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Promoting Evidence-Based Practice in Nursing

In Vitro Radiosensitivity Study of Head and Neck Squamous Carcinoma Cell SCCⅦ

目的：研究小鼠头颈鳞癌细胞株SCCⅦ体外放射敏感性，并探讨其与细胞周期阻滞的可能关系。方法：利用细胞克隆形成试验及MTT法检测SCCⅦ细胞受X射线照射后细胞存活能力及细胞生长趋势的变化，通过流式细胞学检测X射线照射后细胞周期分布的变化。结果：相同剂量照射后的SCCⅦ细胞存活分数高于Hela细胞（Plt;0.05）；4 Gy照射后的SCCⅦ细胞在96 h内细胞生长速度仍高于Hela细胞（Plt;0.05）；4 Gy照射后SCCⅦ细胞G1期和G2期细胞比例明显升高（Plt;0.05）。结论：SCCⅦ细胞对放射线不敏感性，放射线导致的细胞周期阻滞是SCCⅦ细胞放射抵抗的可能原因之一

Effect of RNAi Silencing of The DLL4 Gene for Inducing Apoptosis and Chemosensitivity to Docetaxel of Human Breast Cancer Cells

Objective　To explore effect of DLL4 gene in MCF-7 cells of human breast cancer which was inhibitted by short hair in RNA （shRNA） on inducing apoptosis and chemosensitivity to docetaxel. Methods　Specific shRNA was designed in accordance with DLL4 gene and transfected into MCF-7 cells of human breast cancer with liposomal （Lip-shRNA group）， MCF-7 cells transfected with only liposomal as Lip group， and control group without any treatment. Expressions of DLL4 protein in 3 groups were detected by immunohistochemical method， apoptosis and cell cycle distribution were examined by flow cytometry （FCM）. Proliferations and sensitivity of MCF-7 cells to docetaxel in 3 groups were determined by methylthiazoyl-tetrazolium bromide （MTT）. Results　The averages optical density value and rate of positive area of Lip-shRNA group were significantly lower than that of other 2 groups （P＜0.01）. The levels of A value at 24h， 48h， and 72h in Lip-shRNA group were significantly lower than that of other 2 groups （P＜0.01）. Rates of cell apoptosis at 24h， 48h， 72h and 96 h in Lip-shRNA group were significantly higher than that of other 2 goups （P＜0.05），and ratio of G2/M was higher too （P＜0.05）. IC50 of Lip-shRNA group to docetaxel was significantly lower than that of other 2 groups （P＜0.05）. Conclusions　The RNA interference technology can effectively block the expression of DLL4 gene. Inhibition of DLL4/Notch signaling pathway can lead to proliferation inhibition of cancer cell and a concomitant increase in cells undergoing apoptosis， and can enhance the cell sensitivity to docetaxel. DLL4 may be an important target for therapeutic approach of breast cancer.

Sensitivity Test of Chemotherapy on Human Colorectal Cancer in Vivo

Objective　To investigate the sensitivity of 5 kinds of chemotherapeutic drugs on human colorectal cancer in vivo. Methods　Xenografts in nude mice were set up by tumor tissues from 9 patients with colorectal cancer and nude mice were divided into 6 groups randomly， receiving saline （control group）， 5-fluorouracil （5-FU group）， doxorubicin（ADM group）， mitomycin （MMC group）， oxaliplatin （LOHP group）， and irinotecan （CPT-11 group）， respectively. The inhibitive rates （IR） of xenografts in 5 groups for each patient were calculated. Results　The lowest and highest IR of 5 groups were 23.6% and 54.9% in 5-FU group， 23.7% and 69.5% in LOPH group， 23.6% and 82.6% in CPT-11group， 24.1% and 48.1% in MMC group， 5.8% and 20.7% in ADM group， respectively. The IR exceeded 40.0% in 7 patients of LOHP group， 6 patients of CPT-11 group， 4 patients of 5-FU group， and 1 patient of MMC group， respec-tively. Of 9 patients， the IR exceeded 40.0% to 3 kinds of drugs in 3 patients， to 2 kinds of drugs in 4 patients， the IR didn’t exceed 30.0% to 4 kinds of drug （IR was 82.6% to CPT-11） in 1 patient， and the IR didn’t exceed 31.0% to all 5 kinds of drugs in 1 patient. There were statistical differences on the IR of 5 kinds of drugs （H=24.061 2， P=0.000 1）. IR of ADM group was statistical lower than 5-FU group， MMC group， LOHP group， and CPT-11 group （P＜0.05），but there were no statistical differences between 5-FU group， MMC group， LOHP group， and CPT-11 group （P＞0.05）. Conclusions　The xenografts from same patient have different sensitivity to different chemotherapy drugs， and the same chemotherapy drug corresponds to different IR in different patients. The IR of LOHP and CPT-11 are the highest， following by 5-FU and MMC.

