Prior to the emergence of the sliding filament model, contraction theories had been in abundance. In the absence of the kinds of structural and biochemical information available today, it has been a simple matter to speculate about the possible ways in which tension generation and shortening might occur. The advent of the sliding filament model had an immediate impact on these theories; within several years they fell by the wayside, and attention was redirected towards mechanisms by which the filaments might be driven to slide by one another. In terms of identifying the driving mechanism, the pivotal observa tion was the electron micrographic indentification of cross-bridges extending from the thick filaments. It was quite naturally assumed that such bridges, which had the ability to split ATP, were the molecular motors, i.e., that they were the sites of mechanochemical transduction. Out of this presumption grew the cross-bridge model. in which filament sliding is presumed to be driven by the cyclic interaction of cross-bridges with complementary actin sites located along the thin filaments."

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.

While many people practice yoga simply because it helps them feel good, the physiological basis for yoga's effects on the body and mind is often unknown or misunderstood. Understanding these physiological concepts can help to deepen your yoga practice. The Physiology of Yoga separates speculation from fact by examining how the body responds and adapts to yoga within many systems of the body: musculoskeletal, nervous, respiratory, cardiovascular, lymphatic, immune, endocrine, reproductive, and digestive. Straightforward explanations guide you in sorting through conflicting information about what yoga really can help you achieve and in evaluating whether certain yoga methods provide benefits to any or all of those systems. You can experiment with concepts through Try It Yourself sidebars, which focus on mindful movement, meditation, and breathing. The 14 Myth or Fact sidebars explore popular claims about yoga, such as whether a shoulder stand can stimulate the thyroid or if twists can detoxify the liver. You'll get the most current research to determine the validity of various claims so you can avoid practices that could be harmful or counterproductive and can decide for yourself what works for your practice. Finally, experience firsthand how yoga affects your physiology by exploring specific yoga poses and four sequences. Each sequence explains which of the physiological principles from the earlier chapters may be most prevalent in that sequence. With The Physiology of Yoga, you or your students can navigate all the conflicting views and opinions about the impact of yoga and learn to practice yoga while fully enjoying the benefits of mindful movement. CE exam available! For certified professionals, a companion continuing education exam can be completed after reading this book. The Physiology of Yoga Online CE Exam may be purchased separately or as part of The Physiology of Yoga With CE Exam package that includes both the book and the exam.

During the past three decades, histology has seen enormous progress, thanks to new techniques and new investigation instruments. Numerous discoveries of important structures and morphofunctional phenomena have been described in a wealth of papers of ever increasing size and complexity. These publi cations have become difficult to follow, not only because of their number, but also because of a disparity of terminology and the multitude of synonyms employed by different authors. All of this makes reading and comprehension of the progress that has been achieved laborious, even for histologists, but especially for students, researchers in other basic branches of medicine, or clinicians who have to consult histological texts during their studies or investigations. In order to facilitate the orientation of all those interested in histology, a concise and practical volume in encyclopedic style, defining and, at the same time, illustrating fundamental histolog ical terms, enumerating synonyms, and describing morpho functional phenomena has become necessary, both because a work of this genre does not exist and because the list of Latin terms elaborated by the International Anatomical Nomenclature Committee in 1977 does not give illustrations or definitions of histological terms. The present work attempts to redress this deficiency."

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.

In the ever-expanding field of heart research the needs of established re searchers, students and general readers can vary considerably, making it difficult therefore to cater for all types of audience within a single volume. The aim of this book has been to provide a comprehensive and up-to-date review of the structure of the heart, including its cell biology. The ultrastructure of the working myocardium and all portions of the conduction system, together with their development, is covered in detail. Also included are chapters on the morphometry of cardiac muscle, the innervation of the heart, cardiac hyper trophy and regeneration, and the development of the coronary circulation. A detailed review of cardiac muscle in cell culture is also provided. It is to be hoped that readers, whatever their background, will find the information contained herein useful for their needs. This work was supported by a grant from the National Heart Foundation of Australia. The authors wish to gratefully acknowledge the following people for their invaluable assistance in preparation of the manuscript: Professor Yasuo Uehara, D'r. Takashi. Fujiwara, Dr. Peter Baluk, Dr. Seiji Matsuda and Bill Kaegi for providing unpublished micrographs; Fabian Bowers, Patricia Murphy and Janet Bennett for typing; and Lucy Popadynec, Nella Puglisi, Maggie Mackie, Mary Delafield and Liana Butera for assistance with references and figure preparation. THE AUTHORS Contents A. General Introduction 1 Morphology of Cardiac Muscle 8 B."

