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At least 613 records · Page 34Linked to original sources
PubMed1985

Serotonergic mechanisms in isolated human peripheral arteries and veins.

Isolated arteries and veins from the hand and mesentery of healthy human subjects were studied in vitro. Serotonin caused contraction with an intrinsic activity approximately equal to that of norepinephrine and epinephrine in mesenteric and hand arteries and veins. Ketanserin inhibited the response to serotonin in a competitive, probably partly irreversible manner in the mesenteric vessels and the hand arteries. In the hand veins, ketanserin counteracted the serotonin-induced contraction in a noncompetitive way.

Adult↗
PubMed2005

Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model.

Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findings--compared with pathologic diagnoses-- predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia.

Acute Disease↗
PubMed1984

Inferior mesenteric arteriovenous fistula associated with portal hypertension and acute ischemic colitis. Successful occlusion by intraarterial embolization with steel coils.

The authors report a case of postoperative arteriovenous fistula between the inferior mesenteric vessels. This fistula was revealed by portal hypertension, with bleeding esophageal varices, ascites, and encephalopathy, and by acute ischemic colitis. Histologic examination of the liver was normal. All of the symptoms disappeared after transcatheter embolization of the fistula with stainless steel coils. This case report favors the reality of the so-called "forward" portal hypertension and suggests that inferior mesenteric arteriovenous fistula might be a factor predisposing to nonocclusive ischemic colitis.

Acute Disease↗
PubMed1985

Activation of the hypothalamo-neurohypophysial system by hypertonic superfusion of the rat mesentery.

Well-defined areas of the mesentery were superfused during 3 s with 300 microliters of hypertonic NaCl solution, while monitoring the electrophysiological response of the hypothalamo-neurohypophysial tract. Response magnitudes were largest for superfusion of the portal, the duodenal and jejunal mesenteric veins, and least for superfusion of the mesenteric vessels of the ileum. The results suggest the existence of peripheral receptors that appear to be strategically located to monitor the intestinal absorption of salt or water.

Animals↗
PubMed1999

[Computerized tomography features of intestinal infarction: 56 surgically treated patients of which 5 with reversible mesenteric ischemia].

PURPOSE: Bowel infarction is a rare and typical condition of the elderly; despite improvements in diagnostic imaging and vascular surgery, bowel infarction remains a major cause of acute abdomen, with mortality rates ranging 70-80%. Diagnosis is often late because clinical signs, laboratory data and radiologic findings are aspecific. We investigated radiographic and particularly CT patterns of intestinal infarction in 56 patients submitted to surgery within 12 hours of admission. We also report the CT findings of 5 of these patients who had reversible mesenteric ischemia. MATERIAL AND METHODS: We retrospectively reviewed 56 cases of bowel infarction. The patients were 29 men and 27 women ranging in age 46-84 years (mean: 63). All the patients were submitted to plain radiography of the abdomen in different projections; emergency CT was carried out with i.v. contrast agent injection. We considered the following CT patterns: dilatation of intestinal loops > 2.5-3 mm, wall thickening > 3-4 mm, intraperitoneal effusion, stuffing of mesenteric vessels with diameter > 3 mm, air-fluid levels. RESULTS: Patients in the 7th decade of life were most frequently affected (38 cases), with an overall mortality rate of 59% (33 deaths). Plain radiography showed distention of bowel loops with air-fluid levels in 91% of cases. CT proved to be an accurate technique with higher sensitivity than radiography in detecting mesenteric edema and hemorrhage (68%), abdominal and pelvic effusion (88%), parietal pneumatosis (9%), wall thickening (29%), intraportal gas (7%), and thrombosis of superior mesenteric artery (3.5%). CT patterns in the 5 patients with reversible intestinal ischemia were wall thickening (80%), peritoneal effusion (80%), meteoric dilatatation (40%), a blurred appearance of mesenteric fat (40%). CONCLUSIONS: Angiography is a valuable imaging and treatment technique permitting the diagnosis of vascular occlusion and the intraarterial infusion of vasodilators, but it can be carried out in emergency in few centers only. This makes conventional radiology, and particularly CT, the only tool providing useful information for early diagnosis and treatment of bowel infarction. CT is more sensitive than radiography and does not exhibit the limitations of angiography--i.e., invasiveness, radiation exposure and complex organization. Therefore CT can presently be considered the method of choice in patients with suspected bowel infarction.

