Mammalian fucosidases. 1. The synthesis of substrates and inhibitors.

of radioautographic techniques (Logan, Ficq & Errera, 1959). This permits the study of incorporation experiments in individual nuclei but does not give any information about the quantitative chemical changes in the nuclei. It is of interest to know whether there are any common biochemical changes in the nuclei as a result of feeding the two carcinogens. However, the two types of nuclear preparations behaved differently in the incorporation of labelled precursors into nucleic acids and proteins, even though both groups of nuclei, however, showed increases in their protein, nucleic acid and phospholipid content. Thus, although a reasonable correlation is obtained between the biochemical and histological changes in the two groups, there is so far little evidence of any common pattern in the nuclear changes. It is therefore necessary to study more hepatocarcinogens and to compare them with compounds which produce non-malignant hyperplasia of liver and bile-duct cells.