Biliary sphincter motility after neural isolation of the pancreatoduodenal region in conscious dogs

Reduced myoelectric activity in the sphincter of Oddi in a new model of chronic cholangitis in rabbits: an in vivo and in vitro study

BACKGROUND

Chronic cholangitis caused by hepatolithiasis is a common disease in Southeast Asia. Few studies have addressed the effects of chronic cholangitis on cyclic activity of the sphincter of Oddi (SO). In this study, we investigated the changes of myoelectric activity in rabbits with chronic cholangitis in vivo and in vitro.

METHODS

Chronic cholangitis was induced in rabbits by initially introducing three pieces of 2-0 silk suture and sequentially injecting E. coli into the choledochus through the tube in ductus cysticus. In in vivo experiments, myoelectric activity of SO was recorded by a circular electrode through the jejunum stump in conscious animals. In in vitro experiments, the SO was completely isolated and the myoelectric activity was recorded by a circular electrode in a 10-mL organ bath filled with Krebs solution, with or without addition of cholecystokinin-8 (CCK-8), KCl, ionomycin or induction of capacitative calcium entry (CCE).

KEY RESULTS

In comparison with control and non-infected rabbits, the rabbits with chronic cholangitis showed higher levels of alkaline phosphatase and gamma-glutamyltransferase and significant pathological changes including increased inflammatory infiltration and collagen deposition in mucosae or muscular layer. Cyclic myoelectric activity of SO at phases 2 and 3 of migrating motor complex and the excitatory response to CCK-8 were dramatically decreased in animals with chronic cholangitis. Myoelectric activity of SO was also significantly decreased in vitro with or without agonists or with induction of CCE.

CONCLUSIONS & INFERENCES

Myoelectric activity of SO and its response to agonists are decreased in rabbits with chronic cholangitis both in vivo and in vitro.

Gastrointestinal function and quality of life after pylorus-preserving pancreatoduodenectomy

The pylorus-preserving pancreatoduodenectomy (PPPD) has taken the place of the conventional Whipple pancreatoduodenectomy as the standard procedure for various periampullary disease. With recent advances in surgical techniques and improvements in perioperative management, the number of long-term survivors after PPPD is increasing. As a result, surgeons should pay more attention to the patients' postoperative gastrointestinal function, nutrition, and quality of life (QOL). Gastric stasis, which is a frequent complication during the early postoperative period after PPPD, prolongs the hospital stay and impairs the QOL in the intermediate term. Several possible pathogeneses for this gastric stasis have been postulated; however, the precise mechanism remains unclear. The gastric emptying function gradually recovers to the preoperative level by 6 months after PPPD. Pancreatic functions are likely to be maintained for at least 1 year after PPPD; however, in some cases, they tend to gradually deteriorate over time after the operation, depending on the type of pancreatic reconstruction or the preoperative condition of the pancreas. It is important to note that preoperative and postoperative pancreatic exocrine function strongly influence the postoperative outcome regarding such factors as pancreatic fistula, body weight maintenance, nutrition, and the QOL. The QOL, as assessed by questionnaire, normally returns to the preoperative level within 6 months after PPPD, and this correlates with the changes in gastrointestinal function and nutritional status. It still remains an unresolved question, however, whether the Billroth-I PPPD really leads to better long-term nutritional status, but worse early gastric emptying function, than the Billroth-II type of reconstruction.

Manometric and radiographic evaluation of transduodenal sphincteroplasty (papillary dilation) in dogs

PURPOSE: To evaluate, in dogs, the functions of biliary sphincter subjected to dilation hydrostatic balloon by the point of view of the radiographic and manometric alterations. METHODS: Twenty dogs were submitted to laparotomy, duodenotomy, and enlargement of the major duodenal papilla- GA(n=10) - with balloon of 8mm inflated with pressure of 0,5atm, during 2 minutes or to the sham procedure - GB(n=10). The computadorized manometry and the cholangiography were done before and immediately after the initial procedure, one and four weeks after the dilation or the sham. It was calculated from the radiographic images: the mean, standard deviation, absolute and percentual variation of the diameter measures of the papilla. It was measured: the basal pressure in the papilla region, the contraction amplitudes and the choledoc pressure in all observation times (t0, t7 and t28). RESULTS: There was not differences in the diameter measures of the papilla in t0 (GA=5,14 +/- 1,1) (GB=4,64 +/-0,9), as well as in the absolute (0,14 mm) or relative (-2,7%) variations. In the animals of GA the papilla basal pressure measure was found to be smaller in t28 (11,1) than in t0 (18,6) and t7 (16,2). The contraction amplitudes measures were significantly smaller in the postoperatory times (post-t0, t7 and t28) when comparing to the initial time (pre-t0), in the animals of groups A and B. The average pressure values in the choledoc were also smaller in t28 (7,5) than in t0 (17,8) and t7 (12,6) in the animals of GA. CONCLUSION: the function of the major duodenal papilla is partially commited with the dilation, therefore it provoked the basal pressure decrease and compromising of the capacity of sphincter in its cyclical contractions up to the 28 days of observation.

