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PubMed1989

Catecholamines relax portal and mesenteric veins from normal and portal hypertensive rats.

The relaxation by catecholamines of superior mesenteric veins and portal veins, precontracted by 65 mM KCl, was studied after a 2-h exposure to phenoxybenzamine. The veins were obtained from portal-hypertensive and sham-operated rats. The beta 2-selective antagonist ICI 118551 attenuated the relaxation caused by epinephrine and isoproterenol but did not change the relaxation caused by norepinephrine in superior mesenteric veins. The beta 1-specific antagonist CGP 20712A reduced the relaxation caused by norepinephrine but only marginally attenuated those caused by epinephrine and isoproterenol in superior mesenteric veins. The combination of ICI 118551 and CGP 20712A abolished the relaxation caused by the catecholamines in superior mesenteric veins. The relaxation caused by norepinephrine, epinephrine, and isoproterenol was markedly reduced by ICI 118551 in portal veins. The pattern of antagonism was similar in veins from portal-hypertensive and sham-operated rats. The results suggest that both beta 1- and beta 2-adrenoceptors mediate relaxation induced by catecholamines in superior mesenteric veins. Relaxation of portal veins appears to be mediated mostly by beta 2-adrenoceptors.

Adrenergic beta-Antagonists↗
PubMed1987

Mechanical, morphological and pharmacological properties of oesophageal varices and small mesenteric veins in portal hypertensive rabbits.

The properties of isolated small oesophageal and mesenteric veins were investigated in a rabbit model subjected to a 4-week period of portal vein stenosis. The animals developed oesophageal varices and these together with the small mesenteric veins were mounted on a myograph. Compared with sham-operated controls portal hypertension resulted in an increased normalized inner radius and media thickness of the oesophageal veins resulting in a non-significant increase in the media to lumen ratio, while the inner radius decreased as media thickness increased in mesenteric veins resulting in a significant (P less than 0.01) increase in the media to lumen ratio. When activated, the active wall tension of both the oesophageal and mesenteric veins was increased following portal hypertension, but the active media stress was unchanged. The EC50 for noradrenaline and angiotensin II did not change in portal hypertensive vessels compared with controls and was equal in oesophageal and mesenteric vessels. The ability of isoprenaline and serotonin to relax pre-contracted vessels of both types was reduced by the portal hypertension. The results of these studies suggest that the development of oesophageal varices is not only due to increased portal venous pressure.

Angiotensin II↗
PubMedDate not supplied

Mesenteric vein thrombosis. Four cases and review of the literature.

Mesenteric vein thrombosis, an uncommon but important clinical entity, can cause ischemia or infarction of the small intestine. Mesenteric vein thrombosis was first described nearly a century ago, but diagnosis remains difficult because it can affect young individuals without any known predisposing disorder and because patients often present with nonspecific abdominal symptoms. We report 4 cases of small intestinal ischemia secondary to superior mesenteric vein thrombosis. Three were due to hypercoagulable states (protein-S deficiency, factor-VII abnormalities) and one was idiopathic. In recent years, the development of modern imaging techniques (particularly ultrasonography, duplex scanning, and computed tomography) have enabled early recognition of this disease. Anticoagulation is therapeutic acutely unless there are signs of peritonitis which necessitate surgical resection of the infarcted bowel.

Adult↗
PubMed1992

Sonographic diagnosis of intestinal malrotation in infants: importance of the relative positions of the superior mesenteric vein and artery.

