The release of a coronary vasodilator metabolite from the guinea-pig isolated perfused heart stimulated by catecholamines, histamine and electrical pacing and by exposure to anoxia

The results of surveys and inquiries to identify autistic children, carried out in England and Wales, the U.S.A. and Denmark, are compared. Three studies, in each of which either a total population of children or a wide range of handicapped children was screened, using case-note inspection and interviews, all estimated the prevalence of the autistic syndrome to be between four and five children per 10,000 aged under 15 years. Inquiries that counted diagnosed cases only or that relied upon local authority records produced much lower prevalence rates for the autistic syndrome. The reasons for this are examined, and the implications for prevalence studies of handicapping conditions are discussed.