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Biomedical subjects

W K Lam

Publications and source records attributed to W K Lam.

At least 145 records · Page 8Linked to original sources

Twice daily administration of beclomethasone dipropionate dry-powder in the management of chronic asthma.

In a double-blind cross-over study beclomethasone dipropionate inhaled as a dry-powder in a dose of 400 micrograms twice daily was compared with a conventional aerosol in a dose of 100 micrograms four times daily in 16 outpatients with chronic asthma. Each of the 2 treatments lasted for 4 weeks. There was no significant difference with respect to daily peak expiratory flow rates, symptom scores, bronchodilator usages and other lung function measurements between the 2 treatments. Tetracosactrin tests were within normal limits and no clinical oral candidiasis was observed throughout the study. In conclusion, beclomethasone dipropionate dry-power given twice daily was effective for the control of asthma and could be recommended for patients with poor drug compliance.

Administration, Inhalation↗

Evidence that respiratory tract is major reservoir for Epstein-Barr virus.

Exfoliated cells harvested from bronchial washings of 53 patients with suspected bronchogenic carcinoma were tested by means of DNA dot hybridisation using the cloned large internal repeat (IR) sequence of Epstein-Barr virus (EBV) genome as a probe. 25 of these patients gave positive results. Since the patients had diseases that were not related to the virus, this finding suggests that the lower respiratory tract is a major reservoir for EBV. Attempts at cellular localisation of the virus revealed only an occasional cell which harboured the viral genome or expressed viral capsid antigens. These cells could not account for the quantity of the viral DNA detected in bronchial washings. Moreover, patients had similar profiles of serum EBV antibodies whether they were positive or negative for EBV DNA by dot hybridisation. These findings are compatible with a state of viral latency in which cells harbour a low copy number of the viral genome. Viral expression rarely occurs in these cells, which seem to elicit a minimum host immune response. If it is assumed that each latently infected cell harbours a maximum of approximately 30 EBV genomes (which is the lower limit of detection by the in-situ hybridisation method used in this study), the findings suggest that a considerable proportion of the exfoliative cells from the lower respiratory tract, of the order of 0.1-16%, harbour latent EBV.

Adult↗

Cyclic combination chemotherapy in advanced adenocarcinoma of the lung: comparison of two FAM schedules.

Forty patients with advanced adenocarcinoma of the lung were treated by two FAM chemotherapy schedules. Group A (20 patients) received Futraful, adriamycin, and mitomycin C, and group B (20 patients) received 5-fluorouracil, adriamycin, and mitomycin C. The response/stabilization rate was greater for group B (4 partial responses + 4 cases of stable disease) than for group A (no responders + 5 cases of stable disease), and the median survival was longer for group B (32 weeks) than for group A (22 weeks), although the differences did not reach statistical significance in either case (P greater than 0.05). Myelotoxicity was mild in both schedules. Further studies of the two FAM schemes at an escalated dose would be worthwhile.

Adenocarcinoma↗

Pulmonary scar cancer. A pathologic reappraisal.

A total of 49 consecutive specimens of lung cancer were collected prospectively at surgical resection or autopsy from 40 men and nine women, aged 40-74 years. Of the 49 tumors, the gross appearance of 22 fitted the description of a scar cancer, i.e., a tumor with pleural puckering and central pigmentation. Nineteen of the "scar cancers" were peripheral (17 adenocarcinomas and two squamous cell carcinomas); three were central (one squamous cell carcinoma and two adenocarcinomas). In the 19 peripheral "scar cancers," elastic stains demonstrated the presence of collapsed, unfibrosed lung tissue at the center with traction of the overlying pleura toward it. Elsewhere in the tumor, the elastic framework was either destroyed or expanded by tumor filling the alveolar spaces. None of the "scar cancers" had a significant desmoplastic reaction that might otherwise explain the scarred appearance. It appeared that local atelectasis was solely responsible for the pleural puckering and central pigmentation. On the other hand, atelectatic lung tissue was not seen in the 27 cancers that did not have the appearance of a scar cancer. Tuberculosis was found in 10 of the 49 lung specimens. In only one specimen was the tuberculous lesion anatomically associated with the tumor. There was no evidence of pulmonary infarct in any of the specimens. The term "scar cancer" was considered inappropriate as there was no preformed fibrous tissue. The scarred appearance was thought to be the result of localized pulmonary atelectasis owing to small airways obstruction by tumor. Association with tuberculosis was considered incidental.

Adenocarcinoma↗

Selective 5-HT2 receptor blockade in exercise-induced asthma.

