1092

72 h, but no benefit ensued. Fernando et al. pre-treated theiranimals with heparin which might have influenced the out-come. The addition of heparin to our regimen had no effect.Our observations lend no support to the notion that inosine

might be of value in acute renal failure in man.

Department of Nephrology,St. Bartholomew’s/St. Leonard’s Hospitals,London

L. R. I. BAKERW. R. CATTELLM. SENSI

NASAL C.P.A.P. IN MANAGEMENT OF RECURRENTAPNŒA

SIR,-Our observations confirm those of Dr Speidel and DrDunn (Oct. 23, p. 914) that an infant receiving nasal con-tinuous positive airway pressure respiration (C.P.A.P.) is not

usually in the mouth-open state.We would confirm their report (Sept. 25, p. 658) of the effi-

ciency of nasal C.P.A.P. in reducing the frequency of apnceicattacks in the preterm neonate. In some resistant cases we havefound intermittent positive-pressure "ventilation" (i.P.P.v.) bynasal catheter of value. i.P.P.v. is administered in combinationwith nasal C.P.A.P. usually at a rate of seven to ten breathsper minute, at a pressure of 10-20 cm H20 and a C.P.A.P. of2-8 cm H2O.

In several infants endotracheal intubation has been avoidedbv use of this technioue.

Pædiatric Department,Simpson Memorial Maternity Pavilion,Edinburgh EH3 9EF I. L. SWANN

MACROPHAGES AGAINST CANCER

SIR,—You drew attention (July 3, p. 27) to the role macro-phages may have in the defence against tumours. Since themacrophage seems to be able to discriminate between neoplas-tic and non-neoplastic’ it would be the prime candidate for acell operating in a surveillance mechanism.2 The lack of im-munological specificity might be irrelevant. Discussion of thepotential of the macrophage would be incomplete, however,without noting that macrophages can also suppress lympho-cyte functions.3 In vitro, macrophages suppress not onlyT-lymphocyte stimulation by mitogens4 and alloantigensS butalso antitumoral immune responses.6 You have pointed to thedangers of immunotherapy not being based on knowledge ofthe underlying mechanisms. Immunotherapy of humantumours very often fails,8 and in selected animal models "im-munotherapy" has actually promoted tumour growth.9 10 It isconceivable that in these instances cellular immunity is sup-pressed by overstimulation of macrophages. The "doctor’sdilemma" may be how to stimulate the phagocyte withoutoverstimulating it.

Institute of Virus Research,German Cancer Research Centre,6900 Heidelberg, West Germany HOLGER KIRCHNER

1. Hibbs, J. B. Jr., Lambert, L. H. Jr., Remington, J. S. Nature new Biol. 1972,235, 48.

2. Currie, G. Biochim. biophys. Acta, 1976, 458, 135.3. Nelson, D. S., Shneider, C. N., Penrose, J. M. in Mitogens in Immunobio-

logy (edited by J. J. Oppenheim, and D. L. Rosenstreich), p. 477. NewYork, 1976.

4. Kirchner, H., Chused, T. M., Herberman, R. B., Holden, H. T., Lavrin,D. H. J. exp. Med. 1974, 139, 1473.

5. Fernbach, B. R., Kirchner, H., Bonnard, G. D., Herberman, R. B. Trans-plantation, 1976, 21, 381.

6. Glaser, M., Kirchner, H., Herberman, R. B. Int. J. Cancer, 1975, 16, 384.7. Kirchner, H., Glaser, M., Herberman, R. B. Nature, 1975, 257, 396.8. Magrath, I. T., Ziegler, J. L. Br. med. J. 1976, i, 615.9. Piessens, W. F., Lachapelle, F. L., Legros, N., Heuson, J. C. Nature, 1970,

228, 1210.10. Che, D. O., Bodurtha, A. J. Int. J. Cancer, 1974, 14, 137.

HÆMODIALYSIS IN ACUTE LIVER COMA

SIR,— Dr Knell and Dr Dukes (Aug. 21, p. 402) proposeusing haemodialysis in the treatment of acute liver coma. Thistechnique allows the correction of the electrolyte and acid-basedisturbances and renal-function changes often found in liverfailure.

Hxmodialysis can also remove from the blood metabolitessuch as aminoacids, false neurotransmitters, mercaptans, andammonia which are involved in the pathogenesis of encephalo-pathy and liver coma. For example we achieve significantclearances of plasma aminoacids during haemodialysis using arecirculating single-pass system with 1 m2 coil Bentley AltlOO(18 µm cuprophan membrane), blood-flow 200 ml/min.

In practice the situation is not as good as it seems fromtheoretical data. We have done 72 haemodialyses lasting 4-8 hon sixteen patients with encephalopathy or in grade 2-4 livercoma.’ Our experience is encouraging but still not conclusive:in general the results seem better the earlier hxmodiatysis isdone and the less critical is the patient’s condition. A transientimprovement of neurological condition has always beenobserved by us and by Opolon’s group.2 3 No hemorrhageshave occurred during dialysis or during the subsequent 24 hexcept in patients already bleeding.

Until more efficient treatments are available, we think thatdialysis is one of the best techniques available in these cases,and we agree with Dr Knell and Dr Dukes in suggesting itsapplication on a larger scale.

First Medical Clinic,University of Milan,20122 Milan, Italy

F. QUARTO DI PALOG. BUCCIANTIE. E. POLLI

IgM RUBELLA-ANTIBODY TESTING AFTERPASSIVE TRANSMISSION OF ANTIBODIES

SIR,-A pregnant woman who was suspected of having hadcontact with rubella was passively immunised with 40 ml of’Rubeuman Berna’ (Schweiz. Serum- und Impfinstitut, Bern).10 days later her blood was sent to our laboratory for estima-tion of rubella IgM antibodies. The test was positive but we didnot know whether the passively transmitted antibodies alsocontained rubella IgM antibodies or not.

RUBELLA H.I. ANTIBODY TITRES AFTER PASSIVE IMMUNISATION

WITH RUBEUMAN IN VOLUNTEERS A AND B

N.D.--not done

Rubeuman is an immunoglobulin preparation from conva-lescent sera with a high rubella-antibody titre. After separationof 1 ml rubeuman on an agarose column4 the fraction nor-mally containing IgM antibodies had a haemagglutination-in-hibiting (H.I.) titre of 1/32. However, in the radical immuno-diffusion test of this fraction no IgM but only IgG could befound. We concluded that the preparation contained IgGaggregates which had about the same molecular weight as IgMand therefore would give a false-positive rubella IgM titre.

1. Quarto di Palo, F., Civardi, F., Buccianti, G., Polli, E. E. Paper read to theEuropean Society for Artificial Organs, in Berlin, in November, 1975

2. Opolon, P., Lavellard, M. C., Crubille, C., Gateau, Ph., Nusinovici, V., Granger, A., Darnis, F., Caroli, J. Nouv. Presse méd. 1975, 4, 2987.

3. Opolon, P., Lavallard, M. C., Grubille, C., Gateau, Ph., Nusinovici, V.,Granger, A., Darnis, F., Caroli. J. Paper read to the European Societyfor Artificial Organs, in Berlin, in November, 1975.

4. Burgin-Wolff, A., Hernandez, R., Just, M. Lancet, 1971, ii, 1278.