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At least 973 records · Page 54Linked to original sources
PubMed1996

[An experimental model of hepatointestinal transplant in the pig with clinical applications].

A model of experimental hepatointestinal transplant in pigs, with clinical applications is presented. Ten animals received a graft composed by the liver and the full length of the small bowel. Two pigs died during the transplant and in eight the surgical procedure was well tolerated with a good revascularization of the grafts. The coagulation parameters were normal after the transplant and only minor biochemical disturbances were found. The main difficulties of the surgical technique are related with the poor tolerance of the pig to the portal and caval clamping, and the close relationships of the duodenum, pancreas and distal colon, produced by the 360 degrees anti-clockwise bowel rotation around the mesenteric vessels. Clamping the supraceliac aorta during the implant of the graft keeps the animal hemodynamically stable and makes unnecessary the use of the more complicated veno venous shunt.

Animals↗
PubMed1976

Necrotic colitis in the presence of normal vascularization of the colon.

Necrotic colitis in the absence of organic obstruction of the mesenteric vessels is an extreme and fulminant form of ischemic colitis. This calamity with its high mortality rate usually occurs in patients with pre-existent cardiopathy. It is rare for necrotic colitis to occur as a complication of hypotension, hypovolemia or sepsis. A report is presented of a case of total gangrene of the colon in a patient with hemorrhagic shock. Certain concepts are presented concerning the etiology of non-occlusive intestinal infarction. It is postulated that the fulminant gangrene of the colon is co-induced by Gram-positive rods which are demonstrable even in the deep layers of the colonic wall.

Colitis↗
PubMed1976

[Effect of bradykinin on the microcirculatory bed of the rat small intestine mesentery].

The effect of application and of intravenous injection of bradykinin on the rat mesenteric microcirculation was studied by direct microscopy methods in vivo. Electrophysiological experiments failed to reveal the reaction of the vascular smooth muscle cells to bradykinin. Under the same conditions the dynamics of vasomotions was studied by the image-splitter method. It appeared that the microvascular response to bradykinin application varied and primarily depended on whether the application was primary or repeated. It is suggested that the action of bradykinin on the mesenteric vessels was mediated through the other vasoactive agents.

Animals↗
PubMed1998

Vascular wall reactivity in conductance and resistance arteries: differential effects of insulin resistance.

Insulin resistance is associated with an increased risk of cardiovascular disease that is probably related to abnormalities of vascular wall function. The JCR:LA-cp rat is a unique animal model of human vascular disease that exhibits a profound insulin resistance, vasculopathy, and cardiovascular disease, and allows study of the relationships between insulin resistance and vascular function. Conductance and resistance arteries serve different functions, thus vascular disease may affect these types of artery differently. Concentration-response curves to norepinephrine, phenylephrine, and acetylcholine were studied in conductance vessels (aortic rings) and resistance vessels (mesenteric arteries) from 12-week-old male obese and lean JCR:LA-cp rats. The aortic rings and mesenteric arteries from obese rats showed increased maximal response to phenylephrine compared with those from lean rats, whereas only the mesenteric arteries from obese rats showed increased maximal response to norepinephrine. In aortic rings, relaxation to acetylcholine was similar for both genotypes, but the mesenteric arteries of obese rats showed impaired relaxation to acetylcholine. We conclude that the sensitivity to vasoconstriction is enhanced in aortic rings and mesenteric arteries of obese male JCR:LA-cp rats, but endothelial function is impaired only in the mesenteric resistance arteries of these animals. Hence functional aberrations in the obese, insulin-resistant state are more pronounced in mesenteric resistance arteries than in a major conductance artery.

Acetylcholine↗
PubMedDate not supplied

[Anterior resection of the rectum via laparoscopy].

