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PubMed1993

Clinical course, morphology, and treatment of chronically rejecting small bowel allografts.

As acute rejection episodes are most frequently prevented or controlled in clinical organ transplantation, chronic rejection processes have become the major reason for late dysfunction and eventual loss of the allograft. The recent reports on successful clinical intestinal transplantation prompted us to investigate chronic rejection processes that may arise after the initial control of acute rejection. Using the strongly histoincompatible ACI-->LEW rat strain combination and serial graft biopsies after limited initial immunosuppressive therapy with cyclosporine, we defined the clinical and pathomorphologic course of chronic rejection of orthotopic small bowel allografts. Differing from acute rejection, the bowel wall (especially the mucosa and submucosa) was not the primary target of chronic rejection. We observed progressive destruction of the Peyer's patches and the mesenteric lymph nodes of the graft--a process which began during the 4-week course of CsA--and infiltration and destruction of graft mesenteric vessels. Testing the immunosuppressive drugs FK506 and CsA for their efficacy to ameliorate ongoing chronic rejection, we found that a short course (5 days) of FK506 was more effective than a second 4-week course of CsA. However, while allograft function recovered sufficiently to allow a temporary improvement of the recipient's global nutritional state, pathomorphologic graft changes failed to reverse substantially. Eventually all grafts failed due to progressive chronic rejection.

Animals↗
PubMed1999

Lisofylline ameliorates intestinal mucosal barrier dysfunction caused by ischemia and ischemia/reperfusion.

In an effort to determine whether treatment with lisofylline (LSF) ameliorates intestinal barrier dysfunction in rats subjected to mesenteric ischemia and reperfusion (I/R), regional mesenteric vessels were occluded for 60 min and then unclamped for 60 min more. In Protocol 1, intravenous LSF (15 mg/kg bolus then 10 mg/kg/h) was administered 5 min before ischemia. In Protocol 2, LSF (same dose) was given 1 min before reperfusion. Controls received an equivalent volume of Ringer's lactate solution. Permeability was assessed by determining the mucosal-to-serosal clearance of fluorescein isothiocyanate-conjugated dextran (4 kDa) in everted ileal gut sacs incubated ex vivo. In Protocol 1, LSF treatment during ischemia ameliorated mucosal barrier dysfunction; mean +/- SEM clearances for the LSF and Ringer's lactate solution groups after 60 min of ischemia were 34.4+/-6.1 and 64+/-7.1 nL/min/cm2, respectively; p = .007. Clearances after reperfusion were the same in the two groups. In Protocol 2, LSF treatment just before reperfusion ameliorated barrier dysfunction measured 60 min after the restoration of blood flow; clearances for the LSF and Ringer's lactate solution groups were 23.1+/-3.8 and 40.2+/-4.5 nL/min/cm2, respectively; p = .012. Treatment with LSF did not affect intestinal levels of reduced glutathione or adenosine triphosphate or the extent of histological damage to the mucosa after I/R. Nevertheless, villus height was greater in animals treated with LSF than RLS prior to ischemia in Protocol 1 (250+/-37 and 160+/-15 microm, respectively; p = .04) and during reperfusion in Protocol 2 (170+/-21 and 82+/-7 microm, respectively; p = .002). We conclude that LSF is effective in reducing both ischemia- and I/R-induced gut barrier dysfunction, possibly due to a mechanism related to preservation of villus height.

Adenosine Triphosphate↗
PubMed1999

Effect of mesenteric ischemia and reperfusion or hemorrhagic shock on intestinal mucosal permeability and ATP content in rats.

In a reductionist in vitro system, intestinal epithelial permeability appears to be dependent on cellular ATP content. In order to extend these prior observations, we used rat models of mesenteric ischemia/reperfusion (I/R) and pressure-controlled hemorrhagic shock to test the hypothesis that intestinal barrier function is directly proportional to tissue ATP content. I/R was induced by clamping the mesenteric vessels for 60 min followed by 60 min of reperfusion. Normal, ischemic, and reperfused ileal segments were prepared from each rat (n = 12). Hemorrhagic shock was induced by bleeding rats (n = 9) to a mean arterial pressure of 30 mmHg and maintaining this pressure for 4 h by infusing Ringer's lactate solution as necessary. Ileal segments were harvested before induction of hemorrhage and at 1 h intervals thereafter. Everted gut sacs were prepared to measure the mucosal-to-serosal passage of fluorescein-conjugated dextran (FD4; M.W. = 4 kDa). Tissue ATP levels were determined using a luciferase assay. FD4 clearance rates were plotted as a function of tissue ATP content. Linear regression analyses showed a strong inverse relationship between intestinal permeability and tissue ATP level in rats subjected to I/R (r2 = 0.78; P < 0.001) or hemorrhage (r2 = 0.82; P < 0.001). These data support the idea that ATP content is a determinant of intestinal epithelial barrier function in vivo.

