OBJECTIVETo evaluate the effect of microwave sintering on the translucency of zirconia and to compare these effect with those of conventional sintering. The relationship between the microstructure of specimens and translucency was investigated.

METHODSA total of 10 disc-shaped specimens were fabricated from 2 commercial brands of zirconia, namely, Zenostar and Lava. Each group included 5 discs. Conventional sintering was performed according to the manufacturers' specifications. The maximum temperature for Zenostar was 1,490 °C, whereas that for Lava was 1,500 °C. The dwelling time was 2 h. The sintering temperature for microwave sintering was 1,420 °C, heating rate was 15 °C · min⁻¹, and dwelling time was 30 min. After sintering, the translucency parameter (TP) of the specimens were measured with ShadeEye NCC. The sintered density of the specimens was determined by Archimedes' method. The grain size and microstructure of the specimens were investigated by scanning electron microscopy.

RESULTSDensity and translucency slightly increased by microwave sintering, but no significant difference was found between microwave and conventional sintering (P > 0.05). Small and uniform microstructure were obtained from microwave sintering. The mean TP of Lava was significantly higher than that of Zenostar (P < 0.001).

CONCLUSIONThe translucency of zirconia sintered by microwave sintering is similar to that of the zirconia sintered by conventional sintering.

Ceramics ; chemistry ; Dental Prosthesis Design ; methods ; Heating ; Materials Testing ; Microscopy, Electron, Scanning ; Microwaves ; Surface Properties ; Technology, Dental ; methods ; Zirconium ; chemistry

BACKGROUND: Retinitis pigmentosa (RP) is a non-inflammatory, bilaterally progressive, retinal degeneration characterized by loss of photoreceptor cells via an apoptotic mechanism, and it eventually leads to blindness.Research shows that the traditional Chinese medicines of Astragalus has great prospect on blocking the progression of RP disease.OBJECTIVE: To observe the protective effect of Astragalus on N-methylN-nitrosourea (MNU)-induced retinal damage in Sprague-Dawley (SD) rats and provide the optimal treatment for RP in humans.DESIGN: Randomized controlled experiment.SETTING: School of Pharmaceutical Sciences, Xinxiang Medical College.MATERIALS :The experiment was completed in Pharmacological Laboratory of Zhongshan Ophthalmic Centre, Sun Yat-sen University between March to December 2004. Totally 114 female SD rats were purchased from the Animal Center of Zhongshan Medical College, Sun Yat-sen University.MNU was purchased from Sigma Company of America. Astragalus injection was purchased from Chengdu Diao Jiuhong Pharmaceutical Factory (Batch No. Z99060535, 2 mL/ampoule, main ingredient: Astragalus).METHODS: Among 114rats, 30 were for morphometric analysis of retinal layers, 30 were for detection of apoptosis and 54 were for detection of NF-κB p65 activity. All of them were randomly divided into different groups and each group had 6 rats. Astragalus at doses of 2.5, 5 and 10 g/kg were injected intraperitoneally into 47-day rats once a day. Meanwhile, a single intraperitoneal injection of 60 mg/kg MNU was given to 50-day rats in model and Astragalus groups. At different intervals after MNU treatment,the animals were sacrificed. Retinal damage was evaluated based on retinal thickness, the apoptotic index of the photoreceptor cells was detected by TUNEL labeling and the DNA-binding activity of NF-κB p65 was analyzed according to transcription factor assay kit.MAIN OUTCOME MEASURES: Comparison of retinal thickness, apoptotic index and the activity of nuclear NF-κB p65.RESULTS: Totally 114 rats entered the result analysis. Pretreatment with Astragalus could dose-dependently suppress MNU-induced photoreceptor cell loss and decreased the apoptotic index. Astragalus at dose of 10 g/kg also time-dependently up-regulated the activity of nuclear NF-κB p65.However, protective effect of Astragalus on MNU-induced central retinal damage was not found.CONCLUSION: Astragalus partially protects against MNU-induced retinal damage by up-modulating the activity of nuclear NF-κB p65 to inhibit apoptosis of photoreceptor cells in a dose-dependent manner.