Aged↗
PubMed1980

Extensive gangrene of the bowel after haemorrhagic shock: a case report.

A 20-year-old man presented with an acute abdominal condition within 15 hours after having sustained severe extra-abdominal injuries with associated hypovolaemic shock. At laparotomy virtually the whole bowel was found to be ischaemic and perforation had occurred at the site of maximum ischaemia. No trauma to the bowel, mesenteric vessels or any other abdominal organ was noted, and it was concluded that the ischaemia had resulted from a prolonged splanchic vasospasm in an attempt to compensate for hypovolaemic shock. The condition is well recognized in animals, but has rarely been recorded in humans. Early resuscitation of the shocked patient is mandatory in order to prevent not only renal shutdown but also mesenteric ischaemia. It is possible that some patients who suffer from 'irreversible shock' may develop endotoxaemia owing to the absorption of toxins from partially ischaemic bowel which does not proceed to frank gangrene.

Adult↗
PubMedDate not supplied

Reduction in thrombus formation by PG-1 F(ab')2, an anti-guinea pig platelet glycoprotein Ib monoclonal antibody.

We have recently demonstrated that intraperitoneal injection into guinea pigs of F(ab')2 fragments of PG-1, a murine monoclonal antibody recognizing the guinea pig homologue of human platelet glycoprotein Ib, produces virtually complete functional block of the platelet von Willebrand factor receptor without inducing a hemorrhagic state. To assess the ability of this antibody to protect against thrombosis resulting from laser-induced injury to mesenteric small arteries, we injected guinea pigs with either PG-1 F(ab')2 (2.3 mg/kg) or with buffer alone 24 hours before study. For each animal, four mesenteric vessels were studied consecutively for 15 minutes each. The number of thrombi, time to first thrombus, and time to embolization of first thrombi were recorded. In the control animals most individual vessels had three to four thrombi, whereas in the antibody-treated animals, vessels most frequently had only a single thrombus or even none at all. The mean number of thrombi per vessel in the antibody-treated animals (1.125) was significantly lower than the mean in the control animals (3.40), with p less than 0.001. However, there was no significant difference between groups with respect to time to first thrombus after laser injury. Detachment of thrombi in the control animals occurred in an easily recordable, discrete fashion, with 75% of first thrombi embolizing in less than 5 minutes. In the antibody-treated animals, gradual dissolution rather than discrete detachment was typically observed. In 31% of the vessels studied in these animals, no embolus occurred; for the remaining vessels only 9% of thrombi were observed to embolize within 5 minutes of their formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

Simultaneous allotransplantation of kidney and spleen in dogs with or without previous splenectomy.

29 simultaneous kidney and spleen transplantations have been performed on dogs. Time of rejection, similar for both organs, occurs in a delay very close to the control series. No statistically difference of the day of rejection was observed in relation with the implantation of the spleen either on the iliac or on the mesenteric vessels. Splenectomy few weeks prior to transplantation had no effect on the day and the histological type of rejection of both transplanted organs.

Animals↗
PubMed1990

Vascular lesions in intestinal ischemia induced by cocaine-alcohol abuse: report of a fatal case due to overdose.

Intestinal ischemia induced by cocaine abuse is a rare condition. To this date, only three cases have been described. The diagnosis of bowel ischemia should be suspected whenever a cocaine addict has severe abdominal pain. A pathological examination of the resected bowel segment was performed in one case, and the diagnosis was confirmed microscopically. However, the existence of pathologic alterations of the intestinal vessels was not confirmed. Why the intestinal injury is segmental and whether it is related to the dose ingested, the administration route, or the combination of cocaine with alcohol, caffeine, or marijuana remain unclear. The authors report one fatal case associated with cocaine-alcohol overdose. The postmortem examination demonstrated the existence of segmental intestinal ischemia. Microscopic study failed to demonstrate thrombosis in the mesenteric vessels; however, we found an unusual lesion affecting the arterioles located in the intestinal submucosa of the hemorrhagic areas.

Adult↗
PubMed2002

Effect of exercise on blood pressure in rats with chronic NOS inhibition.

