Objective:To establish three-dimensional(3D)finite element model of the mandible first molar,and to study the stress distribution.Methods:3D finite element model of the mandible first molar was constructed by CT image reconstruction technique.Then MIMICS software was used to separate the areas and finish 3D calculation.GEOMAGIC software was applied to modify and generate a NURBS surface in each patch.All components of the model were assembled under the ANSYS preprocessor.Specific material parame-ters were selected to simulate the various restoration and dentin status.The 3D finite element model was applied to analyze the stress distribution of the molar under 1 4 different pressure loading conditions.Results:The 3D finite element model of the mandible first molar was established,which was consistent to the situation observed in the clinical environment.The pressure loading n2,n8,n9,n1 0,n1 1 , n1 2,n1 3,n1 4 can be used to represent the bite pressure.Conclusion:It is a practical and accurate way to establish 3D finite element model by CT image reconstruction technique and reverse engineering software MIMICS and GEOMAGIC.

Objective:To establish three-dimensional(3D) finite element models of the first mandibular molar restored with three post and core systems.Methods:Three 3D finite element models of the restored first mandibular molars were constructed by using CT image reconstruction technique.Then MIMICS software was used to separate the areas and to finish 3D calculation.GEOMAGIC software was applied to modify and generate a NURBS surface in each patch.All components of the models were assembled under the ANSYS preprocessor.Specific materials parameters were selected to simulate the various restoration and dentin status.Results:The 3D finite element models of restored first mandible molars were successfully established,which were consistent to the situation observed in the clinical environment.Conclusion:It is a practical and accurate method to establish three-dimensional finite element models by CT image reconstruction technique and reverse engineering software MIMICS and GEOMAGIC.

Objective To investigate the clinical efficacy of lengthening osteotomy for leg bone defect. Methods The clinical data of 22 patients who received lengthening osteotomy for leg bone defect from February 2005 to March 2011 were retrospectively analyzed. Operative methods were designed according to the patients' general condition, condition of fracture nonunion and bone defect accompanied by osteomyelitis. They included Z-shaped, oblique, and cortical bone osteotomy. The modified Ilizarov external fixator was used after osteotomy. Bone lengthening was performed 1 week after the operation, and the lengthening rate was 0.5-1mm/d. Results The bone defects achieved bone union in the 22 patients by fixation and lengthening for 3-10 months (8 months on average), followed by external fixation for 6 months to achieve clinical union. The follow-up period for all the patients ranged from 12 to 15 months, and remediable complication was found in 2 patients (1 mild, 1 moderate), and no irredeemable complication was observed. Conclusions Lengthening osteotomy is safe, reliable, and easy to operate. Furthermore postoperative nursing care is simple and complications are less, thus it is an ideal surgical method for leg bone defect.

Objective To investigate the changes of iodide uptake and the expression of thyroidspecific genes in poorly differentiated follicular thyroid carcinoma (FTC) cells after transfection of human TSH receptor (hTSHR) gene in vitro. Methods The recombinant eukaryotic expression plasmid PcDNA3. 1/hTSHR-cDNA was transformed into DH5a bacterial for amplification and then the recombinant plasmid was extracted. The recombinant was identified with PCR amplifying, restriction enzyme digestion analysis and DNA sequencing. The recombinant plasmid pcDNA3.1/hTSHR was transfected into FTC-133 cell line by lipofectin methodin vitro. Immunofluorescence, iodide uptake studies and real time-PCR were applied to detect target protein expression. Statistical analysis was performed with t-test using SPSS 13. 0 software. Results Kpn Ⅰ and Xba Ⅰ restriction enzyme digestion, PCR amplifying and DNA sequencing confirmed that pcDNA3. 1/hTSHR was successfully constructed. After transfection of the recombinant plasmid pcDNA3. 1/hTSHR-cDNA and the stimulation of hTSH, the tumor cells displayed the expression of hTSHR protein at cell surface and cytoplasm. The iodine uptake in pcDNA3. 1/hTSHR transfected cells was 2. 9 times higher than that of control(pcDNA3.1(+) transfected cells) group(t = 28.63, P ＜0. 01). The expression of TSHR,NIS, TPO and Tg (mRNA levels) in pcDNA3. 1/hTSHR transfected cells were also significantly elevated by 1.74 (t =5.959, P＜0.01), 7.2 (t =3.807,P＜0.05), 2.88 (t=4.769,P＜0. 01) and 2.67 times (t=6.388,P ＜0.01) respectively compared to those of the control group. Conclusion The study demonstrates that iodide uptake may be reactivated by hTSHR receptor gene transfection in poorly differentiated FTC cell.

