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PubMed1978

Adrenergic terminal structures in the mesentery of mammals.

This work is devoted to the study of adrenergic terminal structures in the mesentery of mammals (cat, dog). The investigation was performed with the Falck-Hillarp method of catecholamine fluorescence microscopy on total stretch mesentery preparations. The investigation showed that richly developed perivascular plexus constitute the basis of the adrenergic innervation system of the mesentery. In numerous points of these plexuses, single adrenergic fibers or polyaxonal structures are observed to issue into nonvascular areas of the mesentery where after repeated dichotomic division they pass into the preterminal and terminal parts. Being constructed on the principle of extended or restrained arborizations, these innervating structures have a morphological similarity with free sensory nerve endings. In this connection, the question of the possible existence of the sensory (afferent) links in the catecholamine-containing vegetative nerve plexuses is discussed.

Adrenergic Fibers↗
PubMed1987

A morphologic and histochemical study of the mesentery in the guinea pig.

The guinea pig mesentery is a uniform, continuous, thin (18 micron) sheet of connective tissue covered by a single layer of flattened mesothelial cells on both surfaces. Tight and gap junctions provide for cell-to-cell adhesion among mesothelial cells. These cells possess numerous micropinocytotic vesicles; a conspicuous basal lamina separates the mesothelium from the underlying connective tissue. Most of the material found between the two serous coverings consisted of a three-dimensional meshwork of abundant collagenous fibers intermingled with a sparse net of very thin (0.4 micron) elastic fibers. Two distinct populations of collagen fibrils are segregated into different compartments of the mesentery. One population is formed of thick (56 nm) fibrils which associate to form closely packed fibers. The second population, composed of loosely arranged thin (38 nm) fibrils which do not become assembled into fibers, is found underlying the basal lamina that separates the mesothelium from the connective tissue. These observations strongly suggest that the mesentery contains both collagens type I and type III. The guinea pig mesentery contains 6.8 mg of sulfated glycosaminoglycans/g dry weight. Most of these glycosaminoglycans (78%) were identified as dermatan sulfate, whilst the rest (22%) corresponded to heparan sulfate.

Animals↗
PubMed2000

Asbestos in extrapulmonary sites: omentum and mesentery.

STUDY OBJECTIVES: Asbestos fibers have not been reported in tissues from the peritoneal cavity. Therefore, omentum, mesentery, and lung tissues from 20 individuals in whom mesothelioma was diagnosed were analyzed for asbestos bodies and asbestos fibers. DESIGN: Tissue was digested and prepared filters were analyzed by light microscopy and analytical transmission electron microscopy. RESULTS: Asbestos bodies were found in the lungs of 18 individuals, mesentery samples from 5, and omentum samples from 2. Uncoated asbestos fibers were found in lungs of 19 patients, 17 of whom had fibers in at least one extrapulmonary site. The most common asbestos in the omentum and mesentery was amosite. Several features of asbestos found in lung influenced the likelihood of amphibole fibers being found in the omentum or mesentery. Lung features included total amphibole fiber burden, length, aspect ratio, and ferruginous body burden. An increased total ferruginous body burden was strongly associated with increased likelihood of detecting amphiboles in the omentum (p < 0. 05). CONCLUSION: Asbestos fibers reach areas in the peritoneal cavity where some mesotheliomas develop. This study suggests their presence can be predicted based on concentrations and characteristics of fiber burdens in lung tissue.

Aged↗
PubMed1999

Mast cell degranulation and parenchymal cell injury in the rat mesentery.

OBJECTIVE: The objective of this study was to explore the degree of parenchymal cell injury after mast cell degranulation by application of compound 48/80 (CMP 48/80) in the absence of adherent leukocytes in the rat mesentery. METHODS: Rats were rendered leukopenic by injection of an antibody against leukocytes, and the mesentery was superfused with CMP 48/80 during intravital microscopy. The extent of cell injury was determined using a fluorescent cell-viability indicator, propidium iodide (PI). In an additional group, mast cell degranulation with CMP 48/80 was prevented by using the mast cell stabilizer Ketotifen. RESULTS: After a reduction in the number of circulating leukocytes, mast cell degranulation produced a mild increase in parenchymal cell injury. The injury levels significantly increased when individual regions of the mesentery were compared. Stabilization of the mast cells with Ketotifen reduced the injury to below baseline values. CONCLUSIONS: In the absence of leukocyte adhesion to the endothelium, mast cell degranulation contributes to parenchymal cell injury in the mesentery.

