Brain oxygen balance under various experimental pathophysiologycal conditions.

Normally, brain tissue copes with negative oxygen balance by increasing cerebral blood flow (CBF). We examined the effects of increasing oxygen demand, by inducing spreading depression (SD) under various oxygen balance states, on brain O2 balance. The Tissue Vitality Monitoring System was used, which enables real time simultaneous in vivo monitoring of CBF, mitochondrial NADH and tissue HbO2 from the same region of the cerebral cortex.

Effects of anesthesia on brain mitochondrial function, blood flow, ionic and electrical activity monitored in vivo.

Thiopental, a well-known barbiturate, is often used in patients who are at high risk of developing cerebral ischemia, especially during brain surgery. Although barbiturates are known to affect a variety of processes in the cerebral cortex, including oxygen consumption by the mitochondria, the interrelation between mitochondrial function and anesthetics has not been investigated in detail under in vivo conditions. The aim of this study was to examine the effects of thiopental on brain functions in normoxia and under partial or complete ischemia.

Renal viability evaluated by the multiprobe assembly: a unique tool for the assessment of renal ischemic injury.

Background: One of the major causes of transplanted organs' dysfunction is ischemia-reperfusion injury, where mitochondrial dysfunction is the primary contributor to cell damage. Mitochondrial NADH fluorescence reliably describes intracellular oxygen deficiency and mitochondrial function. Therefore, its monitoring at the tissue level, together with other physiological parameters, can serve to evaluate tissue vitality.

Can the "brain-sparing effect" be detected in a small-animal model?

Background: Under O(2) imbalance in the body, blood redistribution occurs between more vital organs and less vital organs. This response is defined as the "brain-sparing effect". The study's aim was to develop a new rat model for simultaneous real-time monitoring of tissue viability in a highly vital organ, the brain, and a less vital organ, the small intestine, under various metabolic perturbations and emergency-like situations.

Effect of hyperbaric oxygenation on brain hemodynamics, hemoglobin oxygenation and mitochondrial NADH.

To determine the HbO(2) oxygenation level at the microcirculation, we used the hyperbaric chamber. The effects of hyperbaric oxygenation (HBO) were tested on vitality parameters in the brain at various pressures. Microcirculatory hemoglobin oxygen saturation (HbO(2)), cerebral blood flow (CBF) and mitochondrial NADH redox state were assessed in the brain of awake restrained rats using a fiber optic probe.

Effects of anesthesia on the responses to cortical spreading depression in the rat brain in vivo.

Objectives: The aim of this study was to evaluate the effect of cortical spreading depression (CSD) on the metabolic, hemodynamic, electrical and ionic properties during anesthesia as compared with the awake state.

Methods: The mitochondrial NADH redox state, reflected light, direct current (DC) potential, electrocorticography (ECoG), cerebral blood flow (CBF) and volume (CBV), and extracellular K(+) concentrations ([K(+)](e)), were measured continuously and simultaneously in real time using two unique monitoring systems that evaluate brain function. Three consecutive CSD waves were initiated using a KCl solution in both awake and anesthetized rats.

Effect of hypothermia on brain multi-parametric activities in normoxic and partially ischemic rats.

Hypothermia, as well as anesthesia, are known to protect the brain against ischemia, hypoxia and other pathological damages. One of the mechanisms of this improvement could be by lowering brain function, and thereby lowering oxygen demand. We examined the effect of hypothermia on brain function and blood supply in awake and anesthetized rats and studied the interaction between partial ischemia and the responses to hypothermia.