Molecular gastroenterology--implications for medical practice.

Molecular biology has revolutionized our understanding of the life of the cell. The development of concepts has been accompanied by the development of new technologies, many of which have clinical applicability. This new armamentarium includes methods for detection and amplification of minuscule amounts of DNA, automated methods for DNA and RNA sequencing, the ability to express a gene in cultured cells and harvest its product, approaches to identify genes whose product is unknown, methods for a detailed understanding of the regulation of gene expression, and innovative methods for gene therapy. These developments have already had an impact on gastroenterology, exemplified by the identification of hepatitis viruses and the agent causing Whipple's disease, development of a recombinant vaccine for hepatitis B, and isolation of the cystic fibrosis gene, which will lead to the diagnosis and treatment of this disease. This editorial outlines these recent changes in the conceptual and practical framework of gastroenterology.