Wall Digestion Research Articles

Localisation digestive exceptionnelle des dépôts cristallins dans l’hyperoxalurie primitive

We report 3 cases of primary oxalosis with nephrocalcinosis and severe renal failure. Extrarenal involvement was noted in bones in 3 cases, the heart in 2 cases, the central nervous system in 2 cases, the skin in 1 case and the eye in 1 case. The 3 patients presented with acute digestive disorders. Ultrasonography and CT scans showed digestive wall calcifications in addition to the classic appearance of primary oxalosis such as nephrocalcinosis or bone involvement. Primary hyperoxaluria is characterized by a calcium deposit in different tissues, mainly in kidneys. Digestive wall involvement has never been reported in the literature. Primary oxaluria should be considered in the presence of such a deposit in the gut wall.

Current topics in pancreato-biliary endotherapy: what can we do?

Endotherapy is progressing steadily, especially for various pancreato-biliary diseases. This article introduced new procedures and devices, and revealed improvement of treatment outcomes. Biliary covered metallic stent (CMS) has developed, and the indication of CMS placement is changing because of its removability. CMS is effective not only for unresectable biliary malignancies but also for resectable tumors, benign biliary strictures, and benign pancreatic strictures. Drug-eluting CMS can be used as anti-tumor agents. Interventional endoscopic ultrasonography (EUS) has shifted the treatment paradigm because it is possible to approach lesions through the digestive tract wall. The diagnosis and treatment of pancreatic cancer using interventional EUS technique are effective, feasible, and promising. Recently, trans-gastric necrosectomy for an infected pseudocyst was reported as an alternative treatment to surgery. Double- and single-balloon enteroscopy will be performed more frequently to treat the pancreato-biliary disorders in the patients with altered anatomy. Endoscopic papillary large balloon dilation (EPLBD), new procedure to the papilla, can treat large bile duct stones effectively without lithotripsy. This paper introduces current developments in endotherapy to surgeons. These procedures are of very great interest because they alter the treatment algorithms for many pancreato-biliary diseases.

Rectite neutropénique post-amoxicilline chez un patient immunocompétent : à propos d’un cas

We report a 38-year-old immunocompetent patient who presented with a neutropenic rectitis after a treatment by amoxicillin for nasopharyngitis. Neutropenic colitis is a digestive wall inflammation, preferentially localized in the ileo-caecal area and the right colon, which leads to necrosis and sepsis, and usually occurs in neutropenic patients treated by chemotherapy with an incidence of 6%. It is a serious and often lethal disease. The treatment is supportive, and surgery is limited to the occurrence of complications (perforation, bleeding). Neutropenic colitis occurring in a rectal location after antibiotic therapy in an immunocompetent patient has been rarely described.

NADPH-diaphorase activity in the digestive system of gastropod molluscs Achatina fulica and Littorina littorea

Localization and peculiarities of NO-ergic elements were studied for he first time throughout the entire length of digestive tract of the marine gastropod mollusc Achatina fulica (Prosobranchia) and the terrestrial molusc Littorina littorea (Pulmonata) by using histochemical method of detection of NADPH-diaphorase (NADPHd). NO-ergic cells and fibers were revealed in all parts of the mollusc digestive tract beginning from pharynx. An intensive NADPHd activity was found in many intraepithelial cells of the open type and in their processes in intra- and subepithelial nerve plexuses, single subepithelial neurons, granular connective tissue cells, and numerous nerve fibers among muscle elements of he digestive tract wall as well as in nerves innervating the tract. NADPHd was also present in receptor cells of he oral area and in the central A. fulica ganglia participating in innervation of the digestive tract. The digestive tract NO-ergic system ofA. fulica has a more complex organization that that of L. littorea. In the A. fulica pharynx, stomach, and midgut, directly beneath epithelium, there is revealed a complex system of glomerular structures formed by thin NADPHd-positive nerve fibers coming from the side of epithelium. More superficially under the main groups of muscle elements, small agglomerations of NADPHd-positive neurons are seen, which could be considered as primitive, non-formed microganglia. Peculiarities of distribution and a possible functional role of NO-ergic elements in the digestive tract of molluscs are discussed as compared with other invertebrate and vertebrate animals.

Portuguese Society of Digestive Endoscopy: recommendations for endoscopic mucosal resection

Endoscopic mucosectomy or mucosal resection (EMR) is the resection through an endoscopic procedure of a piece of digestive wall including mucosal layer, muscularis mucosae and partially or completely the submucosal layer.

