Numerous studies have proven the biological basis of memory formation and have begun to identify the biochemical traces and cellular circuits that are formed by experience, and which participate int the storage of information in the brain, its retention for long durations, and its retrieval upon demand. Cells in the nervous system have the capability of undergoing extremely long-lasting alterations in response to hormonal, pharmacological, and environmental stimulations. The mechanisms underlying this neuronal plasticity are activated by experiential inputs and operate in the process of learning and the formation of memories in the brain. This volume presents research areas which have not been highlighted in the past. In addition to studies on the involement of functional proteins in neuronal adaptation, this volume presents recent developments on the critical roles of bioactive lipids and nucleotides in these processes. In addition to the widely studied role of second messengers, a review of studies on extracellular phosphorylation systems operating on the surface of brain neurons is presented.The first section of the volume presents studies of basic mechanisms operating in a wide range of adaptive processes. The second section presents recent advances in investigations that have demonstrated the clinical implications of this research. These include: state of the art use of transgenic models in studies of molecular and cellular mechanisms implicated in familial Alzheimer's disease and Amyotrophic Lateral Sclerosis; studies of specific proteins implicated in Alzheimer's disease, including an adapter that binds to the beta-amyloid precurser protein (beta-APP) and the microtubular protein Tau and its membrane-bound counterpart. The advantages of using cell culture models for elucidating the causes of neuronal degeneration and for identifying mechanisms of neuroprotection are also presented among the chapters in the section on clinical implications.

Hypoxia is a constant threat throughout life. International experts from many different fields, including clinicians, clinical researchers, and basic scientists, have contributed to this volume, presenting state-of-the-art information regarding normal and abnormal (pathophysiological) responses to hypoxia. The topics covered include visitors to high altitude, the latest developments on high-altitude cerebral and pulmonary edema, the brain in hypoxia, high-altitude headache, and similarities between ischemic and hypoxic injury to the brain. In addition topics are covered such as blood-brain barrier in hypoxia, hypoxia interactions with vascular growth, and how humans adjust to extreme hypoxia.

The overall scope of this new series will be to evolve an understanding of the genetic basis of (1) how early mesoderm commits to cells of a heart lineage that progressively and irreversibly assemble into a segmented, primary heart tube that can be remodeled into a four-chambered organ, and (2) how blood vessels are derived and assembled both in the heart and in the body. Our central aim is to establish a four-dimensional, spatiotemporal foundation for the heart and blood vessels that can be genetically dissected for function and mechanism. Since Robert DeHaan's seminal chapter "Morphogenesis of the Vertebrate Heart" published in Organogenesis (Holt Rinehart & Winston, NY) in 1965, there have been surprisingly few books devoted to the subject of cardiovascular morpho genesis, despite the enormous growth of interest that occurred nationally and inter nationally. Most writings on the subject have been scholarly compilations of the proceedings of major national or international symposia or multi authored volumes, without a specific theme. What is missing are the unifying concepts that can often make sense out of a burgeoning database of facts. The Editorial Board of this new series believes the time has come for a book series dedicated to cardiovascular mor not only as an important archival and didactic reference phogenesis that will serve source for those who have recently come into the field but also as a guide to the evo lution of a field that is clearly coming of age.

Recently, attention has been called to the role that microvascular organization plays in the functional morphology of all organs and tissues, both in normal and pathological conditions. Since its development by Murakami, the corrosion cast method for scanning electron microscopy has come to be considered one of the most efficient means in clarifying the three-dimensional features of the microcirculation of organs and tissues. Scanning Electron Microscopy of Vascular Casts: Methods and Applications was planned to supply fundamental and new information regarding microcirculation studies to general biologists, anatomists, pathologists and clinicians. The contributions to this volume, contain original findings and excellent electron micrographs obtained by using recently improved corrosion cast methods. The rich variety of papers in this book will be useful to many, and will provide both the basic and clinically oriented readers with good ideas, suggestions, and original and worthwhile information.