Adenosine Triphosphate↗
PubMed1997

Evaluation of trauma care in a developing country highlighted by a major aircraft accident.

The aim of this study was to evaluate the day-to-day trauma care in a developing country highlighted by a major accident. In this accident, early management was not carried out according to triage principles. Scene mortality and in-hospital mortality were 72% (n = 55) and 14% (n = 3), respectively. Overall mortality rate was 76%. Five survivors were minor wounded. Three laparotomies, one thoracotomy and three tube thoracostomies were performed in the acute phase. Skeletal injuries, mainly rib fractures (43.3%) and haemothorax (10.8%), were the most frequent pathologies seen. One liver laceration, one splenic rupture, one intraabdominal bleeding due to rupture of mesenteric vessels, two major cranial traumas and an abruptio placenta were the other pathologies. The missed injury rate in this accident was 16% (n = 6). It is concluded that the missed injuries in this incident reflect the inadequacy of trauma care in the rural area of the developing country.

Accidents, Aviation↗
PubMed2005

Pancreaticoduodenectomy in adults with congenital intestinal rotation disorders.

Congenital intestinal malrotation is a developmental anomaly resulting from interruption of the physiological herniation and return to the abdominal cavity of the midgut during the 6th to 10th week of embryological development. Normal vascular and anatomic relationships used as landmarks during pancreaticoduodenectomy (PD) are altered in patients with congenital malrotation. We present 3 cases of PD in adults with congenital intestinal rotation disorders. Three adult patients with congenital rotational disorders required PD. Two of these patients had bilio-pancreatic tumors, and 1 cadaveric donor underwent total pancreatectomy during pancreas allograft procurement. All patients had arterial and venous anomalies around the celiac trunk and mesenteric vessels, respectively. The midgut and hindgut in each case were shifted toward opposite sides of the abdominal cavity. Modifications to the standard approach to PD were made, and outcomes were favorable in each case. Each patient showed anatomic abnormalities with the need for identifying vascular structures through their expected (or projected) course and location before parenchymal division or ligation of any vessel. This approach becomes crucial in cases of vascular anomalies, such as ones occurring in congenital malformations, and can be used in similar situations encountered during pancreaticoduodenectomy.

Adult↗
PubMed1976

The migration of lymphocytes across specialized vascular endothelium. I. The entry of lymphocytes into the isolated mesenteric lymph-node of the rat.

The chain of lymph-nodes in the rat mesentery was isolated and the preparation was perfused via cannulae in the superior mesenteric vessels. The perfusate consisted of serum to which labelled lymphocytes had usually been added. The entry of radioactively labelled lymphocytes from the blood vessels into the lymph-nodes was studied by scintillation counting and autoradiography. It was observed that: (1) In the perfused node labelled lymphocytes localized in and around post-capillary venules in the paracortex as they do early after i.v. injection. (2) The number of lymphocytes which entered the node was directly proportional to the concentration in the perfusate over the range studied. The proportion of cells retained in the node varied considerably around a mean of 11% of lymphocytes reaching it. (3) The isolated lymph-node released few if any lymphocytes into the effluent (venous) perfusate. (4) Large lymphocytes migrated into isolated lymph-nodes slightly more readliy than did small lymphocytes. (5) Unlike intact cells isolated lymphocyte membranes did not adhere to specialized vascular endothelium.

Animals↗
PubMed2005

Indomethacin-induced ileitis is associated with tensiometric, vascular and oxidative changes in the experimental rat model.

