The ampC ?-lactamases gene in Escherichia coli(E.coli) is different from other Gram-negative bacteria.E.coli contains a chromosomal ampC gene which has a weak promoter as well as a transcriptional attenuator.The promoter of the ampC gene in E.coli is part of the preceding frd operon,the attenuator of the ampC gene is a transcription terminator for the frd operon.The ampC regulatory gene,ampR,is absent.Strains carrying the wild-type gene produce a low basal amount of AmpC.Studies on the molecular basis of AmpC overproduction in E.coli have shown that some hyperproducers contain mutation in the promoter region and/or attenautor and/or ampC-coding region of ampC,while others contain more than one copy of ampC.Acquisition of a stronger promoter or insertion of an insertion element containing promoter sequences or regulatory gene ampR has also been proposed as the molecular basis of hyperproduction of AmpC in some E.coli strains.Plasmid-mediated AmpC ?-lactamases have been discovered frequently in E.coli strains.This is another reason for hyperproduction of AmpC ?-lactamases.

Objective To study the effect of the inhibitor of apoptosis protein,Livin on proliferation and multi?drug resistance of lung adenocarcino?ma cells A549. Methods A549 cells were transfected with the eukaryotic expression vector pcDNA3.1?Livin. A549 cell clone with stable expres?sion of Livin was obtained through G418 screening. Expressions of Livin mRNA and protein in the transfected cells were respectively measured by re?verse transcription polymerase chain reaction(RT?PCR)and Western blot. The distribution of cell cycle phase was determined using flow cytometry. The level of P?gp mRNA and protein in A549 cells transfected with pcDNA3.1?Livin was detected by RT?PCR and Western blot. The analysis of multi?drug resistance of A549 treated with different chemotherapeutics was performed by MTT. Results The mRNA and protein expressions of Liv?in were both significantly increased in the transfected A549 cells. The flow cytometry analysis showed there was higher percentage of S phase and low?er percentage of G0/G1 phase in A549 cells transfected with pcDNA3.1?Livin. Compared with control groups,the expression of P?gp mRNA and pro?tein was increased in A549 cells transfected with pcDNA3.1?Livin,which showed a higher drug resistance and lower sensitivity to chemotherapic drugs such as ADM,MTX,CTX,and DDP(P<0.05). Conclusion Overexpression of Livin could enhance the proliferation of A549 cells,and high expression of P?gp caused by Livin could serve as one of the causes for multi?drug resistance in lung adenocarcinoma against chemotherapies.

Objective To investigate the effects of small interfering RNA (siRNA) silencing Nanog gene on the ability of migration and invasion of the human lung adenocarcinoma A549 cells. Methods The human lung adenocarcinoma A549 cells were transfected with siRNA targeting Nanog gene , and three experiment groups were set up. The expression level of Nanog was detected using reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. Cell migration was examined by wound healing assay and cell invasion was detected by Transwell assay. Results The Nanog silencing cell group (A549-siNanog) showed much lower level of Nanog mRNA and protein (0.40 ± 0.06, 0.50 ± 0.03) than A549-siNC cell group (0.97 ± 0.03, 0.85 ± 0.02; P < 0.05) under RT-PCR and Western blot analysis. Meanwhile, the wounded area filled rate and the number of invaded cells of A549-siNanog cell group (57% ± 0.04, 69.60 ± 17.14) were decreased significantly compared to A549-siNC cell group (95% ± 0.02, 209.60 ± 15.40; P < 0.05). Conclusion siRNA targeting human Nanog could specially suppress the expression of Nanog gene in lung adenocarcinoma A549 cells. In this way, it couldsignificantly reduce the capability of migration and invasion of A549 cells.

