Objective: To test the mechanical properties o f N48 NdFeB magnet.Methods:Samples of N48 NdFeB magnet in the size of 2 mm?3 mm?4 mm were prepared, the residual flux density,coercive force and maximum energy product of the samples were measured, the magnetic density aroun d the magnets,the attractive and repulsive force between two magnets in 0~10 mm air gap were investegated.Results:The residual flux density of t he N48 NdFeB magnet was 1.373 T, coercive force 1 037 A/m and maximum energ y product 368 kJ/m 3.The magnetic density at magnet surface was 0.338 T,it decr eased to 0 at the point that leave magnet surface 20 mm away. The highest attrac tive force was 4.47 N between two magnets, the attractive force was 4.47~0.39 N in 0~5 mm air gap.The highest repulsive force was 2.82 N and the repulsive force was 2.82~0.39 N in 0~5 mm air gap.Conclusion:The magnetic and m echanical properties of the N48 NdFeB magnet can meet the standard of the orthod ontic force.

BACKGROUND:Preliminary experiments have demonstrated that rat liver homogenate supernatants can induce the morphological changes of human umbilical cord mesenchymal stem cells. However, little is known about whether the induced cells have some phenotypic and functional features of hepatocytes.
OBJECTIVE:To investigate whether human umbilical cord mesenchymal stem cells have some phenotypic and functional characteristic of hepatocytes after being induced by liver homogenate supernatants.
METHODS:Passage 3 human umbilical cord mesenchymal stem cells were used and divided into control group (cells were cultured in basic culture medium) and liver homogenate supernatant group (cells were cultured in liver homogenate supernatants for 3, 5, 7 days). Meanwhile, positive control group (QSG-7701 human liver celllines) and negative control group (simple liver homogenate supernatants) were set up. The protein and mRNA level of hepatocyte markers, alpha-fetoprotein, cytokeratin 18 and tryptophan 2,3-dioxygenase enzyme, were detected at different time points.
RESULTS AND CONCLUSION:After inducement, the stem cells of fusiform shape began to lose their sharp edges and progressively shrunk, and then they changed into hepatocyte-like cells with the morphous of triangle, polygon and anomalism shape. Compared with the control group, the protein and mRNA level of alpha-fetoprotein, cytokeratin 18 and tryptophan 2,3-dioxygenase enzyme significantly increased time dependently after inducement with liver homogenate supernatants (P<0.01). This study demonstrated that human umbilical cord mesenchymal stem cells are able to differentiate into hepatocyte-like cells in vitro that possess some functions of liver cells.

Objective:To investigate the effects of titanium spcimens with different surface character on the proliferation and mRNA expression of IL-6 and Cbfα1 in osteoblasts.Methods:Titanium surface was treated by smooth pretreatment(PT),sandblast and acid etch(SLA)and anodic oxidation(AD)respectively.The morphology and the elements analysis of the spcimens were inspected and detected by SEMand EDS.The surface contact angle was measured by contact angle meter.MC3T3-E1 cells were cultured on the titanium surface and cells cultured on tissue culture plate were served as the control group.The proliferation was measured by MTT assay.The mRNA expression of IL-6 and Cbfα1 was quantified by RT-qPCR.Results:The sample surface in PT group showed scrat-ches,in SLA group showed multiple three dimensional structure,in AD group exhibited porous structure.The elements of the sample surface of group PT,SLA and AD were Ti,Ti/Al and Ti/O respectively;the contact angles were 54.47°±3.33°,75.42°±8.32° and 38.91 °±4.00°respectively(P<0.05).The cells in AD group showed higher proliferation than those in PT and SLA groups(P<0.05).In AD group IL-6 mRNA expression decreased and Cbfα1 mRNA increased more than in PT and SLA groups(P<0.05). Conclusion:Titanium spcimens treated with AD may promote cell proliferation,decrease IL-6 mRNA expression and increase Cbfα1 mRNA expression in MC3T3 cells.Implats treated with AD might have some advantages in early osseointegration.

