Downregulation of DEK induces cell apoptosis via inhibition of NF-κB signaling pathway in gastric carcinoma SGC-7901 cells

AIM: To investigate the effect of DEK downregulation on the apoptosis of gastric carcinoma SGC-7901 cells, and to explore its associations with NF-κB signaling pathway and apoptosis related proteins. METHODS: SGC-7901 cells with different treatments were divided into 3 groups including untreated group, control siRNA group and DEK siRNA group. The expression of DEK at mRNA and protein levels in the SGC-7901 cells was detected by real-time PCR and Western blot. The cell apoptosis was examined by flow cytometry. Furthermore, the activities of caspase-3 and caspase-9 in the SGC-7901 cells were investigated by Caspase-Glo^®-3/9 kit. Finally, the expression of key regulatory protein p65 of NF-κB signaling pathway and apoptosis-related proteins Bcl-2 and Bax in the SGC-7901 cells was investigated by Western blot. RESULTS: Compared with untreated group and control siRNA group, the expression of DEK at mRNA and protein levels was significantly downregulated in DEK siRNA group (P<0.05). In addition, the ratios of early phase apoptosis and total apoptosis in DEK siRNA group were markedly higher than those in untreated group and control siRNA group (P<0.05). Most notably, the decrease in p65 and Bcl-2 proteins, increase in Bax protein and the increases of caspase-3 and caspase-9 activities were observed in DEK siRNA group. CONCLUSION: Downregulation of DEK mediates cell apoptosis of gastric carcinoma may be tightly associated with NF-κB signaling pathway.     

Oxidative stress-activated JNK-MAPK signaling pathway is involved in fluctuant high glucose-induced injury of hepatocytes

AIM: To explore the mechanisms of fluctuant high blood glucose-induced apoptosis of hepatocytes. METHODS: SD rats were randomly divided into normal control group (N), stable high blood glucose group (S), fluctuant high blood glucose group (F) and insulin group (I). Diabetic rats were induced by intraperitoneal injection of streptozotocin (65 mg/kg), and the fluctuant high blood glucose animal model was induced by intraperitoneal injection of ordinary insulin and glucose at different time points every day. The blood glucose fluctuation patterns of the animals in F group within 12 weeks were similar every day and no significant difference of the HbA1c concentration was observed compared with S group, indicating that the fluctuant hyperglycemia was successfully established in F group. The activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the content of malondialdehyde (MDA) and nitric oxide (NO) in the homogenate of the liver tissues were detected by colorimetry. The mRNA and protein levels of JNK, p-JNK, Bax and Bcl-2 were examined by RT-PCR and Western blot. RESULTS: After 12 weeks, the increases in the intakes of food and water, the urine output, and the abnormal liver function were observed in S group, I group and F group. Compared with N group, the MDA level was increased, the content of NO and the activity of SOD and GSH-Px were decreased, and up-regulation of JNK mRNA and p-JNK and Bax proteins, and down-regulation of Bcl-2 were also found in S group, I group and F group. The above effects were more obviously showed in F group. CONCLUSION: Oxidative stress activates JNK-MAPK signaling pathway, which is involved in fluctuant high glucose-induced apoptosis of hepatocytes.     

Protective effect of chrysin on mice with insulin resistance

AIM: To explore the effects of chrysin on insulin resistance (IRe) in a mouse model. METHODS: Male C57 mice were randomly divided into control group, IRe group, low-dose chrysin group (IRe+chrysin-low) and high-dose chrysin group (IRe+chrysin-high). After 24 weeks, the body weight, liver index and fat mass in all mice were detected. The blood glucose, insulin level and HOMA-IR were measured to determine the changes of the insulin resistance in the animals. The oxidative stress (SOD, GSH-Px and MDA) was also measured. The mRNA expression of insulin signaling pathway molecules (IR, IRS1, IRS2, Glut2 and Glut4) and inflammatory factors (TNF-α, IL-1β, IL-6 and NF-κB) was analyzed by real-time PCR. The protein levels of IRS1 and p65, and their phosphorylation were detected by Western blot. RESULTS: After 24-week intervention, the indicators in IRe group were higher than those in control group, including body fat deposition, serum glucose, serum insulin, HOMA-IR and liver oxidative stress (P<0.01), indicating that the model of insulin resistance was successfully established. Low dose and high dose of chrysin decreased the body weight, serum glucose, serum insulin and HOMA-IR in the IRe mice (P<0.05). The liver oxidative stress was also reduced in both groups (P<0.05). However, no statistical difference of the indexes between IRe+chrysin-low group and IRe+chrysin-high group was observed. Chrysin upregulated the mRNA expression of IR, IRS1, IRS2, Glut2 and Glut4 (P<0.05), and down-regulated the mRNA expression of various inflammatory factors. The inhibitory effect of chrysin on the mRNA expression of NF-κB was observed (P<0.05), especially in high dose group (P<0.05). It was confirmed that the effect of chrysin on liver IRe was related with the increase in the p-IRS1 levels and decrease in the p-p65 levels by Western blot. CONCLUSION: Chrysin inhibits obesity, hyperglycemia and hyperinsulinemia, and relieves insulin resistance and oxidative stress, which might be closely related to the regulation of insulin signaling pathway and the inhibition of inflammatory factor expression.     

