胃癌干细胞在肿瘤侵袭转移及对血管形成的影响

背景:胃癌干细胞在新辅助化疗、常规治疗中发挥重要作用,与患者治疗后复发关系密切,但是该结论尚未得到证实。目的:观察胃癌干细胞在肿瘤侵袭转移中的作用及对血管形成能力的影响。方法:建立胃癌模型裸鼠,分离培养胃癌干细胞。将采集的胃癌干细胞分别进行细胞划痕实验、成环实验、细胞抑制率实验、细胞转移性实验及成瘤实验。结果与结论:(1)细胞形态:胃癌干细胞培养7 d后贴壁生长,贴壁细胞缺乏规律性,多为蝌蚪形;(2)划痕实验:划痕后0,24 h细胞划痕宽度差异有显著性意义(P<0.05);(3)成环实验:倒置显微镜观察显示,胃癌干细胞能形成环状;(4)细胞抑制率实验:奥沙利铂干预胃癌干细胞的半抑制浓度显著低于5-氟尿嘧啶(P<0.05);(5)胃癌肿瘤干细胞转移性实验:胃癌干细胞穿过基底膜细胞数显著高于细胞转移前(P<0.05);(6)成瘤实验:胃癌干细胞植入后胃癌组织质量显著重于普通胃癌裸鼠(P<0.05)。结果说明:胃癌干细胞在肿瘤侵袭、转移中发挥重要的作用,具备较强的血管形成能力。

Experimental Research on Flash Boiling Spray of Dimethyl Ether

The high-speed digital imaging technique is applied to observe the developing process of flash boiling spray of dimethyl ether at low ambient pressure, and the effects of nozzle opening pressure and nozzle hole diameter on the spray shape, spray tip penetration and spray angle during the injection are investigated. The experimental results show that the time when the vortex ring structure of flash boiling spray forms and its developing process are determined by the combined action of the bubble growth and breakup in the spray and the air drag on the leading end of spray; with the enhancement of nozzle opening pressure, the spray tip penetration increases and the spray angle decreases. The influence of nozzle hole diameter on the spray tip penetration is relatively complicated, the spray tip penetration is longer with a smaller nozzle hole diameter at the early stage of injection, while the situation is just opposite at the later stage of injection. This paper establishes that the variation of spray angle is consistent with that of nozzle hole diameter.