scholarly journals Oxygen Consumption of the Isolated Heart of Octopus: Effects of Power Output and Hypoxia

1987 ◽  
Vol 131 (1) ◽  
pp. 137-157
Author(s):  
D. F. HOULIHAN ◽  
C. AGNISOLA ◽  
N. M. HAMILTON ◽  
I. TRARA GENOINO
Keyword(s):  
Oxygen Consumption ◽  
Output Power ◽  
Power Output ◽  
Isolated Heart ◽  
Back Pressure ◽  
Octopus Vulgaris ◽  
Total Oxygen ◽  
Coronary Veins ◽  
Output Flow

A technique is described which allowed the measurement of the oxygen consumption of the isolated heart of Octopus vulgaris. Contraction of the heart resulted in an aortic output and a flow through the heart muscle into coronary veins (the coronary output). The flow and oxygen content of the aortic output and the coronary output were measured with variable input pressures and constant output back pressure (volume loaded), variable output back pressure and constant aortic output (pressure loaded), and during hypoxia. Volume loading of the heart resulted in an increase in aortic output, power output and total oxygen consumption. Pressure loading increased power output and total oxygen consumption of the heart. Exposure to hypoxia decreased the aortic output, power output and total cardiac oxygen consumption. In the response of the heart to reduced work, brought about either by a reduced input pressure or by hypoxic perfusate, the power output was linearly related to the total oxygen consumption of the heart. The oxygen extracted from the coronary output accounted for 80–100% of the total oxygen consumption of the heart. Coronary output amounted to 30% of the total cardiac output at maximum power output. In volume-loaded hearts the volume of the coronary output increased as aortic output increased; in pressure-loaded hearts coronary output increased as power output increased, but aortic output remained constant. In hypoxia, the coronary output increased as the aortic output fell. At a perfusate Po2 of around 50 Torr (1 Torr = 133 Pa), the aortic output ceased although the heart continued to beat and the coronary output continued, accounting for all of the oxygen consumption of the heart. The coronary output flow in vitro therefore has the capacity to be varied independently of the aortic output flow to maintain the oxygen supply to the perfused cardiac muscle.

scholarly journals OXYGEN SUPPLY AND IN VITRO PERFORMANCE OF THE SYSTEMIC HEART OF OCTOPUS VULGARIS: EFFECTS OF HAEMOCYANIN

1991 ◽  
Vol 157 (1) ◽  
pp. 523-540 ◽  
Author(s):  
C. AGNISOLA ◽  
D. F. HOULIHAN
Keyword(s):  
Oxygen Consumption ◽  
Stroke Volume ◽  
Oxygen Supply ◽  
Sea Water ◽  
Isolated Heart ◽  
Carbon Dioxide Production ◽  
Octopus Vulgaris ◽  
Systemic Heart

The effect of increasing oxygen supply on the perfused systemic heart of Octopus vulgaris (Lam.) by using oxygenated or haemocyanin-containing perfusates was investigated. Providing aerated blood or seawater solutions of haemocyanin that were comparable with blood in oxygen-carrying capacity improved the performance of the isolated heart compared with that of hearts perfused with aerated sea water. Aortic outputs were similar to in vivo values (44ml min−1 g−1) at close to in vivo values of preload and afterload owing to an increase in both heart rate (from 24.0 to 38.4beatsmin−1) and stroke volume (from 0.69 to 1.10ml g−1). Coronary flow fell in these conditions, becoming 2.5% of the aortic output (against 24% with aerated sea water). A parallel increase in coronary resistance was found. Oxygenated sea water also improved the performance of the heart, mainly by improving the stroke volume. Both with haemocyanin solutions or blood and with oxygenated sea water, the isolated heart was able to do more work at lower preloads compared with the hearts perfused with aerated sea water. Power output was linearly related to total oxygen consumption and carbon dioxide production. The major site of oxygen consumption was the coronary bed. Haemocyanin released about 70% of the bound oxygen as it passed through the ventricular wall. Note: Present address: Department of Zoology, University of Aberdeen, Aberdeen AB9 2TN, Scotland, UK.

