The children, he concluded, had excess phenylpyruvic acid in the urine, the condition which came to be called phenylketonuria (PKU).His careful analysis of the urine of the two affected siblings led him to request many physicians near Oslo to test the urine of other affected patients. This led to the discovery of the same substance he had found in eight other patients. He conducted tests and found reactions that gave rise to benzaldehyde and benzoic acid, which led him to conclude that the compound contained a benzene ring. Further testing showed the melting point to be the same as phenylpyruvic acid, which indicated that the substance was in the urine.In 1954, Horst Bickel, Evelyn Hickmans and John Gerrard published a paper that described how they created a diet that was low in phenylalanine and the patient recovered. Bickel, Gerrard and Hickmans were awarded the John Scott Medal in 1962 for their discovery.PKU was the first disorder to be routinely diagnosed through widespread newborn screening. Robert Guthrie introduced the newborn screening test for PKU in the early 1960s. With the knowledge that PKU could be detected before symptoms were evident, and treatment initiated, screening was quickly adopted around the world. Ireland was the first country to introduce a national screening programme in February 1966, Austria also started screening in 1966 and England in 1968.In 2017 the European Guidelines were published. They were called for by the patient organizations such as the European Society for Phenylketonuria and Allied Disorders Treated as Phenylketonuria. They have received some critical reception.
Water molecules freely diffuse through the plasma membrane in both directions, and as the rate of water diffusion is the same in each direction, the cell will neither gain nor lose water. == References ==