Pancreatic stents for the prevention of post-endoscopic retrograde cholangiopancreatography pancreatitis should be inserted up to the pancreatic body or tail

AIM To investigate the location to which a pancreatic stent should be inserted to prevent post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis(PEP).METHODS Over a ten-year period at our hospital, 296 patients underwent their first ERCP procedure and had a pancreatic stent inserted; this study included 147 patients who had ERCP performed primarily for biliary investigation and had a pancreatic stent inserted to prevent PEP. We dividedthese patients into two groups: 131 patients with a stent inserted into the pancreatic head(head group) and 16 patients with a stent inserted up to the pancreatic body or tail(body/tail group). Patient characteristics and ERCP factors were compared between the groups.RESULTS Pancreatic amylase isoenzyme(p-AMY) levels in the head group were significantly higher than those in the body/tail group [138.5(7.0-2086) vs 78.5(5.0-1266.5), P = 0.03] [median(range)]. No cases of PEP were detected in the body/tail group [head group, 12(9.2%)]. Of the risk factors for post-ERCP hyperamylasemia(≥ p-AMY median, 131 IU/L), procedure time ≥ 60 min [odds ratio(OR) 2.65, 95%CI: 1.17-6.02, P = 0.02) and stent insertion into the pancreatic head(OR 3.80, 95%CI: 1.12-12.9, P = 0.03) were identified as independent risk factors by multivariate analysis.CONCLUSION Stent insertion up to the pancreatic body or tail reduces the risk of post-ERCP hyperamylasemia and may reduce the risk of PEP.

Predictive factors for the failure of endoscopic stent-instent self-expandable metallic stent placement to treat malignant hilar biliary obstruction

AIM To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents(SEMSs). METHODS This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography(ERCP) procedures between the two groups.RESULTS The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices(ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve(sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell. CONCLUSION A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement.

Which scope is appropriate for endoscopic retrograde cholangiopancreatography after Billroth II reconstruction:An esophagogastroduodenoscope or a colonoscope?

BACKGROUND Recently,with the advent of more advanced devices and endoscopic techniques,endoscopic retrograde cholangiopancreatography(ERCP)in Billroth II(B-II)patients has been increasingly performed.However,the procedures are difficult,and the techniques and strategies have not been defined.AIM To reveal the appropriate scope for ERCP in B-II patients.METHODS Sixty ERCP procedures were performed on B-II patients between June 2005 and May 2018 at Fukushima Medical University Hospital,and in 44 cases,this was the first ERCP procedure performed by esophagogastroduodenoscopy(EGDS)or colonoscopy(CS)after B-II gastrectomy.These cases were divided into two groups:17 cases of ERCP performed by EGDS(EGDS group)and 27 cases of ERCP performed by CS(CS group).The patient characteristics and ERCP procedures were compared between the EGDS and CS groups.RESULTS The procedural time was significantly shorter in the EGDS group than in the CS group[median(range):60(20-100)vs 90(40-128)min,P value<0.01].CS was an independent factor of a longer ERCP procedural time according to the univariate and multivariate analyses(odds ratio:3.97,95%CI:1.05-15.0,P value=0.04).CONCLUSION Compared to CS,EGDS shortened the procedural time of ERCP in B-II patients.

Screening for hilar biliary invasion in ampullary cancer patients

BACKGROUND The treatment for ampullary cancer is pancreatoduodenectomy or local ampullectomy.However,effective methods for the preoperative investigation of hilar biliary invasion in ampullary cancer patients have not yet been identified.AIM To determine the necessity of and an appropriate method for investigating hilar biliary invasion of ampullary cancer.METHODS Among 43 ampullary cancer patients,34 underwent endoscopic treatment(n=9)or surgery(n=25).The use of imaging findings(thickening and enhancement of the bile duct wall on contrast-enhanced computed tomography,irregularity on endoscopic retrograde cholangiography,thickening of the entire bile duct wall on intraductal ultrasonography(IDUS),and partial thickening of the bile duct wall on IDUS)and biliary biopsy results for diagnosing hilar biliary invasion of ampullary cancer was compared.RESULTS Hilar invasion was not observed in every patient.Among the patients who did not undergo biliary stent insertion,the combination of partial thickening of the bile duct wall on IDUS and biliary biopsy results showed the highest accuracy(100%)for diagnosing hilar biliary invasion.However,each imaging method and biliary biopsy yielded some false-positive results.CONCLUSION Although some false-positive results were obtained with each method,the combination of partial thickening of the bile duct wall on IDUS and biliary biopsy results was useful for diagnosing hilar biliary invasion of ampullary cancer.However,hilar invasion of ampullary cancer is rare;therefore,the investigation of hilar biliary invasion of ampullary cancer might be unnecessary.