Influences of electroacupuncture at Sibai point on gastric myoelectricity in rats with nerve blockage

AIM: To explore the mechanism of electroacupuncture (EA) at Sibai point in the excitement of gastric myoelectricity.

METHODS: Thirty-two rats were randomly divided into group A, B, C and D. All the rats were electroacupunctured at Sibai Point. Meanwhile, the rats in group A, B, C and D were intraperitoneally injected with normal saline, atropine, hexamethonium and reserpine, respectively. The effects of EA at Sibai point on the gastric myoelectric activities in the rats were observed.

RESULTS: After intraperitoneal injection of atropine and hexamethonium, the average amplitude and ratio of period to time in the phase of high activity of gastric myoelectric slow wave, and the average numbers of the peaks of gastric myoelectric fast wave were significantly decreased (P < 0.01, P < 0.05, P < 0.01), while after intraperitoneal injection of reserpine, the above three parameters were increased (P < 0.01, P > 0.05, P < 0.01). EA at Sibai point partially relieved the inhibitory effect of atropine and hexamethonium on the gastric myoelectric activities in the rats (P < 0.05 or P > 0.05).

CONCLUSION: All the cholinergic, sympathetic and adrenergic nervous systems participate in the regulation and control of EA at Sibai point of Foot-Yangming meridian on gastrointestinal tract.

Duodenal Patch and Sphincterotomy: Modification of an Old Technique to Prevent Graft Pancreatitis

The aim of this study was to preliminarily evaluate the duodenal patch technique combined with open sphincterotomy in terms of prevention of graft pancreatitis. From April 2003 to March 2005, 17 simultaneous pancreas and kidney transplantations were performed using this technique. All recipients are alive with good renal transplant function. Directly after sphincterotomy in 16 pancreatic grafts a good outflow of clear pancreatic juice and a lessening of graft tenseness were observed during surgery. In two transplants an additional sphincterotomy of the Santorini duct sphincter was necessary. In one recipient no pancreatic juice secretion was observed and insulin independence was not obtained. This graft was explanted shortly afterward. In 13 recipients no graft pancreatic or peripancreatic fluid collection requiring intervention was observed. Of the three recipients who developed graft pancreatitis, two required graft pancreatectomy. In conclusion, Sphincterotomy facilitates pancreatic juice outflow by reducing intraoperative graft edema, which could lead to subsequent inflammation. Further studies on the factors inducing graft pancreatitis are necessary to eliminate this severe complication.

The sphincter of Oddi: understanding its control and function

The most common functional disorders of the biliary tract and pancreas are associated with disordered motility of the sphincter of Oddi (SO). The SO is a neuromuscular structure located at the junction of the bile and pancreatic ducts with the duodenum. The primary functions of the SO are to regulate the delivery of bile and pancreatic juice into the duodenum, and to prevent the reflux of duodenal contents into the biliary and pancreatic systems. Disordered motility of the SO leads to the common and painful clinical conditions of SO dysfunction and acute pancreatitis. In order to understand normal SO motility, studies have been performed addressing SO function, control of spontaneous SO activity, responses to bioactive agents, SO innervation, and reflexes with other gastrointestinal organs. These studies have led to the current understanding of how the SO functions and may permit the development of targeted therapy for SO dysfunction and acute pancreatitis. This review summarizes the current knowledge regarding the control and regulation of SO motility, highlighting laboratory based and clinical research performed over the last 5 years.

