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PubMed1996

[Quantification of mesenteric flow with magnetic resonance imaging before and after a meal: results in healthy volunteers].

Several literature studies showed that total intestinal blood flow approximates superior mesenteric vein flow. Today, new accurate techniques can be used to measure blood flow. We investigated MR capabilities in measuring mesenteric vein flow, to assess total intestinal blood flow. Nine healthy volunteers were examined before and after a meal with a phase-contrast technique to measure blood flow. Flow speed and quantity can be measured positioning a ROI inside the vessel for speed evaluation and around the vessel for flow quantitation. Superior mesenteric blood flow exhibited a three-fold increase after a meal relative to pre-meal values. Cine phase-contrast MRI was a useful tool to measure mesenteric flow in healthy volunteers both before and after a meal and can therefore be suggested for the noninvasive examination of patients with a suspected chronic mesenteric blood supply deficiency.

Adult↗
PubMed2001

[Endoscopic aortofemoral bypass reconstruction: experimental and clinical results].

According to the present experiences, the new videoendoscopic vascular instrument systems have fulfilled the basic requirements for performing videoendoscopic aortoiliac surgery. The animal studies (n = 25) showed clearly, that the piglet is a reproducible and favourable model to acquire the basic surgical techniques for videoendoscopic aortoiliac surgery, since its retroperitoneal anatomy is similar to that of humans. The transabdominal-retroperitoneal approach on human cadavers (n = 6) was soon abandoned, since particularly in obese cases it caused burdensome sliding of the intestine into the operative field adjacent to the renal vessels. The intensive investigations on human cadavers (n = 20) has meanwhile allowed us to constantly expose the aorta above the inferior mesenteric artery up to the left renal vessels without the need to sacrifice the inferior mesenteric artery (total operating time: 3-4.5 hours, aortic reconstruction averagely 42 minutes). The prolonged operating time during the extraperitoneal approach, especially in case of accidental tearing of the retroperitoneum has led us to evaluate the transabdominal paracolic approach (n = 6). This procedure with right-sided positioning of the patient offers a broad operating area and retains the intestine in the right side of the abdomen throughout, thus reducing the operating time in our initial 6 cases to a mean of 2.9 hours (range: 2.5-3.5 hours). As to our limited clinical experience and in accordance to other surgical groups the video assisted aortoiliac surgery (n = 12) by performing a small abdominal incision for the aortic anastomosis under direct vision seems to be an alternative procedure to the total videoendoscopic aortoiliac surgery (n = 7). Further experimental research, consistent development and refinement of videoendoscopic vascular instruments and prospective evaluation of the different videoendoscopic approaches to the aortoiliac vessels are necessary to evaluate the use of the videoendoscopic surgical technique, to clarify its advantages and to probably generalize the procedure in the near future.

Aged↗
PubMed1991

Mesenteric blood flow in patients with diabetic neuropathy.

We examined flow velocities in the superior mesenteric artery and celiac artery in normal controls (group C, n = 11), diabetic patients (group D, n = 8), and diabetic patients with clinically evident autonomic neuropathy (group DN, n = 6) to further define the usefulness of duplex examination in the evaluation of the mesenteric circulation in normal and disease states. By use of a 3 MHz duplex scanner, peak systolic velocity, peak diastolic forward velocity, end-diastolic forward velocity, and peak diastolic reverse velocity were measured in centimeters per second before and after a standardized meal. The vessels' diameters in centimeters were also measured. After the meal peak diastolic reverse velocity disappeared in all patients. The average vessel diameter in the superior mesenteric artery (0.7 cm) and celiac artery (0.8 cm) did not change. Flow velocities in the celiac artery were not significantly altered by the meal. In the control group, peak systolic velocity in the superior mesenteric artery increased 38%, peak diastolic forward velocity rose 66%, and end-diastolic forward velocity increased by 70%. In the diabetic nonneuropathic group the changes were 15%, 98%, and 100%, respectively. These changes were statistically significant (p less than 0.01). On the other hand, the patients with diabetic autonomic neuropathy presenting a picture of gastroparesis did not exhibit the expected increases in postprandial velocities. Moreover, this alteration in blood flow velocity, although similar to that encountered in patients with intestinal angina, did not appear to be due to occlusive arterial disease on the basis of clinical examination and B-mode scanning.

Autonomic Nervous System Diseases↗
PubMed1995

Differential effects of phosphoramidon on contractile responses to angiotensin II in rat blood vessels.

