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Results for “MESENTERIC VESSELS”

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At least 577 records · Page 32Linked to original sources

PubMed1997

Increased expression of parathyroid hormone-related peptide gene in blood vessels of spontaneously hypertensive rats.

We have shown recently that mechanical stretch of cultured rat aortic smooth muscle cells induces a marked increase in gene expression of the vasorelaxant parathyroid hormone-related peptide. In the present study, we investigated whether mechanical force affected the in vivo parathyroid hormone-related peptide gene expression in blood vessels. Northern blot analysis revealed that stretch of isolated rat aortic strips increased the expression level of parathyroid hormone-related peptide mRNA. The parathyroid hormone-related peptide transcript level in aorta and mesenteric vessels from 18-week-old spontaneously hypertensive rats (SHR) was 2.5- and 2.2-fold higher, respectively, compared with age-matched Wistar-Kyoto (WKY) controls, whereas the parathyroid hormone-related peptide mRNA level in aorta from normotensive 4-week-old SHR was similar to that of age-matched WKY controls. The aortic parathyroid hormone-related peptide content was higher in 18-week-old SHR than in age-matched WKY controls. Moreover, treatment of mature SHR with an angiotensin II type 1 receptor antagonist or hydralazine caused a concomitant decrease in the parathyroid hormone-related peptide transcript level in aorta with lowering of blood pressure. These results suggest that the in vivo parathyroid hormone-related peptide gene expression in blood vessels is under the control of mechanical force, pointing to a role of parathyroid hormone-related peptide in the regulation of vascular tone.

Animals↗

PubMed1985

Vascular and adrenal receptors for atrial natriuretic factor in the rat.

Previous studies have shown that atrial natriuretic factor, a powerful vasorelaxant of precontracted vessels, inhibits the secretion of aldosterone stimulated by angiotensin II, adrenocorticotropic hormone, and potassium. We now report the presence of specific binding sites for atrial natriuretic factor in rat blood vessels (mesenteric and renal arteries) and adrenal capsules. Radioiodinated synthetic atrial natriuretic factor bound to a single class of high-affinity (KD = 0.1 nM) low-capacity receptors in a particulate fraction from blood vessels and adrenals. Unrelated peptides did not displace atrial natriuretic factor. Fragments of atrial natriuretic factor displaced the labeled ligand with decreasing potency after cleavage at the N-terminal. The cleavage of the C-terminal tyrosine did not decrease the potency of atrial natriuretic factor, but further cleavage at the C-terminal dramatically reduced the affinity of the resulting peptides. The potency of the atrial natriuretic factor fragments in the radioligand assay was in proportion to their potency to inhibit aldosterone secretion by isolated rat glomerulosa cells. Our results suggest that these binding sites mediate the biological actions of atrial natriuretic factor in blood vessels and the adrenal, and that both receptors have similar specificities.

Adrenal Glands↗

PubMed1998

Thromboangiitis obliterans (Buerger's disease) with intestinal involvement--a case report.

Thromboangiitis obliterans (TAO) or Buerger's disease is a nonatherosclerotic vascular disease of unknown etiology that occurs almost exclusively in young male tobacco users. The involvement of the medium-sized and small arteries and veins leads to ischemic complaints and trophic changes in the limbs. The authors report a case of Buerger's disease in a 29-year-old man, a heavy smoker, affecting the lower limbs and mesenteric vessels.

Adult↗

PubMed1992

[A scanning electron microscopic study on experimental ischemic lesions in dogs].