ObjectiveTo investigate the effect of intrathecal (IT) Ro25-6981 (a selective NR2B receptor antagonist) on focal cerebral ischemia-reperfusion (I/R) injury in rats.MethodsSixty healthy male SD rats weighing 280-320 g in which IT catheter was successfully implanted without complication were randomly divided into 4 groups ( n ＝ 15 each):group sham operation (group S) ; group focal cerebral I/R(group I/R) ; group I/R + Ro25-6981 (group Ro) and group I/R+ normal saline (group NS).The right middle cerebral artery was occluded for 2 h with a nylon thread with rounded tip which was inserted into right internal carotid artery and advanced cranially until resistance was met in groups I/R,Ro and NS.In group Ro Ro25-6981 100 μg/10 μl was injected IT at 0,2,23 h of reperfusion,while in group NS NS was injected IT instead of Ro25-6981.Neurological dificit was assessed and scored (0 ＝ no deficit,3 ＝ severe deficit) at 24 h of reperfusion.The infarct size was determined by 2,3,5-triphenyl tetrazolium chloride staining.ResultsIT administration of Ro25-6981 significantly reduced cerebral I/R-induced infarct sized and neurological deficit score in group Ro as compared with groups I/R and NS.ConclusionRo25-6981 injected IT can protect the brain against local cerebral I/R injury.

Objective To investigate the expression and significance of Rho-associated protein kinaseⅡ(Rock Ⅱ)in preeclamptic placenta and umbilical artery.Methods Semiquanfitative RT-PCR and Western blot were used to investigate the expression of RockⅡmRNA and RockⅡprotein in placenta and umbilical artery from 35 women with moderate preeclampsia(MPE group)、38 women with severepreeclampsia(SPE group)and 45 normal third trimester pregnant women(control group),the S/D value of umbilical artery was examined by ultrasound.Results (1)The expression of Rock Ⅱ mRNA of Dlacenta in MPE group(0.82±0.14)and SPE group(0.93±0.13)were signifieantly higher than that in control group (0.70 ±0.12,P＜0.01).The expression of Rock Ⅱ protein of placenta in MPE group(0.79±0.15)and SPE group(0.92±0.12)were significantly higher compared with control group(0.68±0.11,P<0.01).The expression of Rock Ⅱ mRNA and protein of placenta in SPE group were higher compared with MPE group(P＜0.01).(2)The expression of Rock Ⅱ mRNA of umbilical artery in MPE group(0.69±0.13)and SPE group(0.55±0.12)were significantly lower than that in control gmup(0.76±0.10,P＜0.01).The expression of RockⅡ protein of umbilical artery in MPE group(0.68±0.10)and SPE group(0.51±0.12)were lower compared with control group(0.75±0.13,P＜0.01).The expression of RockⅡ mRNA and protein of umbilical artery in SPE group were significantly lower compared with MPE group(P＜0.01).(3)There were no correlations between the expression of RockⅡ mRNA and protein in placenta and umbilical artery and the S/D value and birth weight(P＞0.05).Conclusion The upregulated expression of Hock Ⅱ in placentas and downregulated expression in umbilical artery may be a compensation in preeclampsia.

