The incidence of thyroid dysfunction has increased year by year; the degree of public concern about thyroid disease also has been growing; the accuracy and comparability of results given by thyroid hormone assays from clinical laboratories face new challenges .This paper reviewed the clinical significance and measurements of thyroid hormones , also summarized the outcome of IFCC Working Group on Standardization of Thyroid Function Tests .It is expected to bring manufacturers′and clinical laboratories′attention to the importance of standardization/harmonization; and they could collaborate with each other .

Objective:To prepare poly-L-lactic acid(PLLA)electrospun nanofibers carrying icariin(ICA)(ICA /PLLA)and to evaluate the effects of the ICA /PLLA on MC3T3-E1 cells.Methods:ICA solution was dispersed into PLLA solution,and electrospun fibers were fabricated by W/O emulsion method.The morphology of ICA /PLLA was observed by SEM.The in vitro release kinetics of ICA /PLLA was examined.The attachment of MC3T3-E1 cells on ICA /PLLA was examined by propidiumiodide(PI)labling and ob-served under fluorescent microscope.The proliferation of the cells was measured by MTT assay.The differentiation of the cells was ob-served by alkaline phosphatase (ALP)assay.Results:In vitro,ICA was effectively released from ICA /PLLA for 22 days,cells were attached well on the surface in all groups,ICA did not affect the proliferation of MC3T3-E1 cells(P >0.05),but increased the ALP activity(P <0.05)of the cells.Conclusion:ICA /PLLA can effectively control the release of ICA and promote the differentiation of MC3T3-E1 cells.

BACKGROUND:There is often space between implant and bone during immediate implantation.Whether biological membrane is needed to guide bone regeneration remains poorly understood.OBJECTIVE:To createdifferent sizes of space between femurand implantsindogs and to observe the effects of biological membrane on bone regeneration capacity of bone defects surrounding implants.DESIGN,TIME AND SETTING:A self-control animal experiment was performed at the Laboratory Animal Center,Norman Bethune College of Medicine,Jilin University and School of Stomatology,Jilin University between March and December 2005.MATERIALS:BLB hydroxyapatite-coated implant was provided by Beijing Leiden Biomaterial Co.,Ltd.,China;BME-10X collagen membrane was purchased from Fujian Better Biotechnology Co..Ltd.,China.METHODS:BLB implants were installed in the bilateral proximal femoral bone to create standard gradient bone defects with horizontal width 3 mm.vertical depth 5 mm,and horizontal lengths of 0,1,2,3,and 4 mm Bone defects on the left femur were sutured directly and those on the right femur were covered with biological membrane prior to suture.All animals were sacrificed at 3 months after surgery.Specimens containing implants were harvested to prepare tissue blocks for radiological observation.MAIN OUTCOME MEASURES:The quantity,color,and texture of newly formed bone surrounding implants were observed from the surface and profile levels.The implant-bone integration and new bone formation were also examined by soft X-ray photography.RESULTS:Grossobservation results revealed that when the horizontal length of bone defect was 3 mm or less,there was no significant differenee in bone density between the newly formed bone and the host bone no matter whether biological membrane existed or not;when the horizontal length of bone defect was 4 mm the bone density was better when biological membranes were used than not.Soft X-ray photography results revealed that when the horizontal length ofbone defect was 3 mm or less.no significant difference in bone density and bone trabecular morphology and orientating was found between newly formed bone and host bone no matter whether biological membrane was used or not;in the 4-mm-length bone defect areas.implants contacted with newly formed bone directly,but the calcified degree ofnewly formed bone was poor,bone trabecula was thin,and bone trabecular course was irregular,nevertheless,the calcified degree of newly formed bone was better under the condition of being with biological membrane than without biological membrane.CONCLUSION:Biological membrane exhibits strong capacity to promote the regeneration and repair of bone defect tissue with a horizontal length of 3 mm or less,and plays an important role in repatr of large sizes of bone detect