Occlusion of minute vessels in the bowel wall is thought to be a cause of ischemic lesions. This study was performed to clarify the pathohistology and the morphology of these various lesions. Microbarium suspension was injected into the mesenteric vessels of twenty four dogs and the ischemic lesions were produced experimentally. The degree of the bowel damage was parallel to the amount of injected microbarium suspension. The resected specimen of the various stages of the disease was studied histologically and morphologically by a scanning electron microscopy. With the small amount of barium suspension the lesions were confined to the mucosal layers. The epithelial cells regenerated regularly and the villi normalized rather quickly, and these lesions healed within one to two weeks (transient form). With the large amount of barium suspension the lesions involved both submucosal and muscular layers. The epithelial cells regenerated irregularly and the villi rearranged to abnormal forms. These lesions healed in two to four weeks leaving the stenosis due to scar formation (stricturing form). This study suggests that scanning electron microscopic investigation can be used to assess the details of morphological changes of ischemic mucosa, special reference to the degeneration and regeneration process of epithelium of the villi.

Animals↗

PubMed1984

[Acute disorders of the mesenteric circulation among heart defect patients].

The author analyzes the clinical picture, diagnostic methods, and results of the treatment of mesenteric artery thromboembolism in 30 patients with rheumatic heart disease. The early symptoms that permit the physician to suspect mesenteric thromboembolism include sudden convulsive pains in the abdomen, vomiting, diarrhea, leukocytosis, and the discrepancy between the clinical picture of the complication and scarce objective data from examining the abdominal cavity. When the diagnosis of the acute occlusion of the mesenteric vessels has been made, urgent surgical intervention is indicated which is to include the resection of the non-viable portion of the intestine and the surgical correction of the blood flow in the superior mesenteric artery.

Acute Disease↗

PubMed2001

Laparoscopic infrared imaging.

BACKGROUND: As an adjunct to direct visual imaging, an infrared endoscope was developed to assist in the identification of various anatomic structures and to assess tissue viability during laparoscopic procedures. A camera sensitive to emitted energy in the mid-infrared range (3 to 5 microm) was incorporated into a two-channel visible-light laparoscope. METHODS AND MATERIALS: Laparoscopic procedures were performed in a porcine model, inexperienced laparoscopists being asked to localize and differentiate structures before dissection using the visible-light system and then the infrared system. To determine clinical utility, nine laparoscopic urologic procedures were performed with the assistance of the infrared system. RESULTS: In the clinical evaluation, infrared imaging proved to be useful in differentiating between blood vessels and other anatomic structures. In contrast to the experience with the conventional endoscope, vessel identification, assessment of organ perfusion, and transperitoneal localization of the ureter was successful in all instances using the infrared system. In the porcine model, this system also permitted assessment of bowel perfusion during laparoscopic occlusion of mesenteric vessels and distinguished between the cystic duct and artery. CONCLUSION: Infrared imaging is a potentially powerful adjunct to laparoscopic surgery. It may improve the differentiation and localization of anatomic structures and allow assessment of physiologic features, such as perfusion, not previously attainable with laparoscopic techniques.

Animals↗

PubMed1977

[Histamine concentration and diamine oxidase activity in the small intestine in superior mesenteric artery occlusion].

During intestinal ischemia in rabbits histamine concentration and diamine oxidase activity were altered in the intestinal wall and in the perfusate of mesenteric vessels. The results were interpreted as a histamine release and an increased catabolism of diamine oxidase. Thus, the combination of release of vasoactive histamine and partial elimination of a protective enzyme may contribute to the fatal outcome after mesenteric ischemia.

Amine Oxidase (Copper-Containing)↗

PubMed1996

Acute intestinal ischemia due to occlusion of the superior mesenteric artery: detection with Doppler sonography.

The aim of our study was to assess the feasibility of using Doppler sonography for the detection of acute intestinal ischemia due to occlusion of the superior mesenteric artery. Between September 1993 and March 1995, abdominal sonography with Doppler imaging of the mesenteric vessels was performed in 770 patients with emergency admissions for acute abdominal pain. In six cases, the diagnosis, based on surgery or arteriography and computed tomography, was acute intestinal ischemia due to complete or localized occlusion of the superior mesenteric artery. Five cases of occlusion of the superior mesenteric artery were correctly detected by Doppler sonography. These results suggest that Doppler sonography may be a feasible method for detecting acute intestinal ischemia due to proximal superior mesenteric artery occlusion.

