Aptamers from Cell-based Selection for Bioanalysis and Bioimaging / 分析化学

Aptamers are single-stranded oligonucleotides ( DNA or RNA ) selected through a technology termed "Systematic evolution of ligands by exponential enrichment" ( SELEX ) . In addition to high affinity and high specificity for their target molecules, aptamers have some advantages such as low molecular weight, easy synthesis, high chemical stability, low immunogenicity, and convenient modification. Based on the Cell-SELEX technique, a panel of aptamers which can specifically recognize target cell lines has been generated. By targeting specific membrane proteins in their native state, these aptamers can identify subtle molecular differences among different cell lines, thus have attracted a broad interest in biomedical research. In this review, we summarized the development of aptamers and their use in detection, profiling and imaging of tumor cells. Also, their perspectives were discussed.

Left atrial wall thickness: anatomic aspects relevant to catheter ablation of atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The success and complication rates of atrial fibrillation (AF) ablation may be related to regional differences in left atrial (LA) wall thickness. The purpose of this study was to investigate the transmural LA wall thickness in various regions.</p><p><b>METHODS</b>We measured LA wall thickness in 36 human heart specimens using calipers at three planes including left pulmonary veins (PVs) vestibule plane, right PVs vestibule plane and the middle plane between the two. In each plane, eight points were selected, including superior, middle and inferior levels at anterior and posterior wall, roof and bottom.</p><p><b>RESULTS</b>The anterior and posterior wall thickness displayed gradient from superior to inferior level (anterior wall: (2.73 ± 1.01) mm, (2.08 ± 0.91) mm and (1.54 ± 0.69) mm; posterior wall: (1.74 ± 0.68) mm, (1.48 ± 0.39) mm and (1.27 ± 0.42) mm). At the roof, LA wall thickness was thickest in middle plane ((2.01 ± 1.02) mm) and was thinnest in left PVs vestibule plane ((1.29 ± 0.41) mm). The posterior wall thickness in left PVs vestibule plane was thinner than in the other two planes (P < 0.05 - 0.001), and was thinner in right PVs vestibule plane than in middle plane (P < 0.01 - 0.001). Whereas in anterior wall, the wall thickness in left PVs vestibule plane was thicker than in middle and right PVs vestibule plane.</p><p><b>CONCLUSIONS</b>Significant variations exist for mean LA wall thickness at different regions which are often targeted during circumferential pulmonary venous ablation (CPVA). Appreciating these differences may have significant implications in catheter ablation of AF.</p>