MAINTENANCE OF OXYGEN CONSUMPTION IN RESTING SILURUS GLANIS AT DIFFERENT LEVELS OF AMBIENT OXYGENATION

1989 ◽  
Vol 143 (1) ◽  
pp. 305-319 ◽  
Author(s):  
JEAN FORGUE ◽  
BERNARD BURTIN ◽  
JEAN-CHARLES MASSABUAU
Keyword(s):  
Oxygen Consumption ◽  
Venous Blood ◽  
Blood Flow Rate ◽  
Binding Characteristics ◽  
Silurus Glanis ◽  
Arterial Blood ◽  
O2 Partial Pressure ◽  
O2 Extraction ◽  
O2 Concentration ◽  
Mechanisms Of Adaptation

The mechanisms of adaptation that allow the teleost Silurus glanis to maintain its resting oxygen consumption constant when the O2 partial pressure (PO2) m the inspired water (PIO2) varied between 40 and 3kPa were studied at 13 °C. Steadystate values of oxygen consumption, ventilatory and circulatory flow rates, PO2 in the inspired and expired water, PO2 and O2 concentration in the arterial and venous blood, haematocrit and acid--base status in the arterial blood were determined after 1-day exposures at selected PIO2 values. Whole-blood O2-binding characteristics were also determined. The key adaptation after 1 day of acclimation was maintenance of oxygen consumption by ventilatory adjustment with no change in blood flow rate or pH (no Bohr effect). At each PIO2 value (i) the ventilatory adjustment was minimal as the O2 extraction coefficient from water always remained around 80–90 % and (ii) PaO2 stayed constant at about 2kPa. Data are compared with previous results in crayfish and other teleosts. It is concluded that the principle of a constant O2 status in themilieu intérieur -- independent of large changes in PIO2 for a given state of activity -- should be valid in many crustaceans and teleosts.

Oxygen transport and oxygen consumption vs. cardiac output at different haematocrits

Perfusion ◽  
1987 ◽  
Vol 2 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Esther P Hill ◽  
David C Willford ◽  
William Y Moores ◽  
Ronald Bellamy ◽  
William H Heydorn
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Flow Rate ◽  
Oxygen Transport ◽  
Blood Flow Rate ◽  
Fick Principle ◽  
Pump Flow ◽  
Arterial Blood ◽  
Group I ◽  
Pump Flow Rate

Oxygen consumption was measured in 10 anaesthetized, surgically instrumented domestic pigs on cardiopulmonary bypass while cardiac output (pump flow rate) was decreased. Oxygen consumption data (calculated by the Fick principle from blood flow rate and arterial and mixed venous content measurements) were plotted against total oxygen transport (TOT=QCaO2, where Q is pump flow rate and CaO2 is arterial blood oxygen content). Oxygen consumption (VO2) measurements were made in each animal at two haematocrits (approximately 30%, which is normal for pigs, and approximately 15%). In five of the animals (Group I) the measurements were made with normal haematocrit first, the blood was then haemodiluted with plasma or Dextran, and the measurements were repeated. In the remaining five animals (Group II), the haematocrit orderwas reversed. The plots showed two regions: above a certain value of TOT which we call critical TOT, VO2 was relatively independent of TOT, while at lower values of TOT, VO2 decreased approximately linearly with TOT. At the low haematocrit, the critical TOT (±S.E.M) was significantly lower ( P <0.05) than at normal haematocrit (6.9 ± 0.9 vs. 10.7 ± 1.2 ml/min/kg). Below the critical TOT, the curves for the two haematocrit levels were not significantly different. Above the critical TOT, the average VO2 was lower at the low haematocrit than at the normal haematocrit (6.0 ± 0.6 vs. 8.8 ± 1.1 ml/min/kg).

Liver blood flow and oxygen consumption during hypocapnia and IPPV in the greyhound

1979 ◽  
Vol 47 (2) ◽  
pp. 290-295 ◽  
Author(s):  
R. L. Hughes ◽  
R. T. Mathie ◽  
W. Fitch ◽  
D. Campbell
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Airway Pressure ◽  
Venous Blood ◽  
Liver Blood Flow ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Hepatic Arterial Blood Flow ◽  
Arterial Blood ◽  
Intermittent Positive Pressure Breathing

