Oxygen Radicals In Biology And Medicine

This book is based on the papers presented at the "Fourth International Congress on Oxygen Radicals (4-ICOR)," held June 27 - July 3, 1987, at the University of California, La Jolla. The chapters deal with the phenomena associated with highly reactive oxygen species (hydroxy, peroxy, alkoxy, aroxy, and superoxide radicals, as well as singlet oxygen) and their peroxidation products (hydrogen peroxide, hydroperoxides, peroxides, and epoxides) as they relate to the fields of chemistry, food technology, nutrition, biology, pharmacology, and medicine. The kinetics, energetics, and mechanistic aspects of the reactions of these species and the interrelationship of oxygen radicals (or any other free radicals) and peroxidized products have been emphasized. Special attention is focused on the mechanisms of the generation of free radicals and peroxy products in biosystems and on the adverse effects of these radicals and products in humans. The topics span the continuum from the simple chemistry of model systems to the complex considerations of clinical medicine. The book also explores the mechanisms of agents that protect against free radicals and peroxy products in vitro and in vivo. These agents include antioxidants used in materials, food antioxidants, physiological antioxidants, and antioxienzymes (SOD, glutathione peroxidase, and catalases). The use of these inhibitors to prevent damage to organs being prepared for transplantation, thereby maintaining the quality of transplanted organs and/or extending their "shelf-life," also is examined.

"This latest edition has been comprehensively rewritten and updated (over 80% of the text is new), whilst maintaining the clarity of its predecessor. There is expanded coverage of isoprostanes and related compounds, mechanisms of oxidative damage to DNA and proteins (and the repair of such damage), the free radical theory of ageing and the roles played by reactive species in signal transduction, cell death, human reproduction, and other important biological events. Greater emphasis has also been placed on the methods available to measure reactive species and oxidative damage (and their potential pitfalls), as well as the importance of antioxidants in the human diet." "This book is recommended as a comprehensive introduction to the field for students, clinicians and researchers, and an invaluable companion to all those interested in the role of free radicals in the life and medical sciences."--BOOK JACKET.

A NATO Advanced Study Institute on "Oxygen Radicals in Biological Systems: Recent Progress and New Methods of Study" was held in Braga, Portugal between Sep tember 1 and September 14, 1985, in order to consider the basic chemistry and biochem istry of activated oxygen (both radical and non-radical species) and their effect in biolog ical systems. This book summarizes the main lectures given at this meeting. While there is no attempt to cover all the major topics in the expanding subject of oxidative mechanisms in biology, an effort has been made to provide overviews on some key aspects of this field. The authors have attempted to convey a clear picture of both what is known and what remains unclear in their respective subjects. Not only are some of the techniques used for detecting activated oxygen species described, but also their strengths and limi tations. The chemistry of many of these species is discussed and the biological and/or pathological implications are carefully reviewed. The medical and therapeutic aspects of some of the well established pathways of damage and protection are analyzed. It is our hope that the material included in this book might be useful for both researchers and teachers at the graduate level. The success of this meeting was to a large extent due to the tireless committment of Professor Alberto Amaral and Dr. Concei~a:o Rangel; without their outstanding efforts in dealing with all the aspects of the organization, this summer school would not have been possible.

Free Radicals in Biology and Medicine has become a classic text in the field of free radical and antioxidant research. Now in its fifth edition, the book has been comprehensively rewritten and updated whilst maintaining the clarity of its predecessors. Two new chapters discuss 'in vivo' and 'dietary' antioxidants, the first emphasising the role of peroxiredoxins and integrated defence mechanisms which allow useful roles for ROS, and the second containing new information on the role of fruits, vegetables, and vitamins in health and disease. This new edition also contains expanded coverage of the mechanisms of oxidative damage to lipids, DNA, and proteins (and the repair of such damage), and the roles played by reactive species in signal transduction, cell survival, death, human reproduction, defence mechanisms of animals and plants against pathogens, and other important biological events. The methodologies available to measure reactive species and oxidative damage (and their potential pitfalls) have been fully updated, as have the topics of phagocyte ROS production, NADPH oxidase enzymes, and toxicology. There is a detailed and critical evaluation of the role of free radicals and other reactive species in human diseases, especially cancer, cardiovascular, chronic inflammatory and neurodegenerative diseases. New aspects of ageing are discussed in the context of the free radical theory of ageing. This book is recommended as a comprehensive introduction to the field for students, educators, clinicians, and researchers. It will also be an invaluable companion to all those interested in the role of free radicals in the life and biomedical sciences.

Excited states and free radicals are involved in the normal physiology of living systems, in pathological processes (including lipid peroxidation, inflammation, Parkinson's disease, cancer, and aging), in the mechanisms of drug action, and in the photochemotherapies such as the PUVA therapy for skin diseases and PDT for cancer. This text introduces the reader to this rapidly expanding field, one that lies at the borderlines of physics, chemistry, biology, pharmacology, and medicine. The authors explore in particular how time-resolved spectroscopic methods have found solutions at the molecular level to biological and medical problems. Topics include the nature of excited states and free radicals and the techniques for their study, activated oxygen species, DNA, proteins, carotenoids and photosynthetic reaction centers, photodermatology and melanogenesis, and aspects of cancer related to radio-, chemo-, and photodynamic therapy. Researchers and graduate students in photochemistry, photobiology, photomedicine, radiation chemistry and biology, and cancer therapies will find this book to be of very significant interest.

Although free radicals perform some useful immune functions, they can also damage healthy cells through a process called oxidation. Antioxidants reduce the effect of free radicals by binding together with these harmful molecules, decreasing their destructive power. This book highlights various issues of free radical biology from the perspective of antioxidant defense mechanisms. It also provides useful information on gene modulation, radiation-generated reactive oxygen species-induced apoptosis in cancer, and environmental aspects associated with free radicals’ exposure on living systems.

The rapid expansion of the area of free radical biology in the last 25 years has occurred within a framework of assumptions and preconceived notions that has at times directed the course of this movement. The most dominant of these notions has been the view that free radical production is without exception a bad thing, and that the more efficient our elimination of these toxic substances, the better off we will be. The very important observation by Bernard Babior and colleagues in 1973 that activated phagocytes produce superoxide in order to kill micro organisms, served to illustrate that constructive roles are possible for free radicals. For many in the field, however, this merely underscored the deadly nature of oxygen-derived radicals, both from the microbe's point of view and from the host's as well. (Phagocyte-produced superoxide is responsible in part for the tissue injury manifested as inflammation. See Harris and Granger, Chapter 5, and Leff, Hybertson and Repine, Chapter 6.) Mother Nature, however, has a penchant for being able to make a silk purse from a sow's ear. If one is dealt a bad hand, one must simply make the best of it. After two decades of focusing on the destructive side of free radicals, the last few years have begun to reveal a new and finer perspective on free radical metabolism - a role in regulation of cellular function (see Schulze-Osthoff and Baeuerle, Chapter 2). Evidence from a number of sources suggests that an increase in the oxidative status of cell encourages that cell to grow and divide. Increasing the expression of mangnese superoxide dismutase can suppress the malignant phenotype of melanon cells (see Oberley and Oberley, Chapter 3). Oxidative stress beyond a certain poitosis (from the Greek, literally "to fall apart"). Is this suicide response an evolutionary fail-safe device to curtail tumorogenesis? Does oxidative stress-induced apoptosis account for the loss of immune cells in AIDS (see Flores and McCor Chapter 4)? This volume attempts to present the spectrum of roles, both good and bad played by active oxygen species as understood at this point in the evolution of this field of free radical biology.