Objective To establish the isodose curves and dose calculation models of()~(125)I seed plane implantation using the three-dimensional treatment planning system(3D-TPS). Methods The isodose cures of 1 000 cGy,3 000 cGy,6 000 cGy,9 000 cGy,12 000 cGy,15 000 cGy,and 20 000 cGy and dose calculation models of triangular,quadrilateral,hexagon,and dodecagon patterns of()~(125)I seed plane implantation were created using the 3D-TPS.The isocenter dose pattern of 0,0.5,1.0,1.5,2.0,2.5,3.0,and 4.0 cm from the plane center was calculated with 3D-CRT. Results The study showed that if doses were less than 10 Gy at 2.0 cm,2.5 cm,3.0 cm and 4.0 cm apart from the center of triangular,quadrilateral,hexagon,and dodecagon patterns and the distance was beyond 1 cm between seeds,there was a low dose region in the centeral point. Conclusions The study showed that the isodose distribution curves and dose calculation models in plane implantation were primarily established using the seed implantation 3D-TPS.

Objective To investigate the effect and underlying mechanism of single,fractioned and continuous low dose rate radiation on CL187 colorectal cancer cell line.Methods CL187 cells were exposed to 6 MV X-rays at a high dose rate of 4 Gy/min and 125Ⅰ seed at a low dose rate of 2.77 cGy/h with three groups:single dose radiation group (SDR),fractioned dose radiation group (FDR) by 2 Gy/f,and continuous low dose rate radiation group (CLDR).The radiation doses were 0,2,4 and 8 Gy.Total cell number and cell viability were determined by trypan blue.Clone forming assay was used to evaluate the cell proliferation ability.The percentage of apoptosis cells was analyzed by flow cytometry.Western blot was used to detect the protein expression levels of PHLPP2,PTEN and Bax.Results Compared with SDR and FDR groups,the total cell number and survival fraction of CLDR group decreased.The relative biological effect (RBE) for 125Ⅰ seeds compared with 6 MV X-rays was 1.41.The percentage of apoptosis cells of CLDR group was significantly increased (t =-15.08,-11.99,P ＜ 0.05).The expression level of Bax increased in CLDR group,while no obvious changes were observed on PHLPP2 and PTEN among three groups.Conclusions The expression level of PHLPP2 increaseS in SDR,FDR and CLDR group,while it seems that it was not influenced by dose rate.The expression level of Bax increased in three groups,while more colorectal CL187 cells in CLDR group may be killed due to the increase of Bax expression.

Objective To observe the multi-segmental cervical spondylotic myelopathy with simple anterior or posterior joint pre-and post-operative prognosis of spinal cord function improved and the status, explore co-operation after the clinical efficacy and complications. Methods The clinical data of 298 cases of multi-segmental cervical spondylotic myelopathy with anterior or posterior of the simple pre-and post-joint surgery from January 2001 to January 2008 were retrospectively analyzed. The clinical efficacy, titanium anterior cervical decompression and fusion surgery net implanted titanium plate fixation 121 cases, posterior open-door laminoplasty 112 cases, 65 cases of combined surgery before and after. JOA score line of spinal cord function and somatosensory evoked potential, as compared 3 groups after surgical efficacy. Results All patients were followed-up 1- 7 years, averaged (4.7±1.4) years. The anterior cervical decompression and fusion surgery titanium mesh implanted titanium plate fixation to improve the rate was 78.1%, excellent and good rate was 72.7%(88/121). Posterior open-door laminoplasty to improve the rate was 70.6%, excellent and good rate was 66.1% (74/112), there was statistically significant between them (P < 0.05). After anterior surgery, improving rate was 86.7%, excellent and good rate was 83.1% (54/65). Anterior and posterior combined surgery before and after comparison was significant (P < 0.05), regardless of near-term results, long-term effects were better than that of anterior or posterior surgery. Conclusions The spinal cord in the treatment of multi-segmental operation of cervical spondylosis after anterior surgery is obviously superior to the efficacy of anterior or posterior surgery alone. Spinal stability anterior, posterior, after a joint operation before the lower one by one.

