05). The results of this study suggest that oral administration of levofloxacin is as effective as parenteral ceftazidime in the empirical treatment of exacerbations in bronchiectasis.

Acute Disease↗
PubMed1999

Helicobacter pylori and upper gastrointestinal symptoms in bronchiectasis.

The recently reported increase in seroprevalence of Helicobacter pylori, the causative pathogen in peptic ulceration, in bronchiectasis is unexplained. Therefore, the association of antibodies directed against cytotoxin-associated gene A(CagA), whose expression indicates virulence of H. pylori, and upper gastrointestinal symptoms in patients with stable bronchiectasis and healthy volunteers evaluated. One hundred patients (mean +/- SD age 55.1+/-16.7 yrs) and 94 healthy asymptomatic subjects (54.6+/-7.6 yrs) underwent clinical and physiological assessment and serum levels of anti-H. pylori CagA were determined using standard clinical and enzyme-linked immunosorbent assay techniques. Samples were positive for anti-H. pylori CagA in 11.7% of controls and 24% of bronchiectatic subjects (p = 0.03). There was, however, no association between serum H. pylori CagA immunoglobulin G level and forced expiratory volume in one second (FEV1), forced vital capacity (FVC), sputum volume, respiratory symptoms or upper respiratory gastrointestinal symptoms (p>0.05). Patients who suffered from acid regurgitation or upper abdominal distension had significantly lower FEV1 and FVC (as a percentage of the predicted value) compared to their counterparts. The results of anticytotoxin-associated gene A measurements in this study contrasted with the previous finding that anti-Helicobacter pylori immunoglobulin G correlated with sputum volume. These findings, therefore, suggest that Helicobacter pylori, should it have a pathogenic role in bronchiectasis, could act via noncytotoxin-associated gene A-mediated mechanisms, and, in this context, gastro-oesophageal reflux might be of importance in bronchiectasis.

Adult↗
PubMed1999

Chemotherapy for advanced non-small-cell lung cancer: role of paclitaxel and gemcitabine.

OBJECTIVE: To review the role of chemotherapy in advanced non-small-cell lung cancer, focusing on cisplatin-based regimens and two new drugs: paclitaxel and gemcitabine. DATA SOURCES: Medline search of the relevant English literature. STUDY SELECTION: Open and randomised comparative (phases II and III2) studies, and meta-analyses of cytotoxic drugs/regimens used to treat advanced non-small-cell lung cancer. DATA EXTRACTION: The following factors were studied and compared: symptomatic response rates; tumour response rates: median survival time and 1-year survival rates; and side effects of cisplatin-, paclitaxel-, and gemcitabine-based regimens. DATA SYNTHESIS: Using cisplatin-based chemotherapy achieves significant relief of disease-related symptoms of advanced non-small-cell lung cancer and a slight improvement in the median survival time (by approximately 1.5 months). New cytotoxic drugs that are effective and have good safety profiles include paclitaxel and gemcitabine. When used as single agents, these two drugs give response rates of approximately 25%. When used with cisplatin/carboplatin, response rates increase to 45% to 62% and 1-year survival rates increase to 40% to 60%. CONCLUSION: Paclitaxel, gemcitabine, and other drugs such as decetaxel and vinorelbine are promising new chemotherapeutic agents in the treatment of advanced non-small-cell lung cancer. These drugs can palliate disease symptoms and improve the median survival time. The optimal dose and treatment schedules, however, are yet to be defined.

Journal Article↗
PubMed1998

Biochemical separations by continuous-bed chromatography.

Innovations in column-packing media for biomolecule purification have progressed from large spherical, porous polysaccharide beads to advanced polymeric supports. Continuous-bed technology is a radical new technology for chromatography based on the polymerization of advanced monomers and ionomers directly in the chromatographic column. The polymer chains form aggregates which coalesce into a dense, homogeneous network of interconnected nodules consisting of microparticles with an average diameter of 3000 A. The voids or channels between the nodules are large enough to permit a high hydrodynamic flow. Due to the high cross-linking of the polymer matrix, the surface of each nodule is nonporous yet the polymeric microparticles provide a very large surface area for high binding capacity. This paper will demonstrate the properties and advantages of using a continuous bed support for high resolution biomolecule separations at high flow-rates without sacrificing capacity.

