Biliary spontaneous dislodgement spiral stent for patients who underwent mechanical lithotripsy

BACKGROUND The incidence of post-endoscopic retrograde cholangiopancreatography(ERCP)cholangitis(PEC)in patients who underwent mechanical lithotripsy(ML)for large stone removal is high(up to 13.3%).One of the main causes is remaining small fragments or sludge that can impair normal biliary drainage.Endoscopic placement of a nasobiliary tube or a conventional plastic biliary stent has been commonly used under such conditions,but the patient may suffer from significant discomfort after the placement of a nasobiliary tube,while additional endoscopy is required for stent removal.We developed a biliary spontaneous dislodgement spiral stent(BSDSS)to overcome those shortcomings.AIM To evaluate the feasibility,safety,and effectiveness of inserting a BSDSS for patients who underwent ML for large stone removal.METHODS We conducted a single-center,retrospective,cohort study at West China Hospital,Sichuan University.A total of 91 consecutive patients with large biliary stones(≥10 mm)in the common bile duct who underwent ML between November 2017 and July 2018 were included.The 49 eligible patients were divided into the BSDSS group and the nasobiliary tube group.Technical success,post-ERCP adverse events(including PEC,post-ERCP pancreatitis,stone recurrence,BSDSS retention,self-extraction and dislocation of the nasobiliary tube),drainage time,and postoperative stay were measured and compared.RESULTS Twenty-one patients in the BSDSS group and 28 patients in the nasobiliary tube group were included in the analyses.The baseline characteristics and clinical information were similar in the two groups.Insertions of BSDSS and nasobiliary tube were technically successful in all 49 patients.There was no significant difference in the incidence of overall post-ERCP adverse events between the two groups(4.8%in the BSDSS group vs 17.9%in the nasobiliary tube group,P=0.219).The median duration of drainage time(3 d in the BSDSS group vs 4 d in the nasobiliary tube group)and length of postoperative stay(4 d in the BSDSS group vs 5 d in the nasobiliary tube group)also did not differ(P=0.934,and P=0.223,respectively).CONCLUSION Endoscopic placement of a BSDSS appears to be feasible,safe and effective for patients who underwent ML for large stone removal.

Resistance of grid steel-tube-confined concrete targets against projectile impact: Experimental investigation and analytical engineering model

Steel-tube-confined concrete(STCC) targets are provided with excellent anti-penetration performance over semi-infinite concrete(SIC) targets since the steel tube imposes passive restraint on the in-filled concrete during the penetration process. Grid STCC system with square steel tubes is a potential solution to protective structures. In this paper, experiments of 9-cell grid STCC targets penetrated by 12.7 mm Armor Piercing Projectile(APP) were performed. The influence of side length and thickness of steel tube,steel ratio and impact velocity on anti-penetration performance were taken into account. Additionally,single-cell square STCC targets were also designed and tested for comparison with the 9-cell grid STCC targets. Damage modes and parameters of the tested targets were measured and discussed. Moreover,the stiffness of radial confinement of grid STCC targets is achieved according to the elastic solution of infinite cylindrical shell in Winkler medium. Furthermore, the penetration resistance and depth of penetration(DOP) for grid STCC targets are obtained on the basis of the dynamic finite spherical cavityexpansion(FSCE) models including radial confinement effect. It is shown that the 9-cell grid STCC targets with optimal dimension match of thickness and side length of steel tube can reduce the DOP by about17 % and 23 % in comparison with the SIC targets and single-cell square STCC targets, respectively, due to both the confinement of square steel tube to concrete in the impacted cell and the additional confinement of the surrounding cells to the impacted cell;the penetration resistance and DOP of the grid and cellular STCC targets with similar steel ratio is close, and thus the grid STCC targets with simpler manufacturing process and excellent in-plane expandability are preferred in engineering practice;moreover, the predicted results of DOP model based on the FSCE models agree well with the tested results with the maximum disparity less than 12 % and the proposed model is more applicable to the grid and cellular STCC targets with high radial confinement.

