Home About us Contact
|
Home About us Contact | ||
|
|
||
Gut Physiology (gut + physiology)
Selected AbstractsIn vivo analysis of gut function and disease changes in a zebrafish larvae model of inflammatory bowel disease: A feasibility studyINFLAMMATORY BOWEL DISEASES, Issue 7 2010Angeleen Fleming PhD Abstract Background: The aim of this study was to develop a model of inflammatory bowel disease (IBD) in zebrafish larvae, together with a method for the rapid assessment of gut morphology and function in vivo thereby enabling medium-throughput compound screening. Methods: Assays were performed using larval zebrafish from 3,8 days postfertilization (d.p.f.) in 96-well plates. Gut morphology and peristalsis were observed in vivo using fluorescent imaging following ingestion of fluorescent dyes. IBD was induced by addition of 2,4,6-trinitrobenzenesulfonic acid (TNBS) to the medium within the well. Pathology was assessed in vivo using fluorescent imaging and postmortem by histology, immunohistochemistry, and electron microscopy. Therapeutic compounds were evaluated by coadministration with TNBS. Results: A novel method of investigating gut architecture and peristalsis was devised using fluorescent imaging of live zebrafish larvae. Archetypal changes in gut architecture consistent with colitis were observed throughout the gut. Significant changes in goblet cell number and tumor necrosis factor alpha (TNF-,) antibody staining were used to quantify disease severity and rescue. Prednisolone and 5-amino salicylic acid treatment ameliorated the disease changes. Candidate therapeutic compounds (NOS inhibitors, thalidomide, and parthenolide) were assessed and a dissociation was observed between efficacy assessed using a single biochemical measure (TNF-, staining) versus an assessment of the entire disease state. Conclusions: Gut physiology and pathology relevant to human disease state can be rapidly modeled in zebrafish larvae. The model is suitable for medium-throughput chemical screens and is amenable to genetic manipulation, hence offers a powerful novel premammalian adjunct to the study of gastrointestinal disease. (Inflamm Bowel Dis 2010) [source] Genes encoding a group of related small secreted proteins from the gut of Hessian fly larvae [Mayetiola destructor (Say)]INSECT SCIENCE, Issue 5 2006MING-SHUN CHEN Abstract A group of related genes has been isolated and characterized from the gut of Hessian fly larvae [Mayetiola destructor (Say)]. Members in this group appear to encode proteins with secretary signal pep tides at the N-terminals. The mature putative proteins are small, acidic proteins with calculated molecular masses of 14.5 to 15.3 kDa, and isoelectric points from 4.56 to 4.88. Northern blot analysis revealed that these genes are expressed predominantly in the gut of Hessian fly larvae and pupae. Two related genes, G10K1 and G10K2, were isolated as tandem repeats. Both genes contain three exons and two introns. The intron/exon boundaries were conserved in terms of amino acid encoding, suggesting that they arose by gene duplication. The fact that the frequency of this group of clones in a gut cDNA library higher than that of total cDNA clones encoding digestive enzymes suggested that this group of proteins may perform an important function in the gut physiology of this insect. However, the exact functions of these proteins are as yet known since no sequence similarity could be identified between these proteins and any known sequences in public databases using standard methods. [source] Dose effects of the food spice cardamom on aspects of hamster gut physiologyMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 5 2007Ya-Ling Huang Abstract The dose effects of pectic polysaccharide-rich extract from the food spice cardamom (Amomum villosum Lour.) on intestinal environment were investigated. The results showed that pectic polysaccharides and hemicellulose were the major polysaccharides in the cardamom extract. The administration of cardamom extract (0.5 and 1.5 g/100 g diet) effectively (p < 0.05) shortened hamster gastrointestinal transit time by , 58%, increased fecal moisture contents (148,174%), increased SCFA concentrations in hindgut (4.0- to 7.8-fold), decreased the activities of ,- D -glucuronidase (by 71.4,85.7%), ,- D -glucosidase (by 24.3,51.5%), mucinase (by 63.6,72.7%), and urease (by 88.8,90.4%) in feces, and reduced the production of toxic ammonia (by 16.1,64.5%). These findings suggested that the consumption of cardamom extract (at least 0.5 g/100 g diet or 40 mg/day) might exert a favorable effect on improving the gastrointestinal milieu, and also provide a clue to substantiate its traditional therapeutic uses and dosage for intestinal health improvement. [source] Probiotics effects on gastrointestinal function: beyond the gut?NEUROGASTROENTEROLOGY & MOTILITY, Issue 5 2009E. F. Verdu Abstract, The digestive tract works through a complex network of integrative functions. At the level of the gut, this integration occurs between the immune, neuromotor and enteroendocrine systems, coordinating the physical and chemical elements of the intestinal barrier in order to facilitate digestion whilst protecting the gut from unwanted components of the luminal contents. Gastrointestinal function is controlled and coordinated by the central nervous system to ensure effective motility, secretion, absorption and mucosal immunity. It follows that perturbations in this complex network could lead to gut dysfunction and symptom generation. Recently, attention has been focused on the emerging hypothesis that gut luminal content contributes to determine normal GI function and on the therapeutic possibilities arising from modulating its impact on gut physiology and immunity using probiotic bacteria. In this issue of Neurogastroenterology and Motility, two papers explore the effect of specific probiotic bacteria on spinal neuronal activation and in vitro muscle contractility. These papers support the notion that the composition of the intestinal microbiota can influence gut neuro-motor function and enhance our understanding on the mechanisms of action underlying the effects of specific probiotics on gut functional disorders. [source] Immune-mediated alteration in gut physiology and its role in host defence in nematode infectionPARASITE IMMUNOLOGY, Issue 8-9 2004W. I. Khan SUMMARY Activation of the mucosal immune system of the gastrointestinal tract in nematode infection results in altered intestinal physiology, which includes changes in intestinal motility and mucus production. These changes are considered to be under direct immunological control rather than a non-specific consequence of the inflammatory reaction to the infective agent. However, little is known about the immunological basis for the changes in intestinal physiology accompanying nematode infection, or the precise role of these changes in host defence, which remains an important area to explore. In this review we describe the mechanisms by which the immune response to nematode infection influences the changes in two major cells of intestinal physiology, namely smooth muscle and goblet cells, and how these changes in intestinal physiology contribute to the host defence. Data clearly demonstrate that the T helper (Th) 2 type immune response generated by nematode infection plays an important role in the development of infection-induced intestinal muscle hypercontractility and goblet cell hyperplasia and that these immune-mediated changes in intestinal physiology are associated with worm expulsion. These observations strongly suggest that intestinal muscle contractility, goblet cell hyperplasia and worm expulsion share a common immunological basis and may be causally related. These data not only provide insights into host defence in nematode infection in the context of muscle function and goblet cell response, but also have broad implications in elucidating the pathophysiology of a wide range of gastrointestinal disorders associated with altered gut physiology. [source] | |||||||||||||