Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MESENTERIC VESSELS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,459 records · Page 81Linked to original sources
PubMed1991

Mesenteric vascular responses of young spontaneously hypertensive rats.

Frequency-responses curves for nerve stimulation and dose-response curve for norepinephrine, 5-hydroxytryptamine potassium chloride, vasopressin and acetylcholine (ACh) were determined in isolated, perfused mesenteric vascular beds from young (approximately 5 weeks) spontanelouly hypertensive (SHR) and Wistar Kyoto rats. Although mean systolic blood pressure (measured by tail cuff plethysmography) was slightly higher in the SHR, this difference was not significant. Slopes and maximum responses were increased significantly for nerve stimulation and all agonists. The basal perfusion pressure was also significantly elevated in the SHR. These differences are consistent with existing evidence that structural changes occur in blood vessels of SHR at an early stage and probably precede development of hypertension. Such structural changes could therefore contribute to development of the hypertension. Cocaine (1 microM) markedly increased responses to nerve stimulation and bolus injections of norepinephrine in preparations from SHR with little or no effect on such responses in Wistar Kyoto preparations, a result consistent with the known greater density of noradrenergic nerves in SHR vasculature. In the presence of cocaine, there was unmasked a selective super-sensitivity (significantly lower ED50) to norepinephrine in the SHR. Thus SHR mesenteric vessels may possess an alteration in adrenoreceptors or their coupling to other cellular mechanisms. Responses to ACh revealed no indication of a deficient endothelial mediated relaxation. An altered media:lumen ratio of small arteries, hypernoradrenergic innervation and supersensitivity to the transmitter may contribute to development of hypertension.

Animals↗
PubMed1994

Drug-induced endothelium-dependent and -independent relaxations in isolated resistance vessels taken from simultaneously hypertensive and streptozotocin-diabetic rats.

Hypertension and diabetes mellitus often co-exist and both conditions may be expected to cause synergistic vascular damage. Our group has introduced an animal model for simultaneously occurring hypertension and diabetes mellitus by treating spontaneously hypertensive rats with streptozotocin (STZ). We investigated the drug-induced endothelium-independent and -dependent relaxation in isolated mesenteric small arteries (resistance vessels). Concerning the influence of hypertension, the responses to sodium nitroprusside, methacholine, histamine and nifedipine proved unchanged, the vasodilator response to bradykinin was diminished, whereas that to the K(+)-channel opener cromakalim was enhanced. With respect to the influence of STZ-induced diabetes we found that the responses to sodium nitroprusside, methacholine and nifedipine were unchanged, and that to cromakalim was enhanced, also when the preparations were pretreated with glibenclamide. The responses to histamine (STZ WKY versus control WKY) and bradykinin (STZ SHR versus control SHR) proved enhanced in the isolated vessels taken from diabetic animals. These findings suggest that the influence of the diabetic state is more pronounced than that of hypertension. However, our findings do not indicate that either hypertension or diabetes is associated with generalised endothelial damage in the resistance arteries.

Animals↗
PubMed1990

Protamine and mast-cell-mediated angiogenesis in the rat.

Different doses of protamine sulphate (PS) given s.c. (at 12-h intervals) were tested for signs of non-specific toxicity measured as effect on body weight and small-gut proliferation as well as on mast-cell secretion and mast-cell-mediated mitogenesis in the mesenteric windows following i.p. injection of Compound 48/80, a potent mast cell secretagogue, in normal rats. In a non-toxic dose range, the effect of PS on mast-cell-mediated angiogenesis, effected by 48/80, was quantified as the number of vessels per mm of mesenteric window in histological sections at x 400. No intelligible dose-effect relationship was discernible between the dose of PS given and the effect on angiogenesis. Only in a tight interval, at 40 mg PS/kg but not at 20 or 60 mg PS/kg, was the angiogenesis statistically significantly suppressed. Hence, it was concluded that PS can be angiostatic but does not exert a more general angiostatic effect in the autogenous systems used.

Animals↗
PubMed2006

Ischemia/reperfusion-induced low reactivity of the rat superior mesenteric vascular bed is associated with expression of nitric oxide synthases.