Regular training lowers blood pressure in hypertensive humans and other animals. We investigated the response to 4 weeks of treadmill exercise training in hypertensive male Wistar rats receiving the nitric oxide synthase inhibitor N(omega)-nitro- L-arginine methyl ester ( L-NAME). The rats were on either a short- (4 weeks) or long-term (10 weeks) L-NAME treatment protocol and were subjected to running exercise that started concomitantly in the short-term group and in the 6th week in the long-term group. Four weeks of exercise training induced a fall in mean arterial pressure in both the short- [mean (SEM) 137.6 (4.0) mmHg] and long-term hypertensive groups [161.4 (2.3) mmHg] compared to their sedentary hypertensive controls [160.4 (3.3) mmHg and 176.8 (8.9) mmHg, respectively]. Exercise also increased muscle nitric oxide synthase activity in both of the trained hypertensive groups. Muscle nitrite levels were higher in the exercising short-term hypertensive group compared to both the sedentary control and the sedentary hypertensive groups, and were not different between the sedentary and exercising long-term hypertensive groups. Increased wall thickness of the aortic and mesenteric vessels was observed in the hypertensive groups, but was prevented in the exercising long-term hypertensive group. In rat, exercise reduces the elevated blood pressure in L-NAME-induced hypertension via increasing nitric oxide synthase activity. Changes in vessel structure with exercise training may also be involved in the blood-pressure-lowering effects.

Adaptation, Physiological↗
PubMed2003

CT in acute mesenteric ischaemia.

Enhanced computed tomography (CT) is frequently performed for possible bowel ischaemia. It has the distinct advantage of possible detection of the causes of ischaemia. Radiologists therefore need to be familiar with the spectrum of diagnostic CT signs. We present the CT imaging findings in surgically proven cases of small bowel ischaemia. In addition to signs pertaining to the underlying aetiological pathology, bowel dilatation, bowel wall thickening, mural gas, occlusion of mesenteric vessels, ascites and infarct of other abdominal organs were observed.

Abdomen, Acute↗
PubMed1989

Arteriomesenteric duodenal occlusion associated with strongyloidiasis.

Arteriomesenteric occlusion of the distal duodenum may occur in clinical conditions which result in narrowing of the angle between the aorta and superior mesenteric artery. Two patients with arteriomesenteric duodenal occlusion associated with Strongyloides stercoralis infection are described. In one patient the mechanism of occlusion appeared to be significant weight loss and associated visceroptosis, while in the other patient increased diameter of superior mesenteric vessels was the major factor. Strongyloidiasis, a curable parasitic infection, should be considered in patients presenting with arteriomesenteric occlusion of the distal duodenum.

Adolescent↗
PubMed1993

Intestinal ischemia resulting from Buerger's disease: report of a case.

A 42-year-old man who had undergone below-the-knee amputations for Buerger's disease 9 and 14 years earlier required emergency surgery for intestinal ischemia caused by arterial occlusive lesions in the mesentery. The cecum and proximal part of the ascending colon were resected, and marked hyperemic thickening of the wall and severe fibrous adhesions were found. Postoperative angiography revealed occlusions in the superior mesenteric and right external iliac arteries. The resected specimen showed mucosal necrosis of the cecum and circular ulcers at Bauhin's valve and at the ascending colon. Microscopically, small mesenteric vessels were occluded by organized and recanalized thrombi with preserved vascular architecture. The patient has remained free of any further intestinal symptoms for 1 year following his discharge from hospital.

Adult↗
PubMed1993

Design of a microwave system for endoscopy: an experimental study of energy, tissue contact, and hemostatic efficacy.

BACKGROUND: A microwave generator and delivery system for endoscopic use was built. Using a 650-W, 2450-MHz magnetron, 0-160 W were generated from the tip of a 180-cm flexible coaxial cable (2.1 mm diameter). METHODS: Three methods of achieving hemostasis with microwaves were identified studying standard bleeding canine ulcers: (1) interstitial method: inserting the coaxial tip into the tissue and heating slowly until bleeding stopped; (2) contact method: tip held in contact, light pressure applied; (3) noncontact method: microwave-induced sparking (dielectric breakdown) with tip held 1 mm from tissue. RESULTS: Studies of optimal energy levels for hemostasis showed that high power (70 W) noncontact methods required significantly less energy to stop bleeding than contact or interstitial methods. The noncontact method was more effective than the contact method, stopping 20 of 20 bleeding ulcers vs. 10 of 20 (P < 0.001) and was more rapidly effective causing less tissue damage (P < 0.05) than the interstitial method. CONCLUSIONS: In a randomized comparison using a non-contact method, microwave coagulation was superior (P < 0.001) to a polidocanol 1% + adrenaline 1:10,000 injection and control treatment stopping 40 of 40 vs. 0 of 20 and 0 of 20 standard bleeding ulcers. Microwaves stopped bleeding from 10 of 10 severed mesenteric vessels, whereas injection was ineffective (0 of 10, P < 0.001). Microwaves look promising for hemostasis at flexible endoscopy.