If one were to design the ideal nuisance for cell cultures, the resultant might well be similar to mycoplasmas. These micro organisms are very prevalent in nature, being found in the oral cavity, blood, the mucous membranes of the respiratory and uro genital tract and other tissues of both man and animals. They are relatively difficult to detect microbiologically and chemically. Lacking cell walls, they do not routinely produce turbidity in cell cultures and are resistant to antibiotics that act on cell walls. Mycoplasmas grow to high titers in cell cultures. Concen 7 8 trations of 10-10 colony forming units per ml of supernatant medium are representative. Additionally, more numbers are attached to cell membranes. Further, mycoplasmas have been shown to mimic in vitro effects of viruses and toxic chemicals. In various cell culture systems, mycoplasmas have been known to cause cell death, decrease or increase cell growth, affect virus tite s, induce interferon, cause chromosome damage, induce transformation, cyto pathic effects, alter phenotypic expression, and significantly alter metabolic pathways and products of cells. The presence of such high concentrations of mycoplasmas in cell cultures constitutes a true in vitro infection. Such infected cell cultures, with a 8 9 total of 10 _10 or more actively metabolizing mycoplasmas, have no place in controlled, standardized cell culture procedures. Numerous reports have been published on mycoplasma assay pro cedures, effects of infection, and preventive and elimination measures."

Heme oxygenase is rapidly taking its place as the centerpiece of multiple inter acting metabolic systems. Only 25 years ago heme oxygenase and its metabolic prod ucts appeared to be merely a simple metabolic system-one substrate, heme; one enzyme, heme oxygenase; and one set of products, iron to be recycled, and bilirubin and carbon monoxide to be disposed. From a group of about 25 people in 1974, as judged by attendance at various Gordon conferences, heme oxygenase has, in the year 2000, attracted working scientists-and clinicians I might add-by the hundreds and has produced referenced publications by the thousands. It is well-deserved attention. Heme oxygenase system is now similar to the metabolic networks surrounding glucose in those complex maps of glycolytic and non-glycolytic metabolic pathways, which we had to memorize as students. The relevance of heme oxygenase to regulatory biology was recognized many years ago, but the work conducted over the past five years has created a new wave of emphasis focusing on genetic manipulation to alter heme oxygenase gene expression, the regulatory actions of heme oxygenase products including carbon monoxide, and the significance of changes in the heme oxygenase system. The physiological and pathological relevance of heme oxygenase in the brain, heart, liver, bone marrow, organ transplant, lung and kidney, opens many areas of investigation in various dis ciplines. Advances in the pharmacology of bilirubin and its ability as an antioxidant have provided a new avenue in clinical research.

We have considered it to be a demanding assignment to provide a complete exposition dealing with the nature of radiation, its effects, and protection against it to workers in health-related activities. "Radiation" (and more precisely "ionizing radiation") is emitted by X-ray machines, nuclear reactors, and nuclear weapons, but also comes from natural sources to which we are all exposed. It would have been easier to deal with this subject area with the terminology and mathematics employed by specialists. However, although most of the potential readers probably have obtained further pertinent knowledge, we assume no more than a high school education in science and mathematics and the challenge was to provide maximum information within this constraint. This book contains five sections: (A) Radiation Physics, (B) Radiological Physics, (C) Radiation Biology, (D) Radiation Effects on Human Populations, and (E) Radiation Protection. Each section is preceded by a synopsis covering its essential features. It provides sufficient information to enable readers to obtain a general under standing of the subject of the section and an adequate background for comprehension of other sections. The more detailed presentation in the bulk of each section is followed by appendixes that generally contain more advanced topics. This scheme necessarily involves some repetition but permits a more flexible approach for readers who are especially interested in the contents of particular sections.

The 'Formation of the Heart and its Regulation' reviews in considerable detail the major events in heart development and their control via genes, cell-cell interactions, growth factors and other contributing elements. In addition, there is an extensive and useful overview of the field of heart development taken as a whole. The book will appeal to all students and researchers working on cardiovascular development and to pediatric cardiologists.

Over the last twenty-five years, there has been an extensive effort, still growing for that matter, to explore and understand the organization of extrastriate cor tex in primates. We now recognize that most of caudal neocortex is visual in some sense and that this large visual region includes many distinct areas. Some of these areas have been well defined, and connections, neural properties, and the functional consequences of deactivations have been studied. More recently, non invasive imaging of cortical activity patterns during visual tasks has led to an expanding stream of papers on extrastriate visual cortex of humans, and results have been related to theories of visual cortex organization that have emerged from research on monkeys. Against this backdrop, the time seems ripe for a review of progress and a glance at the future. One caveat important to emphasize at the very onset is that the reader may be puzzled or confused by the use of different terminologies. Individual investi gators commonly tend to favor different terminologies, but in general some prove more advantageous than others. As discussed by Rowe and Stone (1977) as well as by others, there is an unfortunate tendency for role-indicating names to lead to fixed ideas about function, in contrast to those that are more neutral and adaptable to new findings.

