Although blood substitutes represent a goal that has been sought for more than a century, their development is now on the cutting edge of biotechnology: beyond biochemistry and molecular biology, these products are being integrated into the larger physiological picture of gas transport that is essential to every living organism. New products will find obvious clinical application, since they overcome many of the problems with blood transfusion, such as the need to crossmatch, storage limitations, and the risk of transmission of infectious disease. As work continues to bring this new class of products to market, discoveries have been made about very basic aspects of how red blood cells work with regard to the exchange of oxygen and carbon dioxide and interactions with molecules such as nitric oxide and carbon monoxide which may mediate contractility of smooth muscle. These new challenges are being met with impressive rapidity as products are readied for testing and introduction into clinical use. As more is understood about the general properties of artificial blood substitutes, attention is focusing on applications which will benefit the most from their availability. This volume is a collection of chapters by researchers currently working in the field of blood substitutes and closely related fields. Each of them focuses on current challenges from a different perspective, from the clinical question, "What is the target?", to detailed descriptions of the interactions with nitric oxide, endotoxin, and carbon dioxide. Included in the volume is a review of the peer-reviewed research published in 1995 and a general discussion of current products and potential clinical applications. Takentogether, these chapters provide an up-to-date picture of this rapidly evolving field.

This book is not a "proceedings" volume. Rather the chapters are essays by experts in the field of blood substitutes, invited by the editors to con tribute to the 1996 "Current Issues in Blood Substitutes Research and Development" course given in San Diego, March 18-21. The contributors were selected because of their expertise in areas deemed by the editors to be critical to the advancement of the field. The course, as in past years, is heavily influenced by feedback from par ticipants, and by research in this and related fields. In addition to the didactic lectures (for which these chapters are the foundation), the course also offers the opportunity for presentation of research reports, progress reports from the various companies currently commercializing products, and round table discussions of selected subjects. Thus, we are grateful to past participants for their helpful comments. Production of a book, especially on a short timeline, is not an easy feat."

This volume contains a collection of essays by selected authors who are active in the field of blood substitutes research or closely allied disciplines. These essays were delivered as lectures by the authors at the second annual "Current Issues in Blood Substitute Research and Development - 1995" course sponsored jointly by the Departments of Medicine and Bioengineer ing, University of California, San Diego, the National Institutes of Health (NHLBI), and the U.S. Army on March 30, 31, and April 1, 1995 in San Diego. This course had three goals: to present fundaniental discussions of scientific issues critical to further development of artificial oxygen carriers, to provide academicians a forum to discuss their current research, and to provide the companies involved in developing products the opportunity to update the audience on their progress. The organization owes much to the solicited comments of the attendees of the 1994 course. We would like especially to thank the U.S. Army, particularly through the efforts of COL John Hess, who provided significant funding to make publication of this volume possible. In addition, a number of the participating companies provided additional financial support to offset the costs of the course. These include Alliance Pharmaceutical Corp., Hemosol, Nippon Oil and Fat, Northfield Laboratories, and Ortho Biotech."