Adult↗

PubMed2002

Effects of enalapril on the vascular wall in an experimental model of syndrome X.

Evidence links the insulin resistance syndrome with endothelial dysfunction. Previously, we have described a decreased endothelial nitric oxide synthase (eNOS) activity in both aortic endothelium and cardiac tissue, and an increased proliferation of aortic primary cultured vascular smooth muscle cells (pC-VSMCs), obtained from fructose-fed rats (FFR), an experimental model of syndrome X. Because the participation of the renin-angiotensin system (RAS) in this model is still unclear, the present study examined the effect of chronic administration of an angiotensin converting enzyme (ACE) inhibitor enalapril (E) on pC-VSMCs proliferation and eNOS activity in a conduit artery (aorta) and in resistance vessels (mesenteric vascular bed) from fructose-fed rats. Male Wistar rats were used: Control, FFR, Control + E, and FFR + E (n = 8 in each group). After 8 weeks, tissue samples were obtained and 10% fetal calf serum (FCS) proliferative effect was examined in pC-SMCs of aortic and mesenteric arteries by [(3)H]thymidine incorporation. The eNOS activity was estimated in endothelial lining from both origins by conversion of [(3)H]arginine into [(3)H]citrulline. The FFR aortic and mesenteric pC-VSMCs showed a significantly increased 10% FCS-induced [(3)H]thymidine incorporation compared to controls. The FFR aortic and mesenteric endothelium eNOS activity was significantly decreased. Chronic treatment with E abolished the increased proliferation and restored eNOS activity. These data confirm that changes in VSMCs proliferation and endothelial dysfunction at different levels of the vascular system are involved in syndrome X, and that the inhibition of angiotensin II production can revert those changes, suggesting an important role for RAS and possibly kinins, in the physiopathologic mechanism of this model of syndrome X.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1986

Ultrasonically induced intravascular streaming and thrombus formation adjacent to a micropipette.

Ultrasonically induced microstreaming around bubbles of gas have been shown to cause damage to biological materials in vitro at clinical exposure levels. The potential for ultrasonically induced cavitation and microstreaming in mammalian systems is of interest with respect to the safe application of clinical ultrasound. Ultrasonically induced intravascular microstreaming and formation of thrombi at 1 MHz is demonstrated adjacent the tip of a micropipette in contact with a mesenteric vessel of the mouse. These effects occur at or above therapeutic levels.

Animals↗

PubMedDate not supplied

Abdominal computed tomography in lupus mesenteric arteritis.

We report the abdominal computed tomography (CT) findings in a patient with systemic lupus erythematosus who developed signs of an acute abdomen secondary to mesenteric arteritis. Initial CT scan demonstrated ascites and wall thickening of the duodenum and jejunum. After treatment with high dose intravenous steroids, follow-up CT scan demonstrated a normal duodenum and small bowel. This is the first surgically proven case of lupus mesenteric arteritis resulting in bowel ischemia that is demonstrated on CT before and after medical therapy. Lupus mesenteric arteritis should be included in the differential diagnosis of causes of bowel wall thickening and ischemia, especially if mesenteric vessels appear prominent.

Abdomen, Acute↗

PubMed1998

Magnetic resonance angiography of mesenteric arteries. A review.

There has been continued development of MRI techniques for evaluating mesenteric vascular disease. Contrast-enhanced magnetic resonance angiography (MRA) can provide reproducible high resolution, high contrast images of the arterial and venous mesenteric vasculature and may allow detection of segmental ischemia by detection of segmental delayed mesenteric or bowel wall enhancement. Cine phase-contrast MRA can provide additional information about the rate and volume of flow within the major mesenteric arteries and veins. Real-time MRI can provide interactive visualization of the mesenteric vessels in any plane, and with suitable bowel contrast, it can be used to monitor global and segmental small bowel motility. With in vivo MR oximetry, flow independent measurements of the T2 relaxation of blood allow the oxygen saturation of the mesenteric circulation to be determined. These MR techniques can be combined for evaluating both anatomic and functional aspects of the mesenteric circulation.

