An experimental study on the uniaxial tensile property of concrete exposed to the acid rain environment was carried out. Acid rain with pH level of 1.0 was deposed by the mixture of sulfate and nitric acid solution in the laboratory. Dumbbell-shaped concrete specimens were immersed in the simulated acid rain completely. After being exposed to the deposed mixture for a certain period, uniaxial tensile test was performed on the concrete specimens. The results indicate that elastic modulus, tensile strength, and peak strain have a slight increase at the initial corrosion stage, and with the extension of corrosion process, elastic modulus and tensile strength decrease gradually, while the peak strain still increases. It is found that the compressive strength is more sensitive than the tensile strength in aggressive environment. Based on the experimental results, an equation was proposed to describe the ascending branch of the stress-strain curve of the concrete corroded by acid rain.
Abstract While topotecan (TPT) is a chemotherapeutic drug in treating lung cancer, the development of TPT resistance in tumors reserves as a major obstacle to chemotherapeutic success. Therefore, a better understanding of the mechanisms of TPT resistance is critical. In this study, the first topotecan-resistant human non-small cell lung cancer (NSCLC) cell line, termed NCI-H460/TPT10, was established from the parental NCI-H460 cell line. NCI-H460/TPT10 cells exhibited a 394.7-fold resistance to TPT, and cross-resistance to SN-38, mitoxantrone, and doxorubicin, compared to parental NCI-H460 cells. Overexpression of ABCG2 localized on the cell membrane, but not ABCB1 or ABCC1, was found in NCI-H460/TPT10 cells, indicating that ABCG2 was likely to be involved in TPT-resistance. This was confirmed by the abolishment of drug resistance in NCI-H460/TPT10 cells after ABCG2 knockout. Moreover, the involvement of functional ABCG2 as a drug efflux pump conferring multidrug resistance (MDR) was indicated by low intracellular accumulation of TPT in NCI-H460/TPT10 cells, and the reversal effects by ABCG2 inhibitor Ko143 and cabozantinib. The NCI-H460/TPT10 and its parental cell line were further used to establish in vivo tumor xenograft mouse models, which verified their capability to serve as clinically relevant models for drug screening and the development of targeted strategies to overcome ABCG2-mediated MDR in NSCLC. Citation Format: Qiu-Xu Teng, Zi-Ning Lei, Wei Zhang, Ying-Fang Fan, Jing-Quan Wang, Chao-Yun Cai, Dong-Hua Yang, John Wurpel, Zhe-Sheng Chen. Establishment and characterization of a topotecan resistant lung cancer NCI H460/TPT10 cell line and a tumor xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1095.
Objective To investigate the inhibitory effect of RNAi targeting HER2 on the proliferation of human colorectal cancer cells in vitro. Methods Human colorectal cancer HT-29 cells were transfected with plasmid expressing shRNA-HER2 by LipofectamineTM2000. The mRNA level and expression of HER2 in HT29 cells of each group were detected using semi-quantitive reverse transcription-polymerase chain reaction(RT-PCR) and Western blot,respectively. Inhibitory effect on proliferation of each group was measured by MTT assay. Results Plasmid mediated shRNA-HER2 can depress both transcriptional and translational level of HER2 in HT29 cells in vitro. Compared with control the proliferation of HT-29 cells was inhibited by shRNA-HER2 (P0.01). Conclusion Plasmid mediated shRNA-HER2 can inhibit the proliferation of HT-29 cells by reducing the HER2 gene expression in vitro.
Pancreatic cancer is malignant with a poor prognosis,and its incidence is rising worldwide in recent years.Multiple slices spiral computed tomography and computed angiography are the first choice for the diagnosis of pancreatic cancer,while misdiagnosis of pancreatic cancer still exists.From August 2009 to October 2011,80 patients with pancreatic or periampullary cancer were diagnosed using the medical image three dimensional visualization system (MI-3DVS).The threedimensional models of the liver,pancreas,vascular system and tumors were reconstructed successfully based on the 64-slice spiral computed tomography data.According to the analysis of the three dimensional models,4 patients underwent standard pancreaticoduodenectomy,1 received palliative surgery.MI3DVS plays an important role in the diagnosis and assessement of resectability of pancreatic and periampullary cancer.
Key words:
Pancreatic neoplasms ; Three-dimensional imaging; Resectability
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