143 4. Black RE, Lopez de Romana G, Brown KH, Bravo N, Balazar OG, Kanashiro HC. The incidence and etiology of infantile diarrhoea and major routes of transmission in Huascar, Peru. Am J Epidemiol 1989; 129: 785-99. 5. Elegbe IA, Ojofeitimi EO. Early initiation of weaning and proliferation of bacteria in Nigerian infants. Clin Pediatr 1984; 23: 261-64. 6. Gordon JE, Chinese ID, Lyon JB. Weanling diarrhoea. Am J S Sci 1963; 245: 345-77. 7. Rowland MGM, Barrell RAE, Whitehall RG. Bacterial contamination in traditional Gambian weaning foods. Lancet 1978; i: 136-38. 8. Esrey SA, Feachem RG. Interventions of the control of diarrhoeal diseases among young children. Promotion for Food Hygiene 1989; WHO/CDD/89.30. 9. Nyaga PM, Kagiko MM, Gathuma JM. Milk hygiene in nomadic herds in Kenya evaluated by bacterial isolation, bacterial viability trials in traditionally fermented milk and drug sensitivity. Bull Animal Health Prod Afr 1982; 30: 19-24. 10. Tomkins AM, Alnwick D, Haggerty P. Fermented foods for improving child feeding in eastern and southern Africa: a review. In: Alnwick D, Moses S, Schmidt OG, eds. Improving young child feeding in Eastern and Southern Africa: household level food technology. Proceedings of a workshop. Nairobi, 1988: 136-167. 11. Mensah PPA, Tomkins AM, Drasar BS, Harrison TJ. Effect of fermentation of Ghanaian maize dough on the survival and proliferation of 4 strains of Shigella flexneri. Trans R Soc Trop Med Hyg 1989; 82: 635-36. 12. Sakoane AL, Walsh A. Bacterial properties of traditional sour porridges in Lesotho. In: Alnwick D, Moses S, Schmidt OG, eds. Improving young child feeding in Eastern and Southern Africa: household level food technology. Proceedings of workshop. Nairobi, 1988: 136-67. 13. Nout MJR, Hautvast JGAJ, Van der Haar F, Marks WEW, Rombarts FM. Energy, protein and microorganisms: the formulation and microbiological stability of cereal-based weaning foods. In: Alnwick D, Moses S, Schmidt OG, eds. Improving young child feeding in Eastern and Southern Africa: household level food technology. Proceedings of workshop. Nairobi, 1988: 245-260. 14. Harrigan WF, McCance ME. Laboratory Methods in Dairy Microbiology. London: Academic Press, 1976. 15. Thatcher FS, Clark DS. Microorganisms in foods. Vol I. Their significance and methods of enumeration. Toronto: University of Toronto Press, 1968. 16. Moseley SL, Hug I, Alim ARMA, So M, Samadpour-Motalebi M, Falkow S. Detection of enterotoxigenic. Escherichia coli by DNA colony hybridisation. J Infect Dis 1980; 142: 892-95. 17. Grunstein M, Hogness DS. Colony hybridisation: a method for the isolation of cloned DNAs that contain specific gene. Proc Natl Acad Sci USA; 72: 3961-65. 18. Mason PJ, Williams JG. Hybridisation in the analysis of recombinant DNA. In: Hames BD, Higgins SJ, eds. Nucleic add hybridisation: a practical approach. Oxford: IRL Press, 1985: 113-25. 19. Gennaro ML, Greenway PJ, Broadbent DA. The expression of biologically active cholera toxin in Escherichia coli. Nucleic Acids Res 1982; 10: 4883-90. 20. Lathe R, Hirth P, De Wilde M, Lecog JP. Cell free synthesis of enterotoxin of Esherichia coli from a cloned gene. Nature 1980; 284: 473-74. 21. De Wilde M, Ysebert M, Hartford M. DNA sequence of STa2 enterotoxin gene from an Escherichia coli strain of human origin. In: Levey SB, Clowes RC, Koenig EK, eds. Molecular biology, pathogenicity and ecology of bacterial plasmids. New York: Plenum Publishing Corporation, 1981: 596. 22. Feinberg AP, Vogelstein B. A technique for radiolabelling DNA restriction endonuclease fragments to high specific activity. Anal Biochem 1983; 132: 6-13. 23. Banigo EOI, Muller HG. Carboxylic acid patterns in ogi fermentation. J Sci Food Agric 1972; 23: 101-11. 24. Andah A, Muller HG. Studies on koko, a Ghanaian fermented maize porridge. Ghana J Agric Sci 1973; 6: 103-08. 25. Akinrele IA. Fermentation studies on maize during the preparation of traditional African starch-cake food. J Sci Food Agric 1970; 21: 619-25. 26. Muller HG. Traditional cereal processing in Nigeria and Ghana. Ghana J Agric Sci 1970; 3: 187-95. Transient release of lipid peroxides after coronary artery balloon angioplasty Free radical production may cause myocardial damage during reperfusion of ischaemic myocardial tissue; when free radicals interact with polyunsaturated fatty acids or their esters, lipid peroxides are produced. A product of lipid peroxidation, malondialdehyde, was measured in 10 subjects with stable angina who underwent angioplasty of a proximal high-grade stenosis (over 90%) of the left anterior descending coronary artery. In all subjects the duration of balloon occlusion was 60 s. Blood was withdrawn from the great cardiac vein immediately before balloon inflation (T0), immediately after balloon deflation (T60), 15 s after balloon deflation (T75), and 1 min after balloon deflation (T120). There was a significant increase in malondialdehyde at T60 compared with T0 for the first balloon inflation (mean increase 0·3 µmol/l [95% confidence limits 0·1, 0·5]), and at both T60 (0·31 µmol/l [0·15, 0·47]) and T75 (0·22 µmol/l [0·04. 0·40]) for the second balloon inflation. This model could be used to assess antioxidant effects of drugs. Introduction Oxygen-derived free radicals are produced after reperfusion of ischaemic myocardium in animals. Radicals have been directly detected by electron spin resonance,2 and free- radical damage products have also been measured. 3 Myocardial reperfusion is associated with several potentially harmful effects, including transient impairment of myocardial function (myocardial "stunning"),4 an increased incidence of dysrhythmias,5 5 and possibly increased myocardial necrosis.6 These adverse effects can be reduced by treatment with various antioxidants at the time of myocardial reperfusion,’,8 which indicates that free-radical formation is an important factor in their pathophysiology. ADDRESSES: Regional Medical Cardiology Centre, Royal Victoria Hospital, Belfast (M. J. D. Roberts, MRCP, T. G. Trouton, MD, M. M. Khan, FRCP, S. W. Webb, MD, C M. Wilson, MD, G. C. Patterson, MD, A. A. J. Adgey, MD); and Department of Chemical Pathology, Queen’s University, Belfast, UK (I. S. Young, MRCP, E. R. Trimble, MD). Correspondence to Dr A. A. J. Adgey, Regional Medical Cardiology Centre, Royal Victoria Hospital, Belfast BT12 6BA, UK.