Blood Flow Velocity↗

PubMed1996

Vascular and cardiac protection by ramipril in spontaneously hypertensive rats: prevention versus regression study.

The effect of chronic oral treatment with the angiotensin converting enzyme (ACE) inhibitor ramipril at antihypertensive and sub-antihypertensive doses, on vascular morphology and function as well as left ventricular hypertrophy (LVH) and cardiac capillary length density was investigated in spontaneously hypertensive rats (SHR). Treatment was commenced before hypertension developed (prevention study) or in adult animals with established hypertension (regression study). In both studies, high-dose ramipril reduced ACE activity in plasma, heart and aorta, normalised blood pressure, and prevented LVH or caused regression of LVH. Low-dose ramipril did not prevent the development of hypertension or LVH, but caused an increase in cardiac capillary length density. In adult hypertensive animals, low-dose ramipril did not reduce blood pressure but caused regression of LVH. In both studies, vascular function as tested in the aortic vessels was improved not only after high- but also after low-dose ACE inhibitor treatment: an inhibition of vascular ACE was associated with attenuated vasoconstrictor responses to norepinephrine and enhanced dilator responses to acetylcholine and bradykinin. A reduction of vascular hypertrophy/hyperplasia in the mesenteric vessels was achieved by the antihypertensive dose of ramipril in the prevention but not the regression study. Our data demonstrate that an improvement of vascular function in SHR can be achieved by chronic ACE inhibition with ramipril independently of structural changes and of the antihypertensive action exerted by the drug. LVH was reduced even at a sub-antihypertensive dose of ramipril in the regression but not the prevention study. In the prevention study, however, low-dose ramipril, like high-dose ramipril, was able to protect the heart by preventing cardiac microvascular rarefaction.

Acetylcholine↗

PubMed1985

Chronic mesenteric ischemia in childhood and adolescence.

Chronic mesenteric ischemia is uncommon in the atherosclerotic age group but is particularly rare in childhood. Because of the nonspecific nature of symptoms produced and absence of pathognomonic findings by physical examination or by routine laboratory testing, its recognition is difficult and its true incidence is unknown. Four children treated for chronic mesenteric ischemia in our center demonstrated the spectrum of clinical presentations and operative considerations important in the management of this uncommon malady. Ages at presentation ranged from 30 months to 17 years. These presentations ranged from clinically silent ischemia in the 30-month-old child to evolving gastrointestinal infarction in the 17-year-old adolescent. Coexistence of abdominal aortic coarctation and/or renal artery stenoses was present in three of the four children. Successful bowel revascularization was achieved by superior mesenteric artery revascularization alone in three children (reimplantation in two and a bypass in one) and by multiple celiac and superior mesenteric artery bypasses in one. Delayed distal small bowel and proximal colonic resection was required in one child. This experience increases awareness that mesenteric ischemia does occur in childhood and is a rare but potentially lethal cause of abdominal complaints in children. Finally, the finding of both renal and visceral artery disease in three of the four patients underscores the need for adequate evaluation of mesenteric vessels before renovascular procedures are undertaken in this age group.

Adolescent↗

PubMed1992

[Comparison of the inhibitory effect of diltiazem on neurogenic contractions in the mesenteric arteries and veins].

