BACKGROUND:There are numerous studies about mechanical changes of recast cobalt-chromium ceramic al oys. However, little is reported on the mechanical properties of cobalt-chromium ceramic al oys containing once-used al oys after recasts.
OBJECTIVE:To study the effects of different proportion of once-used al oys to recasting cobalt-chromium al oys on their mechanical properties, including tensile strength, yield strength, elongation and hardness.
METHODS:Cobalt-chromium al oys cast samples were prepared and recast for three times (40%once-used al oys were added per time). The tensile strength, 0.2%yield strength, percentage of elongation, flexural strength and Vickers hardness of each specimen were measured. In addition, microscopic metal ographic observation was done.
RESULTS AND CONCLUSION:Being recast for three times, cobalt-chromiun al oys showed no significant differences on their tensile strength, 0.2%yield strength, percentage of elongation, flexural strength and Vickers hardness. GenerationⅠal oy samples had uniform size, smal diameter and smal carbide size distributing along the grain boundary, mainly exhibiting spherical and irregular wormlike forms. Generations Ⅱ and Ⅲ samples were uniform in shape, but crystal grains were coarsened a little. Carbide from Generation IV samples began to be coarsened, irregular wormlike carbides were increased in amount, and a few of non-metal ic inclusions could be found in grains. Cobalt-chromium al oys can be recast after addition of 40%once-used al oys for three times at least in air environment, without decrease of the mechanical properties.

[Objective]To investigate the characteristics and clinical results of open reduction and internal fixation for fractures of the calcaneus for earthquake patients.[Method]The fractures were classified according to Sanders classification.Fifteen cases(24 fractures) were treated by open reduction and internal fixation.Thirteen cases(21 fractures) were followed up from four,four and half months(average of 4.2 months).[Result]All fractures had been healed.Functional results were evaluated using Marryland Foot Score and excellent results occured in 9(42.9%),good in 10(47.6%),fair in 2(9.5%) and the satisfactory rate was 90.5%.Two cases of incision infection were cured by skin flap transplantation.[Conclusion]Open reduction and internal fixation is an effective method for treatment of displaced intra-articular fractures of the calcaneus.Earthquake patients are not fit for early operation.They should be treated with operation after normal functional index and stable psychological situation.

Objective To reconstitute hair follicles in mice using graft chambers,and to study the effect of different cell types on hair follicle regeneration.Methods Full-thickness skin was obtained from the back of C57BL/6 neonatal mice.Then,epidermal cell suspensions were prepared by shredding epidermis after trypsinization,hair follicles and dermal cells were collected by filtration,low-speed centrifugation and density gradient centrifugation,and hair follicle epithelial cells were obtained via trypsinization of hair follicles followed by filtration.Nude mice were classified into four groups to be transplanted with epidermal cells + follicular buds,dermal cells alone,epidermal cells + follicular buds + dermal cells,follicular epithelial cells + dermal cells,respectively.The cells were implanted into the dorsal skin of nude mice using fold chambers.After the grafting,the growth of skin and hairs was observed at the grafted sites on week 1,2,4 and 8,and skin specimens were obtained on week 2,4,and 8 for histological study of hair follicles using hematoxylin-eosin staining.Results After grafting,the chambers on the back of nude mice began to shed with crust formation on week 1; stunted hairs came out and follicle-like structures were seen under the microscope on week 2 at the grafted sites,normal hairs were observed on week 4 and 8 in all the mice except for those transplanted with epidermal cells + follicular buds,and the growth of hairs in mice grafted with epidermal cells + follicular buds + dermal cells and mice grafted with follicular epithelial cells +dermal cells was superior to that in mice grafted with dermal cells alone.Conclusions Hair follicles can regenerate after hair follicle cell transplantation into dorsal chambers in nude mice.Both epidermal cells and dermal cells play indispensable roles in hair follicle reconstitution.

Objective:To compare the clinical effects and improvement of serum hormone levels of kidney tonifying and blood circulation recipe and mirena in the treatment of perimenopasual dysfunctional uterine bleeding.Methods:92 cases of perimenopausal patients with dysfunctional uterine bleeding in our hospital from July 2013 to November 2016 were selected and divided into group A and group B with 46 cases in each group.Group A was orally administered with kidney tonifying and blood circulation recipe,and group B was administered with mirena.Both groups were treated for 3 periods.The efficacy and incidences of adverse effect in two groups were observed.The levels of serum hormones and hemoglobin (Hb),and endometial thickness (ET) were detected in two groups.The indices of serum hormone included follicle-stimulating hormone (FSH),luteinizing hormone (LH),progestone (P) and estradiol (E2).Results:No significant difference was found in the total effective rate between two groups (P＞0.05).After treatment,the levels of serum FSH,LH,E2 and P as well as ET and Hb in both groups were all significantly lower than those before treatment (P＜0.01),and the levels of serum FSH,LH,E2 and P as well as ET of group B were significantly lower than those of group A (P＜0.01),no significant difference in the Hb level between two groups (P＞0.05).The incidence of adverse reactions of group B (15.22％) was significantly higher than that of group A(0％) (P＜0.01).Conclusions:The kidney tonifying and blood circulation recipe had similar effect as mirena in the treatment of perimenopasual dysfunctional uterine bleeding,while mirena had strong improving effect in serum hormone level and ET,kidney tonifying and blood circulation recipe had higher security.

