SEARCH · PubMed Health

Results for “Mesentery”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1979

Potassium permeability of the mesothelium of the frog mesentery.

The mesothelium of the mesentery is a single cell layer described to offer no or every little hindrance to diffusion of small water soluble solutes. We have measured the potassium permeability of the mesothelium of the frog mesentery both in vivo and in vitro. The permeability measured in vivo--using K+--sensitive microelectrodes is 2.4 X 10(-5) cm s-1. In vitro measurements using conventional tracer flux technique on isolated mesentery yields a K+-permeability of 5.7 X 10(-5) cm s-1. These values are 15--30 times smaller than values previously reported from in vitro experiments on rat and rabbit mesentery. Also, the permeability is 12--15 times lower than the K+-permeability of the capillary wall determined on single capillaries in the frog mesentery. In the frog mesentery the mesothelium thus represents an important diffusion barrier compared to the capillary wall. This may be critical in experiments where filtration and reflexion coefficients of the capillaries are determined from measurements of fluid exchange across the capillary wall in response to application of hypertonic solutions on the surface of the mesentery.

Animals↗

PubMed1978

Simultaneous measurement of pressure in the interstitium and the terminal lymphatics of the cat mesentery.

1. Simultaneous measurements of the pressure in terminal lymphatics and interstitial tissue have been made in the exteriorized cat mesentery superfused with either physiological salt solution (Krebs solution) or a water-immiscible fluorocarbon, FC-80. 2. The pressures within individual terminal lymphatics were measured using glass micropipettes attached to a servo pressure-measuring system. Tissue pressures were recorded using saline-filled cotton-wool wicks. 3. Mean pressure recorded in the terminal lymphatics of the Krebs-superfused mesentery were slightly above atmospheric (+0.2 mmHg, n = 45), while those recorded in the FC-80-superfused mesentery were slightly below atmospheric (-0.2 mmHg, n = 46). 4. Tissue pressures were also slightly subatmospheric in the in situ mesentery, and the recently exposed tissue. Continuous superfusion with Krebs solution caused the tissue pressure to rise to atmospheric pressure or above; with FC-80-superfusion the tissue pressure also rose, but never to above atmospheric pressure. 5. Isolated strips of mesentery immersed in Krebs solutions of different concentrations gained weight, but when immersed in FC-80 no change in weight was detected. 6. It was concluded that the interstitial gel of the mesentery is normally unsaturated and that superfusion with Krebs solution leads to tissue oedema. This tendency is less marked in FC-80-superfused preparations. Possible mechanisms for lymph formation and propulsion are discussed.

Animals↗

PubMed1978

The role of various prostaglandins on the correlation between permeability to albumin and cAMP levels in the isolated mesentery.

Prostaglandins (PG) have been shown to raise the level of cyclic AMP (cAMP) in various tissues, and to increase permeability. Whether both events are linked, is at present a matter of speculation. We have investigated the effects of PGE1, E2, A1, A2, F1alpha and F2alpha on an isolated rat mesentery placed in a diffusion cell (surface area : 2 sq.cm). The PGs (5 microgram/ml) increased the passage of (I 125) - Albumin across the mesentery. In other experiments, diks of rat mesentery (surface area : 2 sq.cm) have been incubated in assay tubes, and cAMP levels measured by a binding protein assay. We have observed an excellent correlation between increases in permeability and cAMP levels (r=0.961). In order of increasing potency on both parameters, the PGs may be classified as follows : PGF, PGA and PGE. In the rat mesentery, under the influence of prostaglandins, increases in permeability and in cAMP levels are apparently connected.

Albumins↗

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↗

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↗

PubMed1978

Microvascular pressures and filtration coefficients in the cat mesentery.

1. Filtration coefficient and hydrostatic pressure have been measured in single capillaries and venules in the cat mesentery using a modification of the Landis (1927) single vessel occlusion technique. 2. Venules were found to be filtering fluid, not absorbing it as is often supposed. 3. The mean filtration coefficient in capillaries was 0.018 micrometers . s-1 . mmHg-1 (1.35 X 10(-10)m . s-1 . Pa-1) while that in venules, was 0.027 micrometers . s-1 . mmHg-1 (2.02 X 10(-10)m . s-1 . Pa-1). 4. In both capillaries and venules, filtration coefficient increased with decreasing pressure. 5. The difference between directly measured venular pressure and that calculated from the occlusion data was used to determine the contribution of the interstitium to fluid exchange. In the mesentery superfused with Krebs solution the tissue pressure so determined was found to be zero or subatmospheric initially but became increasingly positive with lengthening exposure of the mesentery.

Animals↗

PubMed1975

Metastatic seeding along the small bowel mesentery. Roentgen features.

