scholarly journals Small intestinal MUC2 synthesis in human preterm infants

2009 ◽  
Vol 296 (5) ◽  
pp. G1085-G1090 ◽  
Author(s):  
Maaike W. Schaart ◽  
Adrianus C. J. M. de Bruijn ◽  
Henk Schierbeek ◽  
Dick Tibboel ◽  
Ingrid B. Renes ◽  
...  

Mucin 2 (MUC2) is the structural component of the intestinal protective mucus layer, which contains high amounts of threonine in its peptide backbone. MUC2 synthesis rate might be a potential parameter for intestinal barrier function. In this study, we aimed to determine whether systemic threonine was used for small intestinal MUC2 synthesis and to calculate the MUC2 fractional synthetic rate (FSR) in human preterm infants. Seven preterm infants with an enterostomy following bowel resection for necrotizing enterocolitis received intravenous infusion of [U-13C]threonine to determine incorporation of systemic threonine into secreted MUC2 in intestinal outflow fluid. Small intestinal MUC2 was isolated using cesium chloride gradient ultracentrifugation and gravity gel filtration chromatography. MUC2-containing fractions were identified by SDS-PAGE/periodic acid-Schiff staining and Western blot analysis and were subsequently pooled. Isotopic enrichment of threonine, measured in MUC2 using gas chromatography isotopic ratio mass spectrometry, was used to calculate the FSR of MUC2. Systemically derived threonine was indeed incorporated into small intestinal MUC2. Median FSR of small intestinal MUC2 was 67.2 (44.3–103.9)% per day. Systemic threonine is rapidly incorporated into MUC2 in the small intestine of preterm infants, and thereby MUC2 has a very high synthesis rate.

2015 ◽  
Vol 129 (7) ◽  
pp. 529-531 ◽  
Author(s):  
Neil A. Mabbott

A new study by Man and colleagues provides further insight into the effects of aging on small intestinal barrier function in humans. Here, their findings are briefly summarised and the wider implications discussed.


Author(s):  
Yuxia Chen ◽  
Yining Xie ◽  
Ruqing Zhong ◽  
Hui Han ◽  
Lei Liu ◽  
...  

Abstract The objective of this study was to investigate the effects of xylo-oligosaccharides (XOS) supplementation on growth performance, serum parameters, small intestinal morphology, intestinal mucosal integrity, and immune function in weaned piglets. A total of 240 weaned piglets with an average body weight (BW) of 8.82 ± 0.05 kg (28 d of age) were assigned randomly to 4 dietary treatments in a 28-d trial, including a control diet (CON), 3 diets with XOS supplementation at the concentration of 100, 500 and 1000 mg/kg (XOS100, XOS500, and XOS1000). There were 4 replicates per treatment with 15 pigs per pen. From d 1 to 14, there were no differences (P > 0.05) in average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) during the different treatments. The different doses of XOS showed a quadratic effect on BW on d 28, ADG and G:F d 1-28 of piglets (P < 0.05). From d 15 to 28, ADG of pigs fed the XOS500 diet was higher (P < 0.05) than pigs fed the CON diet. During the overall period (d 1 to 28), pigs fed the XOS500 diet had a higher BW, ADG and G:F than pigs fed the CON diet (P < 0.05). In addition, compared with the CON group, the XOS500 group had significantly higher serum total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD) and catalase (CAT) levels and lower malondialdehyde (MDA) levels on d 14 and 28 (P < 0.05). The serum immunoglobulin G (IgG) concentration in the XOS500 group was also significantly higher compared with the CON group on d 14 and 28 (P <0.05). However, serum immunoglobulin A (IgA) and immunoglobulin M (IgM) were not affected by the dietary treatments. Supplementation of XOS500 to the feed significantly increased the villus height (VH) and villus height to crypt depth ratio (VH:CD) in the jejunum and ileum in comparison with the CON and XOS1000 group. Moreover, the XOS500 group significantly elevated the expression levels of Occludin and zonula occludens protein-1 (ZO-1) in the ileum compared to the CON group. The ileal interleukin (IL)-1β, IL-8 and interferon (IFN)-γ mRNA expression levels in the XOS100 and XOS500 group were markedly lower than in the CON group. In contrast, the ileal IL-10 mRNA expression levels were remarkably higher in the XOS500 than CON group. In conclusion, xylo-oligosaccharides have a beneficial effect on growth performance by improving serum antioxidant defense system, serum IgG, small intestinal structure and intestinal barrier function in weaned piglets.


