Neonatal intestinal circulation

2011 ◽  
Author(s):  
Philip T. Nowicki
Keyword(s):  
Intestinal Circulation

Effects of nicotine on canine intestinal blood flow and oxygen consumption

1984 ◽  
Vol 246 (2) ◽  
pp. G195-G203
Author(s):  
R. H. Gallavan ◽  
Y. Tsuchiya ◽  
E. D. Jacobson
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Muscle Tension ◽  
Intestinal Blood Flow ◽  
Mesenteric Blood Flow ◽  
State Response ◽  
Arterial Blood ◽  
Intestinal Circulation

The purpose of this study was to determine the effects of nicotine on intestinal blood flow and oxygen consumption. The intravenous infusion of nicotine at doses corresponding to those experienced by smokers produced a transient increase in systemic arterial blood pressure and mesenteric blood flow. Subsequently a steady-state response developed that consisted of a reduction in mesenteric blood flow due to both a decrease in blood pressure and an increase in intestinal vascular resistance. This increase in resistance was probably due to increased levels of circulating catecholamines. The intra-arterial infusion of nicotine into the intestinal circulation at doses experienced by the average smoker had no effect on either intestinal blood flow or oxygen consumption. Similarly, under in vitro conditions nicotine had no direct effect on intestinal vascular smooth muscle tension. Thus, nicotine appears to reduce intestinal blood flow indirectly as a result of its systemic effects.

Effects of desflurane on the pig intestinal circulation during hypotension

1999 ◽  
Vol 43 (10) ◽  
pp. 1069-1077 ◽  
Author(s):  
H. Sundeman ◽  
A. Åneman ◽  
M. Broomé ◽  
M. Haney ◽  
G. Johansson ◽  
...  
Keyword(s):  
Intestinal Circulation

Partial analysis of segmental resistances in intestinal vessels after endotoxin

1962 ◽  
Vol 202 (5) ◽  
pp. 913-918 ◽  
Author(s):  
Maurice W. Meyer ◽  
Maurice B. Visscher
Keyword(s):  
Lethal Dose ◽  
Wall Tension ◽  
Shock State ◽  
E Coli ◽  
Small Vessels ◽  
Control Value ◽  
Partial Analysis ◽  
Subsequent Rise ◽  
Venous Segment ◽  
Intestinal Circulation

Hemodynamic responses of intestinal vascular segments of the dog to intravenous administration of a lethal dose (1 mg/kg) of E. coli endotoxin were investigated. Pressures were measured in large and small vessels of the intestinal and mesentery (small veins 30–60 µ in radius). Vascular radii of submucosal vessels and blood flow were determined. Changes in total resistance in the intestinal circulation after endotoxin were not uniform during the first few minutes, but there was a significant decrease at 10 min and a subsequent rise to the control value after 1 hr. At both 50 and 60 min, the resistance was increased over control in the arterial segment by 50%, increased 500% in the venous segment, and decreased 40% in the segment from small artery to venule. These circumstances would increase capillary pressure and filtration of edema fluid. Increased wall tension at reduced diameter developed in the venous segment during the secondary shock state, whereas relaxation of wall tension occurred in the arteriolar segment.

Autoregulatory escape from vasoconstriction of intestinal circulation in developing swine

1987 ◽  
Vol 252 (1) ◽  
pp. H118-H124 ◽  
Author(s):  
N. M. Buckley ◽  
M. Jarenwattananon ◽  
P. M. Gootman ◽  
I. D. Frasier
Keyword(s):  
Nerve Stimulation ◽  
Control Level ◽  
Splanchnic Nerve ◽  
Adrenergic Nerve ◽  
Vasoconstrictor Response ◽  
Mean Pressure ◽  
Functional Immaturity ◽  
Autoregulatory Escape ◽  
Infusion Of Norepinephrine ◽  
Intestinal Circulation

The capability of the developing intestinal circulation to maintain a vasoconstrictor response during postganglionic adrenergic nerve stimulation or norepinephrine infusion was examined in 34 swine aged 6 h to 2 mo anesthetized with pentobarbital sodium. Aortic and portal venous pressures, electrocardiogram (ECG), and blood flow (F) through the superior mesenteric artery were recorded, and intestinal vascular resistance (MVR) was calculated as mean pressure difference per mean F. Baroreceptor reflex inhibition by bilateral occlusion of the carotid arteries increased MVR, section of the splanchnic nerve and postganglionic fibers decreased MVR, and short-latency F decreases were obtained during mesenteric nerve stimulation (MNS). Latencies for the decreases in F shortened with age and with increasing MNS frequency (5–17 Hz) at any age. Prolonging MNS for 60 s at 10 or 12 Hz led to sustained high MVR in 6-h to 7-day-old animals; however, MVR decreased toward control before the end of the 60-s MNS period in animals 1 to 2 mo old. Intra-arterial infusion of norepinephrine (0.5 microgram X kg-1 X min-1) decreased F and increased MVR in all animals; but by 5 min of infusion, F was returning toward control level in all but the youngest. This demonstration that the least mature intestinal circulation was least capable of autoregulatory escape from vasoconstriction provides further evidence of its functional immaturity.

Microsphere passage through intestinal circulation: via shunts or capillaries?

1985 ◽  
Vol 248 (2) ◽  
pp. H217-H224 ◽  
Author(s):  
L. C. Maxwell ◽  
A. P. Shepherd ◽  
C. A. McMahan
Keyword(s):  
Frequency Distribution ◽  
Probabilistic Models ◽  
Venous Blood ◽  
Sphere Diameter ◽  
Frequency Distributions ◽  
Flow Through ◽  
Pass Through ◽  
Intestinal Circulation ◽  
Sieving Effect

Significant quantities of 9-micron microspheres (20-30%) are not trapped in the intestine following intracardiac or intra-arterial injection, but reach venous blood. Some investigators propose that the passage of 9-micron spheres measures blood flow through noncapillary connections. Because frequency distributions of intestinal capillary diameters and 9-micron spheres overlap, microspheres could simply pass through capillaries. Therefore, we developed simple probabilistic models to predict both the size distribution and the percentage of injected spheres [9 +/- 1 (SD) micron] that should appear in venous blood. Chief assumptions in models are that microsphere delivery and sphere diameter are independent and that microspheres pass through capillaries of equal or larger size. The passage predicted by the models was consistent with values in canine intestinal circulation, demonstrating that passage through capillaries [7.38 +/- 1.4 (SD) micron] adequately accounts for spheres in venous blood. Because the diameters of nominal 9-micron spheres were distributed too narrowly to show a marked sieving effect on passage through the intestinal circulation, we also injected microspheres varying from 5 to 20 micron in diameter. This mixture demonstrated a marked sieving effect. The predicted frequency distribution for microsphere diameters in venous blood agreed with the observed distribution. Our models demonstrate that the passage of 9-micron spheres through capillaries, rather than through “shunts,” adequately accounts for the appearance of spheres in venous blood and suggests that the frequency distribution of venous microspheres can provide an in vivo method for estimating the frequency distribution of intestinal capillary diameters.

Intestinal Circulation in Coeliac Disease: an Angiographic Study

1982 ◽  
Vol 17 (7) ◽  
pp. 881-885 ◽  
Author(s):  
T. Gustafson ◽  
K. Sjölund ◽  
N.-O. Berg
Keyword(s):  
Coeliac Disease ◽  
Angiographic Study ◽  
Intestinal Circulation
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