Initial evaluation of a novel multibending backward-oblique viewing duodenoscope in endoscopic retrograde cholangiopancreatography.

A novel multibending backward-oblique viewing duodenoscope was developed to overcome the difficult technical aspect of deep cannulation into the bile duct during endoscopic retrograde cholangiopancreatography (ERCP). The aim of the present study was to evaluate the initial experience of a novel multibending backward-oblique viewing duodenoscope (M-D scope) for ERCP. This was a retrospective review of 23 patients with native papilla who received biliary ERCP with the M-D scope between April and December 2010. The procedures were performed by two well-experienced endoscopists. In all patients, biliary cannulation and therapeutic procedure were successfully completed. In two patients with Billroth I gastrectomy, ERCP were initially attempted with a conventional single-bending duodenoscope, but biliary cannulations were unsuccessful. However, with the use of the M-D scope, biliary cannulation and therapeutic procedures were successfully completed. A novel multibending backward-oblique viewing duodenoscope is safe and feasible for therapeutic and diagnostic ERCP.

The safety of a mucosal vaccine using the C-terminal fragment of Clostridium perfringens enterotoxin.

The C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE) is a claudin-4 binder. Very recently, we found that nasal immunization of mice with C-CPE-fused antigen activated antigen-specific humoral and mucosal immune responses and that the deletion of the claudin-4-binding domain attenuated the immune responses. C-CPE-fusion strategy may be useful for mucosal vaccination. C-CPE is a fragment of enterotoxin, and the safety of C-CPE-fused protein is very important for its future application. In the present study, we investigated whether C-CPE-fused antigen induces immune responses without mucosal injury by using ovalbumin (OVA) as a model antigen. Immunohistochemical analysis showed that claudin-4 was expressed in epithelial cell sheets bordering the nasal cavity. Nasal immunization with C-CPE-fused OVA dose-dependently elevated the OVA-specific serum IgG titer, which was 1000-fold greater than the titer achieved by immunization with OVA or a mixture of OVA and C-CPE at 5 microg of OVA. Nasal immunization with C-CPE-fused OVA (5 microg of OVA) activated Th1 and Th2 responses. Histological analysis showed no mucosal injury in the nasal cavity or nasal passage. C-CPE-fused OVA exhibited mucosal vaccination without mucosal injury. These findings indicate thatclaudin-4-targeting using C-CPE can be a potent strategy for mucosal vaccination.

A pilot study of EUS-guided hot saline injection for induction of pancreatic tissue necrosis.

BACKGROUND AND STUDY AIMS: Hot saline may be potentially useful for inducing necrosis of pancreatic tissue. However, the local and systemic effects are largely unknown. This pilot study aimed to evaluate the feasibility and safety of EUS-guided injection of hot saline into the pancreas in the porcine model. METHODS: Boiling hot saline was injected into the tail of normal porcine pancreas under EUS guidance in six pigs via a transgastric approach. Three pigs were killed 4 hours later to study the acute effect of the hot saline injection (acute study). The remaining three pigs were killed after 7 days of clinical observation (survival study). RESULT: Injection of 5 mL, 2 mL and 1 mL of hot saline produced localized necrosis (7 - 10 mm) of pancreatic tissue in the acute study. However, there was pooling of hot saline on the surface of the pancreas when 5mL was injected. On the basis of the results of the acute study, the volume of hot saline injected in the survival study was 1 mL. One milliliter of hot saline produced localized or sporadic necrosis of pancreatic tissue without any signs of pancreatitis in all three pigs in the survival study; hot saline was observed to pool on the pancreatic surface of one pig. There was no histological evidence of necrosis in the pancreatic tissue adjacent to the pooled hot saline in either the acute or the survival study. CONCLUSION: EUS-guided hot saline injection of pancreatic tissue in the porcine model was technically successful and led to localized necrosis of pancreatic tissue without any sign of pancreatitis.

Use of the curved linear-array echo endoscope to identify gastrorenal shunts in patients with gastric fundal varices.

BACKGROUND AND STUDY AIMS: : Balloon-occluded retrograde transvenous obliteration (B-RTO) has emerged as an effective, minimally invasive treatment for fundal varices. B-RTO requires a spontaneously developed gastrorenal shunt as a pathway for the balloon catheter to reach the fundal varices. We used a curved linear-array (CLA) echo endoscope in patients with fundal varices to identify gastrorenal shunts, and compared the detection rate with the gold standard, contrast-enhanced computed tomography (CECT). PATIENTS AND METHODS: A total of 40 patients with fundal varices were examined with both CLA echo endoscopy and CECT. The CECT images were retrospectively and independently evaluated by two gastroenterologists who were unaware of the clinical details, including the results of the CLA echo endoscopy. RESULTS: CLA echo endoscopy identified gastrorenal shunts in 26/40 patients with fundal varices. It visualized the shunt in a longitudinal direction and provided images of the connections of the shunt at both ends, the fundal varices and the left renal vein/branch of the inferior adrenal vein. The kappa index for CLA echo endoscopy and CECT for the identification of gastrorenal shunt was 0.9 (95 % CI, 0.6 to 1.0). When the cutoff point for the diameter of the gastrorenal shunt detected by the CLA echo endoscope was set at equal to or greater than 5 mm, the kappa index was 1.0 (95 % CI, 0.7 to 1.0). CONCLUSIONS: These results suggest that CLA echo endoscopy can successfully identify gastrorenal shunt and provide detailed morphological information. It also efficiently identifies patients suitable for B-RTO, particularly in cases of acute bleeding. It also has considerable potential for providing detailed information with regard to the treatment of gastric varices.

