Tissue Oxygen Demand in Regulation of the Behavior of the Cells in the Vasculature

2013 ◽  
Vol 20 (6) ◽  
pp. 484-501 ◽  
Author(s):  
Nadezhda N. Barvitenko ◽  
Muhammad Aslam ◽  
Jessica Filosa ◽  
Elena Matteucci ◽  
Mikko Nikinmaa ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Tissue Oxygen

Respiratory alkalosis increases tissue oxygen demand

1979 ◽  
Vol 26 (6) ◽  
pp. 687-692 ◽  
Author(s):  
Hassan Rastegar ◽  
Monty Woods ◽  
Alden H. Harken
Keyword(s):  
Oxygen Demand ◽  
Respiratory Alkalosis ◽  
Tissue Oxygen

Apparent diffusion time of oxygen from blood to tissue in rat cerebral cortex: implication for tissue oxygen dynamics during brain functions

2007 ◽  
Vol 103 (4) ◽  
pp. 1352-1358 ◽  
Author(s):  
Kazuto Masamoto ◽  
Jeff Kershaw ◽  
Masakatsu Ureshi ◽  
Naosada Takizawa ◽  
Hirosuke Kobayashi ◽  
...  
Keyword(s):  
Time Course ◽  
Oxygen Demand ◽  
Excess Demand ◽  
Tissue Oxygen ◽  
Doppler Flowmetry ◽  
Demand And Supply ◽  
Brain Functions ◽  
Apparent Diffusion ◽  
Time Required ◽  
Stimulus Length

To investigate the dynamics of tissue oxygen demand and supply during brain functions, we simultaneously recorded Po2 and local cerebral blood flow (LCBF) with an oxygen microelectrode and laser Doppler flowmetry, respectively, in rat somatosensory cortex. Electrical hindlimb stimuli were applied for 1, 2, and 5 s to vary the duration of evoked cerebral metabolic rate of oxygen (CMRO2). The electrical stimulation induced a robust increase in Po2 (4–9 Torr at peak) after an increase in LCBF (14–26% at peak). A consistent lag of ∼1.2 s (0.6–2.3 s for individual animals) in the Po2 relative to LCBF was found, irrespective of stimulus length. It is argued that the lag in Po2 was predominantly caused by the time required for oxygen to diffuse through tissue. During brain functions, the supply of fresh oxygen further lagged because of the latency of LCBF onset (∼0.4 s). The results indicate that the tissue oxygen supports excess demand until the arrival of fresh oxygen. However, a large drop in Po2 was not observed, indicating that the evoked neural activity demands little extra oxygen or that the time course of excess demand is as slow as the increase in supply. Thus the dynamics of Po2 during brain functions predominantly depend on the time course of LCBF. Possible factors influencing the lag between demand and supply are discussed, including vascular spacing, reactivity of the vessels, and diffusivity of oxygen.

scholarly journals Theoretical predictions of metabolic flow regulation in the retina

2016 ◽  
Vol 1 (2) ◽  
pp. 70-78
Author(s):  
Simone Cassani ◽  
Julia Arciero ◽  
Giovanna Guidoboni ◽  
Brent Siesky ◽  
Alon Harris
Keyword(s):  
Blood Flow ◽  
Oxygen Demand ◽  
Flow Regulation ◽  
Retinal Blood Flow ◽  
Regulatory Mechanisms ◽  
Tissue Oxygen ◽  
Theoretical Predictions ◽  
Health And Disease ◽  
Experimental Findings ◽  
Different Levels

