1117

We believe our approach avoids these ethical difficultiesand will yield an answer more quickly. We leave the choiceof drug to the clinician, and only that drug is assessedagainst the patient’s tumour growing in mice. Relativelyfew human tumours transplanted to mice are materiallydamaged by drugs (fig. 2), and relatively few cancer patientsshow a worth-while degree of tumour destruction by drugs.The question we have set ourselves is: are the few tumoursthat respond in the patients the same as the few that respondin the mice ? If so, the screen will be validated and canthen be used predictively, and a considerable improvementwill be possible in patient selection for chemotherapy andtherefore in the results of therapy. The problem is simpli-fied by the fact that clinicians tend to use only one or twodrugs in any one type of cancer, so that it is not so much aquestion of deciding what drug to use as which patientsto use it on.

This work is in progress and we would be pleased to receivetumours sent to us for this purpose.

M. C. BERENBAUMC. E. SHEARD.

Wellcome Laboratories ofExperimental Pathology,

Variety Club Research Wing,St. Mary’s Hospital Medical School,

London W.2.

COMPARISON OF LIVER SCANSAND LIVER SNAPS

HAROLD O. CONN.

Department of Internal Medicine,Yale University School of Medicine,New Haven, Connecticut 06510,

U.S.A.

SiR,-It is unfortunate that the introduction of theterm " liver snaps " in England (April 29, p. 929) as

an informal term to describe liver images produced bythe gamma camera coincides with the introduction of thename Liva Snaps ’ in America to describe a luxury dog-biscuit. Despite the excellence of the observations fromSt. Thomas’s, it may be difficult for Americans to takeEnglish " liver snaps " very seriously, and vice versa.

PROPRANOLOL IN ESSENTIAL TREMOR

J. C. SHEE.Bulawayo Central Hospital,

Bulawayo, Rhodesia.

SIR,-Dr. Pakkenberg (March 18, p. 633) recorded

partial success with propranolol in the treatment of thisintractable condition. His patients were in the age-range56-78 years. Morris et al. remarked that alcohol sometimesgives temporary relief often with rebound exacerbation.A not infrequent story is that of the businessman who

has to have two or three tots of spirits before being able tosign the outgoing mail or weekly cheques.One of the difficulties in the assessment of remedies is

the absence of clear diagnostic criteria, as evidenced by 4 ofPakkenberg’s suspected cases who later developed park-insonism.

In view of the improvement sometimes observed fromingestion of alcohol, I tried the effect of various otherpsychotropic drugs in patients suspected of the condition.

In an open trial on 6 patients, who included 2 juveniles,medazepam in doses of from 5 to 10 mg. thrice dailyseemed to give improvement of the same order as thatdescribed by Dr. Pakkenberg for propranolol.

SiR,—I have a patient with essential tremors who hasbeen taking propranolol (20 mg. twice a day). His tremorshave been substantially reduced. He has, however, notedthat at night he has to get up several times to go to emptyhis bladder. On some occasions he has forgotten to take1. Morris, C., Prange, A., Jr., Hall, C., Weiss, E. Lancet, 1971, ii, 165.

his evening dose of medication. On those nights he has noneed to get up. I am not aware of any report of thisside-effect. He has no other side-effects and is respondingsatisfactorily now to 20 mg. three times a day.

ALI H. RAJPUT.University Hospital,

Saskatoon, Canada S7N 0W8.

CAROLI’S TRIAD

DOMINIQUE FROMMEL.

Department of Pædiatrics,University of Paris V Medical School,

Paris 15e, France.

SIR,—I hope that the English description, therefore theacceptance, of a " new " triad (April 29, p. 964), is reflectingthe traditional British sense of humour and not a new policyof The Lancet towards Europeanisation in medical termin-ology. Do not let The Lancet become an ABC of eponyms,for we rather like to have it as a guide in keeping abreastwith actual medicine.

AUSTRALIA ANTIGEN INAMNIOTIC FLUID

S. MATSUDAK. TADAR. SHIRACHIN. ISHIDA.

Department of Bacteriology,Tohoku University School of Medicine,

Sendai, Japan.

SiR,—The solid-phase radioimmunoassay (R.I.A.), whichwas introduced by Abbott Laboratories as Ausria-125 kit, 1was used to detect Australia (Au) antigen in amniotic fluidand cord sera obtained from 59 parturient women. Eachof the maternal sera was tested for Au antigen by immuno-electrosyneresis (I.E.S.) under a blind condition. Theresults were:

Incidentally, 3 positive amniotic fluids were obtainedfrom 3 parturient women whose sera were Au-positive.When each of these 3 amniotic fluids was mixed with ahuman serum containing Au antibody and incubated at37 °C for 1 hour, for blocking test, the original positivehigh counts (723, 823, and 1129 c.p.m., respectively) werereduced to the level of the negative control value.Although it is too early to determine the significance of

this finding, our results may suggest a new way of verticaltransmission of Au antisen.

INSECT VECTORS IN SERUM HEPATITIS

SIR,-Insect-borne transmission of hepatitis-associatedantigen (H.A.A.) has been suspected from epidemiologicaldata in South-East Asia. 2 Transmission by insects is

theoretically possible since minute amounts (10-7 ml.) ofH.A.A. serum have been shown to be infectious.3 We hadrecently the opportunity to observe an epidemic of H.A.A.-positive hepatitis in our dialysis unit.4 4 In this context

suggestive evidence was obtained that transmission of

H.A.A.-positive hepatitis may have occurred in some casesby way of cockroaches. This possibility was tested experi-mentally by raising American cockroaches (Periplaneta

1. Matsuda, S., Igarashi, H., Umenai, T., Sasaki, T., Ishida, N.Tohoku J. exp. Med. (in the press).

2. Blumberg, B. S., Sutnick, A. I., London, W. T., Millman, I.New Engl. J. Med. 1970, 283, 349.

3. Sanwald, R., Ritz, E., Rapp, W., Andrassy, K., Kommerell, B.Ger. med. Mon. 1970, 9, 502.

4. Barker, L. F., Shulman, N. R., Murray, R., Hirschman, R. J.,Ratner, F., Diefenbach, W. C. L., Geller, H. M. J. Am. med. Ass.1970, 211, 1509.