The present study is to elucidate the mechanisms underlying Gleevec-induced apoptosis of chronic myeloid leukemia (CML) K562 cells in vitro. The apoptotic cell death and cell cycle distribution after Gleevec treatment and the effect of PDCD4 siRNA on Gleevec-induced apoptosis of K562 cells were analyzed by flow cytometry. The effect of Gleevec on p-Crkl, caspase-3, PARP and PDCD4 protein levels, and the knockdown efficacy of PDCD4 siRNA were detected by Western blotting. The results showed that Gleevec dramatically suppressed the phosphorylation level of Crkl in a dose-dependent manner and induced significant apoptosis and G0/G1 cell cycle arrest of K562 cells in time- and dose-dependent manners. In addition, Gleevec activated caspase-3 and its downstream substrates PARP, and the caspase pan inhibitor Z-VAD-FMK (50 micromol x L(-1)) markedly reduced Gleevec-induced apoptosis from 47.97% +/- 10.56% to 31.05% +/- 9.206% (P < 0.05). Moreover, Gleevec significantly increased the protein expression of programmed cell death 4 (PDCD4). PDCD4 knockdown by siRNA reduced Gleevec-induced apoptosis from 46.97% +/- 14.32% to 42.8% +/- 11.43%. In summary, Gleevec induced apoptosis in K562 cells via caspase-3 activation.

Background and purpose:Checkpoint kinase 1 and 2 have been proposed to be potential therapeutic targets to sensitize cancers to radioor chemo-therapeutics. However, little is known about whether Chk1/2 is also a suitable target for sensitizing cancers to curcumin. In the present study, we investigated effects of Chk1/2 siRNA on curcumin-induced apopotosis in hepatoma cell line Huh7 and evaluated the effectiveness of Chk1/2 as a therapeutic target to potentiate human hepatoma to curcumin. Methods:Effect of curcumin on the cell cycle checkpoint-associated proteins was detected by Western blot. The knockdown efficacy of Chk1/2 siRNA was measured by RT-PCR and Western blot. Effect of Chk1/2 siRNA on curcumin-induced apoptosis in Huh7 cells was evaluated by DAPI staining. Effect of Chk1/2 siRNA on cell cycle distribution in curcumin-treated Huh7 cells was analyzed by flow cytometry. Results:Curcumin significantly inhibited phosphorylation of cell cycle checkpoint-associtaed proteins Chk1(S317), Cdc25C(S216) and Cdk1(Y15). Chk1 siRNA decreased Chk1 mRNA and protein by 95% and 92% and Chk2 siRNA decreased Chk2 mRNA and protein by 60% and 55% respectively as compared with negative control siRNA (P

Objective To elucidate the correlation between the dose of ultraviolet B (UVB) irradiation and apoptotic phase of keratinocytes (HaCaT cells). Methods Cultured immortalized human ker-atinocyte cell line, HaCaT cells, was irradiated with ultraviolet B (UVB) in doses of 20, 40, 60, 80, 100 and 120 mJ/cm2. Cellular viability, cell cycles and apoptosis were simultaneously detected at 2, 12, 24, 48 and 72 h after irradiation. The caspase-mediated apoptosis was detected by FITC-labelled VAD-FMK, which could irreversibly bind to activated caspases. FITC-Annexin V and PI double staining detected cell membrane-mediated apoptosis. Cell nucleus-mediated apoptosis was detected by DNA ladder electrophoresis. Results Cell cycle analysis revealed that UVB treated HaCaT cells were blocked predominantly in G2/M phase in a dose-dependent manner. Treatment with UVB decreased the viability of HaCaT cells in dose- and time-dependent manners. The rates of apoptosis were increased with increasing dose and prolongation of time after UVB irradiation. The apoptosis of UVB-treated HaCaT presented in an obvious time-dependent manner, in which caspase- and cell membrane-mediated apoptosis was predominantly in early phase and cell nucleus-mediated apoptosis predominantly in late phase. Conclusions The apoptosis of UVB treated HaCaT cells appears in dose- and time-dependent manners, which warrants further detection with multiple parameters and at different phases.