BACKGROUND:Studies have confirmed that nicotine affects the activity of osteoblasts, osteoclasts, fibroblasts and erythrocytes.
OBJECTIVE:To study the nicotine effects on osseointegration and the expression of osteoprotegerin and bone morphogenetic protein 2 after implantation of dental implants with surface treatment by sandblasting or acid etching.
METHODS:Twenty-four Sprague-Dawley rats were randomly assigned to two groups and received daily injections for 2 weeks as folows: Nicotine 2 mg/kg twice for experimental group, saline solution for control group. Then the titanium implants with surface sandblasting or acid etching were implanted into the tibiae folowed by continuous nicotine or normal saline injection. At weeks 2 and 4 after implantation, the implants and surrounding bone tissue were prepared for CT, X-ray and hematoxylin-eosin staining examinations to evaluate bone healing and expression levels of bone-related genes were measured by quantitative RT-PCR.
RESULTS AND CONCLUSION: Compared with the control groups, the degree of osseointegration and the expression of osteoprotegerin and bone morphogenetic protein 2 in the experimental groups were decreased significantly (P < 0.05), except that the expression of bone morphogenetic protein 2 in the experimental group with acid etching was not significantly reduced. In addition, the expression of bone morphogenetic protein 2 in the experimental group with acid etching was higher than that in the experimental group with sandblasting at 2 weeks after implantation (P < 0.05). The X-ray and CT show that the quantities of new generation bone and the degree of bone mineralization of the sandblasting group were significant lower than those of the acid etching group under the intervention of nicotine. Hematoxylin-eosin staining showed that the activity and quantity of osteoblasts around the implants down-regulated significantly, but acid etching-treated implants showed better outcomes than sandblasting-treated implants.

Objective To investigate the effects of rapamycin on tumor growth and mTOR/4E-BP1 signaling pathway in xenograft of esophageal squamous cell carcinoma ( ESCC ) EC9706 cells. Methods The expression of factors in mTOR/4E-BP1 signaling pathway of the tumor tissues was analyzed by RT-PCR and Western blot. Results Both rapamycin and cisplatin significantly inhibited the growth of transplantable tumors as compared to control group ( P < 0. 05 ) and their combination had a synergestic effect. The results of RT-PCR and Western blot show that rapamycin significantly decreased the expression of Mtor and p-4E-BP1 but increased the expression of 4E-BP1. Conclusion Rapamycin inhibits the mTOR/4E-BP1 signalling pathway, resulting in the growth inhibition of xenograft of EC9706 cells.

Objective To investigate the osteogenesis capability of different frequency extracorporeal shock wave.Methods 39 rabbits received different frequency extracorporeal shock wave at the middle potion of tibia for 3 or 7 days,these rabbits were then sac rificed and the tibia bones were collected to process for HE and toluidine blue staining,the pathological changes were observed under the light microscope.Results After different frequency extracorporeal shock wave treatment,the typical periosteal reaction were observed,external periosteum bleeded and thickened but there was no reaction at internal periosteum,marrow cavity opened and fibrosed.the osteoblast-1iking cell proliferated,however,no cartilage cells were observed;The rabbits received 7 days shock wave treatment showed more severe reaction than those for 3 days.The shock wave at lower frequency showed more severe reaction than higher frequency.Conclusion shock wave induced osteogenesis through the periosteal reaction of external periosteum;the osteogenesis capability of different frequency extracorporeal shock wave were affected by the frequency.Higher frequency of shock wave was not the ideal way to promote osteogenesis.

Objective To observe whether sodium arsenite(NaAsO2)can activate the expressions of hemeoxygenase-1(HO-1)of normal human liver cell line named Chang liver.Methods Chang liver cells were exposed to NaAsO2 at 10 μmoL/L,0(contml),2,6,12,24 h and at 0(control),5,10,25,50 μmol/L in 12 h, followed by the measuring of the expressions of HO-1 protein in ceUs with western blot.Results In 10 μmol/L groups Chang liver cells exposed for 6,12,24 h cultured in vitro,the expressions of HO-l protein(3.97±0.72, 12.92±2.98,23.29±3.82)was significantly higher than that of control(1.00±0.00),and compared with the control, the difference being statistically significant(F=85.83,P＜0.01;t=-9.42,-8.95,-13.83,respectively,P＜ 0.05 or＜0.01).In 12 h,5,10,25 and 50 μmol/L groups cultured in vitro,the expressions of HO-1(16.34±0.25, 7.75±0.39,7.93±0.14,12.48±0.35)was significantly higher than that of control(1.00±0.00).and compared with the control,the difference being statistically significant(F=85.83,P＜0.01;t=-36.25,-30.19,-86.40, -56.40,respectively,all P＜0.01).Conclusion Inorganic arsenic call induce the activation of HO-1,promote the expression of protein in a time-and dose-dependent manner.