Cutaneous respiration in Octopus vulgaris

1996 ◽  
Vol 199 (11) ◽  
pp. 2477-2483 ◽  
Author(s):  
J Wells
Keyword(s):  
Boundary Layer ◽  
Blood System ◽  
Octopus Vulgaris ◽  
Oxygen Requirement ◽  
Total Oxygen ◽  
Entire Surface ◽  
Skin Sample ◽  
Cutaneous Respiration

The skin of Octopus vulgaris consumes considerable quantities of oxygen in vitro, averaging 4.55x10(-5)±1.80x10(-5) ml mm-2 h-1 (mean ± s.d.), if a flow is maintained over the skin sample (N=32). The consumption is higher still in vivo, 11.36x10(-5)±2.73x10(-5) ml mm-2 h-1 (N=8), suggesting an additional net import of oxygen through the skin when the blood system is intact. If a substantial boundary layer is allowed to develop, oxygen uptake in vitro falls to 2.09x10(-5)±0.56x10(-5) ml mm-2 h-1 (N=15). The proportion of the animals' total oxygen consumption that cutaneous uptake will represent must thus depend on how much of the skin is exposed and how well it is ventilated. Estimates indicate that some 41 % of the total oxygen requirement of an animal at rest might be satisfied in this manner. During exercise, with water flowing over the entire surface of the animal, cutaneous uptake will increase but is nevertheless likely to form a smaller proportion (about 33 %) of the total uptake. In an animal curled up in its den and digesting a substantial meal, cutaneous uptake could shrink to as little as 3 % of the total. Similar results were obtained in a small number of pilot experiments with a range of octopod, sepioid and teuthoid species.

scholarly journals INTRAVASCULAR HEMAGGLUTINATION

Blood ◽  
1950 ◽  
Vol 5 (12) ◽  
pp. 1114-1124 ◽  
Author(s):  
RICHARD DAY ◽  
ELISE PERRY
Keyword(s):  
Oxygen Consumption ◽  
Hemolytic Anemia ◽  
Sedimentation Rate ◽  
The Other ◽  
Red Cell ◽  
Tissue Oxygen ◽  
Total Oxygen ◽  
Cell Agglutination ◽  
Additional Support

Abstract Severe degrees of intravascular red cell agglutination have been observed during life in rats injected with anti-rat red cell serum and in a patient of 11 months with chronic acquired hemolytic anemia. There was no significant fall in the tissue oxygen tension or in the total oxygen consumption of the rats. Neither the rats nor the infant developed kernicterus. In a baby dying with kernicterus no true hemagglutination was observed, although there was slight sludging such as is seen in many illnesses. Additional support for the belief that the red cells in this case were not clumped lies in the fact that in vitro clumping was not observed; furthermore, the sedimentation rate was only 1 mm. in one hour. The blood of the injected rats and of the other infant who did not develop kernicterus sedimented extremely rapidly and displayed spontaneous agglutination in vitro. These observations indicate that intravascular agglutination has little if any bearing on the development of kernicterus in erythroblastosis fetalis.

Protein synthesis in a fish heart: responses to increased power output

1988 ◽  
Vol 137 (1) ◽  
pp. 565-587 ◽  
Author(s):  
D. F. Houlihan ◽  
C. Agnisola ◽  
A. R. Lyndon ◽  
C. Gray ◽  
N. M. Hamilton
Keyword(s):  
Protein Synthesis ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Power Output ◽  
Coronary Vessels ◽  
High Concentration ◽  
Fish Heart ◽  
Bulbus Arteriosus

