Inositol 1,4,5-trisphosphate formation, cytoplasmic calcium dynamics, and α-amylase secretion of pancreatic acini isolated from aged and chronically alcohol-fed rats

Methods. Three-month-old female Wistar rats were fed with 20% alcohol in their drinking fluid over 6–17 mo using an interrupted feeding regimen. At different times, pancreatic acini were isolated by mild collagenase digestion. The concentrations of inositol-1,4,5-trisphosphate (1,4,5-IP3) were determined by a specific radioreceptor assay, before and at different times after stimulation with varying concentrations of CCK-8. CCK-induced dynamics of cytoplasmic calcium ([Ca²⁺]_c) was investigated in acinar cells by confocal laser raster microscopy. Acinar α-amylase (Aml) secretion was measured as enzyme activity in the medium compared to the total activity in the suspension. Results. In 12–13-mo-old rats, the CCK-stimulated 1,4,5-IP₃ formation in acini was found to be decreased compared to young rats (age 4 mo). In rats of the same age fed with ethanol from the age of 3 mo on, 1,4,5-IP₃ concentrations in acini were higher and reached values comparable to those in young rats. Corre-spondingly, the CCK-induced [Ca²⁺]_c dynamics in acini isolated from 9-mo-old rats was impaired compared to that of young rats but normal in aged, chronically alcohol-fed rats. Aml secretion under CCK stimulation, however, which was decreased in aged rats, was additionally impaired after alcohol feeding.     

Inositol 1,4,5-trisphosphate formation, cytoplasmic calcium dynamics, and alpha-amylase secretion of pancreatic acini isolated from aged and chronically alcohol-fed rats.

METHODS: Three-month-old female Wistar rats were fed with 20% alcohol in their drinking fluid over 6-17 mo using an interrupted feeding regimen. At different times, pancreatic acini were isolated by mild collagenase digestion. The concentrations of inositol-1,4,5-trisphosphate (1,4,5-IP3) were determined by a specific radioreceptor assay, before and at different times after stimulation with varying concentrations of CCK-8. CCK-induced dynamics of cytoplasmic calcium ([Ca2+]c) was investigated in acinar cells by confocal laser raster microscopy. Acinar alpha-amylase (Aml) secretion was measured as enzyme activity in the medium compared to the total activity in the suspension. RESULTS: In 12-13-mo-old rats, the CCK-stimulated 1,4,5-IP3 formation in acini was found to be decreased compared to young rats (age 4 mo). In rats of the same age fed with ethanol from the age of 3 mo on, 1,4,5-IP3 concentrations in acini were higher and reached values comparable to those in young rats. Correspondingly, the CCK-induced [Ca2+]c dynamics in acini isolated from 9-mo-old rats was impaired compared to that of young rats but normal in aged, chronically alcohol-fed rats. Aml secretion under CCK stimulation, however, which was decreased in aged rats, was additionally impaired after alcohol feeding. CONCLUSION: Chronic alcohol feeding modifies 1,4,5-IP3 formation, the [Ca2+]c dynamics of, and the Aml secretion of rat pancreatic acini in response to CCK stimulation. Obviously, the age-related impairment of 1,4,5-IP3 formation and [Ca2+]c dynamics is improved. In contrast, the decrease in Aml secretion of acini isolated from aged rats is more pronounced after long-term alcohol-feeding.     

Device-assisted enteroscopy: A review of available techniques and upcoming new technologies

The advent of video capsule endoscopy into clinical routine more than 15 years ago led to a substantial change in the diagnostic approach to patients with suspected small bowel diseases, often indicating a deep enteroscopy procedure for diagnostical confirmation or endoscopic treatment. Device assisted enteroscopy was developed in 2001 and for the first time established a practicable, safe and effective method for evaluation of the small bowel.Currently with double-balloon enteroscopy, single-balloon enteroscopy and spiral enteroscopy three different platforms are available in clinical routine.Summarizing, double-balloon enteroscopy seems to offer the deepest insertion depth to the small bowel going hand in hand with the disadvantage of a longer procedural duration. Manual spiral enteroscopy seems to be a faster procedure but without reaching the depth of the DBE in currently available data. Finally,single-balloon enteroscopy seems to be the least complicated procedure to perform. Despite substantial improvements in the field of direct enteroscopy,even nowadays deep endoscopic access to the small bowel with all available methods is still a complex procedure, cumbersome and time-consuming and requires high endoscopic skills. This review will give an overview of the currently available techniques and will further discuss the role of the upcoming new technology of the motorized spiral enteroscopy(PowerSpiral).