Animals↗
PubMedDate not supplied

Malignant fibrous histiocytoma (MFH) of the mesentery: a case report.

BACKGROUND: Primary tumors of the mesentery are rare; only a few cases of malignant fibrous histiocytoma have been reported in the literature. This case report presents the management of a patient with malignantfibrous histiocytoma of the mesentery. CASE REPORT: A 48-year-old woman presented with mild abdominal pain and a palpable tumor in the lower abdomen. Laparatomy revealed a 12x9 cm tumor located in the mesentery and an enlargement of the paraaortic lymph nodes. The tumor was histologically classified as a malignant fibrous histiocytoma, showing a heterologeous picture consisting of large, multinucleated cells and spindle-shaped cells forming a storiform-like growth pattern. A radical excision of the tumor and the lymphnodes was performed and the patient received adjuvant irradiation therapy. Approximately three months later she presented with a great multilobated pelvic mass infiltrating the uterus and the adnexa. The patient underwent total abdominal hysterectomy and bilateral salpingo-oopherectomy to reduce the tumor mass. Two courses of palliative cytotoxic polychemotherapy were applied, but the patient died two months later due to progression of disease. CONCLUSION: Malignant fibrous histiocytoma of the mesentery is an extremely rare, highly malignant neoplasm with early metastatic spread. The treatment of choice is wide surgical excision, while the role of adjuvant chemotherapy and irradiation still remains controversiaL

Female↗
PubMed2005

[Clinicopathological and immunohistochemical study of extra-gastrointestinal stromal tumors arising from the omentum and mesentery].

OBJECTIVE: To explore the clinicopathological and immunohistochemical features of extra-gastrointestinal stromal tumors (EGIST) arising from the omentum and mesentery and to investigate the cellular origin of these tumors, prognostic factors, and the relationships with gastrointestinal stromal tumors. METHODS: Nineteen cases of mesenchymal neoplasms arising from the omentum and mesentery (previously diagnosed as smooth-muscle tumors or schwannomas) were studied morphological with a panel of immunohistochemistry including CD117 and CD34. RESULTS: Among the 19 cases, 14 tumors were confirmed to be EGIST, of which 6 tumors arose from the omentum and 8 cases located at the mesentery. The size of tumors ranged from 3.5cm to 29.0 cm (mean 12.4cm) in diameter. Histologically, there were 9 cases of mainly spindle cell type, 2 cases of mainly epithelioid cell type and 3 cases of mixed cell type. all EGIST expressed CD117 (14/14) and a percentage of them expressed also CD34 (8/14) and/or SMA (6/14), anyhow, all EGIST were negative for desmin and S-100 protein. Six patients with tumors arising from the omentum were all alive without evidence of disease (tumor-free). Among 7 cases with tumors of the mesentery, three patients died of the disease, 1 alive with the disease and 3 patients alive without evidence of the disease. CONCLUSIONS: EGIST were identical by their histological and immunohistochemical features with gastrointestinal stromal tumors (GIST). This tumor may arise from the multipotential mesenchymal stem cells. EGIST have various clinical behavior, and the parameters used for predicting the prognosis of GIST may not be completely suitable for EGIST evaluation.

Actins↗
PubMed1985

Neoplastic modulation of extracellular matrix: proteoglycan changes in the rabbit mesentery induced by V2 carcinoma cells.

