Respiration of the Winnipeg Goldeye (Hiodon alosoides)

1968 ◽  
Vol 25 (12) ◽  
pp. 2603-2608 ◽  
Author(s):  
J. S. Hart
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Supply ◽  
Swimming Activity ◽  
Respiratory Metabolism ◽  
Critical Levels

The respiratory metabolism of groups of goldeye was measured during rest and sustained swimming activity at 5, 10, and 15 C under conditions of continuous reduction in oxygen by the metabolism of the fish. The oxygen consumption fell progressively during swimming at all temperatures indicating dependence of metabolism on oxygen supply at all pO2 levels. During rest the oxygen consumption was relatively independent of pO2 until certain critical levels were reached. Respiration became markedly limited by CO2 in the medium when the pCO2 exceeded 50 mm Hg. It is apparent that survival possibilities of goldeye would be limited by pO2 and pCO2 between 20–40 mm Hg during the winter.

The respiratory metabolism of temperature-adapted flatfish at rest and during swimming activity and the use of anaerobic metabolism at moderate swimming speeds

1982 ◽  
Vol 97 (1) ◽  
pp. 359-373 ◽  
Author(s):  
G. G. Duthie
Keyword(s):  
Oxygen Consumption ◽  
Lactic Acid ◽  
White Muscle ◽  
Anaerobic Metabolism ◽  
Swimming Activity ◽  
Respiratory Metabolism ◽  
Maximum Oxygen Consumption ◽  
Cost Of Locomotion ◽  
The Cost ◽  
The Relationship

(1) The standard oxygen consumption and the oxygen consumption during measured swimming activity have been determined in three flatfish species at 5, 10 and 15 degrees C. (2) The relationship between weight and standard oxygen consumption for flatfish conform to the general relationship Y = aWb. On an interspecies basis, standard oxygen consumption of flatfish is significantly lower than that of roundfish. (3) A semilogarithmic model describes the relationship between oxygen consumption and swimming speed for the three species. Values for maximum oxygen consumption, metabolic scopes and critical swimming speeds are low in comparison to salmonids. (4) The optimum swimming speeds and critical swimming speeds of flatfish are similar. It is suggested that, over long distances, flatfish adopt a strategy of swimming at supercritical speeds with periods of intermittent rest to repay the accrued oxygen debt. (5) Elevated lactic acid levels in flounder white muscle after moderate swimming indicate an additional 15% anaerobic contribution to the cost of locomotion as calculated from aerobic considerations.

Respiratory Metabolism During Pregnancy in the Guinea Pig

1957 ◽  
Vol 190 (3) ◽  
pp. 425-428 ◽  
Author(s):  
Richard M. Hoar ◽  
William C. Young
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Guinea Pig ◽  
Metabolic Rate ◽  
Adrenal Cortex ◽  
Guinea Pigs ◽  
Sharp Decrease ◽  
Zona Fasciculata ◽  
Respiratory Metabolism ◽  
Morphological Differences

Oxygen consumption and heart rate during pregnancy were measured in untreated, thyroxin-injected and thyroidectomized guinea pigs given I131. From impregnation until parturition, oxygen consumption increased 7.9% in untreated females. The increase continued until 5 days postpartum when a sharp decrease occurred. The increase is not accounted for by growth of the fetal mass. Comparable increases occurred in thyroxin-injected (16.2%) and thyroidectomized (11.9%) females, although the levels throughout were higher and lower, respectively, than in intact females. Heart rate did not increase. On the contrary, statistically significant decreases occurred in the untreated and thyroxin-injected females. Although the mechanism associated with the increased metabolic rate is not known, the possibility of thyroid participation would seem to be excluded. Involvement of the adrenal cortex is suggested by morphological differences in the cells of the zona fasciculata in pregnant and nonpregnant females and by evidence cited from other studies.

scholarly journals Using dual-calibrated functional MRI to map brain oxygen supply and consumption in multiple sclerosis

2021 ◽  
Author(s):  
Hannah L Chandler ◽  
Rachael C Stickland ◽  
Michael Germuska ◽  
Eleonora Patitucci ◽  
Catherine Foster ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Oxygen Consumption ◽  
Healthy Volunteers ◽  
Oxygen Supply ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Group Differences ◽  
Lesion Volume ◽  
Brain Physiology ◽  
Significant Difference

