206 torial suggests, the concept that cerebral infarction and myocardial infarction share a similar underlying xtiology (atherosclerosis). Rather, they challenge the simplistic idea that both are the automatic end-result of a single pathological process. This is particularly true in the case of the modern male epidemic of myocardial infarction, a large part of which could well be the result of an increase in the vulnerability of the myocardium to an inadequate blood-supply rather than a change in the prevalence of disease of the coronary arteries. Department of Preventive Medicine and Biostatistics,

University of Toronto, Toronto, Canada M5S 1A8

TERENCE W. ANDERSON

H.D.L. CHOLESTEROL IN DIABETES MELLITUS

SiR,—Iwas unable

to

agree with all the conclusions of Dr

Calvert and his

colleagues (July 8, p. 66). Before differences serum-high-density-lipoprotein (H.D.L.) cholesterol concen-

in trations in diabetic and normal men and women can be attributed to the diabetes per se, other factors which influence serum H.D.L.-cholesterol concentration and which may differ between different populations must be taken into account. Alcohol intake,I-3 for example, is likely to vary between diabetics who are on carbohydrate-restricted diets and normal controls, especially when these are recruited from the Armed Forces where heavy drinking is traditional. Calvert et al. provide information about body-weight, but it is not body-weight, but obesity which influences serum H.D.L.-cholesterol.4 Thus, weight should have been expressed as body-mass index or percentage of ideal weight so that allowance for height was made.5 The concentrations of serum cholesterol6,7 and triglycerides8 and number of cigarettes smoked,9 all of which influence serum H.D.L.-cholesterol levels, were not included in the paper. The conclusion that sulphonylureas might influence serum-H.D.L. cholesterol is not justified by the study since the groups receiving different therapies were matched only for age, weight, and HbA,. Indeed, the matching for weight does not seem to have been very precise since the S.E.M. for the weight of the sulphonylurea-treated group was very different from that of the other two groups. There was no matching for height, alcohol intake, or serum-lipid concentrations. Perhaps even more important, the treatment which patients were receiving had not been chosen at random, but presumably on the basis of clinical indications. Thus, the patients in each group did not differ solely in their treatment, but also in the degree and type of their diabetes. In another study in which the effect of starting treatment with chlorpropamide was examined there was an increase in serum H.D.L.-cholesterol concentration sustained over one year. 10 In the report by Lopes-Virella and othersl’ cited by Calvert and co-workers, it was concluded that patients with diabetes have lower than normal serum H.D.L.-cholesterol levels. However, their normal controls were unusual in that the distribution of their serum H.D.L.-cholesterol concentrations was positively skewed, despite which Student’s t test was used to compare them with diabetics. I have lately completed a study in which diabetic patients treated with insulin were found to have higher serum H.D.L.1. 2.

Castelli, W. P., and others. Lancet, 1977,

ii,

153.

cholesterol concentrations than normal men and women or diabetics not receiving insulin. The results are still being analysed but differences of the kind which I have discussed are emerging. Non-insulin-dependent diabetics are the most obese and have higher serum M-particle concentrations than the other two groups. They also have the lowest alcohol consumption, the normal group drinking the most alcohol. The heparin-MnCl2 method for estimating serum H.D.L.cholesterol was used in my study. This method gives higher H.D.L.-cholesterol levels than the phosphotungstate-MgCl2 method used by Calvert et al. and Lopes-Virella et al. This is probably because some H.D.L. is precipitated in the phosphotungstate-MgCl2 method, whereas with the heparin-MnCl2 method there may be some incomplete precipitation of H.D.L., and the apolipoprotein-B-containing lipoproteins. In my study the apolipoprotein-B concentration of the supernatants was determined by radioimmunoassay’2 and incomplete precipitation was not found to explain the differences in serum H.D.L.cholesterol observed. Fuller et al.’ found that serum H.D.L.cholesterol levels were highest in those non-diabetic local-government employees with the highest blood-glucose levels and Nikkila has recently reported results in diabetics similar to mine." At present, the most appropriate conclusion from all these studies seems to be that premature inferences must not be made from studies employing precipitation methods for the estimation of serum H.D.L.-cholesterol in diabetes mellitus--especially if other factors influencing serum H.D.L.-cholesterol levels are ignored. A further consideration stems from the finding that insulin-requiring diabetics may be abnormal in the distribution of the H.D.L.1, H.D.L.2 and H.D.L.3 sub-classes which make up total H.D.L.14 H.D.L.2 is considered by some to be the subfraction of H.D.L. reducing the risk of ischasmic heart-disease.15 Measurements of total serum H.D.L.-cholesterol in diabetes are therefore likely to be misleading, if the relationship between H.D.L.2 cholesterol and total H.D.L. cholesterol differs from normal. Futher studies in diabetes should concentrate on ultracentrifugation methods, which are the least likely to add more confusion to an already confused, but, quite probably, important area of medicine. Department of Medicine, Royal Infirmary, Manchester M13 9WL

