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Biomedical subjects

W G Allan

Publications and source records attributed to W G Allan.

At least 19 recordsLinked to original sources
PubMed1985

Silicosis in jade workers.

The recent finding of cases of silicosis among jade workers in Hong Kong points to this disease being an occupational hazard. The source was found to be the silica flour that was added in a polishing process. Five cases are described together with the results of environmental investigation in a workplace. In three cases the disease was of early onset, rapidly progressive, and presented the features of galloping silicosis noted in other occupational exposures to silica flour. One patient had massive fibrosis and severe glomerulonephropathy, an association that has also been previously noted. One case showed evidence of active tubercular infection in addition to silicosis and two had healed lesions. Silica concentrations in the workplace during the suepect process were well above accepted threshold limit values.

Adult↗
PubMed1983

Amikacin in the treatment of pulmonary tuberculosis.

Sensitivity tests on strains from 11 patients with pulmonary tuberculosis, previously treated with kanamycin and/or capreomycin, showed incomplete cross-resistance between amikacin and capreomycin but complete cross-resistance between amikacin and kanamycin. Treatment with amikacin of 4 patients with multiply resistant strains resulted in no response as assessed by sputum smears and cultures, but resistance emerged to amikacin, kanamycin and capreomycin. Amikacin has no role in the treatment of tuberculosis as it cannot be given as an alternative to kanamycin, has no advantages over it and is more expensive.

Adult↗
PubMed1981

Serum uric acid concentrations and arthralgia among patients treated with pyrazinamide-containing regimens in Hong Kong and Singapore.

The serum uric acid concentrations of patients being treated in Hong Kong and Singapore with a daily regimen consisting of streptomycin, isoniazid, rifampicin and pyrazinamide or a control regimen of daily streptomycin, p-amino-salicylic acid (PAS) and isoniazid were determined by the phosphotungstate method. Arthralgia and elevated serum uric acid levels were encountered only during the period that patients were being treated with pyrazinamide. Although daily treatment with pyrazinamide increased serum uric acid concentrations approximately 2.5-fold, the concentrations of the 6 patients who developed arthralgia were closely similar to those of matched controls without arthralgia. This fails to confirm a previous suggestion that patients with arthralgia might have higher values. Rifampicin appeared not to influence the hyperuricaemic effect of pyrazinamide.

Humans↗
PubMed1981

A survey of deaths in Hong Kong attributed to tuberculosis.

Records obtained for 578 (96%) of the 602 patients certified as having died from tuberculosis in Hong Kong during a 1-year period were reviewed by an expert independent assessor in London, In his opinion 14 (2% of the 578) had never had tuberculosis, and in 28 (5%) it was not possible to decide whether or not the patient had ever had tuberculosis. Tuberculosis had been no more than a contributory factor in causing death in 44 (8%), in 29 (5%) it was irrelevant, and in 33 (6%) it was not possible to determine what role it had played. The remaining 430 (74%) patients were considered actually to have died from tuberculosis, 307 from active disease and 123 from the late effects of inactive disease. If all 578 patients had died from tuberculosis this would represent a death rate for the survey year of 13.1 per 100 000 of the population. The rate falls to 9.7 per 100 000 if based on the 430 patients considered by the assessor to have died from tuberculosis, a reduction of 26%. Since the annual death rate from active disease (6.9 per 100 000 in this survey) is a better index of the current efficiency of an antituberculosis programme than the total death rate, it is suggested that efforts should be made to obtain and publish separate annual rates for deaths from active and from inactive tuberculosis. An analysis of potentially avoidable delays and failures in diagnosis showed that these were mainly due to the patient's delay in seeking or accepting advice, or inadequate investigation, particularly failure to examine the sputum, by the unofficial (non-governmental) medical services. The majority of failures in management were attributable in whole or in part to the patient.

Adolescent↗
PubMed1980

Antibody response following prolonged hyposensitization with Dermatophagoides pteronyssinus extract.

