Anatomic transformation of the lymphatic bed of the small intestine following immunization]

The experimental investigation of the lymphatic bed of the small intestine after immunization was performed in 15 rabbits. Ten rabbits were taken as control. The rabbits were immunized by administration of kidney antigen with the complete Freund adjuvant. The animals were killed on the 7-8th days after two cycles of immunization, three injections in each cycle. The interval between the injections was three days, between the cycles - one month. Polychrome injection of arteries and veins was made. The lymphatic bed was filled with Gerota's mass. The chylus sinuses, lymph capillaries and vessels of experimental animals were found to be dilated 2-6 times as compared with normal. There appear many blind processes on the walls of lymph capillaries and vessels. Intraorganic lymphatic pathways were more dilated as compared with extraorganic. The ileum was found to be more reactive in immunization than other two parts of the small intestine.     

Biochemical and cytochemical characterization of extracellular proteoglycans in the inner circular smooth muscle layer of dog small intestine

Current literature concerning smooth muscle blood vessels has shown versican as the main proteoglycan (PG) component of the matrix. To show whether smooth muscle matrix has the same PG distribution when present in organs, other than the blood vessels, the inner circular smooth muscle layer of the small intestine was obtained by dissection as a highly purified tissue and analyzed by biochemical and cytochemical methods. The smooth muscle layer PGs were extracted from dog small intestine with 4 M guanidine-HCl in the presence of proteinase inhibitors, purified by charge equilibrium, isolated by equilibrium CsCl density gradients, and analyzed in terms of anion exchange, size, and glycosaminoglycan (GAG) distribution. Proteoheparan sulfate itself represented 91.5% of the PGs present in this tissue. The remainder was proteodermatan sulfate. Cytochemical analyses using the cationic dye cuprolinic blue associated with enzymatic treatments with chondroitinases ABC and heparitinase III showed the arrangement and identification of PGs in basal lamina and intramuscular connective tissues. The PGs in the basal lamina were proteoheparan sulfate, and those associated with collagen fibrils in the endomysium and perimysium were rich in dermatan sulfate. In contrast to the blood vessels, inner circular muscle smooth tissue in intestine has, as the main PG, perlecan.     

Morphofunctional transformations of the blood vessels in the transplantation of syngeneic normal tissue and of a tumor

In 360 Fisher rats dynamics of changes in blood vessels, the microcirculatory bed vessels included, have been investigated. An original model of the experiment at implantation of syngenic tissues of the fetus normal intestine and tumorous adenocarcinoma of the small intestine has been used. Specific changes of the blood vessels have been revealed around and in the capsule of the implant, depending on their morphological reorganization. The blood vessels changes can serve as a prognostic sign of possible alterations in the implant structure.     

家鸽小肠绒毛微血管铸型的扫描电镜观察

用扫描电镜观察了ＡＢＳ丁酮溶液灌注的家鸽小肠绒告发同血管构筑情况。家鸽小肠绒毛血管丛由输入沁动脉、毛细血管网和输出小静脉组成,小肠绒毛血管丰富,并相到吻合成单层密集网;办入小动脉既可从肠腺周围血管丛发出,也可直接由粘膜下去一发出,绒毛下部血管表现为微直血管形态,可能部分具有门静脉性质。     

Study of glucose concentrated solution consumption in rats and simulation of glucose distribution along the intestine

Free ingestion of glucose solution (200 or 400 g/l) by Wistar rats, previously starved for 18-20 Hrs, was investigated in two groups of the animals: with intact small intestine (group 1, n = 9), and a shortened small intestine following the Thiry-Wella isolation of its one third proximal part (group 2, n = 9). In the rats of the group 2, the isolated intestinal loops were perfused in chronic experiments with soulutions of different glucose concentrations to estimate a permeability of the pre-epithelial ("unstirred") layer and "true" kinetic constants of glucose active transport. The rate of glusouse ingestion was found to be 1.3-fold as high in the of rats fgroup 1 than in the rats of group 2 (p < 0.01). According to results of mathematical modeling, the rate of glucose ingestion by rats corresponds to glucose concentration in the initial solutions and to the absorbing capacity of the small intestine due to the substrate regulation of gastric emptying. The model predicts that, during free ingestion by rats of 400 g/l (2200 mM) glucose solution, the substrate concentration in the intestinal lumen under steady state conditions hardly exceeds 75 mM. This fact contradicts a recently proposed hypothesis about a facilitated transport mediated by GLUT2 as the main mechanism of glucose absorption in the small intestine under normal conditions.     