OBJECTIVE:To prepare ofloxacin hollow suppository(OHS) and to observe its in vitro dissolubility.METHODS:OHS was prepared with PEG 6000,PEG 400 and Carbopol-940 as wase material and wax as retardant.The content of ofloxacin in OHS was determined with the first order derivative UV-spectrophotometry.RESULTS:The wax,as a retardant,could retard the release of drug.The in vitro dissolution of OHS revealed the first order dissolution pattern:K0～1=27.81/h,indicating a speedy effect,K2～6=5.94/h,indicating sustained-release effect.CONCLUSION:This preparation is feasible in technology and controllabe in quality.The preparation of OHS extends the kinds of dose-form of ofloxacin

Background and purpose: Checkpoint kinase 1 and 2 have been proposed to be potential therapeutic targets to sensitize cancers to radio- or chemo-therapeutics. However, little is known about whether Chk1/2 is also a suitable target for sensitizing cancers to curcumin. In the present study, we investigated effects of Chk1/2 siRNA on curcumin-induced apopotosis in hepatoma cell line Huh7 and evaluated the effectiveness of Chkl/2as a therapeutic target to potentiate human hepatoma to curcumin. Methods: Effect of curcumin on the cell cycle checkpoint-associated proteins was detected by Westem blot. The knockdown efficacy of Chk1/2 siRNA was measured by RT-PCR and Westem blot. Effect of Chk1/2 siRNA on curcumin-induced apoptosis in Huh7 cells was evaluated by DAPI staining. Effect of Chk1/2 siRNA on cell cycle distribution in curcumin-treated Huh7 cells was analyzed by flow cytometry. Results: Curcumin significantly inhibited phosphorylation of cell cycle checkpoint-associtaed proteins Chk1(S317), Cdc25C(S216) and Cdk1(Y15). Chk1 siRNA decreased Chk1 mRNA and protein by 95% and 92% and Chk2 siRNA decreased Chk2 mRNA and protein by 60% and 55% respectively as compared with negative control siRNA (P<0.01). Inhibition of Chk1, but not Chk2, increased apoptotic rate from (21.3±1.8)% to (29.5±2.6)% (P<0.05). Neither Chk1 nor Cbk2 siRNA had any impact on cell cycle distribution in Huh7 cells induced by curcumin. Conclusion: Chk1 siRNA sensitized Huh7 cells to curcumin-induced apoptosis, suggesting that Chk1 is a potential therapeutic target to sensitize human hepatoma to curcumin.

This paper summarized the assessment model reform practiced in the postgraduate cell biology course for several years and successfully obtain a new testing method based on research papers re-porting and questioning. Before the assessment, each student searched and selected one required research paper to read and make a PowerPoint reporting document. During assessment , some students were ex-tracted to speak and comprehensive score, which was regarded as student's final examination results was made by teaching group. The rest of the students listened to speeches , questioned and filled the questions on the record sheet.Teaching group reported a score , which was regarded as part of student's final exami-nation result based on questioning record sheets and printed PowerPoint documents.This method can well evaluate students' scientific thinking and strengthen the training of scientific thinking of postgraduates.

Objective To investigate the setup errors of head and neck tumor patients with head mask-ing by TomoTherapy with megavoltage CT (MVCT),and to measure the CTV -PTV margins.Methods There were 34 patients with head and neck tumor .All patients had received MVCT scanning before radiation was deliv-ered.The MVCT images were registered with the kilovoltage CT (kVCT)images,the setup errors of the left -right (x),anterior-posterior(y),superior-inferior(z)and transverse profile rotation(Roll)were obtained by matc-hing MVCT with kVCT,followed by calculating the reasonable CTV -PTV margins with the formula M=2.5∑+0.7σ.Results Six hundred and forty MVCT images in total were received for the patients ,the systemic ±random errors in x,y,z and Roll directions were ( -0.15 ±0.55) mm,(0.30 ±0.56) mm,(0.35 ±0.71) mm and (-0.07 ±0.52)°,the CTV-PTV margin in x,y and z directions were 3.31 mm,5.32 mm and 3.35 mm.Con-clusion we demonstrate a theoretic foundation for our CTV -PTV margins in head and neck tumor patients by analyzing the setup errors ,and it also can provide necessary quality assurance for precise radiation .