New interest in light microscopy of the last few years has not been backed up by adequate general literature. This book intends to fill the gap between specialized texts on detailed topics and general introductory booklets, mostly dealing with the use of the conventional light microscope only. In this short textbook both new developments in microscopy and basic facts of image formation will be treated, including often neglected topics such as axial resolving power, lens construction, photomicrography and correct use of phase-en interference contrast systems. Theoretical background will be dealt with as far as necessary for a well-considered application of these techniques enabling a deliberate choice for the approach of a certain problem. Over 150 illustrations (photomicrographs and diagrams) complete the information on microscopy of the nineties in the biomedical field, intended for scientists, doctors, technicians and research students. Many drawings have been contributed by the illustrator R. Kreuger; the photographic work has been executed by J. Peeterse. Secretarial assistance in preparing the manuscript was given by Ms T. M. S. Pierik. Dr M. J. Pearson has corrected the English of the final text.

Who said learning A&P can't be fun? The Anatomy and Physiology Learning System, 4th Edition makes it easy to learn normal structure and function of the body, and summarizes the common disorders found in each body system. Written by well-known educator Edith Applegate, this book combines clear, crisp writing with hundreds of vibrant illustrations. This edition includes a stronger emphasis on medical vocabulary, so you understand key terms before you learn anatomy. A wide array of engaging features simplifies physiology concepts, and an Evolve website supports the book with a wealth of new learning opportunities. Even if you have little or no background in science, you will learn the A&P you need to enter your career! A clear and concise writing style makes the book easy to read and understand, even if you have a limited background in science. Quick Check questions let you check your comprehension at various points within a chapter. Chapter quizzes provide recall, thought, and application questions to check your understanding of A&P concepts. An Evolve website includes online tutoring, a Body Spectrum coloring book, Anatomy & Physiology Pioneers boxes with brief biographies of trailblazers in science and medicine, 3-D animations, an audio glossary, Spanish pronunciations of key terms, and frequently asked questions. Outlines and objectives at the beginning of each chapter help you prioritize your study. Key terms are highlighted to help you analyze, pronounce, and spell important medical words. A glossary provides definitions and a pronunciation guide for key terms. Functional Relationships pages illustrate the connection between each individual system and the other body systems, showing how all systems work together. Representative Disorders describe the common health issues associated with each body system. Focus on Aging boxes describe the effects of aging on body systems. Quick Applications boxes connect the material to real-world scenarios. From the Pharmacy boxes describe common medications for each body system and include a brief description of the drug and its action, common uses, and abbreviations. 100 new high-quality illustrations help you visualize anatomical features and physiological processes. Chapter summaries and vocabulary quizzes have been added to the end of each chapter. New Building Your Medical Vocabulary section covers the history of medical words, giving you the building blocks to use and recognize new terms.

Lymphatic mapping techniques have proven to be useful to the early detection and safe treatment of endometrial and cervical cancers; however, the techniques have much of value to offer for breast cancer also and particularly for vulvar cancer, where there has been an explosion of interest and research. In the new edition of Clinical Lymphatic Mapping of Gynecologic Cancers, the techniques are fully explained, with consideration of the latest developments and technologies.

The NATO Advanced Study Institute on "Cellular and Molecular Control of Direct Cell Interactions in Developing System" has been attended by 15 invited main lecturers and 60 participants. According to its purpose senior scientists, postdoctoral trainees and graduate students working in areas like biology, biochemistry, electrophysiology, medicine etc . . . could discuss their common interest in the various structural, ultrastructural, molecular and functional aspects of cell interactions in developing in vivo and in vitro systems. Whereas the topics of the first week have been mostly concerned with the general aspects of cell interactions in embryogenesis (section I and II of this book), the second week has been mainly devoted to the structures and functions of the direct cell contact sites at the membrane level as gap junctions, including electrophysiological aspects, dye coupling and selective cell-cooperation in some model systems as the neuro-muscular junctions (section III-V of this book). A multidisciplinary and stepwise approach, from initial cell contacts in early embryogenesis up to well defined selective cell cooperation, appeared to be an efficient means to provide answers to the question of how cells control, in a dynamic system as given in a differentiating embryo, their multiple temporary and permanent interactions so necessary for ordered cell positioning, cell linking and well established cell-to-cell communication.