Blood vascular system of the sea cucumber,Stichopus moebii

Stichopus moebii, a sea cucumber, has a closed circulatory system which is unique in its degree of development for the phylum Echinodermata. The gross anatomy, histology and fine structure of the system were studied. Blood vessels consist of a coelomic surface of ciliated epithelium, a layer of muscle and nerve cells, followed by connective tissue and luminal lining of endothelium. Basically the blood vascular system consists of two major vessels running parallel to the gut: the dorsal vessel pumps colorless blood via the vessels within the walls of the intestine into the ventral vessel. There are two specialized areas of the circulation: (1) At the upper small intestine 120 to 150 muscular single-chambered hearts pump blood from the dorsal vessel into a series of intestinal plates. (2) At the lower region of the small intestine the vasculature is associated with the left respiratory tree. Blood passing from the dorsal pulmonary vessel can take two routes to the gut, it either passes through myriads of minute respiratory shunt vessels entangled with the respiratory tree or it passes through a unique follicle network consisting of tiny channels periodically dilated into chambers filled with iron deposits, necrotic cells and developing coelomocytes.     

The regulation of phosphate-activated glutaminase activity and glutamine metabolism in the streptozotocin-diabetic rat.

The activity of phosphate-activated glutaminase was increased in the kidney, liver and small intestine of rats made diabetic for 6 days with injection of streptozotocin (75 mg/kg body wt.). Insulin prevented this increase in all three tissues. Treatment with NaHCO3, to correct the acidosis that accompanies diabetes, prevented the increase in renal glutaminase activity, but not that in liver or small intestine. Chemically induced acidosis (NH4Cl solution as drinking water) or alkalosis (NaHCO3 solution as drinking water) increased and decreased, respectively, glutaminase activity in the kidney, but were without significant effect on the activity in liver and small intestine. The increase in glutaminase activity in the small intestine during diabetes was due to an overall increase in the size of this organ, and was only detectable when activity was expressed in terms of whole organ, not mucosal scrapings or isolated enterocytes. Prolonged diabetes (40 days) resulted in an even greater increase in the size and glutaminase activity of the small intestine. Despite this marked increase in capacity for glutamine catabolism, arteriovenous-difference measurements showed a complete suppression of plasma glutamine utilization by the small intestine during diabetes, confirming the report by Brosnan, Man, Hall, Colbourne & Brosnan [(1983) Am. J. Physiol. 235, E261-E265].     

Methods of selection, preparation and evaluation of the viability of small-intestinal fragments suitable for transplantation

In the experiment performed on cats, using histological, histochemical and impregnative techniques it has been stated that choose of the small intestine area, suitable for transplantation should be based on counting straight vessels ramified in it. In order to ensure viability of the small intestine fragment the method of its preliminary treatment is recommended, based on training blood vessels. For estimating viability of the transplant it is possible to ascertain SDG activity in neurons of the intramural nervous ganglia and estimate amount of secreting gobletlike cells in mucous membrane of the small intestine loop.     

Structural changes in the small intestine wall and its lymphatic bed after gastrectomy

Morphologically and histochemically structural changes of the small intestine wall and its lymphatic bed have been studied in 104 dogs after the stomach resection. After the operation an increase in the diameter of the lymphatic capillaries and vessels takes place. Lateral dilatations and protrusions in the capillary walls appear, new anastomoses in all the membranes are formed, they are mostly manifested in the mucous membrane. Histopathological rearrangement in the small intestine wall is demonstrated as edema of the mucous membrane, as plethora of the vessels, as lymphoid infiltration and as changes of the villi forms.     

Isoosmotic transport of fluid across the hamster small intestine in the presence of phlorizin-induced inhibition of sugar transport.

Experiments were performed to investigate whether the fluid transported across the small intestine is isoosmotic with the mucosal solution when the active transport of glucose is partially inhibited. Everted hamster mid small intestine was incubated in one of the following four mucosal solutions: (1) Isotonic control, Krebs-Ringer bicarbonate solution containing 10 mM glucose (KRBSG), (2) Isotonic with phlorizin, KRBSG + 5X10-5 M phlorizin, (3) Hypertonic control, KRBSG + 50 mM mannitol, (4) Hypertonic with phlorizin, KRBSG + 50 MM mannitol + 5x10-5 M phlorizin. The serosal surface of the intestine was not bathed. Results indicate that the transported fluid was always isoosmotic with any of the mucosal solutions used. When the mucosal solution was made hypertonic with mannitol, the concentration of glucose and electrolytes in the absorbate increased, and as a result, the absorbate became hypertonic and isoosmotic with the mucosal solution. The presence of phlorizin either in the isotonic or in the hypertonic mucosal solution decreased the glucose concentration of the absorbate, but the transported fluid became isoosmotic with the mucosal solution due to a higher concentration of Na, K, and their associated anions. Phlorizin caused a decrease in the transmural potential difference. In spite of this, the presence of this glucoside in the mucosal solution increased the transport of sodium in relation to glucose transport. It is suggested that, at the concentrations used, phlorizin inhibits sodium movement through the electrogenic pathway, but increases the transport of this ion through the non-electrogenic route. This increase in neutral sodium transport seems to compensate for the low concentration of glucose in the absorbate, so that the absorbate becomes isoosmotic with the mucosal solution whether the latter is isotonic or hypertonic. It is suggested further that isoosmotic transport of fluid is an inherent property of the small intestine and that there may be an osmoregulatory mechanism in the gut which controls this process.     