Objective To investigate the effect of dexmedetomidine postconditioning on acute lung injury (ALI) induced by lipopolysaccharide (LPS) in rats.Methods Fifty male Spragne-Dawley rats,aged 7-8 weeks,weighing 200-250 g,were randomly divided into 5 groups (n =10 each) using a random number table:control group (group C),LPS group and postconditioning with 3 different doses of dexmedetomidine groups (LD,MD and HD groups).ALI was induced with LPS 8 mg/kg injected via the caudal vein in LPS,LD,MD and HD groups.Dexmedetomidine 5,10 and 15 μg/kg were injected intraperitoneally in LD,MD and HD groups,respectively,at 1 h after LPS injection.The equal volume of normal saline was injected intraperitoneally in C and L groups.Blood samples were taken from the left ventricle at 6 h after dexmedetomidine administration,then the animals were sacrificed and broncheoalveolar lavage fluid (BALF) was collected.The concentrations of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in plasma and BALF were detected by ELISA.The lungs were removed for microscopic examination of pathological changes and for determination of wet/dry lung weight (W/D) ratio and expression of Toll-like receptor 4 (TLR4) mRNA (by RT-PCR) in lung tissues.Results Compared with group C,W/D ratio,pathological scores,and the concentrations of IL-6 and TNF-α in plasma and BALF were significantly increased,and the expression of TLR4 mRNA was up-regulated in LPS,LD,MD and HD groups.Compared with LPS and LD groups,W/D ratio,pathological scores,and the concentrations of IL-6 and TNF-α in plasma and BALF were significantly decreased,and the expression of TLR4 mRNA was down-regulated in MD and HD groups.There was no significant difference in the parameters mentioned above between LPS and LD groups,and between MD and HD groups.Conclusion Dexmedetomidine postconditioning can alleviate ALI induced by LPS in rats,and up-regulated TLR4 mRNA expression and reduced inflammatory responses may be involved in the mechanism.

Objective To construct extravillous trophoblast(EVCT) tissue microarray and detect the expression of phosphorylated signal transducer and activator of transcription 3 (pStat3) in EVCT and to explore the role of Stat3 signal transduction pathway in the pathogenesis of preeclampsia.Methods Placentas of 80 pregnant women with preeclampsia and 58 normal pregnant women hospitalized in the Third Affiliated Hospital of Zhengzhou University from December 12,2007 to December 31,2010 were recruited for constructing EVCT tissue microarray.Vimentin,cytokeratin and human leukocyte antigen-G were used to verify EVCT tissue microarray immunohistochemically.The difference of pStat3 expression was detected between preeclampsia patients and normal pregnant women by immunohistochemical staining.Rank sum test,Kruskai-Wallis H test,t-test and Chisquare test were used for statistical analysis.Results Placental tissues from 57 preeclampsia patients (109 tissue cores) and 31 normal pregnant women (65 tissue cores) were suitable for constructing EVCT tissue microarray.The target tissue was positive for both cytokeratin and human leukocyte antigen-G staining and negative for vimentin,which was in accordance with the characters of EVCT tissue.Totally 86.4％(76/88) samples retained the target EVCT tissues,which meant EVCT tissue microarray was constructed successfully.The expression of pStat3 was significantly decreased in EVCT of preeclampsia patients (51.1％,24/47),the early onset (50.0％,19/38) and severe preeclampsia patients(52.3％,23/44) as compared to normal pregnant women (72.4％,21/29) (U=492.00,473.00 and 401.00,P＜0.05 respectively).Conclusions EVCT tissue microarray has been successfully constructed,and could be used to detect pStat3 expression.pStat3 signal transduction pathway may be involved in the development of preeclampsia.

