Long interspersed nuclear element-1 hypomethylation in cancer: biology and clinical applications

Epigenetic changes in long interspersed nuclear element-1s (LINE-1s or L1s) occur early during the process of carcinogenesis. A lower methylation level (hypomethylation) of LINE-1 is common in most cancers, and the methylation level is further decreased in more advanced cancers. Consequently, several previous studies have suggested the use of LINE-1 hypomethylation levels in cancer screening, risk assessment, tumor staging, and prognostic prediction. Epigenomic changes are complex, and global hypomethylation influences LINE-1s in a generalized fashion. However, the methylation levels of some loci are dependent on their locations. The consequences of LINE-1 hypomethylation are genomic instability and alteration of gene expression. There are several mechanisms that promote both of these consequences in cis. Therefore, the methylation levels of different sets of LINE-1s may represent certain phenotypes. Furthermore, the methylation levels of specific sets of LINE-1s may indicate carcinogenesis-dependent hypomethylation. LINE-1 methylation pattern analysis can classify LINE-1s into one of three classes based on the number of methylated CpG dinucleotides. These classes include hypermethylation, partial methylation, and hypomethylation. The number of partial and hypermethylated loci, but not hypomethylated LINE-1s, is different among normal cell types. Consequently, the number of hypomethylated loci is a more promising marker than methylation level in the detection of cancer DNA. Further genome-wide studies to measure the methylation level of each LINE-1 locus may improve PCR-based methylation analysis to allow for a more specific and sensitive detection of cancer DNA or for an analysis of certain cancer phenotypes

The UKCAT-12 study: educational attainment, aptitude test performance, demographic and socio-economic contextual factors as predictors of first year outcome in a cross-sectional collaborative study of 12 UK medical schools

Most UK medical schools use aptitude tests during student selection, but large-scale studies of predictive validity are rare. This study assesses the United Kingdom Clinical Aptitude Test (UKCAT), and its four sub-scales, along with measures of educational attainment, individual and contextual socio-economic background factors, as predictors of performance in the first year of medical school training

Dynamic analysis for clarifying occlusal force transmission during orthodontic archwire application: difference between ISW and stainless steel wire

The purpose of our study was to utilize the dynamic finite element analysis to clarify the difference between Improved Super-elastic Ti-Ni alloy Wire (ISW) and Stainless Steel Wire (SSW) on occlusal force transmission during orthodontic treatment. ABAQUS/Standard was used to analyze three finite models over a 30-ms period: ISW, SSW, and wireless models; which consisting of premolar, molar, periodontal ligament (PDL), and alveolar bone. Wire model was established by beam element. A Joint C, which exhibits viscoelasticity to buffer occlusal force, was applied between the wire and bracket. The load was applied on the occlusal surface. At load withdrawal point, the average amounts of von Mises stress on PDL in three models were of the same value. However as time progressed, the stress in wireless model became higher than ISW and SSW models. In contrast, as time progressed further, the stress in SSW model became higher than the other two models and maintained its higher level until the end of analysis. Results showed that high damping capacity of ISW had an ability to buffer the transmission of occlusal force to the PDL. Besides, the dynamic analysis demonstrated an advantage to investigate the stress alterative response between models versus time period