Search tips
Search criteria

Results 1-4 (4)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
author:("tech, Markus")
1.  Gastroduodeno-plasty performed by distal gastric transection.- A new technique for large duodenal defect closure 
Duodenal ulcer lesions can represent a surgical challenge, especially if the duodenal wall is chronically inflamed, the defect exceeds a diameter of 3 cm and the ulceration is located in the second part of the duodenum.
Patient and method
We present the case of a 70-year-old male, who suffered from a 3 x 4 cm duodenal defect caused by duodenal pressure necrosis due to a 12.5 x 5.5 x 5 cm gallstone. Additionally, this stone caused intestinal obstruction (Bouveret’s syndrome) and bleeding with signs of shock. Besides the gallstone extraction, the common bile duct was drained by a T-tube and the duodenal defect closure was performed by a gastroduodeno-plasty and Bilroth II gastroenterostomy. The postoperative phase was uneventful. The reconstructed duodenum was endoscopically accessible and showed no pathological findings on follow-up.
The reconstruction of a large defect (> 3 cm) of the second part of the duodenum is safely feasible by a gastroduodeno-plasty. The critical gastroduodenal anastomosis can be protected by duodenal decompression, achieved by placing a T-tube in the common bile duct.
PMCID: PMC3432014  PMID: 22873823
Duodenal defect; Bouveret’s syndrome; Gastroduodeno-plasty
2.  Endocytosis and Recycling of Tight Junction Proteins in Inflammation 
A critical function of the epithelial lining is to form a barrier that separates luminal contents from the underlying interstitium. This barrier function is primarily regulated by the apical junctional complex (AJC) consisting of tight junctions (TJs) and adherens junctions (AJs) and is compromised under inflammatory conditions. In intestinal epithelial cells, proinflammatory cytokines, for example, interferon-gamma (IFN-γ), induce internalization of TJ proteins by endocytosis. Endocytosed TJ proteins are passed into early and recycling endosomes, suggesting the involvement of recycling of internalized TJ proteins. This review summarizes mechanisms by which TJ proteins under inflammatory conditions are internalized in intestinal epithelial cells and point out comparable mechanism in nonintestinal epithelial cells.
PMCID: PMC2789582  PMID: 20011071
3.  Mechanism of IFN-γ-induced Endocytosis of Tight Junction Proteins: Myosin II-dependent Vacuolarization of the Apical Plasma Membrane 
Molecular Biology of the Cell  2005;16(10):5040-5052.
Disruption of epithelial barrier by proinflammatory cytokines such as IFN-γ represents a major pathophysiological consequence of intestinal inflammation. We have previously shown that IFN-γ increases paracellular permeability in model T84 epithelial cells by inducing endocytosis of tight junction (TJ) proteins occludin, JAM-A, and claudin-1. The present study was designed to dissect mechanisms of IFN-γ-induced endocytosis of epithelial TJ proteins. IFN-γ treatment of T84 cells resulted in internalization of TJ proteins into large actin-coated vacuoles that originated from the apical plasma membrane and resembled the vacuolar apical compartment (VAC) previously observed in epithelial cells that lose cell polarity. The IFN-γ dependent formation of VACs required ATPase activity of a myosin II motor but was not dependent on rapid turnover of F-actin. In addition, activated myosin II was observed to colocalize with VACs after IFN-γ exposure. Pharmacological analyses revealed that formation of VACs and endocytosis of TJ proteins was mediated by Rho-associated kinase (ROCK) but not myosin light chain kinase (MLCK). Furthermore, IFN-γ treatment resulted in activation of Rho GTPase and induced expressional up-regulation of ROCK. These results, for the first time, suggest that IFN-γ induces endocytosis of epithelial TJ proteins via RhoA/ROCK-mediated, myosin II-dependent formation of VACs.
PMCID: PMC1237102  PMID: 16055505
4.  Differential Roles for Actin Polymerization and a Myosin II Motor in Assembly of the Epithelial Apical Junctional Complex 
Molecular Biology of the Cell  2005;16(6):2636-2650.
Differentiation and polarization of epithelial cells depends on the formation of the apical junctional complex (AJC), which is composed of the tight junction (TJ) and the adherens junction (AJ). In this study, we investigated mechanisms of actin reorganization that drive the establishment of AJC. Using a calcium switch model, we observed that formation of the AJC in T84 intestinal epithelial cells began with the assembly of adherens-like junctions followed by the formation of TJs. Early adherens-like junctions and TJs readily incorporated exogenous G-actin and were disassembled by latrunculin B, thus indicating dependence on continuous actin polymerization. Both adherens-like junctions and TJs were enriched in actin-related protein 3 and neuronal Wiskott-Aldrich syndrome protein (N-WASP), and their assembly was prevented by the N-WASP inhibitor wiskostatin. In contrast, the formation of TJs, but not adherens-like junctions, was accompanied by recruitment of myosin II and was blocked by inhibition of myosin II with blebbistatin. In addition, blebbistatin inhibited the ability of epithelial cells to establish a columnar phenotype with proper apico-basal polarity. These findings suggest that actin polymerization directly mediates recruitment and maintenance of AJ/TJ proteins at intercellular contacts, whereas myosin II regulates cell polarization and correct positioning of the AJC within the plasma membrane.
PMCID: PMC1142412  PMID: 15800060

Results 1-4 (4)