Purpose: This study uses a theoretical model to investigate the response of retinal blood flow to changes in tissue oxygen demand. The study is motivated by the need for a better understanding of metabolic flow regulation mechanisms in health and disease.Methods: A mathematical model is used to calculate retinal blood flow for different levels of tissue oxygen demand in the presence or absence of regulatory mechanisms. The model combines a compartmental view of the retinal vasculature and a Krogh cylinder description for oxygen delivery to retinal tissue.Results: The model predicts asymmetric behavior in response to changes in tissue oxygen demand. When all regulatory mechanisms are active, the model predicts a 6% decrease in perfusion when tissue oxygen demand is decreased by 50% and a 23% increase in perfusion when tissue oxygen demand is increased by 50%. In the absence of metabolic and carbon dioxide responses, the model predicts a constant level of blood flow that does not respond to changes in oxygen demand, suggesting the importance of these two response mechanisms. The model is not able to replicate the increase in oxygen venous saturation that has been observed in some flicker stimulation studies.Conclusions: The increase in blood flow predicted by the model due to an increase in oxygen demand is not in the same proportion as the change in blood flow observed with the same decrease in oxygen demand, suggesting that vascular regulatory mechanisms may respond differently to different levels of oxygen demand. These results might be useful for interpreting clinical and experimental findings in health and disease.

scholarly journals Potential Relationship between Cerebral Fractional Tissue Oxygen Extraction (FTOE) and the Use of Sedative Agents during the Perioperative Period in Neonates and Infants

Children ◽  
2020 ◽  
Vol 7 (11) ◽  
pp. 209
Author(s):  
Danguolė Č Rugytė ◽  
Loreta Strumylaitė
Keyword(s):  
Quantile Regression ◽  
Near Infrared ◽  
Total Duration ◽  
Oxygen Demand ◽  
Oxygen Extraction ◽  
Tissue Oxygen ◽  
Arterial Blood ◽  
The Mean ◽  
Neonates And Infants ◽  
Sedative Agents

Fractional tissue oxygen extraction (FTOE) by means of cerebral near-infrared spectroscopy (NIRS) provides information about oxygen uptake in the brain. Experimental animal data suggest that sedative agents decrease cerebral oxygen demand. The aim of the present study was to investigate the association between the cerebral FTOE and the use of pre and intraoperative sedative agents in infants aged 1–90 days. Cerebral NIRS was continuously applied during open major non-cardiac surgery in 46 infants. The main outcomes were the mean intraoperative FTOE and the percentage (%) of time of intraoperative hyperoxiaFTOE relative to the total duration of anesthesia. HyperoxiaFTOE was defined as FTOE ≤ 0.1. Cumulative doses of sedative agents (benzodiazepines and morphine), given up to 24 h preoperatively, correlated with the mean intraoperative FTOE (Spearman’s rho = −0.298, p = 0.0440) and were predictive for the % of time of intraoperative hyperoxiaFTOE (β (95% CI) 47.12 (7.32; 86.92)) when adjusted for the patients’ age, type of surgery, preoperative hemoglobin, intraoperative sevoflurane and fentanyl dose, mean intraoperative arterial blood pressure, and end-tidal CO2 by multivariate 0.75 quantile regression. There was no association with 0.5 quantile regression. We observed the suggestive positive association of decreased fractional cerebral tissue oxygen extraction and the use of sedative agents in neonates and infants undergoing surgery.

Postnatal regulation of oxygen delivery: hematologic parameters of postnatal dogs

1979 ◽  
Vol 237 (1) ◽  
pp. H71-H75 ◽  
Author(s):  
P. A. Mueggler ◽  
J. S. Peterson ◽  
R. D. Koler ◽  
J. Metcalfe ◽  
J. A. Black
Keyword(s):  
Oxygen Delivery ◽  
Cell Mass ◽  
Oxygen Affinity ◽  
Oxygen Demand ◽  
Hemoglobin Concentration ◽  
Postnatal Life ◽  
Red Cell ◽  
Tissue Oxygen ◽  
Red Cell Mass ◽  
Tissue Oxygen Delivery