During October 18-31, 1980, the first course of the Inter- national School of Pure and Applied Biostructure, a NATO Advanced Study Institute was held at the "Et tore Majorana Center for Scien- tific Culture" in Erice, Sicily, co-sponsored by national and international agencies. The subject of the course was "Cell Growth", with participants (from 16 different countries) selected worldwide. The study of cell growth has been one of humanity's most challenging problems and it has been approached from many differ- ent points of view, such as biochemistry, genetic engineering, cell biology, zoology, oncology, immunology, biophysics and a few other fields. It has been very difficult to keep such varied points of view all in one room and in one audience, because of the heterogeneity of background and inherent difficulty of communica- tion, with occasional nominalistic rather than factual debates. This Institute aimed to bypass those limitations by approaching in a structured and tutorial fashion the problem of cell growth in three dimensions: (1) in terms of the various disciplines involv- ed, from molecular to cellular biology, from genetic engineering to clinical oncology, from biophysics to immunology; (2) in terms of the system studied, from prokaryotes to eukaryotes and cancer cells; (3) in terms of the various levels of macromolecular orga- nization, from membrane to cytoskeleton and chromatin.

This volume documents the proceedings of a symposium on "Lung in its Environment" held at the Ettore Majorana 'Center for Scientific Culture, in Erice, Sicily, between 16th June and 21st June 1980. This was attended by about 200 participants drawn from Europe as a whole, but the majority were from Southern Europe. The discussion was recorded either in English or Italian and the tapes were reduced to a verbatim typescript by the Ente Nazionale Interpreti Congresso. The verbatim typescript has been edited using a few guiding principles as follows: - 1. Titles and honorifics have been eliminated unless the statement is addressed to a specific person. 2. The style of the speakers in the discussion has been preserved as far as possible and not reduced to a strictly grammatical format. 3. Where references to illustrations (e.g., on the blackboard) are made, the comments have been left unaltered and many are understandable. Removing them detracted from the sense. 4. The air of informality in the proceedings has been preserved so far as possible. 5. The responsibility for the discussion rests solely with the editors, and no contributor has had the opportunity of correcting what he said. 6. No manuscript was received from two participants, but the discussion of their presentations has been included since it contains some points of substance. 7.

Advances in Cell Biology has been initiated as a continuing, multi-volume series to report on the progress of a wide spectrum of problems of cell structure and cell func tion. In arranging these volumes individual contributors are asked not only to review the major new information, but especially to present the state of a given problem or area by discussing the current central issues, speculations, concepts, hypotheses, and technical problems. We intend, in addition, that these volumes will not be concerned with comprehensive reviews of the recent literature but will consist rather of presenta tions of an interpretative and integrative nature, based on selection of major research advances. It is our aim that these volumes should provide the means whereby cell biologists may keep themselves reasonably well informed about the current progress in research areas in cell biology in which they are not immediately or directly involved themselves. The articles, nevertheless, are expected to bring into focus the experimental objectives of the specialists in a given research area. D.M.P. L. G. E. M. vii Contents v Contributors Preface vii Bacterial Chromosome Replication 3 I. Peter L. Kuempel 57 2. Structure and Replication of Eukaryotic Chromosomes David M. Prescott Ultrastructure and Interaction of the Kinetochore and Centriole 3.

Many factors may influence the release of neurotransmitters from airway nerves 1]. This is likely to be important in physiological control of airway functions and may be particularly relevant in airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Neural elements in airways interact in a complex manner and the activation of certain neural pathways may profoundly influence the release of transmitters from other neural pathways. Similarly inflamma tory mediators released from inflammatory cells in the airways may also modulate neurotransmitter release. There are marked differences be tween species in airway innervation and in neuromodulatory effects and, wherever possible, studies in human airways have been emphasised, although information on neuromodulation in human airways is some what limited at present. Release of neurotransmitters from nerve terminals occurs via a Ca2+ dependent secretion evoked by a nerve action potential, but may also be evoked experimentally by a high extracellular K + concentration which directly depolarises the nerve terminal membrane. Modulation refers to the alteration of neurotransmitter release, which may either be increased (facilitation) or reduced (inhibition) by the action of a particular agent, thus changing the magnitude of the neurally-mediated response. Such agents would normally act on receptors on the nerve terminal which are referred to as pre-junctional (or presynaptic) receptors, in contrast to post-junctional (or post-synaptic) receptors located on the target cells which are influenced by that particular transmitter."