Hemodynamic analysis of esophageal varices using color Doppler endoscopic ultrasonography to predict recurrence after endoscopic treatment.

BACKGROUND AND STUDY AIMS: The time to recurrence of esophageal varices may vary greatly between patients even after the same endoscopic therapy. To clarify the factors which contribute to recurrence after endoscopic treatment, the hemodynamics and morphology of the left gastric vein (LGV) were investigated using color Doppler endoscopic ultrasonography (EUS). PATIENTS AND METHODS: A total of 31 patients with high-risk esophageal varices underwent color Doppler-EUS before receiving endoscopic variceal ligation and endoscopic injection sclerotherapy combined therapy. Endoscopic examination was performed every 3 months after the treatment to evaluate recurrence of varices. RESULTS: A total of 18 patients responded to the therapy, while 13 patients did not respond, and had recurrence within 12 months. The hepatofugal flow velocity in the LGV trunk was significantly lower in the responders (9.9 vs. 13.9 cm/sec; P = 0.02). The branch pattern of the LGV was categorized into three groups: anterior branch dominant, posterior branch dominant, and no-dominant type. The incidence of the anterior branch dominant type was significantly less in responders (17 vs. 70 %; P = 0.01). There was no significant difference in the LGV trunk diameter and the size of the paraesophageal vein between the two groups. CONCLUSION: Risk factors for recurrence can be analyzed in detail using color Doppler-EUS. Further investigation using color Doppler-EUS may enable us to select the optimal way to treat esophageal varices to prevent recurrence.

Low power diode laser treatment using indocyanine green for eradication of esophageal varices.

BACKGROUND AND STUDY AIMS: Endoscopic variceal ligation (EVL) is an alternative to sclerotherapy for the treatment of esophageal varices, but is associated with higher rates of recurrence and subsequent bleeding than sclerotherapy. To prevent recurrence of varices after EVL, we have developed a low-dose diode laser therapy combined with the injection of indocyanine green, which allows enhanced tissue absorption of the laser beam selectively around varices. In this study we investigated the efficacy and safety of this technique. PATIENTS AND METHODS: Eight patients with F2 or F3 esophageal varices were enrolled. At 1 week after EVL, indocyanine green solution (1 mg/ml) was injected submucosally around the remaining varices. A diode laser (power 10 watts) was applied to the surface from the esophagogastric junction to 5 cm above it. The spot size was kept to 5 mm in diameter. RESULTS: Laser irradiation was performed safely, without bleeding from the varices, or perforation. There were no major complications. Endoscopy 1 month later showed F0 forms in seven patients, F1 in one patient, and no red color sign in any patient. No recurrence of varices has been observed in any of the patients during the follow-up period of at least 12 months. CONCLUSION: This technique may provide a simple, safe and effective procedure, as an additional treatment to EVL, for the prevention of recurrence of esophageal varices.

Pilot study of the heterogeneous patterns of masticatory muscle coordination in nonpatient population.

This pilot study characterized coordination patterns of the muscles of mastication during voluntary chewing in a nonclinical population. Dental students (n = 177) who did not exhibit symptoms of temporomandibular disorder were screened by a comprehensive muscle and temporomandibular joint palpation examination. A group of 44 students was identified on the basis of the presence of four or more tender points indicated during palpation. This group was further subgrouped by the absence (group A-1) and presence (group A-2) of temporomandibular joint clicking. Five volunteers from groups A-1 and A-2 and five volunteers without any palpation tenderness and joint clicking (control group) were examined by simultaneous recordings of electromyography of bilateral masseter and posterior one third of the temporalis muscles and by mandibular kinesiography. The electromyographic coordination pattern for the control group demonstrated predominantly working masseter muscle activity. This "predominant working masseter" pattern was not observed in groups A-1 or A-2. Additional analyses of the recordings indicated that a hypoactive tendency of the working side masseter muscle particularly outlasting the tooth contact was present in group A-1, whereas significant hyperactivity of the posterior one third of the temporalis was present in group A-2. The data suggested that an asymptomatic nonpatient population may be functionally diverse.