1131

after treatment with chemotherapy including teniposide; none of the four children received radiotherapy. These cases appear to constitute a unique syndrome characterised by 11q23 chromosomal abnormalities, a short latent interval (1-6 years, median 3 years), and initial responsiveness of the second malignancy to induction treatment.1-s We observed two patients (one with NHL and the other with neuroblastoma) in whom AML developed 14 and 15 months after treatment with chemotherapy that included an epipodophyllotoxin; both had an 11q23 abnormality and responded to induction treatment. Although they have mutagenic (carcinogenic) potential6,’ the epipodophyllotoxins have a broad range of antineoplastic activity and have improved treatment outcome in patients with a variety of malignant neoplasms. The challenge now is to identify patients who are at especially high risk of therapy-related AML and factors that might increase the carcinogenic potential of the

epipodophyllotoxins. St Jude Children’s Research Hospital, Memphis, Tennessee 38101, USA, and Memphis College of Medicine, University of Tennessee

recurrence in the family would be underestimated. Once the molecular genetics of this condition is understood an easier, more reliable test should be developed.

Wessex

Regional Genetic Counselling Service, Department of Child Health, Southampton General Hospital, Southampton SO9 4XY, UK

I. K. TEMPLE

Department of Genetics, Hospitals for Sick Children, London

M. BARAITSER

Mothercare Department of Genetics, Institute of Child Health, London

M. E. PEMBREY

Department of Cytogentics, Queen Elizabeth Hospital, London

L. BUTLER

Wessex General

P.JACOBS

Genetics

Regional Laboratory, Hospital, Salisbury

Institute of Molecular Medicine, John Radcliffe Hospital, Oxford 1.

K. E. DAVIES

Oostra BA, Hupkes PE, Perdon LF, et al. New polymorphic DNA marker close to the fragile site FRAXA. Genomics 1990; 6: 129-32.

CHING-HON PUI

Chocolate and the auto-brewery syndrome L, Mott MG, Mann JR, et al. Second malignancies in children treated for non-Hodgkin’s lymphoma and T-cell leukaemia with the UKCCSG regimens. Br J Cancer 1987; 55: 463-66. 2. Pui C-H, Behm FG, Raimondi SC, et al. Secondary acute myeloid leukemia in children treated for acute lymphoid leukaemia. N Engl J Med 1989; 321: 136-42. 3. Ratain MJ, Kamier LS, Bitran JD, et al. Acute nonlymphocyric leukaemia following etoposide and cisplatin combination chemotherapy for advanced non-small-cell carcinoma of the lung. Blood 1987; 70: 1412-17. 4. DeVore R, Whidock J, Hainsworth JD, et al. Therapy-related acute nonlymphocytic leukaemia with monocytic features and rearrangement of chromosome 1 1q. Ann Intern Med 1989; 110: 740-42. 5. Prieto F, Palau F, Badia L, et al. 11q23 abnormalities m children with acute nonlymphocytic leukaemia (M4-M5) associated with previous chemotherapy. Cancer Genet Cytogenet 1990; 45: 1-11. 6. Long BH, Musial ST, Brattain MG. Single- and double-strand DNA breakage and repair in human lung adenocarcinoma cells exposed to etoposide and teniposide. Cancer Res 1985; 45: 106-12. 7. DeMarini DM, Brock KH, Doerr CL, et al. Mutagenicity and clastogenicity of teniposide (VM-26) in L5178Y/TK +/--3.7.2C mouse lymphoma cells. Mutat Res 1987; 187: 141-49 1. Ingram

Unusual

presentation of fragile X syndrome referred for genetic

was

Mars BV, 5466AE Veghel, Netherlands

A.

VAN

LIESHOUT

counselling because their

SIR,-A family daughter, who was moderately developmentally delayed, was diagnosed as having the fragile X syndrome. In the daughter 28% fragile sites were demonstrated in a peripheral lymphocyte culture were

shocked to read on the front page of the Dutch De Telegraaf of Oct 5 that eating too much chocolate newspaper could cost a driver his licence. Under the heading "Dronken door chocolade" (drunk through chocolate) the newspaper cited a note in your Oct 6 issue (p 872). The same message was broadcast in a radio programme on the morning of Oct 5. The article in the Journal of Nutritional Medicine, on which your note was based, states that the 510 volunteers were patients attending for investigation of a variety of disorders and in whom chronic gut candidiasis or gut fermentation was already suspected clinically. Do you have evidence that this "auto-brewery syndrome" occurs in healthy people? If not, why did you not refer to the special character of the test group? It is most unfortunate that the linking of the test substance (glucose) with chocolate and the omission of the special character of the test group prompted a newspaper article likely to mislead the general public.