OBJECTIVETo identify the mutations of iduronate-2-sulfatase (IDS) gene, and to establish a basis of prenatal gene diagnosis of Hunter syndrome.

METHODSUrine glycosaminoglycan (GAG) assay was used to preliminary diagnosis of mucopolysaccharidosis. PCR-denaturing high-performance liquidchromatograptly (PCR-DHPLC) analysis was performed to detect the mutation in exons 9, 3, 8 of the IDS gene. DNA sequencing was applied to analyze the mutation detected by PCR-DHPLC.

RESULTSAbnormal peaks were found by PCR-DHPLC. A new frame-mutation (1569+TT) in exon 9 of IDS gene was identified by DNA sequencing. Two "T"q inserted in position 1569 base pair (1569+TT) caused a substitution of codon 482 (TTA, leucine) to 482 (TTT, phenylalanine). The "TT" insertion results in the decrease of amino acids from 550 to 482. The patient is a hemizygote and his mother is a heterozygote.

CONCLUSIONA new frame-shift mutation of IDS gene is found to report. The mutation (1569+TT) results in 68 amino acids lost. Probably it causes the enzyme activity seriously dropped down and being pathologically the basis of disease.

Child, Preschool ; Chromatography, High Pressure Liquid ; DNA Mutational Analysis ; Humans ; Iduronate Sulfatase ; genetics ; Male ; Molecular Sequence Data ; Mucopolysaccharidoses ; genetics ; Mucopolysaccharidosis II ; enzymology ; genetics ; Mutation

The paper introduces a helical tomotherapy (HT) adaptive system in assessment of parotid gland dose variation in head and neck cancer. The system, which helical therapy unit is equipped with, is based on megavoltage computed tomography (MVCT) images to calculate the actual volume and dose of region of interest (ROI). Whether to change plan is judged on the fact for the realization of adaptive radiotherapy. One case of nasopharyngeal carcinoma was as a sample to evaluate parotid gland dose variation during the treatment. On every week and last time, patient was scanned by MVCT before treatment, a total of eight MVCT images. As the treatment progressed, the parotid gland volume was shrinking and the dose was increasing. The parotids volume variation was negatively related with D50 and V1 (both P < 0.05).
Adult ; Head and Neck Neoplasms ; diagnostic imaging ; Humans ; Male ; Parotid Gland ; diagnostic imaging ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; instrumentation ; methods ; Software ; Tomography, Spiral Computed ; instrumentation ; methods

Adult ; Cartilage ; pathology ; surgery ; Female ; Humans ; Metatarsophalangeal Joint ; pathology ; Sesamoid Bones ; pathology ; surgery

OBJECTIVETo study the molecular mechanism of the inhibitory effects of vitamin C on benzo[a]pyrene (B[a]P)-induced changes of cell cycle in human embryo lung fibroblast (HELF) cells.

METHODSThe stable transfectants, HELF transfected with antisense cyclin D1 and antisense CDK4, were established. Cells were cultured and pretreated with vitamin C before stimulation with B[a]P for 24 h. The expression levels of cyclin D1, CDK4, E2F1, and E2F4 were determined by Western blot. Flow cytometric analysis was employed to detect the distributions of cell cycle.

RESULTSB[a]P significantly elevated the expression levels of cyclin D1, E2F1, and E2F4 in HELF cells. Vitamin C decreased the expression levels of cyclin D1, E2F1, and E2F4 in B[a]P-stimulated HELF cells. Dose-dependent relationships were not found between the different concentrations of vitamin C (10, 100, 500, 1000, and 5000 micromol/L) and the expression levels of cyclin D1, E2F1, and E2F4 in HELF cells. The expression levels of cyclin D1, E2F1, and E2F4 in B[a]P-treated transfectants were lower than those in B[a]P-treated HELF cells. The expression levels of cyclin D1 and E2F4 treated with vitamin C and antisense cyclin D1 were decreased compared with those treated with antisense cyclin D1 alone. The effects of vitamin C combined with antisense CDK4 on the expression levels of cyclin D1 and E2F1/E2F4 were similar to those of antisense CDK4 alone. B[a]P progressed HELF cells from G1 to S phase. Both vitamin C and antisense cyclin D1 suppressed the changes of cell cycle progressed by B[a]P. However, antisense CDK4 did not attenuate the above changes. Vitamin C combined with antisense CDK4 markedly suppressed B[a]P-induced changes of cell cycle as compared with antisense CDK4. But the inhibitory effects of vitamin C combined with antisense cyclin D1 on B[a]P-induced changes of cell cycle were similar to those of vitamin C alone or antisense cyclin D1 alone.