Research Progress of Preoperative Radiotherapy for Rectal Cancer

Objective　To summarize the current advancement of preoperative radiotherapy for rectal cancer. Methods　Relevant literatures about current advancement of preoperative radiotherapy for rectal cancer published domesticly and abroad recently were collected and reviewed. Results　The lower local recurrence rate and longer disease-free survival time were observed in preoperative radiotherapy， compared with postoperative radiotherapy for rectal cancer. The recurrence rate was higher in short-course radiotherapy， compared with conventionally radiotherapy for stageⅢrectal cancer， but there was no significant difference for stageⅡrectal cancer. The biology molecular such as p53， CEA， Cox-2， EGFR， and VEGF had shown to be radiosensitive. Conclusions　The proposal of preoperative radiotherapy for rectal cancer， could be prone to conventionally radiotherapy. There are more screening targets for preoperative radiotherapy in extensive exploration of diverse radiosensitivity. Biology molecular， developed gene expression profiling， and gene chips for rectal cancer may contribute to the individualization treatment.

Relationship of small airway function with airway sensitivity and reactivity

Objective To investigate the relationship of small airway function with airway sensitivity and reactivity and assess the factors influencingairway hyperresponsiveness (AHR).Methods Data of consecutive subjects with suspected asthma who had a≥20% reduction in FEV1 after ≤12.8 mmol/L cumulative doses of methacholine were analyzed from January 2005 to April 2006.Airway sensitivity was assessed by the cumulative dose of methacholine required to cause 20% reduction in FEV1 (PD20).Airway reactivity was analyzed using the slope of the dose-response curve (DRS).The DRS was defined as the reduction in FEV1 from baseline after the final dose of methacholine inhaled divided by the cumulative dose inhaled.Because of their highly skewed distribution，DRS was logarithmically transformed (log10) for all analysis.Results A total of 184 consecutive subjects aged 16 to 80 years was enrolled.There were 70 male (38.0%) and 114 female (62.0%) subjects.Subjects with higher airway sensitivity，indicated by lower PD20，also had a lower Vmax50% and Vmax25%，and vise versa.PD20 was negatively correlated wit log10DRS (r=-0.874，Plt;0.01).In a simple linear regression model，log10DNS was significantly correlated with FEV1%，Vmax50% or Vmax25% respectively (the determinant r2 were 0.062，0.097 and 0.085，respectively，all Plt;0.01).In a multiple linear regression model that included age，height，and percentage of predicted FEV1，Vmax50% and Vmax25% accounted for 3.9% and 2.6%，respectively，of variability in airway reactivity.The association between Vmax50% and log10DNS was significant in both male and female subjects.The r2 was higher in male subjects.The subjects were divided into three age groups and the association between Vmax50% or Vmax25% and log10DNS was higher in female than in male for age≤25 years，higher in male than in female for 25 -45 years.No association was found for agegt;45 years in both males and females.Conclusions Impaired small airway function is associated with higher airway sensitivity and reactivity to methacholine in subjects with suspected asthma.