Seven young extrinsic asthmatics participated in an open, pilot study to determine the protective effect of a selective 5-hydroxytryptamine (5-HT) blocking agent, ketanserin, on exercise induced asthma. Ketanserin in a dose of 10 mg given intravenously 20 min before exercise altered the basal bronchomotor tone in only 1 of 6 subjects and offered partial protection against exercise-induced bronchoconstriction in 1 of 5 asthmatics with no overall effect in the group. All patients experienced sleepiness after administration of ketanserin and one had bradycardia with hypotension. The ineffectiveness of ketanserin suggests indirectly that serotonin has a limited role in the pathogenesis of exercise-induced asthma.

Adolescent↗

Occupational asthma due to formaldehyde.

Bronchial provocation studies on 15 workers occupationally exposed to formaldehyde are described. The results show that formaldehyde exposure can cause asthmatic reactions, and suggest that these are sometimes due to hypersensitivity and sometimes to a direct irritant effect. Three workers had classical occupational asthma caused by formaldehyde fumes, which was likely to be due to hypersensitivity, with late asthmatic reactions following formaldehyde exposure. Six workers developed immediate asthmatic reactions, which were likely to be due to a direct irritant effect as the reactions were shorter in duration than those seen after soluble allergen exposure and were closely related to histamine reactivity. The breathing zone concentrations of formaldehyde required to elicit these irritant reactions (mean 4.8 mg/m3) were higher than those encountered in buildings recently insulated with urea formaldehyde foam, but within levels sometimes found in industry.

Adult↗

A case of invasive penicilliosis in Hong Kong with immunologic evaluation.

A 53-yr-old Chinese sailor developed prolonged pyrexia with unresolved lobar pneumonia, cervical lymphadenopathy, generalized subcutaneous abscesses, and pericardial effusion. Penicillium marneffei was isolated from pericardial fluid and subcutaneous pus and was demonstrated on histologic sections of lymph nodes and lung tissue. The penicilliosis was treated successfully with amphotericin B, ketoconazole, and 5-fluorocytosine. Subsequently, he also developed other T-lymphocyte-related opportunistic infections such as disseminated cutaneous herpes zoster and chronic osteomyelitis of sternum caused by Salmonella typhimurium. He was also a chronic carrier of cytomegalovirus. Further investigations showed that he had persistent depression of T-lymphocyte function and enhancement of B-lymphocyte activity, the cause of which was undetermined.

Abscess↗

Respiratory problems in myasthenia gravis.

We evaluated our experience involving 27 patients with myasthenia gravis with particular reference to the various respiratory problems encountered. These included restriction of ventilation, respiratory tract infections, aspiration due to bulbar weakness, respiratory failure requiring mechanical ventilation, and post-thymectomy pulmonary complications.

Acute Disease↗

First report of septicaemic melioidosis in Hong Kong.

Septicaemia due to Pseudomonas pseudomallei was found in five patients; it complicated pneumonia in three. Four patients were old and had diabetes mellitus; the fifth patient, though young, was immunocompromised by steroid therapy. The clinical features were indistinguishable from those of other Gram-negative septicaemia. Four of the patients died. This was the first report of septicaemic melioidosis in Hong Kong where the disease might be endemic. Soil sampling and serological survey gave further supporting evidence. Early treatment using a bactericidal anti-Pseudomonal cephalosporin, such as ceftazidime, was suggested for this life-threatening infection.

Adult↗

Blue bodies in cytology specimens in a case of pulmonary talcosis.

Unusual extracellular birefringent laminated ovoid structures are seen in bronchial brushing, aspiration, and washing specimens in a 28-year-old woman who had histologic evidence of pulmonary talcosis. Energy dispersive x-ray analysis and microchemical studies have identified them to be calcium carbonate. These structures are known as pulmonary blue bodies and are seen mainly in histologic paraffin sections. Their occurrence in cytologic preparations and association with talcosis have not been reported.

Adult↗

Clinical features of bronchogenic carcinoma in Hong Kong. Review of 480 patients.