New antireflux plastic stent for patients with distal malignant biliary obstruction

BACKGROUND Endoscopic biliary stenting is a well-established palliative treatment for patients with unresectable distal malignant biliary obstruction(MBO). However, the main problem with stent placement is the relatively short duration of stent patency.Although self-expanding metal stents(SEMSs) have a longer patency period than plastic stents(PSs), the higher costs limit the wide use of SEMSs. A PS with an antireflux valve is an attractive idea to prolong stent patency, but no ideal design for an antireflux PS(ARPS) has been proposed. We developed a new ARPS with a "duckbilled" valve attached to the duodenal end of the stent.AIM To compare the patency of ARPSs with that of traditional PSs(TPSs) in patients with unresectable distal MBO.METHODS We conducted a single-center, prospective, randomized, controlled, double-blind study. This study was conducted at the West China Hospital of Sichuan University. Consecutive patients with extrahepatic MBO were enrolled prospectively. Eligible patients were randomly assigned to receive either an ARPS or a TPS. Patients were followed by clinic visits or telephone interviews every 1-2 mo until stent exchange, death, or the final study follow-up in October 2018. The primary outcome was the duration of stent patency. Secondary outcomes included the rate of technical success, the rate of clinical success,adverse events, and patient survival.RESULTS Between February 2016 and December 2017, 38 patients were randomly assigned to two groups, with 19 patients in each group, to receive ARPSs or TPSs. Stent insertion was technically successful in all patients. There were no significant differences between the two groups in the rates of clinical success or the rates of early or late adverse events(P = 0.660, 1.000, and 1.000, respectively). The median duration of stent patency in the ARPS group was 285 d [interquartile range(IQR),170], which was significantly longer than that in the TPS group(median, 130 d;IQR, 90, P = 0.005). No significant difference in patient survival was noted between the two groups(P = 0.900).CONCLUSION The new ARPS is safe and effective for the palliation of unresectable distal MBO,and has a significantly longer stent patency than a TPS.

Intestinal ischemia-reperfusion of macaques triggers a strong innate immune response

AIM:To investigate inflammatory injury in the intestinal mucosa after intestinal ischemia-reperfusion(ⅡR) with Toll-like receptor(TLR)-mediated innate immunity.METHODS:Ten macaques were randomized into control and ⅡR groups.The distribution and expression level of TLR2,TLR4,MD2,nuclear factor(NF)-κB p65 and interferon(IFN)-γ were measured by immunohistochemical stain and western blotting.The mRNA expression of TLR4,TLR2,MD2,interleukin(IL)-1β and tumor necrosis factor(TNF)-α were measured by reverse transcriptase-polymerase chain reaction.The cytokine levels in blood and intestinal tissues were measured by ELISA.RESULTS:Obvious hemorrhage and erosion of mucosae were seen in the ⅡR group.Expression of TLR2,TLR4,MD2,NF-κB p65 and IFN-γ was significantly higher in the ⅡR group than in the control group(0.13 ± 0.04,0.22 ± 0.04,0.16 ± 0.06,0.65 ± 0.12,0.38 ± 0.10 vs 0.07 ± 0.04,0.08 ± 0.03,0.04 ± 0.02,0.19 ± 0.06,0.14 ± 0.05,P < 0.05).In addition,the expression of TLR2,TLR4,MD2,IL-1β and TNF-α mRNA in the ⅡR group were significantly higher than those of control group(1.52 ± 0.15,1.39 ± 0.06,1.94 ± 0.12,1.48 ± 0.15,0.66 ± 0.08 vs 0.31 ± 0.05,0.5 ± 0.04,0.77 ± 0.05,0.35 ± 0.08,0.18 ± 0.04,P < 0.05).Furthermore,IL-1β,IL-6 and TNF-α levels in the macaques ileum and plasma were significantly higher than in the control group(plasma:86.3 ± 15.2,1129 ± 248.3,77.8 ± 16.2 vs 29.5 ± 7.3,19.8 ± 8.2,5.6 ± 1.7; ileum:273.4.± 44.7,1636 ± 168.0,205.5 ± 30.7 vs 76.8 ± 20.5,663.4 ± 186.9,49.0 ± 9.4; P < 0.05).CONCLUSION:After ⅡR,general inflammatory injury in the intestinal mucosa is correlated with a strong innate immune response,mediated by activation of the TLR-NF-κB-cytokine pathway.