The effect of diltiazem on the magnitude of isometric contractions induced by electric stimulation of intramural nerves (4Hz) was studied on isolated rings of the mesenteric artery and vein of the dog and rabbit. Diltiazem in concentrations of 10(-5) mol/l and above inhibited neurogenic contractions of the mesenteric artery and vein of the dog in a dose-dependent manner. Inhibition of contractions of the mesenteric vein was found to be more pronounced than that of contractions of the mesenteric artery. In the mesenteric vessels of the rabbit, diltiazem in concentrations of 10(-6) and above inhibited neurogenic contractions, and again more markedly in the veins than in the arteries. On comparing the inhibition of contractions in the two animal species studied, the contractions of the mesenteric vein of the rabbit were found to be more intensely inhibited than those of the dog vein. Diltiazem inhibited also phentolamine-resistant neurogenic contractions of the mesenteric artery. The established differences in the magnitude of neurogenic contraction inhibition may presumably be accounted for by quantitative differences in adrenergic innervation of mesenteric arteries and veins, as well as by differences in the magnitude of the contraction component dependent on extracellular calcium which is greater in the veins than in the arteries. This may also explain the more pronounced inhibition of neurogenic contractions in the veins compared to arteries.

Adrenergic Fibers↗

PubMed1997

Laparoscopic infrared imaging.

A system was developed to determine the potential role of infrared imaging as a tool for localizing anatomic structures and assessing tissue viability during laparoscopic surgical procedures. A camera system sensitive to emitted energy in the midinfrared range (3-5 micron) was incorporated into a two-channel visible laparoscope. Laparoscopic cholecystectomy, dissection of the ureter, and assessment of bowel perfusion were performed in a porcine model with the aid of this infrared imaging system. Inexperienced laparoscopists were asked to localize and differentiate structures before dissection using the visible system and then using the infrared system. Assessment of bowel perfusion was also conducted using each system. Infrared imaging proved to be useful in differentiating between blood vessels and other anatomic structures. Differentiation of the cystic duct and arteries and transperitoneal localization of the ureter were successful in all instances using the infrared system when use of the visible system had failed. This system also permitted assessment of bowel perfusion during laparoscopic occlusion of mesenteric vessels. These initial studies demonstrate that infrared imaging may improve the differentiation and localization of anatomic structures and allow assessment of physiologic parameters such as perfusion not previously attainable with visible laparoscopic techniques. It may thus potentially be a powerful adjunct to laparoscopic surgery.

Animals↗

PubMedDate not supplied

CT appearance of diffuse mesenteric edema.

The extent of pathologic processes involving the mesentery is frequently difficult to assess by clinical examination and standard radiography. Contrast studies of the gastrointestinal tract only identify the effect of these processes on adjacent opacified bowel loops and frequently underestimate the extent of mesenteric pathology. Computed tomography has previously been used to characterize various mesenteric abnormalities, most often secondary to malignant or inflammatory disease. We report the characteristic CT appearance of diffuse mesenteric edema in 14 patients. Eleven patients had documented hypoalbuminemia, two patients superior mesenteric vein thrombosis, and one patient cirrhosis. The CT findings that allowed confident diagnosis of this entity include increase in density of the mesenteric fat, poor definition of segmental mesenteric vessels, relative sparing of the retroperitoneal fat, and association with subcutaneous edema.

Edema↗

PubMed1980

Peripheral dopamine receptors.

Dopamine produces dilation predominantly in renal and mesenteric vascular beds. An action on a specific receptor has been confirmed in vitro using a perfused canine mesenteric vessel preparation. Reductions in resistance produced by dopamine are selectively inhibited by methylergometrine (pA2 = 8.3) and sulpiride (pA2 = 5.6). Evidence is accumulating which suggests that vascular dopamine receptors are innervated. Periaterial nerve stimulation in anesthetized dogs produces increases in blood flow in the superior mesenteric artery which are not influenced by atropine and propranolol but are inhibited by haloperidol. Dopamine receptors are also present at sympathetic ganglia and sympathetic nerve terminals. Inhibition of noradrenaline release resulting from stimulation of these receptors may make an important contribution to the depressor effects of dopamine receptor agonists in anesthetized animals and in man. Reductions in blood pressure induced by bromocriptine and other long-acting dopamine receptor stimulants are frequently associated with reductions in heart rate, but not always with a corresponding depression of myocardial contractile force. This phenomenon may be explained by a selective distribution of prejunctional receptors in sympathetic neurons innervating the sinus node.

Animals↗