Biodegradable polymers as drug delivery systems

1257 The Genome, edited by RS Verma, VCH, 1990, pp XlX + 327, DM 136, £ 48 The book entitled "The Genome', written by Professor RS Verma, is the first volume of the "Frontiers in Molecular and Cellular Biology', a series of monographs which are edited by Professor E Bittar. It is an excellent textbook, well documented, well written and of great didactic value. Its only drawback is its title which is misleading because this book is essentially a monograph on "The Chromosome'. The range of topics covered can be divided into two parts: - T h e first part is the most important in size, the most original and certainly the most interesting. It summarizes what is known concerning the structure, behavior and organization of the vertebrate chromosomes. The anatomy of the chromosome is presented in Chapter 1. It is illustrated with several excellent drawings making this complex subject accessible to virtually everybody. Chapter 2 provides an overview of the recent advances in staining techniques that have made possible the development of cytogenetics over the last ten years. Chapter 3 is entirely devoted to heterochromatin and Chapter 4 to the biology of the centromere. Chapter 5 e~plains the behavior of the chromosome during the meiotic process and the ten pages devoted to the synaptonemai complexes represent probably the most original part of this monograph and its clarity is worth noting. Finally the last Chapter of the first part, Chapter 6, explains the role of the sex chromosomes in sex determination and the mechanisms of dosage compensation. - The second half of the book is composed of three chapters on some of the pathological aspects of cytogenetics: Sister chromatid exchanges, Aneuploidies and chromosomal rearrangements, and genomic diversity in neoplasia. These chapters are less original than the first six but it was not possible to write such a monograph skipping these aspects. - The last chapter of the book entitled 'The unfolding genome" could have been omitted. It describes the essential of gene mapping and sequencing, in a mere 20 pages, and its content duplicates that of many other textbooks. This book has been edited with much care, and for most of the chapters, the bibliography extends to 1989. Its originality, the excellent quality of the numerous illustrations and the alarity of the text justify its acquisition. JL Guenet

Biodegradable Polymers as Drug Delivery Systems, Drugs and the Pharmaceutical Sciences/45, edited by M Chasin, R Langer, Marcel Dekker, 1990, pp 368, $ 99.75 (US and Canada)/$119.50 (all other countries) This book dedicated to the biodegradable polymers is timely in view of the dramatic increase of the use of polyme[s in drug delivery systems over the past decade. The stated purpose of this multi-authored book is to examine one by one some selected polymers and to give information on their properties, synthesis and formulation. Each chapter is written by a leading specialist in his field. The style and approach to the different topics are variable: some chapters provide much more clear treatments with useful diagrams (generally chapters on synthetic polymers) while others are more unsatisfactory, and without any illustrations (eg 'Natural Polymers as Drug Delivery Systems'). The chap-

ters are well referenced (850 references) to facilitate further research. Analytical tools, while sometimes given, are more often lacking. The absence of a general introductive chapter with a general and comparative presentation of the different polymers makes this book difficult for a student new to the field. However, this book can be recommended because it gives a fairly comprehensive review of the biodegradable polymers. A Bayol

Yeast strain selection, edited by CJ Panchal, Marcel Dekker, 1990, pp 368, $ 125 (US and Canada)/$ 150 (all other countries) This volume reviews the various aspects of yeast mycology that are relevant to biotechnology. Most chapters are focused on Saccharomyces, by far the yeast genus the most frequently found in industrial processes and the most extensively studied in laboratories. Recent developments in yeast molecular genetics have found a direct application in the construction of S cerevisiae lab strains that produce high le~'els of commercialy-valuable proteins. Foreign genes have also been expressed in industrial strains of Saccharomyces, essentially brewing strains (S cerevisiae and S carlsbergensis), in order to facilitate the fermentation process. However, whereas some recombinant lab strains are already being used for the production of vaccine or pharmaceutical products, genetically-engineered beer strains are generally not being used in industrial processes for reasons not necessarily scientific or technological but rather lbr complex regulatory considerations. Another consequence of the great advances in the field of yeast molecular genetics is to afford new tools for the study and improvement of nonconventionnal yeast species. Thus r embers of various economically-important yeast genera, for which no sexual cycle is known, and for which genetic manipulation was restricted to doubtful attempts of spheroplast fusions, can now be transformed by clo~ed DNA. As a result, strategies involving gene replacement, gene disruption or precise by site-specific directed mutation can now be envisaged. A special chapter deals with these 'non-saccharomyces' yeast strains which are gaining increasing importance in industrial microbiology. This book includes a new summary or recent references which will be very helpful not only for newcomers in this rapidly-evolving field but also for trained yeast biotechnologists. They will have a precise overview of the modern tools ~that are available for yeast strain improvement as well as of the recent strategies that have been successfully developped for this purpose. O Loison

Methods in Biochemical Analysis, volume 35, Protein structure determination, edited by H Suelter. Interscience, John Wiley and Sons, 1991 The Editor planned this volume to be a compilation of chapters which could be used as a textbook in a course on protein strut-