Of the newer laparoscopic procedures for colorectal cancers the abdominoperineal resection of the rectum was previously communicated in this journal. The laparoscopic anterior resection is a more technically demanding operation. We report the case of 63 years old women with a rectal cancer at 9 cm from the anus. The procedure was realised under general anaesthesia, with a urinary catheter in place. An blunt obturator was introduced into the uterine cavity and used to manipulate the uterus during the procedure. After establishing of the pneumoperitoneum, a 30 degrees telescope was introduced through the umbilical port (10 mm). The 30 degrees telescope allows visualization of the splenic flexure and rectal side wall. The main steps of the procedure were the exploration of the abdominal cavity, mobilization of the descendent colon and sigmoid, exposure of the left ureter, division of the left sided peritoneal leaf and division of the inferior mesenteric vessels. The anterior dissection of the rectum was facilitated by manipulation of the uterus. The rectum was then mobilized with the "abdominalization of the tumor". A 5 cm left paramedian vertical incision was performed; through this incision a stapler was introduced and the rectum was transected 5 cm under the tumor. The rectum with the tumor, the sigmoid and mesosigmoid were exteriorized through the incision; the sigmoid was divided with a linear stapler cutter 20 cm above the tumor and the specimen was removed extracorporeally. The anvil of a circular stapler was secured in the left colon and returned in the abdominal cavity. The body of the stapler was inserted into the rectal stump through the anus and connected intracorporeally to the anvil. The postoperative evolution was simple; flatus and feces were passed at 48 hours. The patient was discharged to home after 6 days, 13 months after operation she has no morbidity.

Adenocarcinoma↗
PubMed1998

Paraduodenal hernia.

An internal hernia is the protrusion of a viscus through a normal or abnormal opening within the confines of the abdominal cavity. Internal hernias account for 0.2 to 0.9 per cent of all cases of intestinal obstruction. Paraduodenal hernias are relatively rare congenital malformations and account for 30 to 53 per cent of all internal hernias. They result from incomplete rotation of the midgut, with part of the small intestine trapped posterior to the mesocolon. Right and left paraduodenal hernias are distinct and separate entities, varying not only in anatomic structure but also in embryological origin. Symptoms are often vague, and a high index of suspicion is required to make the diagnosis. This entity should be considered whenever atypical abdominal symptoms are present. A CT scan or barium upper gastrointestinal radiography provides the best preoperative evidence of this condition, although ultrasonography and plain films are also useful. Elective repair of such a hernia should always be performed to avoid bowel incarceration or strangulation. An understanding of the anatomy of these hernias facilitates the surgery and is necessary in decreasing the likelihood of complications. Careful reduction of the hernia and surgical repair will avoid injury to the major mesenteric vessels juxtaposed to the hernial orifice. The surgical management of three patients, who were diagnosed preoperatively with this condition, is described with a review of its pathogenesis and present surgical treatment.

Adult↗
PubMed1998

[A case of microcystic cystadenoma treated by duodenum preserving pancreatic head resection].

Cystic neoplasms of the pancreas constitute about 9% of all cystic lesions of the pancreas and less than 1% of all pancreatic neoplasms. The case of a 70 years-old woman with microcystic cystadenoma is reported. CT-scan of the abdomen diagnosed a 5 cm multilocular septated cyst, with calcifications in the context, localized in the head-uncinate process of the pancreas. The mass was well separated by a sharp cleavage plane with portal vein and superior mesenteric vessels. An ERCP showed cephalic symmetrical stenosis (diameter 3 mm) of the main pancreatic duct (MPD), mildly dilated in the remaining tract (diameter 6 mm). An intraoperative biopsy of the cystic wall was performed. Therefore, it was decided to proceed with a duodenum-preserving resection of the head of the pancreas (DPPHR), including the stenosis tract of the MPD in the surgical specimen. The reconstructive procedure consisted, by i.v. jejunal loop transposition, in a side-to-side pancreatico-jejunostomy, including in the anastomosis both corpocaudal stump and the resection cavity of the pancreatic head, and an end-to-side Roux-en-Y jejuno-jejunostomy. With respect to long-lasting pain relief and preservation of the endocrine and exocrine functions of the pancreas, DPPHR is a highly effective surgical procedure with a low early and late morbidity and mortality due to limited surgical resection. This technique, introduced into surgical practice by Beger, is indicated in patients with chronic pancreatitis with an inflammatory mass in the head of the pancreas. The authors conclude that this procedure can be performed also in case of pancreatic benign tumors, as microcystic cystadenoma. Advantages of this technique makes DPPHR an attractive alternative to Pylorus-Preserving-Pancreatico-Duodenectomy (PPPD).

Aged↗
PubMed2004

Quantification of alpha-subunit isoforms of Na,K-ATPase in rat resistance vessels.