Objective To study the influence of different implant diameters on the implant-bone-interface stress distributions in zygomatic implant denture and illustrate the correlation between implant diameter and long-dated success rate of zygomatic implant denture.Methods Three-dimensional finite element model for maxilla and zygoma was established biomechanically in this study by spiral CT technique and finite element software technique,and zygomatic implant was simulated into the model in the first-maxillary-molar region.Zygomatic-implant-denture load cases concerning different implant diameters(3.5,4.0 and 5.0 mm) were designed and loaded vertically,obliquely.The implant-bone-interface stress distributions were analyzed by 3-D finite element method.Results The model could be observed from any angle,and had good geometric similarity compared with CT image.Stress peak values among these load cases with different diameters were compared,the load case with 3.5 mm diameter appeared the largest stress peak value,the load case with 4.0 mm diameter appeared the larger stress peak value and the load case with 5.0 mm diameter appeared the least stress peak value.As the implant diamater increased(3.5 mm→4.0 mm→5.0 mm),the compressive and tensive stress peak values of implant-bone interface in the maxillary alveolar ridge and the zygomatic area near maxillary sinus roof decreased gradually,the stress of implant-bone interface in the maxillary alveolar ridge was significantly larger than that of implant-bone interface in the zygoma area and compressive stress peak value was larger than tensive stress peak value.Conclusion The implant-bone-interface stress distributions tend towards uniformity as the implant diameter increases.Select wider-diameter implant as possible as the residual bone permitted clinically.

Objective:To observe the bone regeneration capacity of bone defects around BLB implants covered with or without membranes.Methods:Implants were installed into femoral bone of grown-up dogs.Near implants,3 mm horizontal width,5 mm vertical depth and 1,2,3,4 mm horizontal length(along the macroaxis of femoral bone) standard gradient bone defects were made.On one side,the incisions were directly sutured by lamination,and on the other side the incisions were sutured by lamination after using collagen membrane to cover on the defects.Three months after the operation the specimens were observed by stereomicroscopy.Results:In the groups with 1,2 and 3 mm defects,the defect areas had been filled completely with new bone which was mainly compact cortex.In the group with 4 mm defects,the defect areas were filled with new bone which was mainly trabecular bone.Bigger lacunes could be observed in the groups without membranes.Conclusion:If the defect is less than 3 mm,whether bioresorbable collagen membrane is used or not,osseointegration is well in the implant-bone interface.Improving bone regeneration should be done when the bone defect extension is bigger.

Objective:To compare the effect of three different titanium alloy surface topographies on the biological character fibro-blasts.Methods:Three different titanium alloy Ti6Al4V surface topographies were created by machining(M),direct current electro-chemical etching(DC)and alternating current electrochemical etching(AC)respectively,and standard sized samples were prepared. The surface topographies were observed field emission scanning electron microscopy(FE-SEM).Mouse L929 fibroblasts were cultured on different surfaces.The attachment of cells was examined by acridine orange staining and observed under fluorescent microscope.The proliferation of cells was measured using MTT assay.Results:Tubles with the diamete of 5 -20 μm were observed on the surface of the sample of group DC,and more evenly distributed tubles on that of group AC.Micro-sulci were observed and no microtuble was found on the sample surface of group M.L929 cells were attached on the surface of all the samples in the 3 groups.More adhered and better strached cells were observed on AC treated surface.The proliferation of fibroblasts on AC and DC surfaces was superior to that on M treated surface and at the 3 -5 day the proliferation of fibroblasts on the AC surface was higher than that on DC treated surface.Con-clusion:AC treated surface with the micro-submicro-nano hierarchical topography of titanium alloy has a superior biocompatibility and can promote the early attachment and proliferation of the fibroblasts.

Objective:To determin the effect of PLGA microspheres loading with PTH(1 34)[PTH(1 34)/PLGA]on the differentiation of MC3T3E1 cells.Methods:MC3T3E1 cells were divided into control group,continuous or intermittent PTH(1 34)adminstration groups,PLGA microsphere group and PTH(1 34)/PLGA group.Osteogenesis differentiation was observed by alkaline phosphatase activity(ALP),alizarin red staining and RTPCR.Results:The PTH(1 34)/PLGA with 1 0 -9 mol/L final release concentration enhanced ALP activity and mineralization,increased the mRNA expression of RUNX2,ALP and VEGF.Conclusion:Controlledrelease of PTH(1 34)from PLGA microspheres can promote the osteogenesis differentiation of MC3T3E1 cells.