Cystic dystrophy in gastric heterotopic pancreas complicated by intracystic hemorrhage and fistulisation in the stomach – a pediatric case

Cystic dystrophy of the digestive wall, a rare but well-known complication of heterotopic pancreas when it is located in the duodenum, has been mainly described in adult series. Cystic dystrophy of the heterotopic pancreas within the gastric wall has been reported in only six adult cases. To our knowledge, no pediatric case has been described. We report a 15-year-old boy surgically treated for cystic dystrophy located in the antrum, complicated by an intracystic hemorrhage and fistulisation into the stomach. The diagnosis of heterotopic pancreas must be considered in case of submucosal cystic-gastric lesions, even in pediatric cases. Although the surgical approach is not systematic, it is recommended when cystic dystrophy is symptomatic (e.g., occlusion or hemorrhage).

Acetylcholinesterase, catalase and glutathione S-transferase activity in beet armyworm (Spodoptera exigua) exposed to nickel and/or diazinon

The effect of single and combined action of nickel and pesticide (diazinon) on enzymes activity (glutathione S-transferase, catalase and acetylcholinesterase) in the digestive tract, body wall and fat body as well as basic growth parameters (life span and body mass) of Spodoptera exigua were investigated under laboratory conditions. The experiment was carried out on two nickel treated groups [300 (NiI) and 900 (NiII) mg Ni kg(-1) dry weight of the culture medium] and a control group. The results showed that mortality of caterpillars in NiII group was higher (51.1%) when compare with the controls. The body mass of the caterpillars in the NiI group was higher by 20% than in the control group, and the body mass of the pupae in the NiII group was lower by 22% than in the control group. Exposure to nickel influenced AChE, GST and catalase activity in the body wall (increase up to 66%) and GI tract, while in the fat body the above-mentioned activity remained unchanged. The pesticide application caused a strong, about 70% reduction in AChE activity in GI tract, while in case of GST activity pesticide treatment resulted in multidirectional response depending on the organ. Nickel pre-treatment affects the susceptibility to pesticide, which is manifested in a lower activity of GST and catalase in the fat body (from 26 to 36%), when compare with the other experimental groups.

Une utilisation peu usuelle mais efficace du plasma d’argon : la section des prothèses métalliques expansives

Migration, distal malposition or fracture of self-expanding metallic biliary or esophageal stents rarely occur but may lead to stent dysfunction, mucosal trauma secondary to impaction or friction on the digestive wall. We report our experience of using argon plasma to endoscopically cut three metallic biliary and esophageal self-expanding stents to restore permeability or to treat impaction of the stent after migration, malposition or fracture.

Clinical usefulness of a treatment algorithm for pancreatic pseudocysts

Endoscopic procedures have become a first-line approach to the treatment of pancreatic pseudocysts. Our purpose was to determine the results of a therapeutic algorithm including EUS-assisted drainage, transpapillary drainage, and conventional endoscopic drainage in terms of (1) feasibility and efficacy of the endoscopic procedure and (2) morbidity. Prospective study with a treatment algorithm drawn up before the endoscopic procedure, including either conventional endoscopic transmural drainage (CTMD), conventional transpapillary drainage (CTPD), or EUS-guided transmural drainage (EUS-GTD). A total of 50 patients, including 15 women and 35 men with a mean age of 51 years, were included in this prospective study. The mean size of the pseudocysts was 8.2 cm (range 3-12 cm). A total of 29 pseudocysts did not bulge into the digestive wall (58%); 24 (48%) neither bulged nor communicated with the pancreatic duct. EUS-GTD was performed on 28 patients (56%), CTMD on 13 patients (26%), and CTPD on 8 patients (16%), and endoscopic procedures failed in 1 patient. Technical feasibility was 98% (49/50), and clinical success was achieved in 90% of the cases and disappearance of the pseudocysts in 96% of the cases without significant differences among the 3 groups. The morbidity rate was 18% (9 cases). Five superinfections occurred in the EUS-GTD group and 1 in the CTMD group. One death occurred from late bleeding in the CTMD group. Randomization of patients in this prospective study was not possible because of the different characteristics of the pseudocysts. With this algorithm, clinical success was achieved in 45 (90%) of the cases and disappearance of the pseudocysts in 48 (96%) of the cases with a reasonable morbidity rate. In half of the cases, EUS is required for treating pancreatic pseudocyst.

