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tion. They attributed this inhibition to Haemaccel, a plasma expander used in the heart-lung machine. We have found, however, that heparin also strongly inhibits ristocetin-induced platelet aggregation. In our in-vitro experiments by the turbidimetrical method using heparin PRP (250 U/1) aggregation due to ristocetin in a concentration of 1 g/l was completely abolished by this substance, while with 1-5 g ristocetin/l the inhibitory effect of heparin started at a concentration of 10 kU/l and was completed at 25 kU/i. In blood obtained from 10 normal individuals after an intravenous injection of 5000 U of heparin there was a slight impairment of aggregation with ristocetin (1-5 g/l), while with 1 g ristocetin/l platelet aggregation was abnormal. We conclude therefore that heparin as well as Haemaccel must play a part in the inhibition of ristocetin-induced platelet aggregation in patients undergoing cardiopulmonary bypass. Y

PEKgELEN

S INCEMAN Department of Haematology, Clinic of Internal Medicine, Istanbul Medical Faculty, (papa, Istanbul, Turkey

Serum digoxin in patients with thyroid disease SIR,-The paper by Dr M S Croxson and Professor H K Ibbertson (6 Septemrber, p 566) was an interesting study of drug metabolism in thyroid disease. The low serum digoxin levels in thyrotoxicosis are probably due in part to increased clearance of the drug, as suggested. But a much more important factor may be that of malabsorption, which was not adequately investigated. It is known that a high percentage of patients with thyrotoxicosis have steatorrhoea.' Digoxin is a steroid molecule and poorly soluble in water. It is therefore very probable that malabsorption of digoxin accompanies the steatorrhoea of thyrotoxicosis. Unfortunately Dr Croxson and Professor Ibbertson measured digoxin excretion in only two patients with thyrotoxicosis and no control values were given, so we feel that there is little evidence to support their suggestion that malabsorption does not play an important role in the low serum digoxin levels in thyrotoxicosis. This aspect obviously needs further investigation, especially as the results may have implications for other drugs given to patients with thyrotoxicosis. KENNETH WATTERS

within 10 days. I checked this fact with the Liverpool School of Tropical Medicine. When faced with a patient showing symptoms and signs suggestive of rabies there may be clear-cut evidence that the dog was ill and died of its illness. Rabies becomes probable. If the history is of no dog bite, or a bite by a dog that was not ill and that was known to be alive 10 days afterwards, rabies is nevertheless still a possibility because of the unreliability of negative evidence. But the question whether there has been inoculation of the virus often arises WVhen someone is bitten or has contact with an ill dog. Here the state of the animal is of essential importance. If alive it must be compounded and kept to see if it dies within 10 days. All too often a dog is killed in anger, ignorance, or misplaced zeal, although there may be circumstances when it is too mad to be caught and kept alive. It must not be destroyed or buried. A post-mortem examination is obligatory, and of course this is most likely to give reliable results if the dog has died naturally. If it cannot be proved that the dog was free from rabies, then prophylactic injections must be given to the patient and others at risk, even though they are often painful and hazardous. I raise this as only last week a patient asked about a bite from a dog "from Germany." The dog was alive and well and had been in quarantine, so I was able to reassure them that there was no danger of rabies. J E PARRY Kirkham

SIR,-Your timely leading article on the diagnosis and management of human rabies (27 September, p 721) was extremely interesting. However, I believe it would also be very desirable to hear from one of our veterinary colleagues on public health aspects of the disease in animals in view of the spread of rabies across Europe. Many people think of animal rabies only in terms of the furious form of the disease, whereas in the tropical countries in which I have served I think it was the animal with the dumb form which was more dangerous because the state of the animal could not be immediately recognised. H B L RUSSELL University Departnent of Community Medicine, Ecinburgh

Controlled trial of therapy in Reye's

G H TOMKIN syndrome

Metabolic Unit, Adelaide Hospital, Dublin 1 Thomas, F B, Caldwell, J H, and Greenberger, N J, Annals of Internal Medicine, 1973, 78, 669.

Rabies SIR,-In your leading article on the diagnosis and treatment of human rabies (27 Septem-

ber, p 721) you do not include the valuable evidence that can often be obtained about the animal. The state of the dog, for example, is very relevant in making a correct diagnosis. When I worked in Zambia I learnt to ask all about the "mad" dog. If it is rabid it dies

SIR,-Your timely leading article on Reye's syndrome (20 September, p 662) correctly emphasises the importance of considering this diagnosis in any child with convulsions and coma. Since the pathophysiology of this condition is so poorly understood the value of the various forms of therapy which have been advocated for this condition can be decided only by well-conducted controlled trials. A major problem in instituting such trials is the comparative rarity of the condition, its sporadic frequency, and its varying severity. None of the forms of therapy mentioned in the leading article have been subjected to such controlled trials. For that reason we are co-operating in a multicentre

