433 were intended as an assessment of outthe widely held view (fully supported by the Indeed, results of some controlled trials’) that the effects of E.C.T. are rather slow to emerge, such a finding would have been very plausible. The fact that such differences were not observed must be weighed against the significant differences seen at the end of week 1 in evaluating the results of the trial. The problem with previous trials on patients with depression is not that they have "failed to show real E.C.T. to be superior to stimulated treatments" but that, as in the case of the well-known trial of Cronholm and Ottosson,2which reported a positive finding, the design did not exclude the possibility that biases in patient allocation to treatment group could have given a spurious result. Freeman and colleagues have failed to emphasise the discrepancy between their own conclusion and that of Lambourn and GilP4 who compared the effects of real and simulated, unilateral E.C.T. using a stronger design (6 real against 6 simulated treatments) in a similar number of patients with severe depressive illness. The results showed no more differences between the groups than could be expected by chance. Dr Freeman properly draws attention to the ethical aspects of trials of E.C.T. Such considerations apply not only to the conduct but also to the interpretation of such studies.
Division of Psychiatry, Clinical Research Centre,
Harrow, Middlesex HA1 3UJ
T. J. CROW EVE C. JOHNSTONE C. D. FRITH
STEVENS-JOHNSON SYNDROME DURING TREATMENT WITH CIMETIDINE
SIR,-A 38-year-old Asian woman with a history of penicillin allergy was given cimetidine 800 mg daily by her general practitioner. On the 25th day of treatment she felt a burning sensation in her eyes and noted redness of the outer angles. She stopped taking the tablets. On the following day the ocular symptoms increased, her lips became red, painful, and swollen, and she had fever and a rash on her arms, legs, and trunk. She attended her general practitioner, and after 10 days was referred to us. We noted a fading papulo-purpuric rash on her arms, legs, and trunk. Both palpebral and bulbar conjunctivee were congested. There was a marked symblepheron near the outer angles of both eyes. No membrane was seen and the cornea was not affected. The mucous membrane of the upper and lower lip and mouth was excoriated, leaving a raw and bleeding surface. The exposed surface of the lower lip had a crust of congealed blood. There was no evidence of vaginal or urethral involvement, and her temperature was normal. Investigations showed Hb 12.5g/dl, reticulocytes 0-7%, white-blood-cell count 9380/1 (54% neutrophilis, 37% lymphocytes, 6% monocytes), platelets 150 000/1. Bleeding-time was normal and Hess’s test negative. Urinalysis was negative. Cimetidine was the only drug which the patient was taking before the onset of the Stevens-Johnson syndrome. Neither could we find evidence of any other precipitating factor. To be sure that cimetidine was the cause of the problem we would have had to challenge the patient with the drug; however, we felt that this was ethically unjustifiable. The Stevens-Johnson syndrome is thought to have an allergic basis,s and in view of a report6 that treatment with Hz-receptor antagonists may be associated with augmentation of delayed-hypersensitivity responses it is possible that cimetidine was the precipitating factor in our patient. 1.
R. N., Bruce, A., Johnstone, E. C., Lader, M. H. Lancet, 1974, ii, 731. 2. Cronholm, B., Ottosson, R. O. Acta psychiat. scand. suppl. 145, 35, 69. 3. Lambourn, J., Gill, D. Br. J.Psychiat. 131, 317. 4. Lambourn, J., Gill, D. ibid. (in the press). 5. Fitzpatrick, T. B., and others (editors). Dermatology in General Medicine; p. 559. New York, 1971. 6. Avella, J., Rinder, H. J., Madsen, J. E., Askenase, P. W. Lancet, 1978, i,
We suggest that the incidence of side-effects of cimetidine in patients such as ours, with a history of allergic problems, merits further study. A. H. AHMED Muhimbili Medical Centre, D. G. MCLARTY P.O. Box 20693, S. K. SHARMA University of Dar es Salaam, Tanzania
A. E. J. MASAWE
VIRUS-LIKE PARTICLES IN PREGNANCY URINE
SIR,-After the demonstration by Coleman et al.’ of JC polyomaviruses in the urine of a pregnant woman, we examined the prevalence of these viruses in pregnancy urine locally, using negative-staining electronmicroscopy of urine pellets after high speed centrifugation. In a series of 300 urine specimens in pregnancies varying from 7-41 weeks, we detected polyomavirus in 10 specimens (3.3%). 15 of the specimens (5%) contained a second, vesicle-associated particle with a diameter of approximately 35 nm which appears to develop in association with the membranes of the vesicle. Morphologically, it does not resemble any known human virus, having a clearly defined double shell with an obvious substructure (see figure). We have not detected similar particles in approximately 2 500 urine specimens from non-pregnant patients.2 3 patients were positive for both polyomavirus and the second particle. The majority of the latter particles were "empty" although some "full" particles were also found. The significant occurrence of this particle, its structure, and its intimate association with membranous vesicles suggests that it is viral in nature and is an agent to which pregnant women are susceptible. The "in fection" appears to be subclinical with no apparent effect on the mother, although a role in neonatal pathology cannot be ruled’ out. It probably occurs more frequently than was shown in our survey because low concentrations of the particle would be missed by electronmicroscopy. Efforts to grow the "agent" in tissue culture are continuing in our laboratory and follow-up studies on patients and their offspring are in pro1. 2.
