Oxygen consumption and blood gases ofOctopus vulgaris in hypoxic conditions

Fat oxidation during exercise is associated with cardio-metabolic benefits, but the extent of which whole-body exercise modality elicits the greatest fat oxidation remains unclear. We investigated the effects of treadmill, elliptical and rowing exercise on fat oxidation in healthy individuals. Nine healthy males participated in three, peak oxygen consumption tests, on a treadmill, elliptical and rowing ergometer. Indirect calorimetry was used to assess maximal oxygen consumption (V̇O2peak), maximal fat oxidation (MFO) rates, and the exercise intensity MFO occurred (Fatmax). Mixed venous blood was collected to assess lactate and blood gases concentrations. While V̇O2peak was similar between exercise modalities, MFO rates were higher on the treadmill (mean ± SD; 0.61 ± 0.06 g·min-1) compared to both the elliptical (0.41 ± 0.08 g·min-1, p = 0.022) and the rower (0.40 ± 0.08 g·min-1, p = 0.017). Fatmax values were also significantly higher on the treadmill (56.0 ± 6.2 %V̇O2peak) compared to both the elliptical (36.8 ± 5.4 %V̇O2peak, p = 0.049) and rower (31.6 ± 5.0 %V̇O2peak, p = 0.021). Post-exercise blood lactate concentrations were also significantly lower following treadmill exercise (p = 0.021). Exercising on a treadmill maximizes fat oxidation to a greater extent than elliptical and rowing exercises, and remains an important exercise modality to improve fat oxidation, and consequently, cardio-metabolic health.

Download Full-text

Oxygen Consumption Under Hypoxic Conditions

Low-Oxygen Stress in Plants - Plant Cell Monographs ◽

10.1007/978-3-7091-1254-0_10 ◽

2013 ◽

pp. 185-208 ◽

Cited By ~ 3

Author(s):

Carola Päpke ◽

Santiago Ramirez-Aguilar ◽

Carla Antonio

Keyword(s):

Oxygen Consumption ◽

Hypoxic Conditions

Download Full-text

Function of myoglobin in oxygen consumption by isolated perfused fish hearts

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1986.251.6.r1144 ◽

1986 ◽

Vol 251 (6) ◽

pp. R1144-R1150 ◽

Cited By ~ 1

Author(s):

J. R. Bailey ◽

W. R. Driedzic

Keyword(s):

Oxygen Consumption ◽

Partial Pressure ◽

Binding Protein ◽

Protective Role ◽

Cardiac Performance ◽

O2 Consumption ◽

Hypoxic Conditions ◽

Sea Raven ◽

Hemitripterus Americanus ◽

O2 Binding

Myoglobin, an intracellular O2-binding protein, plays a protective role in maintaining performance of isolated fish hearts under hypoxic conditions. This study was designed to test the hypothesis that the protein contributes to O2 consumption under conditions of increased O2 demand or hypoxia. Isolated myoglobin-rich sea raven (Hemitripterus americanus) hearts and myoglobin-poor ocean pout (Macrozoarces americanus) hearts were perfused under conditions of changing partial pressure of O2 (PO2) and afterload. Sea raven hearts maintained O2 consumption and cardiac performance at low PO2 and high afterload, whereas ocean pout hearts did not. In other cases sea raven and ocean pout hearts were treated with hydroxylamine, which renders myoglobin incapable of binding O2, and subjected to changing PO2 and afterload. Sea raven hearts could not maintain O2 consumption and cardiac performance, whereas hydroxylamine treatment had no effect on O2 consumption in ocean pout hearts under these conditions. These data provide the first evidence to support the concept that myoglobin plays a role in O2 consumption of hearts.

Download Full-text

Postinduction butorphanol administration alters oxygen consumption to improve blood gases in etorphine-immobilized white rhinoceros

Veterinary Anaesthesia and Analgesia ◽

10.1016/j.vaa.2017.03.008 ◽

2018 ◽

Vol 45 (1) ◽

pp. 57-67 ◽

Cited By ~ 11

Author(s):

Peter Buss ◽

Michele Miller ◽

Andrea Fuller ◽

Anna Haw ◽

Eliza Stout ◽

...

Keyword(s):

Oxygen Consumption ◽

Blood Gases ◽

White Rhinoceros

Download Full-text

Ephemeral hypoxia reduces oxygen consumption in the Caribbean coral Orbicella faveolata

Coral Reefs ◽

10.1007/s00338-021-02197-5 ◽

2021 ◽

Author(s):

Philip M. Gravinese ◽

Alex Douwes ◽

Katherine R. Eaton ◽

Erinn M. Muller

Keyword(s):

Oxygen Consumption ◽

Elevated Temperature ◽

Coastal Waters ◽

Elevated Temperatures ◽

Wet Season ◽

Negative Effects ◽

Hypoxic Conditions ◽

Orbicella Faveolata ◽

The Caribbean ◽

Solubility Of Oxygen

AbstractOxygen concentrations in coastal waters have declined globally by 10% since the mid-twentieth century, and ocean warming will further reduce the solubility of oxygen in coastal habitats. Some nearshore reefs experience periodic hypoxic conditions due to eutrophication, especially during the wet season. Here, we determined the combined impacts of hypoxia and elevated temperature on the reef-building coral, Orbicella faveolata, by exposing corals to normoxic or hypoxic conditions and ambient or elevated temperatures. Oxygen consumption was monitored using closed-system respirometry. Corals within hypoxic conditions consumed 34% less oxygen relative to corals in normoxic conditions. Corals in the elevated temperature normoxic treatment experienced a 10% increase in oxygen consumption relative to the control. Corals exposed to both stressors simultaneously experienced a 62% reduction in oxygen consumption. These results suggest that increased temperature may exacerbate the negative effects of hypoxia on O. faveolata.

