METABOLIC EFFECTS OF RARE FOOD SUGARS

1419

Letters to the Editor HOW SAFE IS ABORTION ? SIR,-Professor Stallworthy and his team at Oxford (Dec. 4, p. 1245) have indicated that the dangers of terminating pregnancy in their department are very great. It would perhaps be the ethically correct conclusion to draw that all therapeutic terminations of pregnancy in the academic unit at Oxford should cease forthwith; otherwise the interpretation of the clauses in subsection (1) of section (2) of the Abortion Act of 1967 is not correct where such abortions are agreed upon by the professor and his registrars, for the dangers may be greater than continuation of pregnancy. as to the general operation are quite fallacious, and are not based on any general knowledge of the facts. He and his team are to be congratulated, nevertheless, on completing a factual and clinically honest appraisal of their own work. It may well be that general hospitals are not in fact the proper places for these procedures. Mrs. Justice Lane’s committee will certainly consider this paper very carefully. Perhaps the proper solution of the problems involved in the practical interpretation of the Act is for the Department of Health and Social Security to establish abortion units. For, let all opponents of the Abortion Act take note, the

However, Stallworthy’s conclusions

dangers

of the

Lane committee’s terms of reference main provisions of the Act.

are

exclusive of the

The best results are being obtained by surgeons who devote a great deal of their time to treating patients referred to them for abortion, who are sympathetic in their attitude, who understand women, and who do not instil guilt into them. For, surely, most doctors now realise the effect of the psyche on the uterus. The complication-rate must be related to the manner of handling of patients by the gynaecologist, his registrars, and house-officers. The abortion patient may well be regarded as a nuisance, a loose woman, or an object of odium by a number of ward and operating-theatre sisters and their staff. Their rough handling-if not physically, then psychologically-may not only delay recovery but also increase the likelihood of real clinical problems, especially haemorrhage. The Pregnancy Advisory Service has established an abortion unit at Buckhurst Hill, Essex, under the clinical direction of Miss Dorothea Kerslake. We know that our own complication-rate is very much lower than the Oxford unit’s, and have just appointed a further gyntcologist who will, it is hoped, undertake a follow-up of all cases for a proper comparison to be made with Professor Stall-

worthy’s

paper. Professor Stallworthy could have highlighted the real fact that in many, if not all, clinical centres the provisions of the Abortion Act are becoming increasingly difficult to deal with. Widespread dissatisfaction is manifest, both by the public and the profession. The problem is partly to do with shortage of beds and nursing staff, and partly to do with emotional factors which do not operate in other clinical situations. We at Fairfield Nursing Home invite any properly interested doctor to see for himself or herself how our abortion unit functions. We would also welcome any visitors to the Pregnancy Advisory Service in London, to see how a registered charity endeavours to arrange for adequate appraisal of cases referred to them for termination. Pregnancy Advisory Service, 40 Margaret Street, London W.1.

HAROLD PRICE, Medical Secretary.

SHORT-STAY GYNÆCOLOGY WARD SiR,—Iwas stimulated by the letter from Professor Clayton and others (Nov. 27, p. 1197) to look at the pattern of my admissions for the previous twelve months. My ward has 22 beds and an examination-room and the overall bed-occupancy is about 30%. Planned day

Major

cases

operations

Emergencies

868

344

313

The

include D. & c.s, terminations, and planned day surgical simple procedures, such as Bartholin’s marsupialisation. Many of the D. & c.s are done without general anaesthesia, but this form of anaesthetic is usually employed for the termination cases. Nearly all the infertility investigations are arranged on a strictly outpatient basis. The vast majority of this work is performed on two routine theatre lists (twin tables) a week. Staffing the ward produces real problems for the nursing administrators, in that it is very busy for two days a week when the junior nurses get bored with taking patients backwards and forwards to the theatre, and they feel they are making a very poor contribution to the welfare of the patients. At other times there is little to do, since many of the patients (sterilisations and ectopic pregnancies) are discharged after two nights in hospital. I am sure the arrangements at King’s College Hospital are the best for the present-day gynaecological patients, but at the moment there is locally insufficient work to make a viable unit such as theirs. However, now that theatre time is the limiting factor for most surgeons’ work, the " day case ward " with its own theatre attached should help to make the staffing and running of a busy district hospital much easier. cases