Present state of endoscopic ultrasonography-guided fine needle aspiration for the diagnosis of autoimmune pancreatitis type 1

Autoimmune pancreatitis(AIP)is defined as pancreatitis caused by irregular narrowing of the pancreatic duct accompanied by pancreatic swelling,fibrosis and lymphocyte infiltration,events that are related to autoimmune mechanisms.The 2010 International Consensus Diagnostic Criteria for AIP defined pancreatitis as“type 1”when increased levels of serum IgG4 were present and other organs were involved;lymphoplasmacytic sclerosing pancreatitis was the main histological characteristic.Apart from surgery,endoscopic ultrasonographyguided fine needle aspiration(EUS-FNA)is the only method for the histological diagnosis of AIP;however,this method is difficult.The use of larger-diameter FNA needles and trucut biopsy did not improve the diagnostic performance of EUS-FNA,but it has improved gradually.In this review,we look back at past efforts to improve the diagnostic performance of EUS-FNA and reveal the present state of EUS-FNA for the histological diagnosis of AIP type 1.

Can the wet suction technique change the efficacy of endoscopic ultrasound-guided fine-needle aspiration for diagnosing autoimmune pancreatitis type 1? A prospective single-arm study

BACKGROUND Other than surgery,endoscopic ultrasound-guided fine-needle aspiration(EUSFNA)is the only procedure for histologically diagnosing autoimmune pancreatitis(AIP).However,adequate specimens are difficult to obtain.Recently,more adequate specimens were reported to be obtained with EUS-FNA with a wet suction technique(WEST)than with conventional EUS-FNA.AIM To histologically diagnose AIP by EUS-FNA with a WEST.METHODS Eleven patients with possible type 1 AIP between February 2016 and August 2018 underwent EUS-FNA with a WEST(WEST group),with four punctures by 19 or 22 G needles.As a historical control,23 type 1 AIP patients who underwent no fewer than four punctures with 19 or 22 G needles were enrolled(DRY group).Patient characteristics and histological findings were compared between the two groups.RESULTS Three histopathological factors according to the International Consensus Diagnostic Criteria were significantly greater in the WEST group than the DRY group[lymphoplasmacytic infiltrate without granulocytic infiltration:9(81.8%)vs 6(26.1%),P=0.003,storiform fibrosis:5(45.5%)vs 1(4.3%),P=0.008,abundant(>10 cells/HPF)IgG4-positive cells:7(63.6%)vs 5(21.7%),P=0.026].Level 1 or level 2 histopathological findings were observed more often in the WEST group than in the DRY group[8(72.7%)vs 3(13.0%),P=0.001].CONCLUSION EUS-FNA with a WEST was more successful than standard EUS-FNA in histologically diagnosing AIP.

Pancreatic stents to prevent post-endoscopic retrograde cholangiopancreatography pancreatitis: A meta-analysis

BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)plays a major role in the investigation and treatment of pancreaticobiliary diseases.However,post-ERCP pancreatitis(PEP)is a severe adverse effect.Prior meta-analyses have shown that prophylactic PS was useful for preventing PEP.However,abstract reports and patients who underwent endoscopic ampullectomy were included in the previous analyses.In addition,two meta-analyses involved non-randomized controlled trials(RCTs).The efficacy of PS for preventing severe PEP was different in each meta-analysis.Therefore,we performed the current metaanalysis,which included only full-text articles,and added new findings.AIM To reveal the efficacy of prophylactic pancreatic stent(PS)placement for preventing PEP.METHODS We searched the MEDLINE,Cochrane Library and PubMed databases for related RCTs.Among the reports retrieved,11 studies were included in this metaanalysis.All full-text articles were published between 1993 and 2016.A total of 1475 patients were enrolled in the included studies;of these patients,734 had a PS inserted,and 741 did not have a PS inserted.PEP and severe PEP occurrence were evaluated in this meta-analysis.RESULTS PEP was observed in all studies and occurred in 39(5.3%)patients who received a PS.On the other hand,PEP occurred in 141(19%)patients who did not receive a PS.The occurrence of PEP was significantly lower in the patients who underwent PS placement than in the patients who did not receive a PS(OR=0.32;95%CI:0.23-0.45;P<0.001).In addition,the occurrence of severe PEP was evaluated.Notably,the occurrence of severe PEP was not observed in the stent group;however,the occurrence of severe PEP was observed in 8(1.3%)patients who did not have a PS inserted.Severe PEP occurred significantly less often in the stent group than in the no stent group(OR=0.24;95%CI:0.06-0.94;P=0.04).CONCLUSION In conclusion,prophylactic PS placement is useful for preventing PEP and severe PEP.