Pentobarbital-anesthetized greyhounds were passively hyperventilated using intermittent positive-pressure breathing (IPPV) and the effects of raised airway pressure, accompanied by hypocapnia and then by normocapnia, on liver blood flow and oxygen consumption were studied. Electromagnetic flowmeters were used to measure hepatic arterial, portal venous, and splenic venous blood flow. Studies were carried out at three levels of raised airway pressure, both at normocapnia and hypocapnia. It was found that hypocapnic hyperventilation produced a decrease in portal venous and hepatic arterial blood flow. Normocapnic hyperventilation resulted in a restoration of portal venous blood flow but with a further decrease in hepatic arterial blood flow. A decrease in oxygen consumption with hypocapnia, returning to control values with normocapnia, was seen. It is suggested that the reduction in liver blood flow and oxygen consumption seen with passive hyperventilation is chiefly an effect of hypocapnia and is largely reversed by restoration of normocapnia.

A new procedure for the continuous measurement of oxygen consumption in pigs

1995 ◽  
Vol 124 (1) ◽  
pp. 113-118 ◽  
Author(s):  
L. R. Giles ◽  
E. F. Annison ◽  
J. L. Black ◽  
R. G. Tucker ◽  
J. M. Gooden
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Pulmonary Artery ◽  
Transit Time ◽  
Venous Blood ◽  
Growing Pigs ◽  
Whole Body ◽  
Mixed Venous Blood ◽  
Fibre Optic ◽  
Arterial Blood

SUMMARYWhole-body oxygen (O2) consumption was measured continuously in pigs from the product of blood flow through the pulmonary artery and arterio-venous (AV) difference of blood O2 content across the lungs (pulmonary AV procedure). Blood flow in the pulmonary artery, a measure of cardiac output, was monitored continuously using a transit-time ultrasound flow probe surgically implanted around the artery. The O2 content of pulmonary artery blood, which represents mixed venous blood O2 aturation (SvO2) was recorded continuously by fibre-optic oximetry. The relative constancy of arterial blood oxygen saturation (SaO2), obtained by catheterization of the saphenous artery, obviated the need for continuous monitoring. Complete recovery from surgical procedures, as indicated by the absence of infection and a return to pre-surgery food intake, occurred in 3–5 days. The combination of transit-time ultrasound and fibre-optic oximetry allowed the pulmonary AV procedure to provide continuous data on the oxygen consumption of growing pigs at high temperatures.

Time course of muscular blood metabolites during forearm rhythmic exercise in hypoxia

1986 ◽  
Vol 60 (4) ◽  
pp. 1203-1208 ◽  
Author(s):  
J. Raynaud ◽  
D. Douguet ◽  
P. Legros ◽  
A. Capderou ◽  
B. Raffestin ◽  
...  
Keyword(s):  
Time Course ◽  
Venous Blood ◽  
Blood Gases ◽  
Arterial Blood ◽  
O2 Concentration ◽  
Rhythmic Exercise ◽  
Underlying Mechanisms ◽  
Arterial Po2 ◽  
Local Metabolism ◽  
Blood Data

O2 concentration, PO2, PCO2, pH, osmolarity, lactate (LA), and hemoglobin (Hb) concentrations in deep forearm venous blood were repeatedly measured during submaximal exercise of forearm muscles. Concentrations of arterial blood gases were determined at rest and during exercise. Experiments were conducted under normoxia and hypobaric hypoxia (PB = 465 Torr). In arterial blood, data obtained during exercise were the same as those obtained during rest under either normoxia or hypoxia. In venous muscular blood, PO2 and O2 concentration were lower at rest and during exercise in hypoxia. The muscular arteriovenous O2 difference during exercise in hypoxia was increased by no more than 10% compared with normoxia, which implied that muscular blood flow during exercise also increased by the same percentage, if we assume that exercise O2 consumption was not affected by hypoxia. Despite increased [LA], the magnitude of changes in PCO2 and pH in hypoxia were smaller than in normoxia during exercise and recovery; this finding is probably due to the increased blood buffer value induced by the greater amount of reduced Hb in hypoxia. Hence all the changes occurring in hypoxia showed that local metabolism was less affected than we expected from the decrease in arterial PO2. The rise in [Hb] that occurred during exercise was lower in hypoxia. Possible underlying mechanisms of the [Hb] rise during exercise are discussed.