Objective To seek a optimization method for lung cancer planning with Helical TomoTherapy for reducing the low dose area of total lung.Methods CT images of thirty patients with unilateral lung cancer were selected.Seven plans (Groups A,B,C,D,E,F and G) were generated for each patient using an identical optimization procedure with the conditions that implemented contralateral lung with unblocked (control group),1/4 directional block,1/2 directional block,directional block,1/4 complete block,1/2 complete block and complete block,respectively.The benefits in different schemes of reducing the low dose area of normal lung tissue were estimated,in order to provide a reference treatment plan scheme in clinical.Results Groups B,C,D and E had less influence on the target than that of group A.And there were no statistical difference between the target dosimetric parameters.The median dose and average dose of group F were increased within 0.5 Gy.The conformal index of group G had great influence on the target.The low dose area of total lung were reduced effectively in Groups C,D,E,F and G,the average decrease of V5 and V10 was 8.06％-45.26％ and 6.21％-33.95％,respectively.The V20 decreased by 1.71％-3.78％ in directional block group,while V20 increased in complete block group (2.07％-5.07％).The single treatment time was increased by 8.51％-79.22％.Conclusions The results showed that the low dose area of total lung was higher for the plan without any block limitation.It could reduce the low dose area of total lung with directional block.We should lengthen the blocking arc of contralateral lung with directional block based on the fractional treatment time and the patient's physical condition.A certain arc of contralateral lung with complete block could effectively reduce low dose area.When complete block was used,it is suggested that the arc was no more than half of the contralateral lung.

Objective To study the dose characteristics of Body γ Knife and Tomotherapy treatment plans for hepatocellular carcinoma,and compare their differences between organs at risk (OAR) dose and the range of low dose.Methods CT simulation images of twelve patients with hepatocellular carcinoma were selected,the target volume and OAR were drew by doctor.Body γ Knife and Tomotherapy treatment plans were optimized with their own planning station.The dosimetric characteristics were evaluated by dose volume histograms and were compared.To analyze the difference between the two techniques,the paired t-test was applied.Results The Dmax and Dmean of target with Body γ Knife were higher than Tomotherapy (P =0.002,0.000),but the conformal index of PTV of Tomotherapy was superior to the Body γ Knife (P =0.001).The Dmax of spinal cord and left kidney with Body γ Knife was lower than Tomotherapy (P =0.013,0.012),and it was also in the Dean of stomach and left kidney (P =0.010,0.023).In the volume dose comparison,the V40,V35,V30,V25 and V20 of normal tissue (all Body-PTV) and liver (all liver-GTV) with Body γ Knife were higher than Tomotherapy (P =0.001,0.001,0.001,0.007,0.029),but the V10 and V5 were lower (P =0.019,0.031),the Dmax of stomach,Dmean of right kidney and liver were no statistical difference (P =0.247,0.308,0.401).Conclusions Both treatment plans could meet the clinical dosimetric need,by the same prescription dose,Dmax and Dmean of target of Body γ Knife were higher than Tomotherapy.Tomotherapy had excellent dose-target conformal and could reduce the range of V25-V40 of OAR and normal tissue,but the range of V5-V10 was increased obviously.

ObjectiveTo further evaluate the value of the stereotactic gamma-ray body radiation therapy ( γ-SBRT ) for patients with stage Ⅰ / Ⅱ non-small cell lung cancer ( NSCLC ) basing on the preliminary studies.MethodsTwenty-nine eligible patients with stage Ⅰ / Ⅱ NSCLC who is unable or unwilling to receive surgery underwent treatment prospectively with γ-SBRT (OUR-QGD).Patients were fixed by vacuum bag.Each patient underwent slow CT simulation at 5 s/slide with thickness of 5 mm and interval of 5 mm to take into consideration tumor motion.A total dose of 50 Gy was delivered at 5 Gy/fraction to 50％ isodose line covering 100％ of the PTV,with 60 Gy at 6 Gy/fraction to 60％ isodose line covering 90％ of the CTV,70 Gy at 7 Gy/fraction to 70％ isodose line covering 80％ of the GTV,and 10 times finished in 2 weeks,5 fractions per week.ResultsThe follow-up rate was 97％.The 6 month local tumor response rate was 93％,with CR 86％,and PR 7％.The 1-,2-year local control rates were both 93％.The 1-,2-year overall survival rates for the whole group,stage Ⅰ and stage Ⅱ were 97％ and 89％,100％ and 92％,67％ and 67％,respectively.The 1-,2-year progression-free survival were 90％ and 86％,respectively.34％ of the patients had acute radiation toxicities ( grade 1,2 and 3 in 6,2 and 2patients,respectively),and 38％ late radiation toxicities ( grade 1 and 2 in 10 and 1,patients).Conclusions γ-SBRT is a safe and effective treatment regimen,resulted in promising local control and survival with minor toxicity.