Objective To investigate the inhibition effect of continuous low dose rate radiation by 125Ⅰ radioactive seeds on Hep-2 cells and the corresponding mechanisms.Methods Hep-2 cells were divided into three groups,control group,single dose radiation group with high dose rate form X-rays (SDR) and continuous low dose rate radiation by 125Ⅰ seeds group (125Ⅰ-CLDR).After exposure to SDR and 125Ⅰ-CLDR,colony formation assay was used to determine the radiosensitivity and RBE,trypan blue exclusion assay was used to determine cell proliferation,and flow cytometry was used to detect cell apoptosis and cell cycle arrest.Results The radiosensitivity of Hep-2 cells to 125Ⅰ-CLDR was higher than that to SDR.The RBE of 125Ⅰ-CLDR versus SDR was approximately 1.61.The α/β ratio of 125Ⅰ-CLDR group was higher than that of SDR group.Both SDR and 125Ⅰ-CLDR inhibited cell proliferation (t =30.9,40.7,P＜0.05),in which 125Ⅰ-CLDR was stronger than SDR (t =9.8,P＜0.05).In addition,the incidences of apoptosis and G2/M arrest induced by125Ⅰ-CLDR were also stronger than those induced by SDR (t =5.8,19.8,P ＜ 0.05).Conclusions 125Ⅰ-CLDR generates more serious inhibition effects than SDR on reducing cellular DNA repair capacity,inducing cell apoptosis and G2/M arrest and inhibiting proliferation of Hep-2 cells.

Objective To investigate cleanliness of hospital environmental object surfaces and hands of health care workers(HCWs).Methods The adenosine triphosphate (ATP)bioluminescence assay was used to detect object surfaces and hands of HCWs in a hospital,on-the-spot intervention was conducted.Results The qualified rates of hospital environmental object surfaces and ventilator-relevant object surfaces were 58.14% (200/344)and 69.88%(116/166)respectively,the qualified rate of ventilator tracheal intubation site was low (29.17%);the qualified rate of telephone surfaces was the lowest (27.27%).The qualified rates of ventilator-relevant object surfaces used con-tinuously for ≥48h and <48 h were 56.70%(55/97)and 88.41 %(61/69)respectively,there was significant differ-ence between the two(χ2 =19.26,P <0.01).The qualified rates of HCWs’hands before and after intervention were 34.18% and 85.58% respectively,relative light unit (RLU)values were (1 033.46±106.20)and (80.46±10.68) respectively,the qualified rates and RLU before and after intervention were both significantly different (both P <0.01).Conclusion Contamination of object surfaces and hands’of HCWs in hospital dynamic environment is seri-ous,ATP bioluminescence detection and on-the-spot intervention is helpful for improving cleanliness of hospital en-vironment object surfaces and HCWs’compliance to hand hygiene.

Objective:To investigate the psychological changes of leukemia children and their parents during treatment and rehabilitation,and provide the basis for medical staff giving humanistic care to them.Methods:20 leukemia children and their parents were interviewed and accepted one to one individualized intervention after ana-lyzing the information and posing problems.Results:Leukemia children need long-term treatment, and chemo-therapeutic drugs has obvious side effect, which make parents and children painful and easily cause negative emo-tion and psychological problems.Timely psychological intervention and humanistic care are good for disease recov-ery.Conclusion:According to children′s psychological characteristics in different treatment stages and parents′psy-chological needs conclusion was made that humanistic care on leukemia children should include:to make the pa-tient comfortable first, meet the psychological demands of children in different ages, improve medical technology, carry out painless therapy, enhance communication skills between doctors and patients, give the necessary social support, and improve the children′s quality of life.

Objective To investigate the effect of cetuximab (C225) on the radiosensitivity of colorectal cancer cells CL187 and underlying mechanism.Methods Cell survival was detected by colony forming assay.The levels of apoptosis and cell cycle distribution were determined by flow cytometer.The mitotic ratio was measured by Wright' s-Giemsa mixed coloring method.The protein levels of Bax and Bcl2 were detected by Western blot.Results The sensitizing enhancement ratio of C225 was approximately 1.4.C225 treatment and 125I seed radiation induced G1 cell cycle arrest individually.C225 increased the radiation-induced apoptosis (t =6.6,P ＜ 0.05) and cellular Bax/Bcl-2 ratio (t =9.4,P ＜ 0.05),but did not increase radiation-induced G1 arrest.In addition,there was no difference in mitotic index among different groups.Conclusions C225 sensitizes CL187 to 125I seed irradiation,which might be related with increase of radiation-induced apoptosis.