although there are many repair pathways in cells, some lesions still escape repair inevitably and remain in genome. In cells, the molecular mechanism of translesion DNA synthesis has been one of the major unsolved problems in DNA repair for a long time. Recently, it was found that the members of a structurally related UmuC/DinB protein superfarnily have DNA polyrnerase function. Unlike the classical replicative DNA polymerases, these newly identified DNA polymerases can carry out translesion DNA synthesis in both error prone/mutagenic and/or error-free ways. It was also found that their functions are conserved from bacteria to human.

Objective:To prepare bryostatins freeze-dried liposomes and to establish a quality standard for the liposomes.Methods: Film dispersion technique was used to encapsulate bryostatins with liposomes.Chloroform was taken as the solvent and was volatilized by revolving.Emulsification was performed with the probe after hydration,then the supporting agent was added for freeze drying.An RP-HPLC method was developed to determine the freeze-dried liposome content.The separation was performed with a Agilent C_(18) Column and the mobile phase was methanol-water in gradient elution 7525(0-38 min),(73.726.3)(38-45 min),7921(45-48 min) by a flow rate of 1.5 ml/min,with the UV detector set at 228 nm.Zetasizer was used to determine the size of liposomes and the entrapment efficiency was determined with centrifugal ultrafilter.Results: The freeze-dried liposomes were homogeneous and the mean diameter was 0.423 ?m.The standard curve was linear over the range of 44-220 ?g/ml,r=0.999 8.The intra-day and inter-day RSDs were less than 2.0%.The recoveries of the high,middle and low concentrations(88,110,and 132 ?g/ml) were 100.8%,98.4%,and 100.9%,respectively.The detection limit was 4.4 ng,the quantitation limit was 17.6 ng,and the entrapment efficiency was 98.68%.Conclusion: The film dispersion technique is(suitable) for preparation of bryostatins liposomes.The method in this study is easy-to-use,accurate,and with good(repeatability.)

A Review] A large quantity of intracellular structural and regulatory proteins can be covalently attached to ubiquitin posttranscriptionally and thus modified. The ubiquitination of proteins serves as targeting signals, making ubiquitinated proteins distributed to different parts of the cells, changing the activities, the interaction between macromolecules and the half-life of proteins. Therefore, ubiquitin conjugation is implicated in numerous metabolic processes in eukaryotes. Ubiquitin conjugates its protein substrates via a cascade reaction. This paper is a review of recent advances in this area.

Objective To investigate the effects of source to image receptor distance (SID) on the image quality and entrance surface dose (ESD) in the chest digital radiography (DR) for infants.Methods Anthropomorphic chest phantoms were exposed to 60 kVp and different values of SID ( 150 -80 cm with the interval of 10 cm,totally 8 groups) so as to record the values of mAs and ESD.The SID values of 110 cm and 90 cm with the moderate and low ESD values were selected for clinical test.Forty-two hospitalized infants,aged 12 months (8 months to 2 years) underwent chest DR with the SID of 110 cm before admission and 90 cm before discharge respectively.The values of ESD were recorded and compared.Three experienced experts assessed the quality of 84 pieces of images.Results The values of mAs and ESD decreased gradually along with the decrease of the SID from 150 cm to 80 cm.All the 84 images from the 42 infants met the demands for diagnosis.There was no significant difference in the score of image quality of the group with the SID of 110 cm (4.4±0.3) and 90 cm(4.2±0.4) (t=0.453,P＞0.05).The value of ESD of the group with the SID of 90 cm was significantly lower than that of the group of SID of 110 cm by 0.003 4 mGy ( t =12.001,P ＜ 0.05 ).Conclusions The image quality of chest DR could meet the demands for diagnosis in spite of the value of SID,however,the SID value in chest DR significantly might influence the ESD.The SID value of 90 cm shoud be recommended in chest DR for infants.

OBJECTIVE To investigate whether α-lipoic acid(α-LA)can promote the anti-prolifera-tion effect of pyrrolidine dithiocarbamic acid(PDTC)in Hep-2 cells. METHODS The laryngeal carcino-ma Hep-2 cells were cultured with α-LA,PDTC or α-LA+PDTC respectively for 12,24 and 48 h. The proliferation of Hep-2 cells was detected by WST-1 assay and soft agar colony formation while apoptosis and cell cycle were analyzed by Hoechst33258 staining and flow cytometry. RESULTS α-LA 5 -500 μmol·L-1 could not inhibit Hep-2 cell proliferation,but PDTC 5 -50 μmol·L-1 could( P ﹤0.05,P ﹤0.01). The cell proliferation inhibitory rate of PDTC 5 μmol·L-1 combined with α-LA 5,10 and 20 μmol·L-1 groups was much higher than in control group(P﹤0.01)and PDTC alone group(P﹤0.05). When α-LA 5 μmol·L-1 was used in combination with PDTC 5 μmol·L-1 for 12-48 h,the cell proliferation was inhibited in a time-dependent manner(r=0.987,P﹤0.05). When the cells were treated for 24 h,the number of soft agar colony formations in combined group was significantly smaller than that of both α-LA alone group(P﹤0.01)and PDTC alone group(P﹤0.05). The result of Hoechst33258 staining and flow cytometry indicated that after combined treatment with PDTC 5 μmol·L-1 and α-LA 5 μmol·L-1 for 24 h,the level of apoptosis and the percentage of cells in G2 / M stage were significantly increased compared with PDTC alone or α-LA alone treatment. CONCLUSION α-LA can enhance the anti-proliferation and pro-apoptosis effect of PDTC in Hep-2 cells.