Objective To evaluate protective effects of hypothermic pulmonary protective solution with uli-nastatin on lung function during cardiopulmouary bypass (CPB) in the patients with congenital heart disease(CHD) and pulmonary hypertenion. Method Fifty-four children,who had CHD of left-to-fight shunts with moderate-se-rious pulmonary hypertension, were enrolled. They had been performed with the radical operation under CPB from September 2005 to December 2006 in the Department of Cardiovascular Surgery, Children' s Hospital of Zhejiang University. Moderate-serious pulmonary hypertension was defined as pulmonary-to-systolic pressure ratio > 0.45(Pp/Ps > 0.45). Fifty-four children were randomly divided into three groups. Patients in group A (n = 18)didn't receive pulmonary protective solution, and scrved as control; patients in group B (n = 18) were adminis-tered with pulmonary protective solution without ulinastatin;patients in group C (n = 18) were administered with pulmonary protective solution with ulinastatin. The serum concentrations of MDA and MPO were measured at five different time points:pre-operation, 0 h, 3 h, 6 h and 24 h in the intensive care unit (ICU) (T1～5). Patients'lung functions were monitored at T1 - T4. The time of mechanical ventilation was recorded. Results No one died in this study. The mean time of mechanical ventilation was shorter in the group B and group C than that in the group A. The MDA and MPO levels were lower in group B compared with group A at T4. The MDA level at T3-T5 and the MPO level at T4 was lower in group C than those in group A. There were no significant in MDA and MPO levels between group B and group C at five time point.A-aDO2 was lower in groups B and C than those in group A at T3 and T4, whereas at T4, A-aDO2 was lower in group C than that in group B. Cdyn was higher in group B at T3and group C at T3 - T4 than those in group A. Cdyn was lower in groups C than that in group B at T4.Condusions Lung perfusion with hypothermic protective solution during CPB can all lung injury and promote recovery after operation, especialy with ulinastatin.

OBJECTIVE To investigate the bone development activity and differences in safety of ethanol extract (EE) and water decoction (WD) of Psoralea corylifolia L.efficiently.METHODS Zebrafish larvae were co-exposed to prednisolone 25 μmol· L-1 and different concentrations of EE and WD (0.1,1.0,10 and 100 mg crude drug· L-1),and etidronate disodium (ED) 30 mg·L-1.All these groups were incubated at 28.5℃ until 9 dpf.The medium solution was changed every other day.Zebrafish skeleton at 9 dpf was stained with alizarin red and inspected under an optical microscope,in addition,the death toll and organ toxicity of zebrafish were also observed.The mRNA expression of osteoprotegrin (OPG) and receptor activator of NF-κB ligand (RANKL) in 9 dpf zebrafish were determined with fluorescence quantitative PCR.Zebrafish embryos (1 dpf) were exposed to various concentrations of EE (10,20,30,35,40,50 and 60 mg crude drug· L-1),WD (10,50,100,125,150,175,200 and 500 mg crude drug· L-1),psoralen (12.5,25.0,50.0,100.0,200.0 and 400.0 μmol·L-1) and bakuchiol (1,5,10,25 and 50 μmol· L-1).Embryonic morphology of zebrafish (3 dpf) was inspected with an optical microscope and the death toll of embryos or larvale was counted from 2 dpf to 9 dpf and LC50was calculated.Components of EE and WD ware analyzed by HPLC method.RESULTS Both EE (0.1 mg crude drug· L-1) and WD (1.0 mg crude drug· L-1) groups could increase the staining area and optical density values of zebrafish skeleton compared with prednisolone group (P＜0.01),indicating the increase in bone mineralization;the OPG mRNA expression in both EE and WD (1.0 mg crude drug· L-1) groups increased,while the RANKL mRNA expression decreased (P＜0.01) and the ratio of OPG/RANKL improved obviously (P＜0.01).Embryos exposed to EE,WD,psoralen and bakuchiol showed swelling of the heart and yalk sac,and decrease in GOT.The LC50 of WD and psoralen was 5～8 and 5～21 times that EE and bakuchiol,respectively.The composition and relative content of EE and WD also varied considerably.CONCLUSION Bone development activity and toxicity of EE are both stronger than those of WD.The lipid soluble characteristic components of Psoralea corylifolia L.,may be critical components of toxicity.