1. Cumulative concentration-tension response (C-R) curves to angiotensin II (AII), big endothelin-1 (big ET-1), ET-1 and arginine vasopressin (AVP) were determined in endothelium intact-ring preparations of aorta, mesenteric artery and tail artery isolated from adult male Sprague-Dawley rats in the presence or absence of the neutral metalloprotease inhibitor, phosphoramidon. 2. The order of sensitivity of the three rat vascular smooth muscle preparations to AII, big ET-1 and ET-1 was aorta > mesenteric artery > tail artery whereas that for AVP was reversed, namely, tail artery > mesenteric artery > aorta. 3. Phosphoramidon blocked the responses to AII in a concentration-dependent manner, whereas even very high concentrations of phosphoramidon (100 microM) failed to affect the tension responses evoked by ET-1 and AVP in all three preparations. Low concentrations of phosphoramidon (10 microM) produced significant increases in EC50 values for AII in tail artery (P < 0.01) and mesenteric artery (P < 0.05) but not in aorta. The rank order of sensitivity to the inhibition by phosphoramidon was tail artery > mesenteric artery > aorta. Phosphoramidon-evoked rightward shifts in the C-R curves to AII were much higher than those to big ET-1 in both mesenteric artery and tail artery. 4. In endothelium-denuded preparations, AII failed to evoke any increases in tension in tail artery while the responsiveness of the mesenteric artery to AII was reduced significantly relative to endothelium-intact tissues with a rightward shift in the C-R curve and a decrease in the maximal response. On the other hand, the C-R curve to AII was shifted to the left in aorta following removal of the endothelium.Importantly, ET-1 and AVP evoked vasoconstrictor responses were unaffected by the inclusion of a high concentration of phosphoramidon (100 microM) in endothelium-denuded aorta and mesenteric artery.5. The results suggest that AII-evoked tension responses of blood vessels such as tail artery are completely endothelium-dependent; in relatively larger blood vessels such as mesenteric artery they are partially endothelium-dependent while in much bigger conduit type blood vessel such as aorta, they are endothelium-independent. It is concluded that the vasoconstrictor responses to AII in mesenteric artery and tail artery may be mediated by the release of endothelins from the endothelium by increased formation from big ET, an effect that is blocked by phosphoramidon.

Angiotensin II↗
PubMed2005

Altered endothelial function in isolated human myometrial vessels induced by plasma from women with pre-eclampsia is not reproducible in isolated mouse vessels.

In order to facilitate characterization of the circulating factor(s) in pre-eclampsia, the present study aimed to determine whether plasma from women with pre-eclampsia, which induces attenuated endothelial-dependent relaxation in human myometrial arteries, is also capable of inducing altered endothelial function in mouse vessels. Human vessels were isolated from myometrial biopsies taken from women with uncomplicated pregnancies (n = 6). Mesenteric and uterine arteries were isolated from male, female, non-pregnant and pregnant C57B mice (n = 24). Vessels were studied using a wire myograph and incubated with plasma (2%) from women with pre-eclampsia (n = 12) or controls (n = 12). Incubation of myometrial vessels from normal pregnant women with plasma from women with pre-eclampsia reduced endothelial-dependent relaxation. This effect was not reproduced in male or female mouse mesenteric or uterine vessels incubated with plasma from women with pre-eclampsia. In conclusion, there are species-specific differences in the actions of the circulating factor(s) on endothelial-dependent relaxation of human and mouse small arteries.

Adult↗
PubMed1995

Deoxycorticosterone acetate plus salt induces overexpression of vascular endothelin-1 and severe vascular hypertrophy in spontaneously hypertensive rats.

Endothelin-1 gene expression is enhanced in the aorta and mesenteric arteries, and possibly other vessels, of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. In contrast, endothelin-1 gene expression is normal or reduced in spontaneously hypertensive rats (SHR). Severe vascular hypertrophy is present in DOCA-salt hypertensive rats but not in SHR. In this study we investigated whether treatment of SHR with DOCA and salt would result in enhanced endothelin-1 expression and at the same time in severe vascular hypertrophy. Increased abundance of endothelin-1 mRNA was found in the aorta and the mesenteric arterial bed of SHR treated simultaneously with DOCA and salt but not when rats were treated with either separately. The wet weight of the aorta and of the mesenteric arterial bed, media thickness, media cross-sectional area, and media-to-lumen ratio of mesenteric small arteries of DOCA-salt-treated SHR were exaggerated beyond what could be explained by the elevation of blood pressure, relative to SHR treated with salt or with DOCA, which did not overexpress vascular endothelin-1. In conclusion, SHR may exhibit enhanced expression of the endothelin-1 gene in blood vessels when treated with DOCA and salt, and associated with this there is severe vascular hypertrophy. These data support the hypothesis of a role of endothelin-1 in vascular hypertrophy.