Objective Preparation of aqueous reference materials for cholesterol and glycerol.Methods Study on reference materials.The certified reference materials GBW09203b and GBW09149 were weighed accurately and dissolved into 20% of methyl cyclodextrin aqueous solution to prepare six kinds of candidate reference materials of cholesterol and glycerol according to the concentration.The materials were tested for homogeneity and stability using routine methods.The reference methods of isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) were used to determine the concentration of cholesterol and glycerol to evaluate the accuracy of the certified values.Meanwhile, the blank verification test was carried out.The expanded uncertainty was the combination of standard uncertainty of measurement, unhomogeneity and instability.Results It showed that the six candidate reference materials were homogeneous and stable for at least 1 year at-70 ℃ and-20 ℃.The certified values (reference value ± expanded uncertainty,mmol/L) were as follows,for cholesterol:0.65±0.01,1.31 ±0.01,2.57±0.02,5.21±0.06,7.71±0.08,10.24±0.06;for glycerol:0.29±0.01,0.58±0.01,1.22±0.02,2.24±0.02,3.46±0.04,4.52 ±0.04.The results of reference methods were consistent with the certified values.Blank validation tests showed that the concentration of the analytes would not be affected by the reagent and the blank matrix.Conclusions Certified reference materials for cholesterol and glycerol in aqueous solution have been prepared successfully.These materials are homogeneous and stable, and the certified values are reliable.Therefore the materials have been approved to be the Certificate Reference Materials of GBW 09823, GBW 09824, GBW 09825, GBW09826, GBW09827 and GBW 09828.

Objective To prepare the serum reference materials for total thyroxine .Methods Individual blood samples were collected from 13 healthy donors (7 males and 6 females) aged from 20 to 50 years old, and the sera were separated and mixed into 4 serum pools according to the concentration of thyroxine.The materials were tested for homogeneity and stability using routine methods .The method of isotope dilution liquid chromatography tandem mass spectrometry ( ID-LC/MS/MS) was used to determine the concentration of thyroxine .The candidate reference materials were also measured by four conventional methods to analyze the commutability of the materials .Results It showed that the four candidate reference materials were homogeneous and commutable in four conventional methods and they were tested to be stable for at least 1 year at -70 ℃using the isochronous stability study .The certified values ( reference value ± expanded uncertainty ,nmol/L) were:75.9 ±1.8,105.3 ±2.2,114.7 ±2.1 and 187.4 ±2.9.Conclusions Certified reference materials for serum thyroxine have been prepared .These materials have been approved to be the Certificate Reference Materials of GBW 09127,GBW 09128,GBW 09129 and GBW 09130.

Objective To evaluate the effect of parathyroid hormone(1-34) [PTH(1-34)] and coralline hydroxyapatite(CHA) on bone regeneration of peri-implant bone defects.Methods Two implant sites were prepared on both sides of tibia in 8 mongrel dogs.The bone defect was created along one bone wall of each implant site.Implants were implanted into the implant sites,then CHA was grafted into the bone defects.After surgery,the animals were randomly divided into two groups.PTH(1-34) (40 μg/kg) was used for subcutaneous injection to the experimental group for three consecutive days,meanwhile the same amount of saline was given to the control group.Half of the animals of each group were sacrificed after 4 weeks and 8 weeks respectively.Specimens were subjected to implant pull-out strength tests,X-ray picture and histological observation.Results The bone density of bone defects in the experimental group were higher than that in the control group.No low-density images was observed between the implants and bone at 4 weeks and 8 weeks.The maximum pull-out force value of the experimental group(199.8 N,411.5 N) was higher at 4 weeks and 8 weeks than that of the control group(100.1 N,184.5 N) (P＜0.05).The pull-out force value of the experimental group at 4 weeks and the pull-out force value of the control group at 8 weeks were similar.The new bone trabecular around CHA of experimental group was thicker at 4 weeks.Implant surface contacted to the new bone directly without fiber.CHA granules of the experimental group at 8 weeks were fewer than that of the control group.New bone tissue of the experimental group was denser.The contact area between implant surface and new bone was wider in experimental group than in the control group.Conclusions PTH(1-34) and CHA can promote bone regeneration of peri-implant bone defects,shorten the implants and bone healing cycle and improve the implants osseointegration.