AIM:To establish FL- CROC -1 - cell line in which CROC -1 gene expression was blocked and study the role of CROC -1 gene in cell growth. METHODS:The appropriate length cDNA fragment of the recently identified human gene CROC -1 which encodes ubiquitin-conjugating enzyme like protein(Ubc-like protein) was cloned into the reconstructed eukaryotic expression vector pMAMneo-amp - by antisense strategy. The recombinant plasmid which can express CROC -1 antisense RNA was selected by restriction enzyme map analysis. The antisense expression recombinant plasmid pMAM-anti CROC -1 was then transfected into human amnion FL cells by a modified calcium phosphate-mediated transfection procedure and selected with MEM medium containing 400 ?g/mL geneticin. Finally ,the growth rate of the G418 resistant FL- CROC -1 - cell line was determined. RESULTS:When the antisense inhibition of CROC -1 gene expression was induced by dexamethasone, the growth rate of the FL- CROC -1 - cell line was obviously slower as compared with that of the control FL cell and FL-MAMneo cell which was established by transfection of plasmid pMAMneo-amp - ( P

An overall improvement of teaching quality is the core task of the reform and the development of higher education. Based on the analysis of the main factors of affecting the teaching quality in universities and combined with the implementation of “views on improving the overall qual-ity of higher education”by the Education Ministry, countermeasures for improving the teaching quality of undergraduates have been proposed such as increasing higher education funds investment to im-prove the condition of running a school, paying attention to the construction of teaching management staff to improve the level of teaching management, establishing Teacher Development Research Center to consolidate the fundamental position of undergraduate teaching , utilizing the high-quality social resources to implement the collaborative education innovation, and improving the personnel training system to strengthen the teaching quality standard .

Objective To evaluate the relationship between carotid arteriosclerosis and ischemic cerebral vascular disorders (ICVD). Method We examined 126 ICVD patients and 126 non-ICVD patients in the alterations of carotid dimension and intramembrane morphology with magnetic resonance angiography (MRA). Results Carotid plaques to various extent were detected in 82 cases of ICVD patients and 38 cases of non-ICVD patients. The incidence of carotid plaques was 68.3% and 35.7%, respectively in these two groups of patients. Furthermore, patients either with age over 60 years, hypertension, or hyperlipemia were found to be more susceptible to carotid arteriosclerosis. Conclusion MRA is very useful to detect early-stage carotid arteriosclerosis, and the occurrence in the carotid arteriosclerosis is closely related to ICVD.

Objective To investigate the efficacy of monotherapy or combination of ACEI and ARB in treating diabetic nephropathy(DN). Methods 183 patients with DN were randomly allocated into three treatment groups: benazepril,losartan or the combination of these two drugs for 12 weeks.The changes of blood pressure, proteinuria, serum potassium and creatinine, creatinine clearance(Ccr)were observed before and after treatment. Results Both of benazepril and losartan reduced blood pressure and proteinuria efficiently.And their effects were similar.In contrast, the reduction in proteinuria was greater in the combination therapy than in treatments of either drug alone(P<0.05), but their reductions in blood pressure were achieved to the same level(P>0.05).There were not significant differences in serum levels of potassium, creatinine and Ccr before and after treatment(P>0.05). Conclusion A combination of ACEI and ARB in patients with DN produces a better anti-proteinuric effect than either of the monotherapies.This protection is not dependent on changes in blood pressure.

Objective To evaluate the difference of efficacy between continuous subcutaneous insulin infusion(CSII)and continuous intravenous insulin infusion(CVII)with human insulin in patients with diabetic ketoaciduria or ketoacidosis(DKA). Methods 120 patients with DKA were randomized into two groups,one was CSII group by a portable insulin pump(60 cases),the other was CVII group(60 cases).Results Both of CSII and CVII were effective in controlling blood glucose levels.CSII therapy provided better glycemic control(P