Evidence suggests that cerebrovascular function and oxygen consumption are altered in multiple sclerosis (MS). Here, we quantified the vascular and oxygen metabolic MRI burden in patients with MS (PwMS) and assessed the relationship between these MRI measures of and metrics of damage and disability. In PwMS and in matched healthy volunteers, we applied a newly developed dual-calibrated fMRI method of acquisition and analysis to map grey matter (GM) cerebral blood flow (CBF), oxygen extraction fraction (OEF), cerebral metabolic rate of oxygen consumption (CMRO2) and effective oxygen diffusivity of the capillary network (DC). We also quantified physical and cognitive function in PwMS and controls. There was no significant difference in GM volume between 22 PwMS and 20 healthy controls (p=0.302). Significant differences in CBF (PwMS vs. controls: 44.91 +/- 6.10 vs. 48.90 +/- 5.87 ml/100g/min, p=0.010), CMRO2 (117.69 +/- 17.31 vs. 136.49 +/- 14.48 μmol/100g/min p<0.001) and DC (2.70 +/- 0.51 vs. 3.18 +/- 0.41 μmol/100g/mmHg/min, p=0.002) were observed in the PwMS. No significant between-group differences were observed for OEF (PwMS vs. controls: 0.38 +/- 0.09 vs. 0.39 +/- 0.02, p=0.358). Regional analysis showed widespread reductions in CMRO2 and DC for PwMS compared to healthy volunteers. There was a significant correlation between physiological measures and T2 lesion volume, but no association with current clinical disability. Our findings demonstrate concurrent reductions in oxygen supply and consumption in the absence of an alteration in oxygen extraction that may be indicative of a reduced demand for oxygen (O2), an impaired transfer of O2 from capillaries to mitochondria, and/or a reduced ability to utilise O2 that is available at the mitochondria. With no between-group differences in GM volume, our results suggest that changes in brain physiology may precede MRI-detectable GM loss and thus may be one of the pathological drivers of neurodegeneration and disease progression.

scholarly journals Reviews and syntheses: Present, past, and future of the oxygen minimum zone in the northern Indian Ocean

2020 ◽  
Vol 17 (23) ◽  
pp. 6051-6080
Author(s):  
Tim Rixen ◽  
Greg Cowie ◽  
Birgit Gaye ◽  
Joaquim Goes ◽  
Helga do Rosário Gomes ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Indian Ocean ◽  
Nitrogen Cycle ◽  
Bay Of Bengal ◽  
Arabian Sea ◽  
Oxygen Supply ◽  
Northern Indian Ocean ◽  
Minimum Zone ◽  
Oxygen Minimum ◽  
Oxygen Concentrations

Abstract. Decreasing concentrations of dissolved oxygen in the ocean are considered one of the main threats to marine ecosystems as they jeopardize the growth of higher organisms. They also alter the marine nitrogen cycle, which is strongly bound to the carbon cycle and climate. While higher organisms in general start to suffer from oxygen concentrations < ∼ 63 µM (hypoxia), the marine nitrogen cycle responds to oxygen concentration below a threshold of about 20 µM (microbial hypoxia), whereas anoxic processes dominate the nitrogen cycle at oxygen concentrations of < ∼ 0.05 µM (functional anoxia). The Arabian Sea and the Bay of Bengal are home to approximately 21 % of the total volume of ocean waters revealing microbial hypoxia. While in the Arabian Sea this oxygen minimum zone (OMZ) is also functionally anoxic, the Bay of Bengal OMZ seems to be on the verge of becoming so. Even though there are a few isolated reports on the occurrence of anoxia prior to 1960, anoxic events have so far not been reported from the open northern Indian Ocean (i.e., other than on shelves) during the last 60 years. Maintenance of functional anoxia in the Arabian Sea OMZ with oxygen concentrations ranging between > 0 and ∼ 0.05 µM is highly extraordinary considering that the monsoon reverses the surface ocean circulation twice a year and turns vast areas of the Arabian Sea from an oligotrophic oceanic desert into one of the most productive regions of the oceans within a few weeks. Thus, the comparably low variability of oxygen concentration in the OMZ implies stable balances between the physical oxygen supply and the biological oxygen consumption, which includes negative feedback mechanisms such as reducing oxygen consumption at decreasing oxygen concentrations (e.g., reduced respiration). Lower biological oxygen consumption is also assumed to be responsible for a less intense OMZ in the Bay of Bengal. According to numerical model results, a decreasing physical oxygen supply via the inflow of water masses from the south intensified the Arabian Sea OMZ during the last 6000 years, whereas a reduced oxygen supply via the inflow of Persian Gulf Water from the north intensifies the OMZ today in response to global warming. The first is supported by data derived from the sedimentary records, and the latter concurs with observations of decreasing oxygen concentrations and a spreading of functional anoxia during the last decades in the Arabian Sea. In the Arabian Sea decreasing oxygen concentrations seem to have initiated a regime shift within the pelagic ecosystem structure, and this trend is also seen in benthic ecosystems. Consequences for biogeochemical cycles are as yet unknown, which, in addition to the poor representation of mesoscale features in global Earth system models, reduces the reliability of estimates of the future OMZ development in the northern Indian Ocean.

