664 5. Rosenberg EB, Strickland GT, Yang SC, Whalen GE. IgM antibody to red cells and autoimmune anaemia in patients with malaria. Am J Trop Med Hyg 1973; 22: 146-52 6 Bouvet E, Lefrancois G, Lebras J, Vroclans M, Simonneau M, Vachon F, Anémié hémolytique auto immune au cours du paludisme immunologique Med Mal Infect 1981, 11: 372-77 7 Gilliand BC, Evans RS. Red cell antibody in acquired hemolytic anaemia with negative antiglobulin serum tests N Engl J Med 1971; 285: 252-56 8. Vroclans M, Dgiminas M, Boivin P Analyse des résultats observés au cours de la recherche d’une auto-sensibilisation anti érythrocytaire chez 2 400 malades. Rev Fr Transfus Immuno-hématolo 1980; 23, 2: 105-17 9. Homberg JC Les anémies hémolytiques avec auto-anticorps In: Hématologie. Paris Flammarion, 1976. 498 10. Costea N, Yakulis VJ, Heller P. Inhibition of cold aglutinins(anti I) by M. pneumoniae antigens. Proc Soc Exp Biol Med 1972; 139: 476-79. 11. Habibi B, Muller A, Lelong F, Honberg JC, Foucher M, Duhamel G, Salmon C. Auto immunisation erythrocytaire dans le population "normale" 63 observations. Nouv Prese Méd 1980; 9: 3253-57. 12 Brown KN, Grundy MS, Hills LA, Jarra W. Cold isohemagglutinins in Plasmodium berghet infected rats reacting with parasitered reticulocytes Bull WHO 1980, 58: 449-57 13. Lustig HJ, Nussenzweig V, Nussenzweig RS Erythrocyte membrane associated immunoglobulins during malaria infection of mice. J Immunol 1977, 49: 210-16 14 Barret-Conner E Plasmodium vivax malaria and Coombs’-positive anemia. Am J Trop Med Hyg 1967; 16: 699-703. 15. Woodruff AW, Ansdell VE, Pettitt LE Cause of anaemia in malaria Lancet 1979 1055: 57. 16 Adam C, Geniteau M, Gougerot-Pocidalmo M, Verroust P, Lebras J, Gibert C. Morel- Maroger L. Cryoglobulins, circulating immune complexe and complement activation in cerebral malaria. Infect Immum 1981; 31: 530-35 17 Masson JS, Miller LA, Shiroishi T, Dvorak JA, McGinnis MH The Duffy blood group determinants: Their role in the susceptibility of human and animal erythrocytes to Plasmodium knowlest malaria. Br J Haematol 1977; 36: 327-35 18 Miller CH. Hypothesis on the mechanism of erythrocyte invasion by malaria mezozoite Bull WHO 1977, 55: 157-62. Preliminary Communication EARLY EXPERIENCE WITH A VERTICAL SPINNING-DISC NEBULISER HILAL MALEM DAVID HENRY MICHAEL WARD W. H. RODERICK SMITH IGOR GONDA Departments of Therapeutics and Respiratory Medicine, City Hospital, Nottingham; and Department of Pharmacy, Aston University, Birmingham Summary A new device for the administration of bronchodilators to asthmatics by nebulis- ation has been developed. Nebuliser therapy, in many patients more effective than other forms of drug delivery, has been limited by the need to provide patients with units driven by compressed air. Solutions can be nebulised by contact with a rapidly spinning horizontal disc. Adaptation of this method to a small nebuliser for clinical use is difficult, since a constant delivery of fluid to the centre of the disc is necessary. The problem has been overcome in the new device in which the disc spins vertically in a reservoir. The performance of the prototype device was compared with that of a conventional compressed air nebuliser. The improvement in spirometry values of 8 asthmatic patients was similar for both nebulisers. INTRODUCTION INHALER therapy in asthma is usually given by pressurised aerosol spray. This is not suitable for young children, and some adult patients teceive suboptimal treatment because of poor inhaler technique.’ Administration of bronchodilators by nebuliser has certain advantages. The continuous aerosol is easy to inhale and appears superior to other methods of drug delivery in reversing airways obstruction.2,3 Domiciliary use of nebuliser therapy is limited by the need to provide compressed air at flow rates of at least 6 1/min. Although small mains and battery powered compressors are available, they are expensive and most weigh more than 3 kg. For active patients these systems are less convenient than pressurised inhalers. We report our early experience with a small nebuliser which can be carried in the pocket, is not driven by compressed air, and operates independently of mains electricity. MATERIALS AND METHODS The ’Nebulet’ (Patent applications: UK, 8109619 PCT/GB81/00055; Spain, 500.713; South Africa, 81/1942)uses the principle that a rapidly spinning disc coming into contact with a liquid will generate an aerosol. 4 Horizontal spinning-disc generators have been used to produce aerosols of uniform particle size for pulmonary deposition experiments.s These sophisticated devices have discs of 3 to 8 cm in diameter driven at speeds of up to 150 000 r.p.m. by air or electric-powered motors. Liquid is fed into the centre of the disc from a constant-height reservoir or syringe pump and spreads in a thin film that accumulates at the edge of the disc because of centrifugal force. A particle is thrown off the disc when centrifugal force exceeds the forces of capillary and surface tension. Particle size is determined by the characteristics of the fluid, the diameter and texture of the disc, and its circumferential velocity. To ensure a uniform aerosol from a horizontally rotating disc, the fluid feed must be central, continuous, and at a constant flow rate. These requirements have been the main obstacles to adapting the principle of the spinning disc to a small aerosol generator. In the nebulet the difficulties were overcome by rotating the disc in the vertical plane through a reservoir containing a drug in solution (see accompanying figure). Larger particles coming off the disc collide with the casing and fall back into the reservoir or on to the disc to be renebulised. Smaller particles are carried by the air current generated by the centrifugal pump, and the size of the particles delivered to the patient is selected by the configuration of baffles in the outlet. The prototype tested weighed 54 g (without batteries). A novel feature is that the device is also capable of delivering drugs in dry powder form. Particle Size The size of the particles generated by the prototype was measured by cascade impactor. The results indicated that when either a saline solution (21% w/v) or micronised disodium cromoglycate powder was nebulised there were virtually no particles over 5 pm in diameter. Approximately 25% of the solution droplets, or 50% of the powder aerosol, had diameters of 1 pm or less. Clinical Studies We compared the performances of the nebulet and the ’Acorn’ nebuliser in a cross-over trial in 8 patients with chronic stable asthma. The acorn riebuliser is a small-capacity disposable unit recommended for use at home. All patients were receiving 9-adrenergic drugs by conventional aerosol inhalers: they were asked to omit their morning doses on each day of the study. 1 ml (5 mg) salbutamol respirator solution was administered by nebulisation to each subject on separate days between 9.00 A M and 10.00 A.M. Therapy was given in random order so that half the patients used the acorn nebuliser first. In every case inhalation was