SIR,-I

and 16% in a repeat culture. Clinical examination of the child was incompatible with the diagnosis. The parents were concerned about their younger son. Early developmental milestones and speech were delayed. At age 3 years and 7 months his functional age was assessed as 2 years. On examination his head circumference was on the 29th centile and facial features were unremarkable but in keeping with the presumed diagnosis of fragile X syndrome. However, chromosome analysis showed that he had a normal male karyotype with no evidence of fragile sites. Two further separate lymphocyte cultures looking at over 100 cells at two different centres did not reveal fragile sites. His mother and father were of normal intelligence and had normal chromosomes. That the mother was a carrier was confirmed when her sister opted for prenatal diagnosis for fragile X. The male fetus proved to have 4-4% fragile sites, which confirmed that both women were obligate carriers of the condition. The family proved informative for the closely linked probe pRNl. This had been shown to have a 5% recombination rate with the disease locus.’ The results have shown that both the sister and her brother have inherited the same allele from their mother. The most obvious interpretation of these results is that the brother does have the fragile X syndrome, although fragile sites cannot be

demonstrated. There are few documented cases of this unusual finding, especially in a young retarded boy. This case should alert clinicians to the possibility that there are instances where fragile sites cannot

be demonstrated in an affected male. Such circumstances would be especially worrying in an isolated retarded male where the risk of

Fetal neural

graft survival

SiR,—The report by Dr Redmond and colleagues (Sept 29, p 820) of the post-mortem analysis of fetal neural grafts in a patient with end-stage parkinsonism is an important step in the evaluation of this procedure as a potential treatment. It is reassuring to learn that the grafts contained viable neurons which formed synapses. Nevertheless, the apparent absence of tyrosine-hydroxylase (THase) positive cells within the grafted tissue is disappointing, although many of the cells were reported to contain neuromelanin granules, suggesting that they might have been dopaminergic. The description by Redmond et al of the intracaudate mesencephalic grafts is, in some respects, reminiscent of the picture that can be found in the substantia nigra of patients with Parkinson’s disease. Thus, in the brains of parkinsonian patients, nigral cells have been found which contain neuromelanin but not THase and which have significantly lower levels of THase mRNA than control brains.1 The reduced levels of THase mRNA are not related to duration of disease, age, or levodopa therapy. However, the effect of disease severity is unknown.’A reduction of THase mRNA has also been found in the remaining nigral dopamine neurons of rats subjected to chronic 6-hydroxydopamine lesions.2 The reduction of THase mRNA in both of these situations may result from damage sustained during compensatory hyperactivity of surviving neurons.2,3 By analogy, one might speculate that the lack of THase immunoreactivity in the cells grafted to the parkinsonian brain reported by Redmond et al may also have resulted from cell damage following a period of compensatory metabolic hyperactivity. Another interesting finding which may support this possibility was the presence of neuromelanin in some grafted cells. Neuromelanin in human embryos (developing in situ) does not

1132

normally appear in the substantia nigra dopamine neurons until 18 months of age.’ The "premature" appearance of neuromelanin in the implanted fetal cells may be indicative of metabolic overactivity and premature ageing.4 Alternatively, its presence may reflect cellular damage by quinones and oxygen radicals generated by

Experiments were done with enriched extracts of D pteronyssinus spent growth medium (20 mg/ml) and with purified Der pI (0-3 mg/ml). Both agents were added to the apical side of the epithelium. The proteinase activities of the two preparations were first assayed by ’Azocoll’ degradation and then matched for use in the chamber

auto-oxidation of dopamine,’ although the significance of neuromelanin in dopamine cells as either a pathological marker of Parkinson’s disease or a possible cause of Parkinson’s disease is dubious.6 Redmond’s report reinforces the worrying possibility that the grafts may have been subjected to similar process(es) to those that caused parkinsonism in the first place. The effect of the degree of severity of the disease is important. The patient had end-stage parkinsonism. Did any of the fetal dopamine cells in the grafts or in the host substantia nigra described by Redmond et al contain anything resembling Lewy bodies?7

studies. Incubations were also done in the presence of 1-5 mmol/l dithiothreitol to render the cysteine proteinase catalytically competent. The results demonstrate that Der pI can increase bronchial permeability to serum albumin (and presumably other macromolecules). Further experiments are required to investigate the time and concentration-dependency of these effects and whether inert Der pI can be activated by reducing agents in the airways.’ However, these preliminary results reinforce the hypothesis that allergens may enhance airways disease by means other than their antigenic activity.

Parkinson’s Disease Society Research Laboratories,

Immunopharmacology Group, Pharmacology and Medicine 1, Southampton General Hospital, Southampton SOB 4XY, UK

C. A. HERBERT S. T. HOLGATE C. ROBINSON

University Department of Medicine, Queen Elizabeth II Medical Centre, and Western Australian Institute of Child Health, Perth, Western Australia

P. J. THOMPSON G. A. STEWART

Clinical

Pharmacology Group, Biomedical Sciences Division, King’s College, London SW3 6LX, UK

S.B.BLUNT

1. Javoy Agid F, Hirsch EC, Dumas S, Duyckaerts C, Mallet J, Agid Y Decreased tyrosine hydrolase messenger RNA in the survival dopamine neurons of the substantia nigra in Parkinson’s disease: an in situ hybridization study. Neuroscience

