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Effects of the repetitive current pulses of microstimulation on spatio-temporal neuronal excitations in the primary visual cortex in mouse cerebral slices in vitro were examined by utilizing the voltage-sensitive dye imaging technique. The amplitude and spatial extent of the population spike directly induced by the stimulus pulse was significantly reduced in response to successive stimulus pulses at 200 Hz. This suggested that the high-frequency microstimulation may not be efficient for inducing the neuronal spiking, at least, in vitro.

Aim: To investigate the safety and utility of an electrocautery dilation catheter for endoscopic ultrasonography (EUS)-guided pancreatic fluid collection drainage., Methods: A single-center, exploratory, retrospective study was conducted between August 2010 and August 2014. This study was approved by the Medical Ethics Committee of our institution. Informed, written consent was obtained from each patient prior to the procedure. The subjects included 28 consecutive patients who underwent EUS-guided transmural drainage (EUS-TD) for symptomatic pancreatic and peripancreatic fluid collections (PFCs) by fine needle aspiration using a 19-gauge needle. These patients were retrospectively divided into two groups based on the use of an electrocautery dilation catheter as a fistula dilation device; 15 patients were treated with an electrocautery dilation catheter (electrocautery group), and 13 patients were treated with a non-electrocautery dilation catheter (non-electrocautery group). We evaluated the technical and clinical successes and the adverse events associated with EUS-TD for the treatment of PFCs between the two groups., Results: There were no significant differences in age, sex, type, location and diameter of PFCs between the groups. Thirteen patients (87%) in the electrocautery group and 10 patients (77%) in the non-electrocautery group presented with infected PFCs. The technical success rates of EUS-TD for the treatment of PFCs were 100% (15/15) and 100% (13/13) for the electrocautery and the non-electrocautery groups, respectively. The clinical success rates of EUS-TD for the treatment of PFCs were 67% (10/15) and 69% (9/13) for the electrocautery and the non-electrocautery groups, respectively (P = 0.794). The procedure time of EUS-TD for the treatment of PFCs in the electrocautery group was significantly shorter than that of the non-electrocautery group (mean ± SD: 30 ± 12 min vs 52 ± 20 min, P < 0.001). Adverse events associated with EUS-TD for the treatment of PFCs occurred in 0 patients and 1 patient for the electrocautery and the non-electrocautery groups, respectively (P = 0.942)., Conclusion: EUS-TD using an electrocautery dilation catheter as a fistula dilation device for the treatment of symptomatic PFCs appears safe and contributes to a shorter procedure time.

Aim: To compare the clinical outcomes between 0.025-inch and 0.035-inch guide wires (GWs) when used in wire-guided cannulation (WGC)., Methods: A single center, randomized study was conducted between April 2011 and March 2013. This study was approved by the Medical Ethics Committee at our hospital. Informed, written consent was obtained from each patient prior to study enrollment. Three hundred and twenty-two patients with a naïve papilla of Vater who underwent endoscopic retrograde cholangiopancreatography (ERCP) for the purpose of selective bile duct cannulation with WGC were enrolled in this study. Fifty-three patients were excluded based on the exclusion criteria, and 269 patients were randomly allocated to two groups by a computer and analyzed: the 0.025-inch GW group (n = 109) and the 0.035-inch GW group (n = 160). The primary endpoint was the success rate of selective bile duct cannulation with WGC. Secondary endpoints were the success rates of the pancreatic GW technique and precutting, selective bile duct cannulation time, ERCP procedure time, the rate of pancreatic duct stent placement, the final success rate of selective bile duct cannulation, and the incidence of post-ERCP pancreatitis (PEP)., Results: The primary success rates of selective bile duct cannulation with WGC were 80.7% (88/109) and 86.3% (138/160) for the 0.025-inch and the 0.035-inch groups, respectively (P = 0.226). There were no statistically significant differences in the success rates of selective bile duct cannulation using the pancreatic duct GW technique (46.7% vs 52.4% for the 0.025-inch and 0.035-inch groups, respectively; P = 0.884) or in the success rates of selective bile duct cannulation using precutting (66.7% vs 63.6% for the 0.025-inch and 0.035-inch groups, respectively; P = 0.893). The final success rates for selective bile duct cannulation using these procedures were 92.7% (101/109) and 97.5% (156/160) for the 0.025-inch and 0.035-inch groups, respectively (P = 0.113). There were no significant differences in selective bile duct cannulation time (median ± interquartile range: 3.7 ± 13.9 min vs 4.0 ± 11.2 min for the 0.025-inch and 0.035-inch groups, respectively; P = 0.851), ERCP procedure time (median ± interquartile range: 32 ± 29 min vs 30 ± 25 min for the 0.025-inch and 0.035-inch groups, respectively; P = 0.184) or in the rate of pancreatic duct stent placement (14.7% vs 15.6% for the 0.025-inch and 0.035-inch groups, respectively; P = 0.832). The incidence of PEP was 2.8% (3/109) and 2.5% (4/160) for the 0.025-inch and 0.035-inch groups, respectively (P = 0.793)., Conclusion: The thickness of the GW for WGC does not appear to affect either the success rate of selective bile duct cannulation or the incidence of PEP.