3 Roxwell Road, Essex CM! 2LY.

Chelmsford,

G. L. S. RANKIN.

METABOLIC EFFECTS OF RARE FOOD SUGARS SIR,-Although our laboratory has for some years been concerned with the relation between stereochemical structure and physiological effect in the rare food sugars, it is only lately that studies in man have begun to emerge. In particular, lyxose (lethal to rats at normal dietary levels within a few days) bears the same stereochemical relation to mannose (a rare food sugar) as does xylose to glucose (both relatively safe). Mannose administered intravenously (0-5 g. per kg. in 3-5 minutes) is metabolised at a rate similar to glucose in both normal and diabetic human beings.1 In prolonged infusions, however (0-5 g. per kg. per hour, for 10 hours), subjects experienced fatigue, anorexia, malaise, and massive uric-acid crystalluria with deeply orange urine. Two diabetic patients in whom the sugar was infused at the same rate for only 5 hours experienced no subjective change, but in both the plasma-mannose rose to twice the level in normal people after mannose infusion. Xylitol lately became available as a 20% aqueous solution for patients requiring additional calories parenterally, but the preparation has now been withdrawn. Of twenty-three patients receiving intravenous xylitol, eight developed metabolic acidosis, so that 500-900 mmole of sodium bicarbonate was required to restore blood pH to near normal levels. Osmotic diuresis occurred in seven patients, four of whom subsequently developed oliguric renal failure with kidney swelling and deposits of calcium oxalate crystals. Mental effects varied from mild nausea to confusion, stupor, and complete loss of consciousness. Six 1. 2.

Wood, F. C., Cahill, G. F. J. clin. Invest. 1963, 42, 1300. Thomas, D. W., Edwards, J. B., Edwards, R. G. New Engl. J. Med. 1970, 283, 437.

1420 of the

patients subsequently died, and unidentified crystal deposits were found in the brain. I have drawn together some of the physiological illeffects attributable to the rare food sugars (about twenty sugars in all).3 It could be argued that these are so poorly absorbed that metabolic risk does not exist in the average individual. However, an unabsorbed sugar can lead to osmotic diarrhoea, attack by gut microflora, flatulence, and general intestinal disturbance. In view of the above dramatic effects of rare food sugars, ought we not to reconsider their legal status as food additives ? Existing food laws define all sugars as " water-soluble carbohydrates ". This does not seem sufficient to guard against their indiscriminate use. National College of Food Technology, University of Reading, GORDON G. BIRCH. Weybridge, Surrey. CEREBRAL ATROPHY IN YOUNG CANNABIS SMOKERS

SiR,ŅThe argument presented by Dr. Campbell and others (Dec. 4, p. 1219) that consistent cannabis smoking leads to cerebral atrophy in young adults would, I think, fail to convince neuroradiologists unless supported by morbid anatomical evidence. For several decades neuroradiologists have tried (a) to assess the volume of the cerebral ventricles accurately and (b) to determine the upper volumetric limit of normal. In spite of many attempts by a variety of methods they have, in my view, failed to provide a satisfactory answer to either question. One is beset with the great difficulty of relating either a linear measurement or an area (at one particular level in the coronal plane of the ventricles) to ventricular volume. The ventricles, especially the lateral ventricles, which represent most of the total volume, fail entirely to conform to any known geometrical pattern. No formula has yet been devised relating either linear or area measurement to volume. The most accurate estimation of normal ventricular volume was undoubtedly made by the anatomists Last and