OBJECTIVE: An abnormal relative position of the superior mesenteric vein and artery can be present in patients with intestinal malrotation. We undertook this retrospective study to see how often we could determine the relative position of these vessels on abdominal sonograms in infants and how often abnormal position of the vessels was associated with malrotation. MATERIALS AND METHODS: We reviewed the radiology files and medical records of 337 infants with vomiting who were referred for sonography because of possible pyloric stenosis. We used sonograms and written reports to determine the position of the superior mesenteric vessels. The position was considered normal when the superior mesenteric vein was to the right of the superior mesenteric artery on transverse sonograms. The position was considered abnormal when the vein was directly ventral to the artery or when the vein was to the left of the artery. Sonographic findings were compared with results of upper gastrointestinal series when possible and with clinical outcome. RESULTS: The relative positions of the superior mesenteric vein and artery were evident in 249 (74%) of the 337 patients. Abnormal orientation of the mesenteric vessels was detected in nine patients. In five patients, the superior mesenteric vein was located to the left of the artery, and all five had intestinal malrotation. In four patients, the superior mesenteric vein was directly ventral to the artery, and one of these had malrotation. CONCLUSION: Sonographic assessment of the relative positions of the mesenteric artery and vein is an important adjunct in the examination of infants with suspected pyloric stenosis. Patients in whom sonograms show an abnormal position of the vessels should have further examination to detect malrotation.

Congenital Abnormalities↗
PubMed1990

Mesenteric vein thrombosis in protein S congenital deficiency.

Mesenteric vein thrombosis is considered an uncommon clinical presentation of protein S congenital deficiency. In the two patients with mesenteric vein thrombosis here reported an isolated deficiency of protein S was diagnosed; family investigation recognized protein S deficiency also in five relatives of one of them.

Adult↗
PubMed1991

Idiopathic myointimal hyperplasia of mesenteric veins.

Nonthrombotic occlusion or stenosis of the mesenteric veins is a rare cause of intestinal ischemia that usually occurs in association with systemic vasculitis. The current report includes four male patients with segmental ischemic colitis caused by idiopathic myointimal hyperplasia in the small mesenteric veins and their intramural branches; neither vasculitis nor arterial involvement were present. Three of the four patients were less than or equal to 38 years of age; the fourth was 67. All four patients were previously healthy and had no history of drug use of any kind. Clinical findings included abdominal pain, diarrhea, bloody stools, and colonic strictures discovered by barium enema. The intima of the mesenteric and intestinal mural veins was focally thickened by a marked increase in cells and matrix between the endothelium and internal elastic lamina, whereas the vessel walls external to the thickened intima appeared normal. Histochemistry and immunoreactivity with antibodies to muscle-specific actins (HHF-35) disclosed that the intimal thickening was caused by proliferation of smooth muscle cells in a proteoglycan matrix. All patients recovered completely after segmental resection of the ischemic portion of the colon and had no recurrence of intestinal symptoms on follow-up of up to 7 years. These unusual venous lesions do not appear to have been previously described; their etiology and pathogenesis remain unknown.

Adult↗
PubMed2006

Focal myointimal hyperplasia of mesenteric veins is associated with previous trauma in surgical specimens.

Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare and poorly understood disease that occurs in the rectosigmoid colon of predominantly young, previously healthy, male patients. This disease is often confused with chronic idiopathic inflammatory bowel disease clinically, and pathologists may miss the diagnosis unless elastin stains are performed because diseased veins may readily be mistaken for arteries. The etiology of IMHMV is unclear, but a traumatic pathomechanism resulting in arterialization of the veins has been proposed. Review of bowel resection specimens (n=68) for non-neoplastic disease within a 1-year period in patients younger than 50 years of age revealed 10 cases with focal mesenteric vein myointimal hyperplasia. Significantly more cases with focal myointimal hyperplasia of mesenteric veins (MHMV) were associated with pre-resection trauma to the involved bowel segment (5/11 vs. 5/57; p=0.0016). A significant association of MHMV with pre-resection trauma supports the hypothesis that idiopathic myointimal hyperplasia of the mesenteric veins may be the result of trauma through torsion/stretching of the sigmoid colon and, subsequently, increased mesenteric venous pressure through arterialization.

Adult↗
PubMed1992

Non-traumatic rupture of the superior mesenteric vein with hemoretroperitoneum.

A case of rupture of the superior mesenteric vein with hemoretroperitoneum is described. The autopsy revealed the presence of an acute pancreatitis and thrombosis of the superior mesenteric artery. From the histological findings it appeared that the acute pancreatitis had damaged the venous wall from the outside and that the portal system overload, caused by the superior mesenteric artery thrombosis and the anomalous termination of the inferior mesenteric vein, acted from the inside of the vein causing its rupture. To our knowledge this is the first report of a rupture of the superior mesenteric vein caused by acute pancreatitis and resulting in hemoretroperitoneum.