Animals↗
PubMed1998

Management of non-small cell lung cancer according to staging--an update.

The treatment of non-small cell lung cancer (NSCLC) depends on staging based on tumour (T), nodal (N) and metastasis (M) descriptors. Stages I and II tumours are potentially curable with surgery alone. Stage IIIA T3 tumours are also potentially operable. Preoperative chemotherapy appears promising in downstaging stage IIIA disease to enable surgical resection. Recent meta-analyses did not support the use of postoperative chemotherapy for stages I, II and IIIA diseases, but were supportive of the use of cisplatin-based chemotherapy in stage IIIA N2 disease (+ radiotherapy), stage IIIB disease (+ radiotherapy) and in metastatic stage IV disease in improving survival. New chemotherapy agents available over the past few years would further improve the efficacy of chemotherapy in NSCLC.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Kartagener's syndrome: a re-visit with Chinese perspectives.

The objective of this study was to evaluate the clinical, radiological investigation profiles, and ciliary function and ultrastructure in Chinese patients with Kartagener's syndrome (presence of dextrocardia, sinusitis and bronchiectasis). All patients with dextrocardia were assessed for the presence of sinusitis and bronchiectasis in our hospital network. Patients identified with Kartagener's were assessed when they were at steady state for their bronchiectasis. Seven cases (4 males; mean age 34.9 years) were identified and systematically reviewed. The mean 24 h sputum volume was 26.6 +/- 32.77 mL/day and the patients suffered from a mean of 2.9 exacerbations/year. Nasal symptoms (anosmia in one, obstruction in six and persistent discharge in three patients) were common. Only two cases (1 M) were married and both had normal fertility. Lung function assessment showed a mean FEV1/FVC of 83.3 +/- 38.78/86.5 +/- 36.72 (% predicted) with little reversibility. High resolution computerized tomography (HRCT) revealed bronchiectactic involvement of the lower lobes in seven and middle lobe/lingula in four cases. Assessment of alpha-1-anti-trypsin, aspergillus precipitins, auto-antibodies and serology for Pseudomonas pseudomallei was normal. Sputum culture yielded Pseudomonas aeruginosa in three, Haemophilus influenzae in three and commensals in one case. Phase contrast microscopy assessment of respiratory cilia, obtained by brushing the inferior turbinate, revealed that most of the mucosa was unciliated. The mean ciliary beat frequency was 5.2 +/- 6.76 Hz (range 0-13.7; normal range 12-18 Hz). Four patients had immotile cilia whilst the rest had normal ciliary movement. Transmission electron microscopy showed the absence of dynein arms in four patients. The results of this study show that patients with Kartagener's syndrome may have normal ciliary ultrastructure and the absence of dynein arms is not necessarily associated with ciliary immotility. The presence of ciliary immotility might have prognostic value as these patients appear to have more active bronchiectasis. Our experience on this series should help clinicians in the investigation and management of these patients.

Adolescent↗
PubMed1998

Chemotherapy for advanced (stage IIIB and stage IV) non-small cell lung cancer: the Hong Kong perspective.