Previous studies have shown that the invasion of V2 carcinoma cells in the rabbit mesentery is associated with marked extracellular matrix synthesis leading eventually to an overall increase in mesenteric mass. The purpose of the present study was to investigate the structural and biochemical composition of the extracellular matrix in tumor-free parts of rabbit mesenteries at various stages after intraperitoneal implantation of V2 carcinoma cells. The overall thickness of the tumor-implanted mesenteries increased progressively and peaked at about Day 14, when it was about 8 times greater than the untreated or liver-implanted controls. This was mainly the result of an accumulation of extracellular matrix components. In particular, there was a marked increase in both collagen fibers and proteoglycan granules, as well as filaments, probably hyaluronic acid, as visualized by ruthenium hexammine trichloride. Stereological analysis showed a 6-fold increase in collagen fibers and a significant increase in the density and average diameter of proteoglycan granules. Biochemical analysis revealed a marked elevation in uronic acid content in the tumor-implanted mesenteries. Specifically, they contained 2.6 and 8.6 times the amount of hyaluronic acid and chondroitin sulfate, respectively, than did controls. Furthermore, the relative percentage of chondroitin sulfate was elevated markedly (26 versus 6% in controls). However, the content of heparan or dermatan sulfate did not vary significantly. Stereological analysis of the fibroblasts showed that their absolute number had doubled and that the cell volume of the individual fibroblast had increased markedly. This suggests that the fibroblasts were responsible for the excessive production of the extracellular matrix. These results support the concept that carcinoma cells can modulate their surrounding extracellular environment by stimulating the synthesis of connective tissue in the host mesenchymal cells.

Animals↗
PubMed1979

[Localization of the lamellated corpuscle neurons of the cat large intestine mesentery].

Electrical activity and ultrastructure of lamellated corpuscles (Pacinian corpuscles) of the cat large intestine mesentery were studied 10 days after uni- and bilateral extirpation of the lumbar spinal ganglia. Terminal degenerated in all the receptors, and there were no electrical reactions at bilateral extripation of ganglia L3-L4, they were preserved in some receptors at bilateral extirpation of ganglia L2-L3 and L4-L5 and at unilateral extirpation of ganglia L3-L4. Structure of the receptors and electrical reactions were preserved in all the lamellated corpuscles at bilateral extirpation at the level of L1-L2 and L5-L6. After enucleation of the corpuscles from the large intestine mesentery, in some neurons of ganglia L3-L4, chromatolysis was observed. After the caudal mesenteric nerve was sectioned, there were no electrical reactions in the lamellated corpuscles of the large intestine mesentery. Hence, the sensitive neurons-theri peripheral processes participate in the formation of the lamellated corpuscles of the cat large intestine mesentery-are situated in the lumbar ganglia L3 and L4.

Animals↗
PubMed1995

[The tissue basophils of the rat mesentery under the influence of a permanent magnetic field].

Effect of constant magnetic fields (CMF) of low energies (B = 35 mT, E = 350 Oe) on the system of mesenterial mast cells (MT) was studied by methods of light and electron microscopy in 140 outbred albino rats of both sexes for 1 day. The results obtained indicate active reaction of mesenterial MC on the CMF effect. Their activity is cyclical. High lability of the cellular system was demonstrated. Sexual peculiarities of the reactivity on different stages of CMF action also exist. Mesenterial MC reaction forms the complex of reactions of nonspecific adaptation to light irritants. Mesenterial MC response occurs stagely: orientation, training and relative training. The latter provides change of the tissue homeostasis on a qualitatively new level. Increase of passive and active resistance occurs simultaneously in training phase. This confirms the possibility of use of the CMF of low energies in complex of therapeutic treatment.

Animals↗
PubMed1996

Increased hyaluronan at sites of attachment to mesentery by CD44-positive mouse ovarian and breast tumor cells.

The mouse ovarian ascites tumor, MOT, and mammary ascites tumor, TA3/St, served as models to follow changes in hyaluronan levels during tumor growth, attachment, and invasion. Subsequent to introduction of tumor cells into the peritoneal cavity, hyaluronan accumulated intraperitoneally and at the initial sites of attachment of tumor cells and cell clumps to the mesenteric surface; the latter co-localized with sites of fibrin deposition as reported earlier. Subsequently, high levels of hyaluronan accumulated throughout the interior of the mesentery. Because neither tumor cell line synthesized substantial amounts of hyaluronan in culture, the large accumulations observed in the mesenteries and ascites fluid of tumor-bearing animals most likely resulted from increased synthesis and secretion by peritoneal-lining mesothelial cells and/or fibroblasts in response to stimulation by the tumor cells or their products. TA3/St tumor cells were universally positive for the hyaluronan receptor, CD44, whereas approximately 90% of MOT tumor cells were CD44-negative. However, the great majority of MOT or TA3/St cells that initially attached to the mesentery were strongly CD44 positive. We propose that hyaluronan-rich matrix is involved in tumor cell attachment to the mesentery possibly via interaction with tumor cell surface CD44.