Objective To compare the changes in TLR4-NF-κB signaling pathway in infant and adult mice infected with influenza virus, and to provide experimental evidence for the study of immunopathological mechanism in pediatric respiratory virus susceptibility. Methods Immunohistochemistry and RT-PCR were applied to detect the expressions of lung TLR4 and NF-κB P65 mRNA and proteins in the infant and adult mice, and to compare the changes in TLR4-NF-κB P65 signaling pathway after infection with influenza virus.Results (1) The infant model group showed the strongest expression of TLR4 protein in the lung tissue, compared with that in the normal group and adult model group showing significant differences (P<0.05).(2) The expression of NF-κB P65 protein in the lung tissue was strongest in the infant model group, and it was gradually increased over time, showing a significant difference between each time point and the next time point (P<0.05).(3) The infant model group showed the strongest expression of TLR4 mRNA in lung tissue, significantly higher than that in the normal and adult model groups (P<0.05).(4) The expression of NF-κB P65 mRNA in the lung tissue was highest in the infant model group, and significantly higher than that in the normal and the adult model groups ( P<0.05) , and it was gradually increased with the time.Conclusions The over-activation of TLR4-NF-κB P65 signaling pathway may be one of the immunopathological mechanisms of serious injury in the lung tissue in infant rats.

Objective:To evaluate the sensitivity of the ArcCheck dosimetry system in detecting the leaf open time errors during the center and off-center helical tomotheray delivery quality assurance (DQA).Methods:Nine nasopharyngeal carcinoma (NPC) patients were selected in this study. Two DQA plans were created for each patient: the" center" plan was created by moving the image of the ArcCheck phantom to place the high dose region on the phantom center and the " off-center" plan was created by offsetting the phantom and putting several diodes through a higher does region. Leaf open time errors of 2, 4, 6, 8 and 10 ms were introduced to the Sinogram which was modified using Matlab. Each intentional error plan and original (no error) plan for each patient were measured using both " center" and " off-center" DQA methods, the γ analysis was performed to evaluate the DQA results. The different dose and distance error criteria of 3%/3 mm, 3%/2 mm and 2%/2 mm were selected, and different thresholds of 5%, 10% and 15% were selected for γ analysis. The gradient and the minimum detectable error approach were taken to quantitatively analyze the sensitivity. The correlation between different dose distance error criteria and different thresholds was also evaluated by Pearson correlation analysis. Results:The absolute value of γ gradient of the " center" DQA plans were larger than those of the " off-center" plans in all different γ criteria (all P<0.05). The stricter the γ criteria were adopted, the more sensitive DQA results of leaf open time error were obtained. The minimum detectable error was 2 ms in all different γ criteria for the " center" DQA plan. The minimum error detectability of the " off-center" DQA plan was weaker than that of the " center" DQA plan. The γ passing rates of three different dose distance error criteria were significantly strongly correlated for the " center" DQA plan ( R2>0.9). For the " off-center " DQA plan, only the 3%/3 mm and 3%/2 mm criteria were significantly strongly correlated ( R2>0.9). Significant strong correlation was observed in the γ passing rate at different thresholds between the " off-center" and " center" DQA plans. Conclusions:The " center" DQA plan method is more sensitive than the " off-center" DQA plan method in all γ criteria, and the γ passing rates in different γ criteria are strongly correlated for the " center" DQA plan. The " center" DQA plan method is recommended.

Objective:To compare the leaf open time (LOT) parameters and γ passing rates between the 4.0.4 and 4.2.3 helix Tomotherapy planning systems and evaluate the improvement.Methods:Retrospective comparison of the treatment plans of 345 cases selected by 4.0.4 and 4.2.3 versions was performed. The Machine Specific Sinogram of each plan was extracted from the archived plan file to calculate the LOT. The evaluated LOT parameters included the projection time, the maximum LOT, the mean non-zeros time, the time difference between the projection time and the maximum LOT, the relative count of leaves with LOT greater than maximum LOT minus 5 ms, the relative count of leaves with LOT lower than 100 ms and the beam on time. The γ passing rate (criteria: 3 mm/3%, 10% threshold and global error) and the LOT parameters between two version systems were evaluated with the independent t-test. The relationship between the LOT parameters and γ passing rate was analyzed by the multiple linear regression method. Results:The γ passing rate of the Ver 4.0.4 system was 97.86%, significantly lower than 98.6% of the Ver 4.2.3 system ( P<0.001). The time gap between the projection time and the maximum LOT of the Ver 4.2.3 system was significantly less than that of the Ver 4.0.4 system (1 ms vs. 11 ms, P<0.001). For the Ver 4.0.4 system, the multiple linear regression method showed that the maximum LOT ratio and the beam on time were negatively correlated with the γ passing rate (both P<0.001). However, for the Ver 4.2.3 system, only the beam on time showed a negative correlation with the γ passing rate ( P<0.001). Conclusion:The γ passing rate of the Ver 4.2.3 system is significantly higher than that of the Ver 4.0.4 system. The decrease of γ passing rate caused by the leaves near the maximum LOT is properly resolved in the new version system.