The brine shrimp Artemia has become an important experimental system for studies of the developmental process. In recent years the shrimp has yielded considerable information on the pattern of development, bio chemistry, and gene structure and expression of crustaceans. This book is a compilation of research activity from twenty five of the most active re search laboratories working with brine shrimp in the above areas. It also represents the proceedings of a NATO Advanced Research Workshop held in Montreal, Canada, August 11-13, 1988. The book contains twenty nine full papers covering the major areas discussed at the workshop. In addition, one page abstracts representing seventeen poster presentations which were given at the workshop, and which were deemed to be most relevant to the theme of the book, are included. These are designated with an al in the Table of Contents following the title of each paper. A considerable amount of discussion which took place during the workshop has not been included in the book because of space limitations. However, the editors will endeavour to make some of this in formation available at a later date through the Artemia Newsletter. In addition to the high percentage of invited speakers who attended and contributed to the workshop, the organizers would like to thank a number of participants who made valuable contributions to the major dis cussion sessions. These include: John Freeman, Michael Horst, Herman Slegers, Jack Vaughn, Frank Conte, Sandy McLennan, Clive Trotman and Patrick Sorgeloos."

This volume of Molecular Biology of Hematopoiesis is dedicated to many inter national scientists and clinicians for their contribution to the field of Hematology/ Oncology presented at the 11th International Symposium on Molecular Biology of Hematopoiesis, which was held in Bormio, Italy, June 25-29, 1998. The continuous support of the Presidents of the meeting, Professor F. Takaku, President of Jichi University, and E. D. Thomas, Nobel Laureate, was greatly acknowledged, especially Professor Takaku, for his vision and support for development of gene therapy in Japan. New information on BMT for autoimmune disease and organ transplantation was presented at the symposium and is published in this volume. Several new findings on gene therapy/transfer into HSC were presented by E. F. Vanin and A. Nienhuis, K. Humphries, 1. A. Nolta, H. E. Heslop, and M. K. Brenner. Professors S. Asano and K. Tani presented new studies on gene transfer into primates. Among the highlights were the new papers on gene transfer presented by G. Wage maker, N. G. Abraham, and M. Onoderea from R. M. BJaese's group. The use of BMT for organ transplant and autoim mune disease was updated and a representative paper is presented in this volume."

vi The word ppotein, coined one and a half century ago from the 1TpOTE:toa ("proteios" = of primary importance), underlines the "primary importance" ascribed to proteins from the time they were described as biochemical entities. But the unmatched compl~xity of the process involved in their biosynthesis was (understandably) overlooked. Indeed, protein biosynthesis was supposed to be nothing more than the reverse of protein degradation, and the same enzymes known to split a protein into its constituent amino acids were thought to be able, under adequate conditions, to reconstitute the peptide bond. This oversimplified view persisted for more than 50 years: It was just in 1940 that Borsook and Dubnoff examined the thermodynamical aspects of the process, and concluded that protein synthesis could not be the reverse of protein degradation, such an "uphill task being thermody- namically impossible *** * " The next quarter of a century witnessed the unravelling of the basic mechanisms of protein biosynthesis, a predictable aftermath of the Copernican revolution in biology which followed such dramatic de- velopments as the discovery of the nature of the genetic material, the double helical structure* of DNA, and the determination of the ge- netic code. Our present understanding of the sophisticated mechan- isms of regulation and control is a relatively novel acquisition, and recent studies have shed some light into the structure and organi- zation of the eukaryotic gene.