High and typical 18F-FDG bowel uptake in patients treated with metformin

This prospective and bi-centric study was conducted in order to determine the impact of antidiabetic treatments (AD) on (18)F-FDG bowel uptake in type 2 diabetic patients. Fifty-five patients with previously diagnosed and treated type 2 diabetes mellitus (group 1) were divided in two subgroups: AD treatment including metformin (n=32; group 1a) and AD treatment excluding metformin (n=23; group 1b). The 95 patients without diabetes mellitus made up controls (group 2). (18)F-FDG uptake in small intestine and colon was visually graded and semi-quantitatively measured using the maximum standardized uptake value. (18)F-FDG bowel uptake was significantly increased in AD patients (group 1) as compared to controls (group 2) (p<0.001). Bowel uptake was significantly higher in AD patients including metformin (group 1a) as compared to AD patients excluding metformin (group 1b) (p<0.01), whose bowel uptake was not significantly different from controls (group 2). A metformin treatment was predictive of an increased bowel uptake in the small intestine (odds ratio OR=16.9, p<0.0001) and in the colon (OR=95.3, p<0.0001), independently of the other factors considered in the multivariate analysis. Bowel uptake pattern in the patients treated with metformin was typically intense, diffuse and continuous along the bowel, strongly predominant in the colon, in both the digestive wall and lumen. This study emphasizes that metformin significantly increases (18)F-FDG uptake in colon and, to a lesser extent, in small intestine. It raises the question of stopping metformin treatment before an (18)F-FDG PET/CT scan is performed for intra-abdominal neoplasic lesion assessment.

Location of GbpC protein in Streptococcus mutans UA159

To determine whether the glucan binding protein C (GbpC) with LPXAG motif is anchoring to the cell wall of the Streptococcus mutans UA159 (S. mutans UA159). S. mutans UA159 GbpC C terminal gene segment was amplified by PCR, the gene sequences and the deduced amino acid sequences were analyzed. In order to locate the GbpC of S. mutans, the study isolated the wall fraction following digestion of the cell wall by N-acetylmuramidase, and the GbpC was detected by Western blot analysis. GbpC S. mutans UA159 was located with gold particles. Furthermore, the dextran-dependent aggregation (ddag) phenotype of the S. mutans UA159 under stress condition was observed. S. mutans UA159 GbpC C-terminal LPXTG motif was replaced by LPXAG motif. GbpC was observed in the cell wall component and immunogold experiment showed that the gold particles distributed around the cell wall surface. S. mutans UA159 exhibited ddag+. GbpC with LPXAG motif was still anchoring to the cell wall.

Cell wall ultrastructure of flocculent and non-flocculent Schizosaccharomyces pombe strains. Effect of cell wall hydrolysing enzymes on flocculation and cell wall ultastructure

Scanning and transmission electron microscopic studies revealed the presence of slime-like, amorphous material on the surface of Schizosaccahromyces pombe RIVE 4-2-1 cells, independently, whether they were in flocculated or in non-flocculated state. Close contact of the adjacent cells via the merging outermost cell wall layers was found, however, only in the case of floc formation, which was induced by cultivating the cells in the presence of 6% (v/v) ethanol. Irreversible loss of the flocculation ability of the cells by treatment with proteinases suggests that proteinaceous cell surface molecules as lectins contribute to the cell-to-cell interaction during flocculation. Both proteinase K and pronase treatments removed a distinct outer layer of the cell wall, which indicated that the protein moieties of the phosphogalactomannan outer surface layer has a crucial role in the maintenance of cell wall integrity. In the case of lysing enzyme treatment the removal of the outermost layer was also observed as the first step of the cell wall digestion, while driselase treatment resulted in almost complete digestion of the cell wall.

Aspects of liquor flow in a model chip digester measured using electrical resistance tomography

Digesters for chemical pulping are pressurized reactors that create relative flow between process liquors and wood chips to delignify the wood and produce kraft pulp. As digester size has increased to accommodate higher production rates, operating problems related to liquor flow have increased. These have included accelerated corrosion, decreased countercurrent washing efficiency, problems with chip movement, and increased pulp non-uniformity. In this work, we used an 8-plane electrical resistance tomography (ERT) system to examine a number of important liquor flow issues in a 1/30 scale-model section of a chip digester: the effect of the particle to vessel size ratio on liquor flow uniformity, flow adjacent to the digester walls, and flow exiting the central downcomer.