AIMTo analyze gene expression difference between human mesenchymal stem cells and umbilical vein endothelial cells, to discuss the feasibility of inducing hMSCs to differentiate into endothelial cells through in vitro gene transfection as well as the use and prospective as a seeding cell source of vascular tissue engineering.

METHODShMSCs and hUVECs were isolated, expanded in culture, and characterized by flow-cytometry, immunocytochemistry, immunofluorescence and transmission electron microscopy (TEM). Differential analysis of gene expression profiles between them was performed by Biostar H-40 cDNA microarrays. The properties of VEGF 165 transfected were also detected with RT-PCR, ELISA et al.

RESULTSNearly 86% genes were coexpressed in both cells and hMSCs expressed typical endothelial antigen marker of EC. After VEGF165 transfection, hMSCs (or committed hMSCs) were positive for CD31. To different extent, the expression of CD44 was down regulated and CD34, FVIIIAg, Flt-1 up regulated.

CONCLUSIONGeneration of functional EC or tissue engineered blood vessels from human MSCs is feasible utilizing an in vitro environment gene transfection.

Bone Marrow Cells ; cytology ; Cell Differentiation ; Cells, Cultured ; Endothelial Cells ; cytology ; Endothelium, Vascular ; cytology ; Humans ; Mesenchymal Stromal Cells ; cytology ; Transfection ; Vascular Endothelial Growth Factor A ; administration & dosage

OBJECTIVETo observe the effect of synchronous perfusion of specific respiratory chain complex IV inhibitor sodium azide (NaN3) in brain on rat ventromedial prefrontal cortex (mPFC) and acetylcholine (ACh) and choline (Ch) contents in hippocampal extra-cellular fluid, and establish the AD rat model induced by mitochondrial acute injury.

METHODThe synchronous dual-probe dual-channel brain microdialysis sampling technology was applied to synchronously perfuse modified Ringer's solution containing NaN3 (50 micro mol L-1) and neostigmine (2 micro mol L-1) into mPFC and hippocampus of conscious, freely moving normal rats, and continuously collect dialysates from different encephalic areas. Dynamic contents of ACh and Ch were determined by high performance liquid chromatography-post-column immobilized enzyme reactor-electrochemical process.

RESULTACh and Ch contents in mPFC extracellular fluid of normal rats were higher than that in hippocampus. During the process of perfusion, NaN3 could significantly reduce ACh in mPFC/hippocampal extra-cellular fluid, but remarkably increase Ch, and constantly inhibit the recovery of ACh and Ch contents in mPFC/hippocampus.

CONCLUSIONThe synchronous perfusion of NaN3in rat mPFC and hippocampus can injure functions of the cholinergic nerve projection area, and cause the acute AD model with ACh and Ch metabolic disorders. This model can be used in pathogenetic and pharmacological studies.

Acetylcholine ; metabolism ; Animals ; Choline ; metabolism ; Extracellular Fluid ; drug effects ; metabolism ; Hippocampus ; cytology ; Male ; Neurotransmitter Agents ; metabolism ; Perfusion ; Prefrontal Cortex ; cytology ; Rats ; Rats, Sprague-Dawley ; Sodium Azide ; administration & dosage ; pharmacology ; Time Factors

Objective To observe the effect of sodium butyrate on the invasion and migration of human salivary gland ade‐noid cystic carcinoma cell line ACC‐2 in vitro and to investigate the underlying mechanisms .Methods The cultured ACC‐2 cells were treated with different concentrations of sodium butyrate for 24 h ,and detected the viability rate of the cells by methyl thiazolyl tetrazolium(MTT) assay ;the drug′s influence on invasion and migration on ACC‐2 were detected by Transwell experiment ,while the protein and mRNA expression of HMGB1 and TLR4 explored by Western‐blot and RT‐PCR assay ;the relationship between TLR4 expression and HMGB1 was investigated .Results Compared with control group ,0 .625 ,1 .250 ,2 .500 ,5 .000 ,10 .000 mmol/L groups of sodium butyrate inhibited the proliferation of ACC‐2 cells(P<0 .05);the influence of sodium butyrate on the in‐vasion of ACC‐2 cells of all groups had no significant difference(P>0 .05);only 2 .500 ,5 .000 and 10 .000 mmol/L groups inhibited ACC‐2 cells migration and down‐regulated the protein and mRNA of HMGB1 and TLR4(P<0 .05) .Correlation analysis showed a positive correlation between the TLR4 protein and HMGB1 protein(r=0 .810 ,P<0 .05) .Conclusion Sodium butyrate could inhib‐it ACC‐2 cells proliferation and high concentration gropes inhibit ACC‐2 cells migration ,while reducing HMGB1 and TLR4 mRNA and protein expression ,suggesting that NaB might inhibite ACC‐2 cells migration through down‐regulated the mRNA and protein expression .