Animals↗
PubMed1987

Variations in rat mesenteric tissue thickness due to microvasculature.

Studies of microvascular, tissue and lymphatic transport using microphotometric and microfluorometric techniques are potentially subject to artifact due to variations in tissue specimen thickness. Absorbance techniques utilize the Lambert-Beer law in which A = log I0/I = act, where A is absorbance, I0 is incident light intensity, I is transmitted intensity, a is an absorbance coefficient, c is concentration of substance, and t is path length. If differences in t are known to be present, then inferences of changes in c from changes in A become suspect. In microfluorometry the amount of light gathered is proportional to the number of fluorochromes in the effective cuvette, which is determined by the microscope's numerical aperture and the sample thickness. If variations in thickness are known to occur, the effective cuvette volume may be changing; therefore, inferences of changes in fluorochrome concentration from changes in intensity become suspect. Existing data suggest that rat mesentery is 15-30 microns thick, but variation over a tissue region is unknown. Our goals are to determine thickness variation in avascular, fat-free mesenteric tissue regions; thickness variation near blood vessels; and average tissue thickness. Sprague-Dawley rats were anesthetized with Inactin. Mesenteric tissue from a loop of small intestine was draped over a platform for observation; thickness was measured with an oblique microscope and a microgravimetric technique. The average variation in avascular fat-free tissue was 1.1 micron/100-microns distance, and average thickness was 17.4 microns. There was a significant increase in thickness over the microvasculature.

Animals↗
PubMed1997

Mesenteric revascularisation for acute-on-chronic intestinal ischaemia.

Eleven patients (eight women) underwent urgent revascularisation for acute-on-chronic mesenteric ischaemia. Four patients had dual vessel and seven single vessel reconstructions. Two patients underwent simultaneous bowel resection and one patient has had three separate grafts to the superior mesenteric artery. There were two peri-operative deaths and three have died in the late follow-up period after 18, 24 and 36 months. The remainder have survived for between five and 63 months. Revascularisation for acute-on-chronic mesenteric ischaemia has been shown to be technically possible and of substantial benefit to patients who would otherwise be treated as terminal cases.

Acute Disease↗
PubMed1996

Postprandial splanchnic hemodynamic response in patients with cirrhosis of the liver: evaluation with "triple-vessel" duplex US.

PURPOSE: To investigate the effect of a meal on splanchnic circulation in patients with cirrhosis of the liver. MATERIALS AND METHODS: Ten adult patients with cirrhosis and 10 adult control subjects (mean age, 54 years) underwent duplex ultrasonography. Flow volumes of the portal vein, superior mesenteric artery, splenic artery, and collateral vessels (difference between the splanchnic inflow [the sum of the superior mesenteric arterial and the splenic arterial blood flows] and the portal venous blood flow) were measured before and after a meal every 15 minutes for 60 minutes. Integrated post-prandial changes (the sum of the changes at each time point) were also calculated. RESULTS: Portal venous blood flow increased after the meal in control subjects (P < .01) and patients (P < .01). The integrated postprandial change in the portal venous blood flow was lower in patients than in control subjects (P < .05). Superior mesenteric arterial blood flow increased after the meal in control subjects (P < .01) and patients (P < .01); the integrated postprandial change in the superior mesenteric arterial blood flow was similar. In the two groups, splenic arterial blood flow remained unchanged after the meal. Collateral blood flow increased after the meal in patients (P < .01). CONCLUSION: Postprandial portal hyperemia is mainly due to mesenteric arterial vasodilation; reduced postprandial portal hyperemia in patients with cirrhosis is attributable to portocollateral runoff.

Adult↗
PubMed1998

Effect of the NO scavenger carboxy-ptio on endothelium-dependent vasorelaxation of various blood vessels from rabbits.

