Changes in regional blood flow distribution and oxygen supply during hypoxia in conscious rats

1993 ◽  
Vol 74 (1) ◽  
pp. 211-214 ◽  
Author(s):  
I. Kuwahira ◽  
N. C. Gonzalez ◽  
N. Heisler ◽  
J. Piiper
Keyword(s):  
Blood Flow ◽  
Oxygen Supply ◽  
Regional Blood Flow ◽  
Acute Hypoxia ◽  
Peripheral Resistance ◽  
Respiratory Muscles ◽  
Flow Distribution ◽  
Aortic Blood Flow ◽  
Aortic Blood ◽  
O2 Concentration

The effects of acute hypoxia on central hemodynamics, regional blood flow, and regional oxygen supply (blood flow x arterial O2 concentration) were studied in conscious resting rats. Regional blood flow was determined by the radiolabeled microsphere technique. Blood pressure, heart rate; and aortic blood flow increased and total peripheral resistance decreased significantly during hypoxia. Blood flow to brain, respiratory muscles, and liver increased both in absolute value and as a fraction of the aortic blood flow. Fractional blood flow to the gastrointestinal tract, spleen, pancreas, skin, fat, and hindlimb bones decreased during hypoxia; blood flow decreased in absolute values only in stomach and fat. Oxygen supply to brain, respiratory muscles, and liver increased during hypoxia, whereas it decreased in the remaining organs investigated.

scholarly journals Changes in regional blood flow and pCO2 gradients during isolated abdominal aortic blood flow reduction

2003 ◽  
Vol 29 (12) ◽  
pp. 2255-2265 ◽  
Author(s):  
Rafael Knuesel ◽  
Stephan M. Jakob ◽  
Lukas Brander ◽  
Hendrik Bracht ◽  
Andreas Siegenthaler ◽  
...  
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Aortic Blood Flow ◽  
Flow Reduction ◽  
Aortic Blood ◽  
Blood Flow Reduction ◽  
Abdominal Aortic

Use of microspheres in measurement of regional blood flows during +GZ stress

1979 ◽  
Vol 47 (6) ◽  
pp. 1148-1156 ◽  
Author(s):  
M. H. Laughlin ◽  
J. W. Burns ◽  
F. M. Loxsom
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Aortic Pressure ◽  
Aortic Blood Flow ◽  
Miniature Swine ◽  
Blood Flows ◽  
Aortic Blood ◽  
High Acceleration ◽  
Regional Blood Flows ◽  
Aortic Blood Pressure

The use of the radiolabeled microsphere technique for the study of the effects of +GZ acceleration on regional blood flow is examined. A theoretical analysis of the limits of this technique in a high acceleration environment is presented. Chronically implanted, electromagnetic, aortic flow probes were used to determine the relationship between aortic blood flow velocity and +GZ acceleration in conscious adult miniature swine. It was found that conscious straining adult miniature swine, with the assistance of an inflated anti-G suit, are able to compensate quite well to acceleration levels less than or equal to +7 GZ. Exposure to +9 GZ often resulted in unstable cardiovascular states involving relative bradycardia, often progressing to asystole, declining aortic blood pressure, and markedly diminished cardiac outputs approaching zero. It was found that, if aortic pressure and heart rate attain a relatively steady state during acceleration, and if heart level mean aortic pressure is greater than or equal to 100 Torr, the application of the microsphere technique during +GZ acceleration is theoretically valid. This hypothesis was tested using the microsphere technique (9.0 +/- 0.8 microns diam) in conscious miniature swine during exposure to +GZ acceleration. It is concluded that within the defined limits the radiolabeled microsphere technique is as accurate for use during acceleration studies as it is for use in routine laboratory studies.

Sexual dimorphism in regional blood flow responses to vasopressin in conscious rats

1997 ◽  
Vol 273 (3) ◽  
pp. R1126-R1131 ◽  
Author(s):  
Y. X. Wang ◽  
J. T. Crofton ◽  
S. L. Bealer ◽  
L. Share
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Regional Blood Flow ◽  
Pressor Response ◽  
Peripheral Resistance ◽  
Female Rats ◽  
Sexually Dimorphic ◽  
Arterial Blood ◽  
Vasoconstrictor Response ◽  
Renal Vascular

The greater pressor response to vasopressin in male than in nonestrous female rats results from a greater increase in total peripheral resistance in males. The present study was performed to identify the vascular beds that contribute to this difference. Mean arterial blood pressure (MABP) and changes in blood flow in the mesenteric and renal arteries and terminal aorta were measured in conscious male and nonestrous female rats 3 h after surgery. Graded intravenous infusions of vasopressin induced greater increases in MABP and mesenteric vascular resistance and a greater decrease in mesenteric blood flow in males. Vasopressin also increased renal vascular resistance to a greater extent in males. Because renal blood flow remained unchanged, this difference may be due to autoregulation. The vasopressin-induced reduction in blood flow and increased resistance in the hindquarters were moderate and did not differ between sexes. Thus the greater vasoconstrictor response to vasopressin in the mesenteric vascular bed of male than nonestrous females contributed importantly to the sexually dimorphic pressor response to vasopressin in these experiments.