Animals↗
PubMed1998

Effect of flow on hydraulic conductivity and reflection coefficient of rabbit mesentery.

OBJECTIVE: To measure the hydraulic conductivity and reflection coefficient for albumin, as defined by the Starling equation, in rabbit mesentery. METHODS: A section of rabbit mesentery was fixed between two chambers filled with lactated Ringer solution. Flow (Q) of Ringer solution was measured across the mesentery at driving pressures (delta P) between 1 and 6 cm H2O. Hydraulic conductivity was proportional to the slope of the Q-delta P curve. At constant delta P (approximately -2, -4, or -6 cm H2O), flow was measured at three different albumin concentration differences (0.5, 1, and 1.5 g/dl). Unstirred layer effects were minimized by magnetic stirrers. Reflection coefficient was the negative of the slope of the Q-delta pi curve divided by the slope of the Q-delta P curve, where delta pi was the albumin osmotic pressure difference. Hydraulic conductivity was measured before and after testicular hyaluronidase was added to the Ringer solution. RESULTS: There was no significant difference in conductivity per unit area (Lp) for the three different driving pressures. Hyaluronidase increased hydraulic conductivity significantly (p < 0.01) by 72 +/- 56%, indicating that hyaluronan and other glycosaminoglycans contributed to tissue fluid resistance. Reflection coefficient (sigma) increased from 0.02 to 0.14 as flow increased eightfold. CONCLUSIONS: The results suggest that the mesentery tissue provides little restriction to the passage of albumin. The increase in conductivity in the presence of hyaluronidase indicates that tissue hyaluronan and other glycosaminoglycans provide fluid resistance to bulk flow.

Albumins↗
PubMed1987

Arterial supply to the pig intestine: an unusual pattern in the mesentery.

The arrangement of arteries in the mesentery in pigs was studied with latex casts and light microscopy. Arterial arcades, which are characteristic of the mesentery in man and other species, are absent. Instead, a narrow band of numerous, anastomosing arteries gives rise to up to about 500 bundles of arteries and accompanying veins, which radiate out in the mesentery. Each bundle contains up to 30 arteries, but these recombine as they approach the jejunum, and form 1-4 arteriae rectae. The significance of the very large number of small arteries in the mesentery is not known, but they may play a role in the control of blood pressure in the intestinal wall, or as sites of countercurrent exchange.

Animals↗
PubMed2002

Primitive neuroectodermal tumor of the transverse colonic mesentery defined by the presence of EWS-FLI1 chimeric mRNA in a Japanese woman.

We report a case of primitive neuroectodermal tumor (PNET) arising in the transverse colonic mesentery. A 24-year-old Japanese woman was admitted to Kagoshima City Hospital with complaints of abdominal pain and sensations of abdominal fullness of 5 months' duration. On palpation, a mass the size of an infant's head was noted in the right flank. Abdominal computed tomography (CT) and ultrasonography showed a huge mass that consisted of multiple cystic components. On arteriography, a slight tumor stain appeared, with stretched and displaced tributaries of the right colic and middle colic arteries. Barium swallow examination demonstrated that the ascending colon was shifted to the right and small intestine to the left. We performed an en-bloc resection of the tumor in the transverse colonic mesentery, including the ascending colon, proximal jejunum (20 cm in length), and greater omentum. The resected tumor was 12 x 10 x 7 cm in size, 590g in weight, elastic soft in consistency, and multicystic. Histologically, the specimens showed a sheet-like proliferation of spindle-to-polygonal cells, and focally, the tumor formed rosette structures. Immunohistochemically, the tumor cells were positive for neuron-specific enolase (NSE) and mic-2. EWS-FLI1 chimeric mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Based on the above findings, we finally diagnosed the tumor as PNET of the colonic mesentery. There has been no recurrence for 20 months after operation. PNET arising in the mesentery is very rare, and we distinguished PNET from other tumors by immunohistochemical examination and by demonstration of the presence of EWS-FLI1 chimeric mRNA in the tumor.