Ku80 siRNA Silences Ku80 Expression and Enhances Radiosensitivity of A549 Lung Cancer Cells

Objective To investigate the radiation-sensitizing effects of Ku80 silencing by siRNA interference for A549 lung cancer cells. Methods The sequences of Ku80 siRNA and negative siRNA were chemically synthesized and transfected into A549 lung cancer cells by lipofectamine. RT-PCR and Western bolt analysis were used to determine Ku80 gene expression. The transfected cells in culture dishes were irradiated with X ray at doses of 2 Gy, 4 Gy, 6 Gy, 8 Gy, 10 Gy, respectively. Once all treatments were completed, the cells were processed with the colony formation assay. Results RT-PCR detection showed that Ku80 mRNA levels in A549 lung cancer cells were reduced after transfected with Ku80 siRNA at 24 h, 48 h and 72 h time points. Western blot analysis showed that Ku80 protein content decreased at 48 h and 72 h time points compared with the control group ( P lt; 0. 05 ) . Cloning formation assay indicated that radiosensitivity of A549 lung cancer cells was enhanced after transfected with Ku80 siRNA. Conclusion Ku80 siRNA can effectively inhibit Ku80 gene expression of A549 lung cancer cells, and therefore enhance its radiosensitivity.

The Role of Mitochondrial Adenosine Triphosphatesensitive Potassium Channel in Immature Myocardial Ischemic Preconditioning

Objective To investigate the role of mitochondrial adenosine triphosphatesensitive potassium channel(mitoKATP) in immature myocardial ischemic preconditioning, and to provide evidence for immature myocardial protection. Methods Langendorff isolated heart infused model was used in the experiment. Twentyfour rabbits (aged from 14 to 21 days) were randomly divided into 4 groups：ischemiareperfusion group（I/R group）, myocardial ischemic preconditioning group(E1 group), 5hydroxydecanoate(5-HD) group (E2 group) and Diazoxide (Diaz) group(E3 group). Hemodynamics recovery rate, myocardial water content(MWC), the leakage rates of serum creatine kinase and lactate dehydrogenase, adenosine triphosphate content, superoxide dismutase activity, malondialdehyde content, myocardial cell Ca2+ content and myocardial mitochondrial Ca2+ content, myocardial mitochondrial Ca2+-ATPase activity, the adenosine triphosphate(ATP) synthesizing ability of myocardial mitochondria were tested, and myocardial ultrastructure was observed via electron microscopy. Results The hemodynamics recovery rate, myocardial water content(P＜0.05), adenosine triphosphate content, superoxide dismutase activity, myocardial mitochondrial Ca2+-adenosine triphosphyatase(ATPase) activity and the ATP synthesizing ability of myocardial mitochondria of the rabbits in E1 and E3 group were significantly better than that in I/R group and E2 group(P＜0.05). Malondialdehyde content, the leakage rates of serum creatine kinase and lactate dehydrogenase, myocardial cell Ca2+ content and myocardial mitochondrial Ca2+ content of the rabbits in E1 group and E3 group were significantly lower than that in I/R group and E2 group (P＜0.05). The myocardial ultrastructure injury in E1 and E3 group were significantly reduced compared with that in I/R and E2 group. Conclusion Myocardial ischemic preconditioning has significant protective effects on immature myocardium. Its mechanism may be related to the activation of mitoKATP.

The Protective Effects of Ischemic Postconditioning on Ischemiareperfusion Myocardium and the Relationship with Mitochondrial Adenosine Triphosphate Sensitive K+ Channels