Acute Disease↗
PubMed1999

Mesenteric vein thrombosis secondary to protein S deficiency.

Mesenteric vein thrombosis is an uncommon condition. Diagnosis is often difficult because of the nonspecific clinical presentation and findings on routine laboratory and radiological evaluation. Endoscopy is usually unrevealing. An underlying hypercoagulable state is often present, but protein S deficiency has rarely been implicated. We describe a case in which chronic inferior mesenteric vein thrombosis, with remarkable endoscopic findings, occurred as the initial presentation of type I protein S deficiency.

Angiography↗
PubMed1995

Small intestinal stricture complicating superior mesenteric vein thrombosis. A study of three cases.

Mesenteric vein thrombosis associated with intestinal stricture, as a consequence of intestinal ischaemia, has only been mentioned twice in published works. The clinical, biological, and morphological aspects as well as the treatment of this morbid association were studied in three patients. In all, a two stage clinical course (initial acute abdominal pain and fever, followed by chronic intestinal obstruction), corresponding to the sequence thrombosis/stricture, was found. x Ray studies showed a regularly contoured intestinal stricture. Surgical resection was required in all three cases for stricture, associated in one case with mesenteric infarction. Anticoagulation treatment was used to preclude recurrence. Increased clinical awareness could lead to the diagnosis of intestinal stricture secondary to mesenteric vein thrombosis more often and at an earlier stage. Treatment consists of evaluation of predisposing features, intestinal resection when necessary, and anticoagulation therapy, as indicated.

Adult↗
PubMed1980

Mesenteric vein thrombosis. The importance of a second-look operation.

Mesenteric vein thrombosis is an abdominal emergency that is rarely diagnosed early. Review of the literature has shown that most cases have been treated by intestinal resection, a few by thrombectomy with or without resection. Three cases of mesenteric vein thrombosis were treated by resection, heparinization, and a second-look operation after 24 hours. When necessary, resection was carried out at the second surgical procedure followed by a third-look operation after 24 hours. After the last inspecting operation without further resection, full heparinization was continued and anticoagulation was ultimately maintained with warafin sodium (Coumadin) for at least three months. The authors believe that optimal treatment for mesenteric vein thrombosis should include anticoagulation with heparin sodium and a mandatory second-look operation.

Adult↗
PubMed1991

Actions of dipyridamole on endogenous and exogenous noradrenaline in the dog mesenteric vein.

1. In the isolated mesenteric vein of the dog, dipyridamole inhibited both the excitatory junction potential (e.j.p.) and the slow depolarization evoked by perivascular nerve stimulation, to 60-70% of control, with no change in the postjunctional membrane potential. These inhibitory actions of dipyridamole were not modified by 8-phenyltheophylline or phentolamine, suggesting that the inhibition did not involve either the actions of endogenous adenosine or the prejunctional alpha-autoregulation mechanism. 2. Dipyridamole did not produce any detectable effects on either the facilitation process of the e.j.ps or the postjunctional membrane depolarization produced by exogenously applied noradrenaline (NA). 3. Dipyridamole reduced the outflow of both the NA and the 3,4-dihydroxyphenylglycol (DOPEG) evoked by perivascular nerve stimulation to below 10% of control, the effect being much greater than that of exogenously applied adenosine (to about 90% of the control). 4. Exogenously-added NA was degraded by incubation with a segment of the vein. Dipyridamole itself produced degradation of NA and accelerated the NA-induced degradation. By contrast, pyrogallol, but not pargyline or imipramine, prevented the NA-induced degradation. 5. It is suggested that dipyridamole degrades NA directly, and also indirectly through activation of catechol-O-methyl transferase, with no alteration of the activity of monoamine oxidase or of the uptake mechanisms of NA into nerve terminals.