Oxygen partial pressure and free intracellular adenosine of isolated cardiomyocytes

1991 ◽  
Vol 260 (4) ◽  
pp. C708-C714 ◽  
Author(s):  
R. T. Smolenski ◽  
J. Schrader ◽  
H. de Groot ◽  
A. Deussen
Keyword(s):  
Oxygen Consumption ◽  
Extracellular Space ◽  
Oxygen Supply ◽  
Oxygen Demand ◽  
Nucleoside Transport ◽  
Isolated Cardiomyocytes ◽  
Homocysteine Thiolactone ◽  
Rat Cardiomyocytes ◽  
Extracellular Adenosine ◽  
Adenosine Concentration

Adenosine formation by the heart is known to critically depend on the ratio of oxygen supply to oxygen demand, but the sensitivity of cardiomyocytes to defined changes in PO2 is not known. Isolated metabolically stable rat cardiomyocytes were incubated up to 45 min at constant PO2 values ranging from 0.1 to 100 mmHg using a feedback-controlled incubation system (oxystat system). Changes of the free intracellular adenosine concentration were measured after trapping of adenosine by cytosolic S-adenosylhomocysteine (SAH) hydrolase in the presence of 200 microM L-homocysteine thiolactone. Rate of SAH formation was constant at a PO2 between 3 and 100 mmHg and gradually increased at PO2 less than 3 mmHg. Cellular ATP decreased only at PO2 less than 1 mmHg, and this was accompanied by a decline of oxygen consumption. Treatment of cells with 5.5 mM deoxyglucose and 4 micrograms/ml oligomycin increased SAH formation 60-fold and was associated with elevated intra- and to a lesser extent extracellular adenosine levels. Inhibition of nucleoside transport with 20 microM S-(p-nitrobenzyl)-6-thioinosine steepened the transmembrane adenosine gradient. Our findings suggest that the cardiomyocyte responds to metabolic poisoning and oxygen deprivation with an enhanced formation of adenosine. This adenosine is mainly formed intracellularly and reaches the extracellular space by diffusion. Threshold for adenosine formation is as low as 3 mmHg.

scholarly journals The duration of the recovery period following strenuous muscular exercise

1933 ◽  
Vol 113 (783) ◽  
pp. 327-344 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Normal Values ◽  
Recovery Period ◽  
Oxygen Intake ◽  
Respiratory Metabolism ◽  
Carbon Dioxide Output ◽  
Steady Level ◽  
Made In

There are a variety of ways in which the duration of the recovery period after exercise can be determined. The method most frequently employed depends upon observations of the respiratory metabolism. This method has been chosen because the respiratory changes due to exercise can be followed with reasonable ease and accuracy, and because these changes are among the last of the more obvious effects of the exercise to disappear during recovery. In addition, interesting data concerning the effects of exercise on respiratory metabolism can be collected during the determination of the duration of the recovery period when this method is used. In determining the duration of the recovery period by observation of the respiratory metabolism, it is necessary to decide when the carbon dioxide output and oxygen intake have returned to their normal values and are no longer affected by the process of recovery from the exercise. This decision has been made in a variety of ways by different investigators. Some have made one or more pre-exercise determinations of the subject's basal oxygen intake and carbon dioxide output. Recovery was said to be complete when the carbon dioxide output and oxygen consumption returned to these values after exercise. Others found that the oxygen consumption did not return to the pre-exercise level within a reasonable length of time, but remained above normal for several hours. They considered that recovery was complete when the carbon dioxide output and oxygen intake returned to a steady level after exercise, even if the level was not the same as that before exercise.

Continuous measurement of oxygen supply and oxygen consumption - first data on a new monitoring concept

1991 ◽  
Vol 75 (3) ◽  
pp. A456-A456 ◽  
Author(s):  
M. Specht ◽  
K. Wichmann ◽  
Chr. Apenburg ◽  
R. W. Johnson ◽  
K. Reinhart
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Supply ◽  
Continuous Measurement
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