Objective To investigate the protective effects of ischemic postconditioning (IPo) on ischemiareperfusion (I/R) myocardium and the relationship with mitochondrial adenosine triphosphate (ATP) sensitive K+ channels (mitoKATP) and provide evidences to the development of druginduced postconditioning. Methods Langendorff models were established in 40 Wistar rats which were divided into 5 groups by random number table with 8 rats in each group. Normal control group(NC group): the rat hearts were continuously reperfused by KrebsHenseleit bicarbonate buffer (K-HB) for 100 min without any other treatment; I/R group: the rat hearts underwent a 40-min global ischemia followed by a 60-min reperfusion; IPo group: after a 40-min global ischemia, the process of 10-second reperfusion followed by a 10-second ischemia was repeated 6 times, then there was a continuous 58min reperfusion; 5-hydroxydecanoic acid(5-HD) group: after a 40min global ischemia, hearts with 5HD(100 μmol/L) K-HB were reperfused for 15min and then perfused without 5HD for 45min；IPo+5-HD group: after a 40-min global ischemia, the process that the isolated hearts with 5-HD(100 μmol/L) KHB were reperfused for 10second followed by a 10second ischemia was repeated 6 times, then the hearts with 5-HD(100 μmol/L) KHB were continuously [CM(159mm]perfused for 13-min followed by reperfusion without 5-HD(100 μmol/L) K-HB for 45-min. The cardiac function,coronary flow(CF), cardiac troponin I(cTnI) content in coronary effluent, the area of acute myocardial infarction (AMI) and myocardial ultrastructure were observed. Results Left ventricular developed pressure(74.3±3.3 mm Hg vs. 57.1±3.3 mm Hg,t=1300, P=0.000),+dp/dtmax(1 706.6±135.6 mm Hg/s vs. 1 313.3±96.2 mm Hg/s,t=6.28,P=0.000),－dp/dtmax(1 132.8±112.1 mm Hg/s vs. 575.7±67.7 mm Hg/s,t=13.48, P=0.000) and CF(6.49±0.30 ml/min vs. 3.70±0.24 ml/min,t=28.6,P=0.000) in IPo group were higher than those in I/R group. Left ventricular enddiastolic pressure(10.9±1.7mm Hg vs. 26.2±1.5 mm Hg,t=－19.21, P=0000)and cTnI content in coronary effluent (0.62±0.01 ng/ml vs. 0.71±0.01 ng/ml, t=-12.00,P=0.000) were lower than those in I/R group; the area of AMI decreased 20.8％ compared with that in I/R group (Plt;0.05). The myocardial protective effect in IPo+5HD group was similar with that in IPo group, but lower than that in IPo group. The electron microscope showed that IPo and IPo+5HD could reduce myocardial fiber damage and mitochondrial damage caused by I/R. Conclusion IPo can protect I/R myocardium, which is achieved mainly by activating mitoK-ATP channels. 

EFFECT OF HYDROSTATIC PRESSURE ON INTRACELLULAR FREE CALCIUM CONCENTRATION AND TRANSIENT RECEPTOR POTENTIAL VANILLOID EXPRESSION IN HUMAN BLADDER SMOOTH MUSCLE CELLS

Objective To explore the effect of hydrostatic pressure on intracellular free calcium concentration ([Ca2+]i) and the gene expression of transient receptor potential vanilloid (TRPV) in cultured human bladder smooth muscle cells (hb-SMCs), and to prel iminarily probe into the possible molecular mechanism of hb-SMCs prol iferation stimulated by hydrostatic pressure. Methods The passage 6-7 hb-SMCs were loaded with Ca2+ indicator Fluo-3/AM. When the hb-SMCs were under 0 cm H2O (1 cm H2O=0.098 kPa) (group A) or 200 cm H2O hydrostatic pressure for 30 minutes (group B) and then removing the 200 cm H2O hydrostatic pressure (group C), the [Ca2+]i was measured respectively by inverted laser anningconfocal microscope. When the hb-SMCs were given the 200 cm H2O hydrostatic pressure for 0 hour, 2 hours, 6 hours, 2 hours, and 24 hours, the mRNA expressions of TRPV1, TRPV2, and TRPV4 were detected by RT-PCR technique. Results The [Ca2+]i of group A, group B, and group C were (100.808 ± 1.724), (122.008 ± 1.575), and (99.918 ± 0.887) U, respectively; group B was significantly higher than groups A and C (P lt; 0.001). The [Ca2+]i of group C decreased to the base l ine level of group A after removing the pressure (t=0.919, P=0.394). The TRPV1, TRPV2, and TRPV4 genes expressed in hb-SMCs under 200 cm H2O hydrostatic pressure at 0 hour, 2 hours, 6 hours, 12 hours, and 24 hours, but the expressions had no obvious changes with time. There was no significant difference in the expressions of TRPV1, TRPV2, and TRPV4 among 3 groups (P gt; 0.05). Conclusion The [Ca2+]i of hb-SMCs increases significantly under high hydrostatic pressure. As possible genes in stretch-activated cation channel, the TRPV1, TRPV2, and TRPV4 express in hb-SMCs under 200 cm H2O hydrostatic pressure. It is possible that the mechanical pressure regulates the [Ca2+]i of hb-SMCs by opening the stretch-activated cation channel rather than up-regulating its expression.