JOURNAL

11 OCTOBER 1975

controlled trial organised by the department of paediatrics of Yale University in conjunction with some eight units. Four treatment regimens are being assessed, supportive treatment as outlined in your leading article being compared with similar supportive measures aided by (a) exchange transfusion, (b) peritoneal dialysis, and (c) glucose and insulin infusion. We would be pleased to supply further details of the trial protocol to clinicians who would wish to participate in this trial. May we through your columns also ask any pathologists or clinicians to preserve serum, urine, and liver tissue from such patients, preferably at a temperature of -70°C, so that these may be available for analysis as the pathophysiology of this condition is elucidated? ALEX P MOWAT King's Ccllege Hospital London SES

B G R NEVILLE

Guy'c Hospital, London SEI

SI units

SIR,-Among doctors divorced from the hierarchy of the teaching hospitals and pure science there is an overwbhelming feeling that we are being conned into accepting the introduction of SI units as an advancement in medical technique. One district after another in Kent through their district medical committees have already sent resolutions of protest and at least one district pharmaceutical committee and the area medical advisory committee have similarly protested. There are no reasons to suppose that the introduction of SI units will benefit the patient or improve the results of investigations interpreted through ST units; indeed, the reverse is likely to occur, with possible disastrous results to the patient. The undue haste with which this scheme is being introduced will bring intolerable pressures on both the medical and nursing professions, and it seems highly unlikely that reeducation of such large numbers can be completed in time. That such a scheme should be introduced at this time of financial strineency and shortage of all grades of hospital staff to meet the whims of scientific bureaucrats and none else seems quite incredible. We readily support our colleagues on these other committees and ask that in the interests of the patient and the country the introduction of SI units shall be postponed, possibly for even as long as five years. A F CRICK Honorary Secretary, Dartford. Gravesend, and Medway Division, BMA

Grave-end, Kent

Effects of exertion on hormone secretion SIR,-In addition to the investigations presented in our previous letters (29 June 1974, p 726; 21 June 1975, p 685) we decided to assay plasma growth hormone (GH) before and after exertion in the remaining sera from the group of amateur Finnish marathon runners. The determination of GH was performed with a double-antibody solid-phase technique. Mean control values were 07 (range 0O2-2-8) ,ug/l and after the run the mean value was 5 4 (range 1-3-11-2) ,g/l.

BRITISH MEDICAL JOURNAL

11 OCTOBER 1975

The very fit man had the highest rise, from 0 9 to 10 9 ,ug/I. In contrast, the level in the older Greek runner remained virtually unchanged (0-8 and 1-0 ,g/l). Our investigation confirms the significant rise of plasma GH previously reported after physical exercise.'-3 This work is one of a series of studies on the effects of physical exercise on plasma hormones and muscular metabolism. We hope to find tests to distinguish in advance between men who are fit enough to run the marathon and those for whom it may be dangerous.4 That such tests may be necessary has already been demonstrated by the case of Philippides, the dispatch-runner who died on arrival at Athens after the Battle of Marathon on 22 September 490 BC.5 SIRKKA-LIISA KARONEN H ADLERCREUTZ University Department of Clinical Chemistry, Meilahti Ho'pltal,

A DESSYPRIS University Endocrine Research Unit, Minerva Foundation, Helsinki, Finland Sutton, J et al, Medical 7ournal of Australia, 1972, 2, 127. Hartley, L H, et a!, journal of Applied Physiology, 1972, 33, 607. 3 Sutton. J R, et al, British Medical 7ournal, 1973, 1, 520. 4 Kavanagh, Tr, Shephard, R H, and Pandit, V 7ournal of the American Medical Association, 1974, 229, 1602. 5 Fowler, H W, and Fowler, F G (trans), The Works of Lucian of Samosata, vol 2, p 36. London, Oxford University Press, 1949. 1

2

Pregnancy in adolescence SIR,-Your leading article "Pregnancy in adolescence" (20 September, p 665) has prompted me to write about Hayward House, which is one of a number of family group homes run by the Messenger House Trust. Hayward House was opened in March 1975 for young West Indian mothers aged 14 to 18 years in order that they may keep their babies. There is an increasing number of these schoolgirls who do not wish to give their babies for adoption, who have been rejected by their families, and who in the normal course of events return to school while their children are placed in residential nurseries or foster homes and are reclaimed by the mothers when they are of schoolleaving age. In our experience in these circumstances no normal bonding between mother and child has developed; in one case a much damaged child of 4 years was in due course given up for adoption and in another the toddler, having returned to the mother, suffered severe bums before being taken away from the mother. In contrast Hayward House is a happy place where five girls care for their children and at times for each other's, and with home tuition it is hoped that these mothers will mature and in due course be able to manage in council flats at the age of 18. Some may make early marriages, and with our system of aftercare perhaps be successful in bringing up their families in a more adult manner than without the care of the voluntary visitors and the work that we have done together at our large group meetings, which are held with the mothers from the other houses and with members from the social services also present. I feel that many similar small houses should be leased to voluntary bodies by the local authorities where these young mothers