Single-band mucosectomy for granular cell tumor of the esophagus: safe and easy technique

Mucosectomy involves resection of a digestive wall fragment that frequently removes a part or even all of the submucosal mass. The single-band mucosectomy technique was used to remove a granular cell tumor (GCT) of the esophagus. Only 3% of GCTs, which are relatively uncommon neoplasms, arise in the esophagus. Ultrasonography has allowed for more frequent recognition and better definition of this disease. Until recently, surgical resection of the esophagus has been the only treatment alternative to endoscopic surveillance. Endoscopic techniques such as mucosal resection (EMR), laser, and argon plasma have been proposed as safe and effective alternatives to surgery. However, to date, only a few reports of these endoscopic techniques have been published. This study aimed to evaluate the safety and feasibility of single-band mucosectomy for removing a GCT of the esophagus. Six patients (1 man and 5 women; mean age, 45 years) with a GCT were studied between January 2000 and May 2004. They underwent EMR after endoscopic ultrasonography. The EMR was performed with a diathermic loop after injection of saline solution into the esophageal wall. Only one session was necessary for removal of the tumor from all 6 patients, and no complication was observed. During a mean clinical endoscopic follow-up period of 36 months, no recurrences, scars, or stenoses were observed. These findings show EMR to be a safe and effective technique that allows complete removal of GCTs. Furthermore, this technique provides tissue for a definitive pathologic diagnosis, which laser and argon plasma do not provide. We recommend EMR as the treatment of choice for GCTs after an accurate ultrasonographic evaluation.

Submucosal lesions / extrinsic compression of the upper digestive tract: Is it worthwhile to do endoscopic ultrasonography? Is it so in all cases?

Introduction: finding of localised protrusions in digestive tract wall, submucosal lesions (SL) or extrinsic compression (EC), during ultrasound is not unusual and is one indications for carrying out endoscopic ultrasonography (EUS). However, as this exam is not available in the majority of centres and is not without additional costs and risks, the ration of costs to benefits must be examined.

DEVELOPMENT OF 3-D ANAEROBIC DIGESTER HEAT TRANSFER MODEL FOR COLD WEATHER APPLICATIONS

Anaerobic digester heat losses must be minimized to reduce heating requirements in cold weather applications.Digesters must be designed with proper insulation to control manure temperature through a variety of ambient weatherconditions, but the additional insulation to mitigate cold weather operations must not impede digester economics. Thesedesign aspects are difficult to address for distributed power generation for on-farm anaerobic digestion, as these precludethe use of large-scale systems to reduce capital and operating costs. To investigate and address these issues, a 3-Dmathematical model for simulating heat transfer for anaerobic digesters for cold weather conditions is developed and usedto optimize the various geometrical parameters to achieve an adequate design that limits heat losses. An anaerobic digesterheat transfer model based on computational fluid dynamics (Fluent 6.1) is used to calculate the heat transfer through thecover, floor, and walls of a below-ground lagoon-type digester. Simulated heat transfer results are compared to a 1-Dnumerical model and validated against experimental data using an operating plug-flow anaerobic digester. The 3-Dpredictions have the advantage of avoiding space-averaged boundary conditions and can account for conduction in all threedirections in a digester. Simulated results agree reasonably well with the measurements and the one-dimensional model.Numerical simulations are performed for four digester configurations: (1) rectangular with arched top, (2) rectangular withflat top, (3) cylindrical with flat top, and (4) cylindrical with conical bottom. Sensitivity analysis has demonstrated the heatloss through the digester cover, floor, and walls for different geometrical dimensions. Comparisons of the total heat loss showthat the cylindrical digester with a flat top offers the best geometry to minimize heat losses in cold weather applications, andthat the heat-loss-to-biogas-heat ratio (HLB) is an important parameter for characterizing digester operations in cold climates.

Histology and Histochemistry of the Pharyngeal Cavity and Oesophagus of the Silverside Odontesthes bonariensis (Cuvier and Valenciennes)