Appropriate number of biliary biopsies and endoscopic retrograde cholangiopancreatography sessions for diagnosing biliary tract cancer

BACKGROUND Biliary ductal cancer(BDC) is a lethal disease; however, diagnosing BDC is challenging. Biliary biopsies are performed to pathologically diagnose BDC, but the appropriate parameters for biliary biopsy [number of biliary biopsies, number of endoscopic retrograde cholangiopancreatography(ERCP) sessions, etc.] are unknown.AIM To clarify what constitutes an adequate method for biliary biopsy.METHODS In total, 95 patients who underwent endoscopic biliary biopsy without choledochoscopy and who were pathologically diagnosed with BDC were enrolled in this study. The patients were divided into two groups. Seventy-six patients who were diagnosed by biliary biopsy were defined as the positive group(P group), and nineteen patients who were not diagnosed by biliary biopsy were defined as the negative group(N group). The patient characteristics and ERCP-related procedures were compared between the P and N groups.RESULTS The numbers of ERCP sessions and biliary biopsies were significantly different between the two groups [ERCP sessions(one/two), P group 72/4 vs N group15/4, P value = 0.048; number of biliary biopsies, P group 2(1-6) vs N group 2(1-7), P value = 0.039]. In a multivariate analysis, fewer than 2 ERCP sessions was an independent factor influencing the positivity of the biliary biopsies.CONCLUSION This study clarified that ERCP and biliary ductal biopsy should only be performed once. If biliary cancer is not pathologically diagnosed after the first ERCP session, other methods(Endoscopic ultrasonography-guided fine needle aspiration or choledochoscopy-guided biliary ductal biopsy) should be employed.

Push vs pull method for endoscopic ultrasound-guided fine needle aspiration of pancreatic head lesions: Propensity score matching analysis

AIM To evaluate the efficacy of endoscopic ultrasoundguided fine needle aspiration(EUS-FNA) of pancreatic head cancer when pushing(push method) or pulling the echoendoscope(pull method).METHODS Overall, 566 pancreatic cancer patients had their first EUS-FNA between February 2001 and December 2017. Among them, 201 who underwent EUS-FNA for pancreatic head lesions were included in this study. EUS-FNA was performed by the push method in 85 patients, the pull method in 101 patients and both the push and pull methods in 15 patients. After propensity score matching(age, sex, tumor diameter, and FNA needle), 85 patients each were stratified into the push and pull groups. Patient characteristics and EUSFNA-related factors were compared between the two groups.RESULTS Patient characteristics were not significantly different between the two groups. The distance to lesion was significantly longer in the push group than in the pull group(13.9 ± 4.9 mm vs 7.0 ± 4.9 mm, P < 0.01). The push method was a significant factor influencing the distance to lesion(≥ median 10 mm)(P < 0.01). Additionally, tumor diameter ≥ 25 mm(OR = 1.91, 95%CI: 1.02-3.58, P = 0.043) and the push method(OR = 1.91, 95%CI: 1.03-3.55, P = 0.04) were significant factors contributing to the histological diagnosis of malignancy.CONCLUSION The pull method shortened the distance between the endoscope and the lesion and facilitated EUS-FNA of pancreatic head cancer. The push method contributed to the histological diagnosis of pancreatic head cancer using EUS-FNA specimens.

Auditory symptoms and psychological characteristics in adults with auditory processing disorders

Most adults with auditory processing disorder(APD) often have trouble at work. It is possible that these listening problems in adults with APD influence their mental health. Thus, we have to take the subject's personality and mental status into consideration when supporting subjects with APD. However, studies on APD in adults are comparatively rare. In this study, we aimed to evaluate the relationships between the results of auditory tests, APD symptoms, and psychological status in subjects with APD. This study included 22 adults who complained of listening problems in everyday life, and they underwent auditory processing tests and were questioned regarding their psychological characteristics.From the results of the auditory processing tests, all subjects showed low scores on at least one test; therefore, they were suspected of having APD. Especially, the scores were low on the auditory memory test. Furthermore, subjects with APD show relatively similar psychological characteristics to each other. However, there was no significant relationship between the results of the auditory processing tests and psychological characteristics.We have to take notice of a subject's psychological state when they perceive their listening difficulties as a large-scale problem and feel anxious as a result. For this purpose, we should take psychological characteristics into consideration at the time of the medical examination interview before audio-psychological testing.

