Objectives: To display theorical and methodological basis of the molecular biology. To point out its main medical applications. Data sources: For this review, we analysed the English and French literature concerning the research and clinical aspects of the molecular biology, especially in anaesthesiology and intensive care, using the Medline(R) database. The current textbooks were also used. Study selection: We selected: 1) the original articles corresponding to the main advances that resulted in the present state of this discipline; 2) the reviews; 3) some chapters of textbooks. Data extraction: In this review, we report: 1) the current knowledge concerning the conservation and the expression of the genome; 2) the principles of the most widely used experimental techniques; 3) the medical applications of this knowledge in anaesthesiology and intensive care; 4) the more recent developments of this research field. Data synthesis: Within medical biology, molecular biology essentially corresponds to the study of nucleic acids. In this review, the general principles governing the organization and expression of the genome are discussed. The expansion of molecular biology has been a consequence of the widespread use of enzymatic tools, of which bacterial restriction enzymes were the first. Numerous enzymes are now available, permitting DNA strands to be cut, linked, synthesized and sequenced. Several of the most representative molecular biology techniques are described. Some of them, such as PCR, are commonly used in clinical situations. Animal experimental models have also been generated by genome altering methods, in order to analyse the phenotypic consequences of these modifications. Recently, a viable mammal, deriving from a differenciated cell, has been cloned. Human embryonic totipotent stem cells are now available in cultures. These advances have important ethical implications whilst, at the same time, offering new opportunities far medical applications. The state of gene therapy and human genome sequencing programmes is discussed. (C) 1999 Elsevier, Paris.