The effects of exercise on the rates of protein synthesis in the chambers of the trout heart were investigated in vitro and in vivo. An in vitro rainbow trout heart preparation was developed which permitted perfusion of the coronary supply to the compact region of the ventricular muscle. This preparation was used to examine the mechanical responses to preload pressures, the oxygen consumption at different power outputs and the rates of protein synthesis in the various heart components. By increasing preload pressure it was possible to double cardiac output, oxygen consumption and power output without changing heart rate. Mechanical efficiency of the hearts was approximately 20%. Perfusion of the coronary vessels improved cardiac output. Protein synthesis was measured in isolated hearts by the incorporation of [3H]phenylalanine added at high concentration (1.35 mmol l-1) to the perfusion medium. The various chambers of the heart showed marked differences in their rates of protein synthesis. Increasing cardiac output and power output in vitro by twofold over 20 min increased the fractional rate of protein synthesis by approximately 2.5-fold in the atrium and ventricle but did not affect the rates in the bulbus arteriosus. Perfusion of the coronary vessels significantly increased the rates of protein synthesis of the compact layer of the ventricle. In vivo there were no significant differences in the fractional protein synthesis rates between the atrium and ventricle; slow-speed continuous swimming over 40 min (1.5 body lengths s-1) caused an increase in the rates of protein synthesis in all the chambers except the bulbus arteriosus. The stimulation in the fractional rates of protein synthesis by approximately 32% was not as great as in vitro. Both in vivo and in vitro the increased rates of protein synthesis occurred without any change in RNA to protein ratios, indicating an improved activity of protein synthesis per unit of RNA. It is concluded that short-term increases in cardiac contractility, possibly acting through the mechanical stretch on the cardiac muscle, stimulated protein synthesis, particularly in the ventricle, through increased ribosomal activity.

scholarly journals Myocardial Oxygen Consumption and Lactate Release by the Hypoxic Hagfish Heart

1991 ◽  
Vol 156 (1) ◽  
pp. 583-590 ◽  
Author(s):  
M. E. FORSTER
Keyword(s):  
Oxygen Consumption ◽  
Energy Demand ◽  
Myocardial Oxygen Consumption ◽  
Isolated Heart ◽  
Regression Line ◽  
Maximal Power Output ◽  
Wide Range ◽  
Consumption Rates ◽  
Rate Of Oxygen Consumption

Myocardial oxygen consumption (MOO2)and lactic acid release were measured in the isolated heart of a hagfish (Eptatretus cirrhatus Forster) perfused in vitro. Two different ranges of partial pressures of oxygen were employed (PIOO2 3.87-5.87 and 1.60-2.67 kPa). All hearts released lactate into the perfusate, but the rate of release was greater and MOO2 was depressed at the lower PIOO2. When energy production through the glycolytic pathway to lactate is converted to oxygen equivalents and added to measured oxygen consumption rates, over a wide range of power outputs and different values of POO2, the data can be fitted to a single linear regression line. The rate of oxygen consumption of the hagfish myocardium, so obtained, is similar to values reported for teleost fish. The unusual ability of the hagfish myocardium to support perhaps up to 50 + of its maximal power output through anaerobic metabolism is related to its extremely low cardiac energy demand.

Caffeine supplementation for 4-day, followed by acute ingestion, did not impact triathlete output power after submaximal intensity exercise

2019 ◽  
Vol 18 (3) ◽  
pp. 118
Author(s):  
Anderson Pontes Morales ◽  
Felipe Sampaio-Jorge ◽  
Thiago Barth ◽  
Alessandra Alegre De Matos ◽  
Luiz Felipe Da Cruz Rangel ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Output Power ◽  
Body Mass ◽  
Effect Size ◽  
Power Output ◽  
Anaerobic Power ◽  
Lactate Concentration ◽  
Wingate Test ◽  
Large Effect Size ◽  
Acute Ingestion

