Ultrafast Frequency-Shift Dynamics at Temporal Boundary Induced by Structural-Dispersion Switching of Waveguides.

We experimentally demonstrate the observation of a frequency-shift dynamics at a temporal boundary in the terahertz (THz) region relying on a scheme that controls the structural dispersion of a metal-semiconductor waveguide. Ultrafast structural-dispersion switching is achieved within a subpicosecond timescale by illuminating a waveguide surface with an optical pump pulse during the propagation of a THz pulse in the waveguide. Owing to the relatively high conversion efficiency, up to 23%, under the condition that the frequency shift is sufficiently larger than the bandwidth of the incident pulse, the rapid variation of the THz frequency around the temporal boundary is directly observed in the time domain.

[A case of mucinous cystic neoplasm of the liver].

We present a case of resected mucinous cystic neoplasm of the liver in a 71-year-old woman admitted to our hospital with epigastric discomfort. Abdominal ultrasonography and computed tomography revealed a multi-locular cystic tumor measuring 35 mm in diameter in segment IV of the liver. Left hepatic lobectomy was performed based on the diagnosis of mucinous cystic neoplasm of the liver; subsequent histology revealed that the tumor was multi-locular, cystic, and lined with a single layer of columnar epithelium with low-grade atypia and was associated with a typical ovarian-like stroma. There was no evidence (imaging or histological) to support communication of the cyst with the intrahepatic bile duct, despite modest bile deposition being observed in the cystic wall. The definitive diagnosis was mucinous cystic neoplasm with low-grade intrahepatic epithelial neoplasia.

[Clinicopathological study of acute esophageal mucosal lesion].

Acute esophageal mucosal lesion (AEML) is a comprehensive disease that includes necrotizing esophagitis and acute erosive esophagitis, which result in upper gastrointestinal bleeding. However, little is known about AEML. We examined the clinicopathological features of 57 AEML cases. AEML presented as acute diffuse esophagitis showing an endoscopically erosive mucosa. The disease did not include corrosive injury, radiation-induced damage, infectious esophagitis, or acute exacerbation of chronic gastroesophageal reflux disease. AEML predominantly affected elderly men, and upper gastrointestinal bleeding was the frequent presenting symptom. Severe underlying diseases such as cranial nerve disease or pneumonia were observed in 98% of the patients. Esophageal sliding hernia and gastroduodenal ulcers were endoscopically observed in 67% and 63% of the patients, respectively. Deaths due to exacerbation of the underlying diseases accounted for 16%. Most cases rapidly improved with conservative management using a proton pump inhibitor or an H2 blocker. Therefore, AEML should be considered a disease having characteristics different from those of common gastroesophageal reflux disease.

Single-stage endoscopic treatment for mild to moderate acute cholangitis associated with choledocholithiasis: a multicenter, non-randomized, open-label and exploratory clinical trial.

BACKGROUND: Two-stage treatment involving stone removal after drainage is recommended for mild to moderate acute cholangitis associated with choledocholithiasis. However, single-stage treatment has some advantages. We aimed to assess the efficacy and safety of single-stage endoscopic treatment for mild to moderate acute cholangitis associated with choledocholithiasis. METHODS: A multicenter, non-randomized, open-label, exploratory clinical trial was performed in 12 institutions. A total of 50 patients with a naïve papilla and a body temperature ≥37 °C who were diagnosed with mild to moderate cholangitis associated with choledocholithiasis were enrolled between August 2012 and February 2014. RESULTS: Of the 50 patients, 15 had mild cholangitis and 35 had moderate cholangitis. The median number of common bile duct stones was 2 (range, 1-8), and the median diameter of the common bile duct stones was 7.5 mm (range, 1-18). The cure rate of acute cholangitis within 4 days after single-stage treatment was 90% (45/50) based on a body temperature <37 °C for ≥24 h. The incidence of complications was 10% (5/50). CONCLUSION: Single-stage endoscopic treatment may be effective and safe for mild to moderate acute cholangitis associated with choledocholithiasis (clinical trial registration number: UMIN000008494).