1990; 38: 245-53. 2. Pasinetti GM, Lemer SP, Johnson SA, Morgan DG, Telford NA, Finch CE. Chronic lesions differentially decrease tyrosine hydroxylase messenger RNA in dopaminergic neurons of the substantia nigra. Mol Brain Res 1989; 5: 203-09. 3. Hornykiewicz O, Kish SJ. Biochemical pathophysiology of Parkinson’s disease. Adv Neurol 1986; 45: 19-34. 4. Mann DM, Yates PO. Lipoprotein pigments—their relationship to ageing in the human nervous system II: the melanin content of pigmented nerve cells. Brain

1974; 97: 489-98. 5. Cohen G. Monoamine oxidase, hydrogen peroxide and Parkinson’s disease Adv Neurol 1986; 45: 119-25. 6 Marsden CD. Neuromelanin and Parkinson’s disease. J Neural Transm 1983; 19 (suppl): 121-41 7. Forno LS. Pathology of Parkinson’s disease. In. Marsden CD, Fahn S, eds. Movement disorders. London: Butterworths, 1982.

1. Chua

KY, Stewart GA, Thomas WR, Simpson RJ, Dilworth RJ, Plozza TM. Sequence analysis of cDNA coding for a major house dust mite allergen, Der pi, homology with cysteine proteases. J Exp Med 1988; 167: 175-82. 2. Stewart GA, Thompson PJ, Simpson RJ Protease antigens from house dust mite Lancet 1989; ii: 154-55. 3. Stewart GA, Lake FR, Thompson PJ. Faecally-derived hydrolytic enzymes from the house dust mite: characterization of potential allergens. J Allergy Clin Immunol

(in press) CA, Summers JA, Robinson C. In vitro techniques for the study of transepithelial protein flux in the airways and its modulation by inflammatory cells and mediators. Br J Pharmacol 1990; 100: 477P. 5. Herbert CA, Edwards D, Boot JR, Robinson C. Modulation of eosinophil-induced enhancement of bronchial epithelial permeability. Br J Pharmacol 1990; 100: 373P. 6. Heffner JE, Repine JE. Pulmonary strategies of antioxidant defense. Am Rev Respir 4. Herbert

Dis 1989; 140: 531-54

Effect of mite allergen on permeability of bronchial mucosa SIR,-The allergen Der pI from the house dust mite Dermatophagoides pteronyssinus is a cysteine proteinase in which the antigenic epitopes are distinct from the catalytic site. 1-3 As a development of our studies suggesting that proteinases disrupt the bronchial epithelium to augment transmucosal macromolecule movement we postulated that the enzymatic activity of Der pI might enhance the access of antigens to immunocompetent cells in the asthmatic airway by a similar mechanism. We have tested this hypothesis with an in vitro model in which sheets of bovine mounted between two heated halfpermit defined 02 cmz areas of tissue to be exposed to bathing solutions on either side. The apical sides of the tissues were exposed for 3 h to the various treatments (table). The net apical-basolateral flux of 12sI-Iabelled bovine serum albumin was then measured after replacement of the medium with fresh proteinase-free buffer.

bronchial mucosa chambers4 which

are

EFFECT OF SPENT GROWTH MEDIUM AND DER pl ON APICAL-BASOLATERAL FLUX OF ALBUMIN IN BOVINE BRONCHIAL MUCOSA

*In fmol cm - 2 mln - 1, as mean (SEM), p values refer to appropriate controls tUnlts/ml with azocoll substrate

SGM =spent growth

medium DTT=drthiothrertol

Extracorporeal membrane oxygenation SIR,-Dr Greenough and Dr Emery (Sept 22, p 760) suggest that at King’s College Hospital there would be a likely requirement for extracorporeal membrane oxygenation (ECMO) in 1/5000 births if predicted mortality rates of 80% were applied. They go on to say that of the 5 infants who seemed to be suitable, 3 survived without problems and the remaining 2 died following rapid collapse. Bartlett et all in Michigan estimated 1 infant per 1000 livebirths would be saved by ECMO each year according to these same criteria. With colleagues I wished to validate a projected figure of 20 infants a year in South Australia, having studied ECMO use. The medical records of infants between 34 weeks’ gestation and 12 months of age and between 2 and 10 kg in weight who died in Adelaide paediatric intensive care units between July, 1981, and June, 1986, were reviewed to see how many might have been considered for ECMO had it been available as a clinical service. Criteria for such consideration included reversible disease, artificial ventilation for less than seven days, and no intracranial haemorrhage. An additional criterion was that 90 min could have elapsed for an ECMO circuit to be established. In this five years there were 126 deaths of which 40 might have been considered for ECMO had it been available. Deaths were classified according to the system affected and whether the disease was acquired or congenital. In the largest group (acquired pulmonary disease), 25 of 33 would certainly have been considered for ECMO whereas in only 1 of 15 congenital pulmonary deaths might this have been beneficial. Nearly all these deaths were due to pulmonary hypoplasia. All 4 infants dying from acquired cardiac disease could have benefited from the use of ECMO whereas in only 3 of 21 infants dying from congenital heart disease would ECMO have been considered. There were no ECMO appropriate deaths involving other systems; and most (75%) were in the neonatal

period.