The histology of the pharyngeal cavity and oesophagus of the freshwater 'silverside'Odontesthes bonariensis (Cuvier and Valenciennes) and the characteristics of their mucous cells were investigated. The histological characterization of its digestive wall revealed that the mucosa is thrown with longitudinal folds. The epithelium covering the folds was stratified with abundant mucous cells and gustative corpuscles, which are lacking in the oesophagus. The muscularis mucosa was absent. The submucosa presented the compactum stratum. The muscularis was organized in longitudinal and circular layers of muscular striated fibres. The serosa with a flat epithelium was located only in the oesophagus. Using histochemical procedures including methods for localization and characterization of glycoproteins (GPs), no differences were detected between the mucous cells contents of the pharyngeal cavity and those of the oesophagus. The mucous cells showed a weak periodic acid-Schiff (PAS) positive reaction in their content. The reactions for the differential analysis of sialic acids from GPs are feeble for periodic acid-Schiff at low temperature and low pH (PA*S) and KOH/PA*S and strong for periodic acid/borohydride/KOH/PAS (PA/Bh/KOH/PAS) and KOH/PA*/Bh/PAS revealing the scarce presence of C7 or C9 substituted and non-substituted sialic acids and the abundance of C7, C8 substituted sialic acids, O-acyl sugars and neutral sugars respectively. The results suggest that the pharyngeal cavity with the gustative corpuscles would induce the gastric secretion whereas the oesophagus is mainly involved in the transport of the food bolus to the stomach with the aid of abundant secretion of mucus. GPs secreted on the surface of the mucous cells, likely related to environmental conditions, would be involved in the lubrication, protection against abrasion and inhibition of microorganism proliferation.

HEAT TRANSFER MODEL FOR PLUG-FLOW ANAEROBIC DIGESTERS

A comprehensive and fundamental mathematical model that predicts energy requirements to operate a plug-flow anaerobic digester at a specified temperature was developed. This information is supportive to designers as they determine heating requirements and energy use by the digester system. The model accounts for heat loss/gain by the influent and effluent flows, the digester floor, and the top-covering material and walls. In addition, the model accounts for frozen ground surrounding digester walls, thus increasing heat loss through the walls. Solar energy transmitted through the top-covering material is also accounted for in the model. Predicted heat was validated against experimental data, and the results agree reasonably well. The model can be used to estimate energy requirements to operate a plug-flow anaerobic digester on a daily, monthly, or yearly basis. Low energy was required to operate the digester in June through August, the lowest being in July, and more energy was required in November through March. Considerable energy could be saved if the effluent manure heat was used to pre-heat the influent manure.

Improved Technique for Electron Microscope Visualization of Yeast Membrane Structure.

Yeast cells represent a powerful model system in cell biology mainly due to their amenability to genetic manipulations. Increasingly, studies focus on mutant genes resulting in alterations of cellular structures and organelles. To ascertain the phenotypic changes involved, it is often desirable to use the resolving power of electron microscopy. In contrast to higher eukaryotic cells, yeast cells are particularly difficult to preserve mainly due to the presence of a thick cell wall that acts as a barrier against diffusion of fixatives. Although several procedures are targeted to overcome these difficulties, none of them have become established as a standard procedure. As a consequence, electron microscopy is still not used routinely as a tool in yeast cell biology. This prompted us to develop an easy-to-follow protocol for yeast transmission electron microscopy that should be useful in all cases where membrane integrity and organelle morphology is emphasized. One means of making the yeast cytoplasm more attainable to fixation and staining solutions is by enzymatic digestion of the cell wall. Following this approach, we were able to reliably preserve yeast cells and their cellular organelles. Enzymatic treatment with zymolyase 20T to partially remove the yeast cell wall allowed the fixation, preservation, and visualization of the yeast cytoplasm revealing detailed ultrastructure. The advancement of this technique is demonstrated with mitochondria as a model organelle. Our studies on various yeast mutants clearly show the power of the enzymatic digestion technique in visualizing subtle changes of membrane structure and organelle morphology.

Exine ontogeny in Borago officinalis pollen

The primexine matrix is finely granulo-fibrillar up to callose digestion; it becomes distinctly fibrillar at the free microspore stage. The columellae and the tectum are initiated at the middle tetrad stage, the foot layer and the endexine are initiated when the callose wall digestion begins. The columellae are initiated by the deposition of spiral elements around a clear central zone. This hollow aspect of columella disappears when thickening. The foot layer and the endexine are built by the expansion of plasmalemma derived components. The foot layer appears first at the poles, then at the interapertural levels and at last at the apertures while the endexine appears first at the mesoapertures, then it spreads laterally towards the interapertural levels and, at last, at the poles. The gemmae are formed at the free microspore stage over all the tectum. The thickening of the exine takes place essentially during the free microspore stage and continues during the vacuolate microspore one. Apertures are entirely formed before the complete digestion of the callose wall. The ectoapertures are determined by the lacking of the columellae; the sites of the pericolpal cavities and the mesoapertures result from the plasmalemma retraction even before the setting up of the foot layer and the endexine by which they will be delimited respectively afterwards. The endoapertures are determined by the lacking of compact endexine at their level, and merge into a continuous equatorial belt.