In the present study, we investigated the effect of a nitric oxide (NO) scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide [carboxy-PTIO], on endothelium-dependent relaxation of a series of blood vessels from rabbits, such as thoracic aorta and femoral, renal, mesenteric, and pulmonary arteries, using a functional muscle bath technique. Carboxy-PTIO produced concentration-dependent contractions in various vessels. The contractile responses in renal, mesenteric, and pulmonary arteries were significantly greater than those in the aorta and femoral artery. Similarly, phenylephrine-induced contractions in renal, mesenteric, and pulmonary arteries were markedly enhanced after pretreatment with carboxy-PTIO. Also, carboxy-PTIO inhibited acetylcholine-induced relaxation in various blood vessels. The maximum inhibitions in aorta and femoral artery were significantly greater than those in renal, mesenteric, and pulmonary arteries. The present data demonstrate that carboxy-PTIO reduces basal, phenylephrine-, and acetylcholine-induced release of NO in rabbit blood vessels. However, different degrees of inhibition of endothelium-dependent vasorelaxation were observed in various vessels. Specifically, the thoracic aorta and femoral artery are less susceptible to the action of carboxy-PTIO without acetylcholine than renal, mesenteric, and pulmonary arteries. Conversely, the most potent carboxy-PTIO-induced inhibition of acetylcholine-induced vasorelaxation was observed with aorta and femoral arteries. Thus, it is suggested that the contribution of endogenous NO to vascular tone and regional blood flow may vary among different rabbit blood vessels.

Acetylcholine↗
PubMed1999

Increased nitric oxide concentrations in posterior hypothalamus and central sympathetic function on nitrate tolerance following subcutaneous nitroglycerin.

The present study was to examine the distributions of nitric oxide (NO) in the brain regions and peripheral vessels following subcutaneously administered nitroglycerin (NTG) and determine the noradrenergic activity and the role of central sympathetic function in acute nitrate tolerance. Tolerance to NTG was produced by subcutaneous (sc) administration of 4.0 mg NTG as four separate hourly pulse injections of 1.0 mg each in male (5-8 months) Sprague-Dawley rats. Rats in sham-treated group received sc injections of saline. Rats were killed by sodium pentobarbital (150 mg/kg, ip) at 10 min after last sc injection. The brain, gracilis muscle, aorta, superior mesenteric artery, coronary artery, and pulmonary vessels were quickly removed. Concentrations of nitrite (NO2-), nitrate (NO3-), and total NO2- plus NO3- (NOx-) were quantified in the micropunches of the anterior hypothalamus, the posterior hypothalamus (PH), the nucleus tractus solitarius, the lateral reticular nucleus, and the vessels in a blinded fashion. The central actions of acute tolerance to NTG were also determined using blockades of sympathetic functions in conscious rats. Four separate hourly pulse sc injections of 1.0 mg NTG produced a marked shift of the dose-response curve for arterial pressure depression induced by intravenous injection of the challenge doses of NTG. The same doses of sc NTG caused increases in NOx- [92+/-16% (mean +/- SE)] and NO3- productions (77+/-15%) in the PH, but did not significantly change in other brain regions (n = 6). NOx- and NO3- productions were significantly enhanced in the superior mesenteric artery, aorta, coronary artery, and pulmonary vessels following sc NTG, but were not altered in gracilis muscle by the treatment. The tolerance responses to arterial pressure depression were attenuated by intravenous administration of either prazosin (300 microg/kg), an alpha1-adrenoceptor antagonist, or chlorisondamine (10 mg/kg), a sympathetic ganglion blockading agent (n = 5-6). The results suggest that acute NTG tolerance predominately increases NO production in the PH. NO production was also markedly enhanced in the large and middle vessels but not in small vessels during acute NTG tolerance. The arterial pressure tolerance to NTG was reversed by blockade of central sympathetic function. We conclude that NO formation is increased in the PH following systemically administered NTG and NO in the PH may facilitate central sympathetic functions which contribute to nitrate tolerance.

Animals↗
PubMed1997

Segmental arterial mediolysis studied by repeated angiography.

Segmental arterial mediolysis (SAM) is a rare disease of unknown aetiology. We report the fourteenth case of SAM, but the first to demonstrate serial changes on arteriography. A 65-year-old woman with abdominal pain underwent laparotomy with resection of an abnormally beaded and narrowed segment of the right branch of the middle colic artery. Characteristic pathological findings of lysis of the arterial media with dissecting haematomas were present. Other than some post-prandial pain, the patient's post-operative course was uneventful. Serial arteriography showed various abnormalities in the trunk and branches of the superior mesenteric artery. Changes in the vessels consisted of three phases, i.e. dilatation, beading with narrowing and restoration of the smooth wall, with various modifications such as aneurysmal enlargement and occlusion.

Aged↗
PubMed1990

[Mitotic activity of the endothelium of different-diameter blood microvessels in the mesentery of Wistar rats].

The technique of intravascular autoradiography of 3H-thymidine labeled nuclei of microvessels endothelia was developed. The density difference of labeled cells in microvascular bed of mesentery was estimated. The maximal density of labelled nuclei was found in pre- and postcapillary vessels, and minimal--in capillaries and large arteries and veins of mesenteric bed. The number of labeled nuclei per vessel was found to be relatively constant. The density of labeled cells in 4-months old rats is less than that in 3 weeks-old ones.

