Follow‐up on the γ‐glutamyl transpeptidase in patients with severe dysplasia in an area of high incidence of esophageal cancer

OBJECTIVE: To investigate the clinical value of cytological γ‐glutamyl transpeptidase (γ‐GT) staining in the reduction of the morbidity and mortality of esophageal cancer in an area of China that has a high incidence of esophageal cancer. METHODS: The results of pathology, cytological examination with γ‐GT staining in 451 patients with severe dysplasia were analyzed and followed‐up for 3 years. RESULTS: At the 1‐year follow‐up, 17 of 231 patients with positive γ‐GT staining (7.4%) had developed esophageal cancer, but no cancer was detected in 95 patients with negative γ‐GT staining. Among 215 patients who were followed‐up for 3 years, the risk of developing cancer in γ‐GT staining positive patients with grade I or II severe dysplasia was 5.7% and 14.3%, respectively. However, esophageal cancer was not found in patients with negative γ‐GT staining or in patients with positive γ‐GT staining who were younger than 40 years. CONCLUSIONS: These findings suggest that γ‐GT staining can be used as a cancer risk marker of esophageal epithelial dysplasia. Esophageal dysplasia needs to be further categorized according to γ‐GT staining for esophageal cancer prevention, and intervention is required for γ‐GT staining positive patients with severe dysplasia in order to increase the cost–benefit ratio of esophageal cancer prevention.     

Study of the voxel-based specific regional analysis system for Alzheimer's disease imaging sequence after magnetic resonance apparatus replacement

In our institute, an MR apparatus, MAGNETOM VISION (Siemens) was replaced by ECHELON Vega (HITACHI). Z-score data acquired by MPRAGE (VISION) was compared with those by radio frequency-spoiled steady-state acquisition with rewinded gradient echo (RSSG) and gradient echo inversion recovery (GEIR) (ECHELON). For this study, ten normal volunteers were recruited and their data ware obtained within two months using both apparatuses. In addition, the difference of the contrasts of the images of these apparatuses was compared. There was a significant difference between Z-scores of MPRAGE and RSSG while there was no difference between MPRAGE and GEIR. As for the contrast, data of MPRAGE were similar to those of GEIR. To compare Z-scores acquired with MAGNTOM VISION (Siemens), it seems appropriate to use GEIR in ECHELON Vega.     

Effects of electrical-hydrothermal aging degradation on dielectric and trap properties of high temperature vulcanized silicone rubber materials

In this paper, a new aging platform combined the high voltage electric field and the hydrothermal environment was built. To investigate the aging mechanism, physicochemical, dielectric and trap properties of HTV SR before and after electrical-hydrothermal aging for 24 days were discussed. The results indicated that, compared with hydrothermal aging, more cracks and holes appeared on the surface of HTV SR after electrical-hydrothermal aging, and the content of flame retardant decreased significantly. Due to the main chain and side chain scission of PDMS, lots of low weight molecular (LWM) substances and free radicals were produced. And the tensile strength and elongation at break significantly decreased. Various physical and chemical defects appeared in the HTV SR specimen in the process of electrical-hydrothermal degradation, as a result of which, the dielectric constant significantly increased and the peak trap density increased by about 2.5 times compared to the virgin sample. The increase in trap density in turn accelerated the charge accumulation and enhanced the breakdown probability, resulting in the electric field strength decrease from 21.8 kV mm⁻¹ to 16.1 kV mm⁻¹ and severe degradation of HTV SR.

In this paper, a new aging platform combined the high voltage electric field and the hydrothermal environment was built.