Aim: To evaluate the usefulness of cytology of the pancreatic juice obtained via the endoscopic naso-pancreatic drainage tube (ENPD-C)., Methods: ENPD was performed in cases where a diagnosis could not be made other than by using endoscopic retrograde cholangiopancreatography and in cases of pancreatic neoplasms or cystic tumors, including intraductal papillary mucinous neoplasm (IPMN) suspected to have malignant potential. 35 patients (21 males and 14 females) underwent ENPD between January 2007 and June 2013. The pancreatic duct was imaged and the procedure continued in one of ENPD-C or ENPD-C plus brush cytology (ENPD-BC). We checked the cytology result and the final diagnosis., Results: The mean patient age was 69 years (range, 48-86 years). ENPD-C was performed in 24 cases and ENPD-C plus brush cytology (ENPD-BC) in 11 cases. The ENPD tube was inserted for an average of 3.5 d. The final diagnosis was confirmed on the basis of the resected specimen in 18 cases and of follow-up findings at least 6 mo after ENPD in the 18 inoperable cases. Malignancy was diagnosed in 21 cases and 14 patients were diagnosed as having a benign condition. The ratios of class V/IV:III:II/I findings were 7:7:7 in malignant cases and 0:3:11 in benign cases. The sensitivity and specificity for all patients were 33.3% and 100%, respectively. The cytology-positive rate was 37.5% (6/16) for pancreatic cancer. For IPMN cases, the sensitivity and specificity were 33% and 100%, respectively., Conclusion: Sensitivity may be further increased by adding brush cytology. Although we can diagnosis cancer in cases of a positive result, the accuracy of ENPD-C remains unsatisfactory.

A 59-year-old man diagnosed with Stage IV advanced gastric cancer due to pancreatic invasion(T4)and splenic hilum lymph node metastasis(N3)was initially treated with neoadjuvant chemotherapy using S-1 and CDDP. However, it was discontinued because the tumor marker increased after 1 course. Instead of S-1 and CDDP, S-1 and paclitaxel were then administered. After 4 courses, CT scan revealed reduced tumor size and the disappearance of splenic hilum lymph node swelling that indicated PR of the chemotherapy. Moreover, serum CEA was remarkably decreased to 77 ng/mL from 1,092 ng/mL. He could undergo subtotal gastrectomy(Billroth II)with lymph node dissection(D2)and cholecystectomy. Histopathological examination revealed Stage II (pT2(SS), pN1, CY0, ly1, v2)advanced gastric cancer that showed good effect of S-1 and paclitaxel. At this writing (October 2007), the patient has remained free of disease for more than 1 year and 6 months with good nutrition. Neoadjuvant chemotherapy using S-1 and paclitaxel for advanced gastric cancer seems to have been effective.

Aim: To introduce a new method: small endoscopic sphincterotomy (ES) combined with endoscopic papillary large balloon dilation (SES + EPLBD) to treat patients with large biliary stones., Methods: Retrieval of large biliary stones was performed in 88 patients. Mean stone size was 14 +/- 3 mm and mean number of stones was 2.5 +/- 3.5. Firstly, ES with a small incision was performed. Next, endoscopic papillary dilation was performed with a large balloon to slowly match the size of the bile duct. Stones were then retrieved from the biliary duct with a balloon and a basket., Results: Stone retrieval was successful in all cases except one cystic duct stone case without the need to crush large stones. Mean procedure time was 30 +/- 5 min. Dilating the papillary orifice with a large balloon made it possible to remove large stones smoothly without crushing them. After dilation with the large balloon, there were some instances of oozing, but no perforations. One instance of post-procedural pancreatitis (1%) occurred., Conclusion: SES + EPLBD was effective for the retrieval of large biliary stones without the use of mechanical lithotripsy.