An antigen-binding radioimmunoassay was used to measure IgG, IgA and IgE antibody (ab) to Dermatophagoides pteronyssinus in sera from patients who had been hyposensitized with either aqueous D. pteronyssinus extract or placebo. An allergen, F4P1, was obtained from D. pteronyssinus culture and 125I-labelled for use in the assay. The radioallergosorbent test was also used to measure IgE ab to D. pteronyssinus and IgE ab to Dermatophagoides farinae. The radioimmunoassay results showed a selective rise in IgG ab in sera from D. pteronyssinus-treated (DP) patients. An increase of greater than twofold in IgG ab in post-treatment sera was found in 27 of 29 DP patients compared to 1 of 29 placebo-treated ('placebo') patients (p less than 0.001). The mean rise in IgG ab in DP patients was sixfold, and the maximum rise was 50-fold. There was little change in the levels of IgA ab or IgE ab in either DP or 'placebo' patients during treatment. The DP patients showed significant clinical improvement compared with the 'placebo' patients (p less than 0.01). However, no correlation was found between post-treatment IgG ab and post-treatment symptom scores, or between the changes in IgG ab and the changes in symptom scores during treatment. The time course of the antigen-binding assay was investigated using very low concentrations of F4P1. The results showed that antigen-binding was slow, even in the presence of an excess of IgG ab. The role of IgG ab in hyposensitization is discussed.

Animals↗
PubMed1979

The symptoms of newly diagnosed pulmonary tuberculosis and patients' attitudes to the disease and to its treatment in Hong Kong.

A questionnaire was applied by Government Health Visitors in Hong Kong to 201 consecutive patients with smear-positive, and 199 with smear-negative pulmonary tuberculosis who were attending one of the 7 full-time Government chest clinics for the first time on account of their current illness. Information was obtained about the symptoms of the disease and its diagnosis and management outside the Government service, and about patients' knowledge and attitudes towards the Government service. Among the 343 patients who sought treatment because of respiratory symptoms, the first symptom for the great majority (81 %) was cough, 15 % having sputum and 27 % haemoptysis as well. However, treatment was sought by only 15 % because of cough alone, compared with 40 % because of haemoptysis. Most patients (76 %) attended their first source of treatment or investigation within a month of the onset of symptoms, but some allowed long delays, and only 35 % attended a Government chest clinic within a month (whether this was the first source of treatment or not). The first source attended was a private practitioner for 53 % of the patients, another private medical establishment for 4 %, a Government chest clinic for only 11 % and another Government medical establishment for 17 %, 9 % went first to a herbalist and 5 % went to a drug store or treated themselves. The delays between the patients' first attendance at a source of treatment and their first attendance at a Government clinic were important, because outside the Government chest clinics only 49 % were investigated by chest radiograph and only 7 % by sputum bacteriology. Only 33 % were even suspected of having pulmonary tuberculosis, and many were correspondingly inadequately treated. The patients were, in general, ill informed about the Government chest clinic service; 52 % did not know, before their current illness, of the existence of the service, only 9 % knew that it was free, and only 12 % that it specialised in the management of tuberculosis. This study thus revealed a need to educate the public about the symptoms of tuberculosis, and about the possibility of their being investigated and treated, free, in a Government chest clinic.

Adolescent↗
PubMed1979

Double blind controlled comparison of aspirin, allopurinol and placebo in the management of arthralgia during pyrazinamide administration.