UNLABELLED: Our objective was to investigate the mRNA and protein expressions of eNOS and iNOS in the mesenteric vascular bed after ischemia and reperfusion of the rat superior mesenteric artery (SMA) and the role of nitric oxide (NO) in the response of the vascular bed to vasoconstrictors following reperfusion of the SMA. METHODS: Real-time polymerase chain reaction and immunohistochemistry were used to monitor the mRNA and protein expression of eNOS and iNOS after I/R challenge to the rat SMA. Ischemia was induced by clamping the SMA for 40 minutes, after which the flow was restored and the vessels were reperfused for 300 minutes. Blood samples were collected for assays of lactic dehydrogenase, tumor necrosis factor (TNF), hydroxyl radical, and NO. After ischemia/reperfusion, the vascular beds were separated for analysis of the expression of eNOS and iNOS. The SMA with its associated intestinal tissue was isolated and perfused in vitro with Tyrode's solution (N = 8) then challenged with phenylephrine. RESULTS: Reperfusion of the SMA induced an increase in blood concentrations of lactic dehydrogenase (P < .001; N = 8), hydroxyl radical (P < .05), TNF (P < .001), and NO (P < .05). ENOS and iNOS mRNA expression increased 1.3 +/- 0.1-fold and 19.6 +/- 3.5-fold, respectively when compared to the sham-operated group. Protein expression increased 1.9 +/- 0.4-fold and 12.6 +/- 3.1-fold, respectively, after reperfusion (N = 3) when compared with sham-treated rats. In vitro challenge showed that administration of phenylephrine (10(-8) approximately 10(-4) nmol) produced vasoconstriction in a dose-related manner. Maximum contractile responses to phenylephrine were attenuated in reperfused SMA. Addition of the NOS inhibitor N(G)-nitro-L-arginine (L-NNA, 10(-4) M) resulted in full recovery of the response to phenylephrine. CONCLUSIONS: Ischemia/reperfusion of the SMA results in a decrease in vascular reactivity of the mesenteric vessels that is dependent on NOS expression by the intestinal vascular bed.

Animals↗
PubMed1980

[Sex characteristics of the anatomy of the superior mesenteric lymph nodes in an adult].

In 60 corpses of grown-up persons at the age of 21-90 years the number, size and form of the superior mesenteric lymph nodes and their vessels have been investigated. The lymph nodes in question, their afferent and deferent vessels have been revealed by means of interstitial injection of coloured masses into the small intestine wall, and subsequent injection of the lymph nodes situated in the mesentery. Certain sex differences have been revealed in the number, size and form of the superior mesenteric lymph nodes and their vessels.

Adult↗
PubMed2001

Endovascular stent-graft in abdominal aortic aneurysms: the relationship between patent vessels that arise from the aneurysmal sac and early endoleak.

PURPOSE: To determine the association of patent sac branch vessels (lumbar and inferior mesenteric arteries [IMAs]) with early endoleak rate after stent-graft repair of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: Pre- and postoperative computed tomographic (CT) angiograms in 158 patients who underwent stent-graft AAA repair were retrospectively reviewed to determine the preoperative patency of IMAs and other sac branch vessels (feeders) and presence or absence of immediate postoperative endoleak. Relationships of early endoleak rate with total branch vessel, IMA, and lumbar artery patency and graft type were evaluated. RESULTS: There was a significant association between patency of sac feeders and rate of early endoleak, especially type 2. As total patent feeders increased from zero to three to four to six, total endoleak rate increased from 6% (one of 17) to 35% (30 of 86); type 2 endoleak rate, from 0% to 25%. IMA patency was significantly associated with total early endoleak rate. Increasing lumbar artery patency also was associated with significantly higher total and type 2 endoleak rates: With zero to three lumbar arteries, the total endoleak rate was 17% and type 2 endoleak rate was 13%, as compared with 60% and 50%, respectively, with more than six patent lumbar arteries. CONCLUSION: Sac branch vessel patency is associated with significantly higher early total and type 2 endoleak rates after stent-graft repair of AAAs; thus, patent sac branches play an important role in the pathogenesis of endoleaks.

Aged↗
PubMed1997

KCa-channel blockade prevents sustained pressure-induced depolarization in rat mesenteric small arteries.

In small blood vessels, elevation of transmural pressure induces myogenic constrictions and smooth muscle depolarization. The role of calcium-activated K+ channels (KCa channels) in these responses was examined in cannulated rat mesenteric small arteries. Inner and outer diameter were continuously monitored with a video technique. Smooth muscle membrane potential was recorded simultaneously using microelectrodes. To test for myogenic responsiveness, the transmural pressure was changed stepwise in the range between 10 and 120 mmHg. Pressure elevation induced moderate myogenic responses and significant depolarization, from -54.5 +/- 0.4 (SE) mV (n = 56) at 10 mmHg to -47.3 +/- 1.8 mV (n = 12) at 120 mmHg. Norepinephrine (NE, 0.67 and 10 microM) induced constriction and vasomotion, augmented myogenic responsiveness, and shifted the pressure-membrane potential relation to more depolarized values. Blockade of the Kca channels with charybdotoxin (ChTX) suppressed the responsiveness to pressure. In the absence of ChTX, with 0.67 microM NE, pressure elevation from 10 to 120 mmHg induced depolarization from -46.9 +/- 1.0 (n = 16) to -35.8 +/- 0.7 (n = 12) mV, whereas because of the myogenic response, the diameter increased only by 7%. In the presence of ChTX, with 0.3 microM NE, pressure changed the membrane potential from -41.0 +/- 1.1 (n = 12) to -37.8 +/- 0.7 mV (n = 4), which was not significant, and the diameter increased by 28%. These results demonstrate that blockade of KCa channels reduces responsiveness to pressure elevation. This suggests that pressure may induce depolarization and concomitant myogenic responsiveness by closure of KCa channels.

