Left ventricular oxygen utilization efficiency is impaired in chronic streptozotocin-diabetic sheep

Now that oxygen production facilities can be controlled to match the requirements of the dissolution system, improved oxygen dissolution control can result in significant cost savings for oxygen activated sludge plants. This paper examines the potential cost savings of the vacuum exhaust control (VEC) strategy for the City of Houston, Texas 69th Street Treatment Complex. The VEC strategy involves operating a closed-tank reactor slightly below atmospheric pressure and using an exhaust apparatus to remove gas from the last stage of the reactor. Computer simulations for one carbonaceous reactor at the 69th Street Complex are presented for the VEC and conventional control strategies. At 80% of design loading the VEC strategy was found to provide an oxygen utilization efficiency of 94.9% as compared to 77.0% for the conventional control method. At design capacity the oxygen utilization efficiency for VEC and conventional control was found to be 92.3% and 79.5%, respectively. Based on the expected turn-down capability of Houston's oxygen production faciilities, the simulations indicate that the VEC strategy will more than double the possible cost savings of the conventional control method.

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Fasting promotes acute hypoxic adaptation by suppressing mTOR-mediated pathways

Cell Death and Disease ◽

10.1038/s41419-021-04351-x ◽

2021 ◽

Vol 12 (11) ◽

Author(s):

Ruzhou Zhao ◽

Xingcheng Zhao ◽

Xiaobo Wang ◽

Yanqi Liu ◽

Jie Yang ◽

...

Keyword(s):

Acute Hypoxia ◽

Survival Rates ◽

The Body ◽

Utilization Efficiency ◽

Ros Generation ◽

Oxygen Utilization ◽

Mtor Inhibition ◽

Atp Production ◽

Hypoxic Adaptation ◽

Hypoxic Tolerance

AbstractRapid adaptation to a hypoxic environment is an unanswered question that we are committed to exploring. At present, there is no suitable strategy to achieve rapid hypoxic adaptation. Here, we demonstrate that fasting preconditioning for 72 h reduces tissue injuries and maintains cardiac function, consequently significantly improving the survival rates of rats under extreme hypoxia, and this strategy can be used for rapid hypoxic adaptation. Mechanistically, fasting reduces blood glucose and further suppresses tissue mTOR activity. On the one hand, fasting-induced mTOR inhibition reduces unnecessary ATP consumption and increases ATP reserves under acute hypoxia as a result of decreased protein synthesis and lipogenesis; on the other hand, fasting-induced mTOR inhibition improves mitochondrial oxygen utilization efficiency to ensure ATP production under acute hypoxia, which is due to the significant decrease in ROS generation induced by enhanced mitophagy. Our findings highlight the important role of mTOR in acute hypoxic adaptation, and targeted regulation of mTOR could be a new strategy to improve acute hypoxic tolerance in the body.

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Improved exercise capacity in cyclophilin‐D knockout mice associated with enhanced oxygen utilization efficiency and augmented glucose uptake via AMPK‐TBC1D1 signaling nexus

The FASEB Journal ◽

10.1096/fj.201802238r ◽

2019 ◽

Vol 33 (10) ◽

pp. 11443-11457 ◽

Cited By ~ 2

Author(s):

Jeejabai Radhakrishnan ◽

Alvin Baetiong ◽

Harrison Kaufman ◽

Michelle Huynh ◽

Angela Leschinsky ◽

...

Keyword(s):

Glucose Uptake ◽

Exercise Capacity ◽

Knockout Mice ◽

Utilization Efficiency ◽

Cyclophilin D ◽

Oxygen Utilization

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Increased in blood flow to ischemic myocardium caused by a new dopamine analog

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1978.235.2.h118 ◽

1978 ◽

Vol 235 (2) ◽

pp. H118-H130

Author(s):

J. N. Diana ◽

B. C. Brenton ◽

J. P. Long ◽

J. G. Cannon ◽

M. H. Laughlin ◽

...

Keyword(s):