AIM: Rat mesenteric resistance vessels (RV) were characterized with respect to concentration of individual alpha-subunit isoforms of Na,K-ATPase. METHODS: Total vessel homogenates were used to avoid any loss or subfractionation of membranes. They were applied to sodium dodecyl sulphate gels and, for calibration, in parallel lanes were run purified rat Na,K-ATPase preparations with known isoform distribution and content. The capacity per mg protein for Na+-dependent 32P-phosphorylation of Na,K-ATPase isolated from rat kidney was used for alpha1 calibration and that for high-affinity (3H)ouabain binding of Na,K-ATPase isolated from rat brain was used for (alpha2 + alpha3) calibration. Western blots containing homogenate proteins and reference enzyme were incubated with isoform-specific antibodies and radiolabelled secondary antibodies. The signals from adjacent alpha spots were used for qualitative and quantitative characterization of rat vessels. RESULTS: A concentration of 100.7 +/- 14.4 pmol (n = 11) per g wet weight of the alpha1-isoform containing Na,K-ATPase was found in RV from 12-14-week rats. A much lower and more unreliable content of alpha2- and alpha3-isoforms was found. These ouabain-sensitive isoforms seem to represent a maximum of 5-10% each compared with the ouabain-insensitive rat alpha1-isoform. CONCLUSIONS: The isoform pattern in RV, in which the isoform with high/intermediate Na+-affinity is the absolutely dominating one representing nearly all sodium pumps in this tissue, is very different from that seen in rat skeletal muscles. Due to the high content of the ouabain-insensitive alpha1-isoform in rat RV this species would seem a less relevant model in studies addressing a role of cardiac glycosides and putative endogenous ouabain-like factors in hypertension.

Animals↗
PubMed1989

Vascular remodeling in the growth hormone transgenic mouse.

Using mice transgenic for the growth hormone gene (TGHM), we have studied the effects of a systemic elevation of growth hormone on vascular growth with the aim of investigating the role of vascular mass changes in producing hypertension. In contrast to human acromegaly or gigantism, there was no elevation of blood pressure in TGHM, but there were significant increases in vascular wall mass. In accordance with a presumably increased perfusion of larger organs, the medial cross-sectional areas of thoracic aorta and mesenteric resistance vessels were greater in the TGHM. These differences could be normalized in the aorta by body weight and in the mesenteric vessel by small intestine weight. Furthermore, the brain was not significantly heavier in the TGHM, and their carotid and cerebral vessels also were not larger. Wall-to-lumen ratios were similar in the aorta, carotid, and middle cerebral arteries suggesting that wall stress was the controlling factor in wall thickness. Surprisingly, the mesenteric vessels had increased wall-to-lumen ratio, which was similar to that seen in hypertensive vascular remodeling but in a normotensive animal. In an attempt to explain this finding it was noted that the pattern of mesenteric vascular networks and even organized structure within the vessel wall itself appeared to be fixed, perhaps by genetic mechanisms. Thus, vascular network structure may be a potentially limiting factor in the ability of the vessel wall to remodel and may have been responsible for the greater wall-to-lumen ratio in TGHM mesenteric vessels. A similar situation in human acromegaly or gigantism could result in a circulation marginally able to correct for other demands on blood flow resulting in about one third of cases being hypertensive.

Animals↗
PubMed1995

Endothelium-independent vasoconstricting and vasodilating actions of halothane on rat mesenteric resistance blood vessels.

