Concomitant endoscopic radiofrequency ablation and laparoscopic reflux operative results in more effective and efficient treatment of Barrett esophagus

BACKGROUND: Barrett esophagus (BE) caused by gastroesophageal reflux disease can lead to esophageal cancer. The success of endoscopic treatments with BE eradication depends on esophageal anatomy and post-treatment acid exposure. STUDY DESIGN: Between January 2008 and December 2009, 10 patients were selected for combination treatment of BE using laparoscopic anti-reflux surgery and endoscopic radiofrequency ablation. Retrospective review of preoperative, procedural, and postoperative data was performed. RESULTS: Seven study patients had a pathologic diagnosis of nondysplastic BE and 3 patients had a diagnosis of low-grade dysplasia. Average length of BE lesions was 6.4 ± 4.8 cm. Procedure time averaged 154.4 ± 46.4 minutes. At the time of surgery, the mean number of ablations performed was 4.39 ± 1.99. Six patients were noted to have major hiatal hernias requiring reduction. Five patients (80%) had 100% resolution of their BE at their first postoperative endoscopy. The remaining 3 patients had a ≥50% resolution and underwent subsequent endoscopic ablation. Symptomatic results revealed that 4 patients had substantial dysphagia to solids and other symptoms were minimal. Two patients were noted to have complications related to the ablative treatments. One stricture and 1 perforation were observed. CONCLUSIONS: Endoscopic radiofrequency ablation of BE at the time of laparoscopic fundoplication is feasible and can effectively treat BE lesions. A single combined treatment can result in fewer overall procedures performed to obtain BE eradication

Fluorescence Quantum Yield of Thioflavin T in Rigid Isotropic Solution and Incorporated into the Amyloid Fibrils

In this work, the fluorescence of thioflavin T (ThT) was studied in a wide range of viscosity and temperature. It was shown that ThT fluorescence quantum yield varies from 0.0001 in water at room temperature to 0.28 in rigid isotropic solution (T/η→0). The deviation of the fluorescence quantum yield from unity in rigid isotropic solution suggests that fluorescence quantum yield depends not only on the ultra-fast oscillation of ThT fragments relative to each other in an excited state as was suggested earlier, but also depends on the molecular configuration in the ground state. This means that the fluorescence quantum yield of the dye incorporated into amyloid fibrils must depend on its conformation, which, in turn, depends on the ThT environment. Therefore, the fluorescence quantum yield of ThT incorporated into amyloid fibrils can differ from that in the rigid isotropic solution. In particular, the fluorescence quantum yield of ThT incorporated into insulin fibrils was determined to be 0.43. Consequently, the ThT fluorescence quantum yield could be used to characterize the peculiarities of the fibrillar structure, which opens some new possibilities in the ThT use for structural characterization of the amyloid fibrils

Relativistic electron beams driven by kHz single-cycle light pulses

International audienceLaser-plasma acceleration(1,2) is an emerging technique for accelerating electrons to high energies over very short distances. The accelerated electron bunches have femtosecond duration(3,4), making them particularly relevant for applications such as ultrafast imaging(5) or femtosecond X-ray generation(6,7). Current laser-plasma accelerators deliver 100 MeV (refs 8-10) to GeV (refs 11, 12) electrons using Joule-class laser systems that are relatively large in scale and have low repetition rates, with a few shots per second at best. Nevertheless, extending laser-plasma acceleration to higher repetition rates would be extremely useful for applications requiring lower electron energy. Here, we use single-cycle laser pulses to drive high-quality MeV relativistic electron beams, thereby enabling kHz operation and dramatic downsizing of the laser system. Numerical simulations indicate that the electron bunches are only similar to 1 fs long. We anticipate that the advent of these kHz femtosecond relativistic electron sources will pave the way to applications with wide impact, such as ultrafast electron diffraction in materials(13,14) with an unprecedented sub-10 fs resolution(15)