Blood Flow ◽

Venous Pressure ◽

Left Ventricular ◽

Control Flow ◽

Ventricular Free Wall ◽

Normal Myocardium ◽

Free Wall ◽

Oxygen Utilization ◽

Right Ventricular Free Wall ◽

Coronary Vasodilator

In the anesthetized, open-chest dog, intravenous infusion 8– 13 microgram . kg-1. min-1) of a new dopamine analog 5,6-dihydroxy-2-methylaminotetralin hydrobromide (M-8) demonstrated potent coronary vasodilator properties. Blood flow to normal myocardium was increased an average of 53% above control flow values and this was associated with a decrease in coronary vascular resistance of 50%. The increase in blood flow was distributed uniformly to all portions of the myocardium (left ventricular free wall, right ventricular free wall, and septum). Subendocardial/subepicardial (endo/epi) flow ratios of the left ventricle, right ventricle, and septum were not significantly changed from control. In dog hearts subjected to acute, sudden occlusion of portions of the left anterior branch of the left coronary artery, M-8 produced a 93% increase in flow to the whole heart over postocclusion flow values. Flow to tissues of the heart made ischemic by the occlusive procedure in creased by an average of 94% during M-8 administration despite the fact that the occlusive ligatures remained in place. The vasodilation produced by M-8 was accompanied by a 22–24% increase in myocardial capillary surface area available for exchange of lipid-insoluble substances, fructose and sucrose. Hemodynamic changes associated with M-8 include a transient decrease in aortic pressure, but no change in heart rate, left ventricular (dP/dt)/P, or central venous pressure. Propranolol blocked the vasodilator activity of M-8. It was concluded that M-8 is a beta2-adrenergic receptor agonist having potent coronary vasodilator properties which also has the ability to open preexisting collateral blood flow channels and provide nutritive flow to ischemic, marginally ischemic, and normal myocardium. The cardiovascular actions of M-8 increase blood flow and oxygen delivery to the myocardium while decreasing the work and oxygen utilization by the heart, suggesting that it may have important antianginal characteristics.

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Recovery of oxygen utilization efficiency after global myocardial ischemia

The Annals of Thoracic Surgery ◽

10.1016/0003-4975(91)91283-2 ◽

1991 ◽

Vol 52 (5) ◽

pp. 1063-1068 ◽

Cited By ~ 12

Author(s):

Satoshi Furukawa ◽

Gerhard Kreiner ◽

Joseph E. Bavaria ◽

James T. Streicher ◽

L.Henry Edmunds

Keyword(s):

Myocardial Ischemia ◽

Utilization Efficiency ◽

Oxygen Utilization

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Hyperlipidemia with Hypoglycemia Reduces Myocardial Oxygen Utilization Efficiency but not Contractile Function During Coronary Hypoperfusion

Journal of Molecular and Cellular Cardiology ◽

10.1006/jmcc.2000.1190 ◽

2000 ◽

Vol 32 (8) ◽

pp. 1539-1552 ◽

Cited By ~ 2

Author(s):

Bradley J Hart ◽

Xiaoming Bian ◽

Robert T Mallet ◽

H Fred Downey

Keyword(s):

Contractile Function ◽

Utilization Efficiency ◽

Oxygen Utilization

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Predictable reduction in left ventricular stroke work and oxygen utilization with an implantable centrifugal pump

The Annals of Thoracic Surgery ◽

10.1016/0003-4975(94)90447-2 ◽

1994 ◽

Vol 58 (4) ◽

pp. 1018-1024 ◽

Cited By ~ 18

Author(s):

Andrew H. Goldstein ◽

John J. Pacella ◽

Richard E. Clark

Keyword(s):

Centrifugal Pump ◽

Left Ventricular ◽

Stroke Work ◽

Oxygen Utilization

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Heart size and maximal cardiac output are limited by the pericardium

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1992.263.6.h1675 ◽

1992 ◽

Vol 263 (6) ◽

pp. H1675-H1681 ◽

Cited By ~ 16

Author(s):

H. K. Hammond ◽

F. C. White ◽

V. Bhargava ◽

R. Shabetai

Keyword(s):

Cardiac Output ◽

Oxygen Consumption ◽

Diastolic Pressure ◽

Maximal Oxygen Consumption ◽

Left Ventricular ◽

Treadmill Running ◽

Oxygen Utilization ◽

End Diastolic Volume ◽

Maximal Cardiac Output ◽

Heart Size

We tested the hypothesis that the pericardium, by restricting heart size, limits maximal cardiac output and oxygen consumption. We studied 15 pigs. Five underwent maximal treadmill running before and 14–21 days after thoracotomy and pericardiectomy; these pigs also received sequential volume infusions to determine end-diastolic pressure-dimension relationships. Five underwent maximal treadmill running before and 14–21 days after thoracotomy (pericardium undisturbed) to determine the effect of thoracotomy on exercise performance. Finally, five underwent thoracotomy, instrumentation, loose closure of the pericardium, and sequential volume infusions to determine the effect of thoracotomy without pericardiectomy on end-diastolic pressure-dimension relationships. Pericardiectomy caused similar increases in maximal cardiac output (29% increase; P = 0.007) and maximal oxygen consumption (31% increase; P = 0.02). These results were associated with increased left ventricular end-diastolic dimension (10% increase; P = 0.01) and an estimated 33% increase in end-diastolic volume. In addition, left ventricular mass was increased by pericardiectomy (18% increase; P < 0.04). Thus the pericardium, by limiting utilization of the Starling mechanism, limits maximal cardiac output, and the limit to cardiorespiratory performance lies not in oxygen utilization, but in oxygen delivery. Furthermore, removal of pericardium is associated with myocardial hypertrophy.

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