Chinese patients with arthralgia during treatment with an antituberculosis regimen containing pyrazinamide were allocated at random to 3 anti-arthralgia treatment series in a controlled double-blind study. One series (18 patients) received soluble aspirin 2.4 g daily, the second (23 patients) allopurinol 200 mg daily, and the third (19 patients) placebo only, for 8 weeks. The response was assessed both by independent assessors and by the patients themselves using a diary card. The serum uric acid concentration was measured before and during anti-arthralgia treatment. The joints most commonly affected were the shoulders, the knees and the fingers, and symptoms and signs were in general neither severe nor protracted. For most of the patients in all 3 series the joint symptoms and signs improved during the 8 weeks, but a higher proportion of patients in the aspirin and placebo series than in the allopurinol series experienced improvement, this being most rapid in the aspirin series. Only in the aspirin series was the mean serum uric acid concentration lower during treatment than before it, and this effect was related to the dose in mg per kg. It is concluded that the arthralgia was often self-limiting, that aspirin had a small beneficial effect, that allopurinol, in the dosage studied, may have had a slightly deleterious effect, but that it would be worth studying larger dosages of allopurinol because the dosage studied did not affect the serum uric acid concentration.

Adolescent↗
PubMed1977

Study of prolonged hyposensitization with D. pteronyssinus extract in allergic rhinitis.

Sixty-six Chinese patients with rhinitis, with or without asthma, were randomly allocated to a course of injections either with E. pteronyssi-us extract or placebo. The course consisted of 18--22 weekly injections, followed by monthly maintenance injections with the highest concentration for 1 year. Progress was evaluated by a patient's daily diary and monthly assessments by the physician, by comparisons of skin and nasal challenge tests and by the specific serum IgE concentration, before treatment, at the end of the weekly course, and once during the maintenance course. No improvement was detected at the end of the weekly course, but during maintenance there was a consistent benefit to the patients receiving the D. pteronyssinus extract both in the diary and the physician's assessment, especially the former. There was no consistent change in the skin or nasal challenge tests and there was a trivial fall in the serum IgE levels in the patients on the extract. Adverse reactions were much more common in the patients on the extract, but most were trivial. The different methods of assessment used and the role of hyposensitization with D. pteronyssinus are discussed.

Administration, Intranasal↗
PubMed1975

A study to assess the intradermal, triangular needle and bifurcated needle techniques in the administration of BCG to newborns.

BCG at birth was administered to 3,297 new born babies in Hong Kong using the intradermal, simple triangular and bifurcated needle techniques. Tuberculin testing at 3 months showed similar mean reactions for the intradermal and simple triangular needle methods, namely 9-74 mm and 9-87 mm with 9-94 mm for the triangular needle method when the BCG strength was doubled. Using the bifurcated needle the mean reactions were significantly lower; 8-69 mm, 9-01 mm with double strength BCG and 8-92 mm with puncture through a skin drop. It is concluded that the bifurcated needle is not a satisfactory method of administering BCG to newborns even if the concentration of BCG is increased. In circumstances such as in small maternity units, where the intradermal technique is not warranted, it is recommended that the simple triangular method should be used.

BCG Vaccine↗
PubMed1972

Adverse reactions to daily and intermittent rifampicin regimens for pulmonary tuberculosis in Hong Kong.

This paper reports the nature, incidence, and severity of adverse reactions to regimens of rifampicin and ethambutol given once weekly, twice weekly, or daily and to a standard reserve regimen in a total of 330 Chinese failure patients who completed at least six months' chemotherapy in a therapeutic comparison in Hong Kong.The adverse reactions which occurred on the regimens of intermittent rifampicin were termed cutaneous, abdominal, "flu", and respiratory; in addition, purpura and abnormal liver function tests were encountered. There was an association of adverse reactions with the interval between doses and with the dose size of rifampicin, the highest incidence occurring with once-weekly rifampicin in high dosage. A procedure was developed for managing adverse reactions to intermittent rifampicin. Of 202 patients treated with intermittent rifampicin 60 developed adverse reactions, but in only 7 (3%) was it necessary to terminate the drug, though a further 10 (5%) were changed to daily rifampicin. On daily rifampicin, generalized hypersensitivity, cutaneous reactions, (one with purpura), and impaired liver function were encountered. Adverse reactions on the standard ethionamide, pyrazinamide, and cycloserine regimen were frequent and some were serious.

Alanine Transaminase↗