Liver Blood Flow and Oxygen Consumption during Metabolic Acidosis and Alkalosis in the Greyhound

1981 ◽  
Vol 60 (4) ◽  
pp. 355-361 ◽  
Author(s):  
R. L. Hughes ◽  
R. T. Mathie ◽  
W. Fitch ◽  
D. Campbell
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Venous Blood ◽  
Liver Blood Flow ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Hepatic Arterial Blood Flow ◽  
Portal Venous Blood Flow ◽  
Arterial Blood ◽  
Portal Venous Blood

1. Hepatic arterial and portal venous blood flow and hepatic oxygen consumption were measured in two groups of greyhounds anaesthetized with pentobarbitone. Flows were measured with electromagnetic flowmeters. 2. In the first group the effects of metabolic acidosis produced by the infusion of a molar solution of lactic acid were studied. In the second group the effects of metabolic alkalosis produced by the infusion of a molar solution of sodium bicarbonate were studied. 3. In the acidotic group hepatic arterial blood flow decreased from 35.2 to 9.6 ml min− 100 g− of liver whereas portal venous blood flow increased from 94.2 to 126.1 ml min− 100 g− of liver. Total liver blood flow was unchanged. Hepatic oxygen consumption increased, but not significantly, while hepatic venous oxygen content decreased significantly. Hepatic arterial resistance increased from 1.18 to 2.77 mmHg min− ml− while peripheral resistance was virtually unchanged. Portal venous pressure increased from 7.08 to 11.6 mmHg. 4. In the alkalotic group portal venous blood flow increased from 112 to 137 ml min− 100 g− of liver. Hepatic arterial blood flow increased, but not significantly. Total liver blood flow increased from 151 to 185, ml min− 100 mg− of liver. There were no significant changes in hepatic oxygen consumption. 5. It is concluded that metabolic acidosis reduces the supply of oxygen to the liver owing to the reduction in hepatic arterial blood flow and is therefore potentially harmful, whereas metabolic alkalosis probably has no biologically significant effect on liver blood flow.

Oxygen Transport by the Circulatory System of the Green Iguana (Iguana Iguana) at Different Body Temperatures

1966 ◽  
Vol 44 (1) ◽  
pp. 77-92
Author(s):  
VANCE A. TUCKER
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Venous Blood ◽  
Circulatory System ◽  
Body Temperatures ◽  
Iguana Iguana ◽  
Arterial Blood ◽  
Percentage Saturation ◽  
The Right

1. Oxygen consumption, stroke volume, heart rate and the difference in oxygen contents of arterial and venous blood (AV difference) were measured in the resting iguana at body temperatures of 20, 30 and 38° C. Oxygen consumption increased by a factor of 4.4 as temperature changed from 20 to 38° C. This increase was accomplished by a decrease in stroke volume by a factor of 0.5, and increases in heart rate and AV difference by factors of 4.1 and 2.2, respectively. 2. During activity increases in oxygen consumption at a given temperature were accompanied by increases in heart rate and AV difference, but stroke volume did not change consistently. 3. The percentage saturation of arterial blood with oxygen in the iguana may differ in the right and left systemic arches. In some lizards, both arches carried equally saturated blood, but in others the left arch carried blood containing less oxygen than the right arch. 4. An hypothesis is presented concerning the function of the double systemic arches and incompletely divided ventricles of lizards. These structures may be a device for permitting increased cardiac output associated with thermoregulation to bypass the lungs while maintaining a supply of well-oxygenated blood to the head. 5. Data on oxygen capacity, percentage saturation of blood with oxygen, haematocrit and pH of iguana blood are included in this study.

PARTITION OF ANDROGEN BETWEEN THE LYMPH AND VENOUS BLOOD OF THE TESTIS IN THE RAM

1963 ◽  
Vol 25 (4) ◽  
pp. 483-NP ◽  
Author(s):  
H. R. LINDNER
Keyword(s):  
General Circulation ◽  
Hormone Level ◽  
Venous Blood ◽  
Blood Flow Rate ◽  
Human Chorionic Gonadotrophin ◽  
Seminiferous Tubules ◽  
Tissue Fluid ◽  
Arterial Blood ◽  
Target Organs ◽  
The Mean