Inhibition of NaCl appetite when DOCA-treated rats drink saline

Marked increases in the consumption of concentrated NaCl solution were elicited in rats by daily injection of the synthetic mineralocorticoid, deoxycorticosterone acetate (DOCA). DOCA-treated rats drank different volumes of NaCl solution depending on its concentration (between 0.15 M and 0.50 M), with less consumed (in milliliters) the more concentrated the fluid was. In consequence, total Na(+) intake (in milliequivalents) was roughly similar in all groups. Gastric emptying of Na(+) also diminished as the concentration of the ingested NaCl solution increased, and the delivery of Na(+) to the small intestine was remarkably similar in all groups. Cumulative volume of ingested fluid in the stomach and small intestine was very closely related to intake (in milliliters) of the concentrated NaCl solutions. Systemic plasma Na(+) levels did not increase until after rats stopped consuming concentrated NaCl solution, although they were elevated at the onset of water ingestion. The situation appeared to be different when 0.15 M NaCl was consumed. This isotonic solution emptied and was absorbed relatively rapidly, and DOCA-treated rats drank larger amounts of it throughout a 1-h test period than when they drank concentrated NaCl solutions. Collectively, these findings suggest that saline consumption by DOCA-treated rats may be inhibited by two presystemic factors, one related to the volume of ingested fluid (i.e., distension of the stomach and small intestine) and one related to its concentration (i.e., elevated osmolality of fluid in the small intestine and/or in adjacent visceral tissue).     

猪小肠移植术供肠的灌洗和保存

目的探讨围手术期移植小肠灌注和保存的方法。方法切取猪供肠后,采用100 cm左右高度、略加压法,经移植肠血管以15 mL/min左右灌洗速度持续灌注4℃ 3%羟乙基淀粉注射液、4℃生理盐水保存移植肠。移植前对保存的移植小肠进行组织学检查。结果供肠总灌注时间为50.5±10.6 min;冷缺血时间为80.24±24.62min。组织学检查显示移植肠组织学没有明显改变。移植肠存活良好。结论采取上述方法在短时间内可以提供质量良好的供肠。     

Ultrastructure of catecholamine-containing axons in the intestine of the domestic fowl

Axons in the duodenum, ileum and rectum of the domestic fowl were identified as catecholamine-containing (CA) on the basis of positive reactivity following chromaffin fixation for electron microscopy. CA-axons in association with blood vessels in all regions of the intestine and in non-vascular sites in the small intestine had a 'typical' adrenergic appearance, in that they contained many small granular vesicles (SGV) and variable numbers of large granular vesicles (LGV). In the rectum the non-vascular CA-axon profiles were atypical, in that there were many elongated LGV and few SGV, and the chromaffin reactivity was weak. The nerve profiles in the rectum were dramatically reduced following 6-hydroxydopamine and reserpine treatment and were absent in rectum cultured in the absence of extrinsic ganglia. It was concluded that the profiles, in spite of their low chromaffin reactivity, truely represent CA-axons. The possibility was raised that the atypical morphology and reduced chromaffin reactivity is due to the presence of adrenaline.     

Characteristics of transport of fluoresceinated methotrexate in rat small intestine

The small intestinal damage induced by the methotrexate (MTX) treatment results in malabsorption and diarrhea. The fluoresceinated methotrexate (F-MTX) may possibly be useful to study such effects of MTX on the small intestine. The purpose of this study is to characterize the transport of F-MTX in the small intestine in order to use it as a membrane transport and cellular marker of MTX. The transport of F-MTX in the rat small intestine (jejunum) was examined in the in vitro everted segments of the intestine. The uptake was pH-dependent and showed a maximal effect at pH 6.0, which was the same as the results of MTX previously reported. Further, it was temperature-dependent and was inhibited by metabolic inhibitors, dinitrophenol and sodium azide, and by MTX. The transport kinetics at pH 6.0 in the mucosal solution and at pH 7.4 in the serosal solution was saturable with Km of 0.48 +/- 0.23 microM and Vmax of 0.66 +/- 0.24 pmol/cm/min and in addition, the passive diffusion was observed there. These results suggested that the transport of F-MTX was energy-dependent and was mediated by the same transporter as that of MTX, although, in addition to it, other transport mechanism might contribute to the F-MTX transport. Therefore F-MTX will be of great use to investigate the MTX transport system in the normal and diseased states of small intestine, using various fluorescence techniques like visualization of membrane-associated transport proteins.     

