Pylorus

Most animal species are cold-blooded, and their neuronal circuits must maintain function despite environmental temperature fluctuations. The central pattern generating circuits that produce rhythmic motor patterns depend on the orderly activation of circuit neurons. We describe the effects of temperature on the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis. The pyloric rhythm is a triphasic motor pattern in which the Pyloric Dilator (PD), Lateral Pyloric (LP), and Pyloric (PY) neurons fire in a repeating sequence. While the frequency of the pyloric rhythm increased about 4-fold (Q(10) approximately 2.3) as the temperature was shifted from 7 degrees C to 23 degrees C, the phase relationships of the PD, LP, and PY neurons showed almost perfect temperature compensation. The Q(10)'s of the input conductance, synaptic currents, transient outward current (I(A)), and the hyperpolarization-activated inward current (I(h)), all of which help determine the phase of LP neuron activity, ranged from 1.8 to 4. We studied the effects of temperature in >1,000 computational models (with different sets of maximal conductances) of a bursting neuron and the LP neuron. Many bursting models failed to monotonically increase in frequency as temperature increased. Temperature compensation of LP neuron phase was facilitated when model neurons' currents had Q(10)'s close to 2. Together, these data indicate that although diverse sets of maximal conductances may be found in identified neurons across animals, there may be strong evolutionary pressure to restrict the Q(10)'s of the processes that contribute to temperature compensation of neuronal circuits.

ObjectiveGlucagon-like peptide 1 (GLP1) is rapidly inactivated by dipeptidyl peptidase 4 (DPP4), but may interact with vagal neurons at its site of secretion. We investigated the role of vagal innervation for handling of oral and i.v. glucose.Design and methodsTruncally vagotomised subjects (n=16) and matched controls (n=10) underwent 50 g-oral glucose tolerance test (OGTT)±vildagliptin, a DPP4 inhibitor (DPP4i) and isoglycaemic i.v. glucose infusion (IIGI), copying the OGTT without DPP4i.ResultsIsoglycaemia was obtained with 25±2 g glucose in vagotomised subjects and 18±2 g in controls (PConclusionsGIGD is diminished, but the incretin effect is unaffected in vagotomised subjects despite higher GLP1 levels. This, together with the small effect of DPP4i, is compatible with the notion that part of the physiological effects of GLP1 involves vagal transmission.

BackgroundThe aim of this meta-analysis was to compare the long-term survival, mortality, morbidity and the operation-related events in patients with periampullary and pancreatic carcinoma undergoing pylorus-preserving pancreaticoduodenectomy (PPPD) and pylorus-resecting pancreaticoduodenectomy (PRPD).MethodA systematic search of literature databases (Cochrane Library, PubMed, EMBASE and Web of Science) was performed to identify studies. Outcome measures comparing PPPD versus PRPD for periampullary and pancreatic carcinoma were long-term survival, mortality, morbidity (overall morbidity, delayed gastric emptying [DGE], pancreatic fistula, wound infection, postoperative bleeding, biliary leakage, ascites and gastroenterostomy leakage) and operation related events (hospital stays, operating time, intraoperative blood loss and red blood cell transfusions).ResultsEight randomized controlled trials (RCTs) including 622 patients were identified and included in the analysis. Among these patients, it revealed no difference in long-term survival between the PPPD and PRPD groups (HR = 0.23, p = 0.11). There was a lower rate of DGE (RR = 2.35, p = 0.04, 95% CI, 1.06-5.21) with PRPD. Mortality, overall morbidity, pancreatic fistula, wound infection, postoperative bleeding, biliary leakage, ascites and gastroenterostomy leakage were not significantly different between the groups. PPPDs were performed more quickly than PRPDs (WMD = 53.25 minutes, p = 0.01, 95% CI, 12.53-93.97); and there was less estimated intraoperative blood loss (WMD = 365.21 ml, p = 0.006, 95% CI, 102.71-627.71) and fewer red blood cell transfusions (WMD = 0.29 U, p = 0.003, 95% CI, 0.10-0.48) in patients undergoing PPPD. The hospital stays showed no significant difference.ConclusionsPPPD had advantages over PRPD in operating time, intraoperative blood loss and red blood cell transfusions, but had a significantly higher rate of DGE for periampullary and pancreatic carcinoma. PPPD and PRPD had comparable mortality and morbidity including pancreatic fistulas, wound infections, postoperative bleeding, biliary leakage, ascites and gastroenterostomy leakage. Our conclusions were limited by the available data. Further evaluations of high-quality RCTs are needed.

IntroductionDelayed gastric emptying (DGE) due to pyloric dysfunction remains a common postoperative complication after esophagectomy for cancer and can lead to severe secondary complications. As shown in a retrospective study, prophylactic EPBD performed 1 day before surgery can reduce the rate of postoperative DGE by reducing pyloric resistance. The objective of this study is to analyze the effect of prophylactic EPBD on postoperative DGE rates in patients receiving minimally invasive esophagectomy for cancer by gastric pull-up.MethodsThis study is designed as a multicenter randomized controlled trial (RCT) including patients with esophageal cancer or cancer of the gastroesophageal junction (adenocarcinoma and squamous cell carcinoma, with or without neoadjuvant treatment) scheduled for minimally invasive esophagectomy with gastric pull-up. After randomization, patients will either receive preoperative EPBD or a sham intervention in the routine preoperative endoscopy performed 1 day before surgery. The primary endpoint of this study will be rates of DGE, particularly those resulting from pyloric dysfunction, requiring intervention. Secondary outcomes will be major and minor postoperative complication rates, in-hospital mortality, adverse events during gastroscopy, length of ICU and hospital stay as well as postoperative pain and quality of life. In order to detect a difference between both groups at a two-sided 5% significance level, to achieve a power of 0.8 with a calculated dropout rate of approximately 20%, a sample size of 118 patients with 59 patients in every study arm will be needed.DiscussionThe presented PROPPER trial is the first multicenter RCT that will provide evidence regarding the efficacy of preoperative EPBD in reducing DGE after minimally invasive esophagectomy for cancer.Trial registrationThis trial was registered in the German Clinical Trials Register (DRKS), under the identifier DRKS00034360. Registered on May 29, 2024. The WHO trial registration data set can be found here: http://drks.de/search/en/trial/DRKS00034360 .