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Calcium B-PAS
325
LETTER
The Human Pulmonary Circulation-Its Form and Function in Health and Disease. P.
HARRIS
and D.
HEATH,
1962, E. & S. Livingstone, Edinburgh and London, £3 lOs.
In this book a physician has collaborated with a pathologist to interpret present knowledge of pulmonary circulation in its many different facets-the structure of the infant lung and its behaviour; the physical properties of the blood vesselsand the measurement of pressure flow, blood volumes of various tissue compartments, and pharmacological behaviour of the blood vessel wall; the interrelation of haemodynamics and gaseous exchange. These are all clearly and fully treated. The authors' main interest in the discussion of disease is with pulmonary hypertension, particularly in congenital and rheumatic heart disease and for its importance in clinical management in relation to surgical treatment. As this is a field in which the authors have made an important original contribution, it is dealt with at greater length than the changes in other pulmonary disease. The authors regret that their references have not been exhaustive, but they give no indication of the principle on which they have made their selection, with the result that in several fields their omissions are such as suggest either that material which has already been dealt with in the literature is original or that their view of current theories is biased. Nevertheless this book will be warmly welcomed by all concerned with heart and lungs.
LETTER CALCIUM B-PAS We were interested to read the leading article in the number of December 1961 (p. 541) concerning Calcium benzoyl PAS but feel that it too strongly supports this drug. The excellent controlled trial by Lees & Allen* is indeed the most worthy assessment of this drug so far. The results, however, were reviewed at six months only and this does not seem to justify their statement that, 'In long-term therapy aimed at preventing relapse, it is therefore both justifiable and advantageous to give calcium B-PAS to patients who prefer it'. Although these regimes were carefully supervised in hospital, which is utterly different from PAS prescribed for home use, it is disturbing to see that 2 cases of drug resistance had developed in each group within 3 months. We consider that these results should be confirmed and that a far more dependable assessment could be made on the second anniversary of the commencement of treatment. Before that time, commendation of Lees & Allen's conclusions in the leading article of the journal of the British Tuberculosis Association, is premature. It is likely that the large majority of patients require only minimal help from anti-tuberculosis drugs and thus minor deficiencies in the taking of PAS will be masked. Unfortunately, we are not able to determine the few who require the most effective long-term therapy to produce recovery and prevent drug resistance. The four instances of drug resistance reported by Lees & Allen within three months on regimes of PAS and isoniazid perhaps add to the view that PAS in any form is indeed a 'second line' drug. Furthermore, investigations designed to determine whether unsupervised patients consume their PAS have all shown that from one third to one half of them do not. We have little doubt that streptomycin and isoniazid under supervision form the dual drug therapy of choice at present and that to depend upon PAS consumption is to deny the facts-with inevitable harm to a small minority of patients. Hammersmith Chest Clinic, London, W. 12.
* Lees, A.
W., Allen, G. W. (1961). Brit, J. Dis. Chest. 55, 185.
PETER STRADLING GRAHAM POOLE
LETTER
The Human Pulmonary Circulation-Its Form and Function in Health and Disease. P.
HARRIS
and D.
HEATH,
1962, E. & S. Livingstone, Edinburgh and London, £3 lOs.
In this book a physician has collaborated with a pathologist to interpret present knowledge of pulmonary circulation in its many different facets-the structure of the infant lung and its behaviour; the physical properties of the blood vesselsand the measurement of pressure flow, blood volumes of various tissue compartments, and pharmacological behaviour of the blood vessel wall; the interrelation of haemodynamics and gaseous exchange. These are all clearly and fully treated. The authors' main interest in the discussion of disease is with pulmonary hypertension, particularly in congenital and rheumatic heart disease and for its importance in clinical management in relation to surgical treatment. As this is a field in which the authors have made an important original contribution, it is dealt with at greater length than the changes in other pulmonary disease. The authors regret that their references have not been exhaustive, but they give no indication of the principle on which they have made their selection, with the result that in several fields their omissions are such as suggest either that material which has already been dealt with in the literature is original or that their view of current theories is biased. Nevertheless this book will be warmly welcomed by all concerned with heart and lungs.
LETTER CALCIUM B-PAS We were interested to read the leading article in the number of December 1961 (p. 541) concerning Calcium benzoyl PAS but feel that it too strongly supports this drug. The excellent controlled trial by Lees & Allen* is indeed the most worthy assessment of this drug so far. The results, however, were reviewed at six months only and this does not seem to justify their statement that, 'In long-term therapy aimed at preventing relapse, it is therefore both justifiable and advantageous to give calcium B-PAS to patients who prefer it'. Although these regimes were carefully supervised in hospital, which is utterly different from PAS prescribed for home use, it is disturbing to see that 2 cases of drug resistance had developed in each group within 3 months. We consider that these results should be confirmed and that a far more dependable assessment could be made on the second anniversary of the commencement of treatment. Before that time, commendation of Lees & Allen's conclusions in the leading article of the journal of the British Tuberculosis Association, is premature. It is likely that the large majority of patients require only minimal help from anti-tuberculosis drugs and thus minor deficiencies in the taking of PAS will be masked. Unfortunately, we are not able to determine the few who require the most effective long-term therapy to produce recovery and prevent drug resistance. The four instances of drug resistance reported by Lees & Allen within three months on regimes of PAS and isoniazid perhaps add to the view that PAS in any form is indeed a 'second line' drug. Furthermore, investigations designed to determine whether unsupervised patients consume their PAS have all shown that from one third to one half of them do not. We have little doubt that streptomycin and isoniazid under supervision form the dual drug therapy of choice at present and that to depend upon PAS consumption is to deny the facts-with inevitable harm to a small minority of patients. Hammersmith Chest Clinic, London, W. 12.
* Lees, A.
W., Allen, G. W. (1961). Brit, J. Dis. Chest. 55, 185.
PETER STRADLING GRAHAM POOLE