Animals↗
PubMed1986

Chronic intestinal ischemia: diagnosis and therapy.

Splanchnic arteriosclerosis is common among the elderly population, but intestinal angina is distinctly a rare entity. Extensive and efficient mesenteric collateral pathways make development of intestinal angina unlikely unless at least two major vessels exhibit hemodynamically important stenoses. Herein we describe the surgical management of 17 patients with chronic intestinal ischemia. The patients most commonly had postprandial pain and lost significant weight; angiography, including lateral aortography, confirmed the diagnosis. An average of 2.5 vessels in these 17 patients were arteriosclerotically involved. These 17 patients underwent 20 major splanchnic artery reconstructions altogether (average, 1.2 vessels per patient) for relief of symptomatic intestinal ischemia. Arterial reconstructions (16 bypass procedures and 4 endarterectomies) were undertaken with either autogenous saphenous vein (10 vessels) or Dacron prosthetics (6 vessels). Revascularizations involved the superior mesenteric artery (six patients), hepatic artery (three patients), splenic artery (seven patients), and inferior mesenteric artery (four patients). Five deaths occurred after operation, two early and three late, all from myocardial infarctions. All patients who survived have been relieved of their pain, and there has been no recurrence. The average length of follow-up has been 60.9 months and repeat angiography in six patients at intervals of up to 5 years has shown no evidence of revascularization occlusion.

Aged↗
PubMed1976

[Gastro-duodenal artery arising from the superior mesenteric artery].

These exceptional anomalies of the gastro-duodenal (G.D.) arteries provide a better understanding of certain very odd vessels found on coeliac or superior mesenteric arteries selective arteriography. In our series of 400 dissected bodies, a typical origin of the G.D. artery from the superior mesenteric artery is noted in 4 cases : the aberrant vessel is identified as a G.D. artery because of a) its course, b) and its two usual terminal divisions : superior pancreatico-duodenal and right gastro-epiploic arteries. On the other hand, we have 10 cases of G.D. artery arising from both coeliac hepatic and superior mesenteric arteries with:--a dominant hepatic branch in 6,--a dominant mesenteric branch in 3,--and a balanced origin in 1. A G.D. artery looping around the common bile duct to reach the anterior surface of the pancreas (Michels) was never seen in this series.

Duodenum↗
PubMedDate not supplied

Chronic nitric oxide inhibition aggravates hypertension in erythropoietin-treated renal failure rats.

Alterations in nitric oxide (NO) and endothelin-1 (ET-1) production have recently been reported in erythropoietin (r-HuEPO)-induced hypertension in renal failure rats. The present study was designed to evaluate the effect of NO synthase inhibition with the L-arginine analog NG-nitro-L-arginine methyl ester (L-NAME) on blood pressure (BP) and ET-1 production in control and in uremic rats treated or not treated with r-HuEPO. Renal failure was induced by a two-stage 5/6 nephrectomy. Control and uremic rats were studied separately and subdivided into four groups: vehicle, r-HuEPO, L-NAME + vehicle and L-NAME + r-HuEPO. L-NAME (100 mg/kg/day), r-HuEPO (100 U/kg, subcutaneously, three times per week), the vehicle or both were administered during 4 weeks in control rats and during 2 weeks in uremic rats. Systolic BP was recorded before and after the onset of treatment at weeks 2 and 4 in control rats and at weeks 1 and 2 in uremic rats. Hematocrit, serum creatinine, plasma, blood vessel (thoracic aorta and mesenteric artery bed) and renal cortex immunoreactive (ir) ET-1 concentrations were measured at the end of the protocol. L-NAME enhanced BP in control and uremic rats and the increase was significantly higher in uremic rats under r-HuEPO therapy (222 +/- 7 mmHg vs 198 +/- 6 mmHg, p<0.05). L-NAME induced an increase in thoracic aorta ir-ET-1 concentrations in control and uremic rats. In contrast, ir-ET-1 concentrations were unchanged in the mesenteric arterial bed and the renal cortex of control and uremic animals. R-HuEPO increased thoracic aorta ir-ET-1 contents in L-NAME treated control and uremic rats. These results underline the important role of NO release in opposing the action of vasopressors on blood vessel tone which appears more important in uremic rats treated with r-HuEPO. L-NAME treatment increased large vessel, but not small resistance artery ir-ET-1 concentrations, suggesting differential regulation of ET-1 production in different vascular beds under chronic NO synthase inhibition.