BACKGROUND: Whether volatile anesthetics produce changes in vascular resistance and blood flow because of direct effects on vascular tissue is unclear. Direct vasoconstricting and vasodilating actions have been demonstrated in isolated conductance arteries in vitro, but there is little information regarding direct effects on the small vessels that mediate resistance and flow changes in vivo. METHODS: We investigated the actions of halothane on 50-200 microM branches of the rat mesenteric artery that were cannulated and studied in vitro. The vessels were pressurized to 60 mmHg, and vascular dimensions were continuously monitored using a computer-based real-time image analysis system. The vessel bath was perfused with HCO3(-)-buffered saline (37 degrees C) equilibrated with 95% O2/5% CO2 (+/- halothane). The vascular endothelium was mechanically removed before cannulation in some vessels. RESULTS: In unstimulated vessels, halothane had a concentration-dependent vasoconstricting action (EC50 = 0.45 mM approximately 1.5 vol% at 37 degrees C) that was largely transient and was similar to that produced by caffeine. Both halothane and caffeine constrictions were unaffected by bath [Ca2+], nifedipine (1 microM) or Cd2+ (100 microM) and were abolished by ryanodine (10 microM). In addition, caffeine responses were attenuated by halothane in a concentration-dependent manner (EC50 = 1.6 mM). In vessels preconstricted with KCl (40 mM) or phenylephrine (10(-6) M), halothane produced transient constriction followed by concentration-dependent vasodilation. Ryanodine, which abolished halothane constrictions, had little effect on the amplitude of KCl- or phenylephrine-induced constrictions or the vasodilating action of halothane. Removal of the endothelium likewise had little effect on the vasoconstricting or the vasodilating actions of halothane in unstimulated, KCl- or phenylephrine-constricted vessels. Halothane completely relaxed KCl and phenylephrine constrictions with EC50 values of 0.36 mM (1.2% at 37 degrees C) and 0.75 mM (2.5%), respectively, in intact vessels before ryanodine; 0.25 mM (0.8%) and 0.59 mM (1.9%) in intact vessels after ryanodine; and 0.52 mM (1.7%) and 0.67 mM (2.2%) in endothelium-denuded vessels. CONCLUSIONS: Halothane has endothelium-independent vasoconstricting and vasodilating actions in isolated mesenteric resistance blood vessels. The vasoconstricting action appears to involve halothane-induced Ca2+ release from caffeine/ryanodine-sensitive intracellular store(s). The vasodilating action in phenylephrine- or KC1-constricted vessels is independent of the Ca(2+)-releasing action and most likely involves an effect(s) on sarcolemmal-dependent Ca2+ signaling (e.g., extracellular Ca2+ influx) and/or Ca2+ activation of contractile proteins. The magnitude of both the vasoconstricting and the vasodilating actions of halothane in these vessels at clinically relevant concentrations suggests these direct actions contribute to the overall cardiovascular effects of halothane in vivo.

Animals↗
PubMed1995

Calcitonin gene-related peptide mediates acetylcholine-induced endothelium-independent vasodilation in mesenteric resistance blood vessels of the rat.

The role of calcitonin gene-related peptide (CGRP)-containing vasodilator nerves in acetylcholine chloride (ACh)-induced vasodilation was studied in the perfused mesenteric vascular bed isolated from the rat. Bolus infusions of ACh at smaller doses (0.1 and 1 nmol) produced rapid and short-lived vasodilation. However, larger doses (10 and 100 nmol) of ACh caused a rapid and subsequent long-lasting vasodilator response in which the duration of vasodilation was prolonged in a concentration-dependent manner. Pretreatment with capsaicin (1 mumol/L for 20 minutes) significantly shortened the duration of vasodilator response to ACh but did not affect the initial rapid phase of ACh-induced vasodilation. Chemical removal of the vascular endothelium by perfusion with sodium deoxycholate (1.75 to 1.80 mg/mL) for 30 seconds and subsequent treatment with N omega-nitro-L-arginine (100 mumol/L) to inhibit nitric oxide synthesis abolished the initial rapid vasodilator action of ACh at any given concentration. However, in the same preparation, increasing concentrations (from 1 to 1000 nmol) of ACh produced only the long-lasting vasodilator responses in a concentration-dependent manner. This long-lasting vasodilator response to ACh infusion was abolished by capsaicin pretreatment (1 mumol/L), human CGRP[8-37] (CGRP receptor antagonist, 1 mumol/L), and atropine (muscarinic ACh receptor antagonist, 1, 10, and 100 nmol/L) but not by hexamethonium (nicotinic ACh receptor antagonist, 1 and 10 mumol/L). In the preparations without endothelium, the bolus infusion of ACh (300 nmol for 30 seconds) evoked a long-lasting vasodilation and release of CGRP-like immunoreactivities into the perfusate.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1999

Endogenous calcitonin gene-related peptide suppresses vasoconstriction mediated by adrenergic nerves in rat mesenteric resistance blood vessels.

The role of perivascular calcitonin gene-related peptide (CGRP)-containing nerves in the modulation of adrenergic nerve-mediated vasoconstrictions was studied in the rat perfused mesenteric vascular bed. A frequency-dependent vasoconstriction induced by periarterial nerve stimulation (1-6 Hz) of the bed was significantly potentiated by perfusion of 1 microM CGRP-(8-37) (CGRP receptor antagonist) or to a similar extent after treatment with 500 nM capsaicin. In the preparations treated with capsaicin, CGRP-(8-37) caused a small potentiation of periarterial nerve stimulation-induced vasoconstriction. Exogenous CGRP (0.1-1 nM) concentration-dependently attenuated the augmented vasoconstriction in response to periarterial nerve stimulation after treatment with capsaicin. However, exogenous CGRP (1 nM) did not attenuate the periarterial nerve stimulation-induced vasoconstriction in the bed untreated with capsaicin. These results suggest that endogenous CGRP, which is released from CGRP-containing nerves, suppresses the adrenergic nerve function involved in mechanisms regulating the tone of resistant blood vessels.