The progress in Micromorphology and Biochemistry of the last decades has led to a rather far reaching understanding of the function of the genes. Much is also known about their morphological organization within the cell, particularly their reduplication and segregation in connection with the process of cell division. The intensive light microscopic studies of the earlier cytological era on cell division and chromosomes, which laid the basis for this understanding are very comprehensively covered by WASSERMANN (1929) in his masterly contribution "Wachstum und Vermehrung der lebendigen Masse" in this handbook. There exist also many more recent reviews on chromosomes and on cytogene tics (e. g. SWANSON, 1960; MAZIA, 1961; TURPIN and LEJEUNE, 1965; WmTEHousE, 1969; HAMERTON, 1971; FORD, 1973). However, although some of them cover the more recent findings in man, they have either had to rely on more favorable species for detailed basic information or handled cytogenetic problems from a more practical and clinical point of view. Since moreover, the last few years have brought a flood of new information on chromosomes due to new cytological techniques, a new review on human chromosomes would seem justified within the frame of this handbook. This review will be restricted to human somatic chromosomes, i. e. it wi11leave out meiosis, and will provide information on other species only if this seems necessary for increased clarity."

Uncontrolled proliferation of vascular smooth muscle cells (SMC) in response to vessel injury is a problem with a considerable therapeutic impact. Specifically, restenosis after percutaneous transluminal coronary angioplasty (PTCA) is a clinical problem without any effective drug therapy so far. Thus, there is need for an improved drug therapy but also for an improved understanding of the pathophysiology of growth control in SMC. Cyclooxygenase products, such as prostaglandins and thromboxane, are intimately involved in growth responses. Vasodilatory prostaglandins, such as PGI, PGE or their analogues, have 2 1 been shown to inhibit SMC proliferation. There is also evidence for a markedly increased endogenous prostaglandin production during neointirna formation under the influence of growth factors which includes induction of COX-2. These data suggest that prostaglandins might be considered both targets and tools of growth control. However, there are still many open questions, including the possible interaction of prostaglandins with other growth modulating factors, in particular NO, the intracellular signal transduction pathways and the role of oxidative stress."

A major vehicle for the transition of carrier-mediated drug delivery from a theoretical/experimental status to one with practical uses has been the NATO Advanced Studies Institute series "Targeting of Drugs." Three previous ASls of the series 1-3], also held in Cape Sounion, dealt with carriers of natural and synthetic origin, their preparation and drug incorporation as well as a wide range of applications. This book contains the proceedings of the 4th NATO ASI "Targeting of Drugs: Anatomical and Physiological Considerations" held in Cape Sounion, Greece during 20 June - 1 July 1987. Historically, carrier systems have been chosen on the basis of selective affinity for target sites. For instance, monoclonal antibodies bind selectively to antigens on the surface of cells and the same applies to ligands such as certain glycoproteins which bind to cell receptors. Colloidal carriers on the other hand, are "passively" targeted to the reticuloendothelial system. However, effective drug delivery depends not only on demonstration of affinity of the carrier system for its target but also, and perhaps crucially, on the way(s) by which the carrier-drug entity interacts with the interposed biological milieu. The book deals in depth with a number of biological milieus as travelled space for carriers en route to their destination, difficulties arising from unfavorable milieu-carrier interactions and ways to circumvent such difficulties. It also identifies, when possible, situations where proposed uses would or would not be realistic and provides perspectives for future goals.

The contributions to this volume were presented at a Symposium entitled "Current Topics in Muscle and Nonmuscle Motility" held in Dallas 19-21 November 1980 under the auspices of the A. Webb Roberts Center for Con tinuing Education, Baylor University Medical Center Dallas, and the Univer sity of Texas Health Science Center at Dallas. This very useful opportunity for a group of active investigators in motility to meet and discuss their latest findings was made possible in part by the income from an endowment fund established by a generous gift from Dr. Albert P. D'Errico in the Baylor University Medical Center. Dr. D'Errico was the first formally-trained neurosurgeon to practice in the Dallas area, the first Chief of Neurological Surgery, and a member of the Medical Board of the Baylor University Medi cal Center Dallas (1947 -1964). The income from this fund is used to promote the dissemination of up-to-date information in the Neurosciences, to provide intellectual stimulation, to add to the fund of knowledge, and improve the skills of neurosurgeons, neurologists, internists, and others in specialized fields of medicine. We are all indebted for this generous gift that made this enriching educational experience possible. We are also grateful for support the Symposium received from Electron Microscopy Sciences, Forma Scien tific, J. E. O. L. USA, Inc. , Ladd Research Industries, M. J. O. Diatome Co. , Or ganon Co. , Upjohn Co. , G. D. Searle & Co. , and Smith, Kline and French. Robert M.