Animals↗
PubMed1981

Actions on the cardiovascular system of an inhibitory material extracted from the bovine retractor penis.

1 A partially purified material has been isolated from methanol extracts of the bovine retractor penis muscle. This material exerts biological activity only after treatment with acid and subsequent neutralisation. The active principle in this extract, which appears to be no known autacoid, mimics the response to stimulation of the non-adrenergic, non-cholinergic nerves in the bovine isolated retractor penis muscle. 2 This inhibitory extract did not alter the heart rate or blood pressure of the anaesthetized rat when administered either by intravenous or intra-arterial injection, nor did it have any obvious effect on isolated cardiac muscle. 4 The extract produced relaxation of spiral strips of various arteries isolated from ox, cat, rabbit or rat, in which tone was induced by noradrenaline, K+ of Ba2+. 5 The extract also produced dilatation of the resistance vessels of the rat isolated mesenteric circulation and the rat hindquarters perfused with Krebs solution; tone was induced in these vessels by adrenaline or noradrenaline. 6 Lack of vasodilator activity of the extract in the whole animal appeared to be due to rapid inactivation in the blood, probably by binding to the erythrocytes.

Anesthesia↗
PubMed2002

Spontaneous resolution of a superior mesenteric vein thrombosis after laparoscopic nissen fundoplication.

A previously fit 37-year-old man developed superior mesenteric venous thrombosis after undergoing a laparoscopic Nissen fundoplication. Despite receiving thrombo-embolic prophylaxis on postoperative day 16, he presented with a gradual onset of vague, but severe, umbilical and epigastric pains. Laboratory tests, abdominal ultrasound scan and gastroscopy were all unremarkable. Contrast enhanced abdominal spiral computerised tomography (CT) revealed a partial occlusion of the superior mesenteric and portal vein due to a thrombus; abnormal flow was confirmed on colour Doppler ultrasound. A predisposing hyper-coagulable condition was excluded. The patient responded rapidly to expectant management and a repeat spiral CT scan, 3 weeks after the initial presentation, demonstrated complete re-canalisation of the vessel. Although rare, superior mesenteric venous thrombosis is probably underdiagnosed due to the vague nature of the symptoms, the lack of clinical signs, a low index of suspicion on the part of the clinician, and then subsequent failure to request the optimal investigation--namely contrast enhanced abdominal spiral CT scan. We discuss the possible mechanisms by which laparoscopic surgery may increase the risks of developing superior mesenteric venous thrombosis, the pitfalls in diagnosis and treatment options.

Abdominal Pain↗
PubMed1991

Splanchnic and cerebral vasodilatory effects of calcitonin gene-related peptide I in humans.

The ability of synthetic human calcitonin gene-related peptide (CGRP I) to act as an arterial vasodilator was tested in healthy men by measuring arterial blood flow parameters in carotid, superior mesenteric, celiac, and femoral vessels. Calculated volume flow was significantly increased (140 +/- 21% of basal) in the SMA with a 2-ng/kg/min infusion of CGRP. Carotid artery volume flow increased dose dependently (96 +/- 6%, 122 +/- 15%, 135 +/- 15% of basal, respectively, with 2, 4, or 8 ng/kg/min). With steady-state infusion, carotid and superior mesenteric arterial flow parameters remained significantly elevated for 30 minutes after cessation of peptide administration. Blood pressure was unchanged. Pulse increased dose dependently. Arterial diameters were unchanged, implying activity at the arteriolar level.

Adult↗
PubMed2001

Role of Rho-associated protein kinase in tone and calcium sensitivity of cannulated rat mesenteric small arteries.

