OBJECTIVES OBJECTIVES The effect of cortical spreading depression (CSD) on extracellular K(+) concentrations ([K(+)](e)), cerebral blood flow (CBF), mitochondrial NADH redox state and direct current (DC) potential was studied during normoxia and three pathological conditions: hypoxia, after NOS inhibition by L-NAME and partial ischemia. METHODS A SPECIAL DEVICE (MPA) WAS USED FOR MONITORIN...

We tested the hypothesis that residual oxygen supply during acute low-flow ischaemia or hypoxemia is a major regulator of myocardial performance, metabolism and recovery. Rat hearts were exposed for 20 min to either ischemia (coronary flow reduced to 10% of baseline), hypoxemia (oxygen content reduced to 10% baseline) or a "mixed" condition (combined ischaemia and hypoxemia). The oxygen supply ...

Background Oxygenation-sensitive (OS) imaging relies on alterations of deoxyhemoglobin (dHb) in the blood. Thus signal intensity (SI) is dependent on the factors that shift the dHb fraction; oxygen saturation, tissue oxygen extraction and blood supply. We aimed to physically measure and compare these parameters while manipulating myocardial oxygenation with systemic CO2 changes. These changes c...

This study describes a novel strategy to regulate the metabolic flux for lactic acid production in Lactobacillus casei. The ldhL gene encoding L-lactate dehydrogenase (L-LDH) was overexpressed in L. casei, and a two-stage oxygen supply strategy (TOS) that maintained a medium oxygen supply level during the early fermentation phase, and a low oxygen supply level in the later phase was carried out...

Coronary Artery Disease (CAD) is defined as obstruction of the lumen of the coronary artery due to formation of atherosclerotic plaque which contains cholesterol streaks. This eventually leads to reduced blood flow and blood supply to the myocardium. Patients having this problem will complain of chest pain on exertion due to reduction in the coronary perfusion which leads to a reduction in supp...

There is little data about the use of different oxygen sources during assessment for long-term oxygen therapy (LTOT) and how this impacts upon blood oxygen tensions and prescribed flow rates. Patients with chronic obstructive pulmonary disease (COPD), n=30, had assessments for LTOT using both an oxygen-concentrator and piped hospital oxygen (wall-oxygen) as supply sources. In addition, a random...

Besides acting as an oxygen store during times of reduced blood oxygen supply, myoglobin can also facilitate intracellular oxygen transport by diffusion of oxymyoglobin along a PO(2) gradient. We reassess the importance of myoglobin-facilitated oxygen diffusion by applying new findings on the intracellular diffusivity of myoglobin in a model calculation.

Hypoxia is defined as the reduction or lack of oxygen in organs, tissues, or cells. This decrease of oxygen tension can be due to a reduced supply in oxygen (causes include insufficient blood vessel network, defective blood vessel, and anemia) or to an increased consumption of oxygen relative to the supply (caused by a sudden higher cell proliferation rate). Hypoxia can be physiologic or pathol...

The effect of cortical spreading depression (CSD) on oxygen demand (extracellular K(+)), oxygen supply (cerebral blood flow - CBF) and oxygen balance (mitochondrial NADH) was studied by a special multiprobe assembly (MPA), during hypoxia and partial ischemia. The MPA was constructed and applied to monitor the CSD wave from its front line until complete recovery, continuously and simultaneously....

The role of light as an energy source for slightly aereated cultures of halobacteria was studied, using continuous cultures with low nutrient concentrations and a low oxygen supply. A series of experiments were carried out with non-illuminated and differently illuminated cultures and with different oxygen transfer rates. Under low oxygen availability, light proved to be a decisively important e...