Expression of Jagged2/Notch3 signaling molecules in pulmonary hypertensive rats induced by monocrotaline

AIM: To study the expression of Jagged2/Notch3 signaling molecules in pulmonary vascular wall of pulmonary hypertensive rats induced by monocrotaline. METHODS: SD rats were randomly divided into normal control group (C group,n=15), solvent control group (S group,n=15) and monocrotaline model groups (M group,n=15). The model of pulmonary hypertension was established by a single subcutaneous injection of monocrotaline (50 mg/kg). The rats in S group were given a single subcutaneous injection of the same dose of solvent. After 4 weeks, the pulmonary vascular remodeling was assessed by HE staining, and the mean pulmonary artery pressure (mPAP) and right ventricular systolic pressure (RVSP) were determined by right heart catheterization. The expression of Jagged2/Notch3/Hes5 molecules in the pulmonary vascular wall was detected by immunohistochemical method and real-time PCR. RESULTS: Compared with S group and C group, the percentage of medial wall thickness of smaller arteries in model group increased significantly (P<0.01). The levels of mPAP and RVSP in M group were significantly higher than those in S group and C groups (P<0.01). The results of real-time PCR showed that the expression of Jagged2, Notch3 and Hes5 was significantly increased in M group compared with S group and C group. The data from immunohistochemical detection indicated that Jagged2 mainly expressed in the intima of small lung artery, Notch3 and Hes5 mainly expressed in the medial smooth muscle cells. Compared with S group and C group, the expression of Jagged2 and Notch3 was significantly increased in the lung small arteries of M group. CONCLUSION: The activation of Jagged2/Notch3 signaling pathway might play an important role in the formation of pulmonary hypertension.     

A Study Transient on Predictive Calculation Method of on Underground Ventilation Network

The authors developed a computer program of transient predictive calculation method on underground ventilation network. The program approximated a field data set of seasonal cyclic changes of air Temperature and humidity at the inlet to the sine curves, and included sensible heat conduction from rock to air current. The temperature of rock around and airway was calculated by finite difference method. The prediction method can be used to calculate the variation of flow rates, temperatures and humidities of air flow in the airways along underground network.     

日光温室番茄植株与环境传热研究

为了解植物体温度变化的原因，用热电偶测温仪和Li-cor的自动气象站测定日光温室番茄茎内和果实内部瞬态传导传热量的日变化规律，分析了茎内部传导传热量的趋势。测定了茎气温差，并根据生物传热学理论，估算了番茄植株与空气间的对流热交换量。结果表明，果实表面与中心存在温差，且有明显的日变化。果实瞬态传导传热量最大值为1.29 W，相当于晴天中午温室内太阳辐射的0.2%。不同天气条件下植株与环境对流传热有相同的日变化趋势，但白天与夜间不同。夜间失热，揭苫后失热增大，并持续到整个上午，10∶30失热量最大，达到-18.9 W/m²。下午至傍晚对流传热为得到热量，13∶30时最高，达到34.9 W/m²，这时正是一天中最高气温发生的时间。阴天对流传热日变化幅度明显减少。多云天气介于晴天与阴天的变幅之间，波动较明显。植株与环境间对流传热量比植株内部传导传热量大。     

玉米热风干燥中对流换热系数和当量导热系数的确定

以玉米作为热风干燥物料，在垂直热吹风干燥实验中，建立了干燥速率与对流换热系数的关系式。提出了由干燥速率来确定热风与玉米的对流换热系数，进而求取厚层玉米当量导热系数的实验方法     

胚胎干细胞诱导分化研究进展

哺乳动物胚胎干细胞一般可从胚胎囊胚内细胞团分离得到 ,具有在体外保持不分化的无限增殖能力 ,在合适的培养条件下 ,胚胎干细胞可定向诱导分化形成多种细胞类型。人们对胚胎干细胞进行体外培养与定向分化可以得到大量同源细胞 ,以应用于患疾病的细胞或器官移植治疗等研究。文章概述了胚胎干细胞增殖与分化的信号调节机制、诱导分化方法 ,国内外研究概况及展望 4个方面的内容     

飞秒激光微加工中热熔化与热传递现象研究

对飞秒激光能量密度为0.108~28.68J/cm2范围内加工的硅孔表面形貌尺寸进行分析,同时对热传递现象进行研究。理论分析了飞秒激光加工区域热传导时间及温度分布,并将其与实验测量值进行对比,验证了热影响的存在。通过理论与实验分析说明了在高能量飞秒激光加工中热传递现象不可避免,并获得了较好的孔加工质量的激光能量合理参数。     

多路径下桃园射频信号传输特性

为解决无线传感器网络在桃园中的快速部署问题,该文研究了2.4 GHz无线射频信号在桃园中的传播特性。依据角度选取4条传输路径,在3种(0.5、1.5、2.5 m)典型的天线高度,同时测量丢包率和路径损耗情况,分析表明两者具有明显的相关性,天线高度和通信距离是路径损耗的主要影响因素。在天线高度为0.5和1.5 m时,可靠传输距离为6个行距(27 m);在天线高度为2.5 m时,可靠传输距离大于14个行距(63 m),因此冠层顶部为布设天线的最佳位置。对路径损耗数据进行回归分析,发现其在每种天线高度,每条传输路径下对数模型最适合作为路径损耗模型,模型的R2最大为0.945,最小为0.732。为研究节点部署于桃园任意位置时的路径损耗情况,便于节点快速灵活地部署,在3种天线高度下对路径损耗数据进行对数回归分析,R2最大为0.976,最小为0.939。最后对2组模型进行了验证,表明模型可以预测射频信号在桃园中的路径损耗情况,该文研究结果为无线传感器网络在桃园中的部署提供了参考。