to Mechanics of Human Movetnent by James Watkins Scottish School oj Physical Education lordanhill College oj Education, Glasgow, Scotland 1983 M. TP PRESS LIM. ITED . . . . a member of (he KLUWER ACADEMIC PUBLISHERS GROteP BOSTON / THE HAGUE! DORDRECHT ! LANCASTER " Published by MTP Press Limited Lancaster, England Copyright (c) 1983 MTP Press Limited Softcover reprint of the hardcover 1st edition 1983 First published 1983 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior permission from the publishers. British Library Cataloguing in Publication Data Watkins, James An introduction to mechanics of human movement 1. Human locomotion I. Title 612476 QP303 ISBN-13: 978-94-011-7815-0 e-ISBN-13: 978-94-011-7813-6 DOl: 10. 1007/978-94-01\-7813-6 Typeset by Blackpool Typesetting Services Ltd. , Blackpool. Bound by WBC Bookbinders Ltd. , Maesteg, Mid Glamorgan. Contents PREFACE vii INTRODUCTION Mechanics of human movement 1 1. 1 1. 2 Forms of motion 2 1. 3 Units 3 LINEAR MOTION 2 2. 1 Distance and speed, displacement and velocity 4 2. 2 Acceleration 11 2. 3 Vector and scalar quantities 13 2. 4 Mass, inertia and linear momentum 21 2. 5 Force and Newton's First Law of Motion 21 2. 6 Newton's Law of Gravitation (law of attraction); gravity and weight 23 2. 7 Newton's second law of motion; the impulse of a force 27 2. 8 Units of force 31 2.

The various chapters of this monograph were originally presented as papers in a Symposium on Joints and Bones which the editor organized for the VIII Inter national Congress of Anatomists held in Wiesbaden, Germany in August 1965. Each chapter represents original research on the structure and/or function of joints and bones. Preparing the manuscripts of these papers for publication required more time than originally anticipated and the editor hereby acknowledges his sincere appre ciation to the various authors for their help and patience. He also wants to express his special thanks to Mrs. ANTOINETTE CATRON, his editorial assistant, without whose help the task would still be unfinished. The interest and assistance of the staff of Springer-Verlag in the publication of this monograph is also greatly appreciated. Ann Arbor, Michigan, USA. February 1966 F. GAYNOR EVANS Contents Electron Microscopy of Normal Synovial Membrane. D. V. DAVIES, and A. J. PALFREY .............................. 1 Biomechanics and Functional Adaption of Tendons and Joint Ligaments. A. VnDIK . . . . . . . . . . . . . . . . . . . . . . . . .. . 17 . . . . Dynamic Considerations in Load Bearing Bones with Special Reference to Osteosynthesis and Articular Cartilage. J. M. ZAREK .. . . . . . . . 40 Intravital Measurements of Forces Acting on the Hip-Joint. N. RYDELL. .. 52 The Ergonomic Aspects of Articular Mechanics. M. A. MACCONAILL . . . . 69 A Longitudinal Vital Staining Method for the Study of Apposition in Bone. M. ]. BAER, and]. L. ACKERMAN. . . . . . . . . . . . . . . . . 81 . . . An Evaluation of the Use of Bone Histology in Forensic Medicine and Anthro pology. D. H. ENLOW. . . . . . . . . . . . . . . . . . . . . 93 . . . .

