MiR-21/RASA1 axis affects malignancy of colon cancer cells via RAS pathways

AIM:To determine how the oncogene mi R-21 regulates the RAS signaling pathways and affects colon cancer cell behaviors.METHODS:RAS p21 GTPase activating protein 1(RASA1) protein expression in six colon cancer cell lines was assessed by Western blot.Colon cancer RKO cells were chosen for transfection because they are KRAS wild type colon cancer cells whose RASA1 expression is significantly decreased.RKO cells were transfected with vectors overexpressing or downregulating either mi R-21 or RASA1.Furthermore,a luciferase reporter assay was used to determine whether RASA1 is a gene target of mi R-21.Then,changes in m RNA and protein levels of RASA1,RASGTP,and other components of the RAS signaling pathways were assessed in transfected RKO cells by real-time quantitative reverse transcription-polymerase chain reaction,Western blot and immunoprecipitation.Finally,cell proliferation,apoptosis,invasion,and tumorformation ability w ere assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide dye assay,flow cytometry,transwell assay,and animal experiment,respectively.RESULTS:RASA1 protein levels were significantly decreased in RKO cells compared with the other 5 colon cancer cell lines,and RASA1 was confirmed as a target gene of mi R-21.Interestingly,RASA1 m RNA and protein levels in pre-mi R-21-LV(up-regulation of mi R-21) cells were lower than those in anti-mi R-21-LV(down-regulation of mi R-21) cells(P < 0.05).In addition,pre-mi R-21-LV or si RASA1(down-regulation of RASA1) cells showed higher cell proliferation,reduced apoptosis,increased expression of RAS-GTP,p-AKT,Raf-1,KRAS,and p-ERK1/2,and higher invasion and tumor formation ability,compared with control,antimi R-21-LV or pc DNA3.1-RASA1(up-regulation of RASA1) cells(P < 0.05).CONCLUSION:RASA1 is a target gene of mi R-21,which promotes malignant behaviors of RKO cells through regulation of RASA1 expression.

微粒皮移植联合医用自凝集水凝胶修复家兔全层皮肤缺损的实验研究

目的评价自凝集水凝胶(医用可注射聚羧甲基葡萄糖胺凝胶)的皮内刺激反应,以及该材料与微粒皮移植联用对全层皮肤缺损的疗效。方法依据国家标准GB/T 16886.10—2005,对该材料进行皮内刺激反应安全性评价。麻醉家兔背部,切除3.5 cm×3.5 cm 全层皮肤。切下的皮肤裁剪成1 mm×1 mm 的微粒皮,将微粒皮在创面上摆放,滴洒水凝胶原液于创面。通过凝胶自凝完成微粒皮固定,用制备好的异体兔脱细胞真皮紧密覆盖创面、缝合。观察4 周,修复创面做病理观察。结果自凝集水凝胶无潜在的皮内刺激。凝胶联合微粒皮移植术4 周后伤口完全愈合且有毛发生长,病理切片可见皮肤创面修复,炎症细胞浸润较轻。结论自凝集水凝胶对局部皮肤组织无刺激。凝胶联合微粒皮移植可促使创面皮肤组织的修复再生。

成都和绵阳地区青少年近视患病率及影响因素分析

目的:调查四川省成都市和绵阳市6~18岁青少年近视情况及相关影响因素。方法:于2017-10/2018-05采用横断面分层整群随机抽样抽取成都市和绵阳市6~18岁在校学生4 071名,进行眼部检查和相关问卷调查。结果:本研究实际受检学生3 857名(94.74%),平均年龄11.86±3.43岁,近视和高度近视患病率分别为61.21%和3.89%;6岁和18岁受检者中近视发病率分别为12.05%和86.15%。裸眼视力和日常生活视力较好眼视力≤4.7者分别占42.88%和12.37%;戴镜率为48.07%。多因素Logistic回归分析结果表明,户外活动是近视的保护因素,而年龄、父母近视、近距离用眼、使用电子设备是近视的危险因素。结论:成都和绵阳地区青少年视力低下主要原因是近视,且随着年龄的增加,近视患病率呈逐渐增高趋势,其与年龄、父母近视、近距离用眼、使用电子设备、户外活动相关。

