1381 mice (3 weeks old) after intracerebral inoculation and blind passage at two week intervals. The same material did not produce plaques on Vero cells incubated under methylcellulose but could be preserved by storage with whole cells at —70°C. There was no increase in the titre of MSafter sonication of infected cells (20 s at 4°C) and the maximum dilution possible for transmission was 10-3. In an attempt to identify the MSlagent, indirect immunofluorescence was performed using Vero-infected cells and antisera against the following viruses: measles, respiratory syncytial, herpes, bovine and monkey foamy, mumps, and rubella. We also used adult human serum, serum from a patient with subacute sclerosing panencephalitis, serum from three MS patients and hyperimmune serum prepared against MSinfected Vero cells. None of the above produced immunofluorescence. Thus, out of ten MS marrow samples tested, one produced a definite transmissible cytopathic effect. We do not believe it was caused by a mycoplasma related to M. hyorhinis or M. laidlawii and it does not seem to be a readily recognisable virus. Although there is the possibility that we have merely transmitted a cytotoxic factor this seems most unlikely, in view of the considerable dilution involved. Dense bodies similar to those shown have been described in chronic experimental allergic encephalomyelitis lesions and in MS plaques,7 where it was suggested these "membrane specialisations" may represent biological errors, and as a cell surface coat of hamster fibroblasts.8 The nature of their appearance in MS1infected cultures suggest that they could either be derived from mycoplasma or dead cells. If there is a transmissible cytopathic agent in MS bone-marrow, then our results indicate that it is either a non-recognised mycoplasma or an agent which produces an abortive and nonperpetuating infection in the systems so far tested.

ERNEST A. GOULD* ALFREDO CHIARINI EVELYN DERMOTT KENNETH C. MCCULLOUGH STANLEY HAWKINS HAROLD MILLAR

Department of Microbiology, Queen’s University of Belfast, Belfast, Northern Ireland Department of Neurology, Royal Victoria Hospital, Belfast

*Present address: Field Research Station, London School of Hygiene and Tropical Medicine, Winches Farm, Hatfield Road, St. Albans, Hertfordshire.

HÆMODIALYSIS IN SCHIZOPHRENIA has been reported to be beneficial for schizophrenics9-11 but of no value in other cases. 12-1" Since these studies have been uncontrolled and because of the important implications for treatment and for research we wish to report preliminary results of a double-blind controlled study of hsemodialysis in schizophrenia. With their informed consent, twelve patients diagnosed as schizophrenics15 were randomly assigned to active dialysis (seven) or sham dialysis (five). An 8 day washout period was

SiR,—Haemodialysis

some

’

7.

Appearances.

(a) Vero cells infected with MS1 at pass 5. (b) Uninfected cell control. (c) Electronmicroscopy of thin section of Vero cells infected at pass 5 with MS1 showing elongated dense bodies lying on the surface or being pinocytosed (arrows). (x44 000.) (d) As (c) but dense bodies are visible between contiguous cell membranes (arrows). (x 5000.)

450 nm and 200 nm filters but not always through 100 nm membranes. Freeze-thawed material from MS1infected Vero cells (pass 5) produced no signs of illness in white

through

Raine CS. Membrane specialisations between demyelinated axons and astroglia in chronic EAE lesions and multiple sclerosis plaques. Nature

1978; 275: 326-27. Hynes RO, Rowlatt C, Sandall JK. Cell surface coat of hamster fibroblasts. Ann NY Acad Sci 1978; 312: 221-39. 9. Thölen VH, Stricker E, Feer H, Massini MA, Staub HD. Uber die anwengund der kunstlichen niere bei schizophrenie und myasthenia gravis. Dtsche Med Wochensch 1960, 85: 1012-13. 10. Wagemaker H Jr, Cade R. Hemodialysis in chronic schizophrenia. Am J Psychiat 1977; 134: 684-85. 11. Cade B, Wagemaker H. Hemodialysis as treatment for chronic schizophrenia. Abst Am Soc Artif Intern Organs 1978; 7: 7. 12. Kroll PD, Port FK, Silk KR. Hemodialysis in schizophrenia, a negative report. J Nerv Ment Dis 1978; 166: 291-93. 13. Port FK, Kroll PD, Swartz RD. The effect of hemodialysis on schizophrenia: a survey of patients with renal failure. Am J Psychiat 1978; 135: 743-44. 14. Weddington WW, Ferris GN. Can dialysis help the chronic schizophrenic? 8. Graham JM,

15.

Am J Psychiat 1977; 134: 1310-11. Feighner JP, Robins E, Guze SB, Woodruff RA, Winokur G, Munoz R. Diagnostic criteria for use in psychiatric research. Arch Gen Psychiat 1972; 26: 57-63.

.

1382 CHANGES IN SCORES

(A

SCORES;

MEAN±SEM)

IN SCHIZOPHRENIC

FREQUENCY

OF ANGINAL ATTACKS BEFORE AND AFTER ASPIRIN

PATIENTS AFTER ACTIVE OR SHAM DIALYSIS

ADMINISTRATION

9 A.M. to 9

*

tp0.05). - BPRS scores significantly improved after AD p