PAUL DURRINGTON

PITUITARY HORMONES IN DIABETIC KETOACIDOSIS stress the importance of hormones in the of diabetic ketoacidevelopment pituitary dosis. In 1976 we reported a case2 which would emphasise this. A 14-year-old insulin-dependent diabetic female had diabetic ketoacidosis precipitated by a right-lower-lobe pneumonia. 3 years later she was again admitted in typical diabetic ketoacidosis, although on this occasion no obvious cause was found. When 29 years old she underwent local irradiation of the pituitary gland with yttrium-90 for advanced proliferative diabetic retinopathy. 10 months after this procedure she was admitted in severe non-ketotic hyperosmolar coma precipitated by a j3-haemo!ytic streptococcal tonsillitis. This was the second, reported instance of non-ketotic coma in a diabetic after pituitary ablation, the first being described by Kolodny and Sherman in 1968.3 Thus, in clinical practice, after pituitary abla-

SIR,-Dr Barnes and colleagues’

Yano, K., Rhoads, G.G., Kagan, A. New Engl. J. Med 1977, 297, 405.

Johansson, B. G., Nilsson-Ehle, P. ibid, 1977, 298, 633. Carlson, L. A., Ericsson, M. Atherosclerosis, 1975, 21, 417. Gordon, T., Kannel, W. B. Clins. Endocr. Metab. 1976, 5, 367. Fuller, J. H., Jarrett, R. J., Keen, H.; Pinney, S. L. Lancet, 1975, i, 691. 7. Fuller, J. H., Ruskin, H., Jarrett, R. J., Keen, H. Clin Sci mol Med. 1978, 55, 13P. 8. Ewing, A. M., Freeman, N. K., Lindgren, F. T. Adv. Lipid Res. 1965, 3, 25 9. Garrison, R. J., and others. Atherosclerosis, 1978, 30, 17. 10. Paisey, R., Elkeles, R. S., Hambley, J., Magill, P. Clin. Sci. mol. Med 1978, 54, 37P. 11. Lopes-Virella, M. F. L., Stone, P. G., Colwell, J. A. Diabetologia, 1977, 13, 3.

4. 5. 6.

285.

12. 13.

Durrington, P. N., and others. Clinica chim. Acta, 1976, 71, 95. Gotto, A. M, Miller, N. E., Oliver, M. F. (editors) High Density Lipoprotems and Atherosclerosis. Amsterdam, 1978. 14. Gofman, J. W., and others. Plasma, 1954, 2, 413. 15. Anderson, D. W., Nichols, A. V., Pan, S. S., Lindgren, F. T. Atherosclerosis, 1978, 29, 161. 1. Barnes, A. J., Kohner, E. M., Bloom, S. R., Johnston, D. G., Alberti, K. G. M. M., Smythe, P. Lancet, 1978, i, 1171. 2. Campbell, I. W., Munro, J. F., Duncan, L. J. P. Br. J. clin. Pract. 1976, 30, 49.

3 Kolodny,

H.

D., Sherman, L.J. Am. med. Ass. 1968, 203, 119.

207 an insulin-dependent diabetic who develops metabolic decompensation will present with non-ketotic hyperosmolar

tion,

coma

and not with ketoacidosis.

Diabetic and Dietetic



IAN W. CAMPBELL

Department,

J. F. MUNRO L. J. P. DUNCAN

Royal Infirmary, Edinburgh EH3 9YW

PULMONARY TUBERCULOSIS AND BRONCHIAL CARCINOMA

SIR,-Dr Edlin,l in his report of a small series of cases of active tuberculosis unrecognised until necropsy, implied that there was a negative correlation between tuberculosis and carcinoma, and in support of this referred to papers by Fortune (1929)2 and Cooper (1932).3 However, a careful reading of these two papers shows that Fortune’s and Cooper’s conclusions were quite the opposite-viz., that there was no definite correlation between these two diseases-and these papers give no support to the hypothesis that tuberculosis and carcinoma are in some way mutually antagonistic, as originally propounded in 1854 by von Rokitansky4 and later by Pearly In 1955, I described six cases of bronchial carcinoma in association with active pulmonary tuberculosis, distinguishing those in which the carcinoma developed in known cases of pulmonary tuberculosis from others in which tuberculosis was first discovered when the carcinoma was diagnosed.6 I forecast that we would probably see more patients with these two diseases in association. Springett later showed that pulmonary tuberculosis and bronchial carcinoma not uncommonly coexist, and possibly more often than by chance. The explanation of this has been controversial. Some maintain that carcinoma may develop in scar tissue at sites of healed tuberculous disease.8-10 Alternatively, healed tuberculous lesions may be invaded by carcinoma and the tuberculous disease become reactivated.6 While I agree with Dr Howie’s view on this matterll I cannot accept the suggestion of Dr Healy 12 that "tuberculosis is a common opportunist infection in patients with carcinoma of the lung". In opportunist infection, the offending organism is not a usual human pathogen, and its proliferation results from diminished host defences. However, Mycobacterium tuberculosis is pathogenic to man, and it is therefore incorrect to apply the term "opportunist infection" in this context. Redhill General Hospital, Redhill, Surrey RH1 6LA

***This

letter has been shown

A. SAKULA

to

Dr

Edlin, whose reply fol-

lows.-ED.L.