Decreased expression of DAB2IP in pancreatic cancer with wild-type KRAS

BACKGROUND: KRAS mutation plays an important role in the pathogenesis of pancreatic cancer. However, the role of wild-type KRAS in the progression of pancreatic cancer remains unknown. The present study was to investigate the expression of the Ras GTPase activating protein (DAB2IP) in pancreatic cancer and its clinical significance. METHODS: The expression of DAB2IP in pancreatic cancer cell lines and normal human pancreatic ductal epithelial cells was analyzed by Western blotting and realtime quantitative reverse transcription-PCR (qRT-PCR). The KRAS mutational types of pancreatic cancer tissues obtained from pancreatic cancer patients (n=20) were also analyzed. Subsequently, DAB2IP expression was detected in pancreatic cancer tissues, adjacent and normal pancreatic tissues (n=2) by immunohistochemistry, and the relationship between DAB2IP expression and the clinical characteristics of patients was evaluated. RESULTS: Western blotting and qRT-PCR results showed that DAB2IP expression in pancreatic cancer cells with wild-type KRAS was lower than that in those with mutation-type KRAS and normal human pancreatic ductal epithelial cells (P【0.05). Immunohistochemistry showed that DAB2IP expression was lower in pancreatic cancer tissues than that in adjacent and normal pancreatic tissues (Z=-4.000, P=0.000). DAB2IP expression was lower in pancreatic cancer patients with the wild-type KRAS gene than that in those with KRAS mutations (WilcoxonW=35.000, P=0.042). Furthermore,DAB2IP expression in patients with perineurial invasion was lower than that in those without invasion (WilcoxonW=71.500, P=0.028). DAB2IP expression was lower in patients with more advanced stage than that in those with early clinical stage (WilcoxonW=54.000, P=0.002). CONCLUSIONS: DAB2IP expression was reduced in patients with pancreatic cancer compared with those with no cancer. DAB2IP expression was correlated with the KRAS gene, perineurial invasion and clinical stage of the disease. Our data indicated that DAP2IP expression can be used as a potential prognostic indicator and a promising molecular target for therapeutic intervention in patients with pancreatic cancer.

SK channels modulate the excitability and firing precision of projection neurons in the robust nucleus of the arcopallium in adult male zebra finches

Objective Motor control is encoded by neuronal activity. Small conductance Ca2＋-activated K＋ channels （SK channels） maintain the regularity and precision of firing by contributing to the afterhyperpolarization （AHP） of the action potential in mammals. However, it is not clear how SK channels regulate the output of the vocal motor system in songbirds. The premotor robust nucleus of the arcopallium （RA） in the zebra finch is responsible for the output of song information. The temporal pattern of spike bursts in RA projection neurons is associated with the timing of the acoustic features of birdsong. Methods The firing properties of RA projection neurons were analyzed using patch clamp whole-cell and cell-attached recording techniques. Results SK channel blockade by apamin decreased the AHP amplitude and increased the evoked firing rate in RA projection neurons. It also caused reductions in the regularity and precision of firing. RA projection neurons displayed regular spontaneous action potentials, while apamin caused irregular spontaneous firing but had no effect on the firing rate. In the absence of synaptic inputs, RA projection neurons still had spontaneous firing, and apamin had an evident effect on the firing rate, but caused no significant change in the firing regularity, compared with apamin application in the presence of synaptic inputs. Conclusion SK channels contribute to the maintenance of firing regularity in RA projection neurons which requires synaptic activity, and consequently ensures the precision of song encoding.

Facile synthesis and superior photocatalytic and electrocatalytic performances of porous B-doped g-C_3N_4 nanosheets

As a low-cost visible-light-driven metal-free catalyst, graphitic carbon nitride(g-CN) has attracted increasing attention due to its wide applications for solar energy conversion, environmental purification,and organic photosynthesis. In particular, the catalytic performance of g-CNcan be easily modulated by modifying morphology, doping, and copolymerization. Simultaneous optimization, however, has little been achieved. Herein, a facile one-pot strategy is developed to synthesize porous B-doped g-CNnanosheets by using HBOand urea as the precursor during thermal polymerization. The resultant B-doped g-CNnanosheets retain the original framework of bulk g-CN, while induce prominently enhanced visible light harvesting and narrowing band gap by 0.32 eV compared to pure g-CN. Moreover, the adsorption capacity and photodegradation kinetics of methylene blue(MB) under visible light irradiation over B-doped g-CNnanosheets can be improved by 20.5 and 17 times, respectively. The synthesized porous B-doped g-CNnanosheets also exhibit higher activities than pure g-CNas bifunctional electrocatalyst for both oxygen evolution reaction(OER) and oxygen reduction reaction(ORR). The enhanced catalyst performance of porous B-doped g-CNnanosheets stems from the strong synergistic effect originating from the larger exposed active sites generated by the exfoliation of g-CNinto nanosheets and the porous structure, as well as the better conductivity owing to B-doping. This work provides a simple, effective, and robust method for the synthesis of g-CN-based nanomaterial with superior properties to meet the needs of various applications.

Heat transfer performance of porous titanium

Porous titanium fibre materials with different structural parameters were prepared by vacu- um sintering method. The thickness, porosity and wire diameter of prepared materials were investigated to understand the effects of structural parameters on pool heat transmission performance of titanium fibre porous material. As a result, better heat transfer performance is obtained when overheating is less than 10 ℃. In addition, when the wire diameter is smal- ler, the heat transfer is better. However, when superheating is above 10 ℃, heat transfer performance can be improved by increasing the wire diameter. Moreover, thickness influ- ences the superficial area of the prepared material and affects the thermal resistance when bubbles move inside the material; superficial area and thermal resistance are the two key factors that jointly impact the heat transfer in relation to the thickness of the materials. Ex- perimental results also show that the materials of 3 mm in thickness exhibit the best per formance for heat transmission. Furthermore, changes in porosity affect the nucleation site density and the resistance to bubble detachment; however, the nucleation site density and the resistance to bubble detachment conflict with each other. In summary, the titanium fi- bre porous material with a 50% porosity exhibits suitable heat transfer performance.