Non-small cell lung cancer (NSCLC) accounts for about 80% of all primary lung cancers, and 60% of cases present as advanced stages IIIB and IV disease. Traditionally, treatment of stages IIIB and IV disease was only symptomatic (including radiotherapy) and supportive care, and cytotoxic chemotherapy was relatively ineffective. Our initial clinical trials, using MACC, FuAM, FAM, Hi-FAM and cisplatin-VP16, gave response rates of 5-20% and a stabilization rate of 7-25%, with no impact on median survival. Our most recent chemotherapy regimen MIP (mitomycin-C, ifosfamide and cisplatin) proved to be more effective with a 44% response rate and a 28% stabilzation rate, and produced a significantly longer median survival (32 weeks) than best supportive care alone (19.5 weeks, P< 0.05). The response rate further increased to 62.5% with dose intensification and GM-CSF support. Chemotherapy can now be recommended to motivated, well-informed patients with good performance status in institutions with experience in cancer chemotherapy on a protocol basis. The most recent addition of new effective cytotoxic agents such as paclitaxel, docetaxel, gemitabine and vinorelbine gave promising results in NSCLC, and optimal combinations and dose schedules are being defined by multicentred studies.

Antineoplastic Agents↗
PubMed1998

Clinical profiles of Chinese patients with diffuse panbronchiolitis.

BACKGROUND: Diffuse panbronchiolitis (DPB), characterised by progressive sinobronchial sepsis, is well characterised in Japanese subjects but not in other ethnic groups. The experience with DPB in seven Chinese patients is described and the clinical profiles compared with those of Japanese subjects. METHODS: Seven Chinese patients (three women; mean (SD) age 48(18.6) years, all never smokers) who attended a teaching hospital centre and fulfilled the diagnostic criteria for DPB were assessed prospectively for clinical, radiological, lung function, microbiological, and other "characteristic" laboratory parameters. RESULTS: Lung function assessment showed a typical obstructive pattern (n = 5) and air trapping (n = 7). Typical bronchiolar infiltration by lymphocytes and plasma cells and accumulation of foamy macrophages in the intraluminal tissue were detected in open lung biopsy specimens (n = 2). Chest radiographs and high resolution computed tomographic scans revealed hyperinflation, diffuse nodules, bronchial thickening and dilatation, peripheral hypoattenuation, and bronchiolectasis. Radiological improvement, manifest as a reduction in nodular density and bronchial thickening, and persistence of other abnormalities such as air trapping were not accurately depicted by the classical Nakata or Akira classifications. The other "characteristic" features such as HLA-B54, IgG subclass deficiency, raised CD4/CD8 T lymphocyte ratio, cold haemagglutinaemia, raised IgA, IgG, and rheumatoid factor were not present. Treatment with erythromycin led to excellent responses in symptoms, lung function indices, and the radiological picture. A review of the non-Japanese cases in the literature reveals that this absence of typical "additional features" in DPB might also be applicable to non-Japanese patients. CONCLUSIONS: We report the only series of non-Japanese Mongoloid patients with well characterised DPB who had uncharacteristic investigation profiles. This experience should help other clinicians in the investigation and management of DPB in non-Japanese patients.

Adult↗
PubMed1998

Inhaled fluticasone reduces sputum inflammatory indices in severe bronchiectasis.

Although corticosteroid therapy might be clinically beneficial for bronchiectasis, very little is known of its effects on the inflammatory and infective markers in bronchiectasis. We have therefore performed a double-blind, placebo-controlled study to evaluate the effects of a 4-wk administration of inhaled fluticasone in bronchiectasis. Twenty-four patients (12 female; mean age 51 yr) were randomized into receiving either inhaled fluticasone (500 microgram twice daily) via the Accuhaler device (n = 12) or placebo. At each visit, spirometry, 24-h sputum volume, sputum leukocyte density, bacterial densities, and concentrations of interleukin (IL)-1beta, IL-8, tumor necrosis factor-alpha (TNF-alpha), and leukotriene B4 (LTB4) were determined. There was a significant (p < 0.05) decrease in sputum leukocyte density and IL-1beta, IL-8, and LTB4 after fluticasone treatment. The fluticasone group had one and the placebo group three episodes of exacerbation. There were no significant changes in spirometry (p > 0.05) or any reported adverse reactions in either group. The results of this study show that high-dose fluticasone is effective in reducing the sputum inflammatory indices in bronchiectasis. Large-scale and long-term studies are indicated to evaluate the effects of inhaled steroid therapy on the inflammatory components in bronchiectasis.