BACKGROUNDRetroviral vectors have been widely used to introduce foreign into various target cells in vitro, thus showing relatively high systemic delivery efficiency of various transgene products. The authors investigated the stability and efficiency of skeletal muscle-specific hybrid retroviral vectors in expression of human factor IX (FIX) in vitro and iv vivo.

METHODSFIX cDNA in LIXSN vector was replaced with a FIX minigene containing splicing donor and splicing acceptor sequence of first intron of human FIX gene. Two copies of muscle creatine kinase enhancer (MCK, Me2) were inserted in forward or reverse orientation at NheI site of 3' long terminal repeat (LTR), resulting in two hybrid vectors, which were designated as LMe2IXm2SN(F) and LMe2IXm2SN(R), respectively. The vectors were tested in vitro and in vivo for stability and muscle-specificity of factor IX expression with SCID mice.

RESULTSMuscle cells carrying vector with Me2 expressed significantly higher levels of FIX (up to 1800 ng/106.24 h) than those without Me2, thus suggesting that Me2 could specifically increase expression level of FIX in muscle cells. Myoblasts transduced with LMe2IXm2SN(R) produced much less FIX in vivo in SCID mice than LMe2IXm2SN(F). One or two copies of Me2 sequence were deleted in myoblasts transduced with LMe2IXm2SN(R) without changing the orientation of Me2.

CONCLUSIONSLTR inserted with MCK enhancers can specifically increase human FIX expression in skeletal muscle cells in vitro and in vivo, and MCK enhancer should be positioned in the same orientation as that of LTR promoter.

Animals ; Creatine Kinase ; genetics ; Creatine Kinase, MM Form ; Enhancer Elements, Genetic ; Factor IX ; analysis ; genetics ; Gene Expression ; physiology ; Genetic Techniques ; Genetic Vectors ; Hybridization, Genetic ; Isoenzymes ; genetics ; Mice ; Mice, SCID ; Retroviridae ; genetics ; Terminal Repeat Sequences

OBJECTIVETo develop a quantitative analytical procedure of scopolamine and atropine in Flos Daturae using RP-HPLC.

METHODThe two alkaloids were separated on a Hypersil BDS C18 column (4.6 mm x 250 mm, 5 microm) with a mobile phase of 0.02 mol x L(-1) sodium acetate buffer (containing 0.02% triethanolamine and the pH was adjusted to 6.0 with acetic acid)-methanol (60:40) and a detection wavelength of 215 nm. The flow rate was 1.0 mL x min(-1) and the column temperature was maintained at room temperature.

RESULTThe mean recovery was (99.6 +/- 1.8)% for scopolamine and (100.4 +/- 1.5)% for atropine.

CONCLUSIONThis method was simple, accurate and sensitive.

Atropine ; analysis ; Chromatography, High Pressure Liquid ; methods ; Datura ; chemistry ; Flowers ; chemistry ; Plants, Medicinal ; chemistry ; Reproducibility of Results ; Scopolamine Hydrobromide ; analysis

Attention deficit hyperactivity disorder (ADHD) is one of the most common mental disorders in childhood,with a high heritability about 60％ to 90％.Serotonin is a monoamine neurotransmitter.Numerous studies have reported the association between the serotonin receptor family (5-HTR) gene polymorphisms and ADHD,but the results are still controversial.In this study,we conducted a meta-analysis of the association between 5-HTR1B,5-HTR2A,and 5-HTR2C genetic variants and ADHD.The results showed that the 861G allele of 5-HTR1B SNP rs6296 could significantly increase the risk of ADHD (OR=1.09,95％ CI:1.01-1.18);the 5-HTR2C gene rs518147 (OR=1.69,95％ CI:1.38-2.07) and rs3813929 (OR =1.57,95％ CI:1.25-1.97) were all associated with the risk of ADHD.In addition,we also carried on a casecontrol study to explore the relevance between potential candidate genes 5-HTR 1 A,5-HTR1E,5-HTR3A and ADHD.The results indicated that 5-HTR1A rs6295 genotype (CC+CG vs.GG OR=2.00,95％ CI:1.23-3.27) and allele (OR=1.77,95％ CI:1.16-2.72) models were statistically significantly different between case group and control group.This study is the first comprehensive exploration and summary of the association between serotonin receptor family genetic variations and ADHD,and it also provides more evidence for the etiology of ADHD.