Objective To establish a pretreatment method which is applicable to the determination of strontium(Sr)in toothpaste by flame atomic absorption spectrometry.Methods The pretreatment was performed by using digestion pot technique, with lanthanum nitrate as the anti-interference agent.Flame atomic absorption spectrometry was used in this study,the parameters of digestion temperature and the results of two pretreatment methods were compared.Results The toothpaste sample was digested completely by using digestion pot technique with little examined elements lost during digestion.Time-saving and pollution-free were seen in the test.The detection limit of this method was 0.02?g/ml,and the RSDs were 0.98%-3.01%.The recovery rate was at the range of 94.7%-110%.No significant difference was seen between these two pretreatment methods.Conclusion This method has advantages of high sensitivity and precision in the determination of strontium in toothpaste by flame atomic absorption spectrometry,so it can be employed in various laboratories.

OBJECTIVE This study is to investigate the effects on nasopharyngeal carcinoma cell lines(CNE-2Z)induced by As2O3 and its possible mechanisms.METHODS CNE-2Z cells were treated with various concentrations of As2O3 for different times.The IC50 values were detected by trypan blue stain assay to choose the optimal concentration of As2O3.Cell cycle redistribution was analyzed by flow cytometry.The expression levels of p16、 RASSF1A、DNMT 3B mRNA were assessed by RT-PCR.RESULTS The suppression of cell proliferation by As2O3 was time and dose-dependent.After being treated with different concentration of As2O3,the IC50 values of As2O3 were(1.50?0.05),(1.09?0.13),(0.65?0.04)?mol/L at 24,48,and 72h,respectively.As2O3 also arrested CNE-2Z cells in G2/M phase of cell cycle.After CNE-2Z cells being treated with As2O3,the expression of RASSF1A mRNA were up-regulated(P

Objective To report the medium-term follow-up results for deep venous thrombosis(DVT) after total knee arthroplasty(TKA).Methods Between July 2003 and March 2004,55 patients(63 knees)who had had TKA were followed up for DVT.In follow-ups 1 to 2 weeks after TKA,their clinic symptoms,Doppler ultrasonograms and venograms were analyzed.In the following out-patient follow-ups done at every six months,we observed their clinic symptoms and Doppler uhrasonograms for the operated lower extremity.Venography was done only for those who had severe DVT symptoms.Results The venography one week after TKA conformed that DVT occurred in 34 patients(41 knees,61.8%).Two weeks after operation,DVT vanished in 12 cases,but deterio- rated to the proximal part in two cases.The follow-ups averaged 36.6 months(range,32 to 40 months).The results at five time points showed that the incidence of DVT did no decrease with lapse of time(P＞0.05).Conclusion No matter whether DVT occurs in the perioperative period,incidence of DVT in the medium term varies little.

Objective To construct the prostatic specific promoter used to induce the gene therapy aiming at androgen independent prostatic carcinoma and evaluate the activity. Methods Through two steps of polymerase chain reaction (PCR), androgen response elements (AREs) in rPB were replaced by synthetic retinoic acid response elements (RAREs). Then the modified rPBs were connected with the plasmid. The activity was evaluated. Results Constructions were confirmed to be successful by electrophoresis and gene sequencing. Conclusion Modified rPB should be the prostatic specific promoter which can induce the gene therapy aiming at androgen-independent prostatic carcinoma controlled by retinoic acid. After being constructed, the modified rPBs were used to confirm our ideas about the experiment design and the capability inducing the gene expression of different modified rPBs was compared.

Objective: To study the relationship between the patient satisfaction with complete denture and the pain perception threshold (PPT) of alveolar ridge mucosa. Methods: Forty-five edentulous patients with complete denture were investigated with the questionnaire of patient satisfaction, PPT of alveolar ridge mucosa in the patients was measured with a pressure algometer. Results: No difference was found in the PPT of alveolar ridge mucosa between the left and the right side. The PPT was found to be higher in maxillary site than in mandibular side(P

Objective To explore the pathological changes of lung, expression of the relevant inflammatory factors and oxidative stress markers of Sprague-Dawley (SD) rats undergoing autologous orthotopic liver transplantation (AOLT). Methods Thirty SD rats were randomized into sham group and AOLT group. The pathological changes of lung, expression of the relevant inflammatory mediators and oxidative stress markers were detected . Results ( 1 ) Compared with the sham group , the pathological scores of lung tissue in AOLT group increased significantly and reached its peak at 8 h after surgery. Then the pathological scores decreased to the level of sham within 24 h to 48 h after surgery; (2)The relative expression of inflammatory mediators including TNF-α, IL-1β, IL-6 and IL-8 increased significantly and reached its peak at 8 h after surgery in AOLT group. Then decreased to the level of sham group within 24 h to 48 h after surgery; (3)The change trends of MDA and H2O2 were similar to inflammatory mediators.The relative SOD expression decreased significantly and touched the nadir at 8h after surgery and then increased. Conclusion The pathological changes of lung expression, the relevant inflammatory mediators and oxidative stress markers of rats underwent AOLT were consistent.