Tracheal mucin secretion has been measured from a segment of trachea, isolated in situ , in anaesthetized geese by a method that involves radioactive labelling of tracheal mucus glycoproteins (Gallagher et al. 1975). Goose tracheal mucus comes entirely from goblet cells, since the goose trachea does not contain submucosal mucous or serous glands, and this method has been used to investigate the nervous and pharmacological control of the mucin secretion from these epithelial goblet cells. The mucins secreted have been collected, fractionated, and chemically analysed. Intracellular mucin has been examined histochemically, and the results of electron microscopic observations of epithelial cells and nerves are presented. Acetylcholine increased tracheal mucin secretion, and this effect was completely blocked by atropine. Neither α- nor β-stimulant sympathomimetic amines affected tracheal mucin secretion. Stimulation of the peripheral cut ends of the descending oesophageal nerves increased tracheal mucin secretion and the majority of this response, approximately three-quarters, appeared to be cholinergic since this proportion was blocked by atropine. The mediator for the atropine-resistant part of the response is not known, but it appears not to be a β-adrenoreceptor stimulant since the response to nerve stimulation was unaffected by propranolol given at 34 μm intrasegmentally. Other possibilities are discussed. Atropine itself decreased the resting level of tracheal mucin secretion. The local anaesthetic, lignocaine, increased tracheal mucin secretion, while at the same time blocking the responses to acetylcholine and descending oesophageal nerve stimulation. The implications of this are discussed. The electrophoretic, gel filtration and ion-exchange properties of goose tracheal mucins showed that they represented high molecular mass, negatively charged glycoproteins which could be labelled biosynthetically with [ 35 S]sulphate, [ 3 H]- and [ 14 C]glucose. These mucins could be stained with Alcian blue or periodic acid Schiff reagent. The carbohydrate composition was unusual for an epithelial glycoprotein in that fucose was absent and mannose was present in small quantities. The monosaccharides present in larger quantity were galactose, N -acetylglucosamine, N -acetylgalactosamine and sialic acid. Histochemical analysis of tissue sections of gosling tracheas demonstrated that nearly all of the glycoprotein in epithelial goblet cells contained both sialic acid and sulphate residues. Sialated mucin was present also, but to a lesser extent, and many cells contained a mixture of sialated and sulphated mucins. The adult goose trachea had a high proportion of sialated glycoprotein. Electron microscopy showed a range of epithelial cell types and intra-epithelial nerves also. Many of the nerves had neurosecretory vesicles suggestive of motor function and some were near to goblet cells.


1986 ◽  
Vol 32 (11) ◽  
pp. 884-888 ◽  
Author(s):  
Lucila Isabel Barberis ◽  
Alberto Jorge Eraso ◽  
Maria Cristina Pàjaro ◽  
Inès Albesa

Two thiol-activated Klebsiella pneumoniae hemolysins were purified from growth media by means of salt precipitation, gel filtration, ion-exchange chromatography, and polyacrylamide gel electrophoresis. The hemolysins peaks coincided with the protein and glycoprotein peaks as determined by chromatography and electrophoresis, The molecular weights, estimated by gel filtration, were 8400 and 19 000; by sodium dodecyl sulphate–polyacrylamide gel electrophoresis, the values were calculated as 15 500 and 27 000. The electrophoretic bands were best detected by the periodic acid–Schiff method. Reduction of the disulfide linkages did not cause the originally larger molecule to break into 8400 and 19 000 hemolysins. However, trypsin treatment cleaved the 19 000 hemolysin into an active moiety, with an electrophoretic migration similar to the 8400 hemolysin. A naturally occurring proteolytic activity was investigated using pepstatin and antipain. When the trypsin inhibitor was added to the system, the hemolytic activity was detected only in the 19 000 hemolysin and the smaller hemolysin was absent.


1990 ◽  
Vol 68 (10) ◽  
pp. 1218-1221 ◽  
Author(s):  
H. S. Roychowdhury ◽  
M. Kapoor

The heat shock response of Neurospora crassa was investigated. A 80-kilodalton heat shock protein (HSP 80) was purified to near homogeneity from heat-shocked mycelial extracts employing ammonium sulphate fractionation, gel filtration, and ion-exchange and affinity chromatography. It was observed to migrate as a single band on one-dimensional sodium dodecyl sulphate – polyacrylamide gels, with a molecular mass of ~ 83 kilodaltons (kDa). On two-dimensional gels it resolved into four polypeptide species with isoelectric points in the acidic range, which on staining with periodic acid – Schiff method were demonstrated to be glycosylated. In the native state, HSP 80 had a molecular size of ~610 kDa.Key words: Neurospora, heat shock, fast protein liquid chromatography, 80-kilodalton heat shock protein, glycoprotein.


2001 ◽  
Vol 125 (5) ◽  
pp. 677-679 ◽  
Author(s):  
Monica A. Recine ◽  
Maria T. Perez ◽  
Beria Cabello-Inchausti ◽  
Rogerio C. Lilenbaum ◽  
Morton J. Robinson

Abstract A 57-year-old woman presented with intermittent symptoms of intestinal obstruction. Workup provided nondiagnostic radiologic studies. An exploratory laparotomy revealed a segmental dilatation in the proximal ileum, which showed diffuse thickening of the intestinal wall. Microscopic examination of the affected area disclosed a diffuse transmural infiltrate composed of small lymphocytes, mature plasma cells, and lymphoplasmacytoid cells in different stages of maturation associated with extracellular periodic acid-Schiff–positive material. In addition, serum protein electrophoresis showed a monoclonal immunoglobulin M κ paraprotein. Postoperative workup did not demonstrate evidence of systemic involvement. The morphologic features and immunohistochemical and molecular analyses were consistent with lymphoplasmacytoid lymphoma (immunocytoma). We report an unusual case of primary extranodal immunocytoma involving the small intestine and discuss its clinicopathologic features.


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