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Biomedical subjects

J B Cookson

Publications and source records attributed to J B Cookson.

14 recordsLinked to original sources

Does a positive Heaf test reaction in Asian schoolchildren predict later breakdown of tuberculosis?

BACKGROUND: Some authorities advise giving prophylactic antituberculosis treatment to those with a grade 3 or 4 reaction to Heaf tests performed as part of the schools' BCG programme. This is not done in Leicestershire, which because of its large Asian population would require considerable resources to do so. A calculation of the "breakdown" rate, and thus the potential value of chemoprophylaxis, in these children would therefore be valuable. METHOD: Lists of names of Asian children who had a grade 3 or 4 Heaf test reaction in 1982 and 1983 were compared with lists of notifications for the five years 1983 to 1987. Those who were on both lists were considered to have tuberculosis that had "broken down." RESULTS: Of the 760 children with positive Heaf test reactions, only four were on the subsequent notification lists. The chest radiograph obtained because of the Heaf test result showed evidence of active tuberculosis in only three of these. Only one child had infection that "broke down" later. CONCLUSION: The benefit of chemoprophylaxis seems likely to be limited in these Asian children, most of whom had received BCG early in life.

Adolescent

Normal pulmonary function in Botswana.

Forced vital capacity, forced expiratory volume in one second and peak expiratory flow rate were measured in 125 adult Batswana who were without evidence of pulmonary disease. Regression co-efficients suitable for the calculation of normal values for these parameters are presented. Results are similar to those in other Negroid populations but lower than in Caucasian subjects.

Adult

Auditing a research ethics committee.

Research ethics committees approve research on human subjects performed locally. They have been criticised for failing to perform this function adequately. I have, therefore, examined the structure and process of the committee for Leicestershire and compared it with the guidelines for these committees produced by the Royal College of Physicians and the Department of Health. The structure and function of the committee are described and conform well with the recommendations of the Royal College of Physicians and the Department of Health. An annual report to the health authority has not previously been produced but the need for this is now accepted. The suggestion for a lay chairman or vice-chairman has, however, been rejected. The workload has steadily increased over the past 10 years, from 66 protocols a year to 302. During a recent 12-month period, 277 research submissions were received; 143 of them were agreed without amendment, 93 with minor amendments, and 41 were rejected or required further information before they could be reconsidered. Assessment of outcome is more difficult. In future, the committee may ask for annual reports from investigators on their research and on any ethical problems encountered. Ethics committees need to foster good ethical research and inform researchers of ethical issues. Most of the latter are highlighted on the Leicestershire application form but are supplemented by short guidelines on particular topics. The committee consumes time and money; it is not clear if it will be adequately funded under the new NHS structure.

England

A DNA primer/probe system for the rapid and sensitive detection of Mycobacterium tuberculosis-complex pathogens.

A 1.5 kb EcoRI-BamHI restriction fragment from Mycobacterium tuberculosis was found to hybridize specifically with genomic DNA from M. tuberculosis-complex organisms. Primers were designed from the terminal sequences of this fragment and used to amplify uniquely M. tuberculosis-group DNA in a polymerase chain reaction. It is suggested that a combination of these primers and probe will prove a useful tool for the early diagnosis of tuberculous infections.

Base Sequence

Prophylactic intranasal alpha 2 interferon and viral exacerbations of chronic respiratory disease.

BACKGROUND As respiratory virus infections often lead to exacerbations of chronic bronchitis and asthma an effective antiviral drug may be helpful in such patients. Alpha 2 interferon has been shown to give protection against rhinovirus infections in field studies. METHODS Patients with chronic respiratory disease exposed to close contacts with symptoms of upper respiratory tract infection were randomly allocated to receive nasal sprays of recombinant alpha 2 interferon (3 x 10(6) IU) or placebo twice daily for five days. Of the 123 patients recruited into the study, 69 took 117 courses of medication; 11 courses were excluded from analysis. RESULTS No important side effects were recorded and the incidence of possible adverse effects was similar in the two groups. Interferon treatment did not reduce the number or severity of symptomatic episodes; 11 of 48 patients given interferon and 16 of 58 given placebo developed lower respiratory symptoms. There were no differences in mean symptom scores (51 interferon and 52 placebo), number of symptomatic days (3.3 interferon and 5.0 placebo), peak flow values, number of general practitioner consultations, or use of antibiotics. CONCLUSION Alpha 2 interferon 3 x 10(6) IU taken twice daily for five days does not protect patients with chronic respiratory disease from exacerbations after they have been in contact with an upper respiratory tract infection.

Administration, Intranasal

A comparison of inhaled beclomethasone dipropionate and nedocromil sodium as additional therapy in asthma.

