The Wnt signaling pathway is essential for normal development and organogenesis. However, inappropriate activation of Wnt signaling, which results in the nuclear translocation of b-catenin, is associated with the development of various types of neoplasm. In this study, we investigated possible mutations in the genes for components of this pathway, namely, CTNNB1 (the gene for b-catenin), AXIN1, and APC, in adenoid cystic carcinoma, by PCR, analysis of single-strand conformational polymorphism, and sequencing. Among a total of 20 cases of adenoid cystic carcinoma, seven cases (35%) were associated with mutations in one or more of these three components. A mutation in CTNNB1 was detected in one case. Five cases, including the case with a mutation in CTNNB1, were associated with missense mutations in AXIN1. An aberration in the mutation cluster region of APC was detected in two cases. Mutations trended to be detected more frequently in adenoid cystic carcinoma with solid growth pattern than that with tubular and cribriform growth pattern. In the cases in which we detected mutations, it is possible that the presence of the abnormal products of the mutated genes resulted in the inappropriate activation of the Wnt signaling pathway to tumorigenesis and the growth of adenoid cystic carcinoma.
To investigate the possibility of an interaction between two ubiquitous human pathogens, Helicobacter pylori and Epstein-Barr virus (EBV), the effect of monochloramine (NH 2 Cl), locally produced by H. pylori infection, on gastric epithelium latently infected with EBV was examined, by assessing the induction of EBV lytic infection. AGS cells harbouring latently infected EBV were used as the indicator of lytic change caused by NH 2 Cl treatment. Lytic infection, determined by morphological change and EA-D antigen expression, occurred immediately after treatment with in vitro-synthesized NH 2 Cl. Analysis of EBV infection in human gastric tissue revealed that out of 48 H. pylori-positive patients, 24 were positive for EBER-1, and 18 and 13 were positive for EBNA1 and LMP-1 antigen, respectively. The results suggest that H. pylori-associated NH 2 Cl induces EBV lytic conversion in gastric epithelium latently infected with EBV.
Background
Press-fit and screw fixation are important technical factors to achieve initial stability of a cementless acetabular cup for good clinical results of total hip arthroplasty. However, how these factors affect one another in initial cup fixation remains unclear. Therefore, this study aimed to evaluate the mutual influence between press-fit and screw fixation on initial cup stability.MethodsFoam bone was subjected to exact hemispherical-shape machining to diameters of 48, 48.5 and 49 mm. A compressive force was applied to ensure seating of a 48-mm-diameter acetabular cup in the foam bone prior to testing. Screws were inserted in six different conditions and tightened in a radial direction at the same torque strength. Then, the socket was rotated with a twist-testing machine, and the torque value at the start of axial rotation between the socket and the foam bone was measured under each screw condition.ResultsThe torque values for the 48-mm-diameter reaming were >20 N m higher than those for the 48.5- and 49-mm-diameter reaming in each screw condition, indicating that press-fit fixation is stronger than screw fixation. Meanwhile, torque values for the 48.5- and 49-mm-diameter reaming tended to increase with increasing the number of screws.ConclusionsAccording to our experiment, press-fit fixation of a cementless acetabular cup achieved rigid stability. Although the supplemental screws increased stability of the implant under good press-fit conditions, they showed little impact on whole-cup stability. In the case of insufficient press-fit fixation, cup stability depends on screw stability and increasing the number of additional screws increases cup stability.
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