In vitro contractile effects of short chain fatty acids in the rat terminal ileum.

Short chain fatty acids (SCFAs), produced in the gut by bacterial fermentation of carbohydrates, change intestinal motility by mechanisms as yet unknown. This study examined the mechanism(s) of action of SCFAs on contractility using isolated rat terminal ileum segments and isolated ileal smooth muscle cells. Strip contractions were recorded under isometric conditions. Intracellular calcium concentration ([Ca2+]i) was measured in single cells loaded with indo-1 penta-acetoxymethyl ester (indo-1 AM). SCFAs (10(-9) to 10(-2) mol/l) induced concentration dependent contractions. The effect was not different among the individual SCFAs. Exogenous acids (namely tartaric and citric acids) caused similar responses as SCFAs, whereas sodium acetate had no effect. The contraction was not blocked by tetrodotoxin, atropine or hexamethonium, showing that it was not mediated through a cholinergic pathway. Moreover, removal of the mucosa or addition of procaine (a local anaesthetic) to the bath did not change the SCFA induced contraction, while verapamil (a calcium-channel antagonist) completely suppressed it. In addition, application of SCFAs to isolated ileal myocytes evoked peaks in [Ca2+]i inhibited by D 600 (a blocker of voltage dependent calcium channels). Taken together, these results suggest that the contractile response stimulated by SCFAs in the rat terminal ileum could result from an acid sensitive calcium dependent myogenic mechanism

Inhibition of acetylcholine induced intestinal motility by interleukin 1 beta in the rat.

BACKGROUND/AIMS: The fact that raised interleukin 1 beta (IL 1 beta) concentrations have been found in the colonic mucosa of rats with experimentally induced colitis and of patients with inflammatory bowel disease indicates that this cytokine may participate in the disturbed intestinal motility seen during inflammatory bowel disease. This study investigated whether IL 1 beta could change the contractility of (a) a longitudinal muscle-myenteric plexus preparation from rat jejunum, ileum, and colon and (b) isolated jejunal smooth muscle cells. METHODS: Isometric mechanical activity of intestinal segments was recorded using a force transducer. Moreover, smooth muscle cell length was measured by image analysis. RESULTS: Although IL 1 beta did not affect jejunal, ileal, and colonic basal contractility, it significantly reduced contractile response to acetylcholine (ACh). This significant inhibition was seen only after 90 or 150 minutes of incubation with IL 1 beta. Pretreatment with cycloheximide blocked IL 1 beta induced inhibition of ACh stimulated jejunal contraction, suggesting that a newly synthesised protein was involved in the effect. NW-nitro-L-arginine (a nitric oxide synthase inhibitor) did not prevent the inhibition induced by IL 1 beta. Blocking neural transmission with tetrodotoxin abolished the IL 1 beta effect on jejunal contractile activity, whereas IL 1 beta had no effect on isolated and dispersed smooth muscle cells. CONCLUSIONS: IL 1 beta inhibits ACh induced intestinal contraction and this inhibitory effect involves protein synthesis but is independent of nitric oxide synthesis. This effect does not involve a myogenic mechanism but is mediated through the myenteric plexus

A Nonlinear Multicriteria Model for Team Effectiveness

The study of team effectiveness has received significant attention in recent years. Team effectiveness is an important subject since teams play an increasingly decisive role on modern organizations. This study is inherently a multicriteria problem as different criteria are typically required to assess team effectiveness. Among the different aspects of interest on the study of team effectiveness one of the utmost importance is to acknowledge, as accurately as possible, the relationships that team resources and team processes establish with team effectiveness. Typically, these relationships are studied using linear models which fail to explain the complexity inherent to group phenomena. In this study we propose a novel approach using radial basis functions to construct a multicriteria nonlinear model to more accurately capture the relationships between the team resources/processes and team effectiveness. By combining principal component analysis, radial basis functions interpolation, and cross-validation for model parameter tuning, we obtained a data fitting method that generated an approximate response with reliable trend predictions between the given data points

Průřez účetních a daňových předpisů ve vybraných zemích EU

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Ekonomická fakulta. Katedra (118) regionální ekonomik

Diabetic gastroparesis: functional/morphologic background, diagnosis, and treatment options.

The regulation of gastrointestinal motility mainly involves the smooth muscle, neural (extrinsic and intrinsic), and hormonal elements, the glial cells, and the interstitial cells of Cajal. An orchestrated function of all these components is required for the appropriate propulsive movement of the food in the gastrointestinal tract. Gastroparesis, a pathological slowing-down of gastric emptying, is a result of the damage to the tissue elements involved in the regulation of motility. Gastroparesis is one of the well-known complications of long-standing diabetes mellitus. Although it is rarely a life-threatening complication, it has a deteriorating effect on the quality of life, leads to unpredictable oscillation of the blood glucose level, and increases the time required for the absorption of food and medicines. This review describes the clinical characteristics of diabetic gastroparesis and summarizes the organic and functional motility abnormalities caused by this complication. Finally, the currently available and potential future therapeutic approaches are summarized