732

newborn infant indeed resembles patients with Wilson’sdisease in having a high level of copper in the liver and adiminished ability to synthesise caeruloplasmin. With the metalstopcocks further potential hazards were residual dried blood,and a white turbidity which was thought to be due to siliconegrease.

In view of these results, replacement of metal stopcocks forexchange transfusions by disposable plastic stopcocks or

exchange-transfusion sets is advocated.Children’s Medical Research Foundation,Royal Alexandra Hospital for Children,

Sydney, New South Wales 2050. JEANETTE BLOMFIELD.

ANTENATAL DIAGNOSIS OF ADRENOCORTICAL

HYPERPLASIA

SiR,-Jeffcoate el aLl have suggested that it is justifiable toexamine the amniotic fluid before term for 17-oxosteroid andpregnanetriol content in the hope of achieving early detectionof adrenocortical hyperplasia in the foetus of a mother whohas already given birth to an affected child. Apart from thedrawbacks associated with the sampling procedure, the resultsobtained would now appear to be inconclusive,2 and thereare distinct advantages if the diagnosis can be made fromanalysis of pregnancy urine. It has been our contention forsome years that adrenocortical hyperplasia in the foetus is

likely to cause increased excretion of oestrogens during preg-nancy, just as foetal adrenocortical hypoplasia entails a verylow oestrogen excretion.3 The opportunity to test this hypo-thesis has only recently arisen, and the results in the firstcase are so striking that they seem worthy of mention.A woman, aged 30 years, had had two previous pregnancies.

The first child was a virilised girl, and congenital adreno-cortical hyperplasia due to 21-hydroxylase deficiency wasdiagnosed in the neonatal period. A second girl was entirelynormal. Urine specimens were collected during the thirdpregnancy, which ended with delivery in the 37th week ofgestation of a second affected child weighing 4-1 kg.-again avirilised girl, with an enlarged clitoris with the opening of theurogenital sinus at its base. On the 9th day of life the 24-hoururinary steroid excretion was as follows: 17-oxosteroids 2-8mg., 17-hydroxycorticosteroids (Few) 5-8 mg., Porter-Silberchromogens 0-65 mg., pregnanetriol (gas-liquid chromato-graphy, upper limit of normal in the laboratory 0-1 mg. per24 hours) 0-63 mg., and 11-oxopregnanetriol 0-29 mg. At theage of 1 month the hydrocortisone secretion during stimula-tion with corticotrophin was 5-02 mg. per 24 hours, or 20-1per sq. m. per 24 hours.The mother’s oestriol excretion at 26, 29, and 34 weeks of

gestation is shown in the accompanying figure, in which it iscompared with the normal values established in the same

laboratory 4: all the values, 26,500 ug., 32,400 ug., and

58,870 ug. per 24 hours, respectively, were clearly higher thanthe upper limit of the normal range. Dr. Mary Coyle’snormal values for oestrone and cestradiol-17B excretion in

pregnancy are to be published elsewhere.5 In this pregnancy,the oestrone-excretion values at 26, 29, and 34 weeks, com-pared with the corresponding values for pregnancy associatedwith a normal foetus weighing more than 2-95 kg. at term,were (normals ±S.D. in parentheses) 532 (730 ±360), 1930

(700 ±410), and 1746 (610 ±440), fLg. per 24 hours, respec-tively. The oestradiol-17p excretion values were (normals±S.D. in parentheses) 601 (200±100), 420 (180±90), and1137 (220 90), ug. per 24 hours, respectively.These results strongly suggest that the diagnosis of con-

1. Jeffcoate, T. N. A., Fliegner, J. R. H., Russell, S. H., Davis, J. C.,Wade, A. P. Lancet, 1965, ii, 553.

2. Merkatz, I. R., New, M. I. Excerpta med. int. Congr. Ser. 1968, 157,175.

3. Cathro, D. M., Coyle, M. G. ibid. 1967, 132, 688.4. Coyle, M. G., Brown, J. B. J. Obstet. Gynœc. Br. Commonw. 1963, 70,

226.5. Cathro, D. M. in Pædiatric Endocrinology (edited by D. Hubble);

p. 218. Oxford, 1969.

(Eestriol excretion of mother of foetus with adrenal hyperplasia.Asterisks represent values given in text.

genital adrenocortical hyperplasia may be made before birthby the standard urinary oestriol assay, which is widely available.Several cases will be required to prove the point but, in themeantime, it is suggested that the urine of mothers at riskshould be routinely assayed for oestriol.

I.N.S.E.R.M., Unite de Recherches, D. METHVEN CATHRO

Hopital Debrousse, Lyon 5e, France. JEAN BERTRAND.Department of Obstetrics and Gynaecology,

University of Dundee, Scotland. MARY G. COYLE.

DISINFECTION OF VENTILATORS

BY ULTRASONIC NEBULISATION

SIR,-It was a pleasure to read the article by Dr. Judd andhis colleagues. 1 We have also been investigating variousmethods of decontaminating inhalation therapy equipment; andwe have arrived at essentially the same conclusions as Judd et al.We further believe this approach, utilising ultrasonic nebulisa-tion of hydrogen peroxide, has broader medical application fordisinfection.We must disagree with the conclusions of Dr. Spencer and

his group. 2 It has been theoretically determined that the

particle size generated by ultrasonic nebulisers bears the

following relationship to surface tension, density, and operatingfrequency:

D cz yl/a . 1 . 1D "(1/.. pI I.. F2/.where: D=particle diameter, y=surface tension, p=density, F=

operating frequency.On the basis of these relationships, we question whether theappreciable difference of the particle size developed by theL.K.B. nebuliser and by the DeVilbiss and Monaghan unitsreported by Spencer is not actually due to different methods ofmeasurement.

The most important physical factors determining nebulisa-tion-rate for a given nebuliser are viscosity and vapour pressure.Tests conducted here have indicated that the DeVilbiss ultra-sonic nebuliser (contrary to Dr. Spencer’s findings) can nebulise1. Judd, P. A., Tomlin, P. J., Whitby, J. L., Inglis, T. C. M., Robinson,

J. S. Lancet, 1968, ii, 1019.2. Spencer, G., Ridley, M., Eykyn, S., Achong, J. ibid. p. 1144.