Several methods have been used to demonstrate the vasculature of different organs in man and other species. Many attempts to evaluate the precise microangioarchitecture of organ systems remained unproductive, others were controversial. The development of electron microscope in thirties opend new perspectives in researching microvascular systems. Transmission electron microscopy provided a two-dimensional view on microcirculatory system at higher magnifications, however, its standardization was delayed unnecessarily. The use of methyl methacrylate and related compounds for obtaining replicas of vascular beds, and their study in scanning electron microscope opened a new window in micromorphological research. For the first time, a three-dimensional image analysis of the vascular system was possible. The microvascular corrosion casting method has meanwhile attracted the interest of many contemporary scientists. Its application to medical and biological problems justify it to be used as a routine method for microvascular investigations. The first investigators who used this method, focused either on methodological details or they dealt with the normal microanatomy of organs. The advantages of this method in demonstrating pathological microvascular patterns are also evident.

The ability to "immortalize" immunologically-useful cells by hybridization with a unique cancer cell has revolutionized serological studies and has revealed new potential applications in all fields of biological sciences. This volume presents the studies from a highly successful national symposium on Hybridomas and Cellular Immortality held November 1981 in Houston, Texas. The individual chapters exhibit the diversity of topics discussed during the meeting. These include emphasis on the origin of antibody diversity, Band T lymphocyte differentiation, applications of monoclonal antibodies in studies of histocompatibility, tumor, and viral antigens, plus the use of somatic cell hybridizations for studying T cell products. Three papers focus on the emerging methodologies of in vitro primary immunizations for both humoral and cell-mediated immunities, relevant for coupling with hybridoma technology. There is a useful mix of general (methods) and specific (applications) chapters. A unique aspect of the book is the presentation of both recent research findings with concise descriptions of the state of the art methodologies. It is anticipated that this work will be of interest to a wide audience of practioners in biomedical research. Hopefully, the information contained will foster new and imagi native ideas in hybridoma applications. Baldwin H. Tom, Ph.D. James P. Allison, Ph.D. vii CONTENTS PART L INTRODUCTION TO HYBRIDOMAS 1 Somatic Cell Hybrids and Hybridomas Baldwin H. Tom 3 1. Somatic Cell Hybrids 8 Hybridomas. * * * * * 2.

Leading workers in the field of human reproduction provide both basic knowledge and useful practical information in this book about the most critical phase in the development of a new human being: the first twelve weeks of life. The period from fertilization and implantation to the end of the first trimester is still insufficiently understood and marks a new frontier. The knowledge necessary for applying our present diagnostic capabilities and for venturing into the problematic areas of fertilization technology and embryonic treatment is made easily available in this comprehensive textbook. The book is divided into two parts. The first presents basic information about physiology, anatomy, in vivo investigations, biochemistry and legal aspects. The second part focuses on pregnancy development, monitoring and the clinical diagnosis and management of disorders in the early stages of life. A full section is devoted to assisted conception and the newest possibilities in fertilizationtechnologies, whereby the ethical aspects are also discussed.

In this book, concerned with the spatial and structural repre- sentation of the cell and its particular specializations, the author hasdeviatedconsiderablyfrom the usual planfor other books related to this subject and has presented the illustrative material in the form of detailed and accurate drawings. The layout of the book provides the reader with a briefnarrative accountoftheparticularorganelleaccompanied byafull-plate illustration on the facing page. Most ofthe narrative accounts areaccompaniedbyashortbibliographyofgermanereferences in the event the reader desires to pursue the subject matter in greater depth. In my estimation there is no other presentation currentlyavailablewhich utilizes thisapproach to demonstrate the cellular components and their associated morphophysi- ology with such elegance. Thetextisclearlywrittenand,althoughtheindividualaccounts are brief, they are highly informative with all ofthe important details being provided. The accuracy ofthe textural presenta- tions and the continuity ofexpression provide strong evidence that the author has spent an enormous amount of time in preparing the text and in painstakingly drawing the illustra- tions. Certainly, an obvious strength ofthis volume is the high qualityoftheillustrativerenditions, allofwhichweredrawnby Dr. KRSTIC. These attest to the profound and comprehensive nature of the author's knowledge of the field of cellular and structural biology. This book is truly a work oflove and art by one who is gifted both didactically and artistically. Dr. KRSTIC should be con- gratulated for providing us with an extremely accurate and detailedaccountofthe 2-dimensional, andinmanycasesthe 3- dimensional, view of the cell and its component organelles. It has no equal.