Coleman, D. V., Daniel, R. A., Gardner, S. D., Field, A. M., Gibson, Lancet, 1977, ii, 709. Lecatsas, G., van Wyk, J. A. L. S. Afr. med. J. 1978, 53, 787.
434 gress. If the
particle proves to be a virus, we propose "prsegna-
as a name.
Departments of Microbiology and Obstetrics and Gynæcology, University of Pretoria and H. F. Verwoerd Hospital, Pretoria, South Africa
G. LECATSAS HEATHER CREW-BROWN ELSJE BOES INGRID ACKTHUN J. PIENAAR
that a "deficiency in nerve supply does not interfere with normal development". The transplanted wing buds "attracted" nerve fibres from the host and the nerve fibres which entered the transplant became enlarged to accommodate the increased demand for nervous function. He further demonstrated that the patterning of the nerves within the limb is determined by the transplanted limb bud and not the host
embryo. The three studies cited above demonstrate that:
SIR,-McCredie and her colleaguesl-6 have attempted
reduction malformations of limbs on the basis of to neural-crest cells resulting in subtraction of one or more sclerotomes in the limbs. 1-6 The argument runs: "Assuming a trophic function of embryonic sensory peripheral tissue (neural crest and its derivatives), failure of growth of part of a limb or viscus might be explained by failure of trophic stimulus by the nerve supplying, that part". They suggest that thalidomide embryopathy is due to initial damage to the neural crest with subsequent malformation of the limbs. A critical test of McCredie’s hypothesis would be as follows: a limb bud which has not yet received innervation and which can be demonstrated to contain no neural-crest cells or neuralcrest derivatives, grafted to a location where no neural-crest cells or derivatives can innervate it, should not have the capacity of normal development. Westoncarefully recorded the temporal changes during neural-crest-cell migration. With the use of tritiated-thymidine-labelled cells which had been grafted into host embryos adjacent to the postaxial half of the wing bud of chick embryos, he demonstrated that, although active migration of neural-crest cells in that region could be observed as early as stage 16,8 the cells did not migrate into the limb bud until at least stages 21-23. The first labelled cells approaching the limb could be seen "... extending from the mid-dorsal line to the dorsal margin of the wing bud", by stages 21-23. These were interpreted by Weston as being melanoblasts. Eastlick9 transplanted limb buds from chick embryos ranging in age from 55 to 70 days (stages 15-18) to the coelom of host embryos. These transplants, even the oldest ones, were accomplished before the stage when Weston first observed labelled neural-crest cells approaching the limb bud. Donor limb buds from pigmented varieties were obtained which developed unpigmented plumage when isolated from the neural crest (coelomic grafts), suggesting that no melanoblasts had reached the limb buds before transplant. Slightly more than 50% of the limbs that developed were normal in appearance (i.e., exhibited the normal number of digits). Although melanoblasts do not represent the sensory nerve component of neural crest cells, this study demonstrates that limbs isolated before any neural-crest cells enter them are capable of normal development. Similar results were obtained by Rawleslo after transplanting mouse limbs into chick coeloms. Of even greater importance are 583 limb-bud transplants described by Hamburger" in 1939. This paper summarised transplants of limb buds to the coelom and body wall of host embryos. Careful consideration was given to nerve patterns in the transplants, and both innervated and nerveless limb buds were observed. Hamburger noted that "Nerveless transplants were found to be as perfectly developed as innervated ones"; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
McCredie, J. Lancet, 1973, ii, 1058. McCredie, J. Med. J. Aust. 1974, 1, 159. McCredie, J. J. Neurol. Sci. 1976, 28, 373. McCredie, J. Birth Defects orig. Art. Ser. 1977, 13, 65. McCredie, J., McBride, W. G. Clin. Radiol. 1973, 23, 204. McCredie, J., Reid, I. S. J. Pediat. 1978, 92, 762. Weston, J. A. Devel. Biol. 1963, 6, 279. Hamburger, V., Hamilton, H. L. J. Morph. 1951, 88, 49. Eastlick, H. L. J. exp. Zool. 1939, 82, 131. Rawles, M. E. Proc. natn. Acad. Sci. U.S.A., 1940, 26, 673. Hamburger, V. J. exp. Zool. 1939, 80, 347.