Biliary metal stents should be placed near the hilar duct in distal malignant biliary stricture patients

BACKGROUND Endoscopic biliary drainage using a self-expandable metallic stent(SEMS)has been widely performed to treat distal malignant biliary obstruction(DMBO).However,the optimal position of the stent remains unclear.AIM To determine the ideal position for SEMS placement.METHODS In total,135 DMBO patients underwent SEMS(uncovered or covered)placement over a ten-year period.A total of 127 patients with biliary obstruction between the junction of the cystic duct and Vater’s papilla were enrolled.An SEMS was placed through the upper common bile duct 2 cm from the biliary hilar duct in 83 patients(Hilar group)or near the top of the biliary obstruction in 44 patients(Lower group).Technical and functional success,adverse events,and risk factors for SEMS dysfunction were evaluated.RESULTS The stent patency period was significantly longer in the Hilar group than in the Lower group(P value<0.01).In multivariate analysis,the only statistically significant risk factor for SEMS dysfunction was being in the Lower group(hazard ratio:9.94,95%confidence interval:2.25–44.0,P<0.01).CONCLUSION A longer patency period was achieved by positioning the SEMS near the biliary hilar duct.

Dysbiosis of the duodenal microbiota as a diagnostic marker for pancreaticobiliary cancer

BACKGROUND Pancreaticobiliary cancer(PB Ca)is a lethal disease,and a useful diagnostic marker is urgently needed.A correlation between the human microbiota and malignant gastrointestinal diseases was recently reported.AIM To investigate the efficacy of the duodenal microbiota for diagnosing PB Ca.METHODS We recruited 22 patients with benign pancreaticobiliary diseases(benign group)and 12 patients with PB Ca(malignant group).The duodenal microbiota of each patient was analyzed by the 16S rDNA terminal restriction fragment length polymorphism method.Patient characteristics,tumor markers,and relative abundances of the duodenal microbiota were compared between the benign and malignant groups.RESULTS Cancer antigen 19-9(CA19-9),Bifidobacterium,Clostridium cluster XVIII,and Prevotella levels differed significantly between the benign and malignant groups.Clostridium cluster XVIII had the greatest area under the receiver operating characteristic curve(AUC)among the four factors with respect to diagnosing PB Ca(cutoff value:3.038%;sensitivity:58.3%;specificity:95.2%;AUC:0.81).The combination of Clostridium cluster XVIII(cutoff value:3.038%)and CA19-9 Levels(cutoff value:18.8 U/mL)showed 91.7%sensitivity and 71.4%specificity for diagnosing PB Ca.CONCLUSION The duodenal microbiota may be useful for PB Ca screening.

Prevention of post-endoscopic retrograde cholangiopancreatography pancreatitis using pancreatic stents: A review of efficacy, diameter and length

Although endoscopic retrograde cholangiopancreatography (ERCP) is an important procedure for the diagnosis and treatment of pancreaticobiliary diseases, post-ERCP pancreatitis (PEP) is the most frequent adverse event that can sometimes be fatal. However, prophylactic pancreatic stent (PS) insertion has been performed to prevent PEP in high-risk patients. In some randomized controlled trials (RCTs) and meta-analyses, the efficacy of prophylactic PS insertion has been shown to prevent PEP. In addition, several types of stents have been used to decrease PEP. In this review, we introduce the details of these RCTs and meta-analyses and reveal the specifications for stent placement, for example, the stent diameter and length and the pancreatic region into which the stent should be inserted.

Correlation between Non-Alcoholic Beverage Consumption and Alcohol Drinking Behavior among Japanese Youths

The purpose of this study was to investigate the correlation between the consumption of non-alcoholic beverages (such as non-alcoholic beer, non-alcoholic cocktails, and non-alcoholic wine) and alcohol drinking behavior among Japanese youths. Data from the Japan Youth Risk Behavior Survey 2011 were analyzed. The study subjects were 9775 high school students (5026 males and 4749 females) randomly selected from the 10th to the 12th grade in 102 high schools throughout Japan. The results indicated that the percentage of youths who had consumed non-alcoholic beverages was 25.8% among males (11.5%: “one time”;14.3%: “two or more times”) and 26.1% among females (12.2%: “one time”;13.9%: “two or more times”), which suggested that at least one in four Japanese high school students had consumed non-alcoholic beverages. Those students that had consumed non-alcoholic beverages were at a significantly higher risk for alcohol-related behaviors, including “ever drank alcohol”, “current alcohol use”, “current frequent alcohol use”, and “chugging”, when compared with students who had never consumed non-alcoholic beverages. The risk for alcohol-related behaviors was higher for students who had consumed non-alcoholic beverages two or more times than for those who had consumed them one time. Specifically, the odds ratio for “ever drank alcohol” in the “one time” group was 5.16 (95% CI: 4.22 - 6.30) for males and 4.27 (95% CI: 3.53 - 5.16) for females, while it was markedly high for those in the “two or more times” group, with males at 9.78 (95% CI: 7.88 - 12.14) and females at 7.59 (95% CI: 6.20 - 9.29). The results of this study suggest that it is necessary to continuously ascertain the prevalence of non-alcoholic beverage consumption among Japanese youths. In addition, alcohol drinking prevention in youths requires attention be paid not only to their consumption of alcoholic beverages, but also to their consumption of non-alcoholic beverages.

