Unfinished business

The past 40 years have witnessed the development to maturity of molecular biology from its beginnings and determined attempts to apply this discipline in medicine, particularly to genetics, haematology, immunology and cancer research. However, although we have accumulated a detailed understanding of the genetic code and the mechanisms of the central dogma of molecular biology and have developed exquisitely sensitive and precise technologies, most recently represented by DNA recombinant techniques, many of the fundamental biological problems of 40 years ago still remain unsolved today. Some of these are listed and discussed.

Theoretical molecular biology: prospectives and perspectives

I briefly discuss some aspects of theoretical molecular biology. Specifically, I include the issues of searches for homologies via string matchings, for patterns of specific nucleotide groupings and of sequence-structure relationship. The various approaches developed in order to achieve this end are described, attempting to convey some of the excitement in this quickly growing field.

On the advent and necessity of molecular biology in the clinical management of lung cancer

The very rapidly expanding knowledge and technologies of molecular biology are reviewed with special reference to problems in the clinical management of lung cancer. Genetic events, tumor-associated antigens, production of murine and human monoclonal antibodies, culture of cell lines, intratumoral phenotypic diversity and squamous-lung-cancer-associated antigens are discussed and related to possible therapeutical approaches. A monoclonal antibody with high specificity for squamous cell lung cancer reacted positively in blood samples and tissue extracts in about 80%. Its use as a marker during follow-up after surgical treatment is demonstrated by examples. It is concluded that there will be limiting factors in the therapeutic use of monoclonal antibodies, such as intratumoral phenotypic diversity. Genetic analysis might be a method for selecting a high risk group of individuals in whom exposure to carcinogenic factors, such as cigarette smoking, would be fatal. Murine monoclonal antibodies can be used in vitro for screening, for histological examination and for prognostic studies. Human monoclonal antibodies should be used for in vivo purposes as well as for the screening of primary tumor and metastases for the therapy. To achieve usable results, the monoclonal antibodies should be raised against the cell membranes that, in particular, are expressed on the stem cells of the neoplastic cell population.

New insights into receptor regulation

This review provides a brief summary of certain recent advances in our understanding of receptor regulation, signal transduction, and the diverse pathways by which receptor-ligand complexes are internalized and delivered to specific organelles, together with recycling of receptors back to the cell surface. Emphasis is also given to the importance of methodological advances in receptor isolation, immunologic analysis of receptor structure and function, the development of new instrumentation for microchemical characterization of very small amounts of receptor material, and the increasing use of genetic engineering techniques to isolate the genes for receptors and their regulatory subunits, to transfer such genes between cells, and to study receptor function by creating structurally modified receptors via subtle changes in gene structure.

Intelligent computational assistance for experiment design

We have developed an automated system for the design of laboratory experiments in molecular biology. The system uses a planning method known as skeletal plan refinement that attempts to emulate the human cognitive task of experiment design. This paper describes the theory, history, and implementation of the design system and illustrates its function in the domain of DNA cloning experiments.

The challenge of new clinical developments

Developments arising from new discoveries already made and new technologies already developed will pose great challenges en route to the year 2000. Given the accelerating rate of change it is likely that new discoveries not yet contemplated will present even greater problems not just to the health professions but to the community and to our governments. The difficulties will lie equally in the clinical area and in social, financial, and ethical domains. One example which is worth addressing arises from the discovery of DNA which has led to new technologies with major implications in all these areas today, and a second one arises from the transformation in the care and survival of newborn babies.

Protein engineering

The prospects for protein engineering, including the roles of x-ray crystallography, chemical synthesis of DNA, and computer modelling of protein structure and folding, are discussed. It is now possible to attempt to modify many different properties of proteins by combining information on crystal structure and protein chemistry with artificial gene synthesis. Such techniques offer the potential for altering protein structure and function in ways not possible by any other method.

Reduction and genetics

Examples of reduction outside of physics typically concern in principle possibilities; e.g., if we had a decent psychological theory of human behavior, we could reduce it to neurophysiology once we know more. However, in one instance, a reduction is actually well underway - the reduction of Mendelian genetics to molecular biology. Empirical and conceptual difficulties in setting out this reduction have led certain philosophers to modify the traditional logical empiricist analysis of theory reduction, first, to allow for necessary corrections and, second, to introduce a temporal dimension [reduction, genetics, theory, logical empiricism].

New medicine and new biology

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Frontiers of the biological sciences

The history of the molecular revolution in biology is described, emphasizing its dependence on the emergence of bacterial genetics, the fusion of genetics and biochemistry, and the development of greatly improved techniques for studying macromolecules. Central concepts have included molecular information transfer, both by nucleic acids and by allosteric proteins; the spontaneous conversion of one-dimensional information into three-dimensional structures; and the extraordinary unity in the molecular mechanisms underlying the rich diversity of biology. The merging of molecular and morphological studies, to yield the very broad field of cell biology, is described more briefly, as are also some present frontiers in several areas of biology that present challenges at other levels of organization.