Age Factors↗
PubMed1989

Sympathetic innervation of the reproductive organs of the male opossum, Didelphis albiventris (Lund, 1841).

The dissection of nerves and ganglia anatomically related to the pelvic organs revealed one inferior mesenteric ganglion, two testicular ganglia, two hypogastric nerves, two pelvic ganglia and two pelvic nerves. The histochemical demonstration of catecholamines by a glyoxylic acid fluorescence method revealed a rich sympathetic innervation in the ductus deferens, in the three segments of the prostate and in the convoluted ductuli efferentes. The testis, epididymis and all three pairs of bulbourethral glands presented fluorescent nerve fibers only around blood vessels. Removal of the inferior mesenteric and testicular ganglia, and hypogastric neurectomy with our without ligature and sectioning of testicular arteries, had no effect on the density of the nonvascular fluorescent fibers. Removal of the periprostatic tissue caused complete denervation of the prostate and marked denervation of the ductuli efferentes and ductus deferens. Small ganglia containing fluorescent nerve cell bodies were found close to the capsule of the prostate. The results indicate that short adrenergic neurons are responsible for the sympathetic innervation of the reproductive organs of the male opossum.

Animals↗
PubMed1994

Perfluoroctyl bromide as a blood pool contrast agent for computed tomographic angiography.

RATIONALE AND OBJECTIVES: We determined whether perfluoroctyl bromide (perflubron) could be used as a computed tomography (CT) angiographic agent by studying vessel visibility (celiac artery, superior mesenteric artery [SMA], and renal arteries) with spiral CT and three-dimensional (3D) reconstructions. METHODS: Five rhesus monkeys were examined with a perflubron emulsion (90% [w/v] perfluorochemical; administered intravenously at a dose of 1.5 ml/kg and at a rate of 0.5 ml/sec. Spiral CT was performed immediately and at 5 hr after injection. Three dimensional images of the aorta at the level of the celiac artery, SMA, and renal arteries were reconstructed and blindly rated 0-4 (0 = not seen; 4 = excellent visualization) by two observers. RESULTS: All the vessels had the best ratings immediately after injection: celiac artery, 2.8 +/- 0.42; SMA, 2.7 +/- 0.48; left renal artery, 2.1 +/- 0.99; and right renal artery, 1.2 +/- 1.03. The ratings after the 5-hr delay were as follows: celiac artery, 1.3 +/- 1.34; SMA, 1.5 +/- 1.08; left renal artery, 1.5 +/- 0.97; and right renal artery, 1.2 +/- 0.79. CONCLUSIONS: Spiral CT angiography with a perflubron emulsion successfully demonstrated all vessels immediately and at 5 hr after contrast agent infusion. Further refinements of the dose, rate, and reconstruction technique are expected to increase vessel visibility over this wide imaging window.

Angiography↗
PubMed1999

[Neuronal control of mesenteric circulation].

The mesenteric circulation plays an important role in maintenance of systemic blood pressure and regulation of tissue blood flow. The tone of the mesenteric artery and resistance blood vessels are mainly regulated by sympathetic adrenergic nerves through the release of neurotransmitter noradrenaline and also controlled by nonadrenergic noncholinergic (NANC) nerves and possibly by parasympathetic cholinergic nerves. Noradrenaline and adrenergic cotransmitters including neuropeptide Y and adenosine triphosphate act as a vasoconstrictor neurotransmitter for sympathetic nerves. While, dopamine, calcitonin gene-related peptide and acetylcholine act as a vasodilator neurotransmitter for adrenergic, NANC and cholinergic nerves, respectively. In the mesenteric circulation, these nerves containing various neurotransmitters and cotransmitters interact and modulate each other via feedback autoregulatory mechanisms and neuromodulation of various vasoactive substance to regulate vascular resistance.

Animals↗
PubMed1975

[Effect of strophanthin on intestinal blood flow. A contribution to the physiopathology of hemorrhagic enteropathy].

The purpose of the present study was to compare in canine experiments hemodynamic and angiographic effects on mesenteric circulation. I. v. administration of strophanthin is leading to an increase of arterial pressure and a decrease of mesenteric blood flow. Most consistent angiographic changes are attenuation and local vasoconstriction of peripheral vessels. The relationship between digitalis administration and mesenteric underperfusion leading to non-occlusive mesenteric ischemia is discussed.

Animals↗