I. Klatzo – författare

Human greatness has many connotations. Since the requirements for membership in this category are vague and poorly defined, admittance to the Mount Olympus is frequently erratic and subjective, especially in view of a wide "penumbra zone"* of border cases. Nevertheless, rising above a twilight zone of debatable cases, there are individuals whose right for mem­ bership is unquestionable. In science, one of the unequivocal criteria for "greatness" relates to how far one's scientific achievement affects the opening of new horizons, and points to directions for future development and progress. Unveiling new visions can derive only from creative people who conceive original ideas and con­ cepts, and who are daring enough to promote them against the indifference or opposition of the establishment. Maintaining the integrity and the faith to one's own ideals may require extraordinary strength of character, - up to courting persecution or even death, - as happened in the middle ages, and more recently, in the first half of this century with regard to Cecile and Os­ kar Vogt, whose lives and accomplishments are described in this book. Thus the greatness of the Vogts is based both on their penetrating vision of the future for brain research and on the sterling quality of their character, which sustained a "test of fire" during the Nazi years in Germany.

The topic "Cerebrovascular Transport Mechanisms" was chosen by the General Couneil of the International Society of Neuropathology as one of the four main symposia at the IX International Congress of Neuropathology, September 1982 in Vienna. The chairmen of the symposium were asked to structure a program which would cover the reeent devel- opments in this field and which could serve as a background for free communications, relevant to this topic, submitted by the participants of the Congress. Cerebrovascular transport mechanisms refleet the main function of the blood-brain barrier in providing optimaI, homeostatically regulated, biochemical environment for the brain. It is obvious that disturbanees of this function may play a significant role in patho- physiology of various brain disorders.Since the elucidation of the complex blood-brain barrier phenomenon, consisting of various "barrier systems", necessarily requires applica- tion of multidisciplinary approaches, the program of this symposium was structured by evaluation of ultrastructural, cytochemical, physiological, biochemical, pathophysiological and therapeutic aspects of the blood-brain barrier by invited, recognized experts in respec- tive areas. As aresult, this volume of the proceedings of the symposium attempts to summarize much of today's knowledge on cerebrovascular transport mechanisms in health and disease, and is supplemented by the abstracts of free communications dealing with the most reeent research in this field. We hope that this volume wil1 serve both as an introduction and a reference book, and that it wil1 stimulate further research.

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 ischemicinsult many nerve cells of the brain are not killedoutright, but may suffer a "delayed neuronal death" or evenrecover. This led to the concept of "maturation phenomenon"with its main implication that the maturation of ischemiclesions may provide a "window of opportunity" i.e. a periodof time when the injury to neuronal elements is stillreversible, and during which an application of propertherapeutic measures might be successful.The symposium on Maturation Phenomenon in Cerebral Ischemiawas the first international meeting focussed primarily onthis subject and the resulting publication containspresentations and discussionsby prominent researchersengaged in this field. This book should stimulate furtherresearch on potential of brain tissue for recovery, andparticularly with regard to a functional recovery of neuronssuffering from chronic ischemic injury.

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 ischemicinsult many nerve cells of the brain are not killedoutright, but may suffer a "delayed neuronal death" or evenrecover. This led to the concept of "maturation phenomenon"with its main implication that the maturation of ischemiclesions may provide a "window of opportunity" i.e. a periodof time when the injury to neuronal elements is stillreversible, and during which an application of propertherapeutic measures might be successful.The symposium on Maturation Phenomenon in Cerebral Ischemiawas the first international meeting focussed primarily onthis subject and the resulting publication containspresentations and discussionsby prominent researchersengaged in this field. This book should stimulate furtherresearch on potential of brain tissue for recovery, andparticularly with regard to a functional recovery of neuronssuffering from chronic ischemic injury.

The patriarch of experimental pancreas research is REIGNIER DE GRAAF (1641-1673). He carried out the first experiments with dogs in order to ob­ tain fistular secretion (1664). But only few years later, the just arisen interest in the physiology of the pancreas was severely set back by remarks of CONRAD BRUNNER. In 1682, BRUNNER expressed his belief that on the basis of experi­ ments he had carried out the pancreas was a vitally unimportant organ. He overlooked that after ligation of the main duct (discovered in the turkey by HOFMAN in 1641 and in a human cadaver by WIRSUNG in 1642), in the dog an accessory duct (described by SANTORINI in 1724) usually maintains an adequate flow of secretion. EBERLE in his monograph (1834) confirmed the emulsifying capacity of the pancreatic juice which had already been suggested by SYLVIUS (FRAN­ CISCUS DE LE BOE, 1614-1672) and he dealt with the essential enzymatic functions of the pancreatic juice such as amylolysis, lipolysis and proteolysis. Since HEIDENHAIN (1875), we know that for example trypsin (largely isolated by KUHNE in 1867) is situated in the acinar epithelial cells as zymogen in inactive form; it is thought that the action of "acid" on the glandular tissue is needed for inducing the "enzymatic activity". According to what we know now about the central role of acidosis in the activation of zymogen this topic is, of course, of topical interest.