Adult↗
PubMed1992

Phalloidin prevents leukocyte emigration induced by proinflammatory stimuli in rat mesentery.

The objective of this study was to determine whether phalloidin, a potent microfilament stabilizer, can modify inflammatory mediator-induced leukocyte adhesion and extravasation in postcapillary venules of the rat mesentery. To address this issue, the rat mesentery was prepared for in vivo microscopic observation. Venules with initial diameters ranging between 25 and 35 microns were selected for study. Erythrocyte velocity, vessel diameter, leukocyte rolling velocity, and the number of adherent (stationary for 30 s) and emigrated leukocytes were initially determined during superfusion of the mesentery with phosphate-buffered saline. After these variables were recorded during the control period, either 100 nM platelet-activating factor (PAF), 20 nM leukotriene B4 (LTB4), or 1 microM N-formyl-methionyl-leucyl-phenylalanine (FMLP) was added to the superfusate. Repeat measurements were obtained between 50 and 60 min after initial exposure to the inflammatory mediator. In some experiments, rats were given phalloidin (25 or 500 micrograms/kg iv) 30 min before superfusion with the inflammatory mediators. Superfusion of the mesentery with either PAF, LTB4, or FMLP enhanced leukocyte adherence and emigration and reduced leukocyte rolling velocity. Pretreatment with the low dose of phalloidin effectively prevented leukocyte emigration but had no effect on the increased leukocyte adherence elicited by the three inflammatory mediators. However, when administered at the higher dose, phalloidin prevented both leukocyte adherence and emigration. Neither dose of phalloidin altered the upregulation of neutrophil membrane CD11/CD18 glycoprotein adherence complex induced by PAF or LTB4. These results are consistent with the concept that PAF, LTB4, and FMLP increase leukocyte extravasation by a process that may involve alterations in the endothelial cell cytoskeleton.

Animals↗
PubMed1982

Microcirculation of left atrial muscle, cerebral cortex and mesentery of the cat. A comparative analysis.

By means of transillumination (microtransilluminator and light pipe), comparative analyses were carried out on geometry, topography, and morphometry of microcirculation in the cerebral cortex, left atrial muscle, and mesentery of the cat using computer analysis. In addition, specific types of capillary distribution (concurrent, countercurrent, and asymmetric distribution) in these three organs were ascertained from images visualized on films. These parameters were related to their role in tissue oxygen supply. It was found that mean capillary diameter, mean intercapillary distance, total capillary length, and total capillary surface area differed significantly among the three organs. Differences in mean capillary tortuosity between cerebral and left atrial muscle and between left atrial muscle and mesentery also were significant. Mean capillary tortuosity in mesentery and cerebral cortex was of equal magnitude. In the cerebral cortex, a high degree of tortuosity and asymmetric capillary distribution favor tissue oxygenation. A similar situation exists in left atrial muscle, although some concurrent and countercurrent distribution could be detected. In the mesentery, the combination of high capillary tortuosity and concurrent capillary arrangement is unfavorable for tissue oxygenation.

Animals↗
PubMed2002

Bacteroides fragilis bacteremia associated with portal vein and superior mesentery vein thrombosis secondary to antithrombin III and protein C deficiency: a case report.