Quantitative imaging of Na/I symporter transgene expression using positron emission tomography in the living animal

Transgene expression can be measured in living animals by positron emission tomography (PET) using reporter genes associated with radiolabeled substrates or ligands. We examined here whether PET images obtained with a new reporter gene system (sodium/iodide symporter (NIS) and [124I]iodide) could provide quantitative information on gene expression in mice. Mice received various doses of recombinant adenovirus in which the expression of the NIS cDNA was driven by the CMV promoter and subsequently [124I]iodide. Postmortem gamma counting of liver biopsies was correlated to the adenovirus dose and with NIS mRNA concentration. In addition, immunohistochemically NIS-positive cells increased with higher tissue activities. Finally, a linear relationship existed between the postmortem gamma counting in liver tissues and that calculated from images obtained through small animal PET scanning (r = 0.9581), although there was a bias at high and low specific values. This systematic study on 35 animals demonstrates that quantitative information on gene expression can be obtained from PET images using the NIS reporter system. This new methodology of quantitative imaging of gene expression presents the advantage of avoiding extensive radiochemistry, an important step for more disseminated use of this emerging technology. In addition, this work supports further development of the NIS system for noninvasive assessment of gene delivery in preclinical and clinical studies.

Oddi sphincter function after canine auto-pancreas transplantation with bladder drainage

AIM: Several neural and hormonal factors are known to affect motility of sphincter of Oddi (SO). The major roles of SO are to regulate the flow of bile and pancreatic juice into the duodenum and to prevent the reflux of duodenal contents into the biliary and pancreatic duct. After pancreas transplantation, graft SO was denervated and graft pancreatitis might have relations to SO motility. The motility of SO after canine pancreas transplantation with bladder drainage was investigated.

METHODS: Normal canine SO manometry and pancreas graft SO manometry after pancreas transplantation with bladder drainage were performed in seven dogs respectively before and after cholecystokinin (CCK) administration. Data of SO basal pressure, contraction frequency, amplitude and motility index after transplantation and CCK administration were compared with that in controls and before CCK administration.

RESULTS: SO showed regular contractions with a certain basal pressure in control dogs. After transplantation, the graft SO basal pressure and contraction frequency were higher than that in controls, but the amplitude decreased (P < 0.01). There was no great difference in SO motility index. CCK administration could relax normal SO but stimulate graft SO after pancreas transplantation with bladder drainage. After CCK administration, SO basal pressure, frequency and motility index were increased significantly (P < 0.05), in comparison with that before administration. The amplitude remained unchanged (P > 0.05), in comparison with that before CCK administration.

CONCLUSION: After auto-pancreas transplantation with bladder drainage, canine SO motility was inhibited. Basal pressure and frequency increased but amplitude decreased. CCK administration after transplantation had an inhibitory effect on canine SO instead of a relaxation effect observed in normal canine SO. This will increase the resistance of SO to the pancreatic juice flow and induce pancreatic juice stagnation and can not prevent reflux of urine and duodenal contents when the bladder pressure is increased to a certain extent, which may cause graft pancreatitis.

Prospective evaluation of droperidol on sphincter of Oddi motility

BACKGROUND

Droperidol increasingly is used as an effective adjunct for conscious sedation during endoscopic procedures. Given the concern for the effects of narcotics and benzodiazepines on sphincter of Oddi motility, and the potential difficulty in sedating patients undergoing sphincter of Oddi manometry, droperidol could be an ideal agent in this setting.

METHODS

Over a 43-month period, consecutive patients undergoing sphincter of Oddi manometry were studied prospectively. Sphincter of Oddi manometry was performed under general anesthesia in all but 10 patients. Standard retrograde pull-through techniques were used to examine the biliary and/or pancreatic sphincter, depending on the indication for sphincter of Oddi manometry. After the initial two pull-throughs, 5 mg of droperidol were given intravenously and measurements were repeated 5 minutes later.

RESULTS

A total of 55 patients were studied (42 women [76%], 13 men; mean age 43 years). The basal biliary sphincter pressures measured in 35 patients before and after droperidol were, respectively, 56 mm Hg and 48 mm Hg (p = 0.02); the basal pancreatic sphincter pressures measured in 22 patients before and after droperidol were, respectively, 92 mm Hg and 67 mm Hg (p = 0.29). By using a definition for sphincter of Oddi dysfunction of a basal pressure greater than 40 mm Hg, droperidol would have resulted in a change in diagnosis in 5 patients undergoing biliary manometry (one misclassified as sphincter of Oddi dysfunction, 4 misclassified as normal), and 6 patients undergoing pancreatic sphincter manometry (5 misclassified as sphincter of Oddi dysfunction, one misclassified as normal) (total 19% of procedures). No complication was associated with droperidol use.

CONCLUSIONS

Droperidol alters basal sphincter pressures, which in some patients was clinically significant and would have resulted in misclassification. Although safe and well tolerated, droperidol appears to have subtle but clinically significant effects on the sphincter of Oddi.