1. Intra-abdominal malignant seeding along the small bowel mesentery is roentgenologically identifiable. 2. The anatomic features of the small bowel mesentery and the pathways of flow of ascitic fluid along its peritoneal recesses determine the depostion and growth of seeded metastases. 3. Seeded deposits lodge particularly within the lower recesses of the small bowel mesentery and are reflected by typical changes involving distal ileal loops or the cecum. 4. These are characterized by (a) palisading, arcuate scalloped deflections or gross mass displacement of distal small bowel loops in the right lower quadrant, or (b) extrinsic indentations upon the medial and inferior contours of the cecum. Associated desmoplastic reaction may result in tethering of mucosal folds and angulated fixation of bowel loops.

Adenocarcinoma, Mucinous↗

PubMed1977

[Tumors of the mesentery of the small intestine].

The clinical picture of solid tumors of the intestinal mesentery is varied and depends on the character of growth (benign, malignant), size and anatomical variants of tumor localization in the mesentery. Sometimes, the tumors concerned can induce pseudosyndrome of acute abdomen or inflammation of the adjacent organ secondary involved by tumor. Among complications induced by tumor are as follows: intestinal hemorrhage, peritonitis and acute or partial intestinal obstruction. The roentgenological picture of intestinal mesentery tumors shows some characteristic features. Eight observations of the author are reported.

Adolescent↗

PubMed1978

Structural differences in the mesentery microcirculation between normotensive and spontaneously hypertensive rats.

The mesentery preparation of normotensive rats (NR) (Pcarotis97 +/- 4 mm Hg) and of spontaneously hypertensive rats (SHR) (161 +/- 2 mm Hg) of comparable age (20 +/- 3 weeks) was used to study morphological changes of the microvasculature in established hypertension. The arterioles, classified according to their branching order, had an increased inner diameter in SHR (by 20%). The smooth muscle hypertrophy decreased with smaller vessel size. Pre- and postcapillary vessels were shorter in SHR than in NR by 17 to 35%. The number of these vessels related to the number of the feeding terminal arterioles was found to be reduced by nearly 50% in SHR. The data suggest a lowered arteriolar flow resistance in individual vessels of the hypertensive group concomitant with a gradually disappearing smooth muscle hypertrophy towards the capillary bed. The elevation of the resistance to blood flow in the hypertensive rats is obviously caused by a reduced number of resistance vessels, as seen in the mesentery vascular bed. Similar results were obtained in the true capillaries, which showed greater inner diameters (SHR vs NR:7.2 micron vs 6.4 micron), shortened lengths (141 vs 170 micron) and a reduced number (50 vs 70). Red cell velocity in true capillaries did not differ (0.51 mm/s vs 0.49 mm/s). Arterio-venous shunt vessels were described with an average inner diameter of 11 micron. In SHR these vessels were shorter (424 vs 654 micron) and increased in number. The 'hydraulic hindrance' of AV-shunt vessels and true capillaries together was decreased in SHR; the surface area did not differ between SHR (55.7 . 10(3) micron2) and NR (50.1 . 10(3) micron2) suggesting no major variation in the exchange functions.

Animals↗

PubMed1979

Duodenal and jejunal atresia with agenesis of the dorsal mesentery: "apple peel" small bowel.

Two newborn infants with duodenal and jejunal atresia and agenesis of the dorsal mesentery represent our surgical experience with "apple peel" small bowel or "christmas tree" demormity. The first patient had the typical appearance of this condition. The postoperative course was complicated by hyperbilirubinemia, septicemia, and disseminated intravascular coagulation. The infant is in satisfactory condition 1.5 years after operation. The second patient had agenesis of the dorsal mesentery without spiraling of the bowel around its vascular stalk. The child died after 1 month, with complete absence of extrahepatic bile ducts as seen at a second laparotomy. Neither child had been subjected to gastrostomy.

Duodenal Diseases↗

PubMed1979

[Effect of short-term cerebral ischemia on the microcirculation in the rat mesentery].

The effect of brain ischemia, produced by constriction of the common carotid arteries, on microcirculation in the mesentery was studied in experiments on rats. The spreading and intensity of microcirculatory disturbances were dependent on duration of ischemia and post-ischemia. The state of systemic hemodynamics and microcirculation in the mesentery was compared. Possible mechanisms of the microcirculatory disturbances are discussed.

Animals↗

PubMed1979

[Morphological characteristics of the intramural neural apparatus of the mesentery in neoplasms of the small and large intestines].

The author has studied the nervous elements of the mesentery in various tumors of the large and small intestine. Different structural alterations were found in all the components of the mesentery intramural nervous apparatus: nervous cells, the intracellular plexus, nervous fibres and receptor-structures in all kinds of neoplasms. Various impregnation technics, the Nissle method and routine coloring technics were employed. The variety in pattern of the revealed morphological alterations of the nervous elements and the rate of their involvement are found to be directly dependent on the tumor stage and form, duration of the lesion and the body responsiveness.

Adult↗

PubMedDate not supplied

A gut and mesentery pedicle for bridging lymphatic obstruction: experimental studies.