ROLE OF NEURAL CREST AND PERIPHERAL NERVES IN LIMB DEVELOPMENT
crest cells or their derivatives do not enter the limb bud to stage 21-23; stage 16-20 limb buds can be isolated from the neural crest or its derivatives and result in limbs which and (3) there have to normal size and
is a relationship between development of the limb and size and distribution of peripheral nerves. This relationship, however, is determined by the limb and not by the neural crest. A hypothesis of limb malformations based upon a primary defect in the neural crest is therefore not tenable. Neural-crest cells or peripheral nerves are not required for normal development of the limb. The development of models to explain malformations is praiseworthy, but it is a pity that investigators today tend to overlook important contributions of the past.
Supported in part by grant HD00836 from the National Institute of Child Health and Human Development. Central Laboratory for Human Embryology, Department of Pediatrics, School of Medicine, University of Washington, Seattle, Washington 98195, U.S.A.
TRENT D. STEPHENS
CŒLIAC LUNG DISEASE AND INFLUENZA VACCINATION
SIR, There have been several reports of diffuse interstitial
lung disease in association with adult coeliac disease, 12 but the relationship of the two conditions and the relevance of avian antibodies remain speculative.34 We have seen a patient with adult coeliac disease in whom diffuse interstitial lung disease developed after he was inoculated with influenza vaccine produced in chicken embryo. A 57-year-old man presented with a 9-month history of weight loss and diarrhoea. Investigations revealed malabsorption and subtotal villous atrophy. He had serum antibodies to a wide range of food products, including chicken serum. Chest X-ray was normal. He was put on a gluten-free diet, and over the next 2 months his general condition and a repeat jejunal biopsy showed improvement. 6 months later he received an influenza vaccination (’Influvac’) from his general practitioner. 6 h after this he awoke shivering, breathless, and with a severe non-productive cough. These symptoms persisted for 2 weeks before his readmission. On admission he was pyrexial (39-4°C) and chest X-ray showed pronounced diffuse bilateral mottling of the lung fields. The white-blood-cell count was normal and no pathogenic organisms were isolated from sputum or blood. Over the next 2 weeks he was treated with three different antibiotics but his symptoms, chest X-ray, and pyrexia remained unchanged. In view of the temporal relationship with the influenza vaccination and in the knowledge that he had serum antibodies to chicken, the possibility of a type-3 allergic reactiori to the chicken embryo in the vaccine was considered. Lung-function tests confirmed a restrictive defect and marked impairment of transfer factor (Tlco 3.2kPa mmol-1 min; expected 8.3 ± 1 - 7). He was prescribed prednisolone 60 mg/day, and within 12 h he was apyrexial. The improvement was maintained and over the following 6 weeks the chest X-ray returned to normal. Similar improvement was seen in transfer factor 1.
Lancaster-Smith, M. J., Benson,
K., Strickland, I. D. Lancet, 1971, i,
473. 2. 3. 4.
Robinson, T. J. Br. med. J. 1976, i, 745. Eade, O. E., Berrill, W. T. Lancet, 1978, i, 1262. Purtilo, D. T., Bonica, A., Yang, J. P. S., ibid. 1978, i, 1359.