A retrospective study was made of 480 Chinese patients with proven bronchogenic carcinoma, the top cancer in Hong Kong. The male-to-female sex ratio was low (1.9:1) and the female mortality rate ranked amongst the world's highest. The four major histologic types accounted for 87% of the cases: 39% epidermoid, 12% small cell anaplastic, 29% adenocarcinoma, and 7% large cell anaplastic. History of smoking was associated with epidermoid and small cell anaplastic carcinoma only. The commonest symptoms were anorexia and malaise (67%) and cough (51%). Overall our patients presented late and only 30 (6%) had curative surgery. The relatively rare occurrence of deep vein thrombosis (0.7%) is in keeping with the known low incidence of venous thrombosis in Chinese. Adenocarcinoma was a distinct group characterized by its preponderance in females (43%), lack of association with smoking habit (61% female cases being nonsmokers), high frequency of neurologic manifestation (21%) and clinical, roentgenographic, and bronchoscopic features of a predominantly centrally situated tumor. Possible etiologic factors for the high and still increasing incidence of adenocarcinoma are discussed.

Adenocarcinoma↗

Can hypertransfusion attenuate myelosuppression associated with combination chemotherapy in patients with inoperable bronchogenic carcinoma? A report of a randomised, controlled study.

Based on the concept of "stem-cell competition," hypertransfusion has been shown to attenuate the leucopenia associated with chemotherapy in children with leukemia. We conducted a randomized, controlled study of hypertransfusion in 25 patients with inoperable lung cancer who received combination chemotherapy consisting of methotrexate, adriamycin, cyclophosphamide, and CCNU (Lomustine) (MACC scheme). Twelve patients in the hypertransfusion group were given red cell transfusion to a hemoglobin value greater than or equal to 17 gm/dl prior to each chemotherapy cycle. The two groups of patients were comparable in age, cell type, extent of disease, performance status, and initial hemoglobin level and blood counts. The mean fall in granulocyte count was greater for control group (3.76 X 10(9)/liter) than for hypertransfusion group (3.27 X 10(9)/liter), and the mean fall in platelet count was greater for control group (53.84 X 10(9)/liter) than for hypertransfusion group (35.83 X 10(9)/liter), although the differences did not reach statistical significance (p greater than 0.05) partly because our MACC scheme was probably not sufficiently myelosuppressive to bring about a difference in the two groups. Granulocytopenia-associated infections were infrequent in both groups: two episodes in 37 cycles of chemotherapy in the hypertransfusion group and three episodes in 43 cycles in the control group. Hypertransfusion was simple and safe, and the encouraging trend towards less marked myelosuppression in our hypertransfused group would warrant further studies using more intensive and myelosuppressive combination chemotherapy regimens.

Adult↗

Response to oral corticosteroids in chronic airflow obstruction.

Sixteen Chinese patients with chronic fixed airflow obstruction (mean age 62.5 years; mean forced expiratory volume in 1 second (FEV1) of 0.85 litres, and mean ratio FEV1/forced vital capacity (FVC) of 0.45) entered a randomized double-blind crossover trial comparing prednisolone 40 mg orally daily for 2 weeks with placebo. Nine of the 16 patients (56%) had an increase in FEV1 of 15% or more after prednisolone. Compared with placebo, prednisolone significantly improved objective measurements (mean FEV1 by 21.4%, mean FVC by 11.9%, mean daily peak expiratory flow rate by 22.6%), subjective measurement (mean dyspnoea score by 16%) and exercise performance assessed by the distance walked in 12 minutes (12MD, by 5.5%). Objective improvements in FEV1 and PEFR were correlated with subjective upgrading of the dyspnoea score, but were not paralleled by an improvement in 12MD. Changes in FVC correlated with neither. FEV1 was thus the best index of objective measurement. The following characteristics were examined for reliability in predicting steroid responsiveness: variability of symptoms, wheezing score, prick skin test positivity, initial bronchodilator response, peripheral blood and sputum eosinophilia, and serum and sputum immunoglobulin E (IgE) level. None was found to be useful. A therapeutic trial of oral corticosteroid should be considered in patients with chronic fixed airflow obstruction on an individual basis.

Administration, Oral↗

Successful treatment of melioidosis caused by a multiresistant strain in an immunocompromised host with third generation cephalosporins.

A 32-yr-old woman with active systemic lupus erythematosus receiving prednisone and azathioprine developed lung abscesses of the right lower lobe caused by Pseudomonas pseudomallei, which was resistant concomitantly to chloramphenicol, co-trimoxazole, and tetracycline, but highly sensitive to a new cephalosporin, ceftazidime. Melioidosis was treated successfully with lobectomy and parenteral ceftazidime, which was given for 2 months without major side effects. Ceftazidime, being bactericidal, may be more promising for the eradication of P. pseudomallei, especially in immunocompromised hosts. This was also the first reported case of melioidosis in Hong Kong, where the disease might be endemic, as 4 more cases were found later.

Adult↗