BACKGROUND: Indomethacin-induced enteritis is a model of inflammatory bowel disease. MATERIALS AND METHODS: To further characterize this model, rats received two injections of indomethacin (7.5 mg kg(-1)) 24 h apart and histological damage of intestinal mucosa, oxidative stress, alterations of intestinal motility and mesenteric vascular bed (MVB) reactivity were investigated after 5 days. RESULTS: The results show that indomethacin caused several histological and functional changes at the ileal level. In particular, response to carbachol as well as the nonadrenergic-noncholinergic inhibitory response to electrical field stimulation (EFS) was lower in the treated than control rats. Moreover, nitric oxide (NO)-component of the inhibitory response was higher in the treated than control rats. Mesenteric vessels preparations from the treated rats showed increased noradrenaline (NA)-induced perfusion pressure, whereas relaxant responses to acetylcholine, although not significantly reduced in the treated rats, had a higher nitrergic component. This finding suggests that vascular dysfunction may contribute to chronic inflammation. Indomethacin injection also determined acute and severe oxidative stress in ileum mucosa. CONCLUSIONS: In conclusion, our study contributes to further characterize the rat model of indomethacin-induced enteritis and suggests that it is suitable for drug screening in rats, as this model can be obtained in a very short period and is simple and reproducible.

Acetylcholine↗
PubMed1999

Comparative effects of mibefradil and other calcium antagonists on resistance arteries of different end organs.

The biphasic contractile responses of rat isolated mesenteric, renal, coronary and basilar small arteries to potassium-induced depolarization were investigated. The tonic phase is assumed to be exclusively the result of L-type calcium channel (LCC) activation, whereas in the generation of the phasic phase T-type calcium channels (TCC) may be involved. In order to evaluate whether TCC blockade has any influence on depolarization-induced contractions the effects of the LCC antagonists nifedipine, diltiazem and verapamil were compared with those of the combined L- and TCC antagonist mibefradil. Small arteries (size 393.6 +/- 4.8 microns, n = 104) were dissected from the respective organs of male Wistar rats (300-350 g) and studied in an isometric wire myograph. The effects of increasing concentrations of the calcium antagonists on repetitive potassium-induced contractions were quantified by means of cumulative concentration-response curves. A comparison was made with mesenteric vessels of SHR and WKY for nifedipine and mibefradil. Nifedipine was the most potent compound in blocking both the phasic phase (reduction 66-77%) and the tonic phase (IC50 = 1.1-5.4 nM). The effect of mibefradil on the phasic response was comparable to that of verapamil and diltiazem. With respect to the tonic response mibefradil was comparable to verapamil (IC50 = 19.6-178.9 nM). These findings indicate that the TCC blockade does not contribute to the vasodilator effect of mibefradil under the conditions investigated.

Animals↗
PubMed2006

Increased angiogenesis and permeability in the mesenteric microvasculature of rats with cirrhosis and portal hypertension: an in vivo study.

BACKGROUND: In vivo evidence for angiogenesis in the splanchnic vasodilation in portal hypertension (PHT) and cirrhosis is lacking. Vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) are mediators of angiogenesis. The present study visualises in vivo structural changes (angiogenesis and vascular hyperpermeability) and examines the presence of VEGF and eNOS in the mesenteric microvasculature of animal models of PHT with and without cirrhosis. METHODS: Portal hypertension was induced by partial portal vein ligation (PPVL) and cirrhosis was induced by common bile duct ligation (CBDL) in rats. The mesenteric microcirculation was examined by intravital microscopy. Expression of VEGF, eNOS and CD31 in mesenteric tissue were studied by immunohistochemistry. RESULTS: An increased mesenteric angiogenesis was observed in PPVL and CBDL rats compared with Sham-operated and control rats, as shown by intravital microscopy and CD 31 staining. VEGF and eNOS expression was higher in CBDL and PPVL rats compared with control groups and correlated positively with vascular density. Macromolecular leakage was increased in cirrhotic rats compared with control and PPVL rats. CONCLUSION: Our study provides in vivo evidence of an increased angiogenesis in the mesenteric microvasculature of animal models of PHT and cirrhosis. Increased VEGF and eNOS expression in the mesentery of PPVL and CBDL rats may suggest their contribution. Microvascular permeability in the mesenteric vessels was only increased in cirrhotic rats.

Animals↗
PubMed2004

Colonic toxicity of administered drugs and chemicals.