The regulation of vascular tone includes modulation of contractile element calcium sensitivity. We tested the involvement of the Rho-associated protein kinase p160ROCK in tone and calcium sensitivity of cannulated rat mesenteric small arteries. These vessels developed basal tone and showed myogenic responses upon pressure steps, resulting from an increase in calcium in combination with a high contractile element calcium sensitivity. Y-27632, believed to be a specific p160ROCK inhibitor, caused concentration-dependent inhibition of basal tone, with near full inhibition at 3 microM. At this concentration, myogenic responses were absent and stepwise pressure elevation resulted in severe vascular distension. Y-27632 did not affect pressure-induced changes in intracellular calcium but rather reduced pressure-induced as well as phenylephrine-induced calcium sensitisation. Thus in the presence of the blocker, for a given calcium concentration, tone was greatly reduced, and the divergence in sensitivity between pressure and phenylephrine as stimuli on the one hand and potassium on the other disappeared. K+ (125 mM) and ionomycin still caused contraction in the presence of the p160ROCK blocker. These data show that in pressurised small arteries the Rho-p160ROCK pathway is active in the absence of vasoconstrictors, keeping the vessels in a state of high calcium sensitivity and basal tone.

Amides↗
PubMed1987

Active, passive and myogenic characteristics of isolated rat intramural coronary resistance arteries.

We have investigated the active, passive and myogenic tension-internal circumference relations of rat intramural coronary and, as controls, mesenteric small arteries (internal diameter ca. 200 micron) using an isometric myograph. The active tensions of the vessels (when fully activated with 30 microM serotonin in K-saline) reached a maximum (2.54 N/m, coronary; 3.39 N/m, mesenteric) at an internal circumference, L0, where the passive tensions (measured in Ca-free solution) were 0.80 N/m (coronary) and 0.74 N/m (mesenteric). Below 0.8 L0 and above 1.2 L0 the active tensions fell linearly, the zero tension intercepts being 0.37 L0 and 1.74 L0 (coronary) and 0.40 L0 and 1.72 L0 (mesenteric). The passive wall tensions of the vessels rose exponentially as a function of internal circumference, the wall tension at 1.5 L0 being 10.0 N/m (coronary) and 8.5 N/m (mesenteric). In normal physiological salt solution, the coronary vessels had a Ca2+ dependent myogenic tone which was also dependent on the internal circumference. Maximum myogenic tone (0.54 N/m) was obtained at 1.18 L0. The mesenteric vessels had no such myogenic tone. Histological examination showed that the media/lumen ratios of both vessel types were the same, and that the smooth muscle content of the media was greater in the coronary (81%) than in the mesenteric (72%) vessels. The smaller active tension of the coronary vessels could not therefore be ascribed to a reduced smooth muscle content, but possibly in part to an observed heterogeneous arrangement of the smooth muscle cells in the coronary vessels.

Animals↗
PubMed2000

Detection of thrombosis in the portal venous system: comparison of contrast-enhanced MR angiography with intraarterial digital subtraction angiography.

PURPOSE: To determine whether intraarterial digital subtraction angiography (DSA) can be replaced by contrast material-enhanced magnetic resonance (MR) angiography in the assessment of patency or thrombosis of the portal venous system in patients with portal hypertension. MATERIALS AND METHODS: Thirty-six patients with portal hypertension underwent contrast-enhanced MR angiography and intraarterial DSA for assessment of the portal venous system. The images were evaluated for vessel patency or thrombosis of the portal, splenic, or superior mesenteric vein. RESULTS: Of the 101 vessels evaluated, 42 were thrombosed. Overall sensitivity, specificity, and accuracy for the detection of thrombosis were 100%, 98%, and 99%, respectively, for MR angiography and 91%, 100%, and 96%, respectively, for DSA; differences between the imaging methods were not statistically significant. Only in four patients with six vessels (6%) were there discordant findings between MR angiography and DSA. CONCLUSION: Noninvasive contrast-enhanced MR angiography has the potential to replace intraarterial DSA as the standard method to assess the whole portal venous system.

Adolescent↗
PubMed1996

Helical CT for the study of abdominal aortic aneurysms in patients undergoing conventional surgical repair.

OBJECTIVES: To evaluate the reliability of helical computed tomography (CT) as sole preoperative diagnostic technique for abdominal aortic aneurysms (AAA) and to compare these results with the surgical findings. MATERIALS: Thirty-three patients undergoing elective surgical repair. METHODS: Helical CT, Doppler exam of lower limbs, digital angiography, in case of peripheral vascular disease, and intraoperative evaluation. RESULTS: Helical CT correctly detected, in all cases, the proximal and distal extent of the AAA. The coeliac axis and its branches, the superior mesenteric artery and renal vessels as well as the inferior vena cava were always clearly depicted, showing anatomical variants or pathological involvement in 14 patients (42.4%). CONCLUSIONS: Helical CT can be used as the sole method for preoperative imaging of AAA. It allows a complete and precise evaluation of size, extent and relationship of the AAA, the surrounding vessels and other abdominal structures.

Aged↗