Concise yet comprehensive, Cytology: Diagnostic Principles and Clinical Correlates is a practical guide to the diagnostic interpretation of virtually any cytological specimen you may encounter. This highly useful bench manual covers all organ systems and situations in which cytology is used, including gynecologic, non-gynecologic, and FNA samples, with an in-depth differential diagnosis discussion for all major entities. As with previous editions, the revised 5th Edition focuses on practical issues in diagnosis and the use of cytology in clinical care, making it ideal for both trainee and practicing pathologists. Uses easy-to-read, bulleted text to provide a quick review of key differential diagnoses, indications and methods, cytomorphologic features, clinical pearls, and tissue acquisition protocols for specific entities. Includes coverage of patient management in discussions of pertinent clinical features and emphasizes clinical correlation throughout. Examines the role of immunohistochemistry, flow cytometry, and molecular biology in resolving difficulties in interpretation and diagnosis. Features more than 550 full-color illustrations that provide a real-life perspective of a full range of cytologic findings. Discusses hot topics such as new diagnostic biomarkers and their utility in differential diagnosis, the latest Bethesda System classifications/terminology, new techniques, and new adjunct tests. Provides an in-depth analysis of common diagnostic pitfalls to assist with daily sign-out and reporting. Includes a video on how to perform fine needle aspiration biopsy, from the patient interview and precautions to demonstration of techniques. Enhanced eBook version included with purchase. Your enhanced eBook allows you to access all of the text, figures, and references from the book on a variety of devices.

In 1980, the IVth International Cyclic Nucleotide Conference was held in Brussels. As this meeting attracted many investigators involved in cyclic nucleotides and calcium role in intracellular regulation, it was thought that this opportunity could be used to organize, prior to the Congress, an in-depth introductory course on the subject. This was carried out as a NATO Advanced Study Institute. The participants included Ph. D. students and M. D. s engaged in a research training, but also fully trained and well known researchers who wanted a refresher course on the whole subject. During the course, most of the participants and lecturers asked to be provided with a text summarizing the basic lectures of the course. This book was therefore conceived as a basic textbook on the regulation and action of intracellular signal molecules, concentrating mainly on cyclic nucleotides and calcium. It was deliberately kept at a basic level. We would therefore be happy if it could be used as an introduction for interested M. D. s or Ph. D. s working in other fields or entering this field and as a general refresher for researchers interested in the subject. For this reason, very general schemes have been asked of the authors, along with reading lists of available reviews rather than extensive bibliographies. The editors should like to thank the NATO Scientific Affairs Committee for having supported the course and Mrs. Gh. Wilmes who prepared the manuscripts. S. SWILLENS J. E.

The fetal period of human growth and development has become an area of intense study in recent years, due in large part to the development of diagnostic ultrasound. More than 2,000 articles have been published in the last five years describing anatomy and pathology in utero, as reflected in sonographic images. Yet, no stan dard reference exists to correlate these images with fetal gross anatomy and at tempts to draw parallels from adult structure have often led to false assumptions. The dictum "the newborn is not a miniature adult" is all the more valid for the fetus. This text aims to provide a comprehensive reference for normal sectional anat omy correlated with in utero ultrasound images. In addition, magnetic resonance images of therapeutically aborted or stillborn fetuses are paired with similar gross sections to serve as a foundation upon which current in vivo studies may build. Lastly, a miscellaneous section illustrates several anatomic points useful in the understanding of fetal anatomy. These points include the changing anatomy of the fetal brain during gestation and the anatomy of the meninges, the fetal heart, and ductus venosus. It is our hope that this atlas will provide a clear picture of fetal anatomy, rectify some of the confusion which exists in antenatal diagnosis, and stimulate further interest in fetal development."

Since the appearance of photosynthesis on our planet, all living organisms have been facing a new abundant, extremely reactive element, oxygen. This element is used for the synthesis of highly energetic compounds, but can also generate molecules capable of damaging constituents of living structures, including proteins, nucleic acids and lipids. It is therefore no surprise that all biological organisms have evolved multiple and sophisticated ways to reduce the detrimental effects of oxygen. For cells and tissues of highly organized animals, particularly cells of the immune system, superoxidation products play an important role, via oxidative stress, in activation, inflammation and viral and bacterial infections. We must be grateful to Drs. C. Pasquier, C. Auclair, L. Packer and R. Olivier for having brought together many specialists in an international meeting held in Paris in March 1993, at the Ministry of Research. This book comprises an impressive amount of recent knowledge, a real mine for the reader in this fast developing field of research. Furthermore, we should not forget that this basic research may lead in the future to new therapeutic approaches to the most important pathologies of the latter part of this century, including AIDS.