Objective To evaluate the effect of lipopolysaccharide (LPS) on the expression of ATP-binding cassette transporter A1 (ABCA1) in alveolar macrophage cells of rats.Methods The alveolar macrophage cells of rats NR8383 were seeded in 6-well plates at a density of 1 × 106 cells/ml (2 ml/well) and randomly divided into 6 groups:control group (group C,n =24),0.2 μg/L LPS group (group L0.2,n =12),2.0 μg/L LPS group (group L2.0,n =12),20.0 μg/L LPS group (group L20.0,n =60),200.0 pg/L LPS group (group L200.0,n =12),and 20.0 μg/L LPS + ABCA1 siRNA group (group L20.0 + siRNA,n =12).The cells were routinely cultured in group C.LPS with the final concentrations of 0.2,2.0,20.0 and 200.0μg/L was added to the culture medium in L0.2,L2.0,L20.0 and I200.0 groups,respectively.In group L20.0 + siRNA,siRNA 50 nmol/L was added to the culture medium and 12 h later LPS 20.0 μg/L was added.In group C,6 wells were chosen for determination of ABCA1 mRNA and protein expression.At 24 h of incubation with LPS 0.2,2.0 and 200.0 μg/L,or at 2,6,12 and 24 h of incubation with LPS 20.0 μg/L,6 wells were chosen and the cell suspension was obtained for measurement of ABCA1 mRNA expression (by real-time fluorescent quantitative PCR),and ABCA1 expression (by flow cytometry).At 12 h of incubation with 20.0 μg/L LPS or with 20.0 μg/L LPS + 50 nmol/L siRNA,6 wells were chosen and the cell suspension was obtained for measurement of TLR4 mRNA expression (by real-time fluorescent quantitative PCR) and TLR4 expression (by flow cytometry).Results Compared with group C,the expression of ABCA1 mRNA and protein was significantly down-regulated in L0.2,L2.0,L20.0 and L200.0 groups,and the expression of ABCA1 mRNA and protein was up-regulated in L20.0 and L20.0 + siRNA groups.In L20.0 group,the expression of ABCA1 mRNA and protein was gradually down-regulated with the prolonging time of incubation with LPS.Compared with group L20.0,the expression of TLR4 mRNA and protein was significantly up-regulated in group L20.0 + siRNA.Conclusion LPS can down-regulate the expression of ABCA1 in alveolar macrophage cells of rats,however,ABCA1 can inhibit the synthesis of TLR4.

Objective To observe the medium-and long-term results of one-stage debridement and total hip arthroplasty (THA) for advanced active tuberculosis of the hip.Methods From January 2002 to December 2008,8 patients (9 hips) with advanced active tuberculosis of the hip underwent one-stage debridement and THA in our hospital.There were 5 males and 3 females,aged from 18 to 59 years (average,39.6 years).According to Babhuulkar and Pande imaging classification,there were 1 case of grade Ⅲ and 7 cases of grade Ⅳ.All patients had hip pain,which got serious during active and passive motion.All patients had dysfunction in stretch,abduction,rotation and flexion of the hip,and the flexion deformity ranged from 30° to 70° (average,46°).Thomas sign were positive in all patients.The erythrocyte sedimentation rate ranged from 45 to 125 mrr/1 h.The results of tuberculin test were all positive.X-rays showed osteoclasia,narrowing or disappearance of the joint space and surrounding abscess in all patients.The diagnosis of hip joint tuberculosis was confirmed by postoperative pathological examination in all patients.All patients were treated with antituberculous medications for 12 to 18 months,including preoperative IRES (≥ 2 weeks) and postoperative IRES (3 months),IRE (6 to 9 months) and IR (3 to 6 months).Results All patients were followed up for 50 to 150 months (average,88.8 months).One-stage healing of incision was obtained in all patients.X-rays showed no signs about loosening of prosthesis and recurrence of tuberculosis.The erythrocyte sedimentation rate returned to normal range within 6 months after operation.The average Harris score improved from preoperative 25.78±16.15 to 94.78±2.91 at final follow-up,and the difference was significant.Conclusion Under the standard antituberculosis chemotherapy,the one-stage debridement and THA are safe and feasible for advanced active tuberculosis of the hip,which can result in satisfactory medium-and long-term resuits.