Brain edema is a simple phenomenon - an abnormal increase of brain tissue volume by the increase of brain tissue water content. However the etiology is not simple and relating to a wide variety of neurological disorders including ischemia, trauma, tumor, hemorrhage and hydrocephalus. It is still a major cause of death in the neurological/neurosurgical ward. This volume is an up-to-date report on progress in brain edema research, diagnosis and treatment, including papers presented at the 12th International Symposium on Brain Edema and Brain Tissue Injury in 2002. Major topics include molecular biology and blood-brain barrier disorders, ischemic and traumatic brain edema, imaging and diagnosis of brain edema, treatment and radiation effect. Various papers in the rapidly growing fields of neuroimaging and molecular medicine are also included.

This volume is a compilation of papers presented at the Tenth International Symposium on Brain Edema held on October 20-23, 1996, in San Diego, California. This follows the sequence of meetings that was initiated 31 years ago in the First International Symposium held in Vienna. Subsequent symposiums were held in Mainz, Montreal, Berlin, Groningen, Tokyo, Baltimore, Bern, and Tokyo CY okohama). A considerable number of papers was chosen from over 100 papers that were received. The organizers wish to thank the Advisory Committee for the excellent work done in selection of the papers. We also wish to thank all the persons who contributed to the success of the Tenth International Symposium, especially the staff who worked behind the scenes. These papers were reviewed, edited, approved or disapproved by the Editorial Board. Those manuscripts that were felt not pertinent to this publication were not accepted by the Editorial Board. Therefore, the excellent quality of those that are in the book are a reflection of the authors' dedication and work and that of those of the Editorial Board in their review process. For the reader's convenience, the papers are structured according to the various disease processes which are associated with the primary topic: hypertension, hydrocephalus, infection, ischemia, tumor, etc. We do hope that the reader will enjoy the articles and that they will provide an impetus and insight for future work.

The Maturation Phenomenon, first described by Ito et al. in 1975, refers to post ischemic changes that develop hours or days after an ischemic insult. The delayed neuronal death of CAl pyramidal cells of the hippocampus is a classic example. The report of the phenomenon boosted research in the field, as it became evi dent that ischemic damage is not a sudden event but a process potentially suscep tible to therapeutic intervention. In September 1990, Ito and collaborators organized the First International Sym posium on "Maturation Phenomenon in Cerebral Ischemia" which was held in To kyo, Japan. The Second Symposium was organized in Tokyo, Japan in March/April 1996. The Third Symposium was held in Pozzilli, Italy in April 1998 and the Fourth Symposium was held in New Orleans, Louisiana, USA in October/Novem ber 1999. This book contains the presentations of the Fifth International Workshop on Maturation Phenomenon in Cerebral Ischemia held at the Rimrock Resort Ho tel in Banff, Alberta, Canada on April 28-May 1, 2002. It outlines the present sta tus of investigations and provides further stimulation for research in this field. The Maturation Phenomenon represents a continuing struggle for survival be tween the acceleration of tissue or neuronal death and the activation of defense mechanisms leading to neuronal recovery. The elucidation of these mechanisms is important for developing the ability to manipulate them during a long-lasting "therapeutic window".

The maturation phenomenon, first described by Ito et al. in 1975, refers to postischemic changes that develop hours or days after an ischemic insult. The delayed neuronal death of CA1 pyramidal cells of the hippocampus is a classic example. The report of the phenomenon boosted research in the field, as it became evident that ischemic damage is not a sudden event, but a process potentially susceptible to therapeutic intervention. Since then a growing number of studies have improved our knowledge on mechanisms of cell death and recovery. This volume contains the presentations of the 4th international symposium, held in New Orleans in October/November 1999, grouped in sections covering apoptosis and/or necrosis, neuronal recovery vs. death, and protection against infarction. It outlines the present status of investigations and provides further stimulation for research in this field.

It has been well recognized that following an ischemic insult many nerve cells of the brain are not killed outright, but may suffer a "delayed neuronal death" or even recover. This led to the concept of "maturation phenomenon" with its main implication that the maturation of ischemic lesions may provide a "window of opportunity" i.e. a period of time when the injury to neuronal elements is still reversible, and during which an application of proper therapeutic measures might be successful. The symposium on Maturation Phenomenon in Cerebral Ischemia was the first international meeting focussed primarily on this subject and the resulting publication contains presentations and discussionsby prominent researchers engaged in this field. This book should stimulate further research on potential of brain tissue for recovery, and particularly with regard to a functional recovery of neurons suffering from chronic ischemic injury.