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could live and that this is an effective way likely to reflect the underlying disease process of preventing emotional damage to young than is the clinical presentation. children. We shall be opening our next D R DAVIES house, to be named after the late Dr Donald J R TIGHE Winnicott, in the next few months. Further N F JONES particulars may be obtained from the address St Thomas's Hospital Medical School, London SE1

below. JOSEPHINE M LOMAX-SIMPSON Messenger House Trust, 17 Malcolm Road, London SW19 4AS

"Caecal squelch" and appendicitis SIR,-At times the differential diagnosis of acute appendicitis is difficult. The history of diarrhoea or headaches and the finding of a high fever (>39-5°C), inflamed fauces, and diffuse lymphadenopathy are well-known features that point away from the diagnosis of acute appendicitis. We would like to emphasise an additional sign which we have found very helpful in deciding whether an appendicectomy is necessary-when a "caecal squelch" is palpable in the right iliac fossa an acutely inflamed appendix is unlikely to be present. During the past 18 months over 400 patients with the possible diagnosis of acute appendicitis have been seen by one surgical team at this hospital. The presence or absence of fluid bowel contents that "'squeldh" on pressing in the right iliac fossa has been particularly noted. During this time there were only three patients who had a ;'caecal squelch" and who subsequently had acutely inflamed appendices removed. These three all had otherwise characteristic histories and signs of appendicitis. Significantly, they all had a distal appendicitis, the proximal parts being macroscopically normal. B V PALMER Whipps C.roqs Hospital, London ElI

1 Davies, D R, et al, 7ournal of Clinical Patho!ogy, 1973, 26, 672. 2 Berger, J, et al, Actualites nephrologiques de l'Hopital Necker, 1967, 172.

Prescriptions for pill

SIR,-It may be helpful to draw to the attention of doctors who are used to giving prescriptions for six packets of the pill at a time the fact that there are 13 menstrual months in a calendar year. On the basis of being given two six-monthly prescriptions patients will return at the end of the year, a month before they are eligible to complete another Form FP 1001. In our practice we intend to issue a seven-month prescription between 1 January and 30 June each year in order to try and avoid this pitfall. D S JEFFERY Old Windsor

Fibrinogen uptake scanning SIR,-In Dr V C Roberts's plea for standardisation of the interpretation of the fibrinogen uptake test (23 August, p 455) we find several aspects in which his experience differs from our own, although our techniques of leg reading appear to be identical. In the first place, our patients receive their dose of 125I-fibrinogen immediately after operation and we cannot therefore compare postoperative with preoperative readings. Secondly, we find background radiation negligible and readings virtually the same with and without reference to this parameter. More fundamentally, however, the pattern of leg counts in our patients without isotopic evidence of venous thrombosis is significantly different from his. Our own figures are taken from the records of 50 randomly selected patients. We have averaged the six-day percentage counts at each of 10 points on the leg and deduced the standard errors of means from the means of the standard deviations. The mean counts in our patients at positions 1, 2, 3, 4, 5, and 9 differ significantly from his (the t values being 4-81, 6-11, 4-27, 2-00, 2-00, and 2 56 respectively). The six-day means (SEM in parentheses) in Dr Roberts's series are: 31 (1-2), 28 (10), 27 (1-0), 27 (09), 27 (09), 28 (1-0), 29 (1-0), 29 (10), 28 (10), and 26 (10) compared with our figures of 41 (17), 39 (1-5), 34, (1-3), 30 (1-2), 30 (1-2), 30 (1-2), 27 (12), 26 (1-2), 24 (1-2), and 23 (1-3). In our experience it is usual for the percentage counts to fall progressively from groin to ankle. A V POLLOCK MARY EVANS

Isolated glomerulonephritis with mesangial IgA deposition SIR,-In their paper on this subject (13 September, p 611) Dr J G P Sissons and his colleagues are incorrect in claiming that "no other series has been reported from this country." We reported the occurrence of recurrent haematuria and mesangial IgA deposition in a paper given to the Pathological Society in January 1973. The features of six patients with this clinicopathological association were reported in the 7ournal of Clinical Patholocy.l At this hospital between 1971 and 1975 the association of recurrent haematuria with mesangial IgA deposition was seen in 16 (7 0) out of 220 renal patients whose biopsy specimens were examined by immunofluorescent techniques (transplants excluded). "Entities" are notoriously ill-defined in nephrology, but recurrent haematuria with mesangial IgA is seen sufficiently frequently for it to be given a special place. Until the aetiology and pathogenesis have been clariScarborough Hospital, fied "Berger's nephropathy" seems a useful Scarborough, N Yorks eponym for this association of recurrent

haematuria with mesangial IgA.2 It seems likely that other patients with mesangial IgA deposition and "isolated glomerulonephritis" but who present with symptoms other than haematuria also belong to this group. The pattern of immuno-

Methods of laparoscopic sterilisation SIR,-We read with interest Dr G Hughes and Mr W A Liston's retrospective comparison of laparoscopic tubal diathermy and globulin deposition in the glomeruli is more abdominal tubal ligation (13 September, p