PD-L1 expression combined with microsatellite instability/CD8+tumor infiltrating lymphocytes as a useful prognostic biomarker in gastric cancer

While the importance of programmed death-ligand 1 (PD-L1), mutation burden caused by microsatellite instability (MSI), and CD8+ tumor infiltrating lymphocytes (TILs) has become evident, the significance of PD-L1 expression on prognosis still remains controversial. We evaluated the usefulness of combined markers of PD-L1 and MSI or CD8+ TILs as a prognostic biomarker in gastric cancer. A total of 283 patients with gastric cancer were reviewed retrospectively. PD-L1 expression on >5% tumor cells was defined as PD-L1-positive. PD-L1-positive rate was 15.5% (44/283). PD-L1 positivity was significantly correlated with invasive and advanced cancer and also significantly correlated with MSI, whereas no significance was observed with CD8+ TILs. Kaplan-Meier analysis showed that PD-L1 positivity significantly correlated with a poor prognosis (p = 0.0025). Multivariate analysis revealed that PD-L1 positivity was an independent poor prognostic factor (hazard ratio [HR]: 1.97, p = 0.0106) along with diffuse histological type and lymph node metastases. Combinations of PD-L1 and MSI (HR: 2.18) or CD8+ TILs (HR: 2.57) were stronger predictive factors for prognosis than PD-L1 alone. In conclusion, combined markers of PD-L1 and MSI or CD8+ TILs may be more useful prognostic biomarkers in gastric cancer, and better clarify the immune status of gastric cance

Observation of Flaking Process in Rolling Contact Fatigue by Laminography Using Ultra-bright Synchrotron Radiation

The flaking failure in rolling contact fatigue (RCF) results from crack initiation and propagation has been believed to originate from non-metallic inclusions located beneath the surface. With conventional microscopies, however, damage process in the internal region of materials could not be observed, then RCF crack initiation and propagation behaviours were observed by using synchrotron radiation computed laminography (SRCL) in the brightest synchrotron facility in Japan, and the effect of the inclusion orientation on the RCF property was examined. In our previous studies, crack initiation and propagation behaviours caused by extended MnS inclusions distributed in depth or transverse (width) direction was observed by the SRCL. In the present study, the fracture mechanism under RCF was discussed on specimens with MnS inclusions distributed in the rolling direction. As a result, vertical cracks were initiated on the surface, parallel to the ball-rolling direction in specimens. The crack propagation direction was then changed perpendicular to the rolling direction. Thereafter, similar with our previous studies, vertical cracks caused the horizontal cracks beneath the surface, when the vertical cracks reached to a critical length. The ratio of the vertical crack initiation life to the flaking life was higher than specimens with other inclusion orientation

Prototype of TlBr Detector Array for Ultra High Resolution PET

We developed a prototype of TlBr semiconductor detector array for high resolution PET scanner with less than 1mm FWHM. We obtained an energy resolution of similar to 20% FWHM for 511 keV and a coincidence time resolution of similar to 50nsec FWHM at a detector bias 100V. This result expects the capability of application of TlBr detector array to a high resolution PET scanner. The TlBr detector arrays with the present time resolution performance can be applied to a small PET scanner for the PET study using small animals such as rats and mice

A Case Report of Non-typical Annular Pancreas Diagnosed during Laparoscopic Gastric Surgery

An annular pancreas is a rare anomaly of the pancreas, defined as pancreatic tissue that totally or partly encircles the duodenum, usually the descending portion. A 76-year-old man who was diagnosed with gastric cancer cT3N0M0 Stage IIB underwent laparoscopic distal gastrectomy with D2 lymph node dissection. Intraoperatively, the dorsal half of the duodenal bulb was seen to be half surrounded by the pancreas, and a non-typical annular pancreas was diagnosed. Because of the risk to the pancreas, it was considered impossible to perform anastomosis by a linear stapler as in the usual laparoscopic procedure. Therefore, we performed laparoscopically assisted distal gastrectomy and Billroth-I reconstruction using a circular stapler, and the surgery was completed without difficulties. His postoperative course was good despite the development of a pancreatic fistula, which was an International Study Group for Pancreas Fistula biochemical leak. Some APs can be diagnosed preoperatively, but the rarer subtypes such as ours are more difficult to visualize on imaging. In gastrectomy, it is both oncologically important and technically challenging to perform lymph node dissection around the pancreas. In this case with an especially proximal pancreas, a circular stapler was considered better suited for gastroduodenal anastomosis and required a broader field than that afforded by laparoscopy. A case of non-typical annular pancreas diagnosed during laparoscopic gastric surgery is described