Hypercoagulability is one of the causes of portal vein and superior mesentery vein thrombosis. We report a case of Bacteroides fragilis bacteremia associated with portal vein and superior mesentery vein thrombosis secondary to antithrombin III and protein C deficiency. The patient presented with high fever for more than 3 weeks. Abdominal sonography revealed a liver cyst of 1.7 cm in diameter over segment 4 and a renal stone of 0.7 cm in size over the lower portion of the right kidney but no evidence of hydronephrosis. Elevation of liver enzymes was also noted. Intermittent fever was noted despite treatment with ceftriaxone and doxycycline. On Day 15 of hospitalization, blood culture revealed B. fragilis, which prompted further investigation of the source of intraabdominal and pelvic infection. Abdominal computed tomography revealed portal vein and superior mesentery vein thrombosis. Endoscopic studies of the gastrointestinal tract showed no tumor or diverticulum. Study of coagulation factors disclosed deficiency of antithrombin III and protein C. Clinicians should remain aware of the need to promptly search for a portal or mesentery vein thrombosis in cases of Bacteroides bacteremia of unknown origin.

Adult↗
PubMed1991

Arteriolar and venular reactivity to superfusate pO2 in tissues with different metabolic capacity. A study in skeletal muscle and mesentery of the rat.

In skeletal muscle (extensor hallucis proprius) and mesentery of anesthetised (pentobarbital 30 mg/kg) female rats (200 g) we have compared reactivity to O2 of arterioles and venules with their response to a vasoconstrictor (epinephrine 5.5 x 10(-7) M) and a vasodilator (adenosine 10(-4) M). Muscle arterioles fully constricted with O2 and epinephrine and dilated with adenosine (22%). Muscle venules did not respond to changes in superfusate pO2, constricted 18% with epinephrine and dilated 10% with adenosine. In the mesentery changes in superfusate pO2 had no effect on diameters of arterioles or venules but epinephrine fully constricted arterioles and constricted venules by 19%, while adenosine dilated arterioles (6%) but not venules. When we set arteriolar and venular diameters during adenosine superfusion at 100%, muscle arterioles appeared to operate at 63% and mesenterial arterioles at 84% of maximal diameter at normal tissue pO2. For venules these percentages were 91 and 97%, respectively. Arterioles and venules in muscle thus have higher tone and muscle arterioles are greatly sensitive to changes in tissue pO2 while in our preparation mesenterial arterioles are not.

Adenosine↗
PubMed1998

Vascular permeability factor/vascular endothelial growth factor-mediated signaling in mouse mesentery vascular endothelium.

Vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) is a multifunctional cytokine and growth factor that has important roles in both pathological and physiological angiogenesis. VPF/VEGF induces vascular hyperpermeability, cell division, and other activities by interacting with two specific receptor tyrosine kinases, KDR/Flk-1 and Flt-1, that are selectively expressed on vascular endothelium. The signaling cascade that follows VPF/VEGF interaction with cultured endothelium is only partially understood but is known to result in increased intracellular calcium, activation of protein kinase C, and tyrosine phosphorylations of both receptors, phospholipase C-gamma (PLC-gamma) and phosphatidylinositol 3'-kinase. For many reasons, signaling events elicited in cultured endothelium may not mimic mediator effects on intact normal or tumor-induced microvessels in vivo. Therefore, we developed a system that would allow measurement of VPF/VEGF-induced signaling on intact microvessels. We used mouse mesentery, a tissue whose numerous microvessels are highly responsive to VPF/VEGF and that we found to express Flk-1 and Flt-1 selectively. At intervals after injecting VPF/VEGF i.p., mesenteries were harvested, extracted, and immunoprecipitated. Immunoblots confirmed that VPF/VEGF induced tyrosine phosphorylation of several proteins in mesenteric microvessels as in cultured endothelium: Flk-1; PLC-gamma; and mitogen-activated protein kinase. Similar phosphorylations were observed when mesentery was exposed to VPF/VEGF in vitro, or when mesenteries were harvested from mice bearing the mouse ovarian tumor ascites tumor, which itself secretes abundant VPF/VEGF. Other experiments further elucidated the VPF/VEGF signaling pathway, demonstrating phosphorylation of both PYK2 and focal adhesion kinase, activation of c-jun-NH2-kinase with phosphorylation of c-Jun, and an association between Flk-1 and PLC-gamma. In addition, we demonstrated translocation of mitogen-activated protein kinase to the cell nucleus in cultured endothelium. Taken together, these experiments describe a new model system with the potential for investigating signaling events in response to diverse mediators on intact microvessels in vivo and have further elucidated the VPF/VEGF signaling cascade.

Animals↗