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Biomedical subjects

I Gregg

Publications and source records attributed to I Gregg.

14 recordsLinked to original sources

Can measurement of peak expiratory flow enhance compliance in chronic asthma?

Almost all patients with chronic asthma will derive benefit from self-measurement of PEF. Unquestionably, this is of value for educating patients about their disease and treatment, leading in turn to improved compliance. It will be several years before it becomes clear what proportion of patients are willing to manage their asthma themselves and are sufficiently competent in the interpretation of their measurement of PEF to do so safely. It remains to be seen what effect greater use of PEF measurement by patients will have upon present levels of morbidity and mortality from asthma.

Asthma

A longitudinal study of baseline FEV1 and bronchial responsiveness in patients with asthma.

The effect of initial airway calibre on the response to bronchial provocation is unclear. Theoretically, geometric relationships within the airways might influence the measurement of responsiveness, particularly since a given change in calibre will produce a disproportionately greater reduction in flow in airways which are already narrowed. We have examined the relationship between serial measurements of prechallenge forced expiratory volume in one second (FEV1) and responsiveness to methacholine (PD20) in 8 children and 12 adults with asthma. Measurements were made every 2-3 wks for 12-18 months and all patients kept a daily record of symptoms and twice daily measurements of peak expiratory flow (PEF). Spearman's rank correlation coefficient (rho) for the relationship PD20 versus pre-challenge FEV1 was derived for each patient and varied widely within the group (range -0.22 to 0.73, mean 0.31); the strength of this correlation was not related to a patient's mean FEV1 % predicted, but was related to the degree to which PD20 and pre-challenge FEV1 themselves reflected concurrent asthma severity (mean morning PEF and mean symptom scores for the three days around each test). This suggests that the observed relationship between pre-challenge FEV1 and PD20 may be due less to the influence of airway geometric factors, which might be expected to be present in all patients, but rather that pre-challenge FEV1 is reflecting the severity of the underlying disease. Larger studies will be needed to test this hypothesis further.

Adolescent

Does non-specific bronchial responsiveness indicate the severity of asthma?

It is difficult to analyse the relationship between bronchial responsiveness and the severity of asthma since each alone is difficult to assess. Asthma is a heterogeneous condition with many patterns of expression, and clinical methods used to assess its severity have their limitations. Problems also arise in interpreting the results of bronchial provocation tests and methodological differences make comparisons between studies difficult. The findings of both cross-sectional and longitudinal studies have shown a general relationship between the degree of responsiveness and the severity of asthma, but within subjects the relationship is weaker. A greater understanding must await increased knowledge of the mechanisms underlying asthma and the contribution which hyperresponsiveness makes to each of these.

Asthma

Respiratory viral infection and wheezy bronchitis in childhood.

The role of respiratory viral infection in wheezy bronchitis was studied in 163 children, aged 0-12 years, in a London general practice. Virological investigations were also performed when these same children had acute upper respiratory illness without wheeze. A virus was isolated in 146 (26.4%) of 554 episodes of wheezy bronchitis, rhinoviruses accounting for almost half of the isolations. The relative frequency with which individual viruses were isolated in wheezy bronchitis was similar to that in acute upper respiratory illness in 180 other children who had never had wheezy bronchitis. The large number of isolations of rhinoviruses in wheezy bronchitis is probably due to their numerous serotypes and the absence of cross-immunity between them. Our findings have confirmed that infection by respiratory viruses can provoke wheezy bronchitis in certain children, in whom host factors are an important predeterminant. In children with a previous history of wheezy bronchitis infection by rhinoviruses was associated significantly more often with such an episode than with upper respiratory illness. The maturation of protective mechanisms, including the acquisition of specific immunity to a progressively larger number of viruses, could explain the fall in the age-incidence of wheezy bronchitis.

Age Factors

A long-term study of labetalol in general practice.

1 Forty-one patients with mild to moderate hypertension have been treated with labetalol for up to 5 years. 2 Mean BP before treatment was 180/107 mm Hg, after 2--3 yr treatment was 136/81 mmHg and after 5 yr was 136/74 mmHg. 3 One patient developed a licheniform rash and two patients have died of myocardial infarction. No other side-effects, not already observed in a previously reported double-blind trial, have emerged.

Adult

Experience of the use of beclomethasone dipropionate aerosol in general practice.

1. The findings of an open trial of beclomethasone dipropionate aerosol (BDA), carried out in 1972 in the author's general practice, are discussed in the light of subsequent, more extensive experience of its use of BDA. 2. An important reason why BDA may be unsuccessful in controlling asthma, and may give rise to various problems, is that patients are often given an inadequate explanation of the purpose and proper use of this treatment.

Adrenal Cortex Hormones

The difficult asthmatic.

The most common reason why asthma presents difficulties in management is the failure to treat it with drugs which are appropriate and taken in adequate dosage. An understanding of the pathophysiology and aetiology of asthma is essential if full advantage is to be taken of the wide range of drugs now available for treating it. Airflow obstruction due to bronchial muscle constriction is usually readily reversible by bronchodilators, whereas that due to the inflammatory component of asthma is refractory to the latter and can only be reversed by steroids. Refractory airflow obstruction is liable to be confused with irreversible obstruction which occurs in those patients whose asthma is complicated by chronic obstructive bronchitis or other lung disease. The choice between symptomatic, preventive and suppressive forms of treatment should be made only after a careful assessment has been carried out with objective measurement of airflow obstruction. The Wright peak flow meter is unsurpassed for this purpose. By its means it should be possible to estimate how much of a patient's airflow obstruction is readily reversible, how much is refractory and how much is irreversible. In general, the aim of treatment is to relieve airflow obstruction rather than to counteract supposed aetiological factors. Both doctor and patient must understand the purpose, limitations and possible dangers of any drug which is prescribed. Steroids are the only form of treatment which is effective in persistent refractory asthma. Prejudice against steroids has resulted in many patients being deprived of their benefit, but this situation may change with the recent introduction of steroid aerosols.

Adrenal Cortex Hormones

Double-blind trial of labetalol.

1 A new anti-hypertensive agent (labetalol) with alpha- and beta-adrenoreceptor-blocking properties has been assessed in 30 patients in a general practice. 2 Significant reduction in blood pressure and pulse rate occurred at a dose of 400 mg/d. A further significant reduction in blood pressure but not of pulse rate occurred at a dose of 800 mg/d. 3 After 4 weeks' treatment on the higher dose the mean fall in systolic and diastolic pressures compared with the pre-trial pressures was 36 and 24 mmHg, respectively. Side-effects were generally mild.

Adult

Respiratory viral infection in childhood. A survey in general practice, Roehampton 1967-1972.

The role of viruses and M. pneumoniae in episodes of acute respiratory illness in childhood has been studied in a London general practice. The total isolation rate was 31-7 per cent, but the rate varied from 32-6 per cent in upper respiratory infections to 64-0 per cent in pneumonia. The clinical features associated with infection were influenced not only by the type of agent but also by age and other host factors in infected children. Rhinoviruses were more commonly isolated than any other agent and were frequently associated with wheezy bronchitis.

Adenoviridae