Although uncommon, medication-induced colonotoxicity is important to recognize because medication cessation generally leads to prompt clinical improvement, while medication continuation results in disease exacerbation. This review categorizes the association between medications and colonotoxicity as "well-established" or "probable," according to the following criteria: total number of reported cases, number of different research groups reporting an association, experimental and pharmacologic evidence of an association, and validity of an association in each reported case. Cocaine, ergotamine, estrogen, sodium polystyrene, alosetron, amphetamines, pseudoephedrine, and vasopressin are associated with colonic ischemia. The mechanisms include vasospasm, thrombogenesis, and shunting of blood from mesenteric vessels. Narcotics, phenothiazines, vincristine, atropine, nifedipine, and tricyclic antidepressants are associated with colonic pseudo-obstruction. The mechanisms include antagonizing prokinetic neurotransmitters, stimulating antikinetic neurotransmitters, promoting dysmotility, relaxing smooth muscle, and injuring enteric neurons. Numerous antibiotics are associated with pseudomembranous colitis; ampicillin is associated with hemorrhagic colitis; chemotherapy is associated with neutropenic colitis; and deferoxamine is associated with Yersinia enterocolitis. Mechanisms of these toxicities include altering normal bowel flora, weakening immunologic defenses, promoting microorganism virulence, and mucosal injury. Gold compounds, nonsteroidal antiinflammatory drugs, alpha-methyldopa, salicylates, and sulfasalazine are associated with an inflammatory or cytotoxic colitis. The mechanisms include direct mucosal cytotoxicity, antimetabolite effects, or drug allergy. Nonsteroidal antiinflammatory drugs, cyclo 3 fort, flutamide, lansoprazole, and ticlopidine are associated with lymphocytic colitis. The mechanisms include immunologic activation or attenuated immunologic defenses. Chronic cathartic use leads to colonic hypomotility and abdominal distention. Intrarectally administered corrosive compounds can produce a toxic colitis.

Administration, Oral↗
PubMed1985

A 13q- syndrome with extensive intestinal atresia.

The first autopsy case of a 13q- syndrome with extensive intestinal atresia, viz., absence of almost the entire jejunum and ileum, is reported. The absence of the mesentery and the histological properties of the intraperitoneal string-structures composed of some muscle layers resembling the tunica muscularis of the alimentary tract suggest that one of the causative agents of the atresia may be abnormalities of mesenteric vessels.

Abnormalities, Multiple↗
PubMed2002

Roles of erythropoietin in human milk.

UNLABELLED: Erythropoietin (Epo) is one of many biologically active growth factors present in human and animal milk. Accumulating evidence shows important developmental roles for these milk-borne growth factors. Although Epo is present in biologically relevant amounts in mammalian milk, the roles of Epo in milk are incompletely defined. A significant proportion of milk-borne Epo resists proteolytic degradation. Epo receptors (EpoR) have been found on gastric mucosa and intestinal mucosa, and in mesenteric vessel endothelium. Evidence to date shows that intact Epo reaches these local organs, as well as distal organs. After feeding Epo, local gastrointestinal physiological effects are seen in suckling rats. In humans and rats, short-term feeding of high-dose Epo increases reticulocytes, but it is unclear whether sustained treatment increases red cell mass. CONCLUSION: Further work towards understanding the physiological and potential pharmacological roles of enterally administered Epo is necessary.

Animals↗
PubMed1981

Cardiovascular lesions in Sprague-Dawley rats induced by long-term treatment with caffeine.

Male Sprague-Dawley rats were treated with phenacetin, phenazone or caffeine in the diet or with combinations of these chemicals for up to 117 weeks. Twenty of twenty-eight rats receiving caffeine only developed moderate to severe myocardial fibrosis compared with five control rats, in spite of the fact that the control rats had a sixteen weeks longer average life-span. Four caffeine-treated rats had histologic evidence of acute myocardial infarction which was not found in any of the other rats. Forty percent of the rats treated with caffeine only or with caffeine and phenacetin in combination were found to have periarteritis nodosa-like lesions in the mesenteric vessels. Seventy-nine percent of the rats treated with caffeine only and 52 percent of those treated with caffeine and phenacetin died from cardiovascular disease, compared with 17 percent among the control rats. Thus, long-term administration of caffeine to Sprague-Dawley rats is associated with markedly reduced life-span due to cardiovascular disease.