Tompsett.4 By taking

every

possible precaution against

brain shrinkage or distortion they made casts of 24 adult and 5 fetal cerebral ventricles. " The evidence ", I quote, " that the brains were normal rests on two points: First, the adult material was obtained at random from autopsies in which the pathologists had no wish to examine the brain, a fact which emphasises the presumptive normality of the intracranial contents. Secondly, no unusual features were found in any of the specimens during the careful removal of the brain substance from around the casts." The volume of the smallest cast was 7-4 ml. and that of the largest 56-6 ml., the average being 22-4 ml. The ages of the patients varied from 29 to 73 years. The smallest cast was in a male aged 38 and the largest in a male aged 42. Ten years ago5 one attempted to relate ventricular volume to linear measurement on radiographs by using Last and Tompsett’s evidence. It seemed that the width of the floor of the cella media was the most reliable linear measurement, but without necropsy support no confirmation of one’s volumetric estimate could be obtained. Another method one tried was to radiograph all Last and Tompsett’s 24 casts and to use them for matching individual cases undergoing air encephalography. Neither method was entirely satisfactory. To return to the findings of Dr. Campbell and his colleagues, they make various assumptions: (1) that because the cross-section of part of the body of the lateral ventricle in 9 of their 10 cases exceeded that of 13 matched 3. 4. 5.

Birch, G. G. Fd Wld, 1969, 4, 5. Last, R. J., Tompsett, D. H. Br. J. Surg. 1953, 40, 525. Bull, J. W. D. Neurology, 1961, 11, 1.

atrophy was present (in their case 9 the left temporal horn only was dilated); (2) that dilatation of one lateral ventricle with a small contralateral ventricle (case 3, fig. 6, and case 4, fig. 7) justified a diagnosis of atrophy. As you say in your leading article (p. 1240): " If ventricular dilatation occurs, histological examination should be able to show the situation and nature of neural damage ". Furthermore, one cannot follow the argument that atrophy might be confined either to one temporal lobe or even one hemisphere, when the alleged toxic agent is presumably blood-borne. I suggest, Sir, that the case is sub judice until a neuropathologist has the opportunity to examine a coronal section of the brain both macroscopically and microscopically. Lysholm Radiological Department, norms,

The National Hospital, Queen Square,London W.C.1.

JAMES BULL.

DETERMINISM AND FREE-WILL

SiR,ŅThis question of whether man is just a machine and that of free-will have filled philosophical volumes, and it is obviously impossible to trace out the ramifications of the arguments in correspondence columns; yet it is of some interest to read the distilled views that represent years of studied thought on the part of different readers. In that spirit I offer the comment that the biologists’ view of this question tends to line it up with the mystery of life. What cannot be explained by the machine theory is not so much free-will as awareness. Is the amaeba aware of being an amoeba ? We do not know. Is the seaanemone, with a network of cells, aware of being a seaanemone ? A dog of being a dog ? We are assured by introspection and comparison of testimonies that a human being is aware of being a human being, and his brain is a similar network to that of a dog, and to some extent the sea-anemone, and his tissues are composed of the same stuff as an amoeba. A machine is also composed of chemicals, but it stretches argument beyond breaking point to imagine that a machine is aware of being a machine. The difference is in being alive. The awareness is largely on the sensory side of the brain, but there are feed-backs to that side from speech and thought. There is thus an immediate premium and reward for the individual in using his mental circuits, because he takes pleasure in the resulting awareness. Even animals indulge in play, exploration, and random activity for similar reasons. This seems to be the most useful way to look at the problem of the Ghost in the Machine-but that brings another myriad of arguments. I conclude that man performs like a machine, but perceives like an ansel. Department of Neurosurgery, Queen Elizabeth Hospital,

Birmingham

p.

B15 2TH.

ERIC TURNER.

SIR,-Much thought has convinced Dr. West (Dec. 11, 1316) that man does not enjoy free-will-and yet he

were right, there would be no point in saying anything, and anything we might say would be without value. The logical contradiction inherent in the determinist hypothesis is in itself enough to prove its falsehood-quite apart from common sense. The logical contradiction is as follows: if I have no free-will, any statements that I may make lack any guarantee of objectivity, including the statement " I have no free-will ". If this utterance is prompted merely by some unconscious compulsion, it has no superiority over a contrary utterance which is also, ex hypothesi, unconsciously determined. The statement " man enjoys free-will " does not suffer from this logical infirmity and, in addition, is in accord with common sense and universal experience. The contradiction in deter-

does !If Dr. West

our