Objective To investigate the value of plasma troponin ,B-type natriuretic peptide and D-dimer in the clinical diagnosis of acute pulmonary embolism .Methods A total of 116 patients with acute pulmonary embolism were randomly selected and divided into high-risk group and low-risk group according to the patient′s condition ,58 patients in each group .Enzyme-linked immunosor-bent assay was used to detected levels of plasma troponin ,B-type natriuretic peptide and D-dimer .Results The plasma troponin and B-type natriuretic peptide levels in the high-risk group were significant higher than those of the low-risk group(P<0 .05) ,but there was no significant difference on D-dimer level(P>0 .05) .The positive rate of plasma troponin(61 .21% )and B-type natriuretic pep-tide(74 .14% )were significant higher than that of D-dimer(36 .21% ) ,the differences were significant(P<0 .05) .The sensitivity of D-dimer was 81 .4 % ,specificity was 86 .7% .The sensitivity of plasma troponin was 95 .6% ,the specificity was 86 .7% .The sensi-tivity of B-type natriuretic peptide was 97 .1% ,the specificity was 95 .9% .The sensitivity and specificity of plasma troponin and B-type natriuretic peptide were significant higher than D-dimer(P<0 .05) .Conclusion Plasma troponin ,B-type natriuretic peptide and D-dimer have certain implications for the clinical diagnosis of acute pulmonary embolism ,but plasma troponin ,B-type natriuretic peptide has better sensitivity and specificity compared with D-dimer .

Objective To establish a cellular model for the expression of the C-type lectin dendritic cellspecific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN),and to provide a basis for the functional analysis of DC-SIGN.Methods The cDNA of DC-SIGN was obtained via PCR,and cloned into the eukaryotic expression vector porcine cytomegalovirus-enhanced green fluorescent protein (PCMV-EGFP) with EGFP at the N terminal of DC-SIGN.Then,the recombinant PCMV-EGFP-DC-SIGN plasmid was transfected into HEK293T cells followed by the detection of DC-SIGN expression using PCR,Western blot and flow cytometry.Confocal microscopy was performed to localize the expression of DC-SIGN-EGFP and visualize the recognization and internalization of the Derp2 allergen by DC-SIGN.Results The recombinant fluorescent fusion protein-expressing plasmid was successfully constructed.Both PCR and Western blot confirmed the expression of DC-SIGN.Flow cytometry showed that the expression of DC-SIGN was increased by approximately 50％ in HEK293T cells transfected with the recombinant expression plasmid compared with those untransfected.As confocal microscopy showed,the green fluorescence-labelled DC-SIGN was located on the cell membrane,which could bind to the red fluorescence-labelled antigen Derp2 and internalize it into the cells.Conclusions The recombinant DC-SIGN-EGFP fusion protein is characteristically located on the surface of 293T cells,which can be recognized by the DC-SIGN-specific antibody and is capable of internalizing the allergen Derp2,and may serve as an ideal cell model for further studies on molecular function of DC-SIGN.

Objective To synthesize herpes simplex virus (HSV) envelope glycoprotein gC using gene engineering techniques,and to verify its expression.Methods Two separate parts of the HSV envelope glycoprotein gC,i.e.,GC-F and GC-R,were respectively synthesized.The GC-F and GC-R genes were synthesized,subcloned into the expression vectors pSumo-Mut (containing recognition sequences for endonucleases Stu1 and XhoI) and pCzn1 (containing recognition sequences for endonucleases NdeI and XhoI) respectively to form the recombinant plasmids pSumo-Mut-GC-F and pCzn1-GC-R.E.coli BL21 Arctic Express (DE3) cells were transformed with the two recombinant plasmids separately.Isopropyl thiogalactoside (IPTG) was used to induce the expression of target protein which was subsequently purified by nickel affinity chromatography.Finally,Western blot was performed to verify the reactivity of the synthesized protein with the sera of HSV-1-positive patients.Results Both GC-F and GC-R genes were synthesized by a total gene synthesis method.As sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE) showed,the fusion proteins were mainly distributed in the sediment layer.The purity of GC-F and GC-R proteins was over 80％ after purification by affinity chromatography.Western blot showed that both of the proteins were reactive with anti-HSV-1 antibody-positive sera.Conclusions Fusion expression vectors have been constructed for the gC protein,and IPTG successfully induces its expression.Moreover,the resulting proteins could react with anti-HSV-1 antibody-positive sera,and may serve as an ideal experimental material for next functional study.

Objective To analyze CT and MR imaging features of dysembryoplastic neuroepithelial tumor(DNT),so that to improve its diagnostic accuracy.Methods CT and MRI fidnings of DNT in 10 cases proved surgically and pathologically were retrospectively reviewed.Results All lesions were located in the super-tentorial gray matter regions or involved the cererbral certex mainly.The lesions were round,lobular,triangular or irregular pseudocystic masses with definite borders mostly.The lesions were hypointense on T_1WI and hyperintense on T_2WI.On fluid attenuated inversion recovery weighted images,the hyperintense "ring sign" and septa of the lesions were seen.On diffuse-weighted images(DWI),the lesions were hypointense or slight hypointense.On MR spectroscopy,NAA of the lesions slightly decreased.There were no peripheral edema and mass effect with well-demarcated.7 lesions had no enhancement and 3 lesions had slight unhomogeneous enhancement after administration of contrast medium.The lesions in 2 cases on plain CT showed low attenuation and one had calcification inside the lesion.Conclusion DNTs are of typical neuroradiologic features,that may be helpful for the diagnosis of which preoperatively.