Hematologic parameters influencing tissue oxygen delivery in dogs during the first 4 mo of life have been investigated. The rapid growth and increase in body temperature during this period imply an increased metabolic rate and increased tissue oxygen demand. Hemoglobin concentration and hematocrit decrease during the 1st mo following birth. The total red cell mass does not decrease during this period. The observed hemodilution can be attributed to an increasing plasma volume in the growing animal. The blood oxygen affinity decreases during this same period, resulting in a more effective tissue oxygen delivery. Erythropoiesis, as estimated from the percent circulating reticulocytes, decreases following birth and does not increase until 1 mo of postnatal life. The increase of erythropoietic activity during the 2nd mo of postnatal life coincides with an increase in red cell mass, hematocrit, and hemoglobin concentration.

scholarly journals GBT440 inhibits sickling of sickle cell trait blood under in vitro conditions mimicking strenuous exercise

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Kobina Dufu ◽  
Josh Lehrer-Graiwer ◽  
Eleanor Ramos ◽  
Donna Oksenberg
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Trait ◽  
Oxygen Demand ◽  
Physical Activities ◽  
Strenuous Exercise ◽  
Cell Disease ◽  
Tissue Oxygen ◽  
Benign Condition ◽  
Life Threatening

In sickle cell trait (SCT), hemoglobin A (HbA) and S (HbS) are co-expressed in each red blood cell (RBC). While homozygous expression of HbS (HbSS) leads to polymerization and sickling of RBCs resulting in sickle cell disease (SCD) characterized by hemolytic anemia, painful vaso-occlusive episodes and shortened life-span, SCT is considered a benign condition usually with minor or no complications related to sickling. However, physical activities that cause increased tissue oxygen demand, dehydration and/or metabolic acidosis leads to increased HbS polymerization and life-threatening complications including death. We report that GBT440, an agent being developed for the treatment of SCD, increases the affinity of oxygen for Hb and inhibits in vitro polymerization of a mixture of HbS and HbA that simulates SCT blood. Moreover, GBT440 prevents sickling of SCT blood under in vitro conditions mimicking strenuous exercise with hypoxia, dehydration and acidosis. Together, our results indicate that GBT440 may have the potential to protect SCT individuals from sickling-related complications during conditions that favor HbS polymerization.

DECOLOURIZATION AND COD REMOVAL OF WASEWATER FROM ETHANOL PRODUCTION PROCESS FROM MOLASSES BY COAGULANTION USING INORGANIC ALUM

2010 ◽  
Vol 13 (3) ◽  
pp. 92-102
Author(s):  
Trung Duc Le
Keyword(s):  
Ethanol Production ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Treatment Processes ◽  
Physico Chemical ◽  
Biological Methods ◽  
Treatment Step ◽  
Main Material

The industrial production of ethanol by fermentation using molasses as main material that generates large quantity of wastewater. This wastewater contains high levels of colour and chemical oxygen demand (COD), that may causes serious environmental pollution. Most available treatment processes in Vietnam rely on biological methods, which often fail to treat waste water up to discharge standard. As always, it was reported that quality of treated wastewater could not meet Vietnameses discharge standard. So, it is necessary to improve the treatment efficiency of whole technological process and therefore, supplemental physico-chemical treatment step before biodegradation stage should be the appropriate choice. This study was carried out to assess the effect of coagulation process on decolourization and COD removal in molasses-based ethanol production wastewater using inorganic coaglutant under laboratory conditions. The experimental results showed that the reductions of COD and colour with the utilization of Al2(SO4)3 at pH 9.5 were 83% and 70%, respectively. Mixture FeSO4 – Al2(SO4)3 at pH 8.5 reduced 82% of colour and 70% of COD. With the addition of Polyacrylamide (PAM), the reduction efficiencies of colour, COD and turbidity by FeSO4 – Al2(SO4)3 were 87%, 73.1% and 94.1% correspondingly. It was indicated that PAM significantly reduced the turbidity of wastewater, however it virtually did not increase the efficiencies of colour and COD reduction. Furthermore, the coagulation processes using PAM usually produces a mount of sludge which is hard to be deposited.

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