An evaluation system including experiment preparation,experiment process,com-prehensive design of experiment,experiment skills and written exam was established in order to adapt to the experimental teaching reform in our school. Experimental preparation assessment was to evaluate‘preview and self-evaluation report’prepared and submitted by students. Experimental process assess-ment was to evaluate students' classroom performance and experiment reports. Assessment of compre-hensive design experiments was to evaluate the overall participation of students. Skill assessment was consisted of oral test and experiment operation test. Final written examination,mainly consisting of subjective questions,emphasized on student's flexible use of knowledge and ability to solve practical problems. The evaluation system of promoting student's learning and teacher's teaching through the examination not only fully arouse student's attention on experiment,but also make teachers more ob-jectively and really understand students' learning situation and the teaching effectiveness.

OBJECTIVETo investigate the effect of hydroxycamptothecin (HCPT) on the proliferation, cell cycle and apoptosis of human lung carcinoma cell line A549.

METHODSThe growth of A549 cells exposed to HCPT was observed by staining with acridine orange/ethidium bromide dye. Agarose gel electrophoresis was performed to detect DNA fragmentation of the apoptotic cells. The cell cycle distribution of the exposed cells was analyzed using flow cytometry, and cell apoptosis was examined with annexin V-FITC/PI staining. RT-PCR was used to investigate Bcl-2 gene expression changes in the exposed cells.

RESULTSAgarose gel electrophoresis of the DNA from HCPT-treated cells showed a DNA ladder, and typical apoptotic appearance of the exposed cells was observed under fluorescence microscope. Treatment of A549 cells with 1 µmol/L HCPT for 24 h resulted in a cell apoptosis rate of 18.11%, significantly higher than the rate in control cells (0.09%, P<0.05). The treatment also caused a significant reduction of Bcl-2 mRNA expression by 70% (P<0.05).

CONCLUSIONHCPT can significantly inhibit the proliferation, induce apoptosis, and down-regulate Bcl-2 gene expression in human lung carcinoma cell line A549, suggesting the involvement of Bcl-2 gene in the inhibitory effect of HCPT on A549 cells.

Camptothecin ; analogs & derivatives ; pharmacology ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Down-Regulation ; Gene Expression Regulation, Neoplastic ; drug effects ; Genes, bcl-2 ; Humans ; Transfection

Objective To research the effect ofparecoxib on hippocampal nerve cell apoptosis and expressions of B cell lymphoma/lewkmia-2 (Bcl-2),Bcl-2 associated X protein (Bax) and caspase-3 of epilepsy rats.Methods Thirty SD male rats were randomly divided into three groups (n=10):control group,parecoxib treatment group and epilepsy group.The rats in the parecoxib treatment group and epilepsy group were injected with 4 mg/kg of parecoxib and same volume of saline,respectively,and 3 d after that,they both were injected intraperitoneally with 3 mmol/kg of lithium chloride,and then,20 h after that,they were injected intraperitoneally with 30 mg/kg ofhydrochloride pilocarpine; while rats in the control group were only injected intraperitoneally with the same volume of saline.The behavior changes of rats in the three groups were observed.After 7 d,terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) was used to evaluate the neuronal apoptosis and Western blotting was employed to evaluate the expressions of Bcl-2,Bax and caspase-3 in the hippocarnpus of all groups.Results All epilepsy rats were very irritable; spontaneous seizures (SRS) times of precoxib treatment group were significantly reduced as compared with those of epilepsy group (P＜0.05).As compared with those in the control group,the Bcl-2,Bax and caspase-3 expressions and Bcl-2/Bax ratio in the epilepsy group were increased with statistically significant differences (P＜0.05); As compared with those in the epilepsy group,the Bcl-2,Bax and caspase-3 expressions and Bcl-2/Bax ratio in the precoxib treatment group were decreased with statistically significant differences (P＜0.05).As compared with that in the control group,the number of TUNEL positive cells in hippocampus of rats in the precoxib treatment group and epilepsy group were significantly increased (P＜0.05); as compared with that in the epilepsy group,the number of TUNEL positive cells in the hippocampus of precoxib treatment group was statistically reduced (P＜0.05).Conclusion Parecoxib can reduce the apoptosis of hippocampus neurons through inhibiting the protein expressions of Bax and caspase-3 to affect the Bcl-2 protein expression,whose mechanism may be related to the pathways of Bcl-2/Bax and Caspase-3 proteins.

OBJECTIVE:To study 3D-QSAR of pyridine heterocyclic ring PI3K inhibitor as anti-renal cancer drug,and to provide reference for the design and R&D of new anti-renal cancer inhibitors. METHODS:The data of structure and active value (pIC50) of 30 pyridine heterocyclic ring PI3K inhibitors were collected. After Sybyl-X 1.1 software used for molecular superimposition, CoMFA and CoMSIA model were established to investigate three dimensional field, electrostatic field, hydrophobic field,hydrogen bond donor site and hydrogen bond acceptor field of PI3K inhibitor molecule. Sybyl-X 1.1 software was used for molecular docking,and the mechanism of PI3K inhibitor molecule and receptor target protein were analyzed. PyMOL V1.5 software was used to design new PI3K inhibitor molecules. The activity of inhibitor molecules was predicted with CoMFA and CoMSIA model. RESULTS:The cross validation coefficients of CoMFA and CoMSIA model were 0.617 and 0.601, fitting validation coefficients were 0.969 and 0.974,and external predictive correlation coefficients were 0.656 and 0.670, respectively. In CoMFA model, contributions of three dimensional field and electrostatic field were 56.2% and 43.8%respectively. In CoMSIA model,contributions of three dimensional field,electrostatic field,hydrophobic field,hydrogen bond donor site and hydrogen bond acceptor field were 41.0%,31.3%,21.1%,2.4%,4.2%. After molecular superimposition,small steric hindrance,strong positive and hydrophilic groups introduced nearby R1 group of common skeleton could help to enhance the activity of molecules. The results of molecular docking showed that PI3K inhibitor molecule formed three hydrogen bonds with the key amino acids ALA805,VAL882 and THR887 of receptor target protein,with the length of 1.84,1.99,1.99 ?. According to above information,6 new molecules were designed,among which predicted pIC50 of 2 molecules with higher activity were 3.211,3.247(CoMFA method)and 3.238,3.222(CoMSIA method). CONCLUSIONS:Established new CoMFA and CoMSIA model have good prediction ability and statistical stability. Contribution of three dimensional field is higher than that of electrostatic field,and the influence of hydrophobic field on molecular activity can not be ignored. Pyridine heterocyclic ring PI3K inhibitors have strong hydrogen bonding role with receptor target protein. 3D-QSAR can provide reference for the design,reconstruction and drug R&D of new PI3K inhibitor molecule.