Download Full-text

Characterisation of an Isogenic Model of Cisplatin Resistance in Oesophageal Adenocarcinoma Cells

Pharmaceuticals ◽

10.3390/ph12010033 ◽

2019 ◽

Vol 12 (1) ◽

pp. 33 ◽

Cited By ~ 4

Author(s):

Amy Buckley ◽

Becky Bibby ◽

Margaret Dunne ◽

Susan Kennedy ◽

Maria Davern ◽

...

Keyword(s):

Gene Expression ◽

Oxygen Consumption ◽

Oxygen Consumption Rate ◽

Consumption Rate ◽

Cisplatin Resistance ◽

Oesophageal Adenocarcinoma ◽

Phenotypic Changes ◽

Hypoxic Conditions ◽

P Cells ◽

Resistant Cells

Cisplatin (cis-diamminedichloroplatinum) is widely used for the treatment of solid malignancies; however, the development of chemoresistance hinders the success of this chemotherapeutic in the clinic. This study provides novel insights into the molecular and phenotypic changes in an isogenic oesophageal adenocarcinoma (OAC) model of acquired cisplatin resistance. Key differences that could be targeted to overcome cisplatin resistance are highlighted. We characterise the differences in treatment sensitivity, gene expression, inflammatory protein secretions, and metabolic rate in an isogenic cell culture model of acquired cisplatin resistance in OAC. Cisplatin-resistant cells (OE33 Cis R) were significantly more sensitive to other cytotoxic modalities, such as 2 Gy radiation (p = 0.0055) and 5-fluorouracil (5-FU) (p = 0.0032) treatment than parental cisplatin-sensitive cells (OE33 Cis P). Gene expression profiling identified differences at the gene level between cisplatin-sensitive and cisplatin-resistant cells, uncovering 692 genes that were significantly altered between OE33 Cis R cells and OE33 Cis P cells. OAC is an inflammatory-driven cancer, and inflammatory secretome profiling identified 18 proteins secreted at significantly altered levels in OE33 Cis R cells compared to OE33 Cis P cells. IL-7 was the only cytokine to be secreted at a significantly higher levels from OE33 Cis R cells compared to OE33 Cis P cells. Additionally, we profiled the metabolic phenotype of OE33 Cis P and OE33 Cis R cells under normoxic and hypoxic conditions. The oxygen consumption rate, as a measure of oxidative phosphorylation, is significantly higher in OE33 Cis R cells under normoxic conditions. In contrast, under hypoxic conditions of 0.5% O2, the oxygen consumption rate is significantly lower in OE33 Cis R cells than OE33 Cis P cells. This study provides novel insights into the molecular and phenotypic changes in an isogenic OAC model of acquired cisplatin resistance, and highlights therapeutic targets to overcome cisplatin resistance in OAC.

Download Full-text

Implications of water flow and oxygen gradients for molluscan oxygen uptake and respirometric measurements

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315406013257 ◽

2006 ◽

Vol 86 (2) ◽

pp. 401-402 ◽

Cited By ~ 2

Author(s):

Sandra Irwin ◽

John Davenport

Keyword(s):

Oxygen Consumption ◽

Oxygen Uptake ◽

Extraction Efficiency ◽

Littorina Littorea ◽

Surrounding Water ◽

Hypoxic Conditions ◽

Oxygen Gradients ◽

Tissue Surface ◽

Ventilatory Capacity ◽

Static Conditions

Oxygen microenvironments adjacent to mussel (Mytilus edulis) and periwinkle (Littorina littorea) tissues were described using micro-optodes. For mussels these environments did not differ from the surrounding water body in either static or stirred conditions. Consequently no difference was seen in the MO2 of mussels within stirred and unstirred respirometers. An oxygen extraction efficiency of 30% was recorded for mussels in stirred and unstirred conditions. Under static conditions, periwinkles, with their weak ventilatory arrangements, were not capable of ventilating the surrounding water efficiently, and their tissues were surrounded by hypoxic seawater, even in fully aerated water. The resultant build up of oxygen gradients close to the tissue surface led to measures of oxygen consumption representative of hypoxic conditions in fully aerated, unstirred respirometers. Stirring of the contents of the respirometer immediately prior to final oxygen concentration measures was insufficient to counter this effect, which could only be avoided by continuous artificial stirring of the respirometric chamber water. These findings have considerable implications for study of the oxygen consumption of aquatic animals with limited ventilatory capacity, such as gastropod molluscs.

Download Full-text

Omeprazole and cimetidine versus pentagastrin in canine ex vivo gastric chamber

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1989.256.2.g390 ◽

1989 ◽

Vol 256 (2) ◽

pp. G390-G395 ◽

Cited By ~ 1

Author(s):

K. R. Larsen ◽

M. M. Ives ◽

N. F. Jensen ◽

E. Carlsson ◽

H. Larsson

Keyword(s):

Blood Flow ◽

Oxygen Consumption ◽

Ex Vivo ◽

Venous Blood ◽

Blood Gases ◽

Mucosal Blood Flow ◽

Systemic Blood Pressure ◽

Potential Difference ◽

Gastric Blood Flow ◽

Dose Dependent

The effects of acid inhibitory doses of omeprazole were compared with equieffective doses of cimetidine in the canine ex vivo stomach model (n = 30). Systemic blood pressure, temperature, stomach fluid and ion fluxes, potential difference, blood flow rates, and arterial and venous blood gases were monitored during each of nine 30-min periods. Two resting periods preceded seven periods of pentagastrin stimulation. During the last four of these, the drug effect was recorded (cimetidine 1.2 or 4.8 mumol.kg-1.h-1; omeprazole 0.3, 0.6, or 1.2 mumol/kg). Omeprazole (1.2 mumol/kg) produced 100% inhibition of stimulated acid efflux, no significant decrease in total gastric blood flow (venous outflow), 90% return of potential difference (PD) toward resting values, and a 55% reduction in stimulated oxygen consumption. Omeprazole also showed a dose-dependent K+ efflux at the two lower doses. Cimetidine (4.8 mumol.kg-1.h-1) given during pentagastrin stimulation showed a 70% decrease in total gastric blood flow, a 40% return of PD toward resting, and a 77% reduction in stimulated oxygen consumption. Neither drug showed significant changes in mucosal blood flow from resting values, thus supporting the principle that changes in gastric acid secretion and changes in blood flow are not necessarily correlated.

Download Full-text

Roles of nitric oxide synthase and cyclooxygenase in leg vasodilation and oxygen consumption during prolonged low-intensity exercise in untrained humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.00326.2010 ◽

2010 ◽

Vol 109 (3) ◽

pp. 768-777 ◽

Cited By ~ 28

Author(s):

William G. Schrage ◽

Brad W. Wilkins ◽

Christopher P. Johnson ◽

John H. Eisenach ◽

Jacqueline K. Limberg ◽

...

Keyword(s):

Nitric Oxide ◽

Blood Flow ◽

Young Adults ◽

Oxygen Consumption ◽

Steady State ◽

Nitric Oxide Synthase ◽

Muscle Blood Flow ◽

Blood Gases ◽

Whole Body ◽

Oxide Synthase

The vasodilator signals regulating muscle blood flow during exercise are unclear. We tested the hypothesis that in young adults leg muscle vasodilation during steady-state exercise would be reduced independently by sequential pharmacological inhibition of nitric oxide synthase (NOS) and cyclooxygenase (COX) with NG-nitro-l-arginine methyl ester (l-NAME) and ketorolac, respectively. We tested a second hypothesis that NOS and COX inhibition would increase leg oxygen consumption (V̇o2) based on the reported inhibition of mitochondrial respiration by nitric oxide. In 13 young adults, we measured heart rate (ECG), blood pressure (femoral venous and arterial catheters), blood gases, and venous oxygen saturation (indwelling femoral venous oximeter) during prolonged (25 min) steady-state dynamic knee extension exercise (60 kick/min, 19 W). Leg blood flow (LBF) was determined by Doppler ultrasound of the femoral artery. Whole body V̇o2 was measured, and leg V̇o2 was calculated from blood gases and LBF. Resting intra-arterial infusions of acetylcholine (ACh) and nitroprusside (NTP) tested inhibitor efficacy. Leg vascular conductance (LVC) to ACh was reduced up to 53 ± 4% by l-NAME + ketorolac infusion, and the LVC responses to NTP were unaltered. Exercise increased LVC from 4 ± 1 to 33.1 ± 2 ml·min−1·mmHg−1 and tended to decrease after l-NAME infusion (31 ± 2 ml·min−1·mmHg−1, P = 0.09). With subsequent administration of ketorolac LVC decreased to 29.6 ± 2 ml·min−1·mmHg−1 ( P = 0.02; n = 9). While exercise continued, LVC returned to control values (33 ± 2 ml·min−1·mmHg−1) within 3 min, suggesting involvement of additional vasodilator mechanisms. In four additional subjects, LVC tended to decrease with l-NAME infusion alone ( P = 0.08) but did not demonstrate the transient recovery. Whole body and leg V̇o2 increased with exercise but were not altered by l-NAME or l-NAME + ketorolac. These data indicate a modest role for NOS- and COX-mediated vasodilation in the leg of exercising humans during prolonged steady-state exercise, which can be restored acutely. Furthermore, NOS and COX do not appear to influence muscle V̇o2 in untrained healthy young adults.

Download Full-text