RESUMEN
BACKGROUND: Transanal total mesorectal excision (TaTME) allows patients with ultralow rectal cancer to be treated with sphincter-saving surgery. However, accurate delineation of the distal resection margin (DRM), which is essential to achieve R0 resection for low rectal cancer in TaTME, is technically demanding. AIM: To assess the feasibility of optical biopsy using probe-based confocal laser endomicroscopy (pCLE) to select the DRM during TaTME for low rectal cancer. METHODS: A total of 43 consecutive patients who were diagnosed with low rectal cancer and scheduled for TaTME were prospectively enrolled from January 2019 to January 2021. pCLE was used to determine the distal edge of the tumor as well as the DRM during surgery. The final pathological report was used as the gold standard. The diagnostic accuracy of pCLE examination was calculated. RESULTS: A total of 86 pCLE videos of 43 patients were included in the analyses. The sensitivity, specificity and accuracy of real-time pCLE examination were 90.00% [95% confidence interval (CI): 76.34%-97.21%], 86.96% (95%CI: 73.74%-95.06%) and 88.37% (95%CI: 79.65%-94.28%), respectively. The accuracy of blinded pCLE reinterpretation was 86.05% (95%CI: 76.89%-92.58%). Furthermore, our results show satisfactory interobserver agreement (κ = 0.767, standard error = 0.069) for the detection of cancer tissue by pCLE. There were no positive DRMs (≤ 1 mm) in this study. The median DRM was 7 mm [interquartile range (IQR) = 5-10 mm]. The median Wexner score was 5 (IQR = 3-6) at 6 mo after stoma closure. CONCLUSION: Real-time in vivo pCLE examination is feasible and safe for selecting the DRM during TaTME for low rectal cancer (clinical trial registration number: NCT04016948).
RESUMEN
Although amylose as a naturally-occurring helical polysaccharide has been widely used for biomedical applications, few studies have dealt with its chemical modification for non-viral gene delivery. In this work, the click modification of amylose by poly(l-lysine) dendrons was carried out and then characterized by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction and elemental analyses. Such a modified polysaccharide exhibited excellent ability to condense plasmid pMSCV-GFP-PARK2 into compact and spherical nanoparticles. Moreover, it displayed much lower cytotoxicity when compared to branched polyethylenimine (bPEI, 25kDa), a commercially available gene vector. Similar to bPEI, it had a dose-dependent gene transfection activity in human embryonic kidney 293T cells, as observed by confocal laser scanning microscopy and flow cytometry. At each optimized N/P ratio, the percentage of transfected cells by this modified polysaccharide was found to be comparable to that by bPEI. Western blot and cell apoptosis analyses confirmed its effectiveness for the delivery of plasmid pMSCV-GFP-PARK2 to 293T cells.