Animals↗
PubMed1986

Perfusion of the intact and partially isolated rat mesenteric vascular bed: application to vessels from hypertensive and normotensive rats.

In the present study, we utilized 2 perfused mesenteric vascular bed preparations in an examination of the responses of mesenteric vessels from spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. One preparation involved perfusion of the mesenteric vascular bed dissected free from the intestine. The second preparation was essentially similar, with the exception that the intestine and the small arterioles feeding the jejunum were intact. The results suggested that the small vessels offer a significant contribution to the mechanical resistance to perfusion in the mesenteric vasculature and are important in the neurogenic responses of this preparation. In contrast, the arterioles in the arcade supplying the jejunum play only a minor role in the responses of the mesenteric vascular bed to intraluminally injected vasoactive substances. It was found that mesenteric preparations from SHR rats responded more forcefully to intraluminally administered norepinephrine and potassium, regardless of whether the intestine was absent or present. Similarly, the responses of mesenteric preparations to electrical nerve stimulation were greater in preparations from SHR rats, particularly when the intestine was present. It is concluded that the perfused mesenteric vasculature from SHR rats is more responsive to vasoactive substances and nerve stimulation and that this feature is not exclusively dependent upon a contribution to contraction by the arterioles supplying the jejunum.

Animals↗
PubMed1991

Blood flow stasis induced by cw-Nd:YAG laser irradiation: comparative morphology of mesenteric and choroidal vessels in pigmented rabbits.

cw-Nd:YAG laser radiation was effective in producing blood flow stasis within arteries (35-40 microns in diameter) of pigmented rabbit mesentery (beam spot size: 80 microns; fluence: 2 x 10(4) J cm-2) and choroid (beam spot size: 200 microns; fluence: 6 x 10(2) J cm-2). However, the mechanism by which this was achieved differed in each case, and depended upon the energy absorbing structures present in the irradiated tissue. In non-pigmented tissue, such as the mesentery, haemoglobin represents the primary absorption centre, and the temperature attained within the vessel lumen (as inferred from morphological changes) is sufficient to denature plasma proteins, in particular fibrinogen, which consequently occlude the vessel lumen and arrest bleeding. In pigmented tissue, such as the choroid, melanocyte granules represent the primary absorption centre, which is thus shifted from the vessel lumen to the stroma. The temperature rise achieved within the vessel lumen is consequently lower, as evidenced by the absence of plasma protein denaturation. Blood flow stasis nonetheless occurs, but is triggered according to the normal haemostatic mechanism.

Animals↗
PubMed2000

Generation of pro-inflammatory and anti-inflammatory cytokines in the gut in zymosan-induced peritonitis.

In major systemic inflammation such as severe peritonitis, various pro-inflammatory cytokines, such as TNF-alpha, IL-1 beta and IL-6, play important roles in the development of multiple organ dysfunction syndrome (MODS). The purpose of this study was to investigate the outflow of pro-inflammatory and anti-inflammatory cytokines from the efferent mesenteric lymphatic vessels under peritonitis. Mesenteric lymph samples were collected from adult male rats at 2, 4, 6, 8 and 10 hr after an intraperitoneal injection of zymosan at a dosage of 0.1 mg/g (non-lethal dose) or 0.5 mg/g (lethal dose). Blood samples were obtained at 10 hr after zymosan administration. The amounts of drained TNF-alpha and IL-6 in the lymph peaked at 2-4 hr and 4-8 hr after zymosan administration, respectively. The amounts of drained IL-10 in the lymph gradually increased until 10 hr. The amounts of drained TNF-alpha and IL-10 in the mesenteric lymph were significantly correlated with the dosage of zymosan. In conclusion, under intraperitoneal inflammation, pro-inflammatory cytokines (TNF-alpha and IL-6) increased in the mesenteric lymph and were drained into circulation. IL-10, one of the anti-inflammatory cytokines, also increased in the mesenteric lymph after several hours' delay and its increase was remarkable in several inflammations. These findings suggested that the gut might be one of the pro-inflammatory and anti-inflammatory cytokine-generating organs under peritonitis. The lymph-drained amounts of each cytokine under peritonitis are considered to differ with the time or severity of inflammation, which may cause different conditions in patients due to the imbalance of pro-inflammatory and anti-inflammatory cytokines.

Animals↗