Acetaminophen↗
PubMed1971

The influence of mesenteric denervation on the inhibition of gastric secretion by fat in the intestine.

The inhibitory effect of fat in the upper small intestine was studied in dogs prepared with a Heidenhain pouch, gastric fistula, and jejunal fistula. Gastric secretion was stimulated by a constant intravenous infusion of pentagastrin, and emulsified olive oil was introduced into the jejunum. The small intestine of the dog was denervated by complete transection of the mesentery except for the superior mesenteric vessels. After intestinal denervation inhibition of the vagally innervated stomach was almost abolished while that in the Heidenhain pouch was unchanged. It is concluded that either autonomic innervation is important in the formation of enterogastrone or, more likely, that efferent inhibitory fibres in the vagus to the stomach act synergistically with enterogastrone.

Animals↗
PubMed1991

Left infrarenal region: anatomic variants, pathologic conditions, and diagnostic pitfalls.

Computed tomography (CT) is the preferred method for evaluating the left periaortic infrarenal region. Structures larger than 11 mm in cross-sectional diameter in this region are considered abnormal and should be evaluated for lymphadenopathy, hydroureter, or a vascular abnormality such as venous thrombosis or varicoceles. Normal structures include inferior mesenteric vessels, left gonadal vein and artery, and ureter. The diagnostic process may be complicated by variations in anatomy, including double inferior vena cava, left inferior vena cava, retroaortic left renal vein, circumaortic left renal vein, horseshoe kidney, crossed-fused renal ectopia, renal agenesis, and ureteral duplication. Familiarity with the anatomy of this region and awareness of normal variants are necessary to avoid errors in diagnosis. Radiologists should also be aware of problems in CT technique (nonopacified bowel, dynamic and unenhanced scanning) that can confuse the diagnosis.

Aneurysm↗
PubMed1994

Pathways of nodal metastasis from pelvic tumors: CT demonstration.

Although the normal pathways of lymphatic drainage from the pelvic organs have been well described in the anatomy literature, the pathways of nodal metastasis from individual pelvic neoplasms are not well illustrated in the imaging literature. The authors retrospectively reviewed computed tomographic scans of the abdomen and pelvis in patients with various pelvic neoplasms, including those of the ovary, testis, prostate, cervix, bladder, anorectum, and other sites, to define the pathways of nodal metastasis. In most patients, pathways of nodal metastasis correlated well with the normal lymphatic pathways described in the anatomy literature, including the superficial inguinal pathway; the anterior, lateral, hypogastric, and presacral routes of the pelvic pathway; and the paraaortic pathway. However, there also were various uncommon pathways of nodal metastasis, such as metastasis along the gonadal vessels, mesenteric and mesocolic nodes, posterior iliac crest nodes, and inferior phrenic nodes. Understanding these common and uncommon lymphatic pathways of metastasis will help radiologists detect disease spread from pelvic tumors.

Humans↗
PubMedDate not supplied

Helical CT in the diagnosis of small bowel obstruction.

With recent technologic developments, the role of computed tomography (CT) in the diagnosis of bowel obstruction has expanded. CT is recommended when clinical and initial radiographic findings remain indeterminate or strangulation is suspected. This modality clearly demonstrates pathologic processes involving the bowel wall as well as the mesentery, mesenteric vessels, and peritoneal cavity. CT should be performed with intravenous injection of contrast material, and use of thin sections is recommended to evaluate a particular region of interest. CT is reported to have a sensitivity of 78%-100% for the detection of complete or high-grade small bowel obstruction but may not allow accurate diagnosis in cases involving incomplete obstruction. In such cases, the use of adjunct enteroclysis is indicated. Furthermore, multiplanar reformatted imaging may help identify the site, level, and cause of obstruction when axial CT findings are indeterminate. CT can also demonstrate findings that indicate the presence of closed-loop obstruction or strangulation, both of which necessitate emergency exploratory laparotomy. Unfortunately, these pathologic conditions may be missed, and patients with suspected severe obstruction or bowel ischemia in whom CT and clinical findings are widely disparate must also undergo laparotomy. In general, however, CT allows appropriate and timely management of these emergency cases.

Diagnosis, Differential↗