Relationships of youth risk behaviors with norm-consciousness and resilience among Japanese high school students

The purpose of this study was to examine the influences of norm-consciousness and resilience on the prevention of youth risk behaviors among Japanese high school students. Data of a national survey, Japan Youth Risk Behavior Survey 2011, was used for this analysis. The subjects were 9778 students (5027 males, 4751 females) in grades 10-12 in 102 schools randomly selected from among high schools throughout Japan. When multiple regression analysis was carried out using four subdomains of norm-consciousness and three subdomains of resilience as the independent variables and nine risk behaviors as the dependent variables, the subdomains of norm-consciousness showed significant positive standardized partial regression coefficients for eight risk behaviors for both males and females. In particular, “current alcohol use” and “ever had sexual intercourse” showed the largest standardized partial regression coefficients for the norm-consciousness in school, and “current cigarette use” showed that for the norm-consciousness in community. The subdomains of resilience showed significant positive standardized partial regression coefficients for five risk behaviors for males and for six those for females. The results of this study suggest that the norm-consciousness is an important protective factor to comprehensively prevent risk behaviors among Japanese adolescents. It is expected to be effective to enhance the norm-consciousness particularly in school and community. In addition, resilience should also be emphasized as a factor to prevent specific risk behaviors.

Non-Axisymmetric Mass Transfer Phenomenon behind an Orifice in a Curved Swirling Flow

The purpose of this paper is to understand the mechanism of non-axisymmetric wall-thinning that caused a pipe break in the pipeline of the Mihama nuclear power plant in 2004. The wall thinning was caused by the flow accelerated corrosion which affects low carbon steel pipelines. The mass transfer rate measurement of the wall thinning behind an office in a curved swirling flow is carried out in a closed-circuit water tunnel using a benzoic acid dissolution method. The experimental results indicate that the high mass transfer rate is observed on one side of the pipe behind the orifice, which is similar to the observation of the wall-thinning rate in the Mihama case. This result suggests that the influence of the secondary flow in the long elbow combined with the swirling flow can produce the non-axisymmetric mass transfer phenomenon behind the orifice.

A Modified Methodology to Evaluate Viscosity of Non-Newtonian Liquid Foods with a Flow Channel Instrument

Through experimental analysis of the liquid flows in a flow channel instrument, prompt evaluation of the physically defined viscosity of non-Newtonian liquid foods was investigated for development into a structurally simple and easy-to-use viscometer. For Newtonian and non-Newtonian test liquids, a relation between the friction coefficient and Reynolds number, which was dimensionless as derived from an expression of analysis as a gravity current, indicated a condition under which the flow in the instrument was laminar and under which an average shear rate was on the order of less than 1 s~. Prediction organized based on this empirical relation reproduced practically the flow curve determined for the liquid foods using a rotor type viscometer. Utilization of the channel instrument as a viscometer was formulated in terms of physical meanings of measurements such as the flow length and elapsed time.

Step-Loading Characteristics of Gas Engine Cogeneration System Using Doubly-Fed Induction Generator in Stand-Alone Operation

Application of a DFIG （doubly-fed induction generator）, which is one of adjustable speed generators, to a gas engine cogeneration system has been investigated. To operate during a blackout as an emergency power supply is one of important roles for the gas engine eogeneration system. In the case of conventional constant speed of synchronous generator, the amount of the allowed step load is limited to around 30% of the rated power. On the other hand, DFIG is expected to increase the amount of step load during the stand-alone operation. In this paper, it has been demonstrated that an increase in the gas engine speed resulted in an increase in the maximum amount of step load using experimental equipment with a real gas engine. It has been concluded that the proposed system can improve the performance of an emergency power supply at step-loading.