In 1954, when I obtained my B. Sc. (Honours School) degree in Zoology, I was asked by my advisor, the late Professor Vishwa Nath, to make comparative cytological studies of oogenesis in birds for my M. Sc. (Honours School) thesis submitted to the Panjab University in 1956. Using the classical techniques of cytology, I studied the various aspects of follicle growth and atresia in five species of birds. Professor Vishwa Nath, who himself devoted most of his life to the study of the comparative cytology of gametogenesis in animals, was so much impressed by my findings on avian oogenesis that he asked me to continue my research work for the Ph. D. degree under his supervision. During my research work on avian oogenesis, I became very much interested in further comparative study of ovarian follicles in vertebrates and thus decided to make comparative, morphological and histochemical studies of ovarian follicles in reptiles, birds and mammals. Actually, very little information was available in this regard in 1957 when I started working for the Ph. D. degree. In subsequent years, I and my numerous dedicated and highly motivated M. Sc. and Ph. D. students con tinued to make comparative, morphological, histochemical, biochemical and physiological studies of ovarian follicles in all groups of vertebrates. In connection with the subject of this book, I would like to make special mention of my two brilliant students, namely Dr. S. K. Varma and Dr. R. K."

The third volume and the other two volumes (Volume 1 available, Volume 2 due december 1999) offer the scientific community the works and thoughts of Santiago Ramon y Cajal by the faithful rendition of the original Spanish version of the Texture of the Nervous System of Man and the Vertebrates (1899 1904), with additional facts contained in the French translation (1909 1911). These non-English versions are being quoted an average of 200 times yearly in the scientific literature. The collection will represent the "definitive Cajal to be used by scientists and scholars interested in the original thoughts of probably the most prominent neuroscientist of all times. Unique features of the present work include: Only authorized English translation of the original Spanish text, adhering as much as possible to the letter, with correction of the obvious errors already predicted by Cajal in his Preface. Added facts appearing in the French version, with correction of old as well as new errors, the latter probably due to inaccuracies in translating into French some nuances of the Spanish language. Uniform of nomenclature according to contemporary scientific English. Annotations on Cajal s changing concepts over time, the elucidation of certain structures that do not have present day equivalents, and explanations of the many symbols appearing in illustrations but not mentioned in the corresponding original legends. Most illustrations are reproductions of Cajal s original art work, still extant at the Cajal Museum in Madrid, with cross references to figure numbers of the Spanish and French versions. Citations are given by author and year in the text, with an alphabetical list at the end of the volume, completed and corrected for accuracy against original publications. Taxonomy glossary of species appearing in the text, with present scientific names, and their colloquial English counterparts. In sum, the collection represents the "definitive Cajal to be used by scientists and scholars interested in the original writings of probably the most prominent neuroscientist of all times."

The present volume contains the edited transcript of a Totts Gap Colloquium held May 19-21, 1980 sponsored by the Muscular Dystrophy Association. The aim of the colloquium was to bring into focus data relating to cell membranes that might contribute to understanding the pathogenic mechanism of Duchenne muscular dystrophy. A major impediment to progress in understanding the patho genesis of muscular dystrophy has been the failure, so far, to identify the basic genetic defect. Pending the identification of the genetic lesion in Duchenne dystrophy and, in view of scattered but persistent indications of a basic membrane disturbance, it seemed worthwhile to explore in open dialogue the current state of knowledge of membrane morphology and chemistry with an eye to possible leads for further investigation. The participants, drawn from a variety of interested disciplines, attempted to synthesize and reconcile their findings and to identify crucial areas of ignorance in need of exploration. For the most part they avoided specialized jargon and spoke in a language that could be understood by the rest of the group. Apart from providing a review of widely varying approaches to the study of the composition and behavior of cell membranes, the discussions brought together current think g on strategies and approaches to the study of the pathogenesis of muscular dystrophy. Already the personal contacts made at the colloquium have led to new inter-institutional collabora tive investigations."

Alfons Staudach has been a long-time member of the Anatomic Institute of Karl Franzens University in Graz, where he has devoted particular atten tion to the deeper understanding, appreciation and visualizion of gross ana tomic details. In this work the author has achieved correspondence between sonograms and anatomic sections with a consistency and persuasiveness unequaled in all the previous literature on diagnostic ultrasound. The various planes of section andtheir characteristic features, and indeed the entire format of the text, are designed to provide even the less experienced sonographer with a valuable basis for conducting his examinations. The more experienced reader will find essential information on topographic relations and organ development that is not available in any other work dealing with fetal ana to y. I am certain that my high estimation of this volume will prove justified, and that it will provice its readers with a useful and stimulating resource. Univ. -Prof. Dr. Walter Thiel (Chairman of the Anatomic Institute of the University of Graz) Foreword Anyone setting this book down after an initial perusal must wonder why such a reference was not available ten years ago. The meticulous and fas cinating juxtaposition of gross anatomic sections with sonograms, together with explanatory drawings and many practical guidelines, should enable even the novice accurately to identify details and interpret sonographic findings with precision."