Experiments have been carried out in the pig. Small bowel and its mesentery are rich in lymphatics. A pedicle of ileum (opened and denuded of its mucosa) and its mesentery has been used to bypass lymphatic obstruction. Diversion of lymphatic drainage from the lower limb into the lymphatics of the bridge has been demonstrated lymphographically in the living animals and also by post mortem injection studies.

Animals↗

PubMed1977

Immune histochemical and electron microscopic observations on so-called non-specific mesenterial lymphadenitis.

Two cases of so-called mesenterial lymphadenitis in childhood were investigated with the immunoperoxidase technique. One more case was studied electron microscopically. All three cases were morphologically identical. In two cases infection with Yersinia enterocolitica was proven serologically. The majority of the lymphoid cells which filled the strongly distended sinuses represented electron microscopically various steps of the lymphocyte transformation. Immune histochemically, the blasts contained large amounts of immunoglobulins. It is suggested that the mitogen and adjuvant activity of bacterial lipopolysaccharides may substantially be involved in the pathogenesis of the characteristic lesion of the mesenterial lymphadenitis.

B-Lymphocytes↗

PubMed1978

Relief of lymph obstruction by use of a bridge of mesentery and ileum.

The background to the use of a bridge of ileum with its associated mesentery in the relief of lymphatic obstruction is described. A case report of the successful use of this method in a 22-year-old patient with lymphoedema praecox is presented. Following experience with further cases, it is suggested that, provided changes in the lymph channels and in the tissues of the affected limb are not irreversibly damaged, effective drainage through small gut lymphatics may be achieved.

Adult↗

PubMed1979

Effect of hemodilution and hemoconcentration on red cell flow velocity in the capillaries of the rat mesentery.

Erythrocyte velocities in capillaries of rat mesentery were measured during systemic normotension and hypotension over a range of hematocrit from 0.31 +/- 0.06 to 0.58 +/- 0.04. Velocity was measured according to the method of Tompkins, Monti and Intaglietta. The hematocrit was varied by isovolemic exchange of blood with 4.5 g% albumin solution (bovine) or packed red cells (Hct. approximately 0.9). Hypotension was induced by hemorrhage to a preselected pressure of about 35 mm Hg. Under normotension red cell velocity stayed almost constant over a range of Hct. from 0.31 +/- 0.07 to 0.58 +/- 0.09. However, during hypotension significant differences were found for control animals (Hct. 0.43 +/- 0.07), hemodiluted animals (Hct. 0.31 +/- 0.06), and hemoconcentrated animals (Hct. 0.58 +/- 0.04). Velocities amounted to 36 +/- 21%, 52 +/- 24%, and 29 +/- 27% respectively, compared to control velocity. These marked differences in red cell velocities are explained by the strong effect of the hematocrit levels on apparent blood viscosities. It is assumed that the post-capillary microvascular bed is the site where the hematocrit level will affect apparent blood viscosity most intensively.

Animals↗

PubMed1977

Isolation and study of functional mast cells from lung and mesentery of the guinea pig.

A method is described for the dissociation of guinea pig lung and mesentery into their component cells. The method comprises incubation of the tissues with the enzyme pronase in Ca++- and Mg++-free saline followed by mechanical dispersion and yields on average 3-8% free mast cells. These cells are morphologically intact and viable. They retain an active sensitization or can be passively sensitized. The levels of cAMP and cGMP in the whole cell suspension respond to catecholamine, histamine or cholinergic stimulation in a way similar to that observed in the corresponding undispersed tissue. Although the separation of guinea pig mast cells from other cells proved to be more difficult than the purification of rat mast cells, an inrichment of greater than 50% has been achieved. The mast cells isolated by this method proliferate in vitro and have been cultured successfully for several months.

Anaphylaxis↗

PubMed1977

Different proliferative responsiveness of fibroblasts and mesothelial cells in the rat mesentery following administration of compound 48/80 at various hours of the day.

The proliferative responsiveness of fibrolasts and mesothelial cells in the mesenterial membrane of normal rats was studied quantitatively after a single i.p. injection of the mast-cell activating and histamine-releasing drug Compound 48/80. To make some allowance for a possible chronobiologic effect of the circadian type on the induced proliferation, the drug was given at 1 a.m., 9 a.m., or 5 p.m., and the animals were examined 16, 24, and 32 h later. The proliferation was estimated by cytophotometric Feulgen DNA measurements in individual fibroblast and mesothelial cell nuclei, and by mitotic frequency counting. The main result was that a larger fraction of fibroblasts than of mesothelial cells was stimulated to proliferation, regardless of the hour of treatment with Compound 48/80. It was further demonstrated that in control animals the fraction of cells of either fibroblastic or mesothelial type present in the S cum G2 cell-cycle phases varied markedly at different hours of the day. Quantitative differences appeared in the induced proliferation with regard to the hour of treatment. The most vigorous proliferative response appeared after administration of the drug at 9 a.m. The fraction of cells in the S cum G2 cell-cycle phases was then increased at 16 h and the fraction of dividing cells at 24 h after treatment, illustrating the promptness of the induced proliferative reaction.

Animals↗