Introduction: The aim of this study was to test the hypothesis that caffeine supplementation (6 mg·kg-1 body mass) for 4-days, followed by acute intake, would impact five male triathletes output power after performed submaximal intensity exercise. Methods: This was a randomized, double-blind, placebo-controlled crossover study, placebo (4-day) - placebo (acute) PP, placebo (4-days) -caffeine (acute) PC, and caffeine (4-day) - caffeine (acute) CC. Participants abstained from dietary caffeine sources for 4 days and ingested capsules containing either placebo or caffeine (6 mg.kg-1 body mass day in one absorption). The acute trials the capsules containing placebo or caffeine (6 mg.kg-1 body mass day in one absorption) were ingested 60min before completing exercise in a treadmill for 40min (80% VO2max) and to perform the Wingate test. Results: Blood lactate was determined before, 60min after ingestion, and immediately after the exercise on the treadmill, the Wingate test, and after the recovery (10-min). CC and PC trials did not change the cardiopulmonary variables (P>0.05) and the anaerobic power variables (peak/mean power output and fatigue index) (P>0.05). The PC trial compared with PP promoted improvements in the curve power output in 2 sec by 31.19% (large effect-size d = 1.08; P<0.05) and 3 sec by 20% (large effect-size d = 1.19; P<0.05). A 10min recovery was not sufficient to reduce blood lactate concentration in the PC trial compared with PP (PC, 13.73±2.66 vs. PP, 10.26±1.60 mmol.L-1; P<0.05, respectively) (P<0.05). Conclusion: In conclusion, these results indicate that caffeine supplementation (6 mg·kg-1 body mass) for 4 days, followed by acute ingestion, did not impact the triathletes output power after performed submaximal intensity exercise. Nutritional interventions may help researchers and athletes to adapt strategies for manipulating caffeine use.Key-words: caffeine metabolism, Wingate test, blood lactate, performance.

scholarly journals Analytical Modeling of a Doubly Clamped Flexible Piezoelectric Energy Harvester with Axial Excitation and Its Experimental Characterization

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3861
Author(s):  
Jie Mei ◽  
Qiong Fan ◽  
Lijie Li ◽  
Dingfang Chen ◽  
Lin Xu ◽  
...  
Keyword(s):  
Output Power ◽  
Power Output ◽  
Output Voltage ◽  
Energy Harvester ◽  
Load Resistance ◽  
Engineering Practice ◽  
Maximum Output ◽  
Widespread Application ◽  
Piezoelectric Energy ◽  
Axial Excitation

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.

scholarly journals Necrostatin-1 Supplementation to Islet Tissue Culture Enhances the In-Vitro Development and Graft Function of Young Porcine Islets

2021 ◽  
Vol 22 (16) ◽  
pp. 8367
Author(s):  
Hien Lau ◽  
Shiri Li ◽  
Nicole Corrales ◽  
Samuel Rodriguez ◽  
Mohammadreza Mohammadi ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Oxygen Consumption ◽  
Insulin Secretion ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
In Vitro Development ◽  
Porcine Islets ◽  
Vitro Development

Pre-weaned porcine islets (PPIs) represent an unlimited source for islet transplantation but are functionally immature. We previously showed that necrostatin-1 (Nec-1) immediately after islet isolation enhanced the in vitro development of PPIs. Here, we examined the impact of Nec-1 on the in vivo function of PPIs after transplantation in diabetic mice. PPIs were isolated from pancreata of 8–15-day-old, pre-weaned pigs and cultured in media alone, or supplemented with Nec-1 (100 µM) on day 0 or on day 3 of culture (n = 5 for each group). On day 7, islet recovery, viability, oxygen consumption rate, insulin content, cellular composition, insulin secretion capacity, and transplant outcomes were evaluated. While islet viability and oxygen consumption rate remained high throughout 7-day tissue culture, Nec-1 supplementation on day 3 significantly improved islet recovery, insulin content, endocrine composition, GLUT2 expression, differentiation potential, proliferation capacity of endocrine cells, and insulin secretion. Adding Nec-1 on day 3 of tissue culture enhanced the islet recovery, proportion of delta cells, beta-cell differentiation and proliferation, and stimulation index. In vivo, this leads to shorter times to normoglycemia, better glycemic control, and higher circulating insulin. Our findings identify the novel time-dependent effects of Nec-1 supplementation on porcine islet quantity and quality prior to transplantation.

scholarly journals Oxygen consumption in mouse skeletal muscles stimulated Na-permeability in vitro

1989 ◽  
Vol 49 ◽  
pp. 169
Author(s):  
Hideto Awano ◽  
Tetsuya Hasegawa ◽  
Masakazu Nishimura ◽  
Osamu Yagasaki ◽  
Katsuaki Ito
Keyword(s):  
Oxygen Consumption ◽  
Skeletal Muscles ◽  
Na Permeability
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