When I was asked by the late Professor Wolfgang Bargmann in 1973 to write the continuation of his review article on the epiphysis cerebri published in the present Handbuch Series in 1943 I felt greatly flattered and readily agreed, not knowing that it is virtually impossible for a single person to cover comprehensively the vast field of pineal research carried out over the last 35 years. Although I have done my best to include as much of the relevant work as possible (up to July 1979), I am constantly haunted by the references I have missed. I sincerely apologize for these omissions: first, to the authors of these papers, who, in addition to working on one of the most stony grounds of biological research, now may experience the additional frustration of not being quoted; secondly, to my fellow pinealogists or pinealogists-to-be, who may carry out painstaking experiments only to find that they have been done before, or who may be led astray because of lack of information. Nevertheless, I do hope that this monograph will fulfil its aim, namely to show how pineal research has progressed over the last 35 years and where it stands today. It is hoped that it will aid in planning relevant experiments and that it shows which approaches to the pineal problem would be better avoided.

Leading international experts contribute to this selection of reviews covering the merging fields of growth factors, differentiation factors, and cytokines. These appear to play fundamental roles in a wide variety of physiological and pathophysiological processes that include the regulation of growth in normal and malignant cells, embryogenesis, the immune response, wound healing, inflammation, and atherogenesis. The major aspects of recent research and development are discussed, providing an important update in this pioneering field.

The advantages of obtaining a completely defined environment for the growth of cells in vitro were recognized very early in the history of cell culture (Lewis and Lewis, 1911). Continued interest in the nutritional requirements of cells in vitro and in providing an optimal environment for cells led to the development of the complex nutrient mixtures available today in many media (Waymouth, 1972; Ham, 1965). However, serum remained an essential component of medium for the growth of most cell types in culture. The question of what factor (or factors) in serum was essential for cell growth and survival remained unanswered for several decades. Initially, experiments were designed to purify the "active component" of serum for the growth of cells in culture. These experiments identified fetuin (Fisher et at., 1958) and nonsuppressible insulinlike activity (Temin et at., 1972) as important components of serum. However, the complexity of serum and the very low levels of active components in serum hindered progress in identi fying and isolating serum factors."

Since the thalidomide (Contergan) tragedy about 30 years ago the induction of prenatally-induced morphological or functional defects has been an area of extensive research. Risk assessment of prenatally-induced adverse health effects is still a difficult task from both experimental data as well asfrom observations in humans. In the contributions to this book three major aspects are dealt with: - Quantitative extrapolations of experimental data to the situation possibly relevant for man. - The significance for a risk assessment with respect to man of minor or rare structural abnormalities observed in experimental studies - The future need to assess congenital dysfunctions (e.g. of the hormone or the immune system) beside the present evaulation of structural defects. Limitations as well as gaps of the present knowledge in this area of basic and applied research are pointed out. Since the results of prenatally-induced lesions may manifest themselves not only pre- but often not before late postnatally, numerous aspects of structural and functional abnormaldevelopment must be studied in experimental and clinical investigations.

H.P. HIGER 1 In the seventeenth century people dreamed about a machine to get rid of evil spirits and obsessions, which were thought to be the main source of mis fortune and disease. I am not going to question this approach, because in a way it sounds reasonable. They dreamed of a machine that would display im ages from the inner world of men which could be easily identified and named. Somehow these are the roots of MR imaging. Of course, we now view disease from a different point of view but our objectives remain the same, namely to make diseases visible and to try to characterize them in order to cure them. This was the reason for setting up a symposium on tissue characterization. About 300 years later the clinical introduction of MRI has great potential for making this dream come true, and I hope that this symposium has con stituted another step toward its realization. When Damadian published his article in 1971 about differences in T1 relaxation times between healthy and pathological tissues, this was a milestone in tissue characterization. His results initiated intensive research in to MR imaging and tissue parameters. Actually his encouraging discovery was not only the first but also the last for a long time in the field of MR tissue characterization.