We have compared the effects of inhaled beclomethasone dipropionate (BDP) 400 micrograms day-1 with inhaled nedocromil sodium (NDS) 16 mg day-1 as additional therapy in adults with asthma not fully controlled by regular beta-2-agonist inhalers with, or without, oral theophyllines. Seventeen subjects were entered into a 2-week baseline phase, and subsequently in a double-blind crossover fashion into two 8-week phases of daily BDP or NDS. Subjects recorded daily peak expiratory flow rates, morning and evening (PEF am and pm), symptom scores and beta-2-agonist inhaler use. Thirteen subjects completed the study and the last 2 weeks of each phase were analysed. Compared to baseline, both BDP and NDS caused a significant improvement in PEF am (P less than 0.05), PEF pm (P less than 0.05) and the 'amplitude % mean' (P less than 0.001). Both drugs gave a highly significant improvement in all symptom scores. There was no significant difference between BDP and NDS for PEF am, PEF pm, amplitude % mean, cough and daytime asthma score. However, beta-2-agonist inhaler use and scores for nocturnal asthma and morning tightness were all significantly better in the BDP phase, and may have contributed to its better overall subjective performance. Thus, both NDS and BDP resulted in a significant improvement in asthma control in the subjects studied, and both drugs caused a similar improvement in PEF.

Administration, Inhalation

Prevalence of chronic bronchitis in Rhodesian Africans.

The prevalence of chronic bronchitis in the African population of a small township in Rhodesia was estimated using two questionnaires, both based on those of the British Medical Research Council. The first, a screening questionnaire, was put to 9768 subjects aged 5 years and above and the second, a more detailed questionnaire, to random selections of these grouped according to their replies. Repeat interviews were used to assess the accuracy of the questionnaires. The overall prevalence of chronic bronchitis was 1.12%. This is much lower than most other surveys elsewhere. There was little evidence of an increase in prevalence with age, and rates were not significantly different in the two sexes. The prevalence of complications and of other chest symptoms was correspondingly low. The proportion of bronchitics who smoked was not significantly higher than in the controls. Amounts smoked, however, were generally much lower than in other populations, and this, together with low levels of pollution, probably account for the prevalence findings.

Adolescent

Experience with a tuberculosis antigen test in Rhodesia.

Experience with a new serological method for the diagnosis of tuberculosis is reported in a predominantly black population. We have found that in only 69% of 167 patients was there agreement between serology and the presence or absence of tuberculosis. Both false positive and false negative results were common. Of 47 healthy controls, 80% were positive. These results are less satisfactory than previous studies but differences in the reading of the results seems an unlikely explanation. Differences in the populations studied may be an important factor.

Agglutination Tests

Normal values for ventilatory function in Rhodesian Africans.

Forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow were measured in 141 African men and 102 African women aged 20 and above. Prediction formulae relating each measurement to height and age were drawn up and are presented. Rhodesian Africans have lower values for these measurements than subjects in some Europen and North American series, but broadly similar values to those of Africans elsewhere.

Adult

Allergy and parasites: the measurement of total and specific IgE levels in urban and rural communities in Rhodesia.

Eighty adult asthmatics living in an African city had a significantly higher serum IgE level (799 u/ml) than the control group (350 u/ml). A high proportion (78.7%) of the asthmatics had demonstrable circulating mite-specific IgE antibodies. The rural population of a filariasis endemic region was investigated and although no allergic subjects were identified, the group had a significantly higher IgE level (1613 u/ml) than the asthmatics and also showed a relatively high incidence of grass pollen-specific IgE antibodies (35%). The discrepancy between clinical history and laboratory results supports the mast cell saturation hypothesis and suggests: (a) an explanation for the susceptibility to allergy of African and Asian immigrants to Great Britain, and (b) a practical approach for preventing allergic reactions in vivo.

Adolescent

Identification of allergen-specific IgE antibodies in the sera of African asthmatics.

Of eighty African asthmatics, sixty-three had significant levels of specific IgE against the house dust mite dermatophagoides pteronyssinus. By contrast, grass-specific IgE was found in six patients and mould-specific IgE in none. Sixty-three patients also had symptoms predominantly during the rainy season. Positive skin tests against D. pteronyssinus correlated well with the presence of mite-specific IgE, as did the size of these skin test weals with the amount of specific IgE. For grass pollen and moulds there was no such relationship. There was no correlation between a history of sensitivity to house dust and either skin tests or specific IgE against D. pteronyssinus. The results support previous findings that it is allergy to house dust mite and not to grass pollens or moulds which is important in producing the seasonal symptoms in our patients.

Adult

Seasonal asthma and the house-dust mite in tropical Africa.

The relationship between seasonal asthma and sensitivity to the house-dust mite has been investigated in a country with large seasonal variations in relative humidity. Of seventy-eight African asthmatics, 64.1% gave a history probably suggestive of sensitivity to house-dust, and 55.1% a history strongly suggestive of such sensitivity. On skin testing, 35.9% had strong reactions to the house-dust mite Dermatophagoides pteronyssinus, compared with 1.9% of fifty-one matched controls without symptoms of chest disease. Few had either a history or skin tests suggestive of pollen or mould sensitivity. Most of the asthmatics were worse during the hot, wet season when the humidity is highest. This is also the time when in-patient asthmatics are most numerous. D. pteronyssinus grows well in warm, damp conditions and it is suggested that sensitivity to this mite may play a significant role in the marked seasonal changes seen in our asthmatic patients.

Adolescent