COMPUTATIONS OF PULSATILE AORTIC BLOOD FLOW PROBLEMS ON PARALLEL COMPUTERS

2003 ◽  
Vol 15 (03) ◽  
pp. 109-114
Author(s):  
YANG-YAO NIU ◽  
SHOU-CHENG TCHENG
Keyword(s):  
Blood Flow ◽  
Stokes Equations ◽  
Computing Time ◽  
Time Integration ◽  
Parallel Computer ◽  
Aortic Blood Flow ◽  
Pc Cluster ◽  
Flow Problems ◽  
Aortic Blood ◽  
Speed Up

In this study, a parallel computing technology is applied on the simulation of aortic blood flow problems. A third-order upwind flux extrapolation with a dual-time integration method based on artificial compressibility solver is used to solve the Navier-Stokes equations. The original FORTRAN code is converted to the MPI code and tested on a 64-CPU IBM SP2 parallel computer and a 32-node PC Cluster. The test results show that a significant reduction of computing time in running the model and a super-linear speed up rate is achieved up to 32 CPUs at PC cluster. The speed up rate is as high as 49 for using IBM SP2 64 processors. The test shows very promising potential of parallel processing to provide prompt simulation of the current aortic flow problems.

S-nitroso-albumin carries a thiol-labile pool of nitric oxide, which causes venodilation in the rat

2005 ◽  
Vol 289 (2) ◽  
pp. H916-H923 ◽  
Author(s):  
Nelson N. Orie ◽  
Patrick Vallance ◽  
Dean P. Jones ◽  
Kevin P. Moore
Keyword(s):  
Nitric Oxide ◽  
Molecular Weight ◽  
Blood Flow ◽  
Vascular Function ◽  
Low Molecular Weight ◽  
Aortic Blood Flow ◽  
Hemodynamic Effects ◽  
Rapid Decomposition ◽  
Aortic Blood

It is now established that S-nitroso-albumin (SNO-albumin) circulates at low nanomolar concentrations under physiological conditions, but concentrations may increase to micromolar levels during disease states (e.g., cirrhosis or endotoxemia). This study tested the hypothesis that high concentrations of SNO-albumin observed in some diseases modulate vascular function and that it acts as a stable reservoir of nitric oxide (NO), releasing this molecule when the concentrations of low-molecular-weight thiols are increased. SNO-albumin was infused into rats to increase the plasma concentration from <50 nmol/l to ∼4 μmol/l. This caused a 29 ± 6% drop in blood pressure, 20 ± 4% decrease in aortic blood flow, and a 25 ± 14% reduction of renal blood flow within 10 min. These observations were in striking contrast to those of an infused arterial vasodilator (hydralazine), which increased aortic blood flow, and suggested that SNO-albumin acts primarily as a venodilator in vivo. This was confirmed by the observations that glyceryl trinitrate (a venodilator) led to similar hemodynamic changes and that the hemodynamic effects of SNO-albumin are reversed by infusion of colloid. Infusion of N-acetylcysteine into animals with artificially elevated plasma SNO-albumin concentrations led to the rapid decomposition of SNO-albumin in vivo and reproduced the hemodynamic effects of SNO-albumin infusion. These data demonstrate that SNO-albumin acts primarily as a venodilator in vivo and represents a stable reservoir of NO that can release NO when the concentrations of low-molecular-weight thiols are elevated.

scholarly journals Effects of Dopamine and Dobutamine on Regional Blood Flow Distribution in the Neonatal Piglet

1995 ◽  
Vol 221 (5) ◽  
pp. 531-542 ◽  
Author(s):  
John J. Ferrara ◽  
D. Lynn Dyess ◽  
Guy L. Peeples ◽  
D. Paul Christenberry ◽  
W. Scott Roberts ◽  
...  
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Flow Distribution ◽  
Blood Flow Distribution ◽  
Neonatal Piglet
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