Expression and functional study of cholecystokinin-A receptors on the interstitial Cajal-like cells of the guinea pig common bile duct

BACKGROUND Many studies have shown that interstitial Cajal-like cell(ICLC)abnormalities are closely related to a variety of dynamic gastrointestinal disorders.ICLCs are pacemaker cells for gastrointestinal movement and are involved in the transmission of nerve impulses.AIM To elucidate the expression profile and significance of cholecystokinin-A(CCK-A)receptors in ICLCs in the common bile duct(CBD),as well as the role of CCK in regulating CBD motility through CCK-A receptors on CBD ICLCs.METHODS The levels of tyrosine kinase receptor(c-kit)and CCK-A receptors in CBD tissues and isolated CBD cells were quantified using the double immunofluorescence labeling technique.The CCK-mediated enhancement of the movement of CBD muscle strips through CBD ICLCs was observed by a muscle strip contraction test.RESULTS Immunofluorescence showed co-expression of c-kit and CCK-A receptors in the CBD muscularis layer.Observations of isolated CBD cells showed that c-kit was expressed on the surface of ICLCs,the cell body and synapse were colored and polygonal,and some cells presented protrusions and formed networks adjacent to the CBD while others formed filaments at the synaptic terminals of local cells.CCK-A receptors were also expressed on CBD ICLCs.At concentrations ranging from 10^(-6) mol/L to 10^(-10) mol/L,CCK promoted CBD smooth muscle contractility in a dose-dependent manner.In contrast,after ICLC removal,the contractility mediated by CCK in CBD smooth muscle decreased.CONCLUSION CCK-A receptors are highly expressed on CBD ICLCs,and CCK may regulate CBD motility through the CCK-A receptors on ICLCs.

Impact of simethicone on bowel cleansing during colonoscopy in Chinese patients

BACKGROUND Four-liter polyethylene glycol(PEG)solutions are effective for bowel cleansing,but their large volume might hinder patient compliance.Due to the unique features of Asians,4 L PEG might be a suboptimal bowel preparation in predominantly ethnically Asian countries.In view of this,a balance should be achieved between the volume and effectiveness.The ideal bowel cleansing regimen for a colonoscopy has yet to be determined in a Chinese population.AIM To compare the cleansing efficacy of 3 L PEG plus simethicone with 4 L PEG.METHODS A total of 291 patients were randomly allocated to two groups:Group 1(n=145)received 4 L split-dose PEG(4-P);group 2(n=146)received 3 L split-dose PEG plus simethicone(3-PS).Bowel-cleansing efficacy was evaluated by endoscopists using the Boston bowel preparation scale(BBPS)and the bubbles score.RESULTS Although there were no significant differences in the total BBPS score or the adequate rate of bowel preparation between the two groups,the BBPS score of the right-side colon was significantly higher in the 3-SP group(2.37±0.54 vs 2.21±0.78;P=0.04).Moreover,the use of simethicone significantly reduced bubbles in all colon segments(P<0.001).The mean withdrawal time was significantly shorter in the 3-PS group(8.8±3.4 vs 9.6±2.3;P=0.02).Furthermore,significantly more proximal adenomas were detected in the 3-PS group(53.6%vs 45.7%;P=0.03).In addition,the proportions of patients with nausea and bloating were significantly lower in the 3-SP group(P<0.01 for both).More patients in the 3-PS group expressed willingness to repeat the bowel preparation(87.7%vs 76.6%,P=0.01).CONCLUSION Three-liter PEG shows satisfactory bowel cleansing despite the decrease in dosage,and addition of simethicone with better bubble elimination and enhanced patient acceptance offers excellent potential impact on the detection of proximal adenomas in Chinese patients.