Animals↗
PubMed1993

Gastrointestinal vascular and ischemic syndromes.

Among the vascular disorders of the small intestine, two major categories are mesenteric ischemia and occult gastrointestinal bleeding secondary to a mucosal or muscular lesion. Mesenteric ischemia remains a clinical entity with a high mortality. Recent advances in the understanding of the pathogenesis of mesenteric ischemia have focused on the role of the neutrophil in modulating reperfusion injury. The advent of duplex scanning has provided a noninvasive method to detect hemodynamically significant stenoses in the mesenteric vessels. Effective small bowel endoscopy remains a critical requirement for endoluminal intestinal enteroscopy, and its application has proved of increasing advantage in the localization of small intestinal lesions that may be the source of occult gastrointestinal bleeding.

Gastrointestinal Hemorrhage↗
PubMed1989

Glomerular and vascular atrial natriuretic factor receptors in adrenalectomized rats.

The renal and vascular responses to atrial natriuretic factor (ANF) and glomerular and vascular ANF receptors were studied in adrenalectomized (ADR) rats with or without deoxycorticosterone (DOC) or dexamethasone (Dexa) replacement therapy. As expected, adrenalectomy elicited hypotension, hemoconcentration, and increased plasma renin activity, but no changes in plasma levels of either ANF-(1-98) or ANF-(99-126) were detected. Dexa treatment decreased both ANF-(1-98) and ANF-(99-126), whereas DOC treatment increased only ANF-(1-98). The acute renal response to ANF and furosemide was reduced in ADR rats and partially restored either by steroid replacement or by raising blood pressure. The blunted natriuretic response to ANF in ADR rats was associated with an increased density of glomerular receptors. Norepinephrine-precontracted vascular strips from ADR rats were more sensitive to ANF (ED50: 1.7 x 10(-8) M) than those from sham-operated animals (ED50: 1.5 x 10(-7) M). However, vascular ANF receptor density in mesenteric vessels from ADR animals was decreased. Dexa treatment restored vascular response to that observed in sham-operated animals without a concomitant change in vascular receptor density. Because the presence of guanylate cyclase-coupled and noncoupled ANF receptor subtypes have been described in different tissues, we conclude that the apparent lack of correlation between the biological response to ANF and total binding of ANF to glomeruli or mesenteric artery membranes in ADR rats may be in part caused by a differential regulation of both receptor subtype populations.

Adrenalectomy↗
PubMed2001

Different role of endothelium/nitric oxide in 17beta-estradiol- and progesterone-induced relaxation in rat arteries.

The present study was aimed to examine the different role of endothelium/nitric oxide in relaxation induced by two female sex hormones, 17beta-estradiol and progesterone in rat isolated aortas and mesenteric arteries. The isometric force of each ring was measured with Grass force-displacement transducers in the organ bathes. 17beta-Estradiol induced both endothelium-dependent and -independent relaxation in the rat aortas but only the endothelium-independent relaxation in the rat mesenteric arteries. In contrast. progesterone induced both endothelium-dependent and -independent relaxation in the rat mesenteric arteries but only endothelium-independent relaxation in rat aortas. N(G)-Nitro-L-arginine methyl ester and methylene blue attenuated the relaxant response to 17beta-estradiol in the aortic rings or to progesterone in the mesenteric arteries. Pretreatment with L-arginine antagonized the effect of N(G)-nitro-L-arginine methyl ester on sex hormone-induced relaxation. The endothelium contribution to relaxation seems to only relate to lower concentrations of 17beta-estradiol and progesterone. In summary, the present results clearly demonstrate a different role of the functional endothelium in the relaxant response to 17beta-estradiol or progesterone in the conduit vessel (aorta) and the resistance vessels (mesenteric artery). Nitric oxide contributes largely to the endothelium-dependent relaxation induced by 17beta-estradiol in the isolated aortas or by progesterone in the mesenteric arteries.

Animals↗