SIR,-Dr Sakula equates "negative correlation" with Both Fortune and Cooper found a negative correlation between carcinoma and tuberculosis, but also showed statistically that this was due, not to mutual antagonism, but to death from tuberculosis before the individual would have developed carcinoma. My basic point was that carcinoma was not of value as a marker of occult tuberculosis, as

"antagonism".

1. 2.

Edlin, G. P. Lancet, 1978, i, 650. Fortune, C. H. Ann. intern. Med. 1929, 3, 495. 3. Cooper, F. G.Am. Rev. Tuberc. 1932, 25, 108. 4. von Rokitansky, C. A. Manual of Pathological Anatomy;

vol I,

p. 313. Lon-

don, 1854. 5. Pearl, R. Am. J. Hyg. 1929, 9, 97. 6. Sakula, A. Br. med. J. 1955, i, 739. 7. Springett, V. H. Tubercle, 1971, 52, 73. 8. Cherry, T. Lancet, 1931, i, 285. 9. Woodruff, C. E., Nahas, H. C.Am. Rev. Tuberc. 1951, 64, 620. 10. Wofford, J. L., Webb, W. R., Strauss, H. K. Arch. Surg. 1962, 85, 928. 11. Howie, A. J. Lancet, 1978, i, 881. 12. Healy, T. M. ibid. p. 1267.

leukaemia and other reticuloses have been associated with tuberculosis. 1,2 This does not affect the question of the coexistence of tuberculosis and carcinoma. Previously tuberculosis was a disease of youth, but in my series the average age of death with active tuberculosis was 67.4 as opposed to 67.8 for controls. My apparent rate for active tuberculosis not causing death was 1 in 400 necropsies, so a clinician seeing a large number of cases of bronchial carcinoma can expect to see it with the frequency of that age-group (in Dundee 1 in 400) rather than at the rate of incidence in the general population, and so may gain a false impression of its frequency. Pathology Department, Royal Hampshire County Hospital, Winchester

G. EDLIN

ITALY’S ABORTION LAW

SIR,-Your Round the World correspondent3 is misleading.

Italy’s new law does not permit "abortion on demand" in the first 90 days of pregnancy. Abortion is only allowed within 90 days if continuing the pregnancy would involve a serious danger to the women’s physical and mental health or if there is serious risk that the child would be deformed. The term "serious" is not defined and so is open to the widely varying interpretations of individual doctors. 90% of doctors in Rome and over 70% of doctors in Florence have publicly stated that they will not participate in terminations, so, while the law grants legal abortion, the medical profession is denying it. Your R.T.W. item suggests that women have the right of decision up to 90 days. In fact this is far from what is stated in the law which requires the doctor to determine the consequences of not having a termination. The dioxin incident at Seveso was not considered by local doctors to constitute a serious danger, even though the evidence shows that dioxin can cause severe fetal malformations. One section of the law states that the father of the conceived child can accompany the woman to discuss the abortion in front of the doctor unless the woman objects. Only self-confident women will feel able to object, while many will feel embarassed and confused as two men discuss the question of terminating her pregnancy. If an abortion is requested on social or economic grounds, the doctor must first attempt to remove these grounds by informing the woman about adoption, charitable organisations, help for single mothers, and so on-and only after a thorough investigation would he be able to grant her request for termination. You implied that, once termination has been agreed to, the woman then has 7 days to think about it, after which she is admitted to hospital. This is not true. She has first to return to the original doctor and argue for her decision again. This is, for women, one of the most humiliating aspects of the new law-because it assumes that pregnant women do not know their own minds and must be compelled to rethink. As a counsellor for a C.I.S.A. (information centre on sterilisation and abortion) my experience is that women who apply for a termination have already been through the arguments and made up their minds. The 7-day rule is simply a way of increasing the length of time it takes to get a termination-and the only person who will suffer will be the woman herself. The woman’s problems are not over even if the doctor agrees after the statutory 7 days. She then has to join the queue for a Health Service termination (no private clinics). Since doctors object and many hospitals are run by nuns and

Fortunanto, A Gazz. Osp. Clin. 1931, 59, 843. Ulrich, H., Parks, H. New Engl. J Med. 1940, 222, 711. 3. Lancet, 1978, i, 1252. 1 2.

Pituitary hormones in diabetic ketoacidosis.

206 torial suggests, the concept that cerebral infarction and myocardial infarction share a similar underlying xtiology (atherosclerosis). Rather, the...
310KB Sizes 0 Downloads 0 Views