Administration, Inhalation↗
PubMed1998

Risk factors for pulmonary tuberculosis in bone marrow transplant recipients.

Little is known about the profile of infection with Mycobacterium tuberculosis in bone marrow transplant (BMT) recipients. Of five BMT series with a total of more than 5,000 patients, only 10 cases of M. tuberculosis infection were described, with an overall incidence of 0.19%. We have conducted a prospective evaluation of 183 consecutive BMT recipients, and 10 patients were found to develop pulmonary tuberculosis post-BMT, yielding an incidence of 5.5%. We described the clinical features of these 10 patients, and analyzed the risk factors for development of tuberculosis using age- and sex-matched case control subjects who did not develop the disease. The median age of the 10 patients who developed tuberculosis was 29 yr (range, 17 to 40 yr). The median time for onset of symptoms was 150 d (range, 23 to 550 d), mainly presenting with fever and cough, with infiltrates on chest radiograph. Respiratory tract specimens, mostly sputum, yielded positive smears for acid-fast bacilli in three and positive M. tuberculosis culture in eight, whereas lung tissue histology was the first diagnostic test in two patients. Treatment with standard antituberculosis drugs for a longer duration was highly effective, with no excessive side effects. Risk factors identified for development of tuberculosis included allogeneic BMT (p < 0.05, relative risk [RR] = 23.7), total body irradiation (p < 0. 05, RR = 4.9), and chronic graft-versus-host disease (GVHD) (p < 0. 05, RR = 3.6). It is postulated that chronic GVHD predisposed to development of tuberculosis mainly via disruption of host reconstitution of immune defenses against M. tuberculosis.

Adolescent↗
PubMed1998

High seroprevalence of Helicobacter pylori in active bronchiectasis.

Helicobacter pylori causes chronic inflammation of the gastric mucosa and has been identified in tracheobronchial secretions. Serum IgG against H. pylori was therefore measured prospectively in consecutive subjects with bronchiectasis (n = 100; mean age +/- SD 55.1 +/- 16.7 yr), active pulmonary tuberculosis (n = 87; age, 57.3 +/- 19.1 yr), and healthy volunteers (n = 94; age, 54.6 +/- 7.6 yr). Seropositivity was found in 76.0% of bronchiectatic subjects, which was significantly higher than that of the control (54.3%, p = 0.001) and tuberculous (52.9%, p = 0.0001) groups. Multiple logistic regression, adjusted for age, sex, occupational social class, and number of persons living in the household, showed that H. pylori IgG levels of the bronchiectatic group were still significantly higher than that of the control (p = 0.0014) and tuberculous (p = 0.0154) groups. Multiple regression analysis revealed associations between H. pylori serology and sputum volume (p = 0.03) and age (p = 0.001) in the bronchiectatic patients, but not lung function indices or causes of bronchiectasis. The H. pylori seroprevalence in bronchiectasis was significantly (p = 0.0002) higher in patients who produced more (83.1%) than those who produced less than 5 ml sputum/24 h (58.6%). This is the first report of a high H. pylori seroprevalence in bronchiectasis which appears to be specific. Further studies are indicated to evaluate the possible pathogenic role of H. pylori in bronchiectasis.

Age Factors↗
PubMed1998

The effect of Pseudomonas aeruginosa infection on clinical parameters in steady-state bronchiectasis.

