Norman Taslitz

Recovery of the subhuman primate after deep cerebral hypothermia and prolonged ischaemia.

Abstract By employing a simplified technique of autocerebral hypothermic perfusion (without pump or oxygenator) the monkey brain has been cooled to intracerebral temperatures 5–8°C and rendered ischaemic for 1 h with normal recovery in the animals. The efficiency of isolated cerebral cooling was markedly enhanced with exogenous catecholamines and a cephalic ice helmet.

Arrest of cerebral blood flow and reperfusion of the brain in the rhesus monkey

Abstract Rhesus monkeys were subjected to cerebral ischaemia by arresting blood flow to the brain. The carotid and vertebral arteries were temporarily occluded and a cannula inserted into one common carotid artery permitted retrodrainage of blood reaching the circle of Willis via anastomotic channels. The blood from the cerebral vessels was washed out with dextran solution for photographic recording of the arrest of cerebral blood flow and subsequent reperfusion of the cerebral vasculature. Electroencephalographic, cardiovascular and respiratory functions were monitored throughout the procedure. Occlusion of the four major vessels with retrodrainage of the circle of Willis effectively stops perfusion of the brain. Occlusion of the vessels without retrodrainage permits a slow but significant flow of blood to the cerebral vessels. Rapid and effective reperfusion of the brain was noted even after repeated and lengthy periods of ischaemia. Thus a model for studying cerebral ischaemia, and reperfusion after ischaemia, without major thoracic or intracranial intervention is demonstrated. Some implications for resuscitation in cases of cerebral ischaemia are discussed.

The isolation and transplantation of the brain. An historical perspective emphasizing the surgical solutions to the design of these classical models

Following an historical review of earlier attempts to develop separated head and brain preparations and their contributions to modern-day understanding of the neurophysiology and neurochemistry of the central nervous system, the experiments that eventually led to the first successful total isolation of the mammalian brain are presented. The operative strategies emphasizing the anatomical and physiological problems requiring solution that resulted in vascular and neurogenic separation from the parent body and cephalon are described. The innovative engineering concepts that were utilized in the design of miniaturized equipment to maintain the isolated brain in a living state under conditions of cross circulation, extracorporeal artificial perfusion and transplantation are elaborated. Investigations employing isolated brain and cephalic preparation documenting tissue substrate requirements, metabolic and rheological conditions prevailing at various low temperatures and the immunologically privileged state of the separated organ are briefly presented. The unique opportunities these isolated brain models offer for study are emphasized as well as the complexity of their surgical preparation, which, to date, has limited their universal applications.

Extracorporeal perfusion of dog and monkey brain during circulatory arrest

Abstract Cerebral viability (as evidenced by the persistence of EEG activity) has been maintained in situ for many hours by utilizing simplified extracorporeal (pump-oxygenator) perfusion systems to provide cephalo-cerebral circulation, in cardiac-arrested canine and monkey preparations. Additional studies using unicarotid mechanical perfusion and EEG monitoring demonstrated the limitations at present characterizing the pumping elements utilized in isolated cerebral perfusion.