^(12)CO,^(13)CO and C^(18)O observations along the major axes of nearby bright infrared galaxies

We present simultaneous observations of 12CO,13CO and C18O J=1-0 emission in 11 nearby(cz<1000 km s-1) bright infrared galaxies.Both 12CO and 13CO are detected in the centers of all the galaxies,except for 13CO in NGC 3031. We have also detected C18O,CSJ=2-1 and HCO+J=1-0 emission in the nuclear regions of M82 and M51.These are the first systematical extragalactic detections of 12CO and its isotopes from the PMO 14 m telescope.We have conducted half-beam-spaced mapping of M82 over an area of 4×2.5 and major axis mapping of NGC 3627,NGC 3628,NGC 4631 and M51.The radial distributions of 12CO and 13CO in NGC 3627,NGC 3628 and M51 can be well fitted by an exponential profile. The 12CO/13CO intensity ratio,R,decreases monotonically with the galactocentric radius in all mapped sources.The average R in the center and disk of the galaxies are 9.9±3.0 and 5.6±1.9,respectively,much lower than the peculiar R(～24) found in the center of M82.The intensity ratios of 13CO/C18O,13CO/HCO+and 13CO/CS(either our or literature data) show little variation with galactocentric radius,in sharp contrast with the greatly varied R.This supports the notion that the observed gradient in R could be the result of the variations of the physical conditions across the disks.The H2 column density derived from C18O shows that the Galactic standard conversion factor(X-factor) overestimates the amount of the molecular gas in M82 by a factor of～2.5.These observations suggest that the X-factor in active star-forming regions(i.e.,nuclear regions) should be lower than that in normal star-forming disks and the gradient in R can be used to trace the variations of the X-factor.

New anti-reflux plastic stent to reduce the risk of stent-related cholangitis in the treatment of biliary strictures

BACKGROUND There is little data available on the role of new anti-reflux plastic stents(ARPSs).AIM To compare the use of ARPSs with that of traditional plastic stents(TPSs)for patients with biliary strictures.METHODS Consecutive patients with biliary strictures who underwent first endoscopic biliary stenting between February 2016 and May 2019 were included.The onset of stent-related cholangitis,stent patency,clinical success,and other adverse events were evaluated.RESULTS Sixty-seven patients in the ARPS group and 66 patients in the TPS group were included in the final analyses.Fewer patients experienced stent-related cholangitis in the ARPS group than that in the TPS group(8 patients vs 18 patients;P=0.030).The median time till the onset of first stent-related cholangitis was later in the ARPS group than that in the TPS group(128.5 d vs 76 d;P=0.039).The cumulative median stent patency in the ARPS group was 185 d,which was significantly longer than that in the TPS group(133 d;P=0.001).The clinical success rates and other adverse events did not significantly differ between both groups.CONCLUSION Placement of new ARPS might be a safe and effective optional therapeutic strategy to reduce the risk of stent-related cholangitis and prolong stent patency.

Peroral endoscopic myotomy for management of gastrointestinal motility disorder

Achalasia is a type of esophageal motility disorder,consisting of relaxation dysfunction of the lower esophagus and disturbed esophageal peristalsis.Related clinical symptoms include dysphagia,regurgitation,chest pain,and weight loss.Traditional treatment options include endoscopic botulinum toxin injection,endoscopic pneumatic dilation,and laparoscopic Heller’s myotomy.These therapies mainly relieve symptoms by reducing the pressure on the lower esophageal sphincter and reducing blood flow resistance at the esophagogastric junction.Based on endoscopic submucosal dissection and natural orifice transluminal endoscopic surgery,peroral endoscopic myotomy(POEM)is a purely endoscopic method of myotomy with minimal invasiveness and a low rate of adverse events when performed by experienced operators.Since then,numerous studies have shown the significant clinical efficacy and safety of POEM.The purpose of this article is to introduce different modified POEMs,special indications for different POEMs,and their advantages as well as disadvantages.