Study of the innervation of blood vessels of the digestive organs by fluorescence microscopy]

The blood vessels of the samll intestine and the gallbladder were shown to possess a great amount of adrenergic nerve fibres which, when penetrating the thickness of the wall of the above organs, become thinner and the distributed between the tissue structures of the organs as the thinnest monoaxonal network. The method of Falck--Hillarp--Krokhina was used. Among the vessel nerves there are perivascular nerves accompanying the vessels along their total legnth, juxtavascular and intramural nervous bundles of the sumpathetic nature detected by the fluorescent-microscopy method. Large arteries are disposed in a considerably thicker network of specifically fluorescing fibres than veins and small arteries.     

The Effect of Exogenous Peroxiredoxin 6 on the State of Mesenteric Vessels and the Small Intestine in Ischemia–Reperfusion Injury

Oxidative stress is the main component of pathogenesis in ischemia–reperfusion injury. The administration of exogenous antioxidants suppresses oxidative stress and may decrease the severity of ischemia–reperfusion injury. The intestine is one of the most sensitive organs to the effect of ischemia–reperfusion. A rat model of a small intestine ischemia–reperfusion injury, based on occlusion of the superior mesenteric artery, was used in this work. Recombinant peroxiredoxin 6, a representative of an ancient family of peroxidases that are able to neutralize a broad range of both organic and inorganic peroxides, was used as an exogenous antioxidant. The intravenous administration of the exogenous peroxiredoxin 6 prior to ischemia–reperfusion minimizes tissue injury and reduces apoptotic cell death in the intestine and the mesenteric vessels. The impact of the exogenous peroxiredoxin 6 upon the NO level elevation in animal blood has been shown to be correlated with the enhanced inducible NO synthase expression. Thus, the use of exogenous peroxiredoxin 6 in ischemia–reperfusion injury of the intestine and the mesenteric vessels promotes normalization of the tissue redox homeostasis, structure protection, and restoration of the microvasculature.     

Occurrence of heparin and multisulfated chondroitins in the rat gastrointestinal tract and effect of fat feeding

Rats were fed glucose solution for 3 days and killed without fasting. Examination of the crude polysaccharides extracted from the gastrointestinal tract by electrophoresis on the micro scale and using critical electrolyte concentration and bacterial enzymes showed three types of sulfated mucopolysaccharides were present. These were identified as heparitins, multisulfated chondroitins, and heparins. The heparin resembled a macromolecular heparin of moderate molecular weight. Following oil feeding, only the heparitins and multisulfated chondroitins were present in the small intestine, and no heparin was found. With fasting for 12 h after glucose feeding, the amount of the heparin fraction in the small intestine was reduced. The results obtained demonstrate the presence of a heparin in the rat small intestine which is responsive to changes in diet.     

Exocoelomic internal hernia: elucidation of Papez's concept.

Two internal herinias of the intestines were found in adult males. One was a large translucent avascular membranous sac contining the small intestine from the duodenojejunal flexure to a point 6 in. proximal to the ileocaecal junction. The other was a peritoneal sac enclosing the small intestine, appendix, caecum and 6 in. of the ascending colon. The mesenteric and colic vessels were normal. Both hernias conformed to PAPEZ's concept of the so-called paraduodenal hernia that the hernial sac is derived from the umbilical coelom. The authors suggest that most of the so-called paraduodenal hernias are derived from the embryonic umbilical peritoneal diverticulum rather than from the peritoneal recesses or mesentery of the colon.     

Sensory neurons of metasympathetic (intramural) ganglia in the guinea pig small intestine

The hypothesis that multiaxonal neurons of the myenteric plexus of the small intestine are sensory neurons, was tested. The rising principle of the issue to sensory information in the metasympathetic ganglions of the small intestine was discovered by microapplication of the salt acid solution. Serotonin (5-hydroxytriptamine) and acetylcholine can participate in forming primary sensory signals in the multiaxonal neurons. Pulsed activity in primary sensory neurons by mucous perfusion of the small intestine by physiological solution with pH 3.5-3.8 was revealed. The enterochromaffin cells of the mucosa and multiaxonal neurons of the submucous and myenteric plexuses take part in reception of the salt acid.     

Lymphatic endothelium expresses PECAM-1

The expression of adhesion molecules on the lymphatic endothelium of human small intestine and submandibular lymph node was studied immunohistochemically with the antibodies for selectin family and Ig superfamily members. In both small intestine and submandibular lymph node, lymphatic endothelium did not express intercellular adhesion molecule-1 and endothelial cell-selectin but expressed platelet-endothelial cell adhesion molecule-1 (PECAM-1). Though lymphatic vessels may not have a positive function in leukocyte rolling and adhesion, lymphatic endothelium may interact with leukocytes, with PECAM-1 playing a role.