CONCLUSIONSB[a]P progressed HELF cells from G1 to S phase via intracellular signaling pathway of cyclin D1/E2F. Vitamin C may modulate this signaling pathway to protect cells from injury caused by B[a]P.

Ascorbic Acid ; pharmacology ; Benzo(a)pyrene ; Blotting, Western ; methods ; Cell Cycle ; drug effects ; physiology ; Cells, Cultured ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Dose-Response Relationship, Drug ; E2F1 Transcription Factor ; metabolism ; Fibroblasts ; cytology ; drug effects ; metabolism ; G1 Phase ; drug effects ; physiology ; Humans ; Lung ; cytology ; embryology ; RNA, Antisense ; genetics ; S Phase ; drug effects ; physiology ; Transfection ; methods

OBJECTIVETo investigate the relationship between complex 1311 mutation of C-->T in exon 11 and 93 T-->C in intron 11 of G6PD gene and the G6PD deficiency.

METHODSUsing NBT paper strip method to screen and quantitative NBT method to confirm G6PD deficiency. PCR-SSCP technique was used to find the abnormal exon 11 and the amplification refractory mutation system (ARMS) to identify 1311 mutation, and DNA sequencing to identify the complex mutation at 1311 in exon 11 and 93 in intron 11.

RESULTSAbnormal band in exon 11 was found in 12 cases. DNA sequencing showed that they were 1311 mutation together with 93 mutation.

CONCLUSIONThis complex mutation may be the cause of reduced activity of G6PD enzyme.

Base Sequence ; DNA Mutational Analysis ; Exons ; genetics ; Genetic Testing ; Glucosephosphate Dehydrogenase ; genetics ; Glucosephosphate Dehydrogenase Deficiency ; diagnosis ; enzymology ; genetics ; Humans ; Introns ; genetics ; Molecular Sequence Data ; Point Mutation ; Polymerase Chain Reaction ; Polymorphism, Single Nucleotide ; Polymorphism, Single-Stranded Conformational

OBJECTIVEOf denaturing high performance liquid chromatography (DHPLC), a technique platform was developed for screening G6PD deficient variants.

METHODSWhen applied to screen and identify the G6PD deficient variants from 124 patients who come from 11 nations in China, the DHPLC was compared with amplification refractory mutation system (ARMS) or DNA sequence technique and assessed carefully in its accuracy, sensitivity, efficiency and the cost of experiment.

RESULTSThe G6PD-deficient variants, such as 1388 G-->A (36/124 cases), 1376 G-->T(35), 95 A-->G (14), 1024 C-->T (3), 392 G-->T (4), 871 G-->A /1311 C-->T /IVS XI +93 t-->c (9), 871 G-->A (1), 1311 C-->T/IVS XI +93 t-->c (4), 1376 G-->T /1388 G-->A (1) and so on, were characterized as sharp peaks by DHPLC and verified by DNA sequence. Further, the standard chromatograms were put into database for 8 kinds of common G6PD deficient variants in Chinese populations. And also DHPLC found 3 G6PD variants (1388 G-->A) from 103 negative controls. With taking 8.8 minutes and costing 1 dollar for each sample, DHPLC successfully detected and identified 34 heterozygous females from patients with G6PD deficiency. However, ARMS checked 83 positive controls but got 12 false G6PD mutants, of which 5 were false positive, 7 false negative. Above results show that DHPLC sounds like to be more convenience, sensitive and accurate than ARMS and DNA sequence techniques for checking G6PD mutants.

CONCLUSIONDHPLC is of great advantage to screen the G6PD deficient variants with accuracy, convenience, automation and less cost, and significantly to identify the female heterozygote and clinical type IV individuals with G6PD deficiency.

Chromatography, High Pressure Liquid ; methods ; DNA Mutational Analysis ; Female ; Glucosephosphate Dehydrogenase ; genetics ; Glucosephosphate Dehydrogenase Deficiency ; diagnosis ; genetics ; Humans ; Male ; Mutation ; Reproducibility of Results