STUDY OBJECTIVE: To investigate the effect of Pseudomonas aeruginosa infection on clinical parameters in Chinese patients with noncystic fibrosis and steady-state bronchiectasis. DESIGN: Prospective, cross-sectional clinicomicrobiological study with informed consent. SETTING: Consecutive outpatient recruitment from a specialist bronchiectasis respiratory clinic. PATIENTS: Outpatients (n = 100; 62 women; 55.1+/-16.7 years old; FEV1/FVC 1.4+/-0.7/2.1+/-0.9 L), who had stable respiratory symptoms for more than 3 weeks. MEASUREMENTS AND RESULTS: Respiratory pathogens isolated from the sputum were: Pseudomonas aeruginosa (33), Haemophilus influenzae (10), Moraxella catarrhalis (2), other Gram-negative bacilli (5), Streptococcus pneumoniae (6), Staphylococcus aureus (5), mycobacteria (3), and yeast (1). Clinical parameters in patients with positive isolation of P aeruginosa were compared with those without the organism in the sputum culture (non-P aeruginosa). In the P aeruginosa group, the FEV1/FVC ratio and sputum volume were lower (p < 0.005) and higher (p < 0.0001), respectively, than those of the non-P aeruginosa group. The FEV1/FVC ratio (< 60%) and sputum volume (grading > 5) were independently associated with a positive sputum isolation of P aeruginosa with odds ratios of 3.1 (confidence interval [CI] 1.2 to 8.4; p < 0.01) and 4.7 (CI 1.6 to 13.3; p < 0.001), respectively. CONCLUSIONS: P aeruginosa is the predominant respiratory pathogen isolated in the sputum of Chinese patients with steady-state bronchiectasis, and its isolation is associated with high sputum output (> or = 75th quartile) and moderately severe airflow obstruction (FEV1/FVC < 60%).

Adult↗
PubMed1998

Bronchodilator responses to salbutamol using diskhaler versus metered-dose inhaler.

In adults inhaling salbutamol via metered-dose inhalers (MDls) 200 microg doses are recommended, but with diskhalers the manufacturer advocates 400 rather than 200 microg doses. To assess this advice, a partially double-blind, placebo-controlled salbutamol dose response, crossover study (also incorporating MDI doses) was conducted in 12 mild/moderate asthmatics. After active treatment, mean peak expiratory flow rate (PEFR) increments yielded no clinically or statistically significant differences; compared to placebo, respective median differences in PEFR increments (95% Cls) were 10 (-10, 50), 20 (0, 50), and 15 (0, 30) following 400 and 200 microg via diskhalers and 200 microg via MDls. Diskhalers are a suitable alternative for patients with poor MDI technique, but the use of 400 rather than 200 microg salbutamol doses is not supported by evidence.

Adrenergic beta-Agonists↗
PubMed1998

Obstructive sleep apnea syndrome: an experience in Chinese adults in Hong Kong.

OBJECTIVE: Epidemiologic studies in Caucasian populations suggested that symptomatic obstructive sleep apnea (OSA) occurred at a prevalence of 1-10%. The condition has been increasingly recognised among the Chinese in Hong Kong. We therefore, summarize our experience with OSA at the Department of Medicine, The University of Hong Kong at Queen Mary Hospital from 1985-1996. METHODS: All clinic records concerning demographic data, anthropometric data, clinical features, polysomnographic findings and treatment were reviewed. RESULTS: One hundred and twenty-two patients were diagnosed to have OSA. Demographic and clinical features were similar to Caucasian data with a male predominance of 84%, a mean age of about 50 years, and obesity as a risk factor at a mean body mass index of 30.4, which was higher than that of the average local population, although lower than that of OSA patients in Caucasian series. About 27% of the patients have a body mass index (BMI) similar to or below the population average. Nearly all were habitual snorers, and the majority had excessive daytime sleepiness. On polysomnography, the mean apnea-hypopnea index was 38. Common associated medical conditions were hypertension (34%), diabetes mellitus (10%), ischemic heart disease (9%), hyperlipidemia (6%). Most patients were managed successfully with nasal continuous positive airway pressure. Treatment with oral appliances for milder cases is being explored. CONCLUSIONS: OSA has been increasingly recognised among Chinese adults in Hong Kong in the past decade. Demographic features were similar to Caucasian data. The majority of patients were overweight, although 27% were not, and further investigation on the contribution of faciomaxillary morphology to OSA in this group is warranted.

Aged↗