Adenosine↗
PubMed1998

[The effect of activity of smooth muscles on the relationship of circumferential stress-strain of superior mesenteric veins in rabbits].

The superior mesenteric veins (SMV) of 14 rabbits were divided into two groups for experiment of inflation pressure, namely the normal group and the inactivated smooth muscles group. The results showed that the relationship of circumferential stress-strain of SMV could be expressed with the exponential equation. Constant X2 is effected by the active condition of smooth muscles. The difference of the material constant X2 between the two groups was statistically significant (P < 0.05), but the difference of the material constant X1 between the two groups was not statistically significant (P > 0.05). These suggest that X2 is the parameter concerning the activity of smooth muscles.

Animals↗
PubMed2006

Systematic review of outcome of synchronous portal-superior mesenteric vein resection during pancreatectomy for cancer.

BACKGROUND: Tumour clearance during pancreatectomy may be facilitated by resection of the portal-superior mesenteric vein, but this is associated with increased perioperative risk. There is no consensus about which patients benefit from portal-superior mesenteric vein resection. METHODS: A systematic appraisal was carried out of the literature on portal-superior mesenteric vein resection during pancreatectomy to identify recurrent themes to guide management. A computerized search of the Medline and Embase databases found 52 non-duplicated studies providing relevant data in 1646 patients. Pooled data were examined for information on outcome categories relating to operation, complications, histopathology and overall outcome. RESULTS: The median (range) number of patients with portal-superior mesenteric vein resection per cohort was 23 (4-172). Median operating time was 513 (168-1740) min and blood loss 1750 (300-26000) ml. Postoperative morbidity ranged from 9 to 78 per cent with a median per cohort of 42 per cent. There were 73 perioperative deaths (5.9 per cent of 1235 for whom mortality data were provided). Median survival was 13 months, and 1-, 3- and 5-year survival rates were 50, 16 and 7 per cent respectively. Specimen histopathology confirmed positive nodes in 67.4 per cent. CONCLUSIONS: This is the largest collective report to date on portal-superior mesenteric vein resection in pancreatectomy. The high rate of nodal metastases and low 5-year survival rates suggest that by the time of tumour involvement of the portal vein cure is unlikely, even with radical resection.

Adult↗
PubMed1990

[Two cases of superior mesenteric vein thrombosis; the utility of CT scan].

Two cases of superior mesenteric vein thrombosis were examined with computed tomography. Prior to the operation the CT appearances of the disease were, as follows: focal thickening of the bowel wall, gas and fluid collection in the dilated bowel, mesenteric leaf, a little ascites and dilated superior mesenteric vein with central filling defect. We conclude that CT scan is very useful for an early diagnosis of the superior mesenteric vein thrombosis.

Aged↗
PubMed1995

Plasma insulin and glucagon responses to propionate infusion into femoral and mesenteric veins in sheep.

Propionate (1, 2, 4, 8, 16, 32, and 64 mumol.kg BW-1.min-1 for 30 min) was infused into the femoral and mesenteric veins of adult sheep to investigate the physiological significance of propionate in regulating plasma insulin and glucagon concentrations. The increments in arterial blood propionate concentrations during propionate infusion increased (P < .001) with increasing infusion rates for both infusion sites, and they were smaller (P < .001) for the mesenteric vein infusion than for the femoral vein infusion. Plasma insulin concentrations during propionate infusion increased (P < .10) from preinfusion values with infusion rates of > or = 8 mumol.kg BW-1.min-1 for both infusion sites. The response areas of plasma insulin concentration above basal tended to be smaller (P < .112) for the mesenteric vein infusion than for the femoral vein infusion. Plasma glucagon concentrations during propionate infusion increased (P < .05) from preinfusion values with infusion rates of > or = 8 and 64 mumol.kg BW-1.min-1 for the femoral and mesenteric vein infusions, respectively. The response areas of plasma glucagon concentration above basal were smaller (P < .011) for the mesenteric vein infusion than for the femoral vein infusion. We conclude that in sheep propionate absorbed from the alimentary tract has a physiological role in regulating circulating concentrations of insulin and glucagon.

Animals↗