SUMMARY Testicular lymph collected from rams contained testosterone and androstenedione. The concentration of testosterone in testicular lymph ranged from < 2·5 to 10·6 μg./100 ml. in untreated rams, and from 8·9 to 61·4 μg./100 ml. in rams treated with human chorionic gonadotrophin, and was closely correlated with the hormone level in testicular venous blood. Testosterone concentration in lymph was lower than that in the plasma of spermatic vein blood (mean ratio 0·61), but was two to eight times higher than the concentration in arterial blood plasma. Blood flow rate through the testis (2–3 l./hr.) was 300 to 400 times higher than the mean rate of lymph collection (7·5 ml./hr./testis). It is concluded that only a very small fraction of the androgen output of the testis is carried to the general circulation in lymph. It appears, however, that androgen release is attended by escape of testosterone into the tissue fluid of the testis, and hence the seminiferous tubules may be exposed to much higher concentrations of the hormone than are androgen target organs remote from the testis.

scholarly journals THE OXYGEN AND CARBON DIOXIDE CONTENT OF ARTERIAL AND OF VENOUS BLOOD IN NORMAL INDIVIDUALS AND IN PATIENTS WITH ANEMIA AND HEART DISEASE

1919 ◽  
Vol 30 (3) ◽  
pp. 241-257 ◽  
Author(s):  
George A. Harrop
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Oxygen Content ◽  
Normal Values ◽  
Normal Individual ◽  
Venous Blood ◽  
Carbon Dioxide Content ◽  
Arterial Blood ◽  
Percentage Saturation ◽  
Normal Individuals

1. The oxygen content of venous and of arterial blood from fifteen essentially normal individuals at rest in bed has been determined. 2. The percentage saturation of the arterial blood has varied between 100 and 94.3. The average is 95.5 per cent. 3. The oxygen consumption has varied between 2.6 and 8.3 volumes per cent. 4. The oxygen content and the percentage saturation of arterial blood taken at close intervals from three different peripheral arteries of a normal individual have shown values agreeing within the limits of error. Analyses of the blood gases of a normal individual, at rest and after exercise, have shown a lowering of the percentage oxygen saturation of the arterial blood and a diminished carbon dioxide content after exercise. 5. In three persons with severe anemia the saturation of the arterial blood has not differed from the normal. Very low absolute values were found for the oxygen content of the venous blood, but the normal oxygen consumption has been maintained. 6. The carbon dioxide content of the arterial blood from ten normal individuals has varied between 54.7 and 44.6 volumes per cent. That of the venous blood has varied between 60.4 and 48.3 volumes per cent. 7. No deviations from the normal values for oxygen and carbon dioxide were found in venous and arterial blood from cardiac patients without arrhytiunias, well compensated, and at rest in bed. 8. A series of determinations has been made upon nine cardiac patients with varying degrees of decompensation. The percentage oxygen saturation of the arterial blood on admission was abnormally low in seven of these cases. With the return to compensation and with the clearing up of pulmonary symptoms, the percentage saturation of the arterial blood returned to normal in four of them. 9. In a case of long standing mitral endocarditis with auricular fibrillation it remained low over a period of I month of observation. 10. In a case of chronic myocarditis secondary to emphysema and chronic bronchitis, it remained low over the period of observation. 11. Normal values for the percentage saturation of the arterial blood were found in two individuals with decompensated aortic disease but without physical signs of extensive pulmonary involvement. 12. The oxygen consumption tended to be high in individuals with cardiac disease during the periods of marked decompensation and to be lower as compensation was regained. 13. The data presented indicate that at least in many circulatory diseases during decompensation, particularly when there are physical signs of pulmonary congestion, there is a disturbance of the pulmonary exchange, as indicated by the lowering of the percentage saturation of the arterial blood with oxygen.

Arterio-Venous Differences in the Components of the Fibrinolytic Enzyme System

1966 ◽  
Vol 16 (01/02) ◽  
pp. 032-037 ◽  
Author(s):  
D Ogston ◽  
C. M Ogston ◽  
N. B Bennett
Keyword(s):  
Plasminogen Activator ◽  
Enzyme System ◽  
Venous Blood ◽  
Fibrinolytic Enzyme ◽  
Blood Levels ◽  
Activator Concentration ◽  
Blood Samples ◽  
Arterial Blood ◽  
Male Subjects

Summary1. The concentration of the major components of the fibrinolytic enzyme system was compared in venous and arterial blood samples from male subjects.2. The plasminogen activator concentration was higher in venous blood and the arterio-venous difference increased as its concentration rose, but the ratio of the arterial to venous level remained constant.3. No arterio-venous difference was found for anti-urokinase activity, antiplasmin, plasminogen and fibrinogen.4. It is concluded that venous blood determinations of the components of the fibrinolytic enzyme system reflect satisfactorily arterial blood levels.

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