Myelin

The emergence of myelin 425 million years ago marked a turning point in evolution. Consider for a moment the invention of insulated wire, which allows for the transmission of electrical current. Functioning in a similar way, the membrane surrounding nerve fibers, or myelin, enables the remarkable acceleration of nerve impulses. Surprisingly, myelin occupies nearly half the volume of the human brain and is critical for our intellectual and motor performance. Without myelin, our thoughts and our movements would suffer overwhelming delays. We owe our reflexes to myelin: it is what makes us brake when a child dashes out onto the road, or snatch away a hand absent-mindedly placed on a burning hot stove. When damaged, myelin can lead to irreversible disability, cognitive decline, and sensory impairments. The study of myelin's role in the conduction of nerve impulses has led to a better understanding of several diseases including multiple sclerosis, Guillain-Barre syndrome, Charcot disease (ALS), and Niemann-Pick disease.

Magnetic resonance imaging (MRI) is now considered the imaging modality of choice for the majority of disorders affecting the central nervous system. This is particularly true for gray and white matter disorders, thanks to the superb soft tis sue contrast in MRI which allows gray matter, unmyelinated, and myelinated white matter to be distinguished and their respective disorders identified. The pre sent book is devoted to the disorders of myelin and myelination. A growing amount of detailed in vivo information about myelin, myelination, and myelin dis orders has been derived both from MRI and from MR spectroscopy (MRS). This prompted us to review the clinical, laboratory, biochemical, and pathological data on this subject in order to integrate all available information and to provide im proved insights into normal and disordered myelin and myelination. We will show how the synthesis of all available information contributes to the interpretation of MR images. After a brief historical review about the increasing knowledge on myelin and my elin disorders, we propose a new classification of myelin disorders based on the subcellular localization of the enzymatic defects as far as the inborn errors of me tabolism are concerned. This classification serves as a guide throughout the book. All items of the classification will be discussed and, whenever relevant and possi ble, be illustrated by MR images.

Myelin: Biology and Chemistry provides in-depth reviews and discussions regarding recent findings in the biology and chemistry of myelin. Topics are interdisciplinary and carry readers from the cellular level to that of the gene. Research in demyelinating diseases (naturally occurring and experimentally produced) is described and emphasizes autoimmune and virally induced mechanisms. Advances in molecular biology, such as those that provide details of the structures of the major myelin proteins, demonstrate the control of their synthesis, and explore the mutations within their genes that disrupt the process of myelination, are discussed in depth. Myelin: Biology and Chemistry will be an important addition to the libraries of molecular biologists, biochemists, cell biologists, physical chemists, immunologists, virologists, and pathologists involved in the study of myelin.

In this, the post-genomic age, our knowledge of biological systems continues to expand and progress. As the research becomes more focused, so too does the data. Genomic research progresses to proteomics and brings us to a deeper understanding of the behavior and function of protein clusters. And now proteomics gives way to neuroproteomics as we begin to unravel the complex mysteries of neurological diseases that less than a generation ago seemed opaque to our inquiries, if not altogether intractable. Edited by Dr. Oscar Alzate, Neuroproteomics is the newest volume in the CRC Press Frontiers of Neuroscience Series. With an extensive background in mathematics and physics, Dr. Alzate exemplifies the newest generation of biological systems researchers. He organizes research and data contributed from all across the world to present an overview of neuroproteomics that is practical and progressive. Bolstered by each new discovery, researchers employing multiple methods of inquiry gain a deeper understanding of the key biological problems related to brain function, brain structure, and the complexity of the nervous system. This in turn is leading to new understanding about diseases of neurological deficit such as Parkinson’s and Alzheimer’s. Approaches discussed in the book include mass spectrometry, electrophoresis, chromatography, surface plasmon resonance, protein arrays, immunoblotting, computational proteomics, and molecular imaging. Writing about their own work, leading researchers detail the principles, approaches, and difficulties of the various techniques, demonstrating the questions that neuroproteomics can answer and those it raises. New challenges wait, not the least of which is the identification of potential methods to regulate the structures and functions of key protein interaction networks. Ultimately, those building on the foundation presented here will advance our understanding of the brain and show us ways to abate the suffering caused by neurological and mental diseases.

Traditionally, oligodendrocytes have been assumed to play a minor supporting role in the central nervous system and their importance has generally been overlooked. For the first time, this book provides a dedicated review of all of the major aspects of oligodendrocyte biology, including development, organization, genetics, and immunobiology. Later chapters emphasize the importance of this underestimated cell to the mammalian central nervous system by exploring the role of myelin synthesis and maintenance in neural disease and repair. Particular attention is paid to multiple sclerosis (MS), arguably the prime example of an acquired demyelinating disease, with detailed examinations of the current concepts regarding demyelination, oligodendroglial damage, and remyelination in MS lesions.

My colleagues and I have been gratified by how rapidly the first edition of Myelin has been aeeepted as a standard referenee work by myelin researehers. This is undoubtedly the primary faetor aecounting for the high rate of reeidivism among the authors with respeet to preparation of a seeond edition; eleven of the original twelve contributors were again involved. Four new authors (Wendy Cammer, Marjorie Lees, Ute Traugott, and Seymour Greenfield) have also eontributed to the present volume. This new edition retains many aspects of the format of the original, even including use of the same chapter headings. Thus, comments in the preface to the first edition concerning the level at which material is presented and the relationships between chapters covering the "basic" and "c1inical" material are still applicable. Despite certain similarities in overall organization, comparison of the present edition with the original demonstrates that our eHorts to restriet expansion in the length of the text were not notably successful; the new edition is mueh lengthier than the original. Nevertheless, the increase in text length is modest relative to the increase in information in the seven years separating the preparation of the two editions. Most of the material in the individual chapters has had to be completely redone in order to include this new information. For example, our view of the metabolism of myelin increasingly must take cognizance of a very rapidly turning over pool of certain of its components.

This book presents the latest exciting advances in understanding of the structure and function of myelin in the central and peripheral nervous systems under normal and pathological conditions. Readers will find state of the art information from the perspectives of both basic neuroscience and clinical neurology and neuropathology. Detailed attention is paid to the findings and implications of recent research on the myelin-forming glial cells such as oligodendrocytes and Schwann cells. The discussion of myelin pathology encompasses a wide range of diseases and conditions, including, for example, multiple sclerosis, Pelizaeus-Merzbacher disease, traumatic brain and spinal cord injuries, brain tumors of glial cell origin, Charcot-Marie-Tooth disease, immune-mediated neuropathy, and diabetic neuropathy. The authors comprise researchers at the